United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-95/007 March 1995
&EPA Project Summary
Recycling of Electric Arc Furnace
Dust: Jorgensen Steel Facility
Trevor W. Jackson and Jamie Sue Chapman
The Ek Glassification™* process was
evaluated under the Waste Reduction
Innovative Technology Evaluation
(WRITE) Program, a formal program
established by the United States Envi-
ronmental Protection Agency (EPA) to
accelerate the development of new and
innovative technologies used to recycle
or reduce waste and pollution., The pro-
cess has potential to effectively reduce
hazardous waste generated in the steel-
making industry (K061-listed waste,
defined as "emission control dust/
sludge from the primary production of
steel in electric furnaces," 40 CFR
261.32) by recycling Electric Arc Fur-
nace (EAF) dust and converting it into
usable products.
An economic assessment was made
of applying this process to a plant pro-
ducing approximately 21,000 tons of
product/yr. These estimates indicate
that a profitable operation is possible.
Products range from $2/ton (Portland
cement materials) to $650/ton (glass
ceramics/ architectual tile feedstocks).
Air emissions and process wastewa-
ter were not analyzed for this test. For
full scale applications these may need
to be investigated under actual operat-
ing conditions.
This Project Summary was developed
by EPA's Risk Reduction Engineering
Laboratory, Cincinnati, OH, to announce
key findings of the research project
that is fully documented in a separate
" Mention of trade names or commercial products does
not constitute endorsement or recommendation for
report of the same title (see Project
Report ordering information at back).
Introduction
The steel-making industry produces a
large amount of Electric Arc Furnace (EAF)
dust as part of normal production. A glass
technology called Ek Glassification™
(hereafter called "the Process") has been
developed by Roger B. Ek and Associ-
ates, Inc. (hereafter called "the Developer")
to recycle this listed waste (K061) and
convert it, along with other byproducts of
the steel-making industry (i.e., spent steel
slags, spent refractories, mill scale, and
grinding swarf), into marketable commodi-
ties that are defined as nonleachable by
Toxicity Characteristic Leaching Procedure
(TCLP) protocols. These products may in-
clude colored glass and glass-ceramics;
ceramic glazes, colorants, and fillers; roof-
ing granules and sand-blasting grit; and
materials for Portland cement production.
For this project, a portable pilot-scale
process furnace was utilized (see Figure
1). Natural gas burners were used to heat
the furnace to its operating temperature of
approximately 2,500°F. The furnace was
also equipped with molybdenum metal
electrodes for partial or complete electric
heating. The use of natural gas results in
volatilized metal emissions whose levels
are regulated. Electrical resistance heat-
ing using electrodes is the preferred
method of supplying heat to the furnace
once the glass has become molten. This
is because of better heat transfer between
the electrodes and the melt and because
no additional volume of pollutants are gen-
Printedon Recycled Paper
-------
Exhaust
port
Glass batch
port
Furnace refractory lining
-------
The crushed and screened materials
were placed in steel drums and plastic
pails, labeled, and covered. Weighing was
performed on a 3 ft2 platform scale with a
capacity of 5,000 Ib.
Each ingredient for the 260-lb batch
was weighed in a 5-gal plastic pail and
added to a paddle mixer equipped with
plow blades intended for dry mixing of
refractory castables. The blender was cov-
ered and sealed to eliminate fugitive dust
emissions. Blending was carried out for at
least one minute in accordance with
blender manufacturer's recommendations,
followed by visual inspection for homoge-
neity. To avoid contamination of the
blender with EAF dust, the dust
componentwas hand-blended into the
batch just prior to loading into the furnace.
The furnace was charged with a steel
shovel. At the start of charging, particu-
late emissions were very noticeable in the
furnace stack. However, once the glass
batch covered the molten glass surface to
a depth of about one inch, the visible
emissions diminished rapidly.
The furnace was located in the steel-
melting area of the EMJ plant so that
fugitive emissions could be collected with
the steel plant's dust collection system
and routed to the baghouse.
Gas burners were used to bring the
furnace up to operating temperature (2,400
to 2,500°F). This operation required ap-
proximately 12 hr. Once the operating tem-
perature was reached, the glass batch
was added. Approximately 1-1/2 hr were
required to load one batch. At the comple-
tion of loading the batch, electrode tests
were conducted intermittently. The elec-
tric heating system utilized two commer-
cial-sized, 1-1/4-in. diameter molybdenum
electrodes. The testing used natural gas
as the primary melt energy. The purpose
of the electric melting tests was to estab-
lish melt conductivity, measure the am-
perage flow at constant voltage and select
glass temperature isothermal conditions.
These data were used to determine the
specifications for transformer equipment
(especially the operating voltage range) to
be used in full-scale operations. The elec-
trodes also provided heat to maintain the
furnace temperature between 2,400 and
2,500°F. Each batch produced about 250
to 300 Ib of molten product. Approximately
30 min were required to ladle the glass
into moulds. At the end of the day, the
furnace temperature was dropped slightly
and maintained between 2,200 and
2,300°F during the night.
The Glass II recipe was sampled and
analyzed as part of the EPA testing activi-
ties. This recipe was used to prepare glaze,
iron silicate for Portland cement produc-
tion and sandblasting grit. For the castable
product, the glass was poured into a 6-in.
diameter disc mold to a depth of approxi-
mately 2 in. and allowed to cool into a
solid monolith. For the granular product,
the molten glass was quenched with wa-
ter as it was poured into a storage vessel.
Quenching of the molten glass produced
a granular material known as "frit."
Duplicate samples of both a castable
product and a granular product were col-
lected at the end of the day of testing. For
the castable product, the solid monolith
was fractured into small pieces (no greater
than 1 in. in diameter) by placing the mono-
lith of glass on a hard surface and striking
the disk with a heavy object. Samples
obtained were split for analysis by both
EPA's laboratory (NET Pacific, Inc.) and
the Developer's laboratory (Sound Ana-
lytical Services, Inc.) and placed in 1-L
glass jars.
For the case of the granular product,
the complete batch of product was manu-
ally homogenized using a drum and stain-
less steel trowel. Representative aliquots
were then obtained from various random
locations within the drum, split for analysis
by the two laboratories, and placed into
1-L glass jars.
Process monitoring and furnace operat-
ing parameter data were gathered by the
Developer. The primary granular, and a
composite of the castable samples were
subjected to the TCLP in accordance with
SW-846 Method 1311 and subsequently
analyzed for eight RCRA metals plus zinc.
Results and Discussion
Samples analyzed by NET Pacific for
EPA indicated low teachability character-
istics for metals in the final products as
shown in Table 1. The leachable metal
content in both the castable and the granu-
lar samples was within the TCLP limits for
all compounds for which they were ana-
lyzed. Barium, chromium, lead, and zinc
were the only compounds detected in ei-
ther of the EPA samples. Comparison of
these data to those obtained by Sound
Analytical Services, Inc. (see Table 1) pro-
duced similar results (for the granular prod-
uct only) even though the Developer's
laboratory could not achieve the same
detection limits as the EPA laboratory.
TCLP analyses were performed on
Glasses I and III by the Developer's labo-
ratory. The results of these analyses indi-
cated that the products are within the TCLP
leaching maximums.
Stack gas sampling data were previ-
ously gathered during earlier tests at the
Oregon Steel Mill (OSM). Although these
data suggest acceptable air emissions,
the data are of questionable quality be-
cause they do not satisfy EPA stack test-
ing protocols and standards.
Cost estimates were performed for the
OSM plant. A full-scale system producing
60 tons of glass/day, and operating 350
Table 1. TCLP Results and Comparison to Regulatory Limits for Samples from EMJ
EPAHWNo.'
1
2
D004
D005
D006
D007
D008
D009
D010
D011
Hazardous
Av&rant* nf
Contaminant
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Selenium
Silver
Zinc
Waste Number
fit /ri/lV'ofo oomn/iao
EPA Castable
Sample2
(mg/L)
<0.0025
0.043
<0.0035
0.050
0.067
<0.000086
<0.001
<0.0092
0.95
EPA Granular
Sample2
(mg/L)
<0.0025
0.025
<0.0035
0.13
0.120
<0.000086
<0.001
<0.0092
0.60
Developer
Granular
Sample (mg/L)
<0.2
<0.1
<0.1
0.1
<0.1
<0.002
<0.3
<0.1
0.6
Regulatory
LeveP (mg/L)
5.0
100.0
1.0
5.0
5.0
0.2
1.0
5.0
NR
3 Regulatory levels taken from 40 CFR ch. 1 (7-1-90 Edition), Section 261 24 Table 1
NR Not Regulated
-------
days/yr would require an initial cost of
$10,500,000 for design, construction and
start up.
For a 10 yr period, the Process could
produce a gross profit of $63,195,000 while
avoiding $43,040,000 in disposal costs,
for a total savings of $106 million, not
including reduced liability benefits, and
avoidance of administrative costs for per-
mits and managing of hazardous waste
under the old system.
The actual savings realized will depend
on the types and amounts of products
sold (at present market conditions, the
lowest value products are cement addi-
tives at $2 to $6/ton. The highest value
products, such as glass ceramics and ar-
chitectural tiles sell from $175 to $6507
ton.
Conclusions
A number of conclusions may be drawn
regarding the Process as a result of this
study:
• The glass product types which were
prepared by the Process and tested
as part of this study resulted in
relatively non-leachable glasses. For
the metals of interest for K061 waste
(calcium, chromium, and lead), these
values were lower than those allowed
under RCRA regulations for TCLP.
• The Process utilizes other (non-listed)
foundry wastes to replace constituents
that would be purchased as virgin
additives for glass-making. Ideally this
results in both a .conservation of
Trevor W. Jackson and Jamie Sue Chapman are with Science Applications
International Corporation, San Diego, CA 92121
Ivars Lids Is the EPA Project Officer (see below).
The complete report, entitled "Recycling of Electric Arc Furnace Dust:
Jorgensen Steel Facility," (Order No. PB95-167219; Cost: $19.50, subject
to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
resources and recycling of both
hazardous and non-hazardous wastes
at the foundry.
• This project did not focus on
investigating compliance issues in
terms of air emissions and waste
water generated during batch
charging, melting, quenching and
drying of the three glass products. It
is believed that significant variation in
emission species and concentrations
are possible, due to the specific
application and associated operational
procedures.
Compliance issues should be evaluated
on a case-by-case basis at least until full-
scale data are accumulated to better iden-
tify the variability- associated with applying
this technology.
The full report was submitted in fulfill-
ment of contract 68-C8-0062, WA 3-18
SAIC under the sponsorship of the U.S.
Environmental Protection Agency.
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penally for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/SR-95/007
------- |