In a mixing tank, an upper part of an inner wall in a height direction has a higher surface roughness than a lower part thereof.

Provided are a refractory article, an anti-redox coating composition, and a method of manufacturing the refractory article. The refractory article includes: a platinum(Pt)-based substrate; and a coating layer for preventing a redox reaction on a surface of the Pt-based substrate, wherein the coating layer for preventing a redox reaction includes on an oxide basis SiO2 in an amount of about 40 wt % to about 70 wt %, Al.sub.2O.sub.3 in an amount of about 20 wt % to about 52 wt %, B.sub.2O.sub.3 in an amount of about 3 wt % to about 6 wt %; and CaO in an amount of about 2.4 wt % to about 4.8 wt %.

Provided are a refractory article, an anti-redox coating composition, and a method of manufacturing the refractory article. The refractory article includes: a platinum(Pt)-based substrate; and a coating layer for preventing a redox reaction on a surface of the Pt-based substrate, wherein the coating layer for preventing a redox reaction includes on an oxide basis SiO2 in an amount of about 40 wt % to about 70 wt %, Al.sub.2O.sub.3 in an amount of about 20 wt % to about 52 wt %, B.sub.2O.sub.3 in an amount of about 3 wt % to about 6 wt %; and CaO in an amount of about 2.4 wt % to about 4.8 wt %.