CALCIUM CARBIDE POWDER INJECTION INTO HOT METAL .2. SIMULTANEOUS DESULFURIZATION AND DEOXIDATION

Calcium carbide was injected into an induction furnace containing 70 k g of carbon saturated iron. In the second part of the two part paper s imultaneous desulphurisation and deoxidation were studied by continuou sly measuring the oxygen activity and frequently sampling for sulphur content. At the start of injection there was a period of slow desulphu risation, corresponding to a period of deoxidation. After that, it was found that the apparent first order rate constant for desulphurisatio n increased as the oxygen activity was decreased. A mathematical model was developed to describe diffusion controlled desulphurisation and d eoxidation at calcium carbide and lime particles. (Lime is always pres ent in commercial calcium carbide.) The model accurately describes the trajectories of sulphur and oxygen during refining. The rates of desu lphurisation and deoxidation were consistent with 30-50% of the partic les contacting the melt. A similar conclusion was reached in Part 1 (t his issue) via a heat transfer analysis. Finally, the industrial impli cations of these findings are discussed.