Flotation method

Patent metadata

Field	Value
Publication number	US-11247213-B2
Application number	US-201616324660-A
Country	US
Kind code	B2
Filing date	Aug 15, 2016
Priority date	Aug 15, 2016
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

A flotation method for recovering valuable metal containing ore particles from ore particles suspended in slurry is disclosed. In the method, the slurry is treated in an at least one overflow flotation cell and the valuable metal containing ore particles are recovered by conducting the continuous upwards flow of slurry out of the at least one overflow flotation cell as slurry overflow. At least part of the slurry overflow is conducted to a further treatment step in a treatment system.

First claim

The invention claimed is:

1. A flotation method for recovering valuable metal containing ore particles from ore particles suspended in slurry, wherein:
the ore particles are ground in a grinding step,
the ore particles are classified in a classifier from which at least an overflow is conducted as a slurry feed to a treatment system comprising at least two flotation cells of which at least one is an overflow flotation cell operated with constant slurry overflow and with virtually no froth depth or no froth layer,
the slurry is treated in the at least one overflow flotation cell by introducing flotation gas bubbles into the slurry and by creating a continuous upwards flow of slurry in a vertical direction of a first flotation cell of the at least two flotation cells,
at least part of the valuable metal containing ore particles are adhered to the gas bubbles and rise upwards by buoyancy, at least part of the valuable metal containing ore particles are adhered to the gas bubbles and rise upwards with the continuous upwards flow of slurry, and at least part of the valuable metal containing ore particles not adhering to the gas bubbles rise upwards with the continuous upwards flow of slurry,
the valuable metal containing ore particles are recovered by conducting the continuous upwards flow of slurry out of the at least one overflow flotation cell as slurry overflow,
a volumetric flow rate of the slurry overflow is analysed and the flow rate of the slurry feed is controlled so that the constant slurry overflow is generated, and
at least part of the slurry overflow is conducted to a further treatment step in the treatment system.

2. The method according to claim 1 , wherein at least one flotation cell of the at least two flotation cells is a flotation cell operated with conventional froth overflow.

3. The method according to claim 1 , wherein the slurry is agitated mechanically in the flotation cells.

4. The method according to claim 1 , wherein the volumetric flow rate of the slurry overflow is analysed by direct measurement.

5. The method according to claim 1 , wherein the volumetric flow rate of the slurry overflow is analysed by measuring the difference between a volumetric flow rate of the slurry feed and a volumetric flow rate of a tailings flow from the at least one overflow flotation cell.

6. The method according to claim 1 , wherein the further treatment step in the treatment system comprises at least one of the following: a second overflow cell, a flotation cell operated with conventional froth flotation, a flotation cleaner cell operated with conventional froth flotation.

7. The method according to claim 1 , wherein the further treatment step in the treatment system comprises a further grinding step.

8. The method according to claim 1 , wherein the slurry overflow from the at least one overflow flotation cell is conducted to the further step in the treatment system by gravity.

9. The method according to claim 1 , wherein the volume of the at least one overflow flotation cell is at least 300 m3.

10. The method according to claim 9 , wherein the volume of the at least one overflow flotation cell is at least 500 m3.

11. The method according to claim 1 , wherein the diameter of the at least one overflow flotation cell is at least 8 m.

12. The method according to claim 11 , wherein the diameter of the at least one overflow flotation cell is at least 10 m.

13. The method according to claim 1 , wherein the volume of the at least one flotation cell operated with conventional froth flotation is less than 75% of the volume of the at least one overflow flotation cell.

14. The method according to claim 13 , wherein the volume of the at least one flotation cell operated with conventional froth flotation is less than 60% of the volume of the at least one overflow flotation cell.

15. The method according to claim 13 , wherein the volume of the at least one flotation cell operated with conventional froth flotation is less than 10% of the volume of the at least one overflow flotation cell.

16. The method according to claim 1 , wherein a volumetric flow rate of a tailings flow from the at least one overflow flotation cell is regulated by a control valve.

17. The method according to claim 16 , wherein a slurry level within the at least one overflow flotation cell is measured by a level measurement device, and the control valve is adjusted based on the measured slurry level to keep the slurry overflow from the at least one overflow flotation cell at a target level.

18. The method according to claim 16 , wherein the volumetric flow rate of the slurry overflow from the at least one overflow flotation cell is analysed by an analysing device, and the control valve is adjusted based on the analysed volumetric flow rate of the slurry overflow to keep the overflow from the at least one overflow flotation cell at a target level.

19. The method according to claim 18 , wherein the analysing device is an online laser analyser.

20. The method according to claim 1 , wherein, after being ground in a grinding mill, at least 80% of the ore particles have a particle size of less than 650 μm.

21. The method according to claim 20 , wherein, after being ground in the grinding step, at least 80% of the ore particles have a particle size of less than 400 μm.

22. The method according to claim 1 , wherein the amount of solids in the slurry overflow from the at least one overflow flotation cell is at least 20% by weight.

23. The method according to claim 1 , wherein the amount of solids in the slurry overflow from the at least one overflow flotation cell is at least 10% by weight.

24. The method according to claim 1 , wherein the amount of solids in the slurry overflow from the at least one overflow flotation cell is at least 15-55% by weight.

25. The method according to claim 1 , wherein a mass pull of the at least one overflow flotation cell is at least 10%.

26. The method according to claim 25 , wherein the mass pull of the at least one overflow flotation cell is 15-20%.

27. The method according to claim 1 , wherein creating the continuous upwards flow of slurry in the vertical direction of the first flotation cell includes infeeding the slurry into the first flotation cell upwardly.

Assignees

• Outotec Finland Oy

Inventors

• Rinne Antti
• Bourke Peter Gerard

Classifications

• G01F1/661

  using light · CPC title

• B03D2203/025

  Precious metal ores · CPC title

• B02C23/20

  after crushing or disintegrating · CPC title

• B03D1/028 Primary

  Control and monitoring of flotation processes; computer models therefor · CPC title

• G01F1/00

  Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow (measuring a proportion of the volume flow G01F5/00) · CPC title