Abstract: The invention concerns a process and an apparatus for applying prestresses to carbonaceous cathodic blocks in the operation of sealing the cathodic bar in position with cast iron.The block (1) in the course of the sealing operation is lifted on two rollers (16A, 16B) in the vicinity of its ends (E) and stresses F1 and F3 are simultaneously applied respectively to the ends (10) of the lateral edges of the limb portions (3) of the block and to the central part (C) of the block. Such stresses must be applied during the sealing operation and maintained for 15 to 30 minutes after the end of the cast iron casting operation.That virtually totally suppresses the occurrence of cracks in the cathodic blocks.

Abstract: The method of the invention concerns continuous graphitization of long pre-cooked carbon-containing products.It comprises displacing the carbon-containing products in a column, along a horizontal axis of passage, inside a furnace where the packing is a fragmented carbon-containing material which is not displaced within the furnace. The column is put under stress by rams and is heated by the Joule effect.The method can be applied particularly to the production of graphite electrodes for arc furnaces in steel works.

Abstract: This invention relates to a muffle furnace, for continuous heat treatment during passage of material therethrough, of products, the production cycle of which includes a treatment of predetermined duration at a temperature which may be about 1100.degree. to about 1150.degree. C., which furnace is heated by a flame producing burner without the combustion gases directly contacting the products to be treated. This furnace comprises: an inlet zone provided with a means for preheating, by circulating recycled combustion gases in a double casing provided around the muffle; a heating zone, provided inside a heat-insulated chamber provided with at least one means for circulating combustion gases around the heating zone of the muffle; and an outlet zone provided with at least one means for controlling the cooling rate of the treated product.

Abstract: The invention concerns a fired refractory product based on refractory grains and binder, and process for the production thereof.The refractory product comprises a charge of refractory grains belonging to the group comprising carbonaceous products such as anthracite, natural graphite, artificial graphite, amorphous carbon, coke, refractory compounds known as RHM such as silicon carbide and refractory oxides such as alumina, corundum, magnesia, silica and chromium oxide, taken separately, in mixture or in combination; said grains are secured together by a cement based on a coked carbonaceous product and metal silicon in powder form; and the final proportion of metal silicon is from 1 to 15.8% and preferably from 3 to 10.5%.The product is intended for the manufacture of side linings for tanks for the production of aluminum by igneous electrolysis, and linings for blast furnaces and electric furnaces for electrometallurgy operations.

Abstract: The invention relates to synthetic carbonaceous granules having high mechanical characteristics and, more particularly, the granules produced from anthracite fines. The invention also relates to a process for the preparation of these granules.These granules are produced by agglomeration of fines to the form of pellets, superficial pre-baking of these pellets by an oxidizing gas at a temperature of between 650.degree. and 1000.degree. C. for a few minutes, followed by calcination at a high temperature and, finally, by crushing permitting the desired granulometry to be obtained.The synthetic carbonaceous granules, according to the invention, are used for all types of application and, in particular, for the manufacture of all types of carbonaceous paste, electrodes and carbonaceous blocks for the linings of furnaces or electrolysis cells.

Abstract: The invention relates to an electric furnace for heating by passing a current through the charge, and more particularly, a continuous furnace in which the charge is a carbonaceous material.The furnace according to the invention is provided with a device for allowing non-reactive gas to be circulated in the opposite direction to the charge.The furnace according to the invention is used, in particular, for calcining anthracite.

Abstract: A nippled joint utilizes a biconical threaded nipple, for joining the ends of graphite electrodes. This new joint involves a particular machining of the threads of each end of the nipple or of the two electrode seats into which the nipple is screwed, which allows a variable clearance to be produced along the threading, this clearance passing through a minimum value into a zone located between a tenth and a quarter of the height of the engaged threading, measured from the base of each seat. A stop system which is produced by shifting at least one thread of the nipple or of the corresponding electrode seat, allows the clearance to be distributed on both sides of the joining plane of the two electrodes. The joint finds great utility in the assembly of electrode columns in an arc furnace and allows them to endure extremely severe thermomechanical strains without breaking.

Abstract: A carbonaceous paste is disclosed which is used at ambient temperature without need for prior heating. The paste contains: at least 70% of calcined carbonaceous material; a low-temperature plasticizing agent such as molasses, a sugar, an alginate or a lignosulfonate; and a high-temperature plasticizing agent such as a dry pitch. The paste is used in particular for luting aluminum electrolysis cells.

Abstract: The invention concerns an improved method of interconnecting carbon blocks intended for the construction of cathodes in cells for electrolysis of aluminum and the steel bars which connect these blocks to the source of current. The method comprises forming the current supplying bars in two portions or half-bars which are housed in channels provided in the carbon blocks, the half-bars being rigidly connected to the blocks by bedding with cast iron or steel. One or more anchoring points provided near the end of the blocks holds the half-bars in position, while the ends of the bars near the middle of the blocks can expand freely in zones left for the purpose.