Ogawa Yasumasa, Sakakibara Kento, Wang Li, Suto Koichi, Inoue Chihiro
Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan,
Environ Monit Assess. 2014 Oct;186(10):6757-70. doi: 10.1007/s10661-014-3887-2. Epub 2014 Jul 10.
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.
实验使用了14种不同的碱性煤粉煤灰（CFA），每个样品与水混合，使含水量达到28.6%（重量/重量），并在10 - 30°C下老化1 - 4周。这种简单处理有利于降低水溶性硼、氟、铬和砷的含量。与未老化的CFA相比，在20°C下老化一周后，它们的水溶性部分分别保持在0.56 - 88%、21 - 85%、0.37 - 93%和2.6 - 88%，尽管一些CFA样品中释放的铬和砷的量有所增加。考虑到老化后硫酸盐、钙和铝的洗脱量显著下降，这种固定作用，即防止有毒元素洗脱，可能与次生矿物如氢氧化钙、石膏和钙矾石的形成有关。硼和铬的固定作用在较冷的条件下往往优先进行。在较高温度下老化会增加一些CFA样品中铬的浸出性。与硼和铬的行为相反，在温暖条件下，水溶性氟有效地减少。
