Emulsion Liquid Membrane Technology In Separation Of Copper-Nickel From Ammonia Solution And Extraction Of Cadmium From Acidic System

In nature,copper and nickel elements are adjacent to each other,and their chemical properties are similar.They are often accompanied by existence.The efficient separation of them has always been a hot spot in the field of metallurgy.As a heavy metal,the harm of cadmium has attracted the attention of all countries in the world.It is urgent to treat cadmium wastewater efficiently,and the research and development of economical and applicable methods is the top priority.Emulsion liquid membrane（ELM）is one of the potential alternatives to solvent extraction technology.Compared with solvent extraction,ELM technology has many attractive advantages,including the integration of extraction and stripping processes in one step,high extraction efficiency,low chemical consumption,simple operation and low energy consumption.The ammonia leaching method enables copper and nickel in low-grade ore to be immersed in the solution in the form of ammonia complex ions,while other metal ions do not react with ammonia,thereby separating copper and nickel ions from other metal ions.Because copper and nickel ammonia complex ions have similar chemical properties,their efficient separation is a problem in hydrometallurgy.In this paper,the emulsion liquid membrane technology is used to study the separation of copper and nickel in ammonia solution,and a good separation effect has been achieved.At the same time,for the treatment of cadmium ions in wastewater,bifunctional ionic liquids[A336][P507]and[A336][P204],and studied the extraction and separation of cadmium using emulsion liquid membranes with them as carriers.（1）In the study of ammonia extraction and separation of copper and nickel,the influence of surfactant concentration,emulsification speed and emulsification time on the stability of liquid membrane was studied.and the Design Expert surface response was used for parameter analysis.Optimize selection.Studies have shown that the stability of the emulsion liquid membrane is as high as 82%under the optimal conditions of 6 vol.%surfactant,2000 rpm emulsification speed,and 17 min emulsification time.On the basis of the stability study,the separation effect of the M5640 system on the copper and nickel in the ammonia system was further studied.Under the optimal conditions,that is 6 vol.%of surfactant,1.5 vol.%of liquid paraffin,24 vol.%of M5640 extractant,internal phase 2 mol/L H₂SO₄,oil internal ratio of 1:1 The ratio of emulsion to water is 1:3.After 10 minutes of reaction,The separation factor of Cu and Ni is 98000,and the separation performance of copper and nickel is good.Using infrared and other characterization methods to study the separation mechanism of copper and nickel,the results show that the difference in the extraction kinetics of copper and nickel by M5640 is the main reason for the separation of copper and nickel in ammoniacal solution.（2）The extraction performance of the emulsion liquid membrane with ionic liquid[A336][P507]as the carrier for cadmium was studied.The emulsion liquid membrane was prepared with sodium hydroxide as the internal phase（0.2 mol/L）,10vol.%Span80,1 vol.%paraffin wax and 15 vol.%[A336][P507]as the carrier,The experimental results show that the emulsion liquid membrane has a good extraction performance for cadmium.and the extraction efficiency of 100 mg/L Cd²⁺can reach98%.Similarly,[A336][P204]is used as a carrier to study the extraction of cadmium ions by the emulsion liquid membrane.Using sodium hydroxide as the internal water phase,10 vol.%Span80,1.5 vol.%paraffin,and 10 vol.%[A336][P204]as the mobile carrier to prepare the emulsion liquid membrane,the extraction rate of Cd²⁺can reach 94%.At the same time,combined with liquid-liquid extraction,the use of infrared characterization and other methods to study the extraction mechanism of cadmium,the results show that the synthesized functional ionic liquid can exchange reaction with Cl^-in Cd Cl₄^-.（3）The demulsification of emulsion liquid film is also studied in detail in this article.Separately studied centrifugation,heating,demulsifier,centrifugal-heating combined demulsification,and demulsifier-heating combined demulsification.Experimental studies have shown that the use of demulsifiers in the copper-nickel system has the best demulsification effect,and the demulsification rate can reach 92%.The extractant after demulsification can be reused at least 5 times.The effect of using a single method in the cadmium ion system is not ideal,and the demulsification rate can be as high as 94%through the combined demulsification of demulsifier and heating and the combined demulsification of heating and centrifugation.