Alow-cost Zeolite From Coal Fly Ash For Sr And Cs Removal From Polluted Seawater

Most of the studies conducted on zeolite synthesis using China fly ash are performed on small laboratory scale.Therefore,production of zeolites on an industrial/pilot plant scale would,in addition to producing a valuable product,help abating the pollution caused by the disposal of fly ash in the country.This research focused on the investigation of the scale-up opportunity of zeolite synthesis from China fly ashes with the view of understanding the effects of some reactor and operational parameters on the quality of the zeolite produced.Different types of zeolites(Zeolite N-L,Zeolite Na-P1,Sodalite,and Analcime)were synthesised via two different routes in this study:(1)a two stage hydrothermal synthesis method different types of zeolites(Zeolite N-L,Zeolite Na-P1,Sodalite,and Analcime)and(2)fusion prior to hydrothermal synthesis(different types of zeolite).The synthesis variables evaluated in this study were the effect of impeller and agitation rates during the aging step of different types of zeolites(Zeolite N-L,Zeolite Na-P1,Sodalite,and Analcime).The effect of fly ash composition and solvents(artificial sea water sources)on the phase of both different types of zeolites(Zeolite N-L,Zeolite Na-P1,Sodalite,Analcime)and the effect of the hydrothermal reaction time during the synthesis of different types of zeolites using low amorphous phase fly ash i.e.aging time(12 hours)and hydrothermal treatment time(12 hours)at different temperature.The raw materials(fly ashes from Da Tang power stations)and the synthesised zeolite product were characterised chemically,mineralogically and morphologically by X-ray fluorescence spectrometry,X-ray powder diffraction and scanning electron microscopy as well as Atomic Absorption Spectrometry.The multi-elemental analysis of the synthesis solution and the solvents(Sr/Cs)used in this study.The experimental results confirmed that the phase purity of extraordinary kinds of zeolite was strongly affected by means of agitation used at some stage in the each phases of aging step of the synthesis.Therefore,the effective zeolitisation of fly ash on a large scale would assist to mitigate the depletion of resources and environmental problems caused by the disposal of fly ash.