U.S. patent application number 10/238297 was filed with the patent office on 2003-08-07 for gel of elemental material or alloy and liquid metal and salt.
This patent application is currently assigned to Kroftt-Brakston International, Inc.. Invention is credited to Anderson, Richard P., Armstrong, Donn R., Borys, Stanley S..
Application Number | 20030145682 10/238297 |
Document ID | / |
Family ID | 27671011 |
Filed Date | 2003-08-07 |
United States Patent
Application |
20030145682 |
Kind Code |
A1 |
Anderson, Richard P. ; et
al. |
August 7, 2003 |
Gel of elemental material or alloy and liquid metal and salt
Abstract
A method of producing a non-metal element or a metal or an alloy
thereof from a halide or mixtures thereof. The halide or mixtures
thereof are contacted with a stream of liquid alkali metal or
alkaline earth metal or mixtures thereof in sufficient quantity to
convert the halide to the non-metal or the metal or alloy and to
maintain the temperature of the reactants at a temperature lower
than the lesser of the boiling point of the alkali or alkaline
earth metal at atmospheric pressure or the sintering temperature of
the produced non-metal or metal or alloy. A continuous method is
disclosed, particularly applicable to titanium.
Inventors: |
Anderson, Richard P.;
(Clarendon Hills, IL) ; Armstrong, Donn R.;
(Lisle, IL) ; Borys, Stanley S.; (Elmhurst,
IL) |
Correspondence
Address: |
Harry M. Levy, Esq.
Emrich & Dithmar
Suite 3000
300 South Wacker Drive
Chicago
IL
60606
US
|
Assignee: |
Kroftt-Brakston International,
Inc.
|
Family ID: |
27671011 |
Appl. No.: |
10/238297 |
Filed: |
September 10, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10238297 |
Sep 10, 2002 |
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10125988 |
Apr 20, 2002 |
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10125988 |
Apr 20, 2002 |
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08691423 |
Aug 2, 1996 |
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5779761 |
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08691423 |
Aug 2, 1996 |
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08283358 |
Aug 1, 1994 |
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09264577 |
Mar 8, 1999 |
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08782816 |
Jan 13, 1997 |
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5958106 |
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08782816 |
Jan 13, 1997 |
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08691423 |
Aug 2, 1996 |
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5779761 |
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08691423 |
Aug 2, 1996 |
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08283358 |
Aug 1, 1994 |
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Current U.S.
Class: |
75/364 ; 75/369;
75/617; 75/619 |
Current CPC
Class: |
C22B 34/1222 20130101;
C22B 5/04 20130101; Y02P 10/20 20151101; C22B 34/1272 20130101;
C22B 34/00 20130101 |
Class at
Publication: |
75/364 ; 75/369;
75/619; 75/617 |
International
Class: |
C22B 034/12 |
Claims
I claim:
1. A method of producing an elemental material of Ti, Al, Sn, Sb,
Be, B, Ga, Mo, Nb, Ta, Zr, V, Ir, Os, Re, U or an alloy thereof
from a halide vapor of the elemental material or mixtures thereof
comprising introducing the halide vapor or mixtures thereof into a
continuum of a liquid alkali metal or a liquid alkaline earth metal
or mixtures thereof to convert the halide vapor to elemental
material or an alloy, said liquid alkali metal or liquid alkaline
earth metal or mixtures thereof being present in an amount in
excess of the stoichiometric amount needed to reduce the halide to
cool the elemental material or alloy to temperatures below the
sintering temperature thereof.
2. The method of claim 1, wherein the liquid alkali metal is Na, K
or mixtures thereof and the liquid alkaline earth metal is Mg, Ca,
Ba or mixtures therefor.
3. The method of claim 2, wherein the halide vapor is supplied at a
pressure sufficient to maintain sonic flow.
4. The method of claim 3, wherein the elemental material is
produced in batches or continuously.
5. A method of continuously producing a non-metal or a metal or an
alloy thereof comprising, providing a supply of halide vapor of the
metal or non-metal or mixtures thereof, providing a supply of a
liquid alkali metal or a liquid alkaline earth metal or mixtures
thereof as a reducing agent, introducing the halide vapor in a
continuum of the liquid alkali metal or alkaline earth metal or
mixtures thereof at a velocity not less than the sonic velocity of
the halide vapor to produce a powder of a non-metal or a metal or
an alloy thereof and a halide of the alkali or alkaline earth metal
by an exothermic reaction, maintaining the temperature of
substantially all of the powder produced below the sintering
temperature thereof and separating the powder from the
reactants.
6. The method of claim 5, wherein the halide vapor is one or more
of TiCl.sub.4, AlCl.sub.3, SnCl.sub.2, VCl.sub.4, NbCl.sub.5,
MoCl.sub.4, GaCl.sub.3, UF.sub.6, ReF.sub.6.
7. The method of claim 6, wherein the halide vapor is TiCl.sub.4,
the liquid alkali or alkaline earth metal is Na, Mg or mixtures
containing either Na or Mg is used, and the temperature of the
liquid reducing agent away from where the halide vapor is
introduced is maintained in the range of from about 200.degree. C.
to about 600.degree. C.
8. The method of claim 7, and further comprising separating the Ti
produced by sequentially distilling the reducing agent leaving Ti
and a salt, passivating the Ti with O.sub.2 and thereafter rinsing
with water to remove the salt.
9. A method of producing Ti powder from a source of TiCl.sub.4
vapor, comprising introducing the TiCl.sub.4 vapor submerged in
liquid Na or Na with an alkaline earth metal to reduce TiCl.sub.4
to a Ti powder and the halide salts of the Na or alkaline earth
metals present and separating the Ti powder from the combination of
Ti powder and unreacted metal and salt.
10. The method of claim 9, wherein substantially all of the Ti
powder has a particle diameter in the range of from about 0.1 to
about 10 microns.
11. The method of claim 9, wherein the TiCl.sub.4 vapor is
introduced into a flowing stream of liquid metal by injection.
12. The method of claim 11, wherein the flowing stream of liquid
metal is present in excess over the stoichiometric quantity needed
to react with the TiCl.sub.4 vapor such that the Ti powder produced
does not sinter.
13. A method of producing an elemental material or an alloy thereof
from a chloride vapor of the elemental material or a mixture of
halide vapors of two or more elemental materials comprising the
steps of introducing the chloride vapor or mixture of chloride
vapors into a reaction zone in the interior of a flowing stream of
a liquid alkali metal, a liquid alkaline earth metal, or any
mixture thereof; intimately mixing the chloride vapor or mixture of
chloride vapors with the flowing metal stream to cause a reduction
reaction therebetween and form the elemental material or alloy
thereof and a salt of the alkali metal, the alkaline earth metal,
or any mixture thereof, and separating the elemental material or
alloy thereof from the salt and unreacted metal
14. The method of claim 13, wherein the temperature of the
elemental material or alloy does not exceed its sintering
temperature.
15. The method of claim 13, wherein the elemental material is one
or more members selected from the group consisting of Ti, Al, Sn,
Sb, Be, B, Ga, Mo, Nb, Ta, Zr, V, Ir, Os, Re, U and alloys
thereof.
16. The method of claim 13, wherein said alkali metal is at least
one member selected from the group consisting of Na, K and Li and
said alkaline earth metal is at least one member selected from the
group consisting of Ca, Mg, Sr and Ba.
17. The method of claim 13, wherein the chloride vapor is mixed
with an inert gas.
18. A method of producing an elemental material of Ti, Al, Sn, Sb,
Be, B, Ga, Mo, Nb, Ta, Zr, V, Ir, Os, Re, U or an alloy thereof
from a halide vapor of the elemental material or mixtures thereof
comprising introducing the halide vapor or mixtures thereof into a
liquid continuum of alkali metal or liquid alkaline earth metal or
mixtures thereof to convert the halide vapor to elemental material
or an alloy wherein the liquid continuum is present in sufficient
quantity to maintain the temperature of substantially all of the
reaction products below the sintering temperature thereof.
19. The method of claim 18, wherein the alkali metal is Na, K or
mixtures thereof and the alkaline earth metal is Mg, Ca, Ba or
mixtures thereof.
20. A method of producing Ti powder from a source of TiCl.sub.4
vapor, comprising introducing the TiCl.sub.4 vapor within a
continuum of a liquid reducing metal principally of Na, Mg or
mixtures thereof to produce Ti powder and a salt of the reducing
metal or metals by a subsurface reaction and separating the Ti
powder from the liquid reducing metal, wherein substantially all of
the Ti powder has a particle diameter in the range of from about
0.1 microns to about 10 microns.
Description
RELATED APPLICATIONS
[0001] This is a continuation-in-part of our previously filed
application Ser. No. 08/782,816, filed Jan. 13, 1997, now U.S. Pat.
No. ______, which was a continuation-in-part of Ser. No.
08/691,423, filed Aug. 2, 1995, now U.S. Pat. No. 5,779,761, which
was a file wrapper continuation of Ser. No. 08/283,358, filed Aug.
1, 1994, now abandoned.
BACKGROUND OF THE INVENTION
[0002] This invention relates to the production of elemental
material from the halides thereof and has particular applicability
to those metals and non-metals for which the reduction of the
halide to the element is exothermic. Particular interest exists for
titanium and the present invention will be described with
particular reference to titanium, but is applicable to other metals
and non-metals such as Al, As, Sb, Sn, Be, B, Ta, Ge, V, Nb, Mo,
Ga, Ir, Os, U and Re, all of which produce significant heat upon
reduction from the halide to the metal. For the purposes of this
application, elemental materials include those metals and
non-metals listed above or in Table 1.
[0003] At present titanium production is by reduction of titanium
tetrachloride, which is made by chlorinating relatively high-grade
titanium dioxide ore. Ores containing rutile can be physically
concentrated to produce a satisfactory chlorination feed material;
other sources of titanium dioxide, such as ilmenite, titaniferous
iron ores and most other titanium source materials, require
chemical beneficiation.
[0004] The reduction of titanium tetrachloride to metal has been
attempted using a number of reducing agents including hydrogen,
carbon, sodium, calcium, aluminum and magnesium. Both the magnesium
and sodium reduction of titanium tetrachloride have proved to be
commercial methods for producing titanium metal. However, current
commercial methods use batch processing which requires significant
material handling with resulting opportunities for contamination
and gives quality variation from batch to batch. The greatest
potential for decreasing production cost is the development of a
continuous reduction process with attendant reduction in material
handling. There is a strong demand for both the development of a
process that enables continuous economical production of titanium
metal and for the production of metal powder suitable for use
without additional processing for application to powder metallurgy
or for vacuum-arc melting to ingot form.
[0005] The Kroll process and the Hunter process are the two present
day methods of producing titanium commercially. In the Kroll
process, titanium tetrachloride is chemically reduced by magnesium
at about 1000.degree. C. The process is conducted in a batch
fashion in a metal retort with an inert atmosphere, either helium
or argon. Magnesium is charged into the vessel and heated to
prepare a molten magnesium bath. Liquid titanium tetrachloride at
room temperature is dispersed dropwise above the molten magnesium
bath. The liquid titanium tetrachloride vaporizes in the gaseous
zone above the molten magnesium bath. A reaction occurs on the
molten magnesium surface to form titanium and magnesium chloride.
The Hunter process is similar to the Kroll process, but uses sodium
instead of magnesium to reduce the titanium tetrachloride to
titanium metal and produces sodium chloride as a by product.
[0006] For both processes, the reaction is uncontrolled and
sporadic and promotes the growth of dendritic titanium metal. The
titanium fuses into a mass that encapsulates some of the molten
magnesium (or sodium) chloride. This fused mass is called titanium
sponge. After cooling of the metal retort, the solidified titanium
sponge metal is broken up, crushed, purified and then dried in a
stream of hot nitrogen. Metal ingots are made by compacting the
sponge, welding pieces into an electrode and then melting it into
an ingot in a high vacuum arc furnace. High purity ingots require
multiple arc melting operations. Powder titanium is usually
produced from the sponge through grinding, shot casting or
centrifugal processes. A common technique is to first react the
titanium with hydrogen to make brittle titanium hydride to
facilitate the grinding process. After formation of the powder
titanium hydride, the particles are dehydrogenated to produce a
usable metal powder product. The processing of the titanium sponge
into a usable form is difficult, labor intensive, and increases the
product cost by a factor of two to three.
[0007] The processes discussed above have several intrinsic
problems that contribute heavily to the high cost of titanium
production. Batch process production is inherently capital and
labor intensive. Titanium sponge requires substantial additional
processing to produce titanium in a usable form; thereby increasing
cost, increasing hazard to workers and exacerbating batch quality
control difficulties. Neither process utilizes the large exothermic
energy reaction, requiring substantial energy input for titanium
production (approximately 6 kW-hr/kg product metal). In addition,
the processes generate significant production wastes that are of
environmental concern.
SUMMARY OF THE INVENTION
[0008] Accordingly, an object of the present invention is to
provide a method and system for producing non-metals or metals or
alloys thereof which is continuous having significant capital and
operating costs advantages over existing batch technologies.
[0009] Another object of the present invention is to provide an
improved batch or semi-batch process for producing non-metals or
metals or alloys thereof where continuous operations are not
warranted by the scale of the production.
[0010] Another object of the present invention is to provide a
method and system for producing metals and non-metals from the
exothermic reduction of the halide while preventing the metal or
non-metal from sintering into large masses or onto the apparatus
used to produce same.
[0011] Stil another object of the invention is to provide a method
and system for producing non-metal or metal from the halides
thereof wherein the process and system recycles the reducing agent
and removes the heat of reaction for use as process heat or for
power generation, thereby substantially reducing the environmental
impact of the process.
[0012] The invention consists of certain novel features and a
combination of parts hereinafter fully described, illustrated in
the accompanying drawings, and particularly pointed out in the
appended claims, it being understood that various changes in the
details may be made without departing from the spirit, or
sacrificing any of the advantages of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For the purpose of facilitating an understanding of the
invention, there is illustrated in the accompanying drawings a
preferred embodiment thereof, from an inspection of which, when
considered in connection with the following descripton, the
invention, its construction and operation, and many of its
advantages should be readily understood and appreciated.
[0014] FIG. 1 is a process flow diagram showing the continuous
process for producing as an example titanium metal from titanium
tetrachloride:
[0015] FIG. 2 is an example of a burner reaction chamber for a
continuous process;
[0016] FIG. 3 is a process diagram of a batch process reaction;
and
[0017] FIG. 4 is a diagram of the apparatus used to produce
titanium.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The process of the invention may be practiced with the use
of any alkali or alkaline earth metal depending upon the metal or
non-metal to be reduced. In some cases, combinations of an alkali
or alkaline earth metals may be used. Moreover, any halide or
combinations of halides may be used with the present invention
although in most circumstances chlorine, being the cheapest and
most readily available, is preferred. Of the alkali or alkaline
earth metals, by way of example, sodium will be chosen not for
purposes of limitation but merely purposes of illustration, because
it is cheapest and preferred, as has chlorine been chosen for the
same purpose.
[0019] Regarding the non-metals or metals to be reduced, it is
possible to reduce a single metal such as titanium or tantalum or
zirconium, selected from the list set forth hereafter. It is also
possible to make alloys of a predetermined composition by providing
mixed metal halides at the beginning of the process in the required
molecular ratio. By way of example, Table 1 sets forth heats of
reaction per gram of liquid sodium for the reduction of a
stoichiometric amount of a vapor of a non-metal or metal halides
applicable to the inventive process.
1 TABLE 1 FEEDSTOCK HEAT kJ/g TiCl.sub.4 10 AlCL.sub.3 9 SnCl.sub.2
4 SbCl.sub.3 14 BeCl.sub.2 10 BCl.sub.3 12 TaCl.sub.5 11 ZrCl.sub.4
9 VCl.sub.4 12 NbCl.sub.5 12 MoCl.sub.4 14 GaCl.sub.3 11 UF.sub.6
10 ReF.sub.6 17
[0020] The process will be illustrated, again for purposes of
illustration and not for limitation, with a single metal titanium
being produced from the tetrachloride.
[0021] A summary process flowsheet is shown in FIG. 1 Sodium and
titanium tetrachloride are combined in a reaction chamber 14 where
titanium tetrachloride vapor from a source thereof in the form of a
boiler 22 is injected within a flowing sodium stream from a
continuously cycling loop thereof including a sodium pump 11. The
sodium stream is replenished by sodium provided by an electrolytic
cell 16. The reduction reaction is highly exothermic, forming
molten reaction products of titanium and sodium chloride. The
molten reaction products are quenched in the bulk sodium stream.
Particle sizes and reaction rates are controlled by metering of the
titanium tetrachloride vapor flowrate (by controlling the supply
pressure), dilution of the titanium tetrachloride vapor with an
inert gas, such as He or Ar, and the sodium flow characteristics
and mixing parameters in the reaction chamber which includes a
nozzle for the titanium tetrachloride and a surrounding conduit for
the liquid sodium. The vapor is intimately mixed with the liquid in
a zone enclosed by the liquid, i.e. a liquid continuum, and the
resultant temperature, significantly affected by the heat of
reaction, is controlled by the quantity of flowing sodium and
maintained below the sintering temperature of the produced metal,
such as for titanium at about 1000.degree. C. Preferably, the
temperature of the sodium away from the location of halide
introduction is maintained in the range of from about 200.degree.
C. to about 600.degree. C. Products leaving the reaction zone are
quenched in the surrounding liquid before contact with the walls of
the reaction chamber and preferably before contact with other
product particles. This precludes sintering and wall erosion.
[0022] The surrounding sodium stream then carries the titanium and
sodium chloride reaction products away from the reaction region.
These reaction products are removed from the bulk sodium stream by
conventional separators 15 such as cyclones, particulate filters,
magnetic separators or vacuum stills.
[0023] Three separate options for separation of the titanium and
the sodium chloride exist. The first option removes the titanium
and sodium chloride products in separate steps. This is
accomplished by maintaining the bulk stream temperature such that
the titanium is solid but the sodium chloride is molten through
control of the ratio of titanium tetrachloride and sodium flowrates
to the reaction chamber 14. For this option, the titanium is
removed first, the bulk stream cooled to solidify the sodium
chloride, then the sodium chloride is removed from separator
12.
[0024] In the second option for reaction product removal, a lower
ratio of titanium tetrachloride to sodium flowrate would be
maintained in the reaction chamber 14 so that the bulk sodium
temperature would remain below the sodium chloride solidification
temperature. For this option, titanium and sodium chloride would be
removed simultaneously using conventional separators. The sodium
chloride and any residual sodium present on the particles would
then be removed in a water-alcohol wash.
[0025] In the third, and preferred option for product removal, the
solid cake of salt, Ti and Na is vacuum distilled to remove the Na.
Thereafter, the Ti particles are passivated by passing a gas
containing some O.sub.2 over the mixture of salt and Ti followed by
a water wash to remove the salt leaving Ti particles with surfaces
of TiO.sub.2, which can be removed by conventional methods.
[0026] Following separation, the sodium chloride is then recycled
to the electrolytic cell 16 to be regenerated. The sodium is
returned to the bulk process stream for introduction to reaction
chamber 14 and the chlorine is used in the ore chlorinator 17. It
is important to note that while both electrolysis of sodium
chloride and subsequent ore chlorination will be performed using
technology well known in the art, such integration and recycle of
the reaction by-product directly into the process is not possible
with the Kroll or Hunter process because of the batch nature of
those processes and the production of titanium sponge as an
intermediate product. In addition, excess process heat is removed
in heat exchanger 10 for co-generation of power. The integration of
these separate processes enabled by the inventive-chemical
manufacturing process has significant benefits with respect to both
improved economy of operation and substantially reduced
environmental impact achieved by recycle of both energy and
chemical waste streams.
[0027] Chlorine from the electrolytic cell 16 is used to chlorinate
titanium ore (rutile, anatase or ilmenite) in the chlorinator 17.
In the chlorination stage, the titanium ore is blended with coke
and chemically converted in the presence of chlorine in a
fluidized-bed or other suitable kiln chlorinator. The titanium
dioxide contained in the raw material reacts to form titanium
tetrachloride, while the oxygen forms carbon dioxide with the coke.
Iron and other impurity metals present in the ore are also
converted during chlorination to their corresponding chlorides. The
titanium chloride is then condensed and purified by means of
distillation in column 18. With current practice, the purified
titanium chloride vapor would be condensed again and sold to
titanium manufacturers; however, in this integrated process, the
titanium tetrachloride vapor stream is used directly in the
manufacturing process via a feed pump 21 and boiler 22.
[0028] After providing process heat for the distillation step in
heat exchangers 19 and 20, the temperature of the bulk process
stream is adjusted to the desired temperature for the reaction
chamber 14 at heat exchanger 10, and then combined with the
regenerated sodium recycle stream, and injected into the reaction
chamber. The recovered heat from heat exchangers 19 and 20 may be
used to vaporize liquid halide from the source thereof to produce
halide vapor to react with the metal or the non-metal. It should be
understood that various pumps, filters, traps, monitors and the
like will be added as needed by those skilled in the art.
[0029] In all aspects, for the process of FIG. 1, it is important
that the titanium that is removed from the separator 15 be at or
below the sintering temperature of titanium in order to preclude
and prevent the solidification of the titanium on the surfaces of
the equipment and the agglomeration of titanium particles into
large masses, which is one of the fundamental difficulties with the
commercial processes used presently. By maintaining the temperature
of the titanium metal below the sintering temperature of titanium
metal, the titanium will not attach to the walls of the equipment
or itself as it occurs with prior art and, therefore, the physical
removal of the same will be obviated. This is an important aspect
of this invention and is obtained by the use of sufficient sodium
metal or diluent gas or both to control the temperature of the
elemental (or alloy) product. In other aspects, FIG. 1, is
illustrative of the types of design parameters which may be used to
produce titanium metal in a continuous process which avoids the
problems with the prior art. Referring now to FIG. 2, there is
disclosed a typical reaction chamber in which a choke flow or
injection nozzle 23, completely submerged in a flowing liquid metal
stream, introduces the halide vapor from a boiler 22 in a
controlled manner into the liquid metal reductant stream 13. The
reaction process is controlled through the use of a choke-flow
(sonic or critical flows) nozzle. A choke-flow nozzle is a vapor
injection nozzle that achieves (sonic velocity of the vapor at the
nozzle throat. That is the velocity of the vapor is equal to the
speed of sound in the vapor medium at the prevailing temperature
and pressure of the vapor at the nozzle throat. When sonic
conditions are achieved, any change in downstream conditions that
causes a pressure change cannot propagate upstream to affect the
discharge. The downstream pressure may then be reduced indefinitely
without increasing or decreasing the discharge. Under choke flow
conditions only the upstream conditions need to be controlled to
control the flow-rate. The minimum upstream pressure required for
choke flow is proportioned to the downstream pressure and termed
the critical pressure ratio. This ratio may be calculated by
standard methods.
[0030] The choke flow nozzle serves two purposes: (1) it isolates
the vapor generator from the liquid metal system, precluding the
possibility of liquid metal backing up in the halide feed system
and causing potentially dangerous contact with the liquid halide
feedstock, and (2) it delivers the vapor at a fixed rate,
independent of temperature and pressure fluctuations in the
reaction zone, allowing easy and absolute control of the reaction
kinetics.
[0031] The liquid metal stream also has multiple functional uses:
(1) it rapidly chills the reaction products, forming product powder
without sintering, (2) it transports the chilled reaction products
to a separator, (3) it serves as a heat transfer medium allowing
useful recovery of the considerable reaction heat, and (4) it feeds
one of the reactants to the reaction zone.
[0032] For instance in FIG. 2, the sodium 13 entering the reaction
chamber is at 200.degree. C. having a flow rate of 38.4 kilograms
per minute. The titanium tetrachloride from the boiler 22 is at 2
atmospheres and at a temperature of 164.degree. C., the flow rate
through the line was 1.1 kg/min. Higher pressures may be used, but
it is important that back flow be prevented, so the minimum
pressure should be above that determined by the critical pressure
ratio for sonic conditions, or about two times the
absolute-pressure of the sodium stream (two atmospheres if the
sodium is at atmospheric pressure) is preferred to ensure that flow
through the reaction chamber nozzle is critical or choked.
[0033] The batch process illustrated in FIG. 3 shows a subsurface
introduction of titanium tetrachloride vapor through an injection
or an injector or a choke flow nozzle 23 submerged in liquid sodium
contained in a reaction vessel 24. The halide vapor from the boiler
22 is injected in a controlled manner where it reacts producing
titanium powder and sodium chloride. The reaction products fall to
the bottom of the tank 25 where they are collected for removal. The
tank walls are cooled via cooling coils 24 and a portion of the
sodium in the tank is pumped out via pump 11 and recycled through a
heat exchanger 10 and line 5 back to the tank to control the
temperature of the sodium in the reaction vessel. Process
temperatures and pressures are similar to the continuous flow case
with bulk sodium temperature of 200.degree. C., titanium
tetrachloride vapor of 164.degree. C., and the feed pressure of the
titanium tetrachloride vapor about twice the pressure in the
reaction vessel.
[0034] In the flow diagrams of FIGS. 1 and 3. sodium make-up is
indicated by the line 13 and this may come from an electrolytic
cell 16 or some other entirely different source of sodium. In other
aspects, FIG. 3 is illustrative of the types of design parameters
which may be used to produce titanium metal in a batch process
which avoids agglomeration problems inherent in the batch process
presently in use commercially.
Brief Description of the Production of Titanium
[0035] FIG. 4 shows a schematic depiction of a loop used to produce
titanium metal powder. The parts of the loop of most importance to
the operation are a large (10 liter) reaction vessel 29 with a
collection funnel 28 at the bottom feeding into a recycle stream.
The recycle stream has a low volume, low head, electromagnetic pump
11 and a flow meter 25.
[0036] A titanium tetrachloride injection system consisted of a
heated transfer line, leading from a heated tank 30 with a large
heat capacity, to a submerged choke flow nozzle 23. The system
could be removed completely from the sodium loop for filling and
cleaning. It should be understood that some commercial grades of Na
have Ca or other alkaline earth metals therein. This has no
substantial affect on the invention.
[0037] Operation
[0038] A typical operating procedure follows:
[0039] 1. Raise temperature of sodium loop to desired point
(200.degree. C).
[0040] 2. Open titanium tetrachloride tank and fill with titanium
tetrachloride.
[0041] 3. Insert the nozzle into the airlock above the ball valve
33.
[0042] 4. Heat titanium tetrachloride tank to desired temperature
(168.degree. C.) as determined by vapor pressure curve (2 atm.) and
the required critical flow pressure
[0043] 5. Start an argon purge through the nozzle.
[0044] 6. Open ball valve 33 and lower the nozzle into sodium.
[0045] 8. Stop the purge and open valve 32 allowing titanium
tetrachloride to flow through the nozzle into the sodium.
[0046] 9. When titanium tetrachloride pressure drops close to the
critical pressure ratio, close the valve 32 and withdraw the nozzle
above valve 33.
[0047] 10. Close valve 33 and let the nozzle cool to room
temperature.
[0048] 11. Remove the titanium tetrachloride delivery system and
clean.
[0049] The injection of titanium tetrachloride was monitored by
measuring the pressure in the titanium tetrachloride system. A
pressure transducer 31 was installed and a continuous measurement
of pressure was recorded on a strip chart.
[0050] A filtration scheme was used to remove products from the
bulk sodium at the end of the test. The recycle stream system was
removed from the sodium loop. In its place, a filter 26 consisting
of two 5 cm diameter screens with 100 .mu.m holes in a housing 20
cm long, was plumbed into a direct line connecting the outset of
the reaction vessel to the sodium receiver tank. All of the sodium
was transferred to the transfer tank 27.
[0051] The reaction product was washed with ethyl alcohol to remove
residual sodium and then passivated with an oxygen containing gas
and washed with water to remove the sodium chloride by-product.
Particle size of the substantially pure titanium ranged between
about 0.1 and about 10 .mu.m with a mean size of about 5.5 .mu.m.
The titanium powder produced in the apparatus was readily separable
from the sodium and sodium chloride by-product.
[0052] The invention has been illustrated by reference to titanium
alone and titanium tetrachloride as a feedstock, in combination
with sodium as the reducing metal. However, it should be understood
that the foregoing was for illustrative purposes only and the
invention clearly pertains to those metals and non-metals in Table
1, which of course include the fluorides of uranium and rhenium and
well as other halides such as bromides. Moreover, sodium while
being the preferred reducing metal because of cost and
availability, is clearly not the only available reductant. Lithium,
potassium as well as magnesium, calcium and other alkaline earth
metals are available and thermodynamically feasible. Moreover,
combinations of alkali metals and alkaline earth metals have been
used, such as Na and Ca. The two most common reducing agents for
the production of Ti are Na and Mg, so mixtures of these two metals
may be used, along with Ca, which is present in some Na as a by
product of the method of producing Na. It is well within the skill
of the art to determine from the thermodynamic Tables which metals
are capable of acting as a reducing agent in the foregoing
reactions, the principal applications of the process being to those
illustrated in Table 1 when the chloride or halide is reduced to
the metal. Moreover, it is well within the skill of the art and it
is contemplated in this invention that alloys can be made by the
process of the subject invention by providing a suitable halide
feed in the molecular ratio of the desired alloy.
[0053] While there has been disclosed what is considered to be the
preferred embodiment of the present invention, it is understood
that various changes in the details may be made without departing
from the spirit, or sacrificing any of the advantages of the
present invention.
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