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研究了从两种不同希土矿物(氟碳铈矿和独居石)所得的混合希土氢氧化物中(含CeO_2～45%)用磷酸二丁酯(HDBP)萃取分离铈的条件.由于采用混合酸(硝酸加硫酸)溶解氢氧化物,可减少四价铈的还原,所以我们在此混合酸介质中研究了水相的酸度和希土浓度、有机相的磷酸二丁酯浓度、洗涤次数、洗液酸度、不同稀释剂(四氯化碳、氯仿、正丁醇、石油醚、苯、甲苯、二甲苯和混合稀释剂)等条件对萃取的影响.当水相的酸浓度为3.6N,R_2O_3为83.5克/升,用0.73—0.75MHDBP-CCl_4萃取时,一次萃取可获得纯度为90—95%的CeO_2,收率～91%,但分层较慢.如有机相以1:2的HNO_3溶液洗涤三次,纯度可提高至～99%,收率～90%.如使用混合稀释剂(CCl_4加n-C_4H_9OH,n-C_4H_9OH占有机相总体积的5—35%),对分层情况有所改善,一次萃取,不经洗涤,可获得纯度>97%的CeO_2,收率～90%.当改用0.73M HDBP-CHCl_3萃取时,一次萃取,不经洗涤,即可获得纯度～99%的Ceo_2,收率～91%,显著改善了分层情况,并可使用更高浓度的希土原料(R_2O_3可达120克/升).这样就为在较低酸度和有硫酸存在的介质中萃取分离铈,提供了一个有效的方法.
The conditions for the extraction and separation of cerium from mixed rare earth hydroxides (containing CeO 2 ~ 45%) and dibutyl phosphate (HDBP) from two different rare earth minerals (bastnaesite and monazite) Mixed acid (sulfuric acid and nitric acid) dissolves hydroxide to reduce the reduction of tetravalent cerium. Therefore, we studied the acidity and concentration of the aqueous phase, the concentration of dibutyl phosphate in the organic phase, the washing times, Lotion acidity, different diluents (carbon tetrachloride, chloroform, n-butanol, petroleum ether, benzene, toluene, xylene and mixed diluent) and other conditions on the extraction when the acidity of the aqueous phase was 3.6N, R_2O_3 is 83.5 g / L, when extracted with 0.73-0.75MHDBP-CCl_4, CeO_2 with 90-95% purity can be obtained in one extraction with a yield of 91%, but the delamination is slower.If the organic phase is extracted with 1: 2 HNO_3 solution was washed three times, the purity can be increased to ~ 99%, the yield ~ 90% .If the mixed diluent (CCl_4 plus n-C_4H_9OH, n-C_4H_9OH accounted for 5-35% of the total volume of the organic phase) Has been improved, an extraction, without washing, can be obtained with purity> 97% of CeO_2, yield ~ 90% .When the switch to 0.73M HDBP-CHCl_3 extraction, a Without washing, Ceo 2 with a purity of ~ 99% can be obtained with a yield of ~ 91%, which results in a significant improvement of the stratification and the use of higher concentrations of rare earth materials (R 2 O 3 up to 120 g / l) An effective method is provided for the extraction and separation of cerium in a medium of lower acidity and in the presence of sulfuric acid.