In a method for producing a molten steel according to one aspect of the present invention, the solid-state direct reduced iron contains 3.0% by mass or more of SiO.sub.2 and Al.sub.2O.sub.3 in total and 1.0% by mass or more of carbon. A ratio of a metallic iron to the total iron content contained in the solid-state direct reduced iron is 90% by mass or more, and an excess carbon content Cx is 0.2% by mass or more to the carbons contained in the solid-state direct reduced iron. The method includes a step in a first furnace of melting 40 to 100% by mass of the solid-state direct reduced iron, and separating a molten pig iron having a carbon content of 2.0 to 5.0% by mass and a temperature of 1350 to 1550° C. and a slag having a basicity of 1.0 to 1.4 and a step in a second furnace of melting a remainder of the solid reduced iron together with the molten pig iron separated in the first furnace and blowing oxygen onto the molten material to decarburize into a molten steel.

The present disclosure is related to compacted calcium-based granules, in particular pellets, spheroidal/lens-shaped pellets, exhibiting specific chemical and physical properties and comprising a source of calcium and/or a source of magnesium, and optionally one or more additives. The present disclosure further relates to a method for the production of said pellets and to the use of said pellets in, for example, the steel industry, agriculture (in particular precision farming) and the glass industry.

The present invention does not require a demanganese agent such as a sulfide or a combustible gas in the removal of manganese of cast iron. The method for removing manganese of cast iron according to the present invention is implemented by performing the removal of a manganese component by allowing a furnace to be in an oxygen atmosphere, and by blowing air into a molten cast iron in the furnace, while a carbon component in the molten cast iron is being maintained at an approximately constant amount. Alternatively, the method for removing manganese of cast iron according to the present invention is implemented by performing the removal of the manganese component by allowing the furnace to be in an oxygen atmosphere and by stirring the molten cast iron in the furnace, while the carbon component in the molten cast iron is being maintained at an approximately constant amount.

The present invention does not require a demanganese agent such as a sulfide or a combustible gas in the removal of manganese of cast iron. The method for removing manganese of cast iron according to the present invention is implemented by performing the removal of a manganese component by allowing a furnace to be in an oxygen atmosphere, and by blowing air into a molten cast iron in the furnace, while a carbon component in the molten cast iron is being maintained at an approximately constant amount. Alternatively, the method for removing manganese of cast iron according to the present invention is implemented by performing the removal of the manganese component by allowing the furnace to be in an oxygen atmosphere and by stirring the molten cast iron in the furnace, while the carbon component in the molten cast iron is being maintained at an approximately constant amount.

On molten iron having a P concentration of 2 to 4 mass % and having a Cr concentration of 0.3 to 1.2 mass %, a dechromization treatment is performed by adjusting a basicity (CaO mass %)/(SiO.sub.2 mass %) of slag to greater than 0.1 and 1 or less and supplying an oxygen source with a molten iron temperature falling within a range of 1250 to 1500° C. to manufacture molten iron having a P concentration of 1.9 to 3.8 mass % and having a Cr concentration of less than 0.2 mass %.

On molten iron having a P concentration of 2 to 4 mass % and having a Cr concentration of 0.3 to 1.2 mass %, a dechromization treatment is performed by adjusting a basicity (CaO mass %)/(SiO.sub.2 mass %) of slag to greater than 0.1 and 1 or less and supplying an oxygen source with a molten iron temperature falling within a range of 1250 to 1500° C. to manufacture molten iron having a P concentration of 1.9 to 3.8 mass % and having a Cr concentration of less than 0.2 mass %.

A method for ironmaking by smelting reduction in a stir-generated vortex includes: (1) placing a pig iron in an induction furnace, and then heating the pig iron to a molten state to form a molten iron, and maintaining the molten iron to be greater than or equal to 1450° C.; (2) stirring a center of the molten iron to form a vortex with a height-to-diameter ratio of 0.5-2.5, and continuously performing stirring; (3) mixing and grinding on an iron-containing mineral, a reducing agent and a slag-forming agent in a mass ratio of 1:(0.1-0.15):(0.25-0.4) to obtain a powder mixture, spraying and blowing the powder mixture to a center of the vortex, performing a reduction reaction, and stopping the stirring after the molten iron and molten slags are obtained, wherein a waste gas is produced; and (4) discharging the molten iron and the molten slags respectively, and exhausting a treated waste gas.

A method for ironmaking by smelting reduction in a stir-generated vortex includes: (1) placing a pig iron in an induction furnace, and then heating the pig iron to a molten state to form a molten iron, and maintaining the molten iron to be greater than or equal to 1450° C.; (2) stirring a center of the molten iron to form a vortex with a height-to-diameter ratio of 0.5-2.5, and continuously performing stirring; (3) mixing and grinding on an iron-containing mineral, a reducing agent and a slag-forming agent in a mass ratio of 1:(0.1-0.15):(0.25-0.4) to obtain a powder mixture, spraying and blowing the powder mixture to a center of the vortex, performing a reduction reaction, and stopping the stirring after the molten iron and molten slags are obtained, wherein a waste gas is produced; and (4) discharging the molten iron and the molten slags respectively, and exhausting a treated waste gas.

Various embodiments include processes for purifying and/or preparing iron-bearing materials. Various embodiments include purification and/or preparation of iron ores, iron, and their intermediates. Various embodiments include processes for purifying iron-bearing materials comprising leaching one or more soluble species of impurities out of iron-bearing materials using a leaching solution comprising fluorine.

Various embodiments include processes for purifying and/or preparing iron-bearing materials. Various embodiments include purification and/or preparation of iron ores, iron, and their intermediates. Various embodiments include processes for purifying iron-bearing materials comprising leaching one or more soluble species of impurities out of iron-bearing materials using a leaching solution comprising fluorine.