Application of Chloride Metallurgy and Corona Electrostatic Separation for Recycling Waste Multilayer Ceramic Capacitors

Electronic-waste recycling has become a global issue owing to its potential environmental pollution and rich metal resource. Waste multilayer ceramic capacitors (MLCCs), widely existing in discarded electronic devices, are rich in valuable metals such as silver (Ag) and palladium (Pd). However, how to effectively and in an environmentally friendly manner recycle waste MLCCs is seldom considered. This study developed an efficient and integrated process for recovering valuable materials from waste MLCCs by chloride metallurgy (CM) and corona electrostatic separation (CES). In CM, NH₄Cl was used as the chlorinating agent. The results demonstrated that BaTiO₃, Ag, and tin (Sn) can be chlorinated. The generated gas-phase SnCl₄ was collected in the condensing zone. BaCl₂ and AgCl were sequentially separated by leaching with water and sodium thiosulfate solution. The recovery efficiencies of Ag, Ba, and Sn could reach 99.21, 98.76, and 99.83%, respectively. The optimal CM parameters were considered to be 400 °C, 30 min, and NH₄Cl/scrap mass ratio of 4:1. Then, the residual Pd and TiO₂ were performed by CES. Pd and TiO₂ can be well separated under a voltage of 30 kV and a roll speed of 25 rpm. This study contributes to the efficient recycling of valuable resources from waste MLCCs