1. Introduction to zinc Zinc, chemical symbol Zn, atomic number 30, is a transition metal. Zinc is widely distributed in nature and is one of the essential trace elements in living organisms. It is widely used in industrial production, construction, transportation, medicine and other fields. The name zinc comes from the Latin “zinco”, which means “tin-like metal” because in ancient times, zinc was often confused with tin.
2. Physical properties of zinc Color and luster: Pure zinc is silvery white with metallic luster. In the air, the zinc surface will gradually oxidize, forming a gray-white zinc oxide film. Density and melting point: The density of zinc is about 7.14g/cm³, the melting point is 419.5℃, and the boiling point is 907℃. This makes zinc have good processing properties at room temperature and is suitable for various manufacturing processes. Ductility and conductivity: Zinc has certain ductility and conductivity and can be drawn into filaments or pressed into sheets, but its electrical and thermal conductivity are not as good as those of copper and aluminum. Hardness and strength: Pure zinc has a low hardness, but its hardness and strength can be increased through alloying to meet the needs of different fields.
3. Chemical properties of zinc react with oxygen: Zinc can react with oxygen in the air to form zinc oxide. 2Zn + O₂ = 2ZnO reacts with acids: Zinc can react with non-oxidizing acids such as dilute sulfuric acid and dilute hydrochloric acid to generate corresponding zinc salts and hydrogen. Zn + H₂SO₄ = ZnSO₄ + H₂↑
Zn + 2HCl = ZnCl₂ + H₂↑Reaction with alkali: Zinc can react with strong alkali solution to generate zinc hydroxide and hydrogen gas. Zn + 2NaOH = Na₂ZnO₂ + H₂↑Reaction with salt solution: Zinc can undergo displacement reaction with some soluble salt solutions, such as copper salt solution, silver salt solution, etc. Zn + CuSO₄ = ZnSO₄ + Cu
Zn + 2AgNO₃ = Zn(NO₃)₂ + 2Ag
4. Existence form and extraction of zinc (1) Existence form Sphalerite: Zinc mainly exists in sphalerite. The main component of sphalerite is zinc sulfide (ZnS), which usually also contains other elements such as iron and lead. Other minerals: Zinc also exists in some other minerals, such as smithsonite (main component is ZnCO₃), hemimorphite (main component is Zn₄Si₂O₇(OH)₂·H₂O), etc. (2) Extraction process and mineral processing: After the ore mined from the mine undergoes crushing, screening, grading and other processes, the ore with higher zinc content is selected. Roasting: The selected ore is roasted to improve the reducibility and grade of the ore. Smelting: Use pyrometallurgy or hydrometallurgy to convert zinc sulfide into metallic zinc. Pyrometallurgy mainly includes steps such as distillation and reduction; hydrometallurgy mainly uses chemical reagents to dissolve zinc from the ore. 2ZnS + 3O₂ = 2ZnO + 2SO₂↑
ZnO + C = Zn + CO↑
5. Applications of zinc (1) Application of galvanizing in daily life: Zinc has good corrosion resistance, so it is often used for galvanizing treatment on metal surfaces to improve the corrosion resistance of metals. For example, galvanized iron sheet, galvanized steel pipe, etc. Battery: Zinc plays an important role in battery manufacturing. For example, dry batteries, storage batteries, etc. all use zinc as the negative electrode material. Alloy materials: Zinc alloy has good casting properties and mechanical properties and is widely used in the manufacture of various parts and decorations. (2) Application in industrial production Steel smelting: Zinc is used as a deoxidizer and desulfurizer in the steel smelting process, which can improve the quality and performance of steel. Chemical industry: Zinc is widely used in the chemical industry, such as in the manufacture of pigments, dyes, catalysts, etc. Medical field: Zinc is one of the essential trace elements for the human body and has a variety of physiological functions, such as participating in the regulation of enzyme activity and enhancing immune function. Therefore, zinc is also widely used in the medical field, such as treating zinc deficiency and enhancing immunity.
Post time: Nov-06-2024
