Abstract: Methods for treating aluminum in a furnace. An aluminum charge is introduced into a furnace and melted with heat from at least one burner. The burner is supplied with at least one oxidizer and at least one fuel. The oxidizer is made up of at least 10% oxygen by volume. The concentration of a first gas is measured in the furnace atmosphere or in a flue gas exiting the furnace. The oxidation of the molten aluminum is then reduced by holding the flow rate of the oxidizer steady while varying the flow rate of the fuel, according to the concentration of a second gas in the furnace or in the flue gas exiting the furnace. The concentration of the second gas is determined by comparing the measured species concentration and the intrinsic concentration which would be present absent the aluminum charge.

Abstract: The invention relates to a method for measuring the quantity of chemical species contained in a high-temperature gas, and especially the quantity of CO and/or CO2 contained in a gas emitted from a metal treating furnace, especially a light-arc furnace (EAF) or a converter (BOF). According to the invention, part of the gas to be analysed is extracted, the temperature of said gas is reduced to at least 300° C., preferably to a temperature that is lower than or equal to 200° C., in such a way as to obtain a at a temperature between 300° C., preferably 200° C., and the ambient temperature, and at least the quantity of CO and/or CO2 said gas is then measured by means of the coherent light signal which is emitted by a laser diode through the gas and is retrieved on emergence from the gas.

Abstract: Methods for treating aluminum in a furnace. An aluminum charge is introduced into a furnace and melted with heat from at least one burner. The burner is supplied with at least one oxidizer and at least one fuel. The oxidizer is made up of at least 10% oxygen by volume. The concentration of a first gas is measured in the furnace atmosphere or in a flue gas exiting the furnace. The oxidation of the molten aluminum is then reduced by holding the flow rate of the oxidizer steady while varying the flow rate of the fuel, according to the concentration of a second gas in the furnace or in the flue gas exiting the furnace. The concentration of the second gas is determined by comparing the measured species concentration and the intrinsic concentration which would be present absent the aluminum charge.

Abstract: The invention relates to a method for measuring the quantity of chemical species contained in a high-temperature gas, and especially the quantity of CO and/or CO2 contained in a gas emitted from a metal treating furnace, especially a light-arc furnace (EAF) or a converter (BOF). According to the invention, part of the gas to be analysed is extracted, the temperature of said gas is reduced to at least 300° C., preferably to a temperature that is lower than or equal to 200° C., in such a way as to obtain a gas at a temperature between 300° C., preferably 200° C., and the ambient temperature, and at least the quantity of CO and/or CO2 in said gas is then measured by means of the coherent light signal which is emitted by a laser diode through the gas and is retrieved on emergence from the gas.

Abstract: The electric arc furnace is equipped with a supersonic injector comprising a so-called Laval nozzle arranged at a certain distance above the bath. The dimensions of the nozzle are calculated as a function of the desired flow rate of oxygen and the desired velocity of the jet, and the pressure of the oxygen at the intake of the nozzle is such that the static pressure of the jet at the exit of the injector is substantially equal to the pressure of the surrounding atmosphere. Preferably, the injector comprises an annular channel for injection of natural gas, and can be used in burner mode at the start of the melting of scrap iron. The velocity of the oxygen is then subsonic.

Abstract: The electric arc furnace is equipped with a supersonic injector (10) comprising a so-called Laval nozzle (20) arranged at a certain distance above the bath. The dimensions of the nozzle (20) are calculated as a function of the desired flow rate of oxygen and the desired velocity of the jet, and the pressure of the oxygen at the intake of the nozzle (20) is such that the static pressure of the jet at the exit of the injector (10) is substantially equal to the pressure of the surrounding atmosphere.