Study on the separation and removal of sulfuric acid from waste aluminum polishing solution by solvent extraction and its mechanism
The present work investigated a solvent extraction system of removing sulfuric acid and purif-ying phosphoric acid from waste aluminum polishing solution.The effects of trialkylamine(N235)concen-tration,extraction temperature,phase ratio and oscillation time on the extraction rate were systematically studied.The McCabe-Thiele diagram method predicts that more than 98％H2SO4 could be removed after three theoretical stages at a phase ratio of O/A=2.A three-stage counterflow extraction was carried out through a series of batch countercurrent experiments,indicating that 95.40％H2SO4 can be extracted,with co-extraction of only 3.33％H3PO4.The results show that the system has high selectivity for H2SO4 and achieves efficient separation of H3PO4 and H2SO4.According to the mechanism study,the composi-tions of the extraction complex was determined to be H2SO4·2[N235],and the N235 extraction of H2SO4 occurred by the ion pair association mechanism.
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维普
