No, you can not use the Norton flattening stone to raise slurry. It is a course grit Silicon Carbide, probably about 60 grit. You will end up with slurry of that grit.
A diamond plate is more effective and cleaner way to flatten and raise slurry. Good diamond plates can be purchased inexpensively, Chef Knives to Go sells a good 400/1000 grit combo plate for $30.
Kim, so you are using .09 um Iron Oxide, not Car Pro Iron X, right?