Assessment of The Beduh Deposits (Lower Triassic) For Lightweight Aggregates, North Amadyia, Kurdistan Region – Iraq
This study deals with the assessment of deposits of the Beduh Formation (Lower Triassic) for lightweight aggregate. It is carried out on channel samples of three exposures (Beduhe, Sararu and Nazdur) at north of Amadyia. Lithologically, the formation consists of alternation of reddish purple, reddish brown and greenish grey shale with subordinate thin sandstone beds and some siltstone streaks. XRD analysis revealed that the studied samples are composed mainly of clay minerals such as illite in major proportion with kaolinite, chlorite, smectite and mixed-layer illite-smectite in minor proportions. The non-clay minerals are quartz and calcite, in major proportions and minor proportions of feldspar and hematite. Grain size analysis showed that the raw materials are composed mainly of clay and silt, with subordinate sand. The plasticity index of these shales is high due to high clay content. Chemical analyses show that the raw materials are composed essentially of silica, alumina, calcium oxide and relatively a less proportion of iron oxide, and appreciable amounts of MgO, K2O, Na2O, TiO2 and MnO. The raw materials are ground and sieved to two sizes: fine size (less than 0.075 mm) and coarse size (less than 1.00 mm). Water is added (about 12-15 %) to the sieved samples and thoroughly mixed, pelletized by hand to lumps named here pellets (about 18-20 mm diameter). The pellets are dried and fired at different temperatures with different soaking times. The evaluation physical tests (bloating, porosity, water absorption and bulk density) shows that the best results achieved through flash firing at 1120°C with soaking time 30 minutes and rapid cooling, after pre-heating to about 300 to 350°C for 10 to 15 minutes. The coarse raw materials (less than 1.00 mm) show better results than the finer size (less than 0.075 mm).
Index Terms- Beduh shale, bloating, flash firing, lightweight aggregate