Preparation of biological aerated filter media with coal fly ash and coal gangues

A novel kind of filter media has been studied using in biological aerated filter process which is produced by waste coal fly ash and coal gangues. The specific surface area and sum of braking and ware rate are viewed as the main factor for determining preparation conditions, including calcination temperature (in the range of 900°C to 1250°C), proportion of coal gangue (in the range of 0 to 25%) and soaking time (in the range of 0 to 40 min). The effects of sintering conditions on the main property parameters are researched and the reasons have been analyzed. Considered with all factors, the optimum technological conditions are chosen as follows: the calcination temperature is 1050°C; the soaking time is 10 min and the proportion of coal gangue is 5%. When at these condition, the main property parameters of the filter media in the technological conditions are 1.6 m ²/g for the specific surface area and 2.96% for sum of braking and are rate respectively. Finally, a scanning electron microscope is used for analyzing the microstructure of the filter media.