ORE-DRESSING PROCESS

Abstract

This invention applies to the field of ore processing processes aiming to provide a reduction or increase in the concentration of one of its constituents, as well as describes a process to concentrate the lithium oxide content from pegmatite rock from the tailings of heavy mineral gravimetric concentration recovery processes.

Claims

1-14. (canceled)

15. A process for ore processing including Ore milling to ensure proper particle size and Ore size classification for the return of inadequate particles, said process comprising the steps of: desliming pegmatite ore to obtain deslimed material; subjecting said deslimed material to a magnetic separation process including a rougher magnetic separation step followed by a cleaner magnetic separation step to obtain non-magnetic material; and subjecting said non-magnetic material to a flotation process including a rougher flotation step followed by a cleaner flotation step in order to obtain lithium oxide.

16. The process according to claim 15, wherein the desliming step further comprises removing ultrafine particles smaller than 0.038 mm.

17. The process according to claim 15, wherein sludge including tailings are further obtained during the desliming step.

18. The process according to claim 15, wherein minerals containing Fe.sub.2O.sub.3 in their crystalline structure are removed during the magnetic separation process prior.

19. The process according to claim 15, wherein the magnetic separation process removes Fe.sub.2O.sub.3 present in the deslimed material obtained in the desliming step.

20. The process according to claim 15, wherein pH is controlled and pulp is conditioned with a mixture of collecting reagents during the flotation process.

21. The process according to claim 20, wherein said pH is between 6.5 and 7.5.

22. The process according to claim 20, wherein said mixture of collecting reagents comprises fatty acids in concentrations from 150 g/t to 400 g/t, and sodium aliphatic sulfocarboxylate with a carbon chain differentiated from the fatty acids, in concentrations from 50 g/t to 150 g/t.

23. The process according to claim 15, wherein the rougher flotation step and the cleaner flotation step are carried out on mechanical flotation cells.

24. The process according to claim 23, wherein a commercial foaming agent is added to the mechanical flotation cell used during the rougher flotation step.

25. The process according to claim 15, wherein a recycle system is used during the cleaner flotation step for returning tailings present in a cleaner flotation flow back to said rougher flotation step.

26. The process according to claim 15, wherein pegmatite ROM resulting from tailings of a heavy mineral gravimetric concentration process is used as a feed stream for the process.

27. The process according to claim 15, wherein said ore is spodumene.

28. The process according to claim 15, wherein said lithium oxide is obtained in concentrations between 5.5% and 6.5%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0018] This invention describes a process capable of promoting the concentration of lithium oxide in tailings coming from the gravimetric plant and/or from the pegmatite in the mine.

[0019] This process comprises the following stages: milling, classification, desliming, magnetic separation (in two stages) and flotation (in two stages).

[0020] The process is fed with the pegmatite ROM, with the tailings from gravimetric plants and as well as with tailings stored in the dam.

[0021] Initially, the ore is milled to ensure an adequate size for subsequent stages. To ensure that the size of this particle at the milling stage is reached, the classification stage guarantees the size, returning the particles to the milling stage if the classification is negative.

[0022] The pegmatite ore is then submitted to a desliming stage.

[0023] This desliming stage involves the removal of the ultra-fine particles (0,038 mm), which increase the consumption of reagent and reduce the metallurgical recovery of the process.

[0024] This desliming stage can occur in hydro-cyclones or in classification spirals.

[0025] Two flows are obtained from this desliming stage: the sludge and the deslimed material, which is the feed flow of the next stage: magnetic separation.

[0026] The deslimed material follows to the magnetic separation stage, which occurs in two stages, rougher and cleaner, with the purpose of removing contaminants present in the flow resulting from the desliming stage. The magnetic separation stage takes place in two or three stages in order to remove minerals that include Fe.sub.2O.sub.3 in their composition. Magnetic separation occurs in the Rougher/Cleaner or Rougher/Cleaner/Recleaner stages in WHIMS (Wet High Intensity Magnetic Separation) type separators having magnetic fields above 10,000 Gauss.

[0027] From this magnetic separation stage, the magnetic material (tailing) is obtained, which follows on to the tailings thickener and dewatering operation. The non-magnetic flow is directed to the flotation stage.

[0028] The flotation stage comprises regularization, so that the pH remains controlled between 6.5 and 7.5, pulp conditioning with fatty acid and sodium aliphatic sulfocarboxylate with a carbon chain differentiated from the fatty acids as a mixture of collecting reagents, as well as flotation in two stages, rougher and cleaner. As in any concentration operation, for flotation it is also difficult to obtain the desired metallurgical content and recovery in a single stage. In general, a first flotation is performed, called rougher, where a poor concentrate and tailings that still contain useful mineral contents is obtained. The concentrate is washed again in a second flotation, called cleaner, where a final concentrate and low content tailings are produced.

[0029] The flotation stage begins in the conditioning tank, where fatty acids are added, as well as compounds derived from the same, in concentrations between 150 g/t and 400 g/t, in addition to aliphatic sodium disulfocarboxylate in concentrations between 50 g/t and 150 g/. They are intended to increase the flotability of lithium-containing minerals.

[0030] From this conditioning tank, the pulp obtained is sent to the first stage of flotation: Rougher flotation that occurs in mechanical flotation cells.

[0031] In the Rougher flotation stage a commercial foaming agent is added to the feed box of the first mechanical flotation cell.

[0032] The second stage of flotation is the Cleaner flotation, performed by mechanical flotation cells. The tailings from the Cleaner flotation flow back into the Rougher flotation feed.

[0033] The final concentrate obtained from the flotation stages goes on to the filtering stage, with a humidity of 10%.

[0034] After this filtering stage, the concentrate goes on to the drying stage, where a product with a humidity of up to 2% is obtained.

[0035] The concentrate conveying system comprises pneumatic pumps, silos, filters and a bagging station.

[0036] The pneumatic pump of the conveying system sends the concentrate to the feed silo, which transports the concentrate to one of the four quality control silos.

[0037] The quality control silos have a volume of 50 m.sup.3.

[0038] The quality control silos can store the product for approximately six hours at nominal feed rates. From these quality control silos, the product is transported to one of the four storage silos.

[0039] The choice of receiving silos is based on the quality of the product. These receiving silos have a volume of 200 m.sup.3.

[0040] The blending silo has a pneumatic pump, capable of pumping the concentrate into the bagging system.

[0041] In this packing system, the final product is packed in Big Bags of approximately one and a half tons, and then transported and stored for 24 days.

[0042] The present invention has been disclosed in this description in terms of its preferred embodiment. However, other modifications and variations are possible based on this description, and are still inserted within the scope of the invention revealed herein.