| Summary: | 碩士 === 淡江大學 === 水資源及環境工程學系碩士班 === 97 === Municipal solid waste treated by incineration had being a tendency in many countries. The bottom ash after treated by water extraction and screened was often reused in the substitution material of asphalt concrete and road construction. However, the fine-particle below the sieve No.200 doesn’t have the value of reuse and its toxicity is low. From the preliminary experiment, it was found that 30% of Ca contained in the fine-particle bottom ash. The aim of this study was trying to transfer the fine-particle bottom ash into the feedstock of gypsum plaster.
The study were investigated the component of the fine-particle bottom ash, added H2SO4 to react with Ca into CaSO4•2H2O, and then transfer into CaSO4•0.5H2O in the oven. The particle size analyzer, X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) analysis were applied to exam the inner change before and after the transformation. The transformed fine-particle bottom ash was blended with pure semi-hydrate gypsum, the product was analyzed by the bending test, incombustibility test and toxicity characteristic leaching process (TCLP), in order to satisfy the relative standards.
The results showed that, the efficiency of transformation was 25.31%, crystal of gypsum was found by SEM. From the analysis of XRD spectrum, it was found CaSO4•2H2O can be converted into semi-hydrate gypsum in 135℃ for 4 hr. The plaster which added 40% fine-particle bottom ash (after transformed), 8% fiber and 75% water can achieve the good working ability and bending strength. In addition, the strength of bending was better than the market gypsum plaster. And the curve of incombustibility test was satisfied the standard of CNS6532.
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