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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