Cextrant 230从低品位铜矿H_(2)SO_(4)-NaCl浸出液中选择性提取回收铜

助浸剂NaCl可提高硫酸在常温常压下浸取低品位复杂铜矿时铜的浸出率,但也形成了含铜的混酸溶液。二(2-乙基己基)-(N-(2-乙基己基)氨基)甲基膦酸酯(Cextrant230)对混酸(H_(2)SO_(4)+HCl)溶液中Cu^(2+)、Fe^(3+)、Co^(2+)、Mg^(2+)和Al^(3+)的萃取行为进行了研究。结果表明,Cextrant 230对混酸溶液中的Cu^(2+)和Fe^(3+)具有良好的萃取能力和选择性,而对Co^(2+)、Mg^(2+)和Al^(3+)的萃取能力较弱;Cl-可促进Cu^(2+)的萃取,而SO_(4)^(2-)和HSO_(4)^(-)对Cu^(2+)的萃取起抑制作用;Cu^(2+)的萃取过程是放热反应;当水相初始pH值为1.16,ρ(Cl-)为20g/L时,c(Cextrant230)=0.60mol/L对Cu^(2+)的饱和负载容量为13.1g/L;负载有机相中的Cu^(2+)可用H_(2)SO_(4)完全反萃;经2级逆流萃取优先除Fe^(3+),混酸模拟液中的ρ(Fe^(3+))从0.65g/L减少至32mg/L,Cu^(2+)的共萃取率仅1.5%;再经4级萃取,1级洗涤,3级反萃,可获得纯度大于99.7%的Cu2(OH)2CO3产品,铜收率为98.5%。

Synergistic extraction and separation of thorium from rare earths in chloride media using mixture of Cextrant 230 and Cyanex 923

In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex 923 was investigated.The maximum synergistic enhancement coefficient(R)of 1.53 is obtained at 1:1 molar ratio of Cextrant 230/Cyanex 923.The syne rgistic extracted species of Th^(4+)is determined as ThCl_(4)·2Cextrant 230·Cyanex 923.The synergistic extraction of Th^(4+)is an entropy-driven exothermic process.The loading capacity of 0.60 mol/L mixed extractant for thorium is about 17.10 g/L(calculated as ThO_(2)),and the loaded thorium in the organic phase can be effectively stripped by distilled water.For comparison,rare earth cations are barely extracted under the similar conditions,suggesting that the mixtures can be applied to separate thorium from rare earths.A cascade extraction process was developed based on the synergistic extraction system to separate thorium from the hydrochloric acid leaching of bastnaesite.The content of thorium in the leaching solution decreases obviously from 19.90 mg/L to1.4μg/L by 3 stages of extraction,which is superior to sole Cextrant 230 or Cyanex 923.The introduction of Cextrant 230 into the extraction system not only lowers the usage of Cyanex 923 but also enhances the selective extraction of thorium at low acidity,implying that the synergistic extraction system can selectively extract thorium more efficiently and economically than the sole systems.

Cextrant 230对氟碳铈矿盐酸优浸液中钍和铁的选择性去除

研究了(二(2-乙基己基)-(N-(2-乙基己基)胺基)甲基膦酸酯(Cextrant 230,记为L)萃取剂对氟碳铈矿盐酸优浸液中Th(Ⅳ),Fe(Ⅲ)和稀土(Ⅲ)的萃取行为。结果表明:Cextrant 230对HCl介质中的Th(Ⅳ)和Fe(Ⅲ)有良好的萃取性能,而对稀土(Ⅲ)不萃取;Cextrant 230与Th(Ⅳ),Fe(Ⅲ)的萃合物结构式分别为ThCl4·4L和HFeCl4·L;萃取过程的热力学参数结果表明,Fe(Ⅲ)的萃取反应是吸热过程,而Th(Ⅳ)的萃取不受温度影响;当水相酸度为0.28 mol·L^(-1)HCl时,0.4 mol·L^(-1)Cextrant 230萃取Th(Ⅳ)和Fe(Ⅲ)的饱和负载容量分别为0.013和0.12mol·L^(-1);负载有机相中的Th(Ⅳ)和Fe(Ⅲ)可采用水和1.0 mol·L^(-1)HNO3分步反萃;经3级错流萃取,氟碳铈矿盐酸优浸液中的Th(Ⅳ)和Fe(Ⅲ)含量明显降低,其中,Th(Ⅳ)从65 mg·L^(-1)降至0.03 mg·L^(-1),Fe(Ⅲ)从5069 mg·L^(-1)降至42.56 mg·L^(-1)。