Aluminum Pechiney

Aluminium Pechiney

Pechiney

Joseph Cohen

Alain Adjemian

Pierre Maurel

Gerard Lorthioir

Bernard Jean Gurtner

Yves Bertaud

Jean Michel Lamerant

Henry Mercier

Michel Ferran

This invention relates to a cell for producing a metal by electrolyzing halides in a molten salt bath. It consists of using one cathode in the form of a basket, simultaneously passing a current I.sub.1 between this cathode and an anode in such a manner as to carry out a first deposit of crude metal in the basket and a current I.sub.2 between the said basket and complimentary cathodes for depositing the final metal thereon. The cell consists of a central anodic system, a tubular cathodic basket surrounding the anode and a series of cathodes surrounding this basket, a positioning which cathodes can be reversed in relation to the basket.

Apparatus for the production of a metal by electrolyzing halides in a

A process for the production of aluminum by the electrolysis of anhydrous aluminum chloride produced by the carbochlorination of alumina in a molten salt bath containing at least one alkali metal and/or alkaline-earth metal halide, comprising carrying out the carbochlorination of the alumina and electrolysis of the aluminum chloride in a continuous production loop using the molten salt bath emanating from carbochlorination as the electrolysis bath and the molten salt bath emanating from electrolysis as the carbochlorination bath.

Process for the continuous production of aluminum by the

This invention relates to an electrolysis process and cell for producing a metal by electrolyzing halides in a molten salt bath. It consists of using one cathode in the form of a basket, simultaneously passing a current I.sub.1 between this cathode and the anode in such a manner as to carry out a first deposit of crude metal in the basket and a current I.sub.2 between the said basket and the complimentary cathodes for depositing the final metal thereon. The cell consists of a central anodic system, a tubular cathodic basket surrounding the anode and a series of cathodes surrounding this basket, a positioning which can be reversed in relation to the basket. The invention finds its application in the continuous production of good quality refractory metal with a suitable material and electric yield.

Process for the production of a metal by electrolyzing halides in a

A process for obtaining pure alumina comprising the combination of chlorosulphuric attack of calcined aluminous ores containing impurities, followed by concentration of the liquor obtained after the attack and separation of the sterile material, sulphuric acid treatment of the concentrated liquor followed by chlorination to precipitate almost all the hexahydrated aluminum chloride, separation of the precipitate of hexahydrated aluminum chloride and of the chlorosulphuric mother liquor charged with impurities, pyrohydrolysis of the precipitate to give the desired pure alumina with recycling of released hydrochloric acid, degassing of the chlorosulphuric liquor of impurities with recycling of the gaseous HCl for chlorination, yielding a sulphuric liquor of impurities, finally the elimination of the impurities present in this latter liquor in the form of a sulphuric precipitation by concentration in the presence of potassium ions.

Continuous process for obtaining pure alumina from an acidic liquor

A cyclic process for obtaining very pure alumina by the hydrochloric acid attack of a silico-aluminous material, the said process comprising, in a first stage, the precipitation of at most 75% of the alumina present in the liquor originating from the attack in the form of hexahydrated aluminum chloride which is subsequently decomposed by heating, then, in a second stage, the treatment of the liquor leaving the first stage with HCl gas in order to precipitate dissolved Al.sub.2 O.sub.3 in the form of hexahydrated aluminum chloride which is recycled into the liquor leaving the attack, while the hydrochloric liquor leaving the second stage and impoverished in Al.sub.2 O.sub.3 but rich in impurities, is treated with a recycled sulphuric liquor in order to precipitate impurities as their corresponding sulphates.

Process for obtaining pure alumina by the hydrochloric attack of

A method of obtaining alumina of high purity from aluminous mineral containing impurities by attacking the mineral with a sulphuric acid liquor and separating the resulting liquor from a residue which remains after the attack, the steps of

Method of obtaining pure alumina by acid attack on aluminous minerals

Process for recovering aluminum in the form of a specific acid sulfate from an initial solution containing aluminum in the form of dissolved aluminum sulfate hydrate in which the specific acid sulfate is of the formula Al.sub.2 (SO.sub.4).sub.3.0.5H.sub.2 SO.sub.4.11 to 12 H.sub.2 O and in which the initial solution is sequentially treated in a series of crystallizers, wherein successive crystallizers are maintained at a predetermined decreased generally fixed temperature such that in each crystallizer a state of supersaturation of aluminum acid sulfate exists and the parameters attendant operation of each crystallizer insure that a state of static equilibrium of precipitation of product is generally reached before the process solution/slurry is passed to a successive crystallizer, or filtered for recovery of product.

Process for obtaining an aluminum sulfate hydrate from an impure

Alumina agglomerates with high mechanical strength and selectable particle size are obtained by compacting an intermediate product resulting from incomplete decomposition of a substance of the group comprising hexahydrated aluminum chloride, hydrated aluminum nitrate, hydrated aluminum sulfate of the formula Al.sub.2 O.sub.3, xSO.sub.3, yH.sub.2 O and hydrated aluminum sulfite of the formula Al.sub.2 O.sub.3, xSO.sub.2, yH.sub.2 O, which after thermal decomposition contain from 0.5 to 15% by weight of Cl, of nitrogen oxide expressed as N.sub.2 O.sub.5 or of sulfur expressed as SO.sub.3 or SO.sub.2, which compacted product is then granulated and the granulated product subjected to heat treatment.

Alumina agglomerates with good mechanical strength and a method of

Process for the recovery of H.sub.2 SO.sub.4 from dilute sulfuric acid solutions containing combined acid sulfates by heating these solutions in the presence of excess ammonium sulfate to a temperature from between about 100.degree. and 160.degree. C. until a concentration of free H.sub.2 SO.sub.4 between 50 and 59% by weight is obtained to precipitate the combined acid sulfates.

Recovery of H.sub.2 SO.sub.4 acid

A method of obtaining alumina of high purity from aluminous mineral containing impurities in which the mineral is attacked with a sulphuric acid liquor followed by separation of a liquid phase from the resulting solid residue comprising

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Aix-en-Provence, France

Joseph Cohen