Some are collected and sent to developing countries, often being
burnt and recycled inappropriately. Others end up at municipal landfills
here and become hazardous waste.
But if five former students of
the American University of Sharjah have their way, the unwanted devices
will be recycled and valuable metals such as copper, gold, silver and
palladium extracted.
The team spent one academic year – from
September 2011 to May 2012 – developing a plan for how to do this as
part of a project required for their chemical engineering degree. The
effort was overseen by Professor Taleb Ibrahim at the university.
The
team are focusing their efforts on printed circuit boards (PCBs), thin
plates composed mainly of copper, glass fibres and epoxy resins, on
which chips and other electronic components are soldered.
“In today’s world, they form the backbone of any electronic device,” said Said Nusri, 22, one of the five team members.
Besides
copper, the boards consist of a host of other metals, plastics and
ceramics. The metals and non-metals are stuck together by epoxy resin
and this makes them difficult to recycle.
Most countries in the
world, including the UAE, lack the sophisticated infrastructure to do
so, said Yousef Chehade, 22, who came up with the idea for the project.
Considering
the affluence of the UAE’s population and the short lifespan of
electronic gadgets here, the UAE needs to develop capabilities to deal
with the issue locally, he said.
“We have many recycling initiatives here but there is a gap when it comes to e-waste recycling,” he said.
The other members of the team are Hisham Alayan, Ameer Siddique and Naveena Sadavisam.
The
students’ first step was to determine which metals contained in e-waste
would be the most abundant and most economical to extract. They found
that copper, gold, silver and palladium – used in electronics, dentistry
and jewellery – would be the most suitable for extraction. The team
then devised a process to recycle PCBs.
First, the devices need
to be broken down into small pieces, said Mr Alayan, 21. After
experimenting in the lab with different grinders and crushers, the team
found that the optimum size of the crushed articles is less than one
centimetre. Then, through the use of electrostatic separation
technologies, the metallic parts can be separated from the non-metallic
ones.
The team have outlined chemical processes through which the
target metals can be extracted. Through the use of certain chemicals
such as sulphuric acid, nitric acid, and aqua regia, a mixture of nitric
and hydrochloric acid, the target metals can be dissolved and then
selectively extracted with high purity.
The technique is already
in use in the mining industry, though the students have modified it to
work for their recycling application.
“We proved it works in different industries and proposed a theoretical design of how it can suit our needs,” said Mr Chehade.
The
team have calculated that the method can be used to obtain 24 kilograms
of copper, 44 grams of gold, 18 grams of silver and 10 grams of
palladium from every 125 kg of PCBs.
The concept is yet to be
tested in real-life and the team are willing to continue the work to
make it a reality. Mr Chehade, for example, has already set up his own
company Sharjah, Ecyclex, which will focus on recycling.
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