To provide a magnesia-spinel brick capable of applying as a refractory for a vacuum degassing furnace, excellent in slaking resistance and hardly causing structural spalling accompanied with slag wetting.
A brick structure is coated with a silica deposited layer by impregnating or coating the magnesia-spinel brick with a colloidal silica solution and then drying to leave, stick and deposit a silica component on the surface and the inside surface of pores of the magnesia-spinel brick. The silica deposited layer plays a role in isolating the brick structure from the contact with the outdoor air and prevents the hydrating reaction of magnesia. Moreover, the silica component deposited on the surface and the pore inside wall of the brick easily reacts with a liquid component entering from outside such as a slag, in the case that the liquid component such as the slag enters into the pores in the course of operating furnace, to increase the viscosity of the liquid component and thus the silica component has an action of preventing the slag or the like from entering further into the inside.
FUKUNAGA TETSUO
INOUE KEIJI
HORI MAKOTO
