1. About copper

An essential element for life, copper is present in the earth's crust, oceans, lakes and rivers. Most mines have copper contents ranging from 0.2% to 0.8%, and some contain up to 6%. Generally, copper is found as sulfides such as chalcopyrite (CuFeS ₂ ), covelline or covellite (CuS), chalcosine or chalcocite (Cu ₂ S), oxides such as cuprite (Cu ₂ O) and even in its native state.

Along with gold, copper was the first metal to be worked by man: it was first used around 9,000 years ago. Today, it is one of the most widely used materials, and will continue to be so in the future, thanks to i) its intrinsic characteristics, which make it a reference material for a wide range of uses, and ii) its eco-compatibility: it can be recycled without...