Abstract
Purification and reuse is a potential method of smelting waste acid disposal. High concentrations of fluoride and chloride in waste acid are harmful impurity and must be removed. Previous studies have shown that fluoride removal with rare earth and chloride removal with bismuth have similar cyclic process of "precipitation removal-agent regeneration" and similar reaction conditions. In this paper, a method of simultaneous precipitation removal of F− and Cl− from waste acid using La(OH)3 and Bi2O3 as a mixed remover was proposed, and the mixed remover is regenerated by sodium hydroxide solution for the recycling of the remover. Thermodynamic analysis of La3+-Bi3+-F−-Cl−-H2O system verified the feasibility of simultaneous removal. The experimental results showed that under the optimum reaction conditions, the removal efficiencies of F− and Cl− were 93.67 % and 96.47 %, respectively, and the concentrations of F− and Cl− in the solution after removal were 66.70 mg/L and 71.10 mg/L, respectively. Under the optimum conditions, the regeneration efficiencies of La(OH)3 and Bi2O3 were 96.80 % and 96.95 %, respectively. The proposed process has the advantages of no waste output, short process, and low energy consumption and provides an environmentally friendly method of removing fluoride and chloride from waste acid.
Published Version
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