Introduction to the basic knowledge of copper

1. Natural attributes
Copper is one of the earliest ancient metals discovered by mankind. Mankind began to use copper more than 3,000 years ago.

Metal copper, element symbol Cu, atomic weight 63.54, specific gravity 8.92, melting point 1083oC. The pure copper is light rose or light red, and after a copper oxide film is formed on the surface, the appearance is copper-colored. Copper has many valuable physical and chemical properties, such as high thermal and electrical conductivity, strong chemical stability, high tensile strength, easy welding, corrosion resistance, plasticity, and ductility. Pure copper can be drawn into very thin copper wires and made into very thin copper foil. It can form alloys with zinc, tin, lead, manganese, cobalt, nickel, aluminum, iron and other metals.

The development of copper smelting technology has gone through a long process, but so far copper smelting is still dominated by fire smelting, and its output accounts for about 85% of the world’s total copper output. 1) Pyrometallurgy is generally to first increase the raw ore containing a few percent or a few thousandths of copper to 20-30% through beneficiation, and use it as a copper concentrate in a closed blast furnace, reverberatory furnace, electric furnace or flash furnace For matte smelting, the produced matte (copper matte) is then sent to a converter for blowing into blister copper, and then oxidized and refined in another reverberatory furnace to remove impurities, or cast into an anode plate for electrolysis to obtain a high grade 99.9% electrolytic copper. The process is short and adaptable, and the recovery rate of copper can reach 95%. However, because the sulfur in the ore is discharged as sulfur dioxide waste gas in the two stages of matte production and conversion, it is difficult to recover and easy to cause pollution. In recent years, molten pool smelting such as the silver method and the Noranda method, as well as the Mitsubishi method in Japan, has gradually developed towards continuous and automated pyrometallurgy. 2) Modern wet smelting includes sulfuration roasting-leaching-electrodeposition, leaching-extraction-electrodeposition, bacterial leaching, etc., suitable for heap leaching and tank leaching of low-grade complex ore, copper oxide ore, copper-bearing waste ore Or leaching in place. The hydrometallurgical technology is gradually being promoted, and it is expected that it will reach 20% of the total output by the end of this century. The introduction of hydrometallurgy has greatly reduced the cost of copper smelting.

2. Classification of copper and copper products

1. Classification according to the existing forms in nature

Natural copper-the copper content is above 99%, but the reserves are very small;

Copper oxide ore—–not many

Copper sulfide ore-the copper content is extremely low, generally around 2-3%. More than 80% of the world’s copper is refined from copper sulfide ore.

2. Classified by production process

Copper concentrate-ore with higher copper content selected before smelting.

Blister copper-the smelted product of copper concentrate, with a copper content of 95-98%.

Pure copper-copper with a content of more than 99% after smelting or electrolysis. Fire refining can obtain 99-99.9% pure copper, and electrolysis can make the purity of copper reach 99.95-99.99%.

3. Classified by main alloy composition

Brass—–copper-zinc alloy

Bronze—–copper-tin alloy, etc. (except for zinc-nickel, alloys with other elements are called bronze)

Cupronickel—–copper-cobalt-nickel alloy

4. Classified by product form: copper tube, copper rod, copper wire, copper plate, copper strip, copper strip, copper foil, etc.

3. Copper product number and quality standard

The quality standard for the subject matter of the copper futures contract before September 1997 was the GB466-82 standard, and the delivery product was No. 1 copper. From September 1997 to August 1998, GB466-82 and GB/T-467-1997 were both The standards are implemented at the same time. Since September 1998, all GB/T467-1997 standards have been implemented. Both high-purity copper cathodes and standard copper cathodes can be delivered. There is no quality premium or discount, only brand premiums and discounts.

1. The chemical composition of high-purity cathode copper (Cu-CATH-1): Cu+Ag is not less than 99.95, and the total impurity content does not exceed 0.0065 (the impurity classification content is omitted).

Copper is a widely used metal with unique advantages in terms of conductivity, conductivity, tensile strength, extensibility, corrosion resistance, and fatigue resistance. It is mainly used in industrial equipment manufacturing, electrical Industry, communication industry, construction industry, transportation industry, fastener industry, etc. The numerous uses also make the price of copper very sensitive to changes in supply and demand and fluctuates widely. The close correlation between copper and social life makes copper demand directly related to changes in economic conditions.

In addition to mining, the supply of copper can also be obtained through secondary recovery. The main copper producing countries in the world are Chile, the United States, Canada, Zambia, Zaire and Peru. my country is also a major copper producer, and its output in 1991 ranked seventh in the world. my country’s copper production is mainly concentrated in Jiangxi, Xiangbei, Gansu, Tianjin, Shanghai, Anhui, Liaoning, Shanxi, Hunan, and Yunnan. However, due to the low grade of my country’s copper ore, unsatisfactory resource conditions, and a large demand for copper, copper and copper alloys are imported every year to meet the shortage of supply.

In 2001, the global consumption of copper was about 14.885 million tons, and copper consumption was concentrated in developed industrial countries. The United States is the largest copper consumer. In 2000, it consumed 2.923 million tons, accounting for about one-fifth of the world’s total consumption, followed by China 1.75 million tons, Japan 1.327 million tons, and Europe 4.385 million tons. From an industry perspective, the electrical industry and the construction industry consume the most copper.

In 2002, the world’s refined copper production was 15.02 million tons, consumption was 14.90 million tons, and the supply and demand gap was 120,000 tons. The balance of supply and demand in 2001 was an oversupply of 948,000 tons, and the contradiction between supply and demand has been greatly improved.