CA2462740A1 - Method for froth flotation - Google Patents
Method for froth flotation Download PDFInfo
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- CA2462740A1 CA2462740A1 CA002462740A CA2462740A CA2462740A1 CA 2462740 A1 CA2462740 A1 CA 2462740A1 CA 002462740 A CA002462740 A CA 002462740A CA 2462740 A CA2462740 A CA 2462740A CA 2462740 A1 CA2462740 A1 CA 2462740A1
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- slurry
- contactor vessel
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- air
- contactor
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000009291 froth flotation Methods 0.000 title claims abstract description 13
- 239000002002 slurry Substances 0.000 claims abstract description 72
- 230000002209 hydrophobic effect Effects 0.000 claims abstract description 34
- 239000000463 material Substances 0.000 claims abstract description 30
- 238000000926 separation method Methods 0.000 claims abstract description 25
- 239000002245 particle Substances 0.000 claims abstract description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000012141 concentrate Substances 0.000 claims abstract description 7
- 239000000203 mixture Substances 0.000 claims abstract description 6
- 238000005188 flotation Methods 0.000 claims description 25
- 238000007599 discharging Methods 0.000 claims description 5
- 230000014759 maintenance of location Effects 0.000 claims description 5
- 239000003153 chemical reaction reagent Substances 0.000 claims description 4
- 238000012544 monitoring process Methods 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 15
- 239000011707 mineral Substances 0.000 description 15
- 238000005191 phase separation Methods 0.000 description 4
- 238000011084 recovery Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000881 depressing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003623 enhancer Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/02—Froth-flotation processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/02—Separation of non-miscible liquids
- B01D17/0205—Separation of non-miscible liquids by gas bubbles or moving solids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/02—Separation of non-miscible liquids
- B01D17/0208—Separation of non-miscible liquids by sedimentation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/02—Separation of non-miscible liquids
- B01D17/04—Breaking emulsions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/02—Froth-flotation processes
- B03D1/028—Control and monitoring of flotation processes; computer models therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/1443—Feed or discharge mechanisms for flotation tanks
- B03D1/1456—Feed mechanisms for the slurry
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/24—Pneumatic
- B03D1/247—Mixing gas and slurry in a device separate from the flotation tank, i.e. reactor-separator type
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/02—Froth-flotation processes
- B03D1/025—Froth-flotation processes adapted for the flotation of fines
Landscapes
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biotechnology (AREA)
- General Engineering & Computer Science (AREA)
- Physical Water Treatments (AREA)
Abstract
A method of froth flotation where a pressurized stream of feed slurry and a pressurized stream of air are delivered to a contactor vessel. The feed slurry includes a mixture of particles of oil or hydrophobic materials and water. The feed slurry and the stream of pressurized air are maintained within certain flow and pressure parameters a nd allowed to intermix within the contactor vessel to permit the attachment of air bubbles to the particles of oil or hydrophobic materials thereby forming particle-bubble aggregates. The contents of the contactor vessel are discharged into a separation vessel where said particle-bubble aggregates form a froth for removal as a concentrate.</SDOAB >
Description
TITLE OF THE INVENTION
Method for Froth Flotation FIELD OF THE INVENTION
This invention relates to a method for the separation of particles of oil or hydrophobic minerals from a water or mineral pulp or slurry. In particular the invention relates to a new and useful method for froth flotation.
BACKGROUND OF THE INVENTION
In the mining and mineral processing industries froth flotation has long been used as a means to separate or concentrate valuable or desirable minerals from waste materials or gangue. In flotation, finely ground particles of an ore are typically added to water to produce a slurry that is then treated with a reagent to make the surface of one or more mineral components sufficiently hydrophobic such that the mineral surface will preferentially adhere to an air bubble rather than remain wetted. The remainder of the ore is preferably made or kept sufficiently hydrophilic to enable the hydrophobic and hydrophilic components to be separated from each other when placed in an aerated volume of water. That is, when immersed in water and subjected to an injected stream of air, small bubbles attach to the hydrophobic mineral components causing them to float to the surface where they can be collected and removed for further processing. The remaining hydrophilic components tend to settle at the bottom of the volume of water and can be extracted therefrom using a variety of mechanical methods. To aid in the separation of the mineral components a further chemical may be added to produce a controllable froth. Depending upon the nature of the minerals contained within an ore, the component sought to be concentrated rnay be the hydrophobic component that is separated with the froth or, in other cases, the desired component may be hydrophilic and may remain immersed in the water.
For separation to be achieved in a flotation system air bubbles must come into contact with hydrophobic particles within the flotation cell or the phase separation vessel. To achieve a desired throughput and to ensure that all of the hydrophobic component has the opportunity to be exposed to injected air, flotation cells have previously tended to be relatively large pieces of equipment that often contain an impeller to agitate the slurry and to disperse bubbles throughout the cell. While relatively effective, such equipment tends to be expensive to manufacture, difficult or essentially impossible to transport from site to site, and can consume relatively large amounts of energy through the use of electric motors needed to drive the impeller.
Method for Froth Flotation FIELD OF THE INVENTION
This invention relates to a method for the separation of particles of oil or hydrophobic minerals from a water or mineral pulp or slurry. In particular the invention relates to a new and useful method for froth flotation.
BACKGROUND OF THE INVENTION
In the mining and mineral processing industries froth flotation has long been used as a means to separate or concentrate valuable or desirable minerals from waste materials or gangue. In flotation, finely ground particles of an ore are typically added to water to produce a slurry that is then treated with a reagent to make the surface of one or more mineral components sufficiently hydrophobic such that the mineral surface will preferentially adhere to an air bubble rather than remain wetted. The remainder of the ore is preferably made or kept sufficiently hydrophilic to enable the hydrophobic and hydrophilic components to be separated from each other when placed in an aerated volume of water. That is, when immersed in water and subjected to an injected stream of air, small bubbles attach to the hydrophobic mineral components causing them to float to the surface where they can be collected and removed for further processing. The remaining hydrophilic components tend to settle at the bottom of the volume of water and can be extracted therefrom using a variety of mechanical methods. To aid in the separation of the mineral components a further chemical may be added to produce a controllable froth. Depending upon the nature of the minerals contained within an ore, the component sought to be concentrated rnay be the hydrophobic component that is separated with the froth or, in other cases, the desired component may be hydrophilic and may remain immersed in the water.
For separation to be achieved in a flotation system air bubbles must come into contact with hydrophobic particles within the flotation cell or the phase separation vessel. To achieve a desired throughput and to ensure that all of the hydrophobic component has the opportunity to be exposed to injected air, flotation cells have previously tended to be relatively large pieces of equipment that often contain an impeller to agitate the slurry and to disperse bubbles throughout the cell. While relatively effective, such equipment tends to be expensive to manufacture, difficult or essentially impossible to transport from site to site, and can consume relatively large amounts of energy through the use of electric motors needed to drive the impeller.
SUMMARY OF THE INVENTION
The present invention provides a method for froth flotation that permits the separation of fine particles of oil or hydrophobic minerals from an aqueous mineral pulp or slurry by creating an improved environment for the attachment of air bubbles onto hydrophobic particles to permit subsequent separation in a flotation cell or phase separation vessel. Utilization of the inventive method allows for th.e use of substantially smaller separation vessels than conventional flotation cells and systems while attaining generally the same or comparable levels of recovery. In particular, employment of the method described herein substantially reduces the volume of air that is required during the flotation process, thereby allowing for the use of smaller vessels which in turn can have a significant impact on the capital cost of equipment, the size of the processing plant necessary to house the equipment and the overall operating costs of the plant.
Accordingly, in one of its aspects the invention provides a method of froth flotation comprising the steps of delivering a pressurized stream of feed slurry and a pressurized stream of air to a contactor vessel, said feed slurry including a mixture of particles of oil or hydrophobic materials and water; through the use of a flow obstruction maintaining said contactor vessel at a pressure of from 18 to 25 pounds per square inch gauge and causing said feed slurry and said stream of pressurized air to intermix within said contactor vessel to create a mixture having a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5, said mixing of said feed slurry and said air within said pressurized contactor vessel allowing for the attachment of air bubbles to said particles of oil or hydrophobic materials forming particle-bubble aggregates;
maintaining the flow of said feed slurry and said pressurized air through said contactor vessel at a rate of from 1 to 3.5 meters per second, said contactor vessel constructed to permit a slurry retention time of from 1 to 2 seconds at a flow rate through said contactor vessel of from 1 to 3.5 meters per second; and, thereafter, discharging the contents of said contactor vessel through said flow obstruction into a separation vessel where said particle-bubble aggregates form a froth for removal as a concentrate.
In a further aspect the invention provides a method of froth flotation for the separation of a hydrophobic material from a hydrophilic material in an aqueous slurry containing particles of both hydrophobic and hydrophilic materials, the method comprising the steps of delivering a pressurized stream of said slurry to a contactor vessel;
injecting a stream ofpressurized air into said slurry within said contactor vessel, said air injected at a rate sufficient to establish a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5 within said contactor vessel; maintaining said contactor vessel at an internal pressure of from 18 to 25 pounds per square inch gauge such that said slurry and permitting said stream of pressurized air to intermix to aid in the attachment of air bubbles to at least a portion of said hydrophobic material in said slurry;
maintaining said slurry and said air within said contactor vessel for a retention time of from 1 to 2 seconds; and, thereafter discharging said slurry and said air from said contactor vessel into a separation vessel where said hydrophobic material with air bubbles attached thereto forms a froth for removal as a concentrate.
Further aspects and advantages of the invention will become apparent from the following description taken together with the accompanying drawings.
The present invention provides a method for froth flotation that permits the separation of fine particles of oil or hydrophobic minerals from an aqueous mineral pulp or slurry by creating an improved environment for the attachment of air bubbles onto hydrophobic particles to permit subsequent separation in a flotation cell or phase separation vessel. Utilization of the inventive method allows for th.e use of substantially smaller separation vessels than conventional flotation cells and systems while attaining generally the same or comparable levels of recovery. In particular, employment of the method described herein substantially reduces the volume of air that is required during the flotation process, thereby allowing for the use of smaller vessels which in turn can have a significant impact on the capital cost of equipment, the size of the processing plant necessary to house the equipment and the overall operating costs of the plant.
Accordingly, in one of its aspects the invention provides a method of froth flotation comprising the steps of delivering a pressurized stream of feed slurry and a pressurized stream of air to a contactor vessel, said feed slurry including a mixture of particles of oil or hydrophobic materials and water; through the use of a flow obstruction maintaining said contactor vessel at a pressure of from 18 to 25 pounds per square inch gauge and causing said feed slurry and said stream of pressurized air to intermix within said contactor vessel to create a mixture having a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5, said mixing of said feed slurry and said air within said pressurized contactor vessel allowing for the attachment of air bubbles to said particles of oil or hydrophobic materials forming particle-bubble aggregates;
maintaining the flow of said feed slurry and said pressurized air through said contactor vessel at a rate of from 1 to 3.5 meters per second, said contactor vessel constructed to permit a slurry retention time of from 1 to 2 seconds at a flow rate through said contactor vessel of from 1 to 3.5 meters per second; and, thereafter, discharging the contents of said contactor vessel through said flow obstruction into a separation vessel where said particle-bubble aggregates form a froth for removal as a concentrate.
In a further aspect the invention provides a method of froth flotation for the separation of a hydrophobic material from a hydrophilic material in an aqueous slurry containing particles of both hydrophobic and hydrophilic materials, the method comprising the steps of delivering a pressurized stream of said slurry to a contactor vessel;
injecting a stream ofpressurized air into said slurry within said contactor vessel, said air injected at a rate sufficient to establish a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5 within said contactor vessel; maintaining said contactor vessel at an internal pressure of from 18 to 25 pounds per square inch gauge such that said slurry and permitting said stream of pressurized air to intermix to aid in the attachment of air bubbles to at least a portion of said hydrophobic material in said slurry;
maintaining said slurry and said air within said contactor vessel for a retention time of from 1 to 2 seconds; and, thereafter discharging said slurry and said air from said contactor vessel into a separation vessel where said hydrophobic material with air bubbles attached thereto forms a froth for removal as a concentrate.
Further aspects and advantages of the invention will become apparent from the following description taken together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show the preferred embodiments of the present invention in which:
Figure 1 is a schematic side sectional view of an apparatus for froth flotation for use in accordance with a preferred embodiment of the method comprising the present invention.
For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show the preferred embodiments of the present invention in which:
Figure 1 is a schematic side sectional view of an apparatus for froth flotation for use in accordance with a preferred embodiment of the method comprising the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention may be embodied in a number of different forms. However, the specification and drawings that follow describe and disclose only some of the specific forms of the invention and are not intended to limit the scope of the invention as defined in the claims that follow herein.
An apparatus constructed for use when practicing a preferred embodiment of the method comprising the present invention is shown schematically in side sectional view in Figure 1. Figure 1 depicts a contactor vessel 1 that is connected to a flotation cell or phase separation vessel 2. Contactor vessel 1 includes a slurry input port 3, an air input port 4 and an output port 5, and has a generally hollow interior 6. While the contactor vessel shown in Figure 1 is a pipe chamber, it will be appreciated from a complete 1 S understanding of the invention that other physical forms of vessel 1 could also be employed while remaining within the broad scope of the invention.
When assembled for operation, the slurry input port 3 of contactor vessel 1 is operatively connected to a source of pressurized slurry. Typically, the slurry would be comprised of an aqueous mixture of finely ground minerals or other materials that have previously undergone any conditioning stages that may be necessary in order to obtain separation of various components my means of froth flotation. For example, depending upon the nature of the minerals or materials contained within the slurry, a variety of different commonly used flotation reagents may be added for purposes of making one of the components of the slurry hydrophobic and/or rendering other components hydrophilic (or otherwise depressing certain elements or components). In addition, in some instances it may also be desirable to add floculants, froth enhancers, stabilizers, or other chemicals or reactants that are commonly used in the flotation field.
Referring again to Figure l, when assembled in an operative state air input port 4 of contactor vessel 1 is connected to a source of pressurized air for injecting air into the generally hollow interior 6 of the contactor vessel. Tn this manner, pressurized slurry entering contactor vessel 1 through slurry input port 3 is intermixed with pressurized air injected through air input port 4 causing air bubbles to come into contact with hydrophobic materials within the slurry. This allows for the attachment of air bubbles 1 S to the hydrophobic particles forming particle-bubble aggregates. To help assist in the intermixing of the injected air with the stream of pressurized slurry, in one embodiment of the invention slurry input port 3 is arranged at an angle of approximately 45 degrees to the longitudinal axis of contactor vessel 1. In an alternate embodiment the relative positions of slurry input port 3 and air input port 4 may be reversed from that shown in Figure 1.
The present invention may be embodied in a number of different forms. However, the specification and drawings that follow describe and disclose only some of the specific forms of the invention and are not intended to limit the scope of the invention as defined in the claims that follow herein.
An apparatus constructed for use when practicing a preferred embodiment of the method comprising the present invention is shown schematically in side sectional view in Figure 1. Figure 1 depicts a contactor vessel 1 that is connected to a flotation cell or phase separation vessel 2. Contactor vessel 1 includes a slurry input port 3, an air input port 4 and an output port 5, and has a generally hollow interior 6. While the contactor vessel shown in Figure 1 is a pipe chamber, it will be appreciated from a complete 1 S understanding of the invention that other physical forms of vessel 1 could also be employed while remaining within the broad scope of the invention.
When assembled for operation, the slurry input port 3 of contactor vessel 1 is operatively connected to a source of pressurized slurry. Typically, the slurry would be comprised of an aqueous mixture of finely ground minerals or other materials that have previously undergone any conditioning stages that may be necessary in order to obtain separation of various components my means of froth flotation. For example, depending upon the nature of the minerals or materials contained within the slurry, a variety of different commonly used flotation reagents may be added for purposes of making one of the components of the slurry hydrophobic and/or rendering other components hydrophilic (or otherwise depressing certain elements or components). In addition, in some instances it may also be desirable to add floculants, froth enhancers, stabilizers, or other chemicals or reactants that are commonly used in the flotation field.
Referring again to Figure l, when assembled in an operative state air input port 4 of contactor vessel 1 is connected to a source of pressurized air for injecting air into the generally hollow interior 6 of the contactor vessel. Tn this manner, pressurized slurry entering contactor vessel 1 through slurry input port 3 is intermixed with pressurized air injected through air input port 4 causing air bubbles to come into contact with hydrophobic materials within the slurry. This allows for the attachment of air bubbles 1 S to the hydrophobic particles forming particle-bubble aggregates. To help assist in the intermixing of the injected air with the stream of pressurized slurry, in one embodiment of the invention slurry input port 3 is arranged at an angle of approximately 45 degrees to the longitudinal axis of contactor vessel 1. In an alternate embodiment the relative positions of slurry input port 3 and air input port 4 may be reversed from that shown in Figure 1.
Output port 5 of contactor vessel 1 is connected to flotation cell 2 by means of piping 7 such that the contents of the contactor vessel (including the pressurized slurry and injected air) may be delivered to flotation cell 2 as they exit the contactor vessel. In a preferred embodiment of the invention the contents of the contactor vessel are pumped through output port 5, into piping 7 and eventually through a generally cylindrical vertically oriented distributor 8 that is situated preferably at or near the center of flotation cell 2. In the embodiment shown in Figure l, distributor 8 has an enclosed upper end and a series of rectangular shaped slots 9 positioned about its vertical axis and through which the aerated slurry passes. Once released into the flotation cell, the particle-bubble aggregates within the slurry will separate from the hydrophilic component of the slurry by means of traditional froth flotation. That is, the particle-bubble aggregates will tend to float upwardly through the separation vessel and accumulate at or near the top of the vessel where they can be collected and removed as a concentrate. A froth la~ulder 10 may be used to help collect the froth and direct it out 1 S of flotation cell 2 for further processing. The hydrophilic materials within the slurry settle at the bottom of the flotation cell and may be removed by any one of a vaxiety of commonly used methods. In these regards, the embodiment shown in Figure 1 indicates the use of a hopper 11 situated on the bottom of flotation cell 2 which tends to collect and direct settled hydrophilic materials to an outlet port 12.
In accordance with one aspect of the present invention, dining its operation contactor vessel 1 is maintained in a pressurized state in order to help assist in the attachment of air bubbles to particles of hydrophobic materials prior to the discharge of the slurry and air from the contactor vessel into flotation cell 2. It has been found that maintaining the contents of contactor vessel 1 in a pressurized environment helps to assist in the intermixing of air that is injected into the slurry and encourages a more consistent and effective attachment of air bubbles to hydrophobic particles. It will be appreciated that depending upon the nature of the materials undergoing separation and the volume and throughput of the equipment in question, the optimum pressure under which contactor vessel 1 should be maintained may vary. However, a pressure of from about 18 to about 25 pounds per square inch gauge has been found to be most effective. It has also been determined that where contactor vessel 1 is a pipe chamber, sizing the chamber in a manner such that the velocity of slurry travelling therethough is from about 1 to about 3.5 meters per second such that a retention time of from approximately 1 to 2 seconds is established permits effective particle-bubble attachment at an enhanced throughput.
In order to maintain the interior of contactor vessel 1 in a pressurized state during its use the invention contemplates the employment of a flow obstruction 13 that effectively hinders the flow of material through the contactor vessel, thereby creating back pressure which tends to establish and maintain a pressurized state within hollow interior 6 of contactor vessel 1. It will be appreciated that the use of a flow obstructions will also have the result of increasing the velocity of material exiting the contactor vessel through the orifice or opening in the flow obstruction. It is expected that under most conditions the velocity of materials flowing through flow obstructions 13 will be from about 10 to about 20 meters per second.
Flow obstruction 13 may take any one of a wide variety of different mechanical structures that range from a simple reduction in the cross sectional area of the interior of the contactor vessel or the piping that connects contactor vessel 1 to flotation cell 2, to more complex fixed or adjustable orifice plates, rrmscle valves or pinch valves. The particular structure of flow obstruction 13 will to a large part be dependent upon the end use of contactor vessel 1 and the amount of flexibility and control over the operation of the vessel that is desired.
In cases where it is desirable to be able to adjust or modify the operation of contactor vessel l, there may be included a pressure sensor 17 in communication with hollow interior 6 of the contactor vessel to allow fox the monitoring of its internal working pressure. As pressure sensor 17 senses fluctuations in the pressure within contactor vessel l, signals may be generated to alert an operator so that adjustments can be made to either the rate of delivery of pressurized slurry to tlxe contactor vessel and/or the rate of delivery of pressurized air and/or the operation of flow obstruction 13 (where the mechanism comprising the flow obstruction allows for the adjustment of the orifice or flow passageway therethrough). Through altering the amount of slurry and/or air delivered to the contactor vessel and/or the functioning of the flow obstruction, an operator will be able to effectively adjust and maintain the internal pressure of contactor vessel 1 within a pre-determined range.
Complete automation of the process may be achieved through the utilization of a microprocessor control 18 and an actuator connected to flow obstruction 13 to adjust the size of the opening therethrough. Typically such an actuator would be an electric, hydraulic or pneumatic solenoid. Signals generated by pressure sensor 17 may be directed to microprocessor control 18 which in tww is connected to the actuator to permit automated adjustment of flow obstruction 13. If desired, microprocessor control 18 may also be connected to a throttle valve (not shown) or other structure (for example, the slurry pump) so that the microprocessor is able to adjust the flow of pressurized slurry into contactor vessel 1. In this manner, microprocessor control 18 is 1 S able to automatically compensate for varying operational conditions that may result in a fluctuation of pressure within the contactor vessel l, thereby maintaining a desired pressure therein. Microprocessor control 18 may also be connected to valves, compressors or other devices used to generate the stream of pressurized gas injected into the slurry as a further means to control the overall process parameters. It will further be appreciated that where flow obstruction 13 is a fixed orifice, control of internal pressures with the contactor may be achieved through using the microprocessor to control the rate of delivery of the feed slurry and/or the injected air.
It will therefore be appreciated by those skilled in the art from a complete understanding of the above invention that the described apparatus and method provides a mechanism for separating particles of oil or hydrophobic minerals or other materials from a water or mineral pulp or slurry by creating an improved environment for the attachment of air bubbles to hydrophobic particles, thereby allowing far the subsequent separation of the hydrophobic and hydrophilic materials in a flotation cell or phase separation vessel. The air/hydrophobic particle contact is created under pressure inside a contact chamber and outside of the separation vessel. In this manner the described method and apparatus provides for an efficient environment fox attaching air bubbles to the hydrophobic material before the slurry is released into the separation vessel.
It has been found that through the use of contactor vessel l, and with the establishment of a pressurized environment within which the slurry and air stream are intermixed, a maximum slurry/gas volume flow ratio of from approximately 1:1 to approximately 1:5 ,measured after the flow obstruction, can be established while transporting material through the contactor vessel. Such slurry-to-air ratios are considerably less that those commonly used in the art. When the contents of contactor vessel 1 are delivered to the flotation cell the expansion of the gas on discharge will provide a gasalurry volume ratio in the flotation cell as high as approximately 2.5:1 and a gas velocity in the separation vessel as high as 4 centimeters per second. Accordingly, not only does the pressurized state of contactor vessel 1 enhance the bubble-hydrophobic particle attachment, but it also forces the attachment of pressurized bubbles of air to the hydrophobic particles. Upon release into the flotation cell the pressurized bubbles expand to provide an enhanced gas lift during the separation process. This structure has proven to permit the use of separation tank volumes that can be in the range of 2 to 3 times smaller than that required by conventional mechanical cells, while attaining the same or similar rates of recovery. In addition, the described method generally permits the use of separation vessels that do not require internal agitators or impellers.
It is to be understood that what has been described are the preferred embodiments of the invention and that it may be possible to make variations to these embodiments while staying within the broad scope of the invention. Some of these variations have been discussed while others will be readily apparent to those skilled in the art.
In order to maintain the interior of contactor vessel 1 in a pressurized state during its use the invention contemplates the employment of a flow obstruction 13 that effectively hinders the flow of material through the contactor vessel, thereby creating back pressure which tends to establish and maintain a pressurized state within hollow interior 6 of contactor vessel 1. It will be appreciated that the use of a flow obstructions will also have the result of increasing the velocity of material exiting the contactor vessel through the orifice or opening in the flow obstruction. It is expected that under most conditions the velocity of materials flowing through flow obstructions 13 will be from about 10 to about 20 meters per second.
Flow obstruction 13 may take any one of a wide variety of different mechanical structures that range from a simple reduction in the cross sectional area of the interior of the contactor vessel or the piping that connects contactor vessel 1 to flotation cell 2, to more complex fixed or adjustable orifice plates, rrmscle valves or pinch valves. The particular structure of flow obstruction 13 will to a large part be dependent upon the end use of contactor vessel 1 and the amount of flexibility and control over the operation of the vessel that is desired.
In cases where it is desirable to be able to adjust or modify the operation of contactor vessel l, there may be included a pressure sensor 17 in communication with hollow interior 6 of the contactor vessel to allow fox the monitoring of its internal working pressure. As pressure sensor 17 senses fluctuations in the pressure within contactor vessel l, signals may be generated to alert an operator so that adjustments can be made to either the rate of delivery of pressurized slurry to tlxe contactor vessel and/or the rate of delivery of pressurized air and/or the operation of flow obstruction 13 (where the mechanism comprising the flow obstruction allows for the adjustment of the orifice or flow passageway therethrough). Through altering the amount of slurry and/or air delivered to the contactor vessel and/or the functioning of the flow obstruction, an operator will be able to effectively adjust and maintain the internal pressure of contactor vessel 1 within a pre-determined range.
Complete automation of the process may be achieved through the utilization of a microprocessor control 18 and an actuator connected to flow obstruction 13 to adjust the size of the opening therethrough. Typically such an actuator would be an electric, hydraulic or pneumatic solenoid. Signals generated by pressure sensor 17 may be directed to microprocessor control 18 which in tww is connected to the actuator to permit automated adjustment of flow obstruction 13. If desired, microprocessor control 18 may also be connected to a throttle valve (not shown) or other structure (for example, the slurry pump) so that the microprocessor is able to adjust the flow of pressurized slurry into contactor vessel 1. In this manner, microprocessor control 18 is 1 S able to automatically compensate for varying operational conditions that may result in a fluctuation of pressure within the contactor vessel l, thereby maintaining a desired pressure therein. Microprocessor control 18 may also be connected to valves, compressors or other devices used to generate the stream of pressurized gas injected into the slurry as a further means to control the overall process parameters. It will further be appreciated that where flow obstruction 13 is a fixed orifice, control of internal pressures with the contactor may be achieved through using the microprocessor to control the rate of delivery of the feed slurry and/or the injected air.
It will therefore be appreciated by those skilled in the art from a complete understanding of the above invention that the described apparatus and method provides a mechanism for separating particles of oil or hydrophobic minerals or other materials from a water or mineral pulp or slurry by creating an improved environment for the attachment of air bubbles to hydrophobic particles, thereby allowing far the subsequent separation of the hydrophobic and hydrophilic materials in a flotation cell or phase separation vessel. The air/hydrophobic particle contact is created under pressure inside a contact chamber and outside of the separation vessel. In this manner the described method and apparatus provides for an efficient environment fox attaching air bubbles to the hydrophobic material before the slurry is released into the separation vessel.
It has been found that through the use of contactor vessel l, and with the establishment of a pressurized environment within which the slurry and air stream are intermixed, a maximum slurry/gas volume flow ratio of from approximately 1:1 to approximately 1:5 ,measured after the flow obstruction, can be established while transporting material through the contactor vessel. Such slurry-to-air ratios are considerably less that those commonly used in the art. When the contents of contactor vessel 1 are delivered to the flotation cell the expansion of the gas on discharge will provide a gasalurry volume ratio in the flotation cell as high as approximately 2.5:1 and a gas velocity in the separation vessel as high as 4 centimeters per second. Accordingly, not only does the pressurized state of contactor vessel 1 enhance the bubble-hydrophobic particle attachment, but it also forces the attachment of pressurized bubbles of air to the hydrophobic particles. Upon release into the flotation cell the pressurized bubbles expand to provide an enhanced gas lift during the separation process. This structure has proven to permit the use of separation tank volumes that can be in the range of 2 to 3 times smaller than that required by conventional mechanical cells, while attaining the same or similar rates of recovery. In addition, the described method generally permits the use of separation vessels that do not require internal agitators or impellers.
It is to be understood that what has been described are the preferred embodiments of the invention and that it may be possible to make variations to these embodiments while staying within the broad scope of the invention. Some of these variations have been discussed while others will be readily apparent to those skilled in the art.
Claims (13)
1. A method of froth flotation comprising the steps of:
(i) delivering a pressurized stream of feed slurry and a pressurized stream of air to a contactor vessel, said feed slurry including a mixture of particles of oil or hydrophobic materials and water;
(ii) through the use of a flow obstruction maintaining said contactor vessel at a pressure of from 18 to 25 pounds per square inch gauge and causing said feed slurry and said stream of pressurized air to intermix within said contactor vessel to create a mixture having a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5, said mixing of said feed slurry and said air within said pressurized contactor vessel allowing for the attachment of air bubbles to said particles of oil or hydrophobic materials forming particle-bubble aggregates;
(iii) maintaining the flow of said feed slurry and said pressurized air through said contactor vessel at a rate of from 1 to 3.5 meters per second, said contactor vessel constructed to permit a slurry retention time of from 1 to 2 seconds at a flow rate through said contactor vessel of from 1 to 3.5 meters per second; and, (iv) thereafter, discharging the contents of said contactor vessel through said flow obstruction into a separation vessel where said particle-bubble aggregates form a froth for removal as a concentrate.
(i) delivering a pressurized stream of feed slurry and a pressurized stream of air to a contactor vessel, said feed slurry including a mixture of particles of oil or hydrophobic materials and water;
(ii) through the use of a flow obstruction maintaining said contactor vessel at a pressure of from 18 to 25 pounds per square inch gauge and causing said feed slurry and said stream of pressurized air to intermix within said contactor vessel to create a mixture having a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5, said mixing of said feed slurry and said air within said pressurized contactor vessel allowing for the attachment of air bubbles to said particles of oil or hydrophobic materials forming particle-bubble aggregates;
(iii) maintaining the flow of said feed slurry and said pressurized air through said contactor vessel at a rate of from 1 to 3.5 meters per second, said contactor vessel constructed to permit a slurry retention time of from 1 to 2 seconds at a flow rate through said contactor vessel of from 1 to 3.5 meters per second; and, (iv) thereafter, discharging the contents of said contactor vessel through said flow obstruction into a separation vessel where said particle-bubble aggregates form a froth for removal as a concentrate.
2. The method as claimed in claim 1 wherein the velocity of said slurry and said air passing through said flow obstruction is from 10 to 20 meters per second
3. The method as claimed in claim 1 including the step of adding one or more flotation reagents to said feed slurry prior to the delivery of said slurry to said contactor vessel.
4. The method as claimed in claim 1 wherein said flow obstruction comprises an orifice plate or valve which maintains pressure within said contactor vessel.
5. The method as claimed in claim 1 including the further step of monitoring the pressure within said contactor vessel and adjusting at least one of the rate of delivery of said pressurized stream of feed slurry to said contactor vessel, the rate of delivery of said pressurized air to said contactor vessel, and the operation of said flow obstruction, to maintain said pressure within said contactor vessel between 18 and 25 pounds per square inch gauge.
6. The method as claimed in claim 1 wherein said contactor vessel is a pipe chamber.
7. The method as claimed in claim 1 wherein said step of discharging said contents of said contactor vessel into said separation vessel is accomplished through pumping said slurry and said air through said contactor vessel and into said separation vessel through a generally cylindrical vertically oriented distributor having rectangular slots positioned about its vertical axis.
8. A method of froth flotation for the separation of a hydrophobic material from a hydrophilic material in an aqueous slurry containing particles of both hydrophobic and hydrophilic materials, the method comprising the steps of:
(i) delivering a pressurized stream of said slurry to a contactor vessel;
(ii) injecting a stream of pressurized air into said slurry within said contactor vessel, said air injected at a rate sufficient to establish a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5 within said contactor vessel, (iii) maintaining said contactor vessel at an internal pressure of from 18 to pounds per square inch gauge such that said slurry and permitting said stream of pressurized air to intermix to aid in the attachment of air bubbles to at least a portion of said hydrophobic material in said slurry;
(iv) maintaining said slurry and said air within said contactor vessel for a retention time of from 1 to 2 seconds; and, (v) thereafter discharging said slurry and said air from said contactor vessel into a separation vessel where said hydrophobic material with air bubbles attached thereto forms a froth for removal as a concentrate.
(i) delivering a pressurized stream of said slurry to a contactor vessel;
(ii) injecting a stream of pressurized air into said slurry within said contactor vessel, said air injected at a rate sufficient to establish a slurry-to-air ratio, measured after said flow obstruction, of from 1 to 5 within said contactor vessel, (iii) maintaining said contactor vessel at an internal pressure of from 18 to pounds per square inch gauge such that said slurry and permitting said stream of pressurized air to intermix to aid in the attachment of air bubbles to at least a portion of said hydrophobic material in said slurry;
(iv) maintaining said slurry and said air within said contactor vessel for a retention time of from 1 to 2 seconds; and, (v) thereafter discharging said slurry and said air from said contactor vessel into a separation vessel where said hydrophobic material with air bubbles attached thereto forms a froth for removal as a concentrate.
9. The method as claimed in claim 8 wherein said contactor vessel is maintained in a pressurized state through the use of a flow obstruction.
10. The method as claimed in claim 9 including the further step of monitoring the pressure within said contactor vessel and adjusting at least one of the rate of delivery of said pressurized stream of slurry to said contactor vessel, the rate of delivery of said stream of pressurized air to said contactor vessel, and the operation of said flow obstruction, to maintain said pressure within said contactor vessel from 18 to 25 pounds per square inch gauge.
11. The method as claimed in claim 10 wherein said flow obstruction is an orifice plate or a valve.
12. The method as claimed in claim 8 wherein said contactor vessel is a pipe chamber and is of a size such that the velocity of said slurry through said contactor vessel is from 1 to 3.5 meters per second.
13. The method as claimed in claim 8 including the step of adding one or more flotation reagents to said aqueous slurry prior to the delivery of said slurry to said contactor vessel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2462740A CA2462740C (en) | 2004-03-31 | 2004-03-31 | Method for froth flotation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2462740A CA2462740C (en) | 2004-03-31 | 2004-03-31 | Method for froth flotation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2462740A1 true CA2462740A1 (en) | 2005-09-30 |
| CA2462740C CA2462740C (en) | 2015-03-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2462740A Expired - Lifetime CA2462740C (en) | 2004-03-31 | 2004-03-31 | Method for froth flotation |
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| Country | Link |
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| CA (1) | CA2462740C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2572778A1 (en) | 2011-09-23 | 2013-03-27 | Siemens Aktiengesellschaft | Dispenser nozzle, flotation machine with dispenser nozzle and method for its operation |
| US20140224745A1 (en) * | 2011-09-03 | 2014-08-14 | Enhydra Ltd | Flotation apparatus |
| CN108246485A (en) * | 2018-03-28 | 2018-07-06 | 张红如 | A kind of adaptive impurity removing equipment of current stabilization and impurity-removing method |
-
2004
- 2004-03-31 CA CA2462740A patent/CA2462740C/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140224745A1 (en) * | 2011-09-03 | 2014-08-14 | Enhydra Ltd | Flotation apparatus |
| EP2572778A1 (en) | 2011-09-23 | 2013-03-27 | Siemens Aktiengesellschaft | Dispenser nozzle, flotation machine with dispenser nozzle and method for its operation |
| WO2013041343A1 (en) | 2011-09-23 | 2013-03-28 | Siemens Aktiengesellschaft | Dispersion nozzle, flotation machine equipped therewith, and method for operating same |
| CN108246485A (en) * | 2018-03-28 | 2018-07-06 | 张红如 | A kind of adaptive impurity removing equipment of current stabilization and impurity-removing method |
| CN108246485B (en) * | 2018-03-28 | 2023-06-09 | 张红如 | Steady-flow self-adaptive impurity removal equipment and impurity removal method |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2462740C (en) | 2015-03-24 |
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