The ageing effect of raw materials on the final properties of high alumina refractory grog

High alumina ceramics is a part of the refractory ceramics in SiO 2 -Al 2 O 3 binary system. The aim of this paper is to characterize the effect of ageing raw materials and its influence on final properties of fired refractory grog. Refractory grog is very important component in production of refractory materials, such as fireclay, mullite and andalusite bricks. Refractory grog is manufactured generally from clay, claystone and kaolin, nowadays is mainly burnt in rotary and shaft kilns. The primary objective of this article is to determine an influence of ageing effect, which has impact on mineralogical composition of raw material which obviously results in different mineralogical composition of fired grog. Raw material with different age was used for the mixtures and properties of fired samples were investigated, considering the influence of the raw materials mixtures. Specifically, the apparent porosity, water absorption, bulk density, apparent porosity, mineralogical composition and pore distribution were investigated.