O własnościach ogniotrwałych piaskowców kredowych niecki śródsudeckiej

Abstract

ON PROPERTIES OF CRETACEOUS REFRACTORY SANDSTONES OF THE INTRA-SUDETIC TROUGHSummaryThe paper deals with the results of the research on the possibility of applying the Emscherian quartz sandstones (from the area of the Intra-Sudetic trough) as unfired refractory materials. These sandstones may be used, as especially dressed blocks, in construction of glass-furnaces.The sandstones under consideration distinguish themselves in having about 97.5–98,6% of SiO2, in small amounts of siliceous cement with clay admixture, as well as in a generally uniform granulometric composition. The results of chemical analysis of the samples examined are presented in Table I, those of granulometric composition – in Table 2, and the results of planimetric analyses – in Table 3.The large amount of SiO2 is responsible for the high refractoriness and for the softening temperature under load of sandstones, as it may be seen from the data shown in Table 4. After burning, made under both laboratory and industrial conditions, the sandstone samples consist mainly of unchanged grains of quartz and cristobalite b. The presence of the latter one has been proved by the absorption spectrophotometry method in infra-red radiation (Fig. 1). The formation of the cristolbalite was conditioned by the almost monomineral nature of the rock, and by the lack of proper mineralizers. Of particular importance for the problem here considered are both physical and technical properties of the sandstones after buring. Appropriate data may be found Tables 5 and 6. It results from these tables that after burning the sandstones reveal a relatively slight increase in porosity, and a low linear expansion. Their compressive strength has also been presented.