Recycling ceramic

"Ceramic" is a generic term. A quick look at the VXB web site revealed that (at the least) ceramic balls can be made from alumina, silicon nitride, zirconia, or tungsten carbide. All of those except the carbide could go into the average land fill, or used in ways that could abrade them (as in tumbler media). Carbide has a metallic binder (often cobalt) which probably puts it into the hazardous material category -- but it sounds like used carbide is worth something to recyclers.

Cobalt is slightly magnetic so that would be one way to separate it from other kinds of ceramic balls. Impurities could make the other types of ceramic dark or black so color probably is not a good way to distinguish different types of ceramic balls.

Out of curiosity, I checked one of my tungsten carbide inserts to see if it was conductive. Yep. However, if the silicon nitride balls are black due to an excess of silicon, they might be slightly conductive as well. I don't have any on hand to see if that's the case.
 
Tungsten carbide can be brazed with a torch and the right brazing rod/flux combo. I'm not sure about other types of ceramics. It might be possible to deposit some type of fired-on coating that can be brazed/soldered. You'd need a kiln and (possibly) plumb it to provide an oxygen-free environment for the firing. It actually might be necessary to provide a reducing atmosphere (like hydrogen) to get the desired film composition. If so, that's an "interesting" problem due to hydrogen's flammability.

I once worked for a company that made their own hybrid electronic components. They silk-screened conductor lines and resistors onto alumina (sometimes beryllia) substrates, then fired them. Some of the kilns were plumbed to produce a reducing atmosphere, and they just flared off the hot hydrogen as it came out the back end of the furnace. I bet that approach wouldn't fly today...
 
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