The Application of Equilibrium Calculation to the Converting Reaction of Copper Matte in a PS Converter.

Abstract

Changes of the matte grade and oxygen pressure during the slag making stage in a PS copper converter were calculated by equilibrium calculations. In the calculation a slag making stage was simulated by many calculation steps in series, each of the steps being assumed in an equilibrium state. Results of the calculation were compared with experimental values measured in pilot and commercial converters.1. Calculated and measured matte grade changes were in good agreement with each other during the slag making stage. In particular, both of the changes showed that in the beginning of the stage there was a period of time for which the matte grade did not increase appreciably in spite of blowing. According to the present calculation, this was attributed to an increase of oxygen disolved in the matte.2. Calculated oxygen pressures at the beginning and the end of the stage agreed relatively well with those measured for the matte before blowing and for the converter slag after the stage, respectively. However oxygen pressures measured through the converter mouth during the stage were rather higher than those predicted by the calculation. Some of the measurements gave higher oxygen pressures than those measured even at the end of the stage.3. To explain the above mentioned phenomena by equilibrium calculation, a two-zone converter model has been developed. In the model the matte holding zone in a converter consists of two zones, i. e. a magnetite formation zone and a magnetite reduction zone, which are assumed in a different equilibrium state. By setting a proper ratio of the two zones, differences in oxygen pressure between the white metal and the converter slag at the end of the slag making stage were explained to some extent.