Study on Leaching and Purification of Indium-Rich Slag
The process of"first stage of low acid deimpurity,second stage of high acid leaching indium,iron powder reduction purification,vulcanization precipitation purification"was adopted to recover valuable metal indium from indium-rich slag.The optimum parameters of the first stage of low acid deimpurity are as follows:oxidizer 40 mL/L,terminal pH=2.0,liquid-solid ratio 5∶1 and temperature 70℃,the removal rate of copper and zinc in indium-rich slag can reach more than 95%,the removal rate of iron can reach more than 55%,and the loss rate of indium is less than 1%.The optimum parameters of the second stage high acid leaching of indium are as follows:oxidizer 100 mL/L,initial acid concentration 350 g/L,temperature 75℃and reaction time 2.5 h,the recovery of indium can reach 95%above.The optimum parameters of iron powder replacement and sulfide precipitation step purification are as follows:iron powder 4.5 g/L,sodium sulfide dosage 1.0 times the theoretical value,reaction temperature 60℃and reaction time 80 minutes,the removal rate of copper,arsenic,tin and other impurities can reach more than 95%,and bismuth removal rate can reach 85%above.The recovery of indium in the purification process can reach more than 97%.
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