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Mineral melting behavior of chinese blended coal ash under gasification condition
Author(s) -
Wu Xiaojiang,
Zhou Tuo,
Chen Yushuang,
Zhang Zhongxiao,
Piao Guilin,
Kobayashi Nobusuke,
Mori Shigekatsu,
Itaya Yoshinori
Publication year - 2011
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.425
Subject(s) - anorthite , gehlenite , mullite , fly ash , albite , mineralogy , melilite , materials science , nepheline , geology , metallurgy , quartz , chemistry , phase (matter) , composite material , ceramic , spinel , organic chemistry
The fusibility and mineral melting behavior of Chinese blended coal ash under gasification condition were studied by standard ash fusion temperature (AFT) test, X‐ray diffraction (XRD), scanning electron microscope (SEM) and phase diagram theory. The experimental results show that the trend of blended ash's AFT is not linearly related to the blending ratios, but mirrors by changes in liquidus temperature from ternary phase diagram systems. The AFTs of those blended ashes whose main ash chemical compositions locate near the boundaries between two mineral regions or triple points are lower and change more evident than that of those blended ashes whose main ash chemical compositions are far away from the boundaries or triple points. With increasing mass fraction of low AFT ash in blended coal ash, the location of blended ash in ternary systems is changed from the mullite region to the anorthite region, as well as the dominant crystal mineral at deformation temperature (DT) is also transformed from mullite to anorthite via mullite–mullite and anorthite coexisting–anorthite. The fluxing minerals (anhydrite, wustite, albite, hercynite, augite) in low AFT ash can react with the refractory minerals (mullite, quartz) complicatedly to form new low‐melting minerals (anorthite, hercynite, fayalite, gehlenite) at high temperature (HT) (1273–1403 K). These minerals can also interact to form eutectic mixtures in FeO‐SiO 2 ‐Al 2 O 3 and CaO‐SiO 2 ‐Al 2 O 3 systems and act as the most key factors for lowing melting mechanism of blended ash under gasification condition. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.