Dissolution properties of some fly ash fillers applying to geopolymeric materials in alkali solution

• Published in: Journal of materials science 2007-05, Vol.42 (9), p.2953-2957
• Main Authors: Mikuni, Akira, Komatsu, Ryuichi, Ikeda, Ko
• Format: Article
• Language: English
• Subjects: Ashes; Blast furnace chemistry; Blast furnace practice; Blast furnace slags; Boilers; Calcium ions; Caustic leaching; Combustion; Dissolution; Fillers; Fluidized bed combustion; Fluidized beds; Fly ash; Inductively coupled plasma; Leaching; Materials science; Organic chemistry; Pulverized coal; Separators; Sodium hydroxide; Steel industry
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-006-0530-9

Dissolution properties of three kinds of fly ash including a Pressurized Fluidized Bed Combustion (PFBC) ash from a novel type of fluidized bed combustion boiler have been studied by leaching in different concentrations of caustic soda solution up to 15 N at 25 °C and 80 °C, stirring for 1 h with liquor/solid ratio = 10. Liquors sampled by a centrifugal separator were chemically analyzed by ICP technique. A blast furnace slag was also studied for reference. Results showed that Ca2+ dissolved relatively large amount in genuine water, but no marked dissolution was detected with increasing NaOH concentrations of the leaching solution. No enhanced dissolution of Al3+ was detected for ordinary fly ashes collected from pulverized coal combustion boilers even with increasing concentrations of solution at 25 °C, whereas enhanced dissolution of Al3+ was observed at 80 °C, when 5 N was reached and more. On the contrary, appreciable increasing was noted on the dissolution of Si4+ with increasing NaOH concentrations even at 25 °C for the ordinary fly ashes and the Si4+ dissolution became enhanced at 80 °C, specifically in 5 N and more.