The control of trace element premix raw materials is mainly to grasp three principles, namely: control of oxidation factor, control of caking factor and control of hygiene index.

It is well known that the most likely to cause color change in the trace element premix is iron. The light green divalent iron ions in the raw materials are oxidized to yellow trivalent iron ions, which causes the premix to change color. So, what causes the oxidation of iron ions, and how do we control this discoloration factor. Briefly summarized into three aspects. First, the control of oxidants in feed. As mentioned above, my country's feed-grade trace elements mostly come from industrial by-products. The production of feed-grade zinc sulphate is mostly made by wet method. The raw material used is zinc hypoxide from industry, which also contains other elements such as cadmium, lead, arsenic and iron. Therefore, in order to obtain high-content zinc sulfate products, impurity removal is required. In the impurity removal process, oxidant removal occupies an important position. The oxidant used for these impurity removal is mostly hydrogen peroxide, and a part of it is brought into the trace element premix with the zinc sulfate raw material, so the divalent iron in the trace element premix is oxidized to trivalent iron. Second, the choice of carrier. Many companies use stone powder as the carrier of the trace element premix. As the pH of the premix increases due to the stone powder, ferrous iron will be oxidized to ferric ions at pH>5. Third, the selected organic iron is not sufficiently chelated, and is oxidized to trivalent iron in a large amount under the action of free water in the premix. The method to solve the above problems is very simple. First, detect the residual amount of oxidant in each batch of raw materials. Second, select appropriate trace element carriers. Third, scientifically and effectively evaluate organic trace elements.

Agglomeration of premix is mainly caused by moisture absorption and recrystallization of raw materials. The main reason for this phenomenon is that a large amount of free water, free acid and chloride remain in the raw materials. The main methods to control agglomeration are as follows: First, strictly formulate corporate standards. Because the relevant national standards for trace element monomers control fewer indicators, they cannot rely on the national standards to select a high-quality raw material. It requires companies to meet their own needs and testing. Strength to formulate detailed corporate internal control standards. Second, strictly control whether the above three of all raw materials exceed the internal control standards of the enterprise. Third, minimize the use of copper sulfate pentahydrate.

On the basis of the national standard, the content of nickel and mercury needs to be additionally controlled, because nickel directly affects the skin coloration of young animals and poultry, and copper sulfate has the highest nickel element content. Mercury is very easy to damage the gastric mucosa and intestinal villi, leading to a decrease in digestibility and absorption rate. Therefore, it is necessary to focus on controlling whether the mercury element exceeds the standard in the diet of weaned piglets. Another important issue is the control of dioxins. Most of the raw materials for the production of feed-grade copper sulfate in our country use waste corrosion liquid from the production of circuit boards. The waste corrosion liquid used to produce circuit boards just has the three conditions for generating dioxins, namely: benzene ring, chloride ion and high temperature. Therefore, we tested the content of dioxins in the finished feed grade copper sulfate which exceeded the EU standard by 3 to 5 times. As we all know, dioxins are highly carcinogenic, and long-term use of high copper in piglet feed is bound to cause harm to the environment and humans.

Due to the low absorption rate of inorganic trace elements and the low price, the cost of the compound feed is very small. Therefore, manufacturers have always used inorganic trace elements in a proportion that exceeds the NRC and the national standard by 3 times or even higher. As we all know, there is a certain safety threshold for the use of trace elements, and there is also a certain proportion of absorption between the elements. Due to our large-scale use, animals cannot fully absorb it, resulting in a great waste of trace elements. At the same time, a large number of cations also cause a certain stimulus to the animal's intestinal electrolyte balance. Therefore, for the use of trace elements, we must focus on the two basic principles of effective content and the ratio of elements, and design animal trace element premixes of different varieties and stages with ideal trace element models.

When designing any animal's trace element premix, the following factors must be considered on the basis of the formula design principle: First, the loss caused by the redox reaction between different forms of trace elements. Second, the best addition ratio among the four elements of iron, copper, zinc and manganese. Third, the ratio of organic trace elements to inorganic trace elements. Fourth, whether different regions are in the lack of trace elements. Fifth, in different seasons, the safe amount of trace elements needs to be increased. Among them, the addition ratio of inorganic trace elements and organic trace elements is the most perplexing problem encountered by many feed companies in the design process. Here, the basic trace element application database and market application experience value owned by our production enterprises are extra important.

First of all, we must be clear about the characteristics of high-quality microelement premix, which can be summarized in five points. That is: First, make the micro-components evenly distributed. Second, improve the instability of trace components. Third, the level of addition can be standardized. Fourth, reduce the production process of feed enterprises. Fifth, to maximize the synergistic effect of trace components.

It can be seen from the above that uniform distribution ranks first, so how to make chemical substances with different bulk density, different moisture, and different particle sizes to be mixed uniformly, there is no doubt that there are two aspects, namely: ultra-fine pulverization of very small components of raw materials, and fully automatic Scientific application of pre-mixing equipment. According to the Poisson distribution principle, the premix product with a mixing uniformity (CV) <3% or less is required. At least 900 particles of this component in each sample can prevent errors in the nutrient supply and analysis results of this component. For example, sodium selenite, calcium iodate, and organic chromium in the premix of trace elements have very low levels of addition, and the effective dose is close to the toxic dose. Therefore, ultrafine pulverization is necessary to make the mixing uniform. At present, enterprises all use dry ball milling for crushing. The average particle size after crushing is 500-600 mesh.

The scientific use of fully automatic pre-mixing equipment greatly improves production efficiency and reduces raw material procurement costs for feed enterprises. It also strictly controls the safety and stability of the trace element premix. The central control system controls the feeding sequence of the raw materials in the formula to reduce the problems of multiple feeding and missed feeding due to manual feeding. Accurate micro-weighing can effectively control the feeding error of materials. The double paddle mixer can ensure that the uniformity of the material mixing is controlled below 3%.

While possessing scientific technology and sophisticated automatic premixing equipment, it must also have a set of refined quality control processes and traceability systems. The first is the determination of the mixing uniformity. The traditional determination of the mixing uniformity of the trace element premix is to detect the iron element in it. However, there are two problems in the detection of iron element. First, the proportion of iron element in the micro-ore is relatively large. , Can not fully reflect the uniformity of the multi-ore mixing. Second, the micro-ores prepared by some companies currently do not contain iron, so it is impossible to detect the iron to reflect the uniformity of the product. You can choose trace components such as iodine, selenium, and cobalt to judge the mixing uniformity index, which is more accurate.

The current use of trace element premixes, on the more important aspect, is to place the trust of the feed companies on the selected multi-mineral supplier brands. As a multi-mining producer itself, it is necessary to develop a detailed traceability system so that multi-mining is not a cold product placed in the customer’s warehouse, and the person in charge of the feed company must truly perceive this product. The real situation of every link from raw material procurement, formula design, pre-mixing processing, finished product testing, logistics. To this end, some companies in the market have also launched a product online traceability query system, so that customers can clearly understand the ins and outs of their products.