The inhibition principle and application of zinc sulfate inhibitors

The inhibition principle and application of zinc sulfate inhibitors

In order to improve the selectivity of the flotation process, enhance the effects of collectors and foaming agents, reduce the mutual inclusion of useful component minerals, and improve the slurry conditions of flotation, regulators are often used in the flotation process. Adjusters in the flotation process include many chemicals. According to their role in the flotation process, they can be divided into inhibitors, activators, medium adjusters, defoaming agents, flocculants, dispersants, etc.

During the froth flotation process, inhibitors are agents that can prevent or reduce the adsorption or action of the collector on the surface of non-flotation minerals, and form a hydrophilic film on the surface of the minerals.

Zinc sulfate is one of the important inhibitors in the froth flotation process.

The inhibition principle of zinc sulfate inhibitor
In mineral processing production, zinc sulfate, lime cyanide, sodium sulfide, etc. are commonly used inhibitors.Zinc sulfate is a good zinc blende inhibitor when used in combination with other agents.

What is the inhibition principle of zinc sulfate?

Usually, the inhibitory effect only works in alkaline pulp. The higher the pH, the more obvious the inhibitory effect. In water, zinc sulfate reacts as follows:

ZnSO4 = Zn(2+)+SO4(2-)

Zn(2+)+2H2O=Zn(OH)2+2H(+) [Zn(OH)2 is an amphoteric compound, dissolves in acid and forms a salt]

Zn(OH)2+H2SO4 = ZnSO4+2H2O

In alkaline media, HZnO2(-) and ZnO2(2-) are produced, which are adsorbed on minerals and enhance the hydrophilicity of the mineral surface.

Zn(OH)2+NaOH=NaHZnO2+H2O

Zn(OH2+2NaOH=Na2ZnO2+2H2O

In mineral processing, zinc sulfate is generally not used alone as an inhibitor, but is often used in combination with cyanide, sodium sulfide, sodium carbonate, etc. The commonly used ratio is: cyanide: zinc sulfate = 1:2~5. The combined use of sulfuric acid and cyanide can enhance the inhibitory effect on sphalerite.

Application of zinc sulfate inhibitors
Zinc sulfate is a strong acid and weak alkali salt, often with 7 crystal water (ZnS·7H2O), pure product (anhydrous), white crystal, easily soluble in water. The zinc sulfate content in its saturated solution is 29.4%, and the aqueous solution is acidic. . In production, it is often used as a 5% aqueous solution.

When zinc sulfate is mixed with lime, it is an effective inhibitor of zinc sulfide minerals (zinc blende or iron blende). The higher the pH value of the slurry, the stronger the inhibitory effect of zinc sulfate on zinc sulfide minerals.

It is generally believed that the inhibitory effect of zinc sulfate on zinc sulfide minerals is due to the adsorption of Zn(OH)2, HZnO2(-), or ZnO2(2-) generated in alkaline media to the surface of zinc sulfide minerals to form a hydrophilic film. Caused by.

Zinc sulfate is sometimes mixed with cyanide and lime. The descending order of their inhibition of metal sulfide minerals is: sphalerite > pyrite > chalcopyrite > marcasite > bornite > chertite chalcocite mine. Therefore, when separating polymetallic sulfide minerals, the dosage of inhibitors must be strictly controlled.