Manufacturing Process:
Alum (Aluminum Sulphate) is manufactured by the reaction of  Alumina Hydrate and Bauxite with Sulphuric acid.
Bauxite is ground in the pulverizer to 90% passing through 200 mesh and elevated to Batch Hopper through Bucket Elevator. Measured quantity of water is to be taken into the Lead bonded reactor and slowly concentrated Sulphuric acid is to be added in the reactor. After getting the required temperature in the reactor, slowly the ground bauxite is added . After the addition of measured quantity of Bauxite/Alumina Hydrate, the Agitator is kept on for about 45 minutes then the solution is dumped into the settling tank.

The decanted solution of Aluminum Sulphate for the mixed process is then again taken to the Reactor and the required quantity of Sulphuric Acid is slowly added and after getting the temperature. The required quantity (as per the degree of solution) of Hydrated Alumina is slowly added keeping agitator rotating. After the addition of total quantity the Alum is molded in the trays with the help of tray filling arrangement. The slabs after cooling are to be taken out from the trays and stacked in the store.

The decanted solution for hot process is taken into the evaporator and the solution is concentrated to the required gravity and than molded in the trays for cooling.

What is Alum and how does it control Algae?
ALUM (aluminum sulfate) is a nontoxic material commonly used in water treatment plants to clarify drinking water. In lakes alum is used to control algae, not by killing the algal organisms, but by reducing the amount of the nutrient phosphorus in the water. Like most other plants, algae requires phosphorus to live and reproduce. Algal growth is usually limited by the amount of that mineral available in the water.

Phosphorus enters the water either externally, from run-off or ground water, or internally, from the nutrient rich sediments on the bottom of the lake. Phosphorus is released from the sediments under anoxic conditions that occur when the lake stratifies and oxygen is depleted from the lower layer.

Even when external sources of phosphorus have been curtailed by best management practices, the internal recycling of phosphorus can support explosive algal growth. Alum is used primarily to control this internal loading of phosphorus from the sediments of the lake bottom.
On contact with water, alum forms a fluffy aluminum hydroxide precipitate called floc. Aluminum hydroxide (the principle ingredient in common antacids such as Maalox) reacts with phosphorus to form an aluminum phosphate compound. This compound is insoluble in water under most conditions so the phosphorus in it can no longer be used as food by algae organisms.

As the floc slowly settles, some phosphorus is removed from the water. The floc also tends to collect suspended particles in the water and carry them down to the bottom, leaving the lake noticeably clearer.

On the bottom of the lake the floc forms a layer that acts as a phosphorus barrier by combining with phosphorus as it is released from the sediments. The floc is harmless to water creatures and aquatic plants. (Sorry, alum does not control rooted aquatic weeds.)