Open AccessDry separation of brown coal fly ash, determination of its physical, morphological, chemical, and mechanical properties of its cementitious mixes
Author(s) -
Usman Haider,
Z. Bittnar,
Asif Ali,
Lubomír Kopecký,
Vít Šmilauer,
Petr Bittnar,
Jaroslav Pokorný
Publication year - 2017
Publication title -
periodica polytechnica. civil engineering/periodica polytechnica. civil engineering (online)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.406
H-Index - 19
eISSN - 1587-3773
pISSN - 0553-6626
DOI - 10.3311/ppci.9065
Subject(s) - fly ash , materials science , compressive strength , cementitious , composite material , particle size , cement , raw material , scanning electron microscope , coal , mineralogy , chemistry , organic chemistry
The dry separation of brown coal fly ash of density 2.21 g/cm3, specific surface area 5112 cm2/g, having d50 and d97 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.