Abstract: A method is presented for the treatment of slag from electric steel plants which comprises the following steps: (a) transference of the slag into a metallurgical receptacle; (b) defoaming of the slag in this metallurgical receptacle by adding a defoaming agent, preferably silica; (c) subsequent heating of the slag to make it fluid; and (d) forced cooling of the slag, for example by an aqueous granulation.

Abstract: A method is presented for the treatment of slag from electric steel plants which comprises the following steps: (a) transference of the slag into a metallurgical receptacle; (b) defoaming of the slag in this metallurgical receptacle by adding a defoaming agent, preferably silica; (c) subsequent heating of the slag to make it fluid; and (d) forced cooling of the slag, for example by an aqueous granulation.

Abstract: A method for making steel in an electric furnace, wherein a predetermined amount of liquid melt is fed into the electric furnace. The method comprises the steps of (a) continuously feeding a controlled flow of liquid melt into the furnace without interrupting the heating from the electric arc, (b) continuously injecting a refining gas into the furnace before the C and/or Si content of the metal bath reaches a predetermined value, until the end of the feeding process, and (c) pursuing the injection of refining gas after the predetermined amount of melt has been fed into the furnace, until the target value for the C and/or Si content of the metal bath has been reached.

Abstract: For improving permeability of a metallurgical vessel bottom provided with permeable refractory elements for controlled injection of a stirring fluid into a molten metal bath, the metallurgical vessel is emptied of its contents, a castable composed of a refractory material compatible with the refractory material of the bottom is deposited in the bottom and spread over the latter, and the castable is left to dry and set, while maintaining in the permeable refractory elements a sufficient pressure to provide a permanent flow of a stirring fluid. A hydraulic magnesian refractory castable used in this method has a content of water of substantially between 8 and 10% by weight.

Abstract: The service life of permeable refractory elements is improved by conserving in a vessel a fluid slag formed during refining of a charge after a liquid metal has been cast by tipping the vessel, depositing and spreading the slag over the bottom by bringing the vessel back to its upright position, and leaving the slag to harden and set on the bottom, while a sufficient pressure is maintained in the permeable refractory elements to ensure a permanent flow of a stirring fluid.

Abstract: For improving permeability of a metallurgical vessel bottom provided with permeable refractory elements for controlled injection of a stirring fluid into a molten metal bath, the metallurgical vessel is emptied of its contents, a castable composed of a refractory material compatible with the refractory material of the bottom is deposited in the bottom and spread over the latter, and the castable is left to dry and set, while maintaining in the permeable refractory elements a sufficient pressure to provide a permanent flow of a stirring fluid. A hydraulic magnesian refractory castable used in this method has a content of water of substantially between 8 and 10% by weight.

Abstract: The service life of permeable refractory elements is improved by conserving in a vessel a fluid slag formed during refining of a charge after a liquid metal has been cast by tipping the vessel, depositing and spreading the slag over the bottom by bringing the vessel back to its upright position, and leaving the slag to harden and set on the bottom, while a sufficient pressure is maintained in the permeable refractory elements to ensure a permanent flow of a stirring fluid.

Abstract: Installation according to the invention comprising a desilication and dephosphorization stage (A), followed by a decarburization stage and in which the pig iron to be pre-smelted is intended to form a bath whose free surface is maintained at a predetermined level (N.sub.1).The dephosphorization comprises a reactor (1) comprising means (5, 6, 8) respectively for introducing the pig iron to be pre-smelted, for adding desilication and dephosphorization agents, and for creating an oxidizing atmosphere, as well as rabbling means (9). It also comprises a decanter (2) separated from the reactor (1) by a partition (3) having an opening (4) below the level (N.sub.1) and whose upper end is above the latter. The decanter comprises an immersed outlet opening (10) connected to the decarburization stage and an overflow (12) for evacuating the slag. The slag formed in the reactor (1) flows out in the decanter (2), overflows above the partition (3), and moves toward the overflow (12) which evacuated it.

Abstract: Process of refining of a metal bath in a crucible with oxygen blast at the top and crucible used.The invention consists essentially of providing in the bottom (15) of the crucible agitating gas injectors (15) located at least in a peripheral circular ring situated in immediate proximity to the refractory side wall. The injectors are preferably concentrated opposite the journals. Secondary injectors are, also preferably, provided in the bottom zone, intermediate between the ring and the center of the crucible.The invention makes it possible, in relation to the prior injection practice, to reduce the rate of dissolution of the agitating gas in the molten metal and then makes it possible to use a low-cost agitating gas, such as nitrogen, without risk of excessive nitridation of the bath.

Abstract: Stainless steel is produced in a converter with a tuyere defining a central conduit and a peripheral conduit concentrically surrounding the central conduit, by blowing an oxidizing refining gas through the central conduit into a molten metal bath, the refining gas initially consisting of pure oxygen and being subsequently diluted by gaseous argon, and injecting liquid argon into the converter through the peripheral conduit, to refine the molten metal bath until it has attained a desired level of carbon.

Abstract: A method for making steel in an electric furnace, wherein a predetermined amount of liquid melt is fed into the electric furnace. The method comprises the steps of (a) continuously feeding a controlled flow of liquid melt into the furnace without interrupting the heating from the electric arc, (b) continuously injecting a refining gas into the furnace before the C and/or Si content of the metal bath reaches a predetermined value, until the end of the feeding process, and (c) pursuing the injection of refining gas after the predetermined amount of melt has been fed into the furnace, until the target value for the C and/or Si content of the metal bath has been reached.