GB727497A - Improvements in or relating to the preparation of metal or silicon carbides - Google Patents

Abstract

Metal or silicon carbides such as those of calcium, aluminium, iron or silicon and a gas containing carbon monoxide with or without hydrogen are simultaneously produced by feeding a mixture of carbonaceous solid fuel and the oxide, hydroxide or carbonate corresponding to the desired carbide to a blast furnace-like generator and blowing into the furnace a gas consisting of at least 50 per cent. by volume of oxygen, the remainder being either or both of steam and carbon dioxide, the proportion of the gas and mixture and the amount of carbon present in the furnace being adjusted in relation to the oxide, hydroxide or carbonate so that when sufficient carbon is burnt to attain carbide-forming temperatures, there will be sufficient remaining unburnt to combine with the oxide, hydroxide or carbonate to form the respective carbide. According to examples, (i) a generator was continuously filled with a charge of 80 parts of coke and 30 parts of limestone, which charge passed through a preheating zone to a furnace hearth where part of the coke was burned with an oxygen-containing blast introduced through a plurality of tuyeres, the blast preheated to 120 DEG C. consisting of 66 per cent. oxygen, 30 per cent. steam and the remainder nitrogen. Raw carbide in a molten state was formed and was discharged from the bottom of the hearth; the gas withdrawn from the top of the generator consisted of 80 per cent. carbon monoxide, 13 per cent. hydrogen and small quantities of nitrogen and carbon dioxide. (ii) A generator was filled with a briquetted charge of coke and lime in the ratio of 4 to 1 by weight and an oxygen blast consisting of technical oxygen and carbon dioxide with a small amount of nitrogen was passed in at 25 DEG C. The raw carbide was withdrawn as in Example (i) and the gas withdrawn from the top of the generator consisted of carbon monoxide with small quantities of nitrogen and carbon dioxide. The oxygen content of the blast may be reduced by 1 per cent. for each 100 DEG C. of preheating. The gas mixture may be employed as starting materials for the methanol-or Fischer-Tropsch-synthesis.