State Key Laboratory of Coal Resources and Safe Mining, University of Mining & Technology, XuzhouChin, 221116, Jiangsu, China.
School of Mines, China University of Mining & Technology, Xuzhou, 221116, Jiangsu, China.
Environ Sci Pollut Res Int. 2022 Jun;29(30):45774-45782. doi: 10.1007/s11356-022-18975-9. Epub 2022 Feb 12.
The treatment of coal gangue solid waste and microbially induced calcium carbonate precipitation (MICP) consolidate technology is a focus of research at home and abroad. MICP technology was used to solidify and cement coal gangue particles and endows them with a certain strength. The process does not use the traditional cementitious material (Portland cement) and is eco-friendly and pollution-free. The mechanical properties including unconfined compressive strength, CaCO content, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and infrared spectroscopy (FTIR) were used for macroscopic and microscopic analyses. The results show that the average strength of CG-based bio-mineralized backfill materials reaches 1.55 MPa and the maximum strength is 2.17 MPa, suggesting the potential for its use as an underground fill. Compared with unmineralized gangue, the CaCO crystal content in CG-based mineralized material is increased by 8.75% on average, and the maximum content is 13.34%. In the process of bacterial liquid perfusion, there is uneven distribution of bacteria in the material, which results in fewer CaCO crystals being locally generated in the mineralized material and affects the overall compressive strength of gangue columns. Moreover, the greater the amount of calcium carbonate, the larger the strength of the mineralized material. SEM analysis results indicate that the gaps between gangue particles are filled with CaCO crystals, and the calcium carbonate crystals are mostly polyhedral, showing stacked growth and contain a small number of spherical crystals that exist alone. The results of FTIR and EDS analysis show that the CaCO crystals in the mineralized material are mainly in the form of calcite, followed by a small amount of vaterite. Comprehensive analysis demonstrates that the preparation of CG-based bio-mineralized backfilling materials is successful, and this experiment provides new ideas and methods for the treatment of solid waste such as coal gangue and building material waste.
煤矸石固废处理与微生物诱导碳酸钙沉淀（MICP）固结技术是国内外研究的热点。MICP 技术用于固化和胶结煤矸石颗粒，赋予其一定的强度。该工艺不使用传统的胶凝材料（硅酸盐水泥），具有环保和无污染的特点。通过无侧限抗压强度、碳酸钙含量、扫描电子显微镜（SEM）、能谱分析（EDS）和傅里叶变换红外光谱（FTIR）等方法进行宏观和微观分析。结果表明，基于 CG 的生物矿化充填材料的平均强度达到 1.55 MPa，最大强度达到 2.17 MPa，表明其具有作为地下充填材料的潜力。与未矿化矸石相比，CG 基矿化材料中的碳酸钙晶体含量平均增加了 8.75%，最大含量为 13.34%。在细菌液灌注过程中，材料中细菌分布不均匀，导致矿化材料中局部生成的碳酸钙晶体较少，影响矸石柱的整体抗压强度。此外，碳酸钙含量越大，矿化材料的强度越大。SEM 分析结果表明，矸石颗粒之间的间隙被碳酸钙晶体填充，碳酸钙晶体多为多面体，呈堆叠生长，含有少量单独存在的球形晶体。FTIR 和 EDS 分析结果表明，矿化材料中的碳酸钙晶体主要以方解石的形式存在，其次是少量的文石。综合分析表明，CG 基生物矿化充填材料的制备是成功的，该实验为煤矸石等固体废弃物和建筑废料的处理提供了新的思路和方法。
