Surowce ilaste południowej części Ziemi Lubuskiej

Abstract

Podsumowano wyniki badań mio-plioceńskich (seria poznańska) i górno plioceńskich (seria Gozdnicy) surowców ilastych południowej części Ziemi Lubuskiej.Przedstawiono geologiczne warunki występowania złóż oraz skład mineralny i podstawowe własności ceramiczne surowców zarówno w przekroju stratygraficznym, jak też w aspekcie regionalnym, a szczególnie w nawiązaniu do obszarów zaburzonych i nie zaburzonych glacitektonicznie. Uwypuklono przy tym własności technologiczne wyróżnionych odmian, tj. surowców beidelitowych oraz kaolinitowych, jak również własności fizyczne uzyskanych z nich tworzyw ceramicznych. CLAY RAW MATERIALS IN SOUTHERN PART OF THE ZIEMIA LUBUSKAIn the Ziemia Lubuska (south-western Poland), clay raw materials mainly occur in Upper Miocene and Lower Pilocene deposits assigned to the Poznań series and, to a same degree, in the Upper Pliocene Gozdnica series.Three horizons differing in lithological development, ratios of mineral components and genesis are differentiated in the Poznan series. Deposits of clay raw materials are primarily related to the upper and some parts of the lower horizons which are characterized by predominance of mottled and green clays, respectively.In areas of strong glacitectonic disturbances (i. e. in areas of fold-type deformations, with amplitude of 100 m or more), the deposits comprise various parts of the profile of this series or, when strata are steeply dipping, the whole profile attaining several tens of meters in thickness.In the Gozdnica series, clays are intercalating sandy-gravel deposits. They form lenticular layers usually attaining up to a few meters in thickness.Raw materials are termed as beidellite or kaolinite after quantitatively predominating component (Tab. 1). Beidellite raw materials mainly occur in the middle (green clays) as well as the upper (mottled clays) horizon of the Poznan series whereas the kaolinite raw materials predominate in the Gozdnica series and the lower (grey clays) horizon of the Poznan series. The latter are also found in some places in the mottled clay horizon where they form a facies variety of otherwise omnipresent beidellite clays.Beidellite raw materials are more plastic and shrinkable due to drying (Tab. 2) and capable to adsorb larger quantities of water than kaolinite raw materials with the same content of clay minerals.The temperature of maximum sintering of beidellite raw materials ranges from 1050 to 1250°C and mainly from 1100 to 1150°C, and that of kaolinite raw materials – from 1100 to 1300°C and mainly from 1200 to 1250°C. The temperature of onset of sintering (when water absorption is 6%) is also different, ranging from 980 to 1170°C and most often from 1030 to 1100°C for beidellite raw materials and from 1000 to 1250°C and most often from 1070 to 1140°C for the kaolinite ones.The sintering interval is 25 – 150°C and mainly 60 – 120°C for the bulk of beidellite raw materials and 50 – 160°C for kaolinite raw materials as a whole and 100 – 150°C for the bulk of them.Beidellite raw materials swell thermically in temperatures higher than that of the maximum sintering. This process is most intense in the case of the materials from green clay horizon and, to a certain degree, those from the flame clay horizon. The kaolinite raw materials swell very weakly if ever in the temperature range up to 1300°C.Figures 2 – 8, and 13 – 16 show physical properties of ceramic material from firing of various varietes of beidellite raw materials and Figures 9, 11, 12, 17 and 18 – of material obtained from firing of kaolinite raw materials.