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

Division of Air Pollution ControlJune 25, 2001

Mercury Contamination from Metal Scrap Processing Facilities –

A Study by Ohio EPARadhica Sastry, James Orlemann and

Paul Koval – Ohio EPA

Presented byRadhica Sastry


Mercury Origin & Applications• 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 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.


Mercury in the Environment


Anthropogenic Emissions • Mercury production

• Mercury from manufacturing/combustion – Chlor-alkali plants– Coal combustion

• Mercury from disposal– Incineration

•Mercury from recycling

–Scrap processing


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!!


Life Cycle of a Mercury Switch


Mercury Switches• What are mercury Switches?

– Tilt switches that use mercury to make contact


Mercury Switches - UsesWhere 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 • 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)



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


Scrap Grades

Scrap Grade Description

Shredded scrap Homogenous iron and steel scrap, originating from automobiles, miscellaneous bailing and sheet scrap.

Bundled No. 2 Wrought iron or steel scrap, black or galvanized. Auto body and fender stock may constitute a maximum of 60% by weight

Shredded auto* Auto scrap that is shredded


Correlation between type of scrap & mercury emissions

0.07470.0716

0.0464

0.0160.0222 0.0247 0.0254

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

Type of scrap

Am

t. of

Hg.

em

issi

ons

(lbs/

hour

)

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


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


Survey Results FACILITY Furnace # No. 1 Shredded No. 2 Heavy No. 2 BundlesNo. 2 Shredded Shredded

NAME (tons/yr) Melt (tons/yr) (tons/yr) (tons/yr) Auto (tons/yr)Facility A A - 1 0 53,200 3,700 0 9,000

B - 1 0 19,946 0 240,277 30,000Facility B B - 2 0 0 0 52,130 0

B - 3 0 0 0 52,130 0

Facility C C - 1 28,908

C - 2

Facility D D - 3 3,840 5,648

D - 4 92,160 135,544

Facility E E - 1 39,559

(foundry) E - 2 11,817Facility F F - 1 300,000 0 0 436,000 0

G - 1 1,462

Facility G G - 2 21,159

(foundry) G - 3 33,450

G - 4 30,877


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


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.

Facility D - Stack Test

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

Run 1 Run 2 Run 3Run #

Am

t. of

Hg.

(lbs

/hr)

19,208 lbs/hr

0 lbs/hr

21,317 lbs/hr


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


Questions/Ideas?


Thank you

Contact details

[email protected](614) 728-1354

Documents

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