Synthesis of Higher Grade Zeolites from Hopper Fly Ash

1 Synthesis of Higher Grade Zeolites from Hopper Fly Ash 

Synthesis of zeolites from fly ash by resorting to hydrothermal treatments of the (i) fly ash-NaOH mixture, in one step and the (ii) supernatant, the liquid by-product of such treatment, and NaAlOa mixture, in two steps, is well established. However, the presence of residual fly ash in such zeolites is responsible for their impurities (i.e., presence of Quartz and MuUite) and their low grade, in terms of the cation-exchange capacity and crystallinity. To overcome these issues, a novel methodology, three-step activation (TSA) of the fly ash by hydrothermal method has been developed and its details are presented in this section. It has been demonstrated that this method results in high grade polycrystalline zeolites, which 

6 Major Findings of the Three-Step Activation Technique 

---