LIQUID CRYSTAL RECOVERY - Loughborough University · Outline Introduction – liquid crystals,...
20
LIQUID CRYSTAL RECOVERY Dr Avtar S Matharu SUMEEPnet, March 2008 Loughborough University
Transcript of LIQUID CRYSTAL RECOVERY - Loughborough University · Outline Introduction – liquid crystals,...
LIQUID CRYSTAL RECOVERY
Dr Avtar S MatharuSUMEEPnet, March 2008Loughborough University
Outline
Introduction – liquid crystals, LCDs, markets, WEEE
Recovery and isolation process
Results and Successes
Summary
Acknowledgements
Introduction: what are LCs?
REINITZER, 1888
O
O
GRAY, 1972
C N
FRIEDEL, 1922
LEHMANN, 1889
Introduction: Overview
Introduction: Molecular Structure
XA B
CH=N OCnH2n+1H2n+1Cn
Calamitic liquid crystals
Elongated rod- like molecules
FC5H11
FC3H7
H
H
F
F
OC2H5C5H11
C3H7
H
H
F
F F
F
CH3
Introduction: LCDs and WEEE
WEEE DIRECTIVE (2002/96/EC)
“LCD containing WEEE with a surface area greater than 100 cm2 and those with Hg containing backlights must be isolated…”
LCs classified as non-hazardous (waste code number 16 02 16)
BUT
Persistent and volumes are growing
Introduction: market shareSales revenue $100 billion
(2008)
100 million LCDTVs sold 2006/7
LCDTV largest growth area
48 million m2 LCD glass sold (2007)
LCD containing WEEE is fastest growing waste source in the EU
Diagonal size
/inch
Panel Weight
/g
Numbers produced /millions
Total weight LCD panels
/tons
European share(%)
LCD panel tonnage in
Europe
15 320 97.6 31.232 40 12.493
17 400 169.9 67.960 35 23.768
30 1, 110 78.2 86.802 40 34.721
Total 345.7 185.994 70.982
Introduction: volumes (2007)
Introduction: volumes (2007)
based on 48 million m2 of glass
LC Price $ per 15” display
$ LC Price Price*$/gram
$ LC value (millions)
$ LCD value (millions)based on 1% discarded
cm2 Inch2 m2
3 0.0043 0.027 43 8.5 2064 20.64
5 0.007 0.046 71.5 14.3 3432 34.32
7 0.01 0.065 100 20 4800 48.00
The amount of LC based on glass area sold = 240, 000 kg!!!
Introduction: volumes (2007)
Indium
By-product of zinc mining (1 – 100 ppm)
Price in 2002: $100/kg
Price in 2008: $750/kg
Amount sold worldwide 20 metric tons
How to remove Polarizers
How to open Panels
How to collect liquid crystals
Analysis and Re-use
How to dismantle Display
Recycling and Re-use of LC from LCDs
Project Aims
Plastic
Aluminium
TFT:Mo, Al, Si, In, Sn
CCFL
C/F:Resin, Cr, ITO
Glass plate+ Polariser
Glass Plate + Polariser
LIQUID CRYSTAL
Epoxy resin, cond. dots
Introduction: (Dis)assembly
COG, COF connections
IDPhysicalproperties
Shell Sound BoxPCB Module
Bezel, etc PanelBack Light PCB PolarizerCOF
Reflector DBEF FrameCCFL BEFLGP Diffuser
Seal Glass TFTL C Mixture
Others
C/F
LC 1
LC 2
LC n
……RE-USE
Power Supply
Isolate and Purify
Recovery and Isolation
Recovery and Isolation
R.S. Oakes, A.A. Clifford and C.M. Rayner. J. Chem. Soc., Perkin Trans. 1, 2001, 917-941
500 ml extractor capacityTwo 500 ml fractional separatorsExtraction parameters
0-50 g/min flow rate25-125 ºC0-400 Bar
Recovery and Isolation
THAR Supercritical CO2 Reactor
60 Bar, 60 °C
302 mg recovered
% Recovery (w/w) = 0.15
Atmospheric, 40 °C
110 mg recovered
% Recovery (w/w) = 0.05
Total % recovery (w/w) = 0.2
Extraction at 250 Bar, 40 ºC for 60 minutes
Results and Successes
Results and Successes
SummaryDis-assembly
Liquid crystal
Isolation
Both sCO2 and liquid CO2
AcknowledgementsUniversity of York:Dr Andrew Hunt; Dr Colin Ellis; Dr Simon Breeden; Dr Stephen Cowling; Professor John Goodby; Professor James Clark; Joseph Bottomley
Technology Strategy Board
Project REFLATEC-Tech Innovation; SIMS; NIS; ADR; (Botanix); Engelhaard; Glass Technology Services; Martin Goosey; Critical Processes; UKDL
RID – Alan Dukinfield; Argos
