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Froth flotation is a process widely used to selectively separate valuable minerals from worthless gangue. The process relies heavily on the differences in the mineral surfaces’ hydrophobic character to accomplish this task.

Most minerals in nature are hydrophilic (non-hydrophobic) and do not readily float in froth flotation without the use of chemical reagents known as collectors.

  • Collectors -  physically adsorb on the precious mineral surfaces rendering the particles hydrophobic and “floatable”

The problem in froth flotation is that certain gangue minerals have hydrophobic surfaces and undesirably float contaminating the precious mineral concentrate. To negate the hydrophobic minerals tendencies to float, depressants are used.

  • Depressants - physically adsorb on the surface of gangue minerals rendering the particles hydrophilic and “non-floatable”.

The use of depressants allows for higher precious metal recovery and grades and can improve the economics of downstream processing (e.g. smelting costs)


AkzoNobel produces a series of polymeric depressants marketed under the name of Depramin specifically engineered to counter the contaminating effects of naturally floating gangue minerals. Depramin selectively adsorbs onto the surfaces of the hydrophobic gangue minerals reducing their tendency to float in froth flotation processes.

Depramin has proven itself effective in a wide range of mineral froth flotation processes, but is primarily used in:

  • Sulfide mineral flotation (PGMs, Ni, Cu)

  • Potash  

Depramin is offered in a wide range of chemistries and AkzoNobel’s unparalleled experiences in mineral flotation allow us to suggest products suitable for most flotation processes.

For more information, please contact us.