FRLP - PRODUCCIÓN EN INVESTIGACIÓN, DESARROLLO E INNOVACIÓN

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Author: search.filters.author.Pereyra, AndreaSubject: search.filters.subject.Fly ashes

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    Phase transformation during the zeolitization of fly ashes
    (Elsevier, 2017) Monzón, Jorge; Pereyra, Andrea; Conconi, Susana; Basaldella, Elena
    The reactivity of a fly ash discarded from a thermoelectric power station was evaluated in terms of its hydrothermal conversion into NaA-containing products. The influence of ash pretreatments and the effect of changes in the synthesis mixture composition on the evolution of the solid phase toward its conversion into zeolitic materials were studied. Activation by milling was not as effective as alkaline fusion. The highest levels of fly ash reactivity were obtained by applying an alkaline fusion treatment using sodium carbonate at 800 C. It was observed that this particular ash activatiorn induces a solid reordering that generates crystalline materials identified as NaAlSiO2 polymorphs that in turn are easily transformed into zeolite structures. Synthesis conditions for ash zeolitization as high as 60% were established.
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    Improving reactivity of fly ashes towards zeolite synthesis by using alkaline fusion pretreatments
    (International Zeolite Conference, 2016) Monzón, Jorge; Pereyra, Andrea; Basaldella, Elena
    The increased demand for electricity has created the need to build large thermoelectric power plants where coal is the primary fuel used. This fact suggests the generation of significant amount of solid combustion residue. Fly ashes represent almost 70% of all coal combustion products. For this reason, different investigations are focused on developing new recycling techniques for coal fly ash [1]. This paper analyzes the effects of different pretreatments conditions, different synthesis mixture compositions and reaction times on the fly ash conversion to NaA zeolite by hydrothermal synthesis. A residual fly ash (Thermoelectric Central of San Nicolás, Buenos Aires, Argentina) with or without pretreatment (calcination and/or fusion with Na2CO3) was alkaline-treated and reacted under controlled conditions of temperature and autogenous pressure. The zeolitic phases conversion was evaluated at different reaction times by XRD and Rietvield method.