Quality of open air, single-shot laser-induced breakdown spectroscopy (LIBS) spectra from waste particles

(1)

Quality of open air, single-shot

laser-induced breakdown spectroscopy (LIBS)

spectra from waste particles

Han Xia, TU Delft

18-19 March 2015, OCM2015, Karlsruhe, Germany

Supervisor: Dr. M.C.M Bakker

Resources & Recycling group, Delft University of Technology

(2)

Cement & aggregate from EOL concrete:

online LIBS for quality inspection

Outline

1. C2CA in brief: a new process for concrete recycling

• Existing vs. proposed novel closed cycle for concrete wastes

• Online sensor for quality inspection needed

2. Online LIBS for quality control of recycled products

• LIBS qualitative & quantitative analyses

• Particle segregation in belt transport, air and moisture influences

(3)

Strukton - Theo Pouw - Heidelberg Cement - Holcim - DV - Laser 2000 – Inashco R&D

TU Delft - Roma - AGH University - ICE-HT - Barcelona - Leiden - TU Denmark

(4)

BAU and new approach for concrete waste

Reduced to 40 % in 2025

EU: 180 Mton/y

480 kg/capita

(5)

(6)

2): Process control for both

input and output products

1): Detection of components

in the earliest phase

3): Accurate

determination of

decisive elements

Dismantling

& Demolition

Autogenous

milling

ADR

Ca-rich

fraction

Si-rich

fraction

(7)

Online LIBS for concrete waste quality inspection

Major stages in the LIBS process. Source: “LIBS: fundamentals and applications” by Miziolek, A.W. on p.10 Lifespan of LIP after

firing a laser pulse LIBS experimental setup

(8)

Rebar

CEM

Aggregate

Ca

Si

Fe

Classification of concrete drill cores:

smart dismantling

(9)

PCA Classification of concrete waste components

LIBS spectra of various

concrete waste materials

(10)

-0.1 -0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 -0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 PC1 (70.2%) P C 2 ( 1 6 .3 % ) CEM Raw meal Limestone Marl Clinker Cal. sand Bauxite ADR fine

(11)

(12)

(13)

(14)

• Feeding duration for same

batch mass (circles).

• Material layer thickness on

the conveyor belt (triangles).

(15)

Segregation in the transport of concrete waste

L en g th ( m m ) H ei g h t (m m ) 50 100 150 200 250 10 20 30 40 50 60 70 0 5 10 15 20 25 30

(16)

Particle segregation in transport of concrete waste

Particles sink rate in the feed funnel (at its vertex)

vs. grain size for different moisture contents

(17)

(18)

Air & moisture influences

implication for wavelength selection

spectral abundance using (from left to right)

35 mm, 50 mm and 100 mm lenses

for each subgroup

spectral abundance using 100 mm lens

dry (left) vs. moisture (right)

(19)

Material dependent LIBS observation depth (OD)

air

wavelength [nm]

OD [mm]

35 mm

50 mm

100 mm

plastic

386, 387, 388 (CN),516 (C2)

2.8

3.5

5.3 Nitrogen

463, 500, 504, 568 (N II)

3.5

3.8

7.8 Water

656 (H

α

)

3.5

4.0

6.5 Oxygen

777 (O I)

2.0

2.5 -

glass

279 (Mg II), 393 & 397 (Ca I), 589 (Na I)

3.0

3.8

7.8 Nitrogen

463, 500, 504, 568 (N II)

3.3

4.5

6.0 Water

656 (H

α

)

3.0

4.0 -

Oxygen

777 (O I)

3.0

3.5

0.5 gravel

279 (Mg II), 288 &385 & 390 (Si I), 634 (Si II), 393 & 397 &

422 & 445 & 616 & 644 & 646 (Ca I), 309 (Al I), 455 & 493

(Ba II)

4.3

4.5

12.0 Nitrogen

463, 500, 504, 568 (N II)

4.3

5.5

13.0 Water

656 (H

α

)

4.0

5.5

(20)

plastic

glass

gravel

LIA [°]

CN

388 Ca

397 Na

589 Mg

279 Ca

318 Na

589 Al

309 Si

288

0

7.5

10.0

9.0

10

16.5

15.0

7.0

15

7.0

6.0

10.0

9.0

10

18.0

17.5

9.5

30

7.0

8.0

7.0

8.0

17.5

15.5

5.0

45

6.5

10.0

6.5

8.0

16.5

15.5

4.0

60

6.0

6.5

7.5

6.0

7.0

15.0

13.5

3.0

(21)

Summary

1. Proof of concept: online LIBS for quality control of recycled

products

• Compact, flexible, potentially low costs

• Classification & quantitative analysis

• Above the conveyor belt (35 cm/s) single-shot (100 Hz, 3.5 mm

between 2 shots), sampling directly on the stream

2. Online application aspects for concrete waste streams

• Transport segregation, air, moisture influences

(22)