The copper smelting technology has been developing for a very long time. But even today copper smelting shall still be smelted by fire, and its output accounts for 85% of the total cooper output of the world.
1.Generally pyrometallurgy raises the raw ore containing copper of several percent and parts per thousand by 20 to 30%. The copper concentrate shall undergo matte smelting in airtight blast furnace, reverberatory, electric furnace, or flash furnace. The generated molten matte (matte) shall then be sent into the converter and blown into crude copper, before being removed of impurities upon refining by oxidation in another type of reverberatory, or being cast into a positive plate for electrolysis. In this way, electrolytic copper with quality of 99.9% is obtained. This process is short and highly adaptable, with copper recovery rate of 95%. But because the sulphur in ores shall be discharged as sulfur dioxide waste gas during matte smelting and blowing, it is not easy to be recovered and is liable to cause pollution. In recent years, the silver method, Noranda process, and other bath smelting, as well as Mitsubishi method of Japan and so on have emerged. Now pyrometallurgy has become more and more continuous and automatic.
2.Modern wet smelting includes sulfating roasting- infusion- electrodeposition, infusion - extraction - electrodeposition, bacterial leaching and other methods. All these are applicable to the dump leaching, tank leaching selection or spot leaching of low-grade complex mine, copper oxide ore, and waste rock containing copper. The wet smelting technology has been popularized gradually, and is expected to come up to 20% of the total output at the end of this century. Hydrometallurgy has cut down the cost for smelting copper to a large extent.