摘要
神华神东矿区许多矿井水中氟化物(F^(-))质量浓度超标(>1 mg/L),给矿井水的利用和排放带来巨大挑战。为了调查矿井水中氟化物的潜在来源以及研究高氟矿井水的形成机制,从神东矿区8个煤矿采集了矿井水、萨拉乌苏组松散层潜水以及地表水样品共81个,进行了氢氧同位素和主要离子质量浓度测定。测试结果显示:神东矿区矿井水中F^(-)质量浓度介于0.05~11.65 mg/L,平均为1.96 mg/L,其中51%的矿井水为高氟矿井水。氢氧同位素分析表明绝大多数的高氟矿井水具有偏轻的δD和δ^(18)O,且随着F^(-)质量浓度的增高,δD和δ^(18)O降低。分析认为,δD和δ^(18)O偏轻的矿井水相对古老,滞留时间长,其与松散层潜水以及地表水的水力联系较差,处于相对封闭的地下水环境,径流滞缓,水-岩反应充分,当含水层的矿物学和地球化学条件适宜条件下,含氟矿物中氟释放,导致水中F^(-)的富集。矿井水水化学类型与F^(-)质量浓度的关联性分析显示,Na-HCO_(3)型水具有最高的F^(-)质量浓度;所有的高氟矿井水均为Na型水,Na型矿井水中F^(-)的质量浓度明显高于Ca型矿井水,随着Na^(+)质量浓度的增高和Ca^(2+)质量浓度的降低,F^(-)质量浓度升高,反映出F^(-)的富集主要与矿井水中Na^(+)增高以及Ca^(2+)消耗的水-岩作用有关。综合分析认为,神东矿区高氟矿井水的形成主要与矿井水中Ca^(2+)与岩石表面吸附的Na^(+)的阳离子交换吸附作用有关,同时,较高的碱性水环境下OH^(-)-F^(-)阴离子交换以及Ca(OH)_(2)矿物沉淀也有助于矿井水中F^(-)的富集;此外,氢氧同位素分析表明少部分高氟矿井水的形成与蒸发作用有关。
The fluoride(F^(-))mass concentrations in many mine water samples in the Shendong mining area of Shenhua exceed the national standard(>1 mg/L),which brings some great challenges to the storage,reuse and discharge of the mine water.In order to investigate the potential sources of fluoride in the mine water and study the formation mechanism of high-fluoride mine water,81 water samples including mine water,phreatic water of unconsolidated formation of Salawusu Formation,and surface water were collected from 8 coal mines in the Shendong mining area.Their hydrogen and oxygen isotopes and main ion mass concentrations were determined.The test results show that the F^(-)mass concentration of mine water in the Shendong mining area ranges from 0.05 to 11.65 mg/L,with an average of 1.96 mg/L.51%of mine water is high-fluoride mine water.The analysis of hydrogen and oxygen isotopes shows that most of the high-fluoride mine water samples have relatively lighterδD andδ^(18)O values,moreover,theδD andδ^(18)O values decrease with the increase of the F^(-)mass concentrations in mine water samples.The analyses suggest that the mine water samples with lighterδD andδ^(18)O values are relatively old and have a long residence time in the formation.They have poor hydraulic connections with the phreatic water of unconsolidated formation and surface water and are within a relatively closed groundwater environment,leading to a stagnant runoff condition and sufficient water-rock reactions.Once the mineralogy and geochemical conditions of the aquifer are appropriate,the F of the fluoride-bearing minerals releases,resulting in the enrichment of F^(-)in the water.The correlation analysis between the hydrochemical types of mine water and the F^(-)mass concentration shows that the Na-HCO_(3)type water has the highest F^(-)mass concentration.The F^(-)mass concentrations in the Na-type mine water are obviously higher than that in the Ca-type mine water.With the increase of the Na^(+)mass concentration and the decrease of the Ca^(2+)mass concentration,the mass concentration of F^(-)increases,reflecting that the enrichment of F^(-)is mainly related to the water-rock reactions of increasing the Na^(+)mass concentration and consuming the Ca^(2+)in the mine water.The comprehensive analysis shows that the formation of high-fluoride mine water in the Shendong mining area is mainly related to the cation exchange adsorption of Ca^(2+)in the mine water for Na^(+)absorbed on the minerals.Meanwhile,under higher alkaline water environment,the OH^(-)-F^(-)anion exchange and the Ca(OH)_(2)mineral precipitation also contribute to the enrichment of F^(-)in the mine water.In addition,the hydrogen and oxygen isotope analysis indicates that the formation of a small part of high-fluoride mine water is related to evaporation.
作者
郭洋楠
杨俊哲
张政
李国庆
李庭
王雷
GUO Yangnan;YANG Junzhe;ZHANG Zheng;LI Guoqing;LI Ting;WANG Lei(Institute of Technology,Shenhua Shendong Coal Group Co.,Ltd.,CHN Energy,Shenmu 719300,China;State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,CHN Energy,Beijing 102200,China;School of Earth Resources,China University of Geosciences,Wuhan 430074,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2021年第S02期948-959,共12页
Journal of China Coal Society
基金
“煤炭开采水资源保护与利用”国家重点实验室开放基金资助项目(SHJT-17-42.18,SHJT-17-42.8)
中国地质大学(武汉)学科杰出人才基金资助项目(102-162301192664)
关键词
神东矿区
氟
矿井水
氢氧同位素
水-岩作用
Shendong mining area
fluorine
mine water
hydrogen and oxygen isotopes
water-rock reactions
