Experiment 42: Extracting Tantalum Metal from Capacitors

After reading some interesting notes on another chemistry blog, I found out that there was solid tantalum metal inside tantalum capacitors.  Apparently, tantalum is comparable in price to gold, but I wanted the tantalum for my element collection, not for scrap value.  Intrigued, I rummaged through my mountainous stack of scrap circuit boards to find all their tantalum capacitors.

I found around thirty tantalum caps on different boards and broke them off.  They are somewhat distinctive in appearance, but a Google search for "tantalum capacitor" also helped with identification.  The tantalum capacitors I got can be seen in the picture on the right.

To extract the tantalum, I used a hammer to lightly tap on the larger capacitors and used pliers to crush the epoxy on the smaller ones.  The tantalum inside is a somewhat-fragile sintered block, so don't go crazy wacking them, or they will break.  Each tantalum block had a small tantalum wire attached to it, and this wire was attached to the capacitor SMD solder pad.  I removed the solder pads from all the blocks I broke out of the epoxy and then placed the tantalum into a test tube for further cleaning.  I added sand and water to the test tube and shook it vigorously to abrade off the manganese dioxide electrolyte on the surface of the tantalum.

Once the tantalum was clean and dry, I ended up with twenty-five miniscule black tantalum blocks with anodized tantalum wires protruding from them.  I thought they were pretty neat, since they were quite heavy for their size, owing to tantalums density of ~16g/cc.  The wire anodization colors were also interesting and ranged from blue to green.  They weighed just about one gram total and made a really fascinating sample for my element collection.  Who knew tantalum was in every computer?