AU2008212035A1

AU2008212035A1 - A Particulate Material Cleaning And Classifying Apparatus

Info

Publication number: AU2008212035A1
Application number: AU2008212035A
Authority: AU
Inventors: Walter Scott
Original assignee: WAVERLEY NOMINEES Pty Ltd
Current assignee: WAVERLEY NOMINEES Pty Ltd
Priority date: 2008-09-05
Filing date: 2008-09-05
Publication date: 2010-03-25
Anticipated expiration: 2028-09-05
Also published as: AU2008212035B2

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Invention Title: A Particulate Material Cleaning And Classifying Apparatus Applicant: Waverley Nominees Pty Ltd The invention is described in the following statement: A PARTICULATE MATERIAL CLEANING AND CLASSIFYING APPARATUS Field of the Invention. The present invention relates to process apparatus for cleaning and 5 classifying particulate material. Background Art. Cleaning particulate material is important in a variety of fields including mining and other industrial uses. Although the discussion in this specification is directed mainly toward the cleaning and classifying of carbon 10 particulate material, it is to be recognized that the methodology and apparatus of the invention may be easily used to clean and classify particulate material of other types. The conventional methodology and apparatus for cleaning and to some degree, classifying carbon particulate material is known in the art as "jigging" and an apparatus called ajig is used. 15 A conventional jig 10 used to treat alluvial carbon particulates or gold is a process apparatus having at least one treatment hutch 1 I with a heavy-duty support tray 12 positioned therein to support a bed of iron stone (ragging) 13 that is held in place on the base by a series of retaining divider walls 14 separated at approximately 1 50mm distances. 20 Alluvial carbon particulate material or gold-bearing material is fed into the feed end 15 of the ragging bed and a discharge outlet 16 is provided for waste, off the opposite end of the bed. A fluidizing means 17 is associated with the hutch 1I and the fluidizing means 17 fluidizes the material on the bed, leaving the ragging bed in place as it is too 25 heavy for fluidization. This precipitates the heavier, smaller alluvial carbon particulates or gold through the ragging bed to be collected through a drain opening 18 in a lower portion of the hutch I1 whilst waste material is washed off the discharge end 16 of the hutch 11. The jig 10 fluidizes the carbon particulate with the addition of hutch 30 liquid and typically, additional cross flow water added to the hutch with the feed of carbon particulate. The fluidizing means typically fluidizes the material in pulses which help keep the waste material traveling continuously over the ragging bed as the feed 3 material enters the hutch with the cross flow water. An example of this conventional system is illustrated in Figure 1. It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part 5 of the common general knowledge in the art in Australia or in any other country. Summary of the Invention. - The present invention is directed to a particulate material cleaning and classifying apparatus, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial 10 choice. With the foregoing in view, the present invention in one form, resides broadly in a particulate material cleaning and classifying apparatus including at least one treatment hutch containing a liquid, each treatment hutch including at least one screen bed support for supporting a bed of particulate material thereon and having a 15 feed end and a discharge end, and fluidisation means associated with the treatment hutch to agitate the material on the screen bed support, the liquid extending at least to the top of the bed of material on the screen, the bed of material levelling itself on the screen and travelling from the feed end to the discharge end. The apparatus of the present invention is directed to providing an 20 alternative to the conventionally used jig apparatus. The apparatus of the present invention may be used in conjunction with any type of particulate material. However, carbon particulate and particularly activated carbon particulate form the basis for describing the application of the invention due to its value, usage in industry and loss rates in processes. 25 The particulate material cleaning and classifying apparatus of the invention may also perform other functions including washing, conditioning of new carbon to "smooth" roughened edges on new carbon, and separation of "undesirable" carbon from that which is still optimum for use. Undesirable carbon includes older or spent carbon and also undersized articles. It is also to be recognized that once carbon 30 has been subjected to regeneration processes, the carbon must be regenerated each time it is used and should therefore be separated from new or un-regenerated carbon.

4 Particulate activated carbon has a specific gravity of 0.495 (which is similar to the specific gravity of flour) or approximately 500 kg per cubic metre and therefore transports easily when mixed with water. These properties also ensure that particulate activated carbon is relatively easily fluidised with low fluidisation 5 velocities. The resulting advantages of the properties of particulate activated carbon mean that the particulate activated carbon self levels on the screen bed support and also travels laterally across the screen bed support of the present invention without excessive use of transport fluid provided that the fluidisation/agitation is 10 effective. The effects of gravity, the flowrate of the water and/or the size of the particulate material may be used to promote the flow of the particulate across the bed. Gravity may be used instead or in combination with cross flow fluid. The apparatus of the present invention will normally include at least one treatment hutch. Each treatment hutch will preferably be hopper-shaped having a 15 substantially rectangular upper portion and a tapered lower portion. Of course, the treatment hutch may be shaped differently. Each treatment hutch will typically contain a fluid, normally water. In order to function, each hutch will typically be filled with water before operation commences. 20 Each hutch will normally have at least one opening or outlet positioned in a lower portion. Each of the openings will typically be provided with a valve which are normally closed but can be opened periodically in order to drain waste products, left partly open or adjusted to allow the egress of a controlled amount of fluid. 25 Each hutch normally has side portions that extend above the screen bed support and the bed of particulate material in order to prevent or minimise overflow or spillage of the material, or the fluid contained in the hutch. Typically, more than one hutch may be provided in series. Preferably, the hutches will be provided in a cascading configuration with the outlet from a first 30 hutch associated with the inlet of a second, adjacent hutch. Normally, adjacent hutches will be located at different levels or heights in order to accomplish the cascading function. There may be a spillway type connection between the outlet of a 5 first hutch and the inlet of an adjacent hutch, and/or at the dischareg outlet of the apparatus. Normally, each hutch will be provided with an open top but of course, a cover may be provided. 5 The fluidisation means that may affect one or all of the series of hutches where configured in that form or alternatively, individual fluidisation means may be provided for each hutch in a series. Preferably, a single fluidisation means is provided for all of the series of hutches in order to avoid cancellation or disruption of the fluidisation forces. 10 The apparatus of the present invention also typically includes a screen bed support for supporting a bed of particulate material thereon, the screen bed support having a feed end and a discharge and. The purpose of the support is to support the particulate material both within the treatment hutch and as the bed of material moves from the feed end to the discharge end. As alluded to above, the bed 15 of particulate material may be a travelling bed. The bed support therefore is typically designed to allow transport of the bed across the hutch. Typically, the bed support will have an upper screen member and a lower screen support base or frame. The upper screen member is normally manufactured of wedge wire and/or will be slotted with the slots extending 20 substantially perpendicularly to the direction of transport of the bed. Where provided, the screen support base or frame will normally be manufactured from a plurality of members in a substantially rectangular shape. The base or frame may be braced in order to retain its shape. The function of the base or frame is typically to prevent or minimise the formation of the screen member. 25 The bed support may be located in the hutch at any location but preferably towards an upper or top level. The bed support may be retained in the hutch by suitable retention means. Any method of retention may be used but cam clamps are preferred. Cam clamps are typically rotatable between an engaged and a free condition. 30 Cross flow fluid will typically be provided in each hutch. Normally the cross flow fluid will be water. Any mechanism can be used in order to induce the cross flow in the hutch such as for example the fluid can enter with the particulate 6 feed or alternatively the fluid can be sprayed over the bed separately and in a direction to induce the cross flow. The cross flow fluid will normally be provided at relatively low flowrate or velocity with the feed of the material designed to transport the particulate material across the screen from inlet to discharge. 5 Any form of fluidisation means can be used to agitate the particulate material on the screen. Typically, the fluidisation means will be one of two main types namely, a diaphragm type fluidisation means or alternatively mechanical fluidisation means. Mechanical fluidisation means may alternatively be provided as agitation means or vibration means. Normally the mechanical fluidisation means may 10 include a cam lobe associated with the hutches to provide the fluidisation. Diaphragm fluidisation preferably operates through the diaphragm applying pressure to the fluid in the hutch to move the fluid. The diaphram may be located in the hutch or in an adjacent vessel. As the fluid used will typically be relatively incompressible, a force applied to the fluid in the adjacent vessel can be 15 communicated through to the fluid in the hutch. According to a particularly preferred embodiment, the fluidisation provided will be pulsed. Both the pulse frequency and/or the length or duration of the pulse may be optimised in order to achieve optimum fluidisation within the type of particulate to be treated or the rate at which the particulate is to be treated. 20 The outlet for any one or more of the hutches may be provided with a particulate splitter in order to divide the particulate material exiting that hutch. According to a preferred embodiment, an upper and lower splitter tray may be provided. Preferably, a spray nozzle is located adjacent to the outlet. In use, the heavier/older/smaller/more clogged carbon particulate will typically exit through the 25 lower tray due to the effects of gravity and the newer/lighter carbon particulate will exit through the upper tray, assisted by the fluid exiting the spray nozzle. The particulate splitter may be provided as a pair of separate trays or integrated into a single unit. In operation, the waste from the particulate will typically settle to a 30 lower portion of the hutch for removal whilst the particulate material will be transport laterally across the support bed and out of the discharge of the apparatus.

7 The apparatus of the present invention preferably operates on a continuous basis. On this basis, the apparatus is ideally suited for inclusion into a continuous process such as for example, gold recovery/separation, with spent particulate regenerated or cleaned using the apparatus and then returned to a process 5 step where cleaned particulate is used on a rotating basis. Brief Description of the Drawings. Various embodiments of the invention will be described with reference to the following drawings, in which: Figure 1 is a sectional schematic view of a conventional jig apparatus 10 used to clean carbon particulate in the mining industry. Figure 2 is a sectional schematic view of a cleaning and classifying apparatus according to a preferred embodiment of the present invention with a pair of treatment hutches. Figure 3 is a sectional schematic view of a cleaning and classifying 15 apparatus including a splitter on the carbon discharge end. Figure 4 is a sectional schematic view of a treatment hutch with an alternative fluidization means. Figure 5 is a more detailed view of the upper portion of the fluidization means illustrated in Figure 4. 20 Figure 6 is a perspective schematic view of the configuration illustrated in Figure 4. Figure 7 is a sectional schematic view of a device according to an embodiment of the present invention with an alternative liquid addition means. Figure 8 is a sectional schematic view of preferred method of use of an 25 apparatus according to a preferred embodiment, in a Carbon in Pulp method of gold production or retrieval. Figure 9 is a schematic view of a further possible use of an apparatus according to the present invention. Figure 10 is a sectional side view of a continuous gold stripping 30 process for Carbon in Pulp gold mining including a pair of apparatus according to the present invention. Detailed Description of the Preferred Embodiment.

8 According to the preferred embodiment of the invention, a particulate material cleaning and classifying apparatus 20 is provided. The cleaning and classifying apparatus of the preferred embodiments illustrated in Figures 2 and 3 in particular, is used to treat carbon particulate 22 and 5 includes one or more treatment hutches 21 containing a liquid usually water or a mixture of water and leachate from the carbon. Each treatment hutch 21 includes a screen bed support 23 for supporting a bed 24 of particulate carbon thereon and having a feed 25 and a discharge 26. Each treatment hutch 21 is associated with a fluidisation means 27 to agitate the material on the screen bed support 23. 10 In use, the liquid in the treatment hutch will be to a level at least to the top of the bed 24 of material on the screen 23. Due to fluidisation of the bed 24, the material levels itself on the screen 23 and with some assistance from cross flow fluid, travels from the feed 25 to the discharge 26. Particulate activated carbon has a specific gravity of 0.495 (which is 15 similar to the specific gravity of flour) or approximately 500 kg per cubic metre and therefore transports easily when mixed with water. These properties also ensure that particulate activated carbon is relatively easily fluidised at low fluidisation velocities. Each treatment hutch 21 of the illustrated embodiments is hopper shaped having a substantially rectangular upper portion and a tapered lower portion. 20 In order to function, each hutch will normally be filled with water before operation commences. Each hutch 21 has a drain opening 28 positioned in a lower portion provided with a valve which is normally closed but can be opened periodically in order to drain waste products, left partly open or adjusted to allow the egress of a 25 controlled amount of fluid. An inspection hatch 34 is also provided in a sidewall of each hutch 21. Each hutch normally has side walls 29 that extend above the screen bed support 23 and the bed 24 of material in order to prevent or minimise overflow or spillage of the material, or the fluid contained in the hutch 21. 30 According to the preferred embodiment as illustrated in Figures 2 and 3, a pair of treatment hutches 21 will normally be provided in series in a single process apparatus. The two hutches 21 are provided in a cascading configuration with 9 the discharge 26 from a first hutch (leftmost hutch) being the inlet 25 of the adjacent hutch (right hutch). There is a spillway, overflow or weir 30 discharge connection between the first hutch and the adjacent hutch, and at the discharge 26 of the apparatus 10. 5 The fluidisation means 27 of the preferred embodiment illustrated in Figures 2 and 3 fluidises both of the hutches 21. This will preferably avoid cancellation or disruption of the fluidisation forces if separate fluidisation means were provided for each of the two hutches. The purpose of the screen bed support 23 is to support the travelling 10 bed 24 of material within the treatment hutch 21 as it moves from the feed 25 to the discharge 26. The bed support 23 therefore is designed to allow transport of the bed across the hutch. According to a preferred form, the bed support 23 has an upper screen member and a lower screen support base or frame. The upper screen member 15 is normally manufactured of wedge wire and/or will be slotted with the slots extending substantially perpendicularly to the direction of transport of the bed. Where provided, the screen support base or frame will normally be manufactured from a plurality of members in a substantially rectangular shape. The base or frame may be braced in order to retain its shape. The function of the base or frame is 20 typically to prevent or minimise the formation of the screen member. The bed support 23 may be located in the hutch 21 at any location but normally towards an upper or top level as illustrated in Figures 2 and 3. The bed support may be retained in the hutch by suitable retention means. Any method of retention may be used but cam clamps rotatable between an engaged and a free 25 condition, are preferred. Cross flow fluid, normally water, may be provided in each hutch 21. Any mechanism can be used in order to induce the cross flow in the hutch 21 such as for example the fluid can enter with the particulate feed or alternatively the fluid can be sprayed over the bed separately by a spray nozzle 35 and in a direction to induce 30 the cross flow, as is illustrated in Figure 7. The cross flow fluid will normally be provided at relatively low flowrate or velocity with the feed of the material designed to transport the particulate material across the screen 23 from inlet to discharge.

10 Any form of fluidisation means can be used to agitate the particulate material on the screen. Typically, the fluidisation means will be one of two main types namely, a diaphragm type fluidisation means, one form of which is illustrated generally in Figures 4 to 6 or alternatively mechanical fluidisation means, one form of 5 which is illustrated in Figures 2 and 3. The mechanical fluidisation means illustrated in Figures 2 and 3 includes a drive means which rotates a cam lobe associated with the hutches to provide the fluidisation. A connection rod 33 connects the cam lobe to each of the hutches 21 and typically there will be a connection rod on each side of each hutch. 10 Diaphragm fluidisation, forms of which are illustrated in Figures 4 to 6, operates through a plunger 36 applying pressure to the fluid in the hutch 21 to move the fluid. The plunger 36 may be located in the hutch, as illustrated in Figure 6 for example, or in an adjacent vessel or hutch with an opening 37 for communication of the fluid, as illustrated in Figure 4. As the fluid used will typically be relatively 15 incompressible, a force applied to the fluid in the adjacent vessel is communicated through to the fluid in the hutch. Where provided in the hutch itself, the plunger may be surrounded by a diaphragm 38 and the plunger will normally have an air bleed or valve 39 to allow trapped air to escape. 20 According to preferred embodiments, the fluidisation provided will be pulsed. Both the pulse frequency and/or the length or duration of the pulse may be optimised in order to achieve optimum fluidisation within the type of particulate to be treated or the rate at which the particulate is to be treated. Again, the pulsations can be provided according to any method but a 25 system as illustrated in Figure 5 may be used. The pulsation system there illustrated has a cam 32 connected to a drive rod 40 which is in turn connected to the plunger. Rotation of the cam 32 will lift and lower the drive rod 40 and plunger 36. As illustrated in Figure 3, the discharge 26 for any one or more of the hutches may be provided with a particulate splitter 41 in order to divide the 30 particulate material exiting that hutch. According to the illustrated embodiment, an upper and lower splitter tray are provided. Preferably, a spray nozzle 42 is located adjacent to the splitter 41. In use, the heavier/older/smaller/more clogged carbon 11 particulate will typically exit through the lower tray due to the effects of gravity and the newer/lighter carbon particulate will exit through the upper tray, assisted by the fluid exiting the spray nozzle 42. In operation, the waste from the particulate will typically settle to a 5 lower portion of the hutch 21 for removal whilst the particulate material will be transport laterally across the support bed 23 and out of the discharge 26 of the apparatus. The apparatus of the present invention preferably operates on a continuous basis. On this basis, the apparatus is ideally suited for inclusion into a 10 continuous process such as for example, gold recovery/separation, with spent particulate regenerated or cleaned using the apparatus and then returned to a process step where cleaned particulate is used on a rotating basis. The preferred embodiment as described particularly relates to the recovery of gold in the Carbon In Pulp (CIP) method of gold production. According 15 to that particular method of gold production, cyanide is used in a continuous production plant to dissolve gold from finely ground ore or pulp and particulate carbon is used to collect the gold solution from the pulp. The pulp is pumped at approximately 40% to 50% by weight in water into the first of a series of tanks (tank 1) and overflows through the remainder of the 20 series of tanks to waste approximately 24 hours later. Each tank typically has one or more agitators to keep the pulp in suspension within the tank. Particulate carbon is typically present in all of the tanks and is collected from each tank in reverse. That is, carbon from the last tank is collected and fed to the second last tank, and then to the third last tank and so on until it reaches 25 tank 1. At tank 1, the carbon is removed, typically loaded with gold and then proceeds to a stripping column to remove the gold from the carbon. A schematic illustration of this process flow appears in Figure 8 with a schematic of a stripping column illustrated in Figure 10. The stripping column is adapted to remove the gold from the 30 particulate carbon, and the carbon is then sent to a regeneration plant where it is heated until red hot then rapidly cooled or quenched in water, prior to recycle into the last tank in the process.

12 According to the conventional process, a 91% recovery of gold is considered excellent and in theory, at least 7% of the particulate carbon cannot be used each time it is recycled through the system. As illustrated in Figures 9 and 10, the apparatus 20 of the present 5 invention is particularly well-suited to inclusion in a continuous process. Normally, the apparatus will be located above and/or before particular process vessels. For example, as illustrated in Figure 9, the apparatus of the present invention is located prior to a pulp tank 43. According to the schematic process illustrated in Figure 10, a pair of 10 cleaning and classifying apparatus 20 are provided. The first of the apparatus is provided before the stripping column 44 to clean and classify a fresh carbon prior to contact with the cyanide and gold solution and a second apparatus 20 is provided after the stripping column 44. There are a number of different ways in which the apparatus of the 15 present invention can be incorporated into a method for gold recovery. For example, undersized carbon may be removed from any one of the pulp tanks, either before or after absorption of the gold onto the carbon. This carbon would normally flow through the system and be lost to waste. If the carbon had absorbed gold, the gold would be lost as well. 20 The apparatus of the present invention may be used to replace a conventional vibrating screen to remove not only fine pulp from the carbon (cleaning) but also to eliminate course ground pulp. When this course ground pulp in carbon becomes excessive, it is common to have the carbon dumped or stockpiled. If the apparatus of the present invention is used, the carbon can be cleaned and then reused. 25 Any fine loaded carbon that has been screened with a conventional vibrating screen prior to a stripping column can be removed from the fine pulp without loss of the fine carbon. During shutdown of a CIP gold mining plant, the pulp tanks are normally cleaned out including any buildup of material therein. The first tank in the 30 series normally has the largest buildup of material and normally, loaded carbon is included in this buildup. This material is typically stockpiled on site. Use of the present invention means that this carbon can now be cleaned and reused. Typically, 13 according to this use, a deeper bed may be required which may require higher sides and overflow weir at the discharge of the treatment hutch. To avoid removal of course material that will typically build up on the screen bed support, a bleeder attachment may be fitted onto each treatment hutch to drain off this waste as required. 5 Further, as carbon wears out or becomes spent through the system, new carbon is typically continuously added and is mixed with the older or partly worn carbon. According to the present invention, carbon can be removed from the stripping column and then separated into older and fresher carbon over the discharge end of the apparatus. The preferred pulsation action will typically classify the 10 material and the splitter can be used for this purpose. The newer carbon may be reused rather than being regenerated as once the carbon has been regenerated it must be regenerated prior to each use. The newer or larger carbon can be recycled directly back into the process to eliminate unnecessary regeneration and reduce carbon lost through cracking. 15 Further, the newer carbon has roughened edges and also contains dust particles. Use of the apparatus of the present invention results in the water/carbon mix travelling through the system at a faster pulse rate that typically will agitate the carbon to smooth roughened edges that would normally break off and be lost to waste during a conventional process. 20 Still further, the apparatus of the present invention can be used to clean and classify carbon which has been regenerated. Regenerated carbon is typically rapidly cooled which may cause cracking and the apparatus of the present invention will typically agitate the carbon to remove cracked or broken carbon caused by this rapid cooling. 25 The apparatus of the present invention can also be used in other industries such as the activated carbon manufacturing industry and large-scale water treatment plants to regenerate and reactivate exhausted carbon by cleaning it for reuse. According to the preferred embodiment, every square foot of the 30 jigging surface of the present invention, approximately 8'x4', produces approximately 32 cubic yards per hour. Screen sizes can be 8'x4' producing about 16 cubic yards per hour or 6'x3' producing about 8 cubic yards per hour. In the illustrated 14 embodiment, with two 8'x4' hutches producing about 16 cubic yards per hour each, throughput is approximately 32 cubic yards per hour which equates to approximately 4-5 tonnes per hour. In the present specification and claims (if any), the word "comprising" 5 and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present 10 invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations. In compliance with the statute, the invention has been described in 15 language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by 20 those skilled in the art.

Claims

1. A particulate material cleaning and classifying apparatus including at least one treatment hutch containing a liquid, each treatment hutch including at least one screen bed support for supporting a bed of particulate material thereon and 5 having a feed end and a discharge end, and fluidisation means associated with the treatment hutch to agitate the material on the screen bed support, the liquid extending at least to the top of the bed of material on the screen, the bed of material levelling itself on the screen and travelling from the feed end to the discharge end. 10

2. A particulate material cleaning and classifying apparatus as claimed in claim I wherein the effects of gravity are used to promote the flow of the particulate material.

3. A particulate material cleaning and classifying apparatus as claimed in claim 1 or claim 2 wherein each treatment hutch is hopper-shaped having a substantially 15 rectangular upper portion and a tapered lower portion.

4. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein each treatment hutch contains a fluid to a level to or exceeding the height of the bed.

5. A particulate material cleaning and classifying apparatus as claimed in any one of 20 the preceding claims wherein each hutch has at least one outlet positioned in a lower portion to drain waste from the hutch.

6. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein each hutch has sidewall portions that extend above the screen bed support and the bed of particulate material in order to minimise 25 lateral overflow or spillage of the material, or the fluid contained in the hutch.

7. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein more than one hutch is provided in series, in a cascading configuration with the outlet from a first hutch associated with the inlet of a second, adjacent hutch. 30

8. A particulate material cleaning and classifying apparatus as claimed in claim 7 wherein a pair of hutches are provided in a single apparatus. 16

9. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein the fluidisation means effects all of the hutches.

10. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein the bed support has an upper screen member and a 5 lower screen support frame.

11. A particulate material cleaning and classifying apparatus as claimed in claim 10 wherein the upper screen member has openings extending substantially perpendicularly to the direction of transport of the bed to allow waste therethrough. 10

12. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein the screen bed support is releasably located in an upper portion of the hutch using cam clamps rotatable between an engaged and a free condition.

13. A particulate material cleaning and classifying apparatus as claimed in any one of 15 the preceding claims wherein cross flow fluid is provided in each hutch to induce the cross flow of the fluid and bed in the hutch.

14. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein the fluidisation means is a diaphragm type fluidisation means 20

15. A particulate material cleaning and classifying apparatus as claimed in any one of claims 1 to 13 wherein the fluidisation means is a mechanical fluidisation means.

16. A particulate material cleaning and classifying apparatus as claimed in claim 14 wherein the diaphragm is located in the hutch.

17. A particulate material cleaning and classifying apparatus as claimed in any one of 25 the preceding claims wherein the fluidisation provided is pulsed.

18. A particulate material cleaning and classifying apparatus as claimed in claim 17 wherein both the pulse frequency and the duration of the pulse is optimised in order to achieve optimum fluidisation dependant upon the type of particulate to be treated. 30

19. A particulate material cleaning and classifying apparatus as claimed in claim 17 or claim 18 wherein the pulse frequency and the duration of the pulse is 17 optimised in order to achieve optimum fluidisation dependant upon the rate at which the particulate is to be treated.

20. A particulate material cleaning and classifying apparatus as claimed in any one of the preceding claims wherein the discharge is provided with a particulate splitter 5 in order to divide the particulate material exiting that hutch according to size.

21. A particulate material cleaning and classifying apparatus as claimed in claim 20 wherein a spray nozzle is located adjacent to the particulate splitter to assist with separation.

22. A particulate material cleaning and classifying apparatus as claimed in any one of 10 the preceding claims used to treat carbon and activated carbon particulate.

23. A particulate material cleaning and classifying apparatus substantially as described with reference to any one of Figures 2 to 10.