Classification, advantages, production methods, storage packaging of zinc oxide
Classification of zinc oxide
There are many types of zinc oxide classification, you know a few, come and understand.
Zinc oxide can be divided into three major categories according to different production processes: A. Direct method (American law), B. Indirect method (French law) C. Chemical precipitation method (wet method).
Direct zinc oxide
The metal in the zinc-containing raw material is mainly present as an oxide such as zinc oxide, copper oxide, cadmium oxide or the like. When zinc oxide is reacted with coke, it is reduced to metal zinc by steam, and at the same time oxidized by oxygen in the air to zinc oxide, and most of the heavy metal is removed.
b. Indirect method zinc oxide
The metal zinc ingot or zinc slag obtained by smelting ore is converted into zinc vapor by heating, and is oxidized to zinc oxide by oxygen in the air.
c. Chemical (precipitation) zinc oxide
This method can be roughly divided into two types, namely, an acid method and an ammonia method. They use acid or alkali to react with the raw materials, and then purify them to obtain basic zinc carbonate. After calcination, the final product is light zinc oxide, or activated zinc oxide.
(a.) The acid method generally involves reacting a zinc-containing raw material with sulfuric acid to obtain a non-pure zinc sulfate solution containing heavy metal ions. Then, after oxidation and impurity removal, reduction and impurity removal, and multiple precipitation, a large amount of iron, manganese, copper, lead, cadmium, arsenic and the like are removed to obtain a pure zinc sulfate solution. This solution was neutralized with a soda ash to give a solid basic zinc carbonate. The basic zinc carbonate is washed, dried and calcined to obtain active zinc oxide.
(b.) The ammonia method usually uses ammonia and ammonium carbonate to react with the zinc-containing raw material to obtain a zinc-ammonium complex, and then removes impurities to obtain a qualified zinc-ammonium complex solution, and then passes through the ammonia to form a zinc-ammonium complex. Converted to basic zinc carbonate. Finally, the active zinc oxide is obtained by drying and calcining.
The above is the classification of zinc oxide introduced by the small editor, I hope to help you.
Advantages of zinc oxide
Zinc oxide is an essential additive in the rubber and tire industry. It is also used as a vulcanization activator and reinforcing agent for natural rubber, synthetic rubber and latex, and as a colorant. It can also be used in the chemical industry such as coatings, enamels, pigments, etc. It has good activation properties and is used more and more widely in rubber products, such as not only replacing the ordinary zinc oxide in the V-belt, but also reducing the number of The amount of /2-1/3 makes the various performance indexes of rubber stable, the vulcanization performance is not affected, and the production cost is reduced to replace the use of indirect zinc oxide in rubber products.
It has the following characteristics:
1. The active zinc oxide particles are fine and spherical, have large activity, have a large surface area, have good dispersibility and good adsorption, and thus can promote vulcanization of rubber. Activation and reinforcement anti-aging effect can strengthen the vulcanization process and improve the tear resistance and wear resistance of rubber products.
2. Small specific gravity and low content of harmful substances;
3. Active zinc oxide is easy to mix with the rubber compound, and the dispersion is uniform, which can improve the viscosity of the rubber compound, so the amount of active zinc oxide is less than that of ordinary zinc oxide;
4. It can improve the stability and thermal conductivity of the shape of the extruded product;
5. The performance of the NBR anti-aging agent;
6. Improve oil resistance;
7. Significantly reduce the cost of rubber compound, high yield and efficiency;
8. It can be used as a softening agent in a large amount to make the rubber compound not easy to be deformed, and can be used as a filler for light-colored rubber;
9. Lower ratio of heavy metals contained in the most advanced zinc oxide in France. The content of the metal is extremely low, so it does not affect the talent of the finished product, and does not cause pigmentation stains, and has the least influence on the pure whiteness of the finished rubber product;
10. Transparent or translucent and extremely low-zinc rubber products are extremely suitable;
11. Ultrafine particles are easily dispersed in rubber, and the amount is less than ordinary zinc oxide;
12. It can be used as an anti-softener in a large amount to make the rubber compound not easy to be deformed, and can be used as a filler for light-colored rubber;
13. The tear resistance, tensile coefficient and wear resistance of the finished rubber product are improved;
14. The scope of sulfurization is widened, the amount of sulfur is insufficient, and the risk of excessive sulfur addition can be greatly reduced;
15. The heavy metal content meets the strict standards of feed additives and is of high quality;
16. The active zinc oxide is characterized by a smaller particle size than the general zinc oxide, a lower content of impurities, and a larger relative surface area;
17. Additives for rubber, EVA foam and feed mineral additives.
Zinc oxide storage packaging
a. Store in a cool, ventilated warehouse.
b. Keep away from fire and heat.
c. It should be stored separately from the oxidant, avoid mixing.
d. The storage area should be provided with suitable materials to contain spills.
e. Lightly load and unload during handling to prevent damage and damage to the equipment.
f. Empty containers may contain harmful substances.
g. Closed operation, local exhaust.
h. Operators must be specially trained to strictly follow the operating procedures.
i. It is recommended that operators wear self-priming filter dust masks, chemical safety glasses, anti-poisoning work clothes, and latex gloves.
j. Avoid generating dust.
t. Avoid contact with oxidizing agents.
Method for preparing zinc oxide
At present, the production methods of zinc oxide in the world can be roughly divided into two categories: "fire method" and "wet method".
The "wet method", also known as the chemical method, is a method of producing zinc oxide which has arisen in recent years. There are many types of this law, but most of them are in the development stage. At present, the widely used method is sulfuric acid method, that is, crude ZnO is leached, deodorized and purified by sulfuric acid, and sodium carbonate is added for metathesis reaction, and the intermediate product is dried or calcined to obtain basic zinc carbonate or zinc oxide. As an improvement of the sulfuric acid process, ammonium hydrogencarbonate is also used instead of sodium carbonate as a precipitant. The advantage of this method is that a process can obtain a variety of products, the product quality is good, the disadvantage is that sulfuric acid and sodium carbonate (ammonium bicarbonate) consumption is large, the product cost is high, the equipment is seriously corroded, and the by-product sodium sulfate or ammonium sulfate is difficult to recover; If it is not recycled, direct discharge will cause environmental pollution.
The "fire law" is divided into two types: indirect law and direct law.
The indirect method, also known as the French method, is based on high-purity zinc ingots, which are sublimed at high temperature and oxidized to obtain zinc oxide. The advantage of this method is that the product has high purity. The disadvantage is that the zinc ingot is expensive, the energy consumption is high, the cost is high, the product activity is low, and the use surface is limited.
The direct method, also known as the US method, uses ore as a raw material to obtain zinc oxide products directly by high temperature reduction and oxidation. Although the method can use ore as raw material, the disadvantage is that the energy consumption is large, the product quality is unstable, and the first-class product rate is very low.