Preparation of NaY zeolite
1 part (by mass) 45e75 mm (by sieve fraction) kaolin clay was
mixed with 1.5 parts (by mass) of 40 wt % aqueous NaOH solution
and the mixture was heated at 850 C for 3 h in a furnace to get
fused kaolin. The fused kaolin was then milled to get fused kaolin in
powder form. 50 g of the prepared kaolin and 63 g of sodium sili-
cate were dispersed in 500 ml of deionized water by stirring at
50 C for 1 h giving a slurry of approximate pH 13.3. The slurry was
aged at 50 C for 24 h under static conditions in a polypropylene
bottle, and then crystallized at 100 C for 48 h. The solid was
recovered by filtration, washed with deionized water and dried in
an oven at 100 C for 16 h. Finally, the dried powder was calcined in
air at 500 C for 1 h.