CA3060461A1 - Sodium silicate and caustic in combination as process aids for the extraction of bitumen from mined oil sands - Google Patents

Abstract

, ABSTRACT
A process for extracting bitumen from an oil sand ore is provided, comprising mixing the oil sand ore with heated water to form an oil sand slurry; conditioning the oil sand slurry to form a conditioned oil sand slurry; introducing a dosage of sodium silicate and caustic to the process either prior to or during the mixing step, or prior to or during the conditioning step, or both; and introducing the conditioned oil sand slurry into a separation zone to form a bitumen froth and tailings.
)CA 3060461 2019-10-281 18

Description

SODIUM SILICATE AND CAUSTIC IN COMBINATION AS PROCESS AIDS FOR
THE EXTRACTION OF BITUMEN FROM MINED OIL SANDS
FIELD OF THE INVENTION
The present invention relates generally to a water-based process of extracting bitumen from oil sand ores by adding a combination of sodium silicate and caustic (sodium hydroxide) to improve the performance of water-based bitumen extraction.
BACKGROUND OF THE INVENTION
Oil sand generally comprises water-wet sand grains held together by a matrix of viscous heavy oil or bitumen. Bitumen is a complex and viscous mixture of large or heavy hydrocarbon molecules. The Athabasca oil sand deposits may be efficiently extracted by surface mining which involves shovel-and-truck operations. The mined oil sand is trucked to crushing stations for size reduction, and fed into slurry preparation units where hot water and caustic (sodium hydroxide) are added to form an oil sand slurry.
The oil sand slurry may be further conditioned by transporting it using a hydrotransport pipeline to a primary separation vessel (PSV) where the conditioned slurry is allowed to separate under quiescent conditions for a prescribed retention period into a top layer of bitumen froth, a middle layer of middlings (i.e., warm water, fines, residual bitumen), and a bottom layer of coarse tailings (i.e., warm water, coarse solids, residual bitumen).
The bitumen froth, middlings and tailings are separately withdrawn. The bitumen froth is de-aerated, heated, and treated to produce diluted bitumen which is further processed to produce synthetic crude oil and other valuable commodities.
Caustic (sodium hydroxide) has been used as a process aid in water-based bitumen extraction processes from the beginning of the industry. It plays many important roles in bitumen extraction, such as it promotes the release of natural surfactants from bitumen to the aqueous phase, precipitates divalent cations such as calcium and magnesium, modifies the electrical surface potential of bitumen and solids, adjusts the pH, and makes solids more hydrophilic, leading to better bitumen-solids separation.
However, when processing problem ores, such as low-grade, high-fines ores, a high caustic dosage is often needed. "Problem ores" are oil sand ores generally having low bitumen content (about 6 to about 10 wt%) and/or high fines content (greater than about 30 wt%). "Fines" are defined as particles such as fine quartz and other heavy minerals, colloidal clay or silt generally having any dimension less than about 44 pm.
In some cases (e.g., processing ores with the use of high salinity process water), even a very high dosage of caustic is not able to sufficiently improve the ore processability.
In addition, high caustic dosages may cause problems such as bitumen emulsification, which impairs froth treatment, and difficulties in tailings settling. Further, caustic is toxic and corrosive, impacting health and the environment and causing scaling on equipment due to precipitation of divalent cations when it is added to the slurry water for slurry preparation. Thus, using high dosages of caustic is not desirable. Alternative process aids or other ways to process these problem ores must be developed. A great number of studies have been conducted to find alternative process aids to replace caustic or to reduce the amount of caustic used in the extraction process. None of the chemicals tested as a caustic replacement was as effective and/or economic as caustic.
Due to these problems, it is desirable to reduce the amount of caustic used by supplementing caustic with another chemical or process aid.
SUMMARY OF THE INVENTION
The current application is directed to a water-based process of extracting bitumen from mined oil sand ores by combining sodium silicate with reduced amounts of caustic to condition the oil sand slurry. It was surprisingly discovered that by conducting the process of the present invention, one or more of the following benefits may be realized:
(1) A combination of sodium silicate and caustic at the same dosage as caustic alone improves bitumen recovery and froth quality when processing problem ores, showing a strong synergy between sodium silicate and caustic.
VcA 3060461 2019-10-28 2 ' ,

(2) The combined use of sodium silicate and caustic requires a lower amount of total chemical addition than the use of caustic alone, and was more effective at much lower dosages than caustic alone.

(3) The combined use of sodium silicate and caustic minimizes the amount of caustic, negating problems normally encountered by use of high caustic dosages.
Thus, use of the present invention may conserve the amounts of process aids used in bitumen extraction and improve bitumen recovery and froth quality.
As used herein, wt% and % are used interchangeably and it is understood that all percentages herein are wt%, e.g., wt% of the oil sand ore being processed.
In one aspect, a water-based process of extracting bitumen from oil sand ore is provided, comprising:
= determining a dosage (wt%) of caustic necessary to maximize the bitumen recovery for the oil sand ore to be processed when using caustic alone as a process aid;
= determining an amount of caustic (wt%) and an amount of sodium silicate (wt%) which yield substantially the same bitumen recovery or greater than when using caustic alone;
= mixing the oil sand ore with heated water to produce an oil sand slurry;
and = adding the amounts of caustic (wt%) and sodium silicate (wt%) before, during or after mixing the oil sand ore with heated water to condition the oil sand slurry and to improve bitumen recovery from the oil sand ore;

= wherein the sum of the amounts of caustic (wt%) and sodium silicate (wt%) is equal to or less than the dosage (wt%) of caustic alone.
In one embodiment, the amount of caustic ranges from about 0.01 wt% to less than 0.1 wt% of oil sand ore. In one embodiment, the amount of sodium silicate ranges from about 0.003 wt% to about 0.05 wt% of oil sand ore. In one embodiment, the oil sand ore is poor processing ore having a bitumen content of about 6 to about 10% or a fines content greater than about 25% or both.
In one embodiment, when the bitumen content of the oil sand ore ranges from about 6 wt% to about 10 wt% and the fines content of the oil sand ore is greater than about 25 wt%, the amount of caustic is about 0.01 wt% to about 0.03 wt% of the oil sand ore. In one embodiment, the amount of sodium silicate ranges from about 0.003 wt% to about 0.03 wt% of the oil sand ore.
In one embodiment, the caustic is sodium hydroxide.
In one embodiment, the sodium silicate has a Si02:Na20 ratio in the range of 0.5 to 3.22.
DESCRIPTION OF THE DRAWINGS
Referring to the drawings wherein like reference numerals indicate similar parts throughout the several views, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein:
FIG. 1 is a schematic showing, in general, the water-based process for extracting bitumen from mined oil sand ore.
FIG. 2A is a graph showing primary bitumen recovery (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AR.
FIG. 2B is a graph showing the combined bitumen recovery (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AR.
VCA 3060461 2019-10:28 4 FIG. 3A is a graph showing primary froth bitumen content (cY0) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AR.
FIG. 3B is a graph showing primary froth water content (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AR.
FIG. 4A is a graph showing primary bitumen recovery (%) as a function of dosage ( /0) using caustic alone or in combination with sodium silicate for poor oil sand AD.
FIG. 4B is a graph showing the combined bitumen recovery ( /0) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AD.
FIG. 5A is a graph showing primary froth bitumen content (Y()) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AD.
FIG. 5B is a graph showing primary froth water content (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AD.
FIG. 6A is a graph showing primary bitumen recovery (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AAX.
FIG. 6B is a graph showing the combined bitumen recovery (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AAX.
FIG. 7A is a graph showing primary froth bitumen content (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AAX.
FIG. 7B is a graph showing primary froth water content (%) as a function of dosage (%) using caustic alone or in combination with sodium silicate for poor oil sand AAX.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
The present invention relates generally to a process of extracting bitumen from mined oil sand ores by adding a combination of sodium silicate and caustic to condition the oil sand slurry.
In one embodiment of the process of the present invention useful in extracting bitumen from oil sand ores, oil sand is mined from an oil sand rich area such as the Athabasca Region of Alberta. The oil sand ore may comprise a fines content up to about 60 wt%
and a bitumen content greater than about 6 wt%.
FIG. 1 is a general schematic of a water-based process for extracting bitumen from mined oil sand ore. The mined oil sand, which may be pre-crushed, is mixed with heated water in a slurry preparation unit. The slurry preparation unit may comprise a tumbler, screening device and pump box, a wet crusher, etc.; however, it is understood that any slurry preparation unit known in the art can be used.
In addition to the oil sand and water, sodium silicate and caustic are also added to aid in conditioning the oil sand slurry. In one embodiments, the caustic and sodium silicate are added to the heated water prior to slurry preparation. In another embodiment, the sodium silicate and caustic are added to the slurry preparation unit. In another embodiment, the sodium silicate and caustic are added after slurry preparation but prior to slurry conditioning. When using a tumbler, slurry conditioning can occur in the tumbler itself. In another embodiment, the oil sand slurry may be screened through a screen portion, where additional water may be added to clean the rejects (e.g., oversized rocks) prior to delivering the rejects to a rejects pile. The screened oil sand slurry is collected in a vessel such as pump box where the oil sand slurry is then pumped through a hydrotransport pipeline, which is at least 2 km in length, where slurry conditioning occurs. As used herein "slurry conditioning" generally means that the larger lumps of oil sand are ablated or digested and the released bitumen flecks coalesce and attach to air bubbles.
'CA 3060461 2019-10-28 6 Following slurry preparation and slurry conditioning, the slurry is transported to a gravity separator such as a primary separation vessel (PSV) where bitumen separation occurs.
In particular, the bitumen froth rises to the top of the PSV and the coarse tailings settle at the bottom of the PSV. The bitumen froth obtained from the PSV is referred to herein as primary froth. Additional bitumen can be obtained from the middlings layer which forms between the froth layer and the coarse tailings using additional froth flotation.
This bitumen froth is referred to herein as secondary froth.
It is understood that there are different forms of sodium silicate, which are characterized by the ratio of Si02:Na20. In general, for the purposes of the present invention, only sodium silicate with a low Si02:Na20 ratio in the range of 0.5 to 3.22 should be used. In the following examples, sodium silicate with a Si02:Na20 ratio of 1:1 was used.
Exemplary embodiments of the present invention are described in the following Examples, which are set forth to aid in the understanding of the invention, and should not be construed to limit in any way the scope of the invention as defined in the claims which follow thereafter.
In the following Examples, a Batch Extraction Unit was used to test sodium silicate as a secondary process aid in combination with caustic using a variety of different oil sand ores. The BEU is a low-shear laboratory approximation of the Clark Hot Water Extraction Process. It typically produces a froth similar to that obtained from the traditional commercial process with conditioning and separation stages. Froth is produced in two stages with the BEU: a "primary froth" and a "secondary froth." A
detailed description of the steps and variables involved in the BEU extraction can be found at Sanford, E.C. and F.A. Seyer, "Processibility of Athabasca Tar Sand Using a Batch Extraction Unit: The Role of NaOH", Can. Inst. Min. Metal!. Bull., 72(803), 164-169 (1979).

. .
Example '1 In this example, a poor processing ore was used. In particular, the oil sand ore was a marine ore having a bitumen content of 9.0 wt% and a fines content of 26 wt%
Various chemical doses of caustic alone (0-0.05 %), sodium silicate alone (0-0.05%) and combinations of caustic and sodium silicate were tested using the BEU.
Table 1 below outlines the results obtained in terms of Bitumen Recovery, ')/0 (Primary and Combined (Primary and Secondary)) and Primary Froth Bitumen Content, %.
Table 1 Chemical Dose, % Bitumen Recovery, % Primary Froth Memo Total NaOH Silicate Primary Combined Bitumen Content, %
0 0 0 11.6 21.9 21.7 Caustic 0.01 0.01 0 13.81 28.81 24.8 Only 0.02 0.02 0 15.5 30.3 25.9 0.03 0.03 0 21.1 38.8 28.8 0.04 0.04 0 17.9 35.00 29.4 0.05 0.05 0 32.2 50.8 31.1 0.01 0 0.01 15.7 28.9 25.9 Silicate 0.02 0 0.02 17.0 32.8 29.9 Only 0.03 0 0.03 16.7 33.7 26.1 0.05 0 0.05 13.3 25.7 21.1 0.04 0.03 0.01 30.1 51.9 37.4 Combined 0.05 0.03 0.02 34.6 59.0 38.9 Combined 0.06 0.03 0.03 36.5 63.1 41,4 Combined \CA 3060461 2019-10-28 8 One aspect of the present invention is to discover combinations of caustic and sodium silicate that have less than 0.05% caustic but are as effective or more effective than 0.05% caustic. The industry standard is to try to not exceed a caustic dosage of greater than 0.05% due to the problems encountered, as discussed above.
As can be seen in Table 1, using sodium silicate as a second process aid with reduced amount of caustic not only resulted in comparable bitumen recovery but in some instances exceeded expectations. In particular, when using a dosage of 0.05%
caustic (the maximum desired caustic), the combined bitumen recovery was 50.8%
(compared to 21.9% with no additive); however, when the combination of 0.03% caustic and 0.02%
sodium silicate was used (i.e., the same overall chemical dose as with caustic alone), the combined bitumen recovery was 59.0 %, an increased recovery of around 16%.
Similarly, there was a significant increase in the amount of bitumen in primary froth, i.e., 31.1% versus 38.9%, resulting in a 25% increase in bitumen content. Thus, there is a 40% reduction in caustic use, a 0% change in overall chemical dosage, and a 25%
.. increase in primary froth bitumen content.
Table 1 also shows that when using 0.03% caustic and 0.01% sodium silicate (a 20%
reduction in overall chemical dosage) the percent combined bitumen was slight higher than with 0.05% caustic and the bitumen content in primary froth was increased by 20%. Furthermore, 0.04% of caustic alone only resulted in 29.4% bitumen content in primary froth and 0.05% of sodium silicate only resulted in 21.1% bitumen in primary froth. The results of this experiment clearly demonstrated a strong synergy between caustic and sodium silicate, which can be seen even more clearly in Example 2.
Example 2 A Batch Extraction Unit (BEU) was used to test sodium silicate as a secondary process .. aid in combination with caustic for the processing of three different oil sands of poor quality (i.e., poor processing ores). Table 2 summarizes the information of the three poor oil sands tested. Oil sand ore AR was a low-grade ore with an average fines content of ¨26% <44pm. Oil sand ores AAX and AD were of low grade and had very µCA 3060461 2019-10-28 9 high fines content. Oil sand ores AAX and AR were marine whereas oil sand ore AD
was an estuarine ore. All three oil sand ores are considered to be poor processing ores with low bitumen recovery when no chemical was used. Table 2 summarized the characteristics of the three ores tested.
Table 2: Summary of Oil Sands Tested Designation AR AAX AD
Ore Type Marine Marine Estuarine Grade (% bitumen) 9.0 8.7 9.6 Fines content, % 26 39 38 Table 3 below provides a summary of the BEU test results. When no chemical was used (total dosage at 0), all three oil sand ores had relatively low recoveries, indicating they were all poor processing ores. The primary bitumen recoveries were only about 12% and 13%, respectively, for oil sand ores AR and AAX and their primary froth was of extremely poor quality (low bitumen and high water content). Oil sand ore AD
had a primary recovery at about 70%.

. .
Table 3 Oil Chemical Dosage, %
Bitumen Recovery, Primary Froth Quality (%) Sand %
Silicate Caustic Total Primary Combined Bitumen Water Solids AR 0 11.6 21.9 21.7 71.4 6.9 AR 0.03 0.03 21.1 38.8 28.8 62.2 9.0 AR 0.04 0.04 17.9 35.0 29.4 61.2 9.4 AR 0.05 0.05 32.2 50.8 31.1 58.5 10.4 AR 0.01 0.03 0.04 30.1 51.9 37.4 52.3 10.3 AR 0.02 0.03 0.05 34.6 59.0 38.9 51.8 9.3 AR 0.03 0.03 0.06 36.5 63.1 41.4 46.1 12.5 AD 0 70.2 86.1 50.3 41.5 8.2 AD 0.02 0.02 70.5 88.5 48.2 42.5 9.3 AD 0.03 0.03 73.1 89.1 48.1 42.0 9.9 AD 0.04 0.04 78.9 90.8 48.7 40.7 10.6 AD 0.05 0.05 78.6 90.7 48.6 41.7 9.7 AD 0.01 0.02 0.03 82.7 91.0 52.6 38.9 8.5 AD 0.02 0.02 0.04 85.5 91.2 61.1 29.6 9.3 AD 0.03 0.02 0.05 87.9 91.6 64.1 26.5 9.4 AAX 0 13.0 21.6 19.7 72.5 7.8 AAX 0.03 0.03 21.5 34.1 28.0 64.0 8.0 AAX 0.04 0.04 22.9 38.3 29.4 62.8 7.8 AAX 0.05 0.05 26.7 42.9 34.8 58.2 7.0 AAX 0.01 0.03 0.04 30.7 45.3 34.5 58.5 7.0 AAX 0.02 0.03 0.05 48.7 63.8 42.3 49.3 8.4 AAX 0.03 0.03 0.06 54.1 70.3 45.2 44.9 9.9 FIGS. 2A and 2B show the results of the primary bitumen recovery (%) and the combined bitumen recovery (%), respectively, as a function of the total chemical dosage for oil sand ore AR. It can be seen in FIGS. 2A and 2B that the combined use of sodium silicate with caustic had a higher bitumen recovery (both primary and combined) than the use of caustic alone at the same total dosage. The absolute recovery uplift could be greater than 10%. Both primary and combined bitumen recoveries show a continuously increasing trend with the use of more sodium silicate.
FIGS. 3A and 3B show the primary froth bitumen content and water content, respectively, which are representative of the primary froth quality, as a function of the total chemical dosage for oil sand ore AR. As previously mentioned, it is desirable for primary bitumen froth to have a low water content and high bitumen content.
Primary bitumen froth from good processing oil sand ores generally has about 60%
bitumen, 30% water and 10% solids.
It can be seen that the combined use of sodium silicate with caustic was able to significantly improve froth quality, with both increased bitumen content (FIG.
3A) and decreased water content (FIG. 3B). In general, FIGS. 2A and 2B and FIGS. 3A
and 3B
show that the use of silicate as a secondary process aid in addition to caustic significantly improved both bitumen recovery and bitumen froth quality, as compared to the use of caustic alone for oil sand ore AR. This indicates that a strong synergy exists between caustic and sodium silicate in improving the processability of oil sand ore AR.
FIGS. 4A and 4B show the results of the primary bitumen recovery (%) and the combined bitumen recovery (%), respectively, as a function of the total chemical dosage for oil sand ore AD. For this ore, even though the use of caustic alone led to primary bitumen recoveries of >70%, the combined use of silicate with caustic still resulted in both higher primary bitumen recovery and combined bitumen recovery when the same total dosages were used. The absolute uplifts were up to about 10% for primary bitumen recovery.
FIGS. 5A and 5B show the primary froth bitumen content and water content, respectively, which are representative of the primary froth quality, as a function of the total chemical dosage for oil sand ore AD. With the use of caustic alone, the primary froth quality had little change with increased caustic dosage. For the combined use of caustic (at the constant dosage of 0.02%) and sodium silicate, the froth quality kept \CA 3060461 2019-10-28 12 ' improving with increased sodium silicate dosage. At the total chemical dosage of 0.05%, the primary froth bitumen content was increased from about 49% with the use of caustic alone to about 64% with the combined use. Further, the primary froth water content was reduced from about 42% to about 27%, accordingly. In general, FIGS. 4A
and 4B and FIGS. 5A and 5B show that the combined use of sodium silicate with caustic was not only able to improve bitumen recovery but also capable of greatly improving froth quality for oil sand ore AD.
FIGS. 6A and 6B show the results of the primary bitumen recovery (%) and the combined bitumen recovery (%), respectively, as a function of the total chemical dosage for oil sand ore AAX. For this ore, the use of caustic alone was able to increase bitumen recovery but the improvement was limited. With the combined use of sodium silicate with caustic, dramatic improvements in recovery can be seen clearly in FIGS. 6A
and 6B. At the total chemical dosage of 0.05%, the primary bitumen recovery was increased from about 23% with the use caustic alone to about 49% with the combined use of both chemicals, and the absolute uplift in primary recovery was as high as about 26%. The absolute uplift in combined recovery was also very high at about 22%.
These numbers show that the combined use of sodium silicate with caustic significantly improved the processability of this poor processing ore (AAX).
FIGS. 7A and 7B show the primary froth bitumen content and water content, respectively, which are representative of the primary froth quality, as a function of the total chemical dosage for oil sand ore AAX. For this ore, FIGS. 7A and 7B show that the use of caustic alone was able to improve froth quality (increasing bitumen content and reducing water content) with increased caustic usage. Even so, the combined use of sodium silicate with caustic was able to achieve a much higher improvement than the use of caustic alone.
In summary, for all three ores tested, the combined use of sodium silicate with caustic was able to significantly improve both bitumen recovery and primary froth quality and performed much better than the use of caustic alone. It was shown that a strong synergy existed between sodium silicate and caustic in improving ore processability.
VcA 3060461 2019-10-28 13 As previously mentioned, the combined use of sodium silicate and caustic is preferred due to the lowering of the amount of caustic used. For each of the poor ores (AR, AD
and AAX), the overall performance (both recovery and froth quality) was improved by the combination of reagents compared to use of caustic alone. In general, the combined use of sodium silicate and caustic required a lower amount of total chemical addition than the use of caustic alone, and was more effective at much lower dosages than the use of caustic alone.
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.
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.
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.

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.
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.
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.
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.
\CA 3060461 2019-10-28 15

Claims (11)

WHAT IS CLAIMED:

1. A water-based process of extracting bitumen from oil sand ore, comprising:
(a) determining a dosage (wt%) of caustic necessary to maximize bitumen recovery for the oil sand ore to be processed when using caustic alone as a process aid;
(b) determining an amount of caustic (wt%) and an amount of sodium silicate (wt%) which yields substantially the same bitumen recovery or greater than when using caustic alone;
(c) mixing the oil sand ore with heated water to produce an oil sand slurry;
and (d) adding the amounts of caustic (wt%) and sodium silicate (wt%) before, during or after mixing the oil sand ore with heated water to condition the oil sand slurry and to improve bitumen recovery from the oil sand ore;
wherein the sum of the amounts of caustic (wt%) and sodium silicate (wt%) is substantially equal to or less than the dosage (wt%) of caustic alone.

2. The process as claimed in claim 1, wherein the dosage of caustic ranges from about 0.01 to less than 0.05 wt% of the oil sand ore and the sodium silicate dosage ranges from about 0.003 to about 0.05 wt% of the oil sand ore.

3. The process as claimed in claim 1, wherein the dosage of caustic ranges from about 0.01 to about 0.03 wt% of the oil sand ore and the sodium silicate dosage ranges from about 0.003 to about 0.03 wt% of the oil sand ore.

4. The process as claimed in claim 1, wherein the caustic is sodium hydroxide.

5. The process as claimed in any one of claims 1 to 4, wherein the oil sand ore is a poor processing ore having low bitumen content of about 6 to about 10 wt% or a high fines content greater than about 25 wt% or both.

6. The process as claimed in claim 3, wherein the bitumen content of the oil sand ore ranges from about 6 wt% to about 10 wt% and the fines content of the oil sand ore is greater than about 25 wt%.

7. The process as claimed in claim 1, wherein the sum of the amounts of caustic (wt%) and sodium silicate (wt%) is about 0.05 wt% or less of the oil sand ore.

8. The process as claimed in claim 1, wherein the bitumen content is about wt%, the fines content is about 26 wt%, the caustic amount is about 0.03 wt%, and the sodium silicate amount ranges from about 0.003 wt% to about 0.03 wt%.

9. The process as claimed in claim 1, wherein the bitumen content is about 8.7 wt%, the fines content is about 39%, the caustic amount is about 0.03 wt%, and the sodium silicate amount ranges from about 0.003 wt% to about 0.03 wt%.

10. The process as claimed in claim 1, wherein the bitumen content is about 9.6 wt%, the fines content is about 38 wt%, the caustic amount is about 0.02 wt%, and the sodium silicate amount ranges from about 0.003 wt% to about 0.03 wt%.

11. The process as claimed in claim 1, wherein the sodium silicate has a Si02:Na20 ratio in the range of 0.5 to 3.22.