Interfacial and Mechanical Property Analysis of Waste Printed Circuit Boards Subject to Thermal Shock

• Published in: Journal of the Air & Waste Management Association (1995) Vol. 60; no. 2; pp. 229 - 236
• Main Authors: Li, Jinhui, Duan, Huabo, Yu, Keli, Wang, Siting
• Format: Journal Article
• Language: English
• Published: Pittsburgh, PA Taylor & Francis Group 01.02.2010; Air & Waste Management Association; Air and Waste Management Association; Taylor & Francis Ltd
• Subjects: Applied sciences; Atmospheric pressure; Chemical engineering; China; Circuit printing; Cross-Linking Reagents; Cutting tools; Developing countries; Efficiency; Electronic waste; Electronics; Environmental aspects; Environmental impact; Environmental Pollutants - analysis; Epoxy resins; Exact sciences and technology; Flame Retardants - analysis; Grinding; Hot Temperature; Industrial Waste - analysis; Industrialized nations; LDCs; Mass spectrometry; Mechanical properties; Methods; Microcomputers; Microscopy, Electron, Scanning; Noise pollution; Polychlorinated Biphenyls - analysis; Printed circuit boards; Printed circuits; Pyrolysis; Recycling (Waste, etc.); Refuse Disposal - methods; Solid-solid systems; Stress analysis (Engineering); Studies; Tensile Strength; Testing; Thermal properties; Thermal stresses; Thermodynamics; Waste analysis; China; Pyrolysis; Dust; Under vacuum; Shear; Crushing; Thermogravimetry; Crusher; Mechanical properties; Spacing; Electronic scrap; Handling
• ISSN: 1096-2247; 2162-2906
• DOI: 10.3155/1047-3289.60.2.229

Waste printed circuit boards (PCBs) are the focal points for handling electric and electronic waste. In this paper, a thermal shock method was used to pretreat waste PCBs for the improvement of crushing performance. The influence of the thermal shock process on interfacial modification and mechanical property attenuation of PCB waste was studied. The appearance and layer spacing of the basal plane began to change slightly when the temperature reached 200 °C. By 250 °C, apparent bulging, cracking, and delamination were observed. However, pyrolysis of PCBs occurred when the temperature reached 275 °C, where PCBs were carbonized. The thermogravimetric analysis of PCB particles under vacuum showed that 270 °C was the starting point of pyrolysis. The tensile and impact strength of PCBs were reduced as shock temperature rose gradually, with a reduction by 2.6 and 16.5%, respectively, at 250 °C from its unheated strength. The PCBs that were heated to 250 °C achieved 100% liberation, increasing linearly from 13.6% for unheated PCBs through a single-level shear-crusher (2-mm mesh) and resulting in an obvious reduction of 9.5% (dB) in dust and noise at 250 °C. These parameters could be helpful for establishing the operational setup for industrial-scale facilities with the aim of achieving a compact process and a highly efficient recovery for waste PCBs compared with those of the traditional combination mechanical technologies.