TY - JOUR AU - Haider, Usman AU - Bittnar, Zdeněk AU - Ali, Asif AU - Kopecky, Lubomír AU - Šmilauer, Vít AU - Bittnar, Petr AU - Pokorny, Jaroslav PY - 2017/01/01 Y2 - 2024/03/29 TI - Dry Separation of Brown Coal Fly Ash, Determination of Properties of Separated Parts, and Their Application in High Volume Cementitious Pastes JF - Periodica Polytechnica Civil Engineering JA - Period. Polytech. Civil Eng. VL - 61 IS - 3 SE - Research Article DO - 10.3311/PPci.9065 UR - https://pp.bme.hu/ci/article/view/9065 SP - 590-601 AB - <p>The dry separation of brown coal fly ash of density 2.21 g/cm<sup>3</sup>, specific surface area 5112 cm<sup>2</sup>/g, having d<sub>50</sub> and d<sub>97</sub> of 60 and 231 µm was carried out in this research using ultrafine air classifier. Classifiers wheel speed was increased from 2000 to 10000 rpm to obtain fine and coarse products. Median diameter of 5.62 µm was obtained for fine products at a speed of 10000 rpm with nearly 90% decrease in median particle size as compared raw fly ash. Particle morphology was observed on optical, electron microscopes which showed that at 10000 rpm classifiers wheel speed, average fine particles morphology changed from angular and rounded slaggy particles to spherical particles. Cement – 60% fine products samples showed an increase of 26% of compressive strength at 90 days as compared to raw fly ash and linear relationship was developed between median diameter of fines and compressive strength.</p> ER -