Aluminum sulfate

Aluminum sulfate . It is a solid, white-colored salt of formula Al2 (SO4) 3 which, due to its physico-chemical properties, is used mainly as a coagulating and primary flocculating agent in the treatment of water for human consumption and wastewater. It is characterized by grouping solids suspended in water and accelerating sedimentation, contributing to the decrease of bacterial load, as well as the removal of color and flavor.


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  • 1 Physical-Chemical Properties
  • 2 Obtaining Aluminum Sulfate
  • 3 Uses and applications of aluminum sulfate.
    • 1 Main applications
  • 4 Presentation of Aluminum Sulfate in the Market
    • 1 Products available
  • 5 Source

Physical-Chemical Properties

  • Appearance and Color: Bright white crystalline powder.
  • Smell: Odorless.
  • Vapor pressure: Not applicable.
  • Relative density (water = 1): 2.71
  • Solubility in water: High.
  • Molecular Weight: 342.14

Obtaining the Aluminum Sulfate

Aluminum sulfate is obtained by reacting an aluminum mineral ( kaolin , bauxite , aluminum hydrate ) with sulfuric acid at elevated temperatures; The reactions that are carried out depending on the aluminum mineral used are the following:

With bauxite: Al 2 O 3 + 3H 2 SO 4 ——–> Al 2 (SO 4 ) 3 + 3H 2 O.

Through aluminum hydroxide 2 Al (OH) 3 + 3 H 2 SO 4 + 10 H 2 O? Al 2 (SO 4 ) 3 16 H 2 O.

Once the aluminum sulfate is obtained, it has two presentations: solid and liquid, with 2 specifications, standard and iron- free .

Uses and applications of aluminum sulfate.

Technical grade aluminum sulfate in liquid state is a high quality solution that is generally used for clarification of water for human consumption and in wastewater. Through the use of aluminum sulfate in solution, the high degree of efficiency and versatility of this product has been demonstrated in the field of water clarification.

Main applications

  • Aluminum sulfate in the pulp and paper industry. PH adjustment, gluing ( pitch or wax ) and retention adjustment (fine, load, pigments, etc.) in addition to serving in the treatment of its effluents.
  • Aluminum sulfate for wastewater treatment. Aluminum sulfate is an economical and effective product in phosphorus removal in wastewater treatment plants for both human and industrial use and clarifies water by precipitating suspended solids.
  • Aluminum sulfate for the treatment of drinking water. Aluminum sulfate makes it possible to clarify drinking water since it is a coagulant and therefore sediments suspended solids, which due to their size will require a very long time to settle.
  • Aluminum sulfate in chemical manufacturing. It is used in the production of other aluminum salts.
  • Aluminum sulfate in the soap and grease industry. It is used in the production of aluminum soaps and greases for industrial uses.
  • Aluminum sulfate in the Petroleumindustry .- Manufacture of synthetic catalysts.
  • Aluminum sulfate in the Pharmaceutical industry.- As an astringent in the preparation of drugsand cosmetics .
  • Coloring fixing agent in textiles.
  • Manufacture of dyes such as carmine.
  • Sugar industry: As purifier molassesfrom sugar cane .
  • Other uses: As a coagulant in the manufacture of synthetic butadiene styrene rubber. For the manufacture of double salts, ammoniumand aluminum and potassium and aluminum sulfates , known as alum. For the purification of glycerin . As a fire retardant .

Presentation of Aluminum Sulfate in the Market

The consumer of aluminum sulfate has the option of choosing between the solid and the liquid product. The trend followed so far in all industrialized countries is towards an increasing use of the liquid for the following advantages:

  1. Easier handling, loading and unloading by pump, requires no unit to break sacks and dissolve, requires less labor.
  2. Constant concentration, for immediate use (sometimes the solution of the solid has concentration oscillations)
  3. It allows greater control in the dosage of the process, which avoids variations.

However, the solid offers the following advantages:

  1. Where the installation of tanks for liquid product storage is not justified
  2. In extremely cold areas that can cause freezing during transport and storage.
  3. When the consumer is very far from the production plant, the cost of dry base freight is reduced.

Traditionally, aluminum sulfate has been the coagulant that dominates the market due to its low cost and its easy obtaining, for these reasons most of the plants are designed to work with aluminum sulfate.

Currently, there are more efficient aluminum salts on the market that with lower doses, better contaminant removals are obtained in these products, the applied cost is less than the applied cost of aluminum sulfate.

Available Products

  • Aluminum sulfate powder or granular
  • Liquid Aluminum Sulfate
  • PAC’S Aluminum Polychloride Powder
  • Aluminum Polychloride PAC’S Liquid


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