ABSTRACT
Flotation is carried out in a flotation machine containing a water suspension of the minerals to be separated. The most important flotation reagents of all, ultimately, are the flotation collectors, since they are the substances that actually convert naturally occurring hydrophilic minerals into hydrophobic solids. They are invariably heteropolar substances that function by attaching themselves through their polar group(s) to a mineral surface. Usually, the polar group(s) are ionic. Thus, most collectors fall into three classes, anionic, cationic, or amphoteric, depending on the functional group(s) in the collector's structure. Cationic collectors generally possess long hydrocarbon chains, eight carbon atoms or longer in length. Important variables regarding the collecting properties of amphoteric surfactants, in addition to those of conventional cationic and anionic collectors, include the pka values of both the anionic and cationic groups and the isoelectric point values.
