PURPOSE: To effectively recover In as crude In from high-In scrap essentially consisting of P, As, Ga, and In.
CONSTITUTION: This method for recovering the indium from the indium scrap contg. the phosphorus, arsenic, gallium and oxygen as impurities consists in adding sodium hydroxide of the equiv. weight of 5 to 20% of the weight of the plus sieve obtd. by pulverizing and classifying this scrap by a wet process to this plus sieve, heating the scrap to 200 to 300°C to melt the scrap, then separating the scrap to soda slime and crude indium metal, subjecting the soda slime and the minus sieve obtd. by the above-mentioned classification to oxidation leaching with the acidity of hydrochloric acid and recovering the indium in the resulted leaching liquid as the crude indium metal from the leaching liquid. The crude In is efficiently produced from the high-In scrap contg. the P, As and Ga generated in association with the production of semiconductors as the impurities.
MINAMI CHIAKI
TAKEI KAZUHIKO
