CGL-POT is a container for molten zinc or zinc alloy, and mainly used as an equipment in which galvanized steel sheet is manufactured by passing hot-coil therein. Zinc and zinc alloy have relatively low melting points (approximately around 420 ℃), thus the operation is being done under the temperature from 450 to 700 ℃; however there is a high possibility that a molten metal may adhere to the surface of refractories, and/or a molten metal may permeate through the air holes on the surface of refractories.

Moreover, penetrated zinc or other nonferrous metal often causes a chemical change of refractories, and this change usually results in drastic decrease of its functionality. Therefore, it is being required that the refractories for CGL-POT should have a high quality which can reduce the adhesiveness of molten zinc, zinc alloy, and aluminium against to the refractories and also the chemical reaction between those in order to maximize economic feasibility of POT.