二水法湿法磷酸中常含有一定量硫酸根杂质,硫酸根的存在不仅降低了磷酸品质,而且增加了磷酸对硫酸的消耗。采用磷精矿为脱硫剂,研究了脱硫剂用量、反应时间、反应温度对湿法磷酸中硫酸根脱除的影响,并测算了二水硫酸钙在湿法磷酸中的溶度积。结果表明：固液质量比为5%的磷精矿粉可有效地脱除稀磷酸中的硫酸根,反应温度建议不超过70 ℃,反应2 h即可。此外,在稀磷酸中测算硫酸钙的溶度积为2×10^-2~3×10^-2。该研究对湿法磷酸生产过程中在降低硫酸根含量并提高湿法磷酸品质方面具有一定的指导意义。

Sulfate impurity,which exists in phosphoric acid by dihydrate process,not only reduces the quality of phosphoric acid,but also increases the consumption of sulfuric acid by phosphoric acid.The influence of desulfurizer dosage,reaction time and reaction temperature on the desulfurization was completed,using phosphorus concentrate as desulfurizer.Meanwhile,the solubility product of calcium sulfate dihydrate in wet-process phosphoric acid was measured.The results showed that sul-fate in phosphoric acid could be removed availably,when solid-liquid mass ratio of phosphorus concentrate was 5%.It was suggested that the reaction temperature should not exceed 70 ℃ and the reaction time should be 2 h.Moreover,the solubility product of calcium sulfate in phosphoric acid was in the range of 2×10^-2to 3×10^-2.This study has certain guiding significance in reducing sulfate content and improving the quality of WPA production.