Note: Descriptions are shown in the official language in which they were submitted.
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SEPARAT O~ OE IL~EI~Iq'E l~lD RUTiLE
SPECIFICATION
Titanium in met(lllic form or as a compound is an
important element in the chemical series. For example,
titanium dioxide is utilized in paint pigments, in white
rubbers and plastics, floor coverings, glassware and ceramics,
painting inks and as an opacifying agent in papers. The
other titanium compounds are used in elec-tronics, as fire
~- retardants and waterproofing agents. The metal may be used
as such or in alLoy form as structural material in aircraft,
in jet engines, marine equipment, textile machir.ery, surgical
instruments, orthopedi.c applicances, sporting equipment and
food handling equipment. Ileretofore in recovering the ti-
^1 tanium from titanium bearing sources such as ilmenite, rutile,
etc., the titanium has been subjected to separation steps
which-involve the formation of titanium as a compound in a
~5 valence state of +4, such compounds usually involving titanium
oxide. However, when attempting to separate titanium dioxide
from impurities which are also contained in the ore such as
iron, the hydrolysis of the titanium dioxide at elevated
temperatures from solutions con-taining soluble titanium
species usually results in also obtaining relatively large
amounts of iron impurity with the titanium dioxide product.
In the prior ar-t, various methods have been utilized
to recovcr titanium values from titanium bearing sources.
For example, in U.S. Patent No. 3,236,596 an unroasted il-
menite ore is leached with hydrogen chloride at an elevated
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~:emperat~ . Fol.lo~;.ng this, di.ssolv~d iron is reduced with
iron or other reduc~,ants to preclpitate ferrous ch:Lorlde by sat-
urating the li.quor with hydrogen chloride gas. The hydro-
gel-l chloride is then extracted from -the liquor by a vacuum
distillation and the titanium is recove.~ed by conventional
means. Likewise, U.S. Patent 3,825,419 reduces an ilmenite
ore to produce ferrous oxides. The reduced ore is then
leached for about 4 hours under a moderate pressure thereby
dissolving the iron in the acid along with about 15% of the
titanlum. The iron is recovered as ferric oxide containing
impuriti.es in the spray roaster while the insoluble product
which is primarily titanium diox:ide but which contains all
of the silica present in the original ore is recovered.
U.S. Patent 3,859,077 also discloses a process for recovering
- 15 ti-tanium in which a tltanium tetrahalide is mixed with iron
oxide in slag or a titaniferous ore at an extremely high
temperat~re of about 1000C. to produce volatile impurity
chlorides and titanium dioxide. A similar patent, U.S.
Patent 3,929,962 also reduces a titanium bearing ore at a
high temperature to produce titanium sesquioxide which is
in a forrn whereby it is easier to treat for a titaniurn-iron
separation. Another pri,or art reference, U.S. Patent 3,903,239
teaches a method for recovering titanium in which unroast~d
ilmenite is leached over a period of days at room temperature
to recover about 80~ of the titaniurn. Sulfur dioxide is added
after the leaching to cause a precipitation of the ferrous
chloride after which titanium dioxide is recovered by diluting
and heatirig the solution. While the magnetic susceptibility
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of ilmen.ite hls been known to chancJe by subjecting the il-
menite to a hi.gh temperature roast, I have now found t:hat
by utilizing th~ process of the present invention it is
possible to insure complete conversion of the ilmenite to
a magnetic material which then may be separated from non-
magnetic rutile and recycled for further treatment. By
utilizing the method of the present invention it will be
possible to obtain a conversion of the raw ore to the de-
sired titanium metal values thereby permitting the pro-
duction of said titanium metal values in an economically
feasible manr,er.
This invention relate.s to a process for separating
rutile from ilmenite. More specifically, the invention is
; concerned with the process for recovering greater yields
of titanium from a titanium bearing source such as ilmenite
thus insuring the obtention of said titanium in an economi-
cally feasible manner. By utilizi.ng the improvement herei.n
described in a process for o~taining titanium from a titanium
bearing source, it is possible to obtain greater yields of
the desired product with a separation of magnetic material
from non-magnetic material w.hereby the former may be recycled
. for further separation steps.
It is therefore an object of this invention to pro-
vide an improved process for the production of titanium
metal values.
A further object of this invention is to provide
an improvement in a process for separating a titanium metal
value such as rutile from a titanium bearing source such as
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ilrnenite in a more economical and commercicllly fcasible
manner .
In one aSE~( ct an embodinlent of this invention re-
sides in a process for the separation of rutile and ilmenite
from ilmenite leac h tails which compriscs sub jecting said
leach tails to a flotation trea~ment to separate gangue from
said leach tails, subjecting the separated leach tails to a
roast at an elevated temperature in a hydrous atmosyhere where-
by said ilmenite is rendered magnetic in nature, and separating
the non-magnetic rutile from the magnetic ilmenite.
.
A specif ic embodiment of this invention is found
in a process for the separation of rutile and ilmenite from
ilmenite leach tai ls which comprises sub jecting said leach
tails to a flo~ation treatment to separate gangue frc)m said
leach tails, thereafter subjecting the separated leach tails
to a roast at a- temperature in the range of from about 700
to about 1000C. in a hydrous atmosphere which is afforded
by the presence of steam whereby said ilmenite is rendered
magnetic in nature and thereafter separating the non-magnetic
rutile from the magnetic ilmenite.
The present invention is concerned with a process
for separating ilmenite and rutile from ilmenite leach tails.
By utilizing the present proc ess, it will be possible to ef-
f~ct a more complete separation of ilmenite from rutile and
ultimately obtain a higher yield of the desired titanium
metal values. The method for obtaining the desired titanium
metal value is effected by subjecting a titanium bearing
souxce which also contains other metals including iron,
vanadium, chromium ancl manganese, such as an ilmenite ore,
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to a reductive roast at an elevated temperature in the range
of from 650 to 1000C., said reductive roast being effectedin
the presence of a reductant such as hydrogen, carbon monoxide,
combination of carbon monoxide and hydrogen, or any other
suitable reductant. In the preferred embodiment the reduc-
tive roast is effected on a metal bearing source such as an
ore which has been c~ushed to a particle size less than 100
mesh for a period of time which may range from 0 5 up to 2
hours. One particular reducing atmosphere which may be used
to accomplish the purpose of the roast comprises a mixture
of about 50~ carbon monoxide and 50% hydrogen with an excess
of the reductant being utillzed in order to completely re-
duce the iron which is present in the system to the metal.
Following the reductive roast of the metal bearing source,
the source is then su~jected to an aqueous hydrogen chloride
leach which is also effected at elevated temperatures usually
in the range of from 85 to 105C. for a period of time
ranging from 0.25 up to 1 hour in duration. The aqueous
hydrogen chloride solution which may also be characterized
as hydrochloric acid will contain from 20% up to 37% hydro-
J gen chloride. Upon completion of the leach step the solu-
bilized titanium metal values will be separated from the solid
tails which will comprise unreacted ilmenite, some rutile and
gangue which comprises silica, mica and quartz. v
The solid tails which remain are suspended in a
water slurry and an appropriate flotation collector reagent
is added such as tall oil or oleic acid. The pH of the
slurry is adjusted to a range of from 6 to ~. The adjustment
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of ~h~- p~l is accomplishe~l by the addition of an acid or base,
the usLIal additive bein~3 a base such as lime. The slurry
is agit.lted viyorously or approxiMatel~ 5 minutes, at which
tir;le air bubbles are introduced into the siurry, resulting in
; the ilmenite and ru-tile floating on or near the surface of the
slurry while the gangue will sink and collect at the bottom of
the vessel. Thereafter the suspended ilmenite ~nd rutile may
be filtered or skimmed off with the froth and recovered.
Following recovery of the mixture of ilmenite and
rutile, the solids are then subjected to a roast. The roas-t
is effec-ted at an elevated temperature in the range of from
700 to 1000C. and preferably at a range of from 750 to
900C. To insure a conversion of the ilmenite to a magnetic
material durin(3 the roasting, the a~oresaid roast is effected
in a hydrous atmosphere, said hydrous conditions being nec-
essary to convert the;ilmenite to a magnetic material rather
than remaining non-magnetic in nature. The hydrous atmosphere
during the roast is effected by the presence of water which
may be in the form of steam or vapor. The ilmenite and ru-
tile are roasted in this hydrous atmosphere for a period of
tirne which may range from 0.5 up to 2 hours in duration,
the amount of time required being that which is sufficent
to convert all of the ilmenite to a magnetic material.
Upon completion of the desired roasting period the
magnetic ilmenite may be separated from the non-magnetic ru-
tile by any conventional means such as applying a magnetic
force to the miY~ture whereby the ilmenite is attracted to said
magnetic force while the non-magnetic rutile remains in position.
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Thereaf~er the ilme~ite which has been separate~ from the
rutile may be recovered and recycled to form a port:ion of
the feedstock which is subjected to the aforesaid steps of
reductive roasting and leaching, while -the rutile may be
recovered and processed in any conventional manner to ob-
tain the desired titanium values.
While the aforesaid description of the process is
indicative of a batch type operation, it is also contemplated
within the scope of this invention that it is possible to
; - 10 effect the process using a continuaus method oE operation ~-
in which the charge stock comprising crushed ore is con-
tinuously fed to a reducing roast zone wherein the charge is
subjected to a reductive roast utilizing a reductant of the
type hereinbefore set for-ch which is also continuously charged
to this zone. After passage through the zone for a prede-
` termined period of time the reduced charge stock is con-
tinuously withdrawn and passed to a leaching æone wherein
it is subjected to leach treatment with a hydrogen chloride
source such as hydrochloric acid. The leaching zone is
maintained at an elevated temperature and after passage
through this zone the leach liquor and tails are continu-
ously withdrawn and passed to a separation zone wherein the
leach liquor con-taining dissolved metal chlorides is continu-
ously withdrawn after separation from the leach tails. The
leach tails comprising undissolved or unreacted ilmenite,
rutile and gangue is continuously charged to a flotation
zone wherein a flotation slurry is effected at a pH in the
range of from 6 to 8, said pH being maintained by the intro-
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duction of an acid or base in an amount necessary to afford
the desired range. The ilmenite and rutile are continuously
withdra~n from this zone ~ decan-tation, filtration or other
means known in the art and passed to a roast zone wherein
the solids are subjected to a roast at a temperature in the
range of from 700 to 1000C. in a hydrous atmosphere, said
atmosphere being afforded by the continuous introduction of
water in the form of vapor or steam to the roast zone. Ater
passage through the roast zone the solids are passed to a
separation zone wherein they are subjected to the action of
a magnetic force, the magne-tic nature of ilmenite material
causing a separation from the non-magnetic rutil~. After
separation of the non-maynetic rutile from the magnetized
ilmenite has been effected, the latter may be recovered
lS by any conventional means and recycled to the reductive
roast zone to form a por-tionof the feedstock while the ru-
tile is collected and subjected to any convention~ means of
treatment whereby the desired titanium values may be recovered.
It is to be unders-tood that the leached liquor which con-
tained the dissolved metal chlorides after having been
separated from leached tails may be treated to precipitate
titanium dioxide which is thereafter recovered and passed
to storage.
The following examples are given for purpo$es of
illustrating the process of this invention. However, it is
to be understood that said examples are given merely for
purposes of illustration andthat the present process is not
necessarily limited thereto.
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EX~MPLE 1
A sample of ilmenite rnay be crushed to -100 mesh
and therea~ter heatecl to a temperature of 750C. under nitrogen
in a rotating quartz furnace tube. Following this hydrogen
and carbon monoxide gas may be passed through the tube at a
rate of 640 cc/min. for a period of 1 hour while maintaining
-~ the temperature of the tube at about 750C. At the end of
the 1 hour period the tube and sample contained therein may
be cooled under nitrogen to room temperature and the reduced
ilmenite ore may be mixed with concentrated hydrochloric acid
and heated to a temperature of 100C. The solid ilmenite ore
may be leached for a period of 0.25 hours under reflux and
filtered.
The leached solids were suspended in a water slurr,v
containing oleic acid. The ph of the slurr,v was adjusted to
about 7 by the addition of lime. The slurry was then agitated
for five minutes, at which time air bubbles were introduced,
- causing the ilmenite and rutile to float on the surface. The
ilmenite and rutile were then skimmed off and recovered.
The ilmenite and rutile solids were then roasted for a
period of 1 hour at a temperature of 900C in a fluid-bed
reactor using steam as the fluidizing gas. After cooling,
it was found that the ilmenite in the sample was magnetic in
nature and was completely attracted to a magnet.
In contradistinction to this, when a second sample
of the ore was roasted for a period of 1 hour at a temperature
of 900C. using dry air as a fluidizing gas, the sample after
Gooling exhibited no reactivity to the magnet.
EXAMPLE II
In this example a sample of ilmenite ore from Norway
was treated in a manner similar to that set forth in Example
I above and roasted in a fluid-bed reactor for a period of 2
1 0 -
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66
hours at a temperature of 900C. using steam as the fluidizing
gas. At the encl of the 2 hour pcriod the sample was cooled
and the ilmenite was follnd to be completely attracted to
; a magnet.
A second sample of the ilmenite ore from Norway when
roasted at 750C. in a fluid-bed reactor using steam as the
fluidizing gas also exhibited a high reactivity to a magnet
upon cooling.
Conversely, if the samples of Norwegian ilmenite
ore are treated in an oxidizing atmosphere which is anhydrous
in nature, the ore, after treatment, will not exhibit any
magnetic activity.
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