Abstract No. 42. V. Sturm, R. Fleige, M. de Kanter, R. Noll, C. Fricke- Begemann 1 R. Leitner, K. Pilz, D. Fischer, G. Hubmer 2

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1 Title: Authors: Company/ Institute: Presentation Abstract: Abstract No. 42 Inline analysis of liquid slag V. Sturm, R. Fleige, M. de Kanter, R. Noll, C. Fricke- Begemann 1 R. Leitner, K. Pilz, D. Fischer, G. Hubmer 2 1 Fraunhofer Institute for Laser Technology ILT, Aachen (DE), 2 voestalpine Stahl GmbH, voestalpine Straße 3, 4020 Linz (AT) Oral presentation Slag from crude steel production at the voestalpine steel works is inspected before tapping to evaluate its composition and usability as raw material, e.g., for construction works. Laser-induced breakdown spectroscopy (LIBS) is applied for the inline analysis of the liquid slag. The transporters with ladles are stopped at a measurement location, where the slag is measured by LIBS at a distance of several meters. The slag surface with temperatures from 600 to 1400 C consists of liquid slag and solidified slag parts. Automatic measurements at varying filling levels of the ladle are realized. The measurement duration amounts to 2 min including data transmission to the host computer. Analytical results of the major components such as CaO, Fe, SiO2, MgO, Mn, and Al2O3 are compared with reference values from the steel works laboratory for solid pressed slag samples as well as for samples from the liquid slag. Stable 24/7 operation is achieved and more than five thousand ladles have already been inspected automatically demonstrating the capability of LIBS for inline analytical tasks in rough industrial environments. Contact Address: Fraunhofer ILT, Steinbachstr. 15, Aachen, Germany + 49 (0) volker.sturm@ilt.fraunhofer.de

2 INLINE ANALYSIS OF LIQUID SLAG V. Sturm, R. Fleige, M. de Kanter, R. Noll, C. Fricke-Begemann, Fraunhofer Institute for Laser Technology ILT, Aachen, Germany R. Leitner, K. Pilz, D. Fischer, G. Hubmer, voestalpine Stahl, Linz, Austria 9th International Conference Düsseldorf May 19-21, 2015 Inline analysis of liquid slag Automatic 24/7 operation at a steel works Introduction Analysis method Results Conclusions Seite 2CETAS Liquid slag is poured out to slag pits for cooling and further processing Source: K. Pilz, Berg- und Hüttenmännische Monatshefte (BHM) 2012, 157, (in German) 2015

3 Introduction Slag composition is of interest for further use such as bituminous road construction, cement industries and others Slag amount at voestalpine Stahl, Linz: approx. 600 x 10 3 tons per year LD slag is carried in ladles by transporters from tapping to slag pits Composition variies from ladle to ladle Goal: > Analysis and classification of each slag ladle in order to direct the transporter to defined slag pits, > Automatic 24/7 routine operation at the steel works, > Measuring time less than 2 min Analysis method: Laser-Induced Breakdown Spectroscopy - LIBS Seite 3 After steel tapping, tons of liquid slag are filled into ladles Seite 4 (2) (1) Direct transport to same slag pits Inline analysis of each ladle during a short stop (2) Source: V. Sturm et al, Analytical Chemistry 2014, 86, American Chemical Society Liquid LD slag at the steel works of voestalpine, Linz Slag poured into defined slag pits according to analysis and classification

4 Analyzing installation at voestalpine Stahl, Linz Slag transporter with ladle during analysis underneath measuring cabin Seite 5 LIBS analyzer Optical module with laser head, optics, laser distance meter and pyrometer, fibre optic cable to spectrometer Measuring distance 3.7 m N2 purged measuring probe with controlled distance (0.15 m) to the slag surface Automatic adaption to varying filling heights (> 1m) Seite 6 View inside the measuring cabin with LIBS analyzer

5 Camera view into the slag ladle during the LIBS analysis Slag exhibits at the surface a partly solidified and cragged crust, the free surface of the liquid slag, or a spatial mixture of solidified parts and melt The measuring probe and the laser-induced plasma plume are moving across the slag surface Seite 7 Results for solid slag samples, #1: Basicity CaO/SiO2, Measuring distance 3.7 m Good correlation of 94 samples No outliers Seite 8

6 Results for solid slag samples, #2: Fe/CaO Measuring distance 3.7 m Good correlation of 94 samples No outliers Seite 9 Results for solid slag samples, #3: Mass fractions Measuring distance 3.7 m Good correlation of 94 samples No outliers Seite 10

7 Results for liquid slags, #1: Basicity CaO/SiO2, Reference analysis by steel works laboratory Difficult sampling: Cooled samples taken from slag pits Variation of composition less due to production conditions Seite 11 Results for liquid slags, #2: Fe/CaO Reference analysis by steel works laboratory Difficult sampling: Cooled samples taken from slag pits Variation of composition less due to production conditions Seite 12

8 Results for liquid slag, #3: Mass fractions Reference analysis by steel works laboratory Difficult sampling: Cooled samples taken from slag pits Variation of composition less due to production conditions Seite 13 Comparison to other published results m.-% (a) solid slag [1], 0.20m, 20 C (b) solidif. glass [2], 0.25 m, 20 C (c) solid slag this study, 3.7 m, 20 C (d) liquid slag this study, 3.7 m, C range RMSEP range RMSE range RMSEP range RMSEP P CaO SiO Fe MgO Mn Al 2 O Mean (a) Laboratory, OWD 0.2 m, 20 C, sample stand, Ar; (b) Laboratory, OWD 0.25 m, 20 C, air; (c) this study, OWD 3.7 m, 20 C, measuring probe, N2; (d) this study, slag ladles at plant, OWD 3.7 m, C, measuring probe, N2. [1] Kraushaar, M.; Noll, R.; Schmitz, H.-U. Appl. Spectrosc. 2003, 57, [2] Laville, S.; Sabsabi, M.; Doucet, F.R. Spectrochim. Acta, B: At. Spectrosc. 2007, 62, Solid slag results comparable despite much larger distance Liquid slag results are, at maximum a factor of two greater Source: V. Sturm et al, Analytical Chemistry 2014, 86,

9 Monitoring analyzer stability Repeated measurements of the basicity of two monitor samples showing the stability of the LIBS measurement Software configured automatic measurements of monitor samples Seite 15 Three-months test run during routine production, #1 Basicity of liquid slag Each circle marks a slag ladle, and the (blue) solid line is the moving average of 30 slag ladle measurements. Seite 16

10 Three-months test run during routine production, #2 Fe oxide content of liquid slag Each circle marks a slag ladle, and the (blue) solid line is the moving average of 30 slag ladle measurements. Seite 17 Conclusions For the first time at a steel works, liquid slag is analyzed inline by an automated LIBS system within 2 min in the ladle of a slag transporter. Data transfer to the host computer is included as well as an automatic adaption to varying filling heights of the ladles Stable 24/7 operation during the first three-month test run has been demonstrated successfully under these harsh environmental conditions. 18CETAS The presented application shows the versatile potential of LIBS for inline process analysis in industry. Seite

11 Seite 19 Thank you for your interest.