CA1331359C - Use of an apertured endless belt bottom flight catenary and a straight top flight to recover bitumen and materials - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A method and apparatus are provided for the recovery of bitumen and bitumen wetted minerals from a mixture of bitumen, bitumen wetted minerals, water and water wetted minerals. An apertured endless belt has a top flight that is substantially horizontal and above the level of the mixture and a bottom flight that hangs in an inverted arch or catenary and is at least partly immersed in the mixture.
Mixture passes through the belt apertures of the bottom flight and bitumen and bitumen wetted minerals of the mixture adhere to the belt, rise from the mixture as the belt moves, are conveyed to the top flight and fall from there into a receiver beneath the top flight. Heat or jets of fluid are used to help remove bitumen from the top flight and a pump or a bitumen conveyor is used to remove the collected bitumen for further processing.

Description

BACKGROUND OF THE INVENTION i 3 ~ 3 3 ~ 9 The present invention relates to the recovery of bi~umen and bitumen wetted minerals from a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals.
This invention is primarily concerned with the recovery of bitumen and bitumen wetted minerals from mined oil sands, from tailings of mined oil sands plants, from tailings pond sludge of mined oil sands plants, from bitumen or heavy oil and water and minerals mixtures of oil wells, from bitumen and water mixed with ore of mineral mines and from bitumen and water mixed with materials of placer deposits.
Extensive deposits of oil sands, which are also known as tar sands or bituminous sands, are found in Northern Alberta Canada and in many other parts of the world including the USA, Venezuela, and in various countries of Africa and Asia, including the USSR.
The sands are composed of siliceous material with grains generally having a size greater than that passing a 325 mesh screen (44 microns) and a relatively heavy viscous petroleum called bitumen, which at least partly fills the voids between the grains in quantities from 2 to 25 percent of total composition. (All percentages referred herein are in weight percent - unless noted otherwise) Generally the bitumen content of sand that is mined commercially is between 8 and 15 percent. This bitumen contains typically 4.5 percent sulfur and 38 percent aromatics. Its specific gravity at 15 degrees C. ranges generally from about 1.0 to about 1.1. The oil sands also contain clay and silt. Silt is defined as siliceous material which will pass a 325 mesh screen, but which is larger than 2 microns. Clay is material smaller than 2 microns, including some - 1 333 3~9 siliceous material of that size. In some cases the oil sands also contain a small percentage of heavy minerals including ilmenite, rutile, zircon and other metallic minerals.
Much of the world resource of bitumen and heavy oil is deeply buried by overburden. For example it has been estimated that less than 10 percent of the Alberta oil sand deposit is close enough to the earth s surface to be conveniently recovered by surface mining.
The remainder is buried too deeply to be ~conomically strip mined. Hydraulic mining has been proposed for those deposits. However, with current technology, it is considered that enhanced recovery by steam injection, by injection of aqueous solutions, or by in-situ combustion may possibly be more effective for obtaining bitumen from deeply buried formations. ~uch enhanced recovery methods use one or more oil wells that penetrate the formation and stimulate the flow of bitumen or heavy oil to a recovery well. In some cases, the same well may be used to stimulate and recover the resource. Depending upon the procedure employed, enhanced recovery methods generally produce mixtures of water, bitumen and some sand and minerals, and they recover a lower percentage of the bitumen in place than mining methods.
There are several well known procedures for separating bitumen from mined oil sands. In a hot water process, such as disclosed in Canadian Patent No.
841,581 issued 12 May 1979 to Paul H. Floyd et al.; the bituminous sands are jetted with steam and mulled with a minor amount of hot water and sodium hydroxide in a conditioning drum to produce a pulp which passes from the conditioning drum through a screen, which removes debris, rocks and oversize lumps, to a sump where it is - diluted with additional water. It is hereafter carried into a separation cell. In the separation cell, sand ~: :" ~

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1~3~ 9 settles to the bottom as primary tailings which are discarded. Bitumen rises to the top of the cell in the form of a bituminous froth which is called the primary froth product. An aqueous middlings layer containing some mineral and bitumen is formed between these layers. A scavenging step is normally conducted on this middlings layer in a separate flotation zone. In this scavenging step the middlings are aerated so as to produce a secondary tailings product, which is discarded, and a secondary froth product.
The secondary froth product is thereafter treated to remove some of its water and mineral matter content and is thereafter combined with the primary froth for further treatment. This combined froth typically contains about 52 percent bitumen, 6 percent minerals, 41 percent water, all by weight, and may contain from 20 to 70 volume percent air. It resembles a liquid foam that is usually treated with steam to improve its flow characteristics for subsequent processing. The primary and secondary tailings products are usually combined and water may be added to enhance the pipeline disposal of this combined tailings stream called the extraction tailings.
The high water and minerals contents of the combined froth product normally are reduced by diluting it with hydrocarbon diluent such as naphtha. It is then centrifuged to produce a tailings product, called the centrifugal tailings, and a final bitumen product that typically contains essentially no water and less than 1.0 percent solids, from which the naphtha is recovered and then is suitable for coking, hydrovisbreaking or other refining techniques to produce a synthetic crude oil. The centrifugal tailings, containing some naphtha, bitumen, silt, clay and heavy minerals are discarded.

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There are basically three effluent streams from the hot water process. Each carries with it some of the bitumen from the feed; thereby reducing the efficiency of the process. These include the oversize materials coming from the screen, the extraction tailings and the centrifugal tailings. Up to 10 percent of the bitumen in the original feed and up to

2.5 percent of the naphtha stream may be lost in this manner. Much of this lost bitumen finds its way into large retention ponds or tailings ponds that are typical of the hot water process. The bottom of such retention ponds may contain from 20 to to 50 percent dispersed mineral matter consisting substantially of clay and silt as well as 2 percent or more bitumen.
As disclosed in Canadian Patent No. 975,697 issued on 7 october 1975 to David H. James this part of the pond contents, referred to as sludge, or tailings pond sludge, is a potential source of recoverable bitumen.
In the hot water process the heavy minerals present in the oil sand ore, such as rutile, ilmenite and zircon, tend to be attracted to and wetted by the bitumen of the oil sands during processing, and these heavy minerals are recovered in the combined bitumen froth product. The minerals are removed from this bitumen product in the dilution centrifuging step and are part of the centrifugal tailings of the hot water process.
I have found that the extraction tailings from the hot water process also contain heavy minerals. These heavy minerals are in association with and are wetted by the bitumen that is discarded with the extraction tailings. I havè discovered that this residual bitumen generally contains a higher percentage of heavy minerals than the bitumen froth produced by the hot water process. I have concluded that most of the bitumen that remains with the extraction tailings of

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the hot water process is there because this bitumen does not float as readily as the bitumen that is recovered. The increased amount of minerals associated with this bitumen make it denser and more difficult to float than the bitumen that is normally recovered in the flotation steps of the hot water process. Then, when this residual bitumen is recovered from these extraction tailings by a process, such as in the present invention, which does not rely on flotation alone, the resulting bitumen product will contain a large percentage of heavy minerals.
When Alberta oil sands are mixed with water and are separated with the present invention, the bitumen product contains heavy minerals which are bitumen wetted and the water phase contains sand, silt and clay that are water wetted. When extraction tailings from a hot water process are separated with the present invention to recover the residual bitumen, the bitumen product from that separation contains heavy minerals which are bitumen wetted and the water phase contains sand, silt and clay that are water wetted. Similarly, when tailings pond sludge is separated with the present invention, the bitumen product from that separation contains heavy minerals which are bitumen wetted and the water phase of the sludge contains silt and clay that are water wetted. In the present invention therefore, when a mixture is separated, the bitumen wetted minerals are recovered along with the bitumen phase and the water wetted minerals are discarded with the water phase. As more bitumen is recovered from such a mixture, more heavy minerals are recovered from the mixture as well.
The present invention therefore serves to recover bitumen and also to concentrate heavy minerals from a mixture by capturing these with the bitumen product in the separation process. These minerals are released ., , .. , ., ,,, . , . , ., . , , . , .. ~ . "

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when the bitumen product is diluted and centrifuged, or when the bitumen is removed from these minerals in some other way. This concentration process is a secondary bonus of the present invention that may make it possible to economically recover useful minerals from mined oil sands, tailings or sludge, even if the original oil sands ore contains only traces of useful minerals.
Heavy minerals are found in small concentration of about 1% in the Alberta oil sands. Oil sands from other locations may contain traces of other types of minerals, including gold, silver, platinum and other useful or precious minerals. These minerals in many cases are or become bitumen wetted in the process of the present invention and are recovered with the bitumen product. They can be separated from that bitumen to yield a minerals by-product of the bitumen extraction process.
The present invention may also be used to recover useful minerals from other ores. Bitumen and water may be mixed with ore from a mine to cause the minerals of the ore to become bitumen wetted while the gangue becomes water wetted. In a subsequent separation by the present invention of this ore-bitumen-water mixture, the resulting bitumen product will contain bitumen wetted mineral of the ore for recovery, and the water effluent will contain water wetted gangue of the ore to be discarded. On other occasions bitumen and, if xequired, water may be mixed with a placer deposit of minerals, metals or precious stones to cause these to become bitumer w~tted and the gangue tc remain water wetted. In subsequent separation, by the present invention of this placer deposit mixture, the resulting bitumen product will contain bitumen wetted minerals, metals or precious stones of the placer deposit for recovery, and the water effluent will contain water - ~3~

wetted gangue of the placer deposit for disposal.
The useful minerals, metals or stones are subsequently recovered by removing the bitumen and the residue separated into components by mineralogical methods.
The mineral recovery aspects of the present invention may in time compete with conventional minerals froth flotation, with the added advantage that mineral particles of larger size may be recovered more efficiently.
BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to the recovery of bitumen and bitumen wetted minerals from a mixture of bitumen, water, water wetted minerals and bitumen wetted minerals.
In one aspect, the invention provides a method for the recovery of bitumen and bitumen wetted minerals from a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, which method comprises passing through the mixture an apertured endless belt whose path includes a bottom flight that passes through the mixture and a top flight ~hat passes : above the surface of the mixture, whereby bitumen and bitumen wetted minerals adhere to the bottom flight of the apertured belt as the belt passes through the : mixture and emerges from the mixture, and bitumen and bitumen wetted minerals fall from the top flight of the apertured belt into a receiver located under the top flight.
In another~aspect the invention provides an apparatus for the separation of bitumen and bitumen wetted minerals from a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, which apparatus comprises:

133~ 3r~9 a~ a container for containing a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, b) a movable apertured endless belt supported in such a manner that its path includes a top flight that is substantially horizontal and is above the normal level of mixture in the container, and a bottom flight that extends down to below the said normal level so that a portion of the bottom flight is in the mixture during operation of the apparatus, c) a receiver located beneath the top flight of the apertured belt to receive bitumen which in operation falls from the belt, which receiver is provided with an outlet for removal of bitumen, d) means to revolve the endless belt, whereby in operation bitumen and bitumen wetted minerals adhere to the apertured belt as the belt rises from the mixture and bitumen and bitumen wetted minerals fall from the top flight of the apertured belt into the receiver located beneath the top flight of the belt, and water and water wetted minerals pass through the apertures in the bottom flight of the apertured belt.
In preferred embodiments the mixture is separated with an apertured oleophilic endless moving belt of novel design consisting of a top flight that i9 generally straight and horizontal, and a bottom flight that is in, or approximates to, the form of an inverted arch or catenary. The endless helt is supported by at least two shafts or rollers, that preferably keep the top flight under tension, while the bottom flight is allowed to hang down from these shafts or rollers in the form of an inverted arch. The bottom flight is part of the separation zone and is at least partly immersed in the mixture it is separating. Mixture is passed to the apertured oleophilic endless belt in the separation zone such that the bitumen and bitumen - : , 3~ 3~
wetted minerals adhere to the belt surfaces, while the water and water wetted minerals pass through the belt.
The flow of mixture through the belt preferably is from the inside of the arch to the outside of the arch.
This is accomplished by introducing the mixture for separation into the arch inside and by withdrawing mixture from outside the arch after the mixture has passed through the belt. The flow of mixture through the belt may also be from the outside of the arch to the inside of the arch. This is accomplished by introducing to or allowing mixture to flow to the belt from the outside of the arch for separation and withdrawing mixture from the arch inside after it has passed through the belt.
In at least one case described in these specifications of the invention the flow of mixture through the apertures may be in either or both directions, when the invention is used to recover bitumen mats from tailings pond sludge with a floating barge.
The surfaces of the moving endless belt of the present invention are oleophilic and therefore capture bitumen and bitumen wetted minerals from the mixture in the separation zone as these come in contact with said surfaces, while water and water wetted minerals flow through the belt apertures. These captured bitumen and bitumen wetted minerals are carried or conveyed by the moving belt via the bottom flight to the top flight.
The top flight is part of the recovery zone of the belt. The bitumen and bitumen wetted minerals are removed from the belt top flight and are collected in a receiver mounted under the top flight. They fall off the belt by gravity, with or without the help of heat, or are blown off the belt.

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The present invention is an improvement over my Canadian Patent No. 1,1~9,363 which in the embodiment of Figure 2 also used an apertured oleophilic endless belt supported by two conveyor end rollers to recover bitumen from an oil sands mixture. In this prior patent the top and bottom flights were generally parallel and both were inclined whereas in the present invention the endless belt has a unique shape that results in more effective capture of bitumen and bitumen wetted mineral from the mixture by the belt and more effective removal of bitumen and bitumen wetted miDeral from the belt. The new and unique shape of the endless belt makes it convenient to use a lower temperature in the separation zone along the bottom flight and to use a higher temperature in the recovery zone along the generally horizontal top flight. The new and unique shape of the belt also encloses a larger volume of mixture inside the bottom flight and provides for convenient distribution of mixture over the width and length of the belt in the separation zone.
Combination of all these improvements was not convenient nor considered in the prior art.
In the prior art the distribution of mixture over the full width and length of the belt in the separation zone was not as effective. There was no difference in temperature between the separation zone and the recovery zone and the top flight and the bottom flight of the endless belt were generally parallel. In the prior art bitumen was recovered from the belt by the use of transfer rollers that forced bitumen into and upwards out of the apertures. Transfer rollers are not needed in the present invention and this reduces wear and tear on the belt. The new invention also makes it possible to use apertured oleophilic belts that are at least twice as thick as the belts used in the prior art, which are more efficient for bitumen capture, but " ~ ' :~ '' ~ ':

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which could not be effectively used in the design of the prior art.

DRAWINGS

The invention will be further illustrated with reference to the accompanying drawings showing, by way of example, embodiments of the invention in which:
Figure 1, in accordance with the invention, is a perspective view of the preferred shape of the apertured oleophilic endless belt supported by two end rolls and provided with a bitumen collection tank.
Figures 2 and 3 are a schematic sectional end and side views of a typical separator, showing the unique shape of the endless belt and, illustrating the various components of the present invention.
Figures 4, 5 and 6 are illustrations of three types of apertured oleophilic endless belts suitable for use in the present invention.
Figure 7, 8, 9 and 10 are schematic views of variations of the new and unique shape of the endless belt to accomplish the objectives of the invention.
Figure 11 is an illustration of a barge floating on a tailings pond in an embodiment of the invention - for collecting bitumen mats from tailings ponds.
Figure 12 is a schematic illustration of the top `-flight in an embodiment of the present invention using -~ a heat radiator in the form of a bank of pipes to remove bitumen and minerals from the belt in the recovery zone and fans to help blow bitumen from the top flight.
Figures 13, 14, 15, 16, 17 and 18 are illustrations of various methods for heating the belt ~- and its adhering bitumen with electric power in the recovery zone to remove bitumen and bitumen wetted -~- minerals from the belt.

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Figures 19, 20, 21, and 22 are illustrations of a bitumen conveyor to move bitumen product of the present invention from the recovery zone to subsequent processing.

DETAILED DESCRIPTION OF THE INVENTION

. _ _ For the purpose of the present invention, bitumen is defined as a hydrocarbon that at 15 degrees C. has a viscosity between 1000 and 50 million centipoises. It may include conventional bitumen, conventional heavy oil, tar, wax and asphalt, or any other thick or viscous petroleum or oil based fraction or product, as well as residues from land or marine oil spills.
Bitumen wetted minerals are defined for the purpose of the present invention as any number of mineral particles at least a portion of whose surface areas are oleophilic and covered by bitumen, or have become oleophilic and covered by bitumen due to exposure to bitumen and water. When the surface area portion covered by bitumen of a mineral particle is large enough to cause adhesion of this particle on contact to bitumen on a mechanical surface, such as a belt, the mineral particle is considered to be bitumen wetted for the purpose of the present invention.
Water wetted minerals are defined for the purpose of the present invention as any number of mineral ~- particles most of whose surface areas are hydrophilic and covered with water or have become hydrophilic and covered with water due to exposure to bitumen and water, which mineral particles have no bitumen on their surfaces, or the surface portions of the particle covered by bitumen are not large enough to cause these ; mineral particles to adhere to bitumen on a mechanical surface on contact.

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It is to be understood that the present invention is used to separate bitumen and bitumen wetted minerals from water and water wetted minerals, no matter from where they originate. ~ mixture for separating, that contains bitumen, water, bitumen wetted minerals and water wetted minerals, may already exist in that form;
or it may be prepared as part of the separation objective prior to the actual separation by the present invention.
For example, mined oil sands tailings and tailings pond sludge are mixtures that normally contain bitumen, water, bitumen wetted minerals and water wetted minerals; and these may be separated in the form they are normally produced or normally exist. On the other hand, oil sands, as mined, normally contain only very small amounts of water or no water at all. Water needs to be added to and mixed with such oil sands to prepare a mixture suitable for separation by the present invention. In some cases heat and/or mechanical energy needs to be added as well to the oil sands, along with the water; and this mixture needs to be tumbled and screened to digest the lumps of oil sands in water and to remove debris, rocks and oversize lumps before it can be separated by the present invention.
Furthermore, both water and bitumen may be added to mineral mine ores, and the resultiny mixture tumbled, mixed, ground and screened before these ores are suitably separated into bitumen wetted minerals and water wetted gangue. In a similar way, bitumen and perhaps water may be added to placer deposits, tumbled and screened, and perhaps ground, before it is suitably separated into bitumen wetted minerals and water wetted gangue with the present invention.
I have found that when a mixture of bitumen, bitumen wetted minerals, water and water wetted minerals is passed to an apertured oleophilic wall in a ~33~.3~
separation zone, the bitumen and bitumen wetted minerals will cling to this wall when they come in contact with it but the water and the water wetted minerals will pass through the wall apertures. When this wall is stationary, only a relatively small amount of bitumen and bitumen wetted minerals can be collected in this manner since the bitumen and bitumen wetted minerals accumulating on the wall surfaces will close the apertures. However, when the wall is moving, and bitumen and minerals are removed from the wall, more mixture can be separated in this manner without danger of closing the apertures. Furthermore, when the wall is a continuously revolving endless belt that has at least one zone for separation and at least one zone for removing the clinging bitumen and bitumen wetted minerals from the belt surfaces and out of the belt apertures, the process becomes continuous and large amounts of mixture can be separated per day or per year by the moving belt on a continuous basis.
I ~ave found that optimum separation is achieved by an apertured oleophilic belt if the separating mixture is evenly distributed over the whole belt area, and can flow uniformly and slowly to the belt surfaces and through the belt apertures at a temperature that is optimum for adhesion of bitumen to bitumen on the belt surfaces, and under conditions that allow the bitumen and bitumen wetted minerals to remain clinging to the belt surfaces until these surfaces reach the recovery zone. This optimum desirable temperature may vary with the type of mixture being separated, but it may be optimized in the~process of the present invention for each mixture. The mixture suitably has a temperature between zero degrees centigrade and eighty degrees centigrade, preferably between zero degrees centigrade and forty degrees centigrade. The viscosity of the bitumen in the mixture is suitably between 10,000 and r', ~:', ' , . . . , ' ' , ' : ~:

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5,000,000 centipoises, preferably between 150,000 and 1,500,00 centipoises.
The separation zone of the present invention is along the bottom flight of an apertured oleophilic endless moving belt that hangs in the form of, or approximates to, an inverted arch or catenary and is at least partly immersed in the mixture under separation, while the recovery zone is along the generally straight top flight of this same endless belt. End walls, and sometimes baffles on those walls~ may be placed along the belt edges in the separation zone to reduce flow of mixture past the belt edges and to increase flow through the belt apertures.
One preferred belt configuration of the present invention is illustrated in perspective in Figure l.
The endless belt (l) has a bottom flight (2) and a top flight (3) and is supported by at least one roller (4) or stationary belt guide at the beginning of the top flight ~3) and one roller (5) at the end of the top flight. This last roller (5) is a drive roller that keeps the top flight generally straight and in tension.
The bottom flight (2) i5 not straight but hangs down from those two rollers (4 and 5) in the form of an inverted arch or catenary and is immersed in the mixture ~8) it is separating. The direction of movement of the belt is illustrated with an arrow (9).
A receiver (7) is mounted under the top flight (3) to collect bitumen and bitumen wetted minerals that slough off the top flight(3).
More details are provided in Figures 2 and 3 which represent an end view (Fig. 2) and a sectional side view ~Fig. 3) through line S-S of a separator using the belt configuration of Figure l. The endless belt (1), consisting of a steel process belt, is supported by a stationary belt guide or a revolving idler roller (4) and a shaft (6) with sprockets (5) that have teeth (10) ., . - - ,... ~ ~ . , -that drive the belt (1) and cause the top flight (3) to be dragged over flat bar grating (15) mounted under the top flight with the bars diagonal to the direction of the belt movement in the recovery zone (13)~ The bottom flight t2) hangs down from the roller (4) and the sprockets (5) in the form of a catenary and is immersed in the mixture (8) it is separating. Mixture (8) flows into the inside of the catenary of the bottom flight (2~ through an inlet pipe (16), passes through the apertures of the belt (1) and leaves from the separating zone (12) enclosure, surrounding the catenary, though an exit pipe (17). Bitumen (not shown) and bitumen wetted minerals are captured by the surfaces of the bottom flight (2) as the mixture passes through the apertures of the endless belt~
The bottom flight (2) emerges out of the mixture (8) and is sprayed with a fog of cold water by a bank of nozzles (14) to wash water wetted minerals from bitumen on the surfaces of the belt (1~ before these surfaces, covered with bitumen and bitumen wetted minerals move onto the top flight (3). One or more banks of nozzles (11) spray hot water onto the bitumen and bitumen wetted minerals (not shown), that are conveyed by the top flight, to reduce the bitumen viscosity and cause the bitumen and minerals to slough off the top flight (3) and fall into the receiver (7) under the top flight (3). The resulting bitumen and minerals product (35) collecting in the receiver (7) leaves this receiver through an exit pipe (18) After passing through the recovery zone, the be~t surfaces return to the separation zone to ;capture additional bitumen. These belt surfaces, returning to the separation zone, normally are still covered with a thin layer of bitumen that makes subsequent capture of bitumen and bitumen wetted minerals in the separation zone more effective. This layer of bitumen also serves ,,- , ~:
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to reduce abrasion of the belt by the mineral particles of the mixture, and reduces or eliminates corrosion of the belt surfaces.
In most cases the mixture for separation is pumped into the inside of the catenary where it can distribute over the ull belt width and over the full length of the immersed portion of the belt flight before it flows to the belt and through the belt apertures. As a result, the velocity of mixture through the belt (2) apertures generally is less than 20 centimeters per second and preferably is as low as 2, or even 0.5 centimeters per second, or lower, to optimize contact, adhesion and accumulation of bitumen and bitumen wetted minerals to the belt (2) surfaces in the separation zone.
Bitumen and water have approximately the same specific gravity, but minerals are usually more than twice as dense as water. For many mixtures, that are separated with the present invention, the bitumen product contains some minerals and is lighter than, or is of about the same specific gravity as, the mixture being separated. Therefore, there are at least two reasons why immersing the bottom belt flight in the separating mixture is beneficial. In the first place, it helps to slow down the flow of mixture (8) through the belt apertures (45) and makes it easier for the bitumen and bitumen wetted minerals to adhere to the belt surfaces. In the second place, it helps to keep the bitumen and bitumen wetted minerals adhering to the belt (1) in the separation zone (12) after they have been captured by the bottom flight (2).
Immersion of the bottom flight (2) in the mixture gives the bitumen and the bitumen wetted minerals a buoyed density and reduces the effect of the force of gravity in the separation zone (12). This makes it easier for bitumen and mineral to adhere to the belt ;, b, ~33~ 3~

and to remain adhering to the belt until removed from the separation zone. Only in the unimmersed portion of the separation zone (12) does the force of gravity have its full effect on the captured bitumen and bitumen wetted minerals. However, as may be seen from Figures 1 and 2, the slope of the catenary bottom flight where it is not immersed is very steep and, instead of falling off the belt, the bitumen and bitumen wetted minerals flow down the catenary under the force of gravity. This is shown more clearly in Figure 12 where bitumen and minerals (37) are shown on the belt. When the velocity of the belt (2 and 3) is kept higher than the velocity of bitumen and minerals (37) flowing down the catenary in the unimmersed portion of the bottom flight (3), the net result is an upward conveyance of bitumen and minerals (37) from the separation zone (12) into the recovery zone (13). This is in contrast with the prior art of Canadian Patent No. 1,129,363 where the belt flights, supported by two conveyor end rollers were generally straight and were at about the same slope whether immersed or not. As a result, in the prior art there was more tendency for bitumen to fall off the belt in the separation zone after it emerged out of the mixture and before it reached the recovery zone, and this limited the operating conditions in the prior art.
In the embodiment of Pigures 2 and 3 the shaft (6) with sprockets (5) is driven by an electric motor (20) with a belt or chain (21) and a gear box (19) to provide the desired belt speed in the desired direction (9). The speed bf the belt can be controlled by speeding up or slowing down the electric motor and/or by selecting the ratio of the gear box (19) or of the belt or chain (21) pulleys. Belt speed is normally controlled to be as slow as possible to capture as much as possible of the bitumen from the mixture, and to , :: ,- . ~ ~ i .. ~ . . . . .. .

give the top flight as much time as possible for the bitumen to slough off the belt. However, it must be kept fast enough that sufficient open apertures are available in the immersed portion of the bottom flight (2) in the separation zone to permit flow of mixture through the belt without major difficulty. It must also be fast enough to prevent flow of bitumen down into the separation zone along the unimmersed portion of the bottom flight. The preferred belt speed is between 1 centimeter per second and 100 centimeters per second. The belt preferably revolves continuously, but it may also be made to revolve intermittently when more time is required for collecting of bitumen by the belt in the separation zone.
The temperature of the mixture (8) in the separation zone (12) may be optimized for optimum capture, adhesion of bitumen to bitumen and to the belt surfaces, and for retention of bitumen and bitumen wetted minerals by the bottom flight (2) However, the selected separator temperature may also be based on economics when mixtures are available for separation colder or warmer than the optimum bitumen adhesion and retention temperature. In that case the mixture may be cooled or heated somewhat to approach the optimum bitumen adhesion and retention temperature, or the mixture may be separated with the present invention at the temperature at which it exists.
For example, extraction tailings coming from a mined oil sands plant may be too warm for optimum adhesion of bitumen to bitumen on the bottom flight ~3) of the endless belt. But cooling such a stream may be more expensive than operating the present invention at less than optimum separation temperature. In that case, it may be more economical to operate the belt of the present invention at a faster speed and/or to pass , . , :

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the mixture through two or more separators in cascade, rather than to cool the mixture.
Conversely, tailings pond sludge from a mined oil sands plant may be available from a tailings pond just above freezing. Heating such a sludge to the optimum bitumen adhesion temperature of the present invention may be more costly than reducing the flow of mixture through the bottom flight (2) by using a larger belt (lJ to achieve the same production of bitumen and minerals. Optimum adhesion and retention temperatures for bitumen are determined by practice and experience and vary widely with bitumen viscosity and with other bitumen properties.
The temperature in the recovery zone (13) of the present invention in many cases is set higher than the temperature in the separation zone. This is done to speed up the sloughing off of bitumen from the top flight (3). In some cases, however, this temperature may be the same as the temperature of the mixture in the separation zone (12). The top flight is not immersed, is horizontal, and may be, but does not have to be, dragged over a grating or over a bank of pipes.
The captured bitumen sloughs of the belt in the recovery zone much more readily than in the separation zone where the belt is immersed in a mixture that buoys up the bitumen, or where the belt when not immersed moves upward in an almost vertical direction.
One of the unique features of the present invention is the difference in shape between the top and the bottom flights of the belt and the partial immersion of the bottom flight only, which features combine to optimize bitumen capture and retention by the belt in the separation zone and bitumen removal from the belt in the recovery zone. A unique and separate feature of the present invention is the ability to operate the recovery zone at a temperature 3~ 3~
that is different from the temperature of the separation zone. It allows for optimization of separation zone conditions for optimum capture and retention of bitumen and bitumen wetted minerals by the bottom flight of the belt, and for separate optimization of recovery zone conditions for optimum release of bitumen and minerals from the top flight of the belt.
Nozzles (11) may be used to spray cold, warm or hot water, steam or other gas onto the top flight and thereby blow bitumen and minerals from the top flight (3). When the fluid from those nozzles is cold, high pressure is required to achieve the desired bitumen removal. Lower pressures may be used for bitumen removal when the fluid is warm or hot, because warm fluid reduces the bitumen viscosity and facilitates its removal from the top flight. Alternately the nozzles (11) may be used to spray cold or hot solvent onto the top flight that mixes with and dilutes the bitumen to cause it to slough off the top flight more readily .
Furthermore, hot water, steam or other hot fluid may be used in a bank of pipes under the top flight, in stead of grating, to support the top flight and to cause the bitumen on the top fiight to heat up and reduce in viscosity to cause the bitumen and minerals to more readily slough off the top flight (3). Alternately, a heat radiator or a bank of heated pipes may be mounted above the top flight to heat the top flight and help the bitumen to slough off the belt. This is further illustrated in Figure 12.
The preferred apertured oleophilic belts for the present invention are metal process belts. Three types of such belts are illustrated in Figures 4, 5 and 6.
The first belt resembles a multi- strand roller chain belt and is illustrated in Figure 4. It consists of a large number of flat linkages (26) and rollers (28) . , , , - , ~ .
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. , . . ,, ~, . . . . . .
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that are joined by cross rods ~27) to form an endless belt. The linkages (26) contain at least two holes (30) each. The cross rods (27) are threaded through these holes (30) in the linkages and holes in the rollers (28) to join the linkages into a continuous belt and to provide proper parallel spacing for the linkages. The apertures (45) of this belt are the volumes enclosed by the rollers (28) and the linkages (26). Sprockets, that engage with the rollers may be used to drive the belt, or ~riction rollers contacting the linkages may be used for that purpose. The flat linkages and the rollers may be made from an oleophilic metal or material, or the complete belt, or the linkages and/or rollers separately may be covered with an oleophilic coating. Uncoated unalloyed steel is somewhat oleophilic and, with most mixtures, attracts bitumen.
The affinity of the belt for bitumen can be enhanced by coating the steel surfaces with tin, polyolefin, neoprene, urethane, elastomer or any other oleophilic abrasion resistant coating. Alternatively, the steel from which the belt is constructed may be a high carbon steel alloy that, at the pH of the mixture, has an affinity for bitumen.
The determination of whether a particular material is oleophilic in the presence of a particular mixture is a well established art or science, in which the contact angle of a drop of bitumen adhering to the material submerged in the mixture is measured. The smaller this angle of contact, the greater the affinity of bitumen for this material in the presence of this mixture,and hence, the more suitable it is for capturing bitumen from the mixture.
There is a great ~ariety of materials that are more or less oleophilic in a great variety of mixtures and the oleophilic nature of some materials varies somewhat depending upon the pH of the environment. If , :. , ~ :

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the mixture to be separated is of low pH some materials may be preferred and if the material to be separated is at neutral pH or high pH other materials may be preferred. A person skilled in the art should be able by simple experiment and without exercise of any inventive faculty to determine which materials operate best with particular mixtures to be separated. Anyone skilled in the art will also be able to determine which materials have the necessary strength and abrasion resistance to last long enough to make them suitable for use in the present invention. Linkages (26), rollers (28) and cross rods (27) formed from high carbon steel, for example, make a strong, abrasion resistant belt suitable for separating several mixtures with the present invention.
A second preferred belt is illustrated in Figure . It is comprised of a large number of flat strips (29) of metal, each formed into a shape resembling approximately a square wave pattern with sloping sides.
Two holes (30) are near the top and two holes are near the bottom of each square wave to accept metal cross rods (27) that pass through the holes (30) and join the metal strips (29) into a continuous metal belt. The apertures (45) in this belt are those areas enclosed by the flat strips (29) and the cross rods (27). This construction results in a strong very flexible belt resembling a multitude of hinges formed into an endless belt. The flat strips (29) and/or the cross rods (27) may be made fxom an oleophilic metal or material, or the complete belt, or the metal strips and/or cross rods separately may be covered with an oleophilic coating. Flat strips (29) and cross rods (27) formed from steel or a steel alloy, for example, make a strong belt suitable for separating several mixtures with the present invention.

.
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One of the conveyor roller supports of the belt may be a conventional conveyor end roller that idles or is driven, or it may be a stationary belt guide, while sprockets mounted on a drive shaft, which engage the cross rods (27) may provide a driven support for the belt. Alternately, instead of on a shaft, sprocket teeth may be mounted on a driven roller to drive the belt. Friction rollers may be used instead to drive the belt by contacting the surfaces of the flat strips (29) with the surface of the friction rollers.
A third preferred process belt, illustrated in Figure 6, consists of a large number of metal wires (31) that are formed into spirals and that are joined by cross rods (27). Again the belt consists of a multitude of hinges formed into an endless belt. The loops of one spiral are meshed with the loops of a second spiral and a cross rod (27) is pushed through the meshed loops to join these two spirals into a hinge. Then the loops of a third spiral mesh with the loops of the second spiral. A second cross rod (27) is pushed through those meshing spirals to form a second hinge. This is continued until a large belt is assembled consisting of hundreds of spirals (31) that are joined with cross rods (27) into hundreds of hinges to form a long belt. Then, the first spiral is joined with a cross rod to the last spiral to form an endless belt. The apertures (45) in this belt are the areas enclosed by the spirals (31) and the cross rods ~27).
The spirals and/or the cross rods may be made from an oleophilic metal or material, or the complete belt or the spirals and~or the cross rods separately may be covered with an oleophilic coating. Spiral wires (31) and cross rods (27) formed from steel or a steel alloy, for example, make a strong belt suitable for separating several mixtures with the present invention. One of the conveyor supports of the belt preferably is a conventional conveyor end roller that idles or is driven, but it may also be a stationary belt guide. A
pin roller, mounted on a drive shaft which pins engage the spirals and cross rods of this type of belt, may be used to drive it and provide the second support for the belt. Alternately the belt may be driven by friction.
Mesh belts or other types of flexible process belts made from metal and/or from other strong materials that are oleophilic or that are coated with an oleophilic material may be used as well for the endless belt of the present invention. Unlike the prior art, which relied on bitumen transfer rollers that were found to require thin belts to be effective, the present invention allows the use of thicker belts.
In the prior art belt thicknesses hardly ever exceeded a few millimeters, whereas in the present invention the belt thickness preferably may range from a few millimeters to several centimeters. These thicker belts can capture and carry more bitumen and bitumen wetted minerals per square area of belt in the separation zone and can shed bitumen more effectively in the recovery zone by the use of heat, the force of gravity and/or jet pressure, which was not disclosed in the prior art described in Canadian Patent No.
1,129,363.
Belt surfaces that are oleophilic and that are covered with a thin or a thick layer of bitumen may be considered to be coated with an oleophilic coating because bitumen is oleophilic under the conditions used in the present invention, and bitumen in the mixture under separation adheres to the bitumen layer on the belt upon contact. ~elt surfaces returning from the recovery zone to the separation zone in the present invention normally are covered with a thin layer of bitumen.

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~ -J~j 3~j3 Various configurat~ons of endless belt are illustrated in Figures 7 to 10. The simple form of belt of Figure 1 is shown schematically in Figure 7. A
third roller (25) or stationary belt guide is shown in Figure 8. The purpose of this roller (25) is to prevent swinging of the bottom flight. When the bottom flight (2) is constrained in this manner, it is easier to add some baffles to the separation zone front and rear walls to reduce flow of mixture past the belt edges and to cause more of the flow to go through the belt apertures. This third roller (25) deforms the catenary but the bottom flight (2) still approximates I to an inverted arch or catenary. However, immersed bearings will be required that may be difficult to maintain. Immersed bearing will not be required when a stationary belt guide is used in stead of the third j roller; the belt will slide over a portion of the surface of this guide, and this will result in some abrasion.
One type of friction drive for the belt of the present invention is illustrated in Figure 9. In this case the drive roller (5) may be larger than the idler roller (4) and a third roller (24) may be used to increase the wrap of belt around the drive roller (5) to provide pressure for friction and/or to give more contact between the roller (5) surface and the belt.
In addition, the drive roller (5) may be lagged with rubber or plastic to increase the coefficient of friction with the belt. Longitudinal bars (25) pipes or rollers may be mounted in the separation zone on the outside or, preferably and as shown on the inside of the catenary to reduce swinging of the bottom flight while retaining bitumen inside the catenary for capture ; by the belt. When these bars are mounted on the inside of the catenary, and the flow of mixture is from the inside to the outside, any bitumen that rubs off the ~ ~ ~3~ 3~

belt and adheres to these bars is not lost but will eventually find its way back to the belt. Conversely, when the bars are mounted on the outside of the catenary, there is potential for loss of bitumen from those bars to the mixture that leaves the belt.
In some cases where it is desirable to increase the length of the top flight to give bitumen more opportunity and time for sloughing off of, the top flight may be doubled or tripled in length by installing additional rollers to train the belt to resemble two or more sequential top flights. This is illustrated in Figure 10 where two additional rollers

(4) provide for two top flights in the recovery zone, in stead of one.
On other occasions it may be desirable to add two rollers or stationary belt guides to the separation zone to deform the catenary and make it assume the shape of a rectangle. This is also illustrated in Figure 10. The one or two rollers or stationary pipes (25) can provide a vertical slope for the unimmersed portion of the rising bottom flight (2) to reduce any sloughing off of bitumen in the separation zone of Figures 8 and 10.
The recovery zone of a typical configuration of the present invention is shown in Figure 12 in enlarged form. The belt used for this Figure is a spiral process belt of Figure 6, but other types of belt may be u~ed as well for the recovery zone of Figure 12.
Specifically the endless belt configuration used for this illustration resembles Figure 7. The drive roller

(5) is a pin roller with pins (10) that engage with t~he spirals (31) and cross rods (27) of the belt.
Bitumen and bitumen wetted minerals conveyed by the belt out of the separation zone (12) and into the recovery zone (13) may carry with them an undesirable amount of water wetted minerals. As illustrated in , ~ , :, , . : .

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Figure 12, some of these water wetted minerals may be removed by spraying a mist of water from a bank of nozzles (14) onto the belt in the unimmersed portion of the bottom flight (2). Such a mist of water dilutes the mineral content of the water wetted minerals carried by the belt and causes a portion of them to flow back down into the separation zone (12). Proper selection of nozzles and water pressure is reguired to produce a mist that is fine enough and with a force of water from the nozzles (14) that is not so large as to cause bitumen and bitumen wetted minerals to be blown from the belt before they are conveyed to become part of the top flight (3). Removal of water wetted minerals from bitumen and from bitumen wetted minerals on the bottom flight of the belt (2) in this manner results in a bitumen product (35) in the recovery zone that contains a lower percentage of water wetted minerals.
The top flight of Figure 12 is supported by a flat bar grating (15) while a bank of heated pipes (34) is mounted above the belt that causes the top flight and the bitumen and minerals on that top flight to heat up. For effective belt tracking, this grating is mounted under the belt diagonally in a chevron pattern, with the diagonal bars joining near the middle of the belt width. The heat of the pipes warms up the enclosed space in the recovery zone (13) and warms up the bitumen and minerals on the top flight by radiation and convection. This warming up causes a reduction of bitumen viscosity in the recovery zone and results in a rapid sloughing off of bitumen and miDerals from this top flight and into the receiver (7) under the top flight. This receiver is partly immersed in the separating mixture ~8) but it is double walled, with insulation (43) between these walls, so that very little heat is transferred from the bitumen and minerals product (35) in the receiver (7) to the mixture (8) in the separation zone. The product (35) from the recovery zone therefore retains its heat and its reduced viscosity, and is readily pumped from the receiver (7). The recovery zone (13) is enclosed to prevent loss of heat or vapors, and it may be vented or placed under negative ox positive gauge pressure, as desired.
The roof structure of the recovery zone may be provided with air ducts for ducting air under pressure to blow residual bitumen from the top flight.
Alternately, motors and fans may be used to blow bitumen from the belt surfaces after they have passed the radiator. This is illustrated in Figure 12 where a multitude of fan blades (39) and electric or hydraulic motors (38) are used to circulate air through the top flight (3) to improve heat circulation or convection in the recovery zone. These fans blow bitumen from the belt, from the top flight (3~ surfaces before they return to the bottom flight (2).
Electric power may be used as well to heat the top flight and remove bitumen and bitumen wetted minerals from the top flight in the separation zone. This is illustrated in Figures 13 to 18. In Figures 13 and 14 electric current is made to flow through the bars of the the flat bar grating under the top flight to heat it up and to cause transfer of heat to the belt and to the bitumen and minerals on this belt in the recovery zone. A plan view of a section of grating, using this method, is shown in Figure 13 and an end view of the same section is shown in Figure 14. In this illustration the bars are perpendicular to the direction (9) of belt movement and the individual bars ~46) are electri~ally insulated (61) from the beams (62) that support this grating. Each of the bars (46) is supplied with electric current from a cable (58, ~9 ' '~

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59). These bars act as slectrical resistors in series for carrying electrical current and become heated by the flow of this current. The resistance of a 6 meter long, 2.5 cm. by 0.6 cm. carbon steel flat bar is approximately 0.004 ohms and at a current of 1000 amps requires a voltage of about 4 volts. When connected in series with electrical cable (59), ten such bars (46) require approximately 40 volts and generate a heat equivalent of approximately 40 kilowatts. Banks of such bars may be placed in parallel or in series to form a large area for heat transfer and belt support.
The heat from these bars (46) is conducted to the top flight (3) and and causes bitumen (37) and minerals to slough off the belt (3). Higher voltages may be used with stainless steel bars or ni-resist bars (46) since they have a higher internal resistance than carbon steel bars (46).
In addition to, or instead of heated pipes or heated grating, the idler roller (4) of Figures 1, 2 and 12 may be heated as w~ll by providing it with a rotary seal that allows steam to flow into the inside of the roller (4) where it condenses, and to allow condensate to leave the roller through the same rotary seal or through a second rotary seal.
Eddy current may be used as well to heat the belt or to heat the environment around the belt in the recovery zone. This is illustrated in Figures 15 to 18. In Figure 15 (end view) and in Figure 16 (side view) electromagnetic coils are mounted above or below the belt in the recovery zone. The most suitable belt for this purpose is the wire spiral belt of Figure 6.
During the construction of such a belt, sequential spirals are joined by cross rods pushed through the intertwined spirals, and the ends of each cross rod (27) are joined to the ends of each individual spiral (31), as is illustrated for one spiral in Figure 15.

Therefore, each spiral is a wire coil with ends that are shorted electrically. It represents an electrical coil that can be heated conveniently by induction heating. Alternating current is supplied to the primary coils (~3) mounted above or below the endless belt in the separation zone and a core ~64) material is or may be used to concentrate the magnetic flux generated by the primary coil and cause it to pass through spirals (31) of the endless belt, which thus become secondary coils of an induction heating circuit as they pass by the primary coils (63~ when the belt moves. These spirals (31) and cross rods (27) thus represent electrically shorted coils, ~hich heat rapidly when they pass by the alternating magnetic flux of the primary coils. In other words, alternating current is induced in each steel spiral, and its interconnecting steel cross rod, moving through the recovery æone, and this current causes them to heat up rapidly. As is illustrated in Figure 16, the primary coils and their cores may straddle a large number of belt spirals and may cause heating of a large number of belt spirals as they pass through the recovery zone.
Furthermore, a large number of coils may be mounted in the recovery zone to provide induction heating to a large portion of the top flight. The frequency, voltage and amperage of alternating current supplied to the primary coils may be adjusted to achieve the desired heating of the spirals by induction and sloughing off of bitumen and minerals from the thus heated belt.
Direct induction heating of the top flight of the belt in this manner results in low energy requirements and very effective sloughing off of bitumen and minerals from the top flight in the recovery zone. The actual belt surfaces are the source of the heat and these belt surface create localized heating of the , ."~ , ~j , , .

~ 3,~
bitumen and minerals directly adjacent to the belt surfaces. Similar to a hot knife in butter, the heated belt surfaces cause bitumen immediately adjacent to the belt surfaces to heat up, become more fluid, and loose some of their adhesion to the belt surfaces. This localized heating causes rapid release of bitumen from the belt surfaces, and also causes release of bitumen and minerals from the apertures without the need to actually heat the bulk of the bitumen and minerals in the apertures. As a result, the bitumen sloughs off the belt with low energy requirements, and the average temperature of the bitumen product may be lower than with other types of heat transfer to remove bitumen from the belt in the recovery zone.
An alternate method of induction heating the belt is shown in Figures 17 and 18. This illustration is drawn on a much smaller scale than Figures 13 to 16, and shows a set of induction ovens through which the belt passes sequentially in the recovery zone. Figure 18 is a sectional end view through section line A A of Figure 17 and Figure 17 is a sectional side view through section line B B of Figure 18. The oven inside volume (67), through which the belt (3) passes, is surrounded by a steel or alloy metal enclosure (66).
~- This enclosure is the secondary coil of an induction circuit, in which the primary coil (63) is made up of insulated and heat resistant wires (65) wrapped around the enclosure. These wires are attached to power cables (58) that supply alternating current to the primary coil (63) to induce a current in the walls of the enclosure (66) These enclosure walls represents a single coil that is shorted electrically~ Alternating current in the primary coil (63) causes the enclosure (66) to heat up, and this causes the belt and the bitumen and minerals on it to heat up by conduction, radiation and convection. Only the belt and its ~ ,", , ~. ",, ,, , ~, , : :, : . . .

~3~31 :~

associated bitumen and minerals pass through the enclosure of Figures 17 and 18. Therefore, this enclosure preferably is made in the form of a narrow slit to provide close proximity between the belt and the internal walls of the enclosure for more effective heat transfer. Several such enclosures may be mounted sequentially in the recovery zone, as illustrated in Figure 17. The space between sequential oven enclosures (66) permits sloughing off of bitumen from the belt after it leaves one enclosure and before it enters the next enclosure for additional heating and for additional bitumen removal.
As described above, the invention is applied preferably to the recovery of bitumen and minerals from a mixture that is pumped to the apparatus of the invention. However, in Figure 11 the apparatus of the invention is mounted on a barge floating on a tailings pond to collect bitumen and bitumen wetted minerals from the mixture of the tailings pond without necessarily pumping that mixture, and without necessarily enclosing the separation zone of the separator in a tank.
Mined oil sands plants using current commercial technology are characterized by huge tailings ponds, in which the tailings of the plant are pumped to settle the fine minerals of the tailings and to produce clear water for recycle to the plant. Illustrated in Figure 11 is a typical mined oil sands tailings pond surrounded by dykes (47) that enclose the water (49) and sludge (51 ? layers of that pond. As in most such drawings of a tailings pond, the vertical dimensions of Figure 11 are exaggerated with respect to its horizontal dimensions. The pond contains water, minerals and bitumen that are settling, resulting in clear water at the top of the pond and a progressively denser sludge mixture of minerals and water from top to bottom of the pond. Coarse minerals (54) have settled to the bottom of the pond and settling layers of sludge (51) of clay, bitumen and water, occupy a large portion of the pond volume. Bitumen is present in the pond in two forms, in the form of droplets of bitumen dispersed throughout the sludge, and in the form of bitumen mats that float within the pond volume at various levels.
Some of the bitumen mats (52) at times float on top of the pond, while other mats of bitumen (53) have accumulated at various other levels in the sludge.
In the embodiment of the invention illustrated in Figure 11 the apertured oleophilic belt is mounted on a barge (56) floating in the pond. At least two belt supports (4 and 5) are mounted on the barge to provide an approximately horizontal top flight (3), above the hold (7) of the barge that serves as the receiver for bitumen (35) falling from the top flight. A bottom flight (2) hangs down from the barge and under the barge into the mixture of the pond. One of the belt - 20 supports is a drive roller (5), with sprockets or pins, that continuously revolves the belt, and causes the -- bottom flight (2) to collect mats of bitumen (52 and 53) from the pond layers through which it travels as ~ the barge moves through the pond. These bitumen mats -~ are shown as the dark clouds floating in the pond of Figure 11. In operation the bottom flight (2) of the belt comes in contact with these bitumen mats, while water and sludge pass by the belt and through its apertures. These bitumen mats adhere to the belt upon contact and are conveyed upward through the pond by the belt, along the side of the pond barge (56) and to the top flight (3). There the bitumen falls off the belt into the hold (7) of the barge (56) by gravity, or with the help of jets of fluid or heat as described previously. In this manner a large amount of bitumen can be collected from a mined oil sands plant without `

the necessity of pumping the sludge of that pond to a separation plant.
If desired, sludge without bitumen mats may be pumped from out of the inside of the bottom flight (2) catenary of Figure 11 for further processing elcewhere to recover the dispersed bitumen droplets from that sludge. This may be achieved when a front and rear wall (not shown) are provided adjacent t~ the bottom flight (2) to assure that the sludge entering the catenary inside must pass through the belt apertures, and to prevent bitumen mats from entering the inside of the catenary. In this manner, the bitumen mats are collected by the barge and all the sludge that is pumped from the barge is free of bitumen mats, resulting in lower and more predictable sludge pipeline pressure drops. Tailings pond sludge has a viscosity that is 2 to 10 times as high as water and, as a result, when these tailings are pumped through a pipeline, the pressure gradient is higher than if water were pumped through that pipeline. However, cold bitumen is several orders of magnitude more viscous than sludge. Therefore severe pump damage or malfunctioning may result when bitumen mats enter a sludge pipeline, fill the whole pipe cross section, and cause a dramatic increase in pressure gradient. Using a pump inlet as illustrated in Figure 11, but provided with front and rear walls, to collect and screen out bitumen mats, therefore will be beneficial for pumping tailings pond sludge. When used for that purpose the barge will likely remain at one place on the pond or only move to various parts of the pond as required to reach all the sludge as the pond is pumped empty of sludge.
In addition to a front and a rear wall, a horizontal wall may be installed in the catenary of the embodiment of Figure 11. This wall should be some "~,,, : . : , :

.

distance below the interface (50) between the sludge and the water in the tailings pond, and the pump inlet mounted below this wall to make sure that only sludge is pumped out of the pond, and not water.
Cold, high viscosity bitumen may be removed from the hold (7) of the barge (56) of Figure 11 with a bitumen conveyor, a device illustrated in Figures 19 to 22. This device, to my knowledge, is a new device not previously disclosed in the prior art. As shown in Figure 19, it comprises a roller chain ( 70) supported by a driven sprocket (71) mounted on one end of a long bar (72) pipe or tube, and a stationary chain guide, revolving idler pulley (73) or idler sprocket, mounted on the other end of the long bar (72) pipe or tube.
The driven sprocket is revolved by a motor (74) through a gear box (not shown) to cause movement of the roller chain (70) in the direction (75) shown. Attached to the bar (72), near the driven sprccket (71) is a deflecting pipe (76) provided with a restricted passage, hole or orifice (77) through which the chain can pass. The bottom end of this device is placed in the hold (7) of the barge (56) of Figure 11 to convey bitumen from this hold upward into a receptacle for transport. It may also be used to convey bitumen from the tank (78) of Figure 19. (or from the hold (7) of Figure 11) This tank contains a bottom layer (79) of bitumen product covered with an upper layer (80) of water or sludge. Initially the chain (70) is clean and dry and no oil is present on the surfaces of the roller linkages (81). When the device is inserted into the tank (78) its bottom portion, including the chain guide or idler (73) and a portion of the chain (70) become covered with bitumen which adheres to the chain because the chain is oleophilic. The motor (74) is started and this results in movement of the chain in the direction (75) shown, which drags bitumen from the bottom layer ~ ~ o~ 3~
(79) of the tank (78) upward along the bar (72) until it reaches the restricting orifice (77) adjacent to the sprocket and the deflecting pipe. Only a small amount of water or sludge from the top layer (80) of the tank (78) is carried upward along with the bitumen on the chain. This water or sludge is much less viscous than the bitumen of the bottom layer (79) and hence is not carried upward by the chain (70) as effectively as bitumen. The deflecting pipe (76) and the restriction or orifice (77) in this pipe is shown in more detail in Figure 20. This deflecting pipe allows the sprocket and the chain to pass through the restriction (77) but most of the bitumen that is carried upward by the chain is not permitted to pass through this orifice but flows upward and away from the chain (70) and sprocket (71J
through the deflecting pipe. Bitumen (not shown) that under normal operation flows from the end of the deflecting pipe then flows into a chute (not shown) or into another container for transport or removal.
During operation, because of gravity, there is a flow of bitumen downward along the chain relative to the chain surfaces. ~owever this is readily overcome by making sure that the upward velocity of the chain is greater than the average downward velocity of the bitumen relative to the chain surfaces. The effect of gravity also serves to minimize the upward movement of water or sludge from the top layers of the tank with the moving chain. Since bitumen has a viscosity that is several orders of magnitude higher than water or sludge, the downward velocity of bitumen relative to the chain surfaces is much lower that the downward velocity of water or sludge relative to the chain surfaces. As a result, during operation, much more bitumen is removed from the tank (78) bottom layers than free water or sludge from the tank top layers.

~ , ' , ~ ,~ , ;' ' ' ' ' .
- , .: ,: ' . . ' -~

, The device therefore serves to convey mainly bitumen, and to leave water and sludge behind.
The chain (70) of Figure 13 is not enclosed except for a short enclosure (82) which may be used to minimize contact between the chain surfaces (83) returning to the tank (78) and the upper layers (80) of water or sludge. The decending chain therefore does not come in contact with the upper layers (80) of sludge or water and this enhances the accumulation of bitumen in the chain as it passes through the bottom layers (81) of bitumen. However, in certain cases it is advantageous to also enclose the rising flight (83) in a pipe or channel, or to enclose both the rising flight and the decending flight (84) of the chain ~70), for example, when the bitumen conveyor is mounted on an incline. When the bitumen conveyor is mounted on an incline, or when it is mounted horizontally, there is a tendency for bitumen to fall from the chain after it has left the tank (78) unless it is contained in close proximity to the chain (70). A short section of the enclo~ed chain (70 or 83) is shown in sectional side view along the enclosure (85) in Figure 21, showing the chain (83) and showing the approximate flow profile (86) of bitumen in the enclosure (85) due to the upward movement of the chain through the stationary enclosure, and due to the downward force of gravity on the thus contained bitumen.
A sectional view of the enclosure (85) and chain (83) across the enclosure is shown in Figure 22.
Illustrated in this Figure is a cylindrical enclosure, such as a pipe. However the enclosure may also take the form of a square or rectangular tube.
While Figures 19 to 22 illustrate the use of a roller chain for use as the bitumen conveyor, any other type of chain may be used for that purpose, as long as it can be driven. For example, conventional link ,, .:

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chains may also be used, in which case a link chain pulley is used for the drive pulley. Belts may also be used instead of chains to convey bitumen out of containers. In pilot plant tests a standard but long vee belt was used effectively to remove bitumen from barrels containing water and bitumen. This belt was mounted between two pulleys on a steel bar. One of these pulleys was driven by a gear motor and the other was immersed in a barrel of bitumen and water for removal of the bitumen. Some of the water of the barrel was carried upward and out with the bitumen, but most of the free water remained behind in the barrel while essentially all the bitumen was removed from the barrel.
!

Thus, the present invention uses an endless belt supported by at least one driven conveyor shaft and at least one other belt support guide to form a generally horizontal top flight and a bottom flight that hangs down from the belt supports in the form of an inverted arch or catenary. The bottom flight forms part of the separation zone and is partly immersed in the mixture it is separating. The top flight forms part of the recovery zone and is usually at a higher temperature than the mixture separating in the separation zone.
In the separation zone, water and water wetted minerals flow through the belt apertures while bitumen and bitumen wetted minerals are captured by the revolving belt surfaces. During separation, the mixture is introduced slowly and uniformly to the bottom belt flight and bitumen and bitumen wetted minerals, captured by the belt surfaces, are conveyed to the top flight where they are removed form the belt and collect in a receiver under the top flight. Before reaching the top flight this bitumen and mineral may be sprayed with a mist or fog of water to wash off , ~

~ r J ~ ~, 3 ~ ~

hydrophilic minerals, that flow back into the separation zone as the bitumen and bitumen wetted minerals are conveyed into the recovery zone. Mixture may be introduced into the inside of the immersed belt catenary for separation and withdrawn from the outside of the catenary after removal of bitumen and bitumen wetted minerals from the mixture as it passed through the belt apertures. Alternately the bottom belt flight may be immersed in the mixture to be separated and mixture may be withdrawn from the inside of the catenary after removal of bitumen and bitumen wetted minerals from the mixture and after it has passed through the belt apertures. In both cases, the mixture has an opportunity to distribute itself over the immersed surface of the belt and slowly and uniformly flow to the belt and through the apertures.
The difference between these two cases is the direction of flow through the belt. Finally,when the invention is used for recovering bitumen mats from a tailings pond, there may not be a net flow of mixture into or out of the catenary inside, even though there will be some flow of mixture through the apertures as bitumen mats are captured by the belt and in the apertures.
The speed of the belt may be adjusted for optimum capture of bitumen and bitumen wetted minerals by the belt surfaces and optimum flow of water and water wetted minerals through the apertures of the belt.
When the belt moves too slowly there is potential for closing too many of the apertures with bitumen and bitumen wetted minerals. This may cause water and water wetted minerals to flow faster than desirable through the remaining apertures, or it may reduce the total flow through all the remaining apertures below desirable limits. When the belt moves too fast, it may not give bitumen and bitumen wetted minerals enough time to adhere to the belt surfaces or it may waste : .

-~ ~ 31~
mechanical energy by conveying less than the desired thickness of bitumen into the recovery zone. All this is governed to a large degree by the concentration of bitumen and bitumen wetted minerals in the separating mixture. Generally, the lower the concentration of bitumen in the mixture, the lower the belt speed. The larger the concentration of bitumen in the mixture, the faster the belt speed or the greater the width of belt used for the separation. The thickness of bitumen on the rising belt is an indication of process performance and it iæ within the competence of a person skilled in the art to vary the belt speed to achieve maximum separation efficiency.
The size of the bitumen particles recovered may be controlled to some degree by the size of the apertures of the belt. When mainly bitumen mats are to be recovered from tailings pond sludge, the apertures selected may exceed 3 or 4 ceDtimeters in width and length, and in that case not much dispersed bitumen is recovered from the pond. On the other hand, when finely dispersed bitumen is to be collected from a mixture, the size of the apertures of the belt may be reduced to as low as a quarter of a centimeter in width and in length, depending to some degree upon the overall performance desired. However, when the bitumen particles in a mixture are small, agglomeration of these bitumen particles into larger bitumen particles before separation may be desirable instead of using small belt apertures for the separation. Various agglomeration procedures are discussed in Canadian patents 1,144,498 granted to me on 12 April 1983, 1,167,792 granted to me on 22 May 1984, 1,243,984 granted to me on 1 November 1988, and in patent application Serial No. 604,527.
Agglomeration of bitumen in an aqueous mixture is achieved by providing mechanical oleophilic surfaces s,,!, ; ., ~

3 ~

that tumble with or pass through the mixture. During agglomeration, the bitumen particles of the mixture come in contact with these mechanical oleophilic surfaces, adhere to them, and accumulate on them until ' they form a thick layer that eventually sloughs of these surfaces, back into the mixture, in the form of enlarged bitumen particles. As a result of this agglomeration procedure, the bitumen particles after j contacting the mechanical oleophilic surfaces are ¦ 10 larger in size than the bitumen particles prior to such contacting. Revolving drums are preferably used for agglomexating bitumen in an aqueous mixture. The mechanical oleophilic surfaces may either be oleophilic free bodies that tumble with the mixture in the drum, or may be oleophilic column packings or oleophilic ropes that revolve in fixed relationship with the drum interior and pass through the mixture as the drum revolves.
In the present invention, conditions in the separation zone and in the recovery zone differ from the prior art. The belt flights differ in shape. The temperature in the separation zone may be lower and, the mixture may be more evenly distributed over the total belt area. The flow of mixture to the belt and through the belt apertures may be kept lower and more uniform so as to increase adhesion of bitumen and bitumen wetted minerals to the belt surfaces. In addition, a larger portion of endless belt may be immersed in the separating mixture so as to increase adhesion of bitumen and bitumen wetted minerals and to minimize any detachment of bitumen and minerals from the belt after they have become attached. Furthermore, the unimmersed portions of the bottom flight of the ~resent invention are those ~ortiorl of the inverted arch or catenary that are at a slope so close to vertical that bitumen is more likely to be carried into 3 ~ ~

the recovery zone than to fall off the belt in the separation zone.
In the recovery zone, unlike in the prior art, no portion of the belt top flight is immersed, but it moves approximately horizontally, instead of being inclined, thereby increasing the effect of gravity on the bitumen and minerals on the top flight to cause sloughing off of bitumen from the belt. Friction and bitumen adhesion for bitumen may be used to drag bitumen from the belt and out of the apertures. The temperature in the recovery zone may be increased independently of the separation zone to reduce the bitumen viscosity and increase the flow of bitumen and minerals from the belt. Jets of fluid may be used to reduce the bitumen viscosity and/or to blow the bitumen orf the belt in the recovery zone. Electric power, through resistance and/or through induction may be used as an alternate method to remove bitumen from the top flight. Application of those many conditions, new concepts, and combinations, described above were not disclosed in the prior art of Canadian Patent No.
1,129,363. Transfer rollers were required in the prior art, which are not required in the present invention, resulting in a simpler and more effective system that can make better use of flexible metal process belts that are thicker and that can collect and carry more bitumen and bitumen wetted minerals per unit area of belt than the belts of the prior art.

3 ~ ~

Sludge from the tailings pond of a mined oil sands plant at 5 degrees ~. , containing 5~ bitumen, 70 water and 25% solids composed mainly of clay, is provided by a pump, submerged 15 meters below the surface of that pond, to a separator of the present invention as illustrated in Figure 2. Two hundred cubic meters of sludge per hour are pumped into the in~ide of the catenary of the bottom flight of a process belt consisting of a multitude of high carbon flat strips of steel, 1.3 cm. wide and 0.16 cm. thick, formed in the shape of a square wave with sloping sides and joined with 0.5 cm. diameter high carbon cross rods. The cross rods pass through holes in the flat metal strips and join sequential strips, as is illustrated in Figure 5, into an endless belt. The cross rods are spaced 2.5 cm. apart and the sides of the square wave are on average 1 cm. apart, resulting in apertures that are approximately 1.2 cm. high, 0.6 cm wide and 1.5 cm. long when the belt is partly coated with bitumen and minerals. The endless belt is supported with an 32 cm. diameter idler roller made from standard pipe and with a 10 cm. shaft with 30 cm.
sprockets that mesh with the cross rods of the belt and drive the belt. The belt is 5 meters wide and 15 meters long, is totally enclosed in a metal tank with cover, and the bottom flight is immersed up to 1 meter below the top flight.
Sludge passes through the bottom flight from inside to outside of the catenary, and bitumen and bitumen wetted minerals are captured by the bottom flight surfaces while water and water wetted minerals of the sludge pass through the bottom flight apertures and are pumped from the separator enclosure through a bottom outlet. ~he sludge that has passed through the ,, " ", 5 ' ' ' '" !' " ' ' ' ~ ; ~ ' , separator is pumped to disposal to a new holding pond in a mined out portion of the mined oil sands site.
The bitumen and bitumen wetted minerals, captured by the bottom flight, are conveyed by the belt to the top flight that is dragged horizontally over 5 meter width and 5 meter length of grating, made from upright flat bars mounted diagonally under the top flight. Jets of low pressure steam blow down onto the top flight and assist in stripping bitumen and bitumen wetted minerals from the top flight and depositing it as a product at 40 degrees C. into a receiver under the top flight.
This receiver is double walled and insulated, and is partly immersed in the separating mixture in order to allow immersion of the bottom flight to within 1 meter of the top flight and to have sloping sides on the receiver that are steep enough that product can readily be pumped away without minerals accumulating in the receiver. The belt moves at 15 cm. per second and 28 cubic meters per hour of product, consisting of 10%
mineral, 30% bitumen and 60% water are deposited into the receiver.
A second separator, using the same type and dimensions of belt is used to remove water and some remaining water wetted minerals from the product of this first separator. However, the recovery zone of this second separator uses heated pipes, as illustrated in Figure 12. The belt speed of the second separator is about half that of the first separator. Product from the first separator is pumped into the inside of the catenary of the second separator and passes to the belt where bitumen and bitumen wetted minerals are captured by the belt. Water and remaining water wetted minerals pass through the apertures and are removed from the bottom of the second separator by a pump.
These are discarded to the top of the first tailings pond at a rate that maintains a liguid level in the ~ ~33~ 3~
second separator 1 meter below the top flight. Bitumen and bitumen wetted mineral is conveyed by the belt to the top flight where the heat from pipes containing condensing high pressure steam under the top flight causes bitumen product to flow from the top flight into the receiver under the top flight. A fan circulates warm air through the belt near the end of the top flight, near the sprockets, and blows some more bitumen and bitumen wetted minerals from the top flight, and into the receiver, before the belt surfaces pass the drive sprockets and return to the separation zone. A
thin coating of bitumen remains attached to these belt surfaces returning to the separation zone. The final bitumen product from the second separator consists of approximately 12 cubic meters of product per hour containing 65% bitumen, 10% minerals and 25% water and has a temperature of 55 degrees C.
The product from the second separator is pumped out of the receiver and thereafter is blended with an equal amount of naphtha, is heated to 95 degrees C. and is spun first in a scroll centrifuge to remove coarse minerals and then in a bowl centrifuge to remove additional minerals. The coarse minerals of the scroll centrifuge contain some carbon, are rich in metallic minerals of titanium and zirconium, that are coated with bitumen and naphtha, and contain most of the water of the bitumen product. They are hereafter introduced into the top of a fluidized reactor and air is introduce at the bottom of that reactor, which is ignited to flash off the naphtha and water, and burn off the residual bitumen and carbon. The resulting minerals are suitable for a reaction with hot chlorine gas to produce titanium and zirconium chloride that is thereafter separated by distillation to form the raw materials for the production of titanium and zirconium`
or their oxides. The bitumen and naphtha overflow frGm ~ ' ' ' ~ ' : :~
. ., ~

3 ~ ~

the centrifuges is fractionated to remove the naphtha for reuse as blending feed for the centrifuges, and the bitumen is coked and upgraded to synthetic crude oil.
In this example, bitumen product from the first separator was processed in a second separator to remove water and minerals and produce a bitumen product of higher quality. The process of the present invention may also be used to process bitumen products from other processes, such as from flotation processes or from hot water processes, to reduce water and minerals content and yield a bitumen product of higher quality.

Two hundred cubic meters per hour of extraction tailings from a mined oil sands plant, containing 0.5%
bitumen, 50% sand, silt and cla~ and 49.5% water are separated by the same two separators of Example 1. The major difference is that instead of the feed being at 5 degrees C., the tailings that are to be separated come from the mined oil saDds plant at 50 degrees c. Belt speed is adjusted visually by the operator by observing the belt portions that emerge from the mixture. The belt speed, which for this low concentration of bitumen in the feed at sludge temperature would have been set a 2 cm. per second, is now set at 6 cm. per second so that the captured bitumen, which has a lower viscosity than the bitumen captured from sludge in Example 1, does not fall off or flow down the unimmersed portion of the catenary back into the separation zone. The bitumen product flowing from the second separator at 1.3 cubic meters per hour contains 55~ bitumen, 20%
minerals and 25 % water. When diluted with naphtha and spun, most of the minerals from this product end up as underflow in the scroll centrifuges.

3 ~ ~

A similar fluidized bed is used as in Example 1 to clean up the minerals product which contains 20%
rutile, a high grade titanium ore. After fluidized bed removal of naphtha, bitumen and water, this rutile is separated from other minerals present in the minerals product by magnetic and high tension mineralogical separation procedures and then is chloxinated in a hot reactor to produce titanium tetrachloride and then titanium dioxide, which is a white paint pigment that has wide application in the coatings industry. The naphtha and bitumen overflow from the centrifuges is treated as in Example 1 to produce naphtha recycle for the centrifuges and bitumen for coking and upgrading to synthetic crude oil.

One hundred cubic meters per hour of oil sands from a surface mine are mixed with 150 cubic meters of water per hour at 50 degrees C. for 10 minutes in a conditioning drum to digest the lumps of oil sand and to disperse the bitumen and minerals in water. The resulting slurry at about 40 degrees C. is passed over a vibrating screen and streams of water from nozzles add an additional 100 cubic meters of water per hour to blow the slurry through the screen. Rocks, debris and undigested lumps of clay and oil sand are discarded while the slurry is pumped to the inside of the catenary of a separator of the present invention resembling Figure 1 but totally enclosed with a tank and covqr, and with front and back sides that close off the catenary and prevent flow of slurry past the belt edgeQ .
The endless belt of the separator is a spiral wound belt similar in construction to the illustration in Figure 6. The spirals and cross rods are made from . ' " '~ ' ~ . : ,, . ,,: . . ~ , , - ' -, ' ~ ~":

~ 3 ~

0.15 cm diameter high carbon steel wire and the spirals are wound to give a 1 cm. thick belt with approximately triangular apertures that are on average 2 square cm.
in cross section and approximately 1.2 cm. in length when the belt is partly coated with bitumen and i minerals. A friction drive, similar to Figure 4C is used to support and drive the belt. Insulated flat bar grating mounted diagonally under the top flight is used to support the top flight and induction coils are ¦ 10 mounted above the the top flight and are supplied with alternating current to cause eddy current heating of the spirals and cross rods of the belt as illustrated in Figures 15 and 16. Warm air is circulated through the belt similar to the illustration in Figure 12 to blow additional bitumen from the belt before the belt surfaces return to the separation zone.
The bottom flight of the belt is immersed in the slurry it is separating up to about 1 meter below the top flight, and a double walled insulated receiver under the top flight, to collect the bitumen product, is partly immersed in the slurry as well. The belt immersion level is controlled by the rate o~ withdrawal of processed slurry from the bottom of the tank surrounding the bottom flight. This tank has steep sides with the bottom forming a steep inverted pyramid to prevent sand of the slurry from accumulating in this tank. The processed slurry, now called tailings, is pumped away from the separator to a disposal site where warm water is removed from these tailings and returned to the conditioning drum while the de-watered but still wet tailings are deposited. Run off water from these de-watered tailings is allowed to settle to remove suspended solids and is returned to the separation process.
Bitumen and bitumen wetted minerals are captured by the belt surfaces as the slurry passes through the ~- ' ~ :' :

belt apertures and are conveyed to the top flight. A
bank of nozzles blows a mist of cold water onto the bottom flight æurfaces as they emerges out of the slurry and before they reach the top flight. Water wetted minerals on the bitumen conveyed by this belt are diluted by this mist of water and flow down the belt incline back into the separation zone while the thus washed bitumen and bitumen wetted minerals continue on to the top flight where the bitumen and bitumen wetted minerals are removed as explained above and collect in the receiver below the top flight. The thus produced bitumen product is diluted with naphtha and spun in centrifuges similar to Example 1 and the minerals from the centrifuges are either discarded with the tailings or are processed to recover the titanium and zirconium ore as in Example 1.

A mined oil sands plant mines 100,000 tonnes of oil sand ore per day and uses a hot water process to extract bitumen f~om the ore, and coking and refining to produce 50,000 barrels of synthetic crude oil per day from the extracted bitumen. Bitumen recovery from the ore is 90% and 10% of the bitumen originally present in the ore is discarded from the plant via the oversize reject, the extraction tailings and the centrifugal tailings. A naphtha recovery unit is used to recover naphtha from the centrifugal tailings. The total amount of bitumen discarded from the plant is 5,600 barrels per day. Of`this, 1,200 barrels per day are discarded with the oversize and the remaining 4,400 barrels per day are discarded with the tailings. A
tailings pond with a surface area of 3 kilometers by 2 kilometers is located near the plant, formed from a shallow natural depression in the landscape, surrounded ,, ,. - ' "
: :
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by dykes of tailings sand. Tailings from the plant are pumped to this tailings pond where the tailings are beached. Sand settles and accumulates on the beach of the pond and is used as the building material for increasing the length and height of the dykes around the pond. About half of the silt and clay of the tailings and about a quarter of the bitumen and water of the tailings are trapped by the sand grains on the beach, and the rest flows into the pool of the pond where the clay, bitumen and water gradually settle into a sludge layer with a clear water layer on top. After 7 years of plant operation, the upper layers of the pond have settled sufficiently and the upper layers of water clariied sufficiently that water can be taken from the top of the pond for reuse in the plant. Prior to this time, about 100,000 tonnes of fresh water per day were pumped from a river adjacent to the plant for use in the extraction process~ After that, the fresh water requirements reduced considerably as pond recycle water replaced a large portion of the fresh water requirements.
Sludge accumulating in the pool of the poDd settled rapidly to 20% solids content and then slowly, over the years, compacted to about 35% solids content near the bottom of the ~ond, while the middle layers represented a dynamic settling regime representing clear water near the top and compacted sludge near the bottom. Specific gravity of these layers was 1.0 near the top of the pond and increased progressively deeper in the pond as the sludge settled and its solids content;increased. Bitumen dispersed in the tailings, flowing into the pond, became part of the sludge layers. At times some of it was light enough that it flcated on top of the pond and formed bitumen mats that remained there for some time until they cooled and de-aerated enough to become denser than water. Then they sank and found a level in the pond where they were neutrally buoyant, but were subject to silt and clay settling from above and pushing them deeper into the pond. Minerals present in association with the bitumen of the tailings in varying percentages resulted in bitumen particles that varied considerably in density, and each settled in the pond to reach neutral buoyancy and were subject to a dynamic patterns of silt, clay and bitumen settling within the pond. Some bitumen particles coming in contact with each other during the settling pr~cess joined and formed bitumen mats within the settling sludge layers. All this resulted in a tailings pond that contained a settling sludge with varying clay and water contents interspersed with bitumen particles and bitumen mats. Bitumen content within the pond varied with location, with depth and with time.
After 20 years of such plant and pond operation, about 25 million barrels of bitumen has accumulated in the tailings pond. An apertured oleophilic endless belt is mounted on rollers on a pond barge to make a separator to collect the bitumen mats that are known to be floating in the tailings pond within the sludge layers. The endless belt is fabricated from two Number 240 roller chains that have extended pins on one side of the chain. A Number 240 roller chain is made up of chain links that have a 3 inch pitch and uses rollers that are 1.875 inch in width and 1.875 inch in diameter. A spiral mesh screen is mounted between these two roller chains to form a 200 inch (5.08 meter) wide endless belt with a roller chain on each edge. The roller ohains each have a 3 inch pitch, resulting in a spacing of 7.6 centimeters between sequential roller pins. Cross rods, equal in diameter and strength to the roller chain pins, and 5.08 meter in length each, are used to join the two roller chains at their pins 3~
with tubular couplings. High carbon steel wire spirals are mounted over the cross rods in a manner similar to Figure 6 to form a flexible continuous belt that is 100 meters long before it is joined at the ends to form an endless belt. This belt has a cross rod spacing of 7.6 centimeter and the spacing between sequential wire loops of each spiral on the cross rods is 8 centimeters. The resulting endless belt is a very coarse steel wire structure that is very flexible and that has a roller chain securely attached to each edge of the belt. The belt is placed over two rollers on the barge as illustrated in Figure ll. These rollers each consist of a shaft with a conveyor roller, that is 5 meters long, and with two roller chain sprockets mounted on the shaft, one at each end of the conveyor roller, to mesh with the roller chains on the edges of the endless belt. The roller chains at the edges of the belt and the sprockets on the shafts serve to keep the belt in tension, in alignment, and to drive the belt. The shafts are mounted on bearings; one set of bearings on each side of the 8 meter wide barge barge, and are coupled to hydraulic motors that revolve the shafts.
A cover is placed over the belt assembly to isolate it from the environment, and a bitumen receiver (7) is mounted in the hold of the barge (56) to collect bitumen falling from the top flight ~3) of the belt.
The top flight of the belt is not supported by grating but is kept in tension between the two rollers (4 and 5) under control of the hydraulic drives. The drive roller (5) revolves the endless belt at lO centimeters per second and the idler roller (4), also connected to a hydraulic motor, controls the tension in the top flight and assists the drive roller to control and drive the endless belt. A boiler on the pond barge provides high pressure (lO0 psi) steam that is piped to 3 ~ ~
a bank of nozzles across the width of the endless belt at the mid point between the two shafts. These nozzles serve to blow bitumen from the top flight into the hold of the barge. Bitumen falls off the belt before it reaches the nozzles and also after it has passed the nozzles and the steam flow to the nozzles is controlled to blow enough bitumen from the belt to open the belt apertures before these return to the bottom flight and enter the pond surface.
The endless belt bottom flight hangs down from the two conveyor rollers in the form of a catenary under the barge and in the sludge layers of the pond and comes in contact with bitumen droplets and bitumen mats as the belt revolves and the barge moves through the pond. Sludge, water and bitumen droplets pass through the belt apertures, as the belt moves and as the barge moves on the pond, and bitumen droplets and bitumen mats adhere to the belt surfaces as these come in contact. The adhering bitumen is conveyed through the sludge layers of the pond, passes through the clear water layer at the top of the pond and then passes by the idler roller (4) to reach the top flight of the belt where it falls off the belt with and without the assistance of high pressure steam from the no~zles above the belt.
Water from the top of the pond is pumped under pressure to banks of nozzles mounted along both sides the rising belt to provide a fine mist of water to wash sludge from the bitumen that emerges with the belt surfaces out of the pond. The wash water and sludge running down the emerging belt, return to the pond for subsequent mixing and settling within the pond.
The belt speed is kept low so that the compacting sludge layers of the pond are disturbed as little as possible by the moving belt. However hydraulic speed control is provided to the roller drives, so that the r ~

~ ).;3~
-belt speed can be adjusted or .increased when it is noticed that bitumen is flowing down the belt surfaces that emerge from the pond. Observation windows are mounted in the belt cover near both sides of the barge, so that the emerging belt can be observed by the operators for controlling the belt speed, and also so that the belt surfaces returning to the pond can be observed by the operators for controlling the steam nozzles.
A bitumen conveyor, as illustrated in Figure 19 is permanently mounted in the hold (7) of the barge at a slope of 45 degrees. This bitumen conveyor is provided with a pipe enclosure around the roller chain, as illustrated in Figures 21 and 22, and is used to convey bitumen from the hold of the barge to a transport barge that conveys the bitumen to the shore of the pond, where it is diluted with naphtha, centrifuged and pumped to the mined oil sands plant for upgrading to synthetic crude oil. A centrifugal sum pump, with a floating pump suction inlet is used to pump water and sludge from the hold of the barge, left behind by the bitumen conveyor and accumulating on top of the bitumen in the barge, back into the pond to keep the barge floating.
This very simple device is thus used to scavenge bitumen mats from the tailings pond and to incxease synthetic crude oil production of the mined oil sands plant.

For this examp.le the same pond and the same barge is used for recovering bitumen mats as in Example 4.
However, in stead of using an endless belt made from spiral wound wires with a roller chain on both edges, the belt of Example 5 consists of two roller chains ' . : , , ~, ~' , ~,,, ~L ~ 3 ~
with roller chain pins e~tended at one edge of each chain. The roller chains are placed in parallel such that the protruding roller pins face each other, and 5.08 meter long tubes are used to join the parallel roller chains at each roller pin. The tubes have bores slightly smaller in diameter than the protruding roller chain pins and they are attached to these pins by heat shrinking the pipe ends over the pins. The resulting endless belt consists of two roller chains, spaced approximately 5 meters apart and joined at each linkage with a cross rod or pipe. When additional strength is required, solid rods are used in stead of pipes and the ends of those rods are drilled with concentric holes suitable for heat shrinking over the roller pins of the chains. No spiral wires are mounted over these cross rods. The resulting endless belt is a coarse belt with large openings. It is suitable for capturing viscous bitumen mats from cold tailings pond sludge, but it does not capture very much dispersed bitumen from the tailings pond.
Although the invention as has been described is deemed to be that which forms the preferred embodiments ~ thereof, it is recognized that departures may be made - therefrom and still be within the scope of the invention which is not to be limited to the details disclosed but is to be accorded the full scope of the claims so as to include any and all equivalent methods and apparatus.

3 v ~

For example, roller chains may be mounted on one or both edges of the endless belt, as described in Example 4, or a suitable endless belt may be constructed from roller chains and cross rods as described in Example 5. The same may be done for the other examples, or roller chains may be added to the edges of the belts of Figures 5 or 6, to facilitate driving the belt, to maintain it in tracking alignment, and to assist in maintaining the desired belt tension.
It may also be done to improve tolerances between the belt edges and the walls of the separation zone tank of Figure 3 to reduce flow of mixture past the the belt edges and to increase flow of mixture through the apertures. Similarly, attachments may be provided to the belt edges in close proximity to these tank walls of Figure 3 to reduce the flow of mixture past the belt edges.
In addition, the top flight of the belt in the recovery zone may be conveyed over a bank of heated or unheated conveyor idler rollers, in stead of being dragged over flat bar grating. These conveyor idler rollers may be pipes or tubes with a bearing and a support at each end, or these pipes or tubes may rest on rollers that are supported by bearings. ~otary seals may be provided at the ends of these pipes to allow steam entry and condensate removal if required.
In addition, the top flight of the belt may also be dragged over a bank of stationary heated pipes in stead of, or in addition to, over grating.
Other similar minor modifications to achieve the objectives of the invention disclosure will become apparent to those skilled in the art consistent with, and not differing in any significant way from, the concepts described in these specifications and claims.

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Claims (80)

THE EMBODIMENTS OF THE INVENTION IN WHICH EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:

1. A method for the recovery of bitumen and bitumen wetted minerals from a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, which method comprises passing through the mixture an apertured endless belt whose path includes a bottom flight that passes through the mixture and a top flight that passes above the surface of the mixture, whereby bitumen and bitumen wetted minerals adhere to the bottom flight of the apertured belt as the belt passes through the mixture and emerges from the mixture, and bitumen and bitumen wetted minerals fall from the top flight of the apertured belt into a receiver located under the top flight.

2. A method as in Claim 1 wherein the apertured belt is supported by at least two supports located above the surface of the mixture in such manner that the top flight extends between the supports in a substantially horizontal path and the bottom flight extends between the supports in an inverted arch or catenary, or in a shape that approximates to an inverted arch or catenary, and wherein at least a portion of said mixture including water and water wetted minerals pass through the apertures in the bottom flight of the apertured belt.

3. A method as in Claim 2 wherein front and rear walls are provided adjacent to the edges of the endless belt along the immersed portion of the bottom flight, to cause flow of at least a portion of said mixture through the belt apertures.

4. A method as in Claim 2 or 3 wherein said mixture for separation is introduced inside said inverted arch or catenary, wherein at least a portion of said mixture flows through said apertures from the inside to the outside of said arch or catenary.

A method as in Claim 2 wherein said inverted arch or catenary is enclosed in a tank that contains said mixture for separation.

6. A method as in Claim 2 or 3 wherein liquid is withdrawn from the inside of said arch or catenary to cause flow of at least a portion of said mixture through said apertures from the outside to the inside of said arch or catenary.

7. A method as in Claim 2 wherein said endless belt is an open mesh belt comprising a large number of long and narrow flat strips of metal each formed into a shape resembling a square wave with sloping sides, said strips being at least provided with two holes near the top and two holes near the bottom of each square wave to accept metal cross rods that pass through said holes and join said strips into a flexible continuous endless belt, wherein said flat metal strips or said cross rods are made from an oleophilic metal or are coated with an oleophilic coating.

8. A method as in Claim 7 wherein said flat strips and cross rods are made from high carbon steel.

9. A method as in Claim 7 wherein said endless belt is supported by at least one stationary belt guide or revolving conveyor end roller and by at least one driven revolving shaft with sprockets that engage with cross rods of said flat wire metal belt and drive said belt.

10. A method as in Claim 2 wherein said endless belt is a spiral mesh belt comprising a large number of long spiral wound metal wires that are joined into a flexible continuous endless belt by connecting rods, each passing through pairs of meshing spirals to form a continuous belt of multiple hinges of metal wire, wherein said spiral wound wires or said cross wires are made from an oleophilic metal or are coated with an oleophilic coating.

11. A method as in Claim 10 wherein said spiral wound wires and said cross rods are made from high carbon steel.

12. A method as in Claim 10 wherein said endless belt is supported by at least one stationary belt guide or revolving conveyor end roller and by at least one driven pin roller that engages with said spiral mesh belt and drives said belt.

13. A method as in Claim 7 or 10 wherein a roller chain is attached to one or both edges of said endless belt.

14. A method as in Claim 2 wherein said endless belt is made by joining two parallel roller chains at each chain link with cross rods of which the ends attach to extended roller pins of the roller chains.

15. A method as in Claim 2 or 3 wherein said endless belt is supported by at least one stationary belt guide or revolving conveyor end roller and by at least one driven revolving conveyor end roller that drives said moving endless belt by friction.

16. A method as in Claim 15 wherein one or more additional rollers force said belt against said driven conveyor end roller to drive said belt by friction, and wherein said driven roller is covered with rubber or plastic to increase friction with the belt.

17. A method as in Claim 2 or 5 wherein said top flight slides over flat bar grating.

18. A method as in Claim 17 wherein said flat bar grating under the top flight is in a chevron pattern to assist in keeping said top flight in tracking alignment.

19. A method as in Claim 17 wherein the flat bars of said flat bar grating are metal and are heated by passing electric current through said bars.

20. A method as in Claim 5 wherein said top flight passes under a hot radiator or under or over a bank of hot pipes.

21. A method as in Claim 20 wherein said radiator or the pipes of said bank of pipes are heated internally by a hot fluid.

22 A method as in Claim 9, 12 or 15 wherein at least one of said conveyor end rollers or stationary belt guides is heated.

23. A method as in Claim 1, 2 or 5 wherein a jet or jets of fluid under pressure are used to remove bitumen and bitumen wetted mineral from said top flight.

24. A method as in Claim 2, 5 or 21 wherein air is circulated through the top flight of said belt to blow bitumen and bitumen wetted minerals from said top flight into the receiver mounted under said top flight.

25. A method as in Claim 23 wherein said fluid under pressure is di-hydrogen oxide in the form of cold water, warm water, hot water or steam.

26 A method as in Claim 23 wherein said fluid under pressure is a cold, warm or hot hydrocarbon solvent that dilutes the bitumen on the top belt flight and facilitates its falling from the top flight.

27. A method as in Claim 26 wherein air is circulated through the apertures of said top flight to blow bitumen and hydrocarbon solvent from the top flight surfaces before these surfaces return to the bottom flight.

28. A method as in Claim 10 wherein electric primary coils are mounted above said top flight, which primary coils are excited by alternating current flowing through them to cause alternating magnetic flux to pass through said spiral wound wires and cross rods of said belt along the top flight to cause heating of said spiral wound wires and cross rods and removal of bitumen and bitumen wetted minerals from said top flight.

29. A method as in Claim 2 or 5 wherein said top flight passes through one or more induction ovens, in which the inside walls of said induction ovens form the secondary coils of induction circuits to heat and remove bitumen and minerals from said top flight.

30. A method as in Claim 2 or 5 wherein the apertures in said endless belt are between 0.1 and 20 square centimeters each in area cross section.

31. A method as in Claim 30 wherein the apertures in said endless belt are between 0.6 and 6 square centimeters each in area cross section.

32. A method as in Claim 2 or 5 wherein the width of said endless belt is between 1 and 25 meters and the length of said belt, before it is joined into an endless belt, is between 5 and 100 meters.

33. A method as in Claim 32 wherein the width of said end-less belt is between 3 and 10 meters and the length of said belt, before it is joined into an endless belt, is between 10 and 30 meters.

34. A method as in Claim 2 or 5 wherein one or more guides or rollers are mounted inside said inverted arch or catenary adja-cent to said belt to prevent or reduce swinging of said belt.

35. A method as in Claim 2 or 5 wherein one or more guides or rollers are mounted outside said inverted arch or catenary adjacent to said belt to prevent or reduce swinging of said belt.

36. A method as in Claim 3 wherein baffles are provided on front and rear walls to reduce the flow of mixture between said walls and the edges of said endless belt along the inverted arch or catenary.

37. A method as in Claim 34 wherein said guides or rollers deform said inverted arch or catenary into a form approaching a triangle or a rectangle.

38. A method as in Claim 2 or 5 wherein said mixture has a temperature between zero degrees centigrade and eighty degrees centigrade.

39. A method as in Claim 38 wherein said mixture has a temperature between zero degrees centigrade and forty degrees centigrade.

40. A method as in Claim 38 wherein the bitumen in said mixture has a viscosity between 10,000 and 5,000,000 centipoises.

41. A method as in Claim 40 wherein the bitumen in said mixture has a viscosity between 150,000 and 1,500,000 centipoises.

42. A method as in Claim 2 or 5 wherein said mixture is a screened slurry of oil sand dispersed in water.

43. A method as in Claim 2 or 5 wherein said mixture is a bitumen product from a previous step of recovering bitumen and bitumen wetted minerals by a method as in Claim 2 or 5.

44. A method as in Claim 2 or 5 wherein said mixture is a stream of tailings from a mined oil sands plant or from a previous step of recovering bitumen and bitumen wetted minerals by a method as in Claim 1, 2 or 5.

45. A method as in Claim 2 or 5 wherein said mixture is a tailings pond sludge from a mined oil sands plant.

46. A method as in Claim 2 or 40 wherein said belt is mount-ed on a barge floating on a tailings pond wherein the bottom belt flight hangs down into the mixture of the tailings pond, comes in contact with bodies or mats of bitumen floating in said mixture in said pond, causing adhesion of bitumen of said bodies or mats to said belt and causing conveyance of said adhering bitumen to the top flight from where the adhering bitumen falls into a receiver under the top flight.

47. A method as in Claim 2 or 5 wherein said mixture is from an oil well.

48. A method as in Claim 2 or 5 wherein said mixture is a mineral ore from a mineral mine mixed with bitumen and water.

49. A method as in Claim 2 or 5 wherein said mixture is a mineral ore from a placer deposit mixed with bitumen and water.

50. A method as in Claim 2 or 5 wherein the recovered product of bitumen and bitumen wetted mineral is diluted with naphtha and centrifuged to separate it into minerals and a minerals reduced bitumen product.

51. An apparatus for the separation of bitumen and bitumen wetted minerals from a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, which apparatus comprises:

a) a container for containing a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, b) a movable apertured oleophilic endless belt supported in such a manner that its path includes a top flight that is substantially horizontal and is above the normal level of mixture in the container, and a bottom flight that hangs in the shape of an inverted arch or catenary or that hangs in a shape that approximates to an inverted arch or catenary, and that extends down to below the said normal level so that a portion of the bottom flight is in the mixture during operation of the apparatus, c) a receiver located beneath the top flight of the apertured belt to receive bitumen which in operation falls from the belt, d) means to revolve the endless belt, whereby in operation bitumen and bitumen wetted minerals adhere to the apertured belt as the belt rises from the mixture and bitumen and bitumen wetted minerals fall from the top flight of the apertured belt into the receiver located beneath the top flight of the belt.

52. An apparatus as in Claim 51 wherein the apertured belt is supported by at least two supports located above the normal level of the mixture in such manner that the top flight extends substantially horizontally between the supports and the bottom flight extends between the supports in an inverted arch or catenary, or in a shape that approximates to an inverted arch or catenary.

53. An apparatus as in Claim 52 wherein front and rear walls are provided adjacent to the edges of the endless belt along the normally immersed portions of the bottom flight, to direct flow of the mixture through the belt apertures.

54. An apparatus as in Claim 53 wherein said container for containing said mixture is provided with an inlet for admission of the mixture to the container and an outlet for removal of depleted mixture from the container.

55. An apparatus as in Claim 51, 52 or 54 wherein said endless belt is a flat wire open mesh metal belt comprising a large number of long and narrow flat strips of metal each formed into a shape resembling approximately a square wave with sloping sides, said strips being at least provided with two holes near the top and two holes near the bottom of each square wave to accept metal cross rods that pass through said holes and join said strips into a flexible continuous endless belt.

56. An apparatus as in Claim 51, 52 or 54 wherein said endless belt is a spiral mesh belt comprising a large number of spiral wound metal wires that are joined into a flexible continuous endless belt by the same large number of connecting rods, each passing through pairs of meshing spirals to form a continuous belt of multiple hinges of metal wire.

57 An apparatus as in Claim 56 wherein said belt is a spiral mesh belt and the apparatus includes electrical coils mounted above said top flight which coils can be provided with alternating electric current such that said spiral mesh belt can be heated by means of induction.

58. An apparatus as in Claim 51, 52 or 54 wherein said end-less belt resembles a multistrand roller chain comprising a large number of linkages, each linkage having at least two holes, which linkages are joined with cross rods that pass through said holes in said linkages to form an endless belt and in which said link-ages are uniformly spaced on said cross rods.

59. An apparatus as in Claim 55 whereon said endless belt is supported by at least one conveyor shaft with sprockets with teeth, or by at least one conveyor pin roller with pins, which teeth or pins can engage with said belt and can drive said belt.

60. An apparatus as in Claim 51 wherein said endless belt is supported by at least one conveyor roller which can drive said belt by friction.

61. An apparatus as in Claim 55 wherein a roller chain is attached to one or both edges of said endless belt.

62. An apparatus as in Claim 51, 52 or 54 wherein said top flight slides over grating.

63. An apparatus as in Claim 62 wherein said grating is flat bar metal grating.

64. An apparatus as in Claim 51, 52 or 54 wherein said top flight slides under or over a bank of pipes which pipes are fitted to accept hot fluid inside said pipes.

65. An apparatus as in Claim 51, 52 or 54 wherein the top flight of said endless belt is enclosed to retain heat and vapors.

66. An apparatus as in Claim 54 wherein two extra conveyor rollers are installed along the top flight that allow said top flight to double back to increase the total length of the top flight in comparison to the length of said bottom flight.

67. An apparatus as in Claim 51, 52 or 54 and arranged so that depleted mixture leaving the apparatus enters a second apparatus as in Claims 51, 52 or 54 for a second step of recovering bitumen and bitumen wetted minerals, the two apparatus being arranged to operate in cascade.

68. An apparatus as in Claim 51, 52 or 54 and arranged so that bitumen and bitumen wetted mineral leaving the apparatus enter a second apparatus as in Claims 51, 52 or 54 for a second step of recovering bitumen and bitumen wetted minerals, the two apparatus being arranged to operate in cascade.

69. An apparatus as in Claim 51 for the recovery of bitumen mats from a tailings pond, wherein said container for containing said mixture is said tailings pond.

70. An apparatus as in Claim 69 for removing bitumen mats from tailings pond sludge prior to moving said sludge through a pipeline, wherein the suction pipe of the pump that is to supply the pipeline is located inside the inverted arch or catenary of the bottom flight.

71. An apparatus as in Claim 51, 52 or 69 wherein said endless belt is made by joining two parallel roller chains at each chain link with cross rods of which the ends attach to extended roller pins of the roller chains.

72. A method as in Claim 2 or 5 wherein said top flight is conveyed over a bank of conveyor rollers.

73. A method as in Claim 72 wherein said conveyor rollers are heated.

74. An apparatus as in Claim 51, 55 or 56 wherein said top flight is conveyed over conveyor rollers.

75. An apparatus as in Claim 51 wherein a bank of nozzles is provided adjacent to said bottom flight above the said normal level of mixture for the purpose of providing fine sprays of water to wash minerals from the bottom flight as it emerges from said mixture.

76. An apparatus as in Claim 51 wherein a bank of nozzles is provided adjacent to said top flight for the purpose of providing a spray of fluid to wash bitumen from the top flight into said receiver beneath the top flight.

77. An apparatus for moving bitumen upward out of a container comprising an endless belt, or an endless chain, that has an affinity for bitumen and that is partly immersed in the bitumen in said container such that when said belt or chain moves bitumen is conveyed upward and out of said container.

78. An apparatus as in Claim 77 wherein said chain or belt is supported by a first sprockets or pulley that is immersed in the bitumen in said container and by a second sprocket or pulley, not immersed, that is mounted above said first sprocket or pulley and that is driven to cause movement of the chain or belt.

79. An apparatus as in Claim 78 wherein said chain or belt passes through a narrow passage or orifice adjacent to said second sprocket or pulley which orifice strips bitumen from said chain or belt.

80. An apparatus as in Claim 79 wherein said chain or belt is partly enclosed in a pipe or channel.