Copper production has an important subproduct: molybdenum. It is a metallic element used as raw material for special steels and other alloys to which it gives its properties: resistance to temperature and corrosion, durability and strength.

Molybdenum does not exist pure en nature but it is always associated to other elements, such as the sulfide ores from which copper is also obtained.

In the Periodic Table of Elements, molybdenum is number 42 and is symbol is Mo. It melts at a temperature of 2,610 degrees Celsius.

Its name comes from the greek "molybdos" which means "similar to lead" in reference to is dark grey aspect. Although it is thought that some of its properties were known in antiquity, the elements was identified in the late XVIII century.

Only after a century its advantages for steel alloying came to be known. During the First World War, when the demand for tungsten almost exhausted the supply, this metal was replaced by molybdenum and this started its commercial exploitation.

Molybdenum is mainly used to manufacture more resistant steels, but it is also employed as component of superalloys, of nickel alloys and the lubricant, chemical and electronic industry.

The largest molybdenum reserves are in the United States, followed by Chile. Codelco is one of the main companires producing this element in the world, with some 24,000 metric tons a year.

Codelco is part of the INternational Molybdenum Association (http://www.imoa.info/), the international organization that promotes molybdenum use.