Smelting and Roasting of Copper Concentrates
Throughout the world, copper ore is mined, processed and smelted to produce copper and copper products. Copper concentrates are copper ore that have been processed and then concentrated to remove unwanted materials such as silicates and sulfur. To produce a final product for more direct use, the copper concentrates must be smelted and roasted.
Smelting is the process by which copper concentrates are heated and then mixed with a flux material that separates the ore from its impurities. During this high-temperature process, called fluxing, the flux material removes impurities including sulfur, arsenic, lead, zinc and other elements. The impurities are removed as vapor and gas products while the molten copper is poured into iron-silicate molds to cool. Following smelting, the impure molten iron silicate is washed away and the molten copper that is left then undergoes further processing.
During the roasting process, the copper concentrate is heated to temperatures between 700 and 1200 degrees Celsius in a furnace, or oven. At this temperature, water and other volatile components, like sulfur and chlorine, are removed. Further, the sulfates are converted to oxides as a result of the oxidation process. The roasting process also helps to prepare the copper for further smelting.
When copper concentrates are roasted and smelted to remove the impurities, the resulting copper is far more pure than when the copper was first mined. In fact, copper can reach up to 99% purity after the smelting and roasting process is complete. The high purity of copper is essential for its use in electrical applications, such as wiring and motor construction.
The roasting and smelting process of copper concentrates can be a difficult and expensive process to undertake. The equipment used for this is not cheap, and the necessary precise temperature and control over the furnace can be difficult achieve. In addition, the emissions to the air must be carefully monitored and kept in check to protect the environment. Despite the technical difficulty, however, the process of smelting and roasting copper is essential for the production of final copper products that are necessary for our modern way of life.
