Thermal analysis of effect of concentration on WPCB powder addition as a reducing agent for nickel limonite ore reduction using TGA - DSC analysis

Waste printed circuit boards (WPCB) are a valuable kind of electronic waste with the fastest growing waste streams globally, especially in Indonesia, with a total production of 1.3 million metric tons (4.9 kg/capita). This study investigates the possibility of waste printed circuit boards (WPCB) powder obtained after pre-treated by several processes (dismantling, grinding, and magnetic separation) to be an alternative reducing agent for nickel limonitic ore reduction process. The experiment used WPCB with mixing proportions of 5, 10, and 15 wt.% under nitrogen atmospheres at 1100°C with 10°C/min heating rate for both reduction with thermal analysis instruments Thermogravimetric Analysis and Differential Scanning Calorimetry (TGA - DSC). Based on TGA - DSC analysis, WPCB successfully undergo a pyrolysis process at a temperature of 200 - 300°C, which experienced a high mass loss based on TGA results. Moreover, the DSC analysis results prove that as a concentration of WPCB in limonite ore increased, the reduction kinetics would be faster verified by decreasing the exothermic peak. Furthermore, the TGA - DSC results found that the mixture's dominating minerals were fayalite (Fe2O3) and magnetite (Fe3O4) The results of this study showed that WPCB powder performed well in the reduction of limonite ore and provide an alternative for recycling method using thermal analysis treatment. However, further study is needed to measure the optimum parameter to produce the nickel or ferronickel recovery from limonite ore.