The Mechanism of Action of Collectors

The basic mode of action of collectors is the adsorption of the agent's molecules or ions at the mineral-water interface. The interaction between collectors and the mineral surface can be divided into three types: physical adsorption, chemical adsorption, and surface chemical reactions. Among them, the main adsorption methods include: ionic adsorption, molecular adsorption, hemimicellar adsorption, and the adsorption of collector reaction products on the mineral surface, and so on.

(1) Ionic Adsorption

This refers to the adsorption of collector ions in the pulp on the mineral surface. For example, when pH > 5, the adsorption of xanthates on the surface of galena, and the adsorption of oleic acid-based collectors on calcium-containing minerals (such as fluorite, calcite, scheelite, etc.).

(2) Molecular Adsorption

It is the adsorption of collector molecules (dispersed or dissolved in the pulp solution) on the mineral surface. Specifically, it includes two categories:

Physical adsorption of non-polar molecules: mainly refers to the adsorption of various hydrocarbon oils.

Physical adsorption of polar molecules: mainly involves the adsorption of undissociated molecules of xanthates, oleic acid, and amine-based collectors at the solid-liquid interface.

(3) Hemimicellar Adsorption

When the concentration of collectors is sufficiently high, the non-polar groups of long hydrocarbon chain collectors adsorb on the mineral surface and associate with each other to form two-dimensional micelles. This type of adsorption is called "hemimicellar adsorption".

(4) Adsorption of Collector Reaction Products on the Mineral Surface

Collectors may undergo a series of reactions in the pulp when reacting with other ions or the mineral surface, and some products of these reactions will be adsorbed on the mineral surface. For instance, xanthates can generate alkyl monothiocarbonates (ROCOS⁻) and perxanthates (ROCssO⁻) through reactions on the surface of sulfide minerals or oxidation in the pulp. These products can be adsorbed on oxidized mineral surfaces and sulfide mineral surfaces respectively, thereby exerting a collecting effect.

The above is the introduction to the mechanism of action of collectors. Do you understand it? If you want to learn more about collectors, you are welcome to follow our website.