Purification of WPA by solvent extraction method with methyl isobutyl ketone(MIBK)as extractant is carried out in a reciprocating plate column.The effect of vibration frequency and phase ratio on the extraction rate,the selectivity coefficient of impurities,washing effect and stripping effect is studied.The results show that,the optimum extraction ratio is 4.1,vibration frequency is 300 r/min,and the extraction rate of phosphoric acid is 84%;The optimized vibration frequency in washing process is 150 r/min,and the appropriate amount of washing acid is 14.2%,under these conditions,the removal rates of Mg2+,Fe3+,Al3+,SO42-are 91%,87%,80%,52%,respectively;For reverse extraction process,the optimized vibration frequency is 200 r/min,the appropriate amount of water is 13.8%,and the reverse extraction rate is 92%,w(H3PO4)of reverse extraction phosphoric acid is 52%.MIBK has good removal effect on cations,but poor removal effect on anions.The content of Fe3+ and SO42-in phosphoric acid purified by extration can not meet the standard of industrial phosphoric acid,it needs to be further removed in combination with other methods.
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