Innovative Separation Technology for Refractory Waste

A. Ducastel Magnesita Refractories, Germany H. Knapp RWTH Aachen University, Germany

E. Guéguen Magnesita Refractories, Germany F. Bouillot RECMIX, Belgium

L. Horckmans VITO, Belgium J. Makowe LSA, Germany

C. Fricke-Begemann Fraunhofer ILT, Germany A. Stark Tritec Metal, Hungary

UNITECR 2015 Vienna, September 18th

Important Refractory Raw Materials

Importance of recycling materials

REFRASORT project

Results of firsts sorting

Source: PRE

China is currently the main supplier of high volume of important Refractory grade raw materials

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Raw materials price evolution 2007 - November 2014

Source: PRE

Significant price

increase for:

• Bauxite

• BFA

• Graphite

• Sintered Magnesia

• Fused Magnesia

Refractory suppliers are under significant pressure:

Raw materials play a fundamental role on product quality Raw materials represents 40-50% of the cost of refractories Besides, Raw material cost, energy cost and environmental regulation

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Critical Raw Materials for EU

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54 raw materials reviewed from which 20 are considered as being critical

EU commission Statement:

“It’s worth recalling that all Raw Materials, even when not critical, are important for the

European Economy, and therefore not being critical doesn’t imply that a given Raw Material

and its availability to the European economy should be neglected”

How to improve in the customers the value in use of products? Invest and increase the use of own raw materials and strictly control of the costs Develop use of externally sourced recycled refractory materials Development of supply chain for obtaining used refractory materials that can be successfully processed and used for refractory brick production

REFRASORT Project

« Innovative Technologies for High Grade Recycling Refractory waste using non

destructive technology »

Objective

To develop an automated sorting and separation technology for used Refractory material which provides pure high quality

secondary raw materials adapted to the needs of Refractory production

REFRASORT Project

European Commission

7th Framework Program for Research, Technological development and Demonstration

Funding of new Research projects for shaping a more resource efficient economy in Europe

Importance of recycling materials

REFRASORT project

Results of firsts sorting

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Mechanical handling & LIBS technology

1. Lining up:

vibratory feeder

2. Isolation:

plate conveyer having high

velocity

3. Spacing:

pneumatically driven pushers;

parking position; adjustable timing

of releasing

Identification

4. Separation:

pneumatically driven pushers

Key technology to enable automated separation

= identification of individual pieces of refractories

Direct Laser analysis promises to fulfill the sensor requirements for industrial

operation in a separation plant

3D

shape and position by using laser-triangulation

LIBS measurements

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LIBS technology

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3D shape and position of one used

refractory brick by using laser-triangulation:

- points of the yellow grid mark the

measurement points where the 3D object

recognition analyzed the surface with

respect to the suitability for the subsequent

LIBS measurement

- red dots mark the most suitable surface

point(s) for the LIBS analysis

- object’s edges are shown in green

Laser-induced Plasma on a Piece of used

Refractory Pre-defined locations chosen by adjusting the laser beam direction Focused pulsed laser’s beam: - power densities in the range of GW/cm² are reached locally for short time - these are sufficient to vaporize every material, to dissolve the chemical bonds and heat the material to temperatures above 10 000 °C

LIBS technology

1) Craters produced by tailored

laser pulses in the cover layer of

a used brick

2) Microscopic photograph of one

crater (width ~300μm, depth

~100μm)

Laser-penetration of surface contamination:

Possibility to analyze deeper regions of the material by repeating the laser penetration on one spot

One measurement last few milliseconds:

this enables the analysis of fast-moving objects

1 2

300μm

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LIBS sorting

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A

MgO B

Doloma

C

Al-Si

Ability of LIBS to distinguish main types of Refractories, based on fresh samples

By setting all the major thresholds between elements like Ca, Mg, Si, Al, C, Cr, and Fe in

the LIBS system, it should be possible to manage to distinguish accurately the 8 different

families of refractories

Laser-induced plasma on fresh

refractory

A1: Mag-C with antioxidant

A2: Mag-C without antioxidant

A3: Fired MgO brick

B1: Fired Doloma brick

B2: Carbon bonded Doloma brick

C1: Fired Bauxite based brick

C2: Fired Andalousite based brick

C3: Fired Chamotte brick

Importance of recycling materials

REFRASORT project

Results of firsts sorting

LIBS sorting

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Chemical Analysis

(wt%)

Mag-C

recycling

Doloma

recycling

Alumina

recycling

CaO 5,42 58,22 0,43

MgO 92,88 39,12 0,73

SiO2 0,38 0,92 57,36

Fe2O3 0,42 1,01 1,98

Al2O3 0,67 0,48 36,29

C 2,25 4,41 -

TiO2 - - 1,31

K2O - - 1,46

Na2O - - 0,32

The threshold from which a sample is classified as magnesia, here the signal

intensity ratio MgO/CaO, should be pushed upward

30 used bricks, coming from three different refractory families (magnesia, doloma and

alumina), for each of them 12 measurements were done on the upper face of the used

brick : only one brick sorted as magnesia instead of doloma

XRF analyses done on the resulting sorted batches

Used bricks tested

Cylinders made from the sorted Mag-C recycling

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Recycling content (%) 0 30 50 80

Chem

ical A

naly

sis

(wt%

)

SiO2 0.51 0.49 0.45 0.42

Al2O3 0.24 0.47 0.52 0.77

Fe2O3 0.42 0.43 0.46 0.46

CaO 0.92 2.10 4.04 4.52

MgO 97.79 96.39 94.4 93.7

Aft

er

tem

peri

ng

Volume change % 0.09 0.33 0.67 0.87

BD (g/cm3) 2.97 2.95 2.91 2.88

AP (%) 4.6 6.4 9.0 10.3

CCS (N/mm2) 64 74 65 80

LOI (%) 9.9 8.0 6.1 5.2

Aft

er

Cokin

g a

t

1000

oC

BD (g/cm3) 2.92 2.91 2.89 2.84

AP (%) 10.8 12.0 14.4 16.0

CCS (N/mm2) 29 38 40 41

LOI (%) 1.3 1.4 1.6 1.4

Carbon content (%) 8.6 6.7 5.0 3.9

Important amount of doloma higlighted by chemistry analyses (CaO>4%)

Aspect of cylinders kept at room temperature for

two month (recycling content, respectively from

left to right: 0, 30, 50, 80)

Cracks when hydrated

More important volume change after tempering (at 300 °C for 2h)

Sorted doloma recycling used in monolithic formulation

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20, 30, 50, 60% of sorted doloma

recycling has been used to substitute the

virgin doloma

Same GSD than the reference

Proportional decrease in bulk density

Significant decrease in rammed density

But this recycling containing product

could still be used as a backfill or as

gap filler material

Conclusion

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The introduction of the laser based analysing and integrated sorting system REFRASORT will allow precise discrimination of the main refractory material classes and sub-classes from a stream of undefined recycled used refractories products

Further work is ongoing to identify the eight different families of refractories thanks to the LIBS system

Regarding the mechanical handling, the next step for the demo equipment is to prove reliability under industrial conditions

This novel technology will enable the refractory industry to re-use a larger quantity of used products than it is the case today and to counterbalance the commercial impacts of highly volatile raw material prices

THANK YOU FOR YOUR ATTENTION

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