Abstract
In removing the suspended fine particles from waste and muddy water, it is necessary to fasten their settling velocity by grouping particles as large flocs. Although nowadays organicflocculants have been used to flocculate suspended fine particles it is still hard to deal with the obtained sediment because of the moisture including in it. The use of non organic flocculant is unfortunately limited because of the tendency of flocculant ions to remain into the clarified water. So new flocculants should be developed to cope with these environmental problems.
In their previous studies on flocculation, dispersion phenomena and zeta-potential measurement of fine particles in aqueous suspension, authors had established that the zeta-potential of fine particles especially smaller than 6.54μm is one of the factors which rules the flocculation and dispersion phenomena since flocculation occurs between minerals with opposite sign of zeta-potential. Usually most of suspended particles in waste water have a negative value of zeta potential. So it is expected that the addition of minerals with a positive value of zeta potential such as fluorite will lead to thehetero-flocculation of particles and hence fasten the velocities of suspended particles.
In the present study, the effect of fluorite as flocculant has been investigated carrying out experiments on four types of fluorite sample (natural fluorite powder F93 and F92, artificial fluorite powder and suspension) and two types of waste water (fluorite flotationtailing from Kyoei Chemical Industry and bauxite residue from an alumina refining factory) It is noticed that fluorite suspensions have a better effect on flocculation of flotation tailing than fluorite powder. Besides artificial fluorite suspension even in small quantity is more effective than natural fluorite suspension. As for bauxite residue it is clarified by adding a large amount of artificial fluorite but the settling of flocs is very low (4mm/minute).
