The complex electrochemical processing in sulfuric acid solutions of technogenic wastes of renium-containing heatresistant nickel alloys (HRNA) in the form of rather large scrap pieces of turbine blades has been studied. It was found that anodic dissolution of large waste pieces of rhenium-containing HRNA can be successfully carried out in sulfuric acid solutions (100 g/dm3) with addition of nitric acid (20 g/dm3) under direct current with a current density of 500–1000 A/m2 and a temperature of 30–40 oC without preliminary preparation. As much as 80–90% of rhenium, 90–95% of nickel, cobalt, chromium and aluminum pass into solution under these conditions. Almost all refractory rare metals (tungsten, tantalum, hafnium) pass into the anode slime almost completely. Rhenium, nickel and cobalt remaining in the anode slime were converted into solution by chemical slime treatment in a 2 M sulfuric acid solution with the nitric acid additives. Rhenium in the form of crude ammonium perrhenate, where rhenium content is not less than 68.9 wt.%, has been recovered from the combined solution after anodic treatment of alloy wastes and chemical dissolution of anode slimes by a known solvent extraction method. The cake, remaining after chemical treatment of anode slimes, is a concentrate of refractory rare metals containing, wt.%: up to 39–42 W; 15–18 Ta; 3–4 Hf. According to X-ray fluorescence (XRF) analysis, the cake base is tungsten trioxide. Following rhenium extraction, the sulphate raffinate, containing significant amounts of nickel, cobalt, chromium, aluminum and some other metals, has been neutralized with alkali which allowed to precipitate hydroxides of these metals into a nickel-cobalt concentrate which aincludes 37.55% Ni and 4.48% Co. Roasting of nickel-cobalt concentrates obtained from the products of the HRNA waste electrochemical treatment at a temperatures of up to 400 oC will allow one to converte all nonferrous metal hydroxides into oxides, reduce the mass of concentrates by 15–20%. The process flowsheet of complex processing of large-scale waste of renium-containing HRNA is proposed. The technology was successfully tested within the pilot project at the enterprise of RSE “Zhezkazganredmet”, which is an internationally known manufacturer of ammonium perrhenate.The work was carried out with the financial support of the Committee of Science of the Ministry of Education and Science of the Republic of Kazakhstan under the Target financing program (project No. BR05236406).

Samples of gel-type cation exchangers of the TOKEM nomenclature were tested for lithium extraction from multicomponent natural brines. The dependencies of the extraction of Li and other impurities—Na, Ca, and Mg—on the duration of the sorption process for the tested ion-exchange resins under static conditions are presented. Metal ions can be arranged according to the degree of extraction for each ion exchanger in a row: Ca²⁺ < Mg²⁺ < Li⁺, Na⁺. Testing of ion exchangers under static conditions on technological Li-containing solutions confirms the applicability of TOKEM-140 and TOKEM-160 cation exchangers for lithium extraction. For TOKEM-140, lithium extraction over time varies from 76.2% to 73.8% and for TOKEM-160—from 73.8% to 72.4%. The ionic background of natural brines has a significant effect on the capacity of ion exchangers for lithium and forms the following series Li⁺ << Mg²⁺ < Ca²⁺ << Na⁺ relative to the obtained concentrations of metal ions in natural brine. The overlay of IR spectra of TOKEM-140 and TOKEM-160 ion exchangers before and after saturation shows slight changes in their appearance, indicating that the lithium sorption process has occurred. The values of static exchange capacity (SEC) for TOKEM-140 and TOKEM-160 cation exchangers are identical.

Research analysis reveals factors influencing third-phase crud formation and composition during metal extraction, including solution composition, solid suspensions, organic compounds, colloidal compounds (e.g., silicic acid), and extractant purity. Compositional analysis of copper-containing sulfuric acid solutions (1.25 g/dm³ copper) identifies principal sulfate-forming components. Copper extraction was studied using extractants LIX 984N, ACORGA M5774, and M5640 at different ratios of the organic phase to the aqueous O:A (from 1:2 to 1:10). Suppressive impact of 10 vol.% CR60 additive on third-phase crud formation during copper extraction with LIX 984N, ACORGA M5774, and M5640 is analyzed, with ACORGA M5774 being the most effective. Physicochemical analysis characterizes CR60’s active substance as poly(sodium 4-styrenesulfonate) with steel-suppression properties, and its structural formula is determined. Optimal copper extraction conditions establish ACORGA M5640’s 24% efficiency, followed by ACORGA M5774 at 15%. CR60 reduces crud formation, with 5 cm³ of ACORGA CR60 added to sulfuric acid solution reducing interfacial crud formation by 2–3 times. Optimal extraction parameters include 1:2 O:A ratio, 20 ± 5 °C temperature, 5 cm³ CR60 additive, 5 min process duration, and 1-day settling time. ACORGA M5774 (10 vol.% in kerosene) is recommended as an extractant, with 2–3 stages of countercurrent extraction.

This paper examines the process of selenium precipitation from the slime generated by the sulphuric acid plant of the Balkhash Copper Smelter. Contrary to similar tailings generated by non-ferrous metals industry, such slime has a high concentration of selenium (12.5–4.6 wt. %). By utilizing it in the production process, one can raise the output of selenium by more than 30% compared with the amount of selenium recovered by the smelter from copper anode slimes. The slime that was used in the experiments had been separated from the slurry produced as a result of scrubbing of metallurgical gases generated by copper smelting and matte converting processes. The slime was rinsed with water to remove sulphuric acid from it and then dried at 105 oC. With the help of new-generation analytical equipment, the slime was analyzed for qualitative, quantitative and material compositions. 15 elements with significantly varying concentrations were detected. The main components include lead (51.17 wt. %) and selenium (12.49 wt. %), which are present in the form of lead sulphates and elemental selenium. Other lead and mercury compounds are also present as disseminations – i.e. different salts of selenium acids. Considering the forms in which lead and selenium are mainly found in the slime, lead was initially converted into carbonates by sodium carbonate leaching, and then nitric acid was used to make lead transfer from the cake into the solution. The authors looked at the effect produced by the sodium carbonate concentration (50–200 g/dm3), solid-to-liquid ratio (1:(2–6)), process duration (20–120 min) and temperature (20–70 oC) at constant slime feed and stirrer RPM on the behaviour of lead and selenium. Optimum conditions were identified in which both elements almost completely remain in the carbonate cake, and only 0.019% Pb and 0.17% Se get extracted into the solution. Different quantities of three carbonate-containing compounds of lead and seven selenium compounds were found in the cake. When the carbonate cake is leached with nitric acid, almost all of the lead transfer to the solution, while selenium remains in the cake as an elementary substance and mercury selenides. As compared with the slime, the concentration of selenium in the cake increased by 5.6 times. This research was funded by the Science Board of the Ministry of Science and Education of the Republic of Kazakhstan under the following programme: Development and Implementation of Innovative Technology Ensuring a Higher Recovery of Non-Ferrous, Noble, Rare and Rare Earth Metals, as well as Fulfillment of Production Targets by Industrial Companies of the Republic of Kazakhstan Set for 2018–2020.