Views: 1 Author: Site Editor Publish Time: 2022-09-13 Origin: Site
Zinc is a chemical element. The chemical symbol is Zn, atomic number is 30, in the periodic table of chemical elements in the fourth period, ⅱB group. Zinc, a silver-white metal with a bluish tinge, is the fourth most common metal.
1. The density is 7.14g/cubic centimeter, and the melting point is 419.5℃. The relative atomic weight is 65.409.
2. Zinc is brittle at room temperature; 100 ~ 150℃, soft; Above 200℃, it dries again.
3. The chemical properties of zinc are active. In the air at room temperature, a thin and dense basic zinc carbonate film is generated on the surface, which can prevent further oxidation. When the temperature reaches 225℃, the zinc oxidizes violently.
4. Zinc is difficult to burn in air and emits strong white light in oxygen.
5. zinc surface has a layer of zinc oxide, white smoke when burning, the main component of white smoke is zinc oxide, not only blocking zinc combustion, will refract the flame color to form a pale light.
6. zinc is easily soluble in acid, but also easy to replace gold, silver, copper and so on from the solution.
7. elemental zinc, can react with acid, and can react with alkali. Zinc oxide and zinc hydroxide are soluble in both acids and alkalis.
Zinc is an important raw material of non-ferrous metals. At present, zinc is the third largest non-ferrous metal in the consumption of non-ferrous metals, second only to copper and aluminum. Zinc metal has good ductility, wear resistance and corrosion resistance, and can be made with a variety of metals into alloys with better physical and chemical properties. The main products produced by primary zinc enterprises are: zinc metal, zinc base alloy, zinc oxide, these products are very widely used, mainly in the following aspects:
1. Galvanized. Used as ANTICORROSIVE COATING (such as galvanized sheet), widely used in automobile, construction, shipbuilding, light industry and other industries, accounting for about 46% of the amount of zinc.
Zinc has excellent atmospheric corrosion resistance, so zinc is mainly used in steel and steel structural parts of the surface coating. Electroplating with hot dip galvanized alloy surface oxidation will form a layer of uniform and fine basic zinc carbonate ZnCO3o3Zn (OH) 2 oxide film protective layer, the oxide film protective layer and prevent mold growth. Because zinc alloy plate has good atmospheric corrosion resistance, in recent years Western countries also began to try to directly use it to do roof cover material, with it to do roof plate service life can be as long as 120-140 years, and can be recycled and reused, and galvanized iron plate roofing material service life is generally 5-10 years.
2. Manufacture copper alloys (e.g. Brass). Used in automobile manufacturing and machinery industries, accounting for about 15% of zinc consumption. Zinc has suitable mechanical properties. Strength and hardness of the zinc itself is not high, after joining the alloy element such as aluminum, copper, its strength and hardness are greatly improved, especially the appearance of zinc and copper titanium alloy, the comprehensive mechanical performance is close to or reach the level of the aluminum alloy, brass, gray cast iron, the creep performance is greatly improved, therefore, zinc and copper titanium alloy has been widely used in hardware production.
Zinc is fused with copper to form brass, which is the traditional use of zinc. Brass is considered a highly functional alloy and can be molded by all traditional methods, such as casting, rolling, extrusion forging and hot pressing.
3. Used for casting zinc alloy. Mainly for die casting, used in automobile, light industry and other industries, accounting for about 15% of zinc consumption. The machining properties of many zinc alloys are relatively good, and the processing rate can reach 60%-80%. Excellent medium pressure performance, can carry on deep drawing, and has self-lubricity, prolong the life of the mold, can be brazed or resistance welding or arc welding (in helium gas) welding, surface can be electroplated, paint treatment, cutting performance is good, under certain conditions has superior superplastic energy.
In addition, zinc has good resistance to electromagnetic field. The conductivity OF zinc is 29% of that of standard electrical copper, and it is a very effective shielding material in the case of radio frequency interference. At the same time, because zinc is non-magnetic, it is suitable to be used as material for instrument parts, instrument shells and coins. In addition, zinc itself and other metal collision will not spark, suitable for underground explosion-proof equipment.
4. Used in the manufacture of zinc oxide. Widely used in rubber, coating, enamel, medicine, printing, fiber and other industries, accounting for about 11% of the amount of zinc.
5. Used in the manufacture of dry batteries, in the form of zinc cake, zinc plate, accounting for about 13% of zinc consumption.
Zinc has suitable chemical properties. Zinc can interact with NH4CI to release H+ ions. Zinc-mno2 battery makes use of this characteristic of zinc. It uses zinc alloy as the shell of the battery, which is not only the container of electrolyte, but also the anode of the battery. In addition, its performance is also widely used in the pharmaceutical industry.