First, the ammonia leaching method is used as a technical means for the effective treatment of acid leaching slag, and the nano nitrite powder is prepared under a weak alkaline ( Ή 8 8.5 to 10) ammonia environment. In an alkaline environment, some metal impurities such as The solubility of Ca, Mg, Fe and Al hydroxides is low, and the impurities entering the final immersion liquid in the selective leaching of ammonia-ammonium sulfate are reduced, thereby ensuring the quality of the product; the traditional acid method for preparing lithopone is because of the zinc calcination. In the roasting and reduction process of the alkalized alkali, the elemental sulfur and sulfite are more or less produced, and the prepared white powder has a yellowish color, and the metathesis reaction of the patent is carried out in an ammonia solution (alkaline). The final product obtained is sulfate, which is quickly and thoroughly added by desulfurization through 3⁄40 2 , and the whiteness of the product can be ensured without high temperature calcination; the equipment requirement is lower than that of sulfuric acid leaching, and the ordinary steel leaching tank can complete the leaching; The environmental pollution problem of acid leaching residue, especially effectively solves the environmental pollution of heavy metals such as zinc, copper, lead, cadmium and arsenic in acid leaching residue and the influence of acid ions on the storage environment. Realize the recycling of high-value metal zinc in acid leaching slag, realize the acidity improvement of soil and have the comprehensive advantages of low cost, energy saving and environmental protection.
