REFINING METHOD FOR INDIUM

PURPOSE:To easily remove Si as impurity in In, by heating In containing Si as impurity in an oxidizing atmosphere to oxidize a part of In into In2O3 and also by heating the above in a vacuum atmosphere so as to oxidize impurity Si into volatile SiO by In2O3. CONSTITUTION:A vessel 1 composed of high-purity artificial graphite is placed in a quartz core pipe 1, and In containing Si as impurity is put into the above. While heating In in the vessel 2 up to 200-500 deg.C by means of a heater 7, an Ar gas containing O2 gas is introduced through a gas-introducing part 4, so that a part of In is oxidized into In2O3. Subsequently, the gas-introducing part 4 is blocked and the inside of the core pipe 1 is evacuated to 5X10Torr by means of an evacuating device 6, which is heated again up to 750-1,100 deg.C. Then, In2O3 in In is allowed to react with Si as impurity to oxidize Si into SiO excellent in volatility, which is removed by volatilization. In2O3 is reduced into In, so that In minimal in content of Si as impurity can be obtained.