HIGH VALUE RECYCLING OF REFRACTORIES THROUGH AUTOMATED SORTING

Transcription

1 HIGH VALUE RECYCLING OF REFRACTORIES THROUGH AUTOMATED SORTING Euroslag October 2015 Linz, Austria L. Horckmans, VITO, Belgium S. Connemann, ILT, Germany P. Dierckx, VITO, Belgium H. Knapp, RWTH Aachen, Germany P. Nielsen, VITO, Belgium J. Makowe, LSA, Germany F. Bouillot, RECMIX, Belgium A. Stark, Tritec, Hungary C. Fricke-Begemann, ILT, Germany A. Ducastel, Magnesita Refractories, Germany This project has received funding from the European Union s Seventh Programme for research, technological development and demonstration under grant agreement No

2 THE NEED FOR HIGH GRADE REFRACTORY RECYCLING Raw materials are critical for European refractory industry Production capacities of some important refractory industrial minerals Source: PRE, 2009 Raw materials play important role in product quality and cost (40-50% of refractory cost) Dominance of China as raw material source leads to supply risk and price increase

3 THE NEED FOR HIGH GRADE REFRACTORY RECYCLING EC Raw Materials Initiative, critical raw materials for the EU, 2014

4 THE NEED FOR HIGH GRADE REFRACTORY RECYCLING Stringent quality criteria require high purity sorting 4

5 THE REFRASORT PROJECT Aim: To develop an automated sorting technology for spent refractory bricks using non-destructive technology that delivers high purity fractions suitable for reuse as refractory raw materials Funded by European Union s Seventh Programme for research, technological development and demonstration under Grant Agreement Duration: November 2013 October 2016 Partners: 5

6 THE REFRASORT SYSTEM Sensor based sorting system Inlining & Singularization Pretreatment Identification Sorting 6

7 THE REFRASORT SYSTEM Mechanical system for inlining, singularization and sorting Inlining & Singularization Pretreatment Identification Sorting Garbage, metal Small bricks mm, kg Slag Broken and unshaped mm, kg Big bricks > 150 mm, 4-21 kg 7

8 THE REFRASORT SYSTEM Mechanical system for inlining, singularization and sorting Challenges Large size/weight variation have negative effect on throughput (ton/h) -> screening Heavy, large bricks (largest diameter > 300 mm, weight up to > 20 kg) Ejection system for at least 8 fractions Inlining & Singularization Pretreatment Identification Sorting Can we show this? Picture without nrs? 8

9 THE REFRASORT SYSTEM Mechanical system for inlining, singularization and sorting Inlining & Singularization Pretreatment Identification Sorting Dust removal Before Before After 9

10 THE REFRASORT SYSTEM Mechanical system for inlining, singularization and sorting Inlining & Singularization Pretreatment Identification Sorting Removal of metal-impacted bricks Economic value of the metal Reduce contamination in sorted fractions 10

11 THE REFRASORT SYSTEM Mechanical system for inlining, singularization and sorting Inlining & Singularization Pretreatment Identification Sorting Focus on 8 types that represent > 90% of shaped refractory production Tempered vs fired CaO % MgO % SiO2 % Al2O3 % TiO2 % C% MgO-C without antioxidant MgO-based MgO-C with antioxidant Fired MgO Doloma based Fired Doloma Carbon bonded Doloma Fired Bauxite Alumina based Fired Andalousite Fired Chamotte Recalculated to 100% mineral composition 11

12 THE REFRASORT SYSTEM Mechanical system for inlining, singularization and sorting Inlining & Singularization Pretreatment Identification Sorting Challenges: Dust/slag/carbonation layer at surface of ~100 µm 1 cm thickness hinders surface sensors Industrial operation requires fast analyses (< 1 s/brick) 12

13 SELECTION OF SUITABLE IDENTIFICATION SENSOR LIBS Laser induced breakdown spectroscopy 300 µm 2 step process: Cleaning (laser ablation): high energy densities (GW/cm²) lead to temperatures > C and vaporisation of material Measurement by identification of characteristic emission spectra Individual measurements few ms 13

14 LIBS: PRELIMINARY RESULTS Discrimination of main classes feasible based on Ca, Mg, Si content MgO Doloma Al-Si Further separation into 8 classes by introducing Al, C (ongoing) Source: ILT

15 LIBS SORTING RESULTS OF FIRST TRIALS Trial: 30 bricks spent refractories sorted into 3 main classes (MgO doloma alumina) at lab scale Result: 29/30 bricks sorted correctly - 1 doloma brick wrongly identified as magnesia leading to high CaO (> 4%) in MgO causing expansion cracks upon hydration Conclusion: Selectivity threshold for magnesia must be increased 15

16 COMPLEMENTARY IDENTIFICATION TECHNIQUES C identification complicated by surface decarbonisation Decarbonisation layer deeper than laser ablation -> less reliable LIBS identification of C at surface Alternative C identification sensors explored conductivity gives promising results (ongoing research) C-rich

17 CONCLUSION AND OUTLOOK» Mechanical sorting:» Laboratory prototype validated» Industrial demonstrator currently being installed» Identification:» LIBS» Settings for sorting for three main classes have been determined (Mg, Ca, Si)» Finetuning of thresholds needed in function of recycling specifications» Additional parameters (Al, C) for identification of 8 classes to be determined» Complementary C identification techniques under investigation» Functional demonstrator to be operational at industrial site of RECMIX by October