快烧对磷石膏可溶磷杂质及其脱水产物的影响

摘要

磷石膏中含有少量可溶磷等杂质，作为石膏胶凝材料直接使用存在不利影响。利用快烧处理3种不同磷杂质含量的磷石膏，通过控制快烧温度和时间，研究了快烧后磷石膏总磷、可溶磷和pH值变化情况，并采用XRD对快烧后磷石膏物相进行分析。结果表明，快烧能明显降低磷石膏可溶磷杂质含量，快烧时间延长和温度提高都有利于可溶磷含量降低；快烧对总磷含量没有影响；快烧处理后磷石膏中有半水石膏生成，磷石膏pH值也明显增加。%The soluble phosphate impurities in phosphogypsum impede its utilization in directly producing binding material. Three phosphogypsums with different content of phosphate impurities were treated by fast ifring for different time and temperature. After fast ifring, the total phosphate content, soluble phosphate content and pH value of phosphogypsum were measured and mineral phases were analyzed using XRD. It is shown that the soluble phosphate content decreased considerably after fast ifring with increasing of the treating time and temperature. The fast ifring would not change the total phosphate content in phosphogypsum whatever ifring conditions were used. The hemihydrate gypsum appeared and the pH value increased after fast ifring.