Problem description:
What is the difference between copper ore and copper concentrate and its main distribution in the world?
Analysis:
Copper is the earliest metal used by human beings. As early as prehistoric times, people began to mine open-pit copper mines and use the obtained copper to make weapons, tools and other utensils. The use of copper had a far-reaching impact on the progress of early human civilization. Copper is a metal that exists in the earth's crust and ocean. The copper content in the crust is about 0.0 1%, and in some copper deposits, the copper content can reach 3-5%. Most of the copper in nature exists in the form of compounds, that is, copper ores. Copper minerals and other minerals are polymerized into copper ore, and the mined copper ore is processed into high-grade copper concentrate.
I. Performance
Copper has good physical and chemical properties, such as electrical conductivity, thermal conductivity, corrosion resistance and ductility. Electrical conductivity and thermal conductivity are second only to silver. Pure copper can be drawn into thin copper wire and made into thin copper foil. The fresh section of pure copper is rose red, but after the copper oxide film is formed on the surface, its appearance is purple red, so it is often called red copper.
Besides pure copper, copper can also be metallized with tin, zinc and nickel to form alloys with different characteristics, namely bronze, brass and white copper. Adding zinc to pure copper (99.99%) is called brass. For example, the condensers of power plants and radiators of automobiles all use ordinary brass tubes containing 80% copper and 20% zinc. Nickel is called white copper, and the rest is called bronze. Except for zinc and nickel, copper alloys of other metal elements are called bronze, and what elements are added is called what elements. The most important bronzes are tin phosphor bronze and beryllium bronze. For example, tin bronze has a long history of application in China, and it is used to cast bells, ding, musical instruments and ritual vessels. Tin bronze can also be used as bearings, bushings and wear-resistant parts.
The conductivity of copper is different from that of pure copper. With the help of alloying, the strength and corrosion resistance of copper can be greatly improved. Some of these alloys have good wear resistance and castability, while others have good mechanical properties and corrosion resistance.
Second, the use
Copper is widely used in industry because of its excellent properties. Including electrical industry, machinery manufacturing, transportation, construction, etc. At present, copper is mainly used to manufacture wires, communication cables, motors, generator rotors, electronic instruments and meters in the electrical and electronic industry, accounting for about half of the total industrial demand. Copper and copper alloys play an important role in computer chips, integrated circuits, transistors, printed circuit boards and other equipment and devices. For example, Cr-Zr-Cu alloy with high electrical conductivity and high thermal conductivity is used for transistor leads. Recently, IBM, an internationally renowned computer company, used copper instead of aluminum in silicon wafers, which marked the latest breakthrough in the application of the oldest metal in semiconductor technology.
In the mid-1980s, the electrical industry accounted for the largest proportion of refined copper consumption in the United States, Japan and Western European countries, and China was no exception. After the 1990s, copper used in pipelines abroad increased sharply, becoming the bulk of copper consumption abroad. According to the report released by new york Copper Development Association (CDA), from 65438 to 0997, the construction industry is still the largest end-use market of copper products in the United States. The corrosion resistance of copper is often used by the construction industry to manufacture water supply and drainage facilities such as water pipes and roofs. In addition, because of its beautiful appearance, it is also used for architectural decoration and construction.
According to the internal statistics of China Nonferrous Metals Group, from 65438 to 0997, the electrical industry (including wires and cables) accounted for 77.7% of China's copper consumption, making it the largest market for copper.
Details are as follows:
Unit:%
Mid-1980s 1997
The United States, Japan, Western Europe, China and the United States * China.
Electrical industry 47.8 55.2 24.8 77.7
Mechanical manufacturing19.5 23.811.5 5.3
Construction industry 15.8 3.3 4 1.8 6.9
Transportation 8.8 3.3 12.8 4.4
Other 8.1.14.49.1.5.7
Total100100100100.
Source: Dictionary of Futures Trading * Copper Development Association
note:
1997 China copper consumption structure data comes from Simon Hunter's article "China copper consumption survey report". In order to avoid double counting, the wires and cables of China 1990- 1997 are classified as electrical industry, whereas they were previously classified as mechanical manufacturing.
With the rapid development of science and technology, the application of copper is more and more extensive, and copper has begun to play a role in medicine, biology, superconductivity, environment and so on. For example, when polyurethane plastic foam contains copper or copper oxide, it can greatly reduce the deadly toxic gas-hydrocyanide (HCN) released when this plastic burns. A large number of research data prove that the bactericidal effect of copper can effectively reduce the spread of pneumonia bacteria, inhibit the growth of bacteria and keep drinking water clean and hygienic. Therefore, the future development prospect of copper tube in domestic construction industry will be very broad.
Three, copper reserves:
There are abundant copper resources in the world. According to the statistics of US Bureau of Mines 1995, the world copper reserves are 31000000 tons, with a reserve base of 590 million tons. The countries with the largest copper reserves are Chile and the United States, accounting for 23.7% and 15.3% of the world reserve base respectively, followed by Poland 15%, Zambia 6%, Russia 5% and Russia 5%.
The industrial types of copper mines in the world are divided into nine types: porphyry type, sandstone shale type, copper-nickel sulfide type, pyrite type, copper-uranium-gold type, native copper type, vein type, carbonate type and skarn type. The first four categories are the most important, accounting for 96% of the world's total copper reserves, of which porphyry and sandstone-shale minerals account for 55% and 29% respectively. There are about 60 giant copper mines with copper reserves exceeding 5 million tons in the world, including 38 porphyries and 0/5 sandstone/kloc, accounting for 88% of the giant copper mines.
There are few copper concentrate resources available for mining in China. At present, the main copper mines are Dexing copper mine in Jiangxi, Yulong copper mine, Yulong copper mine and Ashele copper mine newly discovered in Xinjiang.
Fourth, copper smelting process
Copper ore mined from copper mines is processed into copper concentrate or copper ore with high copper grade, and copper concentrate needs smelting commission to become refined copper and copper products.
At present, there are two main ways of copper smelting in the world: pyrometallurgical smelting and wet smelting (SX-EX).
1. Fire method:
Cathode copper, electrolytic copper, is produced by smelting and electrolytic refining, and is generally suitable for high-grade copper sulfide ores.
In addition to copper concentrate, waste copper is one of the main raw materials for copper smelting, including old waste copper and new waste copper. Old copper scrap comes from old equipment and machines, abandoned buildings and underground pipelines. The new scrap copper comes from the scrap copper abandoned by the processing plant (the proportion of copper production is about 50%), and the supply of scrap copper is generally stable. Waste copper is divided into: bare copper: the grade is above 90%; Scrap copper (wires): copper-containing materials (old motors, circuit boards); Copper produced from waste copper and other similar materials is also called recycled copper.
2. Wet method:
A ship is suitable for low-grade copper oxide, and the refined copper produced is called electrodeposited copper.
3. Characteristics of pyrometallurgy and hydrometallurgy
Compared with pyrometallurgy and wet copper production process, it has the following characteristics:
(1) The smelting equipment of the latter is simpler, but the impurity content is higher, which is a beneficial supplement to the former.
(2) The latter is limited by the grade and type of ore.
(3) The cost of the former is about 70-80 cents/pound (about 1540- 1760 USD/ton), while the latter is only 30-40 cents/pound (about 660-880 USD/ton).
It can be seen that wet smelting technology has considerable advantages, but its application scope is limited, and not all copper mines can adopt this technology. However, through technical improvement, in recent years, more and more countries, including the United States, Chile, Canada, Australia, Mexico and Peru, have applied this process to more copper smelting. The improvement of hydrometallurgy technology and the popularization of its application have reduced the production cost of copper, improved the productivity of copper mines, and increased the supply of social resources in a short time, resulting in a relative surplus of total social supply, which has a pulling effect on prices. 1997 copper futures price dropped from the high of $2,600/ton in196 to about $0/1600/ton at present, which is directly related to the large increase in the proportion of hydrometallurgical processes, resulting in a large number of low-priced copper listed.
At present, because the average production cost of copper is 1, 400- 1, 600 USD/ton (64-73 cents/pound), the decline of futures price is a reasonable return of price to value. With the increasing proportion of copper in smelting process, the price trend of copper will be more and more profound. It is reported that the current cost of copper hydrometallurgy is only 20 cents/pound (US$ 450/ton), the highest is 77 cents/pound (US$ 65,438+US$ 0,697.5/ton), and the average is about 50 cents/pound (US$ 65,438+US$ 0,654,38+US$ 0,000) It should be pointed out that in 1995, the average production cost of copper hydrometallurgy was only 39 cents/pound. Recently, the average production cost of copper hydrometallurgy has increased, mainly because the copper hydrometallurgy process has been extended to treat copper sulfide minerals. The copper hydrometallurgy process is more suitable for treating oxidized minerals and poor minerals of copper, while the production cost of the copper hydrometallurgy process is higher than 50 cents/pound when treating sulfide minerals and rich minerals, or when the mine is located in cold areas.
China began to study the technology of extracting copper from low-grade copper ore in 1970s. 1983, the first copper hydrometallurgy plant was established, with an annual output of 120 tons. Recently, due to the introduction of foreign excellent copper extractant and the development of local copper industry, dozens of small hydrometallurgical plants have been built, ranging from several hundred tons to 2,000 tons, but the annual output of copper is only 1.5. At present, the production cost of copper in China is about 18500 yuan, which is much higher than the world average of 1477 US dollars (67 cents). During the Ninth Five-Year Plan period, the State Planning Commission and China Nonferrous Metals Industry Corporation listed hydrometallurgy projects as key research projects, and built several demonstration plants in Dexing Copper Mine, Yulong Copper Mine and Daye Tonglushan Copper Mine. After several years' efforts, it is predicted that by the end of this century, China's hydrometallurgy technology will develop greatly and its annual production capacity will reach more than 50,000 tons.
According to statistics, the refined copper production of copper hydrometallurgy accounted for 2.5% of the world refined copper production in 1980, and this proportion increased to 10% in 1997. It is expected that the proportion of copper produced by hydrometallurgy will increase to 25-35% in the end.
Unit: ten thousand tons
1980 1994 1997 1998
The specific gravity of copper hydrometallurgy is 2.5% 10% 18% 20-25%.
The output of wet copper is 24 108 172.3 225.