Refractory castables based on barium aluminate cements

Abstract

In this study the results of the structure, shrinkage and physical and mechanical properties of concrete obtained from dry mixes on the base of aluminate cements for self-leveling floors are presented. Principle possibility of obtaining unshrinkable concretes with the formation of ettringite using aluminate cement, gypsum and modern superplasticizers. Studies of free shrinkage of mixed binder showed that binder can be attribute to binders with compensated shrinkage. Cracking resistance of the composition is provided by the fact that the vast expansion in the initial stage of curing and shrinkage of the final stage is in 5...10 times lower than these values for gypsum and portland cement.

The crystal structure of Na2CaAl4O8 and its hydration behaviour

“…impure synthetic alumina) can also be used as alternative starting raw materials [1]. Currently, the use of alternative raw materials with a wide range of chemical composition and origins, such as laterite, iron-rich bauxite, lowgrade alumina and blast furnace slags, appears the most challenging frontier in CACs manufacturing due to the limited supply of bauxite [8,9]. Nevertheless, these alternative raw materials always introduce minor and trace elements (i.e., manganese, titanium, copper, nickel, alkali elements, fluorine and chlorine) that could affect positively or adversely the cement manufacturing and the cement properties, as broadly investigated in Ordinary Portland Clinker (OPC) [10,11,12,13,14,15,16].…”

An insight on the effect of sodium and silicon on microstructure and crystallography of high alumina cements

“…laterite, iron-rich bauxite, low grade alumina, blast furnace slags, Al-rich wastes, etc.) appears the most challenging frontier in CACs manufacture handling: (i) the shortage of bauxite deposits; (iii) the high energy demanding process of synthetic alumina production [8,9], which also requires to use several chemical compounds [20,73]; (iii) the dangerous wastes coming from aluminium industries, such as Al-anodizing waste [74], Al-slag (dross) [72,74] and gas cleaning dust from Al-electrolysis plants [74], which cause many ecological and healthy problems and have high treatment costs [71]. However, the alternative raw materials commonly introduce minor elements (i.e.…”

Effect of High‐Energy Ball Milling and Silica Fume Addition inBaCO3–Al2O3. Part I: Formation of Cementing Phases

“…Applications of these types of castables are limited to 1800°C . Beyond this temperature barium aluminate cement (BAC) has proven more reliable cement for the formation of refractory concretes with better chemical and mechanical properties . BAC has higher refractoriness than CAC with similar cementing properties .…”