Note: Descriptions are shown in the official language in which they were submitted.
CA 02899348 2015-08-04
PROCESSING OIL SAND STREAMS
BACKGROUND
Field of Disclosure
[0001] The disclosure relates generally to the field of oil sand
processing.
Description of Related Art
[0002] This section is intended to introduce various aspects of the art,
which may be
associated with the present disclosure. This discussion is believed to assist
in providing a
framework to facilitate a better understanding of particular aspects of the
present disclosure.
Accordingly, it should be understood that this section should be read in this
light, and not
necessarily as admissions of prior art.
[0003] Modern society is greatly dependent on the use of hydrocarbon
resources for
fuels and chemical feedstocks. Hydrocarbons are generally found in subsurface
formations
that can be termed "reservoirs". Removing hydrocarbons from the reservoirs
depends on
numerous physical properties of the subsurface formations, such as the
permeability of the
rock containing the hydrocarbons, the ability of the hydrocarbons to flow
through the
subsurface formations, and the proportion of hydrocarbons present, among other
things.
Easily harvested sources of hydrocarbons are dwindling, leaving less
accessible sources to
satisfy future energy needs. As the costs of hydrocarbons increase, the less
accessible sources
become more economically attractive.
[0004] Recently, the harvesting of oil sand to remove heavy oil has
become more
economical. Hydrocarbon removal from oil sand may be performed by several
techniques.
For example, a well can be drilled to an oil sand reservoir and steam, hot
air, solvents, or a
combination thereof, can be injected to release the hydrocarbons. The released
hydrocarbons
may be collected by wells and brought to the surface. In another technique,
strip or surface
mining may be performed to access the oil sand, which can be treated with
water, steam or
solvents to extract the heavy oil.
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[0005] Oil sand extraction processes are used to liberate and separate
bitumen from oil
sand so that the bitumen can be further processed to produce synthetic crude
oil or mixed with
diluent to form "dilbit" and be transported to a refinery plant. Numerous oil
sand extraction
processes have been developed and commercialized, many of which involve the
use of water
as a processing medium. Where the oil sand is treated with water, the
technique may be
referred to as water-based extraction (WBE). WBE is a commonly used process to
extract
bitumen from mined oil sand. Other processes are non-aqueous solvent-based
processes. An
example of a solvent-based process is described in Canadian Patent Application
No.
2,724,806 (Adeyinka et al, published June 30, 2011 and entitled "Process and
Systems for
Solvent Extraction of Bitumen from Oil Sands"). Solvent may be used in both
aqueous and
non-aqueous processes.
[0006] One WBE process is the Clark hot water extraction process (the
"Clark
Process"). This process typically requires that mined oil sand be conditioned
for extraction by
being crushed to a desired lump size and then combined with hot water and
perhaps other
agents to form a conditioned slurry of water and crushed oil sand. In the
Clark Process, an
amount of sodium hydroxide (caustic) may be added to the slurry to increase
the slurry pH,
which enhances the liberation and separation of bitumen from the oil sand.
Other WBE
processes may use other temperatures and may include other conditioning
agents, which are
added to the oil sand slurry, or may operate without conditioning agents. This
slurry is first
processed in a Primary Separation Cell (PSC), also known as a Primary
Separation Vessel
(PSV), to extract the bitumen from the slurry.
[0007] In one bitumen extraction process, a water and oil sand slurry is
separated into
three major streams in the PSC: bitumen froth, middlings, and a PSC underflow.
[0008] Regardless of the type of WBE process employed, the process will
typically
result in the production of a bitumen froth that requires treatment with a
solvent. For example,
in the Clark Process, a bitumen froth stream comprises bitumen, solids, and
water. Certain
processes use naphtha to dilute bitumen froth before separating the product
bitumen by
centrifugation. These processes are called naphtha froth treatment (NFT)
processes. Other
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411b
processes use a paraffinic solvent, and are called paraffinic froth treatment
(PFT) processes, to
produce pipelineable bitumen with low levels of solids and water. In the PFT
process, a
paraffinic solvent (for example, a mixture of iso-pentane and n-pentane) is
used to dilute the
froth before separating the product, diluted bitumen, by gravity. A portion of
the asphaltenes
in the bitumen is also rejected by design in the PFT process and this
rejection is used to
achieve reduced solids and water levels. In both the NFT and the PFT
processes, the diluted
tailings (comprising water, solids and some hydrocarbon) are separated from
the diluted
product bitumen.
100091 Solvent is typically recovered from the diluted product bitumen
component
before the bitumen is delivered to a refining facility for further processing.
[0010] The PFT process may comprise at least three units: Froth
Separation Unit
(FSU), Solvent Recovery Unit (SRU) and Tailings Solvent Recovery Unit (TSRU).
Mixing of
the solvent with the feed bitumen froth may be carried out counter-currently
in two stages in
separate froth separation units. The bitumen froth comprises bitumen, water,
and solids. A
typical composition of bitumen froth is about 60 wt. % bitumen, 30 wt. %
water, and 10 wt. %
solids. The paraffinic solvent is used to dilute the froth before separating
the product bitumen
by gravity. The foregoing is only an example of a PFT process and the values
are provided by
way of example only. An example of a PFT process is described in Canadian
Patent No.
2,587,166 to Sury.
[0011] From the PSC, the middlings, comprising bitumen and about 10-30
wt. %
solids, or about 20-25 wt. % solids, based on the total wt. % of the
middlings, is withdrawn
and sent to the flotation cells to further recover bitumen. The middlings are
processed by
bubbling air through the slurry and creating a bitumen froth, which is
recycled back to the
PSC. Flotation tailings (FT) from the flotation cells, comprising mostly
solids and water, are
sent for further treatment or disposed in an external tailings area (ETA).
[00121 In ETA tailings ponds, a liquid suspension of oil sand fines in
water with a
solids content greater than 2 wt. %, but less than the solids content
corresponding to the
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Liquid Limit are called Fluid Fine Tailings (FFT). FFT settle over time to
produce Mature
Fine Tailings (MFT), having above about 30 wt. % solids.
[0013] It would be desirable to have an alternative or improved method of
controlling
an oil sand treatment process.
SUMMARY
[0014] It is an object of the present disclosure to provide a method of
controlling an
oil sand treatment process.
[0015] Disclosed is a method of controlling an oil sand treatment
process. The
method comprises analyzing an oil sand stream of the oil sand treatment
process to obtain a
ratio of aluminum to silicon in the oil sand stream, and adjusting a parameter
of the oil sand
treatment process based on the ratio.
[0016] The foregoing has broadly outlined the features of the present
disclosure so
that the detailed description that follows may be better understood.
Additional features will
also be described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] These and other features, aspects and advantages of the disclosure
will become
apparent from the following description, appending claims and the accompanying
drawings,
which are briefly described below.
[0018] Fig. 1 is a flow chart of a method of controlling an oil sand
treatment process.
[0019] Fig. 2 is a graph of clay fraction of mineral solids as a function
of Al:Si wt. %,
from an oil sand ore sample.
[0020] Fig. 3 is a graph of clay fraction of mineral solids as a function
of K wt. %,
from an oil sand ore sample.
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[0021] Fig. 4 is a graph of clay fraction of mineral solids as a function
of Al:Si wt. %,
from an oil sand tailings sample.
[0022] Fig. 5 is a graph of clay fraction of mineral solids as a function
of K wt. %,
from an oil sand tailings sample.
[0023] It should be noted that the figures are merely examples and no
limitations on
the scope of the present disclosure are intended thereby. Further, the figures
are generally not
drawn to scale, but are drafted for purposes of convenience and clarity in
illustrating various
aspects of the disclosure.
DETAILED DESCRIPTION
[0024] For the purpose of promoting an understanding of the principles of
the
disclosure, reference will now be made to the features illustrated in the
drawings and specific
language will be used to describe the same. It will nevertheless be understood
that no
limitation of the scope of the disclosure is thereby intended. Any alterations
and further
modifications, and any further applications of the principles of the
disclosure as described
herein are contemplated as would normally occur to one skilled in the art to
which the
disclosure relates. It will be apparent to those skilled in the relevant art
that some features that
are not relevant to the present disclosure may not be shown in the drawings
for the sake of
clarity.
[0025] At the outset, for ease of reference, certain terms used in this
application and
their meaning as used in this context are set forth below. To the extent a
term used herein is
not defined below, it should be given the broadest definition persons in the
pertinent art have
given that term as reflected in at least one printed publication or issued
patent. Further, the
present processes are not limited by the usage of the terms shown below, as
all equivalents,
synonyms, new developments and terms or processes that serve the same or a
similar purpose
are considered to be within the scope of the present disclosure.
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[0026] Throughout this disclosure, where a range is used, any number
between or
inclusive of the range is implied.
[0027] A "hydrocarbon" is an organic compound that primarily includes the
elements
of hydrogen and carbon, although nitrogen, sulfur, oxygen, metals, or any
number of other
elements may be present in small amounts. Hydrocarbons generally refer to
components
found in heavy oil or in oil sand. However, the techniques described are not
limited to heavy
oils but may also be used with any number of other reservoirs to improve
gravity drainage of
liquids. Hydrocarbon compounds may be aliphatic or aromatic, and may be
straight chained,
branched, or partially or fully cyclic.
[0028] "Bitumen" is a naturally occurring heavy oil material. Generally,
it is the
hydrocarbon component found in oil sand. Bitumen can vary in composition
depending upon
the degree of loss of more volatile components. It can vary from a very
viscous, tar-like,
semi-solid material to solid forms. The hydrocarbon types found in bitumen can
include
aliphatics, aromatics, resins, and asphaltenes. A typical bitumen might be
composed of:
19 weight (wt.) % aliphatics (which can range from 5 wt. % - 30 wt. %, or
higher);
19 wt. % asphaltenes (which can range from 5 wt. % - 30 wt. %, or higher);
30 wt. % aromatics (which can range from 15 wt. % - 50 wt. %, or higher);
32 wt. % resins (which can range from 15 wt. % - 50 wt. %, or higher); and
some amount of sulfur (which can range in excess of 7 wt. %), the weight %
based
upon total weight of the bitumen.
In addition, bitumen can contain some water and nitrogen compounds ranging
from less than
0.4 wt. % to in excess of 0.7 wt. %. The percentage of the hydrocarbon found
in bitumen can
vary. The term "heavy oil" includes bitumen as well as lighter materials that
may be found in
a sand or carbonate reservoir.
[0029] "Heavy oil" includes oils which are classified by the American
Petroleum
Institute ("API"), as heavy oils, extra heavy oils, or bitumens. The term
"heavy oil" includes
bitumen. Heavy oil may have a viscosity of about 1,000 centipoise (cP) or
more, 10,000 cP or
more, 100,000 cP or more, or 1,000,000 cP or more. In general, a heavy oil has
an API gravity
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between 22.3 API (density of 920 kilograms per meter cubed (kg/m3) or 0.920
grams per
centimeter cubed (g/cm3)) and 10.0 API (density of 1,000 kg/m3 or 1 g/cm3).
An extra heavy
oil, in general, has an API gravity of less than 10.00 API (density greater
than 1,000 kg/m3 or
1 g/cm3). For example, a source of heavy oil includes oil sand or bituminous
sand, which is a
combination of clay, sand, water and bitumen. The recovery of heavy oils is
based on the
viscosity decrease of fluids with increasing temperature or solvent
concentration. Once the
viscosity is reduced, the mobilization of fluid by steam, hot water flooding,
or gravity is
possible. The reduced viscosity makes the drainage or dissolution quicker and
therefore
directly contributes to the recovery rate.
[0030] The term "bituminous feed" refers to a stream derived from oil
sand that
requires downstream processing in order to realize valuable bitumen products
or fractions.
The bituminous feed is one that comprises bitumen along with undesirable
components.
Undesirable components may include but are not limited to clay, minerals,
coal, debris and
water. The bituminous feed may be derived directly from oil sand, and may be,
for example,
raw oil sand ore. Further, the bituminous feed may be a feed that has already
realized some
initial processing but nevertheless requires further processing. Also,
recycled streams that
comprise bitumen in combination with other components for removal as described
herein can
be included in the bituminous feed. A bituminous feed need not be derived
directly from oil
sand, but may arise from other processes. For example, a waste product from
other extraction
processes which comprises bitumen that would otherwise not have been recovered
may be
used as a bituminous feed.
[0031] "Fine particles" or "fines" are generally defined as those solids
having a size
of less than 44 microns (um), as determined by laser diffraction particle size
measurement.
[0032] "Coarse particles" are generally defined as those solids having a
size of greater
than 44 microns (um).
[0033] The term "solvent" as used in the present disclosure should be
understood to
mean either a single solvent, or a combination of solvents.
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[0034] The terms "approximately," "about," "substantially," and similar
terms are
intended to have a broad meaning in harmony with the common and accepted usage
by those
of ordinary skill in the art to which the subject matter of this disclosure
pertains. It should be
understood by those of skill in the art who review this disclosure that these
terms are intended
to allow a description of certain features described and claimed without
restricting the scope
of these features to the precise numeral ranges provided. Accordingly, these
terms should be
interpreted as indicating that insubstantial or inconsequential modifications
or alterations of
the subject matter described and are considered to be within the scope of the
disclosure.
[0035] The articles "the", "a" and "an" are not necessarily limited to
mean only one,
but rather are inclusive and open ended so as to include, optionally, multiple
such elements.
[0036] The term "paraffinic solvent" (also known as aliphatic) as used
herein means
solvents comprising normal paraffins, isoparaffins or blends thereof in
amounts greater than
50 wt. %. Presence of other components such as olefins, aromatics or
naphthenes may
counteract the function of the paraffinic solvent and hence may be present in
an amount of
only 1 to 20 wt. % combined, for instance no more than 3 wt. %. The paraffinic
solvent may
be a C4 to C20 or C4 to C6 paraffinic hydrocarbon solvent or a combination of
iso and normal
components thereof. The paraffinic solvent may comprise pentane, iso-pentane,
or a
combination thereof. The paraffinic solvent may comprise about 60 wt. %
pentane and about
40 wt. % iso-pentane, with none or less than 20 wt. % of the counteracting
components
referred above.
[0037] The inventors have shown that a ratio of aluminum (Al) to silicon
(Si) in an oil
sand stream can be valuable information and can be used to adjust oil sand
treatment
processes.
[0038] The present disclosure provides a method of controlling an oil
sand treatment
process. With reference to Figure 1, first, an oil sand stream of the oil sand
treatment process
is analyzed (102) to obtain a ratio of aluminum to silicon in the oil sand
stream. Then, a
parameter of the oil sand treatment process is adjusted (104) based on the
ratio.
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[0039] The ratio may be an elemental signal ratio, a molar ratio, or
weight ratio.
[0040] The analysis may be achieved by any suitable technique capable of
determining or otherwise approximating the ratio.
For instance, the analysis may be of
visible light, x-rays, or gamma rays. The analysis may use LIBS (Laser-Induced
Breakdown
Spectroscopy), XRF (X-Ray Fluorescence), PGNAA (Prompt Gamma Neutron
Activation
Analysis), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES),
or
Atomic Absorption (AA).
[0041] The analysis may be effected online, inline, offline, or atline.
[0042] The "oil sand stream" is any suitable stream stemming from oil
sand.
Examples include, but are not limited to, oil sand, a bituminous feed, a
bitumen froth, tailings,
a stream from an aqueous based extraction, a stream from solvent based
extraction, a solvent
diluted bitumen froth, a hydrotransport slurry, a solvent-ore slurry, or a
combination thereof.
The tailings may be primary separation tailings, middlings, flotation
tailings, froth separation
tailings, tailings solvent recovery unit (TSRU) tailings, fluid fine tailings
(FFT), mature fine
tailings (MFT), thickened tailings, centrifuged tailings, hydrocycloned
tailings, or a
combination thereof.
[0043] More particularly, the oil sand stream may comprise a bituminous
feed, a
bitumen froth, or a tailings stream. The oil sand stream may stem from aqueous
based
extraction. The oil sand stream may stem from solvent based extraction. The
oil sand stream
may comprise solvent diluted bitumen froth. The oil sand stream may comprise
primary
separation tailings, middlings, flotation tailings, froth separation tailings,
tailings solvent
recovery unit (TSRU) tailings, fluid fine tailings (FFT), mature fine tailings
(MFT), thickened
tailings, centrifuged tailings, hydrocycloned tailings, or a combination
thereof. The oil sand
stream may comprise oil sand ore, a hydrotransport slurry, or a solvent-ore
slurry.
[0044] The "oil sand treatment process" simply means a process used to
treat an oil
sand stream. Examples of treatment are vast. To name only three, we can name
reducing a
solids content, removing water, and removing solvent. The oil sand treatment
process may
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comprise ore feed blending, primary bitumen conditioning and separation,
bitumen froth
treatment, or bitumen tailings treatment.
[0045] While the Al:Si ratio may be used to adjust the process, the ratio
may also be
converted to another measurement, which can provide useful information and
which can in
turn be used to adjust a process parameter.
[0046] For instance, a clay fraction of mineral solids in the oil sand
stream may be
approximated using the ratio and reference data. The clay fraction is the clay
content as a
fraction of total mineral solids, and may be on a weight basis. The clay
fraction may be used
to adjust a process parameter.
[0047] The method is technology-agnostic with respect to the instrument
used to
generate the data, provided that a Al:Si ratio can be measured. The
measurement need not be
accurate in terms of the Al:Si ratio itself, it may merely provide a useful
correlation to the
clay fraction or other parameter. The selected instrument need not directly
report the weight
or elemental percentages of Al and Si. If the instrument is known to produce
linear signal
response with changes in Al and Si weight for instance, then the ratio of
Al:Si signal is
sufficient without performing an intermediary determination of the weight or
elemental
fraction of each component. The measurement may then be used to adjust a
process
parameter.
[0048] In oil sand ore, multiple types of clay are present, such as
kaolinite, illite,
chlorite, mica, and smectite. The Al and Si content of these clays can vary
substantially
among clay types. Al can vary between about 10-22 wt. %, based upon the total
weight of the
clay. Si can vary between about 15-31wt. %, based upon the total weight of the
clay.
Additionally, ore may comprise other minerals that comprise Al and/or Si, such
as albite and
microcline. These facts suggest that Al:Si ratio alone may be an inaccurate
indicator of clay
content. However, as Fig. 2 illustrates, concentrations of minerals are not
random, such that
the Al:Si ratio can be used to approximate a clay fraction of mineral solids
with a reasonable
or useful degree of consistency and/or accuracy. Fig. 2 is a plot of clay
fraction of mineral
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solids as measured by X-Ray Diffraction (XRD) against an estimate of Al:Si wt.
% ratio of
mineral solids. The Al:Si wt. % ratio is estimated by assigning elemental
compositions to
XRD profiles. The samples used were oil sand ore samples. The samples excluded
any
samples having less than 40 wt. % quartz or more than 50 wt. % clay, as these
fall outside the
range of ores that are typically processed in significant quantities. Water,
bitumen, and
hydrocarbon solvent comprise negligible amounts of Si and Al such that this
approach may be
used with a wide variety of oil sand streams without regard to these non-
mineral components.
[0049] A particle size in the oil sand stream may be approximated using
the clay
fraction and reference data. The particle size parameter may be a fraction of
particles falling
within a predetermined size range. The predetermined size range may be 0-44
microns,
namely fines. The particle size parameter may be used to adjust a process
parameter.
[0050] Clay and sand (quartz) are typically the primary mineral
components in
typical oil sand streams. Si is the primary metal in quartz, while both Si and
Al are present in
clays. Combined with density measurements, this ratio can provide the absolute
clay content
of a stream. Therefore, a total clay content in the oil sand stream may be
approximated using
the ratio and a solids mass measurement of the oil sand stream. The total clay
content may be
used to adjust a process parameter.
[0051] A methylene blue index (MBI) value in the oil sand stream may be
approximated using the clay fraction and reference data. The MBI may be used
to adjust a
process parameter.
[0052] The reference data discussed herein may be experimental data or
otherwise.
[0053] To date, the oil sand industry has struggled with analyzing clay
content of oil
sand streams. A measurement of total clay may be used for process control.
Analysis work
has shown that correlations exist between total clay content, methylene blue
index (MBI), and
sands to fines ratio (SFR) of flotation tailings samples. For operation of a
thickener, blending
of feed streams may be performed to achieve a target feed SFR window, and
chemical dosage
is informed by the MBI of the combined streams. Therefore, measurement of
total clay could
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be used for feed-forward control of both of these applications. Similar
examples may be
found in other oil sand processing, such as polymer dosage control.
[0054] One existing method for online clay measurement is the K40
Analyzer,
available from Industrial Sensors Technologies (Edmonton, Canada). The K40
Analyzer
measures gamma ray emissions from radioactive decay of potassium (K). However,
K is only
present in some oil sand clay (such as illite and mica) and is also present in
other minerals
(such as microcline). Therefore, the use of K as a clay signature may be less
robust than the
Al:Si ratio, as illustrated by comparing Fig. 3 (using K) to Fig. 2 (using
Al:Si). Fig. 3 is a plot
of clay fraction of mineral solids as measured by X-Ray Diffraction (XRD)
against an
estimate of K wt. % of the minerals. The K wt. % is estimated by assigning
elemental
compositions to XRD profiles. As with Fig. 2, the samples used were oil sand
ore samples. As
with Fig. 2, the samples excluded any samples having less than 40 wt. % quartz
or more than
50 wt. % clay.
[0055] Figures 4 and 5 are similar to Figures 2 and 3 except that the
samples were oil
sand tailings samples rather than oil sand ore samples. As with Fig. 2, Fig. 4
illustrates that
concentrations of minerals are not random, such that the Al:Si ratio can be
used to
approximate a clay fraction of mineral solids with a reasonable or useful
degree of
consistency and/or accuracy. The use of K as a clay signature may be less
robust than the
Al:Si ratio, as illustrated by comparing Fig. 5 (using K) to Fig. 4 (using
Al:Si).
[0056] While Figures 2 to 5 are provided to illustrate the existence and
strength of the
correlation, the particular values of Figures 2 to 5 are specific to a
particular ore and oil sand
process, and are therefore not included. To use the invention, a data set
should be created that
is particular to an oil sand stream being processed.
[0057] By way of example only, where the oil sand stream is a bituminous
feed, the
ratio of aluminum to silicon in the bituminous feed may be between 0 and 0.33
and/or the clay
fraction of mineral solids in the bituminous feed may be between 0 and 0.5.
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[0058] By way of example only, where the oil sand stream is a tailings
stream, the
ratio of aluminum to silicon in the tailings stream may be between 0 and 0.65,
and/or the clay
fraction of mineral solids in the tailings stream may be between 0 and 1.
[0059] The process adjustment may be any suitable process adjustment.
Various non
limiting examples are provided below, separated by category.
[0060] In the category of ore and slurry preparation, the following are
mentioned:
blending of ores from different parts of a mine, mass of water added to form a
hydrotransport
slurry, temperature of water to form a hydrotransport slurry, mass of caustic
added to a slurry,
and mass of another additive added to a slurry.
[0061] In the category of primary separation cell (PSC), the following
are mentioned:
slurry dilution water rate and temperature added, PSC underwash flow rate and
temperature,
middlings withdrawal rate, middlings displacement rate (re-injecting flotation
tailings into
PSC), and additive injection rate into PSC.
[0062] In the category of tailings treatment, the following are
mentioned: blending
ratio of multiple tailings streams ahead of subsequent treatment, flocculant
addition rate,
addition rate of another chemical (e.g. a coagulant), thickener operating
parameters (e.g.
feedwell dilution, rake speed, or residence time), in-line flocculant
operating parameters (e.g.
dynamic mixer speed), and a decision about whether to by-pass tailings
treatment process (if
tailings materials are determined to be off-specification).
[0063] In the category of solvent based extraction, the following are
mentioned:
blending ratio of ores from different parts of a mine, mass ratio of solvent
mixed with ore, and
mass of water added to a solvent ore slurry.
[0064] The process adjustment may be adjustment of polymer dosage,
caustic dosage,
or blending ratio with another oil sand stream. The process adjustment may be
adjustment to
achieve a sands to fines ratio (SFR) of a resultant tailings stream within a
predetermined
range. The process adjustment may be adjustment of a flocculant addition rate.
The process
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adjustment may be adjustment to achieve 0-44 um particle content of a
hydrotransport slurry
within a predetermined range. The process adjustment may be adjustment of a
caustic dosage
to a hydrotransport slurry based on reference data.
[0065] The ratio of aluminum to silicon may combined with an indication
of density
and/or flow rate of the oil sand stream to determine a direction and/or
quantity of adjustment
to be made to the parameter in the oil sand treatment process.
[0066] It should be understood that numerous changes, modifications, and
alternatives
to the preceding disclosure can be made without departing from the scope of
the disclosure.
The preceding description, therefore, is not meant to limit the scope of the
disclosure. Rather,
the scope of the disclosure is to be determined only by the appended claims
and their
equivalents. It is also contemplated that structures and features in the
present examples can be
altered, rearranged, substituted, deleted, duplicated, combined, or added to
each other.
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