Aluminium sulfate is a widely used industrial chemical. It is sometimes incorrectly referred to as alum, as it is closely related to this group of compounds. It occurs naturally as the mineral alunogenite. It is frequently used as a flocculating agent in the purification of drinking water and waste water treatment plants, and also in paper manufacturing.Aluminium sulfate is rarely, if ever, encountered as the anhydrous salt. It forms a number of different hydrates, of which the hexadecahydrate is the most common.


General Description

Aluminum (Aluminium in British English) is a silver-white ( with a face-centered cubic crystalline structure), ductile and light metal element in the member of group IIIa of the periodic table. Symbol Al; Atomic number 13; atomic mass 26.98154; melting point ca 660°C; boiling point ca  2,467°C; specific gravity 2.6989 at 20°C; valence +3; electronic config. [Ne]3s23p1. Aluminium crystallizes in a face-centered cubic lattice that is stable from 4 K to melting point. It is an excellent conductor of heat and electricity (60% of copper’s).

Polymerization gradually proceeds to larger structures, eventually leading to the formation of the Al13 (polycation). As polymers coalesce, they increase in relative molecular mass, eventually becoming large enough to precipitate aluminium hydroxide from solution. Aluminum is one of the most abundant metals in the earth. It is not found in nature as the free element but in combination in clay, bauxite, mica, feldspar, alum, cryolite, and in the several forms of alumina such as emery, corundum, sapphire, and ruby (forms of aluminum oxides).

Aluminum is very important in world economy. A