Wet production process for feed-grade active zinc oxide

Abstract

The invention discloses a novel wet production process for feed-grade active zinc oxide, belonging to the field of feed additives. The process comprises steps such as neutral leaching, ammonia leaching, acid leaching, primary purifying, secondary purifying, carbonization reaction, washing and filtering, drying, heating for decomposing, and the like. In the process, active zinc oxide is produced by directly carbonizing an acid immersion liquid and an ammonia immersion liquid, so that cheap zinc flue dust is utilized, ammonia water in the ammonia immersion liquid and ammonium hydrogen carbonateare taken as carbonization precipitating agents of the acid immersion liquid, ammonia water and ammonium hydrogen carbonate are not additionally used, an ammonia evaporation step is eliminated, and production cost is reduced greatly; the bulk density of the obtained active zinc oxide can be up to 0.9-1.1 g / cm<3> and even higher, the higher requirements of the feed additive industry on the fluidity and bulk density of active zinc oxide are met; and the moisture content is lowered, so that the drying cost on every ton of product is lowered by about 200 yuan.

Description

technical field [0001] The invention relates to a hydrometallurgy technology, in particular to a production process of feed-grade active zinc oxide. Background technique [0002] Feed-grade active zinc oxide is used as an additive in the feed industry to prevent weaned piglets from diarrhea, improve the apparent digestibility and growth rate of weaned piglets, and reduce mortality. And in the feed processing process, in order to mix evenly, the fluidity of the product is required to be good, and the bulk density should be close to other feed materials, that is, 0.9-1.0g / cm 3 , Hygienic indicators such as lead, arsenic, cadmium and other heavy metals are strictly controlled, and all these requirements make the production of feed-grade active zinc oxide more difficult. [0003] At present, the traditional production process of active zinc oxide includes acid leaching process and ammonia leaching process. The ammonia leaching method is to use ammonia water and ammonium bicarb...

AI Technical Summary

Problems solved by technology

The arsenic removal efficiency of this method is only 70%, and the precipitation and filtration of ferric hydroxide is relatively difficult

[0012] The existing process uses metal zinc powder to purify and remove cadmium in the first stage of purification and removal of cadmium. When most of the lead and cadmium are replaced by zinc powder, the metal cadmium is coated on the surface of the zinc powder, and the metal cadmium will be redissolved again if it is not separated from the solution. The cadmium content in the solution is too high. This process can only remove cadmium to less than 2ppm, and the fluctuation is large, resulting in too large fluctuations in the cadmium content in the product, which is difficult to control