I can't imagine those plastic ball mills, in the links, being heavy duty enough. I think they're mainly for slow grinding and polishing stones. I would think you would need at least 3/8" steel and an assortment of good sized balls. Something like Harold built. A photo of it was on the forum. I tried grinding ceramic CPU packages in a heavy duty ball mill a little bigger than Harold's and it took a good 2 hours. You need more of a crushing action than a grinding action.
We once had a large set of powered, adjustable, steel rolls, originally used for some sort of paint manufacturing. If I remember right, the 2 rolls were about 6" in diameter X 12" long. They were mounted side by side to each other, rather than one above the other. We had a hopper that fed the parts into the rolls, from the top. We mainly ran alumina ceramic, side brazed, IC packages through them. Crushed them into about 1/8" -1/4" pieces in one pass. Worked great and was fairly fast. Didn't damage the steel rolls very much. Usually, they ran most all day.
We once had a large set of powered, adjustable, steel rolls, originally used for some sort of paint manufacturing. If I remember right, the 2 rolls were about 6" in diameter X 12" long. They were mounted side by side to each other, rather than one above the other. We had a hopper that fed the parts into the rolls, from the top. We mainly ran alumina ceramic, side brazed, IC packages through them. Crushed them into about 1/8" -1/4" pieces in one pass. Worked great and was fairly fast. Didn't damage the steel rolls very much. Usually, they ran most all day.