Subjects -> METALLURGY (Total: 59 journals)
Showing 1 - 10 of 10 Journals sorted alphabetically
Acta Metallurgica Slovaca     Open Access   (Followers: 2)
Advanced Device Materials     Open Access   (Followers: 6)
American Journal of Fluid Dynamics     Open Access   (Followers: 44)
Archives of Metallurgy and Materials     Open Access   (Followers: 9)
Asian Journal of Materials Science     Open Access   (Followers: 4)
Canadian Metallurgical Quarterly     Hybrid Journal   (Followers: 21)
Complex Metals     Open Access   (Followers: 2)
Energy Materials : Materials Science and Engineering for Energy Systems     Hybrid Journal   (Followers: 24)
Graphene and 2D Materials     Open Access   (Followers: 6)
Handbook of Ferromagnetic Materials     Full-text available via subscription   (Followers: 1)
Handbook of Magnetic Materials     Full-text available via subscription   (Followers: 2)
High Temperature Materials and Processes     Open Access   (Followers: 6)
Indian Journal of Engineering and Materials Sciences (IJEMS)     Open Access   (Followers: 11)
International Journal of Metallurgy and Alloys     Full-text available via subscription   (Followers: 2)
International Journal of Metals     Open Access   (Followers: 7)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 12)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
Ironmaking & Steelmaking     Hybrid Journal   (Followers: 5)
ISIJ International - Iron and Steel Institute of Japan     Full-text available via subscription   (Followers: 26)
Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Proceedings of Higher Schools. Powder Metallurgy аnd Functional Coatings)     Full-text available via subscription   (Followers: 2)
JOM Journal of the Minerals, Metals and Materials Society     Hybrid Journal   (Followers: 35)
Journal of Advanced Joining Processes     Open Access  
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of Cluster Science     Hybrid Journal  
Journal of Heavy Metal Toxicity and Diseases     Open Access  
Journal of Iron and Steel Research International     Hybrid Journal   (Followers: 11)
Journal of Materials & Metallurgical Engineering     Full-text available via subscription   (Followers: 2)
Journal of Materials Processing Technology     Hybrid Journal   (Followers: 21)
Journal of Metallurgical Engineering     Open Access   (Followers: 4)
Journal of Sustainable Metallurgy     Hybrid Journal   (Followers: 3)
Materials Science and Metallurgy Engineering     Open Access   (Followers: 7)
Metal Finishing     Full-text available via subscription   (Followers: 20)
Metallurgical and Materials Engineering     Open Access   (Followers: 7)
Metallurgical and Materials Transactions A     Hybrid Journal   (Followers: 42)
Metallurgical and Materials Transactions B     Hybrid Journal   (Followers: 32)
Metallurgical and Materials Transactions E     Full-text available via subscription   (Followers: 2)
Metallurgical Research & Technology     Full-text available via subscription  
Metallurgical Research and Technology     Full-text available via subscription   (Followers: 8)
Metallurgy and Foundry Engineering     Open Access   (Followers: 3)
Mining, Metallurgy & Exploration     Hybrid Journal  
Powder Diffraction     Full-text available via subscription   (Followers: 1)
Powder Metallurgy     Hybrid Journal   (Followers: 35)
Powder Metallurgy and Metal Ceramics     Hybrid Journal   (Followers: 7)
Powder Metallurgy Progress     Open Access   (Followers: 5)
Practical Metallography     Full-text available via subscription   (Followers: 6)
Rare Metals     Hybrid Journal   (Followers: 3)
Revista de Metalurgia     Open Access  
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Revista Remetallica     Open Access   (Followers: 1)
Russian Metallurgy (Metally)     Full-text available via subscription   (Followers: 4)
Science and Technology of Welding and Joining     Hybrid Journal   (Followers: 8)
Soldering & Surface Mount Technology     Hybrid Journal   (Followers: 2)
Steel Times lnternational     Partially Free   (Followers: 19)
Transactions of the IMF     Hybrid Journal   (Followers: 14)
Transactions of the Indian Institute of Metals     Hybrid Journal   (Followers: 5)
Tungsten     Hybrid Journal  
Universal Journal of Materials Science     Open Access   (Followers: 3)
Welding in the World     Hybrid Journal   (Followers: 8)
Welding International     Hybrid Journal   (Followers: 11)
Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки     Open Access  
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Journal of Central South University
Journal Prestige (SJR): 0.336
Citation Impact (citeScore): 1
Number of Followers: 1  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2095-2899 - ISSN (Online) 2227-5223
Published by Springer-Verlag Homepage  [2656 journals]
  • Soil formation in bauxite residue: The most promising way to large-scale
           and ecological disposal
    • PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-3999-5
  • Recovery of iron and rare earth elements from red mud through an acid
           leaching-stepwise extraction approach
    • Abstract: A feasible approach to selectively recover iron and rare earth elements (REEs) from red mud through acid leaching-coordination-solvent extraction was proposed. The leaching efficiencies of Fe, Al, Ti, Sc, La, Ce, Nd and Y can reach up to 95.9%, 82.1%, 68.3%, 93.3%, 82.3%, 96.9%, 98.3% and 95.6%, respectively, under the optimal condition in the leaching process. Aliquat 336 showed excellent extraction performance of iron in chloride-rich solution, and the maximum extraction efficiency can reach over 96% in one time extraction while the loss of other metals was less than 10%, under the condition of Aliquat 336 concentration (v/v) of 30%, aqueous-organic ratio of 1.0 and extraction time of 20 min. Furthermore, P204 can effectively extract the scandium while Al and most other REEs remain in the aqueous phase. This approach may provide a new insight for the recovery of valuable resources from red mud.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4018-6
  • Industrial wastes applications for alkalinity regulation in bauxite
           residue: A comprehensive review
    • Abstract: Bauxite residue is a highly alkaline material generated from the production of alumina in which bauxite is dissolved in caustic soda. Approximately 4.4 billion tons of bauxite residues are either stockpiled or landfilled, creating environmental risks either from the generation of dust or migration of filtrates. High alkalinity is the critical factor restricting complete utilization of bauxite residues, whilst the application of alkaline regulation agents is costly and difficult to apply widely. For now, current industrial wastes, such as waste acid, ammonia nitrogen wastewater, waste gypsum and biomass, have become major problems restricting the development of the social economy. Regulation of bauxite residues alkalinity by industrial waste was proposed to achieve ‘waste control by waste’ with good economic and ecological benefits. This review will focus on the origin and transformation of alkalinity in bauxite residues using typical industrial waste. It will propose key research directions with an emphasis on alkaline regulation by industrial waste, whilst also providing a scientific reference point for their potential use as amendments to enhance soil formation and establish vegetation on bauxite residue disposal areas (BRDAs) following large-scale disposal.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4000-3
  • Colonization of Penicillium oxalicum enhanced neutralization effects of
           microbial decomposition of organic matter in bauxite residue
    • Abstract: Bauxite residue is a highly alkaline waste product from refining bauxite ore. Bioremediation driven by microbial activities has been evidently effective in lowering the alkalinity of bauxite residues, which is critical to the initiation of pedogenesis under engineered conditions. The present study investigated the changes of alkalinity and aggregation of bauxite residue at different depth in response to the colonization of Penicillium oxalicum in columns. The results demonstrated that the inoculation of P. oxalicum decreased the residue’s pH to about 7 after 30 d only at the surface layer, which was exposed to aerobic conditions. The formation of aggregates was improved overall in the organic matter treated bauxite residue. However, the EC of bauxite residue increased with time under the incubation condition, probably due to accelerated hydrolysis of sodium-rich minerals. The inoculation of P. oxalicum had no effects on urease activity, but increased cellulose enzyme activity at surface layer only.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4005-y
  • Preliminary assessment of revegetation potential through ryegrass growing
           on bauxite residue
    • Abstract: Bauxite residue (BR), a by-product of the industrial production of alumina, has raised environmental concerns in the last decades, due to the presence of high amounts of alkali and various heavy metal ions. Limited studies on the application of abandoned BR with massive consumption have been reported. In this study, the possibility of the revegetation using ryegrass growing on BR was discussed mainly through the growth indications and transfer of heavy metal ions in BR and plants. In the pot trails, ryegrass was seeded on BR, de-alkali BR, with (DBRO) or without (DBR) organic fertilizer, respectively. The results indicated that the remediation of bauxite residue can be achieved through de-alkali with acid neutralization. Elemental analysis indicated that the elements, except for Fe, Mn and Pb, were stable in plant roots, and ryegrass could hardly absorb Cd. But, some heavy metals such as Cu enriched in plants, which should be noted in revegetation on bauxite residue.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4012-z
  • Intensifying gibbsite precipitation from sodium aluminate solution by
           adding a mixed seed
    • Abstract: Gibbsite precipitation from sodium aluminate solution was intensified by adding mixed industrial and self-prepared active seeds, and its mechanism was researched preliminarily. The interfacial properties of seed/aluminate solution were determined for separate industrial and active seed. Contact angles of seed/aluminate solution and the specific surface area of seeds were respectively measured by sessile drop and BET method, and the morphology and particle size of precipitates were recorded by SEM and laser diffraction. The results show that, compared with the industrial seed, the active seed has a better wettability, lower interfacial tension, and larger specific surface area, being conducive to enhancing gibbsite precipitation from sodium aluminate solution. SEM analysis of the precipitates indicates that the embedment and accumulation/agglomeration of extremely fine particles on the surface of coarse industrial seed can effectively control the content of fine particles in the precipitation product. With extra 3.1–4.6 g/L active seed, the gibbsite precipitation ratio was increased by 3.23%–3.92%. Moreover, the mass percentage of particles <45 μm in precipitation product has even a slight decrease compared with that for the traditional precipitation product or of the industrial seed itself. The result presented is favorable to developing an intensified gibbsite precipitation process for commercial alumina manufacture.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4003-0
  • Physical, chemical, and surface charge properties of bauxite residue
           derived from a combined process
    • Abstract: A detailed understanding of the composition, buffering capacity, surface charge property, and metals leaching behavior of bauxite residue is the key to improved management, both in reducing the environmental impact and using the material as an industrial by-product for other applications. In this study, physical, chemical, and surface charge properties of bauxite residue derived from a combined process were investigated. Results indicated that the main alkaline solids in bauxite residue were katoite, sodalite, and calcite. These minerals also lead to a higher acid neutralizing capacity of bauxite residue. Acid neutralizing capacity (ANC) to pH 7.0 of this residue is about 0.9 mol H+/kg solid. Meanwhile, the Fe-, Al-, and Si-containing minerals in bauxite residue resulted in an active surface; The isoelectric point (IEP) and point of zero charge (PZC) were 7.88 and 7.65, respectively. This also leads to a fact that most of the metals in bauxite residue were adsorbed by these surface charged solids, which makes the metals not readily move under natural or even moderately acidic conditions. The leaching behavior of metals as a function of pH indicated that the metals in bauxite residue present low release concentrations (pH > 3).
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4009-7
  • Alkalinity stabilization behavior of bauxite residue: Ca-driving
           regulation characteristics of gypsum
    • Abstract: Alkaline anions, include CO32–, HCO3–, Al(OH)4–, OH–, continuously released from bauxite residue (BR), will cause a potential disastrous impact on surrounding environment. The composition variation of alkaline anions, alkaline phase transformation pathway, and micro-morphological transition characteristics during the gypsum addition were investigated in an attempt to understand alkalinity stabilization behavior. Results demonstrated that alkaline anions stabilization degree in leachates can reach approximately 96.29%, whilst pH and alkalinity were reduced from 10.47 to 8.15, 47.39 mmol/L to 2 mmol/L, respectively. During the alkalinity stabilization, chemical regulation behavior plays significant role in driving the co-precipitation reaction among the critical alkaline anions (CO32–, HCO3–, Al(OH)4–, OH–), with calcium carbonate (CaCO3)) being the most prevalent among the transformed alkaline phases. In addition, XRD and SEM-EDX analyses of the solid phase revealed that physical immobilization behavior would also influence the stability of soluble alkali and chemical bonded alkali due to released Ca2+ from gypsum which aggregated the clay particles and stabilized them into coarse particles with a blocky structure. These findings will be beneficial for effectively regulating strong alkalinity of BR.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4010-1
  • Treatment of bauxite residue dust pollution by improving structural
           stability via application of synthetic and natural polymers
    • Abstract: The residue drying area (RDA) is the major source of fugitive red sand (RS) dust emissions in the bauxite mining industry and causes serious environmental and safety detriments. Polymer stabilizer (PS) is one of the promising non-traditional stabilizers to mitigate such issues. This research investigated the unconfined compressive strength (UCS) of RS using synthetic polymer stabilizer (SPS) and natural polymer stabilizer (NPS), and to determine the optimum application concentration and mixing ratio of the PAM and Guar gum mixture. Results illustrated that PAM apparently outperform Guar gum in stabilizing sand particles. The mixture of PAM and Guar gum is more effective than individual use. The optimum polymer concentration and the mixing ratio are 0.94 wt.% and 0.6 (PAM: total (PAM + Guar gum)), respectively. A rigorous regression model was developed to predict the UCS value based on application concentration and mixing ratio for the purpose of cost and time efficiency.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4016-8
  • Removal of SO 2 from flue gas using Bayer red mud: Influence factors and
    • Abstract: The absorbent composing of Bayer red mud and water was prepared and applied to removing SO2 from flue gas. Effects of the ratio of liquid to solid (L/S), the absorption temperature, the inlet SO2 concentration, the O2 concentration, SO42- and other different components of Bayer red mud on desulfurization were conducted. The mechanism of flue gas desulfurization was also established. The results indicated that L/S was the prominent factor, followed by the inlet SO2 concentration and the temperature was the least among them. The optimum condition was as follows: L/S, the temperature and the SO2 concentration were 20:1, 25 °C and 1000 mg/m3, respectively, under the gas flow of 1.5 L/min. The desulfurization efficiency was not significantly influenced when O2 concentration was above 7%. The accumulation of SO42- inhibited the desulfurization efficiency. The alkali absorption and metal ions liquid catalytic oxidation were involved in the process, which accounted for 98.61%.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4019-5
  • Natural ripening with subsequent additions of gypsum and organic matter is
           key to successful bauxite residue revegetation
    • Abstract: The processes involved in the major steps of successful revegetation of bauxite residues are examined. The first phase is the natural physical, chemical and microbial ripening of the profile. This involves allowing the profile to drain, dry, shrink and crack to depth, leaching of soluble salts, alkalinity and Na down out of the surface layers, acidification by direct carbonation and natural seeding of tolerant vegetation with an accumulation of organic matter near the surface and an attendant development of an active microbial community. Following ripening, the surface layer can be tilled and gypsum and organic matter (e.g. manures, composts, biosolids) incorporated. These amendments result in a further decrease in pH, increase in Ca and other exchangeable cations, increased leaching of Na (with a reduction in exchangeable Na and ESP), improved physical properties, particularly aggregation, and a large increase in microbial activity. Other important considerations include the choice of suitable plant species tolerant to salinity/sodicity and local environmental conditions and the addition of balanced fertilizer applications.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4001-2
  • Rehabilitation of bauxite residue to support soil development and
           grassland establishment
    • Abstract: Rehabilitation (amendment and vegetation establishment) on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development. However, such approaches are inhibited by high pH, high exchangeable sodium (ESP) and poor nutrient status. Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth. Application of organics (e.g. compost) can address nutrient deficiencies but supplemental fertilizer additions may be required. A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates. Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue. Follow up monitoring over five years assessed elemental content in grassland and species dynamics. With co-application of the amendments several grassland species can grow on the residue. Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced. Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling. High pH, sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue. Following restoration several plant species can grow on amended residue.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4007-9
  • Isolation of an acid producing Bacillus sp . EEEL02: Potential for bauxite
           residue neutralization
    • Abstract: Bauxite residue deposit area (BRDA) is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity. Microbially-driven neutralization of bauxite residue, based on the microbial acid producing metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes. The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions. Several alkaliphilic acid producing bacteria were isolated in this study. One strain was selected for its superior growth pattern and acid metabolism (termed EEEL02). Based on the phylogenetic analysis, this strain was identified as Bacillus thuringiensis. The optimized fermentation conditions were as follows: pH 10; NaCl concentration 5%; temperature 25 °C; EEEL02 preferred glucose and peptone as carbon and nitrogen sources, respectively. Based on optimal fermentation conditions, EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test. Acetic acid, propionic acid and CO2 (g) were the major acid metabolites of fermentation, suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism. This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4006-x
  • Dynamic change and diagnosis of physical, chemical and biological
           properties in bauxite residue disposal areas
    • Abstract: Vegetation encroachment occurred in bauxite residue disposal area (BRDA) following natural weathering processes, whilst the typical indicators of soil formation are still uncertain. Residue samples were collected from the BRDA in Central China, and related physical, chemical and biological indicators of bauxite residue with different storage years were determined. The indicators of soil formation in bauxite residue were selected using principal component analysis, factor analysis, and comprehensive evaluation to establish soil quality diagnostic index model on disposal areas. Following natural weathering processes, the texture of bauxite residue changed from silty loam to sandy loam. The pH and EC decreased, whilst porosity, nutrient element content and microbial biomass increased. The identified minimum data set (MDS) included available phosphorus (AP), moisture content (MC), C/N, sand content, total nitrogen (TN), microbial biomass carbon (MBC), and pH. The soil quality index of bauxite residue increased, and the relative soil quality index decreased from 1.89 to 0.15, which indicated that natural weathering had a significant effect on improveing the quality of bauxite residue and forming a new soil-like matrix. The diagnostic model of bauxite residue was established to provide data support for the regeneration on disposal area.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4013-y
  • Bibliometric analysis of research on soil arsenic during 2005–2016
    • Abstract: Bibliometrics is an important branch in the field of information science, and it is widely used in many disciplines in modern research. A current active research subject can be analyzed and summarized from many aspects, such as the core institutions, core authors, highly cited papers, and keywords by using bibliometrics. This paper describes a bibliometric analysis regarding soil arsenic content by using the database from Web of Science to compare relevant research from work done domestically and abroad from 2005 to 2016. The results show that the relevant publications in China and overseas both dramatically increased from 2009, which indicates that research activity is expanding. The USA produced 27.3% of all relevant articles followed by China with 26.9% and India with 9.5%. Key issues mainly focused on agriculture and environmental science. Major journals studied include the following: Science of the Total Environment, Environmental and Experimental Botany, Environmental Pollution, Chemosphere, Journal of Hazardous Materials, Journal of Environmental Chemical Engineering, Journal of Geochemical Exploration, Ecotoxicology and Environmental Safety, Environmental Research, Talanta, and Applied Geochemistry. These are the most important journals in this field. In light of cooperation between countries, it is clear that China and the United States occupy the leading position.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4020-z
  • Effect of substrate amendment on alkaline minerals and aggregate stability
           in bauxite residue
    • Abstract: Bauxite residue is an alkaline waste material in the process of alumina production due to its characteristics of higher salinity and alkalinity, which results in environmental issues and extremely restricts the sustainable development of alumina industries. In this work, we conduct a column experiment to study the effects of two amendments on aggregate stability and variations in alkaline minerals of bauxite residue. The two amendments are phosphogypsum (PG) and phosphogypsum and vermicompost (PVC). The dominant fraction in aggregate is 1–0.25 mm in diameter on the surface, which takes up 39.34%, 39.38%, and 44.51 % for CK, PG, and PVC, respectively. Additions of PG and PVC decreased pH, EC, ESP, exchangeable Na+ concentration and the percentage of alkaline minerals, and then increased exchangeable Ca2+ concentration in bauxite residue. There was significant positive correlation between pH and exchangeable Na+ concentration, the percentage of cancrinite, tricalcium aluminate and calcite; while negative correlation was found in pH value versus exchangeable Ca2+ concentration. Theses findings confirmed that additions of phosphogypsum and vermicompost have a stimulative effect on aggregate stability in bauxite residue. In particular, amendment neutralization (phosphogypsum + vermicompost) in column represents an advantage for large-scale simulation of vegetation rehabilitate in bauxite residue disposal areas.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4011-0
  • Synergistic coagulation of bauxite residue-based polyaluminum ferric
           chloride for dyeing wastewater treatment
    • Abstract: Considering that Fe, Al elements in bauxite residue are active components for water purification, an effective polyaluminum ferric chloride (PAFC) coagulant derived from bauxite residue, with Fe2O3 content > 5.1%, Al2O3 % > 6.5%, basicity > 65%, was successfully prepared. The effect of as-prepared PAFC on the zeta potential for printing and dyeing wastewater was investigated. Comparing with polyferric chloride (PFC) and polyferric sulfate (PFS) for printing and dyeing wastewater treatment, prepared bauxite residue-based PAFC exhibited the optimal performance in the aspects of chromaticity and chemical oxygen demand (COD) removal rate. Furthermore, the combination of bauxite residue-based PAFC and PFS for synergy coagulation of such wastewater demonstrated an obvious positive effect. With the proportion between as-prepared PAFC and PFS to be 2.5:1, the COD of treated wastewater could be further reduced to meet the national level A standard of China, providing a promising route to solve the problem of substandard printing and dyeing sewage outfall by a simple coagulation strategy.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4017-7
  • Salt ions accumulation and distribution characteristics of pioneer plant
           species at a bauxite residue disposal area, China
    • Abstract: Bauxite residue disposal areas (BRDAs) are physically degraded and hostile to plant growth. Nevertheless, natural plant colonization was observed in an abandoned BRDA in Central China. The pioneer plant species at the disposal area were identified, whilst distribution characteristics of salt ions such as Na+, K+, and Ca2+ in plant tissues and rhizosphere residues were investigated. The mean concentration of exchangeable Na+ in the rhizosphere soils was 19.5 cmol/kg, which suggested that these pioneer plants had relatively high salinity resistance. Sodium content varied from 0.84 cmol/kg (Digitaria sanguinalis) to 39.7 cmol/kg (Kochia scoparia), whilst K to Na ratio varied from 0.71 (Myricaria bracteata) to 32.39 (Digitaria sanguinalis) in the shoots, which demonstrated that the salinity tolerance mechanisms of these pioneer species differed significantly. Accumulation factors of Na+ in local plant species ranged from 0.04 (D. sanguinalis) to 3.29 (M. bracteata), whilst the translocation factor varied from 0.13 (D. sanguinalis) to 2.92 (M. bracteata). The results suggested that four pioneer plant species including K. scoparia, M. bracteate, Cynodon dactylon and D. sanguinalis could be suitable for revegetation at other disposal areas.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4004-z
  • Equilibrium concentration of lithium ion in sodium aluminate solution
    • Abstract: Excess lithium in alumina is significantly bad for aluminum reduction. In this study, the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated. Elevating temperature, increasing caustic soda concentration, reducing alumina concentration or raising molar ratio α k improved equilibrium concentration of lithium ion in sodium aluminate solution. Agitation speed had a minimal effect on lithium ion concentration. Over 0.65 g/L lithium ion equilibrium concentration was observed in digestion process, whereas 35 mg/L lithium ion concentration remained in solution after precipitation time of 9 h. Moreover, equilibrium concentration decreased sharply from digestion of boehmite or diaspore to seed precipitation, about 95% lithium was precipitated into red mud (bauxite residue) and aluminum hydroxide. This study provides a valuable perspective in removal or extraction of lithium from sodium aluminate solution in alumina refineries.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4002-1
  • Variation of alkaline characteristics in bauxite residue under
           phosphogypsum amendment
    • Abstract: Aiming at alkaline problem of bauxite residue, this work focused variation of alkaline characteristics in bauxite residue through phosphogypsum treatment. The results demonstrated that the pH of bauxite residue reduced from initial 10.83 to 8.70 when 1.50 wt% phosphogypsum was added for 91 d. The removal rates of free alkali and exchangeable sodium were 97.94% and 75.87%, respectively. Meanwhile, significant positive correlations (P<0.05) existed between pH and free alkali, exchangeable sodium. The effect of free alkali composition was CO32–>OH–> AlO2–>HCO3–. In addition, alkaline phase decreased from 52.81% to 48.58% and gypsum stably presented in bauxite residue which continuously provided Ca2+ to inhibit dissolution of combined alkali. Furthermore, phosphogypsum promoted formation of macroaggregate structure, increased Ca2+, decreased Na+ and Al3+ on the surface of bauxite residue significantly, ultimately promoting soil formation in bauxite residue.
      PubDate: 2019-02-01
      DOI: 10.1007/s11771-019-4008-8
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