This paper presents the results of a study on the development of a processing technology for pyrite–cobalt concentrates to obtain iron oxide pigments (Fe₂O₃ and Fe₃O₄) via high-temperature hydrolysis. It was found that, in a single operation, the concentrate can be effectively purified from lead, zinc, and copper, yielding an iron–nickel–cobalt product suitable for further processing by standard technologies, such as smelting into ferronickel. The scientific originality of research concludes in a mechanism of stepwise selective chloride volatilization, which was established as follows: stage I (500–650 °C)—removal of lead; stage II (700–750 °C)—chlorination of copper and iron; stage III (850–900 °C)—volatilization of nickel and cobalt. Microprobe analysis of the powders obtained from high-temperature hydrolysis of FeCl₂·4H₂O and FeCl₃·6H₂O revealed the resulting Fe₃O₄ and Fe₂O₃ powders with particle sizes 50 μm and 100 μm. A visual color palette was created, corresponding to different Fe₃O₄/Fe₂O₃ ratios in the pigment composition—ranging from black (magnetite) to red (hematite)—and potential application areas. For the first time, the new technological scheme was proposed of pigments Fe₂O₃ and Fe₃O₄ production from pyrite–cobalt concentrates via combination of oxidized roasting with subsequent chlorination and high-temperature hydrolysis of the products.

A hierarchical surface that includes objects with different sizes, as a result of creating local fields, initiates a large number of effects. Micropores in the composition of macropores, as well as nanoclusters of the substance, were detected by scanning electron and atomic force microscopies on the surface of ZnO/Por-Si samples. An identical fractal dimension for all levels of the hierarchy was determined for these structures, which is associated with the same response to external excitation. Photoluminescence studies have shown the presence of localized levels in the band gap, with the probability of capturing both electrons and holes, which ensures charge transitions between energy bands. Decomposition of the electron paramagnetic resonance (EPR) signal into components made it possible to determine the manifestations of various types of interaction between paramagnetic particles, including the hyperfine structure of the spectrum. The ordering of the structure of the substance as a result of sequential annealing in the range from 300 to 500 °C was revealed in the EPR spectrum. This fact, as well as photo- and gas sensitivity for all types of samples studied, confirms the prospects of using these structures as sensors.

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.

В работе представлен термодинамический анализ хлоридовозгонки пиритно-кобальтовых концентратов в широком интервале температур с целью прогнозирования селективности хлорирования основных металлов. На основе расчетов ΔG°, ΔH°, ΔS° и logK для ключевых реакций установлены температурные области формирования летучих хлоридов Pb и Cu, а также сохранения оксидной формы Fe, Ni и Co. Построены температурные зависимости термодинамических параметров и карта стабильности оксидно-хлоридных фаз. Показано, что переход Pb в газофазные хлориды начинфается при 500–650 °C, меди – при 700–800 °C, тогда как железо, никель и кобальт сохраняют устойчивость вплоть до 900 °C и выше. Полученные результаты позволяют обосновать оптимальные температурные режимы хлоридовозгонки и прогнозировать селективность процесса при переработке пиритно-кобальтового сырья Бұл жұмыста пиритті-кобальтты концентраттарды хлоридті айдау процесінің термодинамикалық талдауы ұсынылған. Негізгі металдардың хлорлану селективтілігін болжау мақсатында негізгі реакциялар үшін ΔG°, ΔH°, ΔS° және logK мәндері есептеліп, олардың температуралық өзгерістері анықталды. Pb мен Cu хлоридтерінің 500–650 °C аралығында, мыс хлоридінің 700–800 °C температурада түзілуі басым екені көрсетілді. Fe, Ni және Co оксидтік түрінде 900 °C және одан жоғары температураларда тұрақты болып қалады. Оксидті-хлоридті фазалардың тұрақтылық картасы құрылып, процестің үш температуралық аймағы анықталды. Алынған нәтижелер пиритті-кобальтты шикізатты өңдеудің тиімді режимдерін негіздеуге және хлоридті айдау процесінің селективтілігін болжауға мүмкіндік береді This study presents a thermodynamic assessment of the chloride volatilization of pyrite-cobalt concentrates aimed at predicting the selective chlorination behavior of major metals. Temperature-dependent values of ΔG°, ΔH°, ΔS° and logK were calculated for key reactions, enabling the identification of temperature intervals responsible for the formation of volatile chlorides of Pb and Cu, as well as the persistence of Fe, Ni and Co in oxide form. Temperature trends of the thermodynamic parameters and a stability map of oxide-chloride phases were constructed. The results show that Pb begin forming gaseous chlorides at 500–650 °C, while Cu becomes reactive at 700–800 °C. Fe, Ni and Co remain thermodynamically stable as oxides up to 900 °C and above. These findings allow defining optimal temperature regimes and predicting the selectivity of the chloride volatilization process for pyrite-cobalt feed materials