Along with the growth in the production of metallurgical grade silicon and high-silicon ferrous alloys, there is a significant increase in the formation of microsilica, which is an ultra-fine technogenic waste. The direct application of microsilica in ore-thermal furnaces is hindered by low bulk density, poor gas permeability, and high dusting. This paper explores the thermophysical and microstructure properties of briquettes based on microsilica, which includes various types of carbonaceous reducing agents such as semi-coke and coal. For manufacturing, the liquid glass was used as the inorganic binder for the preparation of microsilica briquettes. The best variants were chosen based on strength tests carried out during preliminary studies. In the laboratory tests, the stability of the briquettes at elevated temperatures was evaluated. Samples were heated to 1000–1500 °C and subjected to impact testing. Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) was used to investigate the microstructure and local elemental distribution. It was revealed that the calcinated briquettes of the microsilica–semi-coke mixture have better thermal stability compared to the samples with coal and withstand the temperature range up to 1500 °C. The microstructure of the briquette from the microsilica-semi-coke mixture is characterized by the formation of a more uniform silicate matrix with the presence of a homogeneously distributed carbonaceous component. Coal-based samples show higher heterogeneity and porosity. Therefore, it can be stated that the selection of carbonaceous reductants is one of the key factors influencing the thermal stability of microsilica briquettes.

This study evaluates the effects of semi-industrial and synthetic Fe–Si–Mn–Al deoxidizers on the microstructure, non-metallic inclusions, and hardness of St3 steel. Seven complex alloys with different Fe, Si, Mn, and Al contents were produced and compared with conventional FeSi–FeMn–Al deoxidizers. The steel samples were examined by optical microscopy and Rockwell hardness testing. Depending on the deoxidizer composition, ferrite–pearlite, bainitic, martensitic, and structurally heterogeneous regions were observed. The measured hardness ranged from 26 to 47 HRC. Porosity and dendritic heterogeneity remained in several samples. The results demonstrate that the composition of an Fe-Si-Mn-Al deoxidizer is associated with differences in optically observed microstructural characteristics and reported hardness. These findings provide an experimental basis for selecting complex deoxidizer compositions for further steelmaking studies.

Silica–carbon briquettes enable the incorporation of fine-grained silica-bearing materials and carbonaceous reductants into the charge used for ferrosilicon smelting. This study examines the composition of the composite disclosed in Patent of the Republic of Kazakh-stan No. 38264, the results of X-ray diffraction analysis of the briquette, and the chemical composition of ferrosilicon samples sequentially collected during the experimental smelting campaign. According to the patent data, the composite contained 41.41% fixed carbon, while the ash content was 39.38% on a dry basis, and the SiO₂ content in the mineral fraction was 90–92%. The first addition of briquettes was recorded at tapping No. 17. However, the exact timing of the corresponding metal sample collection relative to briquette charging is unknown; therefore, this sample was excluded from the comparison between the two operating periods. In samples Nos. 10–16, the Si content ranged from 74.75 to 76.21 wt.%, whereas in samples Nos. 18–24, it ranged from 75.49 to 76.47 wt.%. The corresponding arithmetic mean values were 75.65 and 75.77 wt.%, respectively. Analysis of the X-ray diffraction pattern of metal sample No. 20 allowed two iron–silicon phases to be tentatively identified. A silicon content of approximately 75 wt.% had already been achieved before the introduction of the briquettes. Owing to the sequential nature of the smelting campaign and the absence of a directly comparable material balance, the independent effect of the briquettes on alloy composition, silicon recovery, or electrical energy consumption cannot be reliably established.

The production of refined ferrochrome is accompanied by the formation of self-disintegrating slags caused by the β→γ-Ca₂SiO₄ polymorphic transformation during cooling, resulting in environmental and technological problems. This study aimed to develop and validate a technology for long-term stabilization of refined ferrochrome slags using remelted and desulfurized borate ore (RDBO) from the Inder deposit as an alternative to colemanite. Thermodynamic modeling, X-ray diffraction (XRD), scanning electron microscopy (SEM), and pilot-industrial trials were conducted to evaluate phase transformations, microstructure formation, and slag stability. The results showed that the addition of boron oxide promoted the formation of stable borate phases, primarily CaB₄O₇, and reduced the content of unstable Ca₂SiO₄ phases. Autoclave testing under saturated steam conditions (400 kPa, ~180 °C, 24 h) demonstrated complete preservation of structural integrity in all RDBO-stabilized samples, with an average mass loss of 0.19 ± 0.01%, whereas colemanite-stabilized slags exhibited cracking and partial disintegration. The stabilization effect was achieved at a B₂O₃ content of 0.17–0.47 wt.% without boron contamination of ferrochrome. The proposed technology ensures long-term slag stability and enables the utilization of stabilized slag as a technogenic material for road construction.

The aim of this study was to investigate the effect of reduction roasting parameters on the phase transformations of the Ushkatyn-III ferruginous manganese ore and the efficiency of subsequent magnetic separation. The experimental procedure included preliminary high-intensity magnetic separation, reduction roasting at 650 °C for 3–5 h using 20–30 wt.% coal as the reducing agent, and low-intensity dry magnetic separation at magnetic field intensities of 0.1–0.6 T. Chemical composition was determined by standard analytical methods, while phase composition was analyzed by X-ray diffraction (XRD). Preliminary magnetic separation increased the manganese content in the magnetic pre-concentrate to 30.71–35.09 wt.%. The optimum results were obtained after roasting for 5 h with 30 wt.% coal, followed by magnetic separation at 0.2 T, producing a low-iron concentrate containing 33.26 wt.% Mn and 0.67 wt.% Fe, with a manganese recovery of 87.79% and an Mn/Fe ratio of 49.6. XRD analysis confirmed the partial reduction of hematite to magnetite (Fe₃O₄), providing the basis for efficient magnetic separation. The proposed process offers an effective approach for upgrading low-grade ferruginous manganese ores for manganese ferroalloy production.