Ceramics-Silikáty 40, (4) 149 - 159 (1996)

The present criteria which basaltoids for petrurgical* purposes should meet are generally regarded as being associated with the qualitative and quantitative parameters of their chemical and mineralogical composition. However, in petrurgical practice one can observe the phenomenon that rocks with virtually identical compositions show variable technological properties during the melting and subsequent processing. This is also the case of alkaline olivine basalt and nepheline basanite from the Bíleice locality (12 km SE of Bruntál) used in the manufacture of rockwool. This variability of petrurgic properties, shown in spite of a relatively very stable chemical and mineralogical composition of the raw material, was the reason why the rocks were subject to a detailed petrographic and geochemical study. This study resulted in the finding that in assessing the raw materials for petrurgical processing according to their chemical and mineralogical composition, attention should also be paid to the textural and structural characteristics of the respective rocks.