Dephosphorization of High Manganese Molten Iron Treated with BaO-BaCl₂-Mn0 Flux and Oxidation by MnO₂

Abstract

Dephosphorization process of high manganese molten iron with BaO-BaCl₂-MnO flux by oxidation of MnO₂, includingslag recycle system, was investigated in a laboratory scale test.
By using BaO-BaCl₂ flux of 100kg/t and MnO₂ of 10-15kg/t, dephosphorization yield of 70% was achieved at 1400°C, if the molten iron with manganese content of 18 mass% has carbon content of 2 mass%. To get satisfactory dephosphorization, (BaO)/(BaCl₂) mass% ratio in the slag should be controlled to 50/50-70/30, MnO content in the slag to 20 mass%, and (BaO)/(SiO₂) mass% ratio should be larger than 15. Phosphate capacity of the slag was calculated to be 10^22.9-10^23.3.
Also, it is considered possible to use the slag repeatedly for dephosphorization by subsequent reduction of P₂O₅ in BaO-BaCl₂ slag with carbon at 1600°C.