CAS #: 1327-41-9, Poly aluminium chloride (Aln(OH)mCl3n-m) is a yellow powder and a highly effective coagulant. It finds applications in a wide range of industries including use in personal care products, a flocculant in the purification of water such as swimming pools and in the potable and waste water treatments. It is also used largely within the paper and pulp industry.