I Natural Property

Copper is one of the ancient metals that are first to be discovered by humans. More than three thousand years ago, humans started their journey of copper usage.

Basic information of metal copper is as follows: Symbol: Cu; atomic weight: 63.54; specific gravity: 8.92; melting point: 1,083°C. Pure copper is in misty rose or light red. After a film of copper oxide is formed on the surface, the copper will be in aeneous. Copper has many valuable physical and chemical properties, like high thermal conductivity and electrical conductivity, strong chemical stability, high tensile strength, easiness to be welded, high corrosion stability, plasticity and malleability. Pure copper can be drawn into fine copper wire which can be used to produce extremely thin copper foil. In addition, copper can be used to make alloy with such metals as zinc, tin, lead, manganese, cobalt, nickel, aluminum and iron.

The copper smelting technology experiences a long development process, but up to now, pyrometallurgy is still the main process for copper smelting and copper output produced with pyrometallurgy accounts for about 85% of total output of the world. 1) Pyrometallurgy refers to enhance the original copper content of raw ore, a few percent or thousandths, to 20% ~ 30%, generate copper concentrates, conduct matte smelting in imperial smelting furnace, reverberatory furnace, electric furnace or flash furnace, send produced matte into a converter for blowing into crude copper, then send such crude copper into another kind of reverberatory furnace for oxidation, refining and purification or to cast into anode plate before electrolysis, and finally obtain cathode copper with copper content up to 99.9%. This flow is simple and highly adaptive, with recovery rate of copper up to 95%. But sulfur in ore is discharged as waste gas (sulfur dioxide) at two stages, matte smelting and blowing, so it is difficult to recover and easy to cause pollution. In recent years, such bath melting processes as copper smelting process with silver and Noranda's copper smelting process, Mitsubishi process from Japan have appeared. Pyrometallurgy tends to be continuous and automatic. 2) Modern pyrometallurgy has various methods: Sulfating roasting — leaching — electrodeposition, leaching — extraction — electrodeposition, bacterial leaching, etc. Such methods are applicable to dump leaching, tank leaching or spot leaching of low-grade complex ores, copper oxide ores and waste ores containing copper. Hydrometallurgy has been gradually promoted and it is estimated that copper output produced with hydrometallurgy can account for 20% of the total output of the world by the end of this century. Hydrometallurgy brings a sharp reduction in cost for copper smelting.

II Classification of Copper and Copper Products

1 Classification based on existing form in nature

Native copper ---- Having a copper content of over 99% but only found in small quantities;
Copper oxide ore ----- Also in small quantities;
Copper sulphide ore ----- Having a low copper content, generally 2% ~ 3%. More than 80% copper of the world is refined from copper sulphide ores.

2 Classification based on production process

Copper concentrate ---- Ores with a relatively high copper content selected before smelting.
Crude copper ---- Product produced after smelting of copper concentrate and having a copper content of 95% ~ 98%.
Pure copper ---- Copper with copper content exceeding 99% after pyro-refining or electrolysis. The copper content ranges from 99% to 99.9% through pyro-refining and from 99.95% to 99.99% through electrolysis.

3 Classification based on main content of alloy

Brass ---- Copper-zinc alloy
Bronze ---- Copper-tin alloy, etc.(bronze is an alloy consisting primarily of copper and commonly with other metals except zinc and nickel)
Cupronickel ----- Copper-cobalt-nickel alloy

4 Classification of product modality: Copper pipe, copper rod, copper wire, copper plate,  copper strip, copper bar, copper foil, etc.

III Article Number and Quality Standards of Copper

Before September 1997, the quality standard executed for futures contracts of the subject matter, copper, is Classification of Copper (GB466-82), with No. 1 copper as deliverables; from September 1997 to August 1998, the quality standards simultaneously executed were Classification of Copper (GB466-82) and Cathode Copper (GB/T-467-1997); after September 1998, the only effective quality standard executed is Cathode Copper GB/T-467-1997. Both high-purity cathode copper and standard cathode copper can be delivered, without any quality premiums or discounts but brand premiums and discounts.
1 Chemical composition of high-purity cathode copper (Cu-CATH-1): Cu+Ag: not less than 99.95; total content of impurities: not exceeding 0.0065 (content of each impurity is omitted)

IV Main Application of Copper

Copper, as a kind of nonferrous metal much close to human activities, has been widely used in such fields as electric industry, light industry, mechanical manufacturing, construction industry and national defense industry. In terms of consumption of non-ferrous metal materials, copper ranks only second to aluminum.
Copper is most widely used in electric industry and electronic industry with largest consumption, over half of the total consumption.