Abstract

In recent years, the demand for tantalumcapacitors has been increasing due to the miniaturization ofelectronic devices. Tantalum capacitors, which use the raremetal tantalum as the capacitor element, are used in electronicdevices such as cell phones because they are smaller and have ahigher capacity than conventional capacitors. In Japan, thereare reports that minerals containing rare elements are beingextracted from discarded electronic and electrical equipment toproduce medals for the 2020 Tokyo Olympics. In Japan, manyused electrical products containing rare elements are discarded,and these metals are called urban mines. The tantalumcontained in tantalum capacitors accounts for 40% of the totalmass of the sintered material and is expected to be recycledfrom discarded products. However, tantalum capacitors arecovered with a hard mold resin ofacrylonitrile-butadiene-styrene (ABS) resin, which ischemically and physically stable. However, due to its nature,ABS resin is difficult to destroy and has not been recycled. Inthis study, hydrotalcite (HT) (Mg6Al2(OH)16CO3・MH2O) wasused to extract tantalum from the sintered tantalum capacitorby pyrolysis. HT was added to the tantalum capacitor andplaced in a metal reactor and subjected to pyrolysis at 550℃ innitrogen to determine if the sintered tantalum was susceptibleto fracture. It is presumed that the bromine gas generated fromthe ABS resin of the tantalum capacitor was trapped by the HTand the mold resin of the capacitor became residual carbon.