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Publisher: Elsevier   (Total: 3157 journals)

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Showing 1201 - 1400 of 3161 Journals sorted alphabetically
Graphical Models     Hybrid Journal   (Followers: 3, SJR: 0.454, CiteScore: 2)
Groundwater for Sustainable Development     Full-text available via subscription   (Followers: 3, SJR: 0.329, CiteScore: 1)
Growth Factors and Cytokines in Health and Disease     Full-text available via subscription   (Followers: 1)
Growth Hormone & IGF Research     Hybrid Journal   (Followers: 16, SJR: 1.059, CiteScore: 2)
Gynecologic Oncology     Hybrid Journal   (Followers: 25, SJR: 2.339, CiteScore: 4)
Gynecologic Oncology Reports     Open Access   (Followers: 10, SJR: 0.307, CiteScore: 1)
Gynécologie Obstétrique & Fertilité     Full-text available via subscription   (Followers: 1)
Habitat Intl.     Hybrid Journal   (Followers: 6, SJR: 1.336, CiteScore: 3)
Hand Clinics     Full-text available via subscription   (Followers: 5, SJR: 0.556, CiteScore: 1)
Hand Surgery and Rehabilitation     Full-text available via subscription   (Followers: 4, SJR: 0.358, CiteScore: 1)
Handai Nanophotonics     Full-text available via subscription  
Handbook of Adhesives and Sealants     Full-text available via subscription   (Followers: 2)
Handbook of Agricultural Economics     Full-text available via subscription   (Followers: 3)
Handbook of Algebra     Full-text available via subscription  
Handbook of Analytical Separations     Full-text available via subscription   (Followers: 3)
Handbook of Behavioral Neuroscience     Full-text available via subscription   (Followers: 3)
Handbook of Biological Physics     Full-text available via subscription  
Handbook of Chemical Neuroanatomy     Full-text available via subscription  
Handbook of Clinical Neurology     Full-text available via subscription   (Followers: 2, SJR: 1.007, CiteScore: 2)
Handbook of Clinical Neurophysiology     Full-text available via subscription  
Handbook of Complex Analysis     Full-text available via subscription  
Handbook of Computational Economics     Full-text available via subscription   (Followers: 1, SJR: 4.16, CiteScore: 2)
Handbook of Defense Economics     Full-text available via subscription   (Followers: 1)
Handbook of Development Economics     Full-text available via subscription   (Followers: 7)
Handbook of Differential Equations: Evolutionary Equations     Full-text available via subscription  
Handbook of Differential Equations: Ordinary Differential Equations     Full-text available via subscription  
Handbook of Differential Equations: Stationary Partial Differential Equations     Full-text available via subscription   (Followers: 2)
Handbook of Differential Geometry     Full-text available via subscription  
Handbook of Dynamical Systems     Full-text available via subscription   (Followers: 1)
Handbook of Econometrics     Full-text available via subscription   (Followers: 8)
Handbook of Economic Forecasting     Full-text available via subscription   (Followers: 1)
Handbook of Economic Growth     Full-text available via subscription   (Followers: 2)
Handbook of Environmental Economics     Full-text available via subscription   (Followers: 2)
Handbook of Experimental Economics Results     Full-text available via subscription   (Followers: 4)
Handbook of Exploration and Environmental Geochemistry     Full-text available via subscription   (Followers: 2)
Handbook of Exploration Geochemistry     Full-text available via subscription   (Followers: 1)
Handbook of Ferromagnetic Materials     Full-text available via subscription   (Followers: 1)
Handbook of Game Theory with Economic Applications     Full-text available via subscription   (Followers: 1)
Handbook of Geophysical Exploration: Seismic Exploration     Full-text available via subscription  
Handbook of Health Economics     Full-text available via subscription   (Followers: 10)
Handbook of Immunohistochemistry and in Situ Hybridization of Human Carcinomas     Full-text available via subscription   (Followers: 1)
Handbook of Income Distribution     Full-text available via subscription   (Followers: 2)
Handbook of Industrial Organization     Full-text available via subscription   (Followers: 3)
Handbook of Intl. Economics     Full-text available via subscription  
Handbook of Labor Economics     Full-text available via subscription   (Followers: 14)
Handbook of Law and Economics     Full-text available via subscription   (Followers: 17)
Handbook of Macroeconomics     Full-text available via subscription   (Followers: 6, SJR: 0, CiteScore: 2)
Handbook of Magnetic Materials     Full-text available via subscription   (Followers: 2, SJR: 0.467, CiteScore: 2)
Handbook of Mathematical Economics     Full-text available via subscription  
Handbook of Mathematical Fluid Dynamics     Full-text available via subscription   (Followers: 2)
Handbook of Metal Physics     Full-text available via subscription  
Handbook of Monetary Economics     Full-text available via subscription   (Followers: 5)
Handbook of Natural Resource and Energy Economics     Full-text available via subscription   (Followers: 3)
Handbook of Numerical Analysis     Full-text available via subscription   (Followers: 4)
Handbook of Perception and Action     Full-text available via subscription   (Followers: 2)
Handbook of Petroleum Exploration and Production     Full-text available via subscription   (Followers: 2)
Handbook of Population and Family Economics     Full-text available via subscription   (Followers: 4)
Handbook of Powder Technology     Full-text available via subscription   (Followers: 6)
Handbook of Public Economics     Full-text available via subscription   (Followers: 1)
Handbook of Regional and Urban Economics     Full-text available via subscription   (Followers: 1)
Handbook of Sensors and Actuators     Full-text available via subscription   (Followers: 10)
Handbook of Social Choice and Welfare     Full-text available via subscription   (Followers: 3)
Handbook of Statistics     Full-text available via subscription   (Followers: 7, SJR: 0.102, CiteScore: 0)
Handbook of Surface Science     Full-text available via subscription   (Followers: 4, SJR: 0.193, CiteScore: 0)
Handbook of Systemic Autoimmune Diseases     Full-text available via subscription   (Followers: 2)
Handbook of the Economics of Art and Culture     Full-text available via subscription   (Followers: 1)
Handbook of the Economics of Education     Full-text available via subscription   (Followers: 9, SJR: 0, CiteScore: 2)
Handbook of the Economics of Finance     Full-text available via subscription   (Followers: 6)
Handbook of the Economics of Giving, Altruism and Reciprocity     Full-text available via subscription  
Handbook of the Geometry of Banach Spaces     Full-text available via subscription   (Followers: 1)
Handbook of the History of Logic     Full-text available via subscription   (Followers: 1)
Handbook of Thermal Analysis and Calorimetry     Full-text available via subscription   (Followers: 1)
Handbook of Thermal Conductivity     Full-text available via subscription   (Followers: 4)
Handbook of Vapor Pressure     Full-text available via subscription  
Handbook on the Physics and Chemistry of Rare Earths     Full-text available via subscription   (Followers: 3, SJR: 0.755, CiteScore: 3)
Handbooks of Management Accounting Research     Full-text available via subscription   (Followers: 4)
HardwareX     Open Access  
Harmful Algae     Hybrid Journal   (Followers: 5, SJR: 1.531, CiteScore: 4)
HBRC J.     Open Access   (Followers: 2)
Health & Place     Hybrid Journal   (Followers: 15, SJR: 1.506, CiteScore: 3)
Health Outcomes Research in Medicine     Hybrid Journal   (Followers: 3)
Health Policy     Hybrid Journal   (Followers: 43, SJR: 1.252, CiteScore: 2)
Health Policy and Technology     Hybrid Journal   (Followers: 4, SJR: 0.322, CiteScore: 1)
Health Professions Education     Open Access   (Followers: 3)
Healthcare : The J. of Delivery Science and Innovation     Full-text available via subscription   (Followers: 1)
Hearing Research     Hybrid Journal   (Followers: 11, SJR: 1.35, CiteScore: 3)
Heart & Lung: The J. of Acute and Critical Care     Hybrid Journal   (Followers: 11, SJR: 0.757, CiteScore: 2)
Heart Failure Clinics     Full-text available via subscription   (Followers: 2, SJR: 1.153, CiteScore: 2)
Heart Rhythm     Hybrid Journal   (Followers: 11, SJR: 3.231, CiteScore: 4)
Heart, Lung and Circulation     Full-text available via subscription   (Followers: 9, SJR: 0.599, CiteScore: 1)
HeartRhythm Case Reports     Open Access   (SJR: 0.232, CiteScore: 0)
Heliyon     Open Access   (SJR: 0.355, CiteScore: 1)
Hellenic J. of Cardiology     Open Access   (Followers: 1, SJR: 0.479, CiteScore: 1)
Hematology, Transfusion and Cell Therapy     Open Access   (Followers: 1)
Hematology/Oncology and Stem Cell Therapy     Open Access   (Followers: 4, SJR: 0.532, CiteScore: 1)
Hematology/Oncology Clinics of North America     Full-text available via subscription   (Followers: 6, SJR: 1.282, CiteScore: 3)
Hepatobiliary & Pancreatic Diseases Intl.     Full-text available via subscription   (Followers: 2, SJR: 0.711, CiteScore: 2)
High Energy Density Physics     Hybrid Journal   (Followers: 2, SJR: 0.933, CiteScore: 2)
Hipertensión y Riesgo Vascular     Full-text available via subscription   (SJR: 0.115, CiteScore: 0)
Historia Mathematica     Full-text available via subscription   (Followers: 1, SJR: 0.174, CiteScore: 0)
History of CERN     Full-text available via subscription   (Followers: 1)
History of Neuroscience in Autobiography     Full-text available via subscription   (Followers: 3)
HIV & AIDS Review     Full-text available via subscription   (Followers: 12, SJR: 0.134, CiteScore: 0)
Homeopathy     Hybrid Journal   (Followers: 6, SJR: 0.678, CiteScore: 1)
HOMO - J. of Comparative Human Biology     Hybrid Journal   (Followers: 2, SJR: 0.335, CiteScore: 1)
Hong Kong J. of Nephrology     Open Access   (Followers: 2, SJR: 0.137, CiteScore: 0)
Hong Kong J. of Occupational Therapy     Open Access   (Followers: 42, SJR: 0.237, CiteScore: 1)
Hong Kong Physiotherapy J.     Open Access   (Followers: 13, SJR: 0.183, CiteScore: 0)
Hormigón y Acero     Full-text available via subscription  
Hormones and Behavior     Hybrid Journal   (Followers: 13, SJR: 1.638, CiteScore: 4)
Horticultural Plant J.     Open Access   (Followers: 5)
Hospital Medicine Clinics     Full-text available via subscription   (Followers: 2, SJR: 0.107, CiteScore: 0)
Human Factors in Information Technology     Full-text available via subscription   (Followers: 35)
Human Immunology     Hybrid Journal   (Followers: 17, SJR: 0.856, CiteScore: 2)
Human Movement Science     Hybrid Journal   (Followers: 15, SJR: 0.756, CiteScore: 2)
Human Pathology     Hybrid Journal   (Followers: 26, SJR: 1.304, CiteScore: 3)
Human Pathology : Case Reports     Open Access   (Followers: 2, SJR: 0.136, CiteScore: 0)
Human Resource Management Review     Hybrid Journal   (Followers: 50, SJR: 1.675, CiteScore: 4)
Hydrometallurgy     Hybrid Journal   (Followers: 13, SJR: 1.208, CiteScore: 3)
IATSS Research     Open Access   (SJR: 0.37, CiteScore: 1)
Icarus     Hybrid Journal   (Followers: 74, SJR: 2.037, CiteScore: 3)
ICT Express     Open Access   (SJR: 0.234, CiteScore: 1)
IDCases     Open Access   (SJR: 0.344, CiteScore: 1)
IERI Procedia     Open Access   (Followers: 1)
IFAC-PapersOnLine     Open Access   (SJR: 0.26, CiteScore: 1)
IIMB Management Review     Open Access   (Followers: 9, SJR: 0.24, CiteScore: 1)
IJC Heart & Vessels     Open Access   (Followers: 1)
IJC Heart & Vasculature     Open Access   (Followers: 1, SJR: 0.342, CiteScore: 1)
IJC Metabolic & Endocrine     Open Access   (Followers: 1, SJR: 0.4, CiteScore: 1)
Image and Vision Computing     Hybrid Journal   (Followers: 15, SJR: 0.612, CiteScore: 3)
Imagen Diagnóstica     Full-text available via subscription   (SJR: 0.106, CiteScore: 0)
Imagerie de la Femme     Full-text available via subscription   (Followers: 1, SJR: 0.124, CiteScore: 0)
Immunity     Full-text available via subscription   (Followers: 55, SJR: 13.393, CiteScore: 16)
Immuno-analyse & Biologie Spécialisée     Full-text available via subscription   (Followers: 2)
Immunobiology     Hybrid Journal   (Followers: 9, SJR: 1.1, CiteScore: 3)
Immunology and Allergy Clinics of North America     Full-text available via subscription   (Followers: 6, SJR: 1.132, CiteScore: 3)
Immunology Letters     Hybrid Journal   (Followers: 12, SJR: 1.168, CiteScore: 3)
Immunotoxicology of Drugs and Chemicals: an Experimental and Clinical Approach     Full-text available via subscription   (Followers: 1)
Implantodontie     Full-text available via subscription  
Indagationes Mathematicae     Open Access   (Followers: 1, SJR: 0.685, CiteScore: 1)
Indian Heart J.     Open Access   (Followers: 4, SJR: 0.333, CiteScore: 1)
Indian J. of Medical Specialities     Hybrid Journal   (SJR: 0.118, CiteScore: 0)
Indian J. of Tuberculosis     Full-text available via subscription   (SJR: 0.221, CiteScore: 0)
Indian Pacing and Electrophysiology J.     Open Access   (SJR: 0.273, CiteScore: 0)
Industrial Chemistry Library     Full-text available via subscription   (Followers: 3)
Industrial Crops and Products     Hybrid Journal   (Followers: 6, SJR: 1.091, CiteScore: 4)
Industrial Marketing Management     Hybrid Journal   (Followers: 23, SJR: 1.663, CiteScore: 4)
Industrial Safety Series     Full-text available via subscription   (Followers: 16)
Infant Behavior and Development     Hybrid Journal   (Followers: 14, SJR: 0.784, CiteScore: 2)
Infectio     Open Access   (SJR: 0.133, CiteScore: 0)
Infection, Disease & Health     Open Access   (Followers: 8, SJR: 0.23, CiteScore: 1)
Infection, Genetics and Evolution     Hybrid Journal   (Followers: 5, SJR: 1.278, CiteScore: 3)
Infectious Disease Clinics of North America     Full-text available via subscription   (Followers: 5, SJR: 2.359, CiteScore: 5)
Informatics in Medicine Unlocked     Open Access   (SJR: 0.224, CiteScore: 1)
Information & Management     Hybrid Journal   (Followers: 58, SJR: 1.628, CiteScore: 5)
Information and Computation     Hybrid Journal   (Followers: 4, SJR: 0.504, CiteScore: 1)
Information and Organization     Hybrid Journal   (Followers: 39, SJR: 1.202, CiteScore: 3)
Information and Software Technology     Hybrid Journal   (Followers: 6, SJR: 0.581, CiteScore: 4)
Information Economics and Policy     Hybrid Journal   (Followers: 4, SJR: 0.63, CiteScore: 1)
Information Fusion     Hybrid Journal   (Followers: 2, SJR: 1.832, CiteScore: 7)
Information Processing & Management     Hybrid Journal   (Followers: 353, SJR: 0.92, CiteScore: 4)
Information Processing in Agriculture     Open Access   (SJR: 0.352, CiteScore: 2)
Information Processing Letters     Hybrid Journal   (Followers: 6, SJR: 0.412, CiteScore: 1)
Information Sciences     Hybrid Journal   (Followers: 413, SJR: 1.635, CiteScore: 5)
Information Security Technical Report     Full-text available via subscription   (Followers: 12)
Information Systems     Hybrid Journal   (Followers: 13, SJR: 0.805, CiteScore: 4)
Infosecurity     Full-text available via subscription   (Followers: 11)
Infrared Physics & Technology     Hybrid Journal   (Followers: 12, SJR: 0.54, CiteScore: 2)
Injury     Hybrid Journal   (Followers: 18, SJR: 0.99, CiteScore: 2)
Injury Extra     Open Access   (Followers: 2)
Inmunología     Full-text available via subscription   (Followers: 2)
Innovative Food Science & Emerging Technologies     Hybrid Journal   (Followers: 5, SJR: 1.201, CiteScore: 3)
Inorganic Chemistry Communications     Hybrid Journal   (Followers: 13, SJR: 0.43, CiteScore: 2)
Inorganica Chimica Acta     Hybrid Journal   (Followers: 9, SJR: 0.485, CiteScore: 2)
Insect Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 3, SJR: 1.912, CiteScore: 4)
Instabilities in Silicon Devices     Full-text available via subscription   (Followers: 1)
Insulin     Full-text available via subscription   (Followers: 5)
Insurance: Mathematics and Economics     Hybrid Journal   (Followers: 9, SJR: 1.083, CiteScore: 2)
Integration, the VLSI J.     Hybrid Journal   (Followers: 6, SJR: 0.223, CiteScore: 1)
Integrative Medicine Research     Open Access   (Followers: 3)
Intellectual Economics     Open Access  
Intelligence     Hybrid Journal   (Followers: 7, SJR: 1.633, CiteScore: 3)
Intensive and Critical Care Nursing     Hybrid Journal   (Followers: 31, SJR: 0.611, CiteScore: 2)
Interdisciplinary Neurosurgery     Open Access   (SJR: 0.164, CiteScore: 0)
Interface Science and Technology     Full-text available via subscription  
Intermetallics     Hybrid Journal   (Followers: 22, SJR: 1.568, CiteScore: 4)
Internet Interventions : The application of information technology in mental and behavioural health     Open Access   (Followers: 4, SJR: 1.962, CiteScore: 4)
Interventional Cardiology Clinics     Full-text available via subscription   (Followers: 3, SJR: 0.156, CiteScore: 0)
Intl. Biodeterioration & Biodegradation     Hybrid Journal   (Followers: 1, SJR: 1.086, CiteScore: 4)
Intl. Business Review     Hybrid Journal   (Followers: 10, SJR: 1.012, CiteScore: 3)
Intl. Communications in Heat and Mass Transfer     Hybrid Journal   (Followers: 21, SJR: 1.553, CiteScore: 5)
Intl. Comparative Jurisprudence     Open Access   (Followers: 2)
Intl. Dairy J.     Hybrid Journal   (Followers: 6, SJR: 1.051, CiteScore: 2)
Intl. Economics     Hybrid Journal   (Followers: 3, SJR: 0.451, CiteScore: 1)
Intl. Emergency Nursing     Hybrid Journal   (Followers: 10, SJR: 0.461, CiteScore: 1)
Intl. Geophysics     Full-text available via subscription   (Followers: 3)
Intl. Immunopharmacology     Hybrid Journal   (Followers: 2, SJR: 1.051, CiteScore: 3)
Intl. J. for Parasitology     Hybrid Journal   (Followers: 11, SJR: 1.638, CiteScore: 4)
Intl. J. for Parasitology : Drugs and Drug Resistance     Open Access   (Followers: 4, SJR: 1.556, CiteScore: 4)
Intl. J. for Parasitology : Parasites and Wildlife     Open Access   (Followers: 2, SJR: 1.455, CiteScore: 3)

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Journal Cover
Journal Prestige (SJR): 1.208
Citation Impact (citeScore): 3
Number of Followers: 13  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0304-386X
Published by Elsevier Homepage  [3157 journals]
  • Energy-efficient mineral carbonation of CaSO4 derived from wollastonite
           via a roasting-leaching route
    • Abstract: Publication date: Available online 11 January 2019Source: HydrometallurgyAuthor(s): Xingliang Xu, Weizao Liu, Guanrun Chu, Guoquan Zhang, Dongmei Luo, Hairong Yue, Bin Liang, Chun Li Mineral carbonation is an important technique for the sequestration of carbon dioxide (CO2) on a large scale. In this article, indirect carbonation of abundant wollastonite [CaSiO3] mineral combined with the use of a CO2 mineralization cell (CMC) for the recovery of mineralization energy has been proposed. The results of thermodynamic analysis reveal that the described process consumes 73% less energy than that required for the route, in which serpentine is utilized as the mineralization agent. During this process, calcium sulfate (CaSO4) was first derived with recyclable ammonium sulfate (AS) via a roasting-leaching route. The gaseous ammonia produced during the roasting stage was used to capture CO2 from a mixture of flue gases and simultaneously generate ammonium bicarbonate (NH4HCO3) and electricity by the CMC. The obtained NH4HCO3 solution reacted directly with the leaching slurry to mineralize CO2 and regenerate AS at the same time. In this study, process parameters of this route were investigated in detail, and the related extraction mechanism was discussed. It was found that 94.5% of calcium species in wollastonite was converted into CaSO4, 94.8% of which was subsequently carbonated. The extraction efficiency of the roasting stage did not exceed 39% due to its low mass transfer rate resulting from the high viscosity of liquid ammonium bisulfate and presence of silicon dioxide (SiO2) and CaSO4 species on the surface of unreacted wollastonite. Preliminary energy analysis showed that a net reduction of CO2 emission of about 347 kg could be achieved for the mineralization of 1000 kg of CO2.
  • Uranium and molybdenum recovery from copper leaching solutions using ion
    • Abstract: Publication date: Available online 5 January 2019Source: HydrometallurgyAuthor(s): Pedro Orrego, José Hernández, Alonso Reyes This work shows the technical feasibility to recover uranium and molybdenum from industrial copper leaching solutions (PLS). Both were obtained as by-products from hydrometallurgical operations of the Chilean copper mining industry, using the ion exchange technique. This process recovered uranium and molybdenum, without disturbing or changing the normal operation of the overall copper production process. Uranium concentration was 17 mg/L, while molybdenum concentration was 50 mg/L. Four different anionic resins were tested, along with the influence of impurities over the breakthrough and saturation points achieved. In a first instance, two resins were chosen based on their Langmuir parameters, namely, maximum load capacity (Qmax) and separation factor (RL): L-MP62 and M43. The overall dynamic process consisted in a pre-conditioning step for the resin, using a weak hydrochloric acid solution. Next, the copper PLS solution feeds the fixed bed of the ion exchange column. Once the PLS solution saturates the anionic resin, a hydrochloric solution extracts uranium, and a sodium hydroxide solution extracts molybdenum. The final products were purified elution solutions with 500 mg/L uranium and 800 mg/L molybdenum, respectively.
  • Recovery of nickel and molybdate from ammoniacal leach liquors of spent
           HDS catalysts using chelating ion exchange resin
    • Abstract: Publication date: Available online 3 January 2019Source: HydrometallurgyAuthor(s): Bharat Padh, P.C. Rout, G.K. Mishra, K.R. Suresh, B. Ramachandra Reddy Spent hydrodesulphurization (HDS) catalysts containing valuable Mo and Ni ions are potential source for the recovery of Mo and Ni from the point of commercial, environmental and conservation of natural mineral resources. In the present study, oxidative roasting of spent HDS catalyst followed by ammonia leaching results in the leach liquor with about 15.3 g/L Mo (~85% recovery), ~125 g/L (NH4)2SO4 and ~0.9 g/L Ni as impurity. Therefore Ni separation from this ammoniacal molybdate leach liquor is essentially the first step to obtain high pure molybdate and ammonium sulfate solution. In this study, separation of nickel from ammoniacal molybdate leach liquor was reported using commercial chelating iminodiacetate resin, Lewatit TP207 by batch and column methods. Optimization of process parameters include equilibration time, acidity of leach liquor, aqueous flow rate, metal concentration, loading capacity of resin for Ni during sorption of Ni, desorption of nickel from loaded resin and stability and reuse of resin in continuous column experiments. Feed leach liquor of pH>8.0 is important to achieve clear separation of Ni from Mo. Loading capacity of resin and break through curves are optimized to achieve
  • Recovery of Pd(II) and Pt(IV) from leach liquors of automotive catalysts
           with calixarene-based di-n-alkylamino extractants in saturated hydrocarbon
    • Abstract: Publication date: Available online 3 January 2019Source: HydrometallurgyAuthor(s): Manabu Yamada, Yu Kaneta, Muniyappan Rajiv Gandhi, Uma Maheswara Rao Kunda, Atsushi Shibayama The solubilities of eight p-di-n-alkylaminomethylcalix[4]arenes (alkyl: methyl to n-octyl = 1–8) in saturated hydrocarbon diluents commonly used as industrial diluents were investigated. Calixarene-based amino extractants with longer alkyl chains dissolved more readily in the saturated hydrocarbon diluents. Although 8 dissolved in kerosene, 1-decanol had to be added as a “phase modifier’” in order to inhibit the formation of a third phase on the Pd(II) and Pt(IV) extraction systems. The optimal mixing ratio of kerosene with 1-deconol was found to be 50:50 (v/v%). Pd(II) and Pt(IV) were effectively recovered from the leach liquors of automotive catalysts using 8 and this kerosene/1-decanol mixed diluent. Furthermore, the results of reusability tests performed using the regenerated organic phase consisting of 8 and the kerosene/1-decanol mixed diluent indicate that Pd(II) and Pt(IV) were extracted at relatively high efficiencies even after five extraction/stripping cycles.Graphical abstractUnlabelled Image
  • Can hydrogen sulphide gas be produced during alkaline leach of enargitic
           copper concentrates'
    • Abstract: Publication date: Available online 3 January 2019Source: HydrometallurgyAuthor(s): Gonzalo Montes-Atenas, Rodrigo Ladrón de Guevara, Katherine Lizama-Allende, F. Valenzuela The usual answer to the question stated in the title of this manuscript would be a definitive no due to the high stability of dissolved sulphide ions in water under strong alkaline conditions; nevertheless, experimental results presented in this research shows the opposite. Two arsenic-bearing copper concentrates coming from two different Chilean mine sites were used to carry out alkaline sulphide leach experiments. One of them (Concentrate 1) exhibits a P80 of 45 μm and 3.8% arsenic while the other (Concentrate 2) has a P80 of 98 μm and 2.3% arsenic. The arsenic extractions at 60 and 90 °C after 2 h reaction for concentrates 1 and 2 are around 10 and 80% and 14 and 93%, respectively.More relevantly, notwithstanding the strong alkaline conditions used in the experiments, the production of toxic hydrogen sulphide gas was detected and measured in tests performed at 90 °C. The molar ratio between the arsenic leached and the formation of hydrogen sulphide is 20:1 and 5:1 for concentrate 1 and 2, respectively. Stoichiometric computations associated to the mechanisms of carbonation of alkaline solutions and to the thermodynamic predominance of H2S at high pH values cannot fully explain the significant quantity of gas formed during the leaching process. One hypothesis to explain the formation of the gas is mineralogy related. It involves the occurrence of specific parallel secondary reactions taking place at the solid-liquid interface triggering the increase of the local acidity and producing the gas. Due to the high concentration of sulphide ions in solution and the high temperature conditions, the gas is not fully scrubbed by the strong alkaline solution. Looking at the mineralogy of the gangue material in both concentrates, the mass ratio of the gas produced between both concentrate matches the mass ratio of galena, haematite, goethite and kaolinite present in both concentrates suggesting that these minerals would be responsible for producing the gas. Reactions associated to each one of the mentioned species are presented suggesting two different mechanisms for local acidification. This finding would have a strong impact on the implementation of the process at large scale safety-wise.
  • Dephosphorization of unroasted oolitic ores through alkaline leaching at
           low temperature
    • Abstract: Publication date: Available online 31 December 2018Source: HydrometallurgyAuthor(s): Long Zhang, Richard Machiela, Prajesh Das, Mingming Zhang, Timothy Eisele Roasting followed by acid leaching has long been an established dephosphorization technique for processing the goethite iron ore in the past. However, given the high-energy requirement in the process, there still exists further room for improvement. The present study of phosphorus removal from an unroasted iron ore via alkaline leaching method examined the possibility of dephosphorization from goethite ore at low temperature. The iron ore concentrate used in this study is an oolitic type of iron ore consisting primarily of goethite, in which phosphorus does not form a discrete mineral phase, but instead is diffused throughout the entire volume of the ore. This study reveals that the reduction of particle size, the increase in both temperature and hydroxyl ion [OH¯] concentration all promote phosphorus removal. About 50% of the phosphorus can be removed in relatively low [OH¯] concentration (1.25 M), about 80% phosphorous removal was attained after further increasing the [OH¯] concentration to 15 M resulting in 0.1% phosphorus in final solids with no iron losses, which was comparable to roasting followed by acid-leaching route. The optimum conditions was identified as temperature of 85 °C, [OH¯] concentration of 15 M, 0.025–0.038 mm particle size, and 10 min of leaching time with S/L ratio of 0.25 g/ml, in which P level can be reduced from 0.73 to about 0.1 wt%P. Additionally, leaching solution was demonstrated to be readily regenerated using hydrated-lime with comparable leaching ability in terms of phosphorus removal compared to fresh solution. No significant mineralogical change observed other than the uniform removal of phosphorus during the process.
  • Leaching of synthetic Ca3WO6 with ammoniacal ammonium carbonate solution
           under atmospheric pressure: A fundamental study
    • Abstract: Publication date: Available online 31 December 2018Source: HydrometallurgyAuthor(s): Xiangming Xu, Kechao Zhou, Xiaobin Li, Qiusheng Zhou, Tiangui Qi, Guihua Liu, Zhihong Peng In (NH4)2CO3 solution, leaching Ca3WO6-bearing product converted from tungsten concentrate can directly obtain ammonium tungstate solution, and thus eliminates high-salinity wastewater discharge in ammonium paratungstate manufacture. Possible reactions of Ca3WO6 leaching in aqueous ammoniacal ammonium carbonate solution under atmospheric pressure were investigated thermodynamically and experimentally. The results show that tungsten in Ca3WO6 can be efficiently leached out by forming CaCO3(s) and (NH4)2WO4 (aq) in aqueous ammoniacal ammonium carbonate solution, while raising ratio of total ammonia to total carbon in solution and forming calcite are beneficial to increase the WO3 leaching ratio. Whereas the secondary reactions of Ca3WO6 with H2O and/or Ca (OH)2/CaCO3 with (NH4)2WO4 may occur and thus CaWO4 forms in the leaching, decreasing WO3 leaching ratio especially in concentrated (NH4)2WO4 solution and in case of forming vaterite. In addition, a three-layer cover was observed on the unreacted Ca3WO6 and hinders the leaching process. Through simultaneous grinding and leaching, both high WO3 leaching ratio and high WO3 concentration leachate can be achieved by increasing ratio of total ammonia to total carbon in NH3-(NH4)2WO4- (NH4)2CO3-H2O system. These results are helpful to optimize the leaching process of the converted product with Ca3WO6 by roasting tungsten-containing materials.
  • Leaching and recovery of phosphate and rare earth elements from an
           iron-rich fluorapatite concentrate: Part II: Selective leaching of calcium
           and phosphate and acid baking of the residue
    • Abstract: Publication date: Available online 30 December 2018Source: HydrometallurgyAuthor(s): Faraz Soltani, Mahmoud Abdollahy, Jochen Petersen, Rahul Ram, S.M. Javad Koleini, Davood Moradkhani Apatite concentrate is an important source of phosphate and contains significant amounts of rare earth elements (REEs). In this study, the possibility of selective phosphoric acid leaching of phosphate and calcium from the Esfordi (Yazd province, Iran) apatite concentrate, containing 16.3% phosphorus, 37.1% calcium, 2.9% iron and 1.2% REEs was investigated. REEs concentrated in the leaching residue were processed using acid baking and bicarbonate precipitation methods. In the phosphoric acid leaching process, almost all the Ca and phosphate of the concentrate were leached from the concentrate, whereas only about 1% of the REEs were leached. By leaching the concentrate with 25% phosphoric acid at 90 °C and 1200 rpm, a residue containing 17.5% REEs, 4.8% phosphorus and 28.5% iron was obtained. The residue was acid baked, water leached and processed for removal of iron and recovery of REEs. Acid baking at 270 °C with acid to solid ratio of 2 (w/w) for 5 h led to 95% leaching of REEs. By increasing the pH of the leachate to 3.9, all the iron and phosphate were precipitated within 2 h. Finally, REEs were precipitated from the iron-free solution by using the bicarbonate precipitation method, and a product containing 39% of total REEs was produced. The results demonstrate that the three-stage process is an elegant method for processing of the Esfordi concentrate to produce phosphoric acid and an iron-free REE carbonate concentrate.Graphical abstractUnlabelled Image
  • The effect of ore mineralogy on the electrochemical gold dissolution
           behavior in various cyanide and oxygen concentrations: Part I. Effect of
           sulfidic ores containing heavy metals
    • Abstract: Publication date: Available online 30 December 2018Source: HydrometallurgyAuthor(s): Rina Kim, Ahmad Ghahreman The effect of heavy metals-containing gold ore mineralogy on gold oxidation kinetics in solutions with various free cyanide (CN) and dissolved oxygen (DO) concentrations was studied by electrochemical tests. To effectively simulate the cyanide gold leaching conditions, the electrochemical experiments were carried out in the slurries of the ores. The results of the linear sweep voltammetry tests showed three significant gold oxidation peaks. The peak potentials and the corresponding current densities were dependent on the composition of the ores in the test slurries, and the CN and DO concentrations of the test solutions. The heavy metal concentration of the ores also effectively changed the electrochemical response of the tests.The highest gold oxidation kinetics were observed in a pyritic sample with 1800 ppm Pb, 640 ppm Ag and 195 ppm Hg (sample 1). The fastest gold oxidation kinetics were registered at −0.2 V vs. Ag/AgCl when DO was 8.3 mg/L, and the corresponding Au oxidation peak current densities were 4.75 and 7.07 mA/cm2 at 600 and 900 mg/L free CN, respectively. The Au oxidation was assisted by cementation reaction between the aqueous Hg and/or Ag species, and metallic gold. The weak lead deposition was also observed. However, the positive effect of Hg on the gold oxidation kinetics was depressed at higher DO (37.0 mg/L) concentrations. Unlike Hg, the effect of Ag on increasing the gold oxidation kinetics was shown to be independent of the solution DO.The second sample of the study, sample 2, was a sulfidic gold ore with 0.25% galena (PbS). The results showed that the presence of galena in an electrochemical gold oxidation test could increase the gold oxidation kinetics. In tests with 8.3 mg/L DO, the current densities of 2.80 and 5.23 mA/cm2 at 600 and 900 mg/L CN solutions, respectively, were obtained at −0.4 V vs. Ag/AgCl. Increasing DO to 37.0 mg/L did not improve the gold oxidation kinetics.Based on the results of this study, the presence of the specified heavy metals is most effective in gold oxidation kinetics if the free CN concentration is high and the DO concentration is low. Besides, the electrochemical methodology introduced in this study could offer a solution for determining the leaching parameters.
  • Recovery of lithium in seawater using a titanium intercalated lithium
           manganese oxide composite
    • Abstract: Publication date: Available online 26 December 2018Source: HydrometallurgyAuthor(s): Taegong Ryu, Junho Shin, Seyed Majid Ghoreishian, Kang-Sup Chung, Yun Suk Huh In this study, recovery of lithium in seawater using a titanium-intercalated lithium manganese oxide composite (LTMO) was investigated along with its adsorption capacity and durability. To minimize manganese dissolution during the extraction of Li+ by acidic treatment, a spinel type of LTMO was synthesized by the high-energy milling of a titania (TiO2), lithium carbonate (Li2CO3), and manganese carbonate (MnCO3) mixture and subsequent heat treatment. X-ray diffraction and thermogravimetric analyzer confirmed that Ti was well intercalated into the spinel structure of lithium manganese oxide (LMO). The effects of calcination temperature and Ti content on LTMO structure, lithium uptake, and adsorbent stability were investigated. Kinetic analysis showed that adsorption by LTMO followed pseudo-second-order kinetics, with a correlation coefficient in excess of 0.99. Adsorption by LTMO fitted the Langmuir isotherm well, with a correlation coefficient higher than 0.99, and LTMO exhibited higher theoretical maximum adsorption capacity than LMO (up to 21.9 mg g−1 vs. 19.6 mg g−1). In addition, LTMO showed high selectivity for lithium ions in the presence of competitive cations.
  • Oxidative precipitation of cerium in acidic chloride solutions: part I –
           Fundamentals and thermodynamics
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): James McNeice, Rina Kim, Ahmad Ghahreman Cerium, the most abundant rare earth element (REE), is typically the largest component of the hard rock REE ores. Demand for less prevalent REE, such as neodymium and dysprosium, have led to a market saturation and price collapse of cerium. One method of improving the economics of REE processing operations is to effectively remove cerium from the solution prior to SX. This is accomplished by the oxidation of Ce (III) to Ce (IV), which precipitates as cerium hydroxides. This study probes the efficacy of four oxidants for oxidative cerium precipitation from chloride solutions: hydrogen peroxide, sodium hypochlorite, potassium permanganate, and Caro's Acid. Cerium oxidation was tested using these oxidants at varying stoichiometry, a pH range of 1.0 to 4.0, temperatures of 25, 45, and 65 °C, and varying cerium concentrations. Kinetic constants were calculated from time sampled data. Complete cerium removal is achievable using potassium permanganate and Caro's acid in the absence of other REE. Thermodynamic data was used to create theoretical speciation and pourbaix plots illustrating the conditions in which cerium was oxidized using these reagents.
  • Oxygen evolution and corrosion behavior of Pb-CeO2 anodes in
           sulfuric acid solution
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): Wenjun Wang, Zhuoran Wang, Tiechui Yuan, Ruidi Li, Haihua Li, Wenjun Lin, Dan Zheng Pb-CeO2 composite anodes with different CeO2 contents were prepared by a powder metallurgy method. For comparison, pure Pb and PbAg (0.8 wt%) anodes were also prepared as references by melt casting. The oxygen evolution and corrosion behaviors of the anodes were evaluated by performing measurements of galvanostatic polarizations, Tafel curves, anodic polarization curves, mass increments, and ion concentrations. The morphologies and phase compositions of the anode oxidation layers after polarization were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results showed that as the content of CeO2 increased, the stabilized potential of the composite anodes gradually decreased; the Pb-CeO2 (>1.5 wt%) composite anode exhibited lower stabilized potential and higher electrocatalytic activity than the PbAg anode during galvanostatic polarization. The Pb-CeO2 (>0.5 wt%) composite anode showed better corrosion resistance than the pure Pb and PbAg (0.8 wt%) anode. The increase in CeO2 content improves the compactness and thickness of the oxide layer formed on the anode surface, but excess CeO2 leads to high porosity of the anode, thus deteriorating the performance. The Pb-CeO2 (2.5 wt%) anode showed comprehensively improved electrochemical performance and corrosion resistance.
  • Effect of structure of aromatic ethers on their extraction of Au(III) from
           acidic chloride media
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): Tatsuya Oshima, Takashi Horiuchi, Kiyoharu Matsuzaki, Kaoru Ohe An aromatic ethereal compound, 1-methoxy-2-octoxybenzene, was recently found to be a good extractant for Au(III) from hydrochloric acid media. The present study therefore investigated the structural factors of ethereal compounds for the extraction of Au(III) under dilute extractant concentrations. In the series of aromatic ethereal compounds used in this study, 1-dodecoxybenzene showed the highest extractability for Au(III). There was a clear correlation between the extractability of Au(III) and the strength of hydrophobicity of the aromatic ethereal compounds. Au(III) was selectively extracted using 1-dodecoxybenzene over other precious- and base-metal cations. Au(III) was quantitatively stripped from this extractant using aqueous thiourea solution.
  • Electrochemical study of silver telluride (Ag2Te): anodic and cathodic
           potential dependent-reactions in alkaline cyanide solutions
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): A.A. González-Ibarra, F. Nava-Alonso, A. Uribe-Salas Although electrochemical characterization has been used to elucidate the species formed during hydrometallurgical processes, it has not been commonly applied to the cyanidation of precious metal tellurides. In this study, voltammetric characterization of the silver telluride (Ag2Te) reaction system in alkaline cyanide solutions (pH 10.9 and 1250 mg/L CN−) was carried out making use of carbon paste electrodes. For this purpose, the electrochemical reactions system of elemental silver and elemental tellurium were first studied by cyclic voltammetry in two aqueous media (i.e., aqueous solution at pH 10.9, and 1250 mg/L CN− at pH 10.9) and, by comparing the cyclic voltammograms obtained with those for Ag2Te, the electrochemical reaction system was elucidated. The results obtained showed that the anodic oxidation of Ag2Te in alkaline cyanide solutions occurred by at least two consecutive steps according to:Step 1 (fast reaction): Ag2Te + 4CN− ↔ Te + 2Ag(CN)2− + 2e−.Step 2 (slow reaction): Te + 3H2O ↔ TeO32− + 6H+ + 4e−while the cathodic reduction of Ag2Te in alkaline cyanide solutions occurred according to:Ag2Te+2e−↔2Ag+Te2−
  • Continuous solvent extraction operations for the separation of W and Mo in
           high concentrations from ammonium solutions with acidified N1923
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): Zhihua Li, Guiqing Zhang, Li Zeng, Wenjuan Guan, Liansheng Xiao, Qinggang Li, Zuoying Cao, Xiuyuan Lu To separate tungsten and molybdenum from the ammonium solution containing 31.2 g/L WO3 and 32.5 g/L Mo, the continuous operations of solvent extraction were carried out using acidified primary amine extractant of N1923 in mixer-settlers. Thermodynamic analysis of the WMoH2O system showed that W(VI) could be selectively extracted over Mo (VI) by primary amine since WO42− was preferentially transformed to polymeric ions as the pH decrease. The results of 58 h continuous operations indicated that the solvent extraction process could be used effectively to separate W(VI) from ammonium molybdate solutions. The raffinate contained only 6.0–7.0 mg/L WO3 with a mass ratio of WO3/Mo less than 3.45–4.99×10−4, which can be used to produce ammonium molybdate with MSA-0 grade of Chinese National Standards. Compared with traditional methods on separation of W and Mo, the new process exhibited obvious advantages of low cost, high separation factor of W/Mo, environmental friendliness, which is expected to make good economic and social benefits.
  • Solvent extraction of copper from acidic chloride solutions with LIX 84
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): M.P. Elizalde, M.S. Rúa, B. Menoyo, A. Ocio The extraction equilibria of Cu(II) from HCl and HCl-KCl solutions at different ionic strengths (0.05–0.50 mol/L) by LIX 84 in toluene is reported. Copper speciation in the aqueous solutions has been previously calculated using the Specific Interaction Theory (SIT) for the calculation of the activity coefficients. The effect of the concentrations of extractant, H+ and Cl− has been examined. Graphical and numerical treatments of the experimental extraction data indicate the extraction of a single complex of stoichiometry CuL2, HL being 2-hydroxy-5-nonylacetophenone oxime, the active component of LIX 84. EPR measurements of the organic extracts have confirmed the proposed stoichiometry. The copper extraction constant values at 0.05, 0.10, 0.25 and 0.50 mol/L HCl and at 0.50 mol/L (H+,K+)Cl− have been determined and successfully correlated with the ionic strength based on the previously developed aqueous phase chemical model. The value of the copper extraction constant at infinite dilution is also reported.
  • An integrated approach to evaluating the effect of associated minerals on
           copper ammoniacal thiosulfate leaching of a gold–bearing sulfide
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): José A. Tamayo, Angel M. Meléndez, Jorge A. Calderón This work proposes a method for the evaluation of the effect of galvanic interactions between intergrown sulfide-mineral grains present in a thiosulfate leaching system, based on a combination of electrochemical measurements. Several common associated minerals in complex sulfide ore (CSO), as well as high purity sulfide minerals (pyrite, arsenopyrite, chalcopyrite, sphalerite, and galena), were used to develop and test the method. The reactivity of the CSO and each individual sulfide mineral in an ammoniacal thiosulfate solution was determined by voltammetry and chronoamperometry, using carbon paste electrodes and rotating disk electrodes (RDE). Secondary phase formation and the surface alteration of both the individual and associated minerals were evaluated by in-situ Raman spectroscopy and ex-situ cyclic voltammetry in 0.1 M NaNO3 aqueous solution. Chalcocite (Cu2S) and covellite (CuS) were identified as intermediate products of chalcopyrite leaching, while pyrite was oxidized to ferrous hydroxide and later to magnetite. Results showed that pyrite in CSO acts as a cathodic side, promoting the reduction of oxygen. Thus, the oxidation of pyrite was delayed due to the galvanic protection offered by arsenopyrite and chalcopyrite. Mineralogy and evaluation of the mineral textures both of the ore and its modification as a result of leaching were used to validate the method.Graphical abstractUnlabelled Image
  • The electrochemistry and kinetics of the oxidative dissolution of
           chalcopyrite in ammoniacal solutions. Part II – Cathodic reactions
    • Abstract: Publication date: Available online 21 December 2018Source: HydrometallurgyAuthor(s): T. Moyo, J. Petersen, M.J. Nicol The cathodic reduction of copper(II) and oxygen on the surface of chalcopyrite have been studied in ammonia-ammonium sulphate using cyclic voltammetry and chrono-amperometry. The predominant cathodic reaction in the oxidative dissolution of chalcopyrite in ammoniacal solutions has been established to be that of the reduction of copper (II). The rate of the cathodic reaction is inversely dependent on the total ammonia concentration and although the tetra-ammine copper(II) ion is the most dominant species under these conditions, it is suggested that the tri-ammine complex is the most electroactive under these conditions. It was shown that both the reduction of copper(II) and oxidation of copper(I) occur simultaneously at potentials close to the mixed potentials of chalcopyrite under the conditions of this study and apparent mass transfer limitations observed on the reaction were concluded to be due the outward migration of the product of Cu(I) ions from the mineral surface.
  • Desilication of concentrated alkali solution by novel desilication reagent
           calcium hydroferrocarbonate: Part II. Desilication reaction and kinetics
    • Abstract: Publication date: Available online 18 December 2018Source: HydrometallurgyAuthor(s): Tao Hong, Jun Luo, Manbo Liu, Shili Zheng, Yi Zhang Using a hydroferite desilication reagent, calcium hydroferrocarbonate (CHFC), the desilication reaction in concentrated caustic aluminate solution was studied. The results indicated that process parameters, such as temperature, Na2O concentration, molar ratio of Na2O to Al2O3, and initial mass ratio of alumina to silica (mass ratio of alumina to silica), significantly affected the reaction efficiency. The reaction kinetics were found to exhibit a reaction order of 1.3 ± 0.15 for desilication; the empirical rate constant k was 64.4 ± 2.4 and the apparent activation energy Ea was 25.8 ± 3.2 kJ/Mol, which was much lower than the values obtained by adding Ca(OH)2, C3AH6(calcium Hydroaluminate, 3CaO·A12O3·CaCl2·6H2O), and Friedel's salt (3CaO·A12O3·CaCl2·10H2O). In the desilication process, silica reacts with CHFC on the surface to form hydroandradite and calcium aluminum iron hydroxide. Subsequently, with an increase in Na2O concentration and temperature, hydroandradite and calcium aluminum iron hydroxide dehydrated to form calcium aluminum iron silicate and Fe(OH)3
  • Purification of high iron wet-process phosphoric acid via oxalate
           precipitation method
    • Abstract: Publication date: Available online 17 December 2018Source: HydrometallurgyAuthor(s): H.M. Abdel-Ghafar, E.A. Abdel-Aal, M.A.M. Ibrahim, H. El-Shall, A.K. Ismail A method has been developed to reduce the iron content in phosphoric acid produced by the dihydrate wet process from open cast phosphate rock of Abu-Tartur mine in Egypt. In this method, oxalic acid was used to precipitate iron as ferrous oxalate dihydrate (FeC2O4.2H2O). The achieved removal efficiency of iron was about 91% due to the low solubility of the precipitated salt in dilute phosphoric acid medium. The maximum P2O5 losses were less than 1.0%. The optimum conditions of oxalate precipitation method were obtained using synthetic dilute phosphoric acid (28% P2O5, 390 g/L H3PO4) with iron content amounting 2.8% (w/w) Fe2O3 (26.3 g/L Fe). It was found that, the clarification time, reaction temperature, P2O5 concentration and oxalic acid dose were 2 h, 60 °C, 28% P2O5 and 7.5 g oxalic acid/100 g 28% P2O5 acid, respectively. These conditions were applied using wet-process phosphoric acid (26% P2O5). Firstly, ferric ions in the acid were reduced to ferrous ions using iron scrap, followed by oxalic acid addition. Mostly all iron ions in the solution are in the divalent state at Electro Motive Force (EMF) values less than 275 mV. The solubility of ferrous oxalate dihydrate was measured at different temperatures and phosphoric acid concentrations. A recovery study for oxalic acid from the precipitated FeC2O4.2H2O has performed.
  • Comparison of arsenic(V) removal with different lead-containing substances
           and process optimization in aqueous chloride solution
    • Abstract: Publication date: Available online 12 December 2018Source: HydrometallurgyAuthor(s): Hua Long, Ya-jie Zheng, Ying-lin Peng, Gui-zhong Jin, Wei-hua Deng, Shou-chun Zhang In this study, the removal effect of arsenic(V) was compared with different lead-containing substances, and the process of arsenic(V) removal with lead oxide was optimized. The results showed that As(V) removal efficiencies with lead powder, lead oxide, lead hydroxide and lead nitrate were 26.5%,> 99.9%, 98.5% and 96.3% at lead/arsenic(Pb/As) molar ratio of 2.12, respectively. Arsenic(V) removal with lead and its compounds was mainly based on the formation of mimetite. The removal of arsenic with lead oxide did not introduce impurity anions, and the crystallization performance and stability of the precipitate were relatively better than those of the precipitates obtained with other lead-containing substances. The crystallization performance of the precipitate was obviously improved when lead oxide was added twice. Using pH-conditioning in the process of arsenic removal, the residual lead in the solution could be removed via the co-precipitation of the hydrolysis of Pb2+ with mimetite. The highest As(V) leaching concentration of As—Pb precipitates was 0.2 mg/L at the pH of 1.9–12.3 with the leaching time of 1–48 h, and the stability of As—Pb precipitates could be improved by washing with dilute nitric acid. Lead oxide could be used as an effective reagent of arsenic removal in aqueous chloride solution.
  • Recovery of Th(IV) from leaching solutions of rare earth residues using a
           synergistic solvent extraction system consisting of Cyanex 572 and n-octyl
           diphenyl phosphate (ODP)
    • Abstract: Publication date: Available online 12 December 2018Source: HydrometallurgyAuthor(s): Haiyue Zhou, Yamin Dong, Yabin Wang, Zeyuan Zhao, Yu Xiao, Xiaoqi Sun The synergistic effect of mixed Cyanex 572 and n-octyl diphenyl phosphate for Th(IV) extraction from nitric acid solution has been investigated in this paper. The effect of acidity together with mole fraction of extractant on the synergistic effect was studied. Based on the obtained results, the maximal synergistic enhancement coefficient reaches 12.40 at a ratio of 1:2 of Cyanex 572 and n-octyl diphenyl phosphate. Under the experimental conditions, the phase separation performance, stripping property and selectivity of Th and REE in the mixed extraction system are better than those from individual Cyanex 572 or n-octyl diphenyl phosphate system. The synergistic extraction mechanism for Th(IV) in nitric acid medium is proposed as Thaq4++HA2org+2.5Borg+3NO3−aq↔KexThNO33HA2B2.5org+Haq+. The mixed extraction system is successfully used for the separation of Th(IV) and REE(III) from the industrial feed solution leached from ion-absorbed type rare earth mineral waste residue. Lower stripping acid, stronger extraction ability, better phase separation performance and selectivity provide the synergistic extraction system with good application prospects.Graphical abstractUnlabelled Image
  • Kinetics and mechanism of the reduction-dissolution of cerium oxide
           catalyzed by fluoride ions in hydrochloric acid solution
    • Abstract: Publication date: Available online 12 December 2018Source: HydrometallurgyAuthor(s): Florent Lemont, Alizée Barbier The dissolution of cerium oxide in aqueous solutions is hindered by the stability of the crystalline network. This reaction can however be catalyzed by fluoride ions and we show here using several metallic fluorides that the cation does not affect the reaction rates and that only the fluoride ions, present as HF under strongly acidic conditions, have a catalytic effect. The dissolution process is shown to consist of two main stages, the first involving the release of Ce4+ ions into the solution under the effect of the fluoride ions, the second, the reduction of the Ce4+ ions by the chloride ions. The experiments show that the first stage of the reaction obeys first order kinetics, the fluoride atoms acting as nucleophiles that replace surface hydroxide functions originating from the superficial protonation of CeO2. The Ce4+ ions are then released as stable CeF22+ complexes. The overall dissolution-reduction mechanism for cerium oxide that we propose on the basis of these results involves first stage on the surface of the grains and a second in the body of the solution.
  • Inter-particle liquid spread pertaining to heap leaching using UV
           fluorescence based image analysis
    • Abstract: Publication date: Available online 10 December 2018Source: HydrometallurgyAuthor(s): I.M.S.K. Ilankoon, S.J. Neethling The visualisation of individual flow paths in a porous media and how they relate to the overall hydrodynamics is crucial to improving our understanding of a number of systems. Unsaturated flow through larger particles (order of millimetres and few centimetres) in heap leaching systems where both gravity and capillarity play an important role in the structure of the flow paths is complex and still not fully understood. A variety of laboratory methods have been employed for this purpose, with UV light being used in several studies. Flow studies have typically involved millimetre and sub-millimetre scale particles and the flow is typically capillary-dominated. This paper instead concentrates on gravity-dominated flows pertaining to heap leaching and is particularly focused on developing methods for using the UV fluorescence to obtain quantitative measurements of liquid spreading, such as average lateral liquid spread for a point source liquid addition. This study uses a pseudo-2D system with larger ore particles than in previous UV flow studies. UV fluorescence results were analysed using image analysis to determine the overall liquid spreading and the locations of the flow paths. Both narrowly sized and realistic ore systems were investigated to understand the effect of length scale on flow paths and dynamics of liquid spreading through the gravity-dominated ore beds. It was shown that both ore systems experience distinct flow channelling compared to the more uniform flow profiles observed in capillary-dominated systems. Lateral liquid spreading coefficients were calculated, with the narrowly sized ore system showing higher values, probably due to the larger effective length scale of the inter-particle spaces.Graphical abstractUnlabelled Image
  • Effect of microwave heating on the pressure leaching of vanadium from
           converter slag
    • Abstract: Publication date: Available online 8 December 2018Source: HydrometallurgyAuthor(s): Lei Tian, Zhifeng Xu, Lijie Chen, Yan Liu, Ting-an Zhang In this paper, a comparison is made between the leaching associated with microwave heating (MHL) and electric heating (EHL) of converter vanadium slag in an autoclave under an oxygen pressure of 0.4 MPa. The comparative study of the leaching processes showed that the vanadium leaching efficiency reached 46% in 20 min using EHL, whereas it reached 96% under the same condition when MHL was used. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses of MHL residue showed that decomposition of the spinel phase in the converter vanadium slag can be accelerated through this process. In addition, MHL can reduce the granularity and make the surface of the particles more porous. In general, using MHL is more effective than EHL, for the leaching of converter vanadium slag in pressure leaching process. Through kinetic studies of MHL and EHL, the activation energies of vanadium leaching were determined to be 14.8 and 40.5 kJ/mol, respectively. The reaction rate depends on acid concentration as well as oxygen partial pressure. The order of reaction with respect to H2SO4 concentration was found to be 0.99 for MHL and 2.21 for EHL. The order of reaction with respect to the oxygen partial pressure was found to be 0.51 and 0.65 for MHL and EHL, respectively. The kinetic equations are derived and reported for MHL and EHL processes.
  • Degradation of hydroxyoxime extractants by nitration and remedies with
           inhibitor reagent
    • Abstract: Publication date: January 2019Source: Hydrometallurgy, Volume 183Author(s): Zhi-gang Xu, Tao Zhou, Qian Zou, Yong-xi Wang, Chao-hua Wang, Dong-mei Zhang, Fei Wang In this study, degradation of hydroxyoxime extractants by nitration was studied in nitrate media. The effect of nitrate concentration in the range of 10–40 g/L, pH value range of 1.5–2.3, temperature in the range of 25–35 °C and different modifiers including 2,2,4-trimethylpentanediol diisobutyrate, tridecyl alcohol and nonyl phenol on the nitration of hydroxyoxime extractants was investigated. A new type of inhibitor reagent consisted of tertiary butylhydroquinone (TBHQ) and styrolfenol blend (1:2, w/w) was investigated in a nitrate media under 180 g/L H2SO4 at 30 °∁ for required time. It is shown that the new inhibitor reagent (3%, w/w) can reduce the nitration to half for hydroxyoxime extractants. In addition, other measures such as increasing the pH to above 2.3, using more stable reagents like ketoximes, to reduce nitration were suggested.
  • Recovery of rhenium from aqueous mixed metal solutions by selective
           precipitation: A photochemical approach
    • Abstract: Publication date: Available online 5 December 2018Source: HydrometallurgyAuthor(s): Hisao Hori, Takafumi Otsu, Takahiko Yasukawa, Rin Morita, Shota Ishii, Takuma Asai Selective precipitation recovery of rhenium from aqueous solutions containing a coexisting metal (molybdenum, tungsten, or aluminum) by means of UV–visible light irradiation in the presence of 2-propanol and acetone was investigated. When the pH of the rhenium–molybdenum solutions (initial concentration 10.4 mM for each metal) was in the range from 6.3 to 12.5 and the irradiation time was 6 h, the rhenium in the initial solutions was efficiently recovered in the precipitates (92–99%), and the rhenium selectivity was high (the rhenium recovery ratio was 9.2–21 times that of molybdenum). The high selectivity for rhenium was also observed at different molybdenum concentrations (4.8–15.7 mM) and at a higher rhenium concentration (17.5 mM).Rhenium was also recovered efficiently and selectively from rhenium–tungsten solutions (initial concentration 10.4 mM for each metal): when the pH ranged from 7.0 to 12.0 and the irradiation time was 6 h, the rhenium recovery was 90–95% and the rhenium recovery ratio was 7.3–45 times that of tungsten. In contrast, when the coexisting metal was aluminum (initial rhenium and aluminum concentrations, 10.4 mM and 8.6 mM, respectively; pH 11.2), 95% of the rhenium was recovered in the precipitate after 6 h of irradiation; however, aluminum was somewhat unstable in the basic solution and the rhenium recovery ratio was 3.2 times that of aluminum. Unlike molybdenum and tungsten, aluminum tended to coprecipitate with rhenium.
  • The effect of silver on the acidic ferric sulfate leaching of primary
           copper sulfides under recycle solution conditions observed in heap
           leaching. Part 3: Surface characterization
    • Abstract: Publication date: Available online 3 December 2018Source: HydrometallurgyAuthor(s): Tendekayi Tapera, Aleksandar N. Nikoloski The surface products formed on chalcopyrite during leaching in sulfate solutions in the presence of various additives were investigated. A combination of SEM, EDS, TEM, FIB and XRD was used to characterize the surface products formed under different leaching conditions. The influence of additives such as ethylene glycol, wetting agent and chloride ions, in both the presence and absence of silver ions, on the type of surface products formed was investigated. In the presence of both silver ions and ethylene glycol, metallic silver in the form of nanoparticles was formed and deposited on the surface. The silver nanoparticles were predominantly cubic in shape and had varying dimensions up to 500 nm. The metallic silver formation is aided by the reduction of silver ions with ethylene glycol in the sulfate media. The deposition of metallic silver on the chalcopyrite surface in turn enhances the leaching of the chalcopyrite by improving the surface conductivity. In the presence of low dosages of chloride ions, large quantities of elemental sulfur were formed. Increasing the concentration of chloride ions reduced the extent of sulfur formation. The elemental sulfur formed in the presence of chloride ions was found to be porous. In the presence of a wetting agent, the formation of elemental sulfur was again observed, both in the presence and absence of silver, but its influence on the leaching process may be less.
  • Precipitation of monosodium aluminate hydrate from concentrated sodium
           aluminate solution
    • Abstract: Publication date: Available online 3 December 2018Source: HydrometallurgyAuthor(s): Shaowei You, Tao Guo, Pengfei Liu, Xiang Mao, Yifei Zhang Precipitation of monosodium aluminate hydrate (MAH) from concentrated sodium aluminate solution in the hydro-chemical process of alumina production was carried out in a continuously operated crystallizer. Crystal size distribution and morphology of MAH crystals were greatly influenced by parameters in the crystallization process, including mean residence time, supersaturation, temperature and agitation. Spherical MAH crystals with uniform size were successfully obtained. A condition of the mean residence time of 50 min, the temperature of 60 °C, the supersaturation of 5.3 and the agitation speed of 300 rpm was preferred in the precipitation of MAH crystals.
  • Application of citric acid as eluting medium for titanium type lithium ion
    • Abstract: Publication date: Available online 3 December 2018Source: HydrometallurgyAuthor(s): Shulei Wang, Min Zhang, Ying Zhang, Yang Zhang, Shan Qiao, Shili Zheng The titanium type lithium ion sieve (Ti-LIS) is usually considered as a promising lithium ion sieve (LIS) by the virtue of its superiorities in both stable structure and high adsorption capacity. Acidification process is a significant and necessary step for LIS application in the lithium adsorption from brine, which has raised two problems including partly dissolution of the Ti-LIS structure and the low lithium ions enrichment in elution solutions. Many reported works about the Ti-LIS focused on reducing the amount of loss of Ti-LIS but ignored the lithium ions enrichment in elution solutions. In this manuscript, an effective strategy that employing a proper weak polyprotic acid to replace the most widely eluting medium of hydrochloric acid was proposed, and the citric acid was selected on the basis of its superior properties containing low damage to the structure of Ti-LIS (titanium loss ≤0.05%) and high lithium ions concentration enrichment (4.06 g L−1) with 0.2 mol L−1 in elution solutions. Meanwhile, the adsorption performance of Ti-LIS treated with citric acid was also investigated by batch experiments, and the results revealed the adsorptive ability of the Ti-LIS could reach up to 52 mg g−1 in LiOH solutions (1.8 g L−1 Li, pH 12). Furthermore, the competitive absorbing and recycling results demonstrated that the Ti-LIS treated with citric acid still has a remarkable selectivity to Li+ and stable adsorptive function. Consequently, it elucidated that the citric acid was an effective eluting medium in the application of LIS.Graphical abstractUnlabelled Image
  • Cr(III) and Fe(II) recovery from the polymetallic leach solution of
           electroplating sludge by Cr(III)-Fe(III) coprecipitation on maghemite
    • Abstract: Publication date: Available online 29 November 2018Source: HydrometallurgyAuthor(s): Tong Yue, Zhen Niu, Yuehua Hu, Haisheng Han, Deliang Lyu, Wei Sun The separation of Cr(III) from the polymetallic leaching solution is a typical problem encountered during the recycling of electroplating sludge. In this paper, a novel method was proposed to recover Cr(III) and Fe(II) synchronously by forming the Cr(III)-Fe(III) coprecipitates on the surface of maghemite (γ-Fe2O3) fine particles with Fe2(SO4)3 solution as the supplemental Fe source. The results showed that high Fe(III) to Cr(III) ratio in solution promoted the hydrolysis and precipitation of Cr(III). In addition, the maghemite particles, served as the crystal nuclei, could induce the formation of the core-shell structured Cr(III)-Fe(III) coprecipitates on its surface and accelerate the sedimentation of the coprecipitates in the magnetic field. By using a two-stage Cr(III)-Fe(III) coprecipitation process, the recoveries of Cr and Fe reached 96.17% and 99.39%, and the grades of Ni, Cu, and Zn in the coprecipitates were at 0.41%, 0.38%, and 0.22%, respectively. The obtained coprecipitates can be recycled as the feed material of chromium smelting after heat treatment. This method is simple and efficient for high-concentration Cr3+ solution treatment, which is beneficial for the sustainable development of resources and environment.Graphical abstractUnlabelled Image
  • Chemical, morphological, and kinetic study of lead extraction from the
           Koni Mansur polymetallic deposit
    • Abstract: Publication date: Available online 28 November 2018Source: HydrometallurgyAuthor(s): Golibsho Nasymov, Zumrat Gaibullaeva, Nuran Ay, Alevtina Smirnova Located in the north of Tajikistan, the Koni Mansur is a rich polymetallic deposit that besides other metals has high concentration of lead-containing mineral galena. The hydro metallurgical extraction of lead from the Koni Mansur lead sulfide (galena) mineral in acidic media, its chemical composition and morphological properties in comparison to the Balya deposit in Turkey are reported for the first time. Energy dispersive X-ray fluorescence spectrometry was applied for chemical analysis of galena, while mineralogical characterization before and after lead acidic extraction was performed by XRD. The nitric acid concentration, temperature, duration of the extraction process, and the particle size distribution before and after extraction have been evaluated. The amount of lead in solution after extraction and solid-liquid phase separation was determined by the flame atomic absorption spectroscopy (FAAS). The particle size distribution before and after lead extraction revealed no significant changes. Assuming spherical shape of the particles, the Shrinking Core Model (SCM) used for kinetic study of the lead extraction allowed to define the activation energies and changes in the corresponding reaction mechanisms. Specifically, the activation energy at 293-318 K (12.4 kJ/mol) was significantly lower than at higher temperatures (318–338 K) reaching ~46.778 kJ/mol which indicates the corresponding change in the extraction mechanism.
  • A parameters study of the novel atmospheric pyrite oxidation process with
           Lewatit® AF 5 catalyst
    • Abstract: Publication date: January 2019Source: Hydrometallurgy, Volume 183Author(s): Denver H. Cowan, Fazel G. Jahromi, Ahmad Ghahreman A previous study conducted by the authors introduced a novel process for atmospheric pyrite oxidation with Lewatit® AF 5, a micro/mesoporous carbonaceous bead. This paper presents a parameters study of the atmospheric oxidation of the AF 5 catalysed pyrite oxidation process, promoting maximum pyrite oxidation and maximizing the elemental sulphur generation. Tests were conducted in 2 L jacketed reactors with controlled conditions. The study consisted of multiple tests investigating the effect of temperature (75, 80, 85 and 90 °C), initial sulphuric acid concentration (0.25, 0.5 and 1.0 M), initial ferric concentration (0, 1, 5 and 10 g/L), pyrite concentrate to catalyst mass ratio (4:1, 2:1, 1:1 and 1:2), and test slurry solid pulp density (5, 10 and 20 wt%) on the atmospheric leaching of a pyrite concentrate assisted by AF 5. The study indicated that the most effective parameters in the pyrite oxidation are the test temperature and concentrate to catalyst mass ratio. The best tests in terms of overall pyrite oxidation and elemental sulphur production were those with a 1:2 concentrate to catalyst ratio at 90 °C. These tests had an average of 96.2% overall pyrite oxidation and an elemental sulphur yield on average of 51.0%. Increasing temperature from 75 to 90 °C improved overall pyrite oxidation from 71.9 to 93.6%, however elemental sulphur yields of approximately 46.3% were experienced at temperatures below 90 °C versus 43.3% at 90 °C. Other trends experienced in the investigation of the various parameters will be further discussed.
  • Separation of indium from impurities in T-type microreactor with D2EHPA
    • Abstract: Publication date: January 2019Source: Hydrometallurgy, Volume 183Author(s): Thiquynhxuan Le, Biquan Xiao, Shaohua Ju, Jinhui Peng, Feng Jiang The extraction efficiencies and separation factors (βIn/Fe, βIn/Zn, βIn/Al, βIn/Mg) of indium and impurities (Fe3+, Zn2+, Al3+, Mg2+) are compared with the different extractant concentration, initial pH and contact time during microfluidic extraction and conventional extraction. The results show that the optimal experimental conditions for microfluidic extraction are pH value of 0.7, extractant concentration of 30%, contact time of 60 s. compared to conventional extraction, microfluidic extraction can reduce the contact time by half, and effectively improve the separation factor of indium and impurities. βIn/Fe increased from 276 in conventional extraction to 18,720 in microfluidic extraction, βIn/Zn increased from 70,118 to 266,373, βIn/Al increased from 4987 to 41,955, and βIn/Mg increased from 2918 to 11,809. The effect of iron on the extraction efficiency of indium is higher than that of zinc, aluminum and magnesium. In addition, the efficient selective extraction of microreactor was explained by comparing the flow forms of the fluids in the conventional and microfluidic extraction methods.
  • A lithium selective adsorption composite by coating adsorbent on PVC plate
           using epoxy-silica hybrid binder
    • Abstract: Publication date: Available online 27 November 2018Source: HydrometallurgyAuthor(s): Taegong Ryu, Dong-Hee Lee, Jae Chun Ryu, Junho Shin, Kang-Sup Chung, Young Ho Kim The industrial demand for lithium especially in a battery is expected to be high in near future. The use of lithium selective adsorbents, such as spinel-type lithium manganese oxides (LMOs) show the potential candidates for recovery of lithium from seawater. Here we report the approach for recovery of lithium from seawater using a new composite composed of LMO and epoxy-silica hybrid binder (HB) prepared by sol-gel method. The LMO and HB composites were coated on polyvinyl chloride (PVC) plate and its adsorption efficiency was studied in terms of binder contents and thickness. The composite showed excellent physicochemical and mechanical durability in seawater. The adsorption capacity of 6.5 mg/g (67% in comparison to that by powder LMO) was obtained in natural seawater when the composition of HB/LMO was 30/70 (in dry wt%) at a thickness of 300 μm. The kinetic study showed that the lithium adsorption on composite obtained using 30 mg/L Li spiked seawater was found to be matched to pseudo-second order model as the coating thickness was
  • Lead leaching mechanism and kinetics in electrolytic manganese anode slime
    • Abstract: Publication date: Available online 26 November 2018Source: HydrometallurgyAuthor(s): Benjun Wang, Linlin Mu, Song Guo, Yafan Bi Anode slime is produced by electrolytic manganese production enterprises. The effects of anode slime particle size, leaching temperature, leaching agent concentration, and leaching time on the extent of lead leaching were investigated using ammonium acetate as the leaching agent. The lead leaching mechanism and kinetics in the anode slime were also studied. The extent of lead leaching of anode slimes with different particle sizes is significantly different. The extent of lead leaching was increased by elevating the leaching temperature. The extent of leaching reaches 99.3% after 30 min of leaching when the average particle size of anode slime approaches 10 μm, the leaching temperature is 80 °C, and the concentration of ammonium acetate is 2 mol/L. Due to the high-temperature roasting, the high valence state of the lead is changed. Then, both the compact structure between the wrapped lead and the external anode slime and the dense structure between the coated lead and the anode mud outside are destroyed. A multidimensional tunnel and a porous network structure with cracks are formed. Under the mechanism of the complex, lead is transferred from the solid phase to the liquid phase. The lead leaching process followed the “shrinkage particle model”. The reaction is mainly controlled by the diffusion of solid product layers. The apparent activation energy of the reaction Ea (28.521 kJ/mol), the pre-exponential factor A (13.34), and the macroscopic kinetic equation are obtained by establishing a macroscopic dynamic model based on the experimental data.
  • Identification and regeneration of degradation products from phenolic
           hydroxyoxime-based extractant in long-term copper solvent extraction plant
    • Abstract: Publication date: Available online 22 November 2018Source: HydrometallurgyAuthor(s): Guoyao Li, Chun Wang, Shuiping Zhong, Hongzhen Xie, Hang Chen The phenolic hydroxyoxime-based extractant has been discovered to degrade gradually in commercial copper solvent extraction plant. The main degradation products occurred through hydrolysis rather than oxidation or Beckmann rearrangement, which were identified as 1-(2-hydroxy-5-nonylphenyl)propan-1-one and 5-nonyl salicylaldehyde through instrumental analysis. The degradation products could reduce the extraction isotherm, the stripping isotherm and the transfer of copper. Moreover, the extractant regeneration of 5-nonyl salicylaldoxime from 5-nonyl salicylaldehyde was achieved with hydroxylamine sulfate. It was observed that the copper loading capacity of regenerated extractant increased by 64%, compared to the copper loading of untreated hydroxyoxime extractant.
  • The comprehensive utilization of oxidative hydrochloric acid leaching of
           anode slime bearing fluorine, arsenic and antimony
    • Abstract: Publication date: Available online 20 November 2018Source: HydrometallurgyAuthor(s): Yanxiang Shu, Huazhen Cao, Liankui Wu, Guangya Hou, Yiping Tang, Guoqu Zheng This work presented a new strategy to comprehensive utilization of hydrochloric acid leaching solution of anode slime bearing fluorine, arsenic, and antimony. Firstly, the fluorosilicic acid and fluorosilicates in the leaching solution were removed by barium chloride. Then the arsenic and antimony in the defluorinated leaching solution were separated by distillation. Finally, AsSb alloy was electrodeposited from the electrolyte prepared with the distillates. Results show that the defluorination efficiency is 97.81% under optimum condition and the residual fluorine concentration decreases from 21.46 to 0.47 g/L. The distillation recovery of As(III) is 97.44% in the defluorinated leaching solution. AsSb alloy can be electrodeposited from the electrolyte containing 5 g/L As(III), 1 g/L Sb(III) and 4 mol/L HCl. The obtained AsSb alloy shows an amorphous structure with a composition of 84.48 wt% As and 15.52 wt% Sb. Moreover, after electrodeposition of AsSb alloy, the electrolyte can be returned to the leaching process and a closed loop for the solution treatment is achieved.Graphical abstractUnlabelled Image
  • The effect of Fe(III) concentration on the dewatering behaviour of Fe(III)
           oxyhydroxide precipitates from low-tenor solutions
    • Abstract: Publication date: Available online 19 November 2018Source: HydrometallurgyAuthor(s): Cledwyn Mangunda, Jochen Petersen, Alison Emslie Lewis The settling and dewatering of sludge are critical steps in the lime precipitation treatment of iron rich wastewaters, such as acid mine drainage (AMD). This fundamental study describes the effect of different ferric feed concentrations ([Fe(III)]: 50 to 800 mg/L) on the dewatering behaviour of the sludge precipitated under steady state conditions and high pH (9 to 11), as measured through filterability and settleability. Experiments were conducted in an agitated mixed-suspension-mixed-product-removal (MSMPR) reactor in which Fe2(SO4)3 and Ca(OH)2 were added as the Fe(III) and OH– sources, respectively, and the product was collected for analysis from the overflow. Reaction conditions were such that no gypsum was precipitated. The results indicate that the Fe(III) in the feed influenced the dewatering behaviour of the precipitation product, via particle size, particle size distribution (PSD), surface charge, morphology and structure. Particles formed at 300 mg/L exhibited increased size with a maximum D4,3 of 27 μm, a narrow PSD characterized by a span of 1.65, a specific resistance to filtration (SRF) of 1.42 × 1012 m/kg and a zeta potential of approximately 0 mV. These conditions resulted in enhanced agglomeration and better settling behaviour, although the filtering behaviour was not improved. This dewatering behaviour was attributed to a dense network of interlocked and interconnected bridges in the bulk morphology of the particles as evidenced by image analysis results. The steady state pH and Fe(III) conversion in the reactor were also influenced by the feed [Fe(III)] changes. The results show scope for potentially better solid-liquid separation in iron precipitation processes through controlling feed [Fe(III)].Graphical abstractUnlabelled Image
  • Selective extraction of zinc, gallium, and germanium from zinc refinery
           residue using two stage acid and alkaline leaching
    • Abstract: Publication date: Available online 19 November 2018Source: HydrometallurgyAuthor(s): Shuai Rao, Dongxing Wang, Zhiqiang Liu, Kuifang Zhang, Hongyang Cao, Jinzhang Tao In this research, zinc, gallium, and germanium were selectively dissolved from zinc refinery residue by stepwise leaching. The thermodynamic study demonstrated that Zn, Ga, and Ge could be selectively leached by controlling a suitable pH condition. In the first stage of leaching with sulfuric acid media,>93% of the Zn content, approximately 100% of the Ga content, and
  • Adsorption of U(VI) from eutrophic aquesous solutions in a U(VI)-P-CO3
    • Abstract: Publication date: Available online 19 November 2018Source: HydrometallurgyAuthor(s): Jun Liu, Changsong Zhao, Jing Wang, Hanyi He, Guoyuan Yuan, Huilin Wang, Jijun Yang, Jiali Liao, Yuanyou Yang, Ning Liu Hydrous titanium dioxide supported by commercially available polyacrylonitrile fiber (c-PANF/TiO2·xH2O) was synthesized via a simple blending method to first investigate its U(VI) adsorption behavior from eutrophic aqueous solution in a U(VI)-P-CO3 system. TG-DSC and XRD analysis demonstrated that the material had good structural stability during the adsorption process. The theoretical maximum U(VI) adsorption capacity (qe) of c-PANF/TiO2·xH2O calculated from the Langmuir isotherm was ~256 mg/g. However, high initial solution pH values, total dissolved carbonate concentration and ionic strength could inhibit U(VI) chemisorption. In particular, qe and sorption efficiency (S%) values were maintained at ~100 mg/g and> 80% for the [P] range of 0 to 150 μmol/L, and then they rapidly decreased once [P] exceeded 150 μmol/L due to the competitive adsorption between HPO42-/H2PO4- and uranium anionic complexes such as UO2(CO3)34−, UO2(CO3)22− and UO2PO4-. XPS analysis suggested that Ti3+ defects and OH groups on the composite surface could be the U(VI) adsorption sites. Moreover, a 0.1 mol/L H2SO4 solution was found to be the most effective desorption agent. The findings reported in this study are significant in regards to the extraction of uranium from eutrophic seawater and for the understanding of uranium adsorption behaviors in multi-carbonate systems.Graphical abstractUnlabelled Image
  • Recovery of rare earths from waste cathode ray tube (crt) phosphor powder
           by selective sulfation roasting and water leaching
    • Abstract: Publication date: Available online 19 November 2018Source: HydrometallurgyAuthor(s): Mehmet Ali Recai Önal, Koen Binnemans Until recently, most displays, such as television and computer screens, were based on cathode ray tubes (CRTs). With the introduction of new types of displays including liquid crystal displays, CRTs have been widely replaced, leading to a gradual build-up of hazardous CRT powder waste. In this paper, a new approach is introduced where the valuable rare-earth elements (REEs) (i.e. yttrium and europium) in the powder are selectively recovered, leaving behind a zinc-rich residue and glass for further recycling. The main rare-earth compound in the waste powder is Y2O2S:Eu3+ (YOS). The fine-grained CRT powder was mixed with zinc sulfate monohydrate (ZnSO4.H2O) and roasted at 600–900 °C for short periods of time. In this way, Y2O2S:Eu3+ was transformed into water-soluble rare-earth sulfates. Meanwhile, ZnS underwent a two-stage reaction with ZnSO4.H2O, where first a partially water-soluble intermediate (ZnO2ZnSO4) and then the water-insoluble ZnO was formed. Addition of a sufficient amount of ZnSO4.H2O ensured the recovery of ≥95% of the rare earths in a subsequent water leaching step, but there was also co-dissolution of about 5% of the total amount of zinc present. Several purification methods were tested and compared to separate the REEs from the zinc impurity in the solutions. In addition to the conventional precipitation methods with sulfides and oxalic acid, a novel liquid-liquid exchange reaction between REE-containing leachate and zinc-loaded Versatic Acid 10 was tested. Finally, a complete flow sheet is proposed for the (almost complete) valorization of REEs as well as the total zinc present.
  • Electrochemical behaviour of Ni3S2 and its spontaneous formation on
           metallic iron in ammoniacal-carbonate solutions
    • Abstract: Publication date: Available online 17 November 2018Source: HydrometallurgyAuthor(s): Anna D'Aloya, Gamini Senanayake, David Ralph, Aleksandar Nikoloski The oxidative dissolution of iron in ammoniacal-carbonate solutions containing nickel(II) and thiosulfate ions was found to result in the formation of a nickel sulfide layer which, based on Grazing Incidence X-Ray Diffraction (GIXRD) studies conducted on the iron surface following immersion, was found to contain Ni3S2. Consistent with this, linear sweep and rotating disk cyclic voltammetry measurements conducted with the iron electrode following immersion in these solutions resulted in the presence of an anodic peak thought to correspond to the oxidation of the nickel sulfide layer. Different concentrations and relative ratios of the ammonia and carbonate species were found to have a significant effect on both the size of this anodic peak, as well as the electrochemical behaviour of the iron during the immersion period under open circuit conditions. The results suggested that an increase in total carbonate concentration relative to the total ammonia concentration promoted the formation of the nickel sulfide layer which, in more dilute solutions than those typically encountered in industry, was in turn found to promote passivation of the iron. In order to evaluate the re-dissolution behaviour of the nickel sulfide layer following its potential formation on iron, further investigations were conducted using commercial Ni3S2, which was found to have a similar XRD pattern and electrochemical behaviour to the nickel sulfide layer formed on iron. Electrochemical studies indicated that the dissolution of Ni3S2 in ammoniacal-carbonate solutions is likely to be limited by the formation of a nickel-deficient, sulfur-rich species.
  • Enhanced acid treatment to extract lithium from lepidolite with a
           fluorine-based chemical method
    • Abstract: Publication date: Available online 14 November 2018Source: HydrometallurgyAuthor(s): Hui Guo, Ge Kuang, Hao Wan, Yi Yang, Hai-zhao Yu, Hai-dong Wang Lepidolite has recently become valued as an important lithium ore resource due to the rapidly increasing demand for lithium (Li) for lithium-ion batteries (LIBs). However, existing processes to extract Li from lepidolite are still difficult and uneconomical, since the amount of lithium contained is typically low. Here, a fluorine-based chemical method was proposed to enhance the lithium extraction and utilize the 2–4% F from lepidolite. Additionally, a mixture of hydrofluoric and sulfuric acid (HF/H2SO4) was employed to theoretically investigate the reaction mechanism of the fluorine-based chemical method, since HF molecules are main reaction forms in the reaction. The results showed that the HF/ore ratio played a dominant role in the acid treatment, especially in the generation of fluorides. The added H2SO4 slightly accelerated the dissolution and affected the coordination equilibrium between Al3+ and F−. The dissolution conditions were also optimized that 98% of Li and 90% of Rb and Cs were efficiently converted into lixivium as sulfates using an ore/HF/H2SO4 ratio of 1:2:3.5 (g/mL/mL) at 85 °C for 3 h. Lepidolite was selectively dissolved over quartz, resulting in the relatively selective leaching of Li over Si and leaving amorphous SiO rich layers and K2SiF6 in the residue, which will be beneficial for the downstream processes of purification and separation. This investigation leads to advances in the understanding of the dissolution behavior with this fluorine-based chemical method and reflects the application potential of introducing fluorine to utilize lepidolite.Graphic abstractScheme of lepidolite dissolved in HF/H2SO4; M stands for metal elements such as K, Rb and Cs; [AlFn]3-n: coordination between Al3+ and F-, n: 1, 2, 3...6.Unlabelled Image
  • A novel method for preparing an As(V) solution for scorodite synthesis
           from an arsenic sulphide residue in a Pb refinery
    • Abstract: Publication date: Available online 13 November 2018Source: HydrometallurgyAuthor(s): Xu Ma, Mario A. Gomez, Zidan Yuan, Guoqing Zhang, Shaofeng Wang, Shifeng Li, Shuhua Yao, Xin Wang, Yongfeng Jia A novel method has been proposed to prepare an arsenate (As(V))-containing solution for scorodite formation using an arsenic (As) sulphide residue obtained from a Pb refinery. Preparation of the As(V) solution from the As sulphide residue included As oxidation leaching by alternating addition of a highly concentrated sodium hydroxide (c-NaOH 600 g/L) solution and hydrogen peroxide (H2O2) at 70 °C. This method gave an As leaching efficiency of up to 99% (total % recovery of As up to 90%), while at the same time, other metals could be recovered effectively (e.g., 95% Pb, 97% Cd, 90% Zn, and 96% Cu). Further oxidation and removal of the remaining arsenite (As(III)) in the leached filtrate by H2O2 indicated that the oxidation efficiency of oxidizing As(III) to As(V) was up to 99%. The As(V) solution produced by this process was suitable for As(V) fixation as scorodite. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the starting materials and output solids. The results showed that the major As phase in the As-containing compound of the initial As sulphide residue was As sulphide. Highly pure elemental sulphur (total % recovery of S up to 30%) was generated during the S(-II) elimination process, and the scorodite from the As(V) fixation process was highly crystalline. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray absorption near edge structure spectroscopy (XANES) were employed to characterize the intermediate filtrate of the process. The results showed that the intermediate filtrate was a multiphase mixture containing As(III), arsenate, sulphate, thio-arsenate, thio-sulphate and polysulphides (Sn2−). The produced scorodite showed good As stability in the TCLP and at pH 3 (0.47 mg/L), pH 5 (0.26 mg/L), and pH 7 (3.41 mg/L) in a 10-day short-term stability test.
  • Co+composite+anode+during+Zinc+electrowinning&rft.title=Hydrometallurgy&rft.issn=0304-386X&">Electrochemical performance of PbCo composite anode during Zinc
    • Abstract: Publication date: Available online 1 November 2018Source: HydrometallurgyAuthor(s): Maryam Karbasi, Eskandar Keshavarz Alamdarib, Elaheh Amirkhani Dehkordia In this study, the electrochemical and anodic behaviors of CoPb anodes in electrowinning process were investigated. Accumulative roll bonding (ARB) method was applied to fabricate CoPb composites. The electrochemical properties of the produced anodes were investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry technique (CV), electrowinning tests, and scanning electron microscopy (SEM). The results indicated that ARB-process is an appropriate method to developed CoPb anodes. The produced anodes containing 0.5% of Cobalt particles as a second phase after 10 cycles of ARB process which is named Pb-0.5%Co-10pass samples showed 83.37% increase in current density compared to pure lead anode. The results of electrowinning tests revealed that Pb-0.5%Co-10pass samples had the best anodic performance with a significant lower corrosion rate, product and electrolyte contamination, slime formation, energy consumption and a higher Zn deposit as a product and energy conservation.
  • Kinetic study of copper leaching from chalcopyrite concentrate in alkaline
           glycine solution
    • Abstract: Publication date: Available online 29 October 2018Source: HydrometallurgyAuthor(s): Doyun Shin, Junmo Ahn, Jaeheon Lee Recently, glycine, one of the simplest amino acids, has been emerging as an efficient and environmental-friendly lixiviant for copper leaching. In the present study, an alkaline glycine–peroxide lixiviant system was used to leach copper from chalcopyrite concentrate by a suite of kinetic studies under different conditions. The particle size of the concentrate was P80 40 μm. Glycine concentration was varied from 0.5 to 3.0 M (glycine to copper molar ratio of 1.1 to 6.6:1) and the pH was maintained at 11 during the experiment. The copper extraction within 96 h was observed from 13 to 14% with glycine concentrations from 0.5 to 2 M, while the copper extraction decreased at 3 M of glycine. By reconstituting the glycine concentration during the leach test and adding hydrogen peroxide periodically, the copper extraction with 1 M glycine at 96 h increased from 14 to 21%, respectively. By changing the glycine and hydrogen peroxide solution every 24 h, 42% of copper extraction was achieved within 168 h. With increasing temperature, copper extraction decreased, while iron dissolution increased. Copper sulfide and copper sulfate precipitates were found in the leaching liquor at 22 °C test. Poorly crystalline copper-iron sulfate phase was observed in the leaching liquor at 35 and 45 °C. This precipitation is believed to be one of the factors to decrease the copper recovery from chalcopyrite.
  • The adsorption of gold(I) on minerals and activated carbon (preg-robbing)
           in non-ammoniacal thiosulfate solutions - effect of calcium thiosulfate,
           silver(I), copper(I) and polythionate ions
    • Abstract: Publication date: Available online 24 October 2018Source: HydrometallurgyAuthor(s): O. Sitando, G. Senanayake, X. Dai, P. Breuer The ability of some typical gangue minerals and activated carbon to adsorb gold(I) (preg-robbing) in non-ammoniacal thiosulfate solutions was examined at different calcium thiosulfate concentrations. In the absence of calcium thiosulfate, sulfide minerals such as pyrite and chalcopyrite, and carbon were highly preg-robbing with 100% gold being adsorbed within half an hour. The oxide minerals examined including kaolinite, goethite and hematite were significantly less preg-robbing under the same conditions. The presence of free thiosulfate can significantly reduce or eliminate the preg-robbing of gold on mineral surfaces. With an initial thiosulfate concentration of 0.1 M, gold adsorption by oxide minerals was completely eliminated, while that of sulfide minerals and carbon was insignificant at 0.2 M free thiosulfate.Copper(I) was found to enhance the preg-robbing of gold by oxide minerals but to reduce the preg-robbing of gold by sulfide minerals and by carbon. Similar effect of silver(I) was observed except for chalcopyrite. Trithionate, a by-product of thiosulfate degradation, has no significant effect on the preg-robbing of gold(I). Tetrathionate, another by-product of thiosulfate degradation, significantly increases the preg-robbing of gold(I) onto pyrite. Activated carbon enhances the degradation of tetrathionate to trithionate and thiosulfate, the latter helps stabilise the gold(I) in solution.
  • Dissolution of calcium, phosphate, fluoride and rare earth elements (REEs)
           from a disc of natural fluorapatite mineral (FAP) in perchloric,
           hydrochloric, nitric, sulphuric and phosphoric acid solutions: A kinetic
           model and comparative batch leaching of major and minor elements from FAP
           and RE-FAP concentrate
    • Abstract: Publication date: Available online 6 September 2018Source: HydrometallurgyAuthor(s): A.M.T.S. Bandara, G. Senanayake Some rare earth phosphate minerals are associated with fluorapatite (FAP) in phosphate ores which make them a potential source of rare earth elements (REEs), to satisfy the increasing demand of REEs, especially for green energy technology and new energy materials. Previous studies have shown that the leachability of different elements which may be categorised as REEs and non-REEs in different acid solutions with the possibility of selective leaching of non-REEs by phosphoric acid to produce a REE rich leach residue which can be processed separately. This study investigates the dissolution of calcium, phosphate, fluoride and REEs from a rotating disc of a natural FAP mineral sample in perchloric, hydrochloric, nitric, sulphuric and phosphoric acid solutions under various leach conditions including different acid concentrations and temperatures and compares the results with batch leaching of natural FAP mineral and RE-FAP concentrate particles.The dissolution rate of REEs, which occur as minor elements in FAP mineral disc, are lower than that of the major elements: Ca, P and F. Higher dissolution rate of calcium from FAP disc in solutions of HCl, HNO3 and H2SO4 compared to HClO4 at high acid concentrations are due to the influence of Cl−, NO3− and SO42− ions, caused by association with Ca2+ ions in disc leaching, but precipitation of CaSO4 retard particle leaching in H2SO4. Despite the lower leaching rates of REEs due to low abundance of REEs on FAP mineral disc surface, the rates in 0.5 mol L−1 acid solutions follow the order H2SO4, HNO3 > HCl > HClO4 > H3PO4 indicating the beneficial effect of ion-association of the type RE(III)-sulfate/nitrate compared to RE(III)-phosphate precipitation. The higher leaching efficiencies of REEs in H3PO4 during first 10 min also decreases with prolonged leaching due to RE(III)-phosphate precipitation. The leaching efficiencies of Ca, Sr, Fe, Al and Mg are in the range 50–100% in 3.25 mol L−1 HCl, HNO3, HClO4 and H3PO4, compared to REEs, Th and U which vary in the range 20–80%, depending upon the formation of complex species or precipitation. A comparison between elemental composition of natural FAP mineral and a RE-FAP concentrate and their similarities in leaching behaviour in different acids is also presented highlighting the exceptional behaviour of phosphoric acid to selectively leach majority of non-REEs leaving REEs and silica in the leach residue.The surface reaction kinetic models and mechanisms are used to show that the dissolution reaction of calcium is mainly controlled by a chemical phenomenon in strong acids and phosphoric acid at the temperature range 25–50 °C. The experimental reaction orders with respect to H+ concentration in HCl, HNO3, HClO4, H2SO4 and H3PO4 in the range 0.46–0.93 for the dissolution reaction of calcium and/or phosphate are explained on the basis of stoichiometric dissolution and the influence of ion-association of anions with H+ and Ca2+.
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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Fax: +00 44 (0)131 4513327
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