Papers by Keyword: Hydrometallurgy

Abstract: The cathode material of the lithium-ion battery in this study is LiNi_0.5Mn_0.3Co_0.2O₂ (NMC532) with a mole ratio of Ni, Mn, and Co respectively 5:3:2. The purpose of this research was aimed for direct using of MHP as the nickel source to NMC532 as cathode material can greatly reduce the overall production cost due to shorter supply chain of nickel which is beneficial for commercialization of cathode material. The Mix Hydroxide Precipitate (MHP) was leached by acetic acid to earn nickel acetate. Then, to make NMC532 by co-precipitation method, the nickel acetate was reacted with MnSO₄.H₂O, CoSO₄.7H₂O, and C₂H₂O₄.2H₂O. Based on the XRD and FTIR analysis, NMC532 exhibited a high crystalline layered structure with no observable impurity peaks even with the presence of impurities such as other metals or organic groups contained in MHP. SEM images showed homogenous particles with polycrystalline morphology. Charge-discharge analysis performed in cylindrical cell type 18650 showed promising results such as excellent cycle performances with specific charge capacity 179.14 mAh/g and specific discharge capacity 111.19 mAh/g. The rate ability could perform stable in every current density (0.1C, 1C, 4C, 8C, and 16C) and retested again in 0.1C with the initial capacity 90.89 mAh/g. The overall process can be considered as cheap and economically attractive to be adapted at industrial scale.

Abstract: Spent lithium-ion batteries (LIBs) have significantly increased due to the high consumption of LIBs for automobile applications; therefore, the recovery of valuable materials to use as the second resource can bring economic benefits and reduce an environmental impact. This study investigated the production of lithium phosphate (Li₃PO₄), which can be used as a starting material for the synthesis of LIBs, from spent LiNi_xMn_yCo_zO₂ (NMC) cathodes. The experimental procedure started with discharging, dismantling the battery, and removing the aluminum foil, followed by the leaching of cathode material before precipitating the lithium phosphate from the solution. In the leaching stage, the parameters to optimize the process were studied. The results showed that the lithium leaching efficiency could be achieved at 96.10% using 2 M H₂SO₄, 8 vol.% H₂O₂, 40 g/L pulp density, and 4 hrs at 70°C. The final precipitate product of 98.98% purity of Li₃PO₄ was recovered from the solution using Na₂HPO₄ under the experimental condition.

Abstract: The possibility of sorption extraction of nickel from leaching solutions of oxidized nickel ores of the Buruktal deposit is considered. Ionite Lewatit TP220 with bis-picolylamine functional groups is effective for nickel recovery against the background of high iron contents. Lewatit TP220 is mechanically strong enough for use in the resin-in-pulp process. Nickel sorption with satisfactory performance occurs both in the variant of sorption leaching and extraction from clarified solutions. At sorption from the pulp, the capacity for nickel was 5.44 mg/g, for iron, 25.17 mg/g. The use of 20% sulfuric acid provides quantitative nickel desorption. To obtain a higher quality nickel-containing product, it is recommended to additionally purify the resulting eluates from iron.

Abstract: The aim of this study was to develop a recycling process to recover silver metal from solar panel waste. Experimental procedure consisted of mechanical/physical separation, leaching of silver from silicon wafer and precipitation to retrieve silver chloride (AgCl) precipitate. The precipitated AgCl was reduced to silver precipitate form which was subsequently heated up to produce silver metal. The leaching process was first conducted by using 4 M of nitric acid for 24 hrs. The silver-containing leached solution would then be added by sodium chloride solution to precipitate AgCl. The precipitate was filtrated out from the solution and was rinsed with water ready for further step. The rinsed precipitate was dissolved in water, then sucrose and sodium hydroxide were added to achieve precipitated silver. Finally, the precipitated silver was burned with acetylene gas to finally obtain silver metal. Base on the experiment the purity of silver metal of 99.98% can be achieved and by considering recycling of solar panel of 1,000 kg the recycling product of pure silver of 0.23 kg could be acquired.

Abstract: Indonesia coal ash is predicted to reach 10.8 million tons in the year 2020 but its utilization is still limited. In the last decade, coal ash has become a promising REY source candidate. To determine the potency of REY in Indonesia coal ash, information about element concentration and mineralogy of the ash is essential. In this study, coal ash samples were taken from Paiton-2, Pacitan, Rembang, and Tanjung Jati coal-fired power plants. Element content and mineralogy were analyzed using Inductive Couple Plasma Mass Spectroscopy/Atomic Emission Spectroscopy (ICP-MS/AES), X-Ray Diffractometer (XRD) and petrographic. The results showed that coal fly ash and bottom ash contains critical REY in the range of 38% to 41% with C_outlook larger than one. XRD analysis showed that both fly ash and bottom ash have similar mineral phases with slightly different concentrations. The mineral phase is dominated by amorphous glass, quartz, Fe-bearing minerals, and unburned carbon. The amorphous glass phase in fly ash is in the range of 23 to 34% while in bottom ash between 14 and 34%. Unburned carbon content in fly ash and bottom ashes are 7-13% and 7-19%, respectively. Fe-bearing mineral content in fly ash is 15-20% and bottom ash is 13-20%. In addition, Indonesia coal ash has a higher Heavy-REY enrichment factor than Light-REY. The Enrichment Factor of HREY in fly ash is as much as 1.3 times (in average) of the bottom ash.

Abstract: The goal of the present work was to perform bioleaching of uranium from low grade ore from Vostok deposit (Republic of Kazakhstan), which was previously subjected to long-term acid leaching. The ore initially contained from 0.15 to 0.20% of uranium in the form of uraninite, but ore samples used in the study contained about 0.05% of uranium, as it was exhausted during acid leaching, and uranium was partially leached. Representative samples of ore were processed in 1 m columns, leach solutions containing 5, 10, 20 g/L of sulfuric acid and bacterial cells (about 10⁴) were percolated through the ore. Leaching was performed at ambient temperature for 70 days. In one of the percolators, the leaching was performed with leaching solution containing 10 g/L of H₂SO₄, cells of A. ferrooxidans, and 0.5 g/L of formaldehyde. Leaching with the solution containing 5, 10, and 20 g/L of sulfuric acid made it possible to extract 50, 53, and 58% of uranium. Addition of formaldehyde in leach solution led to the decrease in uranium extraction extent down to 37%. Thus, the results of the present work demonstrated that uranium ore exhausted during long-term acid leaching may be successfully subjected to bioleaching, that allows extracting residual quantities of uranium. Leaching rate of uranium from exhausted ore depended on both sulfuric acid concentration and microbial activity of bacteria isolated from acid mine drainage, formed on uranium deposit. In the same time, acid mine drainage may be used as a source of inoculate, to start bioleaching process.

Abstract: Modern methods of recycling spent automotive catalysts and their main disadvantages in industrial practice are considered. The electrochlorination method is proposed as the basis of the platinum-group metals extraction technology after electric arc melting of ceramic catalysts carrier material. The results of the experimental work on the extraction of platinum, palladium, rhodium are analyzed.

Abstract: Autoclave oxidative leaching is one of the most promising hydrometallurgical approaches for copper suplhide materials processing. In previous studies [2–4], the possibility of an efficient autoclave treatment of chalcopyrite concentrate was confirmed. The concentrate has the following chemical composition, %: 21.5 Cu, 0.1 Zn, 26.5 S, 24.5 Fe, 0.05 Pb, 0.04 Ni, 16.2 SiO₂ [1]. At high temperature conditions (190–200 °C; 4–6 bar) in sulfuric-acid media during 100–120 min about 98% Cu was extracted. A leaching residue after POX (POX-cake) contained the following compounds, %: 55 Fe₂O₃, 40 SiO₂, 4 MeS₂/MeS. Current paper presents the results on purification of POX-cakes from iron by autoclave treatment. Futher ways for by-products (SiO₂-cake and FeSO₄-solution) processing are sugested.

Abstract: Ural enrichment plants processing copper-porphyry deposits are produced chalcopyrite concentrates of the following chemical composition, %: 21.5 Cu, 0.1 Zn, 26.59 S, 24.52 Fe, 0.05 Pb, 0.04 Ni, 16.28 SiO₂ [1]. According to previous studies [2, 3, 21], such concentrates can be effectively treated using pressure oxidative leaching (POX). At temperature of 190–200 °C, partial oxygen pressure 4–6 bar and [H₂SO₄] = 15–30 g / L during 100-120 min about 98 % Cu was extracted. In this paper, an inluence of chalcopyrite concentrate preliminary grinding on efficiency of the POX stage was studied. It was found that even the finest grinding of the particle size class P₈₀ = 13 μm does not lead to significant intensification of process kinetics.

Abstract: Currently, in non–ferrous metallurgy, hydrometallurgical methods are practiced for metal recovering from copper ore in addition to pyrometallurgy, for example, SX–EW (solvent extraction–electrowinning). Although this technology gives the opportunity to get cathode copper from oxidized ores without thermal impact on the material, it has several disadvantages, one of which is the formation of interphase suspension or “crud” in the extraction process. The interphase suspension impedes and worsens extraction process performances and carries away the large number of valuable components, such as extractant, diluent and copper–containing solution. At present, this interphase suspension is not recycled, instead it is drained from the extractor and stored. Interphase suspension recycling is a highly relevant problem of hydrometallurgical production.