Chemical Industry
The chemical industry is defined as one that uses chemistry to make chemicals from other chemical substances (raw materials)
The important raw materials used in the chemical industry include (i) air, (ii) CaCO3, (iii) seawater and rock salt, (iv) Sulphur (v) Metallic mineral ore (vi) Coal, (vii) Natural gas and petroleum.
Sources of Raw Materials in The 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 limestone, chalk and marble is the source of lime or calcium oxide, fertilisers which are 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 deposits and in seawater. 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 textiles 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 hydrocarbons obtained from fossil fuel. The chlorohydrocarbons are versatile raw materials. They are used in the making of synthetic rubber, paints removers, refrigerants and several types of insecticides and industrial cleaning.
Sulphur
This is an element which is obtained naturally from the ground by the Frasch process or iron pyrites (FeS2), copper pyrite (CuFeS2), gypsum (CaSO4.2H2O) and anhydrite, which are the raw materials in chemical industries where SO2, H2SO3, and H2SO4 are produced. From the acids, compounds like (NH4)2SO4 (fertiliser), paints, dyes, explosives, synthetic fibres and accumulators are manufactured.
Natural Gas and Petroleum
This 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 fertilisers, 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, fertilisers 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 fertilisers 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
The fertiliser industry is important. Fertilisers such as NH4NO3, (NH4)2SO4 and Urea, as well as pesticides, insecticides, germicides, herbicides and fungicides are all products of the petrochemical industry, which helps in agricultural production.
Paint Industry
Paint is a fluid mixture which contains 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 fasten stones and bricks together. The mixture called mortar hardens like stone.
Plastic Industry
The plastic industry is divided into four categories: bags, household 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 the modern plastic industry are obtained by fractional distillation of crude oil or 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
EVALUATION
- What is the chemical industry?
- List two types of chemicals
- List the types of chemical industry
WEEKEND ASSIGNMENT
- Examples of heavy chemicals include the following, except (a) NaOH, (b) Perfumes
(c) H2SO4 (d) NH3
- Fine chemicals have the following characteristics, except (a) they are chemically pure
(b) They are produced by batch process (c) They are produced in large quantities because of high applicability (d) They are produced in small quantities because of limited applicability
- Plastics are polymers whose production technique involves the following, except (a) High pressure (b) low temperature (c) High temperature (d) Setting
- Metallurgy is a scientific process which involves the following except (a) manufacture of alloys (b) manufacture of both natural and artificial catalysts (c) refining of metals (d) grading of metal
- The major difference between cement and mortar is that (a) mortar hardens by giving off water (b) Cement hardens by giving off water (c) mortar is always white (d) Cement is always coloured because of superheating
THEORY
- (a) Give one example of (i) Heavy chemicals, (ii) Fine chemicals (b) Name the major raw materials used in the manufacture of the following: (i) Polythene, (ii) Cement (iii) Soap
- (a) What is a chemical industry? (b) Mention three types of chemical industries