1, which is made 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.

It is obtained by oxidation of molten zinc.

5. There are three methods: indirect method with zinc ingot as raw material (also called French method), direct method with zinc ore as raw material (also called American method) and wet method.

Second, the indirect method. Reaction equation: 2Zn+O2=2ZnO.

Operation method: after the zinc ingot prepared by electrolysis is heated to 600-700℃ for melting, it is put into a high-temperature crucible, melted and gasified at the high temperature of 1250- 1300℃, and hot air is introduced for oxidation. After the generated zinc oxide is cooled, it is separated by a cyclone separator, and fine particles are captured by a cloth bag to obtain the finished zinc oxide.

Direct method. Reaction equation:

C+O2=CO2

Carbon dioxide+carbon = carbon dioxide

ZnO+CO=Zn (steam) +CO2

Zinc (steam)+carbon monoxide+oxygen = zinc oxide+carbon dioxide

Operation method: mix the roasted zinc powder (or zinc-containing materials), anthracite (or coke) and limestone into balls according to the ratio of 1: 0.5: 0.05. After reduction smelting at 1300℃, the zinc oxide in the mineral powder is reduced to zinc vapor, and then air is introduced for oxidation, and the generated zinc oxide is captured to prepare the finished zinc oxide product.

3. Wet method. Zinc powder reacts with sulfuric acid to produce zinc sulfate, and then reacts with sodium carbonate and ammonia water respectively to prepare zinc oxide from zinc carbonate and zinc hydroxide. The reaction equation is as follows:

Zinc+sulfuric acid = zinc sulfate +H2

znso 4+na2co 3 = znco 3←+na2so 4

znso 4+2 NH3·H2O = Zn(OH)2↓+(NH4)2so 4

Zinc oxide was prepared from zinc carbonate by washing, drying, calcining and crushing. Zinc carbonate → zinc oxide+carbon dioxide

Taking zinc hydroxide as raw material, the product zinc oxide was prepared through washing, precipitation, drying, calcination, cooling and crushing. Zinc hydroxide → zinc oxide +H2O