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Industry Quality Review

Magnesium Anodes. Industry Quality Review. September 2008 NACE Central Area Conference. Magnesium Anode Electrochemical Properties. -1.75V Open Circuit Voltage High Potential -1.55V Open Circuit Voltage Standard Alloy 1000 Amp-hrs/pound - Theoretical

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Industry Quality Review

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  1. Magnesium Anodes Industry Quality Review September 2008 NACE Central Area Conference

  2. Magnesium Anode Electrochemical Properties • -1.75V Open Circuit Voltage High Potential • -1.55V Open Circuit Voltage Standard Alloy • 1000 Amp-hrs/pound - Theoretical • 500 Amp-hrs/pound - Nominal • 50% current efficiency - Nominal

  3. Quality & Performance Factors • Alloy Chemistry • Potential (voltage) • Current efficiency

  4. Alloy Chemistry • ASTM B843 defines alloy requirements • >98.5% magnesium • Typically, 100% testing of every heat • Chemistry alone does not identify quality

  5. Open Circuit Potential • Hi-potential magnesium -1.75V to -1.77V • Standard alloy -1.50V to -1.55V • Open circuit potential is controlled by chemistry and casting process

  6. Current Efficiency • % of energy within the alloy that is available as cathodic protection current • Measured in Amp-Hr/pound • Nominal 50% efficiency for both H-1 and high potential alloys • Determines life of anode • ASTM G97 test (Destructive test, 14 days, $1000 cost

  7. Anode Life Life (yrs) = 0.116 x Wt (lbs) x Efficiency x 0.85 (Utiliz. Factor) Anode Current (amperes)

  8. Value Analysis* *17# anode at 50 mA, Assumes total installed cost of $250

  9. Mag Anode Industry History • Alloy and market development by Dow • Foreign sources (China, Russia, Mexico) entered market in late 90’s • Initial quality problems with foreign anodes • Foreign quality problems resolved by 1999 • US suppliers not competitive with foreign sources • China/Mexico dominant suppliers to US market by 2002

  10. Quality Development of Foreign Sources Early 98 Late 98 1999

  11. 2002/ 2003 Quality Results

  12. 2003 Industry Sampling • 5 high potential anodes obtained on open market in mid-2003 • Tested according to ASTM G97 standard by third-party laboratory • Results confirmed widespread quality problems in industry

  13. 2003 Industry Sample Results Sample OCP vs Current Life* Annual CuCuSO4 Efficiency (yrs) Cost** *17# anode at 50 mA, **Assumes total installed cost of $250

  14. Quality Concern Validation • Anode quality presentation by T. May (MESA) in Oct 2003 w/publication in MP in Jan 2004 • Anode quality presentation by B. Gummow (CORRENG) in Feb 2004 at Northern Area Conference • Anode quality presentation by M. Yunovich (CCTechnologies) in Mar 2004 at Corrosion 2004

  15. 2003 Industry Assessment • Quality concerns apparent in late 2002/2003 • Producers capable, but not providing quality • Diminished user quality control programs • Impact of low quality magnesium not well understood

  16. 2005 Industry Sample Results Sample OCP vs Current Life* Annual CuCuSO4 Efficiency (yrs) Cost** *17# anode at 50 mA, **Assumes total installed cost of $250

  17. 2005 Industry Assessment • Quality of cast anodes is generally improved • Extruded magnesium anodes are quality alternative • No significant changes in end-user QA programs • Still some scrap out there

  18. 2007 Industry Sample Results Sample OCP vs Current Life* Annual CuCuSO4 Efficiency (yrs) Cost** *17# anode at 50 mA, **Assumes total installed cost of $250

  19. 2007 Industry Assessment • Industry sampling validates continuing quality concerns • No significant changes in end-user QA programs • Recent supply instability and price volatility likely to increase quality concerns

  20. End-User Impact OCP vs Current Life* Annual CuCuSO4 Efficiency (yrs) Cost** +$4.70 *17# anode at 50 mA, **Assumes total installed cost of $250

  21. Conclusions • Anode quality continues to be major industry concern • Economic impact to industry estimated at >$2MM per year • End-users and resellers largely unaware or unconcerned of impact of quality • Instability of magnesium market makes overall quality improvement unlikely

  22. Magnesium Anodes Industry Quality Review September 2008 John Cole – MESA Products, Inc.

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