Process for Separating Bitumen from Other Constituents in Mined, Bitumen Rich, Ore

Abstract

Separation of bitumen from mined ore employs cooling of the mined ore at a temperature where all the species contained in the ore become solid and brittle. Ore is maintained solid by appropriate continuous injection of cold air and/or carbon dioxide in the processing plant through the process. Difference in thermal expansion coefficient between bitumen and other ore species creates thermal stresses at interfaces of bitumen and other materials. The stresses favor separation of bitumen from other materials along species interfaces during comminution. The breaking of existing ore particles tends to occur at interfaces between different species, creating a mix of particles where bitumen particles are not aggregated with any other ore constituents such as ice or sand particles. The particles are maintained cold, loose and unattached. Ore particles are sorted and separated while still frozen in solid phase, creating a stream of frozen bitumen particles. The process is stopped when bitumen concentration is large enough for economical treatment by other bitumen existing processing techniques.

Description

[0001] This application claims the benefit of U.S. Provisional Application No. 61/328,667, filed Apr. 28, 2010, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Many heavy oil, bitumen minable deposits exist around the world where bitumen and heavy other hydrocarbons are mixed with various minerals and water. In North America, such deposits exist in the Athabasca region and are usually cased as "the Athabasca oil sands". Some of these deposits are shallow enough to be mined. Once the ore has been mined, the hydrocarbons need to be separated from the ore before receiving further treatment such as upgrading in order to transform the bitumen in marketable synthetic crude oil [SCO].

[0003] Many processes exist and are used to perform this extraction, but they all depend upon either mixing the ore with a warm fluid, water based most of the time, in order to perform this extraction, or using some solvent mixture to dissolve the bitumen and wash the ore from it.

[0004] A commonly used process is the so called warm water process. Its output is a bitumen froth whose concentration in mass is 60% bitumen and 30% water, and 10% water that carries the froth.

[0005] Other processes subsequently treat this product until commercial synthetic oil [SCO] is produced and sold. Some of the downsides of those processes are the demand they make on fresh water, their cost, their energy requirement and the amount of liquid toxic wastes they generate, known as tailing ponds in the industry. These facts are well known and well documented within the industry.

[0006] Problems exist and remained to be solved for recovering bitumen from ores. Needs exist for improved bitumen separation.

SUMMARY OF THE INVENTION

[0007] The invention described here is a new process that can replace the hot water or warm water processes currently used.

[0008] This new process requires less energy than the most commonly used warm water or hot water based processes, but most importantly requires no addition of water or any other liquid and does not create a stream of liquid waste. The new invention removes the need for tailing ponds.

[0009] This invention describes a new process that performs the separation of bitumen from mined ore without requiring the use of water or other products, solids or liquids.

[0010] This process take the mined ore, loosely crushed, coming from the mine site and separates bitumen from its other constituents. What comes out of the process is pure bitumen or bitumen with other impurities. The impurities are less than, no greater than or equivalent to those in the bitumen froth produced by the hot water or warm water processes. The results are something between pure bitumen and bitumen in froth that has been found to be the most cost efficient output of the process.

[0011] This invention describes a process of separation of bitumen from mined ore containing these bitumen.

[0012] This process is based upon cooling of the mined ore at a temperature where all the species contained in the ore become solid and brittle. Ore comminution is then performed on the ore while ore is maintained solid by appropriate continuous injection of cold air and/or carbon dioxide in the processing plant.

[0013] The ore pellets are broken in smaller parts. Because of difference in thermal expansion coefficient between bitumen and other ore species, thermal stress is created at interfaces of bitumen and other materials that favor separation of bitumen from other materials during the comminution process.

[0014] Indeed because of the effect of cold temperature on matter, the breaking of existing ore particles tends to occur at interfaces between different species, creating ultimately a mix of particles where bitumen is in a form of bitumen particles not aggregated with any other ore constituents such as ice or sand particles.

[0015] The ore particles are then sorted and separated while still frozen and in solid phase, creating ultimately as the main output of the process described in this application a stream of frozen bitumen particles. The process can also be stopped before pure bitumen is created, when bitumen concentration is large enough to be economically treatable by other existing processing technique, such as for example a paraffinic solvent unit.

[0016] When the required output quality is reached, constituents are allowed to warm or be warmed up to normal ambient temperature. Bitumen rich output is then sent to the next processing stage whatever it is, paraffinic solvent unit, upgrader, in order to receive further treatment, while the leftover species are disposed of as wastes.

[0017] The process described and claimed in this application does not require mixing ore with water or any other liquid such as solvent.

[0018] This is a main feature of the invention. The process replaces the currently used warm water extraction process for mined oil sands.

[0019] The invention uses cold engineering. A state of the art cold plant is required to provide the process with cold air and/or liquid carbon dioxide with optimized energy efficiency. The frozen ore is then processed using comminution or size reduction techniques. Contrary to their traditional use, these techniques are chosen and particles are sized in order to maximize phase separation between bitumen and other species, while minimizing sand grain size reduction, followed by state of the art powder handling and classification.

[0020] When bitumen has been liberated from the sand grains a complex powder mix is constituted, and effective separation of the species needs to be performed. The powder mix created is very cohesive, in the sense that individual particles tend to stick to each other, creating particle aggregates that behave like bigger complex particles. The reason for this is that some particle-particle interactions, such as for example the Van der Walls force, are much greater than the weight of these small particles. Various classifications of technology exist and can be used in the context of a multiple step process, where each one targets the removal of a specific kind of waste from the ore stream. The process is organized so that the easiest particles to remove are removed first, allowing for further work to be performed on a more concentrated ore stream.

[0021] The invention is based upon the integrated combination of three different functions without the use of any water or solvent through the processing chain in order to remove enough minerals matter as well some water from the processed ore stream to produce as a result a product whose purity is at least comparable to the output of the warm water process. Additionally the rejected waste stream can be further treated in the same manner as the main bitumen rich ore stream in order to remove residual bitumen left over from the waste before the waste is finally rejected from the process. This is done using the same process but with technological implementations optimized for the composition of each ore or waste stream.

[0022] The initial input of the processing chain is mined oil sand ore that has been prepared after removal of the biggest mineral rocks of a few cm diameters in size or greater. The ore is put in crusher and precooled at ambient air temperature. This temperature is not constant and varies depending upon seasons and local weather conditions. The precooling is done by forcing ambient air to flow through the ore during this crushing stage. In the event that the mined ore temperature is colder than ambient air the preliminary crushing is performed without forced air injection in order not to warm the ore.

[0023] Depending upon the specifics of each implementation of the process, cooling gas from the refrigeration plant can also be used at that preliminary crushing stage.

[0024] The particle size of the ore at the end of this preparatory stage is temperature dependent, the colder the temperature the smaller the ore particle size.

[0025] Once the ore has been prepared, it is introduced in the main processing chain and further cooled and crushed in such a way that it remains loose during the cooling and crushing process. This is done in a mill that is for example a ball mill through which cooling agent is forced. Cooling and separating is achieved for example by making sure the ore is agitated enough during the cooling process so that existing ore pellets cannot aggregate into bigger particles during the cooling process. The ore from the mine is cooled in a crusher that reduces the size of the pellets while they are cooled through this cooling phase. Water existing within the ore need to be turned into ice. The bitumen needs to be cooled below the Fraass fragility point or glass transition temperature T_g to become hard, solid and brittle.

[0026] This temperature threshold varies with each bitumen chemical composition but is usually in a range between approximately -30° C. up to -5° C.

[0027] Accordingly, the operating temperature for the process described here is below the glass transition temperature of the processed bitumen. The operating temperature range, below T_g, is determined as part of the process cost efficiency/optimization.

[0028] Indeed, in order to globally optimize the process, the ore can be cooled further below its transition temperature to take advantage of the thermal expansion coefficient differences between heavy hydrocarbons and the rest of the species present in the ore as well as of the increased brittleness of bitumen with decreasing temperature. Because of the thermal expansion differences, cooling below the temperature where hydrocarbons become solid and brittle creates thermal stresses at the interfaces between the hydrocarbons and the rest of the are materials, facilitating phase liberation from each other. Hydrocarbons contract much more than minerals or ice under cooling.

[0029] Cooling is obtained either by using cold air or solid or pressurized liquid or gaseous carbon dioxide or a combination of both. Liquid nitrogen can be also used, but it is more expensive.

[0030] During reducing the particle size through comminution, particle size of the ore is reduced, and the number of particles increases accordingly. Some of these reduced size particles have a greater bitumen mass fraction. Comminution can be ensured through various devices from crushers at the beginning of the process to prepare the mined ore before cooling starts. When the particle sizes decrease and the species get more and more separated, the ore stream can be aerated for further treatment. Mills or jet milling devices, for example, are used for further and finer comminution. Gas driven classifying machine, such as cyclone or forced vortex classification machines are used as well.

[0031] Also it is useful to separate the ore into different streams by particle sizes in order to perform comminution separately on each stream. In those cases the comminution parameters and technology are independently optimized for each ore stream. For example coarser particles are treated further in tumblers, while finer particles are aerated and treated in an aerosol form in a jet mill and air classifying machine. Ore is transferred from one stream to another once its properties have evolved.

[0032] Stream separation is achieved by passing initial streams through a screen and treating the streams in parallel but with different machines the particles that pass through and the particles that do not pass through the screen. The screen is washed with high pressure cold gas jets, whose velocity is high enough to separate aggregated particles from each other, and accordingly cleaning coarser particles from smaller one sticking to them.

[0033] In the cooling phase description, an important feature of the described process is that because of the significant difference of thermal expansion between bitumen on the one hand and ice and most minerals on the other, the breaking of the particles during the comminution phase will occur preferentially at interface planes. This preferentiality will be larger with decreasing temperature and increasing thermally induced stresses. For each deposit, a very important step for the optimization of the process is finding the highest operating temperature or, more exactly, temperature range through the chain of crushing/sorting stations, where this difference of thermal expansion effect is large enough to fully separate the bitumen particle from the rest of the ore. During the various steps of comminution the thermally induced stress helps by making complex particles made of bitumen and other constituents split and break preferentially along the thermally stressed interfaces, freeing bitumen particulates from the rest of the ore.

[0034] The amount of thermal stress created of course increases the energy requirements and the cost of cooling but will decrease the cost of comminution. Determining how much cooling is best is part of building a plant based upon a specific deposit and ambient condition.

[0035] Toward the end of the process, when the size of the particulates has been reduced enough, most if not all of the bitumen is present in the form of a bitumen powder mixed with other ore constituents powders, such as ice crystals and fine mineral particles.

[0036] Separating the various species when the ore is a mixture of fine particle, bitumen being in the form of a pure bitumen powder needs to be done while making sure that the ore remains cold enough to be solid and loose, if necessary by injecting more cold gas or liquid carbon dioxide. The separating is to be performed in several steps along the process chain between various comminution stations in order to remove waste particle that can be separated from the ore as early as possible, as a consequence of the change in properties of the ore induced by the previously performed comminution step.

[0037] Each separation station provides as its output an ore with a higher bitumen mass fraction compared to the ore at the input of the station.

[0038] Each separation and sorting station uses an optimized principle and technology targeting the specific wastes to be removed.

[0039] For example, sieves or screens are used initially at the beginning, to remove coarser particles. Multiple stages of gas classification machines such as cyclones and forced vortex machines follow in later stages.

[0040] Once the limit of air classification to remove mineral particles has been reached for removing wastes from the ore stream, additional technology is put into play such as for example electrostatic precipitators as well as other separators, depending upon other discriminating properties between these species, such as for example, surface adhesive properties or electrical conductivity of the species. Pure bitumen powder is the final and ultimate output of the new process described herein, all the other ore constituents having been eliminated, one by one through the various stations of the process.

[0041] The three functions will be applied sequentially or simultaneously as well as repetitively using different devices or technologies in order to adjust to the variation in ore characteristics.

[0042] This invention allows efficient control of ore temperature such as decreasing ore body temperature with decreasing particle size, and at the same time increasing purity of the separated species.

[0043] Because tar sand is a natural material and has properties that significantly vary from deposit to deposit, each implementation uses specific operating parameters while keeping the fundamental principles of the invention of solid crushing and sorting of pure mined ore brought down to a temperature low enough so that such treatment become possible and selectively removing wastes along the process.

[0044] The powder mix contains very small particles, whose size is smaller than one micron along with coarser particles. The bitumen is part of the finest particle species in the ore, along with ice particles and very small mineral particles, usually clay, called fines in the industry.

[0045] The new process described in this application allows for a large range of practical implementations, on a continuous flow of ore or in batch mode treatment as well for some specific needs. Each project employs specific implementation, depending upon ore conditions and requirements, but the new process always is articulated around following three actions detailed above applied upon the extracted ore as part of the described process.

[0046] The innovative process described herein resides in a combination of steps to separate bitumen from all other non-bitumen species present in the ore after the bitumen has been made solid, brittle and thermally stressed while going through the cooling process.

[0047] The combination enriches the processed ore stream by removing specific wastes one after the other until the required output concentration or purity is achieved.

[0048] Because of the thermo-physical properties of these materials at low temperatures the bitumen becomes a brittle solid and then contracts much more than water or other minerals because its thermal expansion coefficient is larger than that of water or silica.

[0049] The ore also contains fine minerals, such as clays. They are either freed and treated as independent mineral particles as part of the process, or remain trapped in the species that contains them. The fine materials such as clays are very dominantly contained in water which becomes ice particles. Whatever impurities are present in the bitumen, whether dissolved or included with sizes smaller than the bitumen powder final size, are not affected by the process described herein and remain included in the bitumen powder, and are not removed by the use of the process. Those small inclusions, if any, have to be dealt with subsequently.

[0050] The process uses several steps made of the following three independent actions that can be used together or one after the other or a combination of both, under various implementations, as part of the process: cooling of the ore while keeping it agitated enough so that it remains loose and the particle size does not increase during the process, crushing the ore in order to liberate bitumen from other materials present in the ore while it is cold so that bitumen and all other constituents are and remain solids and brittle through the operation, and separating the materials while they are still cold enough so that they remain frozen, solid and loose during the separation. The ore can be cooled even more below the temperature where the hydrocarbon become frozen and brittle in order to create and subsequently take advantage of thermally induced stress at the interfaces of these hydrocarbons with other materials. These thermally induced stresses facilitate the shattering process of the ore grains at the interface of bitumen and other materials.

[0051] The crushing and separation are performed several times, each time selecting the separation from the ore of a specific waste material, either some mineral, selected by size, typically above a certain cutoff size set differently for each separation station, decreasing along the processing chain, or nature or ice. The ore is cooled with injection of cooled liquid carbon dioxide where the liquid carbon dioxide transforms itself upon release in the ore processing chain from a part in gas for part in carbon dioxide ice.

[0052] The carbon dioxide ice is further mixed with the ore before its sublimation occurs. The ore could also be cooled with refrigerated air.

[0053] The ore could similarly be cooled with a mixture of cold air and liquid carbon dioxide where the liquid carbon dioxide transform itself upon release in the ore processing chain for a part in gas for part in carbon dioxide ice.

[0054] The carbon dioxide ice is further naturally mixed with the ore before its sublimation occurs. The ore also is cooled with refrigerated air.

[0055] The ore is separated by grain size in two or more independent streams that can be treated separately for bitumen liberation. The gas expansion resulting from the heat transferred from the ore to the cooling gas is used as a mechanical driver to work on the ore stream itself.

[0056] The crushing is controlled to separate bitumen from grains, while minimizing the crushing of sand grains and other mineral material. Cooling and agitating the ore thereby prevent particle sizes from aggregating and maintain the ore in loose condition. Freezing the particles makes the particles brittle.

[0057] Further cooling takes the ore below the temperature where the bitumen particles and hydrocarbon particles become frozen and brittle. Crushing the ore and separating fine bitumen and hydrocarbon particles from larger particles frees and separates fine bitumen and hydrocarbon particles from larger particles of other materials present in the ore.

[0058] These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG. 1 is a flow chart of steps in purifying bitumen from ore taken from a mine.

[0060] FIG. 2 is a flow chart of a cold plant and cold distribution for the ore processing.

[0061] FIG. 3 shows steps in the separation of bitumen from ore.

DETAILED DESCRIPTION OF THE DRAWINGS

[0062] Without limitation, and in order to allow to someone skilled in the art to implement and optimize the process described in this application for a specific project, the following examples illustrate practical implementation where the elementary elements of the process are used several times, each time through the use of a different technology, in order to reach gradually pure bitumen powder. Again this is just as an example of implementation. It must be stated that all the specifics described in this section are relevant to the described example but are not limiting to the process implementation. The example described in this section is illustrated in the attached flowcharts.

[0063] Referring to FIGS. 1 and 2, in step 1 the ore 11 arrives from the mine and is prepared in a way similar than what is done for the warm water extraction process. The biggest rocks are removed 13, and the remaining ore is crushed to have a granular size not exceeding ˜2 mm. Depending upon the circumstances, and the time of the year, or under operator control as shown in FIG. 2, the ore might or might not be precooled during this step 1 stage. The cold process gas is returned through insulated line 141 to step 2A to pre-chill the ore in step 2A. Cold gas 111 from step 2 in station 102 circulates through station 101 and step 1 before the gas flows 113 back to the cold plant 100. Cold ambient air may be circulated through station 101 in step 1. Ambient air or cooling gas can be forced through the ore during this stage.

[0064] In step 2, the ore 21 is then transferred to a set of two closed tumbler mills in stations 102A and B for step 2 where in and out of gas are controlled and where the ore is further lightly crushed and start to be cooled to its operating temperature by injection 121 of cold gas from the cold plant 100. The criteria for exiting station 102 is particle size smaller than 500 μm. Ore output is performed through an integrated vibrating screen 25.

[0065] No rejection is planned at this stage, but rejection 23 is used if single rocks bigger than 500 μm and smaller than 2 mm are present in the ore in significant amount. Otherwise they will ultimately be reduced and passed through. Ore output 31 temperature is what it needed to keep grains loose without reagglomeration, for example in the -5 to -15° C. range. The temperature needs to be monitored. When atmospherically possible, this station 102 is air cooled with forced ambient air.

[0066] Regarding cooling gas management around step 2 in station 102, two options exist and are used depending upon circumstances.

[0067] a) Cooling gas 141 is flowed back through step 2 and then Step 1 in station 101 where the gas precools initial ore before being either released or recycled depending upon the specifics of the cooling system and of the gas, air, CO2, summer, winter . . .

[0068] b) When outside temperature is cold enough atmospheric air is used to cool 101, 201a and possibly 201b allowing for additional energy saving during winter time.

[0069] Transient time through the step 2 and station 102 will depend upon temperature gradient but should not exceed 2-3 minutes at most. During this stage in step 2 all water included in the ore is turned into ice. The kinetic of this transition drives the time through this station. The ore at this point is in bulk with ambient/air and or cooling gas forced through it while it is crushed. Its output characteristics are:

[0070] Mass in=mass out

[0071] Temperature is unknown and is not critically important as long as

[0072] a) all water is turned into ice, and

[0073] b) the granular materials are properly aerated and vibrated, and granules do not re-agglomerate throughout treatment and transition toward the next step.

[0074] It is expected that the corresponding ad-hoc temperature, driven by physical requirements, such as salt concentration in the water as well as specific bitumen surface adhesive properties as a function of temperature, will be in the range -15° C. to -5° C.

[0075] In step 3, the ore 31 arriving from step 2 in station 102, with a fraction of the gas is subsequently tumbled and crushed while the crushed ore is cooled down further as needed through cooling agent injection 115. At the exit 35 of this stage the crushed ore temperature must be below bitumen glass transition temperature.

[0076] Cooling of the ore and liberating bitumen drives treatment time during this step.

[0077] The exit 35 of step 3 is through a ˜150 μm vibrating and aerated splitting screen 37 as seen as a one pass step with no feed back loop provided. If needed, a two steps screen is provided to reinsert the particles above 300 μm in size in the tumbling mill 103.

[0078] This screen separates the ore stream in two parts. The coarse part that is noted C, and the fine part is further noted F. Most of the gas is directed with the fines F where the cold gas is more useful. This is also implied by the use of cooling gas for washing as much fines F as possible from the coarse C through the splitting screen 37. The gas mass flow rate must be also compatible with the ore mass flow rate through the screen 37, so there is no great flexibility at this stage for tuning the gas velocity.

[0079] From this point forward, the coarse C and fine F streams are treated differently.

[0080] In step 4-C, the coarse part is sent to another tumbler 104C with a slightly lighter action than the previous one 103. Cold gas is injected to maintain low operating temperature. The amount of cooling cannot be larger than the mechanical energy spent on the ore. Because this ore stream C is made mostly of coarse sand grain with some non-liberated bitumen, the liberation of bitumen is very efficient. The particles being coarser and not surrounded by much small articles, liberating bitumen from them is a more efficient process, while it is important to avoid breaking sand grains as much as possible.

[0081] Smaller particles, fines, bitumen and ice liberated by the process are extracted through a tightly coupled classification in step 4-C and are sent 41 toward the fine stream input to step 4-F. Remaining coarse particles exit the process after a given time and are rejected as waste after a real time controlling unit has ensured that bitumen residual is less than an established threshold. Failing control means reinjection of particles with residual bitumen toward the entrance of step 4C. Very little residual bitumen will remain associated with these coarse particles once properly washed with cold gas.

[0082] Step 4 C ensures that minimal size reduction for the coarse grain and minimum rejection rate.

[0083] Tuning parameters in step 4-C are intensity of the tumbling, average pass through time in the tumbling station and classification parameters to extract fine particles, including gas velocity and size of the classifying machine.

[0084] The classification first includes a cold gas washed vibrating screen followed for the fine section by a "zigzag impactor" or another dispersive machine in order to break aggregates, followed by a cyclone or another air classification machine. There is plenty of energy available in the gas stream to power the zigzag impactor and a cyclone separator, should this technological option be selected as well as to clean the screen. The waste 47 being rejected is comprised of the coarse section from the screen and the coarse section from the cyclone.

[0085] The output gas stream 41 from step 4-C along with the fines F passed through the splitting screen 37 after step 3 are then injected at the input of Step 4-F.

[0086] This transition requires injectors that inject the ore and cold gas in the aerated part of the process plant that will continue from here until the end. From this point forward mass loading ratio between injected ore and cold gas must be controlled, because classifications performance depends upon it.

[0087] In step 4-F, the fine stream is aerated and carried away 51 from that point forward with a relatively high velocity. This velocity is permitted by the fact that the particles are small enough to have minimal erosion effect. This fact must be enhanced by the plant construction that minimizes these impacts or focuses them on areas designed to be easy to maintain, replace or reline.

[0088] The input stream is first passed through another jet mill machine whose purpose again is to break aggregate and also to incidentally liberate residual bitumen through impacts against the plates before entering the next array of classification machines. This is done just before the classification machine so that aggregates don't have the time to reform before being classified.

[0089] The warming up of the cold gas through the heat transfer from the ore to the gas provides the energy to move the stream of gas and ore through the various machines of this step.

[0090] The coarse section exiting from these cyclones is further aerated and injected through another jet mill and another set of classification machines. The waste stream exiting is then disregarded as wastes while the fine section is mixed with the fine section from the first battery of classification machines and is sent toward the next step.

[0091] This is made to ensure high quality of bitumen extraction and optimal use of mechanical energy available in the stream due to heat transfer from ore to gas as well as minimizing the requirements and constraint upon the next step that will be more costly.

[0092] In step 5, a high energy gas-forced vortex gas classification is performed after fully energizing the media to break particle agglomerates.

[0093] The output quality and efficiency of this step depends upon the exact size distribution of the fines compared to water and bitumen. Most, if not all mineral particles above 1 or 2 microns can be removed at this stage.

[0094] The fines and cold gas flow to the high energy forced vortex 105 in step 5 and are impacted to break apart agglomerates and send 61 larger particles for classification 107. Larger mineral particles are rejected 63, and fines are returned 65 to the input 51 of step 5.

[0095] The output product 70 of step 5 is made of initial bitumen and water, with the extraction efficiency of the process along with the residual fines that are smaller than ˜1-2 microns at most as well as the ones that might be trapped in the ice. The corresponding amounts of mineral will be, at most, the amount of mineral of initial size smaller than the cutoff size mentioned present in the ore.

[0096] Further product purification, possibly until pure bitumen is produced, is performed afterward to remove these fines as well as ice particles, using for example electrostatic separators to remove those residual particles. In such a final electrostatic stage 107 water and mineral fines are removed 73 and the final bitumen output 65 is separated.

[0097] The flow diagrams summarize the process implementation as described.

[0098] As shown in FIG. 2, the cold gas plant 100 injects cold gas into several parts of the system to cool the ore stream and subsequently control its temperature or adjusting mass loading ratio of ore mass over gas mass in the processing stream where needed. Secondary functions are performed by this cold gas such as for example washing coarse particle from fines when needed or intermittently cleaning vibrating screens as explained above. The flow diagrams summarize the process implementation as described.

[0099] The cold plant 100 injects 121 cold gas into initial cooling and crushing step 2 for initial cooling of the prepared ore. The cold plant 100 also injects 115 cold gas into the main inflow line 113 of the initially crushed and cooled material flowing into the main cooling and crushing step 3. The cold gas injection through line 115 further reduces the temperature of the initially crushed and cooled ore and entrains the materials into the main crushing and cooling step 3. As the cold gas imparts cooling to the materials, the gas temperature and volume rises for driving the cold crushed materials into splitting screen 37. The cold gas flows 35 with the particles into screen 37. The majority of the cold gas flows 123 with the fines F from the screen to step 4-F. A lesser amount of the cold gas flows 125 with coarser particles C to step 4-C and back 127 to step 4-F. Cold gas is injected 131 into step 4-F. The cold gas flows 133 with the bitumen particles and ice particles to step 5, where additional cold gas is injected 135. Cold gas flows 137 with particles to step 5-C and returns 139 to the return gas flow 141 to reduce temperatures to keep particles loose in a first part of step 2. From step 2 the spent cold gas flows 111 to step 1 for cooling and loosening the ore preparation. From step 1 the used and warmed cold gas returns 112 to the cold plant 100. The cold gas is cold air or air mixed with CO₂ snow particles, gaseous CO₂, nitrogen or any other gas or cold gas producing product.

[0100] As shown in FIG. 3, where cooling gas is assumed to be air for illustrative purpose, loosely crushed and presorted mined ore 301 arrives from a mining site at ambient temperature. The arriving ore is loose and coarse, and the particulate size is in the range 5 mm-1 cm. If necessary, a preliminary crushing is performed at the entrance of the process to reach the desired size. The control of the particle size at the process input is useful in order to control the cooling phase duration. The finer the particles the faster the cooling will occur, everything else being equal.

[0101] Ore 301 is then fed to the first cooling device 303, where it is mixed with cold air 305 from the cooling plant 100 or from outside air when outside temperature allows for it, while the ore is agitated. This can be achieved either in a rotary drum or in a pipe with an air flow and air pressure large enough to ensure that the ore particles are fully aerated and cooled through forced convection, and are not allowed to aggregate into bigger particles while they freeze. The final temperature before leaving device 303 is slightly below the glass transition temperature, usually -30° C. or less.

[0102] Once the desired low temperature is reached, the ore is sent 307 to a comminution and gas blasting station 311 where the ore is crushed to particulates slightly below average sand grain size. The size depends on the deposit, but usually will be ˜100-200 micrometer. As much as is possible and realistic, the crushing is gentle enough not to break sand grains. Air 313 flows into station 311.

[0103] In blasting comminution station 311 frozen and thermally stressed ore particles are projected against a hard wall or against each other at a controlled average speed with cold air as a carrier. The output of station 311 is large sand grains freed from bitumen and particles, surrounded by a fine layer of ice and other particles made of bitumen and other constituents whose size are typically smaller than 150 micrometers.

[0104] This ore is then fed 315 to the first separating station 317 made of sieves and/or screens that remove the loose sand grains whose size exceeds 1 mm to waste 319.

[0105] The remaining ore 321 is subsequently cooled in station 323 to a lower temperature, possibly as cold as -50 C or -40 C if needed in order to increase the thermal stress effect and facilitate bitumen release in subsequent comminution.

[0106] The cold particles 325 are sent to a finer comminution station 327 whose output average size is 5 to 10 times smaller than its input size. This is achieved, for example, with the use of mills. The average size of the particles at the output 325 is ˜10 microns-20 microns or less. Very few bigger particles are present.

[0107] Cold air 330 is delivered to further cool and maintain looseness the materials in each station. In this illustrative example, the next sorting station 323 discriminates by density, separating minerals particulates 325 with a density usually above 2 g/cc from ice crystals and bitumen particles 337, both with a density close to 1 g/cc.

[0108] The output of station 333 is void of minerals except from those trapped in the ice particles and possibly bitumen. The bitumen is rather pure of minerals, even fine ones, at this stage. Depending upon the requirement of the final separating steps that separates ice from hydrocarbons, the remaining ore is reduced even more in size, if that is necessary, through the use of another cooling station 341, feeding 343 another milling and comminution station 345.

[0109] The final separation station 351 separates bitumen particulates from water ice using properties discriminating between these particles. For example, an electrostatic separator uses the differences in conductivity between ice and bitumen, or a separator using the difference in surface properties, such as friction or adhesive strength, discriminates between these species. The output of stage 351 is waste 353 and separated pure bitumen powder 355, ready to be warmed and sent toward the next step of its treatment chain, before commercialization. From this point forward, the temperature of the bitumen powder is no longer important, and its control stops accordingly.

[0110] The various coolings of the ore and the necessary control of the temperatures during the process, from beginning to end, will be ensured by cold gas. A cold gas generator 100 is a significant part of the extraction plant based upon this process and is also the most significant energy user of this process. For ore deposits where cold winter temperatures prevail, energy demand will be vastly reduced in winter, owing to the advantage of the naturally cold temperature of the available air. Cold gas, possibly at various temperatures, will be distributed from the plant through the full ore treatment chain that will use the process for bitumen extraction in order to ensure that ore temperature is what it needs to be at each step of the process. The cold air also provides the required agitating motions that ensure the ore remains loose and prevented from aggregating during the whole process.

[0111] While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention, which is defined in the following claims.

Claims

1. A process for separating bitumen and other hydrocarbons from mined ore that contains these hydrocarbons, based upon the applications of one of several steps made of the following three independent actions that can be used together or one after the other or a combination of both, under various implementations, as part of the process cooling of the ore while keeping it agitated enough so that it remains loose and the particle size does not increase during the process. crushing the ore in order to separate bitumen from other materials present in the ore while it is cold so that bitumen and all other constituents are and remain solids and brittle through the operation. separating the materials while they are still cold enough so that they remain frozen, solid and loose during the separation

2. The process as described in 1 where the ore is cooled even more below the temperature where the hydrocarbon become frozen and brittle in order to create and subsequently take advantage of thermally induced stress at the interfaces of these hydrocarbons with other materials. These thermally induced stresses facilitate the shattering process of the ore grains at the interface of bitumen and other materials.

3. The process as described in 1 where the crushing and separation are performed several times, each time selecting the separation from the ore of a specific waste material, either a special kind of mineral particles or ice, targeting various kinds of waste materials using different technologies or settings through the various separation stations deployed along the process.

4. The process claimed in 1 where the ore is cooled with injection of cooled liquid carbon dioxide where the liquid carbon dioxide transforms itself upon release in the ore processing chain for a part in gas for part in carbon dioxide ice.

5. The process claimed in 4 where the carbon dioxide ice is further mixed with the ore before sublimation of the carbon dioxide occurs.

6. The process claimed in 1 where the ore is cooled with refrigerated air.

7. The process claimed in 1 where the ore is cooled with a mixture of cold air and liquid carbon dioxide where the liquid carbon dioxide transforms itself upon release in the ore processing chain for a part in gas for part in carbon dioxide ice.

8. The process claimed in 7 where the carbon dioxide ice is further mixed with the ore before its sublimation occurs.

9. The process claimed in 1 where the ore is separated by grains size in two or more independent streams that are treated separately for bitumen liberation.

10. The process of claim 9, further comprising separating wastes particles from valuable ones while keeping the particles cold to prevent unwanted properties change induced by warming up of the particles.

11. The process claimed in 1 where the gas expansion resulting from the heat transferred from the ore to the cooling gas is used as a mechanical driver to work on the ore stream itself.

12. The process claimed in 1 where the crushing is controlled to liberate bitumen from grains while minimizing the crushing of sand grains and other mineral material.

13. A process comprising separating bitumen and hydrocarbons from mined ore that contains the bitumen or other hydrocarbons, further comprising cooling and agitating the ore and thereby preventing particle sizes from re-agglomeration and maintaining the ore in loose condition, freezing the particles and making the particles brittle, crushing the brittle particles and separating fine bitumen or other hydrocarbons particles from larger particles of other materials present in the ore by size, density, shape, electric properties or other surface properties.

14. The process of claim 13, further comprising separating semi solid or fluid valuable material from ore by cooling and aerating particles of the ore, loosening the particles, screening the particles and removing sand grains as waste, cooling and aerating loosened and screened particles to a lower temperature milling the cooled aerated and screened particles separating dense particles from light particles and separating and recovering valuable material powders from the lighter particles.

15. The process of claim 14, wherein the first cooling and aerating comprises lowering temperatures of the particles below a freezing point of water.

16. The process of claim 14, wherein the first cooling and aerating comprises lowering temperatures of the particles below a material glass transition temperature.

17. The process of claim 16, wherein the loosening comprises entraining the particles in gas jets and impacting the particles against each other or against a solid surface.

18. The process of claim 17, wherein the screening separates coarse mineral particles separated as waste and finer particles are retained and sent to the next processing station.

19. The process of claim 14, wherein the processing comprises rotating the ore particles in drains while flowing cold gas through the particles.

20. The process of claim 14, further comprising further cooling and aerating the lighter particles and further milling the cooled and aerated lighter particles before the separating and recovering the valuable material powders.

21. The process of claim 20 further comprising separating wastes particles from valuable ones while keeping the particles cold to prevent unwanted properties change induced by warming up of the particles

22. Apparatus comprising an ore intake, ore preparation crushers and coolers connected to the ore intake, a first cooler and loosener connected to the ore intake, an ore particle breaker connected to the cooler and aerator, a second cooler connected to the ore breaker, an ore particle crasher connected to the second cooler, a particle separator connected to the second cooler, separating coarse particles as waste from finer particles, a particle separator receiving the finer particles and separating the final particles by differentiated surface attraction, adhesion composition, shape, electric properties or density.

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