2013 Volume 53 Issue 7 Pages 1138-1142
Lab-scale experiment and industrial test for direct alloying with ferrosilicon-MoO3 self-reducing briquette have been conducted. In order to avoid volatilization of MoO3 during direct alloying, the high-temperature volatilization characteristics of MoO3 has been studied, and it can inhibit the volatilization of MoO3 when adding ~25% MgO during the heating. Furthermore, lab-scale direct alloying experiments with self-reducing briquette were carried out to determine the optimum composition of briquette to get high yield of Mo in a medium frequency induction furnace. The Mo yield was related to the excess reducing agent (ferrosilicon) and the right flux addition (MgO, CaF2) inside the briquette. The results indicated that the amount of ferrosilicon maintaining the mixing molar ratio Si/O at 2 should be added. The flux addition must be controlled to form molten slag rapidly inside the self-reducing briquette. With the optimum composition of reducing agent and flux addition, the yield of Mo could reach as high as ~96%. When adding the self-reducing briquette into a 60 t ladle of Shijiazhuang Iron and Steel Co. Ltd. for industrial test, the average yield of Mo was 98.25%, and the change in the technology did not have an impact on the quality of products.