Role of cement content on the properties of self-flowing Al2O3 refractory castables

Study of the hydration of calcium zirconium aluminate (Ca7ZrAl6O18) blended with reactive alumina by calorimetry, thermogravimetry and other methods

“…Nevertheless, several different alternative bonding systems for monolithic refractories have been developed in recent years mainly due to the necessity of the reduction in CaO content and thereby improve cold and hot strength, reduce porosity, increase density and corrosion resistance of castables [6][7][8]. At present, special emphasis is put on the preparation and application of reactive alumina able of forming hydrated phases in water, as an alternative hydraulic binder in unshaped refractory materials [9,10].…”

Preparation of calcium aluminate cement by combustion synthesis and application for corundum‐based castables

“…In recent decades, the castables bonded with calcium aluminate cements (CACs) make up the greatest percentage of monolithics and have been extensively applied in the metallurgical, cement, and chemical industries . With the development in the castables technology, it is necessary to overcome the drawbacks of conventional castables (CCs, 15%‐30% of CACs), such as low hot strengths, abrasion, and corrosion resistance, especially when molten slag and metal are present due to the formation of low‐melting phases (anorthite, gehlenite) in the presence of CaO at elevated temperatures .…”

“…In recent decades, the castables bonded with calcium aluminate cements (CACs) make up the greatest percentage of monolithics and have been extensively applied in the metallurgical, cement, and chemical industries. [1][2][3][4][5] With the development in the castables technology, it is necessary to overcome the drawbacks of conventional castables (CCs, 15%-30% of CACs), such as low hot strengths, abrasion, and corrosion resistance, especially when molten slag and metal are present due to the formation of low-melting phases (anorthite, gehlenite) in the presence of CaO at elevated temperatures. 6,7 And now, one of the approaches used to improve the properties of CCs is to reduce the CAC content in the castables, developing low cement castables (LCCs) and ultra-low cement castables (ULCCs) through adding SiO 2 and Al 2 O 3 micro or ultrafine powders with the aid of deflocculants and similar additives.…”

PREPARATION OF Al₂O₃-CaAl₁₂O₁₉-ZrO₂ COMPOSITE CERAMIC MATERIAL BY THE HYDRATION AND SINTERING OF Ca₇ZrAl₆O₁₈-REACTIVE ALUMINA MIXTURE

“…Because of the high melting temperatures in this system, and due to the hydraulic properties of some calcium aluminates, CACs are successfully used in the corundum refractory castables [5][6]. Among the binary phases in the CaO-Al 2 O 3 system [7], e.g.…”

“…The hydration products of Ca 7 ZrAl 6 O 18 were similar to those formed in the hydration reaction of CACs. In low cement castables (LCCs), the calcium aluminate cement is replaced by hydratable aluminas [6]. This is, the way to reduce the lime content of the refractory concrete. )…”