Litologia i właściwości ceramiczne zasiarczonych skał ilastych neokomu z Olszewic (niecka tomaszowska)

Ryszard Wyrwicki

Abstract


 W profilu neokomu Olszewic wydzielono trzy kompleksy litologiczno-surowcowe: I - czarnych, bezwapiennych, piaszczystych mułków kaolinitowo-beidellitowych z glaukonitem i pirytem: II - ciemnoszarych, piaszczystych, wapiennych mułków beidellitowo-illitowych; III - czarnych, ilastych mułków chlorytowo-illitowych, słabo wapnistych, zawierających liczne zooklasty. Pod względem technologicznym skały te reprezentują surowce plastyczne bardzo niskotopliwe, przydatne tylko do produkcji wyrobów czerepie porowatym w bardzo ograniczonym zakresie. Nadmierna zawartość związków siarki częściowo powodujących brak trwałości tworzywa ceramicznego, a częściowo emitowanych do atmosfery jako SO2 czyni surowce nieprzydatnymi dla ceramiki budowlanej.

 

LITHOLOGY AND CERAMIC PROPERTIES OF NEOCOMIAN SULFATED CLAYEY ROCKS FROM OLSZEWICE (TOMASZÓW TROUGH)

 

Ten boreholes were drilled in NW limb of the Tomaszów Trough (Fig. 1). Drillings nos. 2.9 and 10 did not pierce Quaternary deposits up to 15 m below surface while in borehole 1.6 and 7 Albian quartz sands were not encountered to the same depth. Clayey Neocomian rocks were recorded in the remaining four drillings - nos. 3, 4, 5 and 8. The following three lithological-raw material horizons have been recognized in the Neocomian sequence: I black, limeless sandy siltstones containing glauconite and pyrite. II - dark grey, sandy

limy siltstones. III – black, clayey, slightly limy siltstones (Fig. 3). Rock samples from borehole no. 3 were subjected to several analyses i.e. grain size (Tab. 1), chemical (Tab. 2). derivatographical (Tab. 3-6) as well as X-ray one. Due to the results of these analyses the mineral composition or particular complexes has been determined (see Tab. 1). Clay minerals or the 1st complex comprise a beidellite-

kaolinite-illite assemblages, in the IInd complex there is a beidellite-chlorites-illite assemblage and illite-chlorites assemblage has been recorded in the IIIrd complex. In the X-ray analysis plagioclases

manifested in all three complexes, and in the IInd complex potassium feldspar did not exceed 5°.

Technical properties of the clayey rocks are shown in Tab. 3, and the properties of ceramic product kilned of them are shown in Figs. 7-9. They indicate that raw materials have different ceramic properties in each complex. Ceramic product obtained from the 1st complex raw material which had been kilned at the temperature of 850-950°C is not resistant to frost and contains harmful amount of sulfate salts, caused by the considerable admixture of pyrite. The IInd complex raw material yielded ceramic product at t he temperature of 850-1050°C but it is merely freeze resistant. Ceramics deriving from the IIIrd complex expand beginning from the temperature of 950°C. All the above facts cause the limited usefulness of described deposits in production of building ceramics. Their properties are shown in Tab. 4.

Described raw materials contain 2-3° of SO3 and most of it would be emitted to the atmosphere if the exploitation and production of ceramics begun. For this reason the present author suggests neither to consider the clayey deposits of Neocomian as raw material nor to exploit them.


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