PERICLASE-SPINEL REFRACTORY MODIFIED ТІО2

Over the past decades, the development and improvement of refractory materials for lining high-temperature zones of rotary kilns continues. The main requirements for refractory products for lining rotary kilns for cement clinker roasting are: high density and ultimate compressive strength, low porosity and gas permeability, increased abrasion resistance, low thermal conductivity, high corrosion resistance and the ability to form a protective layer.Today, the main goal of modern researchers is to create a heat-resistant refractory with a flexible structure that ensures its integrity at high temperatures and mechanical loads, which have the ability to form a protective coating layer. In this work, a technological approach has been tested for introducing a vibro-milled modifier (briquette based on a high-alumina component and a titanium-containing additive) into the composition of the raw charge for periclase-spinel refractory in the form of a pre-synthesized product containing crystalline phases of the Al2O3 – TiO2 – FeO system. The basis for the production of periclase-spinel refractories modified with TiO2 is the four-component system MgO – Al2O3 – FeO – TiO2, on the basis of thermodynamic calculations of which the content of individual components of the charge was selected and the operational characteristics were predicted. The interrelation of physical and mechanical properties with the content of individual components in the initial charge warehouses is shown, and the directions of solid-phase processes with their participation are noted. The features of the microstructure of the sample material are noted in relation to the formation of an optimal set of properties. It is shown that the nature of the organization of micropores is favorable for increasing the thermal stability of the material, which complements the phase adaptation mechanism also with the structural effect of damping mechanical stresses during thermal cycling.

Optimization of Properties for Alumina-Spinel Refractory Castables by CMA (CaO-MgO-Al2O3) Aggregates

Aiming at optimizing properties of alumina-spinel refractory castables, coarse corundum particles were replaced partially with the particles of a novel porous multi-component CMA (CaO-MgO-Al2O3) aggregate in the same size. Properties including the bulk density, apparent porosity, strength, slag corrosion resistance, thermal shock resistance and thermal fatigue resistance of alumina-spinel refractory castables containing CMA aggregates were evaluated contrastively. The results demonstrated that the incorporation of CMA aggregates can significantly improve thermal shock resistance and thermal fatigue resistance of castables, although companying with slight decrease in the bulk density and strength. Moreover, slag penetration resistance of castables can also be enhanced by CMA aggregates with appropriate particle size. The influence of CMA aggregates on properties of alumina-spinel refractory castables depended strongly on their particle size.