ELECTROKINETICS OF OXIDIZED COAL

Electrokinetic measurements were carried out in order to determine the properties of oxidized coal surfaces over a wide pH range both in the presence and absence of various metal ions and flotation collectors. It was found that polyvalent cations, such as Fe++, Fe+++ and Al+++ decreased the zeta potential to zero and then reversed the charge. In the presence of cationic collectors, the negative value of zeta potential of oxidized coal was driven positive, below 9.3 to 10.9 depending on the type and concentration of collector used. The infrared spectra of oxidized coal did not indicate any characteristic bands for amine at any pH. These studies demonstrated that amines are not chemically adborbed on oxidized coal surfaces. © 1990.