Study on coal minerals phase transformations under different coking conditions

Abstract

The minerals in coals have a great influence on coke properties. Therefore, it is important to research the minerals phase transformations under different conditions in the coking process. X-Ray Diffraction and Mineral Quantitative Analysis Method were used to investigate blending coal minerals phase transformations under different coking conditions. The results show that with the increase of coking temperature, most of minerals contain clays and calcite changes in a certain degree. Kaolinite firstly transforms to metakaolin, then transforms to mullite, sillimanite, quartz, cristobalite and alumina. Anhydrite reacts with other minerals and makes content of itself decrease. Pyrite converts into mackinawite and iron carbon compounds, then transforms into pyrrhotite. With the increase of coking time, the species of main minerals decomposition products in blending coal coking process do not change. However, the content of quartz increases by 11.38%, the contents of cristobalite and mullite decrease by 1.52% and 8.52%, respectively.