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 with 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. They physically adsorb onto 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).
FMC flotation DEPRESSANTs are marketed under POLYDEP trade names.

POLYDEP is a series of polymeric depressants specifically engineered to counter the contaminating effects of naturally floating gangue minerals. POLYDEP selectively adsorbs onto the surfaces of the hydrophobic gangue minerals, thus reducing their tendency to float in froth flotation processes.
POLYDEP has proven itself effective in a wide range of mineral froth flotation processes, but is primarily used in sulfide mineral flotation (Ni, Cu and etc.) and potash. POLYDEP is offered in a wide range of chemistries and FMC’s unparalleled experience in mineral flotation allow us to suggest products suitable for most flotation processes.

Depressants are required to give a low affinity to active sites on valuable mineral surfaces and a high affinity for gangue minerals and some sulfides. Typically, depressants prevent collector adsorption or bubble attachment to unwanted mineral surfaces. This increases the selectivity of flotation, rendering certain minerals hydrophilic and preventing them floating to the surface.
FMC supplies a range of POLYDEP S Series Depressants.



Third Floor, Sunnyar Tower, Azadi St., Hezar Jarib St., Isfahan, Iran


Phone Number

Fax: (+98) 3136696320 , Tel: (+98) 3136697042

(+98) 9129376700