Manufacturing of Sulphuric Acid - Contact Process
Sulphuric acid is mainly produced by the contact process.There are four main steps involved in the manufacture of sulphuric acid by contact process.In the first step, sulphur is oxidized to sulphur dioxide.The sulphur dioxide is then oxidized to sulphur trioxide.The sulphur trioxide obtained is then dissolved into sulphuric acid to form oleum.When oleum is diluted with water it gives sulphuric acid.This is the flow chart for the manufacture of sulphuric acid.Sulphur burner - In this sulphur is burnt to get sulphur dioxide.Dusting precipitator - It removes the impurities present in the sulphur dioxide and air.The gas is then led into the washing tower, where it is completely free from dust particles.The gas is dried by the spray of concentrated sulphuric acid in the drying tower.The gaseous mixture is then led into arsenic purifier where every trace of arsenic oxide is removed.The purified gases are then led into the pre heater, where the gases are preheated to 400 - 450 degree C by the hot gases, mainly, sulphur trioxide and nitrogen.The hot gases then are passed through the catalytic converter packed with vanadium pentoxide or platinum.Here the preheated mixture of sulphur dioxide and oxygen forms sulphur trioxide.The sulphur trioxide formed, is passed up through an absorption tower, where it meets a stream of concentrated sulphuric acid.The acid absorbs the sulphuric acid to form oleum.
Physical properties of sulfuric acid
Sulphuric acid is a colorless, dense, oily liquid.Specific gravity of sulphuric acid is 1.84 at 298 K.Sulphuric acid freezes at 283 K and boils at 611 K.It dissolves in water with the evolution of a large quantity of heat.
Uses of sulfuric acid
Sulphuric acid is important in the manufacture of fertilizers (E.g., ammonium sulphate, super phosphate).Sulphuric acid produced is also used in petroleum refining, manufacture of pigments, paints and dyestuff intermediates.Sulphuric acid is used as electrolyte in lead acid batteries.Sulphuric acid is used to remove rust from iron and steel before galvanising or electroplating.Sulphuric acid is often used to dry neutral and acidic gases, since it is a good dehydrating agent.Sulphuric acid is also used in detergent industry.