Process for producing bodies of refractory material

Claim 1

A PROCESS FOR PRODUCING A BODY OF REFRACTORY MATERIAL RESISTANT TO THERMAL STRESSES, COMPRISING THE STEPS OF: SHAPING A MASS ENTIRELY COMPOSED OF INORGANIC PARTICLES, CONSISTING IN MAJOR PART OF AT LEAST ONE CERAMIC MATERIAL SELECTED FROM THE GROUP WHICH CONSISTS OF MAGNESIA AND ALUMINA, INTO A POROUS BODY OF THE CONFIGURATION TO BE PRODUCED; HOLDING SAID PARTICLES TOGETHER BY PRELIMINARY SINTERING WHILE MAINTAINING THE POROSITY OF SAID BODY IMPREGNATING SAID BODY WITH AT LEAST ONE BITUMINOUS HYDROCARBON THERMALLY DECOMPOSABLE AT A TEMPERATURE ABOVE ABOUT 300*C. INTO ELEMENTAL CARBON; HEATING THE IMPREGNATED BODY IN A CLOSED CHAMBER UNDER AN INERT-GAS PRESSURE TO A TEMPERATURE LESS THAN SUBSTANTIALLY 1000*C. BUT SUFFICIENT TO CAUSE AT LEAST PARTIAL DECOMPOSITION OF SAID HYDROCARBON TO PRODUCE A RESIDUE OF ELEMENTAL CARBON SUBSTANTIALLY FILLING SAID BODY BETWEEN THE INTERSTICES OF SAID PARTICLES OF CERAMIC MATERIAL; AND MAINTAINING THE GAS PRESSURE IN SAID CHAMBER AT A LEVEL UPWARDS OF ABOUT 5 ATMOSPHERES THROUGHOUT THE HEATING STEP.