Patent Application
20210379603
This invention relates generally to techniques for separating valuable material from unwanted material in a mixture, such as a pulp slurry; and more particularly, relates to a method and apparatus for separating valuable material from unwanted material in a mixture, such as a pulp slurry, e.g., using an engineered collection media.
In many industrial processes, flotation is used to separate valuable or desired material from unwanted material. By way of example, in this process a mixture of water, valuable material, unwanted material, chemicals and air is placed into a flotation cell. The chemicals are used to make the desired material hydrophobic and the air is used to carry the material to the surface of the flotation cell. When the hydrophobic material and the air bubbles collide they become attached to each other. The bubble rises to the surface carrying the desired material with it.
The performance of the flotation cell is dependent on the air bubble surface area flux and air bubble size distribution in the collection zone of the cell. The air bubble surface area flux is dependent on the size of the bubbles and the air injection rate. Controlling the air bubble surface area flux has traditionally been very difficult. This is a multivariable control problem and there are no dependable real time feedback mechanisms to use for control.
There is a need in the industry to provide a better way to separate valuable material from unwanted material, e.g., including in such a flotation cell, so as to eliminate problems associated with using air bubbles in such a separation process.
In the past, particles or substrates with a hydrophobic coating have been used to attract mineral particles. However, the durability of the coatings is limited due to adhesive or cohesive failure of the coating on the substrate.
The present invention provides a collection medium that is effective in selectively collecting mineral particles from an aqueous slurry without a surface coating. The collection medium has a compliant, tacky surface of low energy. The collection medium is synthesized as a reaction product of an isocyanate and polyol. To be more effective in collecting mineral particles, the collection medium is configured as a solid-phase body having a three-dimensional open-cell structure, open-network structure or a reticulated foam to provide a plurality of collection surfaces.
Careful selection of the isocyanate, polyol and surfactant used in controlling foam cell size provides a polyurethane foam suitable for selective mineral collection. For example, use of a hydrophobic polyol reacted with isocyanates such as 1,6-hexamethylene diisocyanate (HDI), 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane (IPDI), or 4,4′-diisocyanato dicyclohexylmethane, (H12MDI), methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI) will provide improved hydrophobicity. In general, polyols, including polyester polyols, polyether polyols, polycarbonate polyols, polycaprolactone polyols, polybutadiene polyols, polysulfide polyols or fluorinated polyols selected for high hydrophobicity may be utilized. Hydrophobicity may be further increased through use of a hydrophobic surfactant in the foam-making process. For example, alkyl or aryl EO-PO, polydimethylsiloxane-polyoxyalkylene block copolymers or fluorinated surfactants may be useful. Tackifiers are helpful in providing the necessary tack. For this, hydrogenated rosin resins, rosin esters, styrenated terpenes, polyterpenes, terpene phenolics, phenolic resins, and the like may be used. Various catalysts and blowing agents may be used to initiate the polymerization and foaming process. The final product is compliant, tough, hydrophobic, and tacky throughout its composition. It has improved durability due to the lack of sensitive coating.
The structure may be in the form of sheets, cubes, spheres, or other shapes as well as densities (described by pores per inch and pore size distribution), and levels of tortuosity that optimize surface access, surface area, mineral attachment/detachment kinetics, and durability. These structures may be additionally optimized to target certain mineral particle size ranges, with denser structures acquiring smaller particle sizes. In general, cellular densities may range from 10-200 pores per inch, more preferably 10-90 pores per inch, and most preferably 20-60 pores per inch.
The open-network structure or reticulated foam made from the reaction product of an isocyanate and polyol is herein referred to as a hydrophobic foam. It can be generally used as an engineered collection medium for mineral separation. The collection medium can take the form of synthetic beads, in a cube form or a sphere form. Each of the synthetic beads can be entirely made of the hydrophobic foam, or has a core with a surface layer, while the core can be made of various polymers, glass, ceramic, metal or magnetic material, the surface layer is made of the hydrophobic foam. The collection medium can take the form of a sheet to be used as a filter, a conveyor belt or any mineral collection substrate.
Thus, it is a first aspect of the present invention to provide an engineered collection medium, comprising
a solid-phase body configured with a three-dimensional open-cell structure to provide a plurality of collection surfaces, the three-dimensional open-cell structure made of a hydrophobic material for attracting one or more mineral particles to the collection surfaces, wherein the hydrophobic material is made of a reaction product of an isocyanate and a polyol.
According to the present invention, the isocyanate is selected from the group consisting of 1,6-hexamethylene diisocyanate, 1-isocyantato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane (IPDI), 4,4′-diisocyanato dicyclohexylmethane (H12MDI), methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI).
According to the present invention, the polyol is selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyol, polycaprolactone polyol, polybutadiene polyol, polysulfide polyol and fluorinated polyol.
According to the present invention, the hydrophobic material is made of the reaction product of the isocyanate and the polyol in the presence of a surfactant, catalyst and/or blowing agent.
According to the present invention, the surfactant is alkyl or aryl EO-PO, polydimethylsiloxane-polyoxyalkylene block copolymers or fluorinated surfactant.
According to the present invention, the hydrophobic material further comprises hydrogenated rosin resins, rosin esters, styrenated terpenes, polyterpenes, terpene phenolics, or phenolic resins.
According to the present invention, the solid-phase body comprises a body form of a sheet, cube, sphere.
According to the present invention, the three-dimensional open-cell structure comprises a cellular density in the range of 10 to 200 pores per inch.
According to the present invention, the three-dimensional open-cell structure comprises a cellular density in the range of 10 to 90 pores per inch, and preferably 20-60 pores per inch.
According to the present invention, the solid-phase body comprises a reticulated foam block providing the three-dimensional open-cell structure.
According to the present invention, the solid-phase body comprises a filter providing the three-dimensional open-cell structure, the structure having open cells to allow fluid in the aqueous mixture to flow through the filter.
According to the present invention, the solid-phase body comprises a conveyor belt having a surface configured with the three-dimensional open-cell structure.
According to the present invention, the three-dimensional open-cell structure comprises an open cell foam.
The second aspect of the present invention is an apparatus, which comprises:
a processor configured to receive one or more engineered collection media carrying mineral particles, each of said one or more engineered collection media comprises a solid phase body configured with a three-dimensional open-cell structure to provide a plurality of collection surfaces; and
releasing apparatus configured to remove the mineral particles from the collection surfaces, wherein the three-dimensional open-cell structure is made of a hydrophobic material for attracting one or more mineral particles to the collection surfaces, and the hydrophobic material is made of a reaction product of an isocyanate and a polyol.
According to the present invention, the isocyanate is selected from the group consisting of 1,6-hexamethylene diisocyanate, 1-isocyantato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane (IPDI), 4,4′-diisocyanato dicyclohexylmethane (H12MDI), methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI); the polyol is selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyol, polycaprolactone polyol, polybutadiene polyol, polysulfide polyol and fluorinated polyol.
According to the present invention, the hydrophobic material is made of the reaction product of the isocyanate and the polyol in the presence of surfactant, wherein the surfactant is alkyl or aryl EO-PO, polydimethylsiloxane-polyoxyalkylene block copolymers or fluorinated surfactant, and the hydrophobic material further comprises hydrogenated rosin resins, rosin esters, styrenated terpenes, polyterpenes, terpene phenolics, or phenolic resins.
According to the present invention, the releasing apparatus comprises a stirrer configured to provide mechanical agitation so as to remove the mineral particles from the collection surfaces.
According to the present invention, the solid phase body comprises a conveyor belt carrying the mineral particles, the releasing apparatus comprising a brushing device configured to rub against the conveyor belt so as to remove the mineral particles from the collection surfaces.
The third aspect of the present invention is a method for mineral recovery, comprising
providing a processor configured to receive one or more engineered collection media carrying mineral particles, each of said one or more engineered collection media comprises a solid phase body configured with a three-dimensional open-cell structure to provide a plurality of collection surfaces; and
applying interruption forces to the engineered collection medium carrying mineral particles so as to remove the mineral particles from the collection surfaces.
According to the present invention, the isocyanate is selected from the group consisting of 1,6-hexamethylene diisocyanate, 1-isocyantato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane (IPDI), 4,4′-diisocyanato dicyclohexylmethane (H12NDI), methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI), and the polyol is selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyol, polycaprolactone polyol, polybutadiene polyol, polysulfide polyol and fluorinated polyol.
According to the present invention, the hydrophobic material is made of the reaction product of the isocyanate and the polyol in the presence of surfactant, and the surfactant is alkyl or aryl EO-PO, polydimethylsiloxane-polyoxyalkylene block copolymers or fluorinated surfactant.
According to the present invention, the hydrophobic material further comprises hydrogenated rosin resins, rosin esters, styrenated terpenes, polyterpenes, terpene phenolics, or phenolic resins.
According to the present invention, the method further comprises:
providing a stirrer configured to provide mechanical agitation in a surfactant solution so as to remove the mineral particles from the collection surfaces.
According to the present invention, the solid phase body comprises a conveyor belt carrying the mineral particles, and the method further comprises causing a brushing device to rub against the conveyor belt for removing the mineral particles from the collection surfaces.
According to the present invention, the method further comprises:
providing a sonic source configured to provide ultrasonic waves in a liquid medium for remove the mineral particles from the collection surfaces.
According to some embodiments, the present invention may include, or take the form of, an engineered collection medium featuring a solid-phase body configured with a three-dimensional open-cell structure to provide a plurality of collection surfaces, causing the mineral particles to attach to the collection surfaces. The three-dimensional open cellular structure can be optimized to provide a compliant, tacky surface of low energy enhances collection of hydrophobic or hydrophobized mineral particles ranging widely in particle size. The collection medium, according to an embodiment of the present invention, is not coated. For example, polyurethane foam is itself the collection medium such that the polyurethane is synthesized to have the necessary properties for efficient and selective collection of hydrophobic particles.
The solid-phase body may include, or take the form of, a reticulated foam block providing the three-dimensional open-cell structure.
The solid-phase body may include a filter providing the three-dimensional open-cell structure, the structure having open cells to allow fluid in the aqueous mixture to flow through the filter.
The solid-phase body may include a conveyor belt having a surface configured with the three-dimensional open-cell structure.
The engineered collection media may include different open cell foams having different specific surface areas that are blended to recover a specific size distribution of mineral particles in the slurry.
According to some embodiments, the present invention may take the form of a method featuring steps for providing a processor configured to receive one or more engineered collection media carrying mineral particles, each of said one or more engineered collection media comprises a solid phase body configured with a three-dimensional open-cell structure to provide a plurality of collection surfaces, the three-dimensional open-cell structure is made of a hydrophobic material for causing the mineral particles to attach to collection surfaces. The hydrophobic material is a reaction product of an isocyanate and polyol. The method further comprises applying an interrupting force so as to remove the mineral particles from the collection surfaces.
The method may also include a step for providing a stirrer configured to provide mechanical agitation so as facilitate said interrupting, and wherein said interrupting is carried out in a surfactant.
The solid phase body may include a conveyor belt carrying the mineral particles, including where the method further includes a step for causing a brushing device to rub against the conveyor belt for removing the mineral particles from the collection surfaces.
The method may also include a step for providing a sonic source configured to provide ultrasonic waves in a liquid medium for removing the mineral particles from the collection surfaces. For example, ultrasound signals in the range of 20 KHz to 300 HKz for the sonic agitation. The synthetic beads carrying the mineral particles may be received along with a mixture having a first pH value, and the step for interrupting may include causing the synthetic beads carrying the mineral particles to contact with a medium having a second pH value lower than the first pH value, including where the second pH value ranges from 0 to 7.
The step of interrupting may include mechanically causing the synthetic beads to move against each other, including arranging a rotational means or device to stir the synthetic beads.
Part of the synthetic beads carrying the mineral particles may have a core made of a magnetic material, and the step of interrupting may include arranging a magnetic stirrer to stir the synthetic beads.
The synthetic beads carrying the mineral particles may be received along with a mixture, wherein said interrupting comprises selecting two or more of the following interrupting techniques: 1) lowering pH value of the mixture, 2) applying an ultrasound to the mixture; 3) increasing temperature of the mixture and 4) mechanically stirring the mixture. The selected interrupting techniques may be used on the mixture concurrently or sequentially.
In all these embodiments, the synthetic beads may be made of the hydrophobic foam or have a body made of polymer, glass or ceramic having a surface layer made of the hydrophobic foam, according to the present invention. As described above, the hydrophobic foam is an open-network or a three-dimensional open-cell structure made from a reaction product of an isocyanate and a polyol.
By way of further example, according to some embodiments, the present invention may take the form of an apparatus featuring a processor configured to receive a plurality of engineered collection media in the form of synthetic beads carrying mineral particles. Thus, each of the synthetic beads comprises an open-network structure or a three-dimensional open-cell structure made from a hydrophobic material which is a reaction product to an isocyanate and a polyol. The three-dimensional open-cell structure is hydrophobic and tacky for attracting or attaching one or more of the mineral particles to the molecules, causing the mineral particles to attach to synthetic beads. The apparatus also has a releasing stage configured to apply an interrupting force so as to remove the mineral particles from the synthetic beads. In this apparatus, the plurality of synthetic beads may be entirely made of the hydrophobic foam as disclosed herein or may have a body made of polymer, glass or ceramic and a surface layer made of the hydrophobic foam.
In effect, the present invention provides mineral separation techniques using synthetic beads made of the hydrophobic foam, including size-, weight-, density- and magnetic-based synthetic beads.
There may be a mixture of both air and lightweight synthetic beads. The lightweight synthetic beads may be used to lift the valuable material and the air may be used to create the desired froth layer in order to achieve the desired material grade.
A bead recovery process is also developed to enable the reuse of the lightweight synthetic beads in a closed loop process. This process may consist of a washing station whereby the valuable mineral is mechanically, chemically, thermally or electromagnetically removed from the lightweight beads or bubbles. In particular, the removal process may be carried out by way of controlling the pH value of the medium in which the enriched polymer beads or bubbles are embedded, controlling the temperature of the medium, applying mechanical or sonic agitation to the medium, illuminating the enriched polymer beads with light of a certain range of frequencies, or applying electromagnetic waves on the enriched polymer beads in order to weaken the bonds between the valuable material and the surface of the synthetic beads made of the hydrophobic foam, according to the present invention.
In all these embodiments, the synthetic beads are at least made of the hydrophobic three-dimensional open-cell structure which is a reaction product of an isocyanate and polyol.
Referring now to the drawing, which is not necessarily drawn to scale, the foregoing and other features and advantages of the present invention will be more fully understood from the following detailed description of illustrative embodiments, taken in conjunction with the accompanying drawing in which like elements are numbered alike:
The present invention provides a hydrophobic foam which can be used as synthetic beads, filters, conveyor belts or any collection substrates for attracting mineral particles in aa aqueous slurry. In particular, the hydrophobic foam is a reticulated foam, an open-network structure or three-dimensional open-cell structure made from a hydrophobic material, which is a reaction product of an isocyanate and a polyol.
As used herein, the reaction product of isocyanate and polyol described above having the open-network structure, reticulated structure or three-dimensional open-cell structure is also referred as the hydrophobic foam. The engineered collection medium made of the hydrophobic foam taken the form of a cube or sphere is also referred to as synthetic bead or polymer bubble. For example,
As described above in conjunction with
Open-cell foam or reticulated foam offers an advantage over non-open cell materials by having higher surface area to volume ratio. When the foam is made of the reaction product of an isocyanate and polyol, according to the present invention, it promotes attachment of mineral to the foam “network” enables higher mineral recovery rates and also improves recovery of less liberated mineral than conventional process. For example, the open cells in an engineered foam block allow passage of fluid and particles smaller than the cell size but captures mineral particles that come in contact with the open cells. This also allows the selection of cell size dependent upon slurry properties and application.
According to some embodiments of the present invention, the engineered collection media take the form of an open-cell foam/structure in a rectangular block or a cubic shape 70a as illustrated in
According to some embodiments of the present invention, the engineered collection media may take the form of a filter 70b with a three-dimensional open-cell structure as shown in
According some embodiments of the present invention, the engineered collection media may take the form of a membrane 70c, a section of which is shown in
According some embodiments of the present invention, the engineered collection media may take the form of a membrane 70d, a section of which is shown in FIG. 10d. As seen in
In various embodiments of the present invention, the engineered collection media as shown in
In some embodiments of the present invention, the solid phase body may have a core made from a material selected from, polyester urethane, polyether urethane, reinforced urethanes, PVC coated PV, silicone, polychloroprene, polyisocyanurate, polystyrene, polyolefin, polyvinylchloride, epoxy, latex, fluoropolymer, polypropylene, phenolic, EPDM, and nitrile. The solid-phase body has a hydrophobic surface layer made of the hydrophobic foam, according to the present invention.
In some embodiments of the present invention, the solid phase body may be modified with tackifiers, plasticizers, crosslinking agents, chain transfer agents, chain extenders, adhesion promoters, aryl or alky copolymers, fluorinated copolymers, hexamethyldisilazane, silica or hydrophobic silica.
In some embodiments of the present invention, the solid phase body may include a core made of a material selected from acrylics, butyl rubber, ethylene vinyl acetate, natural rubber, nitriles; styrene block copolymers with ethylene, propylene, and isoprene, and polyvinyl ethers.
In some embodiments of the present invention, an adhesion agent may be provided between the solid phase body and the coating so as to promote adhesion between the core and the hydrophobic surface layer made of the hydrophobic foam.
In some embodiments of the present invention, the solid phase body may have a core made of plastic, ceramic, carbon fiber or metal, with a hydrophobic surface layer made of the hydrophobic foam, according to the present invention.
In some embodiments of the present invention, the three-dimensional open-cell structure may include pores ranging from 10-200 pores per inch.
In some embodiments of the present inventions, the engineered collection media may be encased in a cage structure that allows a mineral-containing slurry to pass through the cage structure so as to facilitate the contact between the mineral particles in slurry and the engineered collection media.
In some embodiments of the present invention, the cage structures or the filters carrying mineral particles may be removed from the processor so that they can be stripped of the mineral particles, cleaned and reused.
By way of example,
The flotation cell or column 12 may be configured with a top part or piping 22, e.g., having a valve 22a, to receive the pulp slurry or mixture 14 and also with a bottom part or piping 24 to receive the synthetic beads 70. In operation, the buoyancy of the synthetic beads 70 causes them to float upwardly from the bottom to the top of the flotation cell or column 12 through the pulp slurry or mixture 14 in the flotation cell or column 12 so as to collide with the water, valuable material and unwanted material in the pulp slurry or mixture 14. The hydrophobicity of the synthetic beads 70 causes them to attach to the valuable material in the pulp slurry or mixture 14. As being made of a hydrophobic foam, the synthetic beads 70 attract the valuable material to the surface structure, so that the valuable material is lifted through the cell or column 12 due to the buoyancy of the synthetic beads 70. As a result of the collision between the synthetic beads 70 and the water, valuable material and unwanted material in the pulp slurry or mixture 14, and the attachment of the synthetic beads 70 and the valuable material in the pulp slurry or mixture 14, the enriched synthetic beads 18 having the valuable material attached thereto will float to the top of the flotation cell 12 and form part of the froth formed at the top of the flotation cell 12. The flotation cell 12 may include a top part or piping 20 configured to provide the enriched synthetic beads 18 having the valuable material attached thereto, which may be further processed consistent with that set forth herein. In effect, the enriched synthetic beads 18 may be taken off the top of the flotation cell 12 or may be drained off by the top part or piping 20.
The flotation cell or column 12 may be configured to contain an attachment rich environment, including where the attachment rich environment has a high pH, so as to encourage the flotation recovery process therein. The flotation recovery process may include the recovery of ore particles in mining, including copper. The scope of the invention is not intended to be limited to any particular type or kind of flotation recovery process either now known or later developed in the future. The scope of the invention is also not intended to be limited to any particular type or kind of mineral of interest that may form part of the flotation recovery process either now known or later developed in the future.
According to some embodiments of the present invention, the synthetic beads 70 may be configured with a surface area flux by controlling some combination of the size of the polymer or polymer-based bubbles and/or the injection rate that the pulp slurry or mixture 14 is received in the flotation cell or column 12. The synthetic beads 70 may also be configured with a low density so as to behave like air bubbles. The synthetic beads 70 may also be configured with a controlled size distribution of medium that may be customized to maximize recovery of different feed matrixes to flotation as valuable material quality changes, including as ore quality changes.
According to some embodiments of the present invention, the flotation cell or column 12 may be configured to receive the synthetic beads 70 together with air, where the air is used to create a desired froth layer in the mixture in the flotation cell or column 12 in order to achieve a desired grade of valuable material. The synthetic beads 70 may be configured to lift the valuable material to the surface of the mixture in the flotation cell or column.
The apparatus 10 may also include piping 26 having a valve 26a for providing tailings to a thickener 28 configured to receive the tailings from the flotation cell or column 12. The thickener 28 includes piping 30 having a valve 30a to provide thickened tailings. The thickener 28 also includes suitable piping 32 for providing reclaimed water back to the flotation cell or column 12 for reuse in the process. Thickeners like element 28 are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind either now known or later developed in the future.
According to some embodiments of the present invention, the apparatus 10 may further include a bead recovery process or processor generally indicated as 50 configured to receive the enriched synthetic beads 18 and provide reclaimed synthetic beads 52 without the valuable material attached thereon so as to enable the reuse of the synthetic beads 52 in a closed loop process. By way of example, the bead recovery process or processor 50 may take the form of a washing station whereby the valuable mineral is mechanically, chemically, or electro-statically removed from the enriched synthetic beads 18.
The bead recovery process or processor 50 may include a releasing apparatus in the form of a second flotation cell or column 54 having piping 56 with a valve 56a configured to receive the enriched synthetic beads 18; and substantially release the valuable material from the synthetic beads 18, and also having a top part or piping 57 configured to provide the reclaimed synthetic beads 52, substantially without the valuable material attached thereon The second flotation cell or column 54 may be configured to contain a release rich environment, including where the release rich environment has a low pH, or including where the release rich environment results from ultrasonic waves pulsed into the second flotation cell or column 54.
The bead recovery process or processor 50 may also include piping 58 having a valve 56a for providing concentrated minerals to a thickener 60 configured to receive the concentrated minerals from the flotation cell or column 54. The thickener 60 includes piping 62 having a valve 62a to provide thickened concentrate. The thickener 60 also includes suitable piping 64 for providing reclaimed water back to the second flotation cell or column 54 for reuse in the process. Thickeners like element 60 are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind either now known or later developed in the future.
Embodiments are also envisioned in which the enriched synthetic beads are placed in a chemical solution so the valuable material is dissolved off, or are sent to a smelter where the valuable material is burned off, including where the synthetic beads are reused afterwards.
In operation, the collision technique causes vortices and collisions using enough energy to increase the probability of touching of the synthetic beads 206 and the valuable material in the mixture 202, but not too much energy to destroy bonds that form between the synthetic beads 206 and the valuable material in the mixture 202. Pumps, not shown, may be used to provide the mixture 202 and the synthetic beads 206 are the appropriate pressure in order to implement the collision technique.
By way of example, the first device 210 and the second device 212 may take the form of shower-head like devices having a perforated nozzle with a multiplicity of holes for spraying the mixture and the synthetic beads towards one another. As a result of the collision between the synthetic beads 206 and the mixture, enriched synthetic beads having the valuable material attached thereto will float to the top and form part of the froth in the flotation cell 201. The flotation cell 201 may include a top part or piping 214 configured to provide enriched synthetic beads 216 having the valuable material attached thereto, which may be further processed consistent with that set forth herein.
The alternative apparatus 200 may be used in place of the flotation columns or cells, and inserted into the apparatus or system shown in
Various embodiments of the present invention are envisioned as examples to show that the valuable minerals can be mechanically, chemically, thermally, optically or electromagnetically removed or released from the enriched synthetic beads.
By way of example, the bead recovery process or processor 50 as shown in
When ultrasonic waves are applied in a solution or mixture containing the enriched synthetic beads, they can cause the attached mineral particles to move rapidly against the surface of the synthetic beads, thereby shaking the mineral particles loose from the surface. It is known that ultrasound is a cyclic sound pressure with a frequency greater than the upper limit of human hearing. Thus, in general, ultrasound goes from just above 20 kilohertz (KHz) all the way up to about 300 KHz. In ultrasonic cleaners, low frequency ultrasonic cleaners have a tendency to remove larger particle sizes more effectively than higher operational frequencies. However, higher operational frequencies tend to produce a more penetrating scrubbing action and to remove particles of a smaller size more effectively. In mineral releasing applications involving mineral particles finer than 100 μm to 1 mm or larger, according to some embodiments of the present invention, the ultrasonic wave frequencies range from 10 Hz to 10 MHz. By way of example, the bead recovery process or processor 50 as shown in
In physisorption, the valuable minerals are reversibly associated with the synthetic bubbles or beads, attaching due to electrostatic attraction, and/or van der Waals bonding, and/or hydrophobic attraction, and/or adhesive attachment. The physisorbed mineral particles can be desorbed or released from the surface of the synthetic beads if the pH value of the solution changes. Furthermore, the surface chemistry of the most minerals is affected by the pH. Some minerals develop a positive surface charge under acidic conditions and a negative charge under alkaline conditions. The effect of pH changes is generally dependent on the collector and the mineral collected. For example, chalcopyrite becomes desorbed at a higher pH value than galena, and galena becomes desorbed at a higher pH value than pyrite. If the valuable mineral is collected at a pH of 8 to 11, it is possible to weaken the bonding between the valuable mineral and the surface of the synthetic beads by lower the pH to 7 and lower. However, an acidic solution having a pH value of 5 or lower would be more effective in releasing the valuable mineral from the enriched synthetic beads. According to one embodiment of the present invention, the bead recovery process or processor 50 as shown in
In general, the pH value is chosen to facilitate the strongest attachment, and a different pH value is chosen to facilitate release. Thus, according to some embodiments of the present invention, one pH value is chosen for mineral attachment, and a different pH value is chosen for mineral releasing. The different pH could be higher or lower, depending on the specific mineral and collector.
The physisorbed mineral particles can be desorbed or released from the surface of the synthetic beads if a surface active agent is introduced which interferes with the attachment of the mineral particles and the bead surface. In one embodiment, when the surface active agent is combined with mechanical energy, the particle easily detaches from the surface.
More than one way can be used to interrupt the attachment of the mineral particles to the synthetic beads electromagnetically. For example, it is possible to use microwaves to heat up the enriched synthetic beads and the water in the flotation column. Thus, it is possible to provide a microwave source where the enriched synthetic bubbles are processed. By way of example, the bead recovery process or processor 50 as shown in
When the enriched synthetic bubbles or beads are densely packed such that they are in a close proximity to each other, the rubbing action among adjacent synthetic bubbles or beads may cause the mineral particles attached to the enriched synthetic beads to be detached. By way of example, the bead recovery process or processor 50 as shown in
A heater like element 150 (
More than one of the methods for releasing the valuable material from the enriched synthetic beads can be used in the same bead recovery process or processor at the same time. For example, while the enriched synthetic beads 18 are subjected to ultrasonic agitation (see
According to some embodiments of the present invention, the separation process can be carried out in a horizontal pipeline as shown in
By way of example,
The first processor 402 may take the form of a first chamber, tank, cell or column that contains an attachment rich environment generally indicated as 406. The first chamber, tank or column 402 may be configured to receive the mixture or pulp slurry 401 in the form of fluid (e.g., water), the valuable material and the unwanted material in the attachment rich environment 406, e.g., which has a high pH, conducive to attachment of the valuable material. The second processor 404 may take the form of a second chamber, tank, cell or column that contains a release rich environment generally indicated as 408. The second chamber, tank, cell or column 404 may be configured to receive, e.g., water 422 in the release rich environment 408, e.g., which may have a low pH or receive ultrasonic waves conducive to release of the valuable material. Alternatively, a surfactant may be used in the release rich environment 408 to detach the valuable material from the conveyor belt 420 under mechanical agitation or sonic agitation, for example. Sonic agitation can be achieved by a sonic source such as the ultrasonic wave producer 164 as shown in
In operation, the first processor 402 may be configured to receive the mixture or pulp slurry 401 of water, valuable material and unwanted material and the conveyor belt 420 that may be configured to attach to the valuable material in the attachment rich environment 406. In
The first processor 402 may also be configured to provide drainage from piping 441 of, e.g., tailings 442 as shown in
By way of example,
The first processor 502 may take the form of a first chamber, tank, cell or column that contains an attachment rich environment which has a high pH, conducive to attachment of the valuable material. The second processor 504 may take the form of a second chamber, tank, cell or column that contains a release rich environment which may have a low pH or receive ultrasonic waves conducive to release of the valuable material. Alternatively, the second process 504 may be configured as a stripping tank where a surfactant is used to release the valuable material from the filter 522 under mechanical agitation or sonic agitation, for example.
The first processor 502 may also be configured to provide drainage from piping 541 of, e.g., tailings 542 as shown in
The first processor 502′ may also be configured with piping 580 and pumping 280 to recirculate the tailings 542 back into the first processor 502′. The scope of the invention is also intended to include the second processor 504′ being configured with corresponding piping and pumping to recirculate the concentrate 562 back into the second processor 504′.
According to some embodiments of the present invention, the engineered collection media as shown in
As seen in
The engineered collection media in the form of cubes or spheres used in mineral separation are referred herein as synthetic beads. As shown in
The term “polymer bubbles or beads”, and the term “synthetic bubbles” are used interchangeably.
Surface area is an important property in the mineral recovery process because it defines the amount of mass that can be captured and recovered. High surface area to volume ratios allows higher recovery per unit volume of media added to a cell. As illustrated in
The hydrophobic foam may be cut in a variety of shapes and forms. For example, a hydrophobic foam belt can be moved through the slurry to collect the desired minerals and then cleaned to remove the collected desired minerals. The cleaned foam belt can be reintroduced into the slurry. Strips, blocks, and/or sheets of foam of varying size can also be used where they are randomly mixed along with the slurry in a mixing cell. The thickness and cell size of a foam can be dimensioned to be used as a cartridge-like filter which can be removed, cleaned of recovered mineral, and reused.
As mentioned earlier, the open cell or reticulated foam made with the hydrophobic foam offers an advantage over other media shapes such as sphere by having higher surface area to volume ratio. Surface area is an important property in the mineral recovery process because it defines the amount of mass that can be captured and recovered. High surface area to volume ratios allows higher recovery per unit volume of media added to a cell.
The open cell or reticulated foam provides three-dimensional open network structures having high surface area with extensive interior surfaces and tortuous paths protected from abrasion and premature release of attached mineral particles. This provides for enhanced collection and increased functional durability. Without a coating, the hydrophobic foam conveyor belts or filters could last longer.
The use of the reaction product of an isocyanate and polyol promotes attachment of mineral to the foam “network” enables higher recovery rates and improved recovery of less liberated mineral when compared to the conventional process. This foam is open-cell structure so it allows passage of fluid and unattracted particles smaller than the cell size but captures mineral bearing particles the come in contact with the collection surfaces. Selection of cell size is dependent upon slurry properties and application.
A three-dimensional open cellular structure optimized to provide a compliant, tacky surface of low energy enhances collection of hydrophobic or hydrophobized mineral particles ranging widely in particle size. This structure may include, or take the form of, open-cell foam with a compliant, tacky surface of low surface energy.
The structure may be in the form of sheets, cubes, spheres, or other shapes as well as densities (described by pores per inch and pore size distribution), and levels of tortuosity that optimize surface access, surface area, mineral attachment/detachment kinetics, and durability. These structures may be additionally optimized to target certain mineral particle size ranges, with denser structures acquiring smaller particle sizes. In general, cellular densities may range from 10-200 pores per inch, more preferably 10-90 pores per inch, and most preferably 20-60 pores per inch.
The specific shape or form of the structure may be selected for optimum performance for a specific application. For example, the structure may be cut in a variety of shapes and forms. For example, a hydrophobic foam belt could be moved through the slurry removing the desired mineral whereby it is cleaned and reintroduced into the slurry. Strips, blocks, and/or sheets of hydrophobic foam of varying size could also be used where they are randomly mixed along with the slurry in a mixing cell. Alternatively, a conveyor structure may be formed where the foam is encased in a cage structure that allows a mineral-containing slurry to pass through the cage structure to be introduced to the underlying foam structure where the mineral can react with the foam and thereafter be further processed in accordance with the present invention. The thickness and cell size could be changed to a form cartridge like filter whereby the filter is removed, cleaned of recovered mineral, and reused.
There are numerous characteristics of the foam that may be important and should also be considered, as follows:
Mechanical durability: Ideally, the foam will be durable in the mineral separation process. For example, a life of over 30,000 cycles in a plant system would be beneficial. Without a coating, a conveyor belt, synthetic bead or a filter may have a significant advantage in medium durability and lifetime.
Surface area: Higher surface area provides more sites for the mineral to the surface of the foam substrate. There is a tradeoff between larger surface area (for example using small pore cell foam) and ability of the hydrophobic foam structure to capture mineral while allowing gangue material to pass through and not be capture, for example due to a small cell size that would effectively entrap gangue material. The foam size is selected to optimize capture of the desired mineral and minimize mechanical entrainment of undesired gangue material.
Cell size distribution: Cell diameter needs to be large enough to allow gangue and mineral to be removed but small enough to provide high surface area. There should be an optimal cell diameter distribution for the capture and removal of specific mineral particle sizes.
Tortuosity: Cells that are perfectly straight cylinders have very low tortuosity. Cells that twist and turn throughout the foam have “tortuous paths” and yield foam of high tortuosity. The degree of tortuosity may be selected to optimize the potential interaction of a mineral particle with the foam substrate, while not be too tortuous that undesirable gangue material in entrapped by the foam substrate.
The pore size (pores per inch (PPI)) of the foam is an important characteristic which can be leveraged to improved mineral recovery and/or target a specific size range of mineral. As the PPI increases the specific surface area (SSA) of the foam also increases. A high SSA presented to the process increases the probability of particle contact which results in a decrease in required residence time. This in turn, can lead to smaller size reactors. At the same time, higher PPI foam acts as a filter due to the smaller pore size and allows only particles smaller than the pores to enter into its core. This enables the ability to target, for example, mineral fines over coarse particles or opens the possibility of blending a combination of different PPI foam to optimize recovery performance across a specific size distribution.
The scope of the invention is described in relation to mineral separation, including the separation of copper from ore. It should be understood that the synthetic beads according to the present invention, are also configured for use in oilsands separation—to separate bitumen from sand and water in the recovery of bitumen in an oilsands mining operation. Likewise, the filters and membranes, according to some embodiments of the present invention, are also configured for oilsands separation. According to some embodiments of the present invention, the surface of a synthetic bead has a layer of hydrophobic foam, according to the present invention.
The scope of the invention is intended to include other types or kinds of applications either now known or later developed in the future, e.g., including a flotation circuit, leaching, smelting, a gravity circuit, a magnetic circuit, or water pollution control.
This application is also related to a family of nine PCT applications, which were all concurrently filed on 25 May 2012, as follows:
PCT application no. PCT/US12/39528 (Atty docket no. 712-002.356-1), entitled “Flotation separation using lightweight synthetic bubbles and beads;” PCT application no. PCT/US12/39524 (Atty docket no. 712-002.359-1), entitled “Mineral separation using functionalized polymer membranes;”
PCT application no. PCT/US12/39540 (Atty docket no. 712-002.359-2), entitled “Mineral separation using sized, weighted and magnetized beads;”
PCT application no. PCT/US12/39576 (Atty docket no. 712-002.382), entitled “Synthetic bubbles/beads functionalized with molecules for attracting or attaching to mineral particles of interest,” which corresponds to U.S. Pat. No. 9,352,335, which discloses solid beads, belts and filters, but not open-network structures;
PCT application serial no. PCT/US12/39591 (712-2.383-1/CCS-0090), entitled “Method and system for releasing mineral from synthetic bubbles and beads,” filed 25 May 2012, which itself claims the benefit of U.S. Provisional Patent Application No. 61/489,893, filed 25 May 2011, and U.S. Provisional Patent Application No. 61/533,544, filed 12 Sep. 2011, which corresponds to co-pending U.S. patent application Ser. No. 14/117,912, filed 15 Nov. 2013;
PCT application no. PCT/US/39596 (Atty docket no. 712-002.384), entitled “Synthetic bubbles and beads having hydrophobic surface;”
PCT application no. PCT/US/39631 (Atty docket no. 712-002.385), entitled “Mineral separation using functionalized filters and membranes,” which corresponds to U.S. Pat. No. 9,302,270;”
PCT application no. PCT/US12/39655 (Atty docket no. 712-002.386), entitled “Mineral recovery in tailings using functionalized polymers;” and
PCT application no. PCT/US12/39658 (Atty docket no. 712-002.387), entitled “Techniques for transporting synthetic beads or bubbles In a flotation cell or column,” all of which are incorporated by reference in their entirety.
This application also related to PCT application no. PCT/US2013/042202 (Atty docket no. 712-002.389-1/CCS-0086), filed 22 May 2013, entitled “Charged engineered polymer beads/bubbles functionalized with molecules for attracting and attaching to mineral particles of interest for flotation separation,” which claims the benefit of U.S. Provisional Patent Application No. 61/650,210, filed 22 May 2012, which is incorporated by reference herein in its entirety.
This application is also related to PCT/US2014/037823, filed 13 May 2014, entitled “Polymer surfaces having a siloxane functional group,” which claims benefit to U.S. Provisional Patent Application No. 61/822,679 (Atty docket no. 712-002.395/CCS-0123), filed 13 May 2013, as well as U.S. patent application Ser. No. 14/118,984 (Atty docket no. 712-002.385/CCS-0092), filed 27 Jan. 2014, and is a continuation-in-part to PCT application no. PCT/US12/39631 (712-2.385//CCS-0092), filed 25 May 2012, which are all hereby incorporated by reference in their entirety.
This application also related to PCT application no. PCT/US13/28303 (Atty docket no. 712-002.377-1/CCS-0081/82), filed 28 Feb. 2013, entitled “Method and system for flotation separation in a magnetically controllable and steerable foam,” which is also hereby incorporated by reference in its entirety.
This application also related to PCT application no. PCT/US16/57334 (Atty docket no. 712-002.424-1/CCS-0151), filed 17 Oct. 2016, entitled “Opportunities for recovery augmentation process as applied to molybdenum production,” which is also hereby incorporated by reference in its entirety.
This application also related to PCT application no. PCT/US16/37322 (Atty docket no. 712-002.425-1/CCS-0152), filed 17 Oct. 2016, entitled “Mineral beneficiation utilizing engineered materials for mineral separation and coarse particle recovery,” which is also hereby incorporated by reference in its entirety.
This application also related to PCT application no. PCT/US16/62242 (Atty docket no. 712-002.426-1/CCS-0154), filed 16 Nov. 2016, entitled “Utilizing engineered media for recovery of minerals in tailings stream at the end of a flotation separation process,” which is also hereby incorporated by reference in its entirety.
This application is related to PCT application serial no. PCT/US16US/68843 (Atty docket no. 712-002.427-1/CCS-0157), entitled “Tumbler cell form mineral recovery using engineered media,” filed 28 Dec. 2016, which claims benefit to Provisional Application No. 62/272,026, entitled “Tumbler Cell Design for Mineral Recovery Using Engineered Media”, filed 28 Dec. 2015, which are both incorporated by reference herein in their entirety.
It should be further appreciated that any of the features, characteristics, alternatives or modifications described regarding a particular embodiment herein may also be applied, used, or incorporated with any other embodiment described herein. It should be noted that the engineered collection media having the open-cell structure as shown in
This application claims the benefit of U.S. Provisional Application No. 62/627,266, filed 7 Feb. 2018, which is incorporated by reference herein in its entirety. This application is also related to patent application Ser. No. 15/401,755, filed 9 Jan. 2017 (WFMB/CiDRA nos. 712-002.428-2//CCS-0158/0175), which claims benefit to U.S. Provisional Application No. 62/276,051 (WFMB/CiDRA nos. 712-002.428//CCS-0158), filed 7 Jan. 2016, and U.S. Provisional Application No. 62/405,569 (WFMB/CiDRA nos. 712-002.439//CCS-0175), filed 7 Oct. 2016, which are all incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/017003 | 2/7/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62627266 | Feb 2018 | US |
