Własności ceramiczne ilastych osadów neogenu niecki orawsko-nowotarskiej

Abstract

 W nawiązaniu do składu mineralnego określono własności technologiczne oraz własności tworzywa ceramicznego uzyskanego z bezwapiennych osadów formacji iłów lignitowych i osadów wapnistych warstw Domańskiego Wierchu. Mułki piaszczyste formacji iłów lignitowych nie mają cech samoistnego surowca, mułki mogą być przydatne do produkcji grubościennych wyrobów porowatych lub spieczonych, ilaste mułki lignitowe – do produkcji grubościennych wyrobów porowatych, iły piaszczyste do produkcji grubo- i cienkościennych wyrobów porowatych oraz iły lignitowe – do produkcji tych samych, lecz o większej porowatości, lub do produkcji keramzytu. Wapnistość i częściowe zamarglenie ograniczają przydatność różnych odmian mułków i iłów warstw Domańskiego Wierchu tylko do produkcji wyrobów grubościennych o czerepie porowatym. CERAMIC PROPERTIES OF NEOGENE CLAY DEPOSITS FROM THE ORAWA-NOWY TARG BASIN The paper deals with noncalcareous clay deposits of the Lignite Clay Formation and some younger, weakly calcareous clays and silts of the Domański Wierch Beds, occurring in the Orawa–Nowy TargBasin (southern Poland). The deposits display some features of raw material for production of building ceramics.Deposits of the Lignite Clay Formation (Table 1) yield 25–55% of clay minerals, 10–70% of quartz grains varying in size, and 0.5–15 % of organic matter. Beidellite is the major clay mineral here, quantitatively predominating over chlorite and illite. Five raw material complexes differing in mineral composition and ceramic properties were distinguished in that formation.Lignite clays (sample 1) yield 50–55% of clay minerals and 10–15% of organic matter. They represent a plastic raw material, usable in production of thin-walled, porous and highly absorbing products (Fig. 1) or, at temperatures over 1100°C, light ceramic aggregates – ceramsite.Silts (sample 2) yield 35–40% of clay minerals and 2–3% of organic matter. They represent medium-plastic raw material, usable in production of thick-walled porous products or caked ones (e.g. building clinker, depending on temperature of kilning (Fig. 2).Sandy silts (sample 3) yield only 25–30% of clay minerals and 0.5% of organic matter. They represent raw material suitable for reducing plasticity of plastic clays only.Sandy clays (sample 9) yield 50–55% of clay minerals and 2.5% of organic matter. They represent plastic raw material usable in production of thin-walled porous products only (Fig. 4).Lignite clay silts (sample 10) yield 40–45% of clay minerals and 4–5% of organic matter. They represent raw material usable for production of low-class thick-walled products (Fig. 5).Table 2 shows technological properties of the above raw materials and Table 2 – the range of variability of physical properties of ceramic products.Clay deposits of the Domański Wierch Beds are more diversified in mineral composition. They yield 35–55% of clay minerals, 32–54% of quartz, mainly very fine-grained, 4.8–10.9% of calcite, and 0.3–1.4 % of organic matter, 0–7% of goethite, 0–5% of siderite, and sometimes pyrite and dolomite (Table 4). Clay minerals are represented by beidellite, chlorite and illite, occurring in varying proportions. The deposits also yield marly nodules (0.44 to 2.08 weight %, see Fig. 6A) bearing negative effect on ceramic material, and siderite (Fig. 6B) and siderite-dolomite-marly (Fig. 6C) nodules.Six lithological varieties of ceramic raw materials were distinguished in the Domański Wierch Beds: clays (sample 11), clay silts (samples 12, 15 and 16), silts (sample 13) and calcareous silts (sample 14). The presence of calcite makes these raw material very easy to melt – temperature of melting ranges from 1160 to 1230°C. The materials are characterized by wide interval (l50–255°C) in which porous products are obtained, and very narrow (from 10 to 50°C) interval of kilning (Table 7). They belong to medium-plastic and plastic raw materials and – as it follows from kilning curves (Figs 7–12) they are usable for production of thick-walled products only. Temperature of kilning of these products cannot be lower than 1000°C as the material kilned at 850–950°C is damaged by nodules