Evaluating temperature effects on leaching behavior of geogenic arsenic and boron from crushed excavated rocks using shaking and nonshaking batch tests
Evaluating temperature effects on leaching behavior of geogenic arsenic and boron from crushed excavated rocks using shaking and nonshaking batch tests
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DOI：
10.1016/j.sandf.2023.101274
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发表时间：
2023-01-23
影响因子：
3.7
通讯作者：
Katsumi, Takeshi
中科院分区：
文献类型：
--
作者：
Kato, Tomohiro;Takai, Atsushi;Katsumi, Takeshi
通过两种不同温度下含地质污染物的开挖岩石，评价了砷和硼的浸出行为。含地质污染物的开挖岩石有望用于采矿，并针对地质污染带来的风险采取适当的对策。土壤的淋溶行为可能会因地温的变化而发生变化。然而，温度对这种岩石的浸出行为的影响还没有得到很好的研究。在此，在摇动和非摇动条件下在5至60 ° C的温度下进行分批浸出试验。泥岩和页岩被粉碎成小于2 mm的颗粒，这是测试所需的。试验持续时间从6小时到15天不等，因为浸出动力学的变化也需要仔细评估。在40摄氏度下进行15天的非振动测试后，泥岩样本浸出的砷和硼浓度分别约为0.7和1.0 mg/L。砷和硼的浓度比在20 ℃下浸提的样品高约20%和40%。温度升高会增加有毒元素的浸出动力学。对于页岩样品，砷的浸出率在40 ℃时为7.7 × 10-2/h，比30 ℃时的值高约2.5倍。非振荡试验表明砷和硼的浸出量高于振荡试验，特别是在高温下。由于应避免不切实际的估计，建议进行非振动试验。此外，由于矿物质溶解相对较慢，需要进行持续时间超过6小时的非摇动试验。(c)2023年由Elsevier B. V.代表日本岩土学会制作和主办。这是CC BY -NC-ND许可下的开放获取文章（http：//creativecommons.org/licenses/by-nc-nd/4.0/）。
The leaching behavior of arsenic and boron is evaluated in this work through two types of excavated rocks with geogenic contaminants under different temperatures. Excavated rocks with geogenic contaminants are expected to be used in embankments with appropriate coun-termeasures being taken against the risks brought about by geogenic contamination. The leaching behavior might change because of changes in the ground temperature. However, the effects of temperature on the leaching behavior of such rocks have not been well examined. Herein, batch leaching tests at temperatures between 5 and 60 degrees C were performed under shaking and nonshaking conditions. Mudstone and shale rock were crushed into particles smaller than 2 mm, which were required for the tests. The tests were carried out for durations ranging from 6 h to 15 days because changes in leaching kinetics also require careful evaluation. After conducting the nonshaking tests for 15 days at 40 degrees C, the mudstone sample leached arsenic and boron at concentrations of approximately 0.7 and 1.0 mg/L, respectively. The arsenic and boron concentrations were about 20 and 40% higher than those of the sample leached at a temperature of 20 degrees C. Elevated temperatures were seen to increase the leaching kinetics of the toxic elements. For the shale rock sample, the leaching rate for arsenic was 7.7 x 10-2/h at 40 degrees C, which was about 2.5 times greater than the value at 30 degrees C. The nonshaking tests showed higher leaching amounts of arsenic and boron than the shaking tests, especially at elevated temperatures. As unrealistic estimations should be avoided, nonshaking tests are suggested. More-over, nonshaking tests lasting longer than 6 h are necessary due to the relatively slow dissolution of minerals. (c) 2023 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BY -NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).