ABSTRACT

Globally, waste electrical and electronic equipment is one of the fastest-growing waste sectors. Mobile phones constitute the major portion of the telecommunication e-waste category. Over the years, waste mobile phones were considered as a potential source of secondary metals. This study aims to determine the physical and chemical composition of the discarded mobile phones and to evaluate its recovery potential. The printed circuit boards from the discarded (waste) mobile phones (MPCB) were collected and samples of different sizes 3 × 3 cm, 2 mm, 1 mm, 500 µm, and 150 µm were obtained after milling and sieving. Elemental composition revealed the presence of base metals, Cu, Zn, Fe, Ni, and Pb, in higher quantities with a significant amount of precious metals Au and Ag. Amount of base metals present in different MPCB size fractions was found in the order 3 × 3 cm > 2 mm > 1 mm > 500 µm >150 µm. The amount of precious metals like Ag and Au was found to be higher in large-sized MPCB fractions. FTIR studies declared the presence of polymers like ABS, PC, and HIPs in MPCB samples. TCLP tests for toxic metals revealed that MPCBs contained high concentrations of cadmium, lead, and mercury highlighting their hazardous potential. The ultimate analysis revealed that NMF has a GCV of 12.34 MJ/kg and a volatile content of 42.25%, which can be a potential source of energy that can be recovered through the gasification or pyrolysis process. Overall, the comprehensive characterization of waste MPCBs will systematically provide a better understanding of e-waste recycling processes for beneficiation purpose and sustainable resource utilization.

Implications: A comprehensive characterization of waste mobile phone printed circuit boards for its elemental composition was performed. Mechanical treatment steps before MPCBs processing increased the exposure of metals resulting in a higher concentration of metals in acid-digested samples. The elemental analysis of MPCBs revealed that MPCBs possessed significant quantities of base and precious metals. The amount of precious metals like Ag and Au was also found in higher ranges in large-sized MPCB fractions, which elucidated fact to be considered in the pre-treatment process for metal recoveries. The high content of base and precious metals in waste mobile phones displayed their economic potential in the market. This new source may compensate for the escalating global demand for gold and silver. Results from the study indicated that MPCBs can serve as an excellent secondary source for various metals and as an efficient alternative fuel.

摘要

在全球范围内，废弃电子电气设备是增长最快的废弃物部门之一。手机构成了电信电子垃圾类别的主要部分。多年来，废弃手机被认为是二次金属的潜在来源。本研究旨在确定废弃手机的理化成分并评估其回收潜力。收集废弃（废）手机（MPCB）的印刷电路板，研磨和筛分后获得3×3 cm、2 mm、1 mm、500 μm和150 μm不同尺寸的样品。元素组成表明，贱金属 Cu、Zn、Fe、Ni 和 Pb 的存在量较高，还有大量的贵金属 Au 和 Ag。发现存在于不同 MPCB 尺寸部分中的贱金属数量为 3 × 3 cm > 2 mm > 1 mm > 500 µm >150 µm。发现大尺寸 MPCB 馏分中 Ag 和 Au 等贵金属的含量更高。FTIR 研究表明 MPCB 样品中存在聚合物，如 ABS、PC 和 HIP。有毒金属的 TCLP 测试显示 MPCB 含有高浓度的镉、铅和汞，突出了它们的潜在危险。最终分析表明，NMF 的 GCV 为 12.34 MJ/kg，挥发分含量为 42.25%，是一种潜在的能源，可以通过气化或热解过程进行回收。总体，

影响：对废弃手机印刷电路板的元素组成进行了综合表征。MPCBs 加工之前的机械处理步骤增加了金属的暴露，导致酸消化样品中金属的浓度更高。MPCBs 的元素分析表明 MPCBs 拥有大量的贱金属和贵金属。在大尺寸 MPCB 馏分中也发现 Ag 和 Au 等贵金属的含量范围更大，这说明了在金属回收的预处理过程中要考虑的事实。废旧手机中贱金属和贵金属含量高，显示出其市场经济潜力。这一新来源可能会弥补全球对黄金和白银不断增长的需求。