溶剂萃取法脱除盐酸法湿法磷酸中铁的研究

Removal of Fe^(3+) from hydrochloric acid route phosphoric acid by sovent extraction

研究了以磷酸三丁酯(TBP)为萃取剂,二甲苯为稀释剂,从盐酸法湿法磷酸中萃取Fe^(3+)时,TBP、盐酸、磷酸、氯化钙和Fe^(3+)浓度对Fe^(3+)萃取效果的影响。研究结果表明,Fe^(3+)萃取率和分配系数随着磷酸三丁酯、盐酸和磷酸浓度的增加而增加。Fe^(3+)分配系数与TBP和盐酸浓度分别呈4和2.5次方关系。氯化钙浓度低时,Fe^(3+)萃取率非常低;氯化钙浓度较高时,Fe^(3+)萃取率才会显著增加。在TBP体积分数为12.5%时,Fe^(3+)萃取率和分配系数随着Fe^(3+)浓度增加而降低;以此为有机相,3级错流萃取,可以使稀磷酸溶液中的Fe^(3+)质量分数由0.128%降至0.008%。用TBP为萃取剂从盐酸法湿法磷酸中萃取Fe^(3+)时,可以用二甲苯作稀释剂。

The solvent extraction of Fe3＋ from the hydrochloric acid route phosphoric acid with t ri -n-butyl phosphate （TBP） as extracting agent and xylene as diluting agent was investigated.The effects of concentrations of TBP,hydrochloric acid, phosphoric acid,calcium chloride,and Fe3＋ on the extraction yield and distribution coefficient of Fe3＋ were studied.Results showed that the extraction yield and distribution coefficient of Fe3＋ increased with increasing the concentrations of TBP, hydro-chloric acid,and phosphoric acid.The distribution coefficient of Fe3＋ was 4 and 2.5-order with respect to the concentrations of TBP and hydrochloric acid,respectively.The extraction yield of Fe3＋ was low at low concentration of calcium chloride,while it significantly increased at high concentration ofcalcium chloride.The extraction yield and distribution coefficient of Fe3＋ dec-reased with increasing the concentrations of Fe3＋ when the volume concentration of TBP was 12.5%.The Fe3＋ mass fraction of hydrochloric acid route phosphoric acid decreased from 0.128% to 0.008% via a cross-current 3-stage extraction by 12.5% TBP.Xylene could serve as the diluent for extraction of Fe3＋ from the hydrochloric acid route phosphoric acid by TBP.