Permeability of Blast-Furnace Refractories

The permeability of refractories is a governing factor in the deterioration of blast-furnace linings by liquids and gases. Permeability tests there fore were performed on 17 carbon, 11 mullite, 85 castable, and 7 super-duty and 11 high-duty fire-clay brands. The rate of gas flow was measured through a 2-in. cube in three directions by using an improved laboratory permeameter. The range and mean of permeability in centidarcys for each class of refractory were as follows: carbon, 0.3 to 42 (20); mullite, 7 to 158 (48); castable, 0.2 to 43 (4.5); super-duty fire-clay, 28 to 207 (76); and high-duty fire-clay, 33 to 147 (72). The permeability of the different axes of the brick usually varied widely, with the face axis usually exhibiting the lowest values. The improved permeameter should prove to be especially valuable for determining resistance to gas flow and for controlling the quality of refractories.