ABSTRACT: The tailings discharged from coal preparation processes are used to be pumped and stocked in tailings ponds for clarification. However in China, there are few tailings ponds for coal slurry. Most tailings are generally clarified in concentrators which volumes are far smaller than tailings ponds. The supernant is directly recycled to processing units and underflow is pumped to dewatering. Due to the limited settling space and periods, the clarification is very easy to interfered resulting in supernant with relative high concentration and underflow with low concentration. Because the supernant is the main resource of production water, under this case, separation units have to be ceased until the recycled supernant concentration lower than the standard. Therefore, clarification is crucial for the whole coal separation processes. In this paper, two representative clay minerals in coal slurry water, kaolinite and montmorillonite were taken as research objects. The dynamic process of surface hydration, interlayer expansion and particle dispersion of clay minerals in coal slurry water have been revealed step by step. Meanwhile, with the help of the development of computational chemistry, the matching characteristics of inorganic and organic hydrophobic regulatory agents were clarified from the molecular level. Finally, following an overview of the previous study progress so far made both within and abroad on sedimentation characteristics based on clay behaviors, the development trend of coal slurry water treatment technology is also prospected.
 

settlement of coal slurry water, clay mineral, sedimentation characteristics, swelling inhibition, molecular dynamics