研究了杂质Mg2+、F-和酸不溶物对硝酸-磷酸水溶液中硫酸钙晶体形貌及晶粒大小的影响,对溶液中不同杂质含量下硫酸钙的晶体相貌和晶相进行了初步表征.结果表明,在所研究的杂质含量范围内,三种杂质对晶体形貌变化的影响不大,但粒子大小却有差异.XRD图谱说明,酸性介质中硫酸钙晶体没有以单一的晶相存在,而是半水和二水的混合体,且半水和二水各自所占的比例随杂质种类及含量的不同而不同,只是在镁离子含量较少时半水硫酸钙的XRD峰较强.硫酸钙结晶的过滤时间随酸性溶剂中Mg2+、F-和酸不溶物含量的增加而加长,硫酸钙在酸性介质中有一定的溶解度.%This paper investigated the effects of several impurities, including Mg2+ ,F- and acid-insoluble, on the crystal morphologies and particles of calcium sulfate in H3 PO4-HNO3 aqueous medium. The morphologies and crystalline phases of calcium sulfate under different impurities contents were characterized primarily. The results show that there were not obvious influences of three impurities on the crystal morphologies in the range of research, but differences in particle size. XRD analysis shows that calcium sulfate crystal existed as a mixture of hemihydrate and dihydrates in acid medium, rather than a single phase, and the change in proportion of hydrates with impurity type and content was various. Only at low magnesium contents, there were strong peaks of hemihydrates in XRD patterns. The filter time of calcium sulfate became longer with increasing impurity contents in acid solution, and there was a certain degree of solubility of calcium sulfate in acid medium.
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