In recent years, there has been an increased demand for nickel-cobalt-containing batteries, which in turn adds a lot of interest in the production of these metals in large volumes. Due to a contraction of the volume of nickel sulfide ores, the majority of producers consider laterite deposits as a potential source of nickel and cobalt. However, processing laterites by traditional pyrometallurgical methods is economically unprofitable. Research has shown that the use of combined and hydrometallurgical methods can be promising. This article is devoted to a review of the results of research and articles on the extraction of nickel and cobalt from laterite ores over the past 20 years. Current technological schemes for the production of nickel and cobalt using combined manufacturing processes are presented, as well as the results of scientific research on increasing the recovery degree of nickel and cobalt from low-grade refractory laterite ores using preliminary activating roasting, various leaching reagents, oxidizing agents, bacteria, etc. Growing interest in nickel production has also been observed in Kazakhstan and research work on the extraction of target metals from local laterite ores is being intensively carried out. According to the investors’ forecast, the first mining in the republic and full commissioning of nickel production are expected in 2025. This study was funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (grant no. AP19680477).

The development of combined enrichment technologies becomes more significant due to the decreasing of the processed ores quality and involvement in the processing of poor, refractory ores. The difficulty in the flotation enrichment of mixed and oxidized polymetallic ores and intermediate products lies in the effective sulfidization of the surface of oxidized minerals. The sodium sulfide reagent used in flotation does not always provide complete sulfidization of the mineral surface. On the intermediate product of lead-zinc ores related to the phase composition of mixed ores, flotation studies were carried out on the original product and after preliminary sulfidization by the pyro-metallurgical method. It was found that in the pre-sulfidizied product, the extraction of zinc increased to 17.23 %, and lead to 10.07 %, compared with the original product without pre-treatment.

The article discusses the methods of processing vanadium-containing raw materials, including methods of pre-sintering and leaching of raw materials, extraction and precipitation of vanadium-containing solutions. In addition, the specific methods used for each type of vanadium-containing raw materials are described, with a description of their advantages and limitations. The article also briefly analyzes a number of the main influencing factors and mechanisms of various processes. Some research prospects are proposed to improve the methods of vanadium concentration from vanadium-containing raw materials. The article considers the potential of extraction and processing of vanadium-containing black shale ore, as well as vanadium-containing titanomagnetite ores. Spent vanadium catalysts used in petrochemical processes can be a potential source for vanadium extraction. In addition, vanadium-containing bauxite raw materials, oil and steel production slags can be promising raw materials for further extraction of vanadium. The article presents methods for processing vanadium-containing raw materials, including methods of pre-sintering and leaching of raw materials, extraction and precipitation of vanadium-containing solutions. In addition, the specific methods used for each type of vanadium-containing raw materials are described, with a description of their advantages and limitations. The article also examines the potential of extraction and processing of vanadium-containing black shale ore, vanadium-containing titanomagnetite ores as a potential source for vanadium extraction. Vanadium-containing bauxite raw materials and steelmaking slags can also be promising raw materials for further extraction of vanadium.

The treatment of spent drilling fluids generated during the drilling of technological wells for uranium production represents an important engineering and environmental challenge associated with high energy consumption, significant waste generation, and the need for rational water use under arid regional conditions. Conventional phase separation methods based on gravitational settling and chemical–mechanical treatment are characterized by limited process controllability, long processing times, and increased consumption of reagents and energy. This study proposes an energy-efficient and reliable hydrodynamic technology for the treatment of spent drilling fluids based on the formation of controlled turbulent structures without the use of mechanical drives. The research object comprised spent drilling fluids (SDFs) generated during the drilling of technological wells for uranium production in the southern regions of the Republic of Kazakhstan and the Kyzylorda region. Experimental investigations were carried out using a laboratory–pilot hydrodynamic disperser with variations in velocity gradient, treatment time, flocculant dosage, and suspension flow rate. A mathematical model linking hydrodynamic process parameters with phase separation kinetics and energy characteristics was developed. Model calibration by weighted nonlinear least squares yielded a stable parameter set with 95% confidence intervals, and model validation demonstrated good agreement between calculated and experimental data (MAPE 8.4%; maximum relative error 11.8%). It was established that the use of a hydrodynamic disperser provides separation efficiency of up to 90–95% under optimal operating conditions while reducing specific energy consumption and maintaining stable repeated-cycle performance within the investigated operating window. Experimental results confirm that implementation of the hydrodynamic technology enables a reduction in sludge volume by 40–60%, recovery of up to 60–80% of process water, and a significant decrease in waste requiring transportation and disposal. The obtained results demonstrate the high environmental and resource-saving efficiency of the proposed technology and its suitability for scaling and industrial implementation at facilities drilling technological wells for uranium production. The developed hydrodynamic approach can be considered an effective engineering platform for creating energy-efficient and sustainable systems for drilling fluid treatment in regions with limited water resources and remote industrial infrastructure.

This study explores the potential of oil sludge, a hazardous by-product of the oil industry, as a sustainable rejuvenator for restoring the physicochemical and rheological properties of aged bitumen. Aged binder samples were modified with different concentrations of oil sludge (1%, 3%, and 5%) and analyzed using dynamic shear rheometry (DSR), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The incorporation of 5% oil sludge increased penetration from 60 to 71 mm and the softening point from 55 °C to 72 °C, indicating enhanced flexibility. DSR measurements showed a ~10% decrease in complex modulus (G*) and a slight increase in phase angle, confirming partial rheological recovery. FTIR spectra revealed partial restoration of aliphatic and aromatic functional groups, with a decrease in sulfoxide absorption bands, while SEM analysis indicated improved homogeneity and reduced microcracking. TGA confirmed enhanced thermal behavior and a reduction in residual mass. The novelty of this work lies in the first-time application of regionally sourced oil sludge as a rejuvenator, evaluated through a multiscale analytical framework. These findings demonstrate the dual benefits of performance recovery and hazardous waste valorization, contributing to sustainable road maintenance within a circular economy approach.

The SX-EW technology is more effective for the production of copper from refractory oxidized ores for the present day. A wide range of modern extractants is currently offered on the market for the extraction of copper from leaching solutions and its choice is a very important issue in the production of copper using the SX-EW technology. The aim of this work was to study the extraction properties of modified extractants of the Acorga series (5747, 5910, 5640) and unmodified extractant Lix 984N. It has been established that extractants Acorga 5640 and unmodified Lix984 have high selectivity to copper. During the extraction of copper from the productive solution with the use of all extractants, the formation of a third phase, cruda, is observed. Physical and chemical studies have established that the steak contains a large amount of silica, magnetite, hematite and anglesite. The distribution of iron, silica, and copper ions during extraction was studied and it was found that the extractant Lix 984 N (10%), then Acorga5640 (10%), has a high selectivity to copper/iron and copper/silica. Acorga 5640 (10%) is an effective extractant of copper from the productive solution of the Almaly deposit. It is observed that the amount of crud formed during extraction also depends on the rate of phase mixing, the number of revolutions of the stirrer, at a speed of 350-450 rpm, the formation of crud is 0.73%. The addition of the Acorga CR60 reagent in the amount of 5-10 ppm leads to a 3-3.2-fold decrease in the volume of the crud. This study was funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan, № AP14871587.