Powder Recycling Technology from Ceramic Capacitors via Chemothermal Pulverization

Abstract

Recycling multilayer ceramic capacitors (MLCCs) is a significant challenge, despite their expanding market. This study aimed to develop a technology for recycling waste MLCCs into functional ceramic raw materials by utilizing a chemothermal pulverization (also referred to as “disintegration”) phenomenon, where ceramics are decomposed into fine particles through heat treatment in an ammonia atmosphere containing a small amount of air. MLCCs were pre-crushed to approximately 100 μm and then heat-treated at 1000°C in a mixed atmosphere of ammonia and air. A ceramic sintered body was fabricated from the resulting recycled powder, and its microstructure and dielectric properties were evaluated. The disintegration treatment successfully pulverized the MLCCs into amoeba-shaped fine particles of approximately 1 μm. The internal Ni electrodes also reacted, resulting in NiO being present in the recycled sintered body. Although the densification was insufficient, with a relative density of 71%, this recycled ceramic exhibited a high relative permittivity exceeding 1000. These results indicate that the disintegration method has the potential to be an effective recycling technology for waste MLCCs.