Investigation of fly ash characteristics on zeolite 4A synthesis

Akın, Süleyman Şener
There is lack of information about the relation between the candidate raw material fly ash and end product, Zeolite 4A.This study aims to fill the gap in the literature through controlled ash production experiments, characterization studies and Zeolite 4A synthesis. As a result of studies, the nucleation behaviour of the alkali fusion product obtained from fly ash was demonstrated and the most crystalline Zeolite 4A with cubic morphology were obtained from Seyitömer fly ash with alkali fusion product of Si/Al mol ratio 1,17 at the conditions, 47 °C, 12 hour aging and 90°C, 4 hour crystallization with the least sodalite impurity. It was observed that hematite and mullite content of fly ash caused differences in the alkali fusion product and Zeolite 4A. In addition, it has been observed that the hematite, mullite content and crystallinity of ash could be tuned by combustion parameters. From the Tunçbilek ash obtained from the drop tube furnace at 1000 °C, which is the poorest in mullite and hematite because of the conditions (high cooling rate and low combustion temperature), Zeolite 4A with 64,1 % crystallinity and cubic structure and minimum sodalite content was achieved under optimal synthesis conditions. Sodalite phase impurity content increased in parallel with hematite and mullite mineral content. In the synthesis product of Soma ash, katoite was obtained because of high level of calcium impurity. Finally, the ash from combustion experiments of the blend of sodium carbonate-coal-aluminum hydroxide, the synthesis of zeolite 4A was carried out under optimized conditions without the need for a fusion step and zeolite 4A was obtained with low crystallinity.


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Citation Formats
S. Ş. Akın, “Investigation of fly ash characteristics on zeolite 4A synthesis,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Micro and Nanotechnology., Middle East Technical University, 2019.