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Low Gassing Secondary Soft Lead

Low Gassing Secondary Soft Lead. Effects of Bismuth, Silver, and Other Impurities R D Prengaman Eco-Bat Group Ulf Buggelsheim Eco-Bat Group. WHO IS ECO-BAT?.

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Low Gassing Secondary Soft Lead

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  1. Low Gassing Secondary Soft Lead Effects of Bismuth, Silver, and Other Impurities R D Prengaman Eco-Bat Group Ulf Buggelsheim Eco-Bat Group

  2. WHO IS ECO-BAT? • We are the world's largest producer of lead with an estimated market share of 19.5% in terms of tonnes oflead sold in Europe, North America and South Africa. • Over 80% of our lead production is recycled lead, which involves the manufacture of refined lead from scrap lead sources, primarily spent lead-acid batteries. • In addition, our South African operations produce zinc, aluminum, industrial minerals, plastics and polyfoams.  • We have 23 operations located in Europe, the United States and South Africa and employ over 2,700 people worldwide. LEADERS IN LEAD

  3. PLANTS IN EUROPE FRANCE STCM Bazoches STCM Toulouse APSM AUSTRIA BMG Arnoldstein GERMANY BBH Stolberg BSB Braubach MRU Freiberg ITALY Eco-Bat Paderno Eco-Bat Marcianese UK HJE LEADERS IN LEAD

  4. PLANTS IN USA USA RSR City of Industry CA RSR Indianapolis IN RSR Middletown NY LEADERS IN LEAD

  5. PLANT IN SOUTH AFRICA SOUTH AFRICA Frys Metals LEADERS IN LEAD

  6. WHAT ARE THE EFFECTS OF IMPURITIESON SOFT LEAD FOR ACTIVE MATERIAL? • To determine the impurity elements most detrimental to gassing and self discharge in soft lead used for oxide, the Advanced Lead Acid Battery Consortium (ALABC) funded a research project at CSIRO to evaluate impurities. • The results of the work showed that Bismuth and silver were beneficial for life and reduced gassing. LEADERS IN LEAD

  7. LEADERS IN LEAD

  8. WHAT ARE THE RESULTS OF THE
ALABC IMPURITIES STUDY ? • Se, Ni, As, Te, Co, Cu, Cr, and Sb are the elements which cause the highesteffects on gassing. Se, Ni, and Te are particularly bad. • Ag, Bi, Zn, Sn, and Cd are considered beneficial and mask the effects of some of the detrimental elements. • Ag, Bi, and Zn are particularly beneficial. LEADERS IN LEAD

  9. SYNERGISTIC EFFECTS Beneficial Detrimental • Hydrogen evolution: Ag, Bi, Cd, Ge, Zn Ni, Se, Te Ag, Bi, Zn • Oxygen evolution: Bi Ni, Se, Te LEADERS IN LEAD

  10. WHICH ELEMENTS REDUCE GASSING? • Only two elements reduce gassing in lead acid batteries. • These elements are Bismuth and zinc. • Silver in combination with Bismuth improves battery life with no increasingof gassing or self discharge. LEADERS IN LEAD

  11. WHAT IS SOFT LEAD USED FOR? • The major use of soft lead today is for the production of lead oxide for use as the active material of lead acid batteries. LEADERS IN LEAD

  12. WHY WAS ONLY PRIMARY LEAD USED FOR ACTIVE MATERIAL IN THE PAST? • For many years primary lead which contained low levels of Bismuth and silver was the only material specified for battery oxide. Primary smelters gave insurance for well equipped refineries and quality control. LEADERS IN LEAD

  13. CAN SECONDARY SMELTERS PRODUCETHE SAME QUALITY TODAY? • Yes. • New refining techniques and analytical instruments has allowed secondary lead producers to produce soft lead with the same gassing and self discharge characteristics as primary lead.All our lead producing sites are certified according to ISO 9000, 14000 and most of them to OHSAS 18000 and EMAS LEADERS IN LEAD

  14. WHAT IS THE USEOF SILVERIN BATTERIES? LEADERS IN LEAD

  15. FOR LEAD CALCIUM TIN SILVER GRID ALLOYS • Pb-Ca-Sn-Ag alloys have been used for positive grids worldwide to improve battery life under high temperature conditions. • These alloys have been used by many battery companies for the last ten years. • RSR Technologies has patented the 007 Pb-Ca-Sn-Ag alloy which is produced by Eco-Bat. LEADERS IN LEAD

  16. WHAT IS THE EFFECT OF SILVER ON THE POSITIVE ACTIVE MATERIAL? • Silver in the (PAM) is transferred to the negative and has no effect on the gassing current of the positive. LEADERS IN LEAD

  17. DISTRIBUTION OF SILVER IN ACTIVE MATERIAL AFTER J240 75C CYCLING Final Silver Content Negative (ppm) Initial Silver Content AM (ppm) Final Silver Content Positive (ppm) 0 1.0 32.8* 50 100 450 1.8 2.1 10.2 117.0 183.0 899.0 * Pb-Ca-Sn-Ag Positive Grids LEADERS IN LEAD

  18. WHAT IS THE EFFECT OF SILVER ON THE NEGATIVE ACTIVE MATERIAL? • No increase in gassing is seen with silver in the negative active material up to 100 ppm. • Silver improves discharge capacity particularly above the 50-100 ppm level. • Silver improves the conductivity and recharge-ability of the negative plate. LEADERS IN LEAD

  19. EFFECT OF SILVER ON DIN CYCLING • Silver DIN H20 • Content Cycles Loss • (ppm) (ml) • 0 180 30 • 50 204 25 • 100 228 30 • 450 276 35 • Barton Pot Oxide • Silver Transfer (ppm) • Initial After Cycling • Start Pos. Neg. • 0 1.6 37.7 • 50 2.3 117.0 • 100 2.9 210.9 • 450 18.0 795.4 LEADERS IN LEAD

  20. WHAT IS THE EFFECT • OF BISMUTH? LEADERS IN LEAD

  21. WHAT IS THE EFFECT OF BISMUTH ONTHE ACTIVE MATERIAL? • Pavlov has shown that Bismuth promotes the rebuilding of contacts in PAM during cycling which promote recharge. • Lam et al. have shown that 500 ppm of Bismuth improves both capacity and recharge of VRLA batteries. • ALABC work shows that Bismuth is the most effective additive to reduce gassing. LEADERS IN LEAD

  22. IS THERE ANY EFFECT OF BISMUTH IN THE ELECTROLYTE? capacity LEADERS IN LEAD

  23. DOES SECONDARY PERFORM LIKEPRIMARY IN GASSING TESTS? • Yes, Secondary lead can have the same or lower gassing characteristics when used as the active material of batteries. • A low impurity well refined secondary marked “Super Secondary” containing 250 ppm Bi and 26ppm silver was compared to 99.99 primary lead with low Bi and Ag. • The secondary out performed the primary. LEADERS IN LEAD

  24. WATER LOSS AT VW GASSING TEST Normal secondary Primary Super Secondary LEADERS IN LEAD

  25. IS THERE AN EFFECT OF BISMUTHON CYCLE LIFE? • Yes, there is a positive effect. • Lead, primary or secondary, containing low levels of gassing impurities was alloyed with Bismuth at a level of 500-600ppm. • This lead was compared to 99.99 primary lead and showed significantly higher cycle life than the 99.99 lead without Bi. LEADERS IN LEAD

  26. ENHANCED VRLA CYCLE LIFE WITHBISMUTH BEARING LEAD LEADERS IN LEAD

  27. OUTCOMES TO DATE • 1. Maximum acceptable levels (MALs) • • Two groups of MALs determined for 16 residual elements: (i) beneficial elements (Sn, Bi, Zn, Cd) at high levels (ii) beneficial elements at ‘normal’ levels • 2. Synergistic effects • • Hydrogen evolution on negative: – masking effects arise from combined action of Bi, Zn, Cd, Ge, Ag – combination of Bi, Zn, Ag gives greatest suppression of gassing – Ni, Te, Se accelerate gassing markedly • • Oxygen evolution on positive: – masking effects arise from combined action of Fe, Sb, Bi – Ni, Te, Se accelerate gassing LEADERS IN LEAD

  28. WHAT IS THE EFFECT OF THE IMPURITIESAS THE TEMPERATURE IS INCREASED? Normal Secondary 99,99 Super Secondary with Bi LEADERS IN LEAD

  29. WHAT IS THE EFFECT OF BISMUTH ANDSILVER ON CORROSION OF GRIDS? • Well refined secondary soft lead can be alloyed with calcium and tin to give the same life as grids produced from low Bi and Ag primary lead. • The next graph shows normal secondary as well as refined secondary compared to primary lead. • The grid corrosion is higher in normal secondary. Well refined secondary despite Bi of 220ppm and Ag of 30ppm (APSM) has the same as primary. LEADERS IN LEAD

  30. CORROSION TEST GRID N04G10 130 PERFORMED BY VARTA LEADERS IN LEAD

  31. WHAT IS THE EFFECT OF Bi AND AgFOR TELECOM GRIDS? • The normal grid alloys for telecom batteries contains low calcium content and 1% tin. • These grids suffer severe corrosion when used in float applications at elevated temperatures of 60C or higher. • Replacing the calcium with 0.02% Bi and up to 0.02% Ag has markedly improved battery life and reduce grid corrosion. LEADERS IN LEAD

  32. INFLUENCE OF Bi AND Ag ON FLOAT LIFE Increased Ag-Bi based on secondary Primary lead with Ca LEADERS IN LEAD

  33. INFLUENCE OF Bi AND Ag ON GRID GROWTH Calcium based on primary High Ag-Bi Based on secondary, no Ca % grid growth cycles LEADERS IN LEAD

  34. WHAT IS THE MAIN DIFFERENCE BETWEEN PRIMARY AND WELL REFINED SECONDARY LEAD? • The major difference between well refined secondarylead and primary lead is the residual content of Bismuth and silver. • 99.99 lead has a Bismuth content of less than 50 ppm and a silver content of less than 15 ppm. These elements are removed by pyro or hydrometallurgical processes. • 99.97 lead typical of secondary lead has silver contents as high as 30-70 ppm and Bismuth contents of 100-300 ppm. LEADERS IN LEAD

  35. CONCLUSIONS • Bi and Ag at low levels (primary lead) was regarded as well refined lead because the refining processes to remove the Ag and Bi also removed gassing impurities. • Today we know which impurity elements cause gassing and self discharge and can be removed from and analyzed in recycled lead. LEADERS IN LEAD

  36. CONCLUSIONS • Secondary lead will make up a larger part of the lead supply for active material in the future as more batteries are recycled. • Secondary lead for active material can and will be refined to remove the gassing impurities but will contain significant amounts of Bismuth and silver. • The higher Bismuth and silver contents will notbe detrimental and will be beneficial to battery performance. • .. LEADERS IN LEAD

  37. THANK YOU FOR • YOUR ATTENTION LEADERS IN LEAD

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