Copper

What is Copper?

Copper is one of the most important metals. It is less reactive and very resistant to corrosionCorrosion is defined as a natural process that causes the transformation of pure metals into undesirable substances when they react with substances like water or air. This reaction causes damage and... More. Along with silver, and gold, copper is also a noble metal. One of the most important ores of copper is copper pyrites, CuFeS₂. Copper also occurs as cuprite, Cu₂O, chalcocite, Cu₂S, malachite, CuCO₃.Cu(OH)₂ and bornite, Cu₂S.CuS.FeS.

Extraction of Copper 

Copper is usually extracted from copper pyrites, CuFeS₂. The ore is concentrated via froth floatation. It is then heated with silicate in the presence of air to oxidize the iron impurity to iron (I) oxide, Cu₂O, and sulphur to sulphur (IV) oxide SO₂.

2CuFeS₂ + 2SiO₂ + 4O₂  → Cu₂S + 2FeSiO₃ + 3SO₂

The copper (I) sulphide form is converted to copper by heating it with oxygen. The purity of copper obtained in such a manner is 97- 99% pure.

This crude copper is then subjected to electrolysis to get copper of 99.95% purity.

The copper is dissolved in tetraoxosulphate (VI) acid to obtain copper (II) tetraoxosulphate (VI) which becomes the electrolyteAn electrolyte is a substance that dissociates in water into charged particles called ions. Positively charged ions are called cations. Negatively charged ions are called anions. Simply, an electrolyte is a... More in the electrolytic cell. Impure copper is used as the anodeAn anode is an electrode of a polarized electrical device through which conventional current enters the device. It is the positive part of electrolytes where oxidation takes place. More while strips of highly pure copper are used as the cathodeA cathode is the electrode from which a conventional current leaves the electrolyte. It is the negative part of the cell where reduction takes place. More.

The electrolytic cell can be represented as below.

At the cathode: copper (II) ions are reduced and deposited as copper metal.

Cu²⁺_(aq) + 2e⁻  →  Cu_(s)

At the anode: copper goes into solution as copper (II) ions.

Cu_(s) → Cu²⁺ _(aq) + 2e⁻

Uses of Copper

i. Copper metal is used in making electrical wires. It is ductile and has the second-best electrical conductivity. It is used in nearly all electrical devices and wiring.

ii. Copper is resistant to corrosion and has an attractive look. It is used in construction and roofing. Bronze and brass, are alloys of copper commonly used in construction. Copper is also used in plumbing works. Copper is also used in making cooking utensils.

iii. Copper is used in making different alloys. These alloys are used for several purposes. Bronze is an alloy containing copper and tin. Brass is an alloy of copper that contains copper and nickel.

iv. Copper is also used in the electroplating of metals.