This subject invention relates to a magnetic fluidic sealing system for a wet drum magnetic separator.
Wet drum magnetic separators are often used in the mining industry for recovering magnetite from iron ore. This is achieved by grinding the iron ore to a fine powder having particles sized typically less than about 70 microns. The fine grinding liberates the magnetite from other elements in the ore. The mixture of the magnetite and other elements is slurried in water and the slurry is fed to a wet magnetic drum separator where the more magnetic particles (e.g., magnetite) are extracted from the slurry leaving the less magnetic particles to be discharged as nonmagnetic tailings.
A typical wet drum magnetic separator includes an array of permanent magnetic elements disposed inside the lower portion of a cylindrical drum. The drum rotates in a tank continuously filled with the slurry-water mixture of magnetic and non-magnetic particles. The array of permanent magnetic elements inside the drum is kept in a fixed position close to the inner surface of the drum while the drum rotates in the tank. The more magnetic particles are extracted from the slurry by adhering to the surface of the drum in the region of the magnetic field created by the array of permanent magnets. The less or non-magnetic particles remain in the slurry. In operation, the feed slurry is fed continuously and the separation takes place typically with no interruption. The slurry depleted of the magnetic particles is directed to one discharge port and the magnetic particles are discharged into another discharge port as they leave the magnetic field of the array of permanent magnets.
The practical design limitations of a typical conventional magnetic drum do not allow the axial length of the array of magnetic elements inside the drum to be as long as the drum itself. The axial length of the drum also cannot be as wide as the tank. This results in spaces, typically about 1-2″, between the end of the array of permanent magnets and the end of the drum and between the end of the drum and the end of the tank. The feed slurry, however, is distributed over the full width of the tank and the surface of the drum. The result is regions between the end of the array of permanent magnets and the wall of the tank where the magnetic field provided by the array of permanent magnets cannot interact with the fluid particles in the mixture. This prevents the magnetic particles in the fluid located in those regions from being extracted from the slurry, a phenomenon known as end losses.
Ballasted flocculation and sedimentation processes and/or surface adsorption processes, such as those disclosed in U.S. Pat. Nos. 4,427,550 and 4,981,583 to Priestley et al. and U.S. Pat. No. 6,099,738 to Wechsler et al., each incorporated by reference herein, utilize a wet drum magnetic separator to recover magnetic ballasts, such as magnetite and similar type ballasts, from the effluent of these processes. End losses from the wet drum magnetic separators in these processes increase the processing costs.
It is therefore an object of this invention to provide a magnetic sealing system for a wet drum magnetic separator.
It is a further object of this invention to provide such a magnetic sealing system for a wet drum magnetic separator which reduces end losses.
It is a further object of this invention to provide such a magnetic sealing system for a wet drum magnetic separator which recovers more magnetic particles.
It is a further object of this invention to provide such a magnetic sealing system for a wet drum magnetic separator which increases yield.
It is a further object of this invention to provide such a magnetic sealing system for a wet drum magnetic separator which improves recovery of magnetic ballasts.
It is a further object of this invention to provide such a magnetic sealing system for a wet drum magnetic separator which reduces processing costs.
This invention results from the realization that a magnetic fluid sealing system for wet drum magnetic separator which reduces end loss and improves recovery of magnetic ballasts is effected, in one embodiment, with an array permanent magnetic elements disposed inside a rotating drum of a wet drum magnetic separator arranged in a fixed position relative to an azimuthal section of the drum for attracting the magnetic particles to the surface of the drum. At least one seal is disposed proximate each axial end of the array and is concentrically shaped and spaced from the surface of the drum and extends to a bottom wall of a tank and each seal establishes a magnetic fluidic seal between the surface of the drum and an inner concentric surface of the seal that maintains the magnetic particles inside the magnetic field of the array of permanent magnet to effectively reduce end losses and enhance recovery of the magnetic particles.
The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives.
This subject invention features a magnetic fluidic sealing system for a wet drum magnetic separator including a tank for receiving a flow of a mixture of magnetic and non magnetic particles, a rotating drum disposed in the tank, an array of permanent magnetic elements disposed inside the drum arranged in a fixed position relative to an azimuthal section of the drum for attracting the magnetic particles to the surface of the drum, and at least one seal disposed proximate each axial end of the array concentrically shaped and spaced from the surface of the drum and extending to a bottom wall of the tank for establishing a magnetic fluidic seal between the surface of the drum and an inner concentric surface of the seal that maintains the magnetic particles inside the magnetic field of the array and reduces end losses of the magnetic particles.
In a preferred embodiment, the at least one seal may include a ferromagnetic material. The ferromagnetic material may include carbon steel. The magnetic particles may include magnetite. At least a portion of the tank may be concentrically shaped. At least one seal may be concentrically shaped on one surface to closely match the shape of the surface of the drum and concentrically shaped on another surface to closely match the shape of concentrically shaped portion of the tank. The system may include a structural support configured to resist magnetic forces between the at least one seal and the array. The structural support may include at least one attachment to the tank. The magnetic fluidic seal may be permeable to the fluid carrying the flow of the mixture of magnetic and non magnetic particles. The fluid may include water. The magnetic fluidic seal may provide uniform fluidic pressure proximate each side of said at least one seal. The drum may rotate concurrent to the flow of the mixture of magnetic and non-magnetic particles. The drum may rotate counter-current flow of the mixture of magnetic and non-magnetic particles. The mixture of magnetic and non magnetic particles may be fed between opposing inner surfaces of the at least one seal.
This invention also features a magnetic fluidic sealing system for a wet drum magnetic separator including a tank for receiving a flow of a mixture of magnetic and non magnetic particles, a rotating drum disposed in the tank, an array of permanent magnetic elements disposed inside the drum arranged in a fixed position relative to an azimuthal section of the drum for attracting the magnetic particles to the surface of the drum, a non-magnetic particle discharge port proximate an azimuthal end of the array and inside a magnetic field of the array for removing non magnetic particles, a magnetic particle discharge port proximate the azimuthal end of the array and outside the magnetic field of the array for removing magnetic particles, and at least one seal disposed proximate each axial end of the array concentrically shaped and spaced from the surface of the drum and extending to a bottom wall of the tank for establishing a magnetic fluidic seal between the surface of the drum and an inner concentric surface of the seal that maintains the magnetic particles inside the magnetic field of the array and reduces end losses of the magnetic particles.
This invention further features a magnetic fluidic sealing system including a wet drum magnetic separator, and at least one seal disposed proximate each axial end of an array of permanent magnets inside a drum of the wet drum magnetic separator, the at least one seal concentrically shaped and spaced from the surface of the drum and extending to a bottom wall of the tank for establishing a magnetic fluidic seal between the surface of the drum and an inner concentric surface of the seal for maintaining the magnetic particles in a flow of a mixture of magnetic and non-magnetic particles inside the magnetic field of the array to reduce end losses of the magnetic particles.
This invention further features a mechanical fluidic sealing system for a wet drum magnetic separator including a tank for receiving a flow of a mixture of magnetic and non magnetic particles, a rotating drum disposed in the tank, an array of permanent magnetic elements disposed inside the drum arranged in a fixed position relative to an azimuthal section of the drum for attracting the magnetic particles to the surface of the drum, and at least one seal disposed proximate each axial end of the array concentrically shaped and spaced from the surface of the drum and extending to a bottom wall of the tank, the at least one seal including a mechanical sealing member for engaging the surface of the drum and establishing a mechanical fluidic seal between the surface of the drum and an inner concentric surface of the seal that maintains the magnetic particles inside the magnetic field of the array and reduces end losses of the magnetic particles.
In one embodiment, the sealing member may include a labyrinth seal, a solid rubber seal, or a flexible rubber seal. The sealing member may include a longitudinal opening for receiving a flow of water and a plurality of openings for establishing a seal between the surface of the drum and the mechanical sealing member to prevent the flow of magnetic and non-magnetic particles between the surface of the drum and the mechanical sealing member. At least a portion of the tank may be concentrically shaped. The at least one seal may be concentrically shaped on one surface to closely match the shape of the surface of the drum and concentrically shaped on another surface to closely match the concentrically shaped portion of the tank. The magnetic particles may include magnetite. The system may further include a structural support configured to resist magnetic forces between the at least one seal and the array. The structural support may include at least one attachment to the tank. The drum may rotate concurrent to the flow of the mixture of magnetic and non-magnetic particles. The drum may rotate counter-current flow of the mixture of magnetic and non-magnetic particles. The mixture of magnetic and non magnetic particles may be fed between opposing inner surfaces of the at least one seal and the sealing member. A source of water may be fed at a sufficient rate on one side of the at least one seal and the sealing member to establish a water seal for maintaining the mixture of magnetic and non-magnetic particles on the other side of the at least one seal and the sealing member and for providing uniform fluidic pressure proximate each side of the at least one seal and the sealing member.
Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:
Aside from the preferred embodiment or embodiments disclosed below, this invention is capable of other embodiments and of being practiced or being carried out in various ways. Thus, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. If only one embodiment is described herein, the claims hereof are not to be limited to that embodiment. Moreover, the claims hereof are not to be read restrictively unless there is clear and convincing evidence manifesting a certain exclusion, restriction, or disclaimer.
Conventional wet drum magnetic separator 10,
In operation, fluid mixture 12,
However, as discussed in the Background section above, the design limitations of conventional magnetic wet drum separator 10,
To overcome the problems associated with end loss, magnetic fluidic sealing system 70,
Wet drum magnetic separator 72 includes array of permanent magnets 86 having a similar design as array of permanent magnets 24,
To overcome the problems associated with end losses in regions 58 and 60,
The result is magnetic fluidic sealing system 70 traps the magnetic particles 130 in mixture 76 in space 120 between seals 110 and 114 and the surface 100 of the drum 78. This effectively reduce end losses of the magnetic particles, e.g., in regions 58 and 60,
In one embodiment, tank 74′,
Although, as discussed above with reference to
In one design, mechanical sealing member 210 may be a labyrinth type seal as shown
In one embodiment, flow of water 230,
Although as discussed above with reference to
Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments. Other embodiments will occur to those skilled in the art and are within the following claims.
In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant can not be expected to describe certain insubstantial substitutes for any claim element amended.
This application claims priority to provisional patent application Ser. No. 60/879,373, filed Jan. 9, 2007, incorporated by reference herein.
Number | Date | Country | |
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60879373 | Jan 2007 | US |