Sustainable Mining and Metallurgy

Active Ti (IV) salt was used in tests to separate and recover As and Bi from the white dust leaching solution, test conditions of As adsorption and desorption were optimized, and the impact of recycling adsorbent on As adsorption was investigated. The test results demonstrate that active Ti (IV) salt can adsorb As in the white dust leaching solution and the optimal test conditions are the liquid-solid ratio of 14∶1, reaction temperature at 60℃, agitation speed at 100r/min and reaction duration of 1.5h. Under such conditions, the As concentration of leaching solution can drop from 8.33g/L to 0.69g/L, achieving an As removal rate of 91.7% and Bi loss rate of less than 2%. The optimal test conditions for desorption of As-loaded adsorbent are the liquid-solid ratio of 3∶1, sodium hydroxide concentration of 80g/L, reaction temperature at 40℃, and reaction duration of 0.5h. Under such conditions, the As desorption rate reaches 99.1%. The regenerated adsorbent of titanium salt can still remain quiet active even after 5 cycles of adsorption and desorption. When the amount of iron powder reductant added to the solution after As removal is 1.2 times the theoretical one, sponge Bi with purity higher than 92% can be obtained and the total recovery rate of Bi can surpass 95%. These tests have accomplished separation of Bi and As from the hydrochloric acid system, shortened the process flow of Bi recovery, and provided a new method for treatment of As-containing solution from nonferrous metallurgy.