| dc.description.abstract |
The floatability of oxidized coal was investigated by means of electrokinetic studies, contact angle measurements and flotation tests. Electrokinetic measurements showed that the zeta potential of unoxidized and oxidized coal samples depends on pH. Hydroxonium and hydroxyl ions are potentially significant ions, both for oxidized and unoxidized coal. Increasing oxidation times decreased the measured iso-electric points and increased the negative zeta potential. In the presence of cationic collectors the negative value of the zeta potential for oxidized coal was changed to a positive value below pH 9.3-10.9 depending on the type and concentration of collector used. Contact angle measurements indicated that the natural flotability of unoxidized coal was found to deteriorate on oxidation. Addition of cationic collectors increased the value of the contact angle of oxidized coal. Flotation tests showed that as the degree of oxidation increases, the floatability of coal decreases. Cationic collectors were found to be effective in the flotation of oxidized coal. © 1995. |
|