CA1162027A - Improved method for the carbochlorination of alumina in a molten salt bath - Google Patents

Abstract

PRECISION OF DISCLOSURE:

Carbochlorination process for chloro-chlorination anhydrous aluminum rure consisting in bringing into contact a source of alumina consisting of agglomerates and an agent of chlorination in the presence of a reducing agent in a bath molten salts containing at least one alkali halide and / or alkaline earth, which is characterized in that it constitutes a filling of the molten salt bath by means of said agglomerates rats, in order to cause intimate contact between gas, liquid or solid phases. The application of this process allows hourly production of aluminum chloride greatly improved, without the need to resort complex and costly technological solutions.

Description

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An improved method for chloride formatiDn anhydrous aluminum by carbochlorination of alumina in molten salts.

5 It has long been known to produce alum chloride, inium by carbochlorination of an aluminous ore or by carbochlorination alumina obtained by attacking an ore containing it. The importance economic tance of obtaining industrial aluminum chloride minimum for catalytic applications or for electro-10 lytic al ~ lminium, led those skilled in the art to perform in-depth research in this area. This is how many processes have been described in the specialized literature, which relate processes for the production of anhydrous aluminum chloride by carbon chlorination of alumina in the vortex phase, or in 15 molten salts.

The first type of process, illustrated by the French patent 1,481,390 describes the carbohydrating of alumina with the production of chloride anhydrous aluminum. According to this process, the ch: anhydrous aluminum loride 20 is obtained by reaction with alumina in a vortex layer of low ash chlorine and carbon, t ~ tem ~ temperatures between 450 C and 600 ~ C using the exothermic character of the reaction:
`A1203 + 3/2 C + 3 C12 ~ A12C16 + 3/2 C02 + ~ millithermia The solid reagents can be introduced separately or as a mixture.
One can thus produce, in continuous mode, aluminum chloride anhydrous which is entrained in the gaseous state with the exhaust gases `to be condensed in a zone cooled to this e ~ fet.

30 Although it is thus possible to obtain, in a simple manner chloride anhydrous alumiriium in a single stage by reaction chlorine and ~
coal with swirling alumina, this process requires that we use a coal ~ with low ash content ~ this one should not be higher ~ ~ ù ~ e plus, po ~ r ensure a cnurs c ~ rrect . . :
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r of the above reaction, the ~ ranulometries of alumina and char-implemented, must be similar and preferably identical ticks, so that there is no demixing of the bed during carbochlorination.
In addition, the practice of such a process exi ~ e the use of an alumina high specific surface, in particular alumina ~, for be of sufficient reactivity. ~ lais, this particular alumina high specific surface, is more highly hydrated than an alumina a, for example, and, as a result, is behind a significant loss chlorine by formation of hydrochloric acid.

ETlfin, co ~ me the alumina used is ~ generally of Bayer origin, it is accompanied, as sodium impurity in a form oxidized, which combines, during the carbochlorination reaction in bed fluidized, forming sodium chloroaluminate, a fraction of which is driven p ~ r vapor pressure ~ ur gaseous effluents, while that the other fraction remaining in the reactor, causes a ~ luti-materiala ~ Y nations forming the fluidized bed and a demixing of said bed.

The second type of process, which concerns the carbochlorination of alumina in molten salt baths, illustrated by the French patent ~ nais.
2,334,625, consists in bringing into contact, in a bath of molten salts formed from at least one alkali and / or alkaline earth metal chloride - and aluminum chloride, alumina with a source of chlorine in presence of a non ~ nitrogenous reducing ent, such as carbon, anhydrous aluminum chloride being collected at the outlet of the bath under a gaseous form.
Cependc ~ nt, this type of process, well ~ ue producing aluminum chloride minium anhvdre of sufficient purity for electrolytic production aluminum tick, is not effective enough to have a hourly production yield of aluminum chloride which can satisfy fullemcn ~ the skilled person. Indeed, the al ~ ine is in-troduitc in ~ the salt bath ~ on (read in its most usual form, that is, in the form of a fine white powder, as well as : ''; . . -. ,. : ,, -:

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'' I'a ~ ent reducer such as carbon, reduced to a dimension s ~ nilaire The chlorine intended for the carbochlorination of alumina is then insufficient.
flé continuously in the bath of molten salts in proportion70n stoechiomé
stick, in which were immersed ~ gas diffusers ~ x, of known types, such as, for example, quartz rings, these diffusers causing the formation of a very ~ rand number of gas bubbles of very small dimensions which come into contact with the elementary rains of alumina and carbon suspended in the bath subjected to agitation. rlal ~ re the presence of these diffusers for the ga- phase zeuse, only a fraction of the chlorine introduced into the bath to will react with alumina and carbon, while the other fraction would be evacuated from the carbochlorination chamber with chlorurc from a-luminiu ~ vaporized, if expensive solutions were not used, such as, for example, that which would consist of practicing an a ~ i-tation -forced in a high temperature environment and particularly a ~ ressif, while respecting sealing conditions dif ~ icile-ment compatiblcs av ~ c lcs im ~ ratir5 unc pro ~ ction in ~ us- ~ ricllo:
security, reliability, maintenance.
Apart from the above-mentioned difficulties, this lack of intimate contact be solid, liquid and gaseous materials, would be at ori ~ ine hourly production of aluminum chloride ~ hydrous per meter relatively small bath cube, despite all attempts until this day.

Aware of the interest that a man of art can offer a process for obtaining aluminum chloride by carbochlorination of alumina in molten salt baths, but also aware of the drawbacks attached to ~ x processes previously described in the literature specialist, the plaintiff, continuing his research, found and developed an improved process for the carbochlorination of alumina, whose hourly production is very improved, without it being necessary Be sure to have recce rs to complex and expensive solutions.
~ -According to the invention, the process for producing aluminum chloride by carbochlorination, which consists in putting a source in contact ~;
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'' alumina made up of agglomerates made by agglutination and a chlorination agent in the presence of ur, reducing agent ~ in a bath molten salts containing at least one alkaline and / or alkaline halide earthy, characterized by the fact that the lining of said bath is formed by said agglomerates with the aim of ensuring a very intimate between the gaseous, liquid and solid phases present during of the reaction.

The bath of molten salts, the compositions of which have been very widely disclosed by specialist literature, generally consists of a rn ~ mixture of at least one alkali and / or alkaline earth halide with aluminum chloride. Among the halides which can be introduced, it has been noted as desirable to reuse metal chlorides alkaline and / or alkaline earth, preferably lithium chlorides, 15 of sodiuln, (.le potassillln, ains: i clue chlorides of calciw ~, ck ~ barium ~;
and key magn ~ si.urn.

The molten salt bath comprencl é ~ alement in its fon ~ ue mass from 2 to 60 O but preferably between 10 "0 and 50 O by molar mass of chloride 20 anhydrous alurninium. .

The temperature of the molten salt bath intended for carbochlorination according to the invention, lies between its melting point and its point of boiling in the conditions of use The plaintiff has ~:
25 found that the temperature range practiced was between.
u C and 900U C, but the preferred temperature zone is . was between 600a C and aODC.

The chlorinated agent used in the context of the invention is generally `30 chlorine gas. However, other chlorine sources may be also used such as, for example, CCl ~, C2Cl ~, etc. ~ .. or their mixtures. The chlorinated agent is introduced into the reaction medium. -in an amount at least stoech.i.om ~ trique compared to the alumina - carboch.l.orer .introcll.lito dan ~ le bal.r ~
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The reducing agent used in the framework of the carbon chlorine can:
be in a gaseous or ioli.de form and at least a quanti.té

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stoichiometric compared to 1 alumina ~ carbochlorer introduced in the bath.

When the reducing agent is in gaseous form, it is made up - 5 with carbon monoxide) or dioxalene (C2039. In this case, the c ~ anhydrous aluminum loride obtained is particularly pure, and can 8be used in the field of catalysis for example, because it is well known that aluminum chloride obtained by carbochlorination alumina under a high temperature, by the simultaneous action of chlorine gas and a reducing agent such as carbon ~ coke, char-wood voucher ...) contains a certain amount of organic compounds polychlorinated such as hexachlorobenzene ~ hexachloroethane, decachlorobiphenyl, etc ..., which is formed for ~ ent during the reaction of car-alumina bochlorination, and which can reach a weight content important, ranging up to 1% at 5 ~ -de content of AlC13. Such organic compounds can be of great discomfort in the groin of catalysis of gold ~ anic syntheses and are all the more genc ~ nts that they have physical properties relatively close to those of aluminum chloride ~ lydre in particular, which ~ nd it is hexachlorobenzene and they are very difficult to separate aluminum chloride by means known to those skilled in the art, such as as for example sublimation.
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When the reducing agent is in a solid form, this a ~ ent is pre-preferentially carbon, but can be optionally chosen by mi from other well known reducers. Qucmd the reducer is carbon, it comes from the usual well-known sources of art, that is to say coals, petroleum and their derivatives. This Tee agent conductor is implemented after possibly having undergone a treatment ment of purification as well as a treatment of broya ~ e, such ma-denial that it appears as small solid particles ble`s dimensions, for example between ~ 0.2 and 200 mm but, of preferably between 0.5 and 8 mm.

As it has already been expressed, the source of alumina therefore disincentives the bocllloration is introduced into the molten salt bath, under a elaborate form of a ~ glomerates made by ag ~ lutination.

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Indeed, during the many experiences that led him to the object of the invention, the Applicant has found that the introduction, into the bath of molten salts, of alumina in its most usual form-le, i.e. in the form of a fine white powder, required the use of gas diffusers of known type immersed in said bath, such as, for example, quartz rings, for the gas mixture chlorination continuously blown into the carbochlorination medium, these diffusers causing the formation of a very large number of bul-very small ga7euses which come into contact with elementary alumina and carbon grains suspended in the bath subjected to agitation.

In the absence of complex and / or expensive technical solutions, such-them that, for example, forced agitation or increased con-sequent of the height of the bath, the only presence of the diffusers zeux is insufficient to ensure acceptable hourly production aluminum chloride.
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The lack of intimate contact between the insuffi cient gas reaction, for example, chlorine or chlorine and carbon monoxide, the liquid reaction of fonclus salts and ~ with solid fraction constituted alumina or a mixture of alumina and carbon, led the request I find that the reaction yield between alumina, the reducing agent and the chlorinating agent, is very greatly improved ; 25 d, even in the absence of the aforementioned gas diffusers, when the source alumina is introduced into the molten salt bath in the form made up of agglomerations made by agglutination.
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In this case, the alumina agglomerates, constituting the p ~ arnissage clu Fonclus salt bath diffusing the gaseous agents; introduced, are put implemented so as to form a lining containing inté ~ ralement the molten salt bath, that is to say that the total volume occupied by the alumina agglomerates and the ~ wavy salt bath is equal to the volume `
apparently occupied by ag ~ lomers alone for the same section of reactcur.
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But, it is also] 1 ~ possiblc to obtain dcs prod-lctiolls ~ or ~ ires .
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3L ~ 6 Z i ~ 2 Lf equivalent of anhydrous aluminum chloride even when the lining age of the molten salt bath constituted by the agglomerates, contains only a fraction of said bath, and no longer its entirety, ~ -to say that, for the same section of carbochlorination reactor, the Applicant has found that the total volume occu ~ ed by a ~ glomé-alumina rats and the molten salt bath may be greater than your apparent lume occupied by agglomerates alone, but at most two times the apparent volume occupied by these agglomerates alone, and is, of preferably, at most 1.5 times this same apparent volume.
Alumina, intended to be agglomerated for carbochlorination according to the invention is generally hydrar ~ illite or boeh-mite, al ~ ines hydratees arising from the alkaline attack of the ba-xite. But ~ it can also come from the decomposition of chlo-aluminum rure hexahydrate, sulfates, sulfites or nitrates aluminum hydrates, resulting from the acid attack of minerals silico-aluminous. do not even, the various aluminas corresponding to phase transformations, such as amorphous or crystalline alumina ne, for example in the form alpha, gamma, delta, theta, iota, eta, chi and kcappR, can be agglomerated and successfully undergo the carbochlorination according to the invention. Besides these diverse origins, the Applicant has also found that the surface speci: Eique, that pr ~ -feel these various forms of alunine, has no harmful influence on the carbochlorination of alumina a ~ glomerated ~ In other words, carbochlorination of alumina agglomerates offering a specific surface of 2 m2 / g is carried out with as good results as those obtained required during the carbochlorination of alumina agglomerates ~ 160 m2 / g.
Carbochlorination therefore offers practically the same efficiency, not only ~ ent with various types of alumina, but also with a mixture of these various types of aluminas.

The a ~ alumina glomerates, intended to be subjected ~ carbochlora-tion according to the invention, are generally prepared by the methods known to those skilled in the art.
Thus, when is practiced ~ the agglomeration of an alumina amo ~ he, the method consists, as described in the French patent ~ ais n 1,190,094, to ~, I.

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a ~ glomerate with water a dry powder of an intimate mixture of tri-aluminum hydrate e ~ of sodium aluminate, or else to use the melan ~ e obtained by drying an unwashed trih-ydra-te cake, at a temperature in ~ re 80C and 150C and to grind said ~ cake after drying. Dry powder of melan ~ e sodium alumina-aluminate is introduced into a ~ ranulator, at the same time as a quantity adequate water. The granules obtained have a diameter included, for -example, between 4 and 6 mm, and are subjected to heat treatment.
But when es ~ practiced a ~ glomeration of an alumina from decomposition of loride! aluminum hexahydrate ~, sul- ~ ates, nitrates, hydrated aluminum sulfites, this agglomeration can be carried out for example according to the method described in the patent French vet n 2.359.094, which consists in compacting a 'product intermediate "from the incomplete decomposition of one of the salts of hydrated aluminum, to ~ roll up the compacted product and treat it thermally.

However, the Applicant has found that the a ~ lomérats pretan-t the ~ ieux carbochlorination bath of molten salts by providing a high hourly yield of aluminum chloride, are those of -forms compact substantially spherical or cylindrical, obtained according to the procécté described in the French patent ~ ais n 1,077,163. This process con-siste, first, ~ dehydrate an alumina hydrate ~ e, at a temperature between 150C and 600C, under conditions such as the fear of water is eliminated as and when ~ its die ~ a ~ ement, then ~ grind the dehydrated product in order to obtain the F ~ r ~ nulometry nlus `favorable to the agFIomeration mode plans, then, to train granules by pressaFe, spinning or ~ ranulation with a bezel, in use as a water binder in which hydrofluoric acid and / or 30 or one or more metal salts can be optionally solution, ~ harden ag ~ lomers by keeping them in atmosphere humid, to raise the temperature of the medium to accelerate the hardening without exceeding the temperature of 150C, finally, subject the a ~ glomerates thus obtained to a heat treatment, depending on the use for which they are intended.
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- ~ ais, the plaintiff noted with interest that it was possible .,. . :.
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_9_ to feed the bath of molten salts by means of ag ~ mixed lomers for-més of a mixture of alu ~ ine and the reducing agent, such as carbo-ne or its derivatives.

Finally, alumina can be introduced into the bath of molten salts under the form, also developed, of alumina bars produced according to known techniques, from alumina agglomerates or ag ~ lomers mixed carbon and alumina, lics, for example, using a coking agent ~ or by means of scls entering the co ~ position of the bath of carbochlorination, said bars having the property of being cl ~ sagré-ger in the bath of molten salts by releasing the ag ~ lomératsd'alumine.

The largest dimension of alumina agglomerates or agglomerates mixed alumina and reducing agent, must be between 0.2 and 200 mm, but preferably between 0.5 and 8 mm. ``

In practice, it is desirable that the ag ~ lumerate alumina alone or alumina and carbon and its rivets are well desheated and dehydrogenated according to known calcination processes, to avoid ter, during carbochlorination, the formation of gaseous hydrochloric acid, to the detriment of carbochlora1: ion itself, which consumes would be a fraction of the chlorinated agent inl: produced in the reaction medium nel.
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As the filling of the bath made up of agglomerates is consumed Mable, it is necessary to ensure a regular supply of the medium.
reaction place in agglomerates, so that they are not only source of alumina to be chlorinated, but also maintenance of the gar-nissage so that the total volume occ- ~ by agg ~ alumina lomerate and the molten salt bath is at most twice the apparent volume occupied by agglomerates alone and preferably at most 1.5 times this ~ same apparent wlume.

Finally, the carbochlorination of alumina can be carried out under pres-sion of reaction gases, thus allowing better di ~ fusion of gauze mixture ~ in the molten salt bath. Such a carbon procedure pressure chlorination increases the efficiency of the :.:
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'' alumina in aluminum chloride. `~ -The carbochlorination bath enriched in AlCl3, it is vaporized ~ ized as soon as the composition of the bath allows. He is then trained by gaseous effluents. Aluminum chloride is separated from this gas fraction by any appropriate means known to man art, such as, for example, by condensation of chloride vapor aluminum in a cordensation chamber.

EX ~ LE 1:
This example, which illustrates the prior art, consists of ~ feeding the -bath of molten salts, with alumina in powder form. He illus-also improving the quality of aluminum chloride produced when the reducing agent used is in gaseous form rather than in solid form.

We prepared a salt bath consisting of a mixture of chloride sodium, and aluminum chloride, having the following composition ex-awarded in ~ molar mass:
Sodium chloride ........... 50 Aluminum chloride ......... 50 ~
This bath was ~ subjected to external heating ~ ~ in order to cause fu-of the salt mixture, then it was introduced into a reaction reactor appropriate laboratory previously lined with quartz rings, external diameter 6 millimeters, so that this fully hold the liquid bath. The total height of the bath was about 2.5 meters. The bath temperature was maintained at 650C.
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We added d ~ all ~ inc ~ the state of inc powder prcscnt ~ nt an over-$ ace specific of 77m2 / ~ reason dc 128 g per liter of bath molten salts, which were dispersed by stirring to form a suspension with bath.
Then, a gas mixture was infused into the molten salt bath.
CO and Cl2, of stoechio ~ etric composition, at a rate of 1.3 ~) normal liters per hour and per ~ ramme of al ~ ine introduced, by means of a ~ az diffuser allowing intimate contact within the agitated bath, . ~. . .
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between alwnine grains and dispersed carbochlorination gases within the bath of molten salts. The alumina consumed was replaced at the as and when.
After the bath of molten salts has been saturated with chloride of a: Lwni-niun, the product thus formed vaporized9 was entrained by the ef-gaseous fluids and was collected in a condensation chamber at at a rate of 105 g / h per liter of real bath of molten salts. In these con-ditions, the carbochlorination yield exceeds 95 ~.
Analysis of the aluminum chloride thus produced3 made it possible to note that this one was practically exen ~ t of gold ~ aniques polychlo-res such as hexachlorobenzene, hexachlorethc ~ ne and decachloro-biphenyl.
Found in aluminum chloride thus produced o ~ lexachlore ~ h ~ ne: 40 ppm Hexac] llorobenzene: 10 ppm ~ ecachlorobiphenyl: 2 ppm In order to compare the use of carbon dioxide and solid carbon, we carried out the preparation of anhydrous aluminum chloride by carbon-cllloration in baths of Welded salts, the reluctant element being the bone, all other conditions being equal. The aluminum chloride produced contains:
Hexachlorëtllane: 100 ppm Hexachlorobenzene: 2500 ppm Decachlorobiphenyl: 300 ppm EX ~ ~ LE_2 This example illustrates the subject of the invention. To do this, we have pre-adorned, as in exen ~ le 1, a salt bath consisting of a mixture sodium chloride and aluminum chloride in the proportions `
30 pr ~ cede ~ nent indicated, ~ ui a ~ t ~ subjected ~ la ~ usion dc scs con ~ osants ~ `
and introduced into the reactor of the example, previously packed -d'a ~ glom ~ alwnine rats, the most ~ r ~ llde dimension was included between 2 and 5 millimeters, so that these agglomerates constitute kill the reactor lining and that the total volume occupied by the alumina agglomerates and lc salt bath: melted is the same as lc volwme ap ~ arent occupied by agglomerates alone for the same section of actor. The total height of the garnl bath was 2.5metres ~ uiron.

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The bath temperature was then maintained at 650 ~ C. Then, we have : injected into the round salt bath a gaseous mixture of C0 and C12 of stochiometric composition at a rate of 1.36 normal liters per hour and per gram of alumina introduced, and 51 9 agglomerates were added.
5 alumina rats per hour and per liter of real bath of molten salts.
After the bath of ~ wavy salts has been saturated with aluminum chloride, the product formed vaporized, was entrained by the gaseous effluents and was collected in a condensation chamber at the rate of 132 g / h, per liter of real bath of molten salts.
10 Analysis of the aluminum chloride thus produced made it possible to note that it was practically free of polychloric organic products res such as hexachloro ~ enzyme, hexachloroethane and decachloro-biphenyl7 15 In addition, the introduction of alum: ine in the form of agglomerates of which the smallest grain size was between 2 mm and 5 mm, has improved hourly production by 25 O per liter of reactor.

Using the same conditions as in Examples 1 and 2, this example illustrates the beneficial influence of pressure, established in the enclosure where the carbochlorination takes place, on the yields of transformation of alumina into aluminum chloride.
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To do this, the Applicant carried out in the laboratory reactor 25 above, tests as a function of the pressure prevailing inside of said reactor:
- for aluminas in powder form and in the form of agglomerates, - for a flow of carbochlorination gas of 1.36 normal liters per hour and per gram of alumina introduced Percentage increases in hourly output per liter of reactor were determined for each of the carbochlora tests tion of alumina ~ using utll ~ bathing molten salts of the same composition sition, brought to the same tempera ~ ure of carbochlorination and receiving a 35 quantity of A1203 adjusted to this production '' , - ~!
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9 ~ 7 The experimental results have been collated in Table I below.
after:
TABLE I

Absolute pressure in kg /
~ materials used cm2 in the enclosure of carbochlcration _______ '10. . . __,.
Increase Qo of production A1203 powder Base 100 158 176 per liter of 3 A1203 agglomerated 125 182 212 ~ _ Thus, the table rev ~ the importance of the pressure of ~ az of car-bochloration in the cnceil1te by the import ~ 1te nugnentation pros centa ~ es of hourly production of ~ lCl3 per liter re ~ ctor key.

EX ~ `~ LE 4:
A col1stituted salt bath was prepared by ~ mixture of sodium and aluminum chloride ~ having the following composition, ex-prime in percent of molar mass:
Sodlum chloride ....... 50 Aluminum chloride ..... 50 ~ -This bath was subjected to external heating in order to cause the ~ u-of the salt mixture and then it was introduced into a appropriate laboratory, previously filled with alumina agglomerates, of spherical shape and keys to ~ carbon glomerates, the largest of which dimensions were between 2 and 5 mm, so that these a ~ glomerates constitute the lining of the reactor and that the flight ~ e total occupied by the a ~ carbon alumina glomerates and the Welded salts is the same as the apparent volume occupied by agglomerates merats alone for the same reactor section.
The total height of the bath was approximately 192 m. The temperature of the bath was maintained at ~ 650C.
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. '.' ~ '' ~ 6 ~ 7 Then, the chlorine was blown into the bath with molten salts ~ nitrogenous to 65 normal probe liters per hour and per liter of actual melted melt.
The carbon and a ~ umine consumed were replaced as and when ~
safe. ~ as soon as the molten salt bath has been saturated with chloride of aluminum, the product thus formed vaporized, was entrained by gaseous e-fluents and was collected in a condensing chamber tion ~ 260 g / h per liter of real bath of molten salts.
In ~ the to compare this process with the prior art, we realized the prcpa; ation of anhydrous al ~ inium chloride by carbochlorination in molten salt baths, alumina and carbon being introduced under the form of a fine powder with a particle size between 10 and 200 mi-crons, while all other conditions were, for example elsewhere, apart from the fact that the reactor was lined with rings of quartz with an external diameter of 6 mm. Aluminum chloride production minium was only 163g per hour per liter of actual bath.
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EXI ~ LE 5:
-Was prepared, as in Example 1, a salt bath constituted by a mixture of sodium chloride and aluminum chloride according to the ~ proposals previously indicated, which was subject to the merger of ~
its components.
Then, we introduced into the reactor of Example 1, aggl ~ m ~ -mixed alumina and carbon rats, of substantially cylindrical form that, obtained by coking a paste produced by kneading 25 ~ pitch of coal and alumina at a temperature of 160C. This dough has then was thermally treated at a temperature of 900C for him give good reactivity. These agglomerates included by weight ' 46 ~ of Al203 and 54 ~ of C, the largest dimension of which was taken between 3 mm and 7 mm. These a ~ lomérats constituted the garnissa-age of the reactor in such a way that the total volume occupied by the mixed alumina and carbon agglomerates and the bottom scl bath due either the nîênle ~ ue the apparent volume occupied by the a ~ lomérats only for the same reactor section.
The total height of the garnl bath was approximately 1 ~ m. Then we have 35 added 1450 g of mixed alumina and carbon agglomerates per liter ~ real bath of molten salts. The bath temperature was then maintained at 650C. ~ -. .. ~.
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Finally, chlorine was blown into the bath of molten salts of 62 norma ~ liters per hour and per liter of real bath of dark salts due. The alumina and carbon were replaced progressively.
After the molten salt bath has been saturated with aluminum chloride ~
nium, the product formed vaporized, was entrained by ef-~ gaseous luents and was collected in a condensation chamber at 245 g per hour and per liter of real bath.

EX ~ J ~ LE 6:
A salt bath was prepared consisting of a mixture of chloride of sodium and aluminum chloride having the following composition, ex ~
awarded in percent molar mass: -Sodium chloride ....... 50 ~ 0 Aluminum chloride ..... 50 ~ 0 This bath was subjected to external heating in order to cause the fu-sion of the melan ~ e of salts, then it was introduced clc ~ ns a reactor appropriate laboratory, previously stocked with mixed lomates alumina and carbon.

These a ~ P ~ lomérats, of substantially cylindrical shape, were obtained by coking of a paste made by malaxa ~ e of coal pitch and alumina ~ ~ the temperature of 160C. This paste was then thermally treated ~ the key temperature 900C to give it a good reactivity. These agglomerates have in ~ oids 46 ~ 0 of A1203 and - 25 54 ~ of C. Their largest dimension was between 3 mm and 7 mm.
The total height of the bath was 1.2 m and the temperature of the bath was 650C.

30 Three tests were carried out under the aforementioned conditions, including ~ total olumes occupied simultaneously by ag ~ mixed lomers alumina and carbon and the molten salt bath, for the same dryness tion of reactor, are defined below ~ s:
Test l: total volume equal to the apparent volume occupied by the a ~ glo-mcr ~ ts alone.
F. test 2: total volume false at 1 ~ 2 times the apparent volume occupied by .

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~ 16-agglomerates alone.
Test 3: total volume equal to 1.5 times the apparent volume occupied by agglomerations ~ s alone.

Finally, the chlorine was injected into the bath of molten salts ~ raisc) n of 62 normal liters per hour and per liter of actual salt bath melted.
The alumina and carbon consumed were replaced by ferret ~ measure.

After the molten salt bath has been saturated with aluminum chloride nium, the product formed vaporized, was entrained by ef-gaseous fluids and was collected in a condensation chamber.

The quantities of aluminum chloride produced per hour and per reactor for each test have been recorded in the table below, by setting an arbitrary base of 100 for test 1, the results of tests 2 and 3 being expressed comparatively ~ this base:.
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Hourly production Base d- AlC13 pa ~ liter of actor 100 96 R9 ; Thus, this table rev ~ the possibility of decreasing the ~ olume of ag-glomerates ~ playing the role of ~ jointing while keeping productlons satisfactory AlC13 levels, which allows, in the case of a continuous carbochlorination process, ensuring bath circulation without ~ ent ent ag ~ ylomérats, thanks ~ the presence of a zone bath, or a reserve, deprived of garnissa ~ e.

EXAMPLE 7:
Gn has prepared a key bath constitutes p'lr ~ n ~ mixture of chloride socliwn and aluminum chloride mium, having the following com ~ ositlon express-~ ~.

mée in ~ molar mass:
Sodium chloride ..... 50 Aluminum chloride ... 5Q ~
This bath was subjected to external heating in order to cause the fu-of the salt mixture and then it was introduced into a appropriate laboratory beforehand ~ arni of alumina agglomerates, whose largest dimension was between 2 and 5 mm. These ag-glom ~ rats, of substantially spherical shape, were prepared according to techniques known to those skilled in the art.
The total height of the arni bath was approximately 2.5 m.
Then, 51 g of alumina agglomerates were added per hour and per liter real bath of molten salts. The bath temperature was then held ~ 650C.
Finally, a melanp ~ e ~ azeux was blown into the bath of molten salts of GO and C12 of stoichiometric composition at a rate of 1.36 normal liters per hour and per ~ ram of alwnine introduced. The alumina consumed mée was ren ~ lacée progressively.

Three tests were carried out under the aforementioned conditions, the total volumes occupied simultaneously by the agglomerates of alumina e ~
the molten salt bath for the same reactor section, are challenge ~
nis below:
Test 4: total volume equal to the apparent volume occupied by the ag ~ lo-merats alone ,.
Test 5: total volume equal to 1.2 ~ iis the apparent volume occupied by agglomerates alone.
Test 6: total volume equal to 1.5 times the apparent wlume occupied by agglomerates alone.

After the molten salt bath has been saturated with alumina chloride, the product formed vaporized, was entrained by the effluents ga-;
zeux and was collected in a condensation chamber.

The quantities of aluminum chloride produced per hour and per tre reactor for each ~ test ~ have been consi ~ ned in the table below ~ s by setting an arbitrary base of 100 for test 4, the re--:
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results of tests 5 and 6 being expressed comparatively ~ this based.
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Test Hourly production Base.
by litrc dc 100 9l 82 10 r ~ actor. _ . . ~. .. _. ... l __::

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Thus, the table reveals, ~ in turn, the possibility of reducing the : volume of agglomerate ~ ats playing the role of filling the bath, giving acceptable hourly production of AlCl3 enFore-.

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Claims (19)

The embodiments of the invention, about which an exclusive right of property or privilege is claimed, are defined as follows: 1.- Production process by carbochlorination of anhydrous aluminum chloride consisting of bringing into contact a source of alumina consisting of agglomerates and a chlorinating agent in the presence of a reducing agent in a molten salt bath containing at least one alkali halide and / or alkaline earth, characterized in that, for the purpose to cause intimate contact between the gas phases, liquid and solid, a filling of the bath is formed salts melted by means of said agglomerates.

. 2.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, characterized in that the total volume occupied by the agglomerates alumina merates and the molten salt bath is equal to the volume apparently occupied by agglomerates alone for the same sec-carbochlorination reactor. 3.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, characterized in that the total volume occupied by the agglomerates alumina merates and the molten salt bath is greater than apparent volume occupied by agglomerates alone for a same cross section of carbochlorination reactor. 4.- Carbochlorination production process anhydrous aluminum chloride according to claim 1 or 3, characterized in that the total volume occupied by the agglomerates alumina merates and the molten salt bath is at most two times the apparent volume occupied by the agglomerates alone for the same carbochlorination reactor section. 5.- Carbochlorination production process anhydrous aluminum chloride according to claim 1 or 3, characterized in that the total volume occupied by the agglomerates alumina merates and the molten salt bath is at most 1.5 times the apparent volume occupied by the agglomerates alone for the same carbochlorination reactor section. 6.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, characterized in that the anhydrous alumina agglomerates have their largest dimension between 0.2 and 200 mm. 7.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 6, characterized in that the anhydrous alumina agglomerates have their largest dimension between 0.5 and 8 mm. 8.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, 6 or 7, characterized in that the agglomerates of anhydrous alumina are substantially spherical or cylindrical in shape.

. 9.- Production process by carbochlorination of aluminum chloride according to claim 1, characterized in that the source of alumina introduced into the molten salt is in the form of bars, made from alumina agglomerates linked together by an agent coked or by means of salts used in the composition of carbochlorination bath. 10.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, characterized in that the alumina agglomerates are obtained by mixed agglomeration of alumina powders and agent reducer. 11.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, charac-terized in that the molten salt bath includes in its mass, apart from the alkali halide, from 2 to 60% by molar mass of anhydrous aluminum chloride. 12.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 11, characterized in that the molten salt bath comprises in its mass, apart from the alkali halide, of 10 to 50% by molar mass of anhydrous aluminum chloride. 13.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, characterized in that the chlorinating agent is introduced in the bath of molten salts in stoichiometric proportion compared to the alumina introduced to carbochlorinate. 14.- Carbochlorination production process anhydrous aluminum chloride according to claim 1 or 13, characterized in that the chlorinating agent is chlorine gaseous, CCl4, C2C16, or a mixture of these agents. 15.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1 or 10, characterized in that the reducing agent is selected from the group consisting of carbon, carbon monoxide and dioxalene. 16.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, characterized in that the carbochlorination is carried out under pressure of the reaction gases. 17.- Carbochlorination production process anhydrous aluminum chloride according to claim 1, characterized in that the alkali and / or alkali halide earthy is selected from the group consisting of chlorides lithium, sodium, potassium, calcium, barium and magnesium. 18.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 1, characterized in that the carbochlorination temperature is is in the range of 450 ° C to 900 ° C. 19.- Production process by carbochlorination of anhydrous aluminum chloride according to claim 18, characterized in that the carbochlorination temperature is is in the range of 600 ° C to 800 ° C.