Aluminum sulfate (chemical formula: Al2(SO4)3) is a widely used industrial reagent, often confused with alum. Aluminum sulfate is usually used as a flocculant in the purification of drinking water and sewage treatment equipment, as well as in the paper industry. Under natural conditions, aluminum sulfate hardly exists in the form of anhydrous salts. It forms a series of hydrates, of which aluminum sulfate hexahydrate is the most common. Aluminum sulfate is also a very effective mollusk insecticide, killing Spanish slugs.