4,288,414 Process for chlorinating clays and bauxite

Patent Number/Link:

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

'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

L....l1\----, r----....I. H2 0 f I I i

FeCI

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.

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.

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

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

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

4,288,414

0.06

0.002

0.40

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

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

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

Temp

'c.

650

750

850

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

4,288,414

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

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

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).

* * * * *