Feed grade zinc oxide has the same physical and chemical properties as zinc oxide used in other industries.
The appearance of forage grade zinc oxide is white or slightly yellow powder, the molecular weight is 81.4, the relative density is 5.61 g/L, the stacking density is about 0.2 ~ 2.0g/L, slightly soluble in water, is amphoteric oxide, can react with acid and strong alkali, can absorb carbon dioxide and water in the air into basic zinc carbonate. The chemical properties of feed grade zinc oxide do not change with the production process and use, but the physical characteristics will be very different.
As a result of the mutual supporting effect of powder material stacking, its weight per volume is much smaller than that of crystal state, so the concept of stacking density is generated.
Feed grade zinc oxide is used in piglets to prevent diarrhea caused by stress in weaned pigs and also to improve feed remuneration.
Long-term practice has proved that the zinc source in the form of zinc oxide has special effects on anti-diarrhea in weaned pigs, while the soluble zinc sulfate has no obvious effects.
Feed grade zinc oxide can react with gastric acid in the stomach and also interfere with the effect of acidifier. It reacts with gastric acid and becomes zinc chloride, which reduces the function of zinc oxide as an anti-diarrhea agent.
Standard of feed grade zinc oxide: the production or sale of feed grade zinc oxide in China must meet the regulations of industry standard HG/ t2792-2011, that is, the content of zinc oxide shall not be lower than 95, the content of zinc shall not be lower than 76.3, the heavy metal content of lead shall be no more than 20ppm, arsenic no more than 8ppm and cadmium no more than 5ppm.
The standard of feed grade zinc oxide has no requirements on the production process, but in general, most of the manufacturers are wet production, because the hygiene indexes of direct and indirect methods are difficult to meet the control requirements of heavy metals.
Of course, this is not absolutely, like the feed grade zinc oxide exported to southeast Asia, but also produced by fire (dry) method, because they have very low requirements on heavy metals, only look at the content of zinc oxide.
In Japan, the control of feed zinc source is quite strict, so it is usually produced by wet method.