Chemical Characterization and Smelting Performance of Silica–Carbon Composite Briquettes for Ferrosilicon Production

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.