I've worked in the catalysts scrap industry. sortof, it's one of my many roles.
My company bought Engelhard, which was THE precious metal company - most of the gold bullion in ft Knox was cast and stamped by Engelhard, and Mr Engelhard himself was the inspiration for the Bond villain Goldfinger.
With their interest in precious metals, and precious metals' value in catalysts, they became a major catalyst company and actually invented the Pt/Pd 3-way catalyst that's used in cars today (much of the original R&D done in the building I work in every day!)
My role covers all of our high temp processing of solids, which includes LOTS of different things, one of which is the melting process for reclaiming the precious metals (PM) from the catalytic converters.
When you sell the cats to metal scrappers, they get piled together. Then a precious metal company bids on them based on expected weight, usually taking samples. Sometime theyre bidding on the whole cut cats or sometimes just the removed and ground down PM coated ceramic powder. You take a sample or a few samples of a giant 1ton bag, make a best guess of the overall average composition and pay a precious metal scrap price based on that.
Then, if not ground already, the ceramic honeyomb gets cut out and ground. Then comes the cool part - it goes into an enormous electric arc furnace which is constantly blasting these massive lightingbolts of power to heat it up enough to actually melt not just the metal but the ceramic too. that's hot. Cordierite (the ceramic) doesnt melt til 2700F, gas burners dont easily get that hot, which is why the electric arc (jet fuel can't even melt steel beams!)
But then, like oil and water, because the ceramic and metal are diffrent densities, the metal sinks to the bottom and can be drawn out of the bottom of the tub and the molten cordierite off the top. Wild!
The stuff is so valuable that even the cutting floor scraps are a few million a year - there's similar stories of the floor matts in jewelers workshops (we reclaim metals from those too) and stories of guys who smuggled out thousands of dollars in dust on their clothes (and then tried to sell it... but you know who buys precious metals? THE PEOPLE YOU STOLE IT FROM, DIPSHITS)
The security is super tight, even the truckers have to get screened on entry and exit, no guns on site ever except the guards, it's funny the site has all these negative ads on google maps from angry truckers like "these guys dont trust the truckers, won't let us carry - i've got a liscence!" cuz they have little or no clue the value in that place...
But it's actually a funny lifecycle for that product line for us. We start out mining the clay in GA that gets sold to companies who make the ceramic honeycombs, then we buy the honeycombs back and coat them to sell to auto muffler manufacturers, and then at the end of life we buy em back again to reclaim the PM. So we sell the same product basically 3 times at different steps of it's manufacture.