Separation of gallium from acid leachates of zinc smelting slag by tartaric acid coordinated complexation and anion-exchange

The rapid advancement of strategic technologies, including semiconductor manufacturing, 5G infrastructure, renewable energy systems, and aerospace engineering, has driven a surge in global demand for gallium (Ga). To address this need, secondary resources such as zinc smelting slag have emerged as a critical source for gallium recovery. This study proposes a novel strategy for gallium recovery by leveraging the ligand complexation capability of tartaric acid to convert Ga(OH)₃ into negatively charged complexes([GaO₂(OH)C₄H₂O₄]₂⁴⁻), followed by selective adsorption using a polystyrene-based anion-exchange resin (D201 × 7). The results demonstrated that the maximum adsorption capacity was 138 mg/g at pH 4, T = 328 K, t = 45 min and 1:1 M ratio of tartaric acid with Ga. The adsorption process conformed to the pseudo-second-order kinetic and Langmuir isotherm models. The primary mechanism for the adsorption of Ga(III) involved complexation with tartaric acid to form an anionic species and undergo ion exchange via the Cl⁻ functional groups on the D201 × 7 resin. The column experiment demonstrated highly selective adsorption efficiency of Ga(III) in the presence of various interfering metal ions. This study provides a feasible alternative for the separation of Ga(III) from industrial zinc slag processing in sulfuric acid systems and has broad application prospects.