Panias Dimitrios Associate Professor in Extractive Metallurgy

1. Some steps forwards in sustainable exploitation of raw materials: The case of alumina and aluminum industry Panias Dimitrios Associate Professor in Extractive Metallurgy National Technical University of Athens

2. society and the consumption of metals Global Iron and Steel Production Global Copper Production Global Aluminum Production Million tonnes

3. Human wealth & the value of metals

4. Human welfare vs ecological footprint

5. Concept of sustainability i nnovat I on Equitable Bearable Sustainable Viable i n n o v a t i o n i n n o v a t i o n

6. How can innovations emerge? Primary Alumina and Aluminum Production Mass & Energy balances Enexal project

7. innovations IN bayer process Mass & Energy balances EXERGY ANALYSIS Bauxite 5.1kg Red Mud 2kg Al2O3 1.93kg Red mud is a valuable by-product and not a waste Enexal project

8. emerging innovation I : Red mud as a feedstock Resource for Pig-Iron Production Common Resources for Mineral Wool production Enexal project

9. emerging innovation I : Red mud as a feedstock Technology development CO2 off-gases Red Mud • Total Utilization of Bauxite Residue • No Solid/Liquid Wastes Pig Iron Mineral Wool Enexal project

10. emerging innovation I : Red mud as a feedstock Pilot scale testing 1MVA dust treating AC EAF with 1 ton Batch Capacity 25 tons of BR has been treated Melt Spinning Fiberizing Line Enexal project

11. emerging innovation I : Red mud as a feedstock Products Evaluation – PIG IRON White Iron Grinding Balls Used in Secondary Steel Industry as 21% w/w substitution of Steel scrap Enexal project

12. emerging innovation I : Red mud as a feedstock Products Evaluation – Mineral wool • Wool of excellent quality • λ = 0,034 W/m.K • Mean Fiber Diameter 7 μm • Bright white color (low Mn content) • High Mechanical resistance due to high TiO2 Industrial pipes insulation Enexal project

13. emerging innovation I : Red mud as a feedstock Process ECONOMIC Evaluation • Extrapolation for a 5.0 MVA EAF treating 1300 tons of bauxite residues and producing 442 tons of pig iron and 931 tons of mineral wool per month • Pig Iron revenues (calculated at a market price of 415€/t) amount to 25% of operational costs • Mineral wool revenues depend on market price (depends on product quality and market demand) Enexal project

14. The new bayer Plant Is more resource efficient and sustainable process Enexal project

15. innovations IN Aluminum Production Drawbacks of molten salts electrolysis • High Electrical Energy consumption (an upgraded energy form with high cost and exergy content) for production of chemical work and heat • Increased Environmental Impact due to mainly CO2 emissions • Typical Aluminum Smelter • around 300 electrolytic cells • 125.000 ton/y Al production • New generation smelters • 400-500 kton/y Al production • Located in Middle East, China, Russia, India, Malaysia and Africa Molten Salts Electrolysis Al2O3 = 2Al3+ + 3O2- Cathode: 4Al3+ + 12e- = 4Al Anode: 6O2- + 3Cgraphite = 3CO2(g) + 12e- • Low volumetric efficiency due to 2 Dimensional Electrolytic Reactor. That means, for a given production capacity, a big number of cells and therefore big industrial space are necessary Enexal project

16. emerging innovation II : CarboThermic Al Production The concept of carbothermic process Advantages of carbothermic process Cathode: 4Al3+ + 12e- = 4Al Anode: 6O2- + 3Cgraphite = 3CO2(g) + 12e- • Substitution of a part of Electrical Energy with the chemical and thermal energy of carbon Recovery of 15.82MJ 1.93kg Al2O3 2.6kg CO2 • Decrease of waste heat 1.66kg CO 7.42kg CO2 44.73MJ Electricity 20% decrease • Potential for waste heat recovery 56.24MJ Electricity Carbothermic Process Electrolytic Process 1kg Al • Decrease of CO2 emissions Reduction in indirect CO2 emissions • Higher volumetric efficiency due to 3 Dimensional Reactor 24.23MJ CReductant 15.3MJ Canode • For a given production capacity - smaller reactor size and thus industrial space - less capital cost Al2O3 + 3C = 2Al + 3CO(g) Enexal project

17. emerging innovation II : CarboThermic Al Production Modes of performing the carbothermic Al production 1. Co-Reduction of Alumina and Silica is now tested in Pilot Scale 2Al2O3 + SiO2 + 8C = 4AlSi0.25(l)+ 8CO(g) 2. Gaseous aluminumproduction • Under high temperatures (>2500oC) • Under vacuum (1500oC) all are proven in Laboratory Scale Al2O3 + 3C = 2Al(g)+ 3CO(g) Al2O3 + 3C = 2Al(g)+ 3CO(g) Enexal project

18. emerging innovation IIa : High temperature CarboThermic Al-si alloy Production Electric Arc FUrnace 2Al2O3 + SiO2 + 8C = 4AlSi0.25(l)+ 8CO(g) Carbon Source: Wood charcoal Binder: 7% corn starch • 33% of 42 Mt of Global Al-Castings are AlSi Castings Al 77.07 wt.-% Si 22.93 wt.-% Molded Al-Si Alloy <1000oC 2600oC Enexal project

19. emerging innovation IIB : High temperature CarboThermic Gaseous Al Production Concept: • Hollow electrode EAF • Feeding Alumina-Carbon pellets directly in the arc zone • Controlled feeding rate • No liquid phase formation • Water cooled lid acts as condenser • Argon Overpressure No Liquid Phase Homogeneous Condensed Material with Metallic Shine Almost Pure Aluminum Challenges Proper very fast Aluminum condenser Plasma furnace instead of eaf Enexal project

20. emerging innovation IIc : Vacuum CarboThermic Gaseous Al Production Concept: • Reactor under vacuum • Concentrated Solar Radiation provides process heat • Condenser before vacuum pumps collects the metal. Quartz Window ZIrconia Condensed Deposit Energy of the process = pumping work (electricity) + concentrated solar radiation. Challenges Proper very fast Aluminum condenser Development of a hybrid solar-electrical reactor After test Before test Enexal project

21. The new alumina SMELTER A sustainable perspective for the european aluminum industry aluminum mills versus hall-heroultmegaplants Enexal project

22. Can the new alumina & aluminum plant become a reality? Synergy and Symbiosis among different industrial sectors & society Support of radical ideas by the research funds Thrust from the Research Community Drivers towards this direction Change in mentality of European Citizens

23. Thank you for your attention