CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the priority benefit of United States Provisional Application 63/310,442 filed on February 15, 2022, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

[0001] The present invention relates to removing an organic solvent from a mixture comprising the organic solvent, bitumen and mineral solids comprising sand and clay particles. The mixture may be a gangue produced by a solvent-based process for extraction of bitumen from oil sands ore.

BACKGROUND OF THE INVENTION

[0002] The oil reserve in Canada is the third largest in the world. The majority of oil production takes place in the province of Alberta. Two commercial processes are used to extract bitumen from oil sands ores, and they both involve the use of water but at different temperatures. One is through the surface mining while the other is steam-assisted gravity drainage (SAGD) for bitumen deposited deep in the ground. In the surface mining process, warm water at about 50 °C is used to extract bitumen from the ores. This process consumes a significant amount of energy to heat the water and produces tailings which are slurries that contain solid particles, mostly made up of sand and clay, with sizes ranging from a few microns to a few hundred microns. In general, newly produced tailings contain about 30 wt% solids and 70 wt% water, and solid particles with sizes less than 45 microns, mostly made up of clay, do not settle even after several decades.

[0003] Owing to the worsening of the tailing ponds issue, recently, researchers have reexamined the possibility of using an organic solvent at room temperature to extract bitumen. Cyclohexane has been demonstrated to be a suitable organic solvent for the non-aqueous extraction of bitumen. The major advantage of a solvent-based extraction process is that it is carried out at room temperature. However, this process produces waste materials (gangue) that contain small amount of water (3 to 4 wt% which is connately present in the ores), unrecovered bitumen, and residual extraction solvent. To commercialize such an extraction process, reliable methods that minimize its negative environmental impacts must be developed to recover and possibly reuse the residual solvent in the gangue.

[0004] Currently, example recovery methods of solvents from oil sand gangue include airdrying methods. Air drying methods require minimal energy, but are slow processes. Given that typical gangue comprises mainly sand and clay particles (80 to 90 wt%), conventional conduct! on/conventi on heating is not feasible as heating the solids cannot be avoided, and this would make the non-aqueous extraction process energy inefficient.

[0005] There remains a need in the art for energy efficient methods for removing an organic solvent, such as cyclohexane, from an oil sands gangue.

SUMMARY OF THE INVENTION

[0006] A method is provided that uses microwave heating to remove a residual organic solvent that is present in gangue produced by solvent-based process for extraction of bitumen from oil sands ore. The method may have useful applications for removing organic solvents from other mixtures comprising organic solvent, bitumen and mineral solids comprising sand and clay particles. A non-limiting example of an organic solvent that can be removed using this method is cyclohexane. Since the normal boiling point of cyclohexane (81 °C) is lower than that of water (100 °C), it is believed that the thermal energy obtained by the water molecules during the microwave heating but before its vaporization is transferred to nearby cyclohexane molecules, thereby facilitating the vaporization of cyclohexane.

[0007] In one aspect, the present invention comprises a method for removing an organic solvent from a mixture comprising the organic solvent, bitumen and mineral solids comprising sand and clay particles. The method comprises the steps of: (a) if necessary, adding water to the mixture so that the mixture has a water content greater than 0 wt% by weight of the mineral solids; and (b) exposing the mixture with the water content to microwaves to heat the mixture and thereby vaporize at least a portion of the organic solvent from the mixture. Additional aspects of embodiments of the method are described below.

[0008] In another aspect, the present invention comprises a system for removing an organic solvent from a mixture the organic solvent, bitumen and mineral solids comprising sand and clay particles. The system comprises: (a) a container for holding or supporting the mixture; (b) a microwave source for emitting microwaves at the mixture in the container; and (c) a gas source for creating a flow of gas past the mixture to carry vaporized organic solvent away from the mixture. Additional aspects of embodiments of the system are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the drawings, like elements may be assigned like reference numerals. The drawings are not necessarily to scale, with the emphasis instead placed upon the principles of the present invention. Additionally, each of the embodiments depicted are but one of a number of possible arrangements utilizing the fundamental concepts of the present invention.

[0010] Fig. 1 A shows an example embodiment of a system for microwave heating of an oil sands gangue, used in an example of a method of the present invention.

[0011] Fig. IB shows another example embodiment of a system for microwave heating of an oil sands gangue, used in another example of a method of the present invention.

[0012] Fig. 1C shows an example embodiment for continuous processing of oil sands gangue.

[0013] Figs. 2A to 2C collectively show a method to determine the residual cyclohexane in reconstituted gangue samples using gas chromatography analysis. Fig. 2A shows addition of toluene to a reconstituted gangue sample. Fig. 2B shows mixing of the toluene and reconstituted gangue sample, followed by a rest period. Fig. 2C shows collection of a supernatant liquid from the mixture, and subjecting the collected supernatant liquid to gas chromatography (GC) analysis to determine its cyclohexane content. [0014] Fig. 3 shows Table 1 summarizing compositions of prepared samples of reconstituted oil sands gangue.

[0015] Fig. 4 is a graph of temperatures of samples of Table 1 while subjected to microwave heating for an entire 5000 second time span in a first example of a method of the present invention.

[0016] Fig. 5 is a graph of temperatures of samples of Table 1 while subjected to microwave heating for the first 800 seconds of microwave heating in an example of a method of the present invention.

[0017] Fig. 6 is a graph of temperature of reconstituted oil sands gangue samples having different water contents during microwave heating in an example of a method of the present invention.

[0018] Fig. 7 shows Table 2 summarizing the mean and standard deviation data for volatile mass loss for reconstituted oil sands gangue samples subjected to microwave heating an example of a method of the present invention.

[0019] Fig. 8 is a chart of volatile mass loss of a reconstituted oil sands gangue sample having a 6 wt% water content during microwave heating in an example of a method of the present invention.

[0020] Fig. 9 shows Table 3 summarizing mean and standard deviation data for residual cyclohexane contents (ppm) as determined by gas chromatography, for different reconstituted oil sands gangue samples subjected to microwave heating, in an example of a method of the present invention.

[0021] Fig. 10 shows Table 4 summarizing parameters measured to calculate residual cyclone hexane content and the calculated residual cyclohexane content for reconstituted oil sands gangue samples subjected to microwave heating, in an example of a method of the present invention.

[0022] Fig. 11 A shows an example method for microwave heating of an oil sands gangue. [0023] Fig. 1 IB shows another example method for microwave heating of an oil sands gangue.

[0024] Fig. 11C shows another example method for cyclical recovery and re-use of organic solvent.

[0025] Fig. 12 shows a simplified hardware block diagram for an example controller.

DETAILED DESCRIPTION OF EMBODIMENTS

I. DEFINITIONS

[0026] Aspects disclosed herein generally relate to microwave heating of gangue produced by solvent-based methods for extracting bitumen from oil sands ores. Any term or expression not expressly defined herein shall have its commonly accepted definition understood by a person skilled in the art.

[0027] "Microwaves", as used herein, refers to electromagnetic radiation with frequencies in the range of 300 MHz to 300 GHz. In embodiments, microwaves have a frequency between 2 GHz to 4 GHz, more particularly a frequency of 915 MHz or 2.45 GHz, and even more particularly the frequency of 2.45 GHz. As known in the art, certain frequencies of microwaves (e.g., 915 MHz and 2.45 GHz) may be adopted for heating applications in North America to avoid interference with frequencies used for other purposes (e.g., communications, institutional, and military).

[0028] "Organic solvent", as used herein, refers to a non-aqueous fluid comprising molecules of a compound comprising carbon atoms covalently bonded to hydrogen atoms, and possibly atoms of other elements (e.g., oxygen), which fluid dissolves bitumen. A variety of organic solvents are known in the art. In embodiments, non-limiting examples of organic solvents include toluene, heptane, cyclohexane, methylcyclohexane, ethylbenzene, xylene, isoprene and limonene, or mixtures of one or more of the foregoing. In embodiments, organic solvents may be non-polar or polar. In embodiments, organic solvents may have normal boiling point temperatures that are less than the normal boiling point temperature of water. [0029] "Bitumen" is highly viscous crude oil which does not easily flow at room temperature. Bitumen extracted from oil sands, such as Alberta oil sands, typically has an API gravity of 8° to 14°. Bitumen may also be referred to as heavy oil or extra heavy oil, which typically has an API gravity of less than about 11°.

[0030] "Oil sands gangue", as used herein, refers to a mixture comprising water, solid mineral particles (e.g., sand and clay), bitumen, and an organic solvent that results from a solvent-based extraction process for extracting bitumen from oil sands ore, where the organic solvent in the mixture is residual from the solvent used in the solvent-based extraction process.

[0031] "Processor" refers to one or more electronic devices that is/are capable of reading and executing instructions stored on a memory to perform operations on data, which may be stored on a memory or provided in a data signal. The term "processor" includes a plurality of physically discrete, operatively connected devices despite use of the term in the singular. Nonlimiting examples of processors include devices referred to as microprocessors, microcontrollers, central processing units (CPU), and digital signal processors.

[0032] "Memory" refers to a non-transitory tangible computer-readable medium for storing information in a format readable by a processor, and/or instructions readable by a processor to implement an algorithm. The term "memory" includes a plurality of physically discrete, operatively connected devices despite use of the term in the singular. Non-limiting types of memory include solid-state, optical, and magnetic computer readable media. Memory may be non-volatile or volatile. Instructions stored by a memory may be based on a plurality of programming languages known in the art, with non-limiting examples including the C, C++, Python ™, MATLAB ™, and Java ™ programming languages.

II. EXAMPLE SYSTEMS

[0033] Fig. 1 A shows an example system (100a) for removing an organic solvent.

[0034] As shown, the system (100a) includes a container (16) for holding or supporting a mixture (14). Mixture (14) may comprise a mixture of an organic solvent, bitumen and mineral solids comprising sand and clay particles (e.g., gangue). In some examples, container (16) is a glass vial.

[0035] System (100a) also include a microwave source (10) for emitting microwaves at the mixture (14), contained within the container (16).

[0036] In at least one example, a gas source (22) is also provided. Gas source (22) may generate a flow of gas (e.g., nitrogen). The gas can be directed to flow past the mixture (14) in order to carry vaporized organic solvent away from the mixture (14), as explained in further detail below.

[0037] To that end, the system (100a) may additionally include an air-permeable support (18). Air-permeable support (18) supports the container (16) above the gas source (22), and allows gas to flow upwardly from the gas source (22) and around, and past the container (16). In this manner, the gas source (22) can be positioned below the container (16). A conduit (20) (e.g., a glass tube (20)) may also be located around the container (16), such that the flow of gas travels past the container (16), and is directed upwardly through the conduit (20).

[0038] In at least one example, one or more temperature sensors (12) are also included. The temperature sensors (12) can be positioned within, or proximal (e.g., surrounding) the mixture (14). As explained below, the temperature sensors (12) can monitor the temperature of the mixture (14) as microwaves are applied to the mixture (14). In some cases, the temperature sensors (12) generate corresponding temperature data, which may be received and logged onto a memory of a computer (not shown).

[0039] Fig. IB shows another example system (100b). System (100b) is generally analogous to the system (100a), but further includes a controller (50).

[0040] Controller (50) can be coupled (e.g., wired or wirelessly) to one or more of the microwave source (10), gas source (22) and temperature sensors (12). As explained below, controller (50) can automatically control all, or any part, of system (100b). For instance, controller (50) can transmit control data (or control instructions) to microwave source (10) and/or gas source (22), to control their operation. Controller (50) can also receive data from various system components, including receiving temperature data from the temperature sensors (12).

[0041] As shown in Fig. 12, controller (50) can generally include a processor (1202) coupled to one or more of a memory (1204), a communication interface (1206), an input interface (1208) and an input/output (I/O) interface (1210).

[0042] Communication interface (1206) can be any interface for communicating over a communication network, as known in the art. I/O interface (1210) can be used to couple to one or more system components (e.g., Figure IB).

[0043] Input interface (1208) is any interface for receiving inputs, e.g., from a user. This can include a keyboard and/or mouse, or a touchscreen interface (e.g., a capacitive touchscreen interface). In some cases, where the input interface (1208) is a touchscreen interface, the input interface can also be a display interface. While not shown, controller (50) can also include a separate display interface (e.g., LCD screen or the like).

[0044] Fig. 1C shows another example system (100c) for organic solvent extraction. In contrast to systems (100b) and (100c), system (100c) allows for continuous processing of oil sands gangue.

[0045] As shown, the system (100c) include a conveyance mechanism (102) (e.g., a conveyor belt). At one end of the conveyor (102), an input feeder (104) is positioned to deposit mixture (14) onto the conveyor (102). As the conveyor transports the mixture (14), the mixture (14) is subject to microwaves generated by microwave source (10). This, in turn, causes the organic solvent to vaporize into a head space.

[0046] The gas source (22) is positioned to generate a flow of gas (e.g., nitrogen). The gas is directed to carry the overhead vaporized organic solvent away from the mixture (14), and towards an organic solvent collector. In this example, the gas source (22) is positioned to direct gas flow in the same direction as the material (14) is conveyed. In other examples, the gas source (22) is positioned in any other suitable location, to generate gas flow in any other desired direction. For example, the gas flow can be directed in an opposite direction to the one in which the mixture (14) is conveyed, or it can also be positioned below the mixture (e.g., as shown in Figs. 1 A and IB).

[0047] As exemplified, a conduit (20) is provided to direct gas flow towards the collector. System (100c) can also include one or more temperature sensors (12).

[0048] Once the organic solvent is evaporated, the remaining residue in the gangue is conveyed to a downstream output (106).

[0049] While not shown, system (100c) can also include a controller (50) coupled to each of the system components, as shown in Fig. IB.

[0050] In some examples, a similar system configuration is used for batch processing of oil sand gangue. For example, batches of mixture (14) are conveyed on the conveyor (102) and exposed, one at a time, to the microwave source (10).

III. EXAMPLE METHODS

[0051] (i.) Example General Methods.

[0052] Fig. 11 A shows an example method (1100a) for removing an organic solvent from oil sands gangue comprising the organic solvent, bitumen and mineral solids comprising sand and clay particles.

[0053] In general, the method includes the following steps: (a) at act (1102a), if necessary, adding water to the gangue so that the mixture has a water content greater than 0 wt% by weight of the mineral solids. This step may be undertaken if it is initially determined that the mixture does not include a water content greater than 0 wt% by weight of the mineral solids; and (b) subsequently, at act (1106a), exposing the mixture with the water content to microwaves (e.g., using microwave source (10) (e.g., Figs. 1A and IB)) to heat the mixture and thereby vaporize at least a portion of the organic solvent from the mixture.

[0054] The method is not limited by the manner in which the mixture in produced. In some embodiments, the mixture is produced by a solvent-based extraction process for extracting bitumen from oil sands ore. In such embodiments, the mineral solids and the bitumen in the mixture are from the oil sands ore, and the organic solvent in the mixture is residual from the solvent-based process. In such embodiments, at least a portion of the water content may comprise connate water present in the oil sands ore.

[0055] The present invention may be used for mixtures having a variety of compositions. In embodiments, the bitumen content in the mixture is less than about 2 wt% by weight of the mineral solids. In embodiments, before step (b) of the method, the organic solvent content in the mixture may be less than or equal to about 12 wt% by weight of the mineral solid. In embodiments, before step (b) of the method, the water content in the mixture is at least about 3 %, 4%, 6%, 8%, 10% or 12% by weight of the mineral solids. In embodiments, before step (b) of the method, the water content in the mixture is less than or equal to about 12% by weight of the mineral solids.

[0056] The present invention may be used for mixtures having a variety of type(s) of organic solvent(s). In embodiments, the organic solvent may have a boiling point temperature less than the boiling point of water at a common pressure. In embodiments, the organic solvent may comprise a non-polar solvent, or a polar solvent. In embodiments, the organic solvent may comprise cyclohexane alone or in combination with other organic solvent(s). In other embodiments, the organic solvent may comprise other one or a combination of organic solvent(s) other than cyclohexane, such as described above. In some embodiments, where the mixture comprises, at least partially, polar organic solvents - it may not be necessary to undertake act (1102a), as microwave energy is able to heat and vaporize polar solvents, without the necessity for adding water content to the mixture. [0057] In some embodiments, the method (1100a) may further comprise, either before or after step (1102a), and before step (1106a) - the step (1104a) of allowing a portion of the organic solvent in the mixture to vaporize from a surface of the mixture exposed to air, without exposing the mixture to microwaves. This may reduce the amount of microwave energy that needs to be applied at step (1106a) to remove a desired amount of the organic solvent from the mixture.

[0058] In embodiments, the method (1100a) may further comprise, during and/or at least partially concurrently with step (1106a) - the step (1108a) of flowing a gas past the mixture to carry the vaporized organic solvent away from the mixture. For example, the gas may be generated by a gas source (22) (e.g., Figs. 1 A and IB). The vaporized organic solvent may be collected, condensed and used in a solvent-based process for extracting bitumen from an oil sands ore, thereby increasing the efficiency of the overall extraction process.

[0059] In at least one embodiment, during act (1106a), the method may further involve agitating the gangue, i.e., while the mixture is exposed to microwave energy. The agitation may allow re-distributing the heat within the mixture (14). In doing so, the heat is more evenly distributed within the mixture (14) which, in turn, facilitates more efficient vaporization of the organic solvent within the mixture (14), i.e., thereby expediting the vaporization process.

[0060] The agitation may be particularly useful, for example, where only a portion of the mixture (14) is receiving exposure to microwave energy, e.g., owing to the positioning of the microwave source (10) relative to the mixture (14). In these examples, the systems (100a) - (100c) may include an agitator (not shown).

[0061] In an example where method (1100a) is applied to a system for continuous processing (e.g., Fig. 1C) - there may be a system component, positioned before microwave source (10), which applies water at act (1102) to the mixture content. Further, the mixture (14) may be exposed to air, at act (1104a), also before it is subject to the microwave source (10). For example, this can occur while the mixture (14) is on the conveyor (102). With respect to act (1106a), the microwave energy and the gas flow may be applied constantly as the conveyor (102) is moving the mixture (14) (i.e., as shown in Fig. 1C). A similar method can also be applied, as well, for batch processing.

[0062] Fig. 1 IB shows an example method (1100b) for preforming act (1106a) of method (1100a), e.g., exposing microwaves to the mixture with water.

[0063] At (1102b), at least one output setting is determined for the emitted microwaves, which are being exposed to the mixture with water content. As explained below, the at least one outputting setting can be determined based on one or more output setting determining factors.

[0064] In at least one example, the determined output setting is in respect of an energy level - or a range of energy levels - for the emitted microwaves.

[0065] To that end, the person skilled in the art will be able to select (or determine) an appropriate amount of microwave energy to vaporize the organic solvent, having regard to one or more output setting determining factors, such as the mass, composition and temperature of the mixture, the desired time efficiency for the method, the desired removal rate of the organic solvent, and practical limits such as the power of the microwave source.

[0066] The output settings, determined at (1102b), can also involve determining a frequency - or a range of frequencies - for the emitted microwaves. For example, the microwaves can have a frequency in the range from about 2 GHz to about 4 GHz.

[0067] In some embodiments, the microwaves apply between about 6000 Joules to about 13000 Joules per gram of the gangue to the gangue, which is shown in the below examples to permit removal of cyclohexane as the organic solvent after exposing the mixture to microwaves for about 300 seconds.

[0068] In at least one embodiment, the output settings are configured into the microwave source (10) (Fig. 1A). For example, the microwave source (10) may have an input interface which allow a user to adjust the output settings of the emitted microwaves. The microwave source (10) is then able to emit microwaves with the desired output settings. [0069] At (1104b), the microwaves - at the determined output settings - are exposed to the mixture with water content.

[0070] At (1106b), in embodiments, the method may further comprise the steps of monitoring a temperature of the mixture during act (1106b) to detect a maximum temperature. For example, the temperature of the mixture can be monitored using one or more temperature sensors (12) (Fig. 1A).

[0071] At (1108b), it is accordingly determined if the mixture has reached the predetermined maximum temperature. If not, the method can return to (1106b), to continue monitoring the temperature. Otherwise, at (1110b) the temperature is then monitored (e.g., using temperature sensor (12)), to determine if the temperature then subsequently falls below the maximum pre-determined temperature. The decline from the maximum temperature may be indicative of the mixture losing its water content, which acts as the microwave susceptor, due to vaporization. Thus, vaporization of the water content can be avoided with a view to applying the method in an energy efficient manner.

[0072] At (1112b), it is determined if the temperature has fallen below the maximum temperature. If not, the method can return to monitoring at (1110b). Otherwise, at (1114b) the method involves ceasing exposure of the mixture to microwaves in response to the monitored temperature declining from the maximum temperature.

[0073] In some embodiments, the method (1100b) only involves preforming acts (1102b), (1104b) and (1114b). In other words, it may not be necessary to preform acts (1104b) - (1112b) in each case. In these examples, the mixture is exposed to the microwaves for a pre-determined period of time before the exposure is ceased, at (1114b).

[0074] In an example where method (1100a) is applied to a system for continuous processing (e.g., Fig. 1C), the system can be configured to ensure that any conveyed mixture (14) is exposed to microwave energy in accordance with acts (1106b) - (1112b), before it is conveyed away from the microwave source (10). This may involve stopping movement of the conveyor (102) until act (1112b) is satisfied. Otherwise, it may involve configuring the conveyor speed to allow act (1112b) to be satisfied, before the mixture (14) is transferred to the output (106).

[0075] (ii. ) Example Method for Cyclical Recovery and Re-use of Organic Solvent.

[0076] Fig. 11C shows an example method (1100c) for cyclical recovery and re-use of organic solvent.

[0077] As shown, the method involves the production of gangue (1102c) during bitumen (1104c) extraction. The gangue (1102c) include a mixture of bitumen (1104c), organic solvent (1106c) among other elements. The gangue (1102c) is then exposed to microwaves (1108c) (e.g., in accordance with the methods in Figs. 11 A and 1 IB), which results in gangue without solvent (1114c).

[0078] The vaporized organic solvent (1110c) - resulting from microwave exposure - is then condensed, back into liquid form, via any suitable condensation process (1112c). The liquid organic solvent (1106c) is then re-used during a new bitumen extraction process.

[0079] (Hi.) Example Automated or Semi-Automated Methods.

[0080] In some examples, all - or any portion - of methods (1100a) and (1100b) (Figs. 11 A and 1 IB) are automated or semi-automated.

[0081] Fig. IB exemplifies a system (100b) for removing organic solvent from a mixture, which additionally includes the controller (50), which can be used to automate the methods described herein. In this example, controller (50) can automatically control operation of one or both of the microwave source (10) and gas source (22).

[0082] For example, the method (1100a) (Fig. 11 A), can further involve - at act (1106a) - controller (50) operating (e.g., activating) the microwave source (10) to expose microwaves to the mixture with water content. Further, act (1108a) can involve the controller (50) operating (e.g., activating) the gas source (22) to generate gas that flows past the mixture. Controller (50) can also operate the microwave source (10) and gas source (22) such that acts (1106a) and (1108a) are performed concurrently, or partially concurrently.

[0083] Similarly, controller (50) can automatically preform all, or any portion, of method (1100b) (Fig. 1 IB). For example, at act (1102b), the controller (50) can receive the at least one output setting (e.g., via a user input interface), and at act (1104b), can further automatically control the microwave source (10) to emit microwaves at the determined output settings.

[0084] In other examples, at (1102b), the controller (50) can also simply receive the one or more output setting determining factors (e.g., mass, composition and temperature of the mixture, etc.). In these cases, controller (50) may, itself, automatically determine the corresponding output settings.

[0085] In some embodiments, controller (50) can also automatically preform acts (1106b) - (1112b). For instance, controller (50) may also be coupled to the one or more temperature sensors (12) (Fig. IB). Accordingly, controller (50) can receive and monitor temperature data from the temperature sensors (50) at acts (1106b) and (1110b). Based on the monitored temperature data, the controller (50) can make the determinations at acts (1108b) and (1112b).

[0086] At (1114b), the controller (50) may also automatically operate the microwave source (10) to cease emitting microwaves (e.g., de-activate the microwave source (10). While not shown, controller (50) can also concurrently operate (e.g., de-activate) the gas source (22) to cease generating gas.

[0087] For continuous (or batch) processing (Fig. 1C), controller (50) may also control the conveyor (102) speed, as well as activating or de-activing the conveyor (50).

IV. EXAMPLE IMPLEMENTATION OF THE SYSTEMS AND METHODS

[0088] The following are non-limiting illustrative examples of implementations of the methods and systems of the present invention, and methodologies used to demonstrate the efficacy thereof. [0089] While the examples are performed using laboratory equipment, it will be appreciated that the underlying principles of the invention may be adapted for use in industrial applications to process large volumes of oil sands gangue produced by a solvent-based bitumen extraction process.

[0090] (i.) Example preparation of reconstituted oil sands gangue samples.

[0091] Since the residual bitumen and cyclohexane contents of a gangue obtained from the solvent extraction of an oil sands ore may vary significantly, it is difficult to have a control on the composition of the extraction gangue. Thus, reconstituted gangue samples were prepared with controlled compositions based on the protocol described in Reference no. 9 (Panda et al.) for the purpose of demonstrating the efficacy of the method of the present invention.

[0092] A rich oil sands ore sample provided by Syncrude Canada Ltd. was used. The ore sample was extracted using cyclohexane (purity 99.0%, certified ACS grade; Fischer Scientific, United States) in a Dean-Stark extraction apparatus (see Reference no. 10: Khalkhali et al.) The solvent was condensed in the trap and allowed to overflow back over the sample placed in a thimble, to dissolve and to extract the bitumen. The extraction was stopped when the solvent dripping out of the thimble was visually clear.

[0093] The thimble containing the extracted ore was dried to obtain mineral solids. The amount of collected water could be read from the calibrated trap, and bitumen content could be determined by either mass balance (initial weight of the ore as well as weight of the extracted mineral solids and water are known) or removal of solvent from the solution obtained from the extraction. The mixture of fine solids (including clay particles) and coarse solids (including sand particles) obtained by drying the collected solids in the thimble is referred to herein as "Soxhlet solids" (SS). For all the reconstituted samples in this example, the fraction of solids particles larger than 500 pm were separated from the rest of the Soxhlet solids to facilitate mixing and distribution of bitumen on solids surfaces.

[0094] After the extraction, the solvent-wetted solids were allowed to dry, first at ambient pressure and room temperature for 1 hour, then in a vacuum oven working at 80 °C and 30 mbar for 12 hours. As described before, only trace amounts of fine solids (1.5 wt% of total fines) were transferred into the extracted bitumen/cyclohexane solution. Thus, the measured fines content in the extracted Soxhlet solids was assumed to be the same as the original fines content in the ore. The extracted thimble was weighed after the discharge of Soxhlet solids to measure the weight of fine solids trapped in the pores of the thimble. The discharged dry Soxhlet solids were dry-sieved using a 45 pm aperture to isolate fine solids. The fine particle content of the ore sample was calculated using the weight of fine solids separated by drysieving and that trapped in the pores of the extraction thimble. The average fine particle content of the solids used in this example was 6.8 ± 0.9 wt%.

[0095] Reconstituted gangue samples were prepared by the same approach described in Reference no. 9 (Panda et al.). In general, a controlled amount of water (e.g., 4 to 12 wt% by weight of the dry Soxhlet solids) was added to the dry Soxhlet solids, mixed with a rotary mixer, and allowed to age. Subsequently, a controlled amount of cyclohexane (e.g., 12 wt% by weight of the dry Soxhlet solids) was added to the wet Soxhlet solids, and mixed with a rotary mixer to produce the reconstituted gangue samples. The reconstituted gangue samples were kept in the freezer at -13 °C. The sealed samples were let to thaw for 5-10 minutes before packing for either air drying or microwave heating, as discussed below.

[0096] (ii. ) Example air drying setup.

[0097] For each comparative air-drying run, 25.2 ± 0.2 g of a reconstituted gangue sample was packed into a Pyrex CLS316060 ™ glass Petri dish (60 mm OD, 50 mm ID, 15 mm height) to a bed height of 1 cm. The weight and the bed height were fixed to maintain a constant bulk density of 1.28 ± 0.01 g/cm ³ for all samples. The time spent on packing before starting the drying experiment was less than 60 seconds for all samples. Once packed, samples were put on a balance in the fume hood and allowed to dry at room temperature and ambient pressure. The balance was connected to a computer, which logged the measured weight every 20 seconds. [0098] (Hi.) Example experimentation microwave heating system set-up.

[0099] Fig. 1 A depicts an example schematic of the microwave heating system used in this example experimental setup.

[00100] The system included a laboratory microwave source (10) (model MH2.0W-S ™, National Electronics, a division of Richardson Electronics, Ltd.; LaFox, IL, USA), 2 kW switch-mode power supply (model SM745G.1 ™, Alter Corp.), an isolator (National Electronics), a three-stub tuner (National Electronics), a single mode waveguide applicator, and a sliding short (not shown in Fig. 1 A).

[00101] Before each experiment, the tuner and the sliding short were used to adjust the microwave impedance and maximize the energy transfer to the sample. Applied microwave power was monitored using a dual channel microwave power meter (model E4419B ™, Agilent Technologies, Inc., Santa Clara, CA, USA) and two power sensors (8481 A ™, Agilent Technologies, Inc.; Santa Clara, CA, USA) connected to a dual directional coupler with 60 db nominal attenuation (Mega Industries; Gorham, ME, USA).

[00102] To avoid interference with the applied microwave, a temperature sensor (e.g., fiber optic thermocouple) (12), with a signal conditioner (Reflex ™ signal conditioner, Neoptix Inc.; Quebec City, QC, Canada) was used to measure the sample temperature during microwave heating.

[00103] A Lab VIEW ™ program (National Instruments) connected to a data acquisition system (computer processor) was used to record microwave applied power and sample temperature during the microwave heating, to a memory (i.e., a non-transitory computer- readable medium).

[00104] Microwave regeneration times (4.2 - 8.8 min) and microwave powers (105 - 215 W) were varied, but the most common conditions were 5 min and 180 W. The microwave regeneration time is the time at which a solid material (e.g., gangue, adsorbent, etc.) loses all the organic solvent molecules. In other words, microwave regeneration time is the time needed to irradiate the gangue with microwaves in order to purify it from cyclohexane.

[00105] For a reconstituted gangue sample of about 5 g in mass (as described below), and a microwave exposure time of 300 seconds, these microwave power parameters equate to a minimum and maximum microwave energy of about 6.3 kJ / g and 12.9 kJ/g, respectively, calculated as follows.

Minimum microwave energy requirement per gram of gangue:

105 VF x 300 s

Maximum microwave energy requirement per gram of gangue:

215 VF x 300 s

5 g x 1000

[00106] The temperatures of the samples were recorded every second.

[00107] For each microwave heating experiment, 5.07 ± 1.05 g of reconstituted gangue (14) was packed into a container in the form of a glass vial (16) with a height of 4 cm, and an outer diameter of 1.9 cm (DWK Life Sciences; Milville, NJ, USA). Sample height in the vial was kept at 1.5 cm to ensure consistent microwave heating among different runs.

[00108] A gas source (22) was used to emit a one (1) standard litre per minute (SLPM) stream of ultrapure nitrogen (99%) flowing upwardly through an air-permeable support (18) to sweep the evaporated water/cyclohexane from the glass vial (16) and upwardly through a conduit in the form of a glass tube (20).

[00109] The system may be adapted with additional equipment (e.g., collection vessels, coolers, conduits and so forth) to collect and condense the vaporized water/cyclohexane from the conduit, so that the cyclohexane in liquid form may be re-used in a solvent-based process to extract additional bitumen from additional oil sands ore. [00110] (iv.) Example residual solvent determination.

[00111] To determine the amount of residual solvent in the gangue samples before, during and after microwave heating, toluene was used to extract the cyclohexane from each sample. Then, a gas chromatograph (GC) equipped with a flame-ionization detector (FID) was used to analyze the amount of dissolved cyclohexane in toluene. To do so, the gangue samples were subjected to a three-step solvent extraction by toluene. The three-step extraction process was conducted on three sub-samples (n = 3) of each reconstituted gangue sample to extract all cyclohexane in the gangue during the microwave heating process.

[00112] In general, in each extraction step, a mass of Ti of toluene was added to a vial containing the gangue sample (see Fig. 2A). The mixture was shaken for 15 minutes, and left for 24 hours (see Fig. 2B). A mass, Mi, of the supernatant in the i ^th extraction was collected and injected into the GC column (see Fig. 2C). An average cyclohexane content of CHt (based on 3 samples) was obtained for each supernatant and later used to calculate the residual cyclohexane in the sample.

[00113] The GC analysis was carried out in a Varian 430 ™ GC with an FID detector and 30 m, 0.53 mm ID, and 0.5 pm capillary column (Stabilwax-DA ™). The injector temperature, split ratio, the constant flow of the carrier gas at 250 °C were 5, and 10 mL/min, respectively. The temperature was set initially at 45 °C and was increased with no hold to 120 °C at 45 °C/min and held at 120 °C for 1 min. The total runtime was 285 seconds. The calibration curve was obtained by injecting triplicates of standard solutions of 0.1, 1, and 10 wt% of cyclohexane in toluene.

[00114] To elaborate, for the first extraction, a mass T of about 10 g of Toluene was added to a mass, MRG, of reconstituted gangue sample, previously frozen in -13 °C. The mixture was sealed and shaken manually for 15 minutes, before being left for 24 hours at room temperature. A mass, of about 5g of the supernatant in the mixture was siphoned out and later used for GC analysis. The resulting cyclohexane content in the 1 ^st supernatant, obtained from GC, is represented by CH\. Therefore, the mass of cyclohexane extracted in the first step (mi) can be written as follows:

[00115] Note that here the masses of bitumen and fine solids that are transferred in addition to cyclohexane to toluene bulk phase are neglected and thus, in equation (Al), CH. is considered to be equal to m./(mi+ Ti).

[00116] For the second extraction, T2 g of toluene was added to the sample plus the remaining toluene phase from the first extraction. The mixture was treated the same as the first extraction. M g of the supernatant was siphoned out and used for GC analysis. The resulting cyclohexane content in the second supernatant, obtained from GC, is represented by CHi as follows: where m'i and mi are the masses of the remaining cyclohexane which was extracted in the first step and the mass of newly extracted cyclohexane after adding Ti g of toluene. Using equations (A2) and (A3), m2 can be determined as follows:

[00117] For the third and final extraction step, Ti g of toluene was added to the mixture and the same protocol for the first and second extractions was followed. Here, Mi g of the supernatant was siphoned and injected to the GC column. The obtained cyclohexane content (CH.) was used to calculate the mass of cyclohexane extracted in the third extraction, as follows: m2 = CH 2 (T ! + T ₂ + m. + m ₂ - M. - M ₂ (A6)

[00118] Equations (A1)-(A7) can be presented in one equation for the i ^th extraction, where any parameter with a zero index is equal to zero, as follows:

T _Q , M _Q , m ₀ , CH _o = O for m< is ignored if there is no cyclohexane peak detected in GC analysis (i.e., if CHt = 0). In such cases and m is considered to be zero. Finally, the residual cyclohexane content is determined for each sample as follows:

[00119] (v.) Example methodology to determine effect of microwave heating on sample temperature.

[00120] To determine the effect of microwaves on heating of the reconstituted gangue sample and its constituent components, microwave heating was carried out on reconstituted gangue (RG) samples, samples containing only Soxhlet solids (SS), samples containing Soxhlet solids plus bitumen (DSBS), and samples of pure cyclohexane liquid, as summarized in Table 1 of Fig. 3.

[00121] In this example, the contents of different components in the samples are calculated as parts of component/100 parts of Soxhlet solids by mass, rather than the total mass of the samples. In other words, the weight percentages of bitumen, water and cyclohexane are calculated based upon 100% SS. Nonetheless, the contents of these components are expressed as "wt%" herein and in Table 1. For example, in Table 1 of Fig. 3, a constituted gangue sample RG 2 having 100 g of Soxhlet solids would contain 1.15 g of bitumen, 12 g of water, and 12 g of cyclohexane.

[00122] Figs. 4 and 5 show the temperature profile during microwave heating of the samples depicted in Table 1, over a time period 0 to 5000 seconds (Fig. 4), and the initial time period of 0 to 800 second (Fig. 5). The small temperature changes (< 25 °C) observed for pure Soxhlet solids (SS), Soxhlet solids with bitumen (DSBS), and pure liquid cyclohexane, respectively, demonstrate that Soxhlet solids, bitumen, and cyclohexane weakly absorb microwaves. As shown in Fig. 4, the final temperatures of samples RG1 and RG2 at time around 5,000 seconds are higher than those of the other samples. This is likely due to the present of a small amount of residual water that still stays in the gangue.

[00123] As shown in Fig. 5, however, when water is present in the samples, the temperature increase was noticeable and took place rapidly, essentially in the first four hundred seconds for both RG 1 and RG 2. Only one plateau (100 °C) is observed for sample RG 1 while two plateaus (68 °C and 100 °C) are observed for sample RG 2. The plateaus signify the vaporization of water and cyclohexane, respectively.

[00124] As mentioned earlier, the normal boiling points of cyclohexane and water are 81 °C and 100 °C, respectively. Clearly, cyclohexane starts to vaporize at a temperature below its normal boiling point, but this is not the case for water. This is attributed to the fact that the two liquids are immiscible, such that cyclohexane's boiling point is depressed as a result of increasing activity. Therefore, the immiscibility effect did not occur to water as most of the cyclohexane has vaporized by the time water started to vaporize.

[00125] Another noteworthy point is that the heating mechanisms for cyclohexane and water are different. In the case of water, it is the direct interaction between the electric field of the microwave and the dipole of the water molecules that leads to the heating. However, heating of cyclohexane is through the energy transfer due to the molecular collisions between the two unlike molecules. Without restriction to a theory, the water acts as a heating agent and microwave susceptor. Microwaves generate heat inside polar material (i.e., water) whereas non-polar material (e.g., cyclohexane) and nonconductive material (e.g., clay particles) poorly absorb microwaves and are not heated (see References no. 11 : Falciglia et al.; and no. 12: Jones et al.). The process benefits from the microwave absorption ability of water. Microwaves mainly heat the water present in the sample resulting in lower power consumption than would be required of conventional heating to heat the entire sample.

[00126] The heating curves of both sample RG 1 and sample RG 2 reach a maximum temperature of 120 °C before the temperature starts to decrease. The temperature of the samples decreased after the peak time, suggesting that the sample was losing its water content (heating agent) due to vaporization. In other words, one can essentially stop the microwave heating upon reaching the maximum temperature at around 400 seconds, which is a relatively short period of time. This maximum temperature (120 °C) may be attributed to the further heating of the water vapor in the gangue prior to its departure of the gangue.

[00127] (vi.) Effect of water content on cyclohexane removal efficacy and rate.

[00128] The results reported in Figs. 4 and 5 clearly show that water helps to remove cyclohexane even though cyclohexane is transparent to microwaves. Therefore, microwave heating was performed on gangue samples with different water contents (4, 6, and 12 wt%) to check if there exists an optimum water content to remove cyclohexane at a given content (12 wt%) over a period of 780 seconds, which is a time that the sample temperature would start to decrease. These samples are referred to herein as RG780-W4, RG780-W6, RG780-W12, respectively.

[00129] In addition, to study the rate of cyclohexane removal, the residual cyclohexane contents of a reconstituted gangue sample that contained 6 wt% water and 12 wt% cyclohexane were measured at different times (90, 140, and 300 seconds) during the microwave heating. These samples are herein labeled RG90-W6, RG140-W6, RG300-W6, respectively. Again, it will be noted that "wt%" of water and cyclohexane described herein for these samples are determined relative to the mass of dry solids in the sample, rather than relative to the total mass of the sample.

[00130] Fig. 6 shows the temperature evolutions of the reconstituted gangue samples, RG780-W4, RG780-W6, RG780-W12, with different water contents versus microwave heating time. All three curves resemble each other with two plateaus (one at 68 °C while the other at 100 °C) and the temperature starts to decrease at around 400 seconds. However, in the case of 4 wt% water, the peak temperature is only slightly higher than 100 °C rather than at around 120 °C. This is likely due to only a small amount of water being superheated in the gangue. However, as shown in Table 3 of Fig. 9, the 4 wt% water sample contains about 350 ppm residual cyclohexane while cyclohexane was not detected in the 6 and 12 wt% samples after the microwave heating.

[00131] To determine the cyclohexane contents in various RG samples, upon completion of the microwave heating, they were immediately capped, sealed with Parafilm ™, and stored at -14 °C for subsequent gas chromatographic analysis. The weights of each sample were recorded, to an accuracy of 0.1 mg, before and after the microwave heating.

[00132] Given that water and cyclohexane are the only two volatile components in the RG samples, volatile mass loss is calculated using Eq. (1). where Mi and Mf are the initial (before microwave heating) and final mass (after microwave heating) of the RG samples. The volatile mass fraction based on the entire RG sample (XVOIRG) is calculated as follows: xw + ^X CH Eq. (2)

^X VOIRG 11 + Xb _it + x v _w j +- X v _C H

Here, Xbu, x _w , andxc/r are bitumen, water, and cyclohexane weight fractions based on the mass of dry Soxhlet solids. [00133] The mean and standard deviation (n = 3) values for the volatile mass loss results are shown in Table 2 of Fig. 7. These results show that after 780 seconds of microwave heating, when the temperature starts to decrease, more than 90% of volatiles were vaporized. In fact, volatile mass loss increases with increasing water content, and it reaches near 100% for sample RG780-W12. The water content dependence of volatile mass loss may be due to the increasing amount of water loss.

[00134] Fig. 8 shows the volatile mass loss for the RG sample with 6 wt% water (solid line in Fig. 8) increases with increasing microwave heating time. The volatile mass loss curve is constructed based on 4 data points of the sample subjected to microwave heating for 90, 140, 300, and 780 seconds. These times (except 780 seconds) were chosen based on the end points of the plateaus indicated in the representative temperature profile (dashed line in Fig. 8) for samples with 6 wt% water.

[00135] It is noteworthy that the volatile mass loss plot constructed based on the data points from the microwave heating resembles the volatile mass loss plots of the air-drying of RG samples under ambient conditions presented in Reference no. 6: Nikakhtari et al. However, there are two major differences between the selective microwave heating and air-drying at ambient conditions. One is that the microwave heating process occurs in minutes while air drying occurs in hours. The other is the mechanism by which cyclohexane leaves the gangue. In the air drying, cyclohexane flows as a liquid to the gangue surface and vaporizes. While in microwave heating, cyclohexane vaporizes in the gangue and flows as a vapor to the gangue surface. In fact, the gas phase diffusion rate of cyclohexane is considerably higher than its liquid phase diffusion rate, which results in a shorter heating time with microwave heating compared to air drying technique. Nevertheless, in both modes of drying, cyclohexane leaves the gangue first followed by the water.

[00136] To determine the effect of water content on the amount of cyclohexane being removed, the residual cyclohexane content in the gangue after microwave heating needs to be measured. Table 3 of Fig. 9 summarizes the residual cyclohexane content in the gangue after microwave heating for the samples, using the gas chromatograph (GC) analysis described above, under the heading "Residual solvent determination", using the values summarized in Table 4 in Fig. 10. The results reported are the average values along with the standard deviations (n = 3). To verify the accuracy of the GC method, the initial cyclohexane content of RG780-W4, which was known to be 12 wt%, was also tested and this sample is referred to as RG-Ref in Tables 3 and 4.

[00137] In addition, GC tests were carried out to determine the residual cyclohexane contents of one additional RG sample containing 4 wt% water and 12 wt% cyclohexane initially but air dried under ambient conditions for 30 (1,800) and 120 (7,200) minutes (seconds) following the procedure described in Reference no. 7: Tan et al.; these samples are labeled as RGAD1800-W4 and RGAD7200-W4 in Tables 3 and 4.

[00138] The cyclohexane content of RG-Ref as determined by the GC method using the total weight of the gangue (i.e., 9.4 ± 0.7 wt%) was within the experimental uncertainties of the expected cyclohexane content (i.e., 10.3 wt% based on the total weight of the gangue or 12 wt% based on the dry Soxhlet solids), thus verifying that the accuracy of the proposed method for determining residual cyclohexane in the gangue is reasonable.

[00139] The results in Table 3 show that microwave heating is very effective in solvent removal from porous media such as the gangue used in this work, as cyclohexane content has dropped from 103,000 ppm (10.3 wt%) to undetectable level in only 780 seconds in the samples containing 6 and 12 wt% water, initially. Even in the case of RG780-W4, there was only 350 ± 70 ppm cyclohexane in the sample containing 4 wt% water. Comparing the microwave heating results to those of air-drying, microwave heating is a much rapid method for cyclohexane removal. In the case of RG300-W6, the cyclohexane content dropped to an undetectable level after only 300 seconds of microwave heating.

[00140] It was previously demonstrated that high water contents are detrimental for effective cyclohexane removal in the air-drying under ambient conditions as water interferes with the cyclohexane liquid flow to the gangue surface (see Reference no. 7: Tan et al.). The results here indicate that having some water or higher water contents help cyclohexane removal as water, an effective microwave susceptor, is needed or at least beneficial in the process.

[00141] Finally, the results of air-dried samples verified the finding in Reference no. 7 (Tan et al.) that the initial stage of air-drying is cyclohexane-dominated vaporization at the gangue surface, where almost 85% of the cyclohexane vaporizes in the first 30 minutes of drying under ambient conditions. In light of the above results, to further reduce the microwave energy used for removing cyclohexane from the gangue, one can carry out the air-drying for about 30 minutes before the gangue sample is exposed to microwave heating. Water can be added at the outset or after the air-drying step. However, to speed up the cyclohexane removal process, one can skip the air-drying step, but more microwave energy would need to be consumed.

[00142] To summarize, the results discussed herein demonstrate the feasibility of using microwave heating to remove liquid cyclohexane present in gangue, a porous medium, rapidly when water is used as a heating agent. The amount of liquid cyclohexane removed increases with increasing amount of water present and that the presence of 6 wt% water in the gangue suffices to completely remove 12 wt% of liquid cyclohexane initially present in the gangue, in only about 300 seconds. The microwave heating process compares favorably in terms of the rate and amount of cyclohexane removed with a similar air-drying process under ambient conditions previously reported by the inventors.

[00143] It is notable that in the ambient air-drying, water is detrimental to the drying process while water facilitates cyclohexane removal in the microwave heating process. This is because microwave heating is selective and energy is directly absorbed by the water molecules, not by the other gangue components, and is later transferred to nearby cyclohexane molecules to vaporize them. Since oil sands ores normally contain about 3-4 wt% of connate water, it means that addition of a small amount of water to the gangue would suffice to remove the residual cyclohexane present in a gangue sample rapidly. Since the microwave heating process is selective, the energy input is minimal compared to the direct heating of the entire gangue sample. The removal process relies on the fact that cyclohexane has a normal boiling point lower than that of water and that cyclohexane is vaporized prior to the vaporization of water. V. OTHER EXAMPLE APPLICATIONS

[00144] The foregoing working examples demonstrate the effectiveness of the present invention to remove cyclohexane from mixtures comprising cyclohexane, bitumen and mineral solids comprising sand and clay particles. Embodiments described herein are also effective in removing other types of organic solvents from such mixtures, when applied to such mixtures, provided the solvent may be vaporized by heating the mixtures by microwave energy.

[00145] As explained above, without restriction to a theory, it is believed that the principle of the present invention is the direct interaction between the electric field of the microwaves and the dipole of the water molecules in the mixture leads to the heating of the water. The water acts as a heating agent and microwave susceptor, and molecular collisions between the water and cyclohexane molecules transfers energy to the latter, thereby increasing the temperature of cyclohexane sufficiently to vaporize the cyclohexane.

[00146] It is believed that this mechanism would apply to other types of organic solvents, whether they comprise components that are polar or non-polar (like cyclohexane), or components that have normal boiling points above the normal boiling point of water or below the boiling point of water (like cyclohexane). If the organic solvent includes polar components, then such components may themselves interact with the microwaves and act as microwave susceptors. If the organic solvent includes components with normal boiling points above the normal boiling point of water, then the present invention may still be effective if microwave heating is sufficient to heat the mixture to a temperature above the boiling point of the organic solvent, to cause its vaporization. This may be possible if, for example, the normal boiling point of the organic solvent in the mixture may be depressed, as was observed in the case of mixtures containing cyclohexane.

[00147] It may also be possible if, for example, the microwave heating heats the temperature of the mixture to temperatures greater than the boiling point of water, as was observed in the case of mixtures containing cyclohexane. As still another example, the energy input of microwave heating may be supplemented by other energy sources. With the benefit of the disclosure herein, the person of ordinary skill in the art will be able to determine suitable parameters (e.g., microwave power, duration of exposure of microwaves) to effect vaporization of a particular organic solvent, without the need for undue experimentation.

VI. EXEMPLARY ASPECTS

[00148] In view of the described apparatuses, and methods and variations thereof, certain more particularly described aspects of the invention are presented below. These particularly recited aspects should not however be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein, or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language literally used therein.

[00149] Aspect 1A: A method for removing an organic solvent from oil sands gangue comprising the steps of: if necessary, adding water to the gangue so that the gangue has a water content greater than 0 wt% by weight of mineral solids in the gangue; and exposing the gangue to microwaves to heat the gangue and thereby vaporize at least a portion of the organic solvent from the gangue.

[00150] Aspect IB : A system for treating oil sands gangue resulting from an oil sands solvent extraction method, the system comprising: a container or conveyor for holding or supporting the gangue; a microwave source for emitting microwaves at the gangue in the container or conveyor; and a gas source for creating a flow of gas past the gangue to carry vaporized organic solvent away from the gangue.

[00151] Aspect 2: The method of Aspect 1A, wherein the gangue comprises a mixture produced by a solvent-based process using the organic solvent for extracting bitumen from an oil sands ore, wherein the mineral solids in the gangue are from the oil sands ore, and wherein the organic solvent in the mixture is residual from the solvent-based process.

[00152] Aspect 3: The method of any one of Aspect 1A and 2, wherein at least a portion of the water content comprises connate water present in the oil sands ore. [00153] Aspect 4: The method of any one of Aspect 1 A and Aspects 2 to 3, wherein, before step (b), the organic solvent content in the gangue is less than or equal to about 12 wt% of the mineral solids.

[00154] Aspect 5: The method of any one of Aspect 1A and Aspects 2 to 4, wherein the bitumen content in the gangue is less than about 2 wt% of the mineral solids.

[00155] Aspect 6: The method of any one of Aspect 1 A and Aspects 2 to 5, wherein, before step (b), the water content in the gangue is at least about 3 wt% of the mineral solids.

[00156] Aspect 7: The method of any one of Aspect 1A and Aspects 2 to 6, wherein, before step (b), the water content is at least about 4 wt% of the mineral solids.

[00157] Aspect 8: The method of any one of Aspect 1A and Aspects 2 to 7, wherein, before step (b), the water content is at least about 6 wt% of the mineral solids.

[00158] Aspect 9: The method of any one of Aspect 1 A and Aspects 2 to 8, wherein, before step (b), the water content is less than or equal to about 12 wt% of the mineral solids.

[00159] Aspect 10: The method of any one of Aspect 1A and Aspects 2 to 9, wherein the organic solvent has a boiling point less than the boiling point of water at a common pressure.

[00160] Aspect 11 : The method of any one of Aspect 1A and Aspects 2 to 10, wherein the organic solvent comprises a non-polar solvent, such as cyclohexane.

[00161] Aspect 12: The method of any one of Aspect 1 A and Aspects 2 to 11, wherein the organic solvent comprises cyclohexane.

[00162] Aspect 13: The method of any one of Aspect 1A and Aspects 2 to 12, wherein in step (b), the microwaves have a frequency in the range from about 2 GHz to about 4 GHz.

[00163] Aspect 14: The method of any one of Aspect 1A and Aspects 2 to 13, wherein in step (b), the microwaves apply between about 6000 Joules to about 13000 Joules per gram of the gangue to the gangue. [00164] Aspect 15: The method of any one of Aspect 1A and Aspects 2 to 14, further comprising the steps of: monitoring a temperature of the gangue during step (b) to detect a maximum temperature; and ceasing exposure of the gangue to microwaves or decreasing the energy of the microwavves in response to the monitored temperature declining from the maximum temperature.

[00165] Aspect 16: The method of any one of Aspect 1A and Aspects 2 to 15, further comprising, either before or after step (a) and before step (b), the step of allowing a portion of the organic solvent in the gangue to vaporize from a surface of the gangue exposed to air, without exposing the gangue to microwaves.

[00166] Aspect 17: The method of any one of Aspect 1A and Aspects 2 to 16, further comprising, during step (b), the step of flowing a gas past the gangue to carry the vaporized organic solvent away from the gangue.

[00167] Aspect 18: The method of any one of Aspect 1A and Aspects 2 to 17, wherein the system further comprises a conduit containing the container, wherein the gas source is adapted to create the flow of gas in the conduit.

[00168] Aspect 19: The method of any one of Aspect 1A and Aspects 2 to 18, wherein the microwave is generated at at least one output setting, the at least one output setting being determined based on one or more output setting determining factors.

[00169] Aspect 20: The method of any one of Aspect 1A and Aspects 2 to 19, wherein the output setting determining factors include one or more of the mass, composition and temperature of the gangue, the desired time efficiency for removing the organic solvent, the desired removal rate of the organic solvent, and practical limits of the microwave source.

[00170] Aspect 21 : The method of any one of Aspect 1A and Aspects to 2 to 20, further comprising condensing the vaporized organic solvent into a liquid organic solvent, and using the liquid organic solvent for bitumen extraction.

[00171] Aspect 22: The system of Aspect IB, further comprising a temperature sensor for generating temperature data of the gangue over time, and a computer operatively connected to the temperature sensor for acquiring the temperature data and recording the temperature data to a memory.

[00172] Aspect 23: The system of any one of Aspect IB and Aspect 22, wherein the microwave source is operated to generate microwaves at at least one output setting, the at least one output setting being determined based on one or more output setting determining factors.

[00173] Aspect 24: The system of any one of Aspect IB and Aspects 22 to 23, wherein the output setting determining factors include one or more of the mass, composition and temperature of the gangue, the desired time efficiency for removing the organic solvent, the desired removal rate of the organic solvent, and practical limits of the microwave source.

[00174] Aspect 25: The system of any one of Aspect IB and Aspects 22 to 24, further comprising a controller coupled to one or more of the microwave source, the gas source, and the temperature sensor.

[00175] Aspect 26: The system of any one of Aspect IB and Aspects 22 to 25, wherein the controller is configured for: operating the microwave source and gas source; receiving temperature data from the temperature sensor; based on the temperature data, monitoring a temperature of the gangue to detect that the temperature has reached a maximum temperature; further monitoring the gangue to determine that the temperature has fallen below the maximum temperature; and in response to detecting the temperature has fallen below the maximum temperature, de-activating the microwave source to ceasing exposure of the gangue to microwaves.

[00176] Aspect 27: The system of any one of Aspect IB and Aspects 22 to 26, wherein the controller is further configured for: initially, determining the at least one output setting for the microwaves based on the one or more output-setting determining factors; and operating the microwave source to emit microwaves at the determined at least one output setting.

[00177] Aspects 28: The system of any one of Aspect IB and Aspects 22 to 27, wherein the system further comprises a conduit containing the container or conveyor, wherein the gas source is adapted to create the flow of gas in the conduit.

[00178] Aspect 29: A method for removing an organic solvent from a gangue comprising the organic solvent, bitumen and mineral solids comprising sand and clay particles, comprising or consisting essentially of any combination of steps, elements or features disclosed herein.

[00179] Aspect 30: A system for removing an organic solvent from a gangue comprising the organic solvent, bitumen and mineral solids comprising sand and clay particles, comprising any combination of steps, elements or features disclosed herein.

VII. INTERPRETATION

[00180] The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims appended to this specification are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed.

[00181] References in the specification to "one embodiment", "an embodiment", etc., indicate that the embodiment described may include a particular aspect, feature, structure, or characteristic, but not every embodiment necessarily includes that aspect, feature, structure, or characteristic. Moreover, such phrases may, but do not necessarily, refer to the same embodiment referred to in other portions of the specification. Further, when a particular aspect, feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of one skilled in the art to affect or connect such module, aspect, feature, structure, or characteristic with other embodiments, whether or not explicitly described. In other words, any module, element or feature may be combined with any other element or feature in different embodiments, unless there is an obvious or inherent incompatibility, or it is specifically excluded.

[00182] It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for the use of exclusive terminology, such as "solely," "only," and the like, in connection with the recitation of claim elements or use of a "negative" limitation. The terms "preferably," "preferred," "prefer," "optionally," "may," and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.

[00183] The singular forms "a," "an," and "the" include the plural reference unless the context clearly dictates otherwise. The term "and/or" means any one of the items, any combination of the items, or all of the items with which this term is associated. The phrase "one or more" is readily understood by one of skill in the art, particularly when read in context of its usage.

[00184] The term "about" can refer to a variation of ± 5%, ± 10%, ± 20%, or ± 25% of the value specified. For example, "about 50" percent can in some embodiments carry a variation from 45 to 55 percent. For integer ranges, the term "about" can include one or two integers greater than and/or less than a recited integer at each end of the range. Unless indicated otherwise herein, the term "about" is intended to include values and ranges proximate to the recited range that are equivalent in terms of the functionality of the composition, or the embodiment.

[00185] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges recited herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof, as well as the individual values making up the range, particularly integer values. A recited range includes each specific value, integer, decimal, or identity within the range. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, or tenths. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc.

[00186] As will also be understood by one skilled in the art, all language such as "up to", "at least", "greater than", "less than", "more than", "or more", and the like, include the number recited and such terms refer to ranges that can be subsequently broken down into sub-ranges as discussed above. In the same manner, all ratios recited herein also include all sub-ratios falling within the broader ratio.

VIII. REFERENCES

[00187] All publications, patents and patent applications mentioned in this specification, and/or listed below, are indicative of the level of skill of those skilled in the art to which this invention pertains and are herein incorporated by reference to the same extent as if each individual publication, patent, or patent applications was specifically and individually indicated to be incorporated by reference. The reference numbers below correspond to reference numbers mentioned in the specification above.

[00188] [1] Masliyah, J. H.; Czarnecki, J.; Xu, Z. Handbook on Theory and Practice on

Bitumen Recovery from Athabasca Oil Sands. 2011.

[00189] [2] Lin, F.; Stoyanov, S. R.; Xu, Y. Recent Advances in Nonaqueous Extraction of

Bitumen from Mineable Oil Sands: A Review. Organic Process Research and Development. 2017. https://doi.org/10.1021/acs.oprd.6b00357.

[00190] [3] Nikakhtari, H.; Vagi, L.; Choi, P.; Liu, Q.; Gray, M. R. Solvent Screening for

Non-Aqueous Extraction of Alberta Oil Sands. Canadian Journal of Chemical Engineering 2013, 91 (6). https://doi.org/10.1002/cjce.21751.

[00191] [4] Nikakhtari, H.; Wolf, S.; Choi, P.; Liu, Q.; Gray, M. R. Migration of Fine Solids into Product Bitumen from Solvent Extraction of Alberta Oilsands. Energy and Fuels 2014, 28 (5). https://doi.org/10.1021/ef500021y.

[00192] [5] Pal, K.; Nogueira Branco, L. D. P.; Heintz, A.; Choi, P.; Liu, Q.; Seidl, P. R.;

Gray, M. R. Performance of Solvent Mixtures for Non-Aqueous Extraction of Alberta Oil Sands. Energy and Fuels 2015, 29 (4). https://doi.org/10.1021/ef502882c.

[00193] [6] Nikakhtari, H.; Pal, K.; Wolf, S.; Choi, P.; Liu, Q.; Gray, M. R. Solvent Removal from Cyclohexane-Extracted Oil Sands Gangue. Canadian Journal of Chemical Engineering 2016, 94 (3). https://doi.org/10.1002/cjce.22403. [00194] [7] Tan, X.; Vagi, L.; Liu, Q.; Choi, P.; Gray, M. R. Sorption Equilibrium and

Kinetics for Cyclohexane, Toluene, and Water on Athabasca Oil Sands Solids. Canadian Journal of Chemical Engineering 2016, 94 (2). https://doi.org/10.1002/cjce.22389.

[00195] [8] Renaud, R.; Pal, K.; WeiB, T.; Choi, P.; Liu, Q.; Gray, M. R. Vacuum Drying of Cyclohexane from Solvent-Extracted Oil Sands Gangue. Canadian Journal of Chemical Engineering 2017, 95 (3). https://doi.org/10.1002/cjce.22702.

[00196] [9] Panda, S.; Pal, K.; Merzara, S.; Gray, M. R.; Liu, Q.; Choi, P. Transport and

Removal of a Solvent in Porous Media in the Presence of Bitumen, a Highly Viscous Solute. Chemical Engineering Science 2017, 165. https://doi.Org/10.1016/j.ces.2017.03.006.

[00197] [10] Khalkhali, R.; Choi, P. Role of the Composition of Cyclohexane-Extracted

Gangue on Its Drying at Ambient Conditions. Canadian Journal of Chemical Engineering 2021. https://doi.org/10.1002/cjce.23964 (2021).

[00198] [11] Falciglia, P. P.; Roccaro, P.; Bonanno, L.; De Guidi, G.; Vagliasindi, F. G. A.;

Romano, S. A Review on the Microwave Heating as a Sustainable Technique for Environmental Remediation/Detoxification Applications. Renewable and Sustainable Energy Reviews 2018, 95, 147-170. https://doi.Org/10.1016/j.rser.2018.07.031.

[00199] [12] Jones, D. A.; Lelyveld, T. P.; Mavrofidis, S. D.; Kingman, S. W.; Miles, N. J.

Microwave Heating Applications in Environmental Engineering-a Review; 2002; Vol. 34.