| In today's high technology and new materials and new energy development,the development and utilization of rare earth resources is of vital importance.However,in the leaching process,hetero ions on the surface of rare earth minerals will also be leached,especially aluminum ions due to their similar nature to rare earth ions,which will form a competitive extraction in the extraction and separation process of rare earths,reducing the extraction capacity of rare earths,and easily lead to emulsification in the extraction process.In this paper,we studied the process of aluminum removal by complexation of rare earth materials and liquids,and proposed the process of aluminum removal by PBTCA and the process of aluminum removal by selective complexation-turbidity point extraction of glutamic acid and histidine,respectively.1?PBTCA was used as the aluminum ion precipitant to investigate the effects of solution p H,PBTCA dosage,reaction temperature and reaction time on the separation effect of rare earths and aluminum ions,and the results showed that:MPBTCA:MAl=1:5,p H=4.5,reaction temperature 30?,reaction time 10 min,the removal rate of aluminum ions could reach 98.39%,and the rare earth The loss rate was only 5.39%.2?Glutamic acid was used as a complexing agent to selectively complex aluminum ions,and then a nonionic surfactant was added to extract and separate aluminum ions from the rare earth feed solution using turbidity point extraction.The effects of solution p H,reaction temperature,equilibrium time,amount of glutamic acid,reaction time and amount of Triton X-114 on the removal of aluminum were investigated.The results showed that Mglu:MAl=3:1,adjusting the p H of the solution to 4.5,maintaining a constant temperature of 40°C,and adding 10 m L of Triton X-114 nonionic surfactant after 10 min of reaction,the primary removal rate of aluminum ions could reach 78.01%and the loss rate of rare earths was only 5.09%at an equilibration time of 10 min.The reaction equation of glutamic acid with aluminum ions was determined,and the lowest extraction concentration of aluminum ions in the glutamic acid complexation extraction solution,CAl=0.0447±0.003g/L,and?(Al/RE)=66.15,was studied by multiple extractions,indicating that the aluminum ions in the mixed solution could be effectively separated from the rare earth ions when using glutamic acid as a complexing agent in combination with the cloud point extraction method.3?Histidine was used as a complexing agent to selectively complex aluminum ions,and then non-ionic surfactants were added to extract and separate aluminum ions from rare earths by turbidity point extraction.The effects of solution p H,reaction temperature,equilibrium time,amount of histidine,reaction time and the amount of Triton X-114 on the effect of aluminum removal were investigated.The results showed that:Mhis:MAl=3:1,adjusting the p H of the solution to 4.5,constant temperature of 40°C and adding 10 m L of Triton X-114 nonionic surfactant after 10 min of reaction,the primary removal of aluminum ions could reach 70.85%at an equilibrium time of 10 min,and the loss of rare earths was only 4.45%.The reaction equation of histidine with aluminum ions was determined,and the lowest extraction concentration of aluminum ions in the histidine complexation extraction solution,CAl=0.0539±0.003 g/L,and?(Al/RE)=52.19,was studied by multiple extractions,indicating that the aluminum ions in the mixed solution could be effectively separated from the rare earth ions when using histidine as a complexing agent in combination with the cloud point extraction method.4?Low concentration of hydrochloric acid was used as the extractant to reverse extract aluminum ions from the nonionic surfactant Triton X-114,and the effects of the volume fraction of the extractant,comparison,reaction temperature and equilibrium time on the reverse extraction effect were investigated.The results showed that when 1+11 v/v hydrochloric acid was used as the extractant,the reverse extraction rate of aluminum ions could reach 90.46%at a temperature of 40°C,compared with O/A=1:7 and an equilibration time of 10 min.At this time,most of the aluminum ions in the organic phase had been reverse extracted,and the Triton X-114 nonionic surfactant could be reused as an extractant.This research provides a new idea and method for rare earth aluminum removal technology,and the PBTCA process of aluminum ion separation has the advantages of simple operation,fast filtration and good separation effect.The extraction and separation of aluminum ions from rare earths by amino acid selective complexation and turbidity point extraction method has the advantages of novel method and good separation effect in one extraction,and the combination of organic complexation and turbidity point extraction technology provides a new research idea for the removal of aluminum ions from mixed rare earths. |
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