Flotation process is usually adopted to gain cleaned coal with high combustion value.Since the difference in proportion between coal particle and impurity in water,coal mine will float on the surface of the water while the impurity will percipitate at the bottom of the container.Cleaned coal is obtained after further process.In the above process,impurity can be removed and water can be recycled. PAC and PAM can function as a flocculant to improve the seperation efficience of water and impurity.