Causes and mechanism of destruction of heat-resistant concrete in an aggressive reducing gas environment of carbon monoxide at high temperatures

摘要

Scientific and technological progress in a number of industries has led to the need to create new types of thermal aggregates in which high-temperature production processes occur in the presence of highly aggressive media towards lining materials.The medium with a high concentration of carbon monoxide(CO)reducing gas can be considered as an example.For the lining of such thermal aggregates in practice,special piece refractory were used,therefore,the available literature data on the resistance of materials under these conditions are mainly related to them,and for fundamentally different heat-resistant concretes this question is not well studied.It should be noted that heat-resistant concrete is a relatively new type of lining material,which has proven high technical and economic efficiency of use.They are non fired materials,the stabilization of the structure and properties of which occurs during drying and first heating of the structures,which are made from the latter-directly in the constructed thermal aggregate.In view of the circumstances,in comparison with pre-fired refractory items,have a number of features,and question arose on the way to creating similar heat-resistant concrete,which require thorough studies.A variety of heat-resistant aggregates,binders and concrete on their base with different chemical and mineralogical compositions,structures and physical and mechanical properties were studied through various laboratory tests.As a result of physical and mechanical,physical and chemical and electron-microscopic complex studies,the causes and the mechanism of their destruction in these conditions are identified and all the initial requirements for the components and technologies for preparing and using such concretes are established.The correctness of the established criteria is proved by the long-term reliable operation of lightweight heat-corrosion-resistant perlite concrete,developed on high-alumina cements in monolithic linings of a number of thermal aggregates of Oskol Electrometallurgical Plant of the Russian Federation.In the presented article,only part of the results is presented,which relates to the causes and mechanisms of destruction of heat-resistant concrete in afore-mentioned conditions.