Characterizing and element mapping of internal parts of a smartphone through automated and correlative microscopy

Abstract

This work used correlative and automated microscopy to have a better understanding of the internal components and structures of a smartphones. The objective is to see if there is any potential that these techniques can be of extra value for the recycling of electronic waste. Parallel slices were made out of one smartphone to study the internal structure and components of the phone. After, the same kind of smartphone was shredded and melted to study the behaviour of the material after these processing steps under the microscope. For this research, the SEM and the attached software Mineralogic by ZEISS were used to provide visual and statistical data. The system proved to be e cient and accessible in treating waste electronic material. That is to say that the components could be easily identi ed and classi ed under a speci c name. In the case of electronic waste this is either as an alloy or as a pure metal. To have a good understanding of the alloy, detailed analysis by Bruker were often necessary. Precious and critical metals were located and their internal relationships with other components was studied. Shredding showed how these compositions crumbled into smaller fractions or kept together as a whole. This helped for instance to understand how metals are discarded into waste streams during pre-processing steps as being trapped within other metal fraction, ceramics and plastics. The molten phone sections showed how the original composition of the di erent components completely changed. During crystallization, new compositions are made completely di ering from the original ones. Mineralogic in association with Bruker proved to be a valid system. However, it was suggested to segment the sample in di erent phases based on optical microscopy and BSE images. These phases could be more rapidly analysed under EDS without analysing all pixel in a pre-determined grid analysis. This suggestion was mainly made to improve the e ciency of automated microscopy on WEEE samples. Another issue to be faced in the future is the sample preparation as it is very hard to generate representative sample for this work. Combination with Ct-scans or other techniques is advised.