Aluminium Pechiney

Rio Tinto Alcan International Limited

Raymond Roumieu

Christian Cloue

Jean-Michel Lamerant

Jean-Marc Rousseaux

Mehrdji Hemati

Odissefs Keramidas

Cécile Plais

A process for transporting a powder material, in which a device is fitted between a supply zone and a zone to be supplied, the device including at least one substantially horizontal conveyor which includes a lower duct and an upper duct being separated by a porous wall, the upper duct provided with a balancing column. The upper duct is filled with powder material and the lower duct is supplied with gas at a pressure that allows the potential fluidization of the powder material in the upper duct. The minimal bubbling speed, which corresponds to the maximum void fraction, is determined and the fluidization pressure is set to a value such that the fluidization speed of the gas is between 0.8 and 1.5 times the minimal bubbling speed, preferably between 0.9 and 1.3 times the minimal bubbling speed.

Process for conveying powdery materials without segregation

A method for the production of aluminum from bauxites containing aluminum monohydate of the diaspore or boehmite type which may contain more than 1.5% by weight of calcium carbonates. The ore is digested by producing feeding a suspension produced from milled bauxite ore and concentrated aluminate liquor to a plant with a series of autoclaves and a series of regulators supplying tubular reheaters across the autoclaves with steam. The suspension first travels across the series of autoclaves, and on exiting, the digestion of the ore is practically complete, and the suspension then travels across the series of regulators. The condensation water from the steam coming from the regulator and feeding the reheater is collected in a purge pot. Within the series of regulators, the suspension is diluted on entering a regulator with the water coming from the condensation of the steam from one or several upstream regulators.

Solubilisation of carbonates by recycling condensates during digestion of monohydrate bauxites under pressure

Method for conveying a pulverulent material making it possible to divide said pulverulent material, from a single storage capacity (), between several conveyors () with a controlled flow rate in each of said conveyors, characterized in that said storage capacity is linked to said conveyors by at least one aero-pipe () and in that a hyperdense fluidized meter (), is connected to said aero-pipe, said hyperdense fluidized meter being intended to feed each of the conveyors.

System for distribution of pulverulent material with controlled gravimetric flow rates

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Aix en Provence, France

Raymond Roumieu