15 Claims, 1 Drawing Figure
1,605,098 1111926 Dearborn 423/136
1,866,731 7/1932 Starb 423/136
1,875,105 8/1932 Muggleton et al. 423/136
1,891,608 1211932 Scheidt 423/131
3,244,509 4/1966 Nowak et al. 75/29
3,466,169 9/1969 Nowak et al. 423/136
Primary Examiner-Herbert T. Carter
Attorney, Agent, or Firm-Sheridan, Ross, Fields &
Mcintosh
A process for recovering aluminum from clays associated
with coal or bauxite containing iron, siliceous material
and titanium which comprises: (a) chlorinating the
clay or bauxite in an oxidizing atmosphere to selectively
chlorinate and vaporize iron chloride from the remaining
chlorides, (b) chlorinating the residue from step (a)
in a reducing atmosphere or carbon monoxide and vaporizing
the chlorides of aluminum, silicon, titanium,
and the residual iron, (c) separating and recovering the
formed vaporized chlorides by selective condensation.
Silicon tetrachloride may be added to step (b) to suppress
the chlorination of silicon. If the clay contains
alkali or alkaline earth metals, then the residue of step
(b) is treated with sulfuric acid to convert the soluble
chlorides, e.g., gypsum, to sulfates and to regenerate a
chloridizing and binder solution for pelletizing the clay
or bauxite.
United States Patent [19]
Reynolds et ale
[54] PROCESS FOR CHLORINATING CLAYS
AND BAUXITE
[75] Inventors: James E. Reynolds, Golden; Alan R.
Williams, Denver, both of Colo.
[73] Assignee: Public Service Company of New
Mexico, Albuquerque, N. Mex.
[ * ] Notice: The portion of the term of this patent
subsequent to Jun. 26, 1996, has been
disclaimed.
[21] Appl. No.: 50,549
[22] Filed: Jun. 20,1979
Related U.S. Application Data
[63] Continuation-in-part of Ser. No. 873,400, Jan. 30, 1978,
Pat. No. 4,159,310.
[51] Int. CI.3 COIG 23/02; COIF 7/56;
COIG 49/10; COlB 33/08
[52] U.S. Ct ~. 423/79; 423/76;
423/135;423/136;423/149;423/343;423/155;
423/166; 423/481
[58] Field of Search , 423/76-79,
423/135, 136, 149, 343; 75/112
[56] References Cited
U.S. PATENT DOCUMENTS
1,147,832 7/1915 Kugetgen et al. 423/136
1,600,216 9/1926 Dearborn 423/136
[57]
[11]
[45]
ABSTRACT
4,288,414
* Sep. 8, 1981
u.s. Patent Sep. 8, 1981 4,288,414
FIG / FEED
HOPPER,
+ AIR--- ~ATMOS.
PELLETIZ ING .. PELLET PELLET PILE FUE11'" DRYING ~-1 STORAGE
J
'C--._, ,- I i
OXIDATIVE
I--_______..--_J ~
REDUCTIVE
CHLORINATION j CHLORINATION
4 1L __ , I
COfE ~2 I ~ H2~ 04 I I
I I I
CONDENSER I I RESIDUE
220°C I ~ CO GENERATOR I
I I LEACH
I
L....l1\----, r----....I. H2 0 f I I i
FeCI
3
PREHEAT
COMBUSTION WET~ LIQUID/SOLID
PRODUCT CHAMBER SOLIDS SEPARATION
FU~L AtR r TO
DISPOSAL
CONDENSER CONDENSER ... MULTIPLE
-20° C 90° C EFFECT
EVAPORATOR
SiCI 4 IRECYCLE FeCI 3
FeCI3
TiCI 4 * CO a CO2
AICI3 STEAM
FRACTIONAL L- PRESSURE
C12---+
TiCI4 DISTILLATION MAKE
DISTILLATION LIQUID 250°C UP
STE~M ,
TO SALE RECYCLE
t , SiCI4
PEL LETIZING
SiCI4 SiCI4 AICI3 Tn
SOLUTION
STORAGE LIQUID STORAGE SALE
TO SALE
4,288,414
BESTMODE FOR CARRYING OUT THE
INVENTION
The process of the present invention is applicable to
bauxite and clays associated with coals. Clays are generally
fine-grained, earthy material made up of minerals
which are essentially hydrous aluminum silicates. The
specific mineral content of the clay depends upon the
area in which the clay is found. The clays on which the
present process is operable are ones found associated
with coal, for example, parting clays which are found
between seams of coal. Additional examples include top
and bottom contact clays, which are found at the top
and bottom, respectively, of the coal reserve, clays in
the overburden of the coal and clays found in coal refuse,
ie., the washings of coal to remove ash minerals
from the coal.
The invention will now be described with reference
to FIG. 1. First, the clay or bauxite undergoes a pelletizing
step wherein a hydrochloric acid binder solution is
added and it is pelletized into high-density, high
strength pellets in conventional ,equipment such as .an
extrusion type pelletizer. Following pelletizing, the
pellets are dried at about 300· C. in a direct fired dryer,
Dry pellets are inventoried for feed to the shaft chiorin-
DISCLOSURE OF THE INVENTION
A process for recovering aluminum from clays associated
with coal or bauxite containing iron and siliceous
material by the chlorination route which comprises first
separating iron in an oxidizing atmosphere and vaporizing
it, followed by chlorinating the residue containing
the remaining metals including aluminum, silicon, silica,
titanium, alkali and alkaline earth metals, and some iron,
in a reducing atmosphere of carbon monoxide in the
absence of solid carbon to suppress the chlorination of
the siliceous material, vaporizing the chlorides of aluminum,
silicon, titanium and the remaining iron, separating
and recovering the vaporized chlorides by selective
condensation, and treating the final residue, if it contains
.soluble chlorides, with su[furic acid to convert
calCium chloride to disposable gypsum with simultaneous
regeneration of a dilute hydrochloric acid solution
for purposes of prechloridizing the feed and also
providing a suitable binder for pelletizing the feed.
Improvements are forming tlhe feed material into
carbon-free briquettes, and introducing silicon chloride
into the reductive chlorination step to further suppress
the chlorination of siliceous materials contained in the
feed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is flow sheet of the complete process of the
invention.
2
Accordingly, it is a principal object of this invention
to provide a method for recovering aluminum of substantially
high purity from bauxite and clays associated
with coal which contain iron and siliceous material with
5 the aluminum.
It is another object of this invention to provide a
method for suppressing the chlorination of siliceous
material when recovering aluminum as aluminum chloride
from clays and bauxite by chlorination.
It is a further object of this invention to provide a
method for the disposal of alkali and alkaline earth
metal chlorides remaining in the final residue resulting
from the chlorination of clays to recover aluminum as
aluminum chloride.
10
1
TECHNICAL FIELD
PROCESS FOR CHLORINATING CLAYS AND
BAUXITE
BACKGROUND ART
Prior Art Statement
Several processes have been taught for the chlorina- 20
tion of bauxite and aluminum bearing clay. Dearborn in
U.S. Pat. No. 1,605,098 and U.S. Pat. No. 1,600,216
teaches a two stage chlorination of bauxite and aluminum
bearing clays. Both chlorination steps are done in 25
the presence of a reducing agent and chlorine. Muggleton
et al in U.S. Pat. No. 1,875,105 discloses chlorinating
clays in the presence of carbon monoxide and chlorine
at a temperature of 600·-900· C. to chlorinate the
aluminum, iron and titanium. Thereafter, the residue is 30
treated with carbon, chlorine and heat to chlorinate the
silica and aluminum silicates contained in the clay. Staib
in U.S. Pat. No. 1,866,731 discloses treating raw material
containing aluminum imd silicic acid with a carbonaceous
material and equal parts of chlorine and silicon 35
tetrachloride in order to chlorinate the aluminum and
not the silica contained in the material. Nowak et al in
U.S. Pat. No. 3,244,509 utilizes a reductive chlorination
followed by an oxidative chlorination, both performed
at 800·-1200· C., to extract iron from iron oxide bearing 40
materials. Chlorine need not be present for either chlorination
step "and carbon is the preferred reducing agent
for the reductive chlorination step. Nowak in U.S. Pat.
No. 3,466,169 chlorinates ores in a reducing-oxidizing
atmosphere while regulating the amount of added chlo- 45
rine to correspond stoichiometrically to the metal having
the greatest chloride-forming affinity.
With the exception of leaching processes, none of the
prior art teaches a satisfactory process for economically
recovering aluminum from clays associated with coals 50
or from bauxite having the required purity for commercial
sale because of the difficulty of separating the aluminum
from other metals present in these materials,
particularly, iron. Separation through the chlorination
route to recover aluminum as aluminum chloride looks 55
attractive; however, the process must produce an aluminum
chloride of substantial purity. For example, purity
requirements for aluminum chloride feed material to an
Alcoa-type aluminum cell are reported to limit the
Fe203 content of the feed to 0.03 percent. Furthermore, 60
in the chlorination process, the chlorination of unwanted
metals, such as silicon, must be suppressed to
restrict the consumption of chlorine; otherwise, the
process becomes prohibitively expensive.
A further problem involved in recovering the metal 65
values from clays through the chlorination route, is the
disposal of alkali and alkaline earth metal chlorides
remaining in the final residue.
The process of the invention relates to a two stage
chlorination of clays associated with coal and bauxite
for the recovery of aluminum of substantially high pu- 15
rity.
DESCRIPTION
Cross Related Patent Application
This application is a continuation-in-part application
of Ser. No. 873,400 filed Jan. 30, 1978, now U.S. Pat.
No. 4,159,310.
%
TABLE 1
4
tor. Attempts to remove iron from the pellets by chlorination
under reducing or neutral conditions are not
feasible because of cochlorination of excessive amounts
of alumina.
A number of shaft furnace chlorinators used as batch
chlorinators is one method of operation. These chlorinators
are operated with staggered sequence of operation
designed for optimum heat recuperation. For the oxidation
chlorination, the charge is brought up to the proper
temperature with hot, neutral combustion gases from a
coal-fired furnace. A mixture of chlorine and oxygen
gases is then circulated for up to three hours through
the charge to oxidatively chlorinate and volatilize about
90 to 95 percent of iron content. The oxygen is em-
15 ployed in an amount of from about 20 percent to 60
percent and preferably from 30 percent to 50 percent by
volume of the total gas composition. The chlorine is
employed in an amount which is a small stoichiometric
excess of that needed to chlorinate the iron. The oxidative
chlorination is conducted at a temperature of 6500
to 9000 C. and preferably from 7500 to 8000 C. for a time
period sufficient to allow for the chlorination of most of
the iron present. Generally, the time period is from
about 0.5 to about 2 hours. The volatilized ferric chloride
is collected in cooled scraped condenser. The next
step is the reductive chlorination.
Carbon monoxide gas is added to the chlorinator in
an amount of from about 30 to about 70 percent and
preferably from 40 to 60 percent by volume of the total
gas composition. The chlorine is supplied in slight excess
of the stoichiometric amount needed to chlorinate
the aluminum present. The reaction with carbon monoxide
is sufficiently exothermic to be self-heating. Generally,
the temperature of the reductive chlorination
step is from 6000 to 8500 C. and preferably from 6500 to
7500 C. The chlorinator is operated for about one to
three hours to collect a small amount of residual iron
chloride in the first stage condenser and a high purity
aluminum chloride in the second stage condenser. From
about 3 to 20 percent silicon tetrachloride by volume of
the total gas composition may be injected during the
reduction to suppress silica chlorination. A third-stage
condenser collects the chlorides of titanium and silicon.
The onstream chlorinator is then purged with ambient
air to remove residual chlorine and cool the residue.
The purged gas is routed to a chlorinator coming on
line for heat up and to react with the residual chlorine
and silicon chloride. A preferred method of introducing
the silicon chloride is to run the chlorine through the
liquid silicon chloride before it enters the reactor. The
cooled depleted pellets are conveyed to the leach circuit
where water soluble chlorides, if present, are removed
and calcium chloride is precipitated as gypsum
with sulfuric acid. The residue solids are filtered,
washed and sent to the disposal, while the hydrochloric
acid solution is evaporated as required for water balance
control and recycled to the pelletization step for
reuse as a pellet binder and prechloridizer.
In order to illustrate the objectives of the process, the
reported purity requirements for aluminum chloride
feed material to an Alcoa-type aluminum cell are reported
in Table 1.
4,288,414
3
ator or furnace. The clay or bauxite may be ground
before pelletizing; however, this does not affect the
recovery of the metal values. Pelletizing is mandatory
for a shaft reactor. Sequential chlorination techniques
are amenable to the plug-flow nature of the shaft chlo- 5
rinator.
Shaft chlorinations require a high-crush, strong pellet
feed which does not lose strength during chlorination.
Pelletization of clay or bauxite without any binder produces
a weak pellet when sintered at 3000 C. Thus, 10
various binders were tested for the pellets, for example,
sulfuric acid, hydrochloric acid, and sodium chloride.
Bentonite was tested to see if the hot strength of the
pellets could be improved. The latter produces a stronger
pellet if the sintering is done at 10000 C.
Carbon-containing pellets are not satisfactory because
they lose most of their strength during chlorination
while carbon-free pellets appear to maintain their
integrity throughout the chlorination and the residue
pellets are about as strong as feed pellets. Solid carbon 20
is not satisfactory as a reducing agent for the reductive
chlorination. Extrusion or compaction-type pelletizers
are the most satisfactory for low-density feed materials.
Pellets bound with hydrochloric acid are the most satisfactory
although sulfuric acid is a suitable binding 25
agent. As is shown in the flow sheet of FIG. 1, liquid
from the sulfuric acid treatment of the final residue is
recycled to the pelletizing step and this liquid containing
hydrochloric acid and some small amounts of metal
chlorides is a satisfactory binder for the pellets. 30
The pellets are dried with fuel-air or by recuperation
of heat from high temperature gases exiting the oxidation
chlorinator and stored pursuant to chlorination.
As is seen from the flow sheet of FIG. 1, the oxidative
chlorination step comes 'next followed by reductive 35
chlorination. The most effective procedure is to first
remove the iron by selective chlorination in an oxidative
chlorination step followed by volatilization of the
formed ferric chloride and its recovery by condensation.
Up to 98 percent of the iron is volatizied with 40
substantially no chlorination or volatilization of the
other metal values. It is important, of course, that substantially
no aluminum chloride be formed or volatilized
at this stage. As one of the big economic factors
involved with the process is the use of chlorine, it is also 45
important to suppress the chlorination of the other
metal values, particularly siliceous materials, as the
clays can contain over 25 percent silica and bauxite can
contain up to 25 percent silica.
The degree of chlorination in the reductive chlorina- 50
tion step can be greatly reduced by using only carbon
monoxide as a reducing agent rather than a carbonaceous
material such as fuel oil or coke. The injection of
silicon tetrachloride into the reaction gas mixture of
chlorine and carbon is effective in reducing the amount 55
of chlorination of siliceous material contained in bauxite,
refuse coal and clays associated with coal.
The overall chlorination procedure results in chlorination
of alkali and alkaline earth metals present. Suppression
ofthe chlorination of these elements which end 60
up ,in the final residue as chlorides is not emphasized
because a feasible way of disposing of the chlorides in
the residue is known. However, the best reaction condition
for minimizing chlorination of sodium and magnesium
is the absence of carbon during the chlorination. 65 Element
The oxidative chlorination for the selective removal -----A-I-------------9-9.-42-6---
of iron is preferably performed on clays or bauxite pel- SiOz 0.Q25
lets with a hydrochloric acid binder in a shaft chlorina- FeZOJ 0.03
5
4,288,414
6
%
0.06
0.002
0.40
O.OOS
O.OOS
o.oos
TABLE I-continued
Element
CaO
MgO
Na20
Ti02
K20
P20S
which would be an expensive process step. Surprisingly,
thisWas found not to be necessary in this process.
Chlorides ofiron,almnil1.um, silica, and titanium
leave the chlorinator along withunreacted carbon mon-
5 oxide, chlorine and carbon dioxide, and with a small
amount of particulate carryover. The volatilizedchlorides
are' recovered by' fractional· condensation. Offgases
containing volatile chlorid~s are fractionally condensedat
three temperature levels. to produce an iron
10 chloride product; and aluminum clhloride fraction, and a
Optimum chlorination conditions of temperature, liquid mixture of silicon tetrachloride and titanium tetreaction
time, and level of silicon tetrachloride were rachloride. Ideally, FeCb, AICI3, SiCI4 and TiCI4 can
established for the reducing chlorinator. A silicon tetra- be separated according to their relative volatilities in a
chloride concentration in the chlorinator feed gas of 5 series of cooled condensers with high boilers condensto
15 percent by volume of the total gas composition 15 ing first. Scraped condensers in two stages collect the
and a temperature of from 650· to 750· C. for a time crude FeCb and AICI3 fractions:. A third stage conperiod
of 3 hours reduced silica chlorination to less than denser is chilled with a refrigeration unit to condense
IO percent while still sustaining an alumina recovery of SiCI4 and TiCk Staged condensing, whereby the volaover
80 percent. Iron is controlled by selective oxida- tile chlorides are successively removed is the best aptive
chlorination and also by further purification of the 20 proach for selective recovery. Unreacted chlorine, caroff
gas using fractional condensing at two temperature bon monoxide and carbon dioxide are recycled back to
levels. Siliceous material, including silica, potentially a the chlorinator or a carbon monoxide regenerator.
large consumer of chlorine, is almost completely re- Volatile chlorides are condensed in three states. In
jectedby use ofcarbon monoxide only as a reductant, the first stage a 220· C. scraped air condenser is used to
that is, no solid carbonaceous additive, and by the injec- 25 remove most of the ferric chloride. This product may
tion of silicon tetrachloride in the feed gas. The residue be contaminated with cocondensed AICI3, but the final
treatment, which will be outlined below, provides a product is marketable as a coagulant in tertiary sewage
method for dealing with alkali metal and alkaline earth treatment, for example. A second stage condenser opermetals
which may be present with clay. ates at 90· C. with cooling water Ito condense all of the
The carbon monoxide used in the reductive chlorina- 30 AICb meeting the purity requirements for commercial
tion step can be regenerated using a hot coke bed such sale. A third stage condenser operates~t __ 20· C. for
as a Wellman-Galusha carbon monoxide generator. near-complete removal of SiCI4 and TiCI4 from the gas
Oxygen is added to maintain coke bed temperature at stream before recycle. Liquid SiC14 and TiCI4 are con-
950· C. Oxygen is preferable to air to avoid nitrogen densed and then separated by fractorial distillation.
buildup in the recycle gas. Alternatively, the recycled 35 Non-condensables from the third stage condenser
gas can be used as' fuel either in pellet drying or the consist of chlorine, carbon monoxide and carbon dioxchlorinator
preheat zone before going to the carbon ide, and possibly some low-boiling trace chlorides. This
monoxide generator. gas can either be burned for its heating value, if the
Chlorine utilization is related to the rate of gas flow, carbon monoxide content is high enough and if the
or space velocity, with respect to bed volume. The 40 residual chlorine is low, or it can be recycled back to
conditions obtained in the laboratory reactor are not the chlorinator. Carbon monoxide and carbon dioxide
indicative of those which would be determined in a can be recycled to the carbon monoxide generator.
The preheat combustion chamber for preheating the
pilot plant. The reaction rate appears to be proportional shaft reactor for both oxidative chlorination and reducto
bed temperature with a lesser dependence on chlo- 45 tive chlorination is supplied with fuel and air for heatrine-
carbon monoxide ratio in the reaction gas. The ing. As is seen from the flow sheet, excess heat from the
preferred temperature range for the oxidative chlorina- chlorination steps is sent to the pellet drying step. The
tion step is from about 700· C. to 900· C. and from about utilization of all excess heat in the process contributes to
650· C. to about 750· C. for the reductive chlorination the process' economic feasibility.
step.. . . .. 50 The low-iron, AICI3 product may be further purified
It IS seen from the above descnptlOn of the InventIOn by pressure distillation. The chlorides of silicon and
that reductive chlorination using only carbon monox- . titanium can be separated with high purity by fractional
ide, that is, no solid carbonaceous additives such as coal, distillation. The silicon tetrachloride can be recycled to
coke, fuel oil, or pitch results in a large improvement in the chlorinator to act as a chlorinating agent and suprejection
of silica chlorination with no loss in alumina 55 press chlorination of more silica, packaged as a saleable
recovery. Eliminating solid carbonaceous materials as a liquid, or burned with oxygen to produce silica fume
reductant has other advantages, such as, permitting which is a saleable product and thereby regenerating
initial oxidative chlorination of the pellet charge, in- chlorine for recycle. Actually, the combined steps of
creasing the strength of the pellets charged to the chlo- oxidative chlorination of iron and fractional condensing
rinator as there is no loss in pellet strength during the 60 of the AIC!]and FeCI3 in the reducing chlorination may
chlorination as there is when coke, pitch or other car- make an aluminum purification step unnecessary. Silica
boneous material is added. The combination of a quan- chlorination is reduced by the process to a level where
tity of silicon tetrachloride in the chlorination gas, for all of the SiCI4 produced can find a market.
example, six percent combined with carbon monoxide, As stated above, the chlorinations result in substanalmost
completely rejects silica chlorination with only a 65 tially all of the alkali metal and alkaline earth metals
small loss in alumina recovery. Ordinarily, an oxidative being almost completely chlorinated. and these must be
chlorination followed by reductive chlorination would disposed of either by reuse or otherwise. Substantially
necessitate an intermediate addition of coke to the feed, all of the calcium chloride, which may be contained in
4,288,414
TABLE 2
5 Assay
Description Al Si Fe Na K Ca Mg C
Clay No.6 14.7 24.2 1.46 0.111 0.65 1.04
Clay No.8 10.5 25.7 \.26 0.348 \.26 \.24 0.42
Refuse 10.8 20.7 2.61 2.26 1.14 0.12 0.38 4.36
Arkansas
10 Bauxite 23.4 7.23 4.44
7
clay, is converted to gypsum by treatment with sulfuric
acid as shown in the flow sheet. The residue from the
chlorination steps is leached with dilute sulfuric acid
(possible from a S02 scrub-regeneration system on the
power plant stack gas). This precipitates the calcium as
gypsum, leaches out water soluble chlorides (and a
small amount of acid soluble chlorides) to produce an
inert refuse suitable for disposal to existing ash ponds.
The leach solution contains dilute hydrochloric acid,
sulfuric acid and a very small amount of alkali metal
chloride. This solution is concentrated by evaporation
and sent to the pelletizing step, as shown, to pelletize
incoming feed clay. A further result of the treatment is
to prechloridize the alkaline constituents of the clay,
mostly calcium, and thereby reduce chlorine consump- 15
tion by calcium remaining in the pellets. A weak hydrochloric
acid solution is regenerated by the treatment of
8
tained from the washings of an Arizona coal from the
same region.
EXAMPLE I
Oxidative chlorination was performed on a number of
samples of clay and bauxite briquettes bound with hydrogen
chloride binder. The parameters of the chlorination
along with the results are presented in Table 3.
TABLE 3
Feed
Clay 6
Clay 8
Refuse
Oxidizing Chlorinations of Clays
Conditions Sublimate Calcine
Weight Temperature Time CI2 Flow 02 Flow Weight Weight Assay %Volatilization
gm 'C. min cc/min cc/min gm gm Fe AI Si Fe Al Si
30 700 30 150 50 1.99 23.9 0.40 15.5 30.1 78.1 16.1 1.0
30 800 30 150 50 2.70 23.7 0.19 15.7 30.5 89.7 15.6 0.4
30 950 30 ISO 50 3.23 23.2 0.086 12.0 30.8 95.4 37.0 1.6
30 700 30 ISO 50 3.45 23.2 0.096 I\.6 33.9 94.3 14.6 1.1
30 700 30 100 100 \.87 23.6 0.15 12.3 33.2 91.0 7.9 1.4
30 800 30 ISO 50 4.87 22.0 0.D7.5 12.7 34.9 95.7 11.4 3.4
30 800 30 100 100 (Not performed)
30 950 30 ISO 50 6.42 2\.4 0.008 10.2 36.0 99.6 30.8 3.1
30 750 a 100 100 1.2 24.4 0.84 14.02 28.52 73.8 -5.6 -12.1
Analysis of the materials used in the examples set 40
forth herein is presented in Table 2. Clay No. 6 is a
parting clay from the Black Mesa coal mine in Arizona
and Clay No.8 is a bottom contact clay from the Black
Mesa mine. The refuse clay of the examples was ob-
ExA.MPLE 2
A number of tests using the reductive chlorination
procedure described above were preformed on different
samples. Carbon monoxide was used as the sole reducing
agent. It was introduced into the system as a mixture
of chlorine and carbon monoxide. When silicon tetrachloride
was added, it was added to the samples as a
liquid after the chlorine had been bubbled through it.
The parameters of the process and the results are presented
in Table 4. Unless otherwise noted all of the samples
were 30 gram charges.
TABLE 4
EXAMPLES
sulfuric acid with soluble calcium chloride to precipitate
gypsum. The formed hydrochloric acid prechloridizes
the chlorine consuming alkaline earth metals us- 35
ing, indirectly, inexpensive sulfuric acid, thereby reducing
chlorine consumption in the process.
Clay No.8 SiCI4
23 cc/min
Clay 8 SiCI4
50.3 cc/min
Clay 8dehy. No
Clay 8dehy. SiCI4
27 cc/min
(7.7%)
Refuse No
Feed
Clay No.8
Clay No.8
Clay No.8
No
No
No
Temp
'c.
650
750
850
750
750
750
750
750
Condition
Time CI2 Flow CO Flow Product Weights Calcine Assay % Volatilization
hr cc/min cc/min Sublimate Calcine Fe AI Si Fe Al Si
I 220 100 (24.9)1 5.36 35.16 57.6 13.6
2 (19.9) 2.37 38.97 85.0 0.6
3 100 14.8 0.07 \.84 39.17 97.35 9\.4 26.94
I 220 100 (25.2) 2.38 38.41 81.0 25.5
2 (20.5) 1.22 39.89 92.1 6.1
3 1\.0 15.7 0.07 0.67 39.40 97.2 96.7 22.04
I 220 100 (25.4) 5.79 36.12 53.3 19.0
2 (20.8) 4.40 37.01 70.9 0.2
3 10.2 16.2 0.09 2.87 38.59 96.3 85.2 21.22
I 220 100 (25.6) 2.21 39.45 82.0 -31.0
2 (21.3) 1.20 38.37 91.9 -6.0
3 11.8 16.9 0.16 1.02 38.98 92.8 94.5 17.0
I 220 100 (25.9) 4.80 35.9 60.5 -20.6
3 10.5 17.7 0.17 2.05 39.8 92.0 88.5 8.6
I 220 100 (22.3) 11.3 31.9 15.3 2.8
2 (20.5) 9.97 31.5 31.3 11.8
32 4.0 18.9 0.29 9.96 31.3 80.1 36.7 19.2
I 220 100 (22.8) 12.6 33.0 3.5 2.8
32 \.7 20.3 0.34 11.2 32.0 75.0 ·23.6 11.3
I 220 100 (24.7) 7.83 31.9 40.3 -26.9
2 (19.3) 5.77 35.1 65.6 -9.9
3 13.3 14.0 0.20 4.44 36.6 96.4 80.0 17.5
9
4,288,414
10
TABLE 4-continued
Condition
Temp Time C12 Flow CO Flow Product Weights Calcine Assay % Volatilization
Feed SiCI4 "C. hr cc/min cc/min Sublimate Calcine Fe AI Si Fe Al Si
Refuse No 650 I 220 100 (25.0) 6.06 31.3 53.2 -26.0
2 (20.1) 4.33 32.5 73.1 -5.2
3 14.5 15.1 0.12 3.35 36.1 97.7 84.4 12.2
Refuse SiCI4 650 1 220 100 (25.4) 5.55 32.4 56.5 -32.5
22 cc/min 2 (20.8) 3.94 32.3 74.7 -8.2
3 13.7 16.2 0.22 3.76 35.6 95.4 81.2 7.1
Refuse SiC14 650 I 220 100 (26.2) 6.34 35.0 57.4 -33.5
50 cc/min 2 (22.3) 6.20 34.5 64.5 -12.0
3 13.2 16.6 0.23 5.51 36.5 96.6 76.5 11.8
Refuse SiCI4 650 1 220 100 11.1 18.8 0.263 7.48 34.1 95.7 63.9 6.7
36.3 cc/min
Refuse SiCI4 650 2 220 100 13.7 18.8 0.156 4.23 36.2 97.4 79.6 0.9
48.1 cc/min
Bauxite No 750 I 220 100 (21.8) 30.7 13.6 4.7 -36.7
2 (13.6) 28.8 14.7 44.2 7.8
3 29.0 5.4 0.60 22.3 17.9 97.6 82.8 55.5
Bauxite No 650 1 220 100 (21.3) 33.2 10.4 -0.7 -2.1
2 (12.5) 30.8 9.92 45.2 42.8
3 31.2 3.8 0.67 25.4 12.6 98.1 86.3 77.9
Bauxite SiCI 650 1 220 100 (21.9) 29.4 14.5 8.3 -46.4
54.1 cc/min 2 (13.9) 28.8 15.8 43.0 -1.2
3 20.7 5.8 0.65 24.3 17.7 96.4 79.9 5.27
JAmounts in parentheses· were calculated from samples taken during the chlorination process.
2Start with 24 gm reed (charge).
We claim: 25
1. A process for recovering aluminum from material
selected from the group consisting of clays associated
with coal and bauxite wherein the material contains
aluminum, iron and siliceous materials comprising:
(a) chlorinating the material in an oxidizing atmo- 30
sphere containing oxygen in an amount of from
about 20 to about 60 percent by volume of the total
gas composition at a temperature of about 650·
C.-900· C. to selectively vaporize iron as iron
chloride; 35
(b) chlorinating the residue of step (a) in a reducing
atmosphere at a temperature ofabout 600· C.+850·
C. to vaporize the chlorides of aluminum and silicon;
and
(c) separating and recovering the formed chlorides 40
from the vapors by selective condensing.
2. The process of claim 1 wherein the reductive chlorination
of step (b) is performed in the presence of carbon
monoxide as a reducing agent.
3. The process of claim 1 or claim 2 wherein silicon 45
tetrachloride is added to the residue from step (a) in an
amount of from about 3 to about 20 volume percent to
suppress the chlorination of the siliceous materials.
4. The process of claim 3 wherein the silicon tetrachloride
is mixed with chlorine and used as the chlori- 50
nating agent.
5. The process of claim 1 wherein the clay associated
with coal contains alkali or alkaline earth minerals and
wherein the material from step (b) remaining after vaporization
is reacted with sulfuric acid to produce dis- 55
posable gypsum.
6. The process of claim 5 wherein hydrochloric acid
which is formed from the interaction of the sulfuric acid
with the material from step (b) is used to prechloridize
metals contained in the feed clay prior to its selective 60
chlorination.
7. The process of claim 1 wherein chlorine and oxygen
are mixed for the chlorination of step (a).
8. The process of claim 2 wherein the carbon monoxide
is introduced at a volume of about 30 to about 70 65
percent by volume of the total gas composition of step
(b).
9. The process of claim 1 wherein titantium is present
in the bauxite or clay associated with coal and it is
chlorinated in accordance with step (b) and separated
and recovered in accordance with step (c).
10. The process of claim 1 wh&:ein when the clay
associated with coal is subjected to the selective chlorination,
sulfuric acid is added to the residue from the
chlorination to precipitate alkaline earth metal sulfates
and to form hydrochloric acid and wherein the hydrochloric
acid is used to prechloridize metals contained in
the feed clay prior to its selective chlorination.
11. A process for recovering aluminum from material
selected from the group consisting of clays associated
with coal and bauxite wherein the material contains
aluminum, iron and siliceous materials comprising:
(a) chlorinating the material by subjecting it to the
action of chlorine at a temperature of from about
650· C. to 900· C. in an oxidizing atmosphere in the
presence of added oxygen in an amount of from
about 20-60 percent by volume of the total gas
composition to selectively vaporize the iron as iron
chloride;
(b) chlorinating the residue of step (a) by subjecting it
to the action of chlorine at a temperature of from
about 600· C. to 850· C. in a reducing atmosphere
of carbon monoxide in an amount of from about 30
to 70 percent by volume of the total gas composition
to vaporize the. chlorides of aluminum and
silicon; and
(c) separating and recovering the formed chlorides
from the vapors by selective condensing.
12. The process of claim 11 wherein the temperature
of step (a) is from about 750· to 800· C.
13. The process of claim 11 wherein the temperature
of step (b) is from about 650· to 750· C.
14. The process of claim 11 wherein the oxygen of
step (a) is added in an amount of from about 30 to 50
percent by volume of the total gas composition of step
(a) and the carbon monoxide of step (b) is added in an
amount of from about 40 to 60 percent by volume of the
total gas composition of step (b).
15. The process of claim 11 or claim 13 wherein silicon
tetrachloride is added to the residue of step (a) in an
amount·offrom about 5 to 15 percent by volume of the
total gas composition of step (b).
* * * * *