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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.

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. 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.

froth floatation Depressants


  • Advantages:
  • Improved flotation performance.
  • Increased grade/recovery.
  • Improved flotation selectivity.
  •  Improved rock concentrate.
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