Impact of Free Calcium Oxide Content of Fly Ash on Dust … · analysis according to the ASTM D 2013 standard.10 Ash (dry basis), CO 2 (dry basis), and sulfur contents were determined for the lignite samples, according to ASTM standards D 3174,11 D 1756,12 and D 3177.13 Equal quan-tities of fly ash (dust) from each power unit were collected every …