溶剂萃取法是一种经济有效的湿法磷酸净化方法。在转盘塔中,以甲基异丁基酮（MIBK）为萃取剂,开展了净化湿法磷酸的实验研究。考察了搅拌转速、相比对磷酸萃取率、杂质离子选择性、洗涤效果和反萃效果的影响。研究结果表明：萃取过程适宜的相比（溶剂与磷酸的体积比）为4,搅拌转速为200~400 r/min,在此条件下磷酸萃取率为85%;洗涤过程的搅拌转速不应大于100 r/min,适宜的洗涤酸用量为溶剂相体积的10%~15%,在此条件下铁离子（Ⅲ）和镁离子脱除率均在90%以上、铝离子脱除率大于70%、硫酸根脱除率为50%~60%;反萃过程搅拌转速不应大于200 r/min,适宜的反萃水用量为溶剂相体积的9%~15%。MIBK对阳离子的脱除效果较好,但是对阴离子的脱除效果不佳。经过萃取、洗涤和反萃3个过程,磷酸收率为57.8%~70.3%,磷酸中铁离子（Ⅲ）含量可以达到工业级磷酸标准,但是硫酸根的含量无法达标,需要结合其他方法进一步脱除。

Solvent extraction is an economical and effective method for the purification of wet process phosphoric acid（WPA）. WPA extraction proces was carried out using methyl isobutyl ketone（MIBK） as an extractant in a rotating disc column （RDC）.The effect of rotation speed and phase ratio on the extraction rate,the selectivity coefficient of impurities,and phos-phoric acid washing and stripping was studied.The results showed that the optimum extraction ratio（volume ratio of solvent to phosphoric acid） was 4,the stirring speed was 200~400 r/min,and the extraction rate of phosphoric acid was 85%.The stir-ring speed in the washing process was limited to 100 r/min.The appropriate amount of washing acid was 10%~15% of the vol-ume of solvent phase.The removal rates of Fe³⁺ and Mg²⁺ were more than 90%.The removal rate of Al³⁺ was more than 70% and the removal rate of SO₄^2- was 50%~60%.The stirring speed of stripping process was limited to 200 r/min,and the appropriate amount of stripping water was 9%~15% of the volume of solvent phase.MIBK had good removal effect on cations,but poor re-moval effect on anions.After purification by extraction,washing and stripping,the yield of phosphoric acid was 57.8%~70.3%. The content of Fe³⁺ in phosphoric acid could meet the standard of industrial phosphoric acid,but the content of sulfate could not meet the standard,so it needs to be further removed in combination with other methods.