硫铝酸钙的氧化铝溶出性能

Alumina leaching properties of calcium sulphoaluminate

使用分析纯CaCO_3、Al_2O_3与CaSO_4·2H_2O配料,在1375℃、保温2 h的条件下合成了纯物相硫铝酸钙3CaO·3Al_2O_3·CaSO_4(C_4A_3S),对其物相组成和微观形貌进行了表征。并探究了碳碱浓度、苛碱浓度、溶出温度、溶出时间、粒度等因素对C_4A_3S氧化铝溶出性能的影响。结果表明:C_4A_3S的氧化铝溶出性能随着碳碱与苛碱浓度的增加先提高,之后趋于稳定。粒度越小,溶出率越高。与七铝酸十二钙12CaO·7Al_2O_3(C_(12)A_7)相比,C_4A_3S的孔洞状结构使其氧化铝更易溶出,在10 min时氧化铝溶出率即达到98%以上,且溶出所需的碳碱浓度与溶出温度均低于C_(12)A_7。在最佳条件:碳碱80 g·L^(-1)、苛碱10 g·L^(-1)、溶出温度80℃、溶出时间10 min下,C_4A_3S的氧化铝溶出率为98.76%。

Analytically pure carbonate calcium, alumina and dihydrate calcium sulfate were used to synthesize calcium sulphoaluminate（3CaO·3Al2O3·CaSO4, C4A3S） at 1375℃ for 2 h. The phase compositions and microstructure were characterized. The effects of carbon alkali concentration, alkali concentration, leaching temperature, leaching time and particle sizes on the alumina leaching properties of C4A3S were explored. The results show that the alumina leaching ratio of C4A3S increases with the increase of concentration of sodium carbonate and alkali, then trends to stable. The leaching ratio becomes higher when the particle size of clinker decreases. Compared with 12 CaO·7Al2O3（C（12）A7）, the alumina of C4A3S is easier to be dissolved because of its porous structure, and the alumina leaching ratio is up to 98% under 10 min leaching. The concentration of sodium carbonate and the dissolution temperature of C4A3S is lower than that of C（12）A7. The alumina leaching ratio of C4A3S could reach 98.76% under the optimum conditions： sodium carbonate 80 g·L-1, alkali 10 g·L-1, dissolution temperature 80℃ and dissolution time 10 min.