US2783991A - Apparatus for extraction of aluminium - Google Patents

Description

March 5, 1957 P. MORIZE APPARATUS FOR EXTRACTION 0 ALUMINIUM Filed May 5, 1955 IN l/EN TOR. Pierre Mar/2e M A HIS Arron/5Y greater than :are=formed, located inside the of a bell shaped United States 2,783,991 APPARATUS FOR EXTRACTION F ALUMINIUM Application May 5, 1955, Serial No. 506,339 7 Claims (Cl. 26635) The present invention relates to a device for the commercial extraction of aluminium from its alloys or from material in which it is contained.

This device is intended for carrying into etfect the known method which consists in the reaction on these alloys or materials, at a suitable temperature, of an aluminium halogenide so as to form a volatile sub-halogenide which is then cooled in a separate chamber in such a Way as to cause the separation in the pure state of the aluminiurn absorbed and the liberation of the initial halogen salt, which is recovered and re-cycled.

This process has, up to the present time, been carried out at a relatively low pressure, which has given rise to ditficulties of isolation and fluid-tightness together with the necessity of handling .large volumes of gas by reason of the low density of the gases at low pressure.

Finally, since the period of contact of the halogenide withthe primary material is short, the necessary balance of concentration of the sub-halogenide cannot be obtained.

{The present invention has for its object a device for carrying into effectaprocess of the kind referred to, device beingdesigned to overcome the drawbacks mentioned above. Said deviceessentially comprises anupper tank adapted to contain the molten starting material and forming a reaction chamber closed at its upper portion, its walls being maintained at a temperature equal to or that of the said molten material ,to be treated, a supply conduit for bringing the aluminium halogenide through a gas-dividing member, one of the facesor" which is in contactwith the said molten metal, .anevacuation pipe forthe gaseous sub-halogenides which tank and passing through the said tank and the molten materialina-fluid-tight manmet, a decomposition chamber in which terminates the said evacuation pipe andta tan-k "for receiving pure metal drawn-ofi" from the base-of the said decomposition cham- 'ber,-which is, in additiomprovided with-a conduit-for the recovery oft-he gases which are-formed therein.

The reaction chamber is preferably formed by means member which plunges into theupper tank. The said bell-shaped member'is advantageously provided withtloublewalls providingan internal space adapted to receive a molten metal. Means are of course provided-toobtainthe necessary temperatures in the various parts of theapparatus.

The gas-dividingmemberrnay be a plug made of porous materiaL'a plate provided with a plurality offholes ora-multitnbular dilfuser.

The present invention is explained below in -greater detail with reference to the attacheddrawings which illustrate various embodiments thereto, and in which:

(Fig. 1 is a view in'diagrammatic crqss-sectionof a device used in th e extractionpf ,alumi f n in accordance w t 'the r s i e ti nf'Fj -j an arealt r a ir tQEJ lsgtrtabefiiasatp agdevice of thejlkind referredgto. i

. single orifice closed by 2,783,991 estes! Me 5, we?

tion" of aluminium comprises a tank :1 bell 2 havin g double walls. i I "The tank is provided, on the one hand ,with anorifi ce cl sed by meansof a porous plug3 which rr'iayals'o be, for .eiiample, afplat'e pierced with a number ofholes orev multitubular diffuserfcommunicating witha onduit' which leads the halogen'id'e to a char iiber 5; H T '1 0n the other hand, a furtherorificeisfiorrned in the said tank through which is passed aif extraction ,t'ub made of material which is not attacked by'inl n minium such as, for example, calcined alum na. tube 6 leads into a chamber 7, the-loweripar't'o constitutes a tank 3 and the upper part is'provid a conduit9 ,for evacuating the halogen com" nd. The whole assembly comprised by the porou's'plug 3, the tank 1 and the hell 2, is maintained 'by ihfiatcr's'jfl at a temperature comprised between 1100 and ;1 4Q'0, C. The chamber t7 and the tanks are maintained 'by'aheater 38 at a temperature below 100 O 'C. but above the point of aluminium, the tube d and .the'conduit f brought up to a temperature which is at least equa to the temperature at which the vapour te l ion of th halo'gen In addition, the t I liquid primary material and is thus maintainedlat this perature of this latter. V

The advantage of an arrangement of the present kind is that it enables the operation to, Qecarried out i a semi-continuous manner. It is actually po bl ;tract the primary material,

Wheth'e'r';ino1te or n time to time fromtheannular space bet the t n an fi W' fi wn it the a from the action of the halogen compound. material.

In the same way, it is possible to take off from the tank 8 the quantities of pure aluminiumlso,formed,.witliinthe limit n s s ar oim mein .a u tabteleyel .o f;thi liquid metalinthe chamber 7.

,Fig. 2 shows an alternative form of embodiment in which the tank -21 of refractory material, .such as 9 0% AlzO310% SiOz, for example, is provided ,with ,a-ibell 22 v, of the same material. The ltankvispiercedwith a means of a porous plug 423 through which, the halogen compound is passed through thei medium .of an iron tube -24, tintothe chamber 25' wlgich isfurthermore-limited ,by .a metal plug :2 1'c,;for example of molten lead, resting one, bed 2,111,. lheinature 5 f whichwill be definedbelow. i

' An extraction tube 26 of, for,example, calcinedlaluniina leads'into acham'oer'27 through a. plug 27,:zjatidla joint 27b; ,atthe lowerpart of the ch amber is; provided .a tank g of graphite for examplatromhwhich thel alogen compound can pass out at Z9 andlcan: here-cycled .att30. The tank 21 issupportedon an insulatingbed zlacontained in a plate 2111, said bed being of granulatedtheatinsulating material.

@111 Fig. 3, thetank 31 ofrefractorvmaterial. O 10% Si02 for example) ,1 is provided ,with a bell 32 of the same material. The tank is piercedjwithtah orifice, provided witha porous plug 33;;3, .through;,which passes the halogen compound which is; ,led through an are made of aluminous porcelain and which pass through a plug 35a and a joint 35b. v

The extraction tube 36' is of calcined alumina and enables the sub-halogenide to be evacuated, the halogenide being re-cycled as previously described, from a chamber formed above a tank (not shown) in which are collected respectively the halogen compound and the pure aluminium product.

It will be seen that in all the forms of embodiment shown (comprising a tank with a flat base, a raised base or a base with a depression) there has been provided a fluid-tight passage for the tube which evacuates the subhalogenides formed.

In Fig. l, the molten metal contained in the tank 1 itself serves as a point providing the fluid-tight passage of the evacuation tube 6 into the tank 7.

.'In Fig. 2, the molten metal contained in the tank 21, the molten lead 21c and the joint 27bensure in combination the fluid-tight passage oithe conduit 26.

In Fig. 3, the molten metal contained in the tank 31 and the joint 35b carry out the same function.

In Figs. 2 and 3, the arrangements for maintaining the temperature of the upper tank have not been shown and the details of the bell have also not been described, the latter being preferably a bell with double walls identical with that of Fig. 1.

In all the devices shown, the process is as follows: The halogen compound passes through the porous plug from the bottom to the top, the necessary pressure being applied to it to that end, and bubbles into the molten primary material. The sub-halogenide which results from the reaction is collected in the upper portion of the bell and passes into a decomposition chamber at the base of which is collected the liquid pure aluminium which forms in the tank provided for that purpose.

There are given below, by way of example, some results of the treatment carried out in the devices shown in Figs. 1 and 2.

Example 1 Using the device shown in Fig. l, a. bath of metal to be purified was heated to 1250 C. for 3 hours 30 minutes, and through this bath 275 grams of aluminium chloride were passed. 42 grams of pure aluminium were subsequently collected and the efficiency of the operation amounted to 38%.

Example 2 Using the arrangement shown in Fig. 2, a bath of metal to be purified was heated to 1200 C. for hours, and through this metal bath was passed 370 grams of aluminium chloride. 45 grams of pure aluminium were collected and the efiiciency of the operation was 30%.

' What we claim is:

1. An apparatus for commercial extraction of aluminum from aluminum containing alloys or like materials, comprising an upper tank adapted to contain the starting material in a molten state up to a given level, forming a reaction chamber having a gas-tight upper part, means for heating said tank, a supply conduit adapted to be connected to a source of aluminum halogenide opening in the lower part of said tank through a gasdividing member, an evacuation pipe passing through said tank in a fluid-tight manner and having an upper end opening in the upper part of said reaction chamber above the level of the starting material therein, and a lower end opening in a gas-tight decomposition chamber, a gas draw-oil pipe opening in said decomposition chamber and a draw-off tank connected to said decomposition chamber beneath said chamber, means being provided for heating said decomposition chamber and draw-0E tank.

-2. An apparatus for commercial extraction of aluminum from aluminum containing alloys or like materials, comprising an upper tank adapted to contain the substantially vertically,

starting material in a molten state up to a given level and having an open upper part, a bell-shaped container having lateral walls extending downwards into said tank through said open upper part, below said level of said starting material, thereby forming a reaction chamber within said tank, means for heating said tank and said bell-shaped member, a supply conduit adapted to be connected to a source of aluminum halogenide opening in the lower part of said tank through a gas-dividing member, an evacuation pipe passing through said tank in a fluid-tight manner and having an upper end opening in the upper part of said reaction chamber above the level of the starting material thereinto, and a lower end opening in a gas-tight decomposition chamber, a gas draw-ofi pipe opening in said decomposition chamber and a drawofi tank connected to said decomposition chamber beneath said chamber, means being provided for heating said decomposition chamber and draw-oil tank.

3. An apparatus as claimed in claim 1, in which said lateral walls of said bell-shaped member are double walls providing an internal space adapted to receive a molten metal.

4. An apparatus for commercial extraction of aluminum from aluminum containing alloys or like materials, comprising an upper tank adapted to contain the starting material in a molten state up to a given level and having an open upper part, and a substantially fiat bottom provided with a first and second opening, a bell shaped container having lateral double walls providing an internal space adapted to receive a molten metal and extending downwards into said tank through said open upper part, below said level of said starting material, thereby forming a reaction chamber within said tank, means for heating said tank and said bell-shaped member, a gasdividing member tightly fitted in said first opening, a supply conduit having one end adapted to be connected to a source of aluminum halogenide and another end opening under said gas-dividing member and tightly connected to the bottom of said tank, an evacuation pipe passing through said second opening in a fluid tight manner and having an upper end opening in the lower part of said tank through a gas-dividing member, an evacuation pipe passing through said tank in a fluid-tight manner and having an upper end opening in the upper part of said reaction chamber above the level of the starting material therein, and a lower end opening in a gas-tight decomposition chamber, a gas draw-0E pipe opening in said decomposition chamber and a draw-0E tank connected to said decomposition chamber beneath said chamber, means being provided for heating said decomposition chamber and draw-oil tank.

5. An apparatus for commercial extraction of aluminum from aluminum containing alloys or like materials, comprising an upper tank adapted to contain the starting material in a molten state up to a given level, and having an open upper part, a bottom with a central raised portion encircling a single opening having walls extending a bell-shaped container having lateral double walls providing an internal space adapted to receive a molten metal and extending downwards into said tank through said open upper part and resting upon said central raised portion of the bottom of said tank, an annular gas-dividing member tightly fitted in said single opening in said raised portion of the bottom of said tank and having a substantially central opening, a supply conduit having one end adapted to be connected to a source of aluminum halogenide and another end opening under said gas dividing member and extending substantially axially between the walls of said single opening in said raised portion, an annular plug between said conduit and said walls of said single opening, an evacuation pipe arranged substantially axially in said conduit and passing tightly through said central opening in said gas-dividing member, said evacuation pipe having an upper end opening in the lower part of said tank through a gas-dividing member, an evacuation pipe passing through said tank in a fluid-tight manner and having an upper end opening in the upper part of said reaction chamber above the level of the starting material therein, and a lower end opening in a gas-tight decomposition chamber, a gas draw-ofi pipe opening in said decomposition chamber and a draw-01f tank connected to said decomposition chamber beneath said chamber, means being provided for heating said decomposition chamber and draw-off tank.

6. An apparatus as claimed in claim 5, in which the bottom of said upper tank is supported on a bed of granular, heat insulating material carried in a shallow circular tray having an opening for the passage of said supply conduit, said granular material also serving as a support for said annular plug.

7. An apparatus for commercial extraction of aluminum from aluminum containing alloys or like materials, comprising an upper tank adapted to contain the starting material in a molten state up to a given level and having an open upper part and a bottom with a downwardly projecting, central portion contained by lateral walls of substantial depth and thickness and providing a single, central opening in said bottom, a bellshaped container having lateral double walls providing an internal space adapted to receive a molten metal and extending downwards into said tank through said open upper part and resting on said lateral walls of said central portion, a supply conduit having one end adapted to be connected to a source of aluminum halogenide and another end tightly fitting in said opening in the bottom of the tank, an annular gas-dividing member tightly fitted in said other end of said conduit and having a substantially central opening, an evacuation pipe arranged substantially axially in said conduit and passing tightly through said central opening in said gas-dividing member, said evacuation pipe having an upper end opening in the lower part of said tank through a gas-dividing member, an evacuation pipe passing through said tank in a fluid tight manner and having an upper end opening in the upper part of said reaction chamber above the level of the starting material therein, and a lower end opening in a gas-tight decomposition chamber, a gas draw-off pipe opening in said decomposition chamber and a draw-off tank connected to said decomposition chamber beneath said chamber, means being provided for heating said decomposition chamber and draw-off tank.

References Cited in the file of this patent UNITED STATES PATENTS 2,697,597 Weiss Dec. 21, 1954

Claims (1)

1. AN APPARATUS FOR COMMERICAL EXTRACTION OF ALUMINUM FROM ALUMIMUM CONTAINING ALLOYS OR LIKE MATERIALS, COMPRISING AN UPPER TANK ADAPTED TO CONTAIN THE STARTING MATERIAL IN A MOLTEN STATE UP TO A GIVEN LEVEL, FORMING A REACTION CHAMBER HAVING A GAS-TIGHT UPPER PART, MEANS FOR HEATING SAID TANK, A SUPPLY CONDUIT ADAPTED TO BE CONNECTTED TO A SOURCE OF ALUMINUM HALOGENIDE OPENING IN THE LOWER PART OF SAID TANK THROUGH A GASDIVIDING MEMBER, AN EVACUATION PIPE PASING THROUGH SAID TANK IN A FLUID-TIGHT MANNER AND HAVING AN UPPER END OPENING IN THE UPPER PART OF SAID REACTION CHAMBER ABOVE THE LEVEL OF THE STARTING MATERIAL THEREIN, AND A LOWER END OPENING IN A GAS-TIGHT DECOMPOSITION CHAM-

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