Pretreatment of hot metal with soda ash and with soda ash sodium-sulfate mixture

Experiments were carried out on the pretreatment of Indian hot metal in 10 and 100 kg air induction furnaces with a view to removing silicon, sulphur, and phosphorus simultaneously using soda ash and a mixture of soda ash and sodium sulphate. The procedure adopted was to pour the molten iron in a thin stream into the liquid reagent (reagent rate = 5-7.5%) kept in a ladle. The results indicate higher desiliconisation and greater consistency with soda ash-sodium sulphate mixture than with soda ash alone and higher desulphurisation with soda ash than with the mixture. No definite conclusion could be drawn regarding the efficacy of the mixture versus soda ash for dephosphorisation. The present results on desulphurisation with soda ash agree well with those obtained by electroslag remelting of pig iron using basic oxygen furnace slag containing lime and spar.