Post on 19-Mar-2018
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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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