中国有色冶金

During pyrometallurgical processes, thallium is easily volatilized and entered into flue gas scrubbing operations, resulting in a large amount of thallium-containing wastewater and posing environmental pollution risks. Additionally, millions of tons of leaching residue waste, mainly composed of ZnFe2O4, are generated in the lead-zinc industry. Therefore, this study proposes the Preparation of high-efficiency thallium adsorption materials from zinc leaching residues. Initially, the zinc and iron are extracted from the residues using an acid leaching method. Thereafter, iron is separated from the leachate through a selective precipitation process. Ultimately, the iron precipitate is subjected to freeze-drying to produce thallium adsorbent. The counter-current leaching method achieves high leaching efficiencies of zinc and iron(Zn: 97.05% and Fe: 99.31%). The concentrations of zinc and iron in the leachate are 86.54g/L and 77.86g/L, respectively. The selective iron precipitation process is capable of precipitating 99.78% of the iron from the leachate, with the zinc loss controlled to below 0.5% concurrently. Upon treatment with the freeze-drying process, the iron precipitate exhibits exceptional performance in the adsorption of thallium, achieving a removal rate of 98.9% in an aqueous solution with a concentration of 3g/L thallium. A dilute hydrochloric acid solution with a pH value of 1.5 can desorb 95% of the adsorbed thallium, providing favorable conditions for the further recovery and resource utilization of thallium. This process not only achieves green and high-value recovery of zinc leaching slag but also successfully prepares an iron-based thallium adsorbent with competitive performance.