最後，將具膨脹性混燒飛灰以濕式處理製作鹼激發砂漿試體，可發現試體已無高度膨脹現象發生，確認濕式處理可有效消弭研究之兩種混燒飛灰中可反應性鋁金屬。 ;Solid Recovered Fuel (SRF) is produced from combustible waste, which includes domestic waste such as plastics, paper, and wood. Notably, some of this waste is reprocessed into SRF and contains aluminum foil material. When co-fired with coal in a Circulating Fluidized Bed (CFB) boiler, the resulting fly ash retains aluminum metal substances. Consequently, its reuse in cement-based materials leads to volume expansion phenomena.
This study carried out material property analysis on co-fired fly ash derived from domestic Circulating Fluidized Bed (CFB) boilers, investigating the expansion factor of co-fired fly ash applied to cement-based materials. The research findings reveal that the residual aluminum content in the co-fired fly ash leads to significant expansion of the specimens due to hydrogen production in an alkaline environment. In order to provide a quick identification method for boiler operators or recycling businesses to confirm the hydrogen expansion characteristics of co-fired fly ash, a rapid aluminum content screening test for co-fired fly ash has been established. This test allows effective identification of residual aluminum content in the co-fired fly ash within a 5-minute test period, even if the aluminum content is as low as 0.02%. In addition, to quantify the reactive aluminum content in co-fired fly ash, an aluminum content detection method for co-fired fly ash has been established, choosing 1.0M sodium hydroxide as the detection reagent. This method can effectively detect the presence of aluminum, even if the co-fired fly ash only contains a residual aluminum content of 0.02%.
Finally, expansive co-fired fly ash was subjected to wet treatment to produce alkali-activated mortar specimens. It was observed that the specimens no longer exhibited significant expansion, confirming that the wet treatment effectively eliminates the reactive aluminum present in the two types of co-fired fly ash studied.
