The material world of mobile phones and co.
Display boards to visualize the occurrence and use of materials for electronic devices.
Over the past 20 years, numerous models of mobile phones and sizes of PC hard drives have become established. Despite the variety of types and assemblies, the relative proportions of materials can be considered similar.
The display board “Inside a PC hard drive” shows the material occurrence and its use using the example of a 3.5” hard drive.
Mobile phones are also made up of numerous raw materials, elements and components, as the diagram below shows.
The problematic supply basis due to monopolistic supply structures is viewed as particularly critical: platinum from Russia and South Africa; tantalum from the DR Congo; rare earths from China. Gold is sometimes mined under inhumane conditions in manual small-scale mining, where child labor cannot be ruled out. Another problem is the enormous energy expenditure for separating and processing the raw materials, which also usually requires chemical processes and thus the disposal of the chemicals.
Scientific Director: Dr. Volker Zepf
Design team: Knut Völzke, Johannes Ott
Client: WZU – Environmental Science Center of the University of Augsburg
Year of creation: 2012
The total weight of the hard drive shown (Seagate ST310211A) is 550 g. The main metals weigh around 430 g of this; the housing with lid accounts for the largest share at around 320 g. The plastics (around 10%) are used in complex material mixtures, primarily in the write head, the circuit board and as vibration protection. The rare metals are also represented with around 10% of the weight and, like the plastics, are used in complex material mixtures. The proportion of rare earths is around 4% in the form of strong neodymium-iron-boron magnets for the write head control and in the spindle drive.
In an average mobile phone, precious metals such as platinum, gold, tantalum and rare earths each contribute less than 1% to the total weight, but are essential for individual functions: the precious metals platinum and gold for contacts; tantalum for capacitors; the rare earths neodymium and praseodymium are needed for magnets in the speakers and vibration motors. The proportion of rare earths is on average 0.4 g per mobile phone.