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 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.

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.

Purpose. Research of the removal of arsenic by sulfiding from gold-arsenic containing concentrates of the Bakyrchik deposit. Methodology. To determine the composition of the samples, chemical and electron probe analysis were carried out; to determine the phase composition of materials, X-ray analysis was conducted. In order to predict the process of sulfidation of arsenic and its compounds in the range of 2982000 K, a thermodynamic analysis was performed. To establish the optimal conditions for the process of sulfiding arsenic and its compounds, studies were carried out to determine the effect of temperature and the consumption of elemental sulfur on the degree of sublimation of arsenic from gold-arsenic concentrate. The sulfiding roasting of the concentrate was carried out with elemental sulfur vapor coming from a new design evaporator with a mixture of gaseous nitrogen. Findings. The main minerals of the original concentrate are pyrite, marcasite, arsenopyrite, native gold and silver. Significant elements in the concentrate are, %: arsenic 2.93.1, iron 707.3, gold 40. It has been calculated by thermodynamic analysis that when the main minerals of gold-arsenic containing refractory ores and concentrates interact with sulfur in a neutral environment and in the range of 5001000 C, reactions of formation and removal of arsenic in the form of sulfides As2S3 and As4S4 occur. When a new design evaporator supplies elemental sulfur in a mixture with neutral gas and with an increase in firing temperature from 700 to 850 C at S : As = 0.35 : 1, the degree of sublimation of arsenic increases from 94.7 to 98.2%, with FeS2 : As = 1.3:1 from 94.0 to 99.5%. With an increase in the consumption of elemental sulfur vapor (with an increase in the S : As ratio from 0.35:1 to 0.6 : 1 and a temperature from 700 to 800 C), the degree of sublimation of arsenic from the gold-arsenic product reaches up to 99%. The condensed sublimes contained up to 98.599% As4S4 and As2S3, the dust caught in cyclones is close in its composition to the composition of cinder. Originality. A new technology for the removal of arsenic from gold-arsenic containing concentrates in an oxygen-free atmosphere in the temperature range of 700850 C with the removal and capture of arsenic sulfides up to 100% is proposed. The regularity of the degree of sulfidation of arsenic and its oxidized compounds by elemental sulfur vapors in a mixture with a neutral gas to As4S4 and As2S3 has been established. Practical value. The use of the new technology makes it possible to completely convert arsenic into sulfide forms which are environmentally friendly, convenient for storage, burial, or for use as antiseptics. The development can be used for processing arsenic-containing polymetallic ore materials.

The problem of processing stale tailings is a global one, and the main task is the extraction of economically valuable metals. In Kazakhstan, the market for the extraction of nickel and cobalt from stale tailings is practically undeveloped. In addition, the need for nickel and cobalt increases annually due to the high demand for nickel-cobalt batteries for the manufacture of electric vehicles, special alloys and others. Pyrite concentrate containing nickel-cobalt from Sokolovsko-Sarbaisky mining and processing plant is a valuable source of extraction of a number of valuable non-ferrous metals such as iron, nickel, cobalt, etc. The purpose of the study is to study the optimal conditions for the extraction of nickel and cobalt from thermally decomposed pyrite concentrate of the Sokolovsko-Sarbaisky mining and processing plant using sulfuric acid solutions. Thermodynamic analysis of oxidation reactions of the main components of pyrite concentrate showed that thermal decomposition of higher sulfides of iron, nickel and cobalt produced a series of non-stoichiometric lower sulfides Fe0.877S, FeS, Fe2S3, Fe7S8; Ni3S2, Ni3S4 and CoS0.89, CoS, respectively. The Pourbaix diagrams of Ni-S-H2O, Co-S-H2O and Fe-S-H2O systems show that sulfuric acid leaching of cobalt and nickel from thermally decomposed pyrite concentrate is possible at pH 0 - 1.5 and E > - 0.5 V. Leaching of non-stoichiometric FeS-Fe7S8 low iron sulfides is possible at pH 0 - 4.0 and E > 0 V. Studies to determine the optimum conditions of leaching of thermally treated pyrite concentrates found that for the extraction of nickel and cobalt effective concentration of sulfuric acid is 100 g/dm3, the leaching time is 120 minutes and temperature of 100°C and the maximum recovery of metals is 86.71% and 93.01%, respectively. Increasing the acid concentration, duration and temperature leads to complete dissolution of iron. A combined method for processing stale pyrite tailings can be used to process similar raw materials.