310 5 368 10 392 20 410 30 421 40 451 50 462 60 470 70 475 80 477 90 503 95 532 fbp 548 density at 15 u00b0 c g ml 0 927 rcr wt 0 353 paraffins wt 43 94 naphthenes wt 16 66 aromatics wt 39 40 nitrogen ppm basic 437 total 1207______________________________________ this example illustrates a method for preparation of fluid cracking catalyst as per the process of this invention using silicon stabilized rare earth exchanged y zeolite aluminum depleted kaolin clay prepared as per the process of example 3 normal kaolin clay alumina and ammonium polysilicate a slurry with final ph 3 4 and solid content 28 having the following composition in wt was prepared zeolite 25 alumina 30 aluminum depleted kaolin clay 20 normal kaolin clay 20 and silica 5 214 3 gm of alumina was peptized with 17 25 gm of formic acid to the peptized alumina 156 3 gm of ammonium polysilicate and 117 65 gm normal kaolin clay were added followed by addition of 109 9 gm of aluminum depleted kaolin clay in 100 gm of dm water 140 5 gm of silicon stabilized rare earth exchanged y zeolite in 200 gm dm water was ground into fine paste and added to the normal kaolin clay alumina slurry the final slurry was spray dried the microspheres were calcined and steam deactivated.