受地域、经济和技术水平等限制，大部分煤基固废仍以露天堆填的形式积存而未进行处置，不仅占用大量土地资源，还会对环境造成二次污染。高盐废水(如矿井高盐水、煤化工高盐水)的妥善处置及减量化是实现废水“零排放”的关键环节，然而现有高盐废水处理技术普遍存在工程初期投资大、运行费用较高等问题。

提出煤基固废和高盐废水“固液”两废协同处理技术，即使用高盐废水代替普通用水和早强剂等添加剂，采用固废胶凝材料代替水泥材料，将煤基固废和高盐废水搅拌混合后得到充填膏体，泵送至煤矿井下空间。为了分析该技术的可行性，以宁夏宁东煤炭基地某煤矿为研究区，研究煤基固废充填膏体的力学性能及其对环境的潜在影响。采用单轴抗压强度测试试验(UCS)、扫描电镜(SEM)和电感耦合等离子体质谱仪(ICP-MS)分析固化充填膏体的力学性能、微观结构及重金属浸出特征。

结果表明：随着时间的延长，固化充填膏体的强度不断增加，而随着矿粉添加量的增多，胶凝材料比例下降，固化充填膏体的强度逐渐减小。值得注意的是，随着时间延长，所有使用高盐废水作为拌合水的充填膏体3 d强度都高于0.5 MPa，基本满足NB/T 11432—2023《煤矿矸石基固废充填技术规范》中的最低要求，14 d强度达到3.38~5.99 MPa，能够满足绝大部分煤矿充填的各种场景要求。内梅罗污染指数法评价结果显示，固化充填膏体浸出液中重金属的综合污染指数为0.25，评价分级标准为安全；从固化充填膏体的浸出试验结果可以看出，浸出液中主要污染物的浓度均低于GB 5085.3—2007《危险废物鉴别标准 浸出毒性鉴别》及GB/T 14848—2017《地下水质量标准》中所列的Ⅲ类水标准要求。因此，煤基固废和矿井高盐水协同处理技术，在力学性能和环境稳定性评估方面均满足相关标准，可实现煤基固废及高盐废水的可循环、低成本和全量化利用，具有显著的经济效益和环境生态效益，在无废矿山、无废化工建设方面有较好的应用前景。

Limited by locations, as well as economic and technical levels, most of the coal-based solid waste is still accumulated in the form of open-air landfills without treatment, thus occupying large quantities of land resources and causing secondary pollution to the environment. The proper treatment and reduction of high-salinity wastewater (e.g., high-salinity mine water and high-salinity water from the coal chemical industry) represent a key link in the achievement of zero liquid discharge. However, existing technologies for high-salinity wastewater treatment are generally confronted with issues such as great initial investment and high operation costs of the treatment engineering.

This study developed a technology for the synergistic treatment of coal-based solid waste and high-salinity wastewater (also referred to as solid-liquid synergistic waste backfilling). Specifically, high-salinity water, rather than ordinary water and additives such as early strength agent, and solid waste cementitious materials—used to replacing part of cement, were mixed while stirring to produce filling paste, which was then pumped to the underground goaves of coal mines. To analyze the feasibility of this technology, this study investigated the mechanical properties and potential environmental impacts of filling paste prepared using coal-based solid waste and high-salinity wastewater from a certain coal mine in the Ningdong coal base in Ningxia. The mechanical properties, microstructures, and heavy metal leaching characteristics of the solidified filling paste were analyzed using the uniaxial compressive strength (UCS) test, scanning electron microscopy (SEM), and inductively coupled plasma-mass spectrometry (ICP-MS).

The results indicate that the strength of all the solidified filling paste increased over time but gradually decreased with an increase in the quantity of mineral powders added and a decrease in the proportion of cementitious materials. Notably, after some time, all filling paste prepared using high-salinity water as mixing water exhibited 3-day strength exceeding 0.5 MPa, meeting the minimum requirements specified in Technical specification for coal mine gangue-based solid waste filling (NB/T 11432—2023). Their 14-day strength reached 3.38‒5.99 MPa, satisfying the requirements of various scenarios in most coal mine filling. The assessment results obtained using Nemerow’s pollution index and extraction toxicity tests indicate that the leachate from the solidified filling paste exhibited a comprehensive pollution index of heavy metals of 0.25, rated as “Safety” according to the grading criteria for comprehensive pollution assessment. The leaching test results of the solidified filling paste indicate that the primary pollutant concentrations in the leachate all fell below the requirements of Class III water standard specified in Identification standards for hazardous wastes-Identification for extraction toxicity (GB 5085.3—2007) and Standard for groundwater quality (GB/T 14848—2017). Therefore, the technology for synergistic treatment of coal-based solid waste and mine high-salinity water can meet the relevant standards in the assessment of mechanical properties and environmental stability. This technology enables the recyclable, low-cost, and full quantitative utilization of coal-based solid waste and high-salinity water, enjoying significant economic and ecological benefits. The results of this study will provide technological support for the construction of waste-free mines, mining cities, and chemical industry.