panias dimitrios associate professor in extractive metallurgy
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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. society and the consumption of metals. Global Iron and Steel Production. - PowerPoint PPT PresentationTRANSCRIPT
Panias DimitriosAssociate Professor in Extractive Metallurgy
National Technical University of Athens
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Global Iron and Steel
Production
Global Copper Production
Global Aluminum Production
Mill
ion
tonn
es
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Bearable Equitable
Sustainable
Via
ble
i nnovat I on
i n n o v a t i o ni n n o v a t i o n
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Red Mud 2kg
Bauxite 5.1kg
Al2O3 1.93kg
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Chemical Species
%wt (dry basis)
Fe2O3 47.74%
Al2O3 16.22%
CaO 10.73%
SiO2 6.09%
TiO2 5.93%
Na2O 2.51%
V2O5 0.21%
-SO3 0.60%
-CO2 1.63%
H2O(cry) 8.35%
Resource for Pig-Resource for Pig-Iron ProductionIron Production
Common Resources Common Resources for Mineral Wool for Mineral Wool
productionproduction
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Total Utilization of Total Utilization of Bauxite ResidueBauxite Residue
No Solid/Liquid No Solid/Liquid WastesWastes
Red Mud
Pig Iron
Mineral Wool
CO2 off-gases
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1MVA dust 1MVA dust treating AC treating AC
EAF with 1 ton EAF with 1 ton Batch CapacityBatch Capacity
Melt Spinning Melt Spinning Fiberizing LineFiberizing Line
25 tons of 25 tons of BR has BR has
been treatedbeen treated
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Pig Iron %w/wFe (%wt) 93.44C (%wt) 4.59S (%wt) 0.07P (%wt) 0.22Si (%wt) 1.12Cr (%wt) 0.50Total 99.94
Used in Used in Secondary Secondary
Steel Steel Industry as Industry as 21% w/w 21% w/w
substitution substitution of Steel of Steel scrapscrap
White Iron Grinding White Iron Grinding BallsBalls
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wool %w/wFe2O3 1.1SiO2 26.5CaO 23.4Al2O3 31.1Cr2O3 0.1MgO 8.3TiO2 6.1Na2O 1.8
Wool of excellent qualityWool of excellent qualityλ = λ = 0,034 W/m.K0,034 W/m.KMean Fiber Diameter 7 Mean Fiber Diameter 7 μμmmBright white color (low Mn content)Bright white color (low Mn content)High Mechanical resistance due to High Mechanical resistance due to high TiOhigh TiO22
Industrial pipes insulationIndustrial pipes insulation
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Extrapolation for a 5.0 MVA EAF Extrapolation for a 5.0 MVA EAF treating 1300 tons of bauxite treating 1300 tons of bauxite residues and producing 442 tons of residues and producing 442 tons of pig iron and 931 tons of mineral pig iron and 931 tons of mineral wool per monthwool per month
Pig Iron revenues (calculated at a Pig Iron revenues (calculated at a market price of 415market price of 415€/€/t) amount to t) amount to 25% of operational costs25% of operational costs
Mineral wool revenues depend on Mineral wool revenues depend on market price (depends on product market price (depends on product quality and market demand)quality and market demand)
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High Electrical Energy consumption (an High Electrical Energy consumption (an upgraded energy form with high cost and upgraded energy form with high cost and exergy content) for production of chemical exergy content) for production of chemical work and heatwork and heat
Molten Salts ElectrolysisMolten Salts Electrolysis
AlAl22OO33 = 2Al = 2Al3+3+ + 3O + 3O2-2-
Cathode: 4AlCathode: 4Al3+3+ + 12e + 12e-- = 4Al = 4Al
Anode: 6OAnode: 6O2-2- + 3C + 3Cgraphitegraphite = 3CO = 3CO2(g) 2(g) + 12e+ 12e--
Increased Environmental Impact due to Increased Environmental Impact due to mainly COmainly CO22 emissions emissions
Low volumetric efficiency due to 2 Low volumetric efficiency due to 2 Dimensional Electrolytic Reactor. That Dimensional Electrolytic Reactor. That means, for a given production capacity, a means, for a given production capacity, a big number of cells and therefore big big number of cells and therefore big industrial space are necessaryindustrial space are necessary
Typical Aluminum SmelterTypical Aluminum Smelter
-around 300 electrolytic cellsaround 300 electrolytic cells
-125.000 ton/y Al production125.000 ton/y Al production
New generation smeltersNew generation smelters
400-500 kton/y Al production400-500 kton/y Al production
Located in Middle East, China, Russia, Located in Middle East, China, Russia, India, Malaysia and AfricaIndia, Malaysia and Africa
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AlAl22OO33 + 3C = 2Al + 3CO + 3C = 2Al + 3CO(g)(g)
Substitution of a part of Electrical Energy Substitution of a part of Electrical Energy with the chemical and thermal energy of with the chemical and thermal energy of carboncarbon
Decrease of waste heatDecrease of waste heat
Higher volumetric efficiency due to 3 Higher volumetric efficiency due to 3 Dimensional ReactorDimensional Reactor
Potential for waste heat recoveryPotential for waste heat recovery
For a given production capacity For a given production capacity - smaller reactor size and thus industrial - smaller reactor size and thus industrial space space - less capital cost - less capital cost
Electrolytic Process
7.42kg CO2
1kg Al
1.93kg Al2O3
15.3MJ Canode
56.24MJ Electricity
44.73MJ Electricity20% decrease
Carbothermic Process
24.23MJ CReductant
Cathode: 4AlCathode: 4Al3+3+ + 12e + 12e-- = 4Al = 4Al
Anode: 6OAnode: 6O2-2- + 3C + 3Cgraphitegraphite = 3CO = 3CO2(g) 2(g) + 12e+ 12e--
1.66kg CO
2.6kg CO2
Recovery of
15.82MJ
Reduction in indirect
CO2 emissions
Decrease of CODecrease of CO22 emissions emissions
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2Al2Al22OO33 + SiO + SiO22 + 8C = 4AlSi + 8C = 4AlSi0.25(l)0.25(l) + 8CO + 8CO(g)(g)
1. Co-Reduction of Alumina and Silica1. Co-Reduction of Alumina and Silica
Under high temperatures (>2500Under high temperatures (>2500ooC)C)
Under vacuum (1500Under vacuum (1500ooC)C)
AlAl22OO33 + 3C = 2Al + 3C = 2Al(g)(g) + 3CO + 3CO(g)(g)
AlAl22OO33 + 3C = 2Al + 3C = 2Al(g)(g) + 3CO + 3CO(g)(g)
2. Gaseous aluminum production2. Gaseous aluminum production
all are proven in Laboratory Scale all are proven in Laboratory Scale
is now tested in Pilot Scaleis now tested in Pilot Scale
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2Al2Al22OO33 + SiO + SiO22 + 8C = 4AlSi + 8C = 4AlSi0.25(l)0.25(l) + 8CO + 8CO(g)(g)
Carbon Carbon Source: Source: Wood Wood charcoalcharcoal
Binder: 7% Binder: 7% corn starchcorn starch
26002600ooCC<1000<1000ooCCMolded Al-Si AlloyMolded Al-Si Alloy
Identification Number
Alwt.-%
Siwt.-%
Ex. 1: Si/Al=0.26 (T=1300°C)
72.53 25.58
Ex. 1: Si/Al 0.26 (T=700°C)
71.37 25.95
33% of 42 Mt 33% of 42 Mt of Global Al-of Global Al-Castings are Castings are AlSi Castings AlSi Castings
Al 77.07 wt.-%
Si 22.93 wt.-%
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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
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Concept:
•Reactor under vacuum
•Concentrated Solar Radiation provides process heat
•Condenser before vacuum pumps collects the metal.
Energy of the process = pumping work (electricity) + concentrated solar radiation.
Quartz Window
ZIrconia
Before test After test
Condensed Deposit
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Estimated gains of the new Alumina Smelter in Comparison to the Hall-Heroult
Energy Source Energy Savings Reduction in GHG Emissions
Exergy Efficiency Increase
Coal based electricity 16% 35% 3%
Hydroelectricity 10% 65% 5%
Hydroelectricity for H-H andConcentrated Solar for New Smelter
68% 65% 82%
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