Refractory bricks, blocks, tiles and similar refractory ceramic constructional goods containing, by weight, > 7% but < 45% alumina, but > 50% by weight combined with silica
Refractory bricks, blocks, tiles and similar refractory ceramic constructional goods containing, by weight, > 50% alumina, silica or a mixture or compound of these products (excl. containing, by weight, > 93% silica, > 7% but < 45% alumina and those of siliceous fossil meals or similar siliceous earths)