The development of copper metallurgy 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 copper output. The modern hydrometallurgical technology is gradually being promoted, and the introduction of hydrometallurgy The cost of copper smelting is greatly reduced. Let's take a closer look at the two copper smelting methods, fire smelting and wet smelting (SX-EX).
Fire copper smelting:
Cathode copper is produced by melting smelting and electrolytic refining, that is, electrolytic copper, which is generally suitable for high-grade copper sulfide ore. Pyro smelting generally involves first increasing the raw ore containing a few percent or a few thousandths of copper to 20-30% through beneficiation. As a copper concentrate, it is produced in a closed blast furnace, reverberatory furnace, electric furnace or flash furnace. After 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, with a grade of up to 99.9% Of 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. In addition to copper concentrates, copper scrap is also the main raw material for refined copper, including old scrap copper and new scrap copper. Old scrap copper comes from old equipment and machinery, abandoned buildings and underground pipelines; new copper scrap comes from processing plants discarded Copper scrap (the output ratio of copper materials is about 50%). Generally, the supply of copper scrap is relatively stable. Copper scrap can be divided into: bare copper (grade above 90%); yellow copper (wire); copper-containing materials (Old motors, circuit boards); copper produced from scrap copper and other similar materials, also called recycled copper.
Hydrometallurgy:
A ship is suitable for low-grade copper oxide, and the refined copper produced is electrowinning copper. Modern hydrometallurgy includes sulfuration roasting-leaching-electrowinning, leaching-extraction-electrowinning, bacterial leaching and other methods, suitable for low-grade complex ore, copper oxide ore, copper-containing waste ore heap leaching, tank leaching selection or selection地leaching. 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.
The process flow chart is as follows: Among them, the extraction of copper (the process that copper enters the organic layer from the water layer) and back extraction (the process that copper enters the water layer from the organic layer) are important process methods for modern copper hydrometallurgy.
The fire and wet processes have the following characteristics:
(1) The latter's smelting equipment is simpler, but the impurity content is higher, which is a beneficial supplement to the former.
(2) The latter has limitations and is subject to the grade and type of ore.
(3) The cost of the former is higher than the latter.
It can be seen that the hydrometallurgical technology has considerable advantages, but its scope of application is limited. Not all copper ore smelting can use this kind of technology. However, through technological improvements, more and more countries, including the United States, Chile, Canada, Australia, Mexico, and Peru, have applied the process to more copper smelting in recent years. The improvement of wet smelting technology and the promotion of its application have reduced the production cost of copper, increased the production capacity of copper mines, and increased the supply of social resources in the short term, resulting in a relative surplus of total social supply, which has a boosting effect on prices.
