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 one or more gas-blowing metal tubules embedded in a carbon-containing refractory, the refractory for gas blowing nozzle including a central refractory embedded with the one or more gas-blowing metal tubules, and an outer refractory circumferentially surrounding the central refractory, the refractory for gas blowing nozzle having an operating plane in which a minimum radius of an imaginary circle encompassing all the gas-blowing 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 %,
• wherein the outer refractory has an outline that falls between one circle concentric with the imaginary circle and having a radius of R×2, and another circle concentric with the imaginary circle and having a radius of R×8.