I. Natural Attributes Copper is one of the earliest discovered ancient humans. As early as 3,000 years ago, humans began to use copper.
Copper metal, symbol Cu, atomic weight 63.54, specific gravity 8.92, melting point 1083°C. Pure copper is light rose or light red, and the appearance of copper oxide film on the surface is copper color. Copper has many valuable physical and chemical characteristics, such as its high thermal conductivity and electrical conductivity, chemical stability, tensile strength, easy to weld, with corrosion resistance, plasticity, ductility. Pure copper can be drawn into very fine copper wire to make very thin copper foil. With zinc, tin, lead, manganese, cobalt, nickel, aluminum, iron and other metals to form alloys.
The development of copper smelting technology has undergone a long process, but so far the smelting of copper is still dominated by pyrometallurgical smelting, and its production accounts for about 85% of the world’s total copper production.
1) The pyrometallurgical smelting process is generally to increase the raw ore containing several hundredths or several thousandths of copper to 20-30% through beneficiation, as a copper concentrate, in a closed blast furnace, reverberatory furnace, electric furnace or flash furnace The combing smelting is performed, and the resulting comb (copper matte) is then sent to a converter for blowing into blister copper, and then is subjected to oxidation refining in another reverberatory furnace for decontamination, or is cast into an anode plate for electrolysis to obtain a grade as high as possible. 99.9% of electrolytic copper. The process is short and adaptable. The recovery rate of copper can reach 95%, but the sulfur in the ore is discharged as sulfur dioxide gas in the milling and blowing stages. It is not easy to recycle and can easily cause pollution. In recent years, molten smelting such as the silver method, Nolanda method, Japan's Mitsubishi method, etc., and pyrometallurgical smelting have gradually progressed to continuous and automated development.
2) modern wet smelting with sulphated roasting ---> leaching --> electrowinning, leaching --> extraction ---> electrowinning, bacterial leaching, etc., suitable for low-grade complexes, copper oxide ore , heap leaching of copper-containing waste ore, tank leaching, or leaching in situ. Wet smelting technology is being gradually promoted and is expected to reach 20% of the total production by the end of this century. The introduction of wet smelting greatly reduces the smelting cost of copper.
Second, copper and copper products
1, according to the existence of the natural classification
Natural copper-------- copper content is above 99%, but reserves are extremely low;
Oxidized copper ore ------ not many copper sulphide ore ------ copper content is extremely low, usually around 2 - 3%, more than 80% of the world's copper is refined from copper sulfide ore of.
2, classified by production process
Copper concentrate ------ The ore with higher copper content was selected before smelting.
Crude copper --- copper smelted products, copper content of 95-98%.
Pure copper-------- copper with a content of 99% or more after smelting or electrolysis. The pyrolysis results in 99-99.9% pure copper. Electrolysis can make the copper purity 99.95-99.99%.
3, according to the main alloy composition Brass ------- copper-zinc alloy bronze ------- copper-tin alloy (except for zinc and nickel, the addition of other elements of the alloy are called bronze)
4, by product morphology
Copper tubes, copper rods, copper wires, copper sheets, copper tapes, copper strips, copper foils, etc.