Purpose. Predicting the formation of a stress-strain state (SSS) in the rock mass within the boundaries of influence of stope operations on the horizon -480 m in axes 2028 at the 10th Anniversary of Kazakhstans Independence (DNK) Mine. Methodology. An engineering-geological data on the host rocks properties are analyzed based on the international ISRM standard. Numerical modelling of the rock mass stress-strain state and the calculation of the load-bearing capacity of the compound support (roof-bolt+shotcrete+mesh) and arch support used at the mine are performed with the help of the RS2 software. This program, based on the Finite Element Method in a two-dimensional formulation, makes it possible to take into account a significant number of factors influencing the rock mass state. Findings. The calculations performed indicate that the support resistance is incommensurably low in comparison with the values of the initial stress field components in the rock mass. In such conditions, it may be more effective to strengthen the mass in the vicinity of mine working than setting more frames or using more massive support profiles. Originality. The paper presents the results of mathematical modeling and calculation of the stress-strain state of the underground supporting aquifer rock mass structures developed for complex mining-and-geological and geomechanical conditions of driving, supporting and operating mine workings on deep horizons of the mines at Donskoy Ore Mining and Processing Plant. Based on the performed research, the preliminary (advanced) strengthening of the border rock mass in the zone of inelastic (destructive) deformations has been substantiated, as a priority method to control the stability of mine workings. Practical value. The research results can be used when creating a geomechanical model of the field and designing stable parameters of mine working support.

Due to the sharp increase in demand and prices for nickel and cobalt, the search for new sources of raw materials has become a pressing issue. This study presents a comprehensive thermodynamic and kinetic analysis of the combined method of oxygen-deficient oxidative roasting and subsequent acid leaching to extract nickel and cobalt from pyrite waste sourced from Kazakhstani enterprises. The thermodynamic analysis showed that, under oxygen deficiency, thermal decomposition of higher sulfides forms non-stoichiometric, soluble lower sulfides of iron, nickel, and cobalt. The kinetic study revealed that the process is complex and multi-stage, and that it proceeds at a high rate in the 610–680 °C range, where kinetic factors control it. Activation energies were calculated for three stages: 105–115 kJ/mol for Stage I (450–479.3 °C), 310–320 kJ/mol for Stage II (661.8 °C), and 390–420 kJ/mol for Stage III (749.7–789 °C). Experimental studies confirmed the effectiveness of roasting at 700 °C for 60 minutes. Subsequent sulfuric acid leaching of the obtained sinders under optimal conditions (sulfuric acid excess coefficient R of 1.5 times the stoichiometric amount, temperature of 100 °C, and a duration of 2 hours) yielded high metal recoveries: 94.5% Fe, 93.4% Ni, and 91% Co. The developed technology, combining thermal activation and leaching, proved effective and is recommended for processing similar raw materials.

Selective Ni(II) recovery from polymetallic sulfate leachates is challenging because of competition from accompanying metal ions, particularly Mg(II). This study systematically evaluated selective Ni(II) recovery using commercial chelating ion-exchange resins and assessed their adsorption performance and regeneration behavior in the context of their integration into a conceptual flowsheet for oxidized nickel ore processing. The ore was characterized by XRF, XRD, and SEM–EDS, while Seplite LSC 495 (bispicolylamine) and Seplite LSC 773 (iminodiacetate) were evaluated using selectivity tests, kinetic and equilibrium studies, FTIR spectroscopy, and adsorption–desorption experiments. Both resins exhibited high selectivity for Ni(II) over Co(II) and Mg(II). Under the optimized conditions, Seplite LSC 773 achieved 99.36 ± 0.08% Ni(II) recovery from the model solution and 98.59 ± 0.36% from the actual leach solution, whereas Seplite LSC 495 achieved 94.62 ± 0.21% and 94.23 ± 0.21%, respectively. The equilibrium data exhibited a Giles S-type profile without reaching a distinct saturation plateau within the investigated concentration range, and the Freundlich model provided the most appropriate description of the data, consistent with adsorption on energetically heterogeneous binding sites. FTIR spectral changes indicated the involvement of the chelating functional groups in Ni(II) binding. Among the regeneration conditions investigated, 20 wt.% H₂SO₄ provided the highest Ni(II) desorption efficiency; however, desorption remained limited to approximately 42%, indicating that regeneration remains a major constraint on practical application. The experimental findings were incorporated into a conceptual flowsheet integrating sulfuric acid leaching, selective Ni recovery, subsequent Co separation, and MgSO₄·7H₂O production. Further work should focus on optimizing regeneration, extending cyclic testing, evaluating continuous-flow operation, and validating the integrated process at the pilot scale.

В связи с ростом спроса на никель и кобальт для литий-ионных аккумуляторов электротранспорта возрастает интерес к освоению новых источников сырья, включая техногенные отвалы. Объектом исследования являлась латеритная руда месторождения Кемпирсай, в которой никель и кобальт представлены преимущественно в оксидной форме. Цель работы – изучение извлечения металлов с применением комбинированной технологии, включающей сульфатизирующий обжиг и последующее водное выщелачивание. Оптимальные условия обжига: 30 мас. % серной кислоты, температура 500 °C и продолжительность 60 мин. В результате выщелачивания получен продуктивный раствор с содержанием (г/л): Ni 2,33; Co 0,67; Fe 18,5. Для дальнейшей переработки рекомендованы осаждение железа и селективное разделение никеля и кобальта методом экстракции Электрқозғалтқыш аккумуляторларын өндіруде никель мен кобальтқа сұраныстың артуына байланысты, соның ішінде техногендік үйінділерді қоса алғанда, жаңа кен көздерін игеруге қызығушылық артты. Зерттеу нысаны Кемпірсай кен орнының латеритті кені болып табылады, онда никель мен кобальт оксидтік түрде кездеседі. Жұмыстың мақсаты – металдарды біріктірілген әдіспен, яғни сульфаттандырушы күйдіру және кейінгі сулы шаймалау арқылы алу үдерісін зерттеу. Күйдірудің оңтайлы шарттары: күкірт қышқылын 30% (массалық) қосу, температура 500 °C және ұзақтығы 60 минут. Күйдірме өнімін шаймалау нәтижесінде құрамында (г/л): 2,33 Ni, 0,67 Co және 18,5 Fe бар өнімді ерітінді алынды. Ерітіндіні әрі қарай өңдеу үшін темірді химиялық тұндыру және никель мен кобальтты сұйық экстракция әдісімен селективті бөлу ұсынылады Due to the increasing demand for nickel and cobalt for lithium-ion batteries used in electric vehicles, interest in the development of new raw material sources, including technogenic dumps, has grown. The object of this study was lateritic ore from the Kempirsai deposit, in which nickel and cobalt are predominantly present in oxide form. The aim of the work was to investigate metal recovery using a combined processing route comprising sulfation roasting followed by water leaching. The optimal roasting conditions were 30 wt. % sulfuric acid addition, a temperature of 500 °C, and a roasting time of 60 min. Leaching resulted in a pregnant solution containing (g/L): 2.33 Ni, 0.67 Co, and 18.5 Fe. For further processing, iron precipitation and selective separation of nickel and cobalt by solvent extraction are recommended