Reserach On The Process Of Removing Lead And Zinc From High Concentration Rare Earth Chloride Solution

With the development of high technology,the application fields of high-purity rare earth materials will be further expanded and developed,and their quality requirements will gradually increase.At present,the problem is that the purity of rare earths is not high enough.The main reason is that rare earth minerals contain a large amount of impurity ions,which makes the extraction process of rare earth elements difficult.Therefore,a good impurity removal process has been invented to make other impurities in the rare earth solution.Reaching the minimum content,thereby improving the purity and recovery rate of rare earths,has become a necessary research topic.In view of the above problems,this subject adopts two methods to study the separation of impurities such as lead and zinc in high-concentration rare earth solutions:Based on the traditional sodium sulfide method,after the lead and zinc impurities in the rare earth solution are settled with ammonium sulfide,the influence of the added sulfide ions is further removed by the centrifugal sedimentation method.The experimental results show that when the temperature is 50℃and the time is 30min,the content of lead and zinc is detected by ICP-OES.The lead content decreased from 0.768g/L to 0.017g/L,and the lead removal rate reached 97.8%;the zinc content decreased from 0.30g/L to 0.0001g/L,and the zinc removal rate reached 99.9%.The rare earth content was measured by the cerium determination method,the rare earth content decreased from 273g/L to 267.7g/L,and the rare earth loss rate was 1.95%.After centrifugal sedimentation,the sulfide ion concentration dropped to 0.029g/L,and the concentration of the original solution was 0.043g/L.After centrifugal sedimentation,the influence of sulfide ions in ammonium sulfide on the rare earth solution is removed.The electrolysis method is used to study the effect of high concentration rare earth chloride solution on removing lead.The experimental results show that the cathode plate is selected as stainless steel mesh,the distance between the plates is 4cm,the temperature is 50℃,and the current density is 0.8A/dm~2.The time is 12h,and the lead content is reduced from 0.768g/L to0.0045g/L under the condition of air stirring.The lead is removed by electrolysis,and the rare earth loss rate is 0.The cathode product is analyzed by XPS detection,and the lead obtained from the cathode can be recycle.