Separation and recovery of cesium sulfate from the leach solution obtained in the sulfuric acid baking process of lepidolite concentrate

The present paper is focused on the extraction of gold from high-grade e-waste, i.e., spent electronic connectors and plates, by leaching and electrowinning. These connectors are usually made up of an alloy covered by a layer of gold; sometimes, in some of them, a plastic part is also present. The applied leaching system consisted of an acid solution of diluted sulfuric acid (0.2 mol/L) with thiourea (20 g/L) as a reagent and ferric sulfate (21.8 g/L) as an oxidant. This system was applied on three different high-grade e-waste, namely: (1) Connectors with the partial gold-plated surface (Au concentration—1139 mg/kg); (2) different types of connectors with some of which with completely gold-plated surface (Au concentration—590 mg/kg); and (3) connectors and plates with the completely gold-plated surface (Au concentration—7900 mg/kg). Gold dissolution yields of 52, 94, and 49% were achieved from the first, second, and third samples, respectively. About 95% of Au recovery was achieved after 1.5 h of electrowinning at a current efficiency of only 4.06% and current consumption of 3.02 kWh/kg of Au from the leach solution of the third sample.

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Uranium Bioleaching from Low Grade Ore

Materials Science Forum ◽

10.4028/www.scientific.net/msf.989.559 ◽

2020 ◽

Vol 989 ◽

pp. 559-563

Author(s):

Ashimkhan T. Kanayev ◽

Khussain Valiyev ◽

Aleksandr Bulaev

Keyword(s):

Sulfuric Acid ◽

Acid Mine Drainage ◽

Mine Drainage ◽

Sulfuric Acid Concentration ◽

Acid Leaching ◽

Leach Solution ◽

Low Grade ◽

Bacterial Cells ◽

Acid Mine

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.

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Basic Sulfate Precipitation of Zirconium from Sulfuric Acid Leach Solution

Metals ◽

10.3390/met10081099 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1099 ◽

Cited By ~ 1

Author(s):

Yiqian Ma ◽

Srecko Stopic ◽

Xuewen Wang ◽

Kerstin Forsberg ◽

Bernd Friedrich

Keyword(s):

Sulfuric Acid ◽

Leach Solution ◽

Precipitation Method ◽

Zirconium Sulfate ◽

Acid Leach ◽

Low Concentrations ◽

Quality Product ◽

Reported Study ◽

Co Precipitation ◽

High Quality Product

H2SO4 was ensured to be the best candidate for Zr leaching from the eudialyte. The resulting sulfuric leach solution consisted of Zr(IV), Nb(V), Hf(IV), Al(III), and Fe(III). It was found that ordinary metal hydroxide precipitation was not feasible for obtaining a relatively pure product due to the co-precipitation of Al(III) and Fe(III). In this reported study, a basic zirconium sulfate precipitation method was investigated to recover Zr from a sulfuric acid leach solution of a eudialyte residue after rare earth elements extraction. Nb precipitated preferentially by adjusting the pH of the solution to around 1.0. After partial removal of SO42− by adding 120 g of CaCl2 per 1L solution, a basic zirconium sulfate precipitate was obtained by adjusting the pH to ~1.6 and maintaining the solution at 75 °C for 60 min. Under the optimum conditions, the loss of Zr during the SO42− removal step was only 0.11%, and the yield in the basic zirconium sulfate precipitation step was 96.18%. The precipitate contained 33.77% Zr and 0.59% Hf with low concentrations of Fe and Al. It was found that a high-quality product of ZrO2 could be obtained from the basic sulfate precipitate.

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Sustainable Hydrometallurgical Recovery of Valuable Elements from Spent Nickel–Metal Hydride HEV Batteries

Metals ◽

10.3390/met8121062 ◽

2018 ◽

Vol 8 (12) ◽

pp. 1062 ◽

Cited By ~ 9

Author(s):

Kivanc Korkmaz ◽

Mahmood Alemrajabi ◽

Åke Rasmuson ◽

Kerstin Forsberg

Keyword(s):

Sulfuric Acid ◽

Hydrochloric Acid ◽

Hybrid Electric Vehicle ◽

Active Material ◽

Sulfuric Acid Concentration ◽

Dissolution Kinetics ◽

Leach Solution ◽

Nickel Metal ◽

Acid Leach ◽

Kinetics Of

In the present study, the recovery of valuable metals from a Panasonic Prismatic Module 6.5 Ah NiMH 7.2 V plastic casing hybrid electric vehicle (HEV) battery has been investigated, processing the anode and cathode electrodes separately. The study focuses on the recovery of the most valuable compounds, i.e., nickel, cobalt and rare earth elements (REE). Most of the REE (La, Ce, Nd, Pr and Y) were found in the anode active material (33% by mass), whereas only a small amount of Y was found in the cathode material. The electrodes were leached in sulfuric acid and in hydrochloric acid, respectively, under different conditions. The results indicated that the dissolution kinetics of nickel could be slow as a result of slow dissolution kinetics of nickel oxide. At leaching in sulfuric acid, light rare earths were found to reprecipitate increasingly with increasing temperature and sulfuric acid concentration. Following the leaching, the separation of REE from the sulfuric acid leach liquor by precipitation as NaREE (SO4)2·H2O and from the hydrochloric acid leach solution as REE2(C2O4)3·xH2O were investigated. By adding sodium ions, the REE could be precipitated as NaREE (SO4)2·H2O with little loss of Co and Ni. By using a stoichiometric oxalic acid excess of 300%, the REE could be precipitated as oxalates while avoiding nickel and cobalt co-precipitation. By using nanofiltration it was possible to recover hydrochloric acid after leaching the anode material.

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Recovery of molybdenum and vanadium with high purity from sulfuric acid leach solution of spent hydrodesulfurization catalysts by ion exchange

Hydrometallurgy ◽

10.1016/j.hydromet.2014.05.010 ◽

2014 ◽

Vol 147-148 ◽

pp. 142-147 ◽

Cited By ~ 26

Author(s):

Thi Hong Nguyen ◽

Man Seung Lee

Keyword(s):

Sulfuric Acid ◽

Ion Exchange ◽

High Purity ◽

Leach Solution ◽

Hydrodesulfurization Catalysts ◽

Acid Leach

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Studies on zinc recovery from technogenic waste

E3S Web of Conferences ◽

10.1051/e3sconf/202129503008 ◽

2021 ◽

Vol 295 ◽

pp. 03008

Author(s):

Marinela Panayotova ◽

Vladko Panayotov

Keyword(s):

Hydrogen Peroxide ◽

Sulfuric Acid ◽

Laboratory Experiments ◽

Environmentally Friendly ◽

Leach Solution ◽

Secondary Source ◽

Atmospheric Conditions ◽

Zinc Recovery ◽

Technogenic Waste ◽

Lead Zinc

Results from laboratory experiments are presented on extraction of zinc available in waste from lead-zinc metallurgy, mixed with lead-zinc flotation tailings and some waste rock, by leaching it under atmospheric conditions with sulfuric acid (H2SO4) solutions (5 and 10 wt. %) and 30 % hydrogen peroxide in the temperature range of 25 - 80 °C, at leaching time 30 - 120 min. Material leaching with 10 % H2SO4 solution at 70 °C for one hour brings into pregnant leach solution (PLS) around 80 % of zinc available. Imposing an electrochemical impact during the leaching process increases the quantity of leached zinc by around 5 %. Direct electrowinning from the PLS obtains zinc metal of grade 75-76 %. The suggested treatment removes metals-pollutants from accumulated mixed technogenic waste therefore rendering it more environmentally friendly. Experiments showed that old mixed waste from mining, mineral processing and metallurgy activities merits further studies as secondary source of metals.

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Analyzing changes in a leach solution oxygenation in the process of uranium ore borehole mining

Mining of Mineral Deposits ◽

10.33271/mining15.03.039 ◽

2021 ◽

Vol 15 (3) ◽

pp. 39-44

Author(s):

Erbolat Aben ◽

Bakytzhan Toktaruly ◽

Nursultan Khairullayev ◽

Mukhtar Yeluzakh

Keyword(s):

Sulfuric Acid ◽

Flow Velocity ◽

Oxygen Concentration ◽

Acid Concentration ◽

Reduction Potential ◽

Sulfuric Acid Concentration ◽

Leach Solution ◽

Oxidation Reduction ◽

Oxidation Reduction Potential ◽

Solution Volume

Purpose is to increase uranium content in a PR solution while developing a technique varying oxidation-reduction potential of a leach solution with its oxygenation and identify changes in the oxygenation depending upon sulfuric acid concentration as well as transportation distance of the solution. Methods. A laboratory facility, involving solution tank, pump, Venturi tube, tank to install oxygen analyzer, and a dump tank, has been manufactured under the lab conditions to determine a leach solution oxygenation taking into consideration its delivery rate, sulfuric acid concentration, and temporal preservation of the concentration. Solution flow velocity; the deli-vered solution volume; sulfuric acid concentration; and distance from oxygenation point to a seam changed and varied during the study. Oxygenation was measured with the help of AZ 8403 oximeter; IT-1101 device was used to measure pH value as well as oxidation-reduction potential (ORP). Findings. A technique for a leach solution oxygenation and results of laboratory tests to identify influence of a sulfuric acid as well as transportation distance of a solution on oxygen concentration in the solution have been represented. It has been determined that Venturi tube helps oxygenize a leach solution; in this context, maximum oxygen concentration is achieved if a flow velocity is optimum one. It has been specified that a solution oxygenating depends upon a sulfuric acid concentration decreasing moderately with the increasing distance of the solution transportation. Originality.Following new dependencies have been determined: oxygen concentration in a solution upon a flow velocity and solution volume; and oxygen concentration in a solution upon distance from concentration place and sulfuric acid concentration. Practical implications.A leach solution oxygenation results in the increased oxidation-reduction potential and in the increased content of a useful component in the pregnant solution respectively. The proposed technique is notable for its low capital spending. Moreover, it is integrated easily into the available system being absolutely environmentally friendly.

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Recovery of water and acid from leach solutions using direct contact membrane distillation

Water Science & Technology ◽

10.2166/wst.2013.788 ◽

2013 ◽

Vol 69 (4) ◽

pp. 868-875 ◽

Cited By ~ 17

Author(s):

Uchenna K. Kesieme ◽

Nicholas Milne ◽

Chu Yong Cheng ◽

Hal Aral ◽

Mikel Duke

Keyword(s):

Sulfuric Acid ◽

Direct Contact ◽

Separation Efficiency ◽

Free Acid ◽

Feed Solution ◽

Membrane Distillation ◽

Leach Solution ◽

Water Recovery ◽

Direct Contact Membrane Distillation ◽

Quality Water

This paper describes for the first time the use of direct contact membrane distillation (DCMD) for acid and water recovery from a real leach solution generated by a hydrometallurgical plant. The leach solutions considered contained H2SO4 or HCl. In all tests the temperature of the feed solution was kept at 60 °C. The test work showed that fluxes were within the range of 18–33 kg/m2/h and 15–35 kg/m2/h for the H2SO4 and HCl systems, respectively. In the H2SO4 leach system, the final concentration of free acid in the sample solution increased on the concentrate side of the DCMD system from 1.04 M up to 4.60 M. The sulfate separation efficiency was over 99.9% and overall water recovery exceeded 80%. In the HCl leach system, HCl vapour passed through the membrane from the feed side to the permeate. The concentration of HCl captured in the permeate was about 1.10 M leaving behind only 0.41 M in the feed from the initial concentration of 2.13 M. In all the experiments, salt rejection was >99.9%. DCMD is clearly viable for high recovery of high quality water and concentrated H2SO4 from spent sulfuric acid leach solution where solvent extraction could then be applied to recover the sulfuric acid and metals. While HCl can be recovered for reuse using only DCMD.

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