This paper presents the results of research on the method of utilization of self-disintegrating slags of refined ferrochrome production by autoclave carbonization in carbon dioxide environment. The work has a complex character, including earlier laboratory studies of the slag carbonization process under different conditions, as well as studies of chemical and mineralogical composition of initial waste slags taken from the slag dump and samples of bricks subjected to carbonization. The composition of slags and obtained products was investigated by XRD, DTA, DTG and XRF analyses, which showed that the main phases of the studied samples are dicalcium silicate, montichelite, periclase, magnesiochromite, calcite. Thermal analytical studies showed that magnesium carbonate is present only in the samples of artificially carbonized material. Also, the process of carbonate formation in the thickness of bricks during forced carbonization was investigated. As a result, it was obtained that with increasing CO₂ pressure, the amount of bound carbon in the products increases proportionally in all layers. It was determined that the amount of CO₂ absorbed during carbonization can reach 20 % of the mass of the initial slag. Stale slag can be used simultaneously as a carbon dioxide absorber and as a building product.

The article presents the results of obtaining a composite material by sintering nickel-containing raw materials mixed with carbon-containing materials, namely using coke and semi-coke. The sintering process was performed at a charge layer height of 240 mm and the temperature of the lower layer was T = 1200 °C. The results of the sieve analysis showed (a fraction of 10 mm) that the yield of a suitable composite material using coke was 68.3% and with semi-coke 67.0%. The average nickel and chromium content in the composite materials was 1.42% and 3.07%, accordingly. As a result of determining the strength characteristics of the obtained composite materials with various reducing agents by dropping from a height of 2 m onto a steel pallet, it was found that the obtained composite materials have high mechanical properties in terms of strength of 81% and 89.2%. The results of the elemental composition at the studied points and the thermal analysis of the studied composite material are presented. The mineralogical composition of the composite material is presented in the form of serpentine and nontronite, and the empty rock is made of quartz and talc. The activation energy of thermal analysis by the method of non-isothermal kinetics were calculated. The results of experiments on the production of composite materials from nickel-containing raw materials will be recommended for obtaining the optimal composition of composite materials at the stage of pilot tests and industrial development of the developed technology for processing nickel ores of the Republic of Kazakhstan. For the processing of nickel-poor nickel ores, it is of great importance to obtain optimal technological and technical and economic indicators that ensure low cost of nickel in the resulting product.

The article provides a brief overview of technologies and methods for processing dispersed metallic waste generated during ferroalloy production, including high-carbon ferrochrome (HCFeCr). It is noted that the most cost-effective and rational method for reusing metallic dust is briquetting. Considering the development of briquetting technologies, as well as the latest equipment and binder materials involved in this process, aspiration dust from ferrochrome crushing can be fully utilized in metallurgical recycling. To verify this assumption, laboratory studies were conducted using polymer-based binders and liquid glass as a baseline option. The methodology of briquetting using both laboratory and industrial presses is described, along with an assessment of the mechanical properties of the briquettes. The studies indicate that the introduction of an inert filler (gas-cleaning dust) into the metallic dust composition improves the briquetting ability of the mixture by enhancing adhesion between metal particles and the binder. The obtained industrial briquette samples exhibit high mechanical strength, ensuring their further use in metallurgical processing. The study concludes that semi-dry briquetting using hydraulic vibropresses is a promising approach for the utilization of dispersed ferroalloy waste.

This article presents the results of laboratory studies on the smelting of nickel–chromium-containing ferroalloys from low-grade nickel ores from Kazakhstan. X-ray phase analysis was performed on raw materials, which included quartz, nontronite, chromium metahydroxide, goethite, magnetite, iron chromite, and nickel (II) silicate. The reduction reactions of metal oxides with carbon and carbon monoxide were studied as the temperature increased. Experimental smelting was carried out in a Tammann furnace at 1500–1550 °C using three types of reducing agent: RK coke, as well as its mixtures with low-ash Shubarkol coal, in ratios of 75:25 and 50:50. The second option demonstrated the highest economic efficiency, achieving a 91% nickel recovery rate, reduced coke consumption, and a slag-to-metal ratio of 3.07. Chemical analysis showed that the nickel content in the obtained alloys ranged from 2.5% to 6.5%, while chromium content ranged from 2.6% to 4.5%. X-ray phase analysis confirmed the presence of Fe₂Ni_0.6Si, Fe₅Si₃, and Fe₂CrSi phases in the alloy structure. Local element concentrations varied within the following ranges: Fe—55–59%, Ni—2–10%, Cr—2–7%, and Si—29–35%. The results of this study confirmed the feasibility of producing a nickel–chromium-containing alloy with a nickel content of 2–10% and a chromium content of 2–7%.

This study presents the results of laboratory experiments on the processing of lateritic nickel ores mixed with coal and CaO, followed by the use of the obtained product for the smelting of nickel-containing ferroalloy by the metallothermic method. The study analyzed the thermodynamic effects of complex reductant concentration (silicon- and aluminum-containing alloy) on the reduction degree of nickel and iron. An experimental process resulted in a product containing Ni_total (2.60%) and Fe_total (60.52%), obtained through reduction roasting of lateritic nickel ore mixed with coal and an addition of 20 g of CaO at a temperature of 1150 °C. Under laboratory conditions, a nickel-containing ferroalloy was successfully obtained using the product after reduction roasting and a complex alloy as the reducing agent. The following optimal process parameters were determined: reductant consumption of 20 g per 100 g of the reduction roasting product, smelting temperature of 1600 °C, and slag basicity (CaO/SiO₂) of 0.5. In this case, a nickel-containing ferroalloy with 72% iron, 15% nickel, and up to 5% chromium was successfully obtained through silicon and aluminum reduction using a complex alloy. A microstructural analysis of the nickel-containing alloy was conducted using an electron probe microanalyzer (JXA-8230) in combination with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that silicon and iron were the dominant elements in all particles. Nickel was detected at concentrations of up to 15.02 wt. %, while chromium reached 3.47 wt. %. Depending on the silicon concentration, the nickel-containing ferroalloy is recommended for corrosion-resistant steel production (Si < 5%) and as a reducing agent for ferronickel production (Si > 5%).

This study presents the results of the solid-state reduction of iron–manganese ore from the Keregetas deposit (Kazakhstan) using hydrogen as a reductant. The findings demonstrate that hydrogen is an effective and environmentally friendly reducing agent, enabling selective reduction of iron. The investigated iron–manganese ore exhibits a complex mineralogical composition comprising oxides of Fe, Mn, Si, and aluminosilicate complex phases. X-ray diffraction (XRD) analysis of the raw ore confirmed the presence of goethite, hematite, quartzite, and MnO2 as the primary mineral phases. Oxidative roasting induced the dehydration of goethite and its conversion to hematite, along with the formation of Mn2O3 and Mn3O4 phases. The detection of Mn7SiO12 indicates interaction between manganese and silica under high-temperature oxidation conditions. Reduction experiments were conducted in an RB Automazione MM 6000 laboratory furnace at temperatures ranging from 700 to 1100 °C, with a holding time of 60 min and a hydrogen flow rate of 0.5 L/min. Results revealed high selectivity of hydrogen reduction: at 700–800 °C, iron and arsenic were predominantly reduced, as evidenced by the emergence of a metallic Fe-containing phase, while oxides of Mn, Si, Ba, and Al remained in the residue. Increasing the temperature to 900–1000 °C resulted in partial reduction of manganese. At 1100 °C, a decrease in the intensity of the metallic phase was observed, likely due to sintering of ore particles and reduced gas permeability. The reduced metal and oxides were readily separable by melting. These findings provide a basis for developing processing schemes for beneficiation and hydrometallurgical treatment of iron–manganese ores from Kazakhstan.