Evaporation Behaviors of Cu(In,Ga)Se₂ Semiconductor Compound via Pyrometallurgical Chlorination Process Utilizing Ammonium Chloride

抄録

The chlorination process utilizing ammonium chloride as chlorination reagent has been employed for the recovery of elements from a promising photovoltaic semiconductor material, copper indium gallium diselenide, Cu(In,Ga)Se₂, through vaporization of the chlorides of the elements. It was found that the chlorination took place by heating of the model sample in the presence of ammonium chloride. The influence of process parameters, such as oxygen partial pressure in the gas phase, the composition of ammonium chloride and the reaction temperature, has been investigated. The increase in the oxygen partial pressure resulted in the substantial increase in the recovery. The chlorides of indium and gallium deposited in the temperature zone around 400 K, while selenium chloride concentrated in the lower temperature zone below 320 K, for the reaction at 673 K. Copper was detected mostly in residue. At 1073 K, on the other hand, the evaporation of copper chloride was observed. These phenomena result from the difference in vapor pressure of metal chlorides.