PROBLEM TO BE SOLVED: To provide a lime-based flux for refining capable of considerably enhancing the reactivity by further enhancing the porosity while using a quick lime obtained by baking a limestone, and eliminating the use of a fluorite. SOLUTION: Industrial salt is brought into contact with crushed limestone to perform the salt glaze, and further crushed or pulverized into a salt-glazed quick lime flux. This quick lime flux is reacted with a sulfur component or a phosphoric acid component contained in a molten metal in the metal refining furnace so as to promote the generation of slag. Crushed limestone may be biscuit-fired, and crushed or pulverized biscuit-fired quick lime may be mixed, or crushed limestone may be granulated and mixed with the biscuit-fired quick lime, or calcium/ferrite may be mixed therein. COPYRIGHT: (C)2008,JPO&INPIT