王永好,林裕智,李明洋,时坚,王永净,张静.硫化砷渣一步水热成矿转化固砷与硫回收[J].环境科学学报,2021,41(8):3324-3332
硫化砷渣一步水热成矿转化固砷与硫回收
- Hydrothermal treatment of arsenic sulfide slag to immobilize arsenic into arsenical natroalunite and recycle sulfur
- 基金项目：国家自然科学基金重点项目（No.21836002）
- 王永好
- 福州大学环境与安全工程学院, 福州 350108
- 林裕智
- 福州大学环境与安全工程学院, 福州 350108
- 李明洋
- 福州大学环境与安全工程学院, 福州 350108
- 时坚
- 福州大学环境与安全工程学院, 福州 350108
- 王永净
- 福州大学环境与安全工程学院, 福州 350108
- 张静
- 中国科学院生态环境研究中心, 北京 100085
- 摘要：含砷工业废水的处理通常会产生大量的含砷废渣，砷渣中的砷元素在各种环境因素的影响下容易重新释放到环境中.因此，本研究以模拟硫化砷渣作为典型含砷废渣，通过在水热条件下添加Al3+、SO42-和Na+，将硫化砷渣一步直接转化成稳定的砷钠明矾石，同时回收单质硫.结果表明，最优的转化条件为：Al/As物质的量比为3：1，pH为2，水热温度和时间分别为200 ℃和2 h；EDS测试和红外谱图表明，部分砷酸根代替了钠明矾石中的硫酸根离子，从而生成了砷钠明矾石；砷钠明矾石的短期毒性浸出实验表明其在pH值为2~11的浸出液中砷的浸出浓度均小于0.05 mg·L-1，参照《HJ/T 300-2007固体废物浸出毒性浸出方法醋酸缓冲溶液法》的标准，利用pH=4.93的醋酸缓冲溶液浸渍砷钠明矾石90 d后，砷的浸出浓度依然小于0.05 mg·L-1，由此说明转化后的砷钠明矾石具有优越的稳定性.最后利用该方法处理河南和福建两地的某砷渣，结果表明，两种实际砷渣中的砷浸出浓度均由原来的大于400 mg·L-1降低到处理后的小于0.1 mg·L-1，远低于国家危险废物鉴别标准中的限值（5 mg·L-1）；另外，该方法在稳定硫化砷渣的同时还可以回收单质硫，为砷渣的处理与资源化利用提供了一种新思路.
- Abstract：Arsenic waste residues (ArWR), originating from the treatment of As-containing wastewater, generally exist in amorphous state. Arsenic element might be released into the environment from the ArWR because of the complex natural conditions. In this work, the stabilization method of arsenic sulfide residues was investigated in the existence of Al3+, SO42- and Na+. It was found that arsenic sulfides transformed into arsenical natroalunite and elemental sulfur under hydrothermal conditions. The optimum conversion parameters were shown as following. The ratio of Al to As was 3：1, pH value was ~2, the reaction temperature was 200 ℃ and the reaction time was 2 h. The results of EDS observation and the infrared spectra (IR) indicated that SO42- in natroalunite was partly substituted as AsO43-, forming arsenical natroalunite. The concentration of arsenic element for arsenical natroalunite was less than 0.05 mg·L-1 with leaching pH value from 2 to 11. Moreover, the concentration of arsenic element for arsenical natroalunite was still less than 0.05 mg·L-1 after 90-days leaching experiment in acetic acid buffer solution. Based on the above results, arsenical natroalunite has superior stability. Finally, two kinds of real ArWRs (originated from Henan and Fujian Province) were studied by above method in order to evaluate the universality of this method. It was found that the concentrate of arsenic element decreased from >400 mg·L-1 to <0.1 mg·L-1, which indicated that this protocol is a promising method for the treatment and recycling of ArWR.
