FCC catalyst, its preparation and use

1. A process for the preparation of a catalyst comprising the steps of:

a) preparing a slurry comprising 5 to 70 wt % clay with less than 0.1 wt % Na 2 O, 10 to 70 wt % zeolite, 1 to 35 wt % a sodium-free silica source, 1 to 50 wt % non-peptised quasi-crystalline boehmite having a (020) reflection with a full width at half height (FWHH) of 1.5° or greater than 1.5° 2θ, and 1 to 50 wt % micro-crystalline boehmite having a (020) reflection with a full width at half height (FWHH) of smaller than 1.5° 2θ , provided that the slurry does not comprise peptised quasi-crystalline boehmite, wherein the solids content of the slurry is between 10 and 30 wt %,

b) adding a monovalent acid to the slurry sufficient to obtain a pH lower than 7,

c) adjusting the pH of the slurry to a value above 3, and

d) spray drying the slurry to form particles wherein the inlet temperature of the spray dryer is between 300 to 600° C. and the outlet temperature is between about 105 to 200° C.

2. The process of claim 1 , wherein the slurry contains 5 to 50 wt % of quasi-crystalline boehmite, and 1 to 20 wt % of micro-crystalline boehmite.

3. The process of claim 1 , wherein the slurry contains 15 to 35 wt % zeolite, 10 to 50 wt % clay and 4 to 18 wt % sodium-free silicon source.

4. The process of claim 1 , wherein at step c) the pH is adjusted to between 2 and 5.

5. A catalyst composition comprising clay, zeolite, a sodium-free silica source, quasi and micro-crystalline boehmite, wherein the composition is prepared by the process of claim 1 .

6. The composition of claim 5 , wherein the catalyst comprises 1-50 wt % of quasi-crystalline boehmite, 1 to 25 wt % of micro-crystalline boehmite, 1 to 25 wt % silica, 5 to 50 wt % zeolite, and the balance clay, calculated as oxides.

7. The composition of claim 6 , wherein the catalyst comprises 3-40 wt % of quasi-crystalline boehmite, and 5-25 wt % of micro-crystalline boehmite.