Fundamentals of the technology of ceramoconcrete

Abstract

Refractory concretes, ramming compounds, and large refractory blocks are used for the construction of the lining of the heat-using equipment of the metallurgical industry [1; 2, pp. 462-474; 3; 4]. The main adverse characteristics of these materials are inadequate density, loss of strength over a given temperature range, inadequate volumetric stability, the interaction of the binder and filler, loss of refractoriness due to the presence of a binder substance, etc. These Shortcomings can be partly overcome by the use of ceramoconcretes which are heterogeneous polyfractional compositions consisting of a coarse-grained refractory aggregate (50-80 vol. %) the space between the grains being filled with a dispersed ceramic bond ("binder") to give a strong conglomerate. The texture of these materials is "concrete-like~ owing to the "ceramic reinforcement." The aggregate and binder can be of the same or dissimilar nature (i. e., chemical composition and structure).

Structure-Mechanical Properties of Plasticized Mixes Based on Highly Concentrated Ceramic Binding Suspensions (HCBS) of High-Alumina Chamotte

“…It should be noted that press-molded specimens with low porosity (14 -15%, dried at 110°C; see Figure 11a, curve 4 ) could not be obtained using P sp = 200 -500 MPa [4,10]. The mixes exhibited high mechanical strength, both as green preforms and heat-treated products.…”

“…The relation between the volume fraction of liquid in the system and porosity of the pressure-molded specimen was discussed in [10, p. 352]. For mixes of different composition (curves 1 -3 ), the process of compaction exhibits the usual behavior [6,10]. In mixes with low values of m b (mass fraction of the binder), the porosity P op was found to be 18.7 and 16% for m b = 30 and 35%, respectively (at P sp = 10 MPa).…”

Nanodisperse silica and some aspects of nanotechnologies in the field of silicate materials science. Part 2

“…The minimum size d min of HCBS particles amounts tõ 5 -10 nm (nanoparticles), whereas the maximum size d max attains 100 -200 mm for HCBS used in the technology of quartz ceramics [7,35] and 300 -400 mm in the technology of quartz refractories [27,36]. In this connection, objective difficulties arise in the study of the fully disperse composition of solid-phase particles in such systems.…”

“…11) is the introduction of effective deflocculating agents (liquefiers) and intense mixing. If we take into account the general concepts of rheology and colloid chemistry [36], the efficiency of introduction of MS will be explainable by redistribution of the dispersion medium C W in the molding system. The state describable by the diagram presented in Fig.…”

“…The filler ensures only 1 -2% of the specific surface of the solid phase. The corresponding role in the formation of properties of materials based on HCBS (quartz ceramics) and ceramic concretes is played by the reactive colloid component (nanoparticles).The minimum size d min of HCBS particles amounts tõ 5 -10 nm (nanoparticles), whereas the maximum size d max attains 100 -200 mm for HCBS used in the technology of quartz ceramics [7,35] and 300 -400 mm in the technology of quartz refractories [27,36]. In this connection, objective difficulties arise in the study of the fully disperse composition of solid-phase particles in such systems.…”