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 86.54 g/L and 77.86 g/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 3 g/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.
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