Optimized gallium extraction from Bayer liquor using ion exchange: Experimental modeling in batch mode and demonstration in continuous columns

• Optimized gallium recovery from Bayer liquor using batch and continuous ion exchange. • Applied Response Surface Methodology to enhance selectivity and process efficiency. • Achieved 31.7% gallium recovery with minimal vanadium co-extraction (7.8%). • Identified CH100 resin as the most effective for gallium extraction and Ga/V selectivity. The extraction of rare metals from industrial waste streams is gaining prominence in modern metallurgical research. This study focuses on the selective recovery of gallium from Bayer liquor, a byproduct of the alumina refining process, utilizing TY-CH550 first optimised in batch and subsequently validated in a 40 L fixed-bed column together with comparative tests on commercial resins. A systematic investigation was conducted to evaluate the impact of key operational variables, including contact time (20–240 min), temperature (30–60°C), sodium hydroxide concentration (211–311 g/L), and Bayer liquor-to-resin ratio (25–400 mL/g), on the extraction efficiencies of gallium and vanadium. Employing Response Surface Methodology (RSM) with a Central Composite Design (CCD), the study identified optimal conditions that maximized gallium recovery (31.7%) while minimizing vanadium co-extraction (7.8%). Applying these parameters to the fixed-bed column, sequential adsorption-washing-desorption-precipitation steps processed 40 L of industrial liquor and recovered impure gallium hydroxide with 95 % elution in 30 min, confirming proof-of-concept scalability of the batch-derived conditions. The column run further revealed a usable resin capacity of 0.42 mmol Ga g⁻¹ and stable breakthrough behaviour over 750 min. Comparative screening of commercial resins highlighted CH100 as the top performer, achieving 61.7 % gallium extraction and high Ga/V selectivity under identical batch conditions. These results demonstrate a coherent optimisation-plus-demonstration workflow and provide actionable metrics for the sustainable recovery of gallium from Bayer liquor.