使用分析纯试剂配料,在1350℃保温1 h的条件下合成了A/S=5(Al2O3与SiO2质量比)的铝酸钙熟料.研究了钙铝比C/A(除去与SiO2结合的CaO后CaO与Al2 O3的摩尔比)对熟料中12CaO·7Al2 O3晶体结构及其氧化铝浸出性能的影响,并通过X射线衍射和X射线荧光等分析手段对其作用机理进行了探讨.结果表明：由于12CaO·7Al2 O3量的增加,C/A=1.0~1.4时,石灰烧结法熟料溶出率随着C/A的提高而提高；在C/A=1.4时,熟料溶出率最高可达93.30%,此时CaO的缺失形成了有缺陷的12CaO·7Al2 O3,且其中CaO的物质的量小于11.3 mol；钙铝比提高到1.7时熟料溶出率又出现了下降趋势,这是由于CaO的饱和导致12CaO·7Al2 O3晶体择优生长取向发生变化,由(211)面开始向(420)晶面转变.
Calcium aluminate clinkers, in which the mass ratio of Al2O3 to SiO2(A/S) is 5, were prepared at 1500℃ for 1 h by proportioning pure reagents. The alumina leaching properties and crystal structure of 12CaO·7Al2 O3 in the clinkers with different molar ratios of CaO unbonded with SiO2 to Al2 O3 ( C/A) were studied. The effect mechanism of C/A on the clinkers was also discussed by X-ray diffraction and X-ray fluorescence analysis. When C/A is 1. 0 to 1. 4, the alumina-leaching ratio improves because the amount of 12CaO·7Al2O3 increases with increasing C/A. When C/A is 1. 4, the alumina-leaching ratio reaches the maximum value of 93. 30%. In this case, 12CaO·7Al2 O3 with defects forms, and the amount of substance of CaO is less than 11. 3 mol. With the further increase of C/A, the alumina-leaching ratio decreases, which is because the preferred orientation of 12CaO·7Al2 O3 changes from the (211) crystal plane into the (420) crystal plane.