GaAs chlorination study

摘要

The compound GaAs is at the present time an essential part of electronic devices. The recovery of elements from electronic wastes is fundamental for the metallurgic industries. In this work, the following reaction is investigated: GaAs + 3Cl2(g) → GaCl3 + AsCl3 With the aim of recovering constituent elements by chlorination, several variables were studied such as: chlorine partial pressure, in the range between 0.2 and 1 atm, by dilution with N2; and temperature of reaction, in the -29°C to 200°C range. The reagents used were GaAs of analytical quality, chlorine and nitrogen gas of high purity. The reagents and products were analyzed by X-ray fluorescence (XRF), X-ray diffraction (XRD), scaming electronic microscopy (SEM) and atomic absorption spectofotometry (AAES). The results show that the rate of chlorination did not change significantly with the temperature, but increased with the chlorine partial pressure. It was found that AsCl3 was partially evaporated at temperatures above 20°C, while the GaCl3 start to be evaporated at 100°C. These partial results show that chlorination is a selective and economic methodology for the recovery of gallium from electronic wastes.