Issue No. 1

Abstract

Al₂O₃-MgO spinel castable consisting of 70% Al₂O₃ and 30% MgO was synthesized using raw materials like fused alumina and dead burnt magnesia of different grain sizes. Co-precipitated aluminium hydroxide and magnesium hydroxide gel were used as binder of the castable. Role of TiO₂ additives in different proportions on the densification behaviour of such castable was assessed through the measurement of parameters like bulk density, volume shrinkage, apparent porosity, specific gravity and the microstructure was evaluated by SEM and XRD studies. It was observed that TiO₂ exhibited positive influence on the densification behaviour of these compacts.

Abstract

Porous ceramic building materials produced from illite clays with organic and inorganic additives are investigated. The raw materials used are: Devonian limeless and Quaternary lime rich clays of Latvia and the additive - fine saw dust, wood grinding dust, limestone powder and chamotte made from Devonian clay. Pore distribution is investigated and Maage index is calculated from the analyses of frost resistance. From the results of these analyses it is established that for investigated materials is necessary to provide hightened enhanced Maage index. This conclusion follows from the fact that the dominant pore size has to be above 1m. Firing of illite containing limeless clays with additive at temperature 980-1000 °C and lime rich clays with additive at temperature 1000-1020 °C allows to achieve this pore structure.

Abstract

The analysis of gas emissions while firing gives basic information for the best management of the firing process, to achieve a product with fewer faults and better features, while optimizing at the same time the firing cycle according to the features of the body to be fired.