Productive processes

The fact that copper is found dispersed in nature makes it necessary to submit the ores to processes to obtain the pure metal.

In the beginning of history, man found the metal in its natural state and applied it to different uses with simple techniques of heating and hammering.

Later on, the early metallurgical techniques made possible to work veins of high purity, from which minerals such as malachite (copper carbonate) could be obtained, which submitted to a process of melting produced nuggets of pure copper.

But as civilization advanced the mineral deposits with a high grade of copper were exhausted and the early metallurgical techniques had to be gradually replaced by new ones.

The great demand for copper that started with the Industrial Revolution encouraged the search for new technologies making possible to exploit the porphyric deposits of lower grades in which the ore is found disperse in large areas and mixed with other elements and rock.

Copper is mainly found associated to sulfide minerals, but also to oxide minerals.

These two types of minerals require different productive processes, but in both cases the starting point is the same: the extraction of the material from open pit or underground mines, which requires the fragmentation and transportation of the material that has been previously identified by geological surveys.

Codelco operates one of the largest open pit mines in the world, Chuquicamata, and also the largest underground mine, El Teniente.

The extracted mineral goes first through a milling process. In the case of oxide minerals, the processing involves submitting the material to a leaching solution, which will produce solutions of copper sulphate, which enter a process of solvent extraction followed by electrowinning, which final result is a copper cathode 99.99% pure.

The sulfide minerals go first through crushing and milling, followed by a classification process to obtain the copper concentrate, with 30% copper. Later purification stages are carried out in furnaces that generate blister or anode copper 99% pure. Finally, electrorefining transforms the anodes into 99.99% pure cathodes.