Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
- BACKGROUND OF THE INVENTION 13 3 4 5 8 4
The present invention relates to the recovery of
bitumen and bitumen wetted minerals from a mixture of
bitumen, water, bitumen wetted minerals and water
wetted minerals.
This invention is primarily concerned with
increasing the particle size of bitumen and bitumen
wetted minerals in mixtures from mined oil sands, from
tailings of mined oil sands plants, from tailings pond
sludge of mined oil sands plants, from heavy oil, water
and minerals mixtures of oil wells, from bitumen and
water mixed with ore of mineral mines and from bitumen
and water mixed with materials of placer deposits. The
invention is particularly concerned with making it
easier to recover bitumen and bitumen wetted minerals
from such mixtures. The invention is also concerned
with making it easier to recover residual bitumen and
bitumen wetted minerals from such mixtures after an
initial amount of bitumen and bitumen wetted minerals
have previously been recovered from such mixtures.
The invention is also concerned with removing
hydrophilic minerals from the bitumen phase of mixtures
of bitumen, bitumen wetted minerals and water wetted
minerals with an excess of water.
Extensive deposits of oil sands, which are also
known as tar sands or bituminous sands, are found in
Northern Alberta Canada and in many other parts of the
world including the USA, Venezuela, and in various
countries of Africa and Asia, including the USSR.
The sands are composed of siliceous material with
grains generally having a size greater than that
passing a 325 mesh screen (44 microns) and a relatively
heavy viscous petroleum called bitumen, which at least
partly fills the voids between the grains in quantities
from 2 to 25 percent of total composition. (All
~'.
133~584
-- percentages referred herein are in weight percent
unless noted otherwise)
Generally the bitumen content of sand that is
mined commercially is between 8 and 15 percent. This
bitumen contains typically 4.5 percent sulfur and 38
percent aromatics. Its specific gravity at 15 degrees
C. ranges generally from about 1.0 to about 1.1. The
oil sands also contain clay and silt. Silt is defined
as siliceous material which will pass a 325 mesh
screen, but which is larger than 2 microns. Clay is
material smaller than 2 microns, including some
siliceous material of that size. In some cases the oil
sands also contain a small percentage of heavy minerals
including ilmenite, rutile, zircon and other metallic
minerals.
Much of the world resource of bitumen and heavy
oil is deeply buried by overburden. For example it
has been estimated that less than 10 percent of the
Alberta oil sand deposit is close enough to the earth s
surface to be conveniently recovered by surface mining.
The remainder is buried too deeply to be economically
strip mined with current technology. Hydraulic mining
has been proposed for those deposits. Generally,
however, it is considered that enhanced recovery by
steam injection, by injection of aqueous solutions, or
by in-situ combustion may possibly be more effective
for obtaining bitumen from deeply buried formations.
Such enhanced recovery methods use one or more oil
wells that penetrate the formation and stimulate the
flow of bitumen or heavy oil to a recovery well. In
some cases, the same well may be used to stimulate and
recover the resource. Depending upon the procedure
employed, enhanced recovery methods generally produce
mixtures of water, bitumen and some sand and minerals
and they recover a lower percentage of the bitumen in
place than mining methods.
- 133458~
~ There are several well known procedures for
separating bitumen from mined oil sands. In a hot
water process, such as disclosed in Canadian Patent No.
841,581 issued 12 May 1979 to Paul H. Floyd et al.; the
bituminous sands are jetted with steam and mulled with
a minor amount of hot water and sodium hydroxide in a
conditioning drum to produce a pulp which passes from
the conditioning drum through a screen, which removes
debris, rocks and oversize lumps, to a sump where it is
diluted with additional water. It is hereafter carried
into a separation cell. In the separation cell, sand
settles to the bottom as primary tailings which are
discarded. Bitumen rises to the top of the cell in the
form of a bituminous froth which is called the primary
froth product. An aqueous middlings layer containing
some mineral and bitumen is formed between these
layers. A scavenging step is normally conducted on
this middlings layer in a separate flotation zone. In
this scavenging step the middlings are aerated so as to
produce a secondary tailings product, which is
discarded, and a secondary froth product.
The secondary froth product is treated to remove
some of its water and mineral matter content and is
thereafter combined with the primary froth for further
treatment. This combined froth typically contains
about 52 percent bitumen, 6 percent minerals, 41
percent water, all by weight, and may contain from 20
to 70 volume percent air. It resembles a liquid foam
and is usually treated with steam to improve its flow
characteristics for subsequent processing. The primary
and secondary tailings products are usually combined
and water may be added to enhance the pipeline disposal
of this combined tailings stream called the extraction
tailings.
The high water and minerals contents of the
combined froth product normally are reduced by diluting
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it with hydrocarbon diluent such as naphtha. It is
then centrifuged to produce a tailings product, called
the centrifugal tailings, and a final bitumen product
that typically contains essentially no water and less
than 1.0 percent solids. The naphtha is recovered from
the final bitumen product which then is suitable for
coking, hydrovisbreaking or other refining techniques
to produce a synthetic crude oil. The centrifugal
tailings, containing some naphtha, bitumen, silt, clay
and heavy minerals are discarded.
There are basically three effluent streams from
the hot water process. Each carries with it some of
the bitumen from the feed; thereby reducing the
efficiency of the process. These include the oversize
materials coming from the screen, the extraction
tailings and the centrifugal tailings. Up to 10
percent of the bitumen in the original feed and up to
2.5 percent of the naphtha stream may be lost in this
manner. Much of this lost bitumen finds its way into
large retention ponds or tailings ponds that are
typical of the hot water process. The bottom of such
retention ponds may contain from 20 to to 50 percent
dispersed mineral matter substantially of clay and silt
as well as 2 percent or more bitumen. As disclosed in
Canadian Patent No. 975,697 issued on 7 October 1975 to
David H. James this part of the pond contents, referred
to as sludge, or tailings pond sludge, is a potential
source of recoverable bitumen.
In the hot water process the heavy minerals
present in the oil sand ore tend to be attracted to and
wetted by the bitumen of the oil sands during
processing, and these heavy minerals are recovered in
the combined bitumen froth product. The minerals are
removed from this bitumen product in the dilution
centrifuging step and are part of the centrifugal
tailings of the hot water process.
1334584
I have found that the extraction tailings from the
hot water process contain heavy minerals as well.
These heavy minerals are in association with and are
wetted by the bitumen that is discarded with the
extraction tailings. I have discovered that this
residual bitumen generally contains a higher percentage
of heavy minerals than the bitumen froth produced by
the hot water process. I have concluded that most of
the bitumen that remains with the extraction tailings
of the hot water process is there for a reason. It is
there because this bitumen does not float as readily as
the bitumen that is recovered. The increased amount of
minerals associated with this bitumen make it denser
and more difficult to float than the bitumen that is
normally recovered in the flotation steps of the hot
water process. Then, when this residual bitumen is
recovered from these extraction tailings, by an
apertured oleophilic belt separation process, which
does not rely on flotation alone, the resulting bitumen
product contains a large amount of heavy minerals.
When Alberta oil sands are mixed with water and
are separated with an apertured oleophilic belt, the
bitumen product contains heavy minerals which are
bitumen wetted and the water phase contains sand, silt
and clay that are water wetted. When extraction
tailings from a hot water process are separated with an
apertured belt to recover the residual bitumen, the
bitumen product from that separation contains heavy
minerals which are bitumen wetted and the water phase
contains sand, silt and clay that are water wetted.
Similarly, when tailings pond sludge is separated with
an apertured belt, the bitumen product from that
separation contains heavy minerals which are bitumen
wetted and the water phase of the sludge contains silt
and clay that are water wetted. Therefore, when a
mixture is separated with an apertured oleophilic belt,
- 1334584
the bitumen wetted minerals are recovered along with
the bitumen phase and the water wetted minerals are
discarded with the water phase. As more bitumen is
recovered from such a mixture, more heavy minerals are
recovered from the mixture as well.
The present invention serves to assist in
recovering bitumen and also to assist in concentrating
heavy minerals from a mixture by capturing these with
the bitumen product. These minerals are released when
the bitumen product is diluted and centrifuged, or when
the bitumen is removed from these minerals in some
other way. Heavy minerals are found in small
concentration of about 1% in the Alberta oil sands.
Oil sands from other locations may contain traces of
other types of minerals, including gold, silver,
platinum and other useful or precious minerals. These
minerals in many cases are or become bitumen wetted in
the process of the present invention and are recovered
with the bitumen. They can be separated from that
bitumen to yield a minerals by-product of the
extraction process.
The present invention may also be used to assist
in recovering useful minerals from other ores. Bitumen
and water may be mixed with ore from a mine to cause
the minerals of the ore to become bitumen wetted while
the gangue becomes water wetted. In a subsequent
separation by an apertured oleophilic belt of this ore-
bitumen-water mixture, the resulting bitumen product
will contain bitumen wetted mineral of the ore for
recovery, and the water effluent will contain water
wetted gangue of the ore to be discarded. On other
occasions bitumen and, if required, water may be mixed
with a placer deposit of minerals, metals or precious
stones to cause these to become bitumen wetted and the
gangue to remain water wetted. In subsequent
separation, by the apertured oleophilic belt of this
133458~
placer deposit mixture, the resulting bitumen product
will contain bitumen wetted minerals, metals or
precious stones of the placer deposit for recovery, and
the water effluent will contain water wetted gangue of
the placer deposit for disposal. The useful
minerals, metals or stones are subsequently recovered
by removing bitumen from the product and/or by burning
off the residual carbon. The resulting minerals
residue may then be separated into components by
mineralogical methods. The mineral recovery aspects of
the present invention may in time be used in
combination with an apertured oleophilic belt to
compete with conventional minerals froth flotation,
with the added advantage that mineral particles of
larger size may be recovered more efficiently.
OBJECTIVES OF THE PRESENT INVENTION
The present invention applies to a method for
recovering bitumen and bitumen wetted minerals from a
mixture of bitumen, water, water wetted minerals and
bitumen wetted minerals with an apertured oleophilic
endless moving belt. The invention specifically
applies to a method for increasing the size of bitumen
particles and bitumen wetted mineral particles in said
mixture to improve primary recovery of these particles
by an apertured oleophilic endless moving belt. The
present invention also applies to a method for
increasing the size of bitumen particles and bitumen
wetted particles in said mixture to improve secondary
recovery of these particles by an apertured oleophilic
endless moving belt. The present invention further
applies to the removal of hydrophilic minerals from
bitumen in mixtures of bitumen, bitumen wetted
minerals, water and water wetted minerals.
1334584
When a mixture of bitumen, bitumen wetted
minerals, water and water wetted minerals comes in
contact with the surfaces of an apertured oleophilic
endless moving belt, these surfaces capture particles
of bitumen and bitumen wetted minerals from this
mixture in a separation zone, while water and water
wetted minerals flow through the belt apertures. These
captured bitumen and bitumen wetted mineral particles
accumulate on the belt in the form of a bitumen phase
and are carried or conveyed continuously by the moving
belt from the separation zone to a recovery zone where
bitumen phase is removed from the belt.
When these bitumen particles and these bitumen
wetted and bitumen coated mineral particles are very
small, they are less likely to come in contact with the
surfaces of the apertured oleophilic belt, and more
likely to pass through the apertures, than when they
are large. It is an objective of the present invention
to increase the particle size of these bitumen
particles and of these bitumen wetted mineral particles
so that the likelihood is improved of them being
captured by the apertured oleophilic endless moving
belt, in a first pass through the belt.
When a mixture of bitumen, water, water wetted
minerals and bitumen wetted minerals mixture is passed
to an apertured oleophilic endless moving belt, without
the mixture having been treated to thus increase the
particle size, the mixture that passes through the
apertures of such a belt may contain a considerable
number of small bitumen particles and small bitumen
wetted mineral particles. It is a further objective of
the present invention to increase the size of these
small bitumen particles and of these small bitumen
wetted mineral particles so that they are more easily
recovered when this mixture containing these particles
133~584
is passed through an apertured oleophilic endless
moving belt for the second time.
Furthermore, a bitumen product, containing
bitumen, bitumen wetted minerals, water wetted minerals
and an excess of water, may be processed by the method
of the present invention to remove water wetted
minerals from the bitumen phase and improve the quality
of the bitumen phase that is subsequently separated
from the mixture with an apertured oleophilic belt.
BRIEF DESCRIPTION OF THE INVENTION
The present invention applies to a method of
increasing the particle size of bitumen particles and
of bitumen wetted minerals particles of a mixture of
water, bitumen, bitumen wetted minerals and water
wetted minerals by contacting these particles in a
novel way with oleophilic surfaces in a revolving drum.
In one aspect, the invention provides a method for
increasing the mean particle size of bitumen and
bitumen wetted mineral particles in a feed mixture of
bitumen, water, bitumen wetted minerals, and water
wetted minerals, which comprises the steps of:
a) introducing said feed mixture into a rotating
drum that contains an abundance of oleophilic
mechanical surfaces, said drum rotating at a rate not
exceeding the critical rotation rate and said
oleophilic surfaces rotating in fixed relationship with
the walls of said drum,
b) tumbling said mixture in the rotating drum so
that said oleophilic surfaces continually pass through
said mixture and come in contact with said bitumen
particles and with said bitumen wetted mineral
particles causing said particles to unite to form
bitumen phase particles that are larger in size than
13~4584
the particles of bitumen in the feed mixture initially
introduced into said drum, and
c) removing tumbled mixture containing said
enlarged bitumen phase particles from said drum.
Increasing the size of the bitumen particles renders
the mixture more suitable for subsequent separation of
bitumen phase from aqueous phase with an apertured
oleophilic endless moving belt or with an apertured
oleophilic moving wall.
In another aspect the invention provides a method
for removing water wetted minerals from the bitumen
phase of a feed mixture consisting of bitumen, bitumen
wetted minerals,water wetted minerals and which
comprises the steps of:
a) introducing said feed mixture into a rotating
drum that contains an abundance of oleophilic surfaces,
said drum rotating at a rate not exceeding the critical
rotation rate and said oleophilic surfaces rotating in
fixed relationship with the walls of said drum,
b) tumbling said feed mixture in the rotating
drum with said oleophilic surfaces causing water wetted
minerals in the bitumen phase of the mixture to be
exposed and causing these minerals to become part of
the aqueous phase of said mixture,
c) separating said tumbled mixture with an
apertured oleophilic endless moving belt or with an
apertured oleophilic moving wall into a bitumen phase
product and an aqueous phase effluent. As a
consequence of the tumbling the bitumen phase product
contains a lower percentage of minerals than the
bitumen phase of the feed mixture that enters said
drum.
In yet another aspect the invention provides an
apparatus for increasing the mean particle size of
bitumen and bitumen wetted mineral particles in a feed
mixture of bitumen, water, bitumen wetted minerals and
133~584
water wetted minerals, or for removing water wetted
minerals from the bitumen phase of such a feed mixture
in the presence of extra water, which apparatus
comprises:
a) a generally horizontal rotatable drum
containing an abundance of mechanical oleophilic
surfaces that are in fixed relationship with the inside
walls of said drum,
b) a means for entry of feed mixture into said
drum and a means for exit of tumbled mixture from said
drum.
c) a means for rotating said drum and a means
for supporting said rotatable drum
In the present invention the oleophilic surfaces
are attached to the drum interior and/or revolve in
fixed relationship with the drum interior walls and
continually pass through the mixture as the drum
revolves. The mixture comes in intimate contact with
these oleophilic surfaces. The bitumen particles and
the bitumen wetted mineral particles adhere to said
surfaces until they have accumulated in sufficient
thickness that the forces in the drum cause flow or
sloughing off of enlarged bitumen particles and
enlarged bitumen wetted mineral particles from these
oleophilic surfaces. These enlarged particles
returning to the mixture may contact other bitumen and
bitumen wetted mineral particles and other oleophilic
surfaces and adhere to them as the mixture passes
through the drum. The mixture, containing enlarged
bitumen particles and enlarged mineral particles,
emerging from the drum, is more readily separated into
a bitumen phase and a water phase with an apertured
oleophilic endless belt than the mixture that enters
this drum.
In one preferred form the process of the present
invention may be used to increase the bitumen and
13~1584
~ bitumen wetted minerals particle size prior to a
primary separation with the apertured oleophilic
endless belt. In another preferred form it may be used
to increase the bitumen and bitumen wetted minerals
particle size of a mixture that has already passed
through an apertured oleophilic endless belt so that
more bitumen and bitumen wetted minerals can be
recovered from the mixture when it is passed to an
apertured oleophilic belt for the second time.
In another preferred embodiment of the invention,
the bitumen phase of a feed mixture is tumbled in the
drum of the present invention in the presence of
sufficient water. The resulting adhesion of bitumen
phase of this mixture to the oleophilic surfaces in the
drum and the shedding, flow or sloughing off of bitumen
from these surfaces in the revolving drum serve to
expose water wetted minerals present in this bitumen
phase and cause these to transfer from the bitumen
phase to the water phase for subsequent separation by
an apertured oleophilic endless belt.
DRAWINGS
The invention will be further illustrated with
reference to the accompnaying drawings showing, by way
of example, embodiments of the invention, in which:
Figure 1 is a perspective view of a typical drum
of the present invention.
Figure 2 is in inside view of a typical drum of
the present invention using a charge of tightly packed
oleophilic column packings to provide the oleophilic
surfaces of the invention.
Figure 3 is an inside view of a typical drum of
the present invention using oleophilic ropes or rods on
a structure inside the drum to provide the oleophilic
surfaces of the invention.
12
1334584
-
69606-38
Figure 4 is a crosæ sectional view of the drum of Figure
3 to show the grating supports and the location of oleophilic
ropes or rods of the present invention.
Figures 5 and 6 are illustrations of how the oleophilic
ropes of the present invention are attached to the grating
supports.
Figure 7 is a cross sectional view of a typical rotary
seal for permitting mixture to enter or leave the revolving drums
of the present invention.
Figure 8 is a cross sectional view of a drum with an
apertured cylindrical wall, around which is placed an apertured
oleophilic endless belt.
Figure 9 is a side view of the drum of Figure 8, and
Figure 10 is a detail drawing of a section of the cylindrical drum
wall and the endless belt of Figure 8.
Figure 11 is a flow diagram of a typical process using
the drums of the present invention.
PRIOR ART
The use of apertured oleophilic endless belts or walls
to separate bitumen phase from water phase has been taught in
Canadian Patents: 1,085,760 issued on 16 September 1980;
1,129,363 issued on 10 August 1982; 1,132,473 issued on
28 September 1982; 1,141,319 issued on 15 February 1983; 1,241,297
issued on 30 September 1988; 1,243,984 issued on 1 November 1988;
1,280,075 issued on 12 February 1991 and 1,288,058 issued on
27 August 1991, all to me.
The use of oleophilic free bodies to increase particle
a~
- 1334584 6g606-38
size of bitumen in a revolving drum has been taught in Canadian
Patents 1,144,498 issued on 12 April 1983; 1,167,792 issued on
22 May 1984; 1,241,297 issued on 30 September 1988 and 1,243,984
issued on 1 November 1988, 1,280,075 issued on 12 February 1991
and 1,288,058 issued on 27 August 1991, all to me.
In the prior art, mechanical free bodies, with oleo-
philic surfaces, tumbling in a drum were used to increase the
particle size of bitumen particles suspended in aqueous mixtures.
In the present invention mechanical bodies with oleophilic
surfaces do not tumble in the drum but are part of the drum
interior and revolve in unison with the drum walls. They are
fixed with respect to the drum interior, either by attachment or
by being tightly packed in the drum and prevented from tumbling by
constraint of baffles, protrusions or roughness on the drum walls.
Mixtures containing water, bitumen, water wetted minerals and
bitumen wetted minerals are tumbled in this drum, and oleophilic
surfaces revolving in thus constrained relationship with the walls
of this drum pass through the tumbling mixture due to the revolu-
tions of the drum.
Thus in the prior art the particle size of bitumen
particles in an aqueous mixture was increased by tumbling free
bodies with the mixture in a drum, which bodies accumulated
bitumen on their surfaces and then shed this accumulated bitumen
back into the mixture in the drum in the form of enlarged bitumen
particles. However, in the present invention the particle size of
bitumen and bitumen wetted and coated minerals is increased by
mechanical oleophilic surfaces in a revolving drum, that are flxed
- 1334584
69606-38
with respect to the drum interior. As these surfaces revolve
through the mixture in the drum, bitumen phase accumulates on
these fixed surfaces and returns back into the mixture in the form
14a
.~
1334584
of enlarged bitumen phase particles. The present
invention therefore uses a different mechanism to
achieve similar objectives as the prior art.
During engineering scale up work of the prior art
it was discovered that for use with cold mixtures, the
free bodies had to have relatively high densities to
achieve effective tumbling in the presence of viscous
cold bitumen. It was further found that, due to the
very large volumes of feedstock handled in a mined oil
sands plant, the commercial size drums required for the
prior art required a very large mass of heavy free
bodies with commensurate high drum strength
requirements, high bearing support requirements and
high turning energy requirements. In the present
invention the objectives of the prior art can be
achieved with drums that have thinner walls, require
lighter bearing supports and use less power to revolve
or turn the drums.
Furthermore, the tumbling free bodies at times
resulted in splashing in the drum of the prior art as
free bodies fell down from the walls of the drum into
the mixture, causing a redispersion and reduction of
bitumen particle size in the mixture. Such splashing,
due to falling mechanical bodies does not take place in
the drum of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
For the purpose of the present invention, bitumen
is defined as a hydrocarbon that at 15 degrees C. has a
viscosity between 1,000 and 50,000,000 centipoises.
Preferably the viscosity is in the range of 10,000 to
5,000,000 centipoises, more preferably 50,000 to
1,500,000 centipoises. Bitumen may include
conventional bitumen, conventional heavy oil, tar, wax,
asphalt, any other thick or viscous petroleum or oil
based fraction or product, or residues from land or
marine oil spills.
Bitumen wetted minerals are defined for the
purpose of the present invention as any number of
mineral particles at least a portion of whose surface
areas are oleophilic and covered by bitumen, or have
become oleophilic and covered by bitumen due to
exposure to bitumen and water. When the surface area
portion covered by bitumen of a mineral particle is
large enough to cause adhesion of this particle on
contact to bitumen on a mechanical surface, such as an
apertured oleophilic belt, or an oleophilic drum
interior surface, the mineral particle is considered to
be bitumen wetted for the purpose of the present
inventlon .
Water wetted minerals are defined for the purpose
of the present invention as any number of mineral
particles most of whose surface areas are hydrophilic
and covered with water or have become hydrophilic and
covered with water due to exposure to bitumen and
water, which mineral particles have no bitumen on their
surfaces, or the surface portions of the particle
covered by bitumen are not large enough to cause these
mineral particles to adhere to bitumen on a mechanical
surface on contact.
Critical rotation rate of a drum is a rate of
rotation where at the apex of the drum the centrifugal
force on a particle at the inside drum surface is equal
to the force of gravity on that particle. This rate of
rotation is a function of the radius of rotation of
that particle, and hence of the inside drum diameter.
The drums of the present invention do not rotate at
rates in excess of the critical rotation rate; they
normally rotate a rates less than 30% of the critical
rotation rate, and for most mixtures they preferably
rotate at rates less than 10~ of the critical rotation
16
133458~
rate. Preferably the drum is at a temperature between
zero and 50 degrees C., more preferably at a
temperature between 10 and 30 degress C.
It is to be understood that the present invention
is used to enhance the separation of bitumen and
bitumen wetted minerals from water and water wetted
minerals with an apertured oleophilic endless belt, no
matter from where they originate. A mixture for
separating, that contains bitumen, water, bitumen
wetted minerals and water wetted minerals, may exist in
that form; or it may be prepared as part of the
separation objective prior to the actual separation.
For example, mined oil sands tailings and tailings pond
sludge are mixtures that normally contain bitumen,
water, bitumen wetted minerals and water wetted
minerals; and these may be separated in the form they
are normally produced or normally exist.
The mixture may have already passed through an
apertured oleophilic endless belt before it is
processed by the present invention. In that case the
mixture is passed through the drum of the present
invention to increase the particle size of residual
bitumen and bitumen wetted mineral particles, still
remaining in the water phase, to increase the
likelihood that the thus enlarged bitumen and mineral
particles are captured by the belt surfaces when these
are introduced to a second apertured oleophilic endless
belt for separation.
Oil sands, as mined, normally contain only very
small amounts of water or no water at all. Water needs
to be added to and mixed with such oil sands to prepare
a mixture suitable for separation by the present
invention. In some cases heat and/or mechanical energy
needs to be added as well to the oil sands, along with
the water; and this mixture needs to be tumbled and
screened to digest the lumps of oil sands in water and
1~3458~
to remove debris, rocks and oversize lumps before it is
prepared for separation by the present invention.
Furthermore, both water and bitumen may be added to
mineral mine ores, and the resulting mixture tumbled,
mixed, ground and screened before these ores are
suitably prepared for separation into bitumen wetted
minerals and water wetted gangue. In a similar way,
bitumen and perhaps water may be added to placer
deposits, tumbled and screened, and perhaps ground,
before it is suitably prepared for separation into
bitumen wetted minerals and water wetted gangue.
Bitumen product from a previous separation,
either by froth flotation or by an apertured oleophilic
belt, containing bitumen, bitumen wetted minerals,
water wetted minerals, water and some extra water, may
be processed by the present invention to cause the
transfer of water wetted minerals from the bitumen
phase to the water phase. As this mixture tumbles in
the drum of the present invention the continual
adhesion of bitumen to the oleophilic drum surfaces and
the continual shedding of such bitumen from these drum
surfaces in the presence of said mixture causes water
wetted minerals, that previously were part of the
bitumen phase, to be released and become part of the
water phase. When this mixture is then separated
subsequently by an apertured oleophilic endless belt,
the resulting bitumen product contains a reduced amount
of water wetted minerals.
For the purpose of the present invention, extra
water is defined as water that is added to the mixture
to reduce the minerals content of the aqueous phase and
to facilitate the transfer of water wetted minerals
from the bitumen phase to the aqueous phase in one
embodiment of the invention. Normally this extra water
is added in the recovery zone of an apertured
oleophilic belt separator to help remove bitumen phase
18
133~584
from the top flight of this belt. It may also be added
to the drum of the present invention for the purpose of
reducing the mineral content of the aqueous phase of
the mixture and thereby encourage the transfer of water
wetted minerals from the bitumen phase to the aqueous
phase. Extra water normally becomes part of the free
water that is not emulsified with the bitumen phase of
the mixture.
I have discovered that when a mixture of bitumen,
bitumen wetted minerals, water and water wetted
minerals are passed to an apertured oleophilic wall in
a separation zone, the bitumen and bitumen wetted
minerals will cling to this wall when they come in
contact with it but the water and the water wetted
minerals will pass through the wall apertures. When
this wall is stationary, only a relatively small amount
of bitumen and bitumen wetted minerals can be collected
in this manner since the bitumen and bitumen wetted
minerals accumulating on the wall surfaces will close
the apertures. However, when the wall is moving, and
bitumen and minerals are removed from the wall, more
mixture can be separated in this manner without danger
of closing the apertures. Furthermore, when the wall
is a moving endless belt that has at least one
separation zone for separating the mixture in these two
phases and at least one recovery zone for removing the
clinging bitumen and bitumen wetted minerals from the
belt surfaces and out of the belt apertures, the
process becomes continuous and large amounts of mixture
can be separated per day or per year by the moving belt
on a continuous basis.
I have found that optimum separation is achieved
by an apertured oleophilic endless belt when the
bitumen particles and bitumen wetted particles of the
mixture, that flow to the belt, are large enough that
most of them contact the surfaces of the endless belt
1334584
-- as the aqueous phase passes through the belt apertures.
When the bitumen particles are too small, the
probability of them being captured by the belt surfaces
is low. They tend to pass through the belt apertures
with the aqueous phase without contacting the belt
surfaces, and remain part of the aqueous mixture
leaving the separation zone. Reducing the aperture
size of an apertured oleophilic endless belt increases
the probability of bitumen coming in contact with these
belt surfaces, but in many cases other factors, such as
mineral particle size in the mixture, make it
undesirable to reduce the aperture size of the belt.
I have further found that small bitumen particles
and bitumen wetted mineral particles suspended in an
aqueous mixture may be increased in size by tumbling
this mixture in a drum with oleophilic surfaces. The
oleophilic drum surfaces capture these small bitumen
and mineral particles so that they form a layer on
those surfaces that progressively increases in
thickness until it becomes too thick to sustain itself
in the presence of gravity forces in the drum and shear
forces in the tumbling mixture. These forces cause a
flowing off or a sloughing off of enlarged bitumen
particles and enlarged bitumen wetted mineral particles
from the oleophilic drum surfaces. The enlarged
bitumen and mineral particles, thus returning to the
mixture, may continue to tumble in the drum, may
capture additional bitumen and minerals, may be
captured by other oleophilic drum surfaces and, may
flow from these surfaces when they reach the exit of
the drum. In addition, the bitumen and bitumen wetted
minerals may flow along the mechanical surfaces in the
drum interior and flow therefrom when they reach the
drum exit. I have found that the resulting mixture
that emerges from this drum contains bitumen particles
and bitumen wetted mineral particles that are much
1334584
- large than the bitumen particles and bitumen wetted
mineral particles contained in the mixture that enters
this drum.
I have further found that when a bitumen product,
containing bitumen, bitumen wetted minerals and excess
water is tumbled in a drum with oleophilic surfaces,
the repeated adhesion and shedding of bitumen and
bitumen wetted minerals to and from oleophilic internal
drum surfaces in the presence of excess water causes
water wetted minerals, present in the bitumen phase, to
be exposed to the aqueous phase of the mixture. This
exposure in the tumbling mixture causes a transfer of
water wetted minerals from the bitumen phase to the
aqueous phase. Subsequent separation with an apertured
oleophilic endless belt of this tumbled mixture results
in a bitumen phase that contains less water wetted
minerals than the bitumen phase that entered the drum.
When a mixture entering the drum contains a relatively
low water content, and a correspondingly high water
wetted minerals content, water may have to be added to
the drum to enhance the transfer of water wetted
minerals from the bitumen phase to the aqueous phase by
the oleophilic drum surfaces. In that case the final
bitumen phase may contain a higher percentage of water
than the bitumen phase that entered the drum, but it
usually contains a much lower percentage of minerals.
A drum of the present invention is illustrated in
Figure 1. Mixture to be processed enters the revolving
drum from a stationary pipe (13) and a rotary seal (12)
and leaves the drum through a rotary seal (14) to a
stationary pipe (15). The drum (l) has a front wall
(9), a cylindrical side wall (10) and a rear wall (11).
The front and rear walls may be straight, coned or
dished. Trunnion rings (2) may be mounted on the drum
side wall (10) to support the drum on four revolving
rollers (3) and revolve the drum. These rollers (3)
- 1~34584
- are mounted on shafts (4) supported in bearings in
pillow blocks (5). At least one of these shafts (4) is
driven by an electric motor (7) through a gear box
(6), or the drum is driven by a motor with sprockets
and a chains or by a hydraulic motor. The roller
assembly is mounted on a steel base (8) to support the
drum (1) in a stable manner. A cut out (16) is shown
in Figure 1 to show column packings (18) with
oleophilic surfaces that pass through the mixture (17)
as the drum tumbles. The mixture (17) level in the
drum is preferably maintained at approximately the mid
point of the drum cross section, filling the free
volume of the drum to 50%. However, it may average as
low as 30% or as high as 70% of the free volume of the
drum, by tilting the drum (1), by increasing the size
of the rotary seals (12 and 14) of the drum, or by
separately controlling the inlet and outlet pressure
while weighing the drum and its contents. Instead of
trunnion rings and rollers, the drum may be supported
by bearings.
An inside view of Figure 1 is shown in Figure 2.
The drum is tightly packed with oleophilic column
packings (18) that were loaded into the drum through
the drum flanges (21) and closure plates (51) of the
inlet distributor (25) or the outlet distributor (26)
at either end of the drum (1). These column packings
are of low density and typically are made from a
plastic material such as polypropylene that is
oleophilic and that has good abrasion resistance. They
are tightly packed into the drum and the drum interior
is baffled or roughened on purpose so that when the
drum revolves, the tower packings do not slide or
tumble but remain stationary with respect to the drum
walls. However, the drum packings (18) have large
openings through which the mixture (17) can pass as the
drum revolves. Mixture enters the drum from a
~ stationary pipe (13), through a rotary seal (12), 133 58
through drum flanges (21) and through the apertured
walls of the inlet distributor (25). It passes through
the tower packings (18) in the drum (1) inside and then
leaves the drum through the apertured wall of the of
the outlet distributor (26), through drum flanges (21),
through a rotary seal (14) and to a stationary pipe
(15).
An alternative inside of a drum of the present
invention is shown in Figure 3 where oleophilic ropes,
rods, pipes or strands are used instead of oleophilic
column packings. Mixture enters this drum from a
stationary pipe (13), through a rotary seal (12),
through drum flanges (21) and then flows into the drum
interior where it passes by a structure that supports
long oleophilic members (24), such as oleophilic ropes,
strands, rods or pipes. It tumbles past those
oleophilic members (24) through the revolving drum (1)
and leaves the drum through drum flanges (21), through
a rotary seal (14) and to a stationary pipe (15). The
oleophilic members (24) are supported by steel flat bar
grating or molded flat bar plastic grating (27) that
allow for uniform spacing of the oleophilic members
over the cross section of the drum (1). This grating
is supported by an angle iron ring (28) and channels or
I beams (19) that are attached to a steel pipe (20) to
form a strong structure to support the oleophilic
members throughout the drum (1). Panels of grating
(27) may also be mounted at the mid point of the drum
inside, or at other locations along the the pipe (20)
wall to maintain even and uniform spacing of the
oleophilic members (27) throughout the drum cross
section. The central pipe (20) is closed at one or both
ends to prevent flow of mixture through the pipe.
One of the end supports for the oleophilic members
is shown in Figure 4. A cross of I beams (19) is
1334584
welded to the main support pipe (20) and an angle iron
ring (28) is welded to the ends of the the I beams
(19). Flat bar steel grating (27) or molded plastic
grating is mounted onto and is supported by the I beam
cross and angle iron ring. Oleophilic members, such as
ropes, strands, bands, rods or pipes pass through the
holes in the grating and/or are attached to the
grating. Perforated steel may be used instead of
grating when pipes or rods are used for the oleophilic
members if the strength of these pipes or rods, and
their resistance to bending, is sufficient. They only
have to be inserted in the perforations of the
perforated steel supports at both the front and the
rear of the drum to remain in place in the drum.
However, when ropes, strands or bands are used for the
oleophilic members, they must be strung tightly between
the front and rear grating supports to obtain a uniform
spacing of oleophilic members throughout the drum cross
section. Compared with perforated steel plate, flat
bar steel grating or molded plastic grating has
smoother edges that are less likely to cut the
oleophilic ropes, strands or bands, and are therefore
preferred when ropes or strands instead of pipes or
rods are used as the oleophilic members.
A method for attaching ropes, strands or bands to
the grating is shown in Figures 5 and 6. These
oleophilic members (24) are looped over the grating
(27) bars and the loops tied together with steel tie
wires t29) that prevent movement of the members and
cause secure attachment of these oleophilic members
(24) to the grating (27), or they are attached with
knots to the grating bars.
A rotary seal for use with the drum of the present
invention is shown in Figure 7. The inner stationary
pipe (31) is attached to the stationary interconnecting
piping with a pipe flange (34), and to the inner race
24
133458~
(38) of a slewing ring bearing or turn table bearing
with a bearing flange (32). The revolving outside pipe
(30) of the rotary seal is attached to the drum front
or rear walls (9 or 11) with a drum flange (21) and to
the outer race (33) of a slewing ring bearing or turn
table bearing with a bearing flange (33). Bolts (35
and 36) are used to attach the inner pipe and the other
pipe to the bearing races.
Three sets of rubber seals may be used to prevent
the flow of mixture out of the drum past the inner pipe
(31). They are kept in place by snap rings (46)
mounted in the outer pipe and with two lantern rings
(44 and 45). The first set of two seals (47) closest
to the drum flange (21) are separated from a second set
of two seals (48) with a lantern ring that allows
grease from a grease nipple (43) to fill the volume
between these two sets of seals and help prevent the
flow of mixture past the inner pipe. A second lantern
ring (45) separates a fifth seal (49) from the second
set of seals (48) to provide an area for leakage flow
to bleed holes (41) in the outer pipe. This fifth seal
(49) and bleed hole (41) largely eliminate leakage into
the space between the inner race (38) and the outer
race (39) of the bearing. However, a second set of
bleed holes (42) are provided in the bearing flange
(33) of the outer pipe. The end (50) of the inner pipe
(31) is tapered to provide for easy insertion of the
inner pipe through the seals without damage to the
seals during assembly. A regular or periodic
replenishment of grease through the grease nipple (43)
lubricates both sets of seals (47 and 48), and
minimizes or eliminates flow of mixture past these
seals. The rotary seal of Figure 7 typically has an
inside diameter 10 to 50 centimeters or more in size.
The bearing used for the rotary seal of Figure 7
typically is a single race four point contact ball
133458~
bearing such as is normally used as the mounting
bearing for small cranes. These bearings are supplied
with drilled flanges for mounting, and they are
designed with suitable internal ball spacings that
permit mounting such bearings in the vertical plane.
They accept radial loads, axial loads and moment loads
and therefore are well suited to give rigidity to the
rotary seal. Normally the inner pipe (31) of the
rotary seal is attached to plant process piping with a
flexible connection, or with a long length of
unsupported pipe, to reduce stresses resulting from
small misalignments of the rotary seal mountings.
The oleophilic column packings that may be used in
the drum of the present invention may be cylindrical
rings, Pall (R) rings, Novalox (R) sadles, Berl sadles
or may be Tri-packs (R) fabricated by Jeager Products
Inc. and described in Canadian patent 1,150,621, or may
be other shapes that are conventionally used as mass
transfer column packings. They may be made from metal
or from plastic and/or they may be coated with an
oleophilic coating. Preferably they are molded from
polypropylene or from other strongly oleophilic and
abrasion resistant plastics.
Figure 8 is a schematic drawing of an apertured
oleophilic belt separator that uses an embodiment of
the present invention to increase the particle size of
bitumen and mineral particles of an aqueous mixture in
direct conjunction with the apertured belt. The drum
of Figure 8 is shown in side view, on a somewhat
smaller scale, in Figure 9. Construction details of
the wall of the drum are shown in Figure 10. The
separator consists of a drum (51), with a central shaft
(52) supported in pillow block bearings (53). The
shaft (52) is hollow and has holes (71) inside the drum
to permit mixture to be pumped into the drum via a
rotary seal (54). Mixture flows into the drum and
26
133~84
leaves the drum through apertures (55) in the
cylindrical drum wall (56) to fill the tank (57)
surrounding the drum (51). As the mixture flows
through the drum apertures (55), it encounters an
apertured oleophilic belt (58) on the exterior of the
cylindrical drum wall (56). Water and water wetted
minerals of the mixture (59) flow through the apertures
(60) of this belt but bitumen (61) and bitumen wetted
minerals adhere to the belt surfaces (73) on contact
and are conveyed by that belt (58) to a recovery zone
(62) where high pressure steam, or high pressure water
from a bank of nozzles (63) blow this bitumen and
minerals from the belt into a bitumen product receiver
(64). The apertured belt (58) is an endless belt,
supported by the drum (51) to form a separation zone,
and by two conveyor rollers (102 and 103) to form a
recovery zone. As the drum (51) revolves continually,
bitumen and minerals are continually conveyed from the
drum wall (56) to the recovery zone (62).
The interior of the drum (51) may be filled with
oleophilic column packings, similar to the drum of
Figure 2. Alternately it is provided with oleophilic
rods, pipes or ropes (65), similar to the drum of
Figure 3. These oleophilic members (65) may be mounted
longitudinally in the drum (51) as in Figure 3, or they
are mounted radially in the drum between a support
structure (66) that is concentric with the drum inlet
(67) and the cylindrical wall (56) of the drum.
The mixture flows from the central inlet (67) of
the drum in a radial direction to the apertures (55) in
its exterior cylindrical wall (56). The oleophilic
pipes, rods, strands or ropes (65) in Figure 8 are
mounted in the drum interior in radial alignment from
the center of the drum to the cylindrical drum wall
(56) in the same general direction as the flow of the
mixture. During operation the drum revolves. The
27
1334584
~ oleophilic surfaces (65) revolve through the mixture
(59) in the drum and bitumen and bitumen wetted
minerals, coming in contact with these oleophilic
members (65), adhere to them. They build up on these
surfaces until the shear forces and gravity forces in
the drum cause a shedding of bitumen and minerals from
these surfaces back into the mixture (59) in the form
of enlarged bitumen particles. A continuous adhesion
and shedding of bitumen and minerals to and from the
oleophilic members of the revolving drum takes place in
the mixture. As a result, bitumen and bitumen wetted
minerals accumulate in the drum (51) and then flow
through the apertures (55) of the drum wall (56) to the
apertured endless belt (58). They are conveyed to the
recovery zone (62) where they collect in the bitumen
receiver (64) and are removed therefrom to further
processing. The bitumen and bitumen wetted minerals
depleted mixture flows into the tank (57) surrounding
the drum and belt, and is pumped from this tank to
disposal or further processing.
Long oleophilic members in the drums of the
present invention, such as pipes, rods, ropes or
strands in Figure 8 are shown placed in the drum in
general alignment with the flow of mixture through the
drum. They may also be place generally perpendicular
to the flow of mixture through the drum.
The cylindrical wall (56) of the drum of Figure 8
may be made from perforated steel, or may may be made
from flat bar grating rolled in the form of a cylinder.
This is shown in more detail in Figure 10. A large
number of angle iron rings (68) are rolled to a
suitable diameter and are placed in parallel about
half a meter apart to form the inside drum (51) wall
supports. Steel flat bar grating (69) is placed over
these inside supports (68), bent into a cylinder and
welded to the angle iron supports to form a very rigid
28
133q584
drum wall (56) with a large percentage open area. End
walls (70), with man holes (not shown), are welded to
this cylindrical wall (56) and a central shaft (52) is
provided that mounts in pillow block bearings (53) to
provide rotatable support for the drum (51). The shaft
(52) is hollow. Holes (71) are made in the shaft (52)
inside the drum. A rotary seal (54) is mounted on one
or both ends of the shaft (52) to accept mixture under
pressure from a stationary pipe. When only one rotary
seal is used to supply mixture to the drum, the other
end of the shaft is blocked to prevent loss of mixture.
Tank walls (72) are provided around the drum, and holes
are provided in these walls to permit passage of the
drum shaft ~52). Seals may be mounted in these holes
to reduce or prevent the loss of mixture from the tank
(57) of the separator whose level (75) preferably is
below the level of the shaft (52) of the drum.
Figure 11 is a flow diagram of a typical process
that uses several embodiments of the present invention.
It is a flow diagram for recovering bitumen and
minerals from tailings pand sludge. It uses three
apertured endless belt separators. It also uses two
drums of the present invention. One drum is used to
increase the particle size of bitumen and bitumen
wetted heavy minerals, and the other drum is used to
remove water and water wetted clay from the bitumen
product of the two first separators. Sludge (76) is
pumped from a tailings pond into the first separator
(77) to recover the bulk of the bitumen and bitumen
wetted minerals from that sludge (76) The bitumen and
minerals depleted sludge (78) is then pumped to a
revolving drum (79) filled with oleophilic column
packings. This drum serves to increase the particle
size of bitumen and bitumen wetted minerals that have
passed through the apertures of the belt of the first
separator (77). After leaving the first drum (79), the
29
133~58~
~~ mixture is pumped to a second separator (80). There
the apertured belt captures the bitumen and minerals
that were increased in size by this drum (79) of the
present invention. After that, the tailings mixture
(82) of the second separator (80) is discarded. The
bitumen and minerals product(83, 84) from both
separators is combined. It is pumped to a second drum
(85) where clay is removed from the bitumen product and
transferred to the water phase. Jets of water from
nozzles (86, 87) are used in the first two separators.
This causes extra water to be mixed with the bitumen
and minerals product (83, 84) of these two separators.
The resulting bitumen product and its extra water (88)
is tumbled in the second drum (85). Using an
embodiment of the present invention, this drum exposes
clay and silt particles from the bitumen phase and
transfers these to the aqueous phase of the mixture.
The tumbled mixture (89) from the second drum (85) then
flows into the third separator (90) where the bitumen
phase is separated from the aqueous phase. Indirect
heat (91) is used in the recovery zone (95) of this
third separator (90), in stead of jets of water or
steam, to remove bitumen from the top flight (92) of
the endless belt. As a result, the bitumen product
(93) from this separator (90) contains much less water
than the product of the previous two separators. This
bitumen product (93) is removed from the third
separator (90) and pumped to further processing. The
aqueous phase tailings (94) from the third separator
(90) are either pumped to the top of a tailings pond
(not shown) for settling of the contained clay and
silt, or it is blended with the sludge feed to the
first or second separator.
In the present invention therefore, bitumen
particles and bitumen wetted mineral particles in an
aqueous mixture are increased in size by tumbling the
1334584
mixture in a drum in the presence of oleophilic
surfaces that do not tumble but that revolve in unison
with the drum interior walls and surfaces. The bitumen
particles and bitumen wetted mineral particles adhere
to the oleophilic surfaces upon contact and accumulate
on these surfaces to form a layer that increases in
thickness until a portion of it sloughs off back into
the mixture, or until it flows out of the drum along
the mechanical oleophilic surfaces. When sloughed off
back into the mixture, it mixes with the bitumen
particles and with the bitumen wetted mineral particles
and is recaptured by oleophilic surfaces. It may
continue to be sloughed off these surfaces until it
reaches the drum exit and flows out with the mixture.
As a result of passing through the drum of the
invention, the mixture that leaves said drum contains
bitumen particles and bitumen wetted mineral particles
that are larger than the bitumen particles and bitumen
wetted mineral particles that enter the drum. The
process is a continuous process with mixture
continuously entering the drum of the invention and
mixture continuously leaving the drum. Generally the
drum is filled with mixture to its mid point but it may
also contain less mixture or more mixture. Compressed
air may be added to the feed of the drum, when the
level of mixture in the drum is higher than desired,
to decrease the level of said mixture. The mixture
coming from the drum is suitable for subsequent
separation with an apertured oleophilic moving endless
belt or with an apertured oleophilic moving wall.
Normally the mixture enters the drum of the present
invention through one end wall. It passes through the
drum interior in a longitudinal direction and leaves
the drum through the other end wall. However, the drum
of the present invention may also form part of an
apertured oleophilic endless belt separator. In that
- 133458~
case the mixture enters through one end wall but it
leaves through apertures in the cylindrical drum wall,
which is covered by an apertured oleophilic endless
belt.
The drum of the present invention may also be used
to improve the quality of bitumen products, such as
bitumen froth from a hot water process, bitumen froth
from other flotation processes, or bitumen product from
an apertured oleophilic endless moving belt. The
bitumen product entering the drum may contain air,
bitumen, bitumen wetted minerals, water and water
wetted minerals. This mixture, as it tumbles with
oleophilic surfaces in the drum becomes deaerated and
the bitumen comes in contact with the mechanical
oleophilic surfaces of the drum. Bitumen and bitumen
wetted minerals, continuously collect on these
oleophilic surfaces and shed from these surfaces. When
extra water is present in the mixture, this adhesion
and shedding of bitumen particles causes exposure of
water wetted minerals from the bitumen phase to water,
and a transfer of them to the aqueous phase of the
mixture. These water wetted minerals thus become part
of the aqueous phase of the mixture and are recovered
with the aqueous phase when the mixture that issues
from the drum is subsequently separated with an
apertured oleophilic endless moving belt. The
resulting bitumen phase product contains a lower
percentage of minerals than the bitumen phase of the
feed to the drum and hence, this embodiment of the
invention has improved the quality of the bitumen
product.
EXAMPLE
Sludge from the tailings pond of a mined oil sands
plant at 5 degrees C. , containing 5% bitumen, 70%
1334584
water and 25% solids composed mainly of clay, is
provided from a pump, submerged 15 meters below the
surface of that pond, to a separator using an apertured
oleophilic moving endless belt. Two hundred cubic
meters of sludge per hour are separated by this belt,
resulting in 20 cubic meters per hour of bitumen
product, consisting of 10% mineral, 30% bitumen and 60%
water. The sludge that has passed through the
apertures of the endless belt of the separator is
pumped to a 2 meter inside diameter, 6 meter long drum
containing a structure supporting six hundred 1
centimeter diameter woven polypropylene ropes, tightly
strung longitudinally between structural supports
inside the drum and uniformly spaced over the drum
cross section. The drum is supported on two trunnion
rings that are 20 centimeter wide and 2.2 meters in
outside diameter resting on four rollers that are
supported on two shafts in bearings in pillow blocks on
a steel frame. One of the two shafts is driven by an
electric motor through a gear box, resulting in drum
rotation of 3 RPM. Sludge enters and leaves this drum
through rotary seals as shown in Figure 7. Sludge
leaving the drum is pumped to a second apertured
oleophilic movin~ endless belt separator, resulting in
approximately 11 cubic meters per hour of bitumen
product consisting of 20 % minerals, 30% bitumen and
50% water. The aqueous phase from this second
separator is considered spent sludge and is sent to
disposal to a new holding pond in a mined out portion
of the mined oil sands site. The bitumen product from
both separators is combined and 10 cubic meter of water
per hour and is added to this combined product stream
and is pumped to a 2 meter inside diameter, 6 meter
long drum containing a structure supporting six hundred
1 centimeter diameter woven polypropylene ropes,
tightly strung longitudinally in the drum inside and
-
133458~
uniformly spaced over the drum cross section. The drum
is supported on two trunnion rings that are 20
centimeter wide and 2.2 meters in outside diameter
resting on four rollers that are supported on two
shafts in bearings in pillow blocks on a steel frame.
One of the two shafts is driven by an electric motor
through a gear box, resulting in drum rotation of 1
RPM. A third apertured oleophilic moving endless
belt separator is used to separate the product mixture
coming from this second drum. Approximately 15 cubic
meters of bitumen product per hour are produced by the
third separator consisting of 10% mineral, 60% bitumen
and 30% water while approximately 15 cubic meters of
aqueous phase are returned to the top of the original
tailings pond to allow settling of the contained water
wetted solids. The bitumen product from the third
separator is blended with an equal amount of naphtha,
is heated to 150 degrees C. and is pumped to
centrifuges to remove water and minerals. The overflow
of the centrifuges is pumped to a naphtha recovery unit
from where the recovered naphtha is returned for reuse
as a bitumen blend for the centrifuges. The bitumen
product from the naphtha recovery unit is pumped to
coking and upgrading to produce synthetic crude oil.
The underflow from the centrifuges contains mainly
water and minerals with some residual bitumen and
naphtha. This underflow is pumped to a fluidized bed
reactor to flash off the water and naphtha and to burn
off the bitumen and carbon mineral. The hot minerals
from the fluidized reactor are quenched and are
separated by mineralogical methods into heavy minerals
and light minerals and the light minerals are
discarded. The heavy minerals are further processed to
recover titanium and zirconium ore.
1334584
~ Although the invention as has been described is
deemed to be that which forms the preferred embodiments
thereof, it is recognized that departures may be made
therefrom and still be within the scope of the
invention which is not to be limited to the details
disclosed but is to be accorded the full scope of the
claims so as to include any and all equivalent methods
and apparatus.
For example, in the aspect of the invention for
removing water wetted minerals from the bitumen phase
of a feed mixture, extra water may be part of the
mixture, it may be added to the mixture before it
enters the drum, or it may be added to the mixture in
the drum. A high water content, a low minerals content
in the water phase and a high water wetted or water
wetable minerals content in the bitumen phase of the
mixture will result in the transfer of minerals from
the bitumen phase to the water phase of that mixture
during the process of the invention. This is because
low minerals content in the water phase in the drum of
the present invention encourages water wetted minerals
to leave the bitumen phase and become part of the water
phase. Tumbling such a mixture in the drum of the
present invention encourages water wetable minerals in
the bitumen phase to become water wetted.
