PURPOSE: To improve structural spalling property, joint melting loss property and resistance to abrasion remarkably by improving a resistance to permeability of slag, which has never been resolved by our conventional technique.

CONSTITUTION: A burned magnesia dolomite brick is constituted by adding 0.5-7.0wt.% of fine powder of picrochromite (80wt.% of Cr2O3, 20wt.% of MgO) of 20μm or less to the 100wt.% of refractory material, whose principal constituents are magnesia and dolomite. According to this method, a burned magnesia dolomite brick, obtained by adding 3.0wt.% to a refractory material having the principal constituents of magnesia and dolomite, is reduced by 62.5% in the permeating thickness of slag in the actual use thereof and, as a result, the reduction of speed of melting loss of 41.3% is recognized whereby a large improving effect can be obtained in a resistance to permeability of slag. Further, large effects can be obtained in structural spalling property, a resistance to corrosion and the like due to the reduction of the speed of melting loss.