酸化性雰囲気下における溶融スラグの気化脱硫

Abstract

The rates of desulphurization from liquid slag to the gas phase have been studied under an oxidizing atmosphere. A series of experiments was carried out by introducing Ar-O2 gas mixtures on to the surfaces of those liquid slags containing sulphur, such as CaO-SiO2, CaO-Al2O3 and some CaO-SiO2-MO ternary slags as well as CaF2 bearing slags.The results are as follows:(1) The desulphurization reaction of those slags by oxidizing gases is divided into a rapid rate reaction at the initial stage and a slow rate reaction at the later stage. The former should be controlled by the chemical reaction at the surface of the slags and the latter by the diffusion of sulphur in slags.(2) The rates of desulphurization of slag are proportional to the square root of partial pressure of oxygen and the rates of desuliphurization of the binary CaO-Al2O3 are higher than those of the CaO-SiO2 system. However, the rates of desulphurization for ESR slags are higher than those for CaO-Al2O3 slag. The rate constants for CaO-SiO2-MO ternary slags can be estimated from the sulphide capacity of the slags.(3) It was found that the rates of desulphurization increase in proportion to the concentration of basic oxides (CaO, MgO, MnO, FeO) but decrease as acid oxides (SiO2, Al2O3) contents are increased. Particularly, the effects of MnO and FeO are significant.