Extraction Of Copper And Cadmium With ?-Aminophosphonate Extractant

Industrial waste water,which contains a large number of heavy metals such as copper,cadmium,zinc,cobalt and nickel,causes great harm to the environment.And the demand for high-purity metals in industrial application is also increasing.Therefore,it is necessary to find an efficient separation and purification method for recovering heavy metal ions from industrial waste.In recent years,solvent extraction has become a significant method for metals separation and has been widely studied to extract and recovery metals ions based on the advantages of high efficiency,strong adaptability,simple equipment and large-scale production.In this paper,the extraction behavior of Cu(II)and Cd(II)from hydrochloride solution was investigated using ?-aminophosphonate extractant and the probable extraction mechanism was proposed,which enrich the theoretical basis for the development of solvent extraction.The main work is as follows:1.For comparison,two different extractants was used to study the extraction of copper(II).And di(2-ethylhexyl)[N-(2-ethylhexyl)aminomethyl]phosphonate(Cextrant 230)was selected to extract copper(II)from hydrochloride solution.The effect of the concentration of extractant,acidity in aqueous phase,salting-out agent and temperature on the copper(II)extraction was investigated.The result shows that the extractant has a high extraction capacity for copper(II)in the presence of a salting-out agent.The extraction mechanism was proposed to be solvation mechanism and the extracted complex was also determined The extractant was applied to recover copper from the raffinate of NdFeB magnets after recovering rare earth.The yield of copper product reached 98.0% with the purity 99.5%.2.The extraction ability,loading capacity and reaction mechanism of cadmium(II)extraction from hydrochloride solution with Cextrant 230 were studied.The result shows that the extractant has strong extraction ability for cadmium(II).The extraction capacity of 30%(v/v)extractant for cadmium(II)was 26.42 g/L.The effect of temperature on the extraction process was discussed,and the corresponding thermodynamic parameters were calculated.It was found that the extraction process was an exothermic process.Cadmium(II)was easily stripped from loaded organic phase with nitric acid.And the stripping efficiency was above 95%.Cadmium(II)was completely recovered from simulated wastewater using the extractant with 3-stage cross-flow extraction.3.A new acidic extractant [(2-ethylhexylamino)methyl phosphonic acid mono-2-ethylhexyl ester] was obtained by hydrolysis of Cextrant 230.The extraction ability of acidic extractant for copper(II)and cadmium(II)from hydrochloride solution was studied.Comparing to Cextrant 230,the extraction property of copper(II)and cadmium(II)with the acidic extractant was not as good as the former.The extraction properties of the acidic extractant on the extraction and separation of cobalt and nickel from three different systems(sulfuric acid,hydrochloric acid and nitric acid)were also investigated.It was showed that the extractant was effective for the extraction and separation of cobalt and nickel from three different systems when the equilibrium pH value is above 4.5.