Effect of Ammonium Salt on the Adsorption Behavior and Surface Characteristics of Sub-Bituminous Coal and Silica

[Image: see text] Ammonium salt is a common collector in coal reverse flotation. This study compared the difference of adsorption behavior on ammonium salt Lilaflot D817M between sub-bituminous coal and silica as well as the surface characteristic change after being processed by ammonium salt. The results indicate that the adsorption capacity of sub-bituminous coal is always higher than that of silica under different experimental conditions, such as different initial concentrations of ammonium salt, different adsorption times, different concentrations of the depressant dextrin, and different pH values. Ammonium salt could increase the isoelectric point of both silica and sub-bituminous coal greatly. However, the hydrophobicity of silica enhances much more significantly than that of sub-bituminous coal after being treated by Lilaflot D817M. This indicates that the surface wettability change degrees of sub-bituminous coal and silica after being treated by ammonium salt are not proportional to the adsorption capacity because of their different surface structures. The reverse flotation test result shows that 2 kg/t Lilaflot D817M dosage could help obtain relatively good flotation indexes.