Preparation of high-purity Strontium Carbonate from Celestite Concentrate by Double Decomposition-Roasting Process

摘要

The technology of using celestite concentrate to prepare high-purity strontium carbonate by double decomposition-roasting process was studied in this paper. The results showed that a maximal SrSO{sub}4 conversion of 97.77% was obtained when Na{sub}2CO{sub}3 was used under the conditions of liquid/solid ratio of 5/1, Na{sub}2CO{sub}3 concentration of 1.1mol/L, Na{sub}2CO{sub}3/SrSO{sub}4 molar ratio of 1.2, temperature of 75°C, and time of 75min. But the maximal conversion of SrSO{sub}4 was only 78.66% when (NH{sub}4){sub}2CO{sub}3 was used under the optimal conditions of liquid/solid ratio of 5/1, (NH{sub}4){sub}2CO{sub}3 concentration of 1.7mol/L, (NH{sub}4){sub}2CO{sub}3/SrSO{sub}4 molar ratio of 1.2, temperature of 60°C and time of 150min. The crude strontium carbonate obtained from double decomposition was roasted at 1200°C for 45min with anthracite, and the ratio of strontium carbonate and anthracite is 10/1, and the conversion was 72.30%. The high-purity strontium carbonate were obtained after the roasted products were leached, got rid of impurity and carbonated, in which the content of SrCO{sub}3 exceeded 98%, and CaCO{sub}3 was less than 0.5%, BaCO{sub}3 was less than 0.7%.