Electrolytic copper
A thick plate of crude copper (99% copper content) is prefabricated as the anode, a thin sheet of pure copper is made as the cathode, and a mixture of sulfuric acid and copper sulfate is used as the electrolyte. After being energized, copper dissolves into copper ions (Cu) from the anode and moves to the cathode, where it gains electrons and precipitates pure copper (also called electrolytic copper). Impurities in crude copper such as iron and zinc, which are more active than copper, are dissolved into ions (Zn and Fe) along with copper. Since these ions are not easily precipitated compared to copper ions, electrolysis can be avoided by adjusting the potential difference to avoid precipitation of these ions at the cathode. Impurities that are less reactive than copper, such as gold and silver, are deposited at the bottom of the electrolytic cell. The copper sheet produced in this way is called “electrolytic copper” and is of such high quality that it can be used to make electrical products.
Properties of copper:
Copper in the periodic table, the atomic number of 29, belongs to the first subgroup. Its properties are: ① physical properties of copper is a rose-red metal, soft, metallic luster, density of 8.92 g / cm3, the melting point of 1083.5 ℃, the boiling point of 2595 ℃, rich in ductility, easy to bend, good strength, in terms of electrical and thermal conductivity, copper is second only to silver, it can be hot and cold pressure processing, because of its face-centered cubic lattice, copper and its compounds Non-magnetic. The vapor pressure of copper at the melting point is very small, and thus not easily volatile at the temperature of the metallurgical process. ② chemical properties of liquid copper can dissolve certain gases, H2, O2, SO2, CO2, CO and water vapor, etc., dissolved gases have a certain impact on the mechanical properties of copper and electrical conductivity, pure copper at room temperature and dry air and wet air does not work, but in the CO2 wet air, the surface will produce a green film CuCO3Cu (OH) 2 also known as copper green, which ensures that copper is no longer corroded. Copper in the air heated to 185 ℃ that is the beginning of the role of oxygen, the surface to produce a layer of dark red copper oxide, when the temperature is higher than 350 ℃, copper color gradually from rose to brass, and finally become black. Copper can be dissolved in nitric acid and sulfuric acid with the presence of oxidizing agents, copper can be dissolved in ammonia, but also with oxygen, halogen and other elements directly combined.
Uses of electrolytic copper:
Electrolytic copper is a non-ferrous metal with very close relationship with human beings, is widely used in electrical, light industry, machinery manufacturing, construction industry, national defense industry and other fields, second only to aluminum in the consumption of non-ferrous metal materials in China. Copper is the most widely used in the electrical and electronic industry, the largest amount, accounting for more than half of the total consumption. It is used in various cables and wires, winding resistances of motors and transformers, switches and printed circuit boards. In the manufacture of machinery and transport vehicles, it is used in the manufacture of industrial valves and fittings, instruments, sliding bearings, molds, heat exchangers and pumps. In the chemical industry widely used in the manufacture of vacuums, distillation pots, brewing pots, etc. In the defense industry, it is used to make bullets, shells, gun parts, etc. For every 1 million rounds of bullets produced, 13 – 14 tons of copper are needed. In the construction industry, it is used to make various pipes, pipe fittings, decorative devices, etc.
