DEPRAMIN® gangue depressants

The valuable minerals in ore deposits are usually associated with worthless materials, called gangue minerals, and the ore must be processed to liberate the valuable minerals and then separate them from the waste minerals. The most important method for this separation is froth flotation. This technique is a physico-chemical separation-process, based on a difference in hydrophobicity between the desired and unwanted minerals.

Chalcopyrite

In a flotation cell, air bubbles are the driving force to separate the minerals and the valuable minerals should float to the surface. The froth on the surface of the flotation cell thus concentrates the valuable minerals. The process is also called “concentration” and the froth is called “concentrate”.    Chemicals are added to enhance the difference in hydrophobicity between the minerals. The chemicals that render the mineral surfaces hydrophobic are known as collectors.

DEPRAMIN gangue depressants prevent gangue minerals like talc, serpentine, chlorite, anhydrite, from floating to the surface of the cell and thus reporting to  the float. This way, the grade of the concentrate is increased and minerals like MgO that often increase the smelting costs can be prevented from entering the froth. Next to this, DEPRAMIN depressants often also enhance the recovery  of the valuable minerals by separating them from the gangue minerals.    

In an ideal situation, collectors should adsorb selectively on the valuable minerals and depressants should adsorb selectively on the unwanted gangue minerals. Unfortunately, this is almost never the case and the right combination of collectors and depressants requires the development of dedicated chemicals and a lot of fine-tuning in the flotation process.    

At AkzoNobel we have successfully developed a range of DEPRAMIN depressants that depress selectively gangue minerals without depressing valuable base minerals like Pentlandite(Ni), Chalcopyrite (Cu) and precious metals like Gold, Platinum and Palladium.    

Thus, selectivity is the key to success. Each ore has unique characteristics with respect to the flotation of gangue minerals and selective DEPRAMIN grades need to be developed for that specific ore.

For a better understanding of the phenomenon of selectivity and the way we work at AkzoNobel Mining we recommend to click at the short course:

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