Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai, Miyagi Pref., 980-8579, Japan.
Department of Earth Resource Engineering and Environmental Science, Faculty of International Resource Sciences, Akita University, Tegatagakuen-machi 1-1, Akita, Akita Pref., 010-8502, Japan.
Environ Monit Assess. 2021 Mar 26;193(4):225. doi: 10.1007/s10661-021-08954-x.
Coal fly ash (CFA) is a useful recycled resource for uses such as cement raw material. To manage and evaluate safety for effective utilization of CFA, the leaching concentration and amounts of toxic elements in CFA need to be determined. In this study, 38 types of CFA and aged CFA generated in Japan were used to measure the occurrence and leaching concentration range of As and Se. In addition, the leaching characteristics over the long term were examined using statistical analysis. Leaching concentrations of As and Se from CFAs were in the range of 0.001-0.163 mg/L (average: 0.025 mg/L, median: 0.014 mg/L) and 0.001-0.189 mg/L (average: 0.071 mg/L, median: 0.055 mg/L), respectively. In general, the concentrations of aged CFAs were less than those of the CFAs with a few exceptions. Leaching concentrations of As and Se in the tank leaching test changed with time, and As and Se concentrations in the dispersions increased with stirring time. In contrast, pH of the dispersion decreased with time. The relation between As or Se and CFA factors showed that As or Se and pH or Ca were highly correlated. However, in aged CFAs for long-term use, the correlation coefficient for the relation between As and other factors was low while that for Se-S was high. Considering the effective utilization of CFA as a long-term recyclable resource, the leaching processes of As and Se in CFA would change with time depending on the environmental conditions.
粉煤灰（CFA）是一种有用的再生资源，可用于水泥原料等用途。为了管理和评估 CFA 的有效利用安全性，需要确定 CFA 中有毒元素的浸出浓度和含量。在这项研究中，使用了日本产生的 38 种 CFA 和陈化 CFA，以测量 As 和 Se 的存在和浸出浓度范围。此外，还通过统计分析检查了长期的浸出特性。CFA 中 As 和 Se 的浸出浓度在 0.001-0.163 mg/L（平均值：0.025 mg/L，中位数：0.014 mg/L）和 0.001-0.189 mg/L（平均值：0.071 mg/L，中位数：0.055 mg/L）之间。一般来说，陈化 CFA 的浓度小于 CFA 的浓度，但也有例外。罐浸出试验中 As 和 Se 的浸出浓度随时间变化，分散体中的 As 和 Se 浓度随搅拌时间增加而增加。相比之下，分散体的 pH 值随时间降低。As 或 Se 与 CFA 因素之间的关系表明，As 或 Se 与 pH 值或 Ca 高度相关。然而，在长期使用的陈化 CFA 中，As 与其他因素之间关系的相关系数较低，而 Se-S 之间的相关系数较高。考虑到 CFA 作为长期可回收资源的有效利用，CFA 中 As 和 Se 的浸出过程会随时间而变化，这取决于环境条件。
