United States
 Environmental Protection
 Agency
 Industrial Environmental Research
 Laboratory
 Research Triangle Park NC 2771 1
 Research and Development
 EPA-600/S2-81-036 July 1981
 Project Summary
 Hot  Metal  Desulfurization,
 BOF  Charging,  and  Oxygen
 Blowing:  Level  1
 Environmental  Assessment
C  W Westbrook
  An EPA/IERL-RTP Level 1 environ-
 mental assessment of fumes generated
 at one plant during external hot metal
 desulfurizaton (HMDS), hot metal
 charging to the basic oxygen furnace
 (BOF), and during oxygen blowing of
 the BOF was performed. The purpose
 of the work was to develop prelimi-
 nary  information on the organic and
 inorganic matter generated in these
 processes.
  Fumes generated (before emission
 control) during HMDS contain about
 0.64  kg of particulate and 1 x 10 3 kg
 of organic/Mg of metal desulfurized
 (1.27 and 2 x 10~3Ib/ton, respectively).
 Although a small amount of possibly
 carcinogenic polynuclear aromatic
 hydrocarbons (PNA) were detected,
 none of the organic categories was
 found in sufficiently high concentra-
 tion to be of environmental concern.
 Sufficiently high concentrations of
 some metals (e.g., lead, mercury,
 antimony, and arsenic) were found to
 require highly efficient dust capture
 and environmentally sound disposal.
  Fumes generated (before control)
 during BOF hot metal charging con-
 tain about 5.3 x 10 2 kg of particulate
and 5.8 x 10~4 kg of organic/Mg (of
 hot metal charged (10.6 x 10 2 and
 11.6 x 10~" Ib/ton, respectively). No
 PNA  was detected and none of the
organic category concentrations is
high enough for environmental con-
 cern. Sufficiently high concentrations
 of some metals (e.g., arsenic, lead.
 mercury, and cadmium) were found to
 require good dust capture and disposal.
 Dust from the BOF baghouse, which
 collects fumes from hot metal transfer
 and charging, scrap charging, tapping,
 and slagging, also contained about
 100 mg PNA/kg (0.2 Ib/ton) of dust.
 The source of the PNA was not deter-
 mined.
  About 11 kg of particulate  and
 0.004 kg of organic/Mg of steel (22
 and 0.008 Ib/ton, respectively)
 processed in the BOF is captured by
 the primary emissions control scrubber
 during the  oxygen blow period. Al-
 though no PNA was found in the
 scrubber water, a small amount (<1
 mg/kg solids) was found in the solids
 removed from the primary clarifier.
 None of the organic concentrations is
 high enough for environmental con-
 cern.  The concentrations of lead,
 selenium, manganese, copper,  and
 zinc in the clarified recycle water
 would be of concern if discharged to
 surface waters.
  This Project Summary was devel-
 oped by EPA's Industrial Environ-
mental Research Laboratory, Research
 Triangle Park, NC, to announce  key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).

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Introduction
  This report describes the results of an
EPA/IERL-RTP Level 11  assessment of
fumes generated at one plant (Kaiser
Steel Company, Fontana,  CA) in three
phases of the manufacture of steel. The
Level 1 approach, which measures
particulates, inorganics, and organics,
is a unified approach designed to indicate
whether or not significant amounts of
hazardous materials may be generated,
and possibly emitted, by a  process. The
data  obtained are useful  in assessing
potential environmental problems and
allow priorities  for future research
efforts to be established.
  The purpose of this study is to deter-
mine if the processes involved, rather
than the plant as a whole,  are potential
generators of hazardous materials.
Therefore, this work concentrates pri-
marily on characterization  of the fumes
generated by the processes rather than
on measuring discharges  to the envi-
ronment  As such,  the  results can be
extrapolated, with appropriate caution,
to similar processes at other plants.
  The processes included  in this study
are external desulfurization of molten
metal produced by the  blast furnace,
charging of hot metal  into the basic
oxygen furnace (BOF), and oxygen
blowing of the BOF .
Summary
  Sampling and analysis of fumes
generated during external desulfuriza-
tion  of blast-furnace-produced hot
metal, during hot metal  addition to the
basic oxygen furnace (BOF), and during
oxygen blowing of the BOF at the plant
were conducted. EPA/ IERL-RTP Level
1 protocols1 were  used.  Statements
regarding the degree of environmental
concern are based on comparison of the
data obtained  with published  MEGs
data.2

Hot Metal Desulfurization
  Molten metal produced  by the blast
furnace is cast into torpedo rail-cars. If
the metal sulfur content exceeds desir-
able  levels for specific further process-
ing,  the sulfur is removed from the
metal, while still in the torpedo car, at
the hot metal desulfurization station
(HMDS). To accomplish this, appropriate
amounts of calcium carbide (CaCa) and
calcium carbonate  (CaCOs) are blown
into the metal (with nitrogen gas) through
a lance submerged in the metal. Fumes
generated in the process are  collected
by side-draft hoods and collected  in a
baghouse.  One to  three  cars can be
desulfurized simultaneously. All side-
draft hoods operate during desulfuriza-
tion regardless of the number of cars
being processed.
  The Source Assessment  Sampling
System (SASS) was used to collect
samples during four periods of desulfu-
rization. The sample was taken in the
duct before the fume entered the bag-
house and, thus, represents the amount
of fumes generated by the process and
not the amount emitted to the environ-
ment. A sample of the dust collected by
the baghouse was also obtained and
analyzed.
  Table 1 isasummaryoftheparticulate
and total organic matter results.
BOF Hot Metal Charging
  After scrap metal is charged into the
BOF vessel, molten iron is added. The
fumes generated during this addition
are collected by two side-draft hoods
and captured in a  baghouse. The bag-
house also captures fumes generated
           during hot metal transfer,  reladling,
           scrap charging, tapping, and slagging.
             Samples were taken from one of the
           charging fume control dusts with the
           SASS train. Twenty-four periods of hot
           metal charging were sampled to obtain
           a reasonable amount of sample. Since
           the SASS train was not "cleaned up"
           (samples recovered) between runs, data
           for individual charges were not obtained.
           Also obtained and analyzed was a
           sample of the dust collected by the
           baghouse. Results from this sample
           cannot be compared to the SASS train
           samples since fumes from other sources
           enter the baghouse.
             Given m Table 2  are the results
           obtained for particulates and total
           organics.

           BOF Oxygen Blowing
             After hot metal is charged, oxygen is
           blown into the vessel (fluxes are  also
           added) to reduce the carbon content and
           produce steel. At Kaiser, a suppressed
           combustion system is used and results
Table 1.     HMDS Total Paniculate and Organic Matter Summary


    Sample Type
Concentration in Gas
     mg/Nm3
       Generated,
kg/Mg Steel Desulfurized
 A.  Paniculate
    Probe, cyclone washes
    >10 /j cyclone dust
    >3 (i cyclone dust
    >1 fj cyclone dust
    <1 [i dust (filter)
          TOTAL:
        175
       3123
       1754
        900
        298
       6250
         0.018
         0.318
         0.179
         0.092
         0.030
         0.637
 B.  Organic
    All particulates
    Organic module
         TOTAL:
        3.8
        9.9
      3.87 x 10'
      6.21 x 10'
      1.01 x 10'
Table 2.    BOF Hot Metal Charging Paniculate and Organic Summary
Concentration in Gas
Sample Type mg/Nm3
A.
B.
Paniculate
Probe, cyclone washes
>10 /J cyclone dust
>3 (j cyclone dust
>1 (j cyclone dust
<1 it dust (filter)
TOTAL:
Organic
All particulates
Organic module
TOTAL:
98.6
274.0
205.8
123.9
85.1
787.4
0.7
7.9
8.6
Average Generated,
kg/Mg Hot Metal Added
6.65 x 10'3
1.85 x 10'2
1.40 x 10'2
8.42 x 10'3
5.77 x 10'3
5.33 x 10'2
4.7 x 10'5
5.4 x 10'* i
5.8 x 10'*

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 in gas produced during oxygen blowing
 with a high (>20 percent) carbon mon-
 oxide content. Direct sampling of the
 gas was not done. The gas produced is
 cleaned  in a  scrubber. Samples of the
 water going  to and coming from the
 scrubber and solids removed  from the
 water treatment clarif iers were obtained
 and analyzed. The results are given  in
 Table 3.

 Conclusions
  1. Fumes generated (before emission
    control) during external hot metal
    desulfurization (HMDS) contain
    about 0.64 kg of paniculate and 1 x
     10"3 kg of organic/Mg (1.27 and 2 x
     1CT3 Ib/ton, respectively)  of metal
    desulfurized.
  2. Organics in the HMDS fumes are
    predominately aliphatic hydrocar-
    bons, ethers, ketones, and  esters.  A
    small amount of  polynuclear aro-
    matic hydrocarbons (possibly in-
    cluding some carcinogens) was
    detected. None of the organic cate-
    gory concentrations are high enough
    to be of environmental concern.
  3. Significantly high concentrations of
    lead, mercury, barium, antimony,
    strontium, arsenic, copper, manga-
    nese, and chromium were found in
    the HMDS fumes. It is important
    that  fume collection and baghouse
    dust collection efficiency be high.
  4. Dust captured by the HMDS bag-
    house is sufficiently high in content
    of strontium, chromium, and arsenic
    to be of concern for landfill disposal.
    (The dust is recycled at the plant
    tested.)

  5. Only about 10 percent of the organic
    matter generated by HMDS is cap-
    ture  by the  baghouse.

  6. Fumes generated (before emission
    control) during hot metal charging
    to  the basic oxygen furnace (BOF)
    vessel contain about 5.3 x 10~2 kg of
    paniculate and 5.8 x KT4 kg of
    organic/Mg (10.6 x 10"2 and 11.6 x
    10 4 Ib/ton,  respeci.vely) of hot
    metal charged.
           7. Organics in  the  BOF  hot  metal
             charging fumes are predominately
             esters, ketones, and ethers. The
             concentrations found at this plant
             are not high  enough for environ-
             mental concern.

           8. Significantly high concentrations of
             strontium, selenium, arsenic, cop-
             per, chromium, lead, mercury, bar-
             ium, antimony, and cadmium were
             found in the BOF hot metal charging
             fumes. It is important  that fume
             collection and capture efficiency be
             high.
           9. Dust captured by the BOF secondary
             emissions control baghouse is suffi-
             ciently high in content of the metals
             cited in 8 above to be of concern for
             landfill disposal. (The dust is recycled
             at the plant tested.)

          10. The organic content of the BOFbag-
             house dust was about 540 mg/kg
             (1.1 Ib/ton) of dust. As much as 20
             percent  of the organic could be
             polynuclear aromatic hydrocarbons,
             and  could  include some known
             carcinogens. This suggests possible
             environmental problems with the
             disposal of  the dust and indicates
             that the baghouse outlet should be
             tested to determine PNA emissions.

          11. About 11 kg of paniculate and
             0.004 kg of organic/Mg (22 and
             0.008 Ib/ton, respectively) of steel
             processed in the BOF is captured by
             the primary  emissions control
             scrubber during the oxygen blowing
             period.

          12. Organics in the BOF scrubber water
             were mostly silicones, ethers, alco-
             hols, ketones, and similar com-
             pounds. No PNA was found  in the
             scrubber  water; however, a  small
             amount (<1 mg/kg solids) of PNA
             was found m  solids removed from
             the primary clarifier.  None of the
             organic categories, in  either the
             clarified recycle water or scrubber
             discharge water,  was in sufficient
             concentration to be of environmen-
             tal concern.
Table 3.    BOF Oxygen Blowing Water Treatment Samples
 Sample Type
In Sample, kg/min
Solids      Organic
kg/Mg Steel Processed
  Solids      Organic
 Scrubber discharge water        137        0.36
 Recycle water                     1.5       0.32
 Net Captured                                            11        0.004
 Primary clarifier solids = About 7.1 mg organic/kg solids.
 Secondary clarifier solids = About 66.1 mg organic/kg solids.
 13 The concentrations of lead, sele-
    nium, manganese, copper, and zinc
    in the clarified water  would be of
    concern if discharged to surface
    waters. (This water is totally recycled
    at the plant tested.)

 Recommendations
   Although organic matter  is generated
 during hot metal desulfurization and the
 data  indicate a substantial fraction
 (possibly >90 percent) of the organic is
 not captured by the baghouse, the low
 concentrations  found indicate that no
 additional work in  this area is needed.
 Significantly high concentrations of
 some metals (including lead, mercury,
 antimony, and arsenic) were found in
 the fumes generated and dust captured.
 Additional  testing  (e.g., leaching)  may
 be needed to assess the degree of
 hazard  if the dust is  landfilled,  rather
 than recycled as for the plant tested.
   The data suggest that additional work
 may be needed to assess BOF secondary
 fume  generating processes (hot metal
 transfer, scrap charge, tapping, etc.) and
 possibly emissions from this source.
 About 100 mg PNA/kg secondary emis-
 sion control baghouse dust was  found,
 but PNAs were not detected in  fumes
 from hot metal charging. Testing should
 include further  analysis  of the dust to
 determine if it constitutes a hazardous
 waste, testing of each process step to
 determine which is generating the PNA,
 and testing  of the baghouse outlet to
 determine if unacceptable  amounts of
 PNA are being released to the environ-
 ment. Significant amounts of  some
 metals (e.g., arsenic, chromium, lead,
 antimony, and cadmium) were found in
 both the hot metal  charging fumes and
 in the secondary  emissions control
 baghouse dust.
  The data suggest that little organic
 matter is generated during  BOF oxygen
 blowing. No additional testing in this
 area  is recommended. The clarified
 scrubber water (recycled at the plant
 tested) contains sufficiently high con-
 centrations of lead, selenium,  manga-
 nese,  copper, and zinc to present prob-
 lems if discharged to surface  waters.
 More  accurate quantitation of the con-
 centrations and  masses generated may
 be needed for plants where  the water is
discharged rather than recycled.


References
 1. Lentzen, D. E., D. E. Wagoner, E. D.
   Estes, and W. F. Gutknecht.  IERL-
   RTP Procedures Manual: Level 1
* US GOVERNMENT PRINTING OFFICE 1961 -757-012/7227

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       Environmental Assessment-Second
       Edition. EPA-600/7-78-201 (NTIS
       No. PB 293795), October 1978.
       Kingsbury, G. L, R. C. Sims, and J. B.
       White. Multimedia Environmental
       Goals for Environmental Assess-
       ment-MEG Charts and Background
       Information  Summaries—Vol.Ill-
       Categories 1-12, EPA -600/7-79-
       176a (NTIS No. PB 80-115108), and
       Vol IV—Categories  13-26, EPA-
       600/7-79-1 76b (NTIS No. PB 80-
       115116), August 1979.
           C. W. Westbrook is with Research Triangle Institute, Research Triangle Park NC
             27709.
           R. C. McCrillis is the EPA Project Officer (see below).
            The  complete report, entitled "Hot Metal Desulfurization, BOF Charging, and
              Oxygen Blowing. Level! Environmental Assessment, "(Order No. PB 81-179 251;
             Cosf $12 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.
                   Industrial Environmental Research  Laboratory
                   U S  Environmental Protection Agency
                   Research Triangle Park, NC 27711
                                                                                                                      i
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
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Penalty for Private Use S300

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