硫化金属矿开采废石堆放对水环境的影响机理及对潜在治理措施的启示意义  

EFFECT AND MECHANISM OF WASTE ROCK STACKING DURING SULFIDE METAL DEPOSIT MINING ON WATER ENVIRONMENT AND IMPLICATION FOR TREATMENT MEASURES

作　　者：龙吟 黄天明[1,2] 张芬 马宝强 马高高 韩振华 张路青[1,2] LONG Yin;HUANG Tianming;ZHANG Fen;MA Baoqiang;MA Gaogao;HAN Zhenhua;ZHANG Luqing(Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Gansu Academy of Eco-environmental Sciences,Lanzhou 730020,China;Lanzhou Mineral Exploration Institute,Gansu Provincial Nonferrous Metal Geological Exploration Bureau,Lanzhou 730046,China)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院页岩气与地质工程重点实验室,北京100029 [2]中国科学院大学,地球与行星科学学院,北京100049 [3]甘肃省生态环境科学设计研究院,兰州730020 [4]甘肃省有色金属地质勘查局兰州矿产勘查院,兰州730046

出　　处：《工程地质学报》2022年第3期874-883,共10页Journal of Engineering Geology

基　　金：第2次青藏科考项目(资助号:2019QZKK0904);国家自然科学基金(资助号:41877207,42172277)。

摘　　要：金属硫化物矿山的废石堆场受降水淋滤影响而发生硫化物氧化,产生硫酸并释放重金属,因此采矿工程产生的废石是水污染不可忽视的来源。前人关于金属硫化矿物氧化的机理研究大多集中在单一矿物的室内实验,与野外情况匹配度较低。本研究从岩样(矿石和废石)、水样(河水、地下水、废弃尾矿库渗滤液)的水化学、微量元素和锶同位素等方面,分析某铅锌矿废石堆场对水环境的影响,并讨论其产生的化学组分在野外环境中的变化规律及机理。研究结果显示,金属硫化物氧化造成了河水酸化,pH低至2.38,SO_(4)^(2-)高达9421 mg·L^(-1),同时微量元素中Zn、Pb、Ni、Mn、Cd质量浓度远超饮用水限值,如Zn达到了582 mg·L^(-1)(饮用水限值为1 mg·L^(-1)),且浓度与pH负相关。河水酸化的主因是黄铁矿、磁黄铁矿的氧化作用,并贡献了河水中大部分的SO_(4)^(2-)。闪锌矿等矿物在贡献了河水中少部分SO_(4)^(2-)的同时,也是重金属元素的主要来源。地下水离子浓度较河水低,pH在中性左右。虽然主要是受到侧向山体地下水补给稀释,但碳酸盐和硅酸盐对酸起到的中和作用对酸性水的治理有很大启示价值。以上机理的认识对于废石对水土环境污染的防治具有重要意义。The metal sulfide oxidation in the waste rock results in a serious exceeding standard of acidity,SO_(4)^(2-)and heavy metals in surface water and groundwater.Previous studies on the oxidation mechanism of metal sulfide mostly focus on the laboratory experiment of a single mineral.However,the field situation is complex and inconsistent with the experiment.This paper analyzes the composition of rock samples(ore and waste rock)and hydrochemistry,trace elements,and;Sr/;Sr in water samples from river,groundwater,and leachate of abandoned tailings pond.The paper discusses the influence and mechanisms of a lead-zinc mine waste rock on the actual water environment.The results show that the oxidation of metal sulfide caused serious pollution to the water environment.The river water is acidified,where the pH is as low as 2.38,the concentration of SO_(4)^(2-)and Zn,Pb,Ni,Mn,and Cd exceed the drinking water limit most seriously.The concentration is negatively correlated with pH.The main cause of river acidification is the oxidation of pyrite and pyrrhotite.They contribute most of SO_(4)^(2-)to the river.The sphalerite not only contributes a part of SO_(4)^(2-)to the river,but also is the main source of heavy metals.The ion concentrations in groundwater are lower than that of river water,and the pH is neutral.The pH of groundwater is higher than that of river water,which is mainly due to the dilution of groundwater in lateral mountains.The neutralization effect of silicate and carbonate on acid in the process of river water flow has great enlightenment value for the treatment of acid water.The understanding of the mechanism is of great significance for the prevention and control of waste rock pollution to water and soil environment.This study is of great significance for the prevention and control of waste rock on water pollution.

关 键 词：废石 水环境污染 野外尺度 酸性矿山废水防治 

分 类 号：P641.69[天文地球—地质矿产勘探]