In this paper, we study the possibility of obtaining iron and titanium-vanadium concentrates with highest contents of iron and titanium, respectively, through hydrometallurgical processing of the titanomagnetite ores of the Chineisk deposit. We varied two key parameters to determine the efficiency of the process: (a) concentration of leaching solution (ammonium fluoride); and (b) acidity of solution. Ammonium fluoride concentration was varied from 0.08 mol/L to 4.2 mol/L with the other fixed parameters. It was shown that optimum ammonium fluoride concentration for leaching the ore is 0.42 mol/L; at these concentrations iron and titanium contents are about 62.8 wt % and 3.5 wt % in solid phase, respectively. The acidity of solution was changed by adding of hydrofluoric acid with varied concentration (from 0.86 mol/L to 4.07 mol/L) to ammonium fluoride solution with fixed concentration of 0.42 mol/L. The best results (degree of titanium extraction = 63.7%) were obtained when using a solution of hydrofluoric acid with concentration 4.07 mol/L. In this case, the addition of acid makes it possible to increase the Fe/Ti ratio by 3.4 times in comparison with the original ore. Thus, we conclude that acidity and the concentration of ammonium fluoride solution significantly influences the selectivity of the hydrometallurgical process.

The influence of the environment and bacterial cultures on the degree of gold leaching from Au-containing raw materials of different compositions, origins, and with different contents of gold, selected in the Ural Federal District (Russia), was determined. The leaching degree was determined according to the change of the gold concentration in the ore by means of mass-spectrometry with inductively-coupled plasma. It was demonstrated that the degree of Au bioleaching from carbonaceous-argillaceous slates, containing 2.17 g/t of gold, and from pyritic technogenic raw materials, containing 1.15 g/t, when holding them in peptone water and Leten medium reached 92.17% and 87.83%, respectively.

Techniques of stripping voltammetry (SV) determination of silver and gold in pyrites and carbonaceous matter are developed. The problem of quantitative transfer of the analytes into the solution is solved. For this purpose, the ore matrix of carbonaceous shales was decomposed by mineral acids in autoclaves at high pressures. The element to be determined from the sample matrix was separated by extraction. Ag(I) ions from the solutions were extracted in the form of a dithizonate complex in CCl₄. Au(III) ions were extracted by diethyl ether. The extracts were decomposed thermally. The dry residue was dissolved in the background electrolyte, and the element was determined by the SV method. The graphite electrode (GE) impregnated with polyethylene was used as a working electrode in the SV determination of silver. The SV determination of gold was carried out using a GE modified by bismuth. The limits of detection (LOD) of Ag(I) and Au(III) contents were equal to 0.016 mg L⁻¹ and 0.0086 mg L⁻¹, respectively. The results of SV determination of gold and silver in standard samples, pyrites, and carbonaceous shales were presented. The silver content in the pyrite was 13.6 g t⁻¹, and in carbon shale it was 0.34 g t⁻¹. The concentration of gold in the pyrite of the Kirovsko–Kryklinskaya ore zone was 1.15 g t⁻¹, while in carbonaceous shales it was 2.66 g t⁻¹. The obtained data were consistent with the data of atomic emission spectroscopy (AES) and inductively-coupled plasma mass spectrometry (ICP–MS). The error of determination of elements by stripping voltammetry was calculated as ranging from 10 to 6 g t⁻¹ (less than 12%) in pyrite and carbonaceous material when determining the silver content, and from 1 to 3 g t⁻¹ (less than 22%) when determining the gold content in pyrite and carbonaceous matter.

The possibility of enrichment and radioactivity reduction of zirconium concentrate obtained at the Obukhovsky mining and processing plant, located in the North Kazakhstan region, was investigated. The zircon concentrate was enriched and deactivated by dry magnetic separation and centrifugal air separation. The elements distribution over the grain surface of the obtained fractions was studied and the particle size distribution was determined by energy dispersive X-ray spectroscopy. The characteristics of the initial zircon concentrate were determined. The average particle size was 70 µm, the bulk density was 2.21 g/cm³, the true density was 4.05 g/cm³, the activity was 10.3 ± 0.6 kBq/kg, and the ZrO2 content was 44.85 wt.%. Dry magnetic separation was carried out at a magnetic induction value of 1.3 T in the separator working area and a feed rate of 5 g/min. Centrifugal air separation was carried out using a rotary classifier at rotor speeds of 3000, 980, and 600 rpm, consuming 2000 Nm³ of air per hour and a concentrate flow of 20 kg/h. The scheme of zircon concentrate processing to produce three final products was proposed. The first is the zircon concentrate having a low activity (ZrO₂ content = 55.4 wt.%, P = 5.8 ± 0.6 kBq/kg). The second is the titanium-containing fraction having a low zirconium content (ZrO₂ content = 17.7 wt.%, P = 14.2 ± 0.6 kBq/kg). The third is the concentrate having a considerable zirconium content and high activity (ZrO₂ content = 23.5 wt.%, P = 12.8 ± 0.6 kBq/kg).

The present work analyzes the specimens of orthite (allanite) mineral ores obtained from the Vernadsky mine (Slyudyanka River, Irkutsk region) and Yuzhno-Bogatyrskoye occurrence (Kuznetsk Alatau). The elemental chemical composition of the ore was determined by electronic microscopy of the specimen’s surface. The study establishes that uranium and thorium in orthite ores of the Yuzhno-Bogatyrskoye occurrence are mainly represented by their separate minerals, while the content of the orthite phase in the form of their isomorphic inclusion is small.

The paper contains the results of hydrometallurgical processing of technogenic pyrite raw materials. The method is based on selective extraction of gold and silver from ore by solution, which contains sodium sulfite and sodium sulfate. The most promising results were obtained utilizing solution with sodium sulfite and sodium sulfate concentration of 25 g/L and leaching time – 1 hour. Under these conditions, the extraction of gold was 67%. The use of sodium sulphate and sodium sulfite allows to extract gold and partially silver from refractory sulfide ores.