Abstract: Coal gasifiers for the production of reducing gas are protected--at least in parts--by a refractory lining of unburned, carbonaceous magnesia bricks having a carbon content of 5 to 30 percent by weight. The component of these magnesia bricks consisting of sinter and/or fused magnesia suitably has a Fe.sub.2 O.sub.3 content below 6 percent by weight, preferably below 1.5 percent by weight, and a SiO.sub.2 content below 3 percent by weight, preferably below 1 percent by weight.

Abstract: A fired refractory brick composed of magnesia, 2 to 10% alumina, calcium oxide and up to 1.5% silica, the weight ratio of calcium oxide to silica being more than 1.4, and at least 2.2(CaO -1.4 SiO.sub.2)% zirconia, calcium and zirconium forming a calcium zirconate phase in the brick and the content of the calcium zirconate phase being from 0.5 to 8%, all percentages being by weight. This brick is prepared from a mixture of the components by pressing the mixture into the shape of a brick and firing the brick at a temperature of 1600.degree. C to 1800.degree. C until the brick contains the indicated amount of the calcium zirconate phase.

Abstract: A refractory lining for a vessel holding pig iron comprises magnesite-chromite bricks containing from 15-30%, by weight, of chromic oxide. The chromite is so highly dissolved in the brick mass that it has no more than a 12%, by volume, residue of chromite.