Method for removing phosphorus from phosphorus-containing substance, method for manufacturing raw material for metal smelting or raw material for metal refining, and method for manufacturing metal

A method for removing phosphorus from a phosphorus-containing substance, the method comprising:

• reacting the phosphorus-containing substance that is used as a raw material for metal smelting or metal refining with a nitrogen-containing gas so that phosphorus in the phosphorus-containing substance is removed through nitriding, and
• prior to the nitriding removal of phosphorus from the phosphorus-containing substance, performing a reduction treatment in which the phosphorus-containing substance is heated to an unmolten state temperature range so as to react with a reducing agent, thereby reducing a part of metal oxide in the phosphorus-containing substance,
• wherein:
• the reducing agent is a reducing gas or a solid reducing agent;
• and
• the reduction treatment using the reducing gas is performed in a range of Expression (2) below:
• [Expression 2]
• 1.5≤x×Q≤6.0 (2)
• wherein x denotes twice (-) a volume ratio of an oxygen gas in a standard state required for complete combustion of a unit volume of the reducing gas in the standard state, and Q denotes an amount of the reducing gas (Nm3/kg) used for the reduction treatment with respect to a total amount of iron oxide and manganese oxide in the phosphorus-containing substance.