A process for the recovery of gallium from gallium arsenide scrap

The recovery of gallium (Ga) from gallium arsenide (GaAs) scrap using a leaching-ion exchange method was investigated. The ground GaAs scrap was leached, using 2.0 N nitric acid at 30 °C for 1.0 h, and the dissolution of Ga and arsenic (As) reached 98%. The pregnant solution with a 1/20 dilution ratio was then passed through a weak acid chelating resin Diaion CR-11. Highly charged Ga³⁺ has the ability to form complexes with the chelating resin and separate from the coexisting H₃AsO₄ in the leachate with very low pH. The loaded column was eluted with 0.1 M H₂SO₄, and the final concentrated solution had 4.5 g/L of Ga with 99.3% purity. The euent from the column was further processed to remove As by ferric arsenicate precipitation, and reused continuously as the dilution water for raw leachate.