Experimental Simulation Study of Mine Water Acidification under the Action of Pyrite

The discharge of acidic water has become an environmental issue of great concern worldwide. In order to investigate the characteristics and mechanism of acidic water induced by pyrite in sulfur-rich mines, indoor static precipitation and dynamic leaching simulation experiments were carried out under the conditions of pyrite content, rock particle size, media combination, and ambient temperature. At the same time, this paper used the gray correlation method to quantitatively analyze the influencing factors. The results showed that the degree of groundwater acidification was negatively correlated with the rock particle size and temperature and positively correlated with the pyrite content. The quantitative analysis of the effect of each factor on acid mine drainage pH was pyrite content > temperature > rock size. When considering different media conditions, the combined effect of the three media on reducing the acidification degree of mine water was limestone > gangue > coal. In addition, dynamic leaching and static soaking have different effects on the acidification of the mine water, with the latter acidifying more rapidly. It is also concluded that although pyrite enrichment was the main controlling factor affecting the acidification of mine water in nature, complexation of trivalent iron ions adsorbed in the formation was more likely to be the main causal mechanism for the rapid acidification of mine water in coal mining areas.