Ferric & Non-Ferric Alum Plant

Bauxite ore is available from the market as lumps with 54 - 58% Alumina as Al 2O3 . The Al2O3 percentage should be 57-58% to produce A grade ferric alums. Technical grade Sulphuric acid having concentration of 98.5% is used for the process . The spent Sulphuric Acid which is 70% to 90% pure can also be used partially with 98.5% Acid.

MANUFACTURING PROCESS :
The raw materials for ferric alums are

1. Bauxite
2. Sulphuric acid

The Bauxite lumps are crushed to –20mm size with help of a Jaw crusher . The crushed material is fed in to a open circuit ball mill to grind it to 90% passing through 100 mesh size. This ground Bauxite powder is stored in the storage Hopper.The Digester has Lead and AHR lining . A measured quantity of water or recycled liquor is fed into the digester. A measured quantity of Sulphuric Acid or Spent Acid is added to the Digester. The temperature of the diluted Acid rises due to the liberation of heat of dilution. Now, the powdered Bauxite is added slowly and carefully. The reaction is vigorous and the reaction proceeds with frothing. The reaction temperature goes up to 120 oC. The reaction is taken to the completion by adding Bauxite to neutralise the remaining Acid. The agitation with the compressed air is done as and when required.

The liquid is drained into the settling pit and allowed to settle for a few days.

The decanted liquid is taken to the evaporator where it is heated with steam coils. As the desired gravity of liquid is achieved, the liquid is taken to the moulds for casting.

The sludge is washed into a centrifuge. The liquid is recycled and the solid sludge is used for land filling.

The raw materials are :
For Ferric Alum :

• Bauxite
• Sulphuric Acid Technical Grade 98.5% pure.
• We can use spent Sulphuric acid along with conc.
• Acid in significant quantity.

FOR NON FERRIC ALUM ( ALUMINUM SULPHATE) :

1. Aluminum Hydrate
2. Sulphuric Acid Technical Grade 98.5% pure

Specific Raw Material Consumption (For Alum Containing Alumina as Al2O3 16 %)

Quantity required daily for 50 TPD Alum Plant

You can manufacture Ferric Alum, Non Ferric Alum( Aluminum Sulphate) and Liquid Alum from the same plant.