CA2867834A1

CA2867834A1 - Tailings solvent recovery unit feed control

Info

Publication number: CA2867834A1
Application number: CA2867834A
Authority: CA
Inventors: Alexander William Hyndman; John Patrick Ringstrom; John Sharpe; Douglas Robert Bartlett; W. Scott Hindle; Chris L. Grant
Original assignee: Fort Hills Energy LP
Current assignee: Fort Hills Energy LP
Priority date: 2004-01-08
Filing date: 2004-01-08
Publication date: 2005-07-08
Anticipated expiration: 2024-01-08
Also published as: CA2867834C

Abstract

Techniques for treating a bitumen froth can include adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth; separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component; providing the diluted tailings component to a solvent recovery apparatus at a separating step temperature sufficient to avoid pressure moderation of the diluted tailings component and/or adding a dilution stream into the diluted tailings component to produce a tailings solvent recovery feed stream; and then separating feed stream into a recovered solvent component and a solvent recovered tailings component.

Description

TAILINGS SOLVENT RECOVERY UNIT FEED CONTROL
TECHNICAL FIELD
This invention relates to processes and apparatus for the treatment of product streams which result from mineral processing operations, including the treatment of tailings which result from oil sand processing operations.
BACKGROUND OF THE INVENTION
Oil sand extraction processes are used to liberate and separate bitumen from oil sand so that the bitumen can be further processed to produce synthetic crude oil.
Numerous oil sand extraction processes have been developed and commercialized, many of which involve the use of water as a processing medium. One such water extraction process is the Clark hot water extraction process (the "Clark Process"), which was one of the first commercially successful oil sand extraction processes.
A water extraction process such as the Clark Process typically requires that mined oil sand be conditioned for extraction by being crushed to a desired lump size and then combined with water and perhaps other agents to form a conditioned slurry of water and crushed oil sand. In the Clark Process, the water used is "hot" (about 95 degrees Celsius) and an amount of sodium hydroxide (caustic) is added to the slurry to adjust the slurry pH
upwards, which enhances the liberation and separation of bitumen from the oil sand.
Other water extraction processes may have other temperature requirements and may include other conditioning agents which are added to the oil sand slurry.
Regardless of the type of oil sand extraction process employed, the process will typically result in the production of a number of product streams, some of which are typically disposed of as waste. For example, in the Clark Process, these streams include a bitumen froth stream comprising bitumen, asphaltenes, fine particulate solids and water, a middlings stream comprising bitumen, asphaltenes, fine particulate solids and water, and a coarse tailings stream consisting essentially of coarse particulate solids and water. The bitumen froth stream and the middlings stream are typically processed further, both to recover and purify bitumen and to render the fine solids more readily disposable and less of an environmental risk. The coarse tailings stream is not typically processed further, since the coarse particulate solids are relatively easy to dispose of and do not typically present a significant environmental risk.
The bitumen froth stream is processed in a froth treatment process to recover water from the bitumen and to encourage the precipitation of asphaltenes out from the bitumen. The processed bitumen froth stream is then sent for further processing to produce synthetic crude oil. The fine solids and precipitated asphaltenes recovered from the bitumen froth stream are typically ultimately disposed of in tailings ponds.
The middlings stream is processed to recover additional bitumen and to recover water from the fine solids and any precipitated asphaltenes. The fine solids and precipitated asphaltenes recovered from the middlings stream are typically ultimately disposed of in tailings ponds.
The coarse solids previously obtained from the coarse tailings stream may be used to form dykes or berms to contain the fine solids. The water which is recovered from the bitumen froth stream and from the middlings stream may be recycled for re-use in various stages of the processes described above in order to recover valuable heat contained in the water, thus reducing the energy requirements of the various processes.
The froth treatment process reduces the fine solids, asphaltene and water content of the bitumen froth. The froth treatment process typically involves the addition of an organic solvent to dilute the bitumen. The solvent is typically either a naphtha (aromatic) solvent or a paraffinic (saturated aliphatic) solvent. The diluted bitumen froth is typically subjected to a multistage separation process to separate a diluted tailings component (including fine solids and precipitated asphaltenes) from a diluted bitumen component. The diluted bitumen component and the diluted tailings component produced by the multistage separation process are each subsequently subjected to a solvent recovery process.
Recovery of the solvent from the diluted bitumen component is required before the bitumen may be delivered to a refining facility for further processing.
Recovery of the solvent from the diluted tailings component is also desirable for several reasons, since any solvent remaining in the tailings will be discarded with the tailings in a tailings pond.
First, a loss of solvent becomes an unnecessary expenditure of the extraction process.
Second, any solvent remaining in the tailings pond becomes an environmental concern.

Third, water in a tailings pond may be recycled and any solvent remaining in this water may create explosive conditions when reheated for re-use in the various processes.
The middlings stream is processed for two main reasons. The first reason to process the middlings stream is to recover amounts of bitumen which remain suspended in the middlings stream. This bitumen is recovered both to maximize the recovery of bitumen from the oil sand and to reduce the amount of bitumen contained in the middlings stream.
Since the water recovered from the middlings stream may be heated and recycled for re-use, bitumen remaining in the water may foul heat exchangers and cause a need for increased maintenance of plant equipment.
The second reason to process the middlings stream is to recover water from the middlings stream so that the middlings can be more efficiently disposed of in a tailings pond. The middlings stream contains most of the fine solids from the oil sand, which fine solids tend to settle and consolidate very slowly when their water content is high.
Complete settlement and consolidation of the fine material suspended in water may take many years. Furthermore, water not recovered from the middlings stream creates a requirement for makeup water which decreases the overall efficiency of the various processes.
Processes and apparatus relating to the treatment of bitumen froth are described in the prior art. These processes and apparatus include those described in Canadian Patent No.
1,027,501 (Simmer), Canadian Patent No. 1,267,860 (Hann), Canadian Patent No.
1,293,465 (Hyndman et al), Canadian Patent No. 2,021,185 (Tipman et al), Canadian Patent No. 2,149,737 (Tipman et al), Canadian Patent Application No. 2,200,899 (Tipman et al), Canadian Patent Application No. 2,232,929 (Power et al), Canadian Patent Application No. 2,350,907 (Duyvesteyn et al), U.S. Pat. No. 4,035,282 (Stuchberry et al) and U.S. Pat. No. 6,007,709 (Duyvestyn et al).
Other bitumen extraction and related processes include those described in Canadian Patent Application No. 2,053,016 (Green et al), Canadian Patent No. 2,055,213 (Wallace et al), U.K. Patent Application No. 2,044,796 (Robinson et al), U.S. Pat. No.

4,324,652 (Hack), U.S. Pat. No. 4,425,227 (Smith), U.S. Pat. No. 4,545,892 (Cymbalisty et al), U.S.
Pat. No. 4,722,782 (Graham et al) and U.S. Pat. No. 5,143,598 (Graham et al).
=

Processes and apparatus relating to the preparation of oil sand slurries and conditioning of oil sand slurries include those described in Canadian Patent No. 2,029,795 (Cymerman et al), Canadian Patent Application No. 2,191,517 (Tipman), Canadian Patent No.
2,195,604 (Maciejewski et al), U.S. Pat. No. 4,120,775 (Murray et al), U.S.
Pat. No.

5,039,227 (Leung et al), U.S. Pat. No. 5,264,118 (Cymerman et al), U.S. Pat.
No.
5,954,277 (Maciejewski et al), U.S. Pat. No. 6,007,708 (Allcock et al) and U.S. Pat. No.

6,076,753 (Maciejewski et al).
There remains in the art a need for increased efficiency and effectiveness in treating both the bitumen froth stream and the middlings stream which are produced in the processing of oil sand.
SUMMARY OF THE INVENTION
The present invention relates to the treatment of tailings which result from mineral processing operations, such as oil sand processing operations. The tailings comprise particulate solids and may also comprise precipitated asphaltenes. The tailings are preferably comprised of fine particulate solids and precipitated asphaltenes and are preferably produced as a tailings component from a bitumen froth or from a middlings stream.
In a first aspect, the invention relates to a process for treating a bitumen froth, wherein the process comprises a solvent adding step for adding a solvent to the bitumen froth to provide a diluted bitumen froth, wherein the process comprises a separating step for separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes, and wherein the process comprises a solvent recovering step for separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the improvement which comprises:
(a) introducing the diluted tailings component into a solvent recovery apparatus following the separating step;
(b) discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component; and (c) returning a portion of the discharged solvent recovered tailings component to the solvent recovery apparatus as a returned solvent recovered tailings component.
The reasons for returning a portion of the discharged solvent recovered tailings component to the solvent recovery apparatus are first, to increase the flowrate of liquids through the solvent recovery apparatus in order to inhibit the accumulation of an asphaltene mat which could plug the solvent recovery apparatus, second, to suppress foam which may be formed in the solvent recovery apparatus and third, to provide an opportunity to liberate and recover additional solvent from the returned portion of the discharged solvent recovered tailings component. As a result, any amount of recycling will be advantageous and the ratio by volume of the returned solvent recovered tailings component to the discharged solvent recovered tailings component may be any ratio which is less than 1:1. Preferably the ratio is greater than about 1:2.
Preferably the ratio is no greater than about 5:6.
The solvent recovery apparatus may be comprised of a single solvent recovery unit or a plurality of solvent recovery units configured in parallel or in series.
Preferably the solvent recovery apparatus is comprised of a plurality of solvent recovery units configured in series.
Where the solvent recovery apparatus is comprised of a plurality of solvent recovery units configured in series, the returned solvent recovered tailings component may be comprised of a returned portion of the solvent recovered tailings component discharged from one or a plurality of the solvent recovery units. Preferably the returned portion of a solvent recovered tailings component discharged from a solvent recovery unit is returned to the same solvent recovery unit. Alternatively, the returned portion of a solvent recovered tailings component discharged from a solvent recovery unit may be returned to a different solvent recovery unit or to more than one solvent recovery unit.
Preferably the solvent recovery apparatus is comprised of two or more solvent recovery units configured in series. In a preferred embodiment, a returned portion of the solvent recovered tailings component discharged from a first solvent recovery unit is returned to the first solvent recovery unit. Optionally, a returned portion of the solvent recovered tailings component discharged from one or more subsequent solvent recovery units is also returned to the same solvent recovery unit from which it was discharged.

The ratio by volume of the returned portion of a discharged solvent recovered tailings component to the discharged solvent recovered tailings component from a particular solvent recovery unit is greater than about 1:2, and preferably is no greater than about 5:6.
Preferably a moderated pressure is provided in the solvent recovery apparatus.

Preferably the moderated pressure is between about 1 atmosphere and about 2 atmospheres, which generally represents a pressure reduction prior to the solvent recovery apparatus. The reasons for providing a moderated pressure in the solvent recovery apparatus are first, to minimize slug formation in the transfer lines to the solvent recovery apparatus, second, to minimize transfer line erosion and third, to assist in the breaking of foam which may have been produced during previous processing of the bitumen froth or the tailings component. The moderated pressure may be provided using a pressure relief valve, pressure regulator or any other apparatus or device which is capable of providing the moderated pressure in the solvent recovery apparatus, and may be provided upstream of the solvent recovery apparatus or within the solvent recovery apparatus.
The returned solvent recovered tailings component may be returned to the solvent recovery apparatus in any suitable manner. Preferably the returned solvent recovered tailings component is exposed to shearing conditions before being returned to the solvent recovery apparatus. The reasons for exposing the returned solvent recovered tailings component to shearing conditions are first, to break up asphaltene flocs and second, to encourage further liberation of solvent from the tailings component.
The shearing conditions may be provided by mixers, pumps or similar apparatus.
In a preferred embodiment, the shearing conditions are provided by utilizing a recycle pump to return the returned solvent recovered tailings component to the solvent recovery apparatus.
Preferably the process is further comprised of the step of thickening at least a portion of the discharged solvent recovered tailings component in order to produce a thickener underflow component and a thickener overflow component.

, The separating step for separating the diluted bitumen froth into a diluted bitumen component and a diluted tailings component may comprise any suitable process which utilizes a diluent solvent. The solvent may be comprised of any suitable solvent.
Preferably the solvent is an organic solvent. The organic solvent is preferably comprised of a naphtha (aromatic) solvent or a paraffinic (saturated aliphatic) solvent.
Most preferably the solvent is comprised of a paraffinic solvent.
The separating step may be comprised of one or a plurality of separating steps which may be configured in series or in parallel. Preferably the separating step is comprised of a plurality of separating steps performed in series. Preferably the solvent is added to a separating step which is subsequent to a first separating step. Preferably the diluted bitumen froth is removed from the separating step at a first separating step and the diluted tailings component is removed from the separating step at a final separating step.
Preferably a portion of the thickener overflow component is returned to the separating step as a returned thickener overflow component. The returned thickener overflow component may be distributed to one or more of the separating steps.
Preferably the returned thickener overflow component is returned to a separating step which is subsequent to the first separating step.
In a preferred embodiment, the separating step is comprised of the following steps:
(a) first separating the bitumen froth into a first separating stage overflow component and a first separating stage underflow component;
(b) adding a solvent to the first separating stage underflow component to provide a diluted first separating stage underflow component;
(c) second separating the diluted first separating stage underflow component into a second separating stage overflow component and a second separating stage underflow component, wherein the second separating stage underflow component is comprised of the diluted tailings component;
(d) returning the second separating step overflow component to the first separating step so that the second separating step overflow component mixes with the bitumen froth to provide the diluted bitumen froth.

In a preferred embodiment the returned thickener overflow component is returned to the second separating step.
The separating step is preferably performed in a separator apparatus. The separator apparatus may be comprised of one or a plurality of separator units which may be configured in series or in parallel. The separator units may be comprised of any suitable apparatus, including but not limited to separator vessels or plate separators.
Preferably the separator apparatus is comprised of a plurality of separator units configured in series. Preferably the solvent is added to a separator unit which is subsequent to a first separator unit. Preferably the diluted bitumen froth is removed from the separator apparatus at the first separator unit and the diluted tailings component is removed from the separator apparatus at the final separator unit.
Preferably a portion of the thickener overflow component is returned to the separator apparatus as a returned thickener overflow component. The returned thickener overflow component may be distributed to one or more of the separator units. Preferably the returned thickener overflow component is returned to a separator unit which is subsequent to the first separator unit. In a preferred embodiment, the separator apparatus is comprised of two separator units and the returned thickener overflow component is returned to a second separator unit.
The reasons for returning the returned thickener overflow component to the separating step and the separating apparatus are first, to dilute the bitumen froth which is being separated and second, to conserve energy by using recycled clarified water from the thickening step as a water diluent rather than fresh water which may require heating.
The separating step is performed at a temperature which is dependent upon the composition of the solvent. Paraffinic solvents generally require a lower temperature for the separating step than do naphtha solvents and lighter paraffinic solvents generally require a lower temperature for the separating step than do heavier paraffinic solvents.
In the preferred embodiment where the separating step is comprised of a first separating step and a second separating step, the second separating step is preferably performed at a higher temperature than the first separating step so that the temperature of the second separating step controls the temperature at which the first separating step is performed.

Preferably the temperature of the second separating step is controlled by providing a heat input to the second separating step. Preferably the heat input is provided by adding the solvent to the second separating step at a temperature which is suitable to control the operating temperature for both the second separating step and the first separating step.
In a second aspect, the invention relates to a process for treating a bitumen froth, wherein the process comprises a solvent adding step for adding a solvent to the bitumen froth to provide a diluted bitumen froth, wherein the process comprises a separating step for separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes, and wherein the process comprises a solvent recovering step for separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the improvement which comprises:
(a) introducing the diluted tailings component into a solvent recovery apparatus following the separating step;
(b) discharging the solvent recovered tailings component from the solvent recovery apparatus; and (c) thickening at least a portion of the solvent recovered tailings component to produce a thickener underflow component and a thickener overflow component.
The second aspect of the invention may include additional features, including any or all of those features which are described above with respect to the first aspect. For example, the second aspect may include the step of returning a portion of the discharged solvent recovered tailings component to the solvent recovery apparatus as a returned solvent recovered tailings component so that features of the first aspect and the second aspect are combined.
In a third aspect, the invention is an apparatus for treating a bitumen froth comprising:
(a) a solvent recovery apparatus for separating a diluted tailings component recovered from the bitumen froth into a recovered solvent component and a solvent recovered tailings component;

(b) a discharge outlet for discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component;
and (c) a return line for returning a portion of the discharged solvent recovered tailings component to the solvent recovery apparatus as a returned solvent recovered tailings component.
In a fourth aspect, the invention is an apparatus for treating a bitumen froth comprising:
(a) a solvent recovery apparatus for separating a diluted tailings component recovered from the bitumen froth into a recovered solvent component and a solvent recovered 10 tailings component;
(b) a discharge outlet for discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component;
and (c) a thickener vessel associated with the solvent recovery apparatus for thickening at least a portion of the discharged solvent recovered tailings component to produce a thickener underflow component and a thickener overflow component.
In a fifth aspect, the invention is a process for treating tailings to recover therefrom a clarified overflow component, an unclarified overflow component and an underflow component, comprising the following steps:
(a) introducing the tailings into a thickener vessel;
(b) withdrawing the underflow component from a lower level of the thickener vessel;
(c) withdrawing the clarified overflow component from an intermediate level of the thickener vessel; and (d) withdrawing the unclarified overflow component from an upper level of the thickener vessel.

In a sixth aspect, the invention is a thickener vessel comprising:
(a) a sidewall defining a lower level of the thickener vessel, an intermediate level of the thickener vessel and an upper level of the thickener vessel;
(b) a feedwell for introducing tailings into the thickener vessel;
(c) at least one underflow outlet in communication with the lower level of the thickener vessel for withdrawing an underflow component from the thickener vessel;
(d) at least one clarified overflow outlet in communication with the intermediate level of the thickener vessel for withdrawing a clarified overflow component from the thickener vessel; and (e) at least one unclarified overflow outlet in communication with the upper level of the thickener vessel for withdrawing an unclarified overflow component from the thickener vessel.
The thickener vessel of the third and fourth aspects may be comprised of any suitable receptacle which is capable of receiving tailings and of implementing the tailings treatment process of the invention. For example, the thickener vessel may be above ground or below ground and may have any shape or size. The thickener vessel may be uncovered, covered or sealed. In the preferred embodiment the thickener vessel is generally cylindrical in plan view.
The thickener vessel includes a sidewall. The sidewall defines the height of the thickener vessel and defines the levels of the thickener vessel. The sidewall may be constructed of any suitable material and may have any suitable shape. For example, if the thickener vessel is to be sealed and is likely to contain volatile materials, the sidewall and other components of the thickener vessel may be designed as a pressure vessel. In other applications, the thickener vessel may be below ground and may be comprised of a lined or unlined pit or trench.
In the preferred embodiment the thickener vessel is constructed of metal, preferably steel, and has a continuous sidewall. In the preferred embodiment, the sidewall is substantially vertical throughout the upper level and the intermediate level and is sloped throughout at least a portion of the lower level, thus providing a sloping cone-shaped bottom. The cone shaped bottom assists in the collection and removal at the underflow outlet of the underflow component of the tailings. In the preferred embodiment, the sidewall further defines a sump at a central location within the lower level of the thickener vessel for collecting the underflow component.
The purpose of the process of the third aspect and the thickener vessel of the fourth aspect is to recover from the tailings a clarified overflow component, an unclarified overflow component and an underflow component. The objective in separating the overflow component into a clarified overflow component and an unclarified overflow component is to provide the clarified overflow component which can be recycled without further processing and which will not risk fouling of heat exchangers and other apparatus due to the presence of significant amounts of solids and/or other impurities.
As a result, preferably the process is performed and the thickener vessel is configured to enhance the separation of the tailings into these three components and to maximize the efficiency of the overall tailings treatment process.
One important mechanism for achieving the purpose of the third aspect and the fourth aspect is effectively configuring the location or locations at which tailings are introduced to the thickener vessel and the locations at which overflow and underflow components are removed from the thickener vessel. A second important mechanism for achieving the purpose is configuring the thickener vessel overall so that the tailings are provided with an opportunity to separate into the three output streams and so that the three output streams are directed towards the appropriate outlets.
The tailings are comprised of solids or other impurities which are suspended or dispersed in a liquid medium. The tailings treatment process and the thickener vessel are designed to exploit differences in the densities and other properties of the solids, other impurities and the liquid medium.
The tailings may be obtained from any chemical or mechanical process in which tailings are generated and in which the generated tailings are capable of being separated into an underflow component, an unclarified overflow component and a clarified overflow component.

In the preferred embodiment, the tailings are derived from either the bitumen froth stream or the middlings stream resulting from an oil sand extraction process. The liquid medium is therefore typically water, the solids typically comprise asphaltenes or fine solids such as clay or silt, and the other impurities typically include bitumen or perhaps other hydrocarbons such as diluent solvents.
In the preferred embodiment the underflow component is comprised of a thickened suspension of solids and/or other impurities which are more dense than the liquid medium. The unclarified overflow component is comprised of solids and/or other impurities which are less dense than the liquid medium. The clarified overflow component consists essentially of the liquid medium, but may also include a small amount of solids and/or other impurities.
The tailings treatment process and the thickener vessel are therefore designed so that the underflow and overflow components are withdrawn from the thickener vessel at different levels which reflect the densities of the constituents of the underflow and overflow components.
The tailings are introduced into the thickener vessel at a feedwell and the underflow and overflow components are withdrawn from the thickener vessel at their respective outlets.
The feedwell may be positioned at any suitable location in the thickener vessel. The underflow outlet may be positioned at any suitable location within the lower level of the thickener vessel. The clarified overflow outlet may be positioned at any suitable location within the intermediate level of the thickener vessel. The unclarified overflow outlet may be positioned at any suitable location within the upper level of the thickener vessel.
Preferably the feedwell is positioned in spaced relation relative to the sidewall, preferably the underflow component outlet is positioned adjacent to the lower end of the thickener vessel, preferably the clarified overflow outlet is positioned at a location adjacent to the sidewall, and preferably the unclarified overflow outlet is positioned at a location adjacent to the sidewall.
In a preferred embodiment the sidewall defines a thickener area and the feedwell is positioned in spaced relation relative to the sidewall and in a central location within the thickener area. In a preferred embodiment the feedwell extends within the thickener vessel so that the tailings are introduced into the thickener vessel at the intermediate level of the thickener vessel.
Preferably the tailings are distributed within the thickener vessel after they are introduced into the thickener vessel. Preferably the thickener vessel comprises a distributor apparatus and the tailings are distributed by contacting the distributor apparatus as they enter the thickener vessel. In a preferred embodiment the distributor apparatus is comprised of a cone shaped distributor plate which deflects the tailings outwardly and downwardly as they enter the thickener vessel.
The thickener vessel may further comprise a launder for collecting the unclarified overflow component before it is withdrawn from the thickener vessel. The launder may comprise a trough adjacent to and extending along all or a portion of the sidewall of the thickener vessel and may further comprise a weir over which the unclarified overflow component must pass in order to enter the launder. Where the thickener vessel includes a launder, the unclarified overflow outlet communicates with the launder to withdraw the unclarified overflow component from the thickener vessel.
The thickener vessel may comprise one or a plurality of feedwells, underflow outlets, clarified overflow outlets and unclarified overflow outlets. In a preferred embodiment, the thickener vessel comprises a single feedwell, a single underflow outlet, a plurality of clarified overflow outlets, and a single unclarified overflow outlet which communicates with a launder. Preferably the plurality of clarified overflow outlets comprises four clarified overflow outlets distributed and spaced circumferentially about the sidewall.
The tailings treatment process may include the step of adding a flocculant to the tailings to enhance the settling of the underflow component. The flocculant may be added to the tailings in the thickener vessel or it may be added to the tailings before they enter the thickener vessel.
The tailings treatment process may further comprise the step of passing a gas upwards through the tailings in the thickener vessel in order to enhance the clarification of the clarified overflow component, and the thickener vessel may be further comprised of a sparge apparatus for delivering the gas. Preferably the gas is air but other gases, including inert gases, may be used.

The gas is preferably passed upwards through the tailings at a position which is between the feedwell and the clarified overflow outlets so that the gas provides a curtain of bubbles through which the clarified overflow component may pass before being withdrawn from the thickener vessel. The sparge apparatus is therefore preferably located between the clarified overflow outlets and the feedwell.
The thickener vessel may further comprise a baffle arrangement for stilling the clarified overflow component before it is withdrawn from the thickener vessel. The baffle arrangement may also provide a sinuous path for the clarified overflow component to assist in the removal of solids and/or other impurities from the clarified overflow 10 component before it is withdrawn from the thickener vessel.
Preferably a baffle arrangement substantially or completely surrounds each of the clarified overflow outlets. A baffle arrangement may extend upward or downward within the thickener vessel. Preferably a baffle arrangement does not interfere significantly with the path of the clarified overflow component as it moves through the curtain of bubbles and toward a clarified overflow outlet.
In a preferred embodiment, a baffle arrangement substantially or completely surrounds each of the clarified overflow outlets and each baffle arrangement extends downward a short distance from above the clarified overflow outlet so that it terminates at a point above the clarified overflow outlet.
Preferably the sparge apparatus and the baffle arrangement are configured so that the baffle arrangement is located within the thickener vessel between the sparge apparatus and the clarified overflow outlet.
In a preferred embodiment a sparge apparatus is associated with each baffle arrangement such that the sparge apparatus is suspended from a lower end of the baffle arrangement. The sparge apparatus may be suspended from the lower end of the baffle arrangement in any suitable manner. In a preferred embodiment the sparge apparatus is suspended from the lower end of the baffle arrangement with sparge apparatus hangers which are spaced and configured so that they do not interfere significantly with the movement of the clarified overflow component toward the clarified overflow outlet.

In some scenarios, there is provided a process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids, precipitated asphaltenes and foam; providing the diluted tailings component from the separating step to a solvent recovery apparatus at a separating step temperature sufficient to avoid pressure moderation of the diluted tailings component; separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component. The separating comprises introducing the diluted tailings component into the solvent recovery apparatus; and discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component.
In some scenarios, there is provided a process for treating a bitumen froth, comprising:
adding a paraffinic solvent containing stream to the bitumen froth to provide a diluted bitumen froth; separating the diluted bitumen froth into a diluted bitumen component and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes; adding a dilution stream into the diluted tailings component to produce a tailings solvent recovery feed stream; providing the tailings solvent recovery feed stream to a tailings solvent recovery apparatus; and separating the tailings solvent recovery feed stream into a recovered solvent component and a solvent recovered tailings component.
In some scenarios, there is provided a process for treating a bitumen froth, comprising:
adding a paraffinic solvent containing stream to the bitumen froth to provide a diluted bitumen froth; separating the diluted bitumen froth into a diluted bitumen component and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes; diluting the diluted tailings component to produce a tailings solvent recovery feed stream; providing the tailings solvent recovery feed stream to a tailings solvent recovery apparatus; and separating the tailings solvent recovery feed stream into a recovered solvent component and a solvent recovered tailings component.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 is a schematic flow diagram of preferred embodiments of processes of the present invention implemented in conjunction with an oil sand extraction process.
FIG. 2 is a plan view of a thickener vessel in accordance with a preferred embodiment of the invention.
FIG. 3 is a transverse cross section view of the thickener vessel of FIG. 2 taken along line 3-3.
FIG. 4 is a schematic diagram of the thickener vessel of FIGS. 2 and 3, depicting the introduction of tailings into the thickener vessel and the withdrawal from the thickener vessel of an underflow component, a clarified overflow component and an unclarified overflow component.
DETAILED DESCRIPTION
The present invention relates to processes and apparatus for the treatment of product streams from mineral processing operations. The present invention is particularly suited to the treatment of tailings from such processes and is even more particularly suited to the treatment of tailings which comprise relatively fine solids and other impurities.
In preferred embodiments of the invention, the invention relates to the treatment of tailings obtained from oil sand processing operations and in particular, to the treatment of tailings which are obtained from either the bitumen froth stream or the middlings stream of a process for recovering bitumen from oil sand. In the preferred embodiments, the tailings are obtained from oil sand extraction processes such as the Clark Process or other comparable processes.
Preferred embodiments of the present invention are outlined in the flow diagram of FIG. 1, depicting processes of the present invention implemented in conjunction with the Clark Process or a comparable oil sand extraction process and FIGS. 2-4, which depict a thickener vessel according to a preferred embodiment of the invention.
Referring to FIG. 1, an exemplary oil sand extraction process (20) includes a number of steps. The first step is a mining step (not shown) in which oil sand is removed from an oil sand deposit. The second step is a crushing step (22) in which the mined oil sand is crushed into lumps of a desired size.
The third step is a conditioning step (24) in which the oil sand is mixed with water to form a slurry. Conditioning agents may also be added to the oil sand as part of the conditioning step. For example in the Clark Process, sodium hydroxide (caustic) is typically added to the oil sand slurry during the conditioning step (24) in order to maintain the slurry at a slightly basic pH.
Following the conditioning step (24) a transportation step (26) transports the oil sand slurry to a primary separation vessel (PSV) (28). The transportation step (26) is typically performed by transporting the oil sand slurry in a pipeline.
The oil sand is also typically heated as part of the conditioning step (24) or the transportation step (26) in order to raise the temperature of the oil sand to the oil sand extraction process (20) operating temperature.
In the PSV (28), a primary recovery step occurs in which the oil sand slurry is separated into three different product streams. The first product stream is a bitumen froth stream (30). The second product stream is a middlings stream (32). The third product stream is a coarse tailings stream (34).
The coarse tailings stream (34) typically consists of relatively coarse particles of solid material which is present either as sand, gravel or non-dispersed fine solid material such as clay and/or silt. The coarse tailings stream (34) may typically be disposed of without further processing in a coarse tailings disposal step (36). The coarse tailings in the coarse tailings stream (34) may be used, for example, to construct berms or dykes (not shown) as part of a fine tailings containment facility.
The bitumen froth stream (30) typically includes bitumen, asphaltenes, dispersed fine solid material such as clay and/or silt and water. The bitumen froth stream (30) is typically further processed following the oil sand extraction process (20) to remove water, asphaltenes and fine solid material and thus purify the bitumen as a preliminary step towards upgrading of the bitumen to a synthetic crude oil.

As will be described in detail in the description that follows, the processing of the bitumen froth stream (30) typically results in the separation of the bitumen froth stream (30) into a bitumen froth component and a tailings component. This tailings component may be characterized as "fine tailings" comprising dispersed fine solid material. The present invention is directed in part at the treatment, following the oil sand extraction process (20), of the tailings component which is obtained from processing of the bitumen froth stream (30).
The middlings stream (32) typically includes fine solid material such as clay and/or silt, water, and a relatively small amount of bitumen and asphaltenes. The middlings stream (32) is typically further processed as part of the oil sand extraction process (20) in a secondary recovery step to recover additional bitumen from the middlings stream (32).
This secondary recovery step is typically performed by passing the middlings stream (32) through a series of flotation cells (38).
The secondary recovery step typically results in the separation of the middlings stream (32) into a secondary bitumen froth stream (40) and middlings tailings (42).
The secondary bitumen froth stream (40) is typically recycled to be combined with conditioned oil sand slurry and is thus reintroduced to the PSV (28).
The middlings tailings (42) may be characterized as "fine tailings" comprising dispersed fine solid material. The present invention is directed in part at the treatment of the middlings tailings (42) which result from the secondary recovery step in the oil sand extraction process (20).
The invention therefore relates generally to the treatment of fine tailings and is particularly suited to the treatment of fine tailings obtained from an oil sand extraction process (20) or a related process. In the description that follows, the invention will be described in the context of the treatment of a tailings component resulting from further processing of the bitumen froth stream (30) and in the context of the treatment of middlings tailings (42) resulting from secondary recovery of bitumen from the middlings stream (32).
Referring to FIG. 1, the bitumen froth stream (30) exits the PSV (28) and is transferred to a deaerator apparatus (44) in which entrained air in the bitumen froth stream (32) is removed.

From the deaerator apparatus (44) the bitumen froth stream (30) enters a separator apparatus (46). The separator apparatus (46) may be comprised of one or a plurality of separator units which may be configured in series or in parallel. The separator units may be comprised of separator vessels, plate separators or other separator equipment.
In the preferred embodiment the separator apparatus (46) is comprised of a first separator unit (48) and a second separator unit (50) configured in series, both of which separator units (48,50) are separator vessels. The separator apparatus (46) may, however, be comprised of more or fewer than two separator units.
The separator apparatus (46) is configured to perform a separating step. In the preferred 10 embodiment the separating step includes a first separating step performed in the first separator unit (48) and a second separating step performed in the second separator unit (50). The separating step utilizes a diluent solvent (52) which is added to the bitumen froth stream (30) to dilute the bitumen froth stream (30) and thus enhance the performance of the separating step.
The purpose of the separating step is to separate the bitumen froth stream (30) into a diluted bitumen component (54) and a diluted tailings component (56).
The diluted bitumen component (54) may be discharged from the separator apparatus (46) at both the first separator unit (48) and the second separator unit (50).
In the preferred embodiment, however, the separator apparatus (46) is configured to operate in 20 a "countercurrent" manner. In other words, the diluted bitumen component (54) is preferably discharged from the separator apparatus (46) only at the first separator unit (48) and the diluted tailings component (56) is preferably discharged from the separator apparatus (46) only at the second separator unit (50).
This result is achieved by recycling back to the first separator unit (48) the diluted bitumen component which is discharged from the second separator unit (50) so that the diluted bitumen component (54) is only discharged from the separator apparatus (46) at the first separator unit (48). Conversely, the diluted tailings component which is discharged from the first separator unit (48) passes through to the second separator unit (50) so that the diluted tailings component (56) is only discharged from the separator apparatus (46) at the second separator unit (50).

The diluent solvent (52) is preferably added to the second separator unit (50) so that the diluent solvent (52) is added to the first separator unit (48) only indirectly by recycling back to the first separator unit (48) the diluted bitumen component which is discharged from the second separator unit (50).
Adding the diluent solvent (52) to the second separator unit (50) provides several advantages. First, the loading of diluent solvent (52) in the bitumen froth stream (30) will be higher in the second separator unit (50) than in the first separator unit (48). This results in a more diluted bitumen froth stream (30) in the second separator unit (50), which may assist in recovering bitumen which was not recoverable in the first separator unit (48).
Second, since the separator apparatus (46) is preferably configured to operate in a countercurrent manner, adding the diluent solvent (52) to the second separator unit (50) provides an opportunity to regulate the operating temperatures of both the first separating step and the second separating step by controlling the temperature and loading of the diluent solvent (52) which is added to the second separator unit (50). In the preferred embodiment, the diluent solvent (52) is heated to a suitable temperature to ensure that the operating temperatures in the first separator unit (48) and the second separator unit (50) are compatible with the properties of the bitumen froth stream (30) and the selected diluent solvent (52).
Third, the addition of the diluent solvent (52) only to the second separator unit (50) permits optimization of the amount of diluent solvent (52) which is used in the separating step, since the maximum loading of diluent solvent (52) is provided in the second separating step where it is most needed.
The performance of the separating step is dependent to some extent upon the properties of the diluent solvent (52) which is used in the separating step. It is known in the art to use either naphtha (aromatic) solvents or paraffinic (saturated aliphatic) solvents as the diluent solvent in the treatment of bitumen froth. Other organic and inorganic solvents may also potentially be used as the diluent solvent (52).
Some of the advantages of paraffinic solvents in comparison with naphtha solvents are discussed in Canadian Patent No. 2,149,737 (Tipman et al).

The required operating temperature of the separating step and the amount of diluent solvent (52) required for the separating step will be somewhat dependent upon the choice of diluent solvent (52). Naphtha solvents tend to have larger, more complex molecules than paraffinic solvents and thus tend to require d higher operating temperature for the separating step and larger amounts of solvent than do paraffinic solvents.
Similarly, heavier, longer chain paraffinic solvents tend to require a higher operating temperature for the separating step and larger amounts of solvent than do lighter, shorter chain paraffinic solvents. The energy requirements and diluent solvent (52) requirements of the separating step may therefore typically be reduced by selecting a paraffinic solvent over a naphtha solvent and by selecting a relatively lighter paraffinic solvent over a relatively heavier paraffinic solvent.
Consideration should, however, be given in the selection of the diluent solvent (52) to the propensity of a particular solvent to cause precipitation of asphaltenes from the bitumen froth stream (30). Since asphaltenes are essentially hydrocarbons, their precipitation during the separating step should be managed to minimize loss of hydrocarbons from the diluted bitumen component and to minimize the amount of asphaltenes which are contained in the diluted tailings component (56). Excessive precipitation of asphaltenes during the separating step may also result in excessive formation of an asphaltene "rag layer" in the separator apparatus (46), which rag layer may interfere with the efficient performance of the separating step.
Asphaltenes tend to exhibit greater solubility in longer chain paraffinic solvents than in shorter chain paraffinic solvents, with the result that the amount of asphaltenes precipitated decreases as the selected paraffinic solvent becomes heavier or longer chained. Asphaltene precipitation is therefore generally greater in pentane than it is in hexane, heptane or octane.
The precipitation of asphaltenes from the bitumen froth stream (30) is also dependent upon the selection of the operating temperature for the separating step. The amount of asphaltenes precipitated from a particular solvent will generally decrease as the operating temperature is increased.
Finally, the precipitation of asphaltenes from the bitumen froth stream is also dependent upon the amount of diluent solvent (52) which is added to the bitumen froth stream (30).

The amount of asphaltenes precipitated from a particular solvent will generally increase as the amount of the solvent increases.
As a result of these considerations, the type of diluent solvent (52), the amount of diluent solvent (52) and the operating temperature of the separating step should all be selected with the goal of minimizing the cost and maximizing the efficiency of the separating step.
In the preferred embodiment, the diluent solvent (52) is preferably a paraffinic solvent and is preferably a paraffinic solvent having an overall carbon chain length of between C5 and 08. Depending upon the specific paraffinic solvent selected, the operating temperature required for the separating step may vary between about 60 degrees Celsius and about 130 degrees Celsius.
In the preferred embodiment, the operating temperature of the separating step is controlled by directly controlling the temperature in the second separator unit (50) and thus the temperature during the second separating step. As a result, preferably the first separating step is performed at a temperature which is lower than the temperature at which the second separating step is performed.
In the preferred embodiment, the operating temperature of the second separating step is controlled by providing a heat input to the second separating step. Due to the recycling back to the first separator unit (48) of the diluted bitumen component from the second separator unit (50), the operating temperature of the first separating step is indirectly controlled. In the preferred embodiment the heat input is provided to the second separating step by heating the diluent solvent (52) before it is added to the second separator unit (50).
By way of example, where the diluent solvent (52) is pentane, the second separating step may be performed at a temperature of about 90 degrees Celsius while the first separating step may be performed at a temperature of about 70 degrees Celsius.
Following completion of the separating step, the diluted bitumen component (54) is passed through a bitumen solvent recovery apparatus (58) in order to recover diluent solvent (52) from the diluted bitumen component (54) and produce a solvent recovered bitumen component (60).

The bitumen solvent recovery apparatus (58) may be comprised of any suitable apparatus such as, for example, a sub-atmospheric vessel with an associated condenser for separating the diluent solvent (52) from the diluted bitumen component (54) and recovering the diluent solvent (52). The bitumen solvent recovery apparatus (58) may be comprised of one or a plurality of bitumen solvent recovery units configured in series or in parallel. The diluent solvent (52) recovered in the bitumen solvent recovery apparatus (58) may be re-used in the separating step and the solvent recovered bitumen component (60) may be stored or transported for upgrading.
Following completion of the separating step, the diluted tailings component (56) is passed through a tailings solvent recovery apparatus (62) for a solvent recovering step in which the diluted tailings component (56) is separated into a recovered solvent component (64) and a solvent recovered tailings component (66).
The tailings solvent recovery apparatus (62) may be comprised of any suitable apparatus and may be similar to the bitumen solvent recovery apparatus (58). The tailings solvent recovery apparatus (62) may be comprised of one or more tailings solvent recovery units configured in series or in parallel. In the preferred embodiment the tailings solvent recovery apparatus (62) is comprised of at least two tailings solvent recovery units configured in series.
Referring to FIG. 1, in the preferred embodiment the tailings solvent recovery apparatus (62) includes a first tailings solvent recovery unit (68) and a second tailings solvent recovery unit (70).
The diluted tailings component (56) is transferred from the second separator unit (50) through a pressure moderating apparatus (72) such as a valve, regulator or other suitable device to moderate the pressure of the diluted tailings component (56), in order first to minimize the formation of slug flow through the transfer line, second to minimize transfer line erosion, and third to assist in the breakdown of foam which may be created during the separating step. This moderation of pressure may not be necessary if the separating step has been performed at an operating temperature which does not require significant pressurization of the bitumen froth stream (30).

From the pressure moderating apparatus (72) the diluted tailings component (56) is transferred to the first tailings solvent recovery unit (68) to obtain an amount of the recovered solvent component (64). The solvent recovered tailings component discharged from the first tailings solvent recovery unit (68) exits via a first discharge outlet (73) and is passed through a first recycle pump (74) to expose the solvent recovered tailings component to shearing conditions in order to break up asphaltene flocs and encourage further liberation of solvent from the solvent recovered tailings component.
From the first recycle pump (74) a portion of the solvent recovered tailings component discharged from the first tailings solvent recovery unit (68) is returned via a first return line 10 (75) to the first tailings solvent recovery unit (68) in order to increase the downward flux in the first tailings solvent recovery unit (68), inhibit the formation of an asphaltene mat or rag layer in the bottom of the first tailings solvent recovery unit (68), and suppress the formation of foam.
The non-returned portion of the solvent recovered tailings component discharged from the first tailings solvent recovery unit (68) is transferred to the second tailings solvent recovery unit (70) to recover a further amount of the recovered solvent component (64).
Optionally, the solvent recovered tailings component discharged from the second tailings solvent recovery unit (70) is passed via a second discharge outlet (77) through a second recycle pump (76) in order to expose the solvent recovered tailings component to 20 shearing conditions and thus break up asphaltene flocs and encourage further liberation of solvent from the solvent recovered tailings component.
From the second recycle pump (76) a portion of the solvent recovered tailings component discharged from the second tailings solvent recovery unit (70) is optionally returned via a second return line (79) to the second tailings solvent recovery unit (70) in order to increase the downward flux in the second tailings solvent recovery unit (70), inhibit the formation of an asphaltene mat or rag layer in the bottom of the second tailings solvent recovery unit (70), and suppress the formation of foam.
The non-returned portion of the diluted tailings component discharged from the second tailings solvent recovery unit (70) constitutes the solvent recovered tailings component (66) and is transferred to a first thickener vessel (78) for thickening.

The second recycle pump (76) and the return of a portion of the solvent recovered tailings component which is discharged from the second tailings solvent recovery unit (70) may be optional, since the formation of an asphaltene mat and the formation of foam has been observed to be more prevalent in the first tailings solvent recovery unit (68) than in the second tailings solvent recovery unit (70).
In the first thickener vessel (78) the solvent recovered tailings component (66) is thickened to produce a thickener underflow component (80) and a thickener overflow component (82). The thickener underflow component (80) may be disposed of in a fine tailings disposal step (84), which may involve depositing the thickener underflow component in a tailings pond (not shown) or similar facility.
In the preferred embodiment, a portion of the thickener overflow component (82) is returned to the separator apparatus (46) via a thickener return line (83) as a returned thickener overflow component (86). In particular, the returned thickener overflow component (86) is preferably transferred to the second separator unit (50) to dilute the diluted tailings component (56) to minimize plugging of the transfer line to the tailings solvent recovery apparatus (62) by asphaltene slugs and to conserve heat energy contained in the returned thickener overflow component (86). Preferably the returned thickener overflow component (86) is at a temperature close to the operating temperature of the tailings solvent recovery apparatus (62) to avoid quenching of the diluted tailings component (56) and resulting interference with the operation of the tailings solvent recovery apparatus (62).
The non-returned portion of the thickener overflow component (82) may optionally be transferred to clarifying apparatus (not shown) to prepare the thickener overflow component (82) for recycling.
Referring to FIG. 1, in the preferred embodiment the middlings tailings (42) obtained from the middlings stream (32) are transferred from the flotation cells (38) to one or more hydrocyclones (88) or other separation apparatus in order to separate the middlings tailings (42) into a solid material stream (90) and a fine tailings stream (92). The solid material stream (90) typically comprises relatively coarse particles of solid material and may typically be disposed of without further processing in similar manner as the coarse tailings stream (34) either as part of the coarse tailings disposal step (36) or in a separate step.
The fine tailings stream (92) from the hydrocyclones (88) is transferred to a second thickener vessel (94). The fine tailings stream (92) typically comprises relatively fine particles of solid material, other impurities such as asphaltenes and a small amount of bitumen dispersed in a relatively large proportion of water. The objective in treating the fine tailings stream (92) in the second thickener vessel (94) is first, to concentrate the solid material and other impurities and second, to clarify and recover as much water as possible for possible recycling.
In a conventional thickener vessel, tailings are separated into an underflow component and an overflow component. In the conventional processing of oil sand, the overflow component will invariably contain small amounts of bitumen, which can foul heat exchanger equipment if the overflow component is directly recycled for reheating and re-use. As a result, steps must typically be taken to clarify further the overflow component from a conventional thickener vessel before the overflow component can be recycled.
In the preferred embodiment of the present invention the design of the second thickener vessel (94) facilitates the recovery of an underflow component (91), an unclarified overflow component (93), and a clarified overflow component (95) which preferably is sufficiently clean that it can be recycled back to the oil sand extraction process (20) or related processes without further treatment or clarification.
Referring to FIGS. 2-4, a preferred embodiment of the second thickener vessel (94) is depicted. The second thickener vessel (94) includes a sidewall (96) which extends from the lowest elevation of the second thickener vessel (94) to the highest elevation of the second thickener vessel (94). The sidewall (96) therefore defines the height of the second thickener vessel (94) and defines several different levels of the second thickener vessel (94).
At least one underflow outlet (98) communicates with a lower level (100) of the second thickener vessel (94). At least one, but preferably a plurality of clarified overflow outlets (102) communicate with an intermediate level (104) of the second thickener vessel (94).

At least one unclarified overflow outlet (106) communicates with an upper level (108) of the second thickener vessel (94).
Referring to FIG. 2, the sidewall (96) also defines a thickener area (110). In the preferred embodiment the thickener area (110) is generally circular but the thickener area (110) may be square, rectangular or any other suitable shape.
Referring to FIG. 2, a feedwell (112) is located generally centrally within the thickener area (110). The feedwell (112) comprises a relatively large inlet conduit which extends downward into the intermediate level (104) of the second thickener vessel (94).
The underflow outlet (98) is preferably located within a sump (114) which is near to the lowest elevation of the second thickener vessel (94) and is preferably located generally centrally within the thickener area (110). The sidewall (96) is preferably sloped downwards towards the sump (114) and the underflow outlet (98) throughout at least a portion of the lower level (100) of the second thickener vessel (94). The underflow outlet (98) is associated with a pump (116) for pumping the underflow component (91) from the underflow outlet (98).
The clarified overflow outlets (102) are preferably located adjacent to the sidewall (96). In the preferred embodiment, four clarified overflow outlets (102) are spaced circumferentially around the sidewall (96).
Associated with each of the clarified overflow outlets (102) is a baffle arrangement (118) for stilling the clarified overflow component (95) before it reaches the clarified overflow outlet (102) and for providing a sinuous path for the clarified overflow component (95) to further facilitate the clarification of the clarified overflow component (95).
In the preferred embodiment each baffle arrangement (118) is comprised of a baffle plate which surrounds the clarified overflow outlet (102). The baffle plate extends downward from above the clarified overflow outlet (102) and terminates above the clarified overflow outlet (102) to permit the clarified overflow component (95) to access the clarified overflow outlet (102) without significant interference from the baffle plate.
A sparge apparatus (120) is provided within the second thickener vessel (94) for passing a gas upwards through the fine tailings stream (92). The sparge apparatus (120) is comprised of a perforated pipe through which a gas such as air can be passed to provide a curtain of gas bubbles.
The sparge apparatus (120) is located at an elevation below the clarified overflow outlets (102) and between the feedwell (112) and the clarified overflow outlets (102) so that the clarified overflow component (95) may pass through a curtain of gas bubbles before reaching one of the clarified overflow outlets (102).
The sparge apparatus (120) may be comprised of a single continuous length of perforated pipe or may be comprised of a plurality of segments of perforated pipe. The sparge apparatus (120) may be distributed throughout the entire second thickener vessel (94), may be provided as a "ring" or "rings" within the second thickener vessel (94) or may be localized adjacent to the clarified overflow outlets (102).
In the preferred embodiment the sparge apparatus (120) is associated with the baffle arrangements (118). More particularly, in the preferred embodiment a separate segment of the sparge apparatus (120) is suspended from each of the baffle arrangements (118) with a plurality of sparge apparatus hangers (121). The sparge apparatus hangers (121) are configured so that they do not interfere significantly with the movement of the clarified overflow component (95) toward the clarified overflow outlets (102).
The unclarified overflow outlet (106) is preferably located adjacent to the sidewall of the second thickener vessel (94). In the preferred embodiment, the unclarified overflow outlet (106) is associated with a launder (122) located at the upper level (108) of the second thickener vessel (94) so that the unclarified overflow component (93) is first collected in the launder (122) and then withdrawn from the second thickener vessel (94) by the unclarified overflow outlet (106).
In the preferred embodiment the launder (122) is comprised of a trough (124) which extends along the entire length of the sidewall (96) adjacent to the highest elevation of the second thickener vessel (94), and is further comprised of a weir (126) over which the unclarified overflow component (93) must pass in order to enter the launder (122).
The fine tailings stream (92) from the hydrocyclones (88) enters the second thickener vessel (94) via the feedwell (112) and the separated components (91,93,95) are withdrawn from the second thickener vessel (94) at the outlets (98,106,102) respectively.

To assist in dispersing the fine tailings stream (92) throughout the second thickener vessel (94), the second thickener vessel (94) preferably includes a distributor apparatus (128). In the preferred embodiment the distributor apparatus (128) is comprised of a cone-shaped distributor plate which is located adjacent to the feedwell (112).
The operation of the second thickener vessel (94) is depicted schematically in FIG. 4. The fine tailings stream (92) enters the second thickener vessel (94) via the feedwell (112), contacts the distributor apparatus (128) and is dispersed throughout the second thickener vessel (94). A flocculant may be added to the second thickener vessel (94) either by premixing the flocculant with the fine tailings stream (92) or by separately adding the 10 flocculant to the second thickener vessel (94) at the feedwell (112) or at some other location.
Fine solid material and some other impurities contained within the fine tailings stream (92) tend to floc together and fall downwards in the second thickener vessel (94) towards the underflow outlet (98) where they may be withdrawn as the underflow component (91). The sloped portion of the sidewall (96) assists in directing the underflow component (91) towards the underflow outlet (98).
Bitumen and other relatively buoyant impurities contained within the fine tailings stream (92) tend to move upwards in the second thickener vessel (94) and move towards the sidewall (96) where they can pass over the weir (126), enter the launder (122) and be 20 withdrawn via the unclarified overflow outlet (106) as the unclarified overflow component (93). The upward movement of the bitumen and other impurities may be assisted by the curtain of gas bubbles provided by the sparge apparatus (120).
Relatively clear water will be stilled by the baffle arrangements (118) and will move toward one of the clarified overflow outlets (102) to be withdrawn from the second thickener vessel (94) as the clarified overflow component (95). Clarification of the clarified overflow component (95) will be enhanced by the curtain of gas bubbles provided by the sparge apparatus (120).
The underflow component (91) may be pumped via the pump (116) for disposal in similar manner to the thickener underflow component (80) obtained during the processing of the 30 bitumen froth stream (30), such as in a tailings pond or similar facility.

The unclarified overflow component (93) may be sent for further clarification to remove and recover the bitumen and other impurities, or it may be recycled to the PSV
(28), the separator apparatus (46), the flotation cells (38) or some other equipment or process which does not require heating of the unclarified overflow component (93).
The clarified overflow component (95) may typically be used directly as recycle water for the oil sand extraction process (20) or a related process without risk of fouling heat exchanger or other equipment. One advantage of recycling the clarified overflow component (95) is that valuable energy can be conserved in the overall oil sand processing operation due to the heat retained by the clarified overflow component (95).
The relative proportions of the underflow component (91), the unclarified overflow component (93) and the clarified overflow component (95) withdrawn from the second thickener vessel (94) may be controlled by controlling the volumetric flowrate of the fine tailings stream (92) entering the second thickener vessel (94), the volumetric flowrate of the underflow component (91) withdrawn from the underflow outlet (98) and the volumetric flowrate of the clarified overflow component (95) withdrawn from the clarified overflow outlets (102).
The processes and apparatus of the present invention may be utilized as part of either a continuous or batch process. These processes and apparatus provide means for managing and treating product streams from mineral processing operations, and are particularly suited to the treatment of relatively fine tailings obtained from the bitumen froth stream (30) or the middlings stream (32) resulting from an oil sand extraction process (20).

Claims

1 In a process for treating a bitumen froth, wherein the process comprises a solvent adding step for adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth, wherein the process comprises a separating step for separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes, and wherein the process comprises a solvent recovering step for separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the improvement which comprises:
introducing the diluted tailings component into a solvent recovery apparatus following the separating step;
discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component; and returning a portion of the discharged solvent recovered tailings component to the solvent recovery apparatus as a returned solvent recovered tailings component.

2. The process of claim 1, wherein the ratio by volume of the returned solvent recovered tailings component to the discharged solvent recovered tailings component is no greater than about 5.6.

3. The process of claim 1 or 2, comprising the step of providing a moderated pressure in the solvent recovery apparatus

4 The process of claim 3, wherein the moderated pressure is between about 1 atmosphere and about 2 atmospheres or is sub-atmospheric.

5. The process of any one of claims 1 to 4, further comprising the step of exposing the returned solvent recovered tailings component to shearing conditions before returning the returned solvent recovered tailings component to the solvent recovery apparatus.

6. The process of claim 5, wherein the shearing conditions are provided by pumping the returned solvent recovered tailings component with a recycle pump.

7. The process of any one of claims 1 to 6, wherein the solvent recovery apparatus comprises a plurality of solvent recovery units configured in series.

8. The process of any one of claims 1 to 7, wherein the solvent recovery apparatus comprises a first solvent recovery unit, and wherein the returned solvent recovered tailings component comprises a returned portion of the solvent recovered tailings component discharged from the first solvent recovery unit.

9. The process of claim 8, wherein the returned portion of the solvent recovered tailings component discharged from the first solvent recovery unit is returned to the first solvent recovery unit.

10. The process of claim 8 or 9, wherein the ratio by volume of the returned portion of the discharged solvent recovered tailings component from the first solvent recovery unit to the discharged solvent recovered tailings component from the first solvent recovery unit is no greater than about 5:6.

11. The process of any one of claims 8 to 10, wherein the solvent recovery apparatus comprises the first solvent recovery unit and a second solvent recovery unit and wherein the returned solvent recovered tailings component is further comprised of a returned portion of the solvent recovered tailings component discharged from the second solvent recovery unit.

12. The process of claim 11, wherein the returned portion of the solvent recovered tailings component discharged from the second solvent recovery unit is returned to the second solvent recovery unit.

13. The process of claim 11 or 12, wherein the ratio by volume of the returned portion of the discharged solvent recovered tailings component from the second solvent recovery unit to the discharged solvent recovered tailings component from the second solvent recovery unit is no greater than about 5:6.

14. The process of any one of claims 1 to 13, comprising the step of thickening at least a portion of the discharged solvent recovered tailings component to produce a thickener underflow component and a thickener overflow component.

15. The process of any one of claims 1 to 14, wherein the separating step is performed in a separator apparatus, further comprising the step of returning a portion of the thickener overflow component to the separator apparatus as a returned thickener overflow component.

16. The process of claim 15, wherein the separator apparatus comprises plurality of separator units configured in series and wherein the returned thickener overflow component is distributed to one or more of the separator units.

17. The process of any one of claims 1 to 16, further comprising the separating step, wherein the separating step comprises the following steps:
(i) separating the bitumen froth into a first separating stage overflow component and a first separating stage underflow component;
(ii) adding a solvent to the first separating stage underflow component to provide a diluted first separating stage underflow component;
(iii) separating the diluted first separating stage underflow component into a second separating stage overflow component and a second separating stage underflow component, wherein the second separating stage underflow component comprises the diluted tailings component;
(iv) returning the second separating step overflow component to the first separating step so that the second separating step overflow component mixes with the bitumen froth to provide the diluted bitumen froth.

18. The process of claim 17, further comprising the step of returning a portion of the thickener overflow component to the separating step as a returned thickener overflow component.

19. The process of claim 18, wherein the returned thickener overflow component is returned to one or both of the first separating step and the second separating step.

20. The process of any one of claims 17 to 19, wherein the first separating step is performed at a temperature which is lower than a temperature at which the second separating step is performed.

21. The process of any one of claims 17 to 19, wherein the first separating step is performed at a temperature and wherein the second separating step is performed at a temperature, further comprising the step of providing a heat input to the second separating step in order to control the temperature of the first separating step and the temperature of the second separating step.

22. An apparatus for treating a bitumen froth comprising:
a solvent recovery apparatus for separating a diluted tailings component recovered from the bitumen froth into a recovered solvent component and a solvent recovered tailings component;
a discharge outlet for discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component; and a return line for returning a portion of the discharged solvent recovered tailings component to the solvent recovery apparatus as a returned solvent recovered tailings component.

23. The apparatus of claim 22, wherein the solvent recovery apparatus comprises a plurality of solvent recovery units configured in series.

24. The apparatus of claim 22 or 23, wherein the solvent recovery apparatus comprises a first solvent recovery unit and wherein the return line comprises a first return line which is adapted to return to the first solvent recovery unit a portion of the solvent recovered tailings component which is discharged from the first solvent recovery unit.

25. The apparatus of claim 24, wherein the first solvent recovery unit comprises a first discharge outlet for discharging the solvent recovered tailings component from the first solvent recovery unit.

26. The apparatus of claim 25, comprising a first shear apparatus associated with the first discharge outlet for shearing the solvent recovered tailings component which is discharged from the first solvent recovery unit.

27. The apparatus of claim 25 or 26, wherein the solvent recovery apparatus further comprises a second solvent recovery unit and wherein the return line further comprises a second return line which is adapted to return to the second solvent recovery unit a portion of the solvent recovered tailings component which is discharged from the second solvent recovery unit.

28. The apparatus of claim 27, wherein the second solvent recovery unit comprises a second discharge outlet for discharging the solvent recovered tailings component from the second solvent recovery unit.

29. The apparatus of claim 28, further comprising a second shear apparatus associated with the second discharge outlet for shearing the solvent recovered tailings component which is discharged from the second solvent recovery unit.

30. The apparatus of any one of claims 22 to 29, comprising a thickener vessel associated with the solvent recovery apparatus for thickening at least a portion of the discharged solvent recovered tailings component to produce a thickener underflow component and a thickener overflow component.

31. The apparatus of claim 30, wherein the solvent recovery apparatus is associated with a separator apparatus for separating the bitumen froth into a diluted bitumen component and the diluted tailings component, further comprising a thickener return line for returning at least a portion of the thickener overflow component to the separator apparatus as a returned thickener overflow component.

32. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes, separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating comprising:

introducing the diluted tailings component into a solvent recovery apparatus following the separating step;
discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component;
and returning a portion of the discharged solvent recovered tailings component to the solvent recovery apparatus as a returned solvent recovered tailings component.

33. The process of claim 32, wherein the ratio by volume of the returned solvent recovered tailings component to the discharged solvent recovered tailings component is no greater than about 5:6.

34. The process of claim 32 or 33, comprising the step of providing a moderated pressure in the solvent recovery apparatus.

35. The process of claim 34, wherein the moderated pressure is between about 1 atmosphere and about 2 atmospheres.

36. The process of any one of claims 32 to 35, further comprising the step of exposing the returned solvent recovered tailings component to shearing conditions before returning the returned solvent recovered tailings component to the solvent recovery apparatus.

37. The process of claim 36, wherein the shearing conditions are provided by pumping the returned solvent recovered tailings component with a recycle pump.

38. The process of any one of claims 32 to 37, wherein the solvent recovery apparatus comprises a plurality of solvent recovery units configured in series.

39. The process of any one of claims 32 to 38, wherein the solvent recovery apparatus comprises a first solvent recovery unit, and wherein the returned solvent recovered tailings component comprises a returned portion of the solvent recovered tailings component discharged from the first solvent recovery unit.

40. The process of claim 39, wherein the returned portion of the solvent recovered tailings component discharged from the first solvent recovery unit is returned to the first solvent recovery unit.

41. The process of claim 39 or 40, wherein the ratio by volume of the returned portion of the discharged solvent recovered tailings component from the first solvent recovery unit to the discharged solvent recovered tailings component from the first solvent recovery unit is no greater than about 5:6.

42. The process of any one of claims 39 to 41, wherein the solvent recovery apparatus comprises the first solvent recovery unit and a second solvent recovery unit and wherein the returned solvent recovered tailings component is further comprised of a returned portion of the solvent recovered tailings component discharged from the second solvent recovery unit.

43. The process of claim 42, wherein the returned portion of the solvent recovered tailings component discharged from the second solvent recovery unit is returned to the second solvent recovery unit.

44. The process of claim 42 or 43, wherein the ratio by volume of the returned portion of the discharged solvent recovered tailings component from the second solvent recovery unit to the discharged solvent recovered tailings component from the second solvent recovery unit is no greater than about 5:6.

45. The process of any one of claims 32 to 44, comprising the step of thickening at least a portion of the discharged solvent recovered tailings component to produce a thickener underflow component and a thickener overflow component.

46. The process of any one of claims 32 to 45, wherein the separating step is performed in a separator apparatus, further comprising the step of returning a portion of the thickener overflow component to the separator apparatus as a returned thickener overflow component.

47. The process of claim 46, wherein the separator apparatus comprises plurality of separator units configured in series and wherein the returned thickener overflow component is distributed to one or more of the separator units.

48. The process of any one of claims 32 to 47, further comprising the separating step, wherein the separating step comprises the following steps:
(I) separating the bitumen froth into a first separating stage overflow component and a first separating stage underflow component;
(II) adding a solvent to the first separating stage underflow component to provide a diluted first separating stage underflow component;
(Ill) separating the diluted first separating stage underflow component into a second separating stage overflow component and a second separating stage underflow component, wherein the second separating stage underflow component comprises the diluted tailings component;
(IV) returning the second separating step overflow component to the first separating step so that the second separating step overflow component mixes with the bitumen froth to provide the diluted bitumen froth.

49. The process of claim 48, further comprising the step of returning a portion of the thickener overflow component to the separating step as a returned thickener overflow component.

50. The process of claim 49, wherein the returned thickener overflow component is returned to one or both of the first separating step and the second separating step.

51. The process of any one of claims 48 to 50, wherein the first separating step is performed at a temperature which is lower than a temperature at which the second separating step is performed.

52. The process of any one of claims 48 to 51, wherein the first separating step is performed at a temperature and wherein the second separating step is performed at a temperature, further comprising the step of providing a heat input to the second separating step in order to control the temperature of the first separating step and the temperature of the second separating step.

53. A process for separating an oil sands mixture containing paraffins and precipitated asphaltenes into multiple components while inhibiting formation of asphaltene mat or rag layers, the process comprising:
introducing the oil sands mixture to a separation apparatus to induce separation and produce an upper component and a tailings component, the tailings component comprising the precipitated asphaltenes;
removing the upper component from the separation apparatus and discharging the tailings component from the separation apparatus;
returning a portion of the discharged tailings component to the separation apparatus as a returned tailings component in order to inhibit the formation of the asphaltene mat or rag layers in the separation apparatus.

54. The process of claim 53, wherein the ratio by volume of the returned tailings component to the discharged tailings component is no greater than about 5:6.

55. The process of claim 53 or 54, comprising the step of providing a moderated pressure in the separation apparatus.

56. The process of claim 55, wherein the moderated pressure is between about 1 atmosphere and about 2 atmospheres.

57. The process of any one of claims 53 to 56, further comprising the step of exposing the returned tailings component to shearing conditions before returning the returned tailings component to the separation apparatus.

58. The process of claim 57, wherein the shearing conditions are provided by pumping the returned tailings component with a recycle pump.

59. The process of any one of claims 53 to 58, wherein the separation apparatus comprises a plurality of separation units configured in series.

60. The process of any one of claims 53 to 59, wherein the separation apparatus comprises a first separation unit, and wherein the returned tailings component comprises a returned portion of the tailings component discharged from the first separation unit.

61. The process of claim 60, wherein the returned portion of the tailings component discharged from the first separation unit is returned to the first separation unit.

62. The process of claim 60 or 61, wherein the ratio by volume of the returned portion of the discharged tailings component from the first separation unit to the discharged tailings component from the first separation unit is no greater than about 5:6.

63. The process of any one of claims 60 to 62, wherein the separation apparatus comprises the first separation unit and a second separation unit and wherein the returned tailings component further comprises a returned portion of the tailings component discharged from the second separation unit.

64. The process of claim 63, wherein the returned portion of the tailings component discharged from the second separation unit is returned to the second separation unit.

65. The process of claim 63 or 64, wherein the ratio by volume of the returned portion of the discharged tailings component from the second separation unit to the discharged tailings component from the second separation unit is no greater than about 5:6.

66. The process of any one of claims 63 to 65, comprising sending a remainder of the discharged tailings component from the first separation unit to the second separation unit to induce further separation.

67. The process of any one of claims 60 to 66, wherein the returned portion of the discharged tailings component from the first separation unit is returned to a bottom part of the first separation unit.

68. The process of claim 67, wherein the returned portion of the discharged tailings component from the first separation unit is introduced into one side of the first separation unit.

69. The process of any one of claims 60 to 67, wherein the returned portion of the discharged tailings component from the second separation unit is returned to a bottom part of the second separation unit.

70. The process of claim 69, wherein the returned portion of the discharged tailings component from the second separation unit is introduced into one side of the second separation unit.

71. An apparatus for separating an oil sands mixture containing paraffins and precipitated asphaltenes into multiple components while inhibiting formation of asphaltene mat or rag layers, the apparatus comprising:
a separation vessel for separating the oil sands mixture into an upper component and a tailings component, the tailings component comprising the precipitated asphaltenes;
a discharge outlet for discharging the tailings component from the separation vessel as a discharged tailings component; and a return line for returning a portion of the discharged tailings component to the separation vessel as a returned tailings component in order to inhibit the formation of the asphaltene mat or rag layers in the separation vessel.

72. The apparatus of claim 71, wherein the separation vessel comprises a plurality of separation units configured in series.

73. The apparatus of claim 71 or 72, wherein the separation vessel comprises a first separation unit and wherein the return line comprises a first return line which is adapted to return to the first separation unit a portion of the tailings component which is discharged from the first separation unit.

74. The apparatus of claim 73, wherein the first separation unit comprises a first discharge outlet for discharging the tailings component from the first separation unit.

75. The apparatus of claim 74, comprising a first shear apparatus associated with the first discharge outlet for shearing the tailings component which is discharged from the first separation unit.

76. The apparatus of claim 74 or 75, wherein the separation vessel further comprises a second separation unit and wherein the return line further comprises a second return line which is adapted to return to the second separation unit a portion of the tailings component which is discharged from the second separation unit.

77. The apparatus of claim 76, wherein the second separation unit comprises a second discharge outlet for discharging the tailings component from the second separation unit.

78. The apparatus of claim 77, further comprising a second shear apparatus associated with the second discharge outlet for shearing the tailings component which is discharged from the second separation unit.

79. The apparatus of any one of claims 71 to 78, comprising a thickener vessel associated with the separation vessel for thickening at least a portion of the discharged tailings component to produce a thickener underflow component and a thickener overflow component.

80. An oil sands treatment process comprising:
mining oil sand from an oil sand deposit;
forming an oil sand slurry comprising heated water, particulate coarse and fine solid material, and bitumen and asphaltenes;
separating the oil sand slurry into first, second and third product streams, the first product stream comprising most of the bitumen and asphaltenes in the oil sand slurry, heated water and fine solid material, the second product stream comprising fine solid material, and bitumen and asphaltenes, and the third product stream comprising coarse solid material;
contacting the first product stream with a paraffinic solvent to form a mixture containing precipitated asphaltenes;
separating the mixture into a solvent diluted bitumen component and a solvent diluted tailings component comprising heated water, fine solid material, precipitated asphaltenes, and residual bitumen and paraffinic solvent;
recovering the paraffinic solvent from the solvent diluted bitumen component;

subjecting the solvent diluted tailings component to a solvent recovery separation to recover the paraffinic solvent in the solvent diluted tailings component as a recovered solvent component and produce a solvent recovered tailings component;
treating the solvent recovered tailings component; and providing a chemical agent to be present in the oil sands treatment process.

81. The process of claim 80, wherein the chemical agent comprises a flocculant.

82. The process of claim 81, wherein the flocculant is added to the solvent recovered tailings component within a thickener vessel.

83. The process of claim 81, wherein the flocculant is premixed with the solvent recovered tailings component prior to entering a thickener vessel.

84. The process of claim 81, wherein the flocculant and the solvent recovered tailings component are separately added to a thickener vessel.

85.1n a process for treating a bitumen froth, wherein the process comprises a solvent adding step for adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth, wherein the process comprises a separating step for separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes, the improvement in which the separating step comprises:
separating the bitumen froth into a first separating stage overflow component and a first separating stage underflow component;
adding a paraffinic solvent stream to the first separating stage underflow component to provide a diluted first separating stage underflow component;
separating the diluted first separating stage underflow component into a second separating stage overflow component and a second separating stage underflow component, wherein the second separating stage underflow component comprises the diluted tailings component;

returning the second separating step overflow component to the first separating step so that the second separating step overflow component combines with the bitumen froth to provide the diluted bitumen froth; and subjecting a separation stage input stream to mixing.

86. The process of claim 85, wherein the mixing is performed by passing the diluted bitumen froth through an in-line mixing unit prior to feeding into a corresponding one of the separation stages.

87. The process of claim 86, wherein the separation stage input stream comprises the diluted bitumen froth for separation in the first separating stage.

88. The process of claim 87, wherein the mixing is performed by passing the diluted bitumen froth through an in-line mixing unit prior to feeding into the first separation stage.

89. The process of claim 85, wherein the second separating step overflow component is combined with the bitumen froth by in-line addition.

90. The process of claim 89, wherein the in-line addition is performed such that the second separating step overflow component and the bitumen froth are flowed perpendicularly into each other.

91. The process of any one of claims 85 to 90, wherein the separation stage input stream comprises the first separating stage underflow component for separation in the second separating stage.

92. The process of claim 91, wherein the mixing of the first separating stage underflow component is performed by passing the first separating stage underflow component through an in-line mixing unit prior to feeding into the second separation stage.

93. The process of claim 92, wherein the addition of the paraffinic solvent stream to the first separating stage underflow component is performed by in-line addition.

94. The process of claim 93, wherein the in-line addition is performed such that the paraffinic solvent stream and the first separating stage underflow component are flowed perpendicularly into each other.

95. The process of any one of claims 85 and 94, comprising subjecting the first separating stage underflow component to shearing prior to the addition of the paraffinic solvent stream.

96. The process of claim 95, wherein the mixing of the first separating stage underflow component is performed after the shearing thereof and the addition of paraffinic solvent.

97. The process of claim 96, wherein the shearing is performed by a pump.

98. The process of any one of claims 85 and 97, comprising subjecting the bitumen froth to a deaerating step prior to the addition of the second separating step overflow component to the first separating step.

99. A process for separating an oil sands stream containing paraffinic solvent and precipitated asphaltenes into multiple components, the process comprising:
introducing the oil sands stream to a separation apparatus to induce separation and produce an upper component and a tailings component, the tailings component comprising precipitated asphaltenes;
removing the upper component from the separation apparatus and discharging the tailings component from the separation apparatus;
subjecting the oil sands stream to mixing in order to inhibit the formation of the asphaltene mat or rag layers in the separation apparatus.

100. The process of claim 99, wherein the mixing is performed by passing the oil sands stream through an in-line mixing unit.

101. The process of claim 100, comprising subjecting the oil sands stream to shearing prior to mixing in the in-line mixing unit.

102. The process of claim 101, wherein the shearing is performed by a pump.

103. An apparatus for treating an oil sands stream containing paraffinic solvent and precipitated asphaltenes and produce multiple components while inhibiting formation of asphaltene mat or rag layers, the apparatus comprising:
a separation apparatus for separating the oil sands stream into an upper component and a tailings component;
a discharge outlet for discharging the tailings component from the separation apparatus as a discharged tailings component; and an inlet line for feeding the separation apparatus with the oil sands stream;
a mixing unit associated with the inlet line for mixing the oil sands stream in order to inhibit the formation of the asphaltene mat or rag layers in the separation apparatus.

104. The apparatus of claim 103, wherein the separation apparatus comprises a plurality of separation units configured in series.

105. The apparatus of claim 103 or 104, wherein the separation apparatus comprises a first separation unit and wherein the inlet line comprises a first inlet line which is adapted to feed the first separation unit.

106. The apparatus of claim 105, wherein the mixing unit comprises a first mixing unit associated with the first inlet line.

107. The apparatus of claim 105 or 106, wherein the first separation unit comprises a first discharge outlet for discharging the tailings component from the first separation unit.

108. The apparatus of claim 107, comprising a first shear apparatus associated with the first discharge outlet for shearing the tailings component which is discharged from the first separation unit.

109. The apparatus of claim 108, wherein the first shear apparatus comprises a pump.

110. The apparatus of any one of claims 105 to 109, wherein the separation apparatus further comprises a second separation unit and wherein the inlet line further comprises a second inlet line which is adapted to feed the second separation unit the tailings component discharged from the first separation unit.

111. The apparatus of claim 110, wherein the mixing unit comprises a second mixing unit associated with the second inlet line.

112. The apparatus of claim 110 or 111, wherein the second separation unit comprises a second discharge outlet for discharging the tailings component from the second separation unit.

113. The apparatus of claim 112, wherein the separation apparatus further comprises a second separation unit and wherein the inlet line further comprises a second inlet line which is adapted to feed the second separation unit the tailings component discharged from the first separation unit.

114. The apparatus of claim 113, wherein the mixing unit comprises a second mixing unit associated with the second inlet line.

115. The apparatus of claim 112 or 113, wherein the second separation unit comprises a second discharge outlet for discharging the tailings component from the second separation unit.

116. The apparatus of any one of claims 113 to 115, wherein the second mixing unit is provided downstream from the shear apparatus.

117. The apparatus of claim 116, wherein the shear apparatus comprises a pump.

118. A process for treating a bitumen froth, the process comprising:
contacting the bitumen froth with a stream containing a paraffinic solvent to form a diluted bitumen mixture;

separating the diluted bitumen mixture into a diluted bitumen component and a diluted tailings component comprising paraffin-precipitated asphaltenes, the separating of the diluted bitumen mixture being performed in a separation apparatus comprising a plate separator;
removing the diluted bitumen component and the diluted tailings component from the separation apparatus.

119. The process of claim 118, the separation apparatus comprises a first and a second of the plate separator operated in series.

120. The process of claim 118, wherein the separating comprises:
separating the bitumen froth into a first separating stage overflow component and a first separating stage underflow component, in the first plate separator, wherein the first stage overflow component comprises the diluted bitumen component;
adding an amount of the paraffinic solvent to the first separating stage underflow component to provide a diluted first separating stage underflow component;
separating the diluted first separating stage underflow component into a second separating stage overflow component and a second separating stage underflow component, in the second plate separator, wherein the second separating stage underflow component comprises the diluted tailings component;
returning the second separating step overflow component to the first separating step so that the second separating step overflow component mixes with the bitumen froth to provide the diluted bitumen froth.

121. A high temperature counter-current paraffinic treatment process for treating a bitumen froth stream derived from an oil sands processing operation, the process comprising:

contacting the bitumen froth stream with a stream containing paraffinic solvent to produce a diluted bitumen mixture;
performing a separation step at a temperature between about 60°C and about 130°C, the separation step being performed in a two-unit separation apparatus, the separation step comprising:
feeding the diluted bitumen mixture into a first separation unit and producing a first diluted bitumen overflow component and a first tailings underflow component that are removed from the first separation unit;
adding paraffinic solvent to the first tailings underflow component to produce a first diluted tailings component;
feeding the first diluted tailings component to a second separation unit and producing a second diluted bitumen overflow component and a second tailings underflow component that are removed from the second separation unit;
recycling back the second diluted bitumen component to form at least part of the stream containing paraffinic solvent for contacting the bitumen froth stream;
recovering the paraffinic solvent from the first diluted bitumen component to produce a solvent recovered bitumen component; and recovering the paraffinic solvent from the second diluted tailings component to produce a solvent recovered tailings component.

122. The process of claim 121, wherein the paraffinic solvent recovered from the first diluted bitumen component and the second diluted tailings component is used as the paraffinic solvent added to the first tailings underflow component.

123. The process of claim 122, comprising condensing the recovered paraffinic solvent prior to adding to the first tailings underflow component.

124. The process of any one of claims 121 to 123, wherein all of the first diluted bitumen component is subjected to the step of recovering the paraffinic solvent therefrom.

125. The process of any one of claims 121 to 124, wherein all of the first diluted tailings component is fed to the second separation unit.

126. The process of any one of claims 121 to 125, wherein all of the second tailings component is subjected to the step of recovering the paraffinic solvent therefrom.

127. The process of any one of claims 121 to 126, wherein the separation step is performed between about 70°C and about 90°C.

128. The process of any one of claims 121 to 127, wherein the paraffinic solvent has an overall carbon chain length of between C5 and C8.

129. The process of claim 128, wherein the paraffinic solvent comprises pentane.

130. The process of claim 128, wherein the paraffinic solvent comprises hexane.

131. The process of claim 128, wherein the paraffinic solvent comprises heptane.

132. The process of claim 128, wherein the paraffinic solvent comprises octane.

133. A paraffinic treatment process for treating a bitumen froth stream derived from an oil sands processing operation, the process comprising:
contacting the bitumen froth stream with a stream containing paraffinic solvent to produce a diluted bitumen mixture;
performing a separation step in a two-unit separation apparatus, the separation step comprising:
feeding the diluted bitumen mixture into a first separation unit and producing a first diluted bitumen overflow component and a first tailings underflow component that are removed from the first separation unit;

adding paraffinic solvent to the first tailings underflow component to produce a first diluted tailings component, feeding the first diluted tailings component to a second separation unit and producing a second diluted bitumen overflow component and a second tailings underflow component that are removed from the second separation unit, recycling back the second diluted bitumen component to form at least part of the stream containing paraffinic solvent for contacting the bitumen froth stream, and controlling the amount of the paraffinic solvent added to the first tailings underflow component to provide higher paraffinic solvent loading in the second separation unit than in the first separation unit, thereby assisting bitumen recovery in the second separation unit.

134. The process of claim 133, wherein the temperature of the separation step is between about 60°C and about 130°C

135 The process of claim 133 or 134, wherein the temperature of the separation step is between about 70°C and about 90°C.

136. The process of any one of claims 133 to 135, comprising recovering the paraffinic solvent from the first diluted bitumen component to produce a solvent recovered bitumen component.

137 The process of claim 136, comprising recovering the paraffinic solvent from the second diluted tailings component to produce a solvent recovered tailings component.

138. The process of claim 137, wherein the paraffinic solvent recovered from the first diluted bitumen component and the second diluted tailings component is used as the paraffinic solvent added to the first tailings underflow component

139. The process of claim 138, comprising condensing the recovered paraffinic solvent prior to adding to the first tailings underflow component.

140. The process of any one of claims 133 to 139, wherein the paraffinic solvent has an overall carbon chain length of between C5 and C8.

141. The process of any claim 140, wherein the paraffinic solvent comprises pentane.

142. The process of claim 140 or 141, wherein the paraffinic solvent comprises hexane.

143. The process of any one of claims 140 to 142, wherein the paraffinic solvent comprises heptane.

144. The process of any one of claims 140 to 143, wherein the paraffinic solvent comprises octane.

145. A paraffinic treatment process for treating a bitumen froth stream derived from an oil sands processing operation, the process comprising:
contacting the bitumen froth stream with a stream containing paraffinic solvent to produce a diluted bitumen mixture;
performing a separation step in a two-unit separation apparatus, the separation step comprising:
feeding the diluted bitumen mixture into a first separation unit and producing a first diluted bitumen overflow component and a first tailings underflow component that are removed from the first separation unit;
adding paraffinic solvent to the first tailings underflow component to produce a first diluted tailings component;
feeding the first diluted tailings component to a second separation unit and producing a second diluted bitumen overflow component and a second tailings underflow component that are removed from the second separation unit;

recycling back the second diluted bitumen component to form at least part of the stream containing paraffinic solvent for contacting the bitumen froth stream;
and controlling the temperature of the paraffinic solvent added to the first tailings underflow component to indirectly regulate operating temperatures of the first separation unit.

146. The process of claim 135, wherein controlling of the temperature of the paraffinic solvent comprises heating the paraffinic solvent.

147. The process of claim 135 or 136, wherein controlling of the temperature of the paraffinic solvent is performed in accordance with properties of the bitumen froth stream and the properties of the paraffinic solvent.

148. The process of any one of claims 135 to 137, wherein the temperature of the first separation unit is regulated to be lower than the temperature of the first separation unit.

149. The process of any one of claims 135 to 138, wherein the operating temperature of the separation step is between about 60°C and about 130°C.

150. The process of claim 139, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

151. The process of any one of claims 135 to 140, comprising recovering the paraffinic solvent from the first diluted bitumen component to produce a solvent recovered bitumen component.

152. The process of any one of claims 141, comprising recovering the paraffinic solvent from the second diluted tailings component to produce a solvent recovered tailings component.

153. The process of claim 142, wherein the paraffinic solvent recovered from the first diluted bitumen component and the second diluted tailings component is used as the paraffinic solvent added to the first tailings underflow component.

154. The process of claim 143, comprising condensing the recovered paraffinic solvent prior to adding to the first tailings underflow component.

155. The process of any one of claims 145 to 154, wherein the paraffinic solvent has an overall carbon chain length of between C5 and C8.

156. The process of claim 155, wherein the paraffinic solvent comprises pentane.

157. The process of claim 155 or 155, wherein the paraffinic solvent comprises hexane.

158. The process of any one of claims 155 to 157, wherein the paraffinic solvent comprises heptane.

159. The process of any one of claims 155 to 158, wherein the paraffinic solvent comprises octane.

160. A high temperature counter-current paraffinic treatment process for treating a bitumen froth stream derived from an oil sands processing operation, the process comprising:
contacting the bitumen froth stream with a stream containing paraffinic solvent to produce a diluted bitumen mixture;
performing a separation step in a two-unit separation apparatus, the separation step comprising:
feeding the diluted bitumen mixture into a first separation unit and producing a first diluted bitumen overflow component and a first tailings underflow component that are removed from the first separation unit;
adding paraffinic solvent to the first tailings underflow component to produce a first diluted tailings component;
feeding the first diluted tailings component to a second separation unit and producing a second diluted bitumen overflow component and a second tailings underflow component that are removed from the second separation unit;
recycling back the second diluted bitumen component to form at least part of the stream containing paraffinic solvent for contacting the bitumen froth stream;
and selecting the paraffinic solvent to have an overall carbon chain length of between C5 and C5.

161. The process of claim 155, wherein the paraffinic solvent comprises pentane.

162. The process of claim 155, wherein the paraffinic consists of comprises pentane.

163. The process of claim 155, wherein the paraffinic solvent comprises hexane.

164. The process of claim 155, wherein the paraffinic solvent consists of hexane.

165. The process of claim 155, wherein the paraffinic solvent comprises heptane.

166. The process of claim 155, wherein the paraffinic solvent consists of heptane.

167. The process of claim 155, wherein the paraffinic solvent comprises octane.

168. The process of claim 155, wherein the paraffinic solvent consists of octane.

169. The process of any one of claims 160 to 168, wherein the operating temperature of the separation step is between about 60°C and about 130°C.

170. The process of claim 169, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

171. The process of any one of claims 160 to 170, comprising recovering the paraffinic solvent from the first diluted bitumen component to produce a solvent recovered bitumen component.

172. The process of any one of claims 171, comprising recovering the paraffinic solvent from the second diluted tailings component to produce a solvent recovered tailings component.

173. The process of claim 172, wherein the paraffinic solvent recovered from the first diluted bitumen component and the second diluted tailings component is used as the paraffinic solvent added to the first tailings underflow component.

174. The process of claim 173, comprising condensing the recovered paraffinic solvent prior to adding to the first tailings underflow component.

175. A high temperature paraffinic treatment process for treating a bitumen froth derived from an oil sands processing operation, the process comprising:
contacting the bitumen froth with a paraffinic solvent to form a mixture containing paraffin precipitated asphaltenes;
separating the mixture into a diluent bitumen component comprising bitumen and diluent solvent and a solvent diluent tailings component comprising heated water, fine solid material, precipitated asphaltenes, and residual bitumen and diluent solvent;
recovering substantially all of the diluent solvent from the diluted bitumen component in a solvent recovery apparatus to produce a solvent recovered bitumen component and recovered paraffinic solvent, the solvent recovery apparatus comprising a plurality of vessels configured in series with an associated condenser;
subjecting at least most of the solvent diluted tailings component to a solvent recovery separation to recover substantially all of the solvent in the solvent diluted tailings component as a separate recovered solvent component and produce a solvent recovered tailings component containing water, solids, and precipitated asphaltenes; and re-using the recovered paraffinic solvent from the diluted bitumen component and the solvent diluted tailing component as the paraffinic solvent in the step of contacting the bitumen froth with the paraffinic solvent.

176. A paraffinic solvent recovery process for recovering a paraffinic solvent from a diluted bitumen component derived from a high temperature paraffinic treatment of a bitumen froth, the paraffinic solvent recovery process comprising:
providing the diluted bitumen component into a solvent recovery apparatus, the solvent recovery apparatus comprising a plurality of vessels configured in series with an associated condenser;
recovering substantially all of the paraffinic solvent from the diluted bitumen component to produce a solvent recovered bitumen component and recovered paraffinic solvent; and re-using substantially all of the recovered paraffinic solvent from the diluted bitumen component as part of the paraffinic solvent for the treatment of the bitumen froth.

177. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes;
moderating a pressure of the diluted tailings component;
separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating comprising:
introducing the diluted tailings component into a solvent recovery apparatus following the moderating step;

discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component.

178. The process of claim 177, wherein the moderating is performed by a pressure regulator.

179. The process of claim 177, wherein the moderating is performed by a valve.

180. The process of claim 179, wherein the valve is a pressure valve.

181. The process of any one of claims 177 to 180, wherein the moderating of the pressure is provided upstream of the solvent recovery apparatus.

182. The process of any one of claims 177 to 180, wherein the moderating of the pressure is provided within the solvent recovery apparatus.

183. The process of any one of claims 177 to 182, comprising introducing a stream into the diluted tailings component after the step of separating the diluted bitumen froth and prior to the step of separating the diluted tailings component.

184. The process of any one of claims 177 to 182, comprising introducing a stream into the diluted tailings component after the step of separating the diluted bitumen froth and prior to the step of moderating the pressure of the diluted tailings component.

185. The process of claim 183 or 184, wherein the stream comprises water.

186. The process of any one of claims 183 to 185, wherein the stream comprises heated water.

187. The process of any one of claims 183 to 186, comprising subjecting the discharged solvent recovered tailings component to a thickening step to produce the stream in the form of a returned thickener overflow component.

188. The process of any one of claims 183 to 187, wherein the stream comprises a returned component derived from a separation unit and is provided so as to dilute the diluted tailings component to minimize plugging and to conserve heat energy contained in the returned component.

189. The process of any one of claims 183 to 189, wherein the stream is at a temperature close to operating temperature of the solvent recovery apparatus so as to avoid quenching of the diluted tailings component.

190. A high temperature paraffinic treatment process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth at a temperature between about 60°C and about 130°C, into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes;
separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating being performed in a two-unit solvent recovery apparatus, the separating comprising:
introducing the diluted tailings component into a first solvent recovery unit;
discharging from the first solvent recovery unit a first recovered solvent component and a first solvent recovered tailings component;
introducing the first solvent recovered tailings component into a second solvent recovery unit;
discharging from the second solvent recovery unit a second recovered solvent component and a second solvent recovered tailings component as a discharged solvent recovered tailings component.

191. The process of claim 190, wherein the paraffinic solvent comprises pentane.

192. The process of claim 191 or 191, wherein the paraffinic solvent comprises hexane.

193. The process of any one of claims 190 to 192, wherein the paraffinic solvent comprises heptane.

194. The process of any one of claims 190 to 193, wherein the paraffinic solvent comprises octane.

195. The process of any one of claims 190 to 194, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

196. The process of any one of claims 190 to 194, comprising the step of thickening at least a portion of the discharged solvent recovered tailings component.

197. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes;
separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating comprising:
introducing the diluted tailings component into a solvent recovery apparatus;
discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component;
recycling a portion of the discharged solvent recovered tailings component as a recycled solvent recovered tailings to combine with the diluted tailings component prior to introduction into the solvent recovery apparatus to regulate the temperature of the solvent recovery apparatus.

198. The process of claim 197, wherein the discharged solvent recovered tailings component is subjected to a thickening step to produce the recycled solvent recovered tailings component in the form of an overflow stream.

199. The process of claim 197 or 198, wherein the recycled solvent recovered tailings component is at a temperature close to operating temperature of the tailings solvent recovery apparatus.

200. The process of any one of claims 197 to 199, wherein the paraffinic solvent comprises pentane.

201. The process of any one of claims 197 to 200, wherein the paraffinic solvent comprises hexane.

202. The process of any one of claims 197 to 201, wherein the paraffinic solvent comprises heptane.

203. The process of any one of claims 197 to 202, wherein the paraffinic solvent comprises octane.

204. The process of any one of claims 197 to 203, wherein the operating temperature of the separation step is between about 60°C and about 130°C

205. The process of any one of claims 197 to 204, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

206. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes;
separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating comprising:
introducing the diluted tailings component into a solvent recovery apparatus;
discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component;

providing an internal flowrate through the solvent recovery apparatus to inhibit the formation of an asphaltene mat.

207. The process of claim 206, wherein the flowrate through the solvent recovery apparatus provides a downward flux in a bottom part of the solvent recovery apparatus.

208. The process of claim 206 or 207, wherein the paraffinic solvent comprises pentane.

209. The process of any one of claims 206 to 208, wherein the paraffinic solvent comprises hexane.

210. The process of any one of claims 206 to 209, wherein the paraffinic solvent comprises heptane.

211. The process of any one of claims 206 to 210, wherein the paraffinic solvent comprises octane.

212. The process of any one of claims 206 to 211, wherein the operating temperature of the separation step is between about 60°C and about 130°C

213. The process of any one of claims 206 to 212, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

214. The process of any one of claims 206 to 213, wherein the discharged solvent recovered tailings component is subjected to a thickening step to produce a thickened tailings component and an overflow stream.

215. The process of claim 214, wherein the overflow stream is recycled back into the solvent recovery apparatus.

216. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;

separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids, precipitated asphaltenes and foam;
transferring the diluted tailings component in-line from the separating step to a solvent recovery apparatus while breaking down the foam and discouraging plug flow of the diluted tailings component;
separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating comprising:
introducing the diluted tailings component into the solvent recovery apparatus;
discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component.

217. The process of claim 216, wherein the paraffinic solvent comprises pentane.

218. The process of claim 216 or 217, wherein the paraffinic solvent comprises hexane.

219. The process of any one of claims 216 to 218, wherein the paraffinic solvent comprises heptane.

220. The process of any one of claims 216 to 219, wherein the paraffinic solvent comprises octane.

221. The process of any one of claims 216 to 220, wherein the operating temperature of the separation step is between about 60°C and about 130°C

222. The process of any one of claims 216 to 221, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

223. The process of any one of claims 216 to 222, wherein the discharged solvent recovered tailings component is subjected to a thickening step to produce a thickened tailings component and an overflow stream.

224. The process of claim 223, wherein the overflow stream is recycled back into the diluted tailings component prior to introduction into the solvent recovery apparatus.

225. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids, precipitated asphaltenes and foam;
providing the diluted tailings component from the separating step to a solvent recovery apparatus at a separating step temperature sufficient to avoid pressure moderation of the diluted tailings component;
separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating comprising:
introducing the diluted tailings component into the solvent recovery apparatus;
discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component.

226. The process of claim 225, wherein the paraffinic solvent comprises pentane.

227. The process of claim 225 or 226, wherein the paraffinic solvent comprises hexane.

228. The process of any one of claims 225 to 227, wherein the paraffinic solvent comprises heptane.

229. The process of any one of claims 225 to 228, wherein the paraffinic solvent comprises octane.

230. The process of any one of claims 225 to 229, wherein the operating temperature of the separation step is between about 60°C and about 130°C

231. The process of any one of claims 225 to 230, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

232. The process of any one of claims 225 to 231, wherein the discharged solvent recovered tailings component is subjected to a thickening step to produce a thickened tailings component and an overflow stream.

233. The process of claim 232, wherein the overflow stream is recycled back into the diluted tailings component.

234. The process of claim 233, wherein the overflow stream is recycled back into the diluted tailings component prior to introduction into the solvent recovery apparatus.

235. The process of claim 233, wherein the overflow stream is recycled back into the diluted tailings component prior to introduction into the solvent recovery apparatus.

236. The process of claim 234 or 235, wherein the overflow stream is provided at a temperature close to an operating temperature of the solvent recovery apparatus.

237. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids, and paraffin-precipitated asphaltene flocs;
separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the separating comprising:
introducing the diluted tailings component into the solvent recovery apparatus and allowing liberation of some paraffin solvent therefrom;
providing conditioning in the solvent recovery apparatus to break up the paraffin-precipitated asphaltene flocs to encourage further liberation of paraffin solvent from the diluted tailings component;

discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component.

238. The process of claim 237, wherein the paraffinic solvent comprises pentane.

239. The process of claim 237 or 238, wherein the paraffinic solvent comprises hexane.

240. The process of any one of claims 237 to 239, wherein the paraffinic solvent comprises heptane.

241. The process of any one of claims 237 to 240, wherein the paraffinic solvent comprises octane.

242. The process of any one of claims 237 to 241, wherein the operating temperature of the separation step is between about 60°C and about 130°C

243. The process of any one of claims 237 to 242, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

244. The process of any one of claims 237 to 243, wherein the solvent recovery apparatus comprises at least two solvent recovery vessels arranged in series.

245. The process of claim 244, wherein the conditioning is provided in a lower section of each of the at least two solvent recovery vessels.

246. A process for treating an oil sands stream derived from a paraffinic froth treatment operation and containing paraffinic solvent and paraffin-precipitated asphaltene flocs, comprising:
ilntroducing the oil sands stream into a paraffinic solvent recovery apparatus and allowing liberation of some paraffin solvent therefrom;
providing conditioning in the solvent recovery apparatus to break up the paraffin-precipitated asphaltene flocs to encourage further liberation of paraffin solvent;
recovering the paraffinic solvent for re-use in the paraffinic froth treatment operation; and recovering a bottom component from the solvent recovery apparatus.

247. The process of claim 246, wherein the paraffinic solvent comprises pentane.

248. The process of claim 246 or 247, wherein the paraffinic solvent comprises hexane.

249. The process of any one of claims 246 to 248, wherein the paraffinic solvent comprises heptane.

250. The process of any one of claims 246 to 249, wherein the paraffinic solvent comprises octane.

251. The process of any one of claims 246 to 250, wherein the operating temperature of the separation step is between about 60°C and about 130°C

252. The process of any one of claims 246 to 251, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

253. The process of any one of claims 246 to 252, wherein the solvent recovery apparatus comprises at least two solvent recovery vessels arranged in series.

254. The process of claim 253, wherein conditioning is provided in a lower section of each of the at least two solvent recovery vessels.

255. A process for separating oil sands tailings comprising water, mineral solids and asphaltenes into multiple components, the process comprising:
introducing the oil sands tailings to a separation apparatus to induce separation and produce an upper component and a tailings underflow component, the tailings underflow component comprising the asphaltenes, wherein the separation apparatus comprises:
a sidewall defining a lower level and an upper level;
a feedwell for introducing the oil sands tailings;

a distributor apparatus for distributing the oil sands tailings upon entry into the separation apparatus;
at least one underflow outlet in communication with the lower level for withdrawing the tailings underflow component;
at least one upper outlet in communication with the upper level for withdrawing the upper component;
removing the upper component from the separation apparatus and discharging the tailings component from the separation apparatus.

256. The process of claim 255, wherein the distributor apparatus comprises a distributor plate.

257. The process of claim 255, wherein the distributor apparatus comprises a cone-shaped distributor plate.

258. The process of any one of claims 255 to 257, wherein the distributor apparatus is provided below the at least one upper outlet.

259. The process of any one of claims 255 to 258, wherein the distributor apparatus is provided so as to deflect the oil sands tailings outwardly as the oil sands tailings enters the separation apparatus.

260. The process of any one of claims 255 to 258, wherein the distributor apparatus is provided so as to deflect the oil sands tailings outwardly and downwardly as the oil sands tailings enters the separation apparatus.

261. The process of any one of claims 255 to 260, wherein the distributor apparatus consists of a single distributor plate.

262. The process of any one of claims 255 to 261, wherein the distributor apparatus is provided in a central location within the separation apparatus.

263. The process of any one of claims 255 to 262, wherein the distributor apparatus is oriented to deflect the oil sands tailings toward the at least one upper outlet.

264. The process of any one of claims 255 to 263, wherein the distributor apparatus is provided below the feedwell and above the at least one underflow outlet such that the oil sands tailings distribute over the distributor apparatus and separate such that the tailings underflow component flows around edges of the distributor apparatus and develops downwardly toward the lower level.

265. A process for treating a solvent recovered tailings component, the process comprising:
adding a paraffinic solvent to a bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes;
separating the diluted tailings component into a recovered solvent component and the solvent recovered tailings component, the separating comprising:
introducing the diluted tailings component into a solvent recovery apparatus;
discharging the solvent recovered tailings component from the solvent recovery apparatus;
introducing the solvent recovered tailings component to a thickener comprising:
a distributor apparatus for distributing the oil sands tailings upon entry into the thickener;
at least one underflow outlet in communication with the lower level for withdrawing the tailings underflow component; and at least one overflow outlet in communication with the upper level for withdrawing the overflow component.

266. The process of claim 265, wherein the distributor apparatus comprises a distributor plate.

267. The process of claim 265 or 266, wherein the distributor apparatus comprises a cone-shaped distributor plate.

268. The process of any one of claims 265 to 267, wherein the distributor apparatus is provided below the at least one overflow outlet.

269. The process of any one of claims 265 to 268, wherein the distributor apparatus is provided so as to deflect the solvent recovered tailings component outwardly as the solvent recovered tailings component enters the thickener.

270. The process of any one of claims 265 to 269, wherein the distributor apparatus is provided so as to deflect the solvent recovered tailings component outwardly and downwardly as the solvent recovered tailings component enters the thickener.

271. The process of any one of claims 265 to 270, wherein the distributor apparatus consists of a single distributor plate.

272. The process of any one of claims 265 to 271, wherein the distributor apparatus is provided in a central location within the thickener.

273. The process of any one of claims 265 to 272, wherein the distributor apparatus is oriented to deflect the solvent recovered tailings component toward the at least one overflow outlet.

274. The process of any one of claims 265 to 273, wherein the distributor apparatus is provided below a feedwell for introducing the solvent recovered tailings component and above the at least one underflow outlet such that the solvent recovered tailings component distributes over the distributor apparatus and separates such that the tailings underflow component flows around edges of the distributor apparatus and develops downwardly toward the lower level.

275. The process of any one of claims 265 to 274, wherein the paraffinic solvent comprises pentane.

276. The process of any one of claims 265 to 275, wherein the paraffinic solvent comprises hexane.

277. The process of any one of claims 265 to 276, wherein the paraffinic solvent comprises heptane.

278. The process of any one of claims 265 to 277, wherein the paraffinic solvent comprises octane.

279. The process of any one of claims 265 to 278, wherein the operating temperature of the separation step is between about 60°C and about 130°C

280. The process of any one of claims 265 to 279, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

281. A process for conserving heat energy contained in a returned overflow component by re-using the returned overflow component in an oil sands processing operation, comprising:
subjecting an oil sands tailings component to gravity separation to produce an underflow tailings component and an overflow component;
recycling the overflow component to equipment of the oil sands processing operation.

282. The process of claim 281, wherein the equipment is selected from the group consisting of a primary settling vessel for treating an oil sand slurry, a separator apparatus for treating a bitumen froth with a paraffinic solvent, and a flotation cell for treating a middlings stream derived from the primary settling vessel.

283. The process of claim 281, wherein the equipment comprises a primary settling vessel for treating an oil sands slurry.

284. The process of claim 281, wherein the equipment comprises a separator apparatus for treating a bitumen froth with a paraffinic solvent.

285. The process of claim 281, wherein the equipment comprises a flotation cell for treating a middlings stream derived from a primary settling vessel for treating an oil sands slurry.

286. A process for re-using heat energy in an oil sands processing operation comprising:
separating an oil sands slurry comprising heated water, particulate coarse and fine solid material, and bitumen and asphaltenes into an overflow bitumen froth stream, a middlings stream and an underflow tailings stream;
subjecting the overflow bitumen froth stream to a paraffinic froth treatment operation;
recovering heat energy from the middlings stream;
recycling the heat energy to the paraffinic froth treatment operation.

287. The process of claim 286, wherein the heat energy recovered from the middlings stream is contained in an overflow component derived from a separator.

288. The process of claim 286, wherein the heat energy recovered from the middlings stream is contained in an unclarified overflow component derived from a thickener.

289. The process of any one of claims 286 to 288, wherein the paraffinic froth treatment operation uses paraffinic solvent having a carbon chain length from C5 to C8.

290. The process claim 289, wherein the paraffinic solvent comprises pentane.

291. The process of claim 289 or 290, wherein the paraffinic solvent comprises hexane.

292. The process of any one of claims 289 to 291, wherein the paraffinic solvent comprises heptane.

293. The process of any one of claims 289 to 292, wherein the paraffinic solvent comprises octane.

294. The process of any one of claims 286 to 293, wherein the operating temperature of the paraffinic froth treatment operation is between about 60°C and about 130°C

295. The process of any one of claims 286 to 294, wherein the operating temperature of the paraffinic froth treatment operation is between about 70°C and about 90°C.

296. A process for re-using water in an oil sands processing operation comprising:
separating an oil sands slurry comprising heated water, particulate coarse and fine solid material, and bitumen and asphaltenes into an overflow bitumen froth stream, a middlings stream and an underflow tailings stream;
subjecting the overflow bitumen froth stream to a paraffinic froth treatment operation;
recovering from the middlings stream an overflow stream;
recycling the overflow stream to the paraffinic froth treatment operation.

297. The process of claim 296, wherein the overflow stream comprises an unclarified overflow component derived from a thickener.

298. The process of any one of claims 296 to 297, wherein the paraffinic froth treatment operation uses paraffinic solvent having a carbon chain length from C5 to C8.

299. The process claim 298, wherein the paraffinic solvent comprises pentane.

300. The process of claim 298 or 299, wherein the paraffinic solvent comprises hexane.

301. The process of any one of claims 298 to 300, wherein the paraffinic solvent comprises heptane.

302. The process of any one of claims 298 to 301, wherein the paraffinic solvent comprises octane.

303. The process of any one of claims 296 to 300, wherein the operating temperature of the paraffinic froth treatment operation is between about 60°C and about 130°C

304. The process of any one of claims 296 to 300, wherein the operating temperature of the paraffinic froth treatment operation is between about 70°C and about 90°C.

305. A process for re-using water in an oil sands processing operation comprising:
subjecting an oil sands slurry comprising heated water, particulate coarse and fine solid material, and bitumen and asphaltenes to an extraction operation comprising separating the oil sands slurry into an overflow bitumen froth stream, a middlings stream and an underflow tailings stream;
recovering from the middlings stream a clarified overflow stream;
recycling the clarified overflow stream to the extraction operation.

306. The process of claim 305, wherein the clarified overflow stream is directly used as recycle water for the extraction operation.

307. The process of claim 305, wherein the clarified overflow stream is directly used in a heat exchanger and avoids fouling therein.

308. The process of claim 307, wherein re-using the clarified overflow stream in the heat exchanger enables recovery of heat energy from the clarified overflow stream.

309. The process of any one of claims 305 to 308, wherein the clarified overflow stream is recycled at least in part to a paraffinic froth treatment operation.

310. The process of claim 309, wherein the paraffinic froth treatment operation uses paraffinic solvent having a carbon chain length from C5 to C8.

311. The process claim 310, wherein the paraffinic solvent comprises pentane.

312. The process of claim 310 or 311, wherein the paraffinic solvent comprises hexane.

313. The process of any one of claims 310 to 312, wherein the paraffinic solvent comprises heptane.

314. The process of any one of claims 310 to 313, wherein the paraffinic solvent comprises octane.

315. The process of any one of claims 309 to 314, wherein the operating temperature of the paraffinic froth treatment operation is between about 60°C and about 130°C

316. The process of any one of claims 309 to 315, wherein the operating temperature of the paraffinic froth treatment operation is between about 70°C and about 90°C.

317. A process for treating an oil sand slurry comprising heated water, particulate coarse and fine solid material, and bitumen and asphaltenes, the process comprising:
separating the oil sands slurry into an overflow bitumen froth stream, a middlings stream and an underflow coarse tailings stream;
subjecting the overflow bitumen froth stream to a paraffinic froth treatment operation comprising:
contacting the overflow bitumen froth stream with a paraffinic solvent to form a mixture containing precipitated asphaltenes;
separating the mixture into a diluent bitumen component and a solvent diluent tailings component;
recovering the paraffinic solvent from the diluted bitumen component;
subjecting the solvent diluted tailings component to a solvent recovery separation to recover the paraffinic solvent and produce a solvent recovered tailings component; and subjecting the solvent recovered tailings component to a separation step to produce an overflow stream and a paraffinic froth treatment fine tailings component;
separating the middlings stream into a secondary bitumen froth stream and a final middlings fine tailings component;
combining the paraffinic froth treatment fine tailings component with the final middlings fine tailings component to produce an combined fine tailings.

318. The process of claim 317, wherein the separating of the middlings stream into the secondary bitumen froth stream and the final middlings tailings component comprises:
subjecting the middlings stream to a secondary recovery step to produce a secondary bitumen froth stream and middlings tailings;
separating the middlings tailings into a solid material stream and a fine tailings stream;
thickening the fine tailings stream to produce an overflow component and an underflow component as the final middlings tailings component.

319. The process of claim 318, wherein the solid material stream derived from the middlings tailings is combined with the underflow coarse tailings stream to produce a combined coarse tailings.

320. The process of claim 319, wherein the combined coarse tailings are used to construct a fine tailings containment facility and the combined fine tailings are disposed in the fine tailings containment facility.

321. The process of claim 320, wherein the fine tailings containment facility comprises berms or dykes.

322. A process for controlling relative proportions of multiple components withdrawn from an oil sands tailings thickener, the multiple components comprising an underflow component, an unclarified overflow component and a clarified overflow component, the process comprising controlling a volumetric flowrate of a tailings stream entering the thickener, controlling a volumetric flowrate of the underflow component and controlling a volumetric flowrate of the clarified overflow component.

323. The process of claim 322, wherein unclarified overflow component is withdrawn from the separation apparatus above the clarified overflow component.

324. A process for controlling relative proportions of multiple components withdrawn from an oil sands tailings separation apparatus for separating a fine tailings stream containing water, mineral solids and paraffin-precipitated asphaltenes, the multiple components comprising an underflow component, a first overflow component and a second overflow component, the process comprising controlling a volumetric flowrate of the fine tailings stream entering the oil sands tailings separation apparatus, controlling a volumetric flowrate of the underflow component and controlling a volumetric flowrate of the first overflow component.

325. The process of claim 324, wherein first overflow component is withdrawn from the separation apparatus above the second overflow component.

326. A process for controlling relative proportions of multiple components withdrawn from an oil sands tailings separation apparatus for separating a fine tailings stream containing water, mineral solids and asphaltenes, the multiple components comprising an underflow component, a first upper component and a second upper component, the process comprising controlling a volumetric flowrate of the fine tailings stream entering the oil sands tailings separation apparatus, controlling a volumetric flowrate of the underflow component and controlling a volumetric flowrate of the first upper component.

327. The process of claim 326, wherein first upper component is withdrawn from the separation apparatus above the second upper component.

328. In a process for treating a bitumen froth, wherein the process comprises a paraffinic solvent adding step for adding a paraffinic solvent to the bitumen froth to provide a diluted bitumen froth, wherein the process comprises a separating step for separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes, and wherein the process comprises a solvent recovering step for separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the improvement which comprises:
introducing the diluted tailings component into a solvent recovery apparatus following the separating step;
discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component; and thickening at least a portion of the discharged solvent recovered tailings component to produce a thickener underflow component and a thickener overflow component.

329. The process of claim 328, wherein the separating step is performed in a separator apparatus, further comprising the step of returning a portion of the thickener overflow component to the separator apparatus as a returned thickener overflow component.

330. The process of claim 329, wherein the separator apparatus comprises a plurality of separator units configured in series and wherein the returned thickener overflow component is distributed to one or more of the separator units.

331. The process of any one of claims 328 to 330, further comprising the separating step, wherein the separating step comprises the following steps:
(I) separating the bitumen froth into a first separating stage overflow component and a first separating stage underflow component;
(ii) adding a paraffinic solvent to the first separating stage underflow component to provide a diluted first separating stage underflow component;
(iii) separating the diluted first separating stage underflow component into a second separating stage overflow component and a second separating stage underflow component, wherein the second separating stage underflow component comprises the diluted tailings component;

(iv) returning the second separating step overflow component to the first separating step so that the second separating step overflow component mixes with the bitumen froth to provide the diluted bitumen froth.

332. The process of claim 331, further comprising the step of returning a portion of the thickener overflow component to the separating step as a returned thickener overflow component.

333. The process of claim 332, wherein the returned thickener overflow component is returned to one of the first separating step and the second separating step.

334. The process of claim 332, wherein the returned thickener overflow component is returned to both of the first separating step and the second separating step.

335. The process of any one of claims 331 to 334, wherein the first separating step is performed at a temperature which is lower than a temperature at which the second separating step is performed.

336. The process of any one of claims 331 to 334, wherein the first separating step is performed at a temperature and wherein the second separating step is performed at a temperature, further comprising the step of providing a heat input to the second separating step in order to control the temperature of the first separating step and the temperature of the second separating step.

337. An apparatus for treating a bitumen froth comprising:
a paraffinic solvent recovery apparatus for separating a diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the diluted tailings component being recovered from the bitumen froth and comprising water, mineral solids and residual bitumen and paraffin-precipitated asphaltenes;
a discharge outlet for discharging the solvent recovered tailings component from the solvent recovery apparatus as a discharged solvent recovered tailings component; and a thickener vessel associated with the solvent recovery apparatus for thickening at least a portion of the discharged solvent recovered tailings component to produce a thickener underflow component and a thickener overflow component.

338. The apparatus of claim 337, wherein the solvent recovery apparatus is associated with a separator apparatus for separating the bitumen froth into a diluted bitumen component and the diluted tailings component, further comprising a thickener return line for returning at least a portion of the thickener overflow component to the separator apparatus as a returned thickener overflow component.

339. A process for treating oil sands tailings containing water, mineral solids and bitumen comprising asphaltenes, comprising the following steps:
introducing the tailings into a thickener vessel;
withdrawing an underflow component from a lower level of the thickener vessel;
withdrawing a clarified overflow component from an intermediate level of the thickener vessel; and withdrawing an unclarified overflow component from an upper level of the thickener vessel.

340. The process of claim 339, wherein the thickener vessel comprises a sidewall and wherein the tailings are introduced into the thickener vessel at a location which is in spaced relation to the sidewall.

341. The process of claim 340, wherein the sidewall defines a thickener area and wherein the tailings are introduced into the thickener vessel at a central location within the thickener area.

342. The process of claim 341, wherein the tailings are introduced into the thickener vessel at the intermediate level of the thickener vessel.

343. The process of claim 342, further comprising the step of distributing the tailings within the thickener vessel after they are introduced into the thickener vessel.

344. The process of claim 343, wherein the distributing step is comprised of introducing the tailings into the thickener vessel so that they contact a distributor apparatus located within the thickener vessel.

345. The process of any one of claims 340 to 344, wherein the clarified overflow component is withdrawn from the thickener vessel adjacent to the sidewall of the thickener vessel.

346. The process of any one of claims 340 to 345, wherein the unclarified overflow component is withdrawn from the thickener vessel adjacent to the sidewall of the thickener vessel.

347. The process of any one of claims 340 to 345, further comprising the step, prior to withdrawing the unclarified overflow component from the thickener vessel, of collecting the unclarified overflow component in a launder adjacent to the sidewall of the thickener vessel.

348. The process of claim 347, wherein the unclarified overflow component is withdrawn from the thickener vessel adjacent to the sidewall of the thickener vessel.

349. The process of claim 348, further comprising the step, prior to withdrawing the unclarified overflow component from the thickener vessel, of collecting the unclarified overflow component in a launder adjacent to the sidewall of the thickener vessel.

350. The process of any one of claims 340 to 349, further comprising the step of adding a flocculant to the tailings.

351. The process of any one of claims 340 to 350, further comprising the step of passing a gas upwards through the tailings within the thickener vessel.

352. The process of claim 351, wherein the gas is passed upwards through the tailings between the sidewall and the central location within the thickener area so that the clarified overflow component may pass through the gas before being withdrawn from the thickener vessel.

353. The process of claim 352, wherein the gas comprises air.

354. The process of any one of claims 339 to 353, wherein the clarified overflow component encounters a baffle arrangement located within the thickener vessel in order to still the clarified overflow component before it is withdrawn from the thickener vessel.

355. A thickener vessel comprising:
a sidewall defining a lower level of the thickener vessel, an intermediate level of the thickener vessel and an upper level of the thickener vessel;
a feedwell for introducing tailings into the thickener vessel;
at least one underflow outlet in communication with the lower level of the thickener vessel for withdrawing an underflow component from the thickener vessel;
at least one clarified overflow outlet in communication with the intermediate level of the thickener vessel for withdrawing a clarified overflow component from the thickener vessel; and at least one unclarified overflow outlet in communication with the upper level of the thickener vessel for withdrawing an unclarified overflow component from the thickener vessel.

356. The thickener vessel of claim 355, wherein the feedwell is located in spaced relation to the sidewall.

357. The thickener vessel of claim 356, wherein the feedwell extends from the upper level of the thickener vessel to the intermediate level of the thickener vessel so that the tailings are introduced into the thickener vessel at the intermediate level of the thickener vessel.

358. The thickener vessel of claim 357, wherein the sidewall defines a thickener area and wherein the feedwell is located at a central location within the thickener area.

359. The thickener vessel of claim 358, wherein the clarified overflow outlet is located adjacent to the sidewall.

360. The thickener vessel of claim 358, wherein the unclarified overflow outlet is located adjacent to the sidewall.

361. The thickener vessel of claim 360, further comprising a launder located at the upper level of the thickener vessel and adjacent to the sidewall for collecting the unclarified overflow component, wherein the unclarified overflow outlet is in communication with the launder.

362. The thickener vessel of claim 361, wherein the unclarified overflow outlet is located adjacent to the sidewall.

363. The thickener vessel of claim 362, further comprising a launder located at the upper level of the thickener vessel and adjacent to the sidewall for collecting the unclarified overflow component, wherein the unclarified overflow outlet is in communication with the launder.

364. The thickener vessel of claim 359, further comprising a sparge apparatus for passing a gas upwards through the tailings within the thickener vessel.

365. The thickener vessel of claim 364, wherein the sparge apparatus is located within the thickener vessel between the sidewall and the feedwell.

366. The thickener vessel of claim 465, wherein the sparge apparatus is located within the thickener vessel between the clarified overflow outlet and the feedwell so that the clarified overflow component may pass through the gas before being withdrawn from the thickener vessel.

367. The thickener vessel of claim 364, wherein a plurality of clarified overflow outlets are distributed around the sidewall.

368. The thickener vessel of claim 367, wherein the sparge apparatus is located within the thickener vessel between the plurality of clarified overflow outlets and the feedwell so that the clarified overflow component passes through the gas before being withdrawn from the thickener vessel.

369. The thickener vessel of 365 to 368, further comprising a baffle arrangement located within the thickener vessel between the sparge apparatus and the clarified overflow outlet, for stilling the clarified overflow component before it is withdrawn from the thickener vessel.

370. The thickener vessel of any one of claims 355 to 369, further comprising a distributor apparatus for distributing the tailings within the thickener vessel after they are introduced into the thickener vessel.

371. The thickener vessel of claim 370, wherein the distributor apparatus comprises a distributor plate.

372. An apparatus for treating oil sands tailings containing water, mineral solids and bitumen comprising asphaltenes, the apparatus comprising:
walls defining a chamber having a lower level and an upper level;
a feedwell for introducing the oil sands tailings into the chamber;
at least one underflow outlet in communication with the lower level for withdrawing an underflow component comprising mineral solids and water;
at least one unclarified overflow outlet in communication with the upper level for withdrawing an unclarified overflow component comprising the bitumen and a sparge apparatus within the chamber for providing gas bubbles therein.

373. The apparatus of claim 372, wherein the walls further define an intermediate level and the apparatus further comprises at least one clarified overflow outlet in communication with the intermediate level for withdrawing a clarified overflow component comprising heated water.

374. The apparatus of claim 373, wherein the sparge apparatus is located between the at least one clarified overflow outlets and the feedwell.

375. The apparatus of claim 374, wherein the feedwell is located in spaced relation to the sidewall.

376. The apparatus of any one of claims 373 to 375, wherein the feedwell extends from the upper level to the intermediate level so that the oil sands tailings are introduced into the chamber at the intermediate level.

377. The apparatus of claim 376, wherein the sidewall defines an area and wherein the feedwell is located at a central location within the area.

378. The apparatus of any one of claims 373 to 377, wherein the clarified overflow outlet is located adjacent to the sidewall.

379. The apparatus of any one of claims 373 to 378, wherein the unclarified overflow outlet is located adjacent to the sidewall.

380. The apparatus of any one of claims 373 to 379, comprising a launder located at the upper level and adjacent to the sidewall for collecting the unclarified overflow component, wherein the unclarified overflow outlet is in communication with the launder.

381. The apparatus of any one of claims 373 to 380, wherein the at least one clarified overflow outlet comprises a plurality of clarified overflow outlets that are distributed around the sidewall.

382. The apparatus of claim 381, wherein the sparge apparatus is located within the thickener vessel between the plurality of clarified overflow outlets and the feedwell so that the clarified overflow component passes through the gas before being withdrawn from the thickener vessel.

383. The apparatus of any one of claims 373 to 382, comprising a baffle arrangement located within the thickener vessel between the sparge apparatus and the clarified overflow outlet, for stilling the clarified overflow component before it is withdrawn from the thickener vessel.

384. The apparatus of any one of claims 373 to 383, further comprising a distributor apparatus for distributing the tailings within the chamber after they are introduced.

385. The apparatus of claim 384, wherein the distributor apparatus comprises a distributor plate.

386. A process for treating oil sands tailings containing water, mineral solids and bitumen comprising asphaltenes, comprising the following steps:
introducing the tailings into a thickener vessel;
withdrawing the underflow component comprising mineral solids and water from a lower level of the thickener vessel;
withdrawing an unclarified overflow component comprising the bitumen from an upper level of the thickener vessel; and passing a gas upwards through the tailings within the thickener vessel.

387. The process of claim 386, comprising withdrawing a clarified overflow component from an intermediate level of the thickener vessel.

388. The process of claim 387, wherein the thickener vessel comprises a sidewall and wherein the tailings are introduced into the thickener vessel at a location which is in spaced relation to the sidewall.

389. The process of claim 388, wherein the sidewall defines a thickener area and wherein the tailings are introduced into the thickener vessel at a central location within the thickener area.

390. The process of claim 389, wherein the tailings are introduced into the thickener vessel at the intermediate level of the thickener vessel.

391. The process of claim 390, further comprising the step of distributing the tailings within the thickener vessel after they are introduced into the thickener vessel.

392. The process of claim 391, wherein the distributing step is comprised of introducing the tailings into the thickener vessel so that they contact a distributor apparatus located within the thickener vessel.

393. The process of any one of claims 386 to 392, wherein the clarified overflow component is withdrawn from the thickener vessel adjacent to the sidewall of the thickener vessel.

394. The process of any one of claims 386 to 393, wherein the unclarified overflow component is withdrawn from the thickener vessel adjacent to the sidewall of the thickener vessel.

395. The process of any one of claims 386 to 394, further comprising the step, prior to withdrawing the unclarified overflow component from the thickener vessel, of collecting the unclarified overflow component in a launder adjacent to the sidewall of the thickener vessel.

396. The process of claim 395, wherein the unclarified overflow component is withdrawn from the thickener vessel adjacent to the sidewall of the thickener vessel.

397. The process of claim 396, further comprising the step, prior to withdrawing the unclarified overflow component from the thickener vessel, of collecting the unclarified overflow component in a launder adjacent to the sidewall of the thickener vessel.

398. The process of any one of claims 386 to 397, further comprising the step of adding a flocculant to the tailings.

399. The process of claim 398, wherein the flocculant is added to the tailings within the thickener vessel.

400. The process of claim 399, wherein the flocculant is premixed with the tailings prior to entering the thickener vessel.

401. The process of claim 400, wherein the flocculant is separately added to the thickener vessel at the feedwell.

402. The process of any one of claims 386 to 401, wherein the gas is passed upwards through the tailings between the sidewall and the central location within the thickener area so that the clarified overflow component may pass through the gas before being withdrawn from the thickener vessel.

403. The process of claim 402, wherein the gas comprises air.

404. The process of any one of claims 386 to 403, wherein the clarified overflow component encounters a baffle arrangement located within the thickener vessel in order to still the clarified overflow component before it is withdrawn from the thickener vessel.

405. The process of any one of claims 386 to 404, wherein the oil sand tailings are derived from a bitumen froth treatment comprising:
a solvent adding step for adding a paraffinic solvent to a bitumen froth to provide a diluted bitumen froth;
a separating step for separating the diluted bitumen froth into a diluted bitumen component comprising bitumen and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes, and a solvent recovering step for separating the diluted tailings component into a recovered solvent component and a solvent recovered tailings component, the solvent recovered tailings component being used as the oil sand tailings.

406. The process of claim 405, wherein the paraffinic solvent has a carbon chain length from C5 to C8.

407. The process claim 406, wherein the paraffinic solvent comprises pentane.

408. The process of claim 406 or 407, wherein the paraffinic solvent comprises hexane.

409. The process of any one of claims 406 to 408, wherein the paraffinic solvent comprises heptane.

410. The process of any one of claims 406 to 409, wherein the paraffinic solvent comprises octane.

411. The process of any one of claims 406 to 410, wherein the operating temperature of the paraffinic froth treatment operation is between about 60°C and about 130°C.

412. The process of claim 176, wherein the solvent recovered bitumen component is stored.

413. The process of claim 176, wherein the solvent recovered bitumen component is transported.

414. The process of claim 176, wherein the solvent recovered bitumen component is transported for upgrading.

415. The process of any one of claims 225 to 236, wherein the step of separating the diluted bitumen froth is performed in a two-unit separation apparatus, and comprises the sub-steps of:
feeding the diluted bitumen froth into a first separation unit and producing a first diluted bitumen overflow component as the diluted bitumen component and a first tailings underflow component that are removed from the first separation unit;
adding paraffinic solvent to the first tailings underflow component to produce a first diluted tailings component; and feeding the first diluted tailings component to a second separation unit and producing a second diluted bitumen overflow component and a second tailings underflow component as the solvent diluent tailings component that are removed from the second separation unit.

416. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent containing stream to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes;
adding a dilution stream into the diluted tailings component to produce a tailings solvent recovery feed stream;
providing the tailings solvent recovery feed stream to a tailings solvent recovery apparatus; and separating the tailings solvent recovery feed stream into a recovered solvent component and a solvent recovered tailings component.

417. The process of claim 416, wherein the dilution stream comprises an aqueous stream.

418. The process of claim 416 or 417, wherein the dilution stream is derived from a downstream separation unit.

419. The process of claim 418, wherein the downstream separation unit comprises a thickening unit and the dilution stream is an overflow component of the thickening unit.

420. The process of any one of claims 416 to 419, wherein the paraffinic solvent comprises pentane.

421. The process of any one of claims 416 to 420, wherein the paraffinic solvent comprises hexane.

422. The process of any one of claims 416 to 421, wherein the paraffinic solvent comprises heptane.

423. The process of any one of claims 416 to 422, wherein the paraffinic solvent comprises octane.

424. The process of any one of claims 416 to 423, wherein the operating temperature of the separation step is between about 60°C and about 130°C

425. The process of any one of claims 416 to 424, wherein the operating temperature of the separation step is between about 70°C and about 90°C.

426. The process of any one of claims 416 to 425, comprising pumping the dilution stream into the diluted tailings component.

427. The process of any one of claims 416 to 426, wherein the dilution stream is added to the diluted tailings component proximate to a bottom outlet of a separator that produces the diluted tailings component.

428. The process of any one of claims 416 to 427, wherein the step of separating the diluted bitumen froth is performed in a two-unit separation apparatus, and comprises the sub-steps of:
feeding the diluted bitumen froth into a first separation unit and producing a first diluted bitumen overflow component as the diluted bitumen component and a first tailings underflow component that are removed from the first separation unit;
adding paraffinic solvent to the first tailings underflow component to produce a first diluted tailings component; and feeding the first diluted tailings component to a second separation unit and producing a second diluted bitumen overflow component and a second tailings underflow component as the solvent diluent tailings component that are removed from the second separation unit.

429. The process of claim 428, wherein the dilution stream is added to the second tailings underflow component proximate a bottom outlet of the second separation unit.

430. The process of claim 428, wherein the dilution stream is added to the second tailings underflow component in the tailings solvent recovery apparatus.

431. The process of any one of claims 416 to 430, comprising providing the dilution stream at a temperature close to an operating temperature of the tailings solvent recovery apparatus.

432. The process of any one of claims 416 to 430, comprising providing the dilution stream at a temperature sufficient to avoid quenching of the dilute tailings component.

433. The process of any one of claims 416 to 430, comprising providing the dilution stream at a temperature sufficient to avoid interference with operation of the tailings solvent recovery apparatus.

434. The process of any one of claims 416 to 430, wherein the tailings solvent recovery apparatus comprises two tailings solvent recovery units provided in series.

435. A process for treating a bitumen froth, comprising:
adding a paraffinic solvent containing stream to the bitumen froth to provide a diluted bitumen froth;
separating the diluted bitumen froth into a diluted bitumen component and a diluted tailings component comprising water, particulate solids and precipitated asphaltenes;
diluting the diluted tailings component to produce a tailings solvent recovery feed stream;
providing the tailings solvent recovery feed stream to a tailings solvent recovery apparatus; and separating the tailings solvent recovery feed stream into a recovered solvent component and a solvent recovered tailings component.