Abstract: A method for producing a weak resistance injection element for introducing ases into molten metals.The injection element includes an assembly of at least two high density refractory components. At least the upper high density refractory component is made by isostatic pressing of ceramic powders followed by a double heat treating process which are selected according to the liquid metal to be melted/refined in the metallurgical vessel where the injection element is going to operate.

Abstract: Wax, alloy or plastic molds for containers used in hot isostatic pressing of metal and/or ceramic powders are surface conditioned for electroplating, coated with several metallic layers and removed from the resulting container.

Abstract: A method to improve the service life of gas injection devices is disclosed.A porous mushroom with controlled permeability is formed, previously to the element installation, in the tip of said element by a thermal spray process.By controlling gas flow rate and pressure during the mushroom formation, the gas permeability in said mushroom is controlled.The sprayed materials are high melting point ceramics, metal compounds or synthetic slags.

Abstract: The present invention relates to a method and a fluid injection device for quick replacement, even in the red hot conditions, in a metallurgical reactor. The method comprises the external extraction of the injection device which is composed of an inner extractable blowing element and wear resistant block, element the blowing element secured in the wear resistant block and forming together the injection device. The quick interchange is first performed by extracting the inner blowing element, then installing a special extractor device in the space where the blowing element was and then extracting the wear resistant block by applying a force, in the opposite direction of the gas flow, through the bottom end of the extractor device. The extractor device has a special design so, when a force is applied at its bottom end, an expansive occurs at the upper end making the external extraction of said wear resistant block easier.

Abstract: A method for the improvement of the process for the refining of liquid metals by means of the injection of natural gas.It is upon the lab and semi-industrial plant experience of the inventors of the present invention, that it was found that during the injection of natural gas into liquid metals, there is substantially no cracking of methane under usual conditions of pressure and temperature in the refining processes.In such conditions, natural gas can be used as inert gas in metallurgical processes with technical and economical advantages over inert gases, introducing it through the bottom of the liquid bath. This practice has in addition, the property of reinforcing the process conditions, oxidizing or reducing, according to the slag in the molten bath.

Abstract: A process to improve electric arc furnace steelmaking. The efficiency increase is due to the metal-slag stirring that is produced by bottom gas injection through gas permeable ceramic elements. The permeable elements are not penetrated by the liquid metal, which does not stop the gas flow.The process is carried out in combination with a furnace charging door stopper device. The device avoids liquid ejections through the furnace charging door during the injection periods. The electric arc furnace steelmaking generalized practices are more effective when the molten metal is being stirred by gas injection, by increasing the metal-slag and the slag-atmosphere interphase area. When the stirring gas is natural gas, the process conditions, oxidizing or reducing, are reinforced according to the slag in the bath.