ABSTRACT
Coagulants and flocculants are chemicals used to aid the solid/liquid separation processes that are important in mineral beneficiation. This chapter describes why coagulants and flocculants are needed and what chemicals are used as flocculants and coagulants in mineral processing. Coagulants and flocculants are chemicals used to achieve the desired settling rate, acceptable clarity, and acceptable underflow density in clarification processes. They are also used in dewatering applications to increase production rates, as well as to help in providing a filter cake with acceptable handling properties. Although some inorganics, principally alum and iron salts, are still used as coagulants, water-soluble organic polymers are more commonly used as coagulants. Both naturally occurring and synthetic polymers find use as coagulants and flocculants in the mining industry. The most widely used synthetic coagulants are polydiallyl dimethyl ammonium chloride and condensation polymers of dimethylamine and epichlorohydrin. Coagulants and flocculants are used in a number of different processes in coal preparation plants.
