Study On Synthesis Of Zeolites With Circulating Fluidized-bed(CFB) Fly Ash And Treatment Of Phenol Wastewater

Fly ash is a kind of granule material by combustion, which mostly comes from the coal-fire power plant. Because of cumulation for long time, fly ash occupies large space and pollutes the environment on which people living. Owing to being discharged at random, human health has been greatly harmed by fly ash.At present, the utilizing of fly ash focuses on the fields of construction and agriculture. The technological level and the economical benefit is poor.This paper studied on synthesis of zeolite with circulating fluidized-bed fly ash through the traditional hydrothermal method, exploring for the feasibility and superiority of CFB fly ash. The CFB fly ash is an active material of zeolite synthesis, including little crysal phase. So that we have no use for pretreating it by baking at a high temperature.The effects of different conditions of composition of raw materials, crystallizing time, NaOH concentration, temperature, crystallization and shape of synthetic zeolites have been investigated for the traditional hydrothermal condition. NaOH concentration has a great impact on the crystal grade of synthetic zeolite via XRD diffraction technique characterization. The relative crystallization of X zeolite is up to 60% , when the NaOH concentration is 3.00mol/L and the crystallizing time is 14h. As time passed, the relative crystallization will be improved. But the mixed zeolites will be produced at the same time. And when the NaOH concentration is 3.30mol/L, P zeolite will be produced. When SiO₂/ Al₂O₃ is 3.7, the type of zeolite will be transformed into P zeolite.In addition, the paper studied the adsorption effect of the synthetic zeolites on treating with the phenol wastewater and summarized the rule of environment influences, such as the quantity ,absorbing time and pH.This experiment tried to utilize different concentration of sodium hydroxide to modify the synthetic zeolites. The modified synthetic zeolites have a good effect on treating with the phenol wastewater. The results show that when the concentration of sodium hydroxide is 0.2 mol/L, the 79% of phenol can be removed from wastewater , and the framework structure of zeolites will not be destroyed essentially. When the quantity of zeolites is 1.5g, pH is 6-8, the time of absorbing is 30 min, the temperature is between 25 and 30℃, the removal rate of dealing with the phenol waste water is preferably. After regeneration by high-temperature calcinations in 200℃, the recovery rates of zeolites is more than 90%.Not only it can solve problems of occupying land and environment pollution caused by fly ash throwed into field, but also can deal with the phenol waste water. The technology of waste water treatment by fly ash waste recycle utilization has higher economic and social benefit.