Influence of Na2CO3 on Thermal Decomposition of Waste Printed Circuit Board in Carbon Dioxide

The influence of Na2CO3on RF4-type waste printed circuit board (PCB) pyrolysis in carbon dioxide was studied with thermogravimetric analysis, and the reaction kinetics was calculated based on the Coats - Redfern method. It is shown that the weight loss process of waste PCB in carbon dioxide includes two stages. The first stage of weight loss is between 280 °C and 450 °C, at which the decomposition of epoxide resin leads to volatile materials release. The second stage of weight loss is the reaction between carbon residue and carbon dioxide between 600°C~960 °C, and carbon monoxide is formed. Addition of Na2CO3decreases the initial temperature of the second weight loss stage of waste PCB and increases the weight loss rate, which indicates the enhancement effect on gasification reaction between carbon residue and carbon dioxide. From the different mechanism function, the optimal mechanism function isf(a)=5(1-a)/4[-ln(1-a)]4and the range of activation energy is 75～135 kJ/mol.