Sintesis dan pencirian Zeolit daripada abu terbang
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Date
2005
Authors
Suhaina, Ismail
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Abstract
Characterization of fly ash from one of the power plant in Malaysia has been
carried out and used for the synthesis of zeolites. The synthesis of zeolites from fly ash
appears to be one of the alternatives in the utilization of waste materials. The fly ash
samples used were very fine (min size particle was 6.17μm). From the mineralogical
studies carried out, it was found that the fly ash samples were composed of crystalline
phase - quartz, mullite and magnetite together with the amorphous phase based on
alumino silicates glass. Silica and alumina were the major component and silica
alumina ratio was 4.4 at which the ratio appears to be a suitable substrate for zeolite
synthesis. Morphologically, the sample appears to be mostly spherical with smooth
surfaces and some were cenospheres in shape. Several samples of fly ash (size ≤75
μm) undergo pre-treatment process by using acid leaching (optimum acid
concentration- 8 M HCL) to remove any deleterious iron content.
Two methods have been carried out for the synthesis of zeolites which are the
fusion method and the hydrothermal conventional method (for selected samples). The
optimum synthesis condition for fusion method was achieved at 85oC with an 8 hour
reaction time was applied to the hydrothermal conventional method. The mixture of
linde type A hydrated zeolite, hidroxy-sodalite and faujasite were found to be the
dominant type present, particularly synthesized from fusion method, and a mixture of
linde typed A dehydrated, hidroxy-sodalite and mullite were identified in some products
derived from conventional methods. Both methods of synthesis zeolites, showed that
the CEC values of synthetic zeolites were significantly higher compared to the CEC of
fly ash. CEC value for the fly ash sample was found to be 0.3meq/100g while fusion
and hydrothermal conventional method, the CEC values were found to be 13.1
meq/100g and 5.5 meq/100g respectively. Surface modification on the spherical like fly ash particles on the zeolites produced by fusion method was observed to occur by
precipitation of irregular and cubical particles. Change in the particle shape of fly ash
had an effect on the surface area. Specific surface area of the synthetic zeolite was
significantly increased over that of the raw fly ash from 3.08m2/g to 92.32m2/g.
Description
Master
Keywords
Materials and Mineral Resources Engineering , zeolite , Fly ash