Mechanism of collector
The basic mode of collector action is the adsorption of reagent molecules or ions at the interface between minerals and water. The interaction between collectors and mineral surface can be divided into physical adsorption, chemical adsorption and surface chemical reaction. The main adsorption methods include ion adsorption, molecular adsorption, semi micelle adsorption and adsorption of reaction products of collectors on mineral surface.
(1) Ion adsorption
The adsorption of collector ions in pulp on mineral surface, such as xanthate adsorption on galena surface at pH > 5, and adsorption of oleic acid collector on calcium bearing minerals (fluorite, calcite, scheelite, etc.).
(2) Molecular adsorption
The adsorption of collector molecules dispersed or dissolved in pulp solution on mineral surface. The physical adsorption of non-polar molecules is mainly the adsorption of various hydrocarbon oils; the physical adsorption of polar molecules is mainly the adsorption of the undissolved molecules of xanthate, oleic acid and amine collectors at the solid-liquid interface.
(3) Semi micellar adsorption
When the concentration of collector is high enough, the non-polar groups of long hydrocarbon chain collectors are adsorbed on the mineral surface and associated to form two-dimensional micelles, which is called "semi micellar adsorption".
(4) Adsorption of reaction products of collectors on mineral surface
A series of reactions may occur during the interaction of collectors with other ions or mineral surfaces in the pulp, and some products in the reactions are adsorbed on the mineral surface. For example, xanthate can form hydrocarbon thiocarbonate (Rocos -) and peroxanthate (rocss0 -) by the action of xanthate on the surface of sulfide minerals or oxidation in pulp. They can be adsorbed on the surface of oxidized minerals and sulfide minerals respectively, resulting in collection.