A new solvent impregnated sorbent containing trioctylphosphine oxide was prepared using carriers from mesoporous silica, obtained by hydrometallurgical processing of Kola Mining-Metallurgical Company (Kola MMC, Russia) dump slag waste. The characterization of sorbent was performed using the SEM, FTIR and TGA techniques. Under static conditions, an sorption of rhenium onto impregnated sorbent in sulfuric acid solution was studied in a batch system with respect to contact time, sulfuric acid concentration, solid to liquid ratio and initial rhenium concentration. The recovery of rhenium from a sulfuric acid wash solution of the Kola MMC was demonstrated.

This work proposes an environmentally safe and economically feasible method of waste copper-nickel production slag utilization (Kola Mining-Metallurgical Company, Nornickel, Kola Peninsula, Russia). This process involves the decomposition of slag by diluted solutions of sulfuric acid (7–10 wt.% H₂SO₄) with a transfer in a solution of more than 70% silicon, 77% iron and 78% magnesium, and a concentration of non-ferrous metals in the residue (~70%). Copper ions were used in the leaching stage to prevent the release of hydrogen sulfide into the working atmosphere. Dehydration of the solution, followed by washing of water-soluble sulphates from silica, was carried out to separate silica from the leaching solution. The dehydration temperature effect on the silica structural characteristics was determined. The possibility of recovering non-ferrous metals from solutions after silica extraction by precipitation, in the form of copper cementite, and the sum of nickel and cobalt sulfides, was evaluated. Pigment-grade iron dioxide, magnesium sulphate and aluminium hydroxide were obtained by dehydration of the solution after extraction of base metals, calcination and other operations. Sulfuric acid leaching resulted in the disclosure of sulfide grains encapsulated in ferrosilicate, which is a favorable factor for flotation. The depleted residue can be successfully used in the construction industry.

The mutual solubility of components in the extraction system HCl-monohydric aliphatic alcohol ROH (R = C₅–C₁₀)-H₂O at 20°C was studied.

The possibility of hydrometallurgical processing of converter slag from nickel production aimed at integrated use of mineral raw materials and environmental protection is shown. The scheme of hydrometallurgical processing of slag using hydrochloric acid is proposed. The method involves leaching the slag with hydrochloric acid in the presence of ferric ions. The high values of iron and nonferrous metals extraction into the leaching solution are achieved during hydrochloric acid leaching. Silicon is concentrated in an insoluble residue. Liquid extraction was used to extract iron from hydrochloric acid leaching solutions. Silica-containing residues can be successfully used in the construction industry.