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GB2245504A - Apparatus for separating particulate material from a liquid - Google Patents

Apparatus for separating particulate material from a liquid Download PDF

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Publication number
GB2245504A
GB2245504A GB9114173A GB9114173A GB2245504A GB 2245504 A GB2245504 A GB 2245504A GB 9114173 A GB9114173 A GB 9114173A GB 9114173 A GB9114173 A GB 9114173A GB 2245504 A GB2245504 A GB 2245504A
Authority
GB
United Kingdom
Prior art keywords
screen
liquid
outlet
particulate material
conduit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9114173A
Other versions
GB9114173D0 (en
GB2245504B (en
Inventor
William Baguley
Timothy John Clamp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of GB9114173D0 publication Critical patent/GB9114173D0/en
Publication of GB2245504A publication Critical patent/GB2245504A/en
Application granted granted Critical
Publication of GB2245504B publication Critical patent/GB2245504B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D35/00Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
    • B01D35/26Filters with built-in pumps filters provided with a pump mounted in or on the casing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D29/00Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/11Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
    • B01D29/114Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements arranged for inward flow filtration
    • B01D29/115Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements arranged for inward flow filtration open-ended, the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D29/00Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/88Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices
    • B01D29/885Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices with internal recirculation through the filtering element
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D29/00Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/88Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices
    • B01D29/90Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for feeding
    • B01D29/902Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for feeding containing fixed liquid displacement elements or cores
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D29/00Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/88Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices
    • B01D29/90Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for feeding
    • B01D29/904Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for feeding directing the mixture to be filtered on the filtering element in a manner to clean the filter continuously
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D29/00Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/88Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices
    • B01D29/94Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for discharging the filter cake, e.g. chutes
    • B01D29/945Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for discharging the filter cake, e.g. chutes for continuously discharging concentrated liquid
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2201/00Details relating to filtering apparatus
    • B01D2201/02Filtering elements having a conical form

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)

Abstract

Particulate material, such as carbon or resin granules, are separated from a liquid, such as a slurry of ore from which the granules have adsorbed metal values, by pumping the mixture 20 up a pipe 12 and on to a frusto-conical screen 30. The liquid then passes through the screen to a collector 32, 34, and the granules flow down the screen, either back into tank 10 or into a second collector for recycling (Fig. 2). The pumping is effected by a rotary impeller 22 or by an air lift means 42, 44. Vanes 28 inhibit or allow limited rotation of the rising mixture, and baffle 40 directs it down on to the screen. The pipe 12 may have a wider portion at the top to reduce the flow velocity (Fig. 3). <IMAGE>

Description

"APPARATUS FOR SEPARATING PARTICULATE FROM A LIQUIDS This invention relates to apparatus for separating particulate material from a liquid, such as carbon particles in a slurry.
Carbon-in-pulp and resin-in-pulp processes are commonly used to recover metal values (particularly gold) from a slurry of mined ore. The slurry is circulated through tanks containing carbon or resin particles, and the metal values are adsorbed onto the carbon granules. A screening process of one kind or another is used to separate the metal-laden carbon or resin particles from the slurry, which is usually passed through several tanks in order to extract as much metal as possible.
The efficiency with which carbon or resin particles can be separated from the slurry is crucial to the efficiency of the metal recovery process. It is also desirable to reduce attrition of the carbon or resin particles, which can occur particularly in apparatus which forces the slurry through a screen under pressure.
According to the invention apparatus for separating particulate material from a liquid comprises: a vessel for liquid containing particulate material; a conduit in the vessel with an inlet located to be below the surface of liquid in the vessel and an outlet located to be above the surface; impeller means for pumping liquid and particulate material in the vessel through the conduit and out of the outlet; an inclined screen adjacent to the outlet of the conduit; and a launder below the screen, so that when liquid and particulate material are pumped through the conduit and out of thc outlet, the liquid passes through the screen into the launder, while the particulate material is retained by the screen.
Preferably, the screen surrounds the outlet.
The screen may be frusto-conical and may be concentric with the outlet of the conduit.
The screen may be arranged to allow the retained particulate material to gravitate back into the vessel.
Alternatively, a second launder may be provided for eollection of the retained particulate material.
Preferably, a deflector plate is disposed above the outlet of the conduit to force liquid and particulate material leaving the outlet downwardly over the screen.
The impeller means may comprise an axial flow impeller in the conduit.
Alternatively, the impeller means may comprise an airlift below the inlet of the conduit.
For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic sectional side view of a first embodiment of apparatus according to the invention; Figure 2 is a schematic sectional side view of a second embodiment of the apparatus; and Figure 3 is a schematic sectional side view of a third embodiment of the apparatus In Figure I, a first embodiment of the apparatus of the invention is seen to comprise a la,e tank 10 in which is located an upright conduit in the form of an open ended central pipe 12. The lower end 14 of the pipe serves as an inlet, and is spaced above the bottom 16 of the tank 10.The upper end 18 of the pipe is arranged to extend above the level of liquid 20 in the tank The liquid 20 is typically a slurry of mined ore.
Within the pipe 12 is an axial flow impeller 22 which is connected to an electric motor 24 via a shaft 26. The pipe 12 is fitted with guide vanes 28 above the impeller 22, which control swirling of liquid in the pipe above the impeller. The vanes can be angled to substantially prevent swirling of liquid moving up the pipe, or can be angled to allow a desired degree of swirl. The vanes also prevent undesired waves in the liquid leaving the pipe, and prevent vortexing and cavitation.
The top end 18 of the pipe serves as an outlet, around which is disposed a frusto-conical screen 30. The screen 30 surrounds the mouth of the pipe, and slopes downwardly away from the mouth of the pipe at an angle of #crpproximately 450 The screen 30 is typically constructed from stainlesii steel wire mesh or wedge wire, but can also be constructed from other screen materials such as woven polyester cloth. The screen has apertures which are sized to prevent particles of carbon or resin (or other particulate materials) from passing through the screen, but to allow liquid (or slurry, as in the present example) to pass through.In the case of carbon granules used in a carbon#in-pulp process, the granules are typically 1 to 3 mm in size, so that a screen with an aperture size of 600 to 850 microns is suitable. in the case of resin beads having a size of about 600 to 800 microns, an aperture size of 500 microns is suitable. Below the screen 30 is arranged a helical launder 32, which terminates in a liquid outlet pipe 34. The outer edge of the screen 30 overhangs the launder 32.
The described apparatus is usually one of several making up a metal recovery installation. The tank 10 is filled with a mixture of slurry and carbon granules or particles. For example, an inlet pipe 36 from an adjacent tank may he the source of slurry. When the motor 24 is operated, the impeller 22 rotates, drawing a mixture of slurry and carbon or resin particles up the tube 12. The mixture exits the outlet 18 of the tube and spills outwardly over the screen 30.
A circular top plate 38 and a frusto-conical deflector plate 40 above the screen 30 control the flow of the slurry and carbon or resin particles over the screen. The deflector plate 40 is tapered so that the gap between the deflector plate and the screen narrows towards their respective outer edges, compensating for the increase in volume between the screen and the detector plate radially outwardly thereof. The deflector plate stops short of the edge of the screen, allowing an operator to monitor the operation of the apparatus.
The cover 38 and the deflector plate 40 prevent splashing and turbulence in the liquid passing over the screen, improving the flow rate of liquid through the screen.
It will be understood that although the described screen 30 is fn#)sto-conicaI and surrounds the outlet of the pipe 12, other screen configurations are possible. For example, a multi-section screen or a flat screen could be used, with the pipe 12 being arranged to discharge over the screen Due to the slope of the screen 30, carbon or resin particles in the liquid gravitate down the screen and fall off its edge back into the tank 10, while the slurry passes through the screen, as shown by the arrows beneath the screen, and is collected in the launder 32. The outlet pipe 34 feeds the slurry to the next tank in the series, or elsewhere as required.Due to the effectiveness of the axial flow impeller in the pipe 12, it is relatively easy to generate a head of, say, 1,5 m above the level of the slurry in the tank 10, which leaves a relatively large degree of freedom in designing the screen 30 and the launder 32. This also allows a number of tanks to be located side by side on the same level in a metal recovery installation, making auxiliary pumps unnecessary for pumping the slurry from tank to tank.
In a prototype installation, a four blade impeller was used, the impeller blades having a tip angle of between 20 and 350 and a root angle of approximately 450 Instead of an impeller, it is possible to use an airlift, as indicated in dotted outline in Figure 1. At the bottom of the tank, a pipe 42 for compressed air is arranged wit a ~6y fa=ing outlet 44 directly below the inlet 14 of the pipe 12. By pumping compressed air into the pipe 42 under sufficient pressure, slurry is entrained with air rushing up the pipe, achieving a similar effect to the impeller 22. However, the use of an airlift may be preferable in certain cases, for example, when using relatively friable resin particles for metal adsorption.
The angle of slope of the screen 30 can be varied, but is preferably in the region of 450 from the vertical. Increasing the steepness of the slope improves the rate of removal of carbon particles from the screen, but reduces the effective aperture area of the screen for the slurry passing through the screen Conversely, a more shallow screen (e.g. sloped at 25 or 300) has a larger effective aperture area, but the carbon particles gravitate more slowly down the screen and back into the tank. Of course, the shallower the slope of the saoet, the smaller the head which the impeller is required to generate.
A variation of the apparatus is shown in Figure 2, in which a second launder 46 is disposed below the periphery of the screen 30, around the launder 16.
Carbon or resin particles are thus collected in the launder 46 instead of returning to the tank 10, for transfer in the opposite direction to the slurry in a countercurrent operation, for example. An auxiliary outlet pipe 48 empties the launder 46. In the embodiment of Figure 2, the apparatus may be arranged so that a proportion of the slurry leaving the outlet of the pipe 12 passes over the screen 30 and into the launder 46, to wash tbe carbon particles away. This avoids dilution of the slurry in a countercurrent operation. Alternatively, water or other liquid from a supply valve 50 can be used to wash the collected particles along the launder 46, and out of the outlet pipe 48, from where they can he collected for elutrification.
In the embodiment of Figure 3, the pipe 12 has an enlarged upper portion 52, so that the outlet of the pipe 12 has approximately twice the area of its inlet.
The effect of this arrangement is that the velocity of the slurry in the pipe decreases as it leaves the pipe, reducing splashing and allowing a more efficient escape of fluid from the top of the pipe. Increasing the diameter of the outlet also increases its circumterencc, which enables the height of the opening 54 between the top plate 38 and the outlet of the pipe to be reduced, for a given outlet area. This allows the length of the shaft 26 of the impeller to be reduced, improving the stability of the unit.
The described embodiments of the invention have various advantages, compared with prior art systems. Firstly, the fact that the screen 30 is situated clear of the slurry in the tank means that it is easily inspected for wear and clogging. The pumping characteristics provided by the pipe 12 and the axial flow impeller 22 are consistent, and are less sensitive to screen condition than similar apparatus in which slurry is pumped through a screen. Compared to such apparatus, the pressure gradient across the screen is relatively low, which result5 in improved efficiency and reduced energy consumption. The screen 30 is also less prone to clogging than forced-flow systems, since carbon or resin particles are less inclined to become lodged in the apertures of the screen as they gravitate down the sides of the screen. In contrast, separator devices which pump liquid through a screen tend to clog the screen relatively quickly, as the irregularly shaped carbon particles lodge in the screen apertures and are held against the screen by the pressure gradient across it

Claims (11)

  1. CLAIMS 1. Apparatus for separating particulate material from a liquid comprising: a vessel for liquid containing particulate material; a conduit in the vessel with an inlet located to be below the surface of liquid in the vessel and an outlet located to be above the surface; impeller means for pumping liquid and particulate material in the vessel through the conduit and out of the outlet; an inclined screen adjacent to ths outlet of the conduit; and a launder below the screen, so that when liquid and particulate material are pumped through the conduit and out of the outlet, the liquid passes through the screen into the launder, while the particulate material is retained by the serceit
  2. 2. Apparatus according to claim 1 wherein the screen surrounds the outlet.
  3. 3. Apparatus according to claim 2 wherein the screen is frusto conical and is concentric with the outlet of the conduit.
  4. 4. Apparatus according to any one of claims 1 to 3 wherein the screen is arranged to allow the retained particulate material to gravitate back into the vessel.
  5. 5. Apparatus according to any one of claims 1 to 3 wherein a second launder is disposed below the screen for collection of the particulate material.
  6. 6. Apparatus according to any one of claims 1 to 5 wherein a deflector plate is disposed above the outlet of the conduit to force liquid and particulate material leaving the outlet downwardly over the screen.
  7. 7. Apparatus according to claim 6 wherein the deflector plate extends adjacent to the screen.
  8. 8. Apparatus according to claim 7 wherein the spacing between the deflector plate and the screen reduces in a direction away from the outlet.
  9. 9. Apparatus according to any one of claims 1 to 8 wherein the impeller means comprises an axial flow impeller in the conduit
  10. 10. Apparatus according to any one of claims 1 to 8 wherein the impeller means comprises an airlift below the inlet of the conduit.
  11. 11. Apparatus for separating particulate material from a liquid substantially as hereinbefore described with reference to, and as shown in, any one of Figures 1 to 3.
GB9114173A 1990-06-27 1991-06-27 Apparatus for separating particulate material from a liquid Expired - Fee Related GB2245504B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ZA905008 1990-06-27

Publications (3)

Publication Number Publication Date
GB9114173D0 GB9114173D0 (en) 1991-08-21
GB2245504A true GB2245504A (en) 1992-01-08
GB2245504B GB2245504B (en) 1994-02-16

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Family Applications (1)

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GB9114173A Expired - Fee Related GB2245504B (en) 1990-06-27 1991-06-27 Apparatus for separating particulate material from a liquid

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AU (1) AU646869B2 (en)
GB (1) GB2245504B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5449454A (en) * 1993-01-13 1995-09-12 Aquaria, Inc. Gas expelling device for a canister type filter
GB2297501B (en) * 1993-10-25 1997-07-16 Hydro Int Plc Separator
GB2343385A (en) * 1998-11-04 2000-05-10 Wedge Wire Screens Ltd Filter apparatus with tapering filter screen walls

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB917248A (en) * 1960-06-23 1963-01-30 Stamicarbon Pumping and screening installation for liquids entraining solid particles
US3880762A (en) * 1973-11-19 1975-04-29 Roger Francis Wise Separator for cuttings
GB2232443A (en) * 1989-06-09 1990-12-12 Hanford Eng Ltd A venturi pump apparatus
GB2235393A (en) * 1989-08-25 1991-03-06 Wu Kie Pyng Waste separator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB917248A (en) * 1960-06-23 1963-01-30 Stamicarbon Pumping and screening installation for liquids entraining solid particles
US3880762A (en) * 1973-11-19 1975-04-29 Roger Francis Wise Separator for cuttings
GB2232443A (en) * 1989-06-09 1990-12-12 Hanford Eng Ltd A venturi pump apparatus
GB2235393A (en) * 1989-08-25 1991-03-06 Wu Kie Pyng Waste separator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5449454A (en) * 1993-01-13 1995-09-12 Aquaria, Inc. Gas expelling device for a canister type filter
GB2297501B (en) * 1993-10-25 1997-07-16 Hydro Int Plc Separator
US5698099A (en) * 1993-10-25 1997-12-16 Hydro International Plc Hydrodynamic separator with an incorporated solids interceptor
GB2343385A (en) * 1998-11-04 2000-05-10 Wedge Wire Screens Ltd Filter apparatus with tapering filter screen walls
GB2343385B (en) * 1998-11-04 2002-10-30 Wedge Wire Screens Ltd Improvements relating to screening apparatus

Also Published As

Publication number Publication date
AU7935291A (en) 1993-03-18
GB9114173D0 (en) 1991-08-21
AU646869B2 (en) 1994-03-10
GB2245504B (en) 1994-02-16

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19960627

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