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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. [ABSTRACT FROM AUTHOR]

The article presents studies on the extraction of iron from chloride solutions with aliphatic alcohols, ketones, and their mixtures. Dilution of 1-octanol with an inert aromatic diluent to a concentration of 80 vol.% led to an increase in its extraction capacity, while the extraction capacity of 2-octanone has decreased with dilution. A synergistic effect was found for a 1-octanol/2-octanone mixture, the maximum of extraction was observed at a ketone concentration of 80 vol.%. The effect of a mixture composition and chloride ion concentration on the iron extraction degree was studied. McCabe-Thiele results indicated that at Fe(III) concentration in the aqueous phase 9.32 g∙dm−3, it is possible to extract iron(III) quantitatively using a mixture of alcohols C8+C10 (70 vol.%) and 2-undecanone (30 vol.%) after three extraction stages. Stripping of Fe(III) from the mixture was done with distilled water. After the stripping, the loaded Fe(III) concentration in the organic phase was reduced from 27 g∙dm−3 to <0.001 g∙dm−3 for 3 stages. The conditions were tested in continuous mode at a cascade of laboratory extractors. During the tests on the cascade, the low solubility of the mixture of ketone with alcohol was established, and the concentrated solution of ferric chloride was obtained. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]