Comparative study on evaluation methods of accurate acid production potential of coal gangue

In order to prevent major acid drainage pollution accidents, this study aims to improve the accuracy of acid production potential evaluation of mine rocks in the prediction of acid drainage. Specifically, this paper introduced existing calculation methods of acid-producing potential, and then determined the acid-producing mineral contents in some sulfur minerals and coal gangue samples by three-step sequential extraction method, which is then compared with the traditional method of calculating the maximum acid-producing potential by measuring total sulfur. Results show that: 1) the acid-producing potential of coal gangue is dependent on the mass percentage content of each acid-producing sulfur and the corresponding unit acid value; 2) except for sample SC, the acid-producing potential calculated by acid-producing sulfur content is lower than(with different degrees) the acid-producing potential predicted by total sulfur. The sulfur in the sample SC is mainly arsenopyrite sulfur, which has a higher acid value per unit than pyrite sulfur, resulting in a higher acid potential calculated by SC sample than predicted by total sulfur; 3) the three-step sequential extraction is suitable for samples with iron and copper sulfides as the main sulfur minerals; 4) when other sulfide components increase and blank samples are unevenly mixed, the results will be disturbed to some extent. This research provides evidences to justify the evaluation of accurate acid production potential of coal gangue in mining area.