Floatation Reagents

Collectors The principle role of the collector is to selectively adsorb and impart hydrophobicity to the mineral particles to be floated. These can be cationic in nature, such as amines, or anionic in nature, such as carboxylates, sulfonates, xanthates, or alkyl sulfates. Fatty acids, such as oleic and stearic, are also commonly used. 

Frothers The purpose of a frothing agent is to produce air bubbles in the floatation cell, which must then remain intact until they are skimmed off to collect the floated mineral particles. If the collector cannot act as a frothing agent on its own, then additional agents are added, such as pine oil, polyglycols, and cresylic acid. 

Activators If a mineral surface will not absorb a collector molecule, then floatation of that mineral will not occur. In this circumstance, special reagents, called activators, are added that allow the collector to bind to the mineral surface. An activator normally works by adsorbing onto the mineral surface, thereby providing sites for the adsorption of the collector species. 

Depressants The purpose of depressants is to inhibit or retard the floatation of a desired type of particle. Its mode of action is to either inhibit the collector molecule from adsorbing onto the particle surface or to mask the adsorbed collector species from the bulk solution so that the particle does not display a hydrophobic exterior surface in contact with bulk solution. Examples of depressants include starch, tannin, silicates, aluminum salts, and dextrin. 

Dispersants The presence of very fine particles, called slimes, in the floatation process can coat the larger particles and consume excessive quantities of reagents because of their high surface area. The addition of a dispersant, such as silicates, phosphates, or carbonates, clears the surface of the larger particles of slimes. 

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