Abstract: The invention relates to a method of producing aluminum in an electrolysis cell, which includes setting up a succession of control periods of duration T, identifying perturbative tending operations on the cell that can introduce superfluous alumina in the electrolytic bath, noting the performance of the perturbative tending operations, determining a regulation feed rate B(k?) for each control period k? and setting a specified feed rate SR(k?) equal to M(k?)×B(k?), where M(k?) is a predetermined modulation factor that modulates the regulation feed rate B(k?) so as to take into account a reduction of the needs of the cell induced by the superfluous alumina. The method of the invention makes it possible to significantly reduce the rate of occurrence of anode effects.

Abstract: The invention relates to a method of producing aluminium in an electrolysis cell, which includes setting up a succession of control periods of duration T, identifying perturbative tending operations on the cell that can introduce superfluous alumina in the electrolytic bath, noting the performance of the perturbative tending operations, determining a regulation feed rate B(k?) for each control period k? and setting a specified feed rate SR(k?) equal to M(k?)×B(k?), where M(k?) is a predetermined modulation factor that modulates the regulation feed rate B(k?) so as to take into account a reduction of the needs of the cell induced by the superfluous alumina. The method of the invention makes it possible to significantly reduce the rate of occurrence of anode effects.

Abstract: This invention relates to a method for controlling additions of powder materials into an electrolytic cell designed for the production of aluminium by fused bath electrolysis. The method according to the invention, which can easily be automated, can be used to maintain monitoring of operation of the feed even during anode effects.

Abstract: This invention relates to a method for controlling additions of powder materials into an electrolytic cell designed for the production of aluminium by fused bath electrolysis. The method according to the invention, which can easily be automated, can be used to maintain monitoring of operation of the feed even during anode effects.

Abstract: A method for measuring temperature and electrolyte level of a molten electrolysis bath in a cell for production of aluminum by electrolysis of alumina includes the steps of: (a) piercing the crust of a solidified bath with a crust breaker and immersing into the electrolyte, an extremity of a temperature probe to a sufficient depth until an initial temperature reading of at least 850.degree. C.

Abstract: The invention relates to a process for regulating the acidity of the electrolytic bath by recycling fluorinated effluents emitted by the Hall-Heroult electrolytic cells for the production of aluminum, in which said fluorinated effluents are collected, by the dry route, on the alumina. It comprises the following stages:a reference value for the fluorine/alumina weight ratio is fixed in connection with the alumina leaving the collecting apparatus,a continuous measurement takes place of the fluorine and alumina quantities entering the collecting apparatus,the alumina flow rate is regulated so as to maintain the F/Al.sub.2 O.sub.3 ratio at its reference value, generally fixed between 0.

Abstract: Process and apparatus for controlling solid electrolyte additions to electrolytic cells for aluminum production.The invention relates to a process for controlling solid electrolyte additions to a cell for producing aluminum by the electrolysis of alumina dissolved in a molten cryolitic bath according to the Hall-Heroult process.According to this process a nominal value HBC is fixed for the bath height, the level of the bath in the cell is periodically determined on the basis of a fixed dimension point PF known relative to the carbon-containing cathode substrate, from it is deduced the total height HT of the electrolytic bath layer HB and the liquid aluminum layer HM, the thickness HM of the liquid aluminum layer on the cathode substrate is determined, from it is deduced the bath layer height HB, HB=HT-HM and Hb is compared with the nominal value HBC.

Abstract: A process for automatically going into the mode for increased suction extraction of the gases emitted by the tanks of series for the production of aluminium by igneous electrolysis using the Hall-Heroult process, each tank being closed around its periphery by a plurality of removable covers which are disposed in substantially sealed relationship with each other and between each thereof and their support means on the periphery of the tank, the gases being collected over each tank by at least one duct connected to a centralized suction extraction system.The temperature of the gases in the duct is continuously measured. Opening of at least one cover gives rise to an abrupt drop in temperature, which makes it possible to put the system into the increased suction extraction mode, which will be automatically stopped when, all the covers being closed again, the temperature of the gases will substantially resume its initial value.The power required for the suction system is thus substantially reduced.

Abstract: The invention relates to a process for packing, also known as lining, electrometallurgical furnaces.The packing is produced from a concrete which is poured in situ or in precast blocks, composed of a setting cement having a low water retention capacity and low porosity and of an aggregate of which at least a proportion is a carbonaceous product such as anthracite. This packing has a noteworthy resistance to the constituents of fluoride-based igneous electrolysis baths and to liquid aluminum.Application to the packing of igneous electrolysis cells for the production of aluminum.