Flotation plant and its uses, a method of changing a flotation tank in a tank module and a method of changing a module

Abstract

A flotation plant includes a tank module which includes a self-supporting framework having an inner space. The tank module includes at least one flotation tank. The flotation tank is disposed in the inner space of the self-supporting framework. The tank module is a self-supporting unit capable of being transferable and hoistable as an integral entity. The flotation plant includes at least two drive units for the rotation of drive shafts, each drive shaft being connected to a rotor for mixing and/or forming bubbles in the flotation tank. An overflow receptacle is disposed at the level of the upper part of the tank module for receiving an overflow from the flotation tanks. The flotation plant includes an overflow channel which is connected to the overflow receptacle for receiving and conducting the overflow from the overflow receptacle to a pumping means. The overflow channel is disposed outside the tank module.

Claims

1. A flotation plant, comprising: tank module including a self-supporting framework having an inner space, a framework bottom and framework sidewalls, the tank module including at least two flotation tanks, the at least two flotation tanks being disposed in the inner space of the self-supporting framework, the at least two flotation tanks being self-supporting structures capable of being transferred and hoisted as integral units, and the flotation tanks are placed inside the self-supporting framework without being attached to the framework bottom and the framework sidewalls, and the tank module being a self-supporting unit capable of being transferable and hoistable as an integral entity; at least two drive units for the rotation of drive shafts, each drive shaft being connected to a rotor for mixing and/or forming bubbles in the flotation tank; an overflow receptacle being disposed at the level of the upper part of the tank module for receiving an overflow from the flotation tanks; and an overflow channel connected to the overflow receptacle for receiving and conducting the overflow from the overflow receptacle to a pump, and the overflow channel is disposed outside the tank module.

2. The flotation plant according to claim 1, wherein the overflow channel is connected to the overflow receptacle by a releasable joint.

3. The flotation plant according to claim 1, wherein the overflow channel comprises sloping channel portions, the sloping channel portions extending in a lengthwise direction of the tank module, the sloping channel portions being inclined in relation to horizontal direction.

4. The flotation plant according to claim 1, wherein the overflow channel has a widthwise diameter of at least 250 mm.

5. The flotation plant according to claim 4, wherein the widthwise diameter of the overflow channel is 250 to 1200 mm, preferably 400 mm to 1000 mm.

6. The flotation plant according to claim 1, wherein the overflow channel is supported by brackets to the self-supporting framework of the tank module.

7. The flotation plant according to claim 1, wherein the flotation plant comprises an accessory module, the accessory module including a self-supporting framework having an inner space, the overflow channel being disposed in the inner space and supported by brackets to the self-supporting framework of the accessory module, the accessory module being a self-supporting unit capable of being transferable and hoistable as an integral entity, the accessory module being located on the side and next to the tank module.

8. The flotation plant according to claim 1, wherein the self-supporting framework of the tank module has a shape of a parallelepiped and comprises vertical side walls, and the overflow channel is connected to the overflow receptacle with a pipe, the pipe extending through the side wall.

9. The flotation plant according to claim 8, wherein the pipe is located at a height which is located within a range of 40% to 100% of the height of the tank module, wherein the total height of the tank module is 100%.

10. The flotation plant according to claim 1, wherein the overflow channel comprises a chute.

11. The flotation plant according to claim 1, wherein the overflow channel comprises a pipeline.

12. The flotation plant according to claim 1, wherein the flotation tank comprises plastic.

13. A method of operating the flotation plant, comprising: providing a flotation plant according to claim 1; and separating material by flotation based on differences of buoyancy properties of substances, or separating solid material by froth flotation based on differences of hydrophilic properties of substances, or concentrating ore by froth flotation, or flotation of substances containing abrasive material, or froth flotation of ore containing pyrite, silica, or chromite.

14. A method of changing the flotation tank in the tank module of the flotation plant according to claim 1, wherein the method comprises steps of: providing the flotation plant of claim 1, removing the flotation tank out from inside the framework, and installing another flotation tank into the framework.

15. A method of changing a tank module comprising providing a flotation plant according to claim 1, in which method the tank module subject of maintenance is replaced by another tank module and removing the tank module for maintenance and replacing the removed tank module with another tank module.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are included to provide a 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. In the drawings:

(2) FIG. 1 is a schematic side view of a first embodiment of the flotation plant according to the invention,

(3) FIG. 1a is a cross-section Ia-Ia from FIG. 1,

(4) FIG. 1b is an alternative cross-section to that shown in FIG. 1a,

(5) FIG. 2 is a schematic cross-section II-II from FIG. 1,

(6) FIG. 2a is a cross-section IIa-IIa from FIG. 2,

(7) FIG. 2b is an alternative cross-section to that shown in FIG. 2a.

(8) FIG. 3 is a schematic cross-section corresponding to FIG. 2 of a second embodiment of the flotation plant according to the invention,

(9) FIG. 3 is a schematic cross-section corresponding to FIG. 2 of a third embodiment of the flotation plant according to the invention,

(10) FIG. 4 is a schematic cross-section corresponding to FIG. 2 of a fourth embodiment of the flotation plant according to the invention

(11) FIG. 5 is a schematic cross-section corresponding to FIG. 2 of a fifth embodiment of the flotation plant according to the invention

DETAILED DESCRIPTION OF THE INVENTION

(12) 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.

(13) Referring to FIGS. 1-5, they show a froth flotation plant that is configured for implementing froth flotation. In this embodiment the froth flotation plant has been assembled from self-supporting modules that together form a modular froth flotation plant. The modules from which the froth flotation plant has been built are removably stacked on top of each other to form a three-storeyed structure having a first storey I at the bottom, a second storey II in the middle and a top storey III. A tank module 1 located in the second storey II.

(14) A tank module 1, which is located at the second storey II, includes a self-supporting framework 2 having an inner space 3. In the example shown in FIG. 1, the tank module 1 includes four froth flotation tanks 4 arranged in a row in the inner space 3 of the self-supporting framework 2 of the tank module 1. The flotation tanks 4 are arranged in a row and in fluid communication with each other so that an underflow can flow through the tanks. The number of the froth flotation tanks 4 within the tank module 1 is one to six, preferably one to four. The tank module 1 is a self-supporting unit capable of being transferable and hoistable as an integral entity.

(15) As shown in FIGS. 2, 2a and 2b, the self-supporting framework 2 comprises a framework bottom 18 and the framework sidewalls 16. The froth flotation tanks 4 are also self-supporting structures that can be transferred and hoisted as integral units. The froth flotation tanks 4 are placed inside the self-supporting framework 2 without being attached to the framework bottom 18 and the framework sidewalls 16.

(16) One drive unit 5 for each froth flotation tank 4 is disposed to rotate a drive shaft 6. The drive shaft 6 is connected to a rotor 7 for mixing and forming bubbles in the froth flotation tank 4. The drive shaft 6 is hollow so that gas can be fed through it to the rotor 7 which disperses it to the feedstock subject of flotation in the flotation tank. A stator 31 is disposed to surround the rotor 7. The stator 31 is connected to the framework 2 through the bottom 32.

(17) In the embodiments shown in FIGS. 1 to 5 the froth flotation plant includes a drive module 20 which is located at the third storey III so that the drive module 20 is removably stacked on top of the tank module 1. The drive module 20 includes four drive units 5 for the rotation of the drive shafts 6.

(18) In the examples shown in FIGS. 2 and 3, the stack formed of the tank module 1 and the drive module 20 is removably placed on top of a pump sump module 21 located at the first storey I of the froth flotation plant. Referring to FIG. 1, the pump sump module 21 includes a pumping means 10. The pumping means 10 may include a first pump 22 for pumping the overflow which comes via an overflow channel 9 to a first sump tank 23 wherefrom the settled overflow can be pumped away by the first pump 22 to further processing. As shown in FIG. 1, the pump sump module 21 may also include a second pump 24 for pumping the underflow which comes from the froth flotation tank 4 via a discharge box 25 to a second sump tank 26 wherefrom it can be pumped away by the second pump 24 to further processing.

(19) Referring again to FIGS. 1-5, the froth flotation plant comprises one overflow receptacle 8 for each one of the froth flotation tanks 4 for receiving an overflow overflowing from the flotation tank 4. The overflow receptacles 8 are disposed at the level of the upper part of the tank module 1.

(20) In the examples shown in FIGS. 2 and 4 the overflow receptacles 8 are inside the second self-supporting framework 2 of the tank module 1 and each overflow receptacle 8 is connected to the froth flotation tank 1 to be transferable and hoistable as an integral unit with the froth flotation tank. Preferably, the froth flotation tanks 1 are made of plastics, e.g. polypropylene or polyethylene. Preferably, the overflow receptacles 8 are made of the same material as the froth flotation tanks. The froth flotation tank 4 and the overflow flow receptacle 8 are connected to each other by welding.

(21) In the examples shown in FIGS. 3 and 5 the overflow receptacle 8 is disposed outside the tank module 1 on one side of the tank module. In these examples the froth flotation plant comprises an accessory module 12. The accessory module 12 is a self-supporting unit capable of being transferable and hoistable as an integral entity 1. The accessory module 12 is placed on on one side and next to the tank module 1 at the level of the second storey II. The accessory module 12 includes a self-supporting framework 13 having an inner space 14. The overflow receptacle 8 is arranged in an inner space 14 of the accessory module 12. The overflow receptacle 8 is supported by brackets to a self-supporting framework 13 of the accessory module 12.

(22) In the examples shown in FIGS. 3 and 5 the accessory module 12 is removably placed on top of the pump sump module 21. The tank module 1 and the drive module 20 are removably placed on top of a foundation module 27 located at the first storey I.

(23) With reference to FIGS. 1-5, an overflow channel 9 is connected in fluid communication with the overflow receptacles 8 for receiving and conducting the overflow from the overflow receptacle 8 to the pumping means 10. The overflow channel 9 is connected to the overflow receptacles 8 by releasable joints 28. The overflow channel 9 is disposed outside the tank module 1.

(24) In the examples shown in FIGS. 2 and 3 the overflow channel 9 is supported by brackets 11 to the self-supporting framework 2 of the tank module 1.

(25) In the examples shown in FIGS. 4 and 5 the overflow channel 9 is disposed in the inner space 14 of the self-supporting framework 13 of the accessory module 12. The overflow channel is supported by brackets 15 to the self-supporting framework 13 of the accessory module 12.

(26) The overflow channel 9 is connected to the overflow receptacle 8 with a pipe 17, the pipe extending through the side wall 16. The pipe 17 is located at a height which is located within a range of 40% to 100% of the height of the tank module 1, wherein the total height of the tank module is 100%.

(27) FIG. 1a shows that the overflow channel 9 may comprise a pipeline having a closed shape of cross-section. FIG. 1b illustrates an alternative wherein the overflow channel 9 may comprise a chute having an open shape of the cross-section. Preferably, in order to ensure continuous flowing of the overflow and to avoid clogging of the overflow channel 9 it has a widthwise diameter of at least 250 mm. More preferably the widthwise diameter of the overflow channel 9 is 250 to 1200 mm. Most preferably the widthwise diameter of the overflow channel 9 is 400 mm to 1000 mm.

(28) As mentioned, the froth flotation tanks 4 are self-supporting structures that can be transferred and hoisted as integral units. The froth flotation tank 5 is made of a thermoplastic polymer, e.g. polyethylene PE or polypropylene PP which is very resistant to abrasion. The wall thickness of the self-supporting tank 5 is 5-30 mm. The volume of the froth flotation tank 4 is 0.5-20 m.sup.3, more preferably 1-15 m.sup.3, most preferably 1-8 m.sup.3.

(29) As shown in FIG. 2b the self-supporting froth flotation tank 4 may be cylindrical whereby it has a circular cross-section. Preferably, the froth flotation tank 4 is cylindrical when the volume of the froth flotation tank is at most 8 m.sup.3.

(30) Preferably, the flotation tank 4 has a circular mouth 30. A circular mouth 30 gives stiffness for the whole structure of the flotation tank 4.

(31) FIG. 2a illustrates that the froth flotation tank 4 that has a volume greater than 8 m.sup.3 preferably has a rectangular or quadrangular cross-section. The froth flotation tank 4 having a rectangular or quadrangular cross-section comprises four tank sidewalls 19. At least two of the tank sidewalls 19 lean against the framework sidewalls 16 whereby the framework sidewalls 16 may support the tank sidewalls against the hydrostatic pressure. The tank sidewalls 19 comprise a planar wall part. The planar wall part has a width w which is at least 70% of the total width W of the tank sidewall. At least two of the planar parts of the tank sidewalls lean against the framework sidewalls 16.

(32) 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.