Gliny ceramiczne i ogniotrwałe w świetle badań mineralogicznych

Abstract

CERAMIC AND REFRACTORY CLAYS IN THE LIGHT OF MINERALOGICAL INVESTIGATIONS Summary The article presents results of mineralogical investigations of refractory clays, as well as of white burning ceramic clays used in production of faience, porcellite and stoneware. The most important clay deposits of such a type occur in the Miocene formations, in the region of Strzegom and Zgorzelec, Lower Silesia, in the Santonian formations, near Bolesławiec, and in the Rhaetic-Liassic formations of the Holy Cross Mts, as well as in the Liassic ones, in the vicinities of Krzeszowice. A high kaolinite content in clays of the Strzegom and Zgorzelec regions proves their technological properties as high-refractory ones (up to 177 sP); moreover, they are easily sintering (1200°) and plastic, being characteristic of great contractility when drying and burning. Deposits occurring in the vicinities of Bolesławiec belong to the white burning clays. These clays contain less kaolinite, considerable quantity of micas, i.e. factors Influencing upon decrease of their refractoriness (165-171 sP). These are lean clays of sintering temperature amounting about 1300°. As concerns mineral composition and grain-size, the clays from the Krzeszowice vicinities are similar to these from the Holy Cross Mts. They are plastic clays, in general, their refractoriness does not exceed 171 sP, and sintering temperature is 1250-1300°C. The results of investigations on mineral composition of clay deposits served for establishing the stratigraphical correlation of these deposits.