Edit: according to the msds the melting point for aluminum oxide is 2000°. I wonder if they use some sort of heat fusing process to make the bricks ...
Again, I think you'll find that alumina abrasives are ground and sieved to size (the numbers you get on sandpaper and grindstones, "mesh size") then are bonded together with an agent, traditionally Phenol Resin.
The only materials that can be 'fused under heat' the way ceramics sometimes are is when you go through the bisque process (aka 'low firing'). Such materials are pretty stable but kind of soft, sometimes called 'green'. This is where TV machines the parts used in the carts. Then the parts are high fired, where glass (silica) from the mix melts and truly cements the pieces together. Such materials tend to not be porous where bonded ones often are made so intentionally.
That is not all ceramic materials are the same. Some, like in Cera, are basically one piece. Others, like aluminum oxide stones and paper are small bits glued together with something.
I'm not saying it won't work or it's unsafe, just that while materials intended for use by people at the temperatures we're talking about I think that's the way to go. No matter what the e-cig guys do?
OF