E-WASTE (CELL PHONE) TREATMENT BY THERMAL PLASMA TECHNIQUE
B.Ruj1*, J.S. Chang2
1 CSIR-Central Mechanical Engineering Research Institute (CMERI), Durgapur-713209, West Bengal, INDIA
2 Department of Engineering Physics, McMaster University, Hamilton, CANADA*e.mail: biswajitruj@yahoo.co.in ; bruj@cmeri.res.in
Phone: +91-343-6452156; Fax: +91-343-2544567

Abstract
Cell phone ia an indispensable service facilatotor. But its disposal is a problematic. Cell phones are made of plastics, metals,ceramics and other trace substances. Land filled or incenerated cell phones create the potential for release of heavy metals or
halocarbons materials. Primitive recycling or disposal of cell phone waste to landfills and incinerators causes irreversible
environmental damage by polluting water and soil, and contaminating air. In this work, the treatment of cell phone wastes bythermal plasma under reducing condition has been investigated. The process developed is a drastic non-incineration thermalprocess, which uses extremely high temperature in an oxygen-starved environment to completely decompose input plastic wasteinto syngas, composed of very simple molecules viz : CO, H2 and hydrocarbons.During the process, the combustible reformedgas was recovered. The experimental results show that gaseous by-products are of CO, H2 and hydrocarbons (CxHy).
Generation of hydrogen gas of high concentration is from the hydrogen of the plastic part of the cell phone waste. Formation ofhydrocarbons is also from the carbon and hydrogen part of the cell phone waste. CO2 generation is almost below the detection
limit. No significant other toxic gases such as NOx and H2S were observed. SEM, XRD analysis of the plasma treated cell phone
residue has also been charaterized.Research results indicated that this thermal plasma technique is an energy recovery systemcontributing saving of resources or reduction of climate change gases.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------Keywords: E-waste, thermal plasma, combustible gas, metal recovery

1. Introduction
Cell phone waste, as one of E-waste, is much morehazardous than many other municipal wastes because it
contains thousands of components made of deadly
chemicals and metals. Cell phone, today an indispensable
service facilitating everyday life, has experienced atremendous increase in penetration since theimplementation of the innovative Global System for Mobile
Communication (GSM) standard in the early 1990’s.
Concern over the negative impacts associated with theproduction, use and end-of-life (EoL) of cell phone isparticularly high due to large production volumes andcharacteristically short time scale of technological andstylistic obsolescence. Cell phones contain a large numberof hazardous substances and valuable metals. Hazardous
substances can pollute the air when burned and leach into
soil and drinking water when buried in landfills. These toxic
substances include arsenic, lead, cadmium, copper, nickel,etc. and valuable metals includes gold, silver etc. The
disposal of cell phones thus needs to be managed in anenvironmentally sound way to minimize releases into theenvironment and threat to human health. When recycled
responsibly, the metals can be put back into circulation,
decreasing the need for new metal mining. The objective of

this work is to treat cell phone waste by thermal techniquefor its safe disposal and option for recovery of metals fromcell phone wastes.

2. Materials and Methods:
Cell phone waste was first separated into display and nondisplay part. After crushing, the samples were cut into
small pieces of around 5 mm size by sheet metal cutting
scissor. With a magnet, ferromagnetic were separated fromnon-ferromagnetic components. Cell phone waste wasdivided into four categories: Display magnetic(dm), display
non-magnetic (dnm), non-display magnetic (ndm), andnon-displaynon-magnetic (ndnm). Cell phone waste
samples were placed into a 99.8 % pure alumina reactor
with maximum operating temperature of 1950ºC in
reducing atmosphere. The ceramic reactor with a diameterof 7.5 cm and depth of 2.6 cm was placed 5 cm below thetorch. The sample weights were mostly in between 7 g and10 g. The thermal plasma was generated by a DC 10 kW
plasma torch and was ejected vertically through the top of
the environmental chamber. The power was limited to 1.5
kW. Pure argon gas with a fixed flow rate of 35 L/min was

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

used in order to produce a reducing atmosphere. A
constant-voltage power supply, in series with a resistor
bank, was applied to control the power of the plasma torch.
K-type thermocouple was introduced in the environmental
chamber to measure the temperature near the reactor wall.
An on-line combustion gas analyzer (Eurotron Greenline
8000) and a hydrogen gas analyzer (Beacon 200) wereinstalled at the exit of the reaction chamber behind a heatexchanger. All samples were treated for 30 minutes.

4. Conclusion··

3. Results and Discussions:·The results clearly shows that the exhaust gas contects
mainly H2 and hydrocarbons (CxHY) as conbustible gas
which has the heating value and can used for power
generation.

···

1400
1200

[H2] in ppm

1000
800

Plasma treatment of cell phone waste in reduced
condition generates gaseous components viz.
hydrogen (H2), carbon monoxide (CO) andhydrocarbons (CxHy), which are combustiblegas. So, this system is an energy recovery
system- contributing saving of resources or
reduction of climate change gases.
Provides volume reduction of the waste streams
contains only the metallic portions, which can berecycled to get the valuable and precious metals.
Complete destruction of plastic part of cell phonewaste may be possible provided reactor design
has to be modified.
Reduce the need for landfill
Safer disposal technique of cell phone waste.
Plasma chemistry is in the forefront of modern
environmentalanalyses.
Theuniquecharacteristics of plasmas should result in muchbroader applications in environmental mitigation
and are increasingly becoming valuable
environmental tools in future research ofenvironmental areas.

dm

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600ndmndnm[1]400200005101520253035Time (mins)

Concentration of H2 as a function of treatment timewith argon flow rate at 35 L/min

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300

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dmdnm

250
[CxHy] in ppm

ndmndnm200
150
100500051015202530Time (mins)

Concentration of CxHy as a function of treatment
time with argon flow rate at 35 L/min

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013