SE546668C2

SE546668C2 - Method and arrangement for treating fine tailings

Info

Publication number: SE546668C2
Application number: SE2251350A
Authority: SE
Inventors: Jörg Hammerschmidt; Maciej Wrobel; Marcus Runkel; Roberto Valery
Original assignee: Metso Metals Oy
Priority date: 2022-06-17
Filing date: 2022-11-17
Publication date: 2025-01-14
Also published as: EP4540427A1; SE2251350A1; WO2023242465A1; CA3259803A1; PE20251097A1; AU2022464781A1; AU2022464781A2

Abstract

A method for handling fine tailings from mineral treatment processes is disclosed. An arrangement for handling fine tailings from mineral treatment processes is further disclosed.

Claims

1. A method for handling fine tailings from mineral treatment processes comprising roasting tailings material (1) in a first roaster (3) having oxidizing conditions creating a first roaster off-gas comprising dust (5) and a first roaster bed discharge (4), - separating the first roaster off-gas comprising dust (5) in at least one primary cyclone (6) to form. a cyclone overflow (7) and cyclone underflow (8), - roasting the first bed discharge (4) and the cyclone underflow (8) in a second roaster (9) having oxidizing conditions to form a roasted material flow (18), - feeding the cyclone overflow (7) into a heat recovery boiler (10) to form a heat recovery boiler overflow (12) and a heat recovery boiler underflow (11), characterized in that the underflow (11) from the heat recovery boiler (10) is fed into the second roaster (9) and the roasted material flow (18) from the second roaster (9) is fed into a cooler (23) to form a cooler underflow in the form of calcine (22).

2. The method of claim 1, wherein the first roaster lå; is ____ a stationary fluidized bed roaster or a circulating fluidized bed roaster.

3. The method of any of the preceding claims, wherein the second roaster iÉi_is a stationary fluidized bed roaster.

4. The method of any of the preceding claims, wherein the tailings material (lå) has a d50 particle size of 250 pm or less, or 200 pm or less, or 150 pm or less, or 125 pm or less, or 100 pm or less, or 75 pm or less, or 50 pm or less, or 30 pm or less.

5. The method of any of the preceding claims, wherein at least one roasting is performed in an oxygen- enriched atmosphere.

6. The method of any of the preceding claims, wherein the first roaster off-gas comprising dust is separated to form a cyclone overflow iíi_and a cyclone underflow (§)_by _____ passing it through at least two, at least three, at least four, or at least five consecutive primary cyclones Å§) configured to feed the cyclone off- gas from one cyclone into the next cyclone and feeding the cyclone overflow from the final cyclone into the heat recovery boiler (10).

7. The næthod 1*'z\ separated to form a cyclone overflow (/; and a cyclone underflow cyclones ÅÉQ arranged ____ parallel to each other.

8. The method of any of the preceding claims, wherein the first roaster off-gas comprising dust is separated in a separation process comprising using a multiclone.

9. The method of any of the preceding claims, wherein sulfur-containing material contained in the cyclone underflow (8) is granulated and returned (27)

10. The method of any of the preceding claims, wherein the off-gas formed in the one or more cyclones or multiclone is fed into a de-dusting device

11. The method of any of the preceding claims, wherein the off-gas formed in the one or more cyclones, multiclone, and/or de-dusting device ilå) is ____ fed into the first roaster ____ (Ä).

12. The method of any of the preceding claims, wherein sulfur is oxidized in the first and/or second roasting.

13. The method of any of the preceding claims, wherein the heat recovery boiler overflow (12) is fed into a de-dusting device (13) to separate remaining dust (15) from the off-gas (14) and the dust is collected, granulated or pelletized (20), and returned (26) to the first roaster (3).

14. The method of any of the preceding claims, wherein the tailings material (1) comprises tailings formed in a primary flotation treatment (30) of underflow material (31) from a mineral flotation line.

15. The method of claim 14, wherein the primary flotation treatment arranged to receive underflow (31) from a mineral flotation line as slurry infeed, for the separation of slurry into cleaner underflow of recovered valuable material (33) and cleaner overflow (29) arranged to flow into the first roaster (3) as ____ infeed.

16. The method of claim 15, wherein the recovered valuable material comprises iron.

17. The method of claim 14, the primary flotation treatment arranged to receive underflow (31) from a mineral flotation line as slurry infeed, for the separation of slurry into cleaner overflow of recovered valuable material (33) and cleaner underflow (34) arranged to flow into the first roaster i§)_as infeed.

18. The method of claim 17, wherein the recovered valuable material comprises copper.

19. The method of any one of claims 14 - 18, wherein the amount of water in the tailings material ill is reduced using a thickener prior to roasting.

20. The method of any one of claims 14 - 19, wherein the amount of water in the tailings material (1) is reduced by filtering prior to roasting.

21. The method of any one of claims 14 - 20, wherein the amount of water in the tailings material (1) is reduced by filtering using a pressure filter prior to roasting.

22. An arrangement for handling fine tailings from mineral treatment processes whßvacterized in that said arrangement compriseszeempriri ﬁ-Qí - a first roaster (3) configured to roast the fine tailings (1) from the ndneral treatment process to form a first roaster off-gas comprising dust (5) and a first roaster bed discharge (4) and the roaster is configured to feed the first roaster off-gas comprising dust (5) into a primary cyclone (6) and to feed the first roaster bed discharge (4) into a second roaster (9), - at least one primary cyclone (6) configured to receive the first roaster off-gas comprising dust (5) and separating it to form a cyclone overflow (7) and a cyclone underflow (8) and the cyclone is configured to feed the cyclone underflow (8) into a second. roaster (9) and. the cyclone overflow (7) into a heat recovery boiler (10), - a heat recovery boiler (10) configured to receive the cyclone overflow (7) and forming a heat recovery boiler overflow (12) and heat recovery boiler underflow (11) and feeding the heat recovery boiler underflow (11) into a second roaster (9), - a second roaster (9) configured to receive the first roaster bed discharge (4) and cyclone underflow (8), and roasting them to form a roasted material flow (18) and feeding it into a cooler (23), and a cooler (23) configured to receive the roasted material flow (18) and forming a cooler underflow in the form of calcine (22).

23. The arrangement according to claim 22, wherein at least one roaster is an oxidizing roaster.

24. The arrangement according to any one of claims 22 - 23, wherein. all roasters are oxidizing roasters.

25. The arrangement according to any one of claims 22 - 24, wherein. the first roaster* (3) _____ “is a stationary fluidized bed roaster or a circulating fluidized bed roaster.

26. The arrangement according to any one of claims 22 - 25, wherein the second roaster (Q) is _____ a stationary fluidized bed roaster.

27. The arrangement according to any one of claims 22 - 26, wherein the cooler (23) is ____ a fluid bed cooler or a drum cooler.

28. The arrangement according to any one of claims 22 - 27, wherein the arrangement comprises at least two, at least three, at least four, or at least five primary cyclones (Q) arranged ____ consecutively after each other.

29. The arrangement according to any one of claims 22 - 28, wherein the arrangement comprises at least two primary cyclones (5) arranged parallel to each other.

30. The arrangement according to any one of claims 22 - 29, wherein. the primary' cyclone(s) lå) comprises a multiclone.

31. The arrangement according to any one of claims 22 - 30, wherein sulfur is oxidized in the first and/or second roasting.

32. The arrangement according to any one of claims 22 - 31, wherein the arrangement comprises a de- dusting device (13) arranged to receive the heat recovery boiler overflow (12) to separate remaining dust (15) in the recovery boiler overflow from the off-gas (14).

33. The arrangement according to of any one of claims 22 - 32, wherein. the tailings material (lå) comprises tailings formed in a primary flotation treatment (30) of underflow material (3l) from a mineral flotation line.

34. The arrangement according to claim 33, wherein the primary flotation treatment i§QlMis arranged to receive underflow (3l) from a mineral flotation line as slurry infeed, for the separation of slurry into cleaner underflow of recovered valuable material (33) and cleaner overflow (29) arranged to flow into the first roaster (3) as infeed.

35. The arrangement according to of any one of claims 22 - 34, wherein the recovered valuable material Åâåg comprises ____ iron.

36. The arrangement according to claim 33, wherein the primary flotation treatment ¿3§) is arranged to receive underflow (3l) from a mineral flotation line as slurry infeed, for the separation of slurry into cleaner overflow of recovered valuable material (33) and cleaner underflow (34) arranged to flow into the first roaster (3) as ____ infeed.

37. The arrangement according to of any one of claims 22 - 36, wherein the recovered valuable material (33) comprises copper.

38. The arrangement according to of any one of claims 22 - 37, wherein. the mineral flotation line comprises at least three flotation units.