A new process for preparing feed-grade zinc oxide from zinc oxide ore by acid leaching, transformation, zinc precipitation, filtration, washing and drying was studied. The effects of acid leaching, impurity removal conditions, calcination temperature and time on the product quality were investigated.
This research belongs to a new technology of preparing feed-grade zinc oxide by total wet method. It has the advantages of cheap raw materials, strong adaptability and low production cost. The quality of the prepared product can reach the first-grade standard of feed-grade zinc oxide HG/T 2792-1996. This method makes full use of the low-grade zinc resources and has a good application prospect.
Feed grade zinc oxide is an important feed additive, which is white or yellowish hexagonal fine powder. Compared with feed grade zinc sulfate monohydrate and zinc sulfate heptahydrate, feed grade zinc oxide has the characteristics of tasteless, non-toxic, delicate quality, high content of trace element zinc and fine product. Its biological utilization rate is high and it is a good source of zinc. Compared with other zinc sources, the cost of zinc oxide per unit is obviously lower, which is beneficial to reducing the cost of feed additives. The addition amount of zinc oxide is equivalent to 44% of zinc sulfate monohydrate and 28% of zinc sulfate heptahydrate.
The results showed that zinc 2000-3000mg/kg from feed zinc oxide could promote growth and antimicrobial activity of piglets, increase to a reasonable amount, and could replace antibiotics. Therefore, as a good additive of trace element zinc in feed and a substitute of some antibiotics, feed zinc oxide will have a good market prospect. Feed-grade zinc oxide was prepared from zinc oxide ore by acid leaching, conversion, precipitation transformation, filtration, washing, drying, calcination and other processes, which met the HG/T 2792-1996 (first-class) standard.