A key technology for synergistic backfilling of coal-based solid waste and high-salinity wastewater

Authors

DONG Shuning, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Coal Mine Hazard Prevention and Control National Key Laboratory, Xi’an 710077, China ; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, ChinaFollow
YU Shujiang, Beijing Symgreen Environmental Technology Group Co., Ltd., Beijing 100041, China
DONG Xingling, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Coal Mine Hazard Prevention and Control National Key Laboratory, Xi’an 710077, China ; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, ChinaFollow
ZHANG Buqin, Feny Co., Ltd., Changsha 410600, China
GUO Xiaoming, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Coal Mine Hazard Prevention and Control National Key Laboratory, Xi’an 710077, China ; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China
WANG Xiaodong, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Coal Mine Hazard Prevention and Control National Key Laboratory, Xi’an 710077, China ; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China
WANG Kai, Beijing Symgreen Environmental Technology Group Co., Ltd., Beijing 100041, China
ZHU Shibin, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Coal Mine Hazard Prevention and Control National Key Laboratory, Xi’an 710077, China ; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China
WU Boqiang, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Coal Mine Hazard Prevention and Control National Key Laboratory, Xi’an 710077, China ; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China
LIU Lei, CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Coal Mine Hazard Prevention and Control National Key Laboratory, Xi’an 710077, China ; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China

Abstract

Background and Objective 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. Methods 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). Results and Conclusions 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.

Keywords

coal-based solid waste, high-salinity water, solid-liquid synergism, downhole filling, groundwater

DOI

10.12363/issn.1001-1986.25.01.0032

Recommended Citation

DONG Shuning, YU Shujiang, DONG Xingling, et al. (2025) "A key technology for synergistic backfilling of coal-based solid waste and high-salinity wastewater," Coal Geology & Exploration: Vol. 53: Iss. 1, Article 13.
DOI: 10.12363/issn.1001-1986.25.01.0032
Available at: https://cge.researchcommons.org/journal/vol53/iss1/13

Reference

[1] 刘峰，郭林峰，赵路正. 双碳背景下煤炭安全区间与绿色低碳技术路径[J]. 煤炭学报，2022，47(1)：1−15.

LIU Feng，GUO Linfeng，ZHAO Luzheng. Research on coal safety range and green low–carbon technology path under the dual–carbon background[J]. Journal of China Coal Society，2022，47(1)：1−15.

[2] 董兴玲，董书宁，王皓，等. 古土壤层对煤矸石淋滤液中典型污染物的防污性能[J]. 煤炭学报，2021，46(6)：1957−1965.

DONG Xingling，DONG Shuning，WANG Hao，et al. Antifouling property of the paleosol layer to the contaminants in the coal gaugue leachate[J]. Journal of China Coal Society，2021，46(6)：1957−1965.

[3] 王玉涛. 煤矸石固废无害化处置与资源化综合利用现状与展望[J]. 煤田地质与勘探，2022，50(10)：54−66.

WANG Yutao. Status and prospect of harmless disposal and resource comprehensive utilization of solid waste of coal gangue[J]. Coal Geology & Exploration，2022，50(10)：54−66.

[4] 张吉雄，张强，周楠，等. 煤基固废充填开采技术研究进展与展望[J]. 煤炭学报，2022，47(12)：4167−4181.

ZHANG Jixiong，ZHANG Qiang，ZHOU Nan，et al. Research progress and prospect of coal based solid waste backfilling mining technology[J]. Journal of China Coal Society，2022，47(12)：4167−4181.

[5] LI Huajian，SUN Henghu，XIAO Xuejun，et al. Mechanical properties of gangue–containing aluminosilicate based cementitious materials[J]. Journal of University of Science and Technology Beijing，2006，13(2)：183−189.

[6] 杨科，赵新元，何祥，等. 多源煤基固废绿色充填基础理论与技术体系[J]. 煤炭学报，2022，47(12)：4201−4216.

YANG Ke，ZHAO Xinyuan，HE Xiang，et al. Basic theory and key technology of multi–source coal–based solid waste for green backfilling[J]. Journal of China Coal Society，2022，47(12)：4201−4216.

[7] 徐培杰，朱毅菲，曹永丹，等. 煤矸石资源高值化利用研究进展[J]. 环境工程学报，2023，17(10)：3137−3147.

XU Peijie，ZHU Yifei，CAO Yongdan，et al. Research progress of high–value utilization of coal gangue resources[J]. Chinese Journal of Environmental Engineering，2023，17(10)：3137−3147.

[8] 邱景平，李小庆，孙晓刚，等. 煤矸石资源化利用现状与进展[J]. 有色金属(矿山部分)，2014，66 (1)：47–50.

QIU Jingping，Ll Xiaoqing，SUN Xiaogang，et al. Status and progress in the utilization of coal gangue resources[J]. Nonferrous Metals (Mining Section)，2014，66 (1)：47–50.

[9] 张吉雄，屠世浩，曹亦俊，等. 煤矿井下煤矸智能分选与充填技术及工程应用[J]. 中国矿业大学学报，2021，50(3)：417–430.

ZHANG Jixiong，TU Shihao，CAO Yijun，et al. Coal gangue intelligent separation and backfilling technology and its engineering application in underground coal mine[J]. Journal of China University of Mining & Technology，2021，50(3)：417–430.

[10] 杨方亮，许红娜. “十四五”煤炭行业生态环境保护与资源综合利用发展路径分析[J]. 中国煤炭，2021，47(5)：73−82.

YANG Fangliang，XU Hongna. Analysis on the development path of ecological environment protection and resources comprehensive utilization in coal industry during the 14th Five–Year Plan period[J]. China Coal，2021，47(5)：73−82.

[11] 黄艳利，王文峰，卞正富. 新疆煤基固体废弃物处置与资源化利用研究[J]. 煤炭科学技术，2021，49(1)：319−330.

HUANG Yanli，WANG Wenfeng，BIAN Zhengfu. Prospects of resource utilization and disposal of coal–based solid wastes in Xinjiang[J]. Coal Science and Technology，2021，49(1)：319−330.

[12] 董猛，李江山，陈新，等. 煤系固废基绿色充填材料制备及其性能研究[J]. 煤田地质与勘探，2022，50(12)：75−84.

DONG Meng，LI Jiangshan，CHEN Xin，et al. Preparation of coal–series solid–waste–based green filling materials and their performance[J]. Coal Geology & Exploration，2022，50(12)：75−84.

[13] 董兴玲，董书宁，王宝，等. 黄土淋滤液作用下土工合成黏土衬垫的渗透特性研究[J]. 煤炭学报，2018，43(1)：228−235.

DONG Xingling，DONG Shuning，WANG Bao，et al. Hydraulic conductivity of geosynthetic clay liners to loess leachate[J]. Journal of China Coal Society，2018，43(1)：228−235.

[14] QURESHI A，CHRISTIAN M，ÖHLANDER B. Potential of coal mine waste rock for generating acid mine drainage[J]. Journal of Geochemical Exploration，2016，160：44−54.

[15] STEPHANIE N J，BORA C. Evaluation of waste materials for acid mine drainage remediation[J]. Fuel，2017，188：294−309.

[16] 郭强，宋喜东，虎晓龙，等. 高矿化度矿井水井下深度处理与浓盐水封存技术研究[J]. 煤炭工程，2020，52(12)：16−19.

GUO Qiang，SONG Xidong，HU Xiaolong，et al. Treatment of high salinity mine water and storage of concentrated brine[J]. Coal Engineering，2020，52(12)：16−19.

[17] SONG Qi，CHEN Xiaoguang，ZHOU Weizhu，et al. Application of a spiral symmetric stream anaerobic bioreactor for treating saline heparin sodium pharmaceutical wastewater：Reactor operating characteristics organics degradation pathway and salt tolerance mechanism[J]. Water Research，2021，205：117−123.

[18] 熊日华，何灿，马瑞，等. 高盐废水分盐结晶工艺及其技术经济分析[J]. 煤炭科学技术，2018，46(9)：37−43.

XIONG Rihua，HE Can，MA Rui，et al. Process introduction and techno–economic analysis on pure salt recovery crystallization for high salinity wastewater[J]. Coal Science and Technology，2018，46(9)：37−43.

[19] 李鑫，孙亚军，陈歌，等. 高矿化度矿井水深部转移存储介质条件及影响机制[J]. 煤田地质与勘探，2021，49(5)：17−28

LI Xin，SUN Yajun，CHEN Ge，et al. Medium conditons and influence mechanism of high salinity mine water transfer and storage by deep well recharge[J]. Coal Geology & Exploration，2021，49(5)：17−28.

[20] 谢丽清，王可，刘琼. 基于零排的高盐废水处理技术经济比选分析[J]. 水科学与工程技术，2024(2)：65−67.

XIE Liqing，WANG Ke，LIU Qiong. Technical and economic analysis of high–salinity wastewater treatment based on zero discharge[J]. Water Science and Engineering Technology，2024(2)：65−67.

[21] 王彦飞，杨静，王婧莹，等. 煤化工高浓盐废水蒸发处理工艺进展[J]. 无机盐工业，2017，49(1)：10−14.

WANG Yanfei，YANG Jing，WANG Jingying，et al. Progress in evaporation of high–salinity wastewater from coal chemical industry[J]. Inorganic Chemicals Industry，2017，49(1)：10−14.

[22] 姜兴涛，姜成旭. 利用蒸发塘处置煤化工浓盐水技术[J]. 化工进展，2012，31(增刊1)：276−278.

JIANG Xingtao，JIANG Chengxu. Technology of disposal of condensed coal chemical saltwater by evaporation–pool[J]. Chemical Industry and Engineering Progress，2012，31(Sup.1)：276−278.

[23] 古文哲，杨宝贵，朱磊，等. 矸石浆体充填空间特征研究与工程实践[J]. 矿业科学学报，2023，8(3)：409−418.

GU Wenzhe，YANG Baogui，ZHU Lei，et al. Study on spatial characteristics of gangue slurry filling mining and engineering practice[J]. Journal of Mining Science and Technology，2023，8(3)：409−418.

[24] 刘建功，王翰秋，赵家巍. 煤矿固体充填采煤技术发展回顾与展望[J]. 煤炭科学技术，2020，48(9)：27−38.

LIU Jiangong，WANG Hanqiu，ZHAO Jiawei. Review and prospect of development of solid backfill technology in coal mine[J]. Coal Science and Technology，2020，48(9)：27−38.

[25] 汪澜，颜碧兰，王昕，等. 不同重金属离子对C—S—H凝胶影响及其固化稳定性[J]. 建筑材料学报，2014，17(5)：790−796.

WANG Lan，YAN Bilan，WANG Xin，et al. Research on effect of different heavy metal lons on C–S–H gel and its stability[J]. Journal of Building Materials，2014，17(5)：790−796.

[26] 李肽脂，吴锋，李辉，等. 复合激发煤气化渣基胶凝材料的制备[J]. 环境工程学报，2022，16(7)：2356−2364.

LI Taizhi，WU Feng，LI Hui，et al. Preparation and microscopic mechanism of composite activated coal gasification slag–based cementitious materials[J]. Chinese Journal of Environmental Engineering，2022，16(7)：2356−2364.

[27] ZHAO Xinyuan，YANG Ke，HE Xiang，et al. Mix proportion and microscopic characterization of coal–based solid waste backfill material based on response surface methodology and multi–objective decision–making[J]. Scientific Reports，2024，14(1)：5672−5672.

[28] 谢和平，张吉雄，高峰，等. 煤矿负碳高效充填开采理论与技术构想[J]. 煤炭学报，2024，49(1)：36−46.

XIE Heping，ZHANG Jixiong，GAO Feng，et al. Theory and technical conception of carbon–negative and high–efficient backfill mining in coal mines[J]. Journal of China Coal Society，2024，49(1)：36−46.

[29] 孙希奎. “三下”采煤膏体充填开采技术研究[J]. 煤炭科学技术，2021，49(1)：218−224.

SUN Xikui. Research on paste backfilling mining technology of coal mining under buildings，water bodies and railways[J]. Coal Science and Technology，2021，49(1)：218−224.

[30] YANG Ke，ZHAO Xinyuan，WEI Zhen，et al. Development over–view of paste backfill technology in China’s coal mines：A review[J]. Environmental Science and Pollution Research，2021，28：67957−7969.

[31] 吴少康，张俊文，徐佑林，等. 煤矿高水充填材料物理力学特性研究及工程应用[J]. 采矿与安全工程学报，2023，40(4)：754–763.

WU Shaokang，ZHANG Junwen，XU Youlin，et al. Research and engineering application on physical and mechanical properties of coal mine high water filling materials[I]. Journal of Mining &Safety Engineering，2023，40(4)：754–763.

[32] 杨建，王强民，刘基，等. 煤矿井下不同区域矿井水中有机污染特征[J]. 煤炭学报，2018，43(增刊2)：546−552.

YANG Jian，WANG Qiangmin，LIU Ji，et al. Fluorescence characteristics of dissolved organic matter in underground different position of coal mine[J]. Journal of China Coal Society，2018，43(Sup.2)：546−552.

[33] 丁婷婷，李强，杜士林，等. 沙颍河流域水环境重金属污染特征及生态风险评价[J]. 环境化学，2019，38(10)：2386−2401.

DING Tingting，LI Qiang，DU Shilin，et al. Pollution characteristics and ecological risk assessment of heavy metals in Shaying River Basin[J]. Environmental Chemistry，2019，38(10)：2386−2401.

[34] 朱庚杰，朱万成，孙显腾，等. 高矿化度矿井水制备尾砂胶结充填体的强度性能[J]. 金属矿山，2023(3)：36−43.

ZHU Genjie，ZHU Wancheng，SUN Xianteng，et al. Strength properties of cemented tailings backfill mixed by high salinity underground mine water[J]. Metal Mine，2023(3)：36−43.