羟肟萃取剂LIX984N酸解和铜萃取分相性能

摘要

铜溶剂萃取时,萃取剂与硫酸溶液接触将促发其降解.研究羟肟萃取剂LIX984N的酸解行为及其对萃取分相性能的影响.结果表明:酸降解使肟基结构破坏,LIX984N中5-壬基水杨醛肟降解生成2-羟基-5-壬基苯甲醛、2-羟基-5-壬基乙酰苯酮肟降解生成2-羟基-5-壬基苯甲酮;有机相与浓硫酸溶液接触30 h后,萃余液表面张力从56.4 mN/m降至38.1 mN/m,铜萃取分相速率明显降低,萃余液中有机相夹带量、溶解量显著增大,有机相流失现象加重.研究发现夹带是萃余液中有机相流失的主要形式,接触50 h时夹带量在有机相流失总量中占61％.%The degradation of oxime extractants is triggered once contacted with sulfuric acid solution in copper solvent extraction practices.The degradation of LIX984N and its impacts on the phase disengagement in copper solvent extraction were investigated.The results show that the molecular structures of both oximes in LIX984N are broken due to degradation.The 5-nonyl salicyaldehyde oxime and 2-hydroxy-5-nonyl acetophenone oxime degrade to 2-hydroxy-5-nonyl benzaldehyde and 2-hydroxy-5-nonyl acetophenone,respectively.The surface tension of the raffinate decreases from 56.4 mN/m to 38.1 mN/m,and the phase disengagement speed drops down obviously when the organic phase is mixed with the strong sulfuric acid solution for more than 30 h.Meanwhile,the levels of the entrainment and dissolution of organic chemicals in the raffinate increase largely.As a result,the more organic chemicals loses during the course of solvent extraction.It is found that entraining is the main way for the losses of organic chemicals in the raffinate.The amount of organic chemicals loses by entrainment accounted for 61％ for the total losses in 50 h.