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Mercury Contamination from Metal Scrap Processing Facilities – A Study by Ohio EPA

Explore Ohio EPA's study on mercury emissions from metal scrap processing facilities, focusing on mercury switches and environmental impacts.

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Mercury Contamination from Metal Scrap Processing Facilities – A Study by Ohio EPA

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  1. Mercury Contamination from Metal Scrap Processing Facilities – A Study by Ohio EPA Radhica Sastry, James Orlemann and Paul Koval – Ohio EPA Presented by Radhica Sastry

  2. Origin Hg occurs as a mineral oar called cinnabar (mercury (II) sulfide) Extracted by heating mercury (II) sulfide in air to form mercury (II) oxide Only metal that is a liquid at room temperature Applications Lighting devices Dental amalgam Switching devices Measuring devices Mercury Origin & Applications

  3. Mercury Toxicity • Persistent toxic substance • Extremely volatile • Bacteria convert mercury into methyl mercury and bioaccumulates in living organisms • Accumulates in brain cells • Symptoms include headache, numbness, balance problems, etc.

  4. Mercury in the Environment

  5. Anthropogenic Emissions • Mercury production • Mercury from manufacturing/combustion • Chlor-alkali plants • Coal combustion • Mercury from disposal • Incineration • Mercury from recycling • Scrap processing

  6. Scrap Processing • Mini-mills mainly use metal scrap to produce steel • Scrap comes from recycling facilities • End-of-Life Vehicles are sent to auto-dismantling yards • Autos are shredded/crushed • Processed scrap sent to mini-mills to be melted • Main concern is Mercury Switches in the scrap!!

  7. Life Cycle of a Mercury Switch

  8. Mercury Switches • What are mercury Switches? • Tilt switches that use mercury to make contact

  9. Where are mercury switches used? Chest freezers Sump pumps Clothes washers Automobiles Clothes irons Space heaters Why are they used? Hermetically sealed construction Consistent operation High load capability Moderate cost Available in different shapes, sizes and electrical ratings Mercury Switches - Uses

  10. Mercury Switches • Most vehicles equipped with mercury switches • Applications are: • Trunks & Hoods • ABS systems • HID lamps • Each switch contains 0.8-1 gram Hg. • U.S. auto industry uses ~ 22,000 lbs. Hg each year (1995 industry report)

  11. Ohio EPA’s Initiative • Enforcement case revealed high amounts of mercury emissions from a mini-mill • Studies were conducted to determine source of mercury emissions using different scrap types • Results from tests show correlation between melting of shredded scrap and No. 2 bundles and amount of mercury emissions • Results prompted Ohio EPA to conduct studies at other facilities

  12. Scrap Grades

  13. Scrap Type Normal A B C D E F Shredded (frag) 20 30 30 10 10 0 0 Bundles 2 10 0 0 25 0 0 20 Correlation between type of scrap & mercury emissions

  14. Details of study • Survey questionnaire sent to 70 facilities operating electric arc furnaces /cupolas/induction furnaces • Type of scrap melted and the amount • Amount of scrap melted per heat • Response received from 52 facilities • 7 facilities were using shredded scrap and/or No. 2 bundles while remaining 45 used different type of scrap • Letters were sent to these 7 facilities requesting them to test for mercury emissions

  15. Survey Results

  16. Stack test results • Out of 7 facilities, 5 were mini-mills; 2 were foundries • 1 facility claimed bankruptcy • 2 submitted test results conducted 2 years ago • 2 facilities conducted the test • 2 foundries refused to test

  17. Stack Test Results Facility D • Av amt of frag used = 31,345 lbs/heat • Steel tonnage rate during test ~ 40 tons/hr. • Max. capacity ~ 110 tons/hr. • Extrapolating for max capacity conditions: • Amt of frag = 43,970 lbs/hr • Amt of Hg. ~ 0.029 lbs/hr.

  18. Conclusions & Future Steps • Definite increase in mercury emissions when shredded scrap is melted • Mercury switches are a significant source of high mercury emissions • Future study will include shredding facilities • Ohio is looking into starting a mercury switch removal program • We are envisioning that we will get same facilities to re-test

  19. Questions/Ideas?

  20. Thank youContact detailsradhica.sastry@epa.state.oh.us(614) 728-1354

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