Characteristics of leaching of heavy metals from low-sulfur coal gangue under different conditions

Chang Li,Chunlu Jiang,Liugen Zheng,Xing Chen,Shuaishuai Ding

doi:10.1007/s40789-021-00416-6

Chang Li, Chunlu Jiang + Show 3 more

Open Access

https://doi.org/10.1007/s40789-021-00416-6

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Abstract

Coal gangue is the main pollution source of mining areas. When coal gangue is stacked and recycled, the heavy metal elements contained in it are released by natural weathering and leaching, which causes damage to the surrounding ecological environment. In this study, the leaching and precipitation characteristics of heavy metals in low-sulfur coal gangue under different environmental conditions were simulated by indoor dynamic leaching experiments, which provided a theoretical basis for environmental restoration of the mining area. The conclusions are as follows: higher heavy metal content in low-sulfur coal gangue is associated with greater, leaching of heavy metals; acidic conditions promote the release of heavy metals in low-sulfur coal gangue; and more precipitation is associated with better release of heavy metals from the low-sulfur coal gangue.

Highlights

Coal gangue is an industrial solid waste inevitably produced in coal mining and coal washing, and its emissions account for approximately 10%–15% of coal production (Zhou et al 2014a, b)
The leaching and precipitation characteristics of heavy metals in low-sulfur coal gangue under different environmental conditions were simulated by indoor dynamic leaching experiments, which provided a theoretical basis for environmental restoration of the mining area
The conclusions are as follows: higher heavy metal content in low-sulfur coal gangue is associated with greater, leaching of heavy metals; acidic conditions promote the release of heavy metals in low-sulfur coal gangue; and more precipitation is associated with better release of heavy metals from the low-sulfur coal gangue

Summary

Introduction

Coal gangue is an industrial solid waste inevitably produced in coal mining and coal washing, and its emissions account for approximately 10%–15% of coal production (Zhou et al 2014a, b). Through indoor leaching simulation experiments, heavy metal pollution caused by coal gangue piles in the Jiaozuo mining area is studied. With the leaching of precipitation, most of the harmful heavy metals migrate into the soil under the coal gangue hill and undergo transformation, where they are retained in more stable forms such as secondary ferric minerals (Lin et al 1997). Because of the characteristics of heavy metal leaching of low-sulfur coal gangue is not yet clear, coal gangue samples of the large coal gangue hill in the Linhuan mining area of Huaibei are selected as the research objects, and an indoor leaching experiment is carried out with these samples. This study choose different weathering years, type of coal gangue and experimental conditions, are used to simulate the effects of the release of heavy metals in the ecological environment under natural conditions. The objectives of this study: (1) to reveal influence of heavy metal content in low-sulfur coal gangue on its leaching effect, (2) to identify leaching characteristics of heavy metals in low-sulfur coal gangue in natural environment, (3) to provide suggestion for the management and comprehensive utilization for coal gangue

Sampling and preprocessing

Leaching experiments

Detection of heavy metal content in leachate

Calculation of leaching rate

Contents of heavy metals in low-sulfur coal gangue

Conclusions