Wonder how much cost and effort, and how many devices, are required to salvage the metals needed...do folks even have specific recycling centers for this any more or was it not cost effective?
If you are set up to process in quantity, the average content “per ton of boards” is the same as high grade ore. Especially if you are collecting all the metals, lead, copper, Palladium, silver, gold...
I’m actually on a project to do this right now using a flail crusher and a water/gravity shaker table system.