The kinetics of sulphur transfer from gas to molten oxide systems.

The rates of sulphur transfer from gas to molten from oxides, silica and lime were studied on a laboratory scale. Experiments were carried out at a constant temperature of 1550°C, constant gas composition (CO, CO[2] corresponding to 10[-8] atm. oxygen partial pressure and also 2.8% SO[2] by volume) the only variable was slag composition. The extent and rates of oxidation of iron oxide melts were astermistsd in an identical apparatus containing the same atmosphere but without the sulphur gas. Melts were analysed for sulphur by the combustion and evolution methods. A new method, had been developed for the determination of ferric iron in slags. Modification of the method had been suggested for slags containing high sulphur and ferric iron. It was found that both the rate and degree of sulphurization depended on the state of oxidation of the slag and its silica content, the latter being a very important factor. The results of the work can be explained by assuming that bias diffusion of sulphur through the melt is the rate controlling factor and that sulphur can only replace oxygen which is not bonded to silicon. Work on FeO, FeO - SiO[2] melts showed that the ferrous-ferric reaction at the slag-gas interface was the rate determining step in sulphur transfer. The application of the results to steel-making practice had also been discussed