Electronic waste is one of the fastest-growing waste streams. The content of this waste has critical importance for the development or adoption of new recycling techniques and safe waste management practices. In this study, printed circuit boards and screens of three different types of electronic wastes, such as old mobile phones, smartphones, and laptops were characterized for their heavy metal, precious metal, and rare earth element contents. Three different digestion methods were applied to the samples prior to ICP-OES analysis. Results showed that Cu, Fe, Zn, Ni, Pb, and Al were found to be the main heavy metals in all samples. Nd, Ag, and Au were found as the major precious metals, followed by Pt, La, Dy, Pr, and Ce in the rare earth element category. The contents indicated that there is an urgent need to develop recycling techniques for the recovery of these valuable materials. When the digestion methods were compared to each other, it was found that different methods performed better on different types of metals. U.S.EPA.3050B is advised for Nd, Pd, Pr, Ag, Dy, Pt, Mn, Ce, Cd, Cr, Co, Al, Pb, while U.S.EPA.3051A performed better for Au, Mo, Zn, Cu, and Ni, and MMDM for La.

Graphic abstract

电子废物是增长最快的废物流之一。这些废物的含量对于开发或采用新的回收技术和安全的废物管理做法至关重要。在这项研究中，对三种不同类型电子废物（例如旧手机，智能手机和笔记本电脑）的印刷电路板和屏幕进行了表征，以其重金属，贵金属和稀土元素的含量为特征。在ICP-OES分析之前，对样品采用了三种不同的消解方法。结果表明，铜，铁，锌，镍，铅和铝是所有样品中的主要重金属。发现Nd，Ag和Au是主要的贵金属，其次是稀土元素类别的Pt，La，Dy，Pr和Ce。内容表明，迫切需要开发回收这些有价值的材料的回收技术。将消解方法相互比较时，发现不同的方法对不同类型的金属表现更好。建议使用USEPA.3050B的Nd，Pd，Pr，Ag，Dy，Pt，Mn，Ce，Cd，Cr，Co，Al，Pb，而USEPA.3051A的Au，Mo，Zn，Cu和Ni表现更好。和MMDM for La。

图形摘要