CHEMICAL INDUSTRIES

 

CHEMICAL INDUSTRY:

Chemical industry is defined as one that uses chemistry to make chemicals from other chemical substances (raw materials)

The important raw materials used in chemical industry include (i) air (ii) CaCO₃ (iii) Sea water and rock salt (iv) Sulphur (v) Metallic mineral ore (vi) Coal          (vii) Natural gas and petroleum.

SOURCES OF RAW MATERIALS IN CHEMICAL INDUSTRY

AIR: Air is the chief source of O₂ and N₂. N₂ is important because it is used in the manufacture of NH₃. NH₃ itself is used in the manufacture of trioxonitrate (v) acid which is used in the making of explosives, plastics and other materials. NH₃ is also used in the manufacture of NH₄⁺ salts like HN₄O₃, (NH₄)₂SO₄ which are used in manufacturing fertilizers.

 

CALCIUM TRIOXOCARBONATE (iv) (CaC0₃): CaCO₃ in the form of lime stone, chalk and marble is the source of lime or calcium oxide which is used for making concrete and cement. It can also be the source of raw materials for the production of baking powder and also for CO₂ which can be used to produce sodium trioxocarbonate (iv) by the Solvay process.

 

SEA WATER AND ROCK SALT: Salt or NaCl occurs as rock salt in underground deposit and in sea water. The sodium chloride salt is the major starting material for many chemical industries. Sea water is also the source of NaBr from which bromine is manufactured on large scale. Electrolysis of NaCl produces chlorine. The other main product is NaOH which is used in the manufacture of soap and textile and in petroleum refining, as well as other chemicals such as Na₂CO₃ which is also a source of material for the glass industry and in the manufacture of detergents. It is also used in the softening of water in the public water works department. The chlorine produced can be made to react with hydrocarbon obtained from fossil fuel. The chlorohydrocarbon are versatile raw materials. They are used in the making of synthetic rubber, paints removers, refrigerant and several types of insecticides and industry cleaning.

 

SULPHUR: is an element which is obtained naturally from the ground by Frasch process or iron pyrites (FeS₂), copper pyrite (CuFeS₂), gypsum (CaSO₄.2H₂O) and anhydride which are the raw materials  in chemical industries where SO_2,H₂SO₃, H₂SO₄ are produced. From the acids, compounds like (NH₄)₂SO₄ (fertilizer), paints, dyes, explosives, synthetic fibres and accumulator are manufactured.

 

NATURAL GAS and PETROLEUM: Petroleum is a major and very important raw material for petrochemicals like CH₄, ethane, propane, butane, ethyne, butadiene, isoprene, benzene and phenol. From these petrochemicals, other products and chemicals like fertilizers, agricultural motor fibre and plastics are made. These chemicals have their own different industries e.g. agricultural industries. Petroleum products like petrol, diesel, and kerosene were marketed by foreign oil companies like Shell, Mobil, Gulf and Texaco.

 

DIVISION OF THE CHEMICAL INDUSTRIES

Chemical industries can be classified on the basis of their products. We have chemical industries which produce:

(a) Basic chemicals such as acids, alkalis, salt and organic chemicals.

(b) Chemical products that are used in the manufacture of artificial fibres and plastics.

(c) Chemical products used as starting materials in other industries that manufacture substances such as paints, fertilizers    and explosives.

(d) Chemical products such as cosmetics, drugs and soap for personal use.

 

HEAVY AND FINE CHEMICALS

Heavy Chemicals: They are classified as heavy chemicals because they are required in large quantities in different types of chemical industries all over the world. Heavy chemicals includes tetraoxosulphate (vi) acid (the most important) hydrochloric acid, trioxonitrate (v) acid calcium trioxocarbonate (iv) acid, caustic soda (sodium hydroxide), Slaked lime, Ca(OH)₂  and their special derivative, such as Caustic potash, Sodium trioxocarbonate(iv) acid, bleaching powder (CaOCl₂).

 

Metals such as iron, copper, tin, aluminium and zinc are also heavy chemicals, as well as organic materials such as coke, coal tar, benzene, and methyl benzene. NH₃ is also a heavy chemical. It is manufactured in large quantities and is used to make fertilizers as well as explosives.

 

FINE CHEMICALS: They are manufactured only in small quantities for paints and fuels, drugs, analytical chemicals, bulk of laboratory reagents acids photographic materials. Their purity is generally of a higher degree than that of heavy chemicals, and so they are correspondingly more expensive.

 

TYPES OF INDUSTRY

Due to different types of naturally occurring raw materials, many chemical industries are established some of these industries are:

Fertilizer Industry

Paint Industry

Cement Industry

Plastic Industry

Pharmaceutical Industry

 

FERTILIZER INDUSTRY: Fertilizer industry is an important industry. Fertilizers such as NH₄NO₃, (NH₄)₂SO₄ and Urea, as well as pesticides, insecticides, germicides, herbicides and fungicides are all products of petrochemical industry which helps in agricultural production.

 

PAINT INDUSTRY: Paint is a fluid mixture which contain suspended colouring materials. The main use of paints is for decoration and protection against weathering and corrosion.

 

CEMENT INDUSTRY: Cement is produced by heating a mixture of powdered lime (CaO) and clay. When mixed with water, it can be used to fastened stones and bricks together. The mixture called mortar hardens like stone.

 

PLASTIC INDUSTRY: The plastic industry is divided into four categories; bags, house hold and kitchen wares, industrial plastics supplies and miscellaneous items.

 

The industrial plastics supplies cover items such as casing for radios, Cassette recorders and TV sets, as well as PVC pipes and fittings for the building industry. The starting raw materials for modern plastic industry are obtained by fractional distillation of crude oil of petroleum. The major raw material in the plastic industry is ethene.

 

PHARMACEUTICAL INDUSTRY: Many plants extracts are known to have some medical properties. Most medicinal are organic compounds, but many inorganic substances are still used in pharmacy, for example; Potassium bromine, used as sedative, bismuth carbonate, used to cure stomach disorders, mercury nitrate, used as an antiseptic for skin diseases; and mercury (1) chloride, used as a strong purgative. Drug can be used to cure disease. Drug such as quinine for the treatment of malaria and insulin for the treatment of diabetes are examples. Many of our synthetic drugs, syringes, surgical and important materials in the hospitals are manufactured from petrochemical products. Disinfectants, Cosmetics, detergents and soap are also products of petrochemicals