Froth Flotation (Sulphide & Oxide)

Froth Flotation (Sulphide & Oxide)2017-04-04T06:57:31-04:00
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Depression of Iron and/or Silica in Zn-Pb sulphide flotation (4 replies and 1 comment)

3 years ago
Bobson 3 years ago

My plant uses a rather unusual pH 8 Galena-Sphalerite bulk float.

Main contaminants of concentrate in the form of Silica, Magnetite, Pyrrhotite and Fe amphibole.  Very high degree of liberation with minimal lockings - Entrainment is in part responsible but not the whole story. It seems that with overdosage of acid iron minerals are floating. 

Does anyone have any depressants or strategies they think would help to depress Silica, Magnetite, Pyrrhotite and/or Fe amphibole?



KM Edwards
3 years ago
KM Edwards 3 years ago

In reverse flotation of magnetite (ie float the silica) they often use starch as a depressant. The collector is aimed at grabbing the silica and is an amine (lilaflot if I remember correctly).

You could atleast get the magnetite out if you treated it in a Low Intensity Magnetic separator first (or after) and might be able to get other iron species with a High Intensity mag sep???



3 years ago
Bobson 3 years ago

Thanks for the response and suggestions KM.

I have been looking at carrying out some lab tests with starch/dextrine but there are so many different types and solubilities. I assume I need the most water soluble type but have also read about plants using "yellow" dextrine. Do you have any experience with this? 

We have done some magnetic separation tests (high and low intensity) in the lab but tend to lose quite a bit of zinc to the magnetic concentrates.

J. Neumann
3 years ago

Dextrin works well at depressing pyrite. I am not sure how it will do with other Fe minerals.

Sometimes basic food grade corn starch also will do the job. Best to raise the pH when mixing if you make your own batch.

3 years ago
Robert 3 years ago

What is present reagent regime?

Do you know where the contaminants are floating along the rougher bank, i.e., early, late, evenly, ...

3 years ago
Bobson 3 years ago

We adjust the pH with sulphuric acid, use SIPX (sodium isopropyl xanthate) collector and Nasfroth 240 frother. The majority of reagent dosage happens at the head of the circuit. 

The contaminants are floating later in the rougher bank. 

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