The Experts below are selected from a list of 1779 Experts worldwide ranked by ideXlab platform
A M Amer - One of the best experts on this subject based on the ideXlab platform.
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investigation of the direct Hydrometallurgical Processing of mechanically activated low grade wolframite concentrate
Hydrometallurgy, 2000Co-Authors: A M AmerAbstract:Experimental laboratory work on leaching of low-grade wolframite concentrate has shown that the dissolution of tungsten with a high extraction (90%) can only be reached after mechanical treatment of the studied wolframite concentrate, following oxidative leaching at 170°C in an autoclave in the presence of oxygen partial pressure of 10 bar. The effects of grinding time, temperature, sodium hydroxide concentration and oxygen partial pressure on the oxidation rate as well as the kinetics of the leaching process have been determined.
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a contribution to Hydrometallurgical Processing of low grade egyptian dolomite deposits
Hydrometallurgy, 1996Co-Authors: A M AmerAbstract:Abstract The applicability of carbon dioxide pressure leaching for the production of high purity magnesium oxide from low grade dolomite deposits from different localities in Egypt was investigated. More than 90% of magnesium can be extracted from dolomite ores (Khaboba and Giran El-Foul) under the following conditions: calcination temperature 750°C, leaching temperature 40°C, carbon dioxide pressure 600 kPa and leaching time 120 min. The kinetics of the carbonation process and physico-chemical characteristics of magnesium oxide product were also investigated.
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Leaching of a low grade Egyptian chromite ore
Hydrometallurgy, 1996Co-Authors: A M Amer, I. A. IbrahimAbstract:Abstract Hydrometallurgical Processing of low grade chromite (Barramiya, Egypt) is attained through leaching with sodium hydroxide of mechanically activated chromite ores under relatively high temperature (240‡C) in the presence of oxygen pressure (10 bar). The effects of temperature, grinding time, leaching time and oxygen partial pressure on chromium extraction were studied. The residual black sludge has a high iron content and nearly negligible chromium and sodium contents, which minimize disposal problems.
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investigation of the direct Hydrometallurgical Processing of mechanically activated complex sulphide ore akarem area egypt
Hydrometallurgy, 1995Co-Authors: A M AmerAbstract:Abstract Experimental laboratory work on leaching complex sulphide ore has shown that the dissolution of nickel, copper and cobalt with a high extraction rate can only be reached after mechanical treatment of the ores, following oxidative leaching at 110°C, in an autoclave with an oxygen partial pressure of 10 bar. The effects of grinding time, temperature, initial acid concentration and oxygen partial pressure on the oxidation process rate have been determined.
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Hydrometallurgical Processing of egyptian black shale of the quseir safaga region
Hydrometallurgy, 1994Co-Authors: A M AmerAbstract:Abstract Hydrometallurgical Processing of black shale (Quseir-Safaga region) is attained through leaching with sulphuric acid under oxygen pressure (atmospheric leaching leads to complete dissolution of both vanadium and iron). Separation of iron from vanadium is very difficult, due to the narrow pH precipitation range of the two metals (pH 2–3). Leaching under oxygen pressure leads to the oxidation of iron and its precipitation as basic iron sulphate, leaving vanadium in solution. The kinetics of the leaching processes were investigated and the optimum leaching conditions were determined.
Antony Van Der Ent - One of the best experts on this subject based on the ideXlab platform.
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characterisation and Hydrometallurgical Processing of nickel from tropical agromined bio ore
Hydrometallurgy, 2017Co-Authors: James Vaughan, Justin Riggio, Jeff Jiang Chen, Hong Peng, Hugh H Harris, Antony Van Der EntAbstract:Hyperaccumulator plants ("metal crops") can be used for selective extraction of Ni from low-grade resources, thereby producing a high-grade "bio-ore". This so-called agromining (or phytomining) technology involves farming select metal crops on ultramafic soils, mineral wastes, or overburden that are sub-economic Ni resources for conventional extractive technology. Key to profiting from agromining is the efficient recovery of Ni and by-products from the bio-ore, either directly from freshly harvested biomass or from the ash after incineration. Bio-ore of wild grown specimens of the Ni hyperaccumulator plants Rinorea bengalensis and Phyllanthus securinegoides were collected in Malaysia. After incineration, the ash composites contained 5.5.and 12.7 wt% Ni for Rinorea and Phyllanthus respectively, along with substantial amounts of Ca, K, C, Mg, P, Na, S and Cl. Other minor impurities included Si, Fe, Al, Mn and Zn. The solids were characterised in detail by SEM-EDS, XRD and XANES. The effect of solution chemistry on the leaching behaviour of the bio-ore (dried biomass and ash) was also assessed. A Hydrometallurgical process for recovering Ni from the bio-ore was then demonstrated. The processes involves the bio-ore (ash) being water-washed, yielding >90% recovery of K to solution. After water washing, >95% Ni recovery was achieved by H2SO4 leaching at 60 degrees C, although long residence times and high acid concentrations were required. Ni(OH)(2) was then precipitated from solution using the K2CO3 rich wash-water. The bio-ore generated precipitant was compared with NaOH and MgO used industrially. (C) 2017 Elsevier B.V. All rights reserved.
J. Capek - One of the best experts on this subject based on the ideXlab platform.
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Iron removal from zinc liquors originating from Hydrometallurgical Processing of spent Zn/MnO2 batteries
Hydrometallurgy, 2013Co-Authors: J. Formanek, J. Jandova, J. CapekAbstract:Abstract In this work, the removal of iron from leach liquors obtained after Processing of spent alkaline and zinc-carbon Zn/MnO2 batteries with initial iron ion concentration in the range of 270 to 580 mg/L has been studied. Solid Na2CO3, ZnO and fine ground waste electrode materials separated from processed Zn/MnO2 batteries were tested as precipitation agents. All used precipitation agents make it possible to remove more than 99% Fe, but electrode materials have been found to be more efficient precipitants at lower pH values. The different course of iron precipitation is probably caused by different solubility of iron compounds formed during the precipitation with various precipitation agents. Precipitates in which iron was present as FeO(OH) originated from Processing the leach liquors with Na2CO3 or ZnO Precipitates from Processing the leach liquors with electrode materials contained zinc-iron non-stoichiometric oxides, which was established as results of experiments performed with a synthetic solution containing 1.54 g/L Fe. The benefits of potential use of waste materials containing zinc oxide compounds in applications to remove iron from zinc sulphate liquors would include high efficiency, low cost and good filterability of the formed precipitates.
Manis Kumar Jha - One of the best experts on this subject based on the ideXlab platform.
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Hydrometallurgical Processing of waste multilayer ceramic capacitors mlccs to recover silver and palladium
Hydrometallurgy, 2020Co-Authors: Manis Kumar Jha, Rekha Panda, Om Shankar Dinkar, Devendra Deo PathakAbstract:Abstract Present paper reports an application oriented approach to recover precious metals such as silver (Ag) and palladium (Pd) from multilayer ceramic capacitors (MLCCs) of waste printed circuit boards (PCBs). These capacitors are being widely used in modern electronic gadgets to provide advance features as well as to enhance their performance. Due to the generation of large amount of e-waste as well as the loss of precious metals, a sincere R&D effort has been made to develop a process for the recovery of Ag and Pd from waste MLCCs. Initially, the MLCCs were depopulated from the PCBs by de-soldering using thermal treatment. Further, the depopulated material was pulverised to get homogeneous fine powder of MLCCs, which contained 0.14% Pd, 1.08% Ag, 1.76% Cu and 11.1% Ni. First of all Ni was removed/recovered selectively using two stages of leaching at optimized condition i.e. 2 M HCl, temperature 75 °C and pulp density 100 g/L. The obtained leached residue was washed, dried and further leached to get 99.99% Ag and Pd both in solution using 4 M HNO3, temperature 80 °C, pulp density 100 g/L and mixing time 1 h. From the obtained leach liquor, salt of Ag (purity 99.99%) was selectively recovered/precipitated using KCl. Further, Cu was extracted from the Ag depleted solution using LIX 84IC leaving Pd in the raffinate, which was evaporated to get pure Pd salt. The developed flow-sheet has potential to be commercialized after scale up trials.
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review of Hydrometallurgical recovery of zinc from industrial wastes
Resources Conservation and Recycling, 2001Co-Authors: Manis Kumar Jha, Vinay Kumar, R SinghAbstract:Zinc containing wastes/secondaries viz. zinc ash, dross, flue dusts, sludge, residue etc. are generated in various chemical and metallurgical industries. The materials contain different level of impurities depending on the source. The Hydrometallurgical Processing is effective and flexible for treating such materials as it can control the different level of impurities. Depending on the nature and composition of the secondaries, a suitable lixiviant could be selected to dissolve the desired metals leaving gangue in the residue. In the present paper, the Hydrometallurgical processes have been described for the recovery of zinc from the secondaries using sulphuric acid, hydrochloric acid, ammoniacal solution and sodium hydroxide etc. as lixiviants. The leach solution thus obtained has been purified with respect to dissolved impurities using precipitation, ion exchange or solvent extraction method. The metal or salt is produced from the purified solution by electrolysis or crystallization.
Fernanda Margarido - One of the best experts on this subject based on the ideXlab platform.
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recovery of lithium carbonate by acid digestion and Hydrometallurgical Processing from mechanically activated lepidolite
Hydrometallurgy, 2018Co-Authors: Nathália Vieceli, M F C Pereira, Carlos Guimarães, F. O. Durao, Carlos A. Nogueira, Fernanda MargaridoAbstract:Abstract Lithium extraction from hard-rock ores has regained importance due to the increased demand for this metal to supply the growing battery market. Therefore, several studies have been focused on the lithium extraction from ores, however, leaching and purification steps are sparsely studied. Thus, the objective of this study was to evaluate the main factors affecting the water leaching step and the subsequent purification operations for lithium recovery from a lepidolite concentrate, which was processed by mechanical activation and sulphuric acid digestion. In the leaching step, among the variables studied, only one, the leaching temperature, showed a significant effect on the lithium extraction, taking into account the range of values tested. Thus, the recommended operating value for the leaching time and the L/S ratio is the minimum, while for the leaching temperature is 50°C. After optimizing the leaching operation, the purification of the leachate, by neutralization, was thoroughly performed by efficient removal of impurities (Fe, Al, Mn and Ca), allowing to obtain lithium carbonate as final product, as well as other relevant by-products, such as rubidium and potassium alums.
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integration of physical operations in the Hydrometallurgical Processing of spent zn mno2 batteries
EBR’09 - Electronics & Battery Recycling ’09, 2009Co-Authors: Fatima Pedrosa, J P Feu, Marta Cabral, C A Nogueira, Fernanda MargaridoAbstract:The recycling of spent Zn-MnO2 batteries by hydrometallurgy involves the leaching of material previously treated by physical Processing to allow the liberation of electrode particles and the separation of unwanted scrap. The integration of these physical operations with leaching is therefore crucial for the optimization of the process, allowing achieving high recovery yields of zinc and manganese and minimizing reactants consumption and iron contamination. In this paper, several options involving physical Processing and leaching with sulphuric acid are presented and discussed. After batteries shredding and disaggregation, the separation of steel scrap was performed by sieving or magnetic separation, and the remaining solids were treated by leaching. These options were compared, in terms of metals recovery and contamination, with the alternative of direct leaching of all the shredded fractions without physical treatment. The separation of the steel scrap by sieving or magnetic separation allowed the removal from the circuit of 37 or 49% of iron, respectively, with losses of 15 or 6% of zinc and 2 or 4% of manganese. Therefore more than 50% of iron remained in the process, which was attributed to the presence of iron oxides formed by the corrosion of the battery cases. In the leaching operation, zinc dissolution was very effective (yields above 97%) while manganese is strongly depended from the process option, being its leaching proportional to the presence of scrap (yields of 80%, 56% and 43%, respectively in direct leaching, sieving / leaching and magnetic separation / leaching). These results showed that iron plays an important role in the reductive leaching of manganese species (III or IV), and so the presence of steel scrap in leaching, besides disadvantages concerning solutions contamination, contributes positively for the leaching efficiency.
