Concentration process of iron ore slimes

Patent metadata

Field	Value
Publication number	US-11453014-B2
Application number	US-201816753276-A
Country	US
Kind code	B2
Filing date	Oct 3, 2018
Priority date	Oct 6, 2017
Publication date	Sep 27, 2022
Grant date	Sep 27, 2022

Abstract

The present application relates to a concentration process of iron minerals from ultrafine tailings (slimes) from iron ore processing through reverse flotation with pH between 8.5 and 10.5 with the addition of amide-amine type collector, or further a mixture thereof with traditional cationic collectors (amines), in the absence of any depressant, alternatively including a step of high field magnetic concentration, which allows to obtain a concentrate with iron content higher than 66% and contents of SiO2+Al2O3 below 4%.

First claim

The invention claimed is:

1. A process of concentrating iron minerals from ultrafine tailings (slimes) from processing iron ore comprising:
a) adjusting a pH of the slimes to a value in the range of 8.5 to 10.5 by adding a base;
b) adding a collector, wherein the collector comprises an amidoamine cationic collector or a mixture of said amidoamine cationic collector with one or more other collectors, to the slimes and performing conditioning of said collector;
c) adjusting a pulp percent solids by addition of water;
d) performing reverse flotation, in the absence of depressant, to obtain an iron rich concentrate; and
e) a high field wet magnetic concentration step.

2. The process according to claim 1 , wherein the slimes comprise ultrafine particles comprising iron minerals and gangue minerals.

3. The process according to claim 2 , wherein the iron minerals comprise hematite and goethite, and an iron content is 40 to 50%.

4. The process according to claim 2 , wherein the ultrafine particles comprise quartz and kaolinite.

5. The process according to claim 1 , wherein the slimes have 20 to 40% solids.

6. The process according to claim 1 , wherein the base added in step (a) is sodium hydroxide (NaOH).

7. The process according to claim 1 , wherein the amidoamine cationic collector is a straight-chain collector formulated from fatty acids of vegetable origin.

8. The process according to claim 7 , wherein the amidoamine cationic collector comprises N-[3-(Dimethylamino)propyl]dodecanamide as an active molecule.

9. The process according to claim 1 , wherein the one or more other collectors comprise an ether-amine class organic branched-chain cationic collector.

10. The process according to claim 1 , wherein the collector is added in an amount in the range of 50 to 1000 g/t (grams of collector per ton of slimes).

11. The process according to claim 1 , wherein a conditioning time of the collector in step (b) ranges from 10 to 30 minutes.

12. The process according to claim 11 , wherein the conditioning time of the collector in step (b) is 20 minutes.

13. The process according to claim 1 , wherein in step (c) adjusting the pulp percent solids is carried out so that the pulp percent solids is in the range of 15 to 25% solids.

14. The process according to claim 13 , wherein the pulp percent solids is 20% solids.

15. The process according to claim 1 , wherein in step (d), reverse flotation occurs in columns, with addition of water for washing a foam and directing iron minerals to a sunk.

16. The process according to claim 15 , wherein the water is added in an amount which promotes dilution of pulp to a range of 15 to 20% solids.

17. The process according to claim 1 , wherein a residence time of pulp in a column flotation in step (d) is from 20 to 60 minutes.

18. The process according to claim 17 , wherein the residence time is 40 minutes.

19. The process according to claim 1 , wherein a float overflow rate in step (d) is not more than 2 ton/h/m 2 .

20. The process according to claim 1 , wherein the reverse flotation, in step (d), occurs in an open circuit and in one stage.

21. The process according to claim 1 , wherein the reverse flotation, in step (d), occurs in open circuit in more than one stage with a cleaner stage.

22. The process according to claim 1 , wherein in the high field wet magnetic concentration step, a field intensity is from 13,000 to 18,000 Gauss.

23. The process according to claim 1 , wherein magnetic concentration equipment with horizontally or vertically disposed dies, with or without pulsing movement of pulp in a basin, is employed.

24. The process according to claim 1 , wherein dispersing reagents selected from the group consisting of sodium hexametaphosphate and sodium silicate are employed.

25. The process according to claim 1 , wherein colloidal magnetite is employed as a reagent.

26. The process according to claim 1 , wherein an iron concentrate obtained has an iron content above 66% by weight and a SiO 2 +Al 2 O 3 content below 4.0% by weight.

Assignees

• Vale Sa

Inventors

• Pereira Lima Neymayer
• Carlaile Silva Klaydison
• Curi Segato Maurício

Classifications

• B03C1/002

  High gradient magnetic separation (acting directly on the substance being separated B03C1/025; acting on the medium containing the substance being separated B03C1/32) · CPC title

• B03D1/008 Primary

  containing oxygen · CPC title

• B03C2201/20

  Magnetic separation of bulk or dry particles in mixtures · CPC title

• B03D2201/02

  Collectors · CPC title

• B03C1/025

  High gradient magnetic separators · CPC title