Refining vessel for high-temperature melt

A refining vessel for high-temperature melt comprising a gas blowing nozzle configured from a refractory for gas blowing nozzle with at least one gas-blowing metal tubule embedded in a carbon-containing refractory,

• the refractory for gas blowing nozzle including a central refractory embedded with the at least one metal tubule, and an outer refractory circumferentially surrounding the central refractory,
• the refractory for gas blowing nozzle having a horizontal projection in which a minimum radius of an imaginary circle encompassing all the metal tubules embedded in the central refractory is R (mm), wherein the central refractory has an outline that falls between one circle that is concentric with the imaginary circle and has a radius of R+10 mm, and another circle that is concentric with the imaginary circle and has a radius of R+150 mm,
• the central refractory is formed of a MgO—C refractory having a carbon content of 30 to 80 mass %, and the outer refractory is formed of a MgO—C refractory having a carbon content of 10 to 25 mass %.