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 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.

In this work, we investigate V(V) sorption on amorphous and modified silica. Silicon dioxide was obtained from the metallurgical slag. The impact of modification on vanadium sorption was studied. The surface was modified with hydrazides (HDs) and dimethylhydrazides (DMHDs) of the tertiary carbonic Versatic acids CH₃R₁R₂CC(O)OH of the C_10–19 fractions. The optimal sorption conditions on the unmodified sorbent were pH 4, 1 h, and 40 °C. The sorption capacity of V(V) ions increased with surface modification. For modified sorbents, the range of action shifted to a more acidic area (2.0–3.0), where the HV₁₀O₂₈⁵⁻ polyanion formed a complex with N′,N′-dimethylhydrazide groups. When studying the kinetics of the V(V) sorption process on silica samples, the optimum time of adsorption equilibrium establishment (10 min) and reaction mechanism were determined. The sorption process was significantly accelerated by surface modification. The vanadium sorption process is described by pseudo-second-order kinetics. The study of adsorption isotherms revealed that the vanadium sorption isotherm corresponds to the Langmuir equation. The differences in the extraction of vanadium ions are explained by different sorption mechanisms, which are associated with the variety of vanadium forms in the solution.

In the production of abrasive materials from metallurgical slags, fine waste with a size of less than 40 microns is produced, which contains valuable components. Unlike slag, this waste does not need to be pulverized for processing, which greatly simplifies the process. However, without silica extraction, it is impractical to carry out waste treatment. The authors of the work considered the possibility of obtaining silicon dioxide from abrasive wastes of Rezh, Orsk and Kyshtym, containing up to 20,7 % of silicon, up to 31,7 % of iron and up to 0,7 % of the sum of nickel and copper. Sulfuric acid treatment of waste produced a solution containing magnesium and iron (II) sulfates and silicic acid. It was found that during processing of Orsk wastes the degree of components extraction is significantly lower in comparison with Rezh and Kyshtym wastes 24,5, 67,8 and 59,3, respectively. The obtained solution is used to produce silica powders by dehydrating it. The dried mixture is subjected to aqueous washing of metal sulfates. As a result, samples with high specific surface area in the range of 387,6 to 841,5 m2/g were obtained. The average pore size is 2,3–3 nm, which allows us to attribute these silicas to mesoporous silica. SiO2 content in the samples reaches up to 98 %. Samples of silicon dioxide from abrasive materials were compared with that obtained from metallurgical slag of Pechenganickel Combine and have similar parameters. The obtained insoluble leaching residue contains concentrate of non-ferrous metals and according to X-ray data it consists of calcium sulfate, so after separation of non-ferrous metals it can be used in construction industry.

Possible applications of silicon dioxide obtained from metallurgical slags of JSC “Kola MMC” are considered. The possibility of using silica in the construction industry as an additive to cements and as a sorbent for sorption of niobium is shown.

The results of the recovery of zinc by sorption on ion-exchange resins from solutions formed at various stages of purification of nickel chloride solutions of Kola MMC are presented. The opportunity of using anion-exchange resin АМП-п and cation-exchange resin Ку-2-8 for the recovery of zinc from the reextract, as well as the use of resin AMП-п in the scheme of cake processing hydrolytic purification of the reextract, are shown.