Beneficiation of rare earth elements bearing ancylite
Disclosed herein are methods and systems for recovery of ancylite, a rare earth mineral comprising strontium carbonate, from rare earth ore. In many embodiments, the disclosed methods and systems provide for recovery of greater than 50% of the ancylite from an ancylite containing ore. In many embodiments, the ore is subjected to flotation in the presence of an acid, for example a hydroxamic acid, such as octanohydroxamic acid. The ore may also be subjected to magnetic separation, for example wet high intensity magnetic separation.
1. A method of increasing the concentration of a ancylite in an ore sample, the method comprising:
combining the ancylite containing ore sample and a collector comprising a hydroxamic acid;
agitating the ancylite/collector combination;
subjecting the agitated ancylite/collector combination to flotation and floating the ancylite/collector combination to obtain a tailing sink fraction and a concentrated ancylite float fraction;
separating the tailing fraction from the ancylite fraction, and thereby obtaining an ore sample with increased concentration of ancylite.
2. The method of claim 1 , wherein the ore sample has a mesh size less than about 100 mesh.
3. The method of claim 1 , wherein the flotation is performed by passing a gas through the combination.
4. The method of claim 1 , wherein the hydroxamic acid is octanohydroxamic acid.
5. The method of claim 4 , wherein the collector comprises octanohydroxamic acid and potassium ethyl xanthate.
6. The method of claim 1 , wherein the collector concentration is between about 0.003 and 0.0001 mol/liter.
7. The method of claim 1 , wherein the pH of the ancylite/collector combination is between about 6 and 11.
8. The method of claim 1 , wherein strontium nitrate is added to the ancylite/collector combination.
9. The method of claim 1 , wherein flotation is performed with solids at between 10% and 40%.
10. The method of claim 1 , wherein the ore sample is subjected to crushing and grinding prior to the combining step.
11. The method of claim 1 , wherein, prior to the combining step, separating the ore sample with a wet high intensity magnetic separator into two groups—a predominantly iron-containing ore and a predominantly ancylite-containing ore; wherein the separator has a grooved plate matrix and applies a magnetic field with a current of between 0.1 and 16 amperes.
12. The method of claim 11 , wherein the separating step is a wet high intensity magnetic separation.
13. A method of increasing the concentration of rare ancylite in an ore sample, the method comprising:
reducing the size of an ancylite containing ore to a particle size of less than about 100 mesh;
passing the particles through a magnetic separator to produce an iron rich sample and an iron reduced sample;
combining the iron reduced sample with a hydroxamic acid collector and one or more additives selected from an ionic compound, a collector, and a frother, wherein the collector includes said hydroxamic acid, to create a slurry;
agitating the slurry;
separating the agitated slurry by flotation into a tailing fraction and a concentrated ancylite float fraction;
collecting the concentrate ancylite fraction to obtain a product ore sample increased concentration of ancylite.
14. The method of claim 13 , wherein the tailing fraction is re-combined with the one or more additives, agitated, and separated to obtain a second concentrated ancylite fraction.
15. The method of claim 13 , wherein the hydroxamic acid is octanohydroxamic acid.
16. The method of claim 15 , wherein the one or more additives include the ionic compound and the ionic compound is strontium nitrate and the frother is AEROFROTH 70.
17. The method of claim 13 , wherein the ancylite concentration of the concentrated ancylite fraction is between about 3% and about 15%.