Extraction And Separation Of Rare Earth And Copper By Cextrant 230

In this work,the extraction and separation of trivalent rare earths from nitric acid medium was studied by using di（2-ethylhexyl）[N-（2-ethylhexyl）amino methyl]phosphonate（Cextrant 230,abbreviated as B）and the mixture of Cextrant 230 and acid extractants.Cextrant 230 was also applied to the extraction and separation of copper from mixed sulfuric acid and hydrochloric acid medium.The main results are as follows:（1）The introducing of LiNO₃improved the performance of Cextrant 230 for rare earths extraction.The extraction sequence followed Lu>Yb>Tm>Er>Ho>Dy>Y>Tb>Eu>Sm>Gd>Nd>Pr>Ce>La.The extracted complex was determined as RE（NO₃）₃·3B.The loading capacity of 30%（v/v）Cextrant 230 for Lu³⁺was measured to be 34.38 g/L,85%of which can be stripped by H₂SO₄ solution with 3.0mol/L H⁺.（2）The mixture of Cextrant 230 and Cyanex 272（HA）showed a positive synergistic effect on the extraction of rare earths,the maximum synergistic enhancement coefficient of Er³⁺reached 3.25 at X_{cextrant 230} of 0.8.The extracted complex of Er³⁺was determined as Er（NO₃）₂A·3B.The extraction process of Er³⁺was a spontaneous endothermic reaction.The loading capacity of 30%（v/v）mixture(X_cextrant230=0.8)for Er³⁺was measured to be 6.67 g/L,95%of which can be stripped by H₂SO₄solution with 0.02 mol/L H⁺.（3）Cextrant 230 exhibited favorable selective performance for copper extraction from mixed sulfuric and hydrochloric acid solution.The extraction of Cu²⁺was facilitated by Cl^-but restrained by HSO₄^-and SO₄^2-.The extraction process of copper was an exothermic reaction.The loading capacity of 30%（v/v）Cextrant 230 for Cu²⁺was measured to be 13.1 g/L,which can be complete stripped by 0.5 mol/L H₂SO₄.An extraction process for the selective extraction and recovery of Cu（II）from a raffinate obtained after the removal of iron by using 0.8 mol/L Cextrant 230 was proposed.The copper product with the purity of 99.7%and yield of 98.5%was obtained by using 0.2mol/L Cextrant 230 after 4 stages of extraction,1 stage of scrubbing and 3 stages of stripping.