Synergistic recycling method of arsenic-containing waste salt and arsenic sulfide slag

Abstract

The invention discloses a synergistic recycling method of arsenic-containing waste salt and arsenic sulfide slag. The method comprises the following steps: dissolving the arsenic-containing waste salt, and filtering to obtain an arsenic-containing salt solution; the method comprises the following steps: adjusting the pH value of an arsenic-containing salt solution to 2-3 by using dilute sulphuric acid, adding arsenic sulfide residues, carrying out oxidation-reduction reaction at 85-95 DEG C for 2-4 hours, and carrying out solid-liquid separation on a mixed solution to obtain leaching residues and an arsenic-containing leaching solution; adding elemental arsenic and sodium hydroxide into the arsenic-containing leachate, carrying out a reduction-neutralization reaction at 80-95 DEG C for 3-5 h, then adding benzyl chloride, continuing the reaction for 7 h, cooling, standing and separating the liquid to obtain a benzyl arsonic sodium solution, adding sulfuric acid to adjust the pH value to 2-3, and reacting for 1 h to obtain a benzyl arsonic acid product; and leaching residues are washed with water according to the liquid-solid ratio of 4: 1 and purified to be reused in the smelting process, and washing liquid is returned to be continuously used. By adopting the method disclosed by the invention, the arsenic recovery rate is greater than 95%, the sulfur purity is greater than 98.6%, the benzyl arsonic acid purity is greater than or equal to 95%, the arsenic discharge is reduced by more than 90%, the cooperative treatment cost is reduced, and meanwhile, waste recycling and pollution control are realized.

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