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.

Abstract: A method is provided for the production of magnesium oxide -- chromic oxide wherein magnesium chromite of about 3 to 82 weight percent Cr.sub.2 O.sub.3 is mixed with 0.05 to 4 weight percent of CaO or SrO and sintering the mixture at a temperature above about 1750.degree. C.