What is Copper? | Element data, Properties and Uses

 What is Copper?

Copper is a red-orange metallic luster, the copper symbol is Cu derived from the Latin word cuprum and the atomic number of copper is 29. The copper atomic weight is 63.54. It is located in d-block elements, the 11th group and 4th period of the periodic table. Its electronic configuration is [Ar] 3d10 4s1. There are 29 isotopes of copper among them 63Cu and 65Cu are stable, with 63Cu abundance is approximately 69%. Its oxidation states range from +1 to +4 of which Cu +1 (cuprous) and Cu +2 (cupric) are the most common oxidation states.

Occurrence

Copper is found in native and combined forms. The native copper is 99.9% pure but only minor sources of native copper are there. It's found in the USA, Mexico, Russia, and China. In combined form, copper found in

1. Oxide ores:

a) Cuprite.

b) Ruby copper.

2. Carbonate ores:

a) Malachite (green), CuCO3.Cu(OH)2 has 57% copper.

b) Azurite (blue), 2CuCO3.Cu(OH)2, has 65% copper.

3. Sulfide ores:

a) Chalcocite or copper glance; Cu2S has 80% copper.

b) Copper pyrites or chalcopyrites, CuFeS2 has 34% copper.

Out of these ores, the principal ore of copper is copper pyrite, which is mainly found in India, Bihar.

Extraction of copper from Oxide and carbonate ores:

The oxide ore is reduced by carbon to give metallic copper. The carbonate ore is crushed, concentrated by gravity process, and roasted. It decomposes to form the oxides and the impurities are volatilized. The oxide formed is reduced by carbon to get copper in a reverberatory furnace.

Extraction of copper from Sulphide ores:

Copper pyrites (CuFeS2) by Dry process:

This process is also called smelting or thermal process. The crushed ore is concentrated by the froth flotation process so that siliceous impurities are removed. The concentrated ore is then heated in the air in a reverberatory furnace. In this the following reaction takes place

1. Some sulfur, arsenic, and antimony are oxidized and removed.

2. CuFeS2 is converted into Cu2S and FeS mixture. 

3. Cu2S and FeS are partially oxidized to Cu2O and FeO respectively.

The roasted ore is heated with coke and sand in a furnace. Here FeO combines with SiO2, forms slag, and is removed, the unreacted FeS reacts with Cu2O to form Cu2S and FeO. Now the molten mass is called matte or Course metal.

The molten matter is introduced in the Bessemer converter and heated in the air. CuS and FeS are oxidized completely to Cu2O and FeO respectively. FeO slag is removed. Cu2S reacts with Cu2O to form Copper. The molten mass is allowed to cool, and when the dissolved SO2 is given out producing blisters. This copper is called Blister copper. It contains 2% impurities, this blister copper is purified by two methods

Poling method:

The blister copper is melted when oxygen is present. The impurities form their oxides and pass out in the gas form or as scum. The copper obtained is 99.5% pure by this method.

Electrolytic method:

The Impure metal is the anode, thin piece of pure metal is the cathode. An acidified solution of copper sulfate is used as an electrolyte. On passing electric current, pure metal is deposited on the cathode. The impurities settled down as anode mud.

Properties

Copper is a red-orange metallic luster. A freshly cut copper has a pinkish-orange color. The copper melting point is 1084 °C and the boiling point is 2562 °C. Its density is 8.96 g/cm3. Copper is an excellent conductor of heat and electricity.

Uses

1. Due to its high heat and electric conductivity, copper is used for making electric cables and other electrical appliances (wiring and motors).

2. Copper is used in construction (roofing and plumbing) and industrial machinery (heat exchangers).

3. Copper sheets are used for making utensils.

4. Copper forms several alloys like brass, bronze, etc. Its alloys find various uses in many industries.

5. Copper is used in electroplating, electrotyping, and making coins.

6. Salts of copper are used in insecticides and pesticides.

7. As copper has anti-biofouling properties, it is used in the aquaculture industry.

8. Copper compounds like Fehling's solution are used to detect sugars in the sample.

9. Copper and its compounds are used as catalysts in many chemical reactions.

10. Organo copper reagents are used in many chemical reactions.