Chapter 2: Collectors

2.1 CLASSIFICATION

On a broad basis, collectors can be defined as organic chemical substances in which the molecular structure is divided into a non-polar and a polar group.

The non-polar portion of the collector molecule is a hydrocarbon radical, which does not react with water and is therefore water-repellent. In contrast to the non-polar part of the molecule, the polar part can react with water. A typical example of such a heteropolar molecular structure is sodium oleate (Figure 2.1).

Figure 2.1: Molecular structure of sodium oleate.

The collector structure and composition determines its activity in relation to water dipoles. In the adsorption process of the collector on the mineral surface, the non-polar group of the collector is oriented toward the water phase and the polar parts toward the mineral surface. With this orientation, the mineral surface is rendered water-repellent (hydrophobic). Chemicals that are apolar hydrocarbon liquids (without a heteropolar structure) and that do not dissociate in water are also used as collectors.

Because the purpose of collectors is to render minerals water-repellent, these reagents are usually classified according to their ability to dissociate into ions in aqueous solution and having regard to which type of ions (anion or cation) gives the waterrepelling effect [1].

When a collector dissociates into cation and anion, the one that is the direct cause of the water-repellent action, may be called the active repellent ion, and the other the non-active (non-repellent) ion. The repellent ion structure always includes a hydrocarbon radical, the presence of which...