Abstract: Apparatuses and methods for controlling electrode current density of an electrolytic cell during the electrolytic production of a metal, such as aluminum or aluminium, are disclosed. The cell has anodes and cathode plates vertically aligned and arranged in alternating rows. Each electrode defines a connecting region for connecting the electrode to the cell, a middle region, and an ACO (Anode-Cathode Overlap) region extending from the middle region for overlapping adjacent electrodes(s). The ratio of the ACO region's surface area to the middle region's surface area is superior to one. Alternatively, an average cross-sectional ACO region to the middle and connecting regions, is superior than one, preferably superior than 2. The present technology allows maximizing current density in the ACO region.

Abstract: It is disclosed a purifier assembly and method for removing impurities from an electrolytic bath before using the same with an electrolytic cell for making a metal, such as aluminum or aluminium. The assembly comprises a purification tank, located upstream the cell, for containing the bath; and at least one row, preferably at least two rows, of alternating vertically oriented cathodes and anodes configured to be operatively connected to a power supply for providing an electric current to the anodes and cathodes. The rows of vertically oriented cathodes and anodes are configured in size to be inserted into the tank. The purifier assembly is configured to maintain an anode-to-cathode distance (ACD) between the cathodes and anodes. The purifier is particularly adapted for removing sulfur, phosphorus, iron, and/or gallium from cryolite for the eco-friendly production of aluminum with a cell using oxygen-evolving or inert anodes, which preferably requires a purer bath.

Abstract: A method for detecting a thermite reaction in an electrolytic cell comprising an anode assembly of one or more metal-oxide-containing anodes is disclosed. Each anode assembly is powered by a current provided through a distinct anode rod for each anode assembly. The method comprises: measuring a voltage drop using a pair of voltage probes located on the anode rod, the voltage drop corresponding to a current flow in the anode assembly; processing the voltage drop by computing at least one of the voltage drop derivative, the voltage drop variance, and the derivative of the voltage drop variance; and detecting a thermite reaction based on the results of the signal processing, before mitigating and/or suppressing the thermite reaction by adjusting the operational parameters of the electrolytic cell. This method is particularly advantageous as it reduces the number of voltage drops necessary for detecting a thermite reaction by a factor of 10.

Abstract: It is disclosed a system and process for starting up an electrolytic cell. The system and process are particularly adapted for preheating an electrolytic cell or pot having cathodes before installing preheated anodes in the cell, for the production of a metal (e.g. aluminum). The system comprises one or more electrical heaters installed in the cell in place of the anode assemblies and can be used with a dry bath or a liquid melted bath (e.g. cryolite). The cell is preferably preheated by as many cell preheaters as there are anode assemblies. The cell preheater is preferably powered by current available in the pot's busbar. The invention is environmentally friendly as being preferably adapted for preheating a cell working with inert or oxygen-evolving anodes. Furthermore, the starting up process allows optimizing/reducing the time necessary for starting up the electrolytic cell, while securing the materials located inside the cell.

Abstract: An improved electrical connection between an inert anode and a conductor rod is disclosed. The conductor rod has a smaller diameter than a hole in the anode such that a gap is provided between the conductor rod and the anode. The gap is filled with an electrically conductive particulate material, such as Cu, Ni and/or Ag. The particulate conductor material is at least partially sintered before or during operation of the anode. To ensure a good connection between the conductor rod and the anode, the particle size distribution of the particulate connector material may be controlled.

Abstract: A method of protecting an inert anode assembly (16) operating in an electrolysis cell (10) for producing metal when an adjacent assembly (16?) is removed exposing remaining assemblies to low ambient temperatures (40) by utilizing heat radiation shields (24) which can circumscribe every inert anode assembly (16), where the shields (24) remain intact and in place in the cell (10) while operating in molten electrolyte (15) at about 850° C.