Study On The Properties And Microstructure Of ZrO₂ Composite MgO-CaO Materials

The effects of adding quantities and types of ZrO₂ on properties and microstructure of synthetic MgO-CaO clinker and MgO-CaO bricks have been studied by phase diagram, XRD, microscope, SEM, etc. The results show that:Introducing ZrO₂ into the composites can promote sintering. The bulk density increases with the increasing of ZrO₂ content. There are amount of direct bonding between periclase, lime and calcium zirconate (CaZrO₃) in the composites. However the structure of the composites become porous when the content of ZrO₂ is higher. The bulk density of the composites decreases with the increasing of ZrSiO₄ content.When ZrO₂ or ZrSiO₄ is added to MgO-CaO bricks in the composites, the thermal shock resistance and slag resistance of the bricks improved obviously. However the bricks exhibits worse sinter-ability at 1600℃temperature, and the cold properties and hydration resistance of the bricks are not improved. When ZrO₂ is added to the bricks in fine powder, the values of cold properties, hydration resistance, thermal shock resistance and slag resistances increase. When ZrO₂ content is 2%～7%, the bricks show superior cold properties. When the content is added to 5%, the hydration resistance of the bricks is better. The thermal shock resistance of the bricks is excellent with the content of ZrO₂ 10%～15%. ZrSiO₄ which is added to the bricks in fine powder can improve the hydration resistance and thermal shock resistance of the bricks obviously. The bricks show superior hydration resistance and thermal shock resistance with the content of ZrSiO₄ 5%. But the bulk density, strength and slag resistances of the bricks decrease with the increasing of ZrSiO₄ content. When ZrSiO₄ content is more than 10%, the bricks are porous and cracky numerously.