铝酸钠粗液氧化铝浓度及溶出时间对硅钙渣物相组成的影响

Influence of alumina concentration and dissolution time in sodium aluminate solution on the phase composition of calcium silicate slag

以脱硅粉煤灰熟料为原料进行熟料溶出，通过XRD等检测手段，得出不同氧化铝溶出浓度、不同溶出时间下固相成分变化规律，探析了溶出过程二次反应历程。实验结果表明：从硅钙渣中物相组成判断，铝酸钠粗液氧化铝浓度控制在100～120g／L之间，溶出时间应在180min以内。在不同铝酸钠粗液氧化铝浓度条件下，随着溶出时间的延长，二次反应产物随着氧化铝浓度和溶出时间的变化而变化，硅钙渣主要物相为原硅酸钙、水化石榴石、钠硅渣和少量方解石。铝酸钠粗液中氧化铝浓度在80～115g／L之间时，二次反应开始时液相中的Na2CO3是引起原硅酸钙分解的主导因素；铝酸钠粗液中氧化铝浓度在115～125g／L之间时，二次反应开始时液相中的NaAl（OH）4和Na2CO3对原硅酸钙分解的影响程度基本相同；当铝酸钠粗液中氧化铝浓度在125～140g／L之间，二次反应开始时液相中的NaAl（OH）4是引起原硅酸钙分解的主导因素。

Desilication fly ash clinker was digested to obtain different concentration of alumina dissolution concentration. Secondary reaction during clinker digestion process was analyzed by XRD through analyzing changes of solid phase components in different dissolution time. The results show that the con- centration of sodium aluminate solution should be controlled at 100 ~ 120g/L and separation time of liquid and solid be controlled within 180min from the result of the phase composition of calcium silicate slag. Reaction products and reaction process change with prolongation of leaching time under different initial aluminate concentration. The main phases of calcium silicate slag are calcium silicate, hydrogarnet, sodium - silicon residue and a trace amount of calcite. When the concentration of sodium aluminate solution is between 80 ~ 115 g/L, Na2 CO3 is the dominant factor of the decomposition of calcium sili- cate at the beginning of the secondary reaction ; When the concentration of sodium aluminate solution is between 115 ~ 125g/L, NaAI（OH） 4 and Na2 CO3 are almost the same level influence factor of the decomposition of calcium silicate at the beginning of the secondary reaction ; When the concentration of so- dium aluminate solution is between 125 - 140g/L, NaA1 （OH） 4 is the dominant factor of the decomposition of calcium silicate at the beginning of the sec- ondary reaction.