Solid Phase Combustion of Oxide Systems

M.B.Ismailov, E.E.Dilmukhambetov, S.M.Fomenko

Combustion Problems Institute, 480012, Almaty, 172 Bogenbay Batyr Str., Kazakhstan

Abstract

The physical and chemical bases and macro-kinetic regularities of alumo-thermal solid-phase combustion of oxide systems in conditions of self-propagating high-temperature synthesis (SHS) have been considered. There was shown that the combustion of the most pure oxides is described by simply mathematical model with narrow zone of combustion wave front showing light retardant effects. In combustion of metal oxides of variable valence, as chrome, vanadium etc., the macro-kinetic regularities are determined by chemical stages of reduction process. The alumo-thermal combustion of natural materials, i.e. chromite ores, refractory clays, magnesium minerals, results in formation of refractory products of industrial value. The compositions of exothermal mixtures with alumo-silicate and magnesium minerals making possible the efficiently stable combustion with formation of highly refractory products have been identified.

The obtained results enabled to elaborate new refractory materials as alumo-silicate and magnesium SHS mortars. There is shown that the SHS mortars are superior to ordinary refractory mortars and refractory powders in their physical, mechanical and heat characteristics. The technical characteristics of industrial SHS refractory materials of «Furnon» family and their applications have been specified. Some results of «Furnon» SHS-mortars applications as brickwork mortars in repairs of thermal units showing increase in lining strength by 1.5-2 times have been presented.