Laboratory Testing & General Mineral Processing Engineering

Laboratory Testing & General Mineral Processing Engineering

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Separating arsenopyrite from pyrite (2 replies)

2 years ago
jasonmaguire99 2 years ago

Hi all, 

Our ore/float concentrate contains pyrite and arsenopyrite. I require a high arsenopyrite concentrate with as little pyrite in it as possible for some leaching testwork but have not had any luck.  Does anybody have any experience with this? I have tried using several reagents like hydrogen peroxide to float the pyrite out of the bulk concentrate, but the remaining concentrate has a low grade. 

I would be happy to buy a laboratory quantity of an external arsenopyrite concentrate but it doesn't appear to be sold by anyone. 

Thanks for your help 

Todd H
2 years ago
Todd H 2 years ago
1 like by David

There has never been much success in commercially separating arsenopyrite from pyrite by flotation.  There are some techniques that have been tried:

I have heard that a hot lime boil will oxidize the arsenopyrite enough so it does not float, you make a bulk sulfide concentrate, subject it to a hot lime boil, then float the pyrite off in the next stage.

If you search the internet you will find some mineral dealers who offer areseonpyrite samples.


Hope this helps.

Todd Harvey - Global Resource Engineering

2 years ago
Jorge 2 years ago

In some cases, it is important to evaluate options to recovery gold from tailings. As part of this lab work, the basic idea is to obtain a pyrite-arsenopyrite concentrate. Most of the gold can be reported in the arsenopyrite. For that reason, it is necessary to separate pyrite and arsenopyrite. It is common to find an arsenopyrite concentrate refractory to the cyanidation process. Other part of the research work is to find a process to treat this refractory material.

The first step is to produce pyrite-arsenopyrite concentrate at pH 9 to 10. Sulphuric acid can be used to regulate the pH and copper sulphate to active the sulphides. It is necessary to consider a collector such as PAX, 20 to 30 g/t is a good range to evaluate. The addition of frother is variable and depends on the mineralogy.

Once the pyrite-arsenopyrite concentrate is obtained by flotation, it is necessary to increase the pH from 10 to 12. Lime can be used to regulate the pH. Several tests should be performed to select the optimum pH level. The slurry is heated at around 65 oC, one more time, it is important to perform tests (e.g. 40 to 70oC) to evaluate the effect of the temperature on the flotation selectivity between pyrite and arsenopyrite. The separation process could need the addition of a strong xanthate (e.g. PAX, 10 to 20 g/t) and a surface modifier to reactive the floatability of arsenopyrite. The idea to depress the pyrite and float the arsenopyrite.

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