For decades, Aluminum Sulphate, popularly known as alum has been used as a raw material in water treatment industry. Easy availability and large molecular size makes it an excellent flocculent for treatment of both potable water and industrial waste water. Alum also finds use in a diversity of other areas including construction products, oil / fat processing and paper manufacturing. It has many trade names such as Ferric Alum and Non Ferric Alum, Pearl Alum, Pickle Alum, "papermakers' alum" etc.
The raw material bauxite lumps are crushed to - 15 mm size in a Crusher and ground fine 90% passing through 100 mesh in a ball mill. The reactor is lead and Acid & heat resistant brick lined. The acid is diluted to 65-70% and bauxite powder is added slowly to neutralize the acid completely. As the reaction is over, the resultant solution is diluted to a fixed gravity with water and coagulant is added to precipitate the colloidal particles. The material is allowed to settle in settling tanks. The supernetant liquid is separated and evaporated with steam coils in evaporators. As the liquid achievers fixed gravity it is discharged in the moulds to make slabs. If the balls are to be manufactured, the spray technology is applied.
Some of the major components of Alum Plant are