清净剂原料石灰在空气中的晶相变化

THE CRYSTALLINE CHANGES OF RAW QUICKLIME FOR DETERGENT IN ATMOSPHERE

用X射线衍射仪(XRD)和扫描式电子显微镜(SEM)考察不同来源的生石灰样品在空气中的晶相和显微形貌等变化。结果表明,CaO首先吸H_2O变成小晶粒Ca(OH)_2,然后再吸收CO_2变成球霰石和方解石两种晶型CaCO_3;形成CaCO_3初期释放出的H_2O可能加速方解石型Ca-CO_3形成;CaO及其相变产物的显微粒子形貌大致分为三类。还比较了各样品的晶相变化速率和晶粒大小变化。

The changes of crystalline structures and microscopic features for various quicklimes in atomsphere have been studied by means of XRD and SEM techniques. CaO at first absorbs H_2O from the air and transforms into smaller Ca (OH)_2 grains,then absorbs CO_2 to become either vaterite type of CaCO_3 or calcite type of CaCO_3·H_2O released from the samples during the initial stage of formation of CaCO_3, may accelerate the formation of calcite type of CaCo_3. The SEM features of CaO and products resulted from CaO can be classified into three types according to the stickability between grains. The transformation rates of crystalline and the changes of the size of crystallites for different samples are also investigated.