Influence and Effect of Pyrolysis with Additives in Tantalum Capacitors

Abstract

In recent years, the demand for tantalum capacitors has been increasing due to the miniaturization of electronic devices. Tantalum capacitors, which use the rare metal tantalum as the capacitor element, are used in electronic devices such as cell phones because they are smaller and have a higher capacity than conventional capacitors. In Japan, there are reports that minerals containing rare elements are being extracted from discarded electronic and electrical equipment to produce medals for the 2020 Tokyo Olympics. In Japan, many used electrical products containing rare elements are discarded, and these metals are called urban mines. The tantalum contained in tantalum capacitors accounts for 40% of the total mass of the sintered material and is expected to be recycled from discarded products. However, tantalum capacitors are covered with a hard mold resin of acrylonitrile-butadiene-styrene (ABS) resin, which is chemically and physically stable. However, due to its nature, ABS resin is difficult to destroy and has not been recycled. In this study, hydrotalcite (HT) (Mg6Al2(OH)16CO3・MH2O) was used to extract tantalum from the sintered tantalum capacitor by pyrolysis. HT was added to the tantalum capacitor and placed in a metal reactor and subjected to pyrolysis at 550℃ in nitrogen to determine if the sintered tantalum was susceptible to fracture. It is presumed that the bromine gas generated from the ABS resin of the tantalum capacitor was trapped by the HT and the mold resin of the capacitor became residual carbon.