Moisture contents were obtained by drying
the crushed samples in a constant-temperature oven at 105 C,
and the ash contents were obtained by inserting the samples into a
constant-temperature oven maintained at 550 C. The mass of the
combustible contents were obtained from the difference between
mass of the dried samples and their ash weight. The ash was then
formed into a briquette for analysis by Rigaku ZSX X-ray Fluorescence
equipment to obtain the ash composition.