A two-step acid mercury removal process for pulverized coal

A correlation predicting the effectiveness of a two-step acid wash coal cleaning protocol using sequential leaching of mercury from the coal was developed and the effectiveness of the two-step wash procedure was then determined for two bituminous coals. Increasing the hydrochloric acid concentration and temperature in the USGS four stage sequential leaching protocol increased the amount of mercury leached during the HCl step. Using these revised conditions, sequential leaching was then shown to correspond to the mercury removals achieved in the two-step wash method. Mercury removal rates of 50–70% were realized for the bituminous coals by pre-treating the coal prior to a wash with hot concentrated HCl.