MANGANESE AND PHOSPHOROUS DISTRIBUTION EQUILIBRIUM BETWEEN CONVERTER SLAGS SATURATED WITH 2CAO·SIO_2 AND MGO AND LOW MANGANESE STEEL

摘要

In order to find out the proper thermodynamic conditions and predict manganese and phosphorous content during converter steelmaking for low manganese steel, the equilibrium experiments for manganese and phosphorus distribution between CaO-SiO_2-FetO-MgO_(sat.)-MnO-P_2O_5 converter slags saturated with 2CaO·SiO_2 and low manganese steel were carried out in a magnesia crucible at 1850～1923K under the pure argon atmosphere. The results indicated that manganese distribution ratios do not change obviously with the decrease of slag basicity, and their distribution ratios increased with increasing Fe_tO content in the slags. The phosphorus distribution ratios increased with the increase of slag basicity, and their distribution ratios increased with increasing Fe_tO content in the slags at first, then decreased with increasing Fe_tO content. The maximum manganese distribution ratio is 183.1 with the Fe_tO content of 32.5 mass% and the slag basicity of 4.2 at 1873K, and the corresponding contents of manganese, phosphorus and oxygen in steel are 0.011 mass%, 0.0012 mass% and 0.051 mass%, respectively, which is satisfied with the requirement of low manganese steel. The manganese and phosphorus distribution ratios decreased with increasing experiment temperature. There is a linear relationship between the equilibrium manganese and phosphorous distribution ratios and temperature in the present work.