Flotation line and a method

Abstract

A flotation line for treating mineral ore particles suspended in slurry, including at least three flotation units arranged in fluid connection with each other for allowing gravity-driven slurry flow between flotation units, and a feed inlet for supplying slurry into a first flotation unit; wherein at least three flotation units are configured to be uniplanar, each flotation unit includes at least one flotation cell; and wherein the launder lip height of each uniplanar flotation unit is lower than the launder lip height of the preceding uniplanar flotation unit in the direction of the slurry flow, so that an angle of sloping between a first uniplanar flotation cell, equipped with a launder lip and being larger than 150 m.sup.3, and a last uniplanar flotation cell, equipped with a launder lip and being larger than 40 m.sup.3, is formed; and the angle is 1.5 to 10 degrees relative to horizontal.

Claims

1. A flotation line for treating mineral ore particles suspended in slurry, the flotation line comprising: at least three flotation units arranged in fluid connection with each other for allowing gravity-driven slurry flow between the at least three flotation units, each flotation unit of the at least three flotation units including at least one flotation cell, so that each flotation unit includes at least one flotation cell equipped with a launder lip, at least one flotation cell equipped with a mixing apparatus, and at least one flotation cell equipped with a dispersed gas feeding mechanism; and a feed inlet for supplying slurry into a first flotation unit of the at least three flotation units, wherein: the at least three flotation units are configured to be uniplanar, so that bottoms of the at least three flotation units are positioned at least partially within a vertical range measured from a level of a bottom of a first flotation cell equipped with a launder lip and being larger than 150 m.sup.3, wherein the vertical range is defined as a distance between a first line drawn at an angle of +1° relative to horizontal and a second line drawn at an angle of −0.1° relative to horizontal, the first and second lines starting from a lowest functional position of the bottom of the first flotation cell; each flotation cell equipped with a launder lip comprises a slurry inlet, a tailings outlet, and a concentrate outlet; a flotation unit launder lip height of each uniplanar flotation unit is lower than a flotation unit launder lip height of a preceding uniplanar flotation unit in a direction of a slurry flow, the flotation unit launder lip height determined by the launder lip of a flotation cell of a respective flotation unit, measured from a same position for each flotation unit of the flotation line, so that an angle of sloping between a horizontal line drawn through a launder lip height of a first uniplanar flotation cell and a line drawn from a point of a first uniplanar flotation cell, equipped with a launder lip and being larger than 150 m.sup.3, and a corresponding point of a last uniplanar flotation cell, equipped with a launder lip and being larger than 40 m.sup.3, is formed; and the angle of sloping is 1.5 to 10 degrees relative to horizontal, the angle being calculated via corresponding positions of launder lip heights of the first uniplanar flotation cell and the last uniplanar flotation cell.

2. The flotation line according to claim 1, wherein the angle of sloping is 2 to 6 degrees.

3. The flotation line according to claim 1, wherein the angle of sloping is calculated from a center of a launder lip plane of said flotation cells.

4. The flotation line according to claim 1, wherein at least 80% of a volume of uniplanar flotation cells comprising a mixing apparatus is configured to be mixed by a mechanical agitator.

5. The flotation line according to claim 1, wherein a given uniplanar flotation cell is equipped with a launder lip, a mixing apparatus, and a dispersed gas feeding mechanism.

6. The flotation line according to claim 1, wherein the tailings outlet of a uniplanar flotation cell equipped with a launder lip is connected to a slurry inlet of a subsequent uniplanar flotation cell equipped with a mixing apparatus.

7. The flotation line according to claim 1, wherein the flotation unit launder lip height of each uniplanar flotation unit is at least 400 mm lower than the flotation unit launder lip height of the preceding uniplanar flotation unit.

8. The flotation line according to claim 1, wherein flotation cells that comprise at least 80% of a uniplanar flotation cell volume have a launder lip height-to-cell diameter ratio of less than 1.2.

9. The flotation line according to claim 1, wherein flotation cells that comprise at least 80% of a uniplanar flotation cell volume have a launder lip height-to-cell diameter ratio of less than 1.0.

10. The flotation line according to claim 1, wherein flotation cells that comprise at least 80% of a uniplanar flotation cell volume have a launder lip height-to-cell diameter ratio of less than 0.4 to 0.9.

11. The flotation line according to claim 1, wherein the uniplanar flotation cells that comprise a launder lip and are larger than 150 m.sup.3, have a launder lip height-to-cell diameter ratio of less than 1.2.

12. The flotation line according to claim 1, wherein the uniplanar flotation cells that comprise a launder lip and are larger than 150 m.sup.3 have a launder lip height-to-cell diameter ratio of less than 1.0.

13. The flotation line according to claim 1, wherein the uniplanar flotation cells that comprise a launder lip and are larger than 150 m.sup.3 have a launder lip height-to-cell diameter ratio of less than 0.4 to 0.9.

14. The flotation line according to claim 1, wherein a size of at least one uniplanar flotation cell equipped with a launder lip is at least 400 m.sup.3.

15. The flotation line according to claim 1, wherein a size of the first uniplanar flotation cell, equipped with a launder lip, is at least 400 m.sup.3.

16. The flotation line according to claim 1, wherein the at least one flotation cell of a second uniplanar flotation unit in the direction of the slurry flow is smaller than the at least one flotation cell of the first uniplanar flotation unit.

17. The flotation line according to claim 1, wherein the at least one flotation cell of a second uniplanar flotation unit is at least 10% smaller than the at least one flotation cell of the first uniplanar flotation unit.

18. The flotation line according to claim 1, wherein the at least one flotation cell of a third uniplanar flotation unit in the direction of the slurry flow is at least 30% smaller than the at least one flotation cell of the first uniplanar flotation unit.

19. The flotation line according to claim 1, wherein the launder lip height of the first flotation cell, equipped with a launder lip, is at least 6 m.

20. The flotation line according to claim 1, wherein a fluid connection is a direct connection between an outlet of a preceding uniplanar flotation unit and an inlet of a subsequent uniplanar flotation unit in the direction of the slurry flow.

21. The flotation line according to claim 1, wherein fluid connections between uniplanar flotation units larger than 40 m.sup.3 are uniplanar.

22. The flotation line according to claim 1, wherein the at least one flotation cell in a uniplanar flotation unit is a froth flotation cell.

23. The flotation line according to claim 1, wherein the flotation line comprises three to ten uniplanar flotation units larger than 40 m.sup.3.

24. The flotation line according to claim 1, wherein the flotation line comprises four to seven uniplanar flotation units larger than 40 m.sup.3.

25. The flotation line according to claim 1, wherein the flotation line comprises three to ten uniplanar flotation cells larger than 40 m.sup.3.

26. The flotation line according to claim 1, wherein the flotation line comprises four to seven uniplanar flotation cells larger than 40 m.sup.3.

27. The flotation line according to claim 1, wherein at least 80% of the uniplanar flotation cells have a diameter of at least 3.5 m.

28. The flotation line according to claim 1, wherein at least 80% of the uniplanar flotation cells have a diameter of at least 6 m.

29. The flotation line according to claim 1, wherein at least 80% of the uniplanar flotation cells have a diameter of 3.5 to 25 m.

30. The flotation line according to claim 1, wherein at least 80% of the uniplanar flotation cells have a diameter of 6 to 20 m.

31. The flotation line according to claim 1, wherein at least 80% of a volume of third and further uniplanar flotation units is formed of flotation cells whose diameter is at least 0.4 times a diameter of an average of the uniplanar flotation cells in a second uniplanar flotation unit.

32. The flotation line according to claim 1, wherein at least 80% of a volume of third and further uniplanar flotation units is formed of flotation cells whose diameter is at least 0.8 to 1.2 times a diameter of an average of the uniplanar flotation cells in a second uniplanar flotation unit.

33. A flotation method for treating mineral ore particles suspended in slurry in a flotation line according to claim 1, the method comprising: introducing slurry into the flotation line; treating the slurry in the flotation cells of the flotation units for at least partial recovery of valuable metal containing particles from the slurry; leading the slurry to pass from a preceding flotation unit to a successive flotation unit via a fluid connection; and removing tailings from the flotation line though a tailings outlet of a last flotation unit of the flotation line.

34. The flotation method according to claim 33, wherein the method further comprises arranging a conditioner upstream of the first uniplanar flotation cell, and treating the slurry in the conditioner prior to introducing into the flotation line.

35. The flotation method according to claim 33, wherein density of the slurry to be treated is 1.1 to 1.7 t/m.sup.3.

36. The flotation method according to claim 33, wherein the slurry comprises mineral ore particles having a P80 of 10 to 2,000 μm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are included to provide further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention.

(2) In the drawings:

(3) FIG. 1 is a schematic presentation of an exemplary embodiment of the flotation line according to the current disclosure.

(4) FIG. 2 is a schematic presentation of another exemplary embodiment of the flotation line according to the current disclosure.

(5) FIG. 3 is a schematic presentation of yet another exemplary embodiment of the flotation line according to the current disclosure.

(6) FIG. 4 is a schematic presentation of yet another exemplary embodiment of the flotation line according to the current disclosure.

(7) FIGS. 5a, 5b, 5c and 5d are a schematic presentation of exemplary horizontal arrangements of the flotation line according to the current disclosure.

(8) FIGS. 6a, 6b, 6c, 6d, and 6e are a schematic presentation of exemplary vertical arrangements of the flotation line according to the current disclosure.

DETAILED DESCRIPTION OF THE INVENTION

(9) Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

(10) Although flotation is disclosed in the following examples by reference to froth flotation, it should be noted that the principles according to the invention can be implemented regardless of the specific type of the flotation, i.e. the flotation technique can be any of the known per se flotation techniques, such as froth flotation, dissolved air flotation or induced gas flotation.

(11) FIGS. 1-4 illustrate a flotation line 1 in a schematic manner. The figures are not drawn to proportion, and many of the components of the flotation line 1 are omitted for clarity. The direction of slurry flow is depicted in each of FIGS. 1 to 4 by an arrow and a text “flow”.

(12) In the embodiment of FIG. 1, the flotation line 1 comprises four uniplanar flotation units 2, defining a length L for the uniplanar flotation line. A conditioner tank 10 is depicted in FIG. 1, and other pre-treatment devices relating to earlier process phases, such as diminution, grinding, classification, may be present. Also further flotation units, which are not uniplanar, may be present. The additional devices may be positioned before, after or between the uniplanar flotation units 2.

(13) The conditioner tank 10 is connected to the first uniplanar flotation cell 20 by a feed inlet 11 and a cell inlet 31. The uniplanar flotation cells 20, 21, 22, 23 are connected to each other by fluid connections 3. In FIG. 1, the fluid connection between the flotation cells 20 and 21 is formed as a piping, since the two flotation cells are positioned at a distance D from each other. The slurry flows through cell outlet 32 of flotation cell 20 to the cell inlet 31 of flotation cell 21. A corresponding system is arranged between flotation cells 22 and 23, since also they are separated from each other by a distance D. In contrast, the flotation cells 21 and 22 are connected by a direct connection 33, as the flotation cells 21, 22 are right next to each other. The tailings exit the flotation line 1 through a tailings outlet 7. All details and components of the fluid connections between the flotation cells 20, 21, 22, 23 are omitted.

(14) In the embodiment of FIG. 1, the bottoms 4 of all the uniplanar flotation cells 20, 21, 22, 23 are on the same vertical level. Thus, all the uniplanar flotation cells 20, 21, 22, 23 are uniplanar.

(15) Each uniplanar floatation cell 20, 21, 22, 23 comprises a mixing apparatus comprising a shaft 9 and a dispersed gas feeding mechanism 91. The shaft is positioned along the vertical centerline of the flotation cell 20, 21, 22, 23 diameter. In the flotation cell 20, the dispersed gas feeding mechanism 91 is located at the side of the shaft, whereas in the flotation cells 21, 22, 23, the dispersed gas feeding mechanism 91 is concentric with the shaft 9. The skilled person is able to select a suitable dispersed gas feeding mechanism according to the specifics of the embodiment. The size of the dispersed gas feeding mechanism may vary.

(16) Each uniplanar flotation cell 20, 21, 22, 23 comprises an overflow launder 5, which again comprises a launder lip 51, at a height h.sub.20, h.sub.21, h.sub.22, h.sub.23, from the bottom 4. The launder lip 51 determines the launder lip height H.sub.20, H.sub.21, H.sub.22, H.sub.23, which is the highest for the first uniplanar flotation unit 2, and decreases for every subsequent uniplanar flotation unit 2 in the direction of the slurry flow. The flotation unit launder lip height H may be calculated from the lowest uniplanar flotation cell in the flotation line, or from any other suitable height, as long as it is done consistently throughout the flotation line. The flotation unit launder lip height H allows the determination of an angle β.

(17) Each flotation cell 20, 21, 22, 23 has a diameter d.sub.20, d.sub.21, d.sub.22, d.sub.23. By the diameter d.sub.20, d.sub.21, d.sub.22, d.sub.23 is herein meant the average inside diameter of the uniplanar flotation cell 20, 21, 22, 23 between the lowest functional position of the bottom 4, and the launder lip 51. This diameter d can be used for determining the effective volume of the flotation cell 20, 21, 22, 23. The center of the uniplanar flotation cell 20, 21, 22, 23 on the launder lip height 8 may be used for calculating the angle β, as was done in the embodiment of FIG. 1, as well as for determining the uniplanarity of a given flotation cell 20, 21, 22, 23. The determination of the angle β is depicted by line A traversing the centers of the first uniplanar flotation cell 20 and the last uniplanar flotation cell 23 at the height of the launder lip 51.

(18) The diameter d of the uniplanar flotation cells 20, 21, 22, 23 decreases in the direction of the slurry flow.

(19) Table 1 describes the dimensions of the flotation line presented in FIG. 1. As depicted in table 1, the volume of the first uniplanar flotation cell 20 is 630 m.sup.3 and the volume of the second uniplanar flotation cell 21 is 200 m.sup.3. The volume of the third uniplanar flotation cell 22 is 130 m.sup.3 and the volume of the fourth uniplanar flotation cell 23 is 70 m.sup.3.

(20) The value given in the height column in table 1, and in all the following tables, refers to the launder lip height h.sub.20, h.sub.21, h.sub.22, h.sub.23 of the uniplanar flotation cell 20, 21, 22, 23, as measured from the flotation cell bottom 4 to the launder lip 51. The value given in the diameter column refers to the diameter d.sub.20, d.sub.21, d.sub.22, d.sub.23 of the uniplanar flotation cell 20, 21, 22, 23. Drop is the change in launder lip height H between two subsequent uniplanar flotation units 2.

(21) The launder lip height of the uniplanar flotation cells 20, 21, 22, 23 gradually decreases along the flotation line 1 in the direction of the slurry flow. The launder lip height 51 of the first uniplanar flotation cell 20 is 7 m, whereas that of the second uniplanar flotation cell 21 is 5.4 m, the drop thus being 1.6 m. The launder lip height 51 of the third uniplanar flotation cell 22 is 4.7 m, resulting in a drop of 0.7 m. The launder lip height 51 of the fourth uniplanar flotation cell 23 is 3.5 m, i.e. 1.2 m less than for the previous flotation cell. The diameter of the uniplanar flotation cells 20, 21, 22, 23 is 11 m for the first, 7.2 for the second, 6.4 for the third, and 5.3 for the third flotation cell.

(22) An angle of launder lip height drop over the whole of the length L of the uniplanar flotation line 1 is defined as the angle β, calculated over the entire uniplanar flotation line length, i.e. the length the slurry flow travels over the flotation line from the feed inlet 11 to the tailings outlet 7. Angle β is, in this example, the angle between the launder lip height H.sub.20 of the first uniplanar flotation cell 20, and the line A traversing the center of the uniplanar flotation cell 20 cross section at the launder lip 51 height, and the corresponding position (i.e center of the flotation cell cross section at launder lip level) at the fourth uniplanar flotation cell 23. The angle β of the uniplanar flotation line 1 in this example is approximately 6°.

(23) TABLE-US-00001 TABLE 1 Dimensions of the uniplanar flotation line 1 in FIG. 1. Flotation Vol. H, d, D, Drop, cell m.sup.3 mm mm mm mm 1 (20) 630 7,000 11,000 — — 2 (21) 200 5,400 7,200 5,900 1,600 3 (22) 130 4,700 6,400 500 700 4 (23) 70 3,500 5,300 4,000 1,200 Sum 29,900 10,400 3,500

(24) In the embodiment of FIG. 1, the length of the uniplanar flotation line is thus the sum of all flotation cell diameters (29,900 mm) and the distances between the flotation cells (10,400 mm), i.e. 40,300 mm (40.3 m). In this, and in all the following examples, a distance of 500 mm is calculated for the machinery needed to regulate the slurry flow between the flotation cells that are directly next to each other. As the decrease in the flotation unit launder lip height H (drop) is 3,500 mm (3.5 m), the angle β is 5°.

(25) The slurry is conducted to the uniplanar flotation line 1 by leading it through a feed inlet 11 connected to the cell inlet 31 of the first uniplanar flotation unit 2 of the flotation line 1. The slurry is allowed to flow through the flotation line 1 via the fluid connections 3, 33. The tailings from the last uniplanar flotation unit 2 of the flotation line 1 are lead out of the flotation line 1 via a tailings outlet 7 and may be further treated in conventional manner.

(26) The embodiment of FIG. 2 resembles that of FIG. 1, so not all features presented for FIG. 1 are repeated. The embodiment comprises three uniplanar flotation units 2, the first of which comprises one flotation cell 20. The second and third uniplanar flotation units 2 comprise two flotation cells 21a, 21b, 22a, 22b each. In FIG. 2, the bottoms 4 of all uniplanar flotation cells 20, 21a, 21b, 22a, 22b are positioned on the same vertical level.

(27) Each uniplanar flotation unit 2 has its launder lip height H.sub.20, H.sub.21, H.sub.22. The flotation cell launder lip height h of the two flotation cells 21a, 21b and 22a, 22b in each uniplanar flotation unit 2 is equal. However, if the bottoms 4 of the two flotation cells 21a, 21b, 22a, 22b in one uniplanar flotation unit were on different levels, the launder lip height h for these flotation cells 21a and 21b, 22a and 22b would be different, so that the launder lip height H of the uniplanar flotation unit 2 remains unambiguous.

(28) All the uniplanar flotation cells 20, 21a, 21b, 22a, 22b are connected through direct connections 33. Thus, the flotation cells 20, 21a, 21b, 22a, 22b are separated from each other by a minimal distance due to the space taken by the direct connection 33 arrangement.

(29) The dimensions of the flotation line 1 depicted in FIG. 2 are given in table 2. The volume of the first uniplanar flotation cell 20, forming the first uniplanar flotation unit 2, is 380 m.sup.3. The volume of each flotation cell 21a, 21b in the second uniplanar flotation unit 2 is 340 m.sup.3, whereas the volume of the flotation cells 22a, 22b in the third uniplanar flotation unit is 300 m.sup.3. The launder lip height H.sub.20 of the first uniplanar flotation unit 2 is 8.61 m. The launder lip height H.sub.21 of the second uniplanar flotation unit 2 is 0.8 m lower, i.e. 7.81 m. A reduction in launder lip height of 0.71 m, to 7.1 m takes place between the second and third uniplanar flotation unit 2.

(30) In the embodiment of FIG. 2, the diameter of the uniplanar flotation cells remains constant, at 8 m.

(31) TABLE-US-00002 TABLE 2 Dimensions of the flotation line 1 in FIG. 2. Flotation Vol. , H, d, D, Drop, cell m.sup.3 mm mm mm mm 1 (20) 380 8,610 8,000 — — 2 (21a) 340 7,810 8,000 500 800 2 (21b) 340 7,810 8,000 500 — 3 (22a) 300 7,100 8,000 500 710 3 (22b) 300 7,100 8,000 500 — Sum 40,000 2,000 1,510

(32) In the embodiment of FIG. 2, the length of the uniplanar flotation line is thus the sum of all flotation cell diameters (40,000 mm) and the distances between the flotation cells (2,000 mm), i.e. 42,000 mm (42.0 m). As the decrease in the flotation unit launder lip height H (drop) is 1,510 mm (1.51 m), the angle β is 2°.

(33) The angle of launder lip height reduction over the whole of the length L of the uniplanar flotation line 1 is defined as the angle β, calculated over the entire uniplanar flotation line length L, i.e. the length the slurry flow travels over the flotation line from the feed inlet 11 of the first uniplanar flotation cell 20 to the tailings outlet 7 of the last uniplanar flotation cell 22b. Angle β is, in this embodiment, the angle between the launder lip height H.sub.20 of the first flotation cell 20, and the line A traversing the center 8 of the first uniplanar flotation cell 20 at the launder lip 51 height, and the corresponding position of the last uniplanar flotation cell 22b.

(34) The embodiment of FIG. 3 resembles those of the previous figures. A conditioner tank 10 has been included in the drawing. The embodiment comprises four uniplanar flotation units 2, all of which comprise one flotation cell 20, 21, 22, 23. The fluid connections between the first two uniplanar flotation cells 20, 21, and between the two last uniplanar flotation cells, 22, 23, are arranged as a direct connections 33. The connection between the second and third uniplanar flotation cell 21, 22 comprises piping, and the two uniplanar flotation cells are separated by a distance D.

(35) In Table 3, dimensions of the uniplanar flotation units 2 are given for the flotation line 1 of FIG. 3. The volume of the first uniplanar flotation cell 20 is 630 m.sup.3, and the volume of the subsequent uniplanar flotation cells 21, 22, 23 decreases to 200 m.sup.3, 130 m.sup.3 and to 70 m.sup.3. At the same time, the launder lip height 51 decreases from 6.6 m for the first uniplanar flotation cell 20 to 5.4 m for the second, to 4.7 for the third and to 3.7 for the fourth uniplanar flotation cell 21, 22, 23, respectively. Thus, the first decrease in launder lip height 51 is 1.2 m, the second 0.7 m and the third 1.0 m. The diameter of the uniplanar flotation cells also decreases from 11.0 m for the first uniplanar flotation cell, through 7.2 m and 6.4 m for the second and third, to 5.3 m for the fourth uniplanar flotation cell 23.

(36) TABLE-US-00003 TABLE 3 Dimensions of the flotation line 1 in FIG. 3. Flotation Vol. , H, d, D, Drop, cell m.sup.3 mm mm mm mm 1 (20) 630 6,600 11,000 — — 2 (21) 200 5,400 7,200 500 1,200 3 (22) 130 4,700 6,400 8,000 700 4 (23) 70 3,700 5,300 500 1,000 sum 29,900 9,000 2,900

(37) In the embodiment of FIG. 3, the length of the uniplanar flotation line is thus the sum of all flotation cell diameters (29,900 mm) and the distances between the flotation cells (9,000 mm), i.e. 38,900 mm (38.9 m). As the decrease in the flotation unit launder lip height H (drop) is 2,900 mm (2.9 m), the angle β is 4.3°.

(38) In the embodiment of FIG. 4, the flotation line comprises four uniplanar flotation units 2, each comprising one flotation cell 20, 21, 22, 23. All the flotation units 2 are connected through piping 3, which is of different length between every flotation unit 2, reflecting the difference in the distance D between the flotation units 2.

(39) In Table 4, dimensions of uniplanar flotation units 2 for the embodiment in FIG. 4 are given. The volume of the first uniplanar flotation cell 20 is 775 m.sup.3 and that of the second 21 is 630 m.sup.3. The volume of the third uniplanar flotation cell 22 is 200 m.sup.3 and that of the fourth 23 is 70 m.sup.3. The diameter of the first two uniplanar flotation cells 20, 12 is 11 m, the diameter of the third uniplanar flotation cell 22 is 7.2 m, and the diameter of the fourth uniplanar flotation cell is 5.3 m.

(40) The launder lip 51 height h.sub.20 of the first uniplanar flotation cell 20 is 8.91 m, and that h.sub.21 of the second uniplanar flotation cell 21 is 7.0 m, with a reduction in height being 1.91 m. The launder lip 51 height h.sub.22 of the third uniplanar flotation cell 22 is 5.4 m, with a 1.6 m reduction in height. The fourth uniplanar flotation cell 23 has a launder lip 51 height h.sub.23 of 3.5 m, with a reduction of 1.9 m to the previous flotation cell.

(41) TABLE-US-00004 TABLE 4 Dimensions of the flotation line 1 in FIG. 4. Flotation Vol. , H, d, D, Drop, cell m.sup.3 mm mm mm mm 1 (20) 775 8,910 11,000 — — 2 (21) 630 7,000 11,000 3,900 1,910 3 (22) 200 5,400 7,200 6,800 1,600 4 (23) 70 3,500 5,300 10,700 1,900 Sum 34,500 21,400 5,410

(42) In the embodiment of FIG. 4, the length of the uniplanar flotation line is thus the sum of all flotation cell diameters (34,500 mm) and the distances between the flotation cells (21,400 mm), i.e. 55,900 mm (55.9 m). As the decrease in the flotation unit launder lip height H (drop) is 5,410 mm (5.41 m), the angle β is 5.5°.

(43) FIG. 5, panels a to d, illustrates various exemplary horizontal arrangements of a flotation line 1. Only the cross-sectional outline of the flotation cells 20, 21, 22, 23 is depicted. Although not directly visible in FIG. 5, all the flotation cells in the figure are uniplanar, as they are used for calculating the length L. Further, in FIG. 5, all flotation cells 20, 21, 22, 23 are considered to comprise a launder lip 51, making it irrelevant for the calculation of length L how the flotation cells 20, 21, 22, 23 are arranged into flotation units 2.

(44) In panel 5a, the flotation cells 20, 21, 22, 23 are organized in a straight line, and each fluid connection is formed as a direct connection 33.

(45) In panel 5b, the flotation cells 20, 21, 22, 23 are organized in a straight line, and each fluid connection is formed as a fluid connection 3 comprising piping. The flotation cells 20, 21, 22, 23 are spaced apart by a distance D, which is the longest between flotation cells 20 and 21. However, it would be possible that the distance D between all flotation cells 20, 21, 22, 23 would be equal.

(46) In the embodiment of panel 5b, the diameter of the flotation cells 20, 21, 22, 23 varies, so that the third uniplanar flotation cell 22 has the largest diameter.

(47) In the embodiment of panels 5c and 5d, the flotation cells 20, 21, 22, 23 are arranged in a curved manner. Such an arrangement may be advantageous, for example, due to the contours of the terrain at the site of installation. The length L is calculated by, starting from the feed inlet 11 and ending to the tailings outlet 7, drawing a line between the cell inlet 31 and the cell outlet 32 through the center of the flotation cell 20, 21, 22, 23.

(48) In panel 5c, the flotation cells 20, 21, 22, 23 are connected by direct connections 33, whereas in panel 5d, the fluid connections 3 comprise piping. The distance D between the flotation cells varies in panel 5d. Also in the embodiments of panels 5c and 5d, it would be possible for the diameters d of the flotation cells 20, 21, 22, 23 to vary, but they are drawn to even size for simplicity.

(49) FIG. 6, panels a to e, illustrates various exemplary vertical arrangements of a flotation line 1. Only the vertical outline of the uniplanar flotation cells 20, 21, 22, 23 is depicted. The fluid connections 3 between the flotation cells 20, 21, 22a, 22b are not detailed in FIG. 6.

(50) The determination of a vertical uniplanarity range U is depicted in FIG. 6. An angle of +/− 1° relative to horizontal is used for drawing two lines B, B′ starting from the lowest functional position of the bottom 4 of the first flotation cell 20 being larger than 150 m.sup.3, equipped with a launder lip 51. The first line B is drawn as ascending B, and the second line B′ as descending. The distance of the lines B, B′ from each other at the vertical line traversing the lowest functional position of the bottom 4 of the last flotation cell 22b, equipped with a launder lip 51, and being larger than 40 m.sup.3, gives the vertical uniplanarity range U. All flotation cells 21, 22a between the flotation cells used for determining the uniplanarity range, whose bottom 4 is within the range U are considered uniplanar, with the further condition that the launder lip height H for the flotation units 2 decreases for each subsequent flotation unit 2 in the direction of slurry flow.

(51) The determination of the angle β is also illustrated in FIG. 6. In panels 6a, 6b, 6d and 6f, the center of the first flotation cell 20 being larger than 150 m.sup.3, equipped with a launder lip 51, at the launder lip 51 height h.sub.20, and the center of the last flotation cell 22b or 22, equipped with a launder lip 51, and being larger than 40 m.sup.3 is used for drawing a line A traversing these points. The angle between A and horizontal (illustrated by launder lip height H.sub.20 of the first flotation unit 2) determines an angle β.

(52) In panels 6c and 6e, other corresponding points on the circumference in the direction of the flotation line length on the launder lip level of the flotation cell are used. In panel 6c, the first point on the circumference of each flotation cell 20 and 22 in the direction of slurry flow is used. In panel 6e, the last point on the circumference of each flotation cell 20 and 22b in the direction of slurry flow is used.

(53) In panel 6a, the flotation line 1 comprises four uniplanar flotation cells 20, 21, 22a, 22b, arranged in three flotation units 2. The first two flotation units 2 comprise one uniplanar flotation cell 20, 21 each, i.e. the flotation cell 20, 21 comprises a launder lip, a mixing apparatus and a dispersed gas feeding mechanism (not shown). The third uniplanar flotation unit 2 comprises two uniplanar flotation cells 22a, 22b. The flotation line 1 further comprises a pre-treatment device 10, which may be a conditioner tank or a flotation cell, for example. In the embodiment of panel 6a, all the flotation cells 20, 21, 22, 23 are horizontal.

(54) In panel 6b, the flotation line 1 comprises five uniplanar flotation cells 20a, 20b, 21, 22a, 22b, arranged in three flotation units 2. The flotation cells 20a, 20b, 22a, 22b forming the first and third flotation units 2, respectively, are horizontal. However, the bottom 4 of the flotation cell 21 forming the second flotation unit 2 is higher than the in the other flotation cells 20a, 20b, 22a, 22b, but within the vertical uniplanarity range U. As the launder lip height H of the flotation units decreases, and the sizes of the flotation cells fall within the determined range, the flotation cells 20a, 20b, 21, 22a, 22b are uniplanar.

(55) In the embodiment of panel 6c, the flotation line 1 comprises four flotation cells 20, 21, 22, 10. Of the three uniplanar flotation cells 20, 21, 22, each of which forms a flotation unit 2, the bottoms 4 of the first and third 20, 22 are horizontal. The bottom 4 of the second uniplanar flotation cell 21 is lower than that of the neighboring ones, but within the uniplanarity range U, and the launder lip 51 height of the flotation cells 20, 21, 22 decreases. Also the bottom 4 of the last flotation cell 10 in the direction of slurry flow is within range U, but its volume is less than 40 m.sup.3, and it is thus not included in the uniplanar flotation line.

(56) In the embodiment of panel 6c, there is one flotation cell 10 at the end of the flotation line 1, which is not included in the determination of the angle β. However, it would be possible that one or both ends of the flotation line 1 would have more than one additional flotation cell 10. Further, it is possible that there would be other tanks 10 for various additional flotation-related processes in these positions.

(57) In panel 6d, the flotation line 1 comprises three uniplanar flotation cells 20, 21, 22 and each of them forms a uniplanar flotation unit 2. The bottoms 4 of the uniplanar flotation units 2 are at the same vertical level (i.e. horizontal). The flotation line 1 further comprises a small further tank 10, which may be a flotation cell or a tank of other type. Since it is smaller than 150 m.sup.3, it is not considered uniplanar, and not included in the calculation of the angle β. The flotation line 1 also comprises two flotation cells 10 downstream of the uniplanar flotation units 20, 21, 22. Although they are larger than 40 m.sup.3, they are not within the uniplanarity range, and thus are not considered for the calculation of the angle β.

(58) In panel 6e, the flotation line 1 comprises six flotation cells 10, 20, 21a, 21b, 22a, 22b, whose bottoms 4 are all horizontal. The first flotation cell 10 has a size of less than 150 m.sup.3, and it is thus not considered a uniplanar flotation cell. The first uniplanar flotation cell 20 is the second flotation cell in the flotation line 1, and it forms a flotation unit 2. The third and fourth flotation cell 21a, 21b form one flotation unit 2, as do the fifth and sixth flotation cell 22a, 22b, respectively. The two last flotation units differ from the previous ones in that the first cell of each flotation unit 21, 22 comprises a mixing apparatus and/or a dispersed gas feeding mechanism, but no launder lip (not depicted). Thus, the flotation cell according to which the launder lip height of the flotation unit 2 is calculated is the second flotation cell 21b, 22b of each flotation unit 2.

FURTHER EXAMPLES

(59) In an embodiment of the flotation line 1, the flotation line 1 comprises four flotation units 2, whose dimensions are given in Table 5. The first and third flotation units comprise one flotation cell 20, 22, and the second and fourth flotation units both comprise two flotation cells 21a, 21b and 23a, 23b, respectively. The flotation cells are arranged in direct fluid connection 33 with each other. Thus, the distance D between each two adjacent flotation units 2 is approximated to be 500 mm.

(60) TABLE-US-00005 TABLE 5 Dimensions of a further embodiment of the flotation line 1 according to the current disclosure. Flotation Vol. , H, d, Drop, cell m.sup.3 mm mm mm 1 (20) 630 7,000 11,000 — 2 (21a) 200 5,400 7,200 1,600 2 (21b) 200 5,400 7,200 0 3 (22) 130 4,700 6,400 800 4 (23a) 70 3,700 5,300 1,100 4 (23b) 70 3,700 5,300 0 Sum 42,400 3,500

(61) In the embodiment presented in table 5, the length of the uniplanar flotation line is thus the sum of all flotation cell diameters (42,400 mm) and the distances between the flotation cells (5×500 mm=2,500 mm), totaling 44,900 mm (44.9 m). As the decrease in the flotation unit launder lip height H (drop) is 3,500 mm (3.5 m), the angle β is 4.5°.

(62) In yet another embodiment, the flotation line 1 comprises three flotation units 2, whose dimensions are given in Table 6. All of the flotation units 2 comprise two flotation cells 20a, 20b; 21a, 21b; and 22a, 22b, respectively. The flotation cells 2 are arranged in direct fluid connection 33 with each other. Thus, the distance D between all adjacent flotation cells is approximated to be 500 mm.

(63) TABLE-US-00006 TABLE 6 Dimensions of a further embodiment of the flotation line 1 according to the current disclosure. Flotation Vol. , H, d, Drop, cell m.sup.3 mm mm mm 1 (20a) 380 8,610 8,000 — 1 (20b) 380 8,610 8,000 0 2 (21b) 340 7,810 8,000 800 2 (21b) 340 7,810 8,000 0 3 (22a) 300 7,010 8,000 800 3 (22b) 300 7,010 8,000 0 Sum 48,000 1,600

(64) In the embodiment presented in table 6, the length of the uniplanar flotation line is thus the sum of all flotation cell 20a, 20b, 21a, 21b, 22a, 22b diameters (48,000 mm) and the distances between the flotation cells (5×500 mm=2,500 mm), totaling 50,500 mm (50.5 m). As the decrease in the flotation unit launder lip height H (drop) is 1,600 mm (1.6 m), the angle β is 1.8°.

(65) If the flotation cells 20a, 20b, 21a, 21b, 22a, 22b are constructed such, that they are directly adjacent to each other, making distance D non-existent for practical purposes (approximated here by 20 mm), the angle β would increase to 2° (L=48,000 mm+5×20 mm=48,100 mm).

(66) It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above, instead they may vary within the scope of the claims.