Making laterite-type substrate from cat litter... possible?

[Dwarfnut]

Had to go to Wally-world today (never, never, never go there on a Sat!) with the wife and got assigned to get some more cat litter for our cats. Armed with the proper brand and size I trotted off to the pet section. Of course, she gets the fancy, smelly kind, but I noticed a huge pallet of the 'generic' cat litter for sale... no additives, just 100% natural clay.... hmmmm! I have tried 'generic' cat litter before in a planted tank under a later of sand and the plants seemed to like it. I eventually took it out as everytime I would move something in the tank, it would cloud the water really bad. I got to thinking that the laterite that is so expensive is supposed to be 100% clay also, but how do they get it to stay hard and not turn to mush!?? I was wondering if there was a way to harden the cat litter by baking it or something, much like putting a pot in a kiln? Would an over be hot enough for that anyone know how hot a kiln gets and for how long?? Does anyone know if that would work or of another way to do it??

I getting ready to set up a 20 gallon and a 75 gallon and need substrate for them. I plan to do both as planted tanks, but sure can't afford to buy that much laterite!! Anyone have other suggestions??

Thanks,
Bill C.