Sodium Metabisulphite Supplier South Africa

What Is Sodium Metabisulphite?

Sodium metabisulphite (SMBS, Na₂S₂O₅) is an inorganic sulfite salt that releases sulfur dioxide (SO₂) in aqueous solution and in acid conditions. In flotation chemistry, SMBS is a reducing depressant — it reduces oxidised surfaces on iron sulphides (pyrite, pyrrhotite) and some other minerals, destroying or competing with collector adsorption sites and thereby suppressing their flotation. SMBS is particularly effective for pyrrhotite depression in nickel and PGM circuits, where pyrrhotite is the most problematic iron sulphide gangue mineral and is difficult to depress with lime or cyanide alone.

Pyrrhotite and Pyrite Depression

In PGM and nickel flotation, SMBS (often abbreviated NaMBS in South African mining practice) is the primary depressant for pyrrhotite, added to the mill or flotation circuit at dosages of 0.5–5 kg/t depending on pyrrhotite content and circuit requirements. SMBS reduces the oxidised pyrrhotite surface, destroying the mixed potential that drives collector adsorption and producing a hydrophilic surface that resists flotation. It is commonly used in combination with other depressants (lime for pH, carboxymethyl cellulose for additional selectivity) in a multi-component depression package. In gold leaching, SMBS is used to destroy excess cyanide (cyanide detox) in tailings water treatment.

Imininingwane Yokunikezwa

Terracore Chemicals supplies sodium metabisulphite in 25 kg bags and 1 MT bulk bags to mining operations and water treatment facilities across Southern Africa. Technical data sheets and application guidance for depressant circuit design are available on request.