Abstract
This work presents the results of theoretical and experimental studies on the use of silicon production waste in the form of microsilica as a raw material for the production of metallurgical grade silicon. It is known from practice that the granulometric composition of microsilica does not allow its use in metallurgical processing. The authors of this work propose its use together with a carbonaceous reducer as part of a briquetted monocharge. In this work, the optimal composition of the charge mixture for briquetting is determined. The main focus is on assessing the strength characteristics of the briquettes and analyzing their efficiency in the silicon smelting process. The strength of the briquettes was studied by compression and drop methods. As a result, in terms of strength and other characteristics, it is highly advisable to use briquettes consisting of microsilica and special coke at a ratio of 65/35%. The obtained batches of high-strength briquettes were tested for the smelting of metallurgical grade silicon in a large-scale laboratory ore-thermal furnace with the aim of replacing the traditional charge mixture (high-quality quartzites, petroleum coke, wood chips, etc.) with monobriquettes. It was established that the briquetted monocharge ensures more intensive reduction processes and improves melting conditions compared to the traditional charge. This leads to higher silicon recovery rates, which was confirmed by tests, during which the maximum recovery rate reached 82.76% with a 30% replacement of the charge with briquettes. Batch of metallurgical silicon with a Si content of 95–96% was obtained.