Background

Wastes of Electrical Electronic Equipment (WEEE or “electronic wastes”) belongs to the fastest growing waste stream in the world, with an increase from 33.8 million metric tonnes (Mt) in 2010 to 41.8 Mt in 2014 and an amount of about 50 Mt in 2018. The main driving forces of such a trend are explained by the increase of the world population, the rapid socio-economic development with facilitated access to modern technologies, the change in consumer patterns and the rapid technological advancement (consumers upgrade their mobile phones after about 2 years in US and EU).

Each European citizen is annually producing around 16.6kg of WEEE and according to European Union estimations this amount will increase to 24kgpa up to 2020.

These solid wastes are rich in precious ‘critical’ and of ‘strategic importance’ metals and elements and in many occasions their content in the abovementioned constituents is much higher than that of the natural ores. Many if the contained metals in electronic wastes are at the same time posing a threat to the natural environment, given that the landfilling of electronic wastes is today common practice for many countries. Recently, a new term has been introduced ‘urban mining’ in order to express the importance of the treatment and exploitation of useful materials from WEEE and includes the development of best practices for the collection, transportation, recycling and recovery of useful metals. Thus the wastes may turn into secondary products with economic value with a parallel target the perseverance of natural resources.

In this mindset, the progressive development of circular economy is today a global priority with main targets the highest possible reduction of wastes, the prevention of environmental consequences and the increase of material exploitation in further production cycles. A typical circular economy scheme for WEEE includes the wastes collection, their treatment, the materials recovery, the redistribution in the market or/and the production of secondary materials and finally the commercial distribution of new electric – electronic or other materials.

Printed Circuit Boards (PCB) are economically the most important part of WEEE. Devices such as mobile phones, PCs, GPS, routers and printers and other electronic products contain one or more PCB. The overall quantity of metals in PCB reaches up to 30%.