Study on Removal Rule of Impurity Elements in Preparation of Ferromolybdenum from Calcium Molybdate

Calcium molybdate is a waste produced by the molybdenum industry, and it is very feasible to replace part of molybdenum oxide with calcium molybdate for smelting by the carbon reduction method. In this paper, through the one-factor test, we obtained the optimal conditions for the removal of impurity elements P, S, C, and Si as follows: melting temperature of 1525°C, holding time of 25 min, and alkalinity of 1.3. The contents of impurity elements P, S, C, and Si in ferromolybdenum alloy were detected as 0.046%, 0.041%, 1.43%, and 1.09%, respectively, under these conditions, and the removal rates of P and S could be up to 79.36% and 65.21%. Under this condition, three phases of Mo2C, Fe3Mo, and Fe3Mo3C exist in ferromolybdenum alloy, in which the distribution of the P, S, and C elements decrease in order. The slag system is mainly composed of a CaO-SiO2 binary system, and, under the above research conditions, P, S, C, and Si are made to enter into the slag system in different forms to achieve the decontamination effect of ferromolybdenum. The research results are of great significance for the expanded utilization of calcium molybdate and the improvement of ferromolybdenum quality.