Depressants

Product Overview

Depressants facilitate the separation of sulfide ores either by depressing gangue minerals and floating the desired mineral, or by holding down the desired mineral while floating the undesirable gangue.

Note: Although a reagent is a depressant for one mineral/collector combination, it does not necessarily follow that it is a depressant for other combinations.

Depressant applications

These depressants are shown with their typical applications:
Sodium Metabisulfite: Depression of Zn sulfide (sphalerite) and Fe sulfide (e.g. pyrite, pyrrhotite) minerals. 
Sodium Sulfide / Sodium Hydrosulfide: At low dose rates (below 500 g/t) , can be used to depress Zn sulfide (e.g. sphalerite) and Fe sulfide (e.g. pyrite, pyrrhotite) minerals. At high dose rates (above 500g/t), it can be used to depress all sulfides (reverse flotation), allowing gangue to float and be removed.
Sodium Cyanide: Strong sulfide depressant for iron and zinc sulfides (e.g. pyrite, pyrrhotite, marcasite, arsenopyrite, sphalerite).
Lime: Depressant for pyrite during copper and zinc flotation and in other sulfide ores where pyrite is a problem.
Carboxymethyl cellulose: Depression of silicate gangue (e.g. talc, serpentine, lizardite, antigorite)
Guar Gum: Depression of silicate gangue (e.g. talc, serpentine, lizardite, antigorite)
Zinc Sulfate: Depression of zinc sulfide from lead and copper sulfide minerals. Can be used alone or in conjunction with cyanide.
Dextrin: Mostly used to depress carbon minerals during sulfide flotation. Can also be used to depress galena.