CN111819003A

CN111819003A - Apparatus and method for recovering particles from a slurry

Info

Publication number: CN111819003A
Application number: CN201980018202.XA
Authority: CN
Inventors: 罗兰·米歇尔·马修·蒂斯
Original assignee: Luo LanMixieerMaxiuDisi
Current assignee: Luo LanMixieerMaxiuDisi
Priority date: 2018-03-14
Filing date: 2019-03-12
Publication date: 2020-10-23
Anticipated expiration: 2039-03-12
Also published as: EP3765199A4; WO2019178620A1; EP3765199A1; AU2019233936A1; RU2020133448A; ZA201901524B; CN111819003B

Abstract

The present invention relates to an apparatus and method for recovering suspended particles from a slurry. The apparatus includes a body, at least one operatively inclined corrugated plate and a collector. The body defines a slurry flow region and has an inlet and an outlet in operatively upper and lower regions of the body, respectively, with the flow region extending between the inlet and outlet. The corrugated plate is contained within the body and includes at least one corrugation forming peaks extending within the flow region. A collector is associated with at least one peak and is positioned on an inlet side of the corrugated sheet, with the mouth of the collector positioned at an edge of the corrugated sheet to allow low density particles in the slurry flow region to rise and be directed along the bottom of the peak toward the mouth of the collector. In an inverted configuration, the apparatus and associated methods can be used to recover particles from a slurry that are more dense than the slurry.

Description

Apparatus and method for recovering particles from a slurry

Technical Field

The present invention relates to an apparatus and method for recovering particles from a slurry. And is particularly useful for recovering suspended particles (e.g., hollow ceramic microspheres) from a slurry (e.g., a water-based slurry) containing the suspended particles. However, in an inverted configuration, the apparatus and method may be used to recover particles from a slurry that are greater than the density of the slurry.

Background

Hollow ceramic microspheres composed of alumina and silica filled with air or inert gas are a by-product of the combustion of coal at temperatures between about 1500 ℃ and 1750 ℃. These hollow ceramic microspheres, called "cenospheres," are present in fly ash from thermal power plants. Their chemical composition and physical properties vary depending on the combustion process and the composition of the coal used. Each such ceramic microsphere typically has a diameter of about 5 to 500 microns and a density of between 0.4 and 0.8g/cm3, which is less than the density of water.

Hollow ceramic microspheres were originally considered an undesirable and intractable waste because once dried, they became a persistent airborne dust. In addition, its low density makes it unsuitable for landfills, where groundwater will flush it to the surface. However, at the time of filing this application, it has become a valuable commodity with a commercial value of about $ 1000 per ton. Depending on their grade, hollow ceramic microspheres have various industrial applications, including use in lightweight insulation products, to name a few; fillers for paints, varnishes and plastics; lightweight aggregate in concrete; and a filler for asphalt rubber. The benefits of using hollow ceramic microspheres as fillers in such applications include weight reduction, reduced viscosity, reduced shrinkage, and improved fire performance.

The main byproducts of coal-fired thermal power plants are slag, bottom ash and fly ash. The heavier slag and bottom ash can be removed at the bottom of the power plant boiler, while the lighter fly ash rises and is typically transported with the flue gas, separated from the flue gas and transported to the ash dam by dry or wet methods.

The wet delivery of the fly ash may form a slurry and drain into the settling tank. Here, most of the ash will settle and the floating hollow ceramic microspheres will rise to the surface. However, the density difference between the hollow ceramic microspheres and water makes the rate of microsphere rise toward the surface of the water extremely slow. Workers need to manually collect the floating hollow ceramic microspheres by skimming them off the water surface. Thus, the process can be quite laborious and time consuming.

In addition, about 80% of the hollow ceramic microspheres contained in the fly ash are destroyed, trapped or contaminated by ash, or are unusable during transportation to the settling pond. Since the formation of these hollow ceramic microspheres is only about 0.2% to 2% of the fly ash from which they are derived, such a high percentage of further loss is not sustainable.

Accordingly, there is room for improvement in this regard, and the invention disclosed herein addresses these and other deficiencies, at least to some extent. Furthermore, the present invention achieves a dual purpose, since the device is reversible to separate particles from the slurry that have a density greater than the density of the slurry.

The foregoing discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in the art at the priority date of the application.

Disclosure of Invention

According to the present invention, there is provided an apparatus comprising:

a body defining a slurry flow region and having an inlet and an outlet at first and second opposed regions of the body, respectively, the slurry flow region extending between the inlet and the outlet;

at least one operatively inclined corrugated plate contained within said body, said corrugated plate comprising at least one corrugation forming a peak or valley extending within the slurry flow region; and

a collector disposed at an inlet side of the corrugated sheet, and:

the collector being associated with at least one peak, the mouth of the collector being positioned at an edge of the corrugated sheet to allow particles of lesser density than the slurry in the slurry flow region to rise and be directed along the underside of the peak towards the mouth of the collector; or

The collector is associated with at least one valley, and the mouth of the collector is positioned at the edge of the corrugated sheet to allow particles of a density greater than the pulp to fall in the pulp flow region and be directed along the upper side of the valley towards the mouth of the collector.

Further characterized by having a plurality of spaced and operatively inclined corrugated plates contained within said body, each corrugated plate including at least one corrugation forming a peak or a valley extending within said slurry flow region; and each corrugated plate has a plurality of corrugations to form a plurality of peaks and a plurality of valleys.

Another feature is that the valleys of the corrugated sheet are arranged such that high density particles contained in the slurry are directed down the operatively top side of the valley.

When the density of the particles to be recovered is lower than the density of the slurry, the opposed first and second regions of the body refer to the operatively upper and lower regions of the body, respectively. Further characterized in that the respective corrugations of adjacent corrugated sheets form groups of peaks; and each group of peaks has a collector associated with it arranged on the inlet side of the corrugated plate, the mouth of each collector resting against the edge of the corrugated plate.

Another feature is that each collector is in fluid communication with a standpipe that extends operatively upwardly from the collector to direct the low density particles from a port of the collector and out of the body through the standpipe. Another feature is that the collector is operably tapered upwardly to intersect the standpipe to assist the low density particles in the slurry to enter and travel along the standpipe.

Alternatively, when the density of the particles to be recovered is greater than the density of the slurry, the opposed first and second regions of the body are referred to as the operatively lower and upper regions, respectively. Further characterized by forming respective corrugations of adjacent corrugated sheets into groups of valleys; and for each group of valleys there is associated with it a collector arranged at the inlet side of the corrugated plate, the mouth of each collector abutting against the edge of the corrugated plate.

Another feature is that each collector is in fluid communication with a dip tube extending operatively downwardly from the collector to direct the high density particles from the mouth of the collector and out of the body through the dip tube. Another feature is that the collector is operably tapered downwardly to intersect the caisson to assist the high density particles in the slurry entering the caisson and traveling along the caisson.

Another feature is that the body defines an intermediate space between its inlet and the corrugated sheet, and the intermediate space contains one or more baffles positioned transversely to the flow area of the slurry.

It is still further characterized by providing said body with an operatively vertical portion and an angled portion downstream of the operatively vertical portion, the inlet being disposed in the operatively vertical portion and the one or more corrugated plates being located in the angled portion; and funnels the second region of the body into the outlet.

Further characterised in that the operative inclination of each corrugated plate is between 60 ° and 80 °, preferably 70 °, to the horizontal plane; and the inclined portion of the main body has substantially the same inclination as the corrugated plate.

Further features provide a slurry comprising a mixture of water, fly ash, and hollow ceramic microspheres; making the low-density particles hollow ceramic microspheres; the hollow ceramic microspheres are hollow microspheres.

The invention extends to a method of extracting low density particles from a slurry, the method comprising:

providing an apparatus as described above;

receiving a slurry containing low density particles into a body through an inlet;

flowing the slurry along a slurry flow region;

causing the low density particles to rise and be directed along the underside of at least one peak formed by at least one inclined corrugated sheet;

the low density particles are passed into the mouth of a collector associated with each peak.

The invention also extends to a method of extracting low density particles from a slurry comprising the steps of:

said slurry flowing into the body through the inlet and flowing through a flow region comprising at least one operatively inclined corrugated sheet comprising at least one corrugation forming a peak extending along said flow region;

causing the low density particles to rise and be directed along the bottom side of at least one peak formed by at least one inclined corrugated sheet;

collecting, in one or more collectors associated with each peak, low-density particles rising along at least one peak formed by at least one inclined corrugated plate; and is

Directing low density particles from the collector through the riser operably upwardly beyond the level of the inlet into the body.

The invention further extends to a method of extracting high density particles from a slurry, the method comprising:

providing an apparatus as described above;

receiving a slurry containing high density particles into a body through an inlet;

flowing the slurry along a slurry flow region;

sinking the high density particles and guiding them along the upper side of at least one valley formed by at least one inclined corrugated plate;

the high density particles are caused to enter the mouth of the collector associated with each valley.

The invention further extends to a method of recovering high density particles from a slurry comprising the steps of:

flowing a slurry into a body through an inlet and through a flow region comprising at least one operatively inclined corrugated sheet comprising at least one corrugation forming a valley extending along the flow region;

sinking said high density particles and being directed along an upper side of at least one valley formed by at least one inclined corrugated sheet;

collecting high density particles sinking from at least one valley formed by at least one inclined corrugated plate in one or more collectors associated with each valley; and is

The high density particles from the collector are directed to operatively flow downwardly where they are drawn from the body through the dip tube, above the height of the body inlet.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings.

Brief description of the drawings

In the figure:

FIG. 1 is a perspective view of an apparatus for separating low density particles from a slurry according to the present invention;

FIG. 2 is a cross section of a corrugated sheet contained within the body of the device shown in FIG. 1;

FIG. 3 is a cross-sectional view of two adjacent corrugated sheets;

FIG. 4 is a perspective view of a corrugated sheet and a collector associated with the peaks of the corrugated sheet;

FIG. 5 is a perspective view of an alternative embodiment of a corrugated sheet and a collector associated with the peaks of the corrugated sheet;

FIG. 6 shows a flow diagram of a method of separating low density particles from a slurry using the apparatus of FIG. 1;

FIG. 7 is a perspective view of an apparatus for separating high density particles from a slurry according to a second embodiment of the present invention; and

fig. 8 is a cross section of two adjacent corrugated sheets of the device of fig. 7.

Detailed description with reference to the drawings

An apparatus for separating low density particles from a slurry is provided. It finds particular application in the removal of hollow ceramic microspheres from water-based slurries that are part of the wet separation process of fly ash from coal-fired thermal power plants.

In one exemplary embodiment, the hollow ceramic microspheres may be hollow microspheres.

The apparatus has a body defining a region along which slurry can flow in use. The body has an inlet at an operatively upper region thereof for receiving the slurry, and an outlet through which the remaining slurry (i.e. a portion of the slurry remaining after the low density particles have been at least partially extracted therefrom) can exit the body.

The body comprises at least one operatively inclined corrugated plate having at least one corrugation forming a peak. For efficiency reasons, the body may typically comprise a plurality of corrugated sheets, each corrugated sheet having a plurality of corrugations, thereby forming a plurality of peaks and valleys. Adjacent corrugated sheets are spaced apart to form a flow region therebetween through which slurry can flow. The direction of the inclined peaks and troughs of the corrugated plates generally extend in the flow path.

The device further comprises one or more collectors, each associated with one of the peaks and arranged at the inlet side of the corrugated plate. The mouth of each collector is positioned at the edge of the corrugated sheet. When a plurality of corrugated sheets is used, the corresponding corrugations on adjacent corrugated sheets may form sets of peaks. Thus, a collector may be associated with each peak, so that a group associated with the mouth of the associated collector may be provided, wherein the group of peaks ends at the inlet side of the corrugated plate.

In use, a slurry comprising low density particles, for example a slurry comprising hollow ceramic microspheres, may enter the body through the inlet and may flow to the outlet. The low density particles may rise and be directed along the bottom of each peak toward the mouth of each collector. Thus, particles traveling along the bottom of a particular set of peaks may enter a common collector.

Since the operation of the apparatus depends on gravity and the relative densities of the slurry components, it will be understood that reference to "vertical" or "horizontal" throughout this specification refers to the orientation of the apparatus in use. Similarly, relative orientations, such as "below" and "above," refer to the device being in a vertical orientation.

Fig. 1 shows an exemplary embodiment of an apparatus (1) for separating low-density particles from a slurry. For illustrative purposes, the apparatus (1) and its operation will be described in one example, wherein the low-density particles are hollow ceramic microspheres contained in a fly ash slurry. However, it will be apparent to those skilled in the art that the apparatus may be used to separate any particles or screen particles having a density lower than the density of the remaining components contained in the slurry.

The device (1) has a body (3), which body (3) has a vertical portion (5) and an inclined portion (7) below the vertical portion. Both the vertical portion (5) and the inclined portion (7) have a substantially rectangular cross-section. An inlet (9) is provided in the vertical portion (5) near the top of the apparatus (1), through which inlet (9) slurry can be received into the body (3). In the lower region of the inclined portion (7), the body defines a funnel (11), the outlet (13) of the body being disposed at the narrow end of the funnel (11). In use, slurry may flow through the body (3) from the inlet towards the outlet within a flow region (12) of the body defined between the inlet and the outlet.

In this embodiment, the inclined portion (7) is at an angle of about 70 ° to the horizontal. Within the inclined portion (7) a plurality of spaced apart and substantially parallel corrugated plates (15) are included, said corrugated plates (15) also being substantially at an angle of 70 ° to the horizontal. Each corrugated plate (15) has a plurality of corrugations and thus defines a plurality of peaks (17) and valleys (19) formed by the corrugations.

As shown more clearly in the transverse cross-sectional view of fig. 2, the respective peaks (17) of adjacent corrugated sheets together form parallel groups of peaks (21). Turning now to fig. 4, at the inlet side edge (23) of the corrugated sheet (15) there is provided a collector (25) at each group of peaks (21), whereby each collector is associated with a peak (17) in the respective group of peaks (21). The mouth (27) of each collector is located against the edge (23) of the plate and is arranged to collect microspheres flowing upwardly from the peak groups (21), as will be described in more detail below.

Each collector (25) is in fluid communication with a riser (29), the riser (29) extending upwardly from the collector for directing microspheres out of a port (27) of the collector (25) and out of the body (3) through the riser (29).

In the intermediate space (31) which is usually located between the inlet (9) and the corrugated plate (15), vertically spaced baffles (33) are arranged so that they are positioned transversely to the flow direction.

Fig. 6 shows a flow diagram of a method (500) for separating low density particles from a slurry using the apparatus (1). As a first step, a fly ash slurry is fed (501) to the body (3) through the inlet (9). The slurry may be gravity fed, pumped into the body or a combination of both. The slurry will enter the intermediate space (31) in the vertical section (5) and flow downwards past the baffle (33). The baffles (33) help to reduce turbulence of the slurry flow, as the result may be more effective when the downward flow through the apparatus is uniform or as close to uniform as possible.

As a second step, the pulp is caused to flow (502) along the pulp flow zone and through the spaces between adjacent corrugated sheets (15). The flow parameters of the slurry through these spaces between adjacent plates, and in particular its flow rate, are configured to allow separation of the hollow ceramic microspheres from the heavier remainder of the slurry, as further described with reference to fig. 6.

Fig. 3 shows a longitudinal section of two adjacent corrugated plates (15). The upper panel is shown cut at one peak (17) while the lower panel is shown cut at one valley (19). Fig. 3 shows a state in which the space (50) between adjacent plates is completely filled with the slurry, which in this exemplary embodiment is water-based. The slurry is a mixture of low density hollow ceramic microspheres (51) and high density ash particles (53) along with other heavier impurities. It will be appreciated that the remainder of the space (50) between adjacent plates is filled with water.

The fact that the density of the hollow ceramic microspheres (51) is lower than that of water will cause the microspheres to rise in the water (503), provided that the flow rate must be slow enough to prevent the microspheres from being carried along. As the hollow ceramic microspheres (51) move upwardly in the spaces (50) between adjacent plates (15), the microspheres will eventually encounter the bottom surface of the upper plate. The hollow ceramic microspheres (51) will be directed along the upwardly sloping edges of the corrugations towards the peaks (17) of the upper plate. Once the microspheres (51) reach the peaks (17) of the upper plate, they will be directed upwards along the peaks of the lower surface of the upper plate.

Conversely, ash particles (53) move downward in the spaces (50) between adjacent plates (15) because the density of the ash particles (53) and other higher density impurities is denser than water. As ash particles (53) move downward, they will eventually encounter the upper surface of the lower plate. The ash particles (53) will be directed along the downwardly sloping edges of the corrugations towards the valleys (19) of the lower plate. Once the ash particles (53) reach the valley (19) of the lower plate, they are directed along the valley of the upper surface of the lower plate towards the hopper (11) and towards the outlet (13).

When the microspheres (51) moving up the peaks reach the inlet side edge (23) of the corrugated sheet (15), they will enter the mouth (27) of the collector (25) associated with the relevant group of peaks (21). The microspheres (51) will continue to rise in the riser (29) and eventually leave the body (3) and will be transported further. The remaining slurry, including the high density ash (53) and other impurities, may be discharged from outlet (13) and transported for further processing.

Figure 4 shows the arrangement of the parallel plates. In fact, the fact that the sheet is corrugated plays a very important role in the collection of microspheres. As the microspheres float up the bottom surface of the sheet, they move toward the peaks of the taller sheet where they collect and travel along these peak ridges to the top of the sheet. Where they float into the inverted collecting channel. These inverted channels cover all points where the microspheres leave the peaks of the sheet. From there they float up through the riser and are collected at the top.

FIG. 5 shows the parallel plate arrangement of FIG. 4, wherein an alternative tapered embodiment of the collector (25) better assists the microspheres (51) to enter up and move along the riser (29). While the conical collectors (25) are illustrated as operably tapering upwardly from each end to intersect the midspan of the respective risers (29) of the collector (25), it should be understood that the risers (29) may be positioned at any location along the length of the collector (25), only requiring the collector (25) to taper appropriately upwardly to intersect the risers.

Similarly, the ash will slide down the sheet and move to the valleys of the sheet and be discharged through a drainage chute to an outlet.

The above-described apparatus (1) and method (500) may solve two problems associated with the separation of hollow ceramic microspheres by flotation according to the prior art. The first problem to be solved is that the microspheres float at a very slow rate. They generally rise in water at a rate of 100mm per minute, depending on the density and size of the particular microspheres. By passing the slurry between closely spaced parallel sheets, which can typically be about 10mm apart, the microspheres need only rise upwardly by about 15mm to reach the bottom surface of the sheet directly above it. Its upward travel path is then defined by the peaks in the corrugations, which, upon reaching the upper edge of the plate, will enter the mouth of the collector and move further upward in the riser.

In contrast, using conventional flotation methods, a very large flotation cell would be required to allow sufficient residence time for the hollow ceramic microspheres to escape to the surface of the slurry. For example, in a conventional flotation cell 5m deep, the microspheres will typically take 30min to reach the surface.

The second problem to be solved is that the apparatus and the method using the same can improve the purity of the extracted microspheres compared to the purity extracted by the conventional method. This increase in purity may be due to the fact that: once the microspheres reach the inverted collector tube or peak, they may no longer be in contact with the ash particles and only the microspheres will rise up towards the riser (with as little impurities as possible). The extraction of the microspheres from the riser will be above the water surface, away from the slurry below.

Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

The device may further be manufactured in a modular structure so as to provide a customized device for varying the flow rate of the slurry and/or hollow particle recovery. The modular structure will be formed by a standard unit which can receive the corrugated sheets removably inside, so that the number of corrugated sheets can be changed as desired. Alternatively, the modular structure will be constructed from a standard unit having a fixed number of corrugated sheets, and the number of standard units making up the apparatus may be varied as required.

Although the present invention has been described above with reference to preferred embodiments, it should be understood that many modifications or variations may be made to the present invention without departing from the spirit or scope of the invention. For example, and where like reference numerals refer to like components, the apparatus (10) may be used in an inverted configuration as shown in fig. 7 to be operable as a clarifier or the like.

Fig. 7 shows an exemplary embodiment of an apparatus (10) for separating high density particles from a slurry. The device (10) has a body (30), the body (30) having a vertical portion (50) and an inclined portion (70) above the vertical portion. The vertical portion (50) and the inclined portion (70) each have a substantially rectangular cross section. An inlet (90) is provided at the vertical portion (50) such that the inlet (90) is near the bottom of the apparatus (10) through which slurry may be received into the main body (30).

In the upper region of the inclined portion (70), the body defines a funnel (110), and the outlet (130) of the body is disposed at the narrow end of the funnel (110). In use, slurry may flow through the body (30) from the inlet (90) towards the outlet (130) within a flow region (120) of the body defined between the inlet and the outlet.

The inclined portion (70) is at an angle of about 70 ° to the horizontal. Within the inclined portion (70), a plurality of spaced apart and substantially parallel corrugated plates (150) are included, each also at an angle of about 70 ° to the horizontal. Each corrugated plate (150) has a plurality of corrugations and thus defines a plurality of peaks (170) and valleys (190) formed by the corrugations.

The respective valleys (190) of adjacent corrugated sheets together form parallel groups of valleys, at which a collector (210) is arranged for collecting, in use, a downward outflow of particles having a density greater than that of the pulp.

Each collector (210) is in fluid communication with a dip tube (290) extending downwardly therefrom for directing heavier particles from the mouth of the collector (210) and out of the body (30) through the dip tube (290).

Fig. 8 shows a longitudinal cross section of two adjacent corrugated plates (150). The upper corrugated sheet is shown cut at the peaks (170) and the lower corrugated sheet is shown cut at the valleys (190). Fig. 8 shows a state in which the space (500) between adjacent plates is completely filled with slurry, which in this exemplary embodiment is a water-based slurry containing high-density particles (530).

If the flow rate is slow enough, the fact that the high density particles (530) are denser than the water will cause them to sink into the water. As the high density particles (530) move downward in the spaces (500) between adjacent plates (150), they will eventually encounter the upper side of the lower plate and will eventually be directed along the upwardly inclined edges of the corrugations towards the valleys (190) of the lower plate. Once the high density particles (530) reach the valley of the lower plate, the high density particles (530) will be directed down the valley, into a collector, and finally out of the device down through the sink pipe.

Claims

1. An apparatus, comprising:

a body defining a slurry flow region and having an inlet and an outlet at respective first and second opposed portions of the body, the slurry flow region extending between the inlet and the outlet;

at least one operatively inclined corrugated plate contained within the body, said corrugated plate comprising at least one corrugation that extends to form one peak or one valley within the slurry flow region;

a collector disposed at an inlet side of the corrugated plate, and:

in association with at least one peak, the mouth of the collector is positioned at an edge of the corrugated sheet to allow particles in the slurry flow region having a lower density than the slurry to rise and be directed along the floor of the peak toward the mouth of the collector; or

Associated with at least one valley, the mouth of the collector being positioned at an edge of the corrugated sheet to allow particles of greater density than the slurry in the slurry flow region to settle and be directed along the upper face of the valley toward the mouth of the collector; and

a tube extending from the collector and beyond the inlet of the body.

2. The apparatus of claim 1, comprising a plurality of spaced apart and operatively inclined corrugated plates contained within the body, each corrugated plate comprising at least one corrugation forming a peak and/or a valley extending within the slurry flow region.

3. The apparatus of claim 2, wherein each corrugated plate comprises a plurality of corrugations forming a plurality of peaks and a plurality of valleys.

4. The apparatus according to claim 3, wherein the valleys of the corrugated sheet are arranged such that high density particles contained within the slurry are directed downwards along the top side of the valleys.

5. The apparatus of claim 4, wherein: (1) the opposing first and second regions of the body refer to the operatively upper and lower regions of the body, respectively; (2) the respective corrugations of adjacent corrugated sheets forming groups of peaks, each group of peaks comprising one collector associated therewith, and the collectors being arranged on the inlet side of the corrugated sheets, the mouths of each collector resting against the edges of the corrugated sheets; (3) each collector is in fluid communication with a respective conduit; and (4) the tube is a standpipe operably extending upwardly from the collector for directing the low density particles from the mouth of the collector and out of the body through the standpipe.

6. The apparatus of claim 5, wherein the standpipe operably extends upwardly from the collector, through the intermediate space and beyond the height of the inlet of the body.

7. The apparatus of claim 6, wherein the collectors are operable to taper upwardly to intersect with respective risers.

8. The apparatus of claim 4, wherein: (1) the opposing first and second regions of the body refer to the operatively lower and upper regions of the body, respectively; (2) the respective corrugations of adjacent corrugated sheets forming groups of valleys, each group of valleys comprising one collector associated therewith, the collector being arranged at the inlet side of the corrugated sheet, the mouth of each collector abutting against an edge of the sheet; (3) each collector is in fluid communication with a respective tube; and (4) the tube is a dip tube operatively extending downwardly from the collector for directing the high density particles from the mouth of the collector and out of the body through the dip tube.

9. The apparatus according to claim 8 wherein the dip tube operably extends downwardly from the collector, through the intermediate space and beyond the level of the inlet of the body.

10. The apparatus of claim 9, wherein the collectors are operably tapered downwardly to intersect with respective sinkers.

11. The apparatus of claim 7 or 10, wherein the body defines an intermediate space between the inlet and the corrugated plate, and the intermediate space comprises one or more baffles positioned transverse to the slurry flow region.

12. The apparatus of claim 11 wherein the body includes an operatively vertical portion and an angled portion downstream of the operatively vertical portion, the inlet is disposed in the operatively vertical portion, and the one or more corrugated plates are disposed in the angled portion.

13. The device of claim 12, wherein the second region of the body funnels into the outlet.

14. The apparatus of claim 13, wherein the operative inclination of each corrugated plate is between 60 ° and 80 ° from horizontal.

15. The apparatus of claim 14 wherein the operative inclination of each corrugated plate is 70 °.

16. The device according to claim 14 or 15, wherein the inclined portion of the body has the same inclination as the corrugated plate.

17. The apparatus of claim 16, wherein the slurry comprises a mixture of water, fly ash, and hollow ceramic microspheres, the low-density particles being hollow ceramic microspheres, the hollow ceramic microspheres being cenospheres.

18. A method of extracting low density particles from a slurry comprising the steps of:

(A) providing a device according to any preceding claim;

(B) receiving a slurry containing low density particles into a body through an inlet;

(C) flowing the slurry along a slurry flow region;

(D) causing the low density particles to rise and be directed along the bottom surface of at least one peak formed by at least one inclined corrugated sheet;

(E) passing the low density particles into the mouth of a collector associated with a peak.

19. A method of extracting low density particles from a slurry comprising the steps of:

(A) flowing the slurry into a body through an inlet and through a flow region comprising at least one operatively inclined corrugated sheet comprising at least one corrugation forming a peak extending along the flow region;

(B) causing the low density particles to rise and be directed along the bottom surface of at least one peak formed by at least one inclined corrugated sheet;

(C) collecting low density particles rising from at least one peak formed by at least one inclined corrugated sheet in one or more collectors associated with each peak;

(D) the low density particles from the collector are operably directed upwardly through the riser to a height above the inlet into the body.

20. A method of separating high density particles from a slurry comprising the steps of:

(A) providing a device according to any one of claims 1 to 17;

(B) receiving a slurry containing high density particles into a body through an inlet;

(C) flowing the slurry along a slurry flow region;

(D) sinking said high density particles and being directed along an upper side of at least one valley formed by at least one inclined corrugated sheet;

(E) the high density particles are caused to enter the mouth of the collector associated with each valley.

21. A method of extracting high density particles from a slurry comprising the steps of:

(A) flowing a slurry into a body through an inlet and through a flow region comprising at least one operatively inclined corrugated sheet comprising at least one corrugation forming a valley extending along the flow region;

(B) sinking said high density particles and being directed along an upper side of at least one valley formed by at least one inclined corrugated sheet;

(C) collecting high density particles sinking from at least one valley formed by at least one inclined corrugated plate in one or more collectors associated with each valley;

(D) the high density particles from the collector are operably directed downwardly through the dip tube to a height above the inlet of the body.