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MELTING AND DISSOLVING FLY ASH BY NaOH FOR THE REMOVAL OF IRON, CALCIUM AND OTHER IMPURITIES
Pages : [17] - [33]
Received : October 29, 2019; Revised January 13, 2020
Communicated by : Professor Ana Rosa Silva
Abstract
Mixture of fly ash and sodium hydroxide was calcined, which converted mullite 
the high-temperature stability phase containing silicon and aluminum oxides, and quartz into activated silica alumina phase, and they were dissolved by concentrated 
solution into soluble 
and 
The insoluble impurities including 
and 
were filtered out. Experimental results show that the optimum experimental conditions for the dissolution: temperature is 60°C, 
solution is used, liquid-solid mass ratio is 11:1, stirring time is 3h, and about 78.9% of silicon and 78.1% of aluminum are dissolved. The obtained pure silicon aluminum solution provides the raw material for preparing high-purity molecular sieves, and 
content of the prepared P type molecular sieve is only 0.25% and the 
content is only 0.066%.
Keywords
melting and dissolving of coal fly ash, removal of Fe, P molecular sieve.