摘要
针对酸化含硫铅锌尾矿砂因含有大量可浸出SO_(4)^(2-)和重金属离子而不宜用作建筑骨料的问题,以湖南省某铅锌矿的尾矿砂为原料,首先采用硫酸盐还原菌(sulfate-reducing bacteria,SRB)对尾矿砂进行预处理,通过污染物浸出试验分析其污染物控制效果;然后将处理前后的尾矿砂以不同质量等比例替代天然河砂制备水泥砂浆试块,开展单轴抗压强度试验测试其强度;最后开展电镜扫描试验,揭示不同替代率下尾矿砂水泥砂浆微观形貌特征。研究结果表明:SRB对SO_(4)^(2-)和Cu^(2+)、Mn^(2+)、Zn^(2+)、Cr^(6+)等重金属离子去除效果良好;经SRB处理后的尾矿砂水泥砂浆在不同替代情况下的抗压强度均高于未处理的尾矿砂水泥砂浆,尾矿砂掺量在质量分数为10%时强度最高;适量铅锌尾砂的掺入,优化了孔隙结构,使砂浆抗压强度提高;原状铅锌尾矿砂中含有大量SO_(4)^(2-),易生成钙矾石等膨胀性水化产物使砂浆内部产生较多裂缝,这是其强度劣化的主要机理。
Acidified sulfur-containing lead-zinc tailings are not suitable for use as building aggregates because they contain a large amount of leachable SO_(4)^(2-)and heavy metal ions.The tailings of a lead-zinc mine in Hunan Province were used as raw materials.Firstly,sulfate-reducing bacteria(SRB)were used to pretreat the tailings,and the pollutant control effect was analyzed by pollutant leaching test.Then,the tailings sand before and after treatment was used to replace the natural river sand with different mass ratios to prepare cement mortar test blocks,and the uniaxial compressive strength test was carried out to test its strength.Finally,the electron microscope scanning test was carried out to reveal the microscopic morphology characteristics of tailings sand cement mortar under different rate of substitution.The research results show that SRB has a good removal effect on SO_(4)^(2-)and heavy metal ions such as Cu^(2+),Mn^(2+),Zn^(2+)and Cr^(6+).The compressive strength of tailings sand cement mortar treated by SRB under different substitution conditions is higher than that of untreated tailings sand cement mortar,and the strength is the highest when the tailings sand content is 10%.The incorporation of appropriate amount of lead-zinc tailings optimizes the pore structure and improves the compressive strength of mortar.The original lead-zinc tailings sand contains a large amount of SO_(4)^(2-),which is easy to produce expansive hydration products such as ettringite,and causes more cracks in the mortar,and that is the main mechanism of its strength degradation.
作者
陈文昭
卢铎方
杨鑫宏
刘夕奇
刘俊
CHEN Wenzhao;LU Duofang;YANG Xinhong;LIU Xiqi;LIU Jun(School of Civil Engineering,University of South China,Hengyang,Hunan 421001,China;Pearl River Water Resources Research Institute,Guangzhou,Guangdong 510611,China)
出处
《南华大学学报(自然科学版)》
2024年第6期27-35,共9页
Journal of University of South China:Science and Technology
基金
湖南省自然科学基金项目(2023JJ30511)
湖南省自然资源科研项目(20230144DZ)
湖南省教育厅项目(重点)(18A252)
湖南省研究生科研创新项目(QL20220216)。
关键词
SRB
铅锌尾矿砂
破坏形态
抗压强度
微观结构
sulfate-reducing bacteria
lead-zinc tailings
destruction form
compressive strength
microstructure
作者简介
陈文昭(1969-),男,副教授,博士,主要从事岩土力学、岩土工程灾害防治、地质灾害防治、尾矿坝安全等方面的研究。E-mail:chengwz@usc.edu.cn。
