赤泥基固化剂固化/稳定铅锌镉污染土的强度及浸出特性研究  

Study on the strength and leaching characteristics of solidified/stabilized lead,zinc and cadmium contaminated soil with red mud-based curing agent

作　　者：郭明帅 潘浩[1] 王菲[1] GUO Mingshuai;PAN Hao;WANG Fei(Institute of Geotechnical Engineering,Southeast University,Nanjing,Jiangsu 210096,China)

机构地区：[1]东南大学岩土工程研究所,江苏南京210096

出　　处：《岩石力学与工程学报》2021年第S01期2968-2975,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上基金资助项目(51978157);国家自然科学基金青年基金资助项目(51608113)。

摘　　要：采用赤泥-磷石膏-水泥(RPPC)、赤泥-磷石膏-生石灰(RPCA)两种赤泥基固化剂以及普通水泥(PC)对人工制备的铅、锌、镉污染土进行固化/稳定化,进一步优化赤泥基固化剂的配比。对养护7和28 d后的试样开展无侧限抗压强度、毒性浸出试验和pH梯度试验。研究发现,随着固化剂掺量和养护龄期的增加,赤泥基固化剂固化样的无侧限抗压强度逐渐增加,且强度间差值逐渐增加。三种固化剂的固化样浸出液pH值均分布在7~9范围内。28 d养护龄期后,15%掺量的赤泥基固化剂均有较好的强度和固化效果。相较而言,RPPC固化剂比RPCA固化剂具有更好的固化/稳定化效果,其无侧限抗压强度较高,重金属浸出浓度较低。pH梯度试验结果表明,pH=8时RPPC固化样的重金属浸出浓度最低。不同的浸提剂pH值下,浸出浓度仍满足随掺量增加而增加的趋势。Red mud-phosphogypsum-cement(RPPC),red mud-phosphogypsum-quick lime(RPCA)and ordinary cement(PC)were used to solidify/stabilize the artificially prepared lead,zinc,and cadmium contaminated soil.Then the ratio of red mud-based curing agent was optimized.After the samples were cured for 7 days and 28 days respectively,unconfined compressive strength,toxic leaching test and pH gradient test were carried out.The research results show that with the increase of curing agent content and curing age,the unconfined compressive strength of the samples cured with red mud-based curing agents gradually increases.The difference between the strengths gradually increases.The pH of the leaching solution of the samples cured by the three curing agents are in the range of 7-9.After 28 d curing age,the red mud-based curing agents with 15%content have good strength and curing effect.In comparison,RPPC has better solidifying/stabilizing effect than RPCA.And RPPC has higher unconfined compressive strength and lower heavy metal leaching concentration.The pH gradient test results show that the leaching concentration of heavy metals in RPPC solidified samples was the lowest when pH=8.Under different pH values of the extractant,the leaching concentration still meets the trend of increasing with the increase of the content.

关 键 词：土力学 赤泥 固化/稳定化 重金属 抗压强度 浸出 

分 类 号：TU43[建筑科学—岩土工程]