A method for processing iron ore to obtain steel

A method for processing iron ore to obtain steel, the method comprising the steps of:

• introducing iron ore into a gas reduction unit so as to subject said iron ore to a direct reduction process for obtaining direct reduced iron, wherein said iron ore comprises:
• a silica (SiO2) content of at least 3% by mass,
• an iron content of no more than 65% by mass, and
• a phosphorus oxide (P2O5) content of at least 0.015% by mass;
• introducing said direct reduced iron into a smelting furnace so as to subject said direct reduced iron to a smelting process for obtaining an intermediate iron product and slag,
• wherein a ratio of slag to intermediate iron product obtained from the smelting process is 0.1 by mass, or higher, and
• introducing one or more flux materials into the smelting furnace in connection with the smelting process so as to adjust slag composition wherein the smelting furnace is an electric furnace of a stationary, non-tilting-type having a holding capacity of between 1000-3000 tonnes iron,
• wherein a combined calcium oxide (CaO), magnesium oxide (MgO) and silica (SiO2) content by mass of the slag obtained from the smelting process exceeds ⅔ of the total contents thereof, and said slag has a basicity above 0.8, and wherein said method further comprises the steps of:
• introducing carbon so as to increase a carbon content of the obtained intermediate iron product to between 1%-4% by mass, and
• introducing the intermediate iron product into a steel conversion unit so as to subject said intermediate iron product to a steel conversion process for reducing a phosphorus content and the carbon content of said intermediate iron product, and to obtain steel having an carbon content of no more than 0.5% by mass
• wherein introducing carbon comprises introducing a carbon containing solid into the smelting furnace in connection with the smelting by feeding said carbon containing solid together with the direct reduced iron, such that said carbon is carried along with the direct reduced iron into a molten bath, and
• wherein the direct reduced iron and the carbon containing solid are stored separately before being introduced into the smelting furnace, and are subsequently introduced into the smelting furnace with a feed tube as a heap above a slag layer.

A method for processing iron ore to obtain steel, the method comprising the steps of:

• introducing iron ore into a gas reduction unit so as to subject said iron ore to a direct reduction process for obtaining direct reduced iron,
• wherein said iron ore comprises:
• a silica (SiO2) content of at least 3% by mass,
• an iron content of no more than 65% by mass, and
• a phosphorus (P2O5) oxide content of at least 0.015% by mass;
• introducing said direct reduced iron into a smelting furnace so as to subject said direct reduced iron to a smelting process for obtaining an intermediate iron product and slag,
• wherein a ratio of slag to intermediate iron product obtained from the smelting process is 0.1 by mass, or higher, and
• introducing one or more flux materials into the smelting furnace in connection with the smelting process so as to adjust slag composition
• wherein the smelting furnace is an electric furnace of a stationary, non-tilting-type,
• wherein a combined calcium oxide (CaO), magnesium oxide (MgO) and silica (SiO2) content by mass of the slag obtained from the smelting process exceeds ⅔ of the total contents thereof, and said slag has a basicity above 0.8, and
• wherein said method further comprises the steps of:
• introducing carbon so as to increase a carbon content of the obtained intermediate iron product to between 1%-4% by mass, by introducing a carbon containing solid into the smelting furnace in connection with the smelting, and
• introducing the intermediate iron product into a steel conversion unit so as to subject said intermediate iron product to a steel conversion process for reducing a phosphorus content and the carbon content of said intermediate iron product, and to obtain steel having an carbon content of no more than 0.5% by mass
• wherein introducing carbon comprises introducing a carbon containing solid into the smelting furnace in connection with the smelting by feeding said carbon containing solid together with the direct reduced iron, such that said carbon is carried along with the direct reduced iron into a molten bath, and
• wherein the direct reduced iron and the carbon containing solid are stored separately before being introduced into the smelting furnace, and are subsequently introduced into the smelting furnace with a feed tube as a heap above a slag layer.

A smelting furnace arrangement for smelting direct reduced iron, so as to obtain an intermediate iron product and slag, comprising a smelting furnace having a rectangular footprint delimited by longitudinally extending lateral walls and end walls extending transversally to the lateral walls,

• wherein the smelting furnace comprises six electrodes arranged in an in-line configuration along a longitudinal direction, the electrodes being arranged centrally in the transverse direction,
• wherein the smelting furnace arrangement comprises:
• at least a dedicated DRI container for holding direct reduced iron,
• a dedicated carbon container for holding a carbon containing solid,
• a common feed tube for introducing both direct reduced iron and carbon containing solid into the smelting furnace as a heap above a slag layer
• wherein a mixer is provided in connection with the common feed tube so as to mix the direct reduced iron and the carbon containing solid prior to being introduced into the furnace, and
• wherein the common feed tube is arranged in a transverse direction between an electrode and the lateral wall.