Reagents are the most important part of the flotation process. In the early stage of the development of the flotation process, the major advances were due to better flotation reagents. In developing a treatment process, much time, energy and attention is spent on the selection of reagents to give the most effective separation and concentration results. In commercial plants, the control of reagent additions is the most important part of the flotation strategy.

Modern classification of the reagents is based on the function of a particular reagent. On this basis, reagents are divided into collectors, frothers, regulators and depressants. Several thousands of chemicals were either tested or suggested as flotation reagents. Nowadays, there are only a few hundred of these reagents that are extensively used in flotation.

Collectors are a fairly large group of organic chemical compounds, which differ in chemical composition and function. The basic purpose of the collector is to selectively form a hydrophobic layer on a given mineral surface in the flotation pulp and thus provide conditions for attachment of the hydrophobic particles to air bubbles and recovery of such particles in the froth product.

According to the ability of collectors to dissociate in water, they can be divided into distinct groups. Ionizing collectors consist of heteropolar organic molecules. Depending on the resulting charge, the collector assumes the character of a cation or anion. Anionic collectors are further classified into oxhydryl and sulfhydryl collectors on the basis of their solidophilic property.

Cationic collectors...