Aluminium Sulfate

 

Aluminum Sulfate is used in water purification and as a mordant in dyeing and printing textiles. In water purification, it causes impurities to coagulate which are removed as the particulate settles to the bottom of the container or more easily filtered.

When dissolved in a large amount of neutral or slightly-alkaline water, aluminum sulfate produces a gelatinous precipitate of aluminum hydroxide, Al(OH)3. In dyeing and printing cloth, the gelatinous precipitate helps the dye adhere to the clothing fibers by rendering the pigment insoluble.

Aluminum sulfate is sometimes used to reduce the pH of garden soil, as it hydrolyzes to form the aluminum hydroxide precipitate and a dilute sulfuric acid solution.

In construction industry it is used as waterproofing agent and accelerator in concrete. Another use is a foaming agent in fire fighting foam.