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Introduction and preparation method of zinc oxide

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Update time : 2021-08-06 09:27:35
Zinc oxide powder
Zinc oxide powder is an inorganic substance with a chemical formula of ZnO, which is an oxide of zinc. Hardly soluble in water, soluble in acid, and strong alkali. Zinc oxide powder is a commonly used chemical additive, which is widely used in the production of plastics, silicate products, synthetic rubber, lubricants, paints, ointments, adhesives, food, batteries, flame retardants, and other products. Zinc oxide powder has a large energy band gap and exciton binding energy, high transparency, and excellent room temperature light-emitting performance. It is used in liquid crystal displays, thin-film transistors, light-emitting diodes, and other products in the semiconductor field. In addition, micro-particle zinc oxide as a nanomaterial has also begun to play a role in related fields.
Physical properties of zinc oxide powder
Appearance and properties: white powder or hexagonal crystals. Odorless, tasteless, and non-sandy. It turns yellow when heated, and turns white again after cooling, and sublimates when heated to 1800°C. The hiding power is half that of titanium dioxide and zinc sulfide. The tinting strength is twice that of basic lead carbonate.
Solubility: soluble in acid, concentrated alkali hydroxide, ammonia and ammonium salt solution, insoluble in water and ethanol.
Chemical properties of zinc oxide powder
Zinc oxide powder is a famous white pigment, commonly known as zinc white. Its advantage is that it does not become black when it encounters H2S gas because ZnS is also white. When heated, ZnO gradually changes from white to light yellow to lemon yellow. When it cools, the yellow fades away. Using this feature, it can be mixed into paint or added to a thermometer to make a color-changing paint or a color-changing thermometer. Because ZnO has astringency and certain bactericidal ability, it is often used as an ointment in medicine. ZnO can also be used as a catalyst.


Preparation of zinc oxide powder
1. Direct method:
1. It is obtained by calcining zinc carbonate. ZnCO3=ZnO+CO2↑
2. It is obtained by calcining and decomposing zinc hydroxide.
3. Zinc is smelted from crude zinc oxide and then oxidized by high-temperature air.
4. Obtained from the oxidation of molten zinc.
5. The methods used include the indirect method (also called the French method) using zinc ingot as raw material, a direct method using zinc ore as raw material (also known as the American method), and the wet method.
2. Indirect method.
Reaction equation: 2Zn+O2=2ZnO
Operation method: After heating the zinc ingot made by electrolysis to 600700 to melt, place it in a high-temperature resistant crucible, make it melt and vaporize at a high temperature of 12501300, and introduce hot air to oxidize, and the zinc oxide produced is cooled, Cyclone separation, the fine particles are collected with a cloth bag, and then the finished product of zinc oxide is obtained.
Direct method. Reaction equation:
ZnO+CO=Zn (steam)+CO2
Zn (steam)+CO+O2=ZnO+CO2
Operation method: The roasted zinc ore powder (or zinc-containing material), anthracite (or coke), and limestone are made into balls at a ratio of 1:0.5:0.05. After reduction and smelting at 1300°C, the zinc oxide in the ore powder is reduced to zinc vapor, which is then oxidized by air, and the resulting zinc oxide is captured to obtain a finished product of zinc oxide.
3. Wet method.
Zinc ash is reacted with sulfuric acid to generate zinc sulfate, which is then reacted with sodium carbonate and ammonia water respectively to prepare zinc oxide using the obtained zinc carbonate and zinc hydroxide as raw materials. The reaction equation is as follows:
Using zinc carbonate as raw material, the product zinc oxide is obtained by washing, drying, calcining, and pulverizing. ZnCO3→ZnO+CO2↑
Using zinc hydroxide as raw material, the product zinc oxide is prepared by washing, precipitation, drying, calcination, cooling, and pulverization. Zn(OH)2→ZnO+H2O
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years’ experience in providing super high-quality chemicals and Nanomaterials. The Zinc oxide powder produced by our company has high purity, fine particle size and impurity content. Please contact us if necessary.
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