Since I wanted more fine grade copper powder but didn’t want to deal with the cost/quantity of ordering online I decided to make my own. The idea is fairly simple: dissolve a chunk of copper then introduce a source of iron. The iron will knock the copper out of solution and you’ll end up with a nice copper powder. In theory, of course.
In practice this ended up being somewhat of a pain. Partly because I don’t have access to a real chemistry lab so I instead did the work sitting outside on concrete.
In the above picture, the container has a piece of copper pipe (roughly 0.75″ by 0.75″) and ferric chloride. The container in the picture below has an earlier solution of ferric chloride that had already reacted with the copper. You can see small pieces of copper at the bottom that were once a part of the steel wool.
Trying to drain off the excess liquid of the second container to get at the copper was more annoying than I expected. I didn’t have any good substance handy to wash off the residue so most of the copper stuck together in a black mess. Unfortunately it seems I didn’t take pictures of what it looked like in the end, but just imagine small copper-colored pieces of steel wool in a clump.
It’s worth noting that the copper didn’t just precipitate to uniform particles. It replaced the top layers of the steel wool – which makes sense because it is the iron after all which is knocking the copper out of the solution. Thicker pieces of steel wool had enough iron left over that a magnet could still drag them around whereas the finer grade steel wool became more like copper and less like iron (no response to the magnet).