Skip to content Skip to footer

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).
OAN Depressant is a series of polymeric depressants specifically engineered to counter the
contaminating effects of naturally floating gangue minerals. It selectively adsorbs onto the surfaces of
the hydrophobic gangue minerals, thus reducing their tendency to float in froth flotation processes.
It 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.
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.


  • Improved flotation performance.
  • Increased grade/recovery.
  • High selectivity leading to significantly improved grade and recovery.
  • Improved flotation selectivity.
  • Improved rock concentrate.