China Nonferrous Metallurgy

A significant amount of waste is generated during the production of gallium arsenide. The recovery of the galliumbecome one of the critical research topics.This paper ingeniously integrates the advantages of various gallium arsenide waste recovery processes and proposes an innovative leaching-extraction-electroplating process. In this process, using gallium washing hydrochloric acid solution as the leaching solution. Based on a meticulous analysis of the mechanisms of leaching, extraction, and electroplating, comprehensive relevant conditions were thoroughly tested, and the following principal conclusions were obtained. In the low acid condition (pH of 1mol/L) of the washing gallium hydrochloric acid solution, the extraction system potential was controlled by regulating the gradient of temperature rise. The arsenic extraction rate up to 96%, and the gallium extraction rate surpassed 97%under the conditionsoffinal leach temperature 75℃, leach time 4h. Using P204 as the extractant, gallium extraction rate was above 99% with two-stage extraction. Notably, the extractant demonstrated no extraction effect on arsenic,andthe separation efficiency of gallium and arsenic exceeding 99%. The stripping was conducted using 150g/L NaOH as the stripping agent with an O/A ratio of 2/1, and the gallium stripping rate was above 99.9%. By adding 0.15g/L EDTA to the stripping solution, the current efficiency was significantly increased from 41% to 78%.Post-electricity was recycled to using as the stripping solution,the gallium leaching rate remained stable at 97%, the gallium extraction rate was consistently at 99.6%, the stripping rate was stay at 99.9%, and the current efficiency was steadily at 78% after three successive recycling experiments.The gallium recovery rate reaching 96% and there is no toxic gas of hydrogen arsenide produced in this process.