The invention relates to a process for producing low-nitrogen crude steel. This process includes melting directly reduced iron and/or scrap in a melting furnace with arc resistance heating to give a metallic melt and a slag. The metallic melt is removed from the melting furnace and used to charge a converter. The metallic melt is refined in the converter to give liquid crude steel. The liquid crude steel is tapped having a nitrogen content [N] of not more than 50 ppm, especially of not more than 30 ppm.

The invention relates to a process for producing low-nitrogen crude steel. This process includes melting directly reduced iron and/or scrap in a melting furnace with arc resistance heating to give a metallic melt and a slag. The metallic melt is removed from the melting furnace and used to charge a converter. The metallic melt is refined in the converter to give liquid crude steel. The liquid crude steel is tapped having a nitrogen content [N] of not more than 50 ppm, especially of not more than 30 ppm.

A direct reduction plant is disclosed. The direct reduction plant includes an oxygen injection system, a reformer, and a shaft furnace. The oxygen injection system includes an oxygen injection reactor and a main oxygen burner. The oxygen injection reactor is adapted to receive a gas mixture. The main oxygen burner is adapted to increase a temperature of the gas mixture by burning a mixture of fuel and oxygen fed to the main oxygen burner. The reformer is adapted to reform the gas mixture with the increased temperature. The shaft furnace is adapted to reduce iron ore using the reformed gas mixture.

A direct reduction plant is disclosed. The direct reduction plant includes an oxygen injection system, a reformer, and a shaft furnace. The oxygen injection system includes an oxygen injection reactor and a main oxygen burner. The oxygen injection reactor is adapted to receive a gas mixture. The main oxygen burner is adapted to increase a temperature of the gas mixture by burning a mixture of fuel and oxygen fed to the main oxygen burner. The reformer is adapted to reform the gas mixture with the increased temperature. The shaft furnace is adapted to reduce iron ore using the reformed gas mixture.

A direct reduction method/system, including: adding variable amounts of natural gas, hydrogen, and a carbon-free oxidizing gas to a feed gas stream upstream of a reformer; reforming the feed gas stream in the reformer to form a reformed gas stream, and delivering the reformed gas stream to a shaft furnace, where the reformed gas stream is used to reduce a metallic ore material to a direct reduced metallic material. The feed gas stream includes a top gas stream recycled from the shaft furnace. Optionally, the carbon-free oxidizing gas includes steam and the method further includes controlling a steam flow rate of the steam to maintain a maximum k-factor value of the feed gas stream of 0.74 or lower. Optionally, the variable amount of hydrogen is selected to replace 20-90% of the natural gas by fuel value. The variable amount of hydrogen is selected based upon an available supply of hydrogen.

A direct reduction method/system, including: adding variable amounts of natural gas, hydrogen, and a carbon-free oxidizing gas to a feed gas stream upstream of a reformer; reforming the feed gas stream in the reformer to form a reformed gas stream, and delivering the reformed gas stream to a shaft furnace, where the reformed gas stream is used to reduce a metallic ore material to a direct reduced metallic material. The feed gas stream includes a top gas stream recycled from the shaft furnace. Optionally, the carbon-free oxidizing gas includes steam and the method further includes controlling a steam flow rate of the steam to maintain a maximum k-factor value of the feed gas stream of 0.74 or lower. Optionally, the variable amount of hydrogen is selected to replace 20-90% of the natural gas by fuel value. The variable amount of hydrogen is selected based upon an available supply of hydrogen.

A method for recycling used cells such as saline cells, alkaline cells, button cells and used rechargeable batteries, includes the step of introducing the cells and/or rechargeable batteries as feedstock into a metal melting furnace, at the charging door thereof. The cells and/or rechargeable batteries are subjected to a compression operation in order to remove the electrolytes contained in the cells and/or rechargeable batteries, prior to introducing the cells and/or rechargeable batteries into the metal melting furnace.

The method can be used for recycling used cells and rechargeable batteries.

A device for determining the topography of the burden surface in a shaft furnace (10), the device comprising a radar device (20) that scans the burden surface (18) and has an antenna device (22) arranged in the area of a furnace cover (13), the antenna device being arranged on an axis of rotation (24) that is inclined in relation to a vertical axis (15) of the shaft furnace at an angle of inclination and being rotatable about the axis of rotation by means of a drive device in such a manner that a radar fan beam (28) formed by the emitted radar radiation of the antenna device is incident upon the burden surface along a profile line p and sweeps across the burden surface as the antenna device rotates.

A device for determining the topography of the burden surface in a shaft furnace (10), the device comprising a radar device (20) that scans the burden surface (18) and has an antenna device (22) arranged in the area of a furnace cover (13), the antenna device being arranged on an axis of rotation (24) that is inclined in relation to a vertical axis (15) of the shaft furnace at an angle of inclination and being rotatable about the axis of rotation by means of a drive device in such a manner that a radar fan beam (28) formed by the emitted radar radiation of the antenna device is incident upon the burden surface along a profile line p and sweeps across the burden surface as the antenna device rotates.

A direct reduction plant is disclosed. The direct reduction plant includes an oxygen injection system, a reformer, and a shaft furnace. The oxygen injection system includes an oxygen injection reactor and a main oxygen burner. The oxygen injection reactor is adapted to receive a gas mixture. The main oxygen burner is adapted to increase a temperature of the gas mixture by burning a mixture of fuel and oxygen fed to the main oxygen burner. The reformer is adapted to reform the gas mixture with the increased temperature. The shaft furnace is adapted to reduce iron ore using the reformed gas mixture.