Effects of K2O Addition on the Reduction Smelting of Phosphorite for the Yellow Phosphorus Production

Yellow phosphorus produced by electric furnace is an important raw material for the production of high-purity phosphorus fine chemicals. High temperature of the slag system for the smelting of phosphorite resulted in the energy-extensive consumption. Moreover, the low activity of slag led to the low utilization efficiency. In the current study, the effects of K2O addition on the reduction smelting of phosphorite were investigated via thermodynamic calculations and experiment validation in order to reduce the smelting temperature and increase the activity of the slag. It has been found that K2O could reduce the melting temperature of SiO2–CaO–Al2O3 ternary system and accelerate the liquid-phase formation. Higher phosphorus volatilization ratio over 97% was obtained when the phosphorite smelted at 1500 °C with binary basicity of 0.8 and 3 wt.% K2O addition . Moreover, a K-bearing slag with high activity was obtained and it can be used as micronutrient fertilizer.