磷石膏制备氟化钙工艺研究

Study on preparation of calcium fluoride form phosphogypsum

利用磷肥厂副产的磷石膏为原料，将大块物细碎后经不同溶剂洗涤再干燥磨粉，与一定量的活性炭混合均匀后在800-900℃的高温马弗炉中煅烧60min，所得粉末经检测含CaO高达90％以上。接着以煅烧磷石膏所得的CaO和分析纯的NH4F为原料反应制备CaF2，实验过程中主要考察了溶液pH值、反应时间、原料的物料比、反应搅拌速度和干燥时间对产品质量的影响。实验结果表明：当反应溶液pH值为1、物料比为1：1、反应时间为60min、干燥时间为80min、搅拌速度为300r·min^-1时，CaF2的质量最佳，其纯度可高达91．84％。

Phosphogypsum obtained from phosphate fertilizer plant as raw material, which was crused, washed by different solvents, dried and milled to powder. Then the powder was mixed and calcined 60 minutes with a certain amount of activated carbon in muffle furnace at 800 - 900℃. Calcium oxide can be obtained by the previous method, and its purity is up to 90%. Calcium oxide obtained by calcining phosphogypsum and the analytically pure ammonium fluoride were used to synthetic calcium fluoride. Many factors, such as the acidity of solution, reaction time, material mole ratio, stirring speed and drying time, were studied during the experiment. The results indicate that the optimum operating conditions are the pH of solution is 1, reaction time is 60 minutes, material mole ratio is 1：1, stin-ing speed is 300r ·min^-1 and drying time is 80 minutes. The purity of calcium fluoride product is 91.84%.