Extraction Of Gold And Platinum From Hydrochloric Acid Medium By Pyrrolidine Ionic Liquid

Precious metals play an important role in many fields such as military,economic and industrial because of their good physical and chemical properties.Ionic liquids,as an excellent extractant,have a good extraction effect on precious metals and are used in the field of extraction and separation.In this paper,we mainly synthesize pyrrolidine ionic liquid and construct it into liquid-liquid extraction system to realize the extraction and separation of precious metal gold and platinum.The main research contents are as follows:We synthesized the ionic liquid[C6CiPyr]Br and dissolved it in chloroform as an organic phase to extract Au(?)and Pt(IV)respectively,and the effects of different extractant concentrations,HC1 concentration and extraction temperature were explored.Under the optimal extraction conditions,the extraction efficiency of[C6CiPyr]Br to Au(?)and Pt(?)can be achieved 99.5%and 95%.At the same time,we realized the complete separation of Au(?)and Pt(IV)by using the different solubility of[C6C1Pyr]Br-Au(?)and[C6C1Pyr]Br-Pt(IV)in the organic phase.In addition,the anion exchange processes of the extraction of Au(?)and Pt(?)with[C6CiPyr]Br were determined by spectral analysis and theoretical calculations.Selective extraction experiments showed that[C6CiPyr]Br has high extraction selectivity for Au(?)and Pt(IV),while the extraction efficiency of other metals are less than 10%.The Gemini ionic liquid[Cn-6-CnPyr]Br2(n=6,8,10)was synthesized and applied to the extraction of Au(?)for the first time.The effect of extraction on Au(?)was investigated by changing the length of the hydrophobic chain.The results show that for[Cn-6-CnPyr]Br2(n=6,8,10),the growth of alkyl chain is favorable for extraction.Under the optimal extraction conditions,the extraction efficiency of Au can be reached 98%by exploring the effect of[C,-6-CnPyr]Br2 concentration,phase ratio and HCl concentration on the Au(?)extraction behavior.In addition,acid resistance and selectivity tests showed that[Cn-6-CnPyr]Br2 has good acid stability and extraction selectivityThe hydrophobic ionic liquid[C2n+2On(Pyr)2][NTf2]2(n=1,2)was synthesized and used to extract Au(?).Since[C2n+2On(Pyr)2][NTf2]2 is insoluble in water,we use it to extract gold from the aqueous phase without adding solvent.The optimum amount of metal was determined by measuring the influence of metal concentration on the extraction efficiency.The molar amount of[C22n+2On(Pyr)2][NTf2]2 and Au(III)in the extraction which is 1:2 was estimated by calculation of extraction capacity.In addition,combined with spectral analysis,the mechanism of the extraction process was determined to be an anion exchange mechanism.Finally,the gold was stripped by oxalic acid and the regeneration of[C2n+2On(Pyr)2][NTf2]2 was achieved.