Xi Lei, Deng Taisen, Ma Qiang, Zhang Derun, Zhang Zeyu, Zhang Zhenglin
School of Civil Engineering, Architecture and Environment, Hubei University of Technology, No.28, Nanli Road, Hong-shan District, Wuhan, Hubei Province, 430068, China; Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes, Ministry of Education, Hubei University of Technology, China; Hubei Key Laboratory of Environmental Geotechnology and Ecological Remediation for Lake & River, Hubei University of Technology, China.
School of Civil Engineering, Architecture and Environment, Hubei University of Technology, No.28, Nanli Road, Hong-shan District, Wuhan, Hubei Province, 430068, China.
Environ Res. 2025 Sep 5;286(Pt 1):122696. doi: 10.1016/j.envres.2025.122696.
The production of phosphogypsum (PG), calcium carbide slag (CS), and red mud (RM) in global industrial development imposes serious environmental issues. Utilizing CS and PG as curing agents and incorporating RM as a soil substitute can facilitate the solid waste resource utilization. However, few studies have investigated the synergistic effects of PG and CS on the stabilization of RM and soil. To fulfill this research gap, this study explored the recycling of PG and CS for RM soil stabilization at varying RM ratio from 1:4 to 4:1. A series of tests on the stabilized RM soil composite were conducted, including the compaction test, unconfined compressive strength (UCS) test, consolidated-undrained triaxial compression test (CU), microscopic analyses (XRD and SEM), and toxicity characteristic leaching procedure (TCLP) test. The test results indicated that the maximum dry density (MDD) of the RM soil composite increased as the RM ratio increased from 1:4 to 4:1. When the PG content exceeds 8 %, the RM soil composite becomes loose, leading to a decrease in UC and ultimate deviatoricic stress. The synergistic effect of PG-CS can reduce the leaching of Cr, Cd, and Pb significantly by 54.6 %, 32.7 %, and 21.9 % respectively. When appropriate amounts of PG and CS are incorporated, considerable cementitious hydration products such as C-S-H/C-A-S-H and Aft will be generated. These hydration products can adhere to the surface of RM and soil particles or fill the gaps between particles, making the soil structure dense and stable, thereby significantly improving its mechanical performance. The optimal dosages of PG and CS were identified as 8 % and 12 %, respectively. The combined use of PG and CS is found to significantly enhance the strength of the RM-soil composite and inhibit the leaching of heavy metals, which promotes the large-scale utilization of solid waste of PG and CS.
在全球工业发展过程中，磷石膏（PG）、电石渣（CS）和赤泥（RM）的产生带来了严重的环境问题。利用CS和PG作为固化剂，并掺入RM作为土壤替代物，能够促进固体废物的资源利用。然而，很少有研究探讨PG和CS对RM与土壤稳定化的协同效应。为填补这一研究空白，本研究探索了在RM比例从1:4到4:1变化时，利用PG和CS对RM土壤进行稳定化处理。对稳定后的RM土壤复合材料进行了一系列试验，包括压实试验、无侧限抗压强度（UCS）试验、固结不排水三轴压缩试验（CU）、微观分析（XRD和SEM）以及毒性特征浸出程序（TCLP）试验。试验结果表明，RM土壤复合材料的最大干密度（MDD）随着RM比例从1:4增加到4:1而增大。当PG含量超过8%时，RM土壤复合材料会变得松散，导致无侧限抗压强度和极限偏应力降低。PG-CS的协同效应可显著降低Cr、Cd和Pb的浸出量，分别降低54.6%、32.7%和21.9%。当掺入适量的PG和CS时，会生成大量的胶凝水化产物，如C-S-H/C-A-S-H和钙矾石。这些水化产物能够附着在RM和土壤颗粒表面或填充颗粒间的空隙，使土壤结构致密且稳定，从而显著提高其力学性能。确定PG和CS的最佳剂量分别为8%和12%。发现PG和CS的联合使用能显著提高RM-土壤复合材料的强度并抑制重金属的浸出，这促进了PG和CS固体废物的大规模利用。
