Unfired, refractory, basic bricks and compositions and their method of manufacture

Abstract

Unfired, refractory compositions are provided containing a refractory material of magnesia, dolomite, lime or mixtures thereof, a carbonaceous binder, and elementary carbon. The amount of elementary carbon incorporated in the composition is controlled and depends on the amount of Fe.sub.2 O.sub.3 present in the refractory material. The compositions are provided with at most 1.5% elementary carbon if the Fe.sub.2 O.sub.3 content is below 0.5%; at most 1.75% elementary carbon if the Fe.sub.2 O.sub.3 content is 0.5 to 2.5%, at most 2.0% elementary carbon if the Fe.sub.2 O.sub.3 content is above 2.5 to 4.5%, and at most 2.5% elementary carbon if the Fe.sub.2 O.sub.3 content is above 4.5%. Refractory shapes and bricks produced from these refractory compositions where the amount of elementary carbon is controlled according to the Fe.sub.2 O.sub.3 content of the refractory material show an increased durability over similar refractory shapes and bricks where the elementary carbon addition is not made or where it is made in excess of the above critical amounts without regard to the Fe.sub.2 O.sub.3 content.

Dependencies are inferred from the claim text.