LIQUID CRYSTAL RECOVERY - Loughborough University · Outline Introduction – liquid crystals, LCDs, markets, WEEE Recovery and isolation process Results and Successes Summary Acknowledgements

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: LCs everywhere

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