Froth flotation separation and analysis
A method of separating heavy mineral particles, such as zircon, monazites, xenotime etc., from a sample of quartz crystal powder, comprises the steps of: a. conditioning the quartz powder suspected of containing heavy mineral particles as an aqueous pulp using a froth-flotation agent; b. subjecting the conditioned pulp to froth flotation to obtain a tailing; c. combining the tailing with an aqueous solution having a density greater than that of quartz and less than that of a heavy mineral which it is desired to separate; and d. centrifuging the combination. The separated heavy mineral crystals can then be characterized using a micro-analysis technique.
1. A method of separating heavy mineral particles from a sample of quartz crystal powder, comprising the steps of:
a. conditioning the quartz powder suspected of containing heavy mineral particles as an aqueous pulp using a froth-flotation agent;
b. subjecting the conditioned pulp to froth flotation to obtain a tailing;
c. combining the tailing with an aqueous solution having a density greater than that of quartz and less than that of a heavy mineral which it is desired to separate; and
d. centrifuging the combination.
2. A method of analysing heavy minerals present in a quartz powder, comprising the steps of separating the heavy minerals using a method according to claim 1 ; and characterising the separated heavy mineral crystals using a micro-analysis technique.
3. A method according to claim 2 , wherein the micro-analysis technique comprises at least one of optical microscopy, Raman microscopy, Energy Dispersive Analysis by X-ray (EDAX), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), or Laser Mass-spectrometry.
4. A method according to claim 1 , wherein the aqueous pulp is pH-controlled.
5. A method according to claim 4 , wherein the aqueous pulp is acidic.
6. A method according to claim 1 , wherein the froth-flotation agent comprises an anionic promoter.
7. A method according to claim 6 , wherein the anionic promoter is a petroleum based sulphonate promoter.
8. A method according to claim 1 , wherein the aqueous pulp has a pH of between 2 and 3.5.
9. A method according to claim 6 , wherein the promoter is added in a dosage of between 0.5 and 5 ml per kilogram of quartz powder.
10. A method according to claim 1 , wherein the quartz powder has a particle size of between 25 and 1000 μm.
11. A method according to claim 1 , wherein during conditioning the pulp is 65 to 75% solids by weight.
12. A method according to claim 1 , wherein conditioning takes place for 5 to 20 minutes.
13. A method according to claim 1 , wherein during froth flotation, the pulp is 10 to 30% solids by weight.
14. A method according to claim 1 , wherein flotation takes place for 5 to 60 minutes.
15. A method according to claim 1 , wherein the aqueous solution is a solution of one or more alkali metal polytungstates or heteropolytungstates.
16. A method according to claim 1 , wherein the aqueous solution is a solution of sodium heteropolytungstate.
17. A method according to claim 1 , wherein the aqueous solution has a density of 2.68 to 2.95 g/cm 3 .
18. A method according to claim 1 , wherein a non-vitreous vessel is used for centrifuging in step (d).
19. A method according to claim 1 , including the step of agitating a floating layer primarily of quartz in the centrifuged product, and re-centrifuging.