Hi Vahid,

I think Magnetic Separation works.

Hi Vahid

The answer is not easy.

It will depends on the type of economic element/mineral of the ore: fine gold, cassiterite, palatinum grains, diamonds. It will also depends on how similar is the behaviour (grain size, magnetic susceptibilty, density, etc) between the element/mineral of interest and non economic minerals. It is possible to apply directly a magnetic or a gravity separator ? It is possible to apply a flotation technique ? I hope this new questions could help you.

Try magnetic separation as pre-concentration of sized products, to remove main diamaganetics like quartz., as ilemenite, titanomagnetite are ferro magnetics and pyroxene seems to be paramagnetics. Please run a diagnoistic process test in mineralogy lab using sink- float test,. hand magnet - Frantz Iso dynamic test on screened fractions to see the amenability of sample to size, specific gravity and magnetic suceptability. Dr B P Ravi IBM Ajmer

Dear Vahid;

Sequences for physical separation methods and flow-sheet development normally related to a lot of parameters such as liberation degree, difference in gravity of specific gravity of different size fractions, what is your final target. As almost of contributors already said combination of gravitational separation and magnetic separation can be useful but please keep in mind that investment for magnetic separation is too high in comparison with gravity separation therefore economically is logical to treat your sample firstly with multi stages of gravity separation and thereafter try to use magnetic separation. In some case removal of diamagnetic minerals (such as quartz) from other Ferro or Para magnetic minerals (such as ilmenite, pyroxene, titanomagnetite) by magnetic separation and further works with gravity separation can be interesting. Also please keep in mind limitation of feeding size for each equipment (for example is your particles are finer than 0.1 mm it is better to use slime-table or Multi Gravity Separator (MGS) (especially for particles finer than 30-40microns; for  intermediate size range there is competition between shaking table and Spiral. In some case maybe you may use Jig for pre-treatment of coarse particles which is followed by grinding and further physical separation. Bu with respect to my experiences I prefer Spiral or Richard cones (especially for size range of 0.1-0.6 mm) which is followed by multi-stages of magnetic separation (different stages and different magnetic field intensity). Also I advice you to check preliminary sink-float tests in different size fraction (it has good view about further steps.

Regards,

HH