Demanganisation of high manganese pig iron to produce high manganese stag

Pig iron with a high manganese content makes further processing to steel using converter technology difficult and unprofitable. In the present study, external demanganisation of high manganese pig iron before the oxygen converter process has been investigated. Pilot plant experimental heats were designed and carried out to optimise the demanganisation process, to produce hot metal adequate for the conventional LD converter, and high manganese slag suitable for the production of silicomanganese. Various high manganese pig irons with different [Si]/[Mn] contents were treated by injection of various oxidisers at varying temperatures, slag basicities and injection rates. The optimum conditions for the demanganisation process have been attained by injection of an oxygen gas-manganese ore mixture at the injection rate of 6.8 L min(-1) kg(-1) into molten high manganese pig iron with a [Si]/[Mn] ratio of 0.3 at an initial temperature of 1350degreesC and slag basicity of 0.3-0.4.