Technology for the production of high-carbon ferrochromium using mono-briquettes

Abstract

The article presents results of large-scale laboratory studies on the basis of Chemical-Metallurgical Institute named after Zh. Abishev on establishing the possibility of using a mono-charge for smelting standard carbon ferrochromium. Enlarged-laboratory studies were carried out in an ore-thermal furnace with transformer capacity of 200 kVA. Duration of the pilot campaign was 4 days. Three variants of briquettes containing various reducing agents were tested, including: traditional charge (coke PRC + special coke + Borolinsky coal); briquettes with coal from Shubarkol; briquettes with Borlinsky coal; briquettes with coke of China. As a comparative variant, traditional technology with charge materials without briquetting was used. In total, when conducted large-scale laboratory studies it was 41 smeltings. The tests began with a comparative version, which was chosen as technology closest to the technology at Aktobe ferroalloy plant. On the traditional charge, top worked without the uniformly gassing over entire surface of the top. Recovery rate of chromium in the alloy was 79.3 %. Change to briquettes with Shubarkol coal in general has led to the process intensification with more stable current load. The furnace productivity increased to 165.9 kg Cr/day due to increase in the contact surface of reacting phases in briquettes. When using briquettes with Borlinsky coal, satisfactory technological parameters of the smelting process for high-carbon ferrochrome were also obtained, extraction rate of chromium into the metal was 84.91 %. When using briquettes from 0 – 10 mm ore fraction ore and CPR coke in the charge, furnace operation and state of the top were not different from previous periods. The charge also went off evenly, without collapses, the briquettes on the top were not destroyed and current load was highly stable. The work also presents comparative technical and economic indicators for all technologies using mono-charge briquettes.