Occurrence and correlation of mercury and sulfur in Liuzhi and Zunyi coals

Two coals from different coal mines, Liuzhi (LZ) and Zunyi (ZY) in the Guizhou province, with high mercury (Hg) and sulfur (S) contents were studied in this article. Different methods were used to identify the occurrence and correlation of Hg and S in the two coals, such as, float-sink test, sequential leaching test, low temperature ashing (LTA), and also X-ray diffraction (XRD). The results show that the sulfur forms are different in the two coals. Sulfur in the LZ coal is mainly in the pyritic form and in the ZY coal in the organic form. Mercury is mainly associated with pyrite for LZ coal and with clay minerals for ZY coal. In LZ coal, mercury and sulfur have a good correlation, but in ZY coal the correlation between mercury and sulfur is not so good.