原硅酸钙在铝酸钠溶液中的反应行为

Reactive behaviors of calcium silicate in aluminate solutions

以CaO和SiO2为原料合成2CaO·SiO2,通过测定SiO2浓度分析原硅酸钙反应活性的变化规律;基于质量守恒,计算渣中钠硅渣和钙硅渣分配比例。实验结果表明,在铝酸钠溶液体系中,反应时间的延长、氧化铝浓度的升高均有利于原硅酸钙的分解和溶出液中二氧化硅浓度的升高,溶出液中二氧化硅浓度最高增幅可分别达到9.97倍和11倍;同时,温度升高会显著促进原硅酸钙的分解与钙硅渣的生成,在136℃反应1h后二氧化硅总反应率可达43.06%;在铝酸钠溶液中加入碳酸钠,可能因"协同效应"而促进原硅酸钙的分解;铝酸钠溶液苛性比变化对原硅酸钙的分解影响不明显。随着纯铝酸钠、碳酸钠和氢氧化钠溶液浓度的升高,原硅酸钙的Zeta电位绝对值增大,其原因可能是溶剂化层相应的Al(OH)4-,CO32-和OH-含量增多,有利于原硅酸钙的分解。

Reactive behaviors of 2CaO·SiO2 synthesized from CaO and SiO2 was studied in term of concentration of silica, and the proportion of sodium aluminosilieate hydrate and hydrogarnet was also calculated on the basis of conservation of mass. The results show that the prolongation of time or the increase of Al2O3 concentration favors the decomposition of 2CaO·SiO2 and leads to more silica left in aluminate solution. The maximal SiO2 concentration in solution increases by 9.97 and 11 times compared with the minimum SiO2 concentration respectively. The increase of the temperature fairly benefits the decomposition of 2CaO·SiO2 and formation of more hydrogamet. The total reaction rate of silica reaches 43.06% at 136℃ after reaction for 1 h. When Na2CO3 is added into NaAl（OH）4 solution, more 2CaO·SiO2 is decomposed owing to synergism, aK affects slightly the decomposition of 2CaO·SiO2. The absolute value of Zeta potential of 2CaO·SiO2 rises with the increase of pure NaOH, NaAI（OH）4 and Na2CO3 concentration, which means more OH^-, AI（OH）4^- and CO3^2- stays in the solvent layer of 2CaO·SiO2 and favors the decomposition of 2CaO·SiO2.