Table 2.

Room-temperature Mössbauer parameters for as-received and acetylene-treated coal fly ash samples

	Values
As-received	SX1_U	SX2_U	SX3_U	D1_U	D2_U
Bhf (T)	49.0	51.6	44.2	-	-
δ (mm/s)	0.40	0.45	0.59	0.45	0.79
ΔEQ (mm/s)	−0.02	−0.13	−0.01	0.95	2.33
Area (%)	21	18	27	23	11
Treated	SX1_T	D1_T	D2_T
Bhf (t)	20.5	-	-
δ (mm/s)	0.29	0.43	1.02
ΔEQ (mm/s)	−0.003	0.41	2.15
Area (%)	49	21	30

The as-received sample showed that the total population of the oxides is 66% and 34% is attributed to silicates. After treatment, a decrease in the area fraction of 17% was observed for the oxides with a corresponding increase in the silicates.