TY - JOUR
T1 - Immobilization of B, F, Cr, and As in alkaline coal fly ash through an aging process with water
AU - Ogawa, Yasumasa
AU - Sakakibara, Kento
AU - Wang, Li
AU - Suto, Koichi
AU - Inoue, Chihiro
N1 - Publisher Copyright:
© 2014, Springer International Publishing Switzerland.
PY - 2014/10/1
Y1 - 2014/10/1
N2 - Fourteen different alkaline coal fly ashes (CFAs) were used for the experiment, in which each sample was mixed with water to be 28.6 % of water content (wt/wt) and aged for 1–4 weeks at 10–30 °C. This simple treatment is advantageous for decreases in water-soluble B, F, Cr, and As. Compared to non-aged CFAs, their water-soluble fractions remained 0.56–88 %, 21–85 %, 0.37–93 % and 2.6–88 %, respectively, after aging for a week at 20 °C, although the amounts of Cr and As released from some CFA samples increased. Considering the significant decrease in elution of sulfate, Ca and Al after aging, the immobilization, namely prevention of toxic element elution, could be related to formation of secondary minerals such as portlandite, gypsum and ettringite. Immobilization of B and Cr tends to proceed preferentially under colder conditions. Aging at higher temperatures enhances the leachability of Cr in some CFA samples. Contrary to the behavior of B and Cr, water-soluble F effectively decreases under warmer conditions.
AB - Fourteen different alkaline coal fly ashes (CFAs) were used for the experiment, in which each sample was mixed with water to be 28.6 % of water content (wt/wt) and aged for 1–4 weeks at 10–30 °C. This simple treatment is advantageous for decreases in water-soluble B, F, Cr, and As. Compared to non-aged CFAs, their water-soluble fractions remained 0.56–88 %, 21–85 %, 0.37–93 % and 2.6–88 %, respectively, after aging for a week at 20 °C, although the amounts of Cr and As released from some CFA samples increased. Considering the significant decrease in elution of sulfate, Ca and Al after aging, the immobilization, namely prevention of toxic element elution, could be related to formation of secondary minerals such as portlandite, gypsum and ettringite. Immobilization of B and Cr tends to proceed preferentially under colder conditions. Aging at higher temperatures enhances the leachability of Cr in some CFA samples. Contrary to the behavior of B and Cr, water-soluble F effectively decreases under warmer conditions.
KW - Coal fly ash
KW - Immobilization
KW - Leaching
KW - Toxic elements
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U2 - 10.1007/s10661-014-3887-2
DO - 10.1007/s10661-014-3887-2
M3 - Article
C2 - 25004853
AN - SCOPUS:84921693341
SN - 0167-6369
VL - 186
SP - 6757
EP - 6770
JO - Environmental Monitoring and Assessment
JF - Environmental Monitoring and Assessment
IS - 10
ER -