WO2015114505A1

WO2015114505A1 - Wear protection for flotation machine and method of making and using the same

Info

Publication number: WO2015114505A1
Application number: PCT/IB2015/050576
Authority: WO
Inventors: Shane MCLOUGHLIN; Rod STEAD
Original assignee: Flsmidth A/S
Priority date: 2014-01-28
Filing date: 2015-01-26
Publication date: 2015-08-06

Abstract

A flotation machine may include one or more components that are formed from an insert that is coated in a material such as a polymeric material or an elastomeric material. Portions of the components that have a high wear zone may be formed so that a ceramic material or other armoring material is bonded to the high wear zone area of the element. For instance, an armoring component may be positioned in a mold at a high wear zone area of an insert of the component. The polymeric or elastomeric material may then be poured into a mold for coating the insert and bonding the armoring component to the insert. Components that may be so formed or used may include, for example, stators, rotors, hoods, or draft tube collars of a flotation machine.

Description

WEAR PROTECTION FOR FLOTATION MACHINE AND METHOD OF MAKING AND USING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

This international application claims the benefit of United States Provisional Patent Application No. 61/932,461 filed on January 28, 2014. The contents of this application are hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present invention relates to flotation machines. More particularly, the present invention relates to stators, rotors, draft tubes, hoods and other flotation machine components that may be used in flotation machines and a method of forming such components of flotation machines for use in making a flotation machine.

BACKGROUND OF THE INVENTION

The flotation machines are used to separate valuable material such as minerals from material having little or no value by means of changes in the surface chemistry of solid particles in a slurry so that certain particles become hydrophobic or hydrophilic. Examples of flotation machines may be appreciated from U.S. Patent Nos.7,441,662, 5,205,9264, 4,800,017, 4,425,232 and 2,973,095, and International Publication Nos. WO 2013/067343, WO 2012/090167, WO 2012/088228, WO 2011/069314 and WO 2011/066705. Flotation machines are typically configured to retain a slurry, or pulp, within a tank. The slurry may include a material that is desired to be extracted from finely sized particles within the liquid of the slurry.

Often, flotation machines utilize a rotor positioned adjacent a stator. The rotor is rotated to agitate the slurry. Bubbles may be formed by agitation of the slurry and the feeding of air into the slurry to cause a froth to form above of the slurry. The hydrophobic particles will attach to the bubbles being carried to the top of the tank of the flotation cell where a froth is formed. The froth and particles suspended in the froth are collected by launders positioned adjacent to the top of the flotation cell.

I have determined that it would be desirable to design a flotation machine such that different components of the flotation machine may have a substantially more resistant to wear so that those elements have a longer life of usability and are configured to contribute to maintaining the performance of the machine over a longer period of time than conventional flotation machines.

SUMMARY OF THE INVENTION

A flotation machine can comprise a tank, a rotor for rotating in the tank to facilitate froth formation in the tank that has a plurality of blades, and a stator positioned in the tank adjacent the rotor. At least one of the rotor, the stator, a draft tube positioned below the rotor and a hood positioned above the rotor is comprised of a polymeric material or an elastomeric material and has at least one cover member attached thereto.

The cover member may be composed of a material that is harder than the polymeric material or an elastomeric material. For instance, the polymeric material or elastomeric material may be polyurethane, a urethane material, or other thermoplastic material or a rubber such as urethane rubber, natural rubber, neoprene rubber, MOR rubber, or nitrile rubber (NBR). Each cover member may be composed of a ceramic material such as siliconized silicon carbide, zirconia toughened aluminum, silicon nitride, zirconia, or alumina oxide. Each cover member may be configured as a sleeve, an annular structure, or be structured to define at least one aperture having a pre-specified shape for mating with a portion of a component of the flotation machine such as a rotor blade, portion of a rotor, vane of a stator, portion of a hood, or portion of a draft tube collar.

In some embodiments, the rotor can be covered with the polymeric material or the elastomeric material and there may be a plurality of cover members attached to the rotor. A respective one of the cover members can be attached to a respective one of the blades of the rotors such that the polymeric or elastomeric material is between the cover member and the blade to which that cover member is attached. The polymeric or elastomeric material can be between each cover member and an insert of the blade of the rotor to attach the cover member to the blade of the rotor.

Alternatively, or in addition, the stator can also be covered with the polymeric material or the elastomeric material a plurality of the cover members can be attached to the stator. Each vane of the stator can be attached to at least one respective cover member such that the polymeric or elastomeric material covering that vane is between an insert of the vane and the cover member. In some embodiments, the stator may be sized and configured as a disperser having a plurality of holes that is also covered with the polymeric material or the elastomeric material, and a plurality of the cover members may be attached to the disperser adjacent the holes of the disperser to cover portions of the disperser that define at least some of the holes of the disperser. The cover members can be attached to the disperser such that the polymeric or elastomeric material is between an insert of the disperser and the cover members. If no insert is used, the cover members may be attached to the polymeric or elastomeric material that forms the disperser to cover the portions of the disperser that define the holes. It is contemplated that a portion of the disperser may initially cover the cover members, but during operation that material may wear away quickly to expose the cover members thereafter during use of the flotation machine having such a disperser.

A collar of the draft tube can also be covered with the polymeric material or the elastomeric material or be formed of such material. The draft tube can have an inlet for receiving slurry and an outlet for outputting slurry adjacent the rotor. At least one cover member can be attached to the draft tube collar such that each cover member covers the polymeric or elastomeric material of the collar at a location at which the cover member is attached. Each cover member can be comprised of a ceramic material that is harder than the polymeric or elastomeric material.

The flotation machine can include a hood positioned in the tank above the rotor that has a plurality of holes and is comprised of the polymeric material or the elastomeric material. A plurality of the cover members may be attached to the hood adjacent the holes to cover portions of the hood that define at least some of the holes of the hood. Each of the cover members can be being comprised of a ceramic material that is harder than the polymeric material or the elastomeric material of the hood.

Some embodiments of the flotation machine may include a rotor, hood, stator and draft tube collar that all include one or more collar members attached thereto to cover a portion of an elastomeric or polymeric material covering that element or forming the body of that element. In other embodiments, only a subset of these elements may include one or more cover members. For instance, only the rotor and hood, rotor and stator, draft tube collar and stator, may include such cover members. As yet another example, only the hood, rotor and stator may each include one or more cover members or only the stator, hood and draft tube collar may include one or more cover members. Of course, numerous other combinations of different flotation machine elements may include one or more cover members can be utilized in other embodiments of the flotation machine.

A method of making a component of a flotation machine can include the steps of determining at least one location of wear for the component that is at a location at which the wear for the component is greater as compared to other portions of the component when the component is in use during operation of the flotation machine, placing at least one cover member in a mold that is at a position that corresponds to the determined at least one location of the component at which the wear for the component is greater as compared to other portions of the component when the component is in use during operation of the flotation machine, and feeding polymeric material or elastomeric material into the mold for forming the component and for bonding the at least one cover member to the formed component.

It should be appreciated that the component of the flotation machine can a rotor, a stator, a disperser, a hood, and a draft tube. Each of the at least one cover member may be composed of a ceramic material such as zirconia toughened alumina, zirconia, silicon nitride, siliconized silicon carbide, or alumina oxide that is harder than the polymeric material or elastomeric material. Each cover member may be configured as a sleeve, an annular structure or be structured to define an aperture having a pre-specified shape for mating with a portion of a component of the flotation machine.

The method may also include additional steps. For instance, the method may include the step of curing the component after the polymeric material or elastomeric material is fed into the mold. As another example, the method can also include the steps of positioning an insert into the mold and installing the component in the flotation machine. Each cover member may be positioned adjacent an insert prior to the polymeric material or elastomeric material being fed into the mold. The insert, the polymeric material or elastomeric material, and each cover member may be heated to a pre-specified temperature for a predetermined amount of time for curing prior to the installing of the component in the flotation machine.

Prior to the placing each cover member in the mold that is at the position that corresponds to a respective determined location of the component at which the wear for the component is greater as compared to other portions of the component when the component is in use of the flotation machine during operation of the flotation machine, the method can also include at least the step of cold bonding rubber material to a metal insert to at least partially cover the metal insert.

The feeding of the polymeric material or the elastomeric material into the mold to form the component and to bond the at least one cover member to the formed component can include: positioning strips of uncured rubber material adjacent the at least one cover member in the mold. As another alternative, the feeding of polymeric or elastomeric material into the mold can include pouring the material into the mold, such as pouring a molten polymeric material into the mold or pouring a heated polymeric material into the mold. Pressure and heat can be applied to the mold to form the component and to bond the at least one cover member to the formed component.

Other details, objects, and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof and certain present preferred methods of practicing the same proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments of flotation machines, draft tubes, hoods, stators, rotors, and other components of a flotation machine are shown in the accompanying drawings and certain exemplary methods of practicing the same are also illustrated therein. It should be understood that like reference numbers used in the drawings may identify like components.

Figure 1 is a perspective view of a first exemplary embodiment of a flotation machine having a portion of the machine cut away to illustrate the rotor, stator, draft tube, and hood of the machine.

Figure 2 is a perspective view of a second exemplary embodiment of a flotation machine having a portion of the machine cut away to illustrate the rotor, stator, draft tube, and hood of the machine.

Figure 3 is a perspective view of a third exemplary embodiment of a flotation machine having a portion of the tank wall of the machine cut away to illustrate the rotor and stator of the machine.

Figure 4 is a perspective view of an exemplary embodiment of a draft tube that may be utilized in the first, second, or third exemplary embodiments of the flotation machine.

Figure 5 is a perspective view of an exemplary embodiment of a hood that may be utilized in the first, second, or third exemplary embodiments of the flotation machine.

Figure 6 is a perspective view of an exemplary embodiment of a stator, or disperser, that may be utilized in the first, second, or third exemplary embodiments of the flotation machine.

Figure 7 is a perspective view of an exemplary embodiment of a stator that may be utilized in the first, second, or third exemplary embodiments of the flotation machine.

Figure 8 is a perspective view of an exemplary embodiment of a rotor that may be utilized in the first, second, or third exemplary embodiments of the flotation machine. Figure 9 is a perspective view of an exemplary embodiment of a rotor that may be utilized in the first, second, or third exemplary embodiments of the flotation machine.

Figure 10 is a perspective view of an exemplary embodiment of an insert, or frame, of a rotor that may be utilized in the first, second, or third exemplary embodiments of the flotation machine.

Figure 11 is a perspective view of an exemplary embodiment of a ceramic cover member that may be utilized in embodiment of the first, second, or third exemplary embodiments of the flotation machine.

Figure 12 is a perspective view of an exemplary embodiment of a ceramic cover member that may be utilized in embodiment of the first, second, or third exemplary embodiments of the flotation machine.

Figure 13 is a flow chart illustrating a method of making a component of a flotation machine that includes multiple ceramic cover members bonded to an insert of a flotation machine component (e.g. rotor, stator, draft tube, or hood) via a polymeric or elastomeric material that is used to cover the entirety of the insert and is bonded between the ceramic cover members and the insert.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring to Figures 1-12, a flotation machine 1 may include an agitation mechanism 2 that may include a rotor 5 that is rotated via a drive system 7. The drive system may include a motor such as an electric motor. The rotor 5 may have a plurality of blades and be rotated within a central opening defined by a stator 4. The stator 4 may be affixed to the floor 3a of the tank 3 or may be otherwise positioned in the tank 3 such that the rotor 5 is rotatable relative to the stator 4 to agitate slurry retained in the tank 3. The rotor 5 may also dissipate the air or other type of gas that is introduced into the tank via one or more apertures 5c formed in the rotor 5, openings formed in the stator 4 or apertures formed in both the stator and rotor that are in communication with a feed of air.

It should be understood that the flotation machine 1 may include one cell having just one tank or may include a plurality of cells defined by a plurality of tanks. Each cell of the flotation machine may include a tank 3, a rotor 5, a drive system 7 for rotating the rotor 5, and a stator 4, which may also be referred to as a disperser.

The tank may retain a slurry, or pulp, which may include a liquid along with solid particulates that contain a desired material to which an operator of the flotation machine may want to extract or recover. The agitation of the slurry and gas may be configured to generate bubbles for forming a froth above the slurry. Air may be passed into the tank via an air intake that feeds air through a channel formed in a shaft that rotates to rotate the rotor 5 to an outlet adjacent to the blades 5a of the rotor. The outlet may include one outlet that emits air below the rotor 5 or may include a plurality of apertures 5c that emit air out of the rotor 5 between blades 5a of the rotor. Bubbles may be generated by the air fed into the tank and agitation caused by the rotating rotor to generate a froth. For example, the agitation of the fluid via the rotor may facilitate the attachment of formed bubbles to hydrophobic particles within the slurry. The bubbles may carry those attached particles to a froth zone formed on the top of the floatation machine located above the slurry so that the particulates may be recovered from the slurry such as via one or more launders or other types of particulate extraction devices, particulate removal devices, or froth extraction devices positioned adjacent to the tank.

In other embodiments, no air may be fed via an air feeding mechanism that may pump or push air through a shaft that rotates to rotate the rotor 5 for feeding air into the slurry. Rotation of the rotor 5 may draw particles and liquid of the slurry through a standpipe and out of the draft tube for forming a froth and having solid particulates become entrained in bubbles that pass through the slurry to from a froth at the top of the tank. Air may be naturally pulled into bubble formation from above the top of the tank and no supplemental air may be otherwise pushed into the slurry via a separate air feed mechanism.

A draft tube 9 may include a collar at its upper terminal end portion that is positioned below the rotor 5. The draft tube collar may be positioned so that the outside of the rotor is engaged with the inside diameter of the draft tube collar. For instance, the blades of the rotor may be very close to the inner wall of the draft tube collar that may define an opening in which the lower portion of the rotor is positioned. The draft tube 9 may be configured to have an inlet opening adjacent the floor 3a of the tank and an outlet opening that is adjacent the bottom of the rotor 5. Rotation of the rotor 5 may create a pressure differential that drives movement of the solid particulates of the slurry near the floor 3a of the tank into the draft tube 9 and out of the outlet of the draft tube 9 adjacent the rotor 5 so that the particulates of the slurry are mixed with bubbles formed via the air being fed into the tank. The rotation of the rotor 5 can help facilitate the attachment of particulates to the bubbles for capture of desired material from the slurry.

The stator 4 may include vanes 4a that are spaced apart to define openings.

Alternatively, the stator 4 may be configured as a disperser and include a plurality of holes, such as oval shaped holes, circular holes, or holes having another type of shape. The openings or holes of the stator may help distribute the bubbles formed via the agitation mechanism of the flotation machine throughout the tank in a pre-specified profile. In some embodiments, a hood 11 may also be positioned in the tank. The hood 11 may be positioned above the stator 4 and rotor 5 and have holes or other openings that are circular, oval, or otherwise shaped to further facilitate the distribution of bubbles for a formation of froth within the tank.

Wear zones for different components of the flotation machine 1 may be identified. For instance, depending on the geometry of a given rotor 5, stator 4, hood 11 or draft tube 9 different portions of a rotor blade or stator vane, may be identified as experiencing substantially greater wear than other portions of those elements. For example, the top number of rows 4c of openings 4d in a stator 4 that is configured as a disperser as shown in Figures 2 and 6 may be identified as being portions of a stator that experience substantially greater wear than other portions of the stator 4. As another example, portions of vanes 4a of a stator 4 that define openings 4d in the stator 4 may be identified as experiencing greater wear than other locations of the stator or other portions of the vanes 4a of the stator. As yet another example, a middle portion or lower portion of a blade 5 a of a rotor 5 may be identified as experiencing greater wear than other portions of the rotor blade. Portions of a hood 11 that define outermost holes 1 lb may also be identified as experiencing greater wear than other inner holes 11a that are defined in the hood.

As yet another example, a draft tube collar 9a that is adjacent an outlet end 9b of the draft tube may be identified as experiencing greater wear than other portions of the draft tube 9, such as an inlet opening 9d or holes 9c adjacent the inlet opening 9d of the draft tube 9. The draft tube collar 9a may be configured to be adjacent to a bottom portion of the rotor 5 and may surround or enclose the bottom portion of the rotor 5.

The hood 11, draft tube 9, stator 4, and rotor 5 may each be formed so that the different wear zones that experience greater wear than other portions of those elements are provided with greater protection against wear. Each of those components of the flotation machine may be formed so that each has one or more covering members that are composed of a ceramic material or other material that may be configured to reduce the wear experienced by the portions that the covering members cover. Ceramic material that may be used to fabricate such cover members may be any of a number of suitable types of ceramic material, such as zirconia toughened alumina (ZTA), zirconia, or silicon nitride (N₄S1₃), siliconized silicon carbide (SiSiC) or alumina oxide (AI₂O₃), which may also be referred to as Alumina Ceramic. It is contemplated that other types of ceramic material may be used instead of ZTA, N₄S1₃, SiSiC, zirconia, or AI₂O₃ or that a non-ceramic material may be used such as a suitably hard metal or a suitably hard composite material.

Referring to the stators 4, ceramic sleeves, or covers 4b may be positioned to cover one or more discrete portions of the vanes 4a of the stators. As such, the covers may be generally U- shaped, generally V-shaped, or generally C-shaped covers, such as U-shaped, V-shaped, or C- shaped sleeves or cover members. If the stator 4 is configured as a disperser, ceramic covers 4b or other cover members may be configured as generally annular structures such as tubular structures or polygonally shaped annual structures that may cover the surfaces that define holes in the disperser. The ceramic covers may be positioned on the disperser so that they cover the holes in only an upper number of rows of holes in a disperser if the portions of the disperser that define those holes are expected to experience the most wear. The ceramic covers 4b or other cover members may be positioned to cover the portions of the vanes of the stator 4 that are configured to experience the most wear as compared to other portions of the stator 4.

Referring to rotors 5, the lower edge of the blades 5 a of the rotor may be the portion of the rotor that is expected to experience the most wear as compared to other portions of the rotor 5. As such, ceramic coverings 5b or other cover members may be positioned to cover those lower edges of the blades 5a. Alternatively, a middle portion, or multiple discrete portions of each rotor blade 5 a may be identified as experiencing the most wear for a given application. As such, those portions may be covered by ceramic coverings 5b. Each of the ceramic coverings 5b may be a sleeve that is generally U-shaped, generally C-shaped, generally V-shaped or is otherwise configured as a sleeve that receives a portion of the rotor blade 5a for being attached to that portion of the rotor blade for covering that portion of the rotor blade 5a.

Referring to the hood 11 , the portions of the hood that define the holes of the hood may be the portions of the hood that are identified as experiencing the most wear during operations of the flotation machine as compared to other portions of the hood 11. The outermost holes 11a may experience more wear than inner holes l ib. Alternatively, the innermost holes may be determined to experience more wear than the outermost holes. The portions of the hood that define those holes may be covered by ceramic coverings or other type of cover members, such as annular ceramic members that are generally tubular in shape, ring shaped structures, or annular polygonal structures may be positioned to cover the portions of the hood that define the holes. In some embodiments, only a limited number of rows of the outermost holes or innermost holes of the hood may include the ceramic covers, or sleeves.

Referring to the draft tube 9, the draft tube collar 9a may be identified as the portion of the draft tube that may experience the most wear as compared to other portions of the draft tube 9 during operations of the flotation machine. The draft tube collar 9a may be a portion of the draft tube the surrounds or encloses a bottom portion of the rotor 5, for example. The collar of the draft tube 9 may be covered via a cover member such as a ceramic covering sized as an annular shaped covering or a sleeve that is configured to cover an upper edge of the draft tube collar and at least an upper portion of the draft tube collar. The cover member may be configured to cover the inner circumference of the draft tube, or inner surface area of the draft tube, that faces a portion of the rotor that is positioned in or that is otherwise in engagement with that portion of the draft tube collar.

Referring to Figure 11, a sleeve or other cover member 15 that may be utilized for covering a vane or blade or other portion of a flotation machine component may include a body that has a first wall 15a, a second wall 15b, a third wall 15c, and a fourth wall 15d, that are each connected to each other to define a channel 15f for receiving a portion of an insert 16 of that component. In some embodiments, the cover member 15 may be integrally cast or otherwise formed so that all the walls are integral with each other. It should be appreciated that an embodiment of the cover member 15 may be stator vane covers 4b or rotor blade ceramic coverings 5b, or cover members attached to a draft tube collar, hood, or disperser. The insert 16 may be composed of metal, such as steel, aluminum, or other metal that is cast, formed, or otherwise fabricated into a shape of the component, such as the shape of a desired rotor 5, stator 4, draft tube 9 portion, or hood 11. At least one or more of the walls of the cover member 15 may include protrusions 15e, which may be ribs, teeth, projections, or other protruding elements having any of a number of possible shapes or sizes that protrude from one or more of the walls into the channel 15f that is sized to receive a portion of the insert 16. There may only be one protrusion or a plurality of protrusions extending from one or more walls of the cover member 15 and into the channel 15f defined by the walls of the cover member 15.

The cover members 15 may be positioned over the insert on the high wear zone locations for the component. For instance, an insert 16 may be placed in a mold and multiple cover members 15 may be positioned on the high wear zone locations of the insert for attachment to the insert at those locations. The locations on which the cover members 15 are placed on the insert may correspond with the high wear zone locations determined to exist for the formed component. Thereafter, the mold may be closed and heated and a heated polymeric material such as polyurethane, a urethane material, or other thermoplastic material may be poured into the mold or otherwise fed into the mold. The polymeric or elastomeric material that is used may be selected to prevent the covered component from corroding due to exposure to the materials within a flotation machine tank 3, helping to prevent wear of the component, and/or additionally meeting other design criteria. The material may then be heated for a predetermined amount of time while in the mold to maintain the temperature of the polymeric material or elastomeric material at a desired set point until that material has bonded to the insert and the cover members 15. Thereafter, the formed component may be taken out of the mold and placed in an oven or other curing device and heated at a pre-specified curing temperature for a pre-specified curing time until the component has cured sufficiently to ensure that the polymeric or elastomeric material has reached its optimal cured physical properties and that there is a sufficient bonding of the polymeric or elastomeric material to the insert 16 and cover members 15.

The protrusions 15e may be configured to facilitate the polymeric or elastomeric material being positioned between the insert and cover member 15 so that a sufficiently strong bond is formed between the insert 16 and cover member 15 via the polymeric or elastomeric material. The additional surface area provided by the protrusions 15e can help improve the strength of attachment between the insert 16 and cover member 15 so that the cover member 15 stays positioned on the component when installed in a flotation machine and used during operation of the flotation machine. During the molding process, the polymeric or elastomer material may cover an entirety of the insert or a substantial entirety of the insert 16. After the molding process is completed, the cover members 15 may be located on the exterior of the cured polymeric material or elastomeric material. In some embodiments of a component (e.g. a disperser, a draft tube collar, a rotor, or a hood), no insert may be included in the mold. Instead, the component may be formed by a polymeric material being inserted within a mold and formed. For embodiments of the component that do not include an insert (e.g. are formed of a polymeric or elastomeric material within the mold without use of a metal insert or skeleton), the cover members may be positioned in the mold prior to pouring or otherwise inserting in the polymeric material. The greater surface area provided by the protrusions 15e and the shape of apertures defined by those protrusions can help ensure that the cover member is strongly affixed to the formed component (e.g. a disperser, a draft tube collar, or a hood) when the component is molded or otherwise formed. In some embodiments, the polymeric material may completely cover the one or more cover members when the component is molded. When in use in a flotation machine, the polymeric material that covers the cover members may subsequently wear off the cover member so that the cover member is subsequently exposed on an exterior surface of the component and thereafter reinforces the component to improve the component' s resistance to wear.

In some alternative cover members, such as the cover member shown in Figure 12, a cover member may be generally cylindrical, hollow oval, or tubular in shape and have grooves or other apertures 15g formed therein that are configured to contact outer surfaces adjacent to holes of a structure such as a disperser or hood 11 that defines those holes. The generally cylindrical cover member may also include a central opening 15h or channel. The apertures 15g may help define protrusions or other projections for providing an increase surface area for facilitating a strong bond between the polymeric or elastomeric material of the component and the cover member. When attached to a structure, the outer surface of the cover member may be directly affixed to a polymeric or elastomeric component so that the central opening 15h may be the opening of the formed structure (e.g. a hood 11 or a disperser) through which slurry and/or bubbles pass due to rotation of a rotor 5 when that structure is installed within a flotation machine.

In some embodiments, the component (e.g. a stator, rotor, hood, disperser, or draft tube) may be formed of an elastomeric material such as rubber such as urethane rubber, natural rubber, neoprene rubber, MOR rubber, or nitrile rubber (NBR). When the elastomeric material is a rubber, the component may be formed differently than a polymeric molding process. For example, when the component is formed using an insert such as a metal insert or metal frame (e.g. a metal skeleton of a stator, a metal frame defining a rotor, a metal insert defining a portion of a hood or disperser), a cured rubber sheet may be cold bonded to the metal insert via glue or other type of adhesive material. Alternatively, strips of uncured rubber may be pressed into a mold or die that contains the insert having the cured rubber bonded thereto. One or more cover members may also be included in the mold with the strips of uncured rubber and the insert for attaching the ceramic cover members to the insert at locations that may correspond to

predetermined high wear experiencing locations for the component to be ultimately fabricated. The mold may then be pressed and heated so that a combination of heat and pressure cures the rubber and bonds the rubber and any cover members to the insert. A vulcanizing process may then be utilized to form the component. For example, strips of uncured rubber may be laid onto any exposed metal portions of the insert and into contact with other rubber coated portions of the component. One or more ceramic cover members may also be positioned adjacent the insert for bonding the one or more cover members to the insert via the vulcanization process. The rubber coated insert and any cover members may then be positioned in an autoclave and the part may then be cured by heat and pressure when in the autoclave. The one or more cover members positioned on the insert during the vulcanization process may also be bonded to the insert when the part is done curing.

In one embodiment, it is contemplated that different metal elements of a particular component may be formed and attached to one or more cover members and polymeric or elastomeric material. Thereafter, those different elements having the cover members and polymeric or elastomeric material may be fastened together to form a structure such as a rotor or stator. Any exposed metal that exists thereafter may then have further polymeric or elastomeric material positioned over the exposed metal and subsequently heated and pressed thereon to bond the polymeric or elastomeric material to the structure. One or more cover members may also be included in this phase for attaching one or more cover members to these other portions of the structure as well. The formed structure may subsequently be placed in an oven or other element to be maintained at a pre- specified temperature for a predetermined time for curing of the structure.

For example, a blade of a rotor or a vane of a stator may have a frame formed of metal. The metal frame could be considered an insert. The metal insert of the blade could then have cured rubber bonded thereon. The blade element having the cured rubber bonded thereon could then be placed in a mold. Strips of uncured rubber may then be positioned on the blade element along with one or more ceramic cover members at locations that correspond with determined high wear zone locations for the rotor or stator that is to include the blade or vane. Heat and pressure may then be applied to the blade element to bond the one or more cover members and uncured rubber to the blade element. Multiple blades may be formed using the same process and subsequently bolted to another metal structure for forming a rotor or stator. Thereafter, the formed structure could be positioned in a mold or other mechanism and any uncovered portions of metal from the formed structure of the rotor or stator may have strips of uncured rubber material positioned over the exposed metal portions of the structure. If desired, one or more cover members may also be positioned over those portions for attachment to the structure. Heat and pressure may then be applied to bond the rubber and any cover members to the structure. The formed structure may subsequently be placed into an oven, autoclave, or other device for heating the structure at a curing temperature for a curing time period to cure the formed structure to ensure that the rubber material has a desired bonding strength to metal frame elements of the structure.

Each of the cover members 15 are preferably composed of a ceramic material that is harder and more durable than the polymeric or elastomeric material that coats or covers the component. In some embodiments, it is contemplated that the cover member 15 may be composed of a particularly hard metal, composite material, or other type of material instead of a ceramic material. It should be understood that cover members 15 may be attached to different components, such as a stator, a rotor, a hood, and a draft tube collar so that each of these components may be fabricated for installation in the same flotation machine. In yet other embodiments, the cover members 15 may be considered reinforcing members that are attached within an exterior of a formed component for providing improved wear performance of the component at certain high wear zones such that polymeric or elastomeric material that may initially cover the harder cover member elements wear away to expose the reinforcing cover members after a period of use of the flotation machine component.

It is contemplated that embodiments of the cover members 15 for components of a flotation machine can improve the life of those components and ensure that the flotation machine operates efficiently for a longer period of time as compared to conventional designs. The improved life of a rotor and stator, for example, can reduce costs associated with downtime, maintenance of such parts, and replacement of such parts and can also improve the performance of the flotation machine throughout the life of those parts as compared to conventional designs.

It should be understood that different variations to the above mentioned embodiments of the flotation machine, stator, rotor, hood and draft tube, may be made to meet different design objectives. For example, the blades of the rotor may be arranged in any of a number of ways, have any number of blades, and have any of a number of different shapes to meet a particular set of design criteria. As another example, the stator and hood may be configured to have any of a number of different shapes and configurations that define a particular set of openings to facilitate slurry and bubbles being distributed within the tank of a flotation machine to meet a particular set of design criteria. As yet another example, the tank of the flotation machine may have any of a number of shapes or sizes. For instance, the shape and geometry of the tanks of the flotation cells may be any of a number of different shapes and sizes. The type of material to be recovered by a flotation machine may be any of a number of different minerals or metals such as, for example, copper, iron, coal, a base metal, a special metal, other minerals or other types of metal. As yet another example and as those of at least ordinary skill in the art will appreciate, the types of reagents, types of depressants/activators, use of different pH levels, use of different collectors, frothers, or modifiers may be utilized as needed to meet different material recovery objectives, or other design objectives. Of course, yet other modifications to the embodiments discussed above may be made to meet any of a number of design criteria that may be set or requested by a flotation machine operator for recovery of a material from a slurry retained within a tank of a flotation machine as may be appreciated by those of at least ordinary skill in the art. While certain exemplary embodiments of a flotation machine, a stator, a rotor, a hood, and a draft tube and methods of making and using the same have been shown and described above, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

What is claimed is:

1. A flotation machine comprising:

a tank;

a rotor for rotating in the tank to facilitate froth formation in the tank, the rotor having a plurality of blades,

a stator positioned in the tank adjacent the rotor;

wherein at least one of the rotor, the stator, a draft tube positioned below the rotor and a hood positioned above the rotor is comprised of a polymeric material or an elastomeric material and has at least one cover member attached thereto.

2. The flotation machine of claim 1 wherein the rotor is covered with the polymeric material or the elastomeric material and wherein the at least one cover member is comprised of a plurality of cover members, a respective one of the cover members being attached to a respective one of the blades of the rotors such that the polymeric or elastomeric material is between the cover member and the blade to which that cover member is attached.

3. The flotation machine of claim 1 wherein the stator is also covered with the polymeric material or the elastomeric material and the at least one cover member is comprised of a plurality of cover members; and wherein each vane of the stator is attached to at least one respective cover member such that the polymeric or elastomeric material covering that vane is between an insert of the vane and the cover member.

4. The flotation machine of claim 1 wherein the stator is sized and configured as a disperser having a plurality of holes that is also covered with the polymeric material or the elastomeric material, and wherein the at least one cover member is comprised of a plurality of cover members; and

wherein the cover members are attached to the disperser adjacent the holes of the disperser to cover portions of the disperser that define at least some of the holes of the disperser

5. The flotation machine of claim 1 wherein a collar of the draft tube is covered with the polymeric material or the elastomeric material and has at least one cover member attached thereto such that each cover member covers the polymeric or elastomeric material at a location at which the cover member is attached, each cover member being comprised of a ceramic material that is harder than the polymeric or elastomeric material; and

wherein the draft tube has an inlet for receiving slurry and an outlet for outputting slurry adjacent the rotor.

6. The flotation machine of claim 1 wherein the hood is positioned in the tank above the rotor and has a plurality of holes and is comprised of the polymeric material or the elastomeric material and a plurality of the cover members are attached to the hood adjacent the holes to cover portions of the hood that define at least some of the holes of the hood, each of the cover members being comprised of a ceramic material that is harder than the polymeric material or the elastomeric material.

7. The flotation machine of claim 1 wherein:

the rotor is covered with the polymeric material or the elastomeric material and wherein the at least one cover member is comprised of a plurality of cover members, at least one of the cover members attached to a respective one of the blades of the rotor such that the polymeric or elastomeric material is between the cover member and the blade to which that cover member is attached; and

wherein the stator is also covered with the polymeric material or the elastomeric material and wherein each vane of the stator is attached to at least one respective cover member such that the cover member covers a portion of the polymeric or elastomeric material during use of the flotation machine and is comprised of a ceramic material that is harder than the polymeric or elastomeric material.

8. The flotation machine of claim 7 wherein a collar of the draft tube is comprised of the polymeric material or the elastomeric material and has at least one cover member attached thereto such that each cover member covers a portion of the polymeric or elastomeric material of the collar to which that cover member is attached.

9. The flotation machine of claim 8 wherein the hood is positioned above the rotor and has a plurality of holes and is comprised of the polymeric material or the elastomeric material and a plurality of cover members are attached to the hood adjacent the holes to cover portions of the hood that define at least some of the holes of the hood.

10. The flotation machine of claim 1 wherein each cover member is composed of a ceramic material, siliconized silicon carbide, zirconia toughened aluminum, silicon nitride, zirconia, or alumina oxide.

11. The flotation machine of claim 1 wherein each cover member is comprised of a material that is harder than the polymeric material or elastomeric material.

12. A method of making a component of a flotation machine comprising:

determining at least one location of wear for the component that is at a location at which the wear for the component is greater as compared to other portions of the component when the component is in use during operation of the flotation machine;

placing at least one cover member in a mold that is at a position that corresponds to the determined at least one location of the component at which the wear for the component is greater as compared to other portions of the component when the component is in use during operation of the flotation machine; and

feeding polymeric material or elastomeric material into the mold for forming the component and for bonding the at least one cover member to the formed component.

13. The method of claim 12 wherein the component is one of a rotor, a stator, a disperser, a hood, and a draft tube.

14. The method of claim 12 wherein each cover member is composed of a ceramic material, zirconia toughened alumina, zirconia, silicon nitride, siliconized silicon carbide, or alumina oxide.

15. The method of claim 12 wherein each cover member is comprised of a material that is harder than the polymeric material or elastomeric material.

16. The method of claim 12 further comprising curing the component after the polymeric material or elastomeric material is fed into the mold.

17. The method of claim 12 further comprising:

positioning an insert into the mold; and

installing the component in the flotation machine; and

wherein each cover member is positioned adjacent the insert prior to the polymeric material or elastomeric material being fed into the mold and wherein the insert, the polymeric material or elastomeric material, and each cover member are heated to a pre-specified temperature for a predetermined amount of time for curing prior to the installing of the component in the flotation machine.

18. The method of claim 12 wherein the at least one cover member is comprised of a plurality of sleeves or is comprised of a plurality of annular cover members.

19. The method of claim 12 further comprising:

prior to the placing of each cover member in the mold that is at the position that corresponds to a respective determined location of the component at which the wear for the component is greater as compared to other portions of the component when the component is in use during operation of the flotation machine, the method also includes at least the step of: cold bonding rubber material to a metal insert to at least partially cover the metal insert.

20. The method of claim 12 wherein feeding the polymeric material or the elastomeric material into the mold to form the component and to bond the at least one cover member to the formed component comprises:

positioning strips of uncured rubber material adjacent the at least one cover member in the mold;

and wherein the method further comprises:

applying pressure and heat to the mold to form the component and to bond the at least one cover member to the formed component.