Melting property of a slag for FeV alloy production by the electrical thermite method

Abstract

The effect of CaO content on the liquidus of a CaO-Al2O3-22% MgO-1% SiO2-2% FeO system and the influence of CaF2 and B2O3 contents on the liquid content of the slag at 1700℃ were calculated using Phase Diagram and Equilib module in thermodynamic software FactSage. The starting and ending melting temperatures of the slag obtained from production were measured by differential thermal analysis. When the CaO content in the slag is controlled at 25% approximately for FeV alloy production by the electrical thermite method, the melting property of the slag is good. The effect of CaF2 on the melting point depression of the slag is better than that of B2O3. Meanwhile, these two fluxes are not suitable to be used together when the mass ratio of Al2O3/MgO is high in the slag. Considering industrial application and environmental protection, the best addition of CaF2 in the slag is 2% to 5%.

Keywords

• ferroalloys
• electrical thermite method
• melting
• thermodynamic calculations
• optimal control