Leaching behavior of arsenic and selenium in coal fly ash by aging treatment and cement mixing
Leaching behavior of arsenic and selenium in coal fly ash by aging treatment and cement mixing
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DOI：
10.1080/00223131.2023.2176378
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发表时间：
2023-03
影响因子：
1.2
通讯作者：
Tsugumi Seki;Y. Ogawa;Koki Ibi;Taiji Chida;C. Inoue;Y. Niibori
中科院分区：
文献类型：
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作者：
Tsugumi Seki;Y. Ogawa;Koki Ibi;Taiji Chida;C. Inoue;Y. Niibori
摘要 在粉煤灰（FA）混合水泥的使用中，评估 FA 中有毒元素的浸出率至关重要。本研究评估了 40 种原始 FA (R-FA)、老化处理 FA (A-FA) 和水泥混合 FA (C-FA) 中砷和硒的浸出行为。 R-FA 中砷的平均浸出浓度为 0.03 mg/L，硒的平均浸出浓度为 0.09 mg/L。时效处理抑制了砷和硒的浸出，其中砷和硒掺量低于0.01 mg/L的水泥掺入更显着地抑制了砷和硒的浸出。 R-FA 的 pH 范围为 7.6 至 12.9，C-FA 的 pH 范围为 11.1 至 12.3，由于水泥混合，pH 范围较小。此外，R-FAs和C-FAs随时间的浸出实验结果表明，由于水泥中钙的供应，砷和硒的浸出因与钙形成次级化合物而受到抑制。这些结果表明，实际现场使用的普通FA水泥和低碱性水泥能够充分抑制砷和硒的浸出，因为水泥用量与FA的比例高于本研究的比例。图解摘要
ABSTRACT In the use of coal fly ash (FA) mixed cement, the assessment of the leachabilities of toxic elements in FA is crucial. This study evaluated the leaching behavior of arsenic and selenium in 40 types of raw FA (R-FA), aging-treated FA (A-FA), and cement-mixed FA (C-FA). The mean leaching concentrations from R-FAs were 0.03 mg/L for arsenic and 0.09 mg/L for selenium. The leaching of arsenic and selenium was suppressed by the aging treatment, and more significantly suppressed by the cement mixing under 0.01 mg/L for both arsenic and selenium. The pH for R-FAs ranged from 7.6 to 12.9, and that for C-FAs ranged from 11.1 to 12.3 with a smaller pH range due to cement mixing. Furthermore, the results of the leaching experiment with time for R-FAs and C-FAs indicated that the leaching of arsenic and selenium was suppressed by the formation of secondary compounds with calcium due to the supply of calcium from the cement. These results indicate that the common FA cement and low alkaline cement used in the actual site can sufficiently suppress the leaching of arsenic and selenium because the ratio of cement amount to FA is higher than that examined in this study. GRAPHICAL ABSTRACT