Development of synthetic slag for desulphurisation of the steel during steelmaking in induction furnace

Abstract

Currently, steel production through induction furnace is nearly 30% of total steel production in the world. However, steel produced through induction furnace routes contains high sulphur (0.06 to 0.1 wt %) which is not acceptable for the structural steels. Therefore, it is imperative to develop the synthetic slag for desulphurisation of the steel in the induction furnace. The slag properties such as sulphide capacity, sulphur partition ratio, viscosity, liquidus temperature, the solubility of components, basicity are considered to design synthetic slag for desulphurisation of the steel in the induction furnace. Developed synthetic slag is consist of 20-30 wt% SiO2, 5-20 wt% Al2O3, 40-60 wt% CaO, 5-10 wt% MgO. The evaluation of synthetic slag is performed in the induction furnace for desulphurisation of plain carbon and alloy steel. The maximum degree of desulphurisation is 84 % with the addition of 2-3 wt % synthetic slag in the induction furnace for Al killed steel while 32 % for non –killed steel is achieved. The desulphurisation time to achieve the sulphur level (0.03-0.04) is 10 minutes in the induction furnace using developed synthetic slag (2-3 wt % liquid metal). Sulphur partition (Ls, e) and sulphide capacity of synthetic slag increase with basicity of the developed synthetic slag.