Note: Descriptions are shown in the official language in which they were submitted.
PROCESS FOR RECOVERING MINERALS
FROM MIXTURES CONTAINING THE SAME
BACKGROUND OF THE INVENTION
Industrial nations are constantly
increasing their metal consumption and the known
supply of metal, and particularly copper, lead
and zinc is shrinking and in a few years the
metal industry may not be able to supply the
world needs. There are, however, still large
quantities of minerals in very low grade ore
that have been hereto untouched because of the
difficulty in recovering the valuable minerals
from the other solid material which is of little
value.
In the low grade ore, the desired
minerals many times appear only as just a few
specks mixed with other minerals or solids, and
a great amount of material must be handled to
recover the small amount Owe desired mineral.
Any process for recovery of the desired minerals
from low grade ore should involve as few handling
steps as possible.
In addition, there has been difficulty
I 3
1 in developing processes that can detect or select
the small amount of mineral from the large amount
of solids of little value generally termed guying.
This operation known as ore dressing generally
involves comminution or fragmentation of the ore
to small size to permit easy separation of the
different kinds of solids, followed by one or more
sorting operations designed to distinguish and
separate the valuable mineral particles from the
rest. In the past the sorting has generally been
accomplished by techniques, such as, for example,
those based on gravity, magnetism or chemical
attraction or reaction.
The gravity separation processes depend
upon the different rates of fall through water and
are patterned after the simple panning technique
where the particles are swirled with water in a
shallow conical dish with the effect that the dense
particles stratify in the bottom while the lighter
minerals being more buoyant remain partly in suspend
soon and can be decanted with water from time to
time. The modern successors to the panning technique
use more complicated steps and equipment, but the
-3 "$~
1 process is still limited by difficulties of ox-
twining particles of the right size, interference
with walls and bottoms of the containing vessels,
and the like.
The magnetic separation process can be
used for separating only a few minerals. The
most obvious case is that of the ferromagnetic
magnetize and minerals that can be chemically
altered to produce magnetites Such separators
work efficiently only if the material is presented
in rather a thin layer only a few particles deep.
Consequently the design of a high capacity plan
for use with fine material at reasonable cost is
scarcely practicable.
Froth flotation is probably the more
desirable of the sorting processes as it operates
through the sensitive surface properties of the
individual minerals. It is generally applicable
to very fine concentrates and can distinguish not
only ore mineral from guying but one ore mineral
from another. Briefly, conditions are arranged
so that when a mixture is agitated and air bubbles
are blown through it certain minerals attach them-
I
1 selves to the bubbles and are floated out in a
froth which is skimmed off and discharged of
its mineral burden. In many cases the surface
properties of the ore and guying minerals vary
within too narrow a range to be useful for
effective separation, and as a result certain
organic compounds called collectors are added
to bring about more selective adsorption. The
main type of collectors are organic acids, their
;- salts, organic bases and oils, swishes kerosene,
I-- creosotes, diesel or fuel oils. To be effective,
these processes generally require strict control
"
Jo of pi and addition of many additives, such as
conditioners, wetting agents, frothing agents,
.., ...., 5~ C -i which add greatly to the cost, particularly when
treating large quantities of ore. In addition,
the technique requires that the minerals be ground
to very fine particles before an effective swooper-
lion can be accomplished.
It is an object of the present invention,
therefore, to provide a new and improved process
for extracting minerals from mixtures containing
them. It is a further object to provide a process
I I
1 for sorting or extracting valuable minerals from
guying which can be effectively operated on
large quantities of ore, can be operated with
few operational steps, is operative with particles
of great variety of size, is dependent upon very
few process variables and can be made effective
for the separation of a great variety of different
mineral ores.
SUMMARY OF THE INVENTION
It has now been discovered that these
and other objects can be accomplished by the pro-
cuss of the invention which provides a new, improved
and highly efficient technique for recovering
valuable minerals from mixtures containing the
said minerals and particles of little value termed
guying, and particularly low grade ore containing
the minerals. The process comprises (1) insuring
that the mineral particles in the mixture have an
oleophilic surface and such surface is sufficiently
large to be attracted to other oleophilic surfaces,
(2) passing the resulting mixture through an
aperture wall having an oleophilic surface so that
the mineral particles are attracted to the said
1 oleophilic surface and the remaining portion of
the mixture containing the guying passes -through
the apertures, and (3) removing the mineral
particles from the aperture surface. It has
been surprisingly found that by the use of this
unique process one can effect a separation of
small quantities of very fine particles of
mineral from large quantities of ore, and can
effect such a separation with a small number of
operational steps. In addition, the separation
can be effected without the use of large quantities
of expensive additives and without strict control
of reaction conditions, such as phi and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred apparatus to be used in
the process of the invention is that shown in US.
4,236,995 and U. S. 4,224,138. Figure 1 is a per-
spective view showing an apparatus patterned
after that shown in US. 4,224,138 for conducting
the process of the invention wherein the aqueous
slurry containing the water, stream, crushed ore
and oleophilic material is passed through an aver-
lure surface which is in the form of a rotating
I 7
1 belt contained within a water bath.
Figure 2 and PA are views of a section
of an aperture oleophilic sieve belt in the form
of a meshed construction.
Figure 3 is a schematic illustration of
one method for recovering the mineral-oleophilic
material combination from the aperture belt or
disc using two rollers.
DETAILED DESCRIPTION OF THE INVENTION
The first step in the process of the
invention involves insuring that the mineral
particles in the mixture have an oleophilic sun-
face of sufficient area to effect attraction of
the particles to an oleophilic aperture surface.
As used herein "oleophilic" refers to
those surfaces or materials which are attracted
to and wettable with oil, as distinguished from
oleophobic wherein the surfaces are not so
attracted or wetted with oil.
It has been found that precious mineral
particles tend to be naturally oleophilic and have
oleophilic surfaces unless they are coated with
slime or with oxides of iron or other metallic
1 oxides, or with films of hydrophilic matter.
Metals -that are not easily oxidized such as tin
also tend to have oleophilic surfaces. Broadly
speaking sulfide minerals are or can be made to
be oleophilic but oxides, carbonates, silicates
and surfaces are mostly oleophilic. Graphite
is oleophilic, diamonds are hardly oleophilic
and copper is hardly oleophilic. Silver in its
native state is oleophilic.
Gold particles, particularly when
flaky or in piety form have oleophilie surfaces.
In some cases, the gold particles may be coated
with iron oxides or clay and such coatings should
be removed by abrasion to expose the oleophilie
surface. Silver is also found in small flaky
form wherein the surfaces are oleophilic unless
coated with material such as iron oxide and clay
which can be removed as by abrasion to make the
surfaces oleophilie.
Those ours are not naturally Leo-
Philip can be made oleophilic by contacting them
with what is termed an activator. These materials
normally act by absorbing on the surface/solution
I 3
1 interface, thereby providing sites for the adsorb-
lion of the collector species. For example,
addition of oxygen to a gold bearing water sup-
pension will increase the oleophilic attraction
of gold.
Minerals can also be made oleophilic
by the addition of agents known as collectors.
These materials provide the surface of the
mineral that is to be recovered with an oily film
that makes the mineral oleophilic. Preferred
collectors are those which add to the mineral
surface to the exclusion of the guying and which
have a hydrocarbon chain or a hydrocarbon ring in
one part of the molecule or at one end of the
molecule and at the other end have a polar element
that is likely to combine with the mineral surface.
For example, oleic acid is a preferred collector.
It has a fairly long hydrocarbon chain and at one
end of the molecule there is the carboxyl radical
which reacts with the mineral surfaces. The same
is true of xanthates.
Other examples of the collectors include
heavy oils, bitumen, fuel oils, long chain fatty
1 acids, long chain amine, polymeric materials
of low molecular weight derived from olefinic
and diolefinic compounds, and the like, and
mixtures thereof.
The oleophilic collector material added
can be ionizing compounds which dissociate into
ions in aqueous mixtures and act by attaching
to the surface of the desired mineral particles
and thereby impart the desired oleophilic pro-
parties. The oleophilic collector may also be
long chain chelates type materials which enter
into a weak chemical bond with the mineral
particles. The added oleophilic collector can
also be non-ionizing compounds or compositions
which are practically insoluble and effect the
desired results by forming a thin film on the
surface of the mineral particles and thus impart
the desired oleophilic character to the resulting
combination.
Preferred ionizing collectors to be
used are those which are asymmetric in structure
and have a non-polar hydrocarbon group attached
to the molecule. The ionizing collectors may be
ho I
1 anionic or cat ionic or mixtures thereof. examples
of these include, among others, organic acids such
as oleic acid, linoleic acid, sodium owlet, sodium
linoleate, long chain sulfates and sulfonates,
xanthates and dithiophosphates, long chain amine,
long chain halides, and the like.
The exact ionic collector to be used in
the process will depend chiefly upon the electron
static attraction between the polar head of the
collector and the charged electrical layer on the
mineral surface, and a few routine tests will
review the most efficient combination of mineral
and collector to be utilized.
The non-ionic collectors which generally
function by coating the surface o-f the mineral
particles may be of any suitable type as long as
the necessary attraction to the mineral particle
is provided. Examples of suitable materials
include, among others, bitumen, heavy oil, diesel
oil, crude oil, kerosene, and the like and mixtures
thereof.
The first step in the process then is
to be sure that the mineral particles have an
29
1 oleophilic surface. This can be accomplished
by selecting mineral particles which by nature
have oleophilic surfaces or can be made so by
the addition of an activator or by the addition
of an activator and a collector or by the
addition of a collector only. The exact prove-
dune to be used will depend upon the mineral
being separated.
The mineral surface should also be
large enough that the oleophilic surface will
be attracted to the oleophilic aperture surface.
If the area is not large enough it can be
increased by grinding or crushing to expose more
of the mineral surface. The crushed ore should
preferably have a particle size Owe 20 mesh or
less and more preferably from 20 mesh to 250 mesh.
The crushing can be accomplished by any conventional
technique, such as jaw crushers, gyrator crushers
or rolls, and if smaller particles are desired they
may be obtained by use of ball mills or similar
equipment.
The mixture containing the mineral
particles having the oleophillc surface is then
I I
1 treated to separate the mineral particles from the
guying. This may be accomplished in a variety of
ways. A preferred technique comprises passing a
mixture of mineral particles having the oleophilic
surface and the guying, and preferably a liquid
carrier such as water, through an oleophilic
aperture wall or barrier or belt which is coated
with an oleophilic material, such as oil, bitumen
or grease, which captures the oleophilic mineral
particles while permitting the hydrophilic guying
particles to pass through the apertures. The oil
oleophilic material is then removed from the
aperture wall and is refined to recover the
mineral and the aperture wall is again covered
with fresh oleophilic material, such as oil, bitumen
or grease to capture more mineral particles in the
subsequent sieving.
Another preferred embodiment comprises
mixing the mixture or mineral particles having
the oleophilic surfaces and the guying with an
aqueous medium containing an oleophilic material
so that the mineral particles become coated with
a thick coating of the said oleophilic material
-14~ C~3~^~
1 and the hydrophilic guying becomes coated with
water. This is preferably accomplished by tumbling
the mineral particles, guying, water and oleophilic
material in a drum for a sufficient period to insure
that the mineral particles are coated with a thick
coating of the oleophilic material. The slurry
that is thus prepared is then passed through the
aperture oleophilic wall wherein the mineral
particles coated with the oleophilic material are
attracted to the oleophilic surface of the aver-
lured wall, and the hydrophilic guying passes
through the apertures. The captured oleophilic
material containing the mineral particles is then
removed from the aperture surface and the process
repeated. There is no need to apply a thick coating
of oleophilic material to the oleophilic aperture
surface in this case and the thick coating is
already on the mineral particles.
Another preferred embodiment comprises
adding an emulsion of oleophilic material, such
as oil or bitumen, and water to the mixture of
mineral particles and guying, and after thorough
mixing, adding an emulsion breaker to the mixture.
-15~ I
1 The emulsion used in this case possesses the Leo-
Philip material as the dispersed phase and the
water as -the continuous phase. When the emulsion
breaker is added to the mixture, oil phase
particles are free to find the oleophilic surfaces
of the mineral particles and adhere thereto. Such
particles are then coated with a thick coating of
the oleophilic material. The resulting slurry is
then passed through the aperture oleophilic wall
wherein the mineral particles coated with the Leo-
Philip material are attracted to the oleophilic
surface of the aperture wall, and the hydrophilic
guying passes through the apertures of the said
wall. The captured oleophilic material containing
the mineral particles is then removed from the
aperture surface and the process is repeated.
Another preferred embodiment involves
a technique for use when the mineral ore itself
contains an oleophilic material. For example,
in many cases tar sands and shale oil particles
contain mineral particles as well as the oleophilic
bitumen or heavy oil. In these cases, the mineral
ore particles which contain the desired mineral
-16- I I
1 particles having oleophilic surfaces, the guying
and the oleophilic material such as bitumen, heavy
oil and the like, are tumbled in a drum in the
presence of water and preferably steam, and the
mineral particles are coated with a thick coating
of the oleophilic material such as bitumen or
heavy oil. When this aqueous slurry is passed
through the aperture oleophilic wall, the mineral
particles coated with the oleophilic material are
captured by the wall and the guying passes through
the apertures. The mineral particles and Leo-
Philip material can then be removed from the wall
and the mineral particles recovered.
The aperture wall having the oleophilic
surfaces to be used in the above-process of the
invention may be of any suitable construction and
arrangement as long as it provides openings for
the gangueparticles to pass through and an Leo-
Philip surface to attract the mineral particles.
Suitable apparatus for -this purpose comprise those
shown in US. 4,236,995 and US. 4,224,138. The
apparatus preferably has the aperture wall in
the form of a screen the cables of which are
-17~ 7
1 coated with or made up of an oleophilic material.
The screen may be immersed, not immersed or partly
immersed in a water bath.
The preferred apparatus to be used as
shown in US. 4,224,138 is illustrated in attached
Figure 1.
The apparatus shown in Figure 1 consists
of an endless aperture conveyor belt having a
top flight 65 and a bottom flight 64 stretched
between two conveyor end rolls 51, 52 in a water
bath 63 having a water level 42. These end rolls
may be crowned to keep the belt running centrally
on the end rolls. Both sides of this belt and
the wall of the apertures are oleophilic. Slurry
from the tumbler is conveyed through conduit 41
into hoppers 43, 44, 45 and 46, the bottom portions
of which can be, but do not have to be submerged
below the surface of water 42 for the purpose of
evenly distributing it at a multiplicity of toga-
lions along the belt. Collector recovery stations
are mounted along the belt on both flights at a
multiplicity of locations 47, 48, 49, 50, 53, 54,
55 and 56.
f~J of 7
1 The separation and collector recovery
at the various locations along the belt is similar.
or this reason it is described here for hopper 44
and recovery stations 49 and 54 which together form
one separation location. The slurry 59 leaves
hopper 44 in the form of a ribbon that is almost
as wide as the belt and with a thickness and
velocity representing a slurry flow rate that can
be conveniently separated by the belt. It falls
through the water 42 and is diluted by it until
it encounters -the top belt flight 65 where water
and the solids in the water phase pass through the
apertures of the belt while the collector is
attracted to the oleophilic surface of the belt.
The top flight 65 of the belt which is in motion
from the right to left carries this slurry along
for some small distance before the separation is
complete. Baffles 57 or other stirring means are
provided to create turbulence in the water above
the belt and to disturb any unseparated slurry
resting on the belt surface.
The collector-mineral composition is
recovered from the belt at location 49. The slurry
2~3~
1 58 that has passed through the apertures of the
top flight settle downward to the bottom belt
flight. Baffles 60, 61, 70 and 71 serve to
contain this slurry so that it will drop onto
the bottom conveyor flight. As the slurry passes
through the bottom flight 64 water and particulate
solids 62 drop to the bottom of the water bath 63
from where they are removed. Substantially all
of the collector-mineral composition that was not
recovered at the top flight is attracted to the
oleophilic surface of the bottom flight 64, which
is in motion from left to right. It is recovered
at location 54. The solids 62 and the water are
removed from the bottom of the water bath 63 at
a rate such that a constant water level 42 is
maintained in the bath. A pump, auger, or some
other mechanical device is used for this purpose.
The aperture oleophilic belt is an
important part of the above-described apparatus.
Construction details of this belt are shown in
Figure 2 and PA. The belt could consist of rota-
lively more rigid members 80 across the belt
that are woven into a mesh belt by the use of
-20- .29'~
1 relatively more flexible members 81 along the
belt. The flexible members 81 consist of cable
constituting two or more strands which enclose
each member 80 across the belt and which are
twisted to maintain the desired spaced relation-
ship between the members 80. This belt can be
made from oleophilic materials and/or can be
covered by an oleophilic abrasion resistant
coating 73. Depending upon their configuration,
i.e., breadth, width or diameter, the size of the
apertures 72 of the belt thus produced, preferably
is within the range of 0.05 to 0.50 inches, and
more preferably within the range of 0.1 to 0.3
inches. Solid particles of conventional ore
slurries pass through the apertures 72 with
increasing difficulty as the size of the apertures
diminishes below these minimum dimensions.
The size of the apertures is influenced
to a large degree by the mean and the maximum
particle size of the solids of the slurry 59, the
concentration of solids in the slurry, the vise
costly of the oleophilic phase, the affinity of
the oleophilic phase for the oleophilic surface
-21- 37
1 of the belt, the size of the oil phase particles,
and the rate of slurry flow passing through the
belt apertures. The size of the apertures along
the belt, further, is influenced by the velocity
of the moving belt surface relative to the
velocity of the slurry passing through the
apertures. The surface speed of the belt will
preferably be between 0.1 and 10.0 feet per
second. For these reasons the physical character-
is tics of the slurry to be separated will determine
to a degree the actual size of the apertures of
the belt and the surface speed of the belt.
The mesh belt can be made from steel
wires, stainless steel wires or from other thin
rods or strands that are strong enough so that
the belt can be used for extended periods in a
commercial plant employing this process. A
coating 73 of vulcanized neoprene or other oil
resistant oleophilic, abrasion resistant and
I strong material can be used to provide a bond
between the members 80 across the belt and the
members 81 along the belt. It is not intended
that this invention be limited to the type of
-22~
1 belt. Other kinds of mesh or perforated belt
that can be used for the process will be apparent
to those skilled in the art. Nylon mesh belts
as is, or covered with an oleophilic coating,
have been used successfully.
Means should be provided for collecting
the adhering collector-mineral combination from
the belt surface and out of the belt apertures.
This is preferably done by the use of rollers as
shown in figure 3. Referring to that figure, the
collector-mineral combination is forced through
apertures 72 with a transfer roller 75 and
collected with a collector roller 76. The collector-
mineral combination on the collector roller can
be scraped therefrom with a doctor blade 77, for
collection in a hopper 78 from where it can be
pumped or conveyed to a central gathering point
for subsequent refining. The collector rollers
normally are driven to provide motion to the belt.
The transfer rollers are driven or left to idle.
It has been found that the rollers can
suitably be formed from a resilient oil resistant
material such as neoprene, urethane, etc. The
-23- en
1 collector roller only works effectively if its
surface is oleophilic but the transfer roller
75 may be either oleophilic or oleophobic. If
the transfer roller is oleophobic, it will push
the oil phase through the apertures 72 without
leaving much residual collector on its own
surface, but it will not do much to aid the recovery
roller in removing the collector out of the belt
apertures 72. Open apertures are needed to
allow the subsequent slurry passage through the
belt in the separation stage. When the belt is
very thin, the recovery roller is able to attract
enough collector from the belt to open the apertures
by itself, a hydrophilic transfer roller can then
be used. In most commercial applications where
the required belt strength necessitates a somewhat
thicker belt, an oleophilic transfer roller 75 will
be preferred. Such a roller pushes the bitumen
through the apertures onto the recovery roller but
subsequently it withdraws some of the collector
out of the apertures, keeping its surface covered
with mounds 79 of collector and aiding the collector
roller 76 in opening up the apertures. An oleophilic
-24~
1 transfer roller 75 may be scraped with a doctor
blade to provide an additional stream of collector-
mineral combination and increase somewhat the rate
of recovery of the said combination.
The mineral can be recovered from the
collector-mineral combination by any suitable
means, such as by solvent extraction, using sol-
vents for the collector such awl for example,
Bunsen, Tulane, acetone, alcohols and the like,
and mixtures thereof, or by the use of thermal
extraction as by heating the mixture to remove
the collector and leave the solid mineral particles
behind. Chemical treatment to break the associa-
lion of the collector with the mineral particles
followed by centrifugation or other separation
techniques may also be utilized.
The desired minerals can thus be
recovered substantially free of the guying and
can be used directly in their intended applique-
lions. Any collector recovered from the separation
step may be recycled and used again in the initial
slurring step of the process.
(keynoted on page 24)
-25~ '7
1 PREFERRED EMBODIMENT
A particularly preferred embodiment
of the invention comprises recovering the minerals
from mixtures containing it and guying wherein
the crushed ore is slurries with water, and an
oleophilic material which may be present in the
ore itself, such as bitumen in tar sands, or may
be added to the slurry.
In this embodiment, the crushed ore
particles, preferably between 20 and 250 mesh in
size, are slurries with water, and the oleophilic
material, preferably in a rotating tumbler, to
effect a thorough mixing of the components and
provide an opportunity for the mineral particles
to come in contact with the oleophilic material.
Steam may be used as well or other materials,
such as suspension agents, stabilizers, and the
like, may be added as desired to assist in the
formation of the slurry. While water is the
desired slurry medium, it is also possible to
utilize solvents or water-solvent mixtures to
form the desired slurry.
The amount of water used in the slurry
-26-
1 may vary over a wide range. The amount o-f water
should be sufficient to give the mixture sufficient
fluidity so there will be proper mixing in the
formation of the slurry and sufficient fluidity
for passage through the aperture surface. In
general, the amount of water employed will vary
from about 0.1 to 5.0 pounds of water per pound
of crushed ore.
The desired temperature to be used
in the formation of the slurry will also vary over
a wide range and is dictated to a degree by con-
gems for economics. Temperatures generally range
from about 85F. to 212F. A slurry with a 50
percent water content by weight, produced at 120 F.
is an acceptable compromise for many of the ore
feed stocks. What is important is that sufficient
water be present to allow all slurry components
to be mixed at the conditioning temperature.
The oleophilic material to be added to
the slurry can be of those described above, as
long as it has the desired oleophilic properties
to attract and attach to the desired mineral
particles and in combination therewith to be attached
-27- I '7
1 to the oleophilic aperture surface.
Oleophilic materials to be used in the
preferred embodiments include the bitumens and
heavy oils already present in some ores. Portico-
laxly preferred oleophilic materials include the
hydrocarbon compositions having a molecular weight
between about 500 and 50,000, and still more
preferably those of the group consisting of
bitumens, heavy oils, crude oils, kerosene, pine
oils, and hydrocarbon polymers derived from olefins
and dolphins.
The oleophilic material to be used may
be a single component or a mixture of two or more
of the above-defined materials. As noted above,
under special cases, such as with tar sands, oil
shales, heavy crude oil deposits, and the like,
the oleop~lilic material may already be included
with the mineral ore particles and additional
material need not be added to the slurry.
The amount of the oleophilic material
to be present in the slurry may vary over a wide
range depending on the concentration of the
desired mineral to be recovered, nature of the
-28~
1 bond -to be employed, temperature and fluidity of
the slurry. In general, the amount of the Leo-
Philip material will vary from about 1 percent to
about 150 percent of the weight of the ore being
treated.
The desired slurry is prepared by intro-
during the water, and oleophilic collector and
crushed mineral ore into a rotating tumbler so as
to effect a thorough mixing of the components and
provide an opportunity for the mineral particles
to come in contact with the oleophilic material.
Equipment other than the rotating -tumbler can
also be used as long as the desired contact is
accomplished. Residence times of about 1 to 30
minutes in the tumbler should be sufficient to
effect the needed contact between the mineral
particles and the oleophilic material.
Oversized particles, such as rocks,
lumps of clay, debris, etc. from the crushed mineral
ore are then removed as shown in US. 4,224,138
before bringing the slurry in contact with the
aperture belt or disc so as to prevent clogging
of the openings with such large particles.
-29- f~.`3~
1 The slurry is then brought into contact
with the oleophilic treated aperture wall as
shown in US. 4,224,13~, and the mineral particles
recovered from the oleophilic layer collected on
the surface of the aperture wall.
The process of the invention can be used
to recover a great variety of different minerals
from mixtures containing the same. The metals may
occur in the ore as free metals or in combination
with other chemical radicals, such as sulfides,
and the like.
Preferred minerals to be recovered by
the process of the invention are those which are
substantially free of oxides on their surfaces,
and contain heavy metals, and particularly those
having molecular weights between 35 and 250.
Compounds containing these metals, and especially
their sulfides, halides and manganates, are
particularly effective in the process of the
invention.
A few metals, such as gold, occur
naturally as free metals but most of the metals
occur in ores where they are bound in crystalline
_30- Jo I
1 structure with other chemical groups or radicals,
such as the sulfide, and the like radicals.
As indicated above, while some minerals
may not be oleophilic per so, they can be made
oleoph fig by use o-f activators or collectors.
examples of ore that can be treated by the process
of the invention include, among others, ores con-
twining titanium such as illuminate, magnetize and
futile; those containing manganese which include
psilomelane, pearliest, manganite, rhodochrosite,
oligonite; those containing chromium, which include
cremate, serpent~nites; those containing nickel,
which include pentlandite, chalcopyrite, pyrrhotite,
garnierite, nepuite; those containing cobalt,
which include lunate, cobaltite, smaltite,
heterogeneity; those containing -tungsten include
shalt, wolframite; those containing molybdenum
include molybdenite, chalcopyrite; those containing
vanadium include paternity, vendetta, vanadinite,
descloizite, titanomagentite, carnotite; those
containing lead and zinc include Golan, sphalerite,
chalcopyrite, pyrites castrate; those containing
mercury include cinnabar; those containing antimony
-31-
1 include stibni-te, quartz; and -those containing
bismuth include bismuthinite; those containing
aluminum include hydragillite, boehmite; those
containing beryllium and lithium include Barlow,
spodumene; those containing magnesium include
carnality, magnesite and dolomite; those con-
twining gold include gold tellurides; those
containing silver include Argentine, prostate,
pyrargirite; those containing platinum group
metals include chromespinellides and hortonolite;
those containing uranium and thorium include
urbanite, vendetta, uraninite, Minnesota; those
containing tantalum and niobium include tantalize,
columbine, pyrochlore-, loparite, microlite; those
containing zirconium and rare earths include bade-
Lotte, Minnesota, xenotime; and other deposits
containing sesame, germanium, thallium, scandium,
cadmium, selenium, tellurium, rubidium, gallium,
indium, hafnium and rhenium.
The process can also be used to remove
minerals such as goat from other solid particles,
such as sand, where the purified solid particles
are the desired product. In many cases, for example,
-32-
1 deposits of construction sand contain contaminate
in components, such as coal, which interfere
with the use of the sand in formation of concrete
as it tends to weaken the structure. In this case,
the process of the invention can be used to remove
the coal from the sand particles and the product
recovered from the aqueous phase is the more desired
material. This illustrates the reverse application
of the process wherein the desired material may be
that remaining in the aqueous phase and the purpose
is to remove the material being attracted to the
oil phase.
The process of the invention can also
be used to advantage in the purification of sludge
ponds at industrial sites where the sludge contains
undesirable oleophilic products, such as toxins, PUB,
and the like, which can be removed by use of the
collectors as in the above-described process of
the invention.
The process may also be used to remove
proteins from mixtures containing proteins and
like substances.
The process may also be used in the prepare-
--33
1 lion of medicines.
While the process of the invention has
been described chiefly in terms of a process for
preparing slurries directly in a conditioning
drum, the process can also be used for treatment
of suspensions or emulsions of oil, tar or hydra-
carbon produced from a heavy oil, tar sand or
oil shale deposits, by steam injection or by no-
lofting or combustion which may contain precious
minerals, by utilizing such compositions directly
in the process as described above.
To illustrate the process of the
invention, the following examples are given. It
should be understood, however, that they are
given only in the way of illustration and in no
way limit the scope of the invention.
EXAMPLE I
This example illustrates the separation
of mica flakes from a mixture of mica and silica
sand.
A mixture made up of 10 pounds of mica
flakes and 90 pounds of silica sand is added to
water slurry made up of 30 pounds of water and
'7
I
1 25 pounds of heavy oil collector and the mixture
tumbled in a rotating tumbler at 100C. After
about 10 minutes of tumbling) the mica becomes
associated with the heavy oil in the oil phase.
The slurry is then introduced into a water bath
which contains an aperture endless belt prepared
from vulcanized neoprene arranged as disclosed
in the above-described preferred embodiment.
Most of the sand drops through the apertures while
most of the heavy oil containing the mica flakes
in the oil phase is collected on the neoprene
belt. The material that passed through the first
flight of the belt passed through the send flight
and any Howe oil remaining in the slurry is
recovered at the second flight on the neoprene
belt. It is found that there is a very high
recovery of the mica flakes in the heavy oil
and little mica is found in the sand tailings.
EXAMPLE II
This example illustrates the recovery
of small amounts of titanium and zirconium from
tailings obtained from the hot water process for
recovering oil from tar sands which process is
ho
low ill co~ercial operatioll. The ore being treated contained traces of zirconium
and titanium. With suckle a process 8 to 15 percent of the bitumen still remains
with the solid ore particles in the tailings.
Tailings from the above process containing 60.0 percent solids, 39.0
percent water and 1.0 percent bitumen was passed through an oleophilic aperture
wall surface as show in United States 49236,995. The bitumen collected on the
screen was removed and treated to recover the zirconium and titanium. The bit-
men collected from these tailings was found to contain more than three times as
much zirconium and titanium percentage by weight as compared with the bitumen
product of the hot water process.
Another important application of the instant invention relates to the
recovery of futile and aunts from the primary and secondary tailings of common-
coal hot water extraction mined oil sands plants. The process used in these oil
sands plants currently in operation in Fort McMurray, Alberta is based upon the
Clark Hot Water Process wherein mined oil sand feed stock is mixed with steam and
water in a conditioning tumbler to produce a slurry. Oversize rock, clay lumps
and tramp are removed from this slurry at a temperature of approximately 185F
and then the slurry is diluted with hot water and is pumped to a primary swooper-
lion vessel when bitumen floats to the top of the vessel and is skimmed off as
a primary froth product. Sand, silt, clay, water and bitumen that will not float
fall to the bottom of the primary separation vessel and are discarded as primary
tailings. A stream of silt, clay and bitumen suspended in water, called the mid-
doings stream, is removed from the middle of the primary separation vessel to
maintain an effective balance in this vessel. The middlings stream is conveyed
to conventional froth flotation vessels where the middlings are aerated to pro-
dupe a secondary bitumen froth product, and a secondary tailings stream that is
discarded. The primary bitumen froth and the secondary bitumen froth are come
- 35 -
'7
brined, mixed Thea a delineate and centrifuged to produce a clean bitumen product
for use as upgrading and refining feed stock and a centrifugal tailings stream.
It is known that the centrifugal tailings contain heavy minerals, in particular
ores of titanium and of zirconium, and several patents have been granted for the
recovery and processing of these minerals, in particular Canadian patents:
861,580 and 879,996 and 927,983 as well as U.S.A. patents 3,656,938 and 3,990,885
and 4,138,467 and 4,150,093.
However, while processing primary and secondary tailings, it has been
discovered that these tailings also contain ores of titanium and zirconium in
abundance. One important finding of pilot plant studies has been that in par-
titular the primary tailings contain approximately 0.3% bitumen which may be
used to collect futile, aunts and zircon from these tailings.
The titanium ores that may be recovered from centrifugal tailings
generally are high in illuminate and low in futile. In contrast, the titanium ores
which may be recovered from primary tailings and from secondary tailings by the
instant invention are high in futile and very low in illuminate. On the world
market futile is worth approximately 20 times as much per ton as illuminate.
In pilot plant tests, two 45 gallon drums of primary tailings were
used as feed stock for the process of the instant invention. This feed stock con-
twined 0.3% bitumen, 75.7% solids and 24.0% water by weight and was conveyed to
a tumbler containing oleophilic free bodies. The actual free bodies used were
1/2 inch diameter spheres of steel, coated with cadmium, spheres of neoprene
mixed with lethargy also 1/2 inch in diameter and 1/4 inch diameter spheres of
polyolefin. About equal amounts of each type of sphere were used in the tumbler.
It has been found that shapes other than spheres may be used as is discussed in
Canadian patent application 333,832. The tumbler was 18 inches in diameter and
18 inches long and was filled with free bodies, leaving only about 20% free-
- 36 -
to
board of the drum volume free from oleophilic bodies to permit effective tub-
lying and mixing of the free bodies with the feed stock which entered the drum con-
tenuously during the test run at approximately 100 pound per hour and which left
the drum from the opposite end at the same rate. The free bodies remained in the
drum throughout the test. While the feed stock mixed in the drum with the free
bodies its dispersed bitumen came or remained in contact with futile, aunts and
zircon in the feed stock and then collected into streamers of bitumen that left
the drum at the exit end along with water suspended solids as a stream. This
stream of bitumen agglomerated tailings next was passed to an aperture Leo-
Philip belt separator such as described in Canadian patent application 333,640.
(Similar separators are described in Canadian patent applications 333,641 and
333,830). In this separator the water suspended solids passed through the
apertures of the oleophilic belt and the bitumen with the contained futile,
aunts and zircon collected on the surface of the oleophilic belt. The belt
revolved continuously and the collected bitumen was subsequently removed from
the belt surface as a bitumen stream that contained a considerable amount of
futile, aunts and zircon as well as other solids such as sand, silt and clay.
The water suspended solids stream analyzed 0.1% bitumen, 69.5% solids and 30.4%
water by weight. The bitumen stream analyzed 38.3% bitumen, 41.7% solids and
20.2% water by weight.
The solids were then removed from the bitumen of the bitumen stream
with a solvent that diluted the bitumen and washed the solids and then the solids
were dried and analyzed. No illuminate was found in the dried solids but futile
content of these solids was approximately 10% along with approximately 0.6% zip-
con, and other materials such as aunts, china clay, and quartz.
A magnetic separation test demonstrated that futile could be removed
readily from most of the other materials present in these dried solids.
Lyle such additional tests were not conducted, there is no reason
that magnetic separation should not be practiced on the solids fraction of the
bitumen product while it is still wetted or suspended in the solvent used for
washing the bitumen from these solids.
Another method for recovering futile from the bitumen product of the
instant invention is to heat the bitumen in an inert atmosphere to vaporize and
crack the bitumen to produce an overhead hydrocarbon vapor that is recovered
subsequently and leave a residue of coke on the solids particles. Then burning
these solids particles with air or oxygen to remove the coke and produce an ash
or solids residue that is relatively carbon free and from which the futile may
then be extracted magnetically either while the solids are a dry powder or while
suspended in water with or without suitable reagents.
Thus the instant invention is of particular advantage for recovering
the more expensive titanium ores, such as futile, from the primary and secondary
tailings of a hot water oil sands extraction process.
In addition, the process may also be used to recover futile, aunts
and zircon from mined oil sands by a similar process. In this case the feed stock
for the agglomerating tumbler, containing the oleophilic free bodies, is a
slurry of mined oil sand and water that has been prepared previously in a condo-
toning tumbler as described above. The process thereafter is similar to the
process used for recovering futile from primary tailings described above. The
same process may also be used with secondary tailings as feed stock to recover
futile from secondary tailings.
Thus the process for recovering futile in the instant invention con-
sits of tumbling the feed stock in a tumbler to permit bitumen and futile to
become intimately mixed with each other in the presence of water and solids.
Free bodies may be used in the drum but do not have to be used to assist bring-
- 38 -
Lo q.31 i'
in the bitumen in contact with the futile in the feed stock. The futile in the
process becomes part of the bitumen fraction and when the thus prepared feed-
stock stream is separated with an aperture oleophilic belt separator the futile
and aunts and zircon are part of the bitumen products stream. Thereafter the
bitumen stream is separated unto its components and futile is extracted as one
of the valuable minerals. Aunts and zircon are additional valuable minerals
that are extracted.
Additional test were conducted to determine the need for a drum con-
twining oleophilic free bodies in the process to collect futile from the tailings
into the bitumen. It was found that without the use of such a drum to treat the
tailings before separation by the aperture oleophilic belt the futile content
in the bitumen products stream was less than when such a drum was used. The
relative amounts were not measured but it appeared that with the drum about I
more futile was produced than without the drum.
From the test work that has been conducted with primary tailings, it
has been concluded that the bitumen particles suspended or contained in the prim-
cry and secondary tailings of a hot water extraction process are loaded with
solids and minerals such as futile and zircon. If this were not so, the bitumen
would float and rise to the top of the extraction vessels of the Hot Water Pro-
cuss. However, the bitumen that finds its way into the primary and secondary
tailings will not float but sinks along with the sand and silt to the bottom of
the vessel. When these tailings are then processed with a method that does not
rely upon bitumen flotation to achieve the separation, such as with an aperture
oleophilic wall separator, the recovered bitumen is high in valuable titanium and
zirconium ores such as futile, aunts and zircon.
During the hot water extraction process not all the futile, aunts and
zircon become associated with the bitumen but some of these minerals are found in
- 39 -
the tailings separate from the bitumen. Therefore, when these tailings are
tumbled in a drum in the presence of oleophilic free bodies, this tumbling helps
to contact these minerals with bitumen in these tailings to cause these minerals
such as futile, aunts and zircon and possibly illuminate to become part of the
bitumen phase which is then recovered subsequently in the separation step.
The above specifications refer to futile, aunts and zircon recovery
from tailings or sludge of a Hot Water Extraction Process plant. However, the
instant invention has application as well in the recovery of these valuable
minerals directly from a prepared slurry of mined oil sand without passing this
slurry first through the primary and/or secondary extraction vessels of the Hot
Water Process. or this aspect of the instant invention, a slurry of mined oil
sand and water and/or steam is prepared which is then passed directly through the
the tumbler with oleophilic free bodies and then through the aperture oleophilic
sieve separation apparatus for recovery of the bitumen and for recovery of the
valuable minerals such as futile, aunts and zircon directly with the bitumen,
and then the separation of these valuable minerals from the bitumen and the sepal
ration of the titanium minerals therefrom by magnetic separation as described
above. Alternately the slurry may be separated without the use of a tumbler con-
twining oleophilic free bodies. In that case the prepared slurry is passed dip
neatly to the aperture oleophilic wall for separation, bitumen recovery and
titanium minerals recovery as described above.
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