Alkali Leaching Of Indium From Indium-poor Materials Under Ultrasound

Rare metal indium,indispensable in high-tech fields such as semiconductor,aerospace,and information industry.However,with the wide application of indium,the raw materials available for extracting indium are drastically reduced.the recovery of indium regeneration resources has gradually become an important source of indium extraction.At present,the extraction of indium from solid waste containing indium is generally carried out by acid leaching,which has problems such as accompanying components and difficulties in subsequent separation.Indium is an amphoteric substance,and it can be effectively extracted if it can be subjected to alkaline leaching by means of additional strengthening means to separate indium from many accompanying components.Based on this,the artificial zinc indium ferrite(indium content w=0.09wt%)was taken as the research object,and the indium was leached from the indium-depleted material under the condition of ultrasonic strengthening by alkaline leaching.The basic physicochemical properties of zinc indium ferrite compounds were studied.The leaching behavior of indium in indium-free materials without external field conditions,the leaching behavior of indium in indium-poor materials under ultrasonic field,and the effect of coexisting components on indium leaching rate were studied.The following main conclusions are drawn.(1)The optimum calcination temperature of zinc indium ferrite is 1000 ° C,and the optimum calcination time is 1 h.Indium enters the octahedral lattice of zinc ferrite during high temperature calcination.The zinc indium ferrite particles under the optimum calcination conditions are relatively smooth and irregular in shape,relatively uniform,and have a particle diameter of about 0.5 to 1 ?m.(2)Under the condition of no external field,the optimum process conditions for indium alkaline leaching are: leaching time 2h,leaching temperature 30 °C,stirring speed 400r/min,raw material particle size 160-200 mesh,material-liquid ratio 1:20g/mL The concentration of sodium hydroxide is 11 mol/L.Among them,the concentration of sodium hydroxide has the greatest influence on the leaching rate of indium.The morphology of the leaching slag is similar to that of the unleached zinc indium ferrite,which is a relatively uniform irregular spherical particle with no obvious change.Under the same conditions,the indium leaching rate of acid leaching is higher than that of alkaline leaching.The leaching rate under acidic conditions is 46.85% after leaching for 150 minutes,and the leaching rate under alkaline conditions is 35.63%.However,acid leaching has the problem of subsequent separation.(3)Under the same conditions,the leaching rate of indium under ultrasonic is81.37%,while the indium leaching rate under ordinary water bath heating is 54.67%.The ultrasonic field can significantly increase the leaching rate of indium.The leaching rate of indium increases with the increase of ultrasonic power.When the ultrasonic power is 100 kw,the leaching rate of indium reaches 81.32%.Since the basicity of potassium hydroxide is stronger than that of sodium hydroxide,the indium leaching rate of potassium hydroxide as a leaching agent in the ultrasonic field is slightly higher than that of sodium hydroxide.Under the ultrasonic field,the sample leaching slag appears as flaky particles with a particle size of about 1 ?m,which is quite different from the sphere without leaching slag from the ultrasonic field.It can be seen that the ultrasonic field has a great influence on the particle morphology of the leaching slag.(4)The order of influence of Si,Al and Mg coexisting components on indium leaching rate is: Al>Mg>Si.Among them,the indium leaching rate decreases with the increase of alumina mass fraction,and the decrease is about 25%;the indium leaching rate decreases with the increase of magnesium oxide mass fraction,and the decrease is about 10%;the indium leaching rate increases with the silica mass fraction.No significant change was seen,only about 3%.