Dr. Subodh K. Das

President & CEOSecat, Inc.

Designing Aluminum Alloys for a Recycling Friendly World

Presented To:Aluminum AssociationSheet and Plate Division

Spring Meeting Montreal, CanadaApril 24th, 2006

Outline of Presentation

• Recycling advantages and incentives– Recycled aluminum is the “new Urban Mine”– “Secondary“ is the new “Primary”

• Opportunities to maximize recycling• Aluminum alloy design for recycling

– Rationales– Opportunities– Recommendations

• Looking to the future

Number of Primary Smelting Plants in the U.S.

0

5

10

15

20

25

30

35

1980 1990 2000 2003 2010

2003: Fourteen (14)

Smelters Operating

SMELTERS OPERATING - 2003

• 8 Alcoa

• 2 Century

• 1 Alcan

• 1 Norandal

• 1 Ormet

• 1 Columbia Falls

SOURCE: LIGHT METAL AGE

??

U.S. Trends of Re-Melting vs. Smelting(000 Metric Tons)

02,0004,0006,0008,000

10,00012,00014,00016,00018,00020,000

1980 1990 2000 2010 (e) 2020 (e) 2030 (e)

RE-MELTING SMELTING

SOURCE: SECAT, INC.

Why Recycling?

The Aluminum Can Recycling Rate, 1992-2004

45

50

55

60

65

70

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

%

National Aluminum Beverage Can Recycling Rate Trends.

1% change in recycling rate has an economic impact of approximately $12 million

Trashed cans contribute about $600 million to the nation’s

trade deficit each year

Impact of Recycled Automotive Aluminum

• Two largest areas are cans and autos• Can recovery reached ~67% in early 1990’s – now at

~50%; cultural, societal and technical issues• Auto metal recovery >90%; aided by regulations,

shredders and lack of individual choice.• Recovery of Al from autos has exceeded all other scrap

sources since 2005• We have to learn to make as much new aluminum

products as technically possible from recycled automotive aluminum in the US

Advantages of Aluminum Recycling

• Recycling aluminum provides metal for 5% of energy invested in new primary aluminum and only 5% of CO2 produced

• Economic savings to municipalities supports creation of new or enlarged recycling facilities

• Domestic recycling reduces trade deficit and minimizes dependence on overseas metal sources

• The price of alloying elements such as Cu, Mn, Mg, etc are rising at equal or higher rate than Al

Characteristics of the “Recycling Friendly World”

• Ecology – Recycling and Consumption• Advanced Processing and Technology• Recycling Friendly Alloy Systems• High Value, Recycling Friendly Products• Good Public Awareness of Recycling

Challenges in Achieving the “Recycling Friendly World”

• Improve efficiency of metal recovery• Increase effectiveness of shredding and sorting

technology• Identify useful byproducts available through use of

secondary scrap• Broaden range of alloys readily produced from

recycled metal• Retain domestic aluminum scrap in US and lower

exports to China and India

Recycling Successes to Recognize

• Automotive Aluminum recovery and part pre-sorting

• Laser induced breakdown spectroscopy (LIBS) for finer sorting after shredding

• Alternative products such as “de-ox,” Fe-bearing aluminum for de-oxidizing steel

New Focus for Discussion – Optimizing Alloy Design for Recycling

• Focuses on “properties” rather than “chemistry”• Requires careful consideration of challenges from higher

impurity contents of recycled metal• Requires testing and qualification of new compositions for

important applications

• Revisits applicability and commercialization of the unialloy concept for packaging

Compositions of Recycled Aluminum (ref: Gesing, HVSC)

Lot Al Cu Fe Mg Mn Si Zn Other

W1 97.1 0.11 0.59 0.82 0.21 0.51 0.45 0.19

W3 93.1 0.95 1.01 0.89 0.12 2.41 1.25 0.27

C1 83.5 4.40 1.10 0.40 0.30 8.00 1.90 0.40

C3 88.4 2.50 0.75 0.58 0.26 5.18 1.27 1.09

WC 90.1 2.30 0.80 0.50 0.20 4.50 1.20 0.30

Difficulties Utilizing Recycled Al Scrap Directly

• Higher impurity levels– Fe buildup from equipment– Si levels from cast components– “Others” levels exceed AA limits

• Special handling called for– Segregate wrought and cast alloys when practical– Target alloys for reusing recycled metal

• To optimize use of recycled metal, new alloy options would be desirable

Design New Wrought Aluminum Alloys For Use of Recycled Metal

• Useful preliminary rationale– Select compositions from each series

representative of their strong points– Adjust limits on impurities to higher levels,

potentially acceptable for many applications

• Recognize implications of increased levels of impurities, and need to reset new limits based upon “performance” and not “chemistry”

Some Potential Candidates for Recycled Aluminum Alloys

Alloy Si Fe Cu Mn Mg Zn Other

2xxx 0.7 0.6 5.5-7.0 0.2-0.4 0.7 0.45 0.19

3xxx 0.7 0.6 0.89 1.0-1.5 0.8-1.5 1.25 0.27

5xxx 0.7 0.6 0.40 0.05-0.4 2.0-3.0 1.90 0.40

6xxx 0.3-1.0 0.6 0.58 0.30 0.4-1.0 1.27 1.09

7xxx 0.5 0.6 0.50 0.30 2.0-2.8 4.0-6.0 0.30

More In-Depth Evaluation of Recycling Friendly Alloys Needed

• Gain more specific information on the volume and compositions of aluminum alloy recycled from specific markets

• Fine-tune candidate compositions of recycle-friendly alloys based upon findings

• Critically evaluate wrought products made from proposed recycle-friendly alloys

Critical Evaluation of Recycling Friendly Alloys

• Determine, among others:– Toughness– Formability– Corrosion resistance

• Relate results to design requirements of intended applications, e.g.,– Building & highway structures– Industrial piping & tanks– Consumer durables

• Refine “compositions” as needed to obtain required “performance”

Conclusions

• Advantages of recycling aluminum justify maximization of potential

• Some successes to report in shredding, sorting, and alternative products

• Inadequate attention given to optimizing alloy design for a recycle-friendly environment

• Proposals put forth as to how such alloy design optimization might be approached

• Evaluation testing to match performance requirements proposed

The Next Steps?

• Establish recycling alloy optimization leadership team• Generate financial support• Phase 1 – Analyze volumetric recycling content by market• Phase 2 – Optimize new alloy compositions for use of

recycled metal• Phase 3 – Evaluate properties and “performance” of new

alloys, and adjust “chemistry” accordingly• Results will be published in Light Metals 2006 and presented

at the annual TMS meeting in San Antonio in 2006• Future research will be published in Light Metal Age (June

2006), International Aluminum Alloys Conference (July 2006) and Journal of Metals (August 2006)