Research On Purification Of Scattered Metal Gallium Based On Electrolysis

With the widespread application and development of the electronics industry,metal gallium has gradually become a high-tech support material.High-purity gallium and its series of compounds have gradually been widely used in optoelectronics,new energy,integrated circuits and other industries.At present,high-purity metal gallium is produced by electrolytic refining to obtain gallium-rich lye after enriching the circulating mother liquor from alumina production.However,while producing high-purity gallium by various purification methods,it is easy to cause some of the remaining gallium after purification not to be processed and waste gallium resources.In response to this problem,this thesis recycles the 3N raw material gallium based on electrolysis.First,the gallium-rich alkaline electrolyte is prepared from the raw material gallium by electrolysis,and then the raw material gallium is purified by the electrolytic purification method,and finally the gallium ions in the gallium-rich alkaline solution are recovered.By investigating the electrolysis conditions such as current density,electrolysis temperature,electrode spacing,stirring speed,and electrolysis time,the current efficiency,gallium ion concentration and cathode potential were used as the criteria to select the best electrolysis conditions.(1)Purification of electrolyte The purpose is to use high current density for preelectrolysis to purify the electrolyte,so that the content of impurity elements such as Zn、Fe、Pb n Ni,etc.which have a higher standard electrode potential than gallium in the electrolyte is reduced,and at the same time,the electrolyte is rich in Gallium ions create a suitable electrolysis environment for subsequent electrolysis purification.In the process of purifying electrolyte,3N gallium is used as the raw material,and the best electrolysis conditions are selected by investigating the current efficiency and the gallium ion concentration.The best electrolysis conditions for purifying electrolyte are:current density 0.20 A/cm2,sodium hydroxide concentration 150 g/L,electrolysis temperature 45℃,stirring speed 250 r/min,electrode spacing 3 cm,electrolysis time 8 h.The current efficiency of the electrolysis process is about 63.94%,and the gallium ion concentration is about 28 g/L.(2)In the electrolytic purification process,based on the above-mentioned purified electrolyte,the anode is the raw material gallium,and the cathode is high-purity gallium.The influence of appropriate electrolysis conditions on gallium electrolytic deposition is explored,and the raw material gallium is purified.The best electrolysis conditions for electrolytic purification of gallium are:electrode form SUS316-SUS316,current density 0.08 A/cm2,electrolysis temperature 50℃,stirring speed 20 r/min,electrode spacing 3 cm,electrolysis time 12 h.At this time,the cathode potential of the electrolysis process is about-2.32 V,the current efficiency is about 91.53%,and the gallium ion concentration is about 33.76 g/L.After electrolysis,the content of impurity elements in the gallium after electrolysis is significantly reduced by ICP-MS.Among them,the impurity removal rate of Cr is higher,about 99.78%.It can be calculated that the purity of gallium in the sample after electrolysis purification basically reaches 5N.(3)In the electrolyte after electrolysis,the concentration of gallium ions and sodium hydroxide is higher.Therefore,electrolysis is used to recover gallium ions in the electrolyte.The best electrolysis conditions for recovering electrolyte are:current density 0.06 A/cm2,electrolysis temperature 55℃,stirring speed 20 r/min,electrolysis time 16 h,at this time,the current efficiency of recovered electrolyte is about 72.95%,and gallium in the electrolyte The recovery rate is about 78.83%.