Abstract:
The conversion of celestite (SrSO4) to strontium sulphide (SrS) by the carbothermic reduction process was investigated as a route for the production of SrCO3 from high-grade Turkish celestite ores. Experiments were conducted in the temperature range 900-1400°C and metallurgical-grade coke was used as the reducing agent. The effects of reduction temperature, amount of carbon and roasting time were studied. The products of reaction (black ash) were examined, mainly with the use of X-ray diffraction and flame atomic absorption spectrometry. The results include data on recoverable Sr obtained as strontium carbonate precipitate. The conversion reaction is complete at 1300°C, and it begins at lower temperatures. In addition to sulphate-sulphide conversion, all alkali earth metals found in the ore can be transformed to carbides in the process of reduction, especially when the roasting time and amount of carbon added to concentrate are increased. The reduction reaction seems to be very fast and it is concluded that the manufacture of SrCO3 is feasible from the roasted product. © The Institution of Mining and Metallurgy 1998.