-------
TABLE X-2
ALTERNATIVE EFFLUENT LIMITATIONS
90% RECYCLE DISCHARGE ALTERNATIVE
i • ••
Subpart A - Aluminum Casting Subcategory
(a) Casting Quench Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kq/kkq (lb/1000 Ib) of Metal Poured
0.000124 0.0000512
(b) Die Casting Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Acenaphthene
2,4,6-trichlorophenol
Parachlorometacresol
Chloroform
Phenol
Butyl benzyl phthalate
Chrysene
Tetrachloroethylene
Lead
Zinc
Phenols (4AAP)
kg/kkq (lb/1000 Ib) of Metal Poured
0,
0,
0,
0,
0.
0.
0.
0.
0.
0.
0000184
0000610
0000561
000134
0000126
000207
0000039
0000523
0000484
000494
0.000215
0.0000092
0.0000305
0.0000281
0.0000668
0.0000063
0.000104
0.0000019
0.0000261
0.0000436
0.000203
0.000107
940
-------
(c) Die Lube Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
ka/kkq (lb/1000 Ib) of Metal Poured
2,4,6-trichlorophenol
Chlorofoorm
Phenol
Butyl benzyl phthalate
Tetrachloroethylene
Copper
Lead
Zinc
Phenols (4AAP)
0
0
0
0
0
0
0
0
0000012
0000026
,0000002
,0000041
,0000010
,0000123
.0000010
.0000098
0.0000043
Subpart B - Copper Casting Subcategory
(a) Dust Collection Operations
0.0000006
0.0000013
0.0000001
0.0000021
0.0000005
0.0000059
0.0000009
0.0000040
0.0000021
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Copper
Lead
Zinc
ka/kkq (lb/1000 Ib) of Sand Handled
0.000110
0.0000086
0.0000877
0.0000524
0.0000077
0.0000361
941
-------
(b) Mold Cooling and Casting Quench Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
kg/kkq (lb/1000 Ib) of Metal Poured
Copper
Zinc
0.000603
0.000481
0.000288
0.000198
Subpart C - Ferrous Casting Subcategory
(a) Dust Collection Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
kg/kkq (lb/1000 Ib) of Sand Handled
Copper
Lead
Zinc
0.0000748
0.0000058
0.0000596
0.0000356
0.0000053
0.0000245
(b) Melting Furnace Scrubber
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Copper
Lead
Zinc
kg/kkq (lb/1000 Ib)
0.000694 ;
0.0000542
0.000553 ......
of Metal Poured
0.000331
0.0000488
0.000228
942
-------
(c) Slag Quench Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum (for
Monthly Average
Copper
Lead
Zinc
ka/kkq (lb/1000 lb) of Metal Poured
0.000192
0.0000150
0.000153
0.0000916
0.0000135
0.0000631
(d) Casting Quench and Mold Cooling Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
ka/kkq (lb/1000 lb) of Metal Poured
Copper1
Lead1
Zinc1
0.000117
0.0000092
0.0000936
0.0000560
0.0000083
0.0000385
These limitations would be applicable only when casting
quench and mold cooling wastewaters are treated with other
ferrous subcategory process wastewaters.
(e) Sand Washing Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Copper
Lead
Zinc
ka/kkq (lb/1000 lb) of Sand Handled
0.0005980.000285
0.0000467 0.0000421
0.000477 0.000196
943
-------
Subpart D - Lead Casting Subcategory
(a) Grid Casting Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Lead
kq/kkq (lb/1000 Ib) of Metal Poured
0.0000023 ; 0.0000020
(b) Melting Furnace Scrubber Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Lead
kq/kkq (lb/100 Ib) of Metal Poured
0.0000308 0.0000277
Subpart E - Magnesium Casting Subcategory
(a) Grinding Scrubber Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kq/kkq (lb/1000 Ib) of Metal Poured
0.000681 , 0.000280
944
-------
(b) Dust Collection Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kq/kkq (lb/1000 Ib) of Sand Handled
0.0000094 0.0000039
Subpart F - Zinc Casting Subcategory
(a) Die Casting and Casting Quench Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kq/kkq (lb/1000 Ib) of Metal Poured
0.0000170 0.0000070
(b) Melting Furnace Scrubber Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
Phenols (4AAP)
kq/kkq (lb/1000 Ib) of Metal Poured
0.000321
0.00315
0.000132
0.00157
945
-------
TABLE X-3
ALTERNATIVE EFFLUENT LIMITATIONS
50% RECYCLE DISCHARGE ALTERNATIVE
Subpart A - Aluminum Casting Subcategory
(a) Casting Quench Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kg/kkg (lb/1000 lb) of Metal Poured
0.000621 . 0.000256
(b) Die Casting Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
kg/kkg (lb/1000 lb) of Metal Poured
Acenaphthene
2,4,6-trichlorophenol
Parachlorometacresol
Chloroform
Phenol
Butyl benzyl phthalate
Chrysene
Tetrachloroethylene
Lead
Zinc
Phenols (4AAP)
0.0000920
0.000305 ;
0.000281
0.000668
0.0000629
0.00104
0.0000194
0.000261
0.000242 '
0.00247
0.00107
0.0000460
0.000152
0. 000140
0.000334
0.0000315
0.000518
0.0000097
0.000131
0.000218
0. 00102
0.000537
946
-------
(c) Die Lube Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
2,4,6-trichlorophenol
Chloroform
Phenol
Butyl benzyl phthalate
Tetrachloroethy1ene
Copper
Lead
Zinc
Phenols (4AAP)
ka/kkq (lb/1000 lb) of Metal Poured
0000060
0000132
0000012
,0000205
,0000052
,0000614
,0000048
,0000489
0.0000213
0.0000030
0.0000066
0.0000006
0.0000103
0.0000026
0.0000293
0.0000043
0.0000202
0.0000107
Subpart B - Copper Casting Subcategory
(a) Dust Collection Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
ka/kkq (lb/1000 lb) of Sand Handled
Copper
Lead
Zinc
0.000550
0.0000430
0.000438
0.000262
0.0000388
0.000180
947
-------
(b) Mold Cooling and Casting Quench Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
kg/kkq (lb/1000 Ib) of Metal Poured
Copper
Zinc
0.00302
0.00240
0.00144
0.000990
Subpart C - Ferrous Casting Subcategory
(a) Dust Collection
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
kq/kkq (lb/1000 Ib) of Sand Handled
Copper
Lead
Zinc
0.000374 *
0.0000292 !
0.000298
0.000178
0.0000263
0.000123
(b) Melting Furnace Scrubber
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Copper
Lead
Zinc
kg/kkq (lb/1000 Ib) of Metal Poured
0.00347
0.000271
0.00277
0.00165
0.000244
0.00114
948
-------
(c) Slag Quench Operations
Pollutant or
Pollutant Property
Copper
Lead
Zinc
Maximum for
Any One Day
Maximum for
Monthly Average
ka/kkq (lb/1000 lb) of.Metal Poured
0.000961
0.0000751
0.000766
0.000458
0.0000676
0.000315
(d) Casting Quench and Mold Cooling Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
kg/kkq (lb/1000 lb) of Metal Poured
Copper *
Lead1
Zinc1
0.000587
0,0000459
0.000468
0.000280
0.0000413
0.000193
These limitations would be applicable only when casting quench
and mold cooling wastewaters are treated with other ferrous
subcategory process wastewaters.
(e) Sand Washing Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Copper
Lead
Zinc
kq/kkq (lb/1000
0.00299
0.00234
0.00238
lb) of Sand Handled
0.00143
0.000210
0.000981
949
-------
Subpart D - Lead Casting
(a) Grid Casting Operations
Subcategory
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximun for
Monthly Average
Lead
kg/kkq (lb/1000 Ib) of Metal Poured
0.0000113 0.0000102
(b) Melting Furnace Scrubber Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Lead
kq/kkg (lb/1000 Ib) of Metal Poured
0.000154 0.000139
Subpart E - Magnesium Casting Subcategory
(a) Grinding Scrubber Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kq/kkq (lb/1000 Ib) of Metal Poured
0.00340 , 0.00140
950
-------
(b) Dust Collection Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kg/kkq (lb/1000 lb) of Sand Handled
0.0000468 0.0000193
Subpart F - Zinc Casting Subcategory
(a) Die Casting and Casting Quench Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
kq/kkq (lb/1000 lb) of Metal Poured
0.0000851 0.0000350
(b) Melting Furnace Scrubber Operations
Pollutant or
Pollutant. Property
Maximum for
Any One Day
Maximum for
Monthly Average
Zinc
Phenols (4AAP)
kq/kkq (lb/1000 lb) of Metal Poured
0.00161
0.0157
0.000661
0.00787
951
-------
952
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-------
-------
SECTION XI
BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY
The 1977 Amendments added Section 301(b)(2)(E) to the Act
establishing the "best conventional pollutant control technology"
(BCT) for discharges of conventional pollutants from existing
industrial point sources. Conventional pollutants are those
defined in "Section 304(a){4) [biochemical oxygen demanding
pollutants (BOD5J., total suspended solids (TSS), fecal coliform,
and pH], and any additional pollutants defined by the
Administrator as "conventional" (oil and grease, 44 FR 44501,
July 30, 1979).
BCT is not an additional limitation but replaces BAT for the
control of conventional pollutants. In addition to other factors
specified in Section 304(b)(4)(B), the Act requires that BCT
limitations be assessed in light of a two part "cost-
reasonableness" test. American Paper Institute v. EPA, 660 F.2d
954 (4th Cir. 1981). The first test compares the cost for
private industry to reduce its conventional pollutants with the
costs to publicly owned treatment works for similar levels of
reduction in their discharge of these pollutants. The second
test examines the cost-effectiveness of additional industrial
treatment beyond BPT. EPA must find that limitations are
"reasonable" under both tests before establishing them as BCT.
In no case may BCT be less stringent than BPT.
EPA published its methodology for carrying out the BCT analysis
on August 29, 1979 (44 F.R. 50732). In the case mentioned above,
the Court of Appeals ordered EPA to correct data errors
underlying EPA's calculation of the first test, and to apply the
second cost test. (EPA has argued that a second cost test was
not required).
EPA has determined that the BAT alternatives considered in this
category are capable of removing significant amounts of
conventional pollutants. On October 29, 1982, the Agency
proposed a revised BCT methodology. EPA is deferring proposing
BCT limitations for this category until the revised methodology
can be applied to the technologies available for the control of
conventional pollutants in this category.
965
-------
-------
SECTION XII
EFFLUENT QUALITY ATTAINABLE THROUGH THE APPLICATION
OF NEW SOURCE PERFORMANCE STANDARDS
INTRODUCTION
A new source is defined as any source the construction of which
is commenced after the publication of proposed regulations
prescribing new source performance standards. The basis for New
Source Performance Standards {NSPS) under Section 306 of the Act
is to be the best available demonstrated technology. New plants
have the opportunity to design the best and most efficient
manufacturing processes and wastewater treatment technologies.
Congress, therefore, directed EPA to consider the best
demonstrated processes and operating methods, in-plant control
measures, end-of-pipe treatment technologies, and other
alternatives that reduce pollution to the maximum extent
feasible, including, where practicable, no discharge of
pollutants to navigable waters.
Identification of NSPS
For the 14 process segments in which "no discharge of process
wastewater pollutants" is proposed at BPT, EPA did not develop
alternative treatment models for NSPS. BAT is equivalent to BPT
for these process segments and represents current, state-of-the-
art treatment facilities and practices. Therefore, no additional
treatment alternatives or practices have been considered by the
Agency for NSPS. For these 14 process segments the proposed NSPS
are equivalent to the proposed BAT limitations.
For the remaining 5 process segments EPA , considered alternative
NSPS treatment models that are equivalent to the BPT and the BAT
treatment alternatives. ,
Following is a summary of the NSPS model treatment alternatives
with references to the equivalent BPT and BAT alternatives:
Process
Alurn inum-Investment
Casting
Aluminum-Melting Furnace
Scrubber
NSPS
Alternative
NSPS No. 1
NSPS No. 2
NSPS No. 3
NSPS No. 1
NSPS No. 2
Equivalent
Reference Models
BPT
BPT and BAT No. 1
BPT and BAT No. 2
BPT
BPT and BAT No. 1
967
-------
NSPS No. 3
BPT- and BAT No. 2
Aluminum-Die Casting
Lead-Continuous
Strip Casting
NSPS
NSPS
NSPS
NSPS
NSPS
NSPS
NSPS
NO.
No.
No.
No.
No.
No.
No.
1
2
3
4
1
2
3
BPT
BPT and BAT No. 1
BPT and BAT No. 2
BPT and BAT No. 3
BPT
BPT and BAT No. 1
BPT and BAT No. 2
Zinc-Melting Furnace
Scrubber
NSPS No. 1
NSPS No. 2
NSPS No. 3
NSPS No. 4
BPT
BPT and BAT No. 1
BPT and BAT No. 2
BPT and BAT No. 3
Figures XII-1 through XII-17 depict the above NSPS alternative
treatment systems. Refer to Section IX for illustrations of the
model treatment systems for the remaining process segments.
i
Rationale for NSPS |
In those process segments in which the proposed BPT effluent
limitations require no discharge of process wastewater
pollutants, complete recycle clearly ; represents the best
demonstrated technology. ;
NSPS Effluent Levels
For those five process segments for which BPT and BAT treatment
models and alternatives were developed, the effluent levels
attainable by the NSPS treatment alternatives are identical to
those presented for the corresponding treatment models and
alternatives in Sections IX and X. As noted above, the NSPS
model treatment systems for the remaining process segments
provide a treatment approach similar to that of the BPT and BAT
model treatment systems, i.e., no discharge of process wastewater
pollutants to navigable waters.
Selection of an NSPS Alternative
In the 15 process segments in which the proposed BAT levels of
treatment achieve no discharge of process wastewater pollutants
to navigable waters, the proposed NSPS are equal to the proposed
BAT limitations. '
!
In two process segments (aluminum investment casting and aluminum
melting furnace scrubber), the selected NSPS alternatives are
968
-------
identical to the BPT model treatment systems, i.e., NSPS No. 1.
In the investment casting process segment complete recycle is
neither demonstrated nor readily transferred. Likewise, complete
recycle is not demonstrated in the aluminum melting furnace
scrubber process segment.
In the aluminum die casting segment and the lead continuous strip
casting process segments, the proposed NSPS are based upon the
demonstrated treatment technologies of the NSPS Alternative No. 2
treatment systems. While the Agency considered treatment
alternatives beyond the NSPS Alternative No. 2 level of
treatment, the Agency concluded that the other alternatives are
not demonstrated. The selected alternatives are equivalent to
the selected or preferred BAT model treatment systems. Details
pertaining to these treatment systems, and the resulting limits
and standards, were previously reviewed in Sections IX and X.
Following are the proposed NSPS for the three process segments
with discharge standards other than zero discharge:
PROPOSED NSPS
Aluminum-Investment Casting Process
Pollutant or
Pollutant Property
Maximum for
Any One Day
(kq/kkq)
Maximum for
Monthly Average
(kq/kkq)
TSS
Oil and Grease
pH
1.103 0.538
0.538 0.323
Within the range of 7.5 to 10
969
-------
PROPOSED NSPS ',
Aluminum Melting Furnace Scrubber Pro'cess
Pollutant or
Pollutant Property
Maximum for
Any One Day
(kq/kkq)
Maximum for
Monthly Average
(kq/kkq)
TSS
Oil and Grease
PH
0.0166 0.00809
0.00809 ! 0.00486
Within the range of 7.5 to 10
PROPOSED NSPS f
Aluminum-Die Casting Process
Pollutant or
Pollutant Property
Maximum for
Any One Day
(kq/kkq)
Maximum for
Monthly Average
(kq/kkq)
Acenaphthene
2,4,6-trichlorophenol
Parachlorometacresol
Chloroform
Phenol
Butyl benzyl phthalate
Chrysene
Tetrachloroethylene
Lead
Zinc
Phenols (4AAP)
TSS
Oil and Grease
PH
i
0.0000092
0.0000305
0.0000281
0.0000668
0.0000063
0.000104
0.0000019
0.0000261
0.0000242
0.000247
0.000107
0.00363
0.00242
Within the range of
0.0000046
0.0000152
0.0000140
0.0000334
0.0000031
0.0000518
0.0000010
0.0000131
0.0000218
0.000102
0.0000537
0.00266
0.00242
7.5 to 10
970
-------
PROPOSED NSPS
Lead-Continuous Strip Casting Process
Pollutant or
Pollutant Property
Maximum for
Any One Day
(kq/kkq)
Maximum for
Monthly Average
(kq/kkq)
Lead
TSS
Oil and Grease
0.0000227 0.0000204
0.00340 0.00250
0.00227 0.00227
Within the range of 7.5 to 10
971
-------
972
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SECTION XIII
PRETREATMENT STANDARDS FOR DISCHARGES
TO PUBLICLY OWNED TREATMENT WORKS
Introduction
Section 307(Ib) of the Act requires EPA to promulgate pretreatment
standards for existing sources (PSES) which must be achieved
within three years of promulgation. PSES are designed to prevent
the pass through of toxic pollutants at POTW systems. The
legislative history of the 1977 Clean Water Act indicates that
pretreatment standards are to be technology-based, i.e.,
analogous to the best available technology for the removal of
toxic pollutants.
Section 307(e) of the Act requires EPA to promulgate pretreatment
standards for new sources (PSNS) at the same time that it
promulgates NSPS. New indirect dischargers, like new direct
dischargers, have the opportunity to incorporate the best
available demonstrated technologies including process changes,
in-plant controls, and end-of-pipe treatment technologies, and to
use plant site selection to facilitate the installation of
adequate treatment capabilities.
General Pretreatment Standards
For detailed information on Pretreatment Standards refer to 46 FR
9404 et seq, "General Pretreatment Regulations for Existing and
New Sources of Pollution," (January 28, 1981). See also 47 FR
4518 (February 1, 1982). In particular, 40 CFR Part 403
describes national standards (prohibited and categorical
standards), revision of categorical standards through removal
allowances, and POTW pretreatment programs.
In developing the proposed pretreatment standards for foundry
operations, the Agency gave primary consideration to the
objectives and requirements of the General Pretreatment
Regulations. The Agency determined that uncontrolled discharges
of certain metal molding and casting operations' wastewaters to
POTWs would result in the pass through of toxic pollutants.
Categorical Pretreatment Standards
POTWs are usually not designed to treat the toxic pollutants
(primarily the toxic metals) present in foundry process
wastewaters. Instead, POTWs are typically designed to treat
989
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biochemical oxygen demand (BOD), total suspended solids (TSS),
fecal coliform bacteria, and pH.
Before proposing pretreatment standards, the Agency examined
whether the pollutants discharged by the industry pass through
the POTW or interfere with the POTW operation or sludge disposal
practices. In determining whether pollutants pass through a
POTW, the Agency compares the percentage of a pollutant removed
by a POTW with the percentage removed by direct dischargers
applying BAT. A pollutant is deemed to pass through the POTW
when the average percentage removed nationwide by a well-operated
POTW meeting secondary treatment requirements is less then the
percentage removed by direct dischargers complying with BAT
effluent limitations for that pollutant. ;
!
This approach to the definition of pass through satisfies two
competing objectives set by Congress: that standards for
indirect dischargers be equivalent to standards for direct
dischargers, while, the treatment capability and performance of
the POTW be recognized and taken into account in regulating the
discharge of pollutants from indirect dischargers. Rather than
comparing the mass or concentration of pollutants discharged by
the POTW with the mass or concentration discharged by a direct
discharger, the Agency compared the percentage of the pollutants
removed in treatment. The Agency takes this approach because a
comparison of the mass or concentration of pollutants in a POTW
effluent with the mass or concentration in a direct discharger's
effluent would not take into account .the mass of pollutants
discharged to the POTW from non-industrial sources nor the
dilution resulting from the addition of large amounts of non-
industrial wastewater.
i
In the foundry category the Agency has concluded that the toxic
metals and toxic organics that would be regulated under these
proposed standards would pass through the POTW.
The average percentage of toxic metals removed by POTWs
nationwide ranges from 19 to 65 percent (as seen below).
National Removal Credit Efficiencies
Cadmium
Chromium
Copper
Lead
Nickel
Silver
Zinc
38%
65%
58%
48%
19%
66%
65%
990
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Total Regulated Metals
Cyanide
62%
52%
EPA developed the "national removal credits" on the basis of its
"Fate of Priority Pollutants in POTWs" report (EPA 440/1-82/303).
The Agency estimates that the percentage of toxic metals that can
be removed by a direct discharger applying BAT is expected to be
abov"e 70 percent. Accordingly, these pollutants pass through
POTWs. In addition, since toxic metals are not degraded in the
POTW (they either pass through or are removed in the sludge),
their presence in the POTW sludge may limit a POTWs chosen
sludge disposal method.
In addition to toxic metals, the POTW study collected limited
data on toxic organic pollutants. Removals of these pollutants,
some of which are also discharged by foundries, are in the range
of 60 to 95 percent. Complete recycle of process wastewater
removes all toxic organic pollutants from discharge. For the one
process segment, aluminum die casting, with a PSES discharge
allowance for toxic organic pollutants, the toxic organic
pollutant removals are estimated to be 95 percent. The Agency
has concluded that the toxic organic pollutants regulated under
these proposed standards would pass through a POTW.
The toxic pollutant removal provided by POTWs is incidental to
the POTWs main function of conventional pollutant treatment.
POTWs have, historically, accepted quantities of many pollutants
which are well above levels which POTWs have the capacity to
treat adequately.
Due to the presence of toxic pollutants in wastewaters from
foundry operations, pretreatment must be provided to ensure that
these pollutants do not pass through the POTW.
Pretreatment standards for total suspended solids, oil and
grease, and pH are not proposed because these pollutants can be
effectively treated at POTWs.
The following discussions identify the rationale for the model
treatment technologies, the expected levels of pollutant removal,
and, finally, the selection of pretreatment models upon which the
categorical proposed PSES and PSNS are based.
Identification of. Pretreatment
For the 14 process segments in which "no discharge of process
wastewater pollutants" is proposed at BPT, EPA did not develop
alternative treatment models for PSES and PSNS. BAT is
'991
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equivalent to BPT for these process segments. The proposed PSES
are technology-based and analogous to ; the proposed BAT
limitations for toxic pollutants .in these 14 process segments.
For the same 14 process segments, the proposed NSPS are "no
discharge of process wastewater pollutants." In these segments
the Agency is proposing PSNS equivalent to NSPS.
By eliminating the discharge to a POTW, complete recycle provides
the maximum level of toxic pollutant control. In addition,
expenditures for effluent monitoring and for POTW user fees are
reduced or eliminated. The model treatment systems for these
process, segments are illustrated in Sections IX and X. For the
remaining 5 process segments EPA considered1 alternative PSES and
PSNS treatment models that are equivalent to the BAT and NSPS
treatment alternatives. i
Following is a summary of the treatment
remaining five process segments.
model bases for the
Process
Aluminum Investment
Casting
PSES/PSNS
Alternative
No. 1
No. 2
No. 3
Aluminum Melting Furnace No. 1
Scrubber No. 2
No. 3
Aluminum Die Casting
Lead Continuous
Strip Casting
Zinc Melting Furnace
Scrubber
No. 1
No. 2
No. 3
No. 4
No. 1
No. 2
No. 3
No. 1
No. 2
No. 3
No. 4
Reference Models
BPT
BPT and BAT No. 1
BPT and BAT No. 2
BPT
BPT and BAT No. 1
BPT AND BAT No:2
BPT
BPT and BAT No. 1
BPT and BAT No. 2
BPT and BAT No. 3
""BPT" " ' "'
BPT and BAT No. 1
BPT and BAT No. 2
BPT
BPT and BAT No. 1
BPT and BAT No. 2
BPT and BAT No. 3
Figures XIII-1 through XIII-17 illustrate the above PSES and PSNS
treatment models.
992
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Selection of -PSES and PSNS
The Agency found no POTW dischargers in either segment of the
magnesium casting subcategory. Therefore, the Agency is not
proposing PSES for the magnesium subcategory grinding scrubber or
dust collection process segments. The proposed PSNS in these two
segments are equivalent to the proposed NSPS.
The following discussions address each of the process segments
for which pretreatment alternatives were developed.
Aluminum-Investment Casting
The Agency is not proposing PSES or PSNS because at the levels of
total suspended solids and oil and grease discharged from this
process these pollutants are considered compatible with treatment
by POTWs. Furthermore, the toxic metals present in the raw
wastewaters of this process segment are below the treatability
levels of precipitation and sedimentation technologies.
Aluminum - Melting Furnace Scrubber
The Agency is not proposing PSES or PSNS because at the levels of
total suspended solids and oil and grease discharged from this
process these pollutants are considered compatible with treatment
by POTWs. Furthermore, the toxic metals present in the raw
wastewaters of this process segment are below the treatability
levels of precipitation and sedimentation technologies.
Aluminum - Die Casting
In this process segment the Agency is proposing PSES equivalent
to the proposed BAT limitations and PSNS equivalent to the
proposed NSPS. The technologies used as the bases for the
proposed PSES and PSNS are identical and represent the best
demonstrated technology in this segment. Refer to Sections X and
XII for details on the selection of the treatment alternative,
the selection of pollutants to be regulated, and the development
of effluent limitations and standards. The proposed PSES would
result in the removal of 59.4 kg per year of toxic pollutants.
Following are the proposed
casting process segment.
PSES and PSNS for the aluminum die
993
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PROPOSED PSES AND PSNS
Aluminum-Die Casting Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
(kq/kkq)
Maximum for
Monthly Average
(kg/kkg)
Acenaphthene
2, 4, 6-trichlorophenol
Parachlorometacresol
Chloroform
Phenol
Butyl benzyl phthalate
Chrysene
Tetrachloroethylene
Lead
Zinc
Phenols (4AAP)
0.0000092
0.0000305
0.0000281
0.0000668
0.0000063
0.000104
0.0000019
0.0000261
0.0000242
0.000247
0.000107
0.0000046
0.0000152
0.0000140
0.0000334
0.0000031
0.0000518
0.0000010
0.0000131
0.0000218
0.000102
0.0000537
Lead - Continuous Strip Casting
In the lead continuous strip casting process segment the Agency
is proposing PSES based upon sedimentation, precipitation, and
filtration technologies (BAT Alternative 1). ' These technologies
are demonstrated by four of the five continuous strip casting
plants. The proposed PSES would result in the removal of 6.9 kg
per year of toxic metals. The Agency is proposing PSNS
equivalent to PSES. Refer to Sections X and XII for additional
details on the selection of the treatment alternative, the
selection of a regulated pollutant, and the development of
effluent standards.
PROPOSED PSES AND PSNS ' _
Lead Continuous Strip Casting Operations
Pollutant or
Pollutant Property
Maximum for
Any One Day
(kq/kkq)
Maximum for
Monthly Average
(kg/kkg)
Lead
0.0000227
0.0000204
994
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Zinc - Melting Furnace Scrubber
In this process segment the Agency is proposing PSES equivalent
to the proposed BAT limitations and PSNS equivalent to the
proposed NSPS. The technologies used as the bases for the
proposed PSES and PSNS are identical and represent the best
demonstrated technology in this segment. Refer to Sections X and
XII for details on the selection of the treatment alternative.
The proposed PSES and PSNS are no discharge of process wastewater
pollutants to a POTW.
POTW Removal Rate Comparison
The toxic metal pollutant removal rates of the selected
pretreatment alternatives for the two process segments which
incorporate a discharge are compared to the POTW removal rates
for these pollutants:
Actual POTW
Aluminum Subcategory-
Die Casting Process
Lead Subcategory - Continuous
Strip Casting Process
Lead
48%
99%
89%
Zinc
65%
>99%
995
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As shown above the selected alternatives will remove these toxic
metals (i.e., prevent the pass through of toxic metals at POTWs)
to a significantly greater degree than would occur if these
wastewaters were discharged untreated to POTWs. The
achievability of the proposed standards is reviewed in Sections
IX, X, and XII.
ANALYSIS OF PSES DISCHARGE OPTIONS
As with the BPT level of treatment, discharge alternatives were
also considered for the PSES level of treatment. These discharge
alternatives, incorporating 90% and 50% recycle, are similar to
those addressed in the BPT discussion (see Section IX) . The
assumptions made and the evaluation processes followed are
similar to the assumptions and review processes of the BPT
discharge alternative analysis. '-,
The 90% and 50% recycle options considered as possible bases for
PSES were rejected for the reasons set forth in Section. IX.
Complete recycle is economically achievable and will remove
substantial quantities of toxic pollutants. A number of process
segments would discharge toxic organic pollutants (principally
phenolic compounds) if complete recycle were not the basis for
PSES. These pollutants would appear in the range of 0.5 mg/1 to
30.7 mg/1 in the discharges. Neither the i90% nor the 50% recycle
option was based upon technologies that would treat toxic organic
pollutants. If a discharge option were selected for PSES and
these pollutants required treatment, the total cost of these
options would far exceed the cost of complete recycle.
The alternative PSES and PSNS which would be established if
either discharge alternative were selected are equivalent to the
alternative BAT limitations presented in Tables X-2 and X-3.
996
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SECTION XIV
ACKNOWLEDGEMENTS
The Environmental Protection Agency was aided in the preparation
of this Development Document by the Cyrus Wm. Rice Group of NUS
Corporation. Rice's effort was managed by Mr. Thomas J. Centi.
Mr. David E. Soltis and Mr. Samuel A. Young directed the
engineering activities and were assisted by Ms. Debra
M. Wroblewski, Ms. Joan 0. Knapp, Mr. Joseph J. Tarantino, and
Mr J. Steven Paquette. Field and sampling programs were
conducted under the leadership of Mr. David E. Soltis and Mr.
Samuel A. Young. Laboratory and analytical services were
conducted under the guidance of Miss C. Ellen Gonter and
Mrs. Linda Dean. The drawings contained within were P^P3.1^ by
the RICE drafting personnel Mr. William B. Johnson,
Mr. Keith Christner, and Mr. Richard J. Deluca, under the
supervision of Mr. Albert M. Finke. The work associated with
calculations of raw waste loads and effluent loads is attributed
to Mr David E. Soltis, Ms. Debra M. Wroblewski, Ms. Joan Knapp,
and Mr. Joseph J. Tarantino. The cost estimates for treatment
models were prepared by Mr. Albert M. Finke. Computer services
were provided by Mr. J. Steven Paguette, Mr. Joseph J. Tarantino,
Ms. Joan 0. Knapp, and Mr. Henry K. Hess.
Acknowledgement and appreciation are given to Ms. Kaye Storey,
Ms. Carol Swann, Ms. Pearl Smith and Ms. Glenda Nesby of the
Agency's word processing staff for their tireless and dedicated
effort in this document. Acknowledgement and appreciation are
also given to Ms. Ellen Siegler of the Agency's Office of General
Counsel, Mr. John Kukulka of the Agency's Economic Analysis
Branch/and Mr. Mahesh Podar of the Agency's Office of Policy and
Resource Management. The administrative assistance provided by
Mrs. Irena Wagner of the C.W. Rice Group of NUS Corporation is
also greatly appreciated.
Finally, the excellent cooperation of the many companies who
participated in the survey and contributed pertinent data is
gratefully appreciated. Special thanks is also given to the Cast
Metals Federation and the American Foundrymen s Society.
1015
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SECTION XV
REFERENCES
1. Bader, A. J., "Waste Treatment for an Automated Gray and
Nodular Iron Foundry", Proceedings of the Industrial Waste
Conference, 22nd, Purdue University, pp. 468-476 (1967).
2. ' "Chrysler's Winfield Foundry Solves Pollution Problem",
Foundry, 97, pp. 162, 167-169 (September, 1969).
3. "Cupola Emission Control", Engles and Weber (1967).
4. "Cupola Pollution Control at Unicast", Foundry, 98, pp, 240,
242 (April, 1970).
5. Deacon, J. S.M "In Defense of the Wet Cap", Modern Casting,
pp. 48-49 (September, 1973).
6. "Emissions Control System is Based on Impingement", Foundry,
101, N. 9, pp. 108-110 (September, 1973).
7. U.S. Environmental Protection Agency, Development Document
for Effluent Limitations Guidelines and Standards for the
Iron and" Steel Manufacturing Point Source Category - Final,
EPA 440/182/024, Washington, D.C., May 1982.
8. Foundry, "1973 Outlook" (January, 1973).
9. "Foundries Look at the Future", Foundry (October, 1972).
10. "Inventory of Foundry Equipment", Foundry (May, 1968).
11. "Iron Casting Handbook", Gray and Ductile Iron Foundries
Society,, Inc., 1971, Cleveland, Ohio.
12. Manual Standard Industrial Classification (1967).
13. "Metal Casting Industry Census Guide", Foundry (August,
1972).
14. Miske, Jack C., "Environment Control at Dayton Foundry",
Foundry, 98, pp. 68-69 (May, 1970).
15. Settling Basins Clean GM Foundry Water", Foundry, 97, p. 146
(February, 1969).
1017
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16. U. S. Department of Commerce, "Iron and Steel Foundries and
Steel Ingot Producers", Current Industrial Reports, pp. 1-18
(1971). ;
17. U. S. Department H.E.W., Public Health Service Publication,
t99-AP-40.
18. Wagner, A. J. , "Grede's Wichita MidwestDivision Honored
for Top Environmental Control Job", Modern Casting, 58, N.6,
pp. 40-43 (December, 1970). ;
19. "Water Pollution From Foundry Wastes", American Foundrymen's
Society (1967).
i
20. Waters, 0. B., "Total Water Recycling for Sand System
Scrubbers", Modern Casting, pp. 31-32 (July, 1973).
21. U.S. Industrial Outlook, 1977, U.S. Department of Commerce.
22. Building Construction Cost Data, 1978 Edition.
23. "Richardson Rapid System", 1978-79 Edition, by Richardson
Engineering Services, Inc.
24. U.S. Department of Commerce, Survey of Manufacturers, 1970.
25. Wiese-Nielsen, K. Dr., "High Pressure Water Jets Remove
Investment Casting Shells", Foundry M/T, September, 1977.
26. "Sand Reclamation - A Status Report of Committee 80-S",
Modern Casting, Manual 79, pp. 60.. j
27. David Kanicki, "Water at Neenah Foundry", Modern Casting,
July 1978, pp. 44.
28. Eckenfelder, W. Wesley, Industrial Water Pollution Control.
29. Menerow, Nelson, L., Industrial Water Pollution.
30. Parsons, William A. Dr., Chemical Treatment of Sewage and
Industrial Wastes.
31. Kearney, A. T. and Company, Inc., "Study of Economic Impacts
of Pollution Control on the Iron Foundry Industry", 1971.
1018
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SECTION XVI
GLOSSARY
Acrylic Resins - Synthetic resins used as sand binders for
coremaking. These resins are formed by the polymerization of
acrylic acid or one of its derivatives with benzoyl peroxide or a
similar catalyst. The most frequently used starting materials
for these resins include acrylic acid, methacrylic acid, or
acrylonitrile. Since exposure of these binder materials to hot
metal temperatures could cause breakdown of these binders,
cyanide might be generated.
Agglomerate. The collecting of small particles together into a
larger mass.
Air Setting Binders - Sand binders which harden by exposure to
air. Sodium silicate, Portland cement, and oxychloride are the
primary constituents of such binders.
Magnesia used in the blending of oxychloride can contain small
amounts of impurities such as calcium oxide, calcium hydroxide or
calcium silicate which increase the volume change during the
setting process, thus decreasing mold strength and durability.
To eliminate this lime effect, 10 percent of finely divided
metallic copper is added to the mixture.
Alkyd Resin Binders - Cold set resins used in the forming of
cores. This type of binder is referred to as a three component
system using alkyd-isocyanate, cobalt naphthenate, and diphenyl
methane di-isocyanate. Cobalt naphthenate is the drier and
diphenyl methane di-isocyanate is the catalyst. Exposure of
these binders to hot metal temperatures can cause the breakdown
of these binder materials, and the resulting degradation products
might include naphthalenes, phenols, and cyanides, in some
separate or combined form.
Alloying Materials and Additives - The following is a list of
materials known to be used in foundry operations.
1019
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Aluminum
Beryllium
Bismuth
Boron
Cadmium
Calcium
Carbon
Cerium
Chloride
Chromium
Cobalt
Columbium
Copper
Hydrogen
Iron
Lead
Lithium
Magnesium
Manganese
Molybdenum
Nickel
Nitrogen
Oxygen
Phosphorus
Potassium
Selenium
Silicon
Sulfur
Tantalum
Tin
Titanium
Tungsten
Vanadium
Zinc
Zirconium
Baghouse. An independent structure or;building that contains
fabric bags to collect clusts. Usually incorporates fans and dust
conveying equipment.
Binder. Any material used to help sand grains to stick together.
Borides - A class of boron containing; compounds, primarily
calcium boride, used as a constituent in refractory materials.
Metallic impurities that often accompany the use of these
materials include titanium, zirconium, hafnium, vanadium,
niobium, tantalum, chromium, molybdenum, tungsten, thorium, and
uranium.
Bulk Bed Washer. A wet type dust collector consisting of a bed
of lightweight spheres through which the dust laden air must pass
while being sprayed by water or liquor.
Catalysts - Materials used to set binder materials used in core
and mold formation. Primary set catalysts used are phosphoric
acid and toluenesulfonic acid. Exposure of residual catalyst
materials in the mold to hot metal temperatures could cause
chemical breakdown of these materials with the possible
generation of free toluene.
Charcoal - A product of the destructive distillation of wood.
Used for heat and as a source of carbon in the foundry industry.
Because of the nature of the destructive distillation process,
charcoal may contain residuals of toxic pollutants such as
phenol, benzene, toluene, naphthalene, and nitrosamines.
Charge. A minimum combination of the various materials required
to produce a hot metal of proper specifications.
Chrome Sand - (Chrome-Iron Ore) - A dark material containing dark
brown streaks with submetallic to metallic;luster. Usually found
as grains disseminated in perioditite rocks. Used in the
preparation of molds.
1020
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Chromite Flour - (See Chrome Sand above) - Chrome sand ground to
200 mesh or finer, can be used as a filler material for mold
coatings for steel castings.
Clarification. The process of removing undissolved materials
from a liquid', specifically by sedimentation.
Classifier. A device that separates particles from a fluid
streamby size. Stream velocity is gradually reduced, and the
larger sized particles drop out when the stream velocity can no
longer carry them.
Cleaning Agents and Deqreasers
polychloroethylene, trichloroethylene.
Ethylene dichloride,
Coagulant. A compound which, when added to a wastewater stream,
enhances wastewater settleability. The coagulant aids in the
binding and agglomeration of the particles suspended in the
wastewater.
Coatings - Corrosion Resistant - Generally alkyd or epoxy resins.
See Alkyd Resin Binders and Epoxy Resins. Applied to metal molds
to prevent surface corrosion.
Coke-Foundry - The residue from the destructive distillation of
coal. A primary ingredient in the making of cast iron in the
cupola. Because of the nature of the destructive distillation
process and impurities in the coal, the coke may contain
residuals of toxic pollutants such as phenol, benzene, toluene,
naphthalene and nitrosamines.
Coke-Petroleum - Formed by the destructive distillation of
petroleum. Like foundry coke, petroleum coke can also be used
for making cast iron in the cupola.
Coke-Pitch - Formed by the destructive distillation of petroleum
pitch. Used as a binder in the sand molding process.
Coolants - Water, oil and air. Their use is determined by the
extent and rate of cooling desired.
Cope. The top half of a two-piece sand mold.
Core. An extra-firm shape of sand used to obtain a hollow
secTion in a casting by placing it in a mold cavity to give
interior shape to a casting.
Core Binders - Bonding and holding materials used in the
formation of sand cores. The three general types consist of
1021
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those that harden at room temperature, those that require baking,
and the natural clays. Binders that harden at room temperature
include sodium silicate, Portland cement, and chemical cements
such as oxychloride. Binders that require baking include the
resins, resin oils, pitch, molasses, cereals, sulfite liquor, and
proteins. Fireclay and bentonite are the clay binders.
I
Core Binder Acceleratros - Used in conjunction with Furan resins
to cause hardening of the resin-sand mixture at room temperature.
The most commonly used accelerator is phosphoric acid.
Core and Mold Washes - A mixture of various materials, primarily
graphite, used to obtain a better finish on castings, including
smoother surfaces, less scabbing and buckling, and less metal
penetration. The filler material for washes should be refractory
type composed of silica flour, zircon flour or chromite flour.
Core Oils - Used in oil-sand cores as a parting agent to prevent
the core material from sticking to the cast metal. Core oils are
generally classified as mineral oils (refined petroleum oils) and
are available as proprietary mixtures or can be ordered to
specification. Typical core oils have specific gravities of 0.93
to 0.965 and contain a minimum of 70 percent nonvolatiles at
177°C (350°F). I
Crucible. A highly refractory vessel used to melt metals.
r
Cupola. A verticle shaft furnace consisting of a cylindrical
steel shell lined with refractories and equipped with air inlets
at the base and an opening for charging with fuel and melting
stock near the top. Molten metal runs to the bottom.
Pie Coatings - Oil containing lubricants or parting compounds
such as carbon tetrachloride, cyclohexane,! methylene chloride,
xylene and hexamethylenetetramine. The coatings used to prevent
castings from adhering to the die and to provide a casting with a
better finish. A correctly chosen lubricant will allow metal to
flow into cavities that otherwise cannot be filled.
Drag. The lower half of a two-piece sand mold.
Electrode. Long cylindrical rods made of carbon or graphite and
used to conduct electricity into a charge of metal.
Epoxy Resins - Two component resins used to provide corrosion
resistant coatings for metallic molds or castings. These
materials are synthetic resins obtained by the condensation or
polymerization of phenol, acetone, and epichlorohydrin
(chloropropylene oxide). Alkyds, acrylates, methacrylates and
1022
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as indene, coumarone and
and synthetic rubbers all
Polyamine and amine based
agents. Because of the
are exposed, and because of
used to produce many of the
pollutants such as zinc,
naphthalene, and possibly
allyIs, hydrocarbon polymers such
styrene, silicon resins, and natural
can be applied as additives or bases
compounds are normally used as curing
temperatures to which these materials
the types of materials that are
components of these materials, toxic
nickel, phenol, benzene, toluene,
nitrosamines could be generated.
Filter Cake. That layer of dewatered sludge removed from the
surface~of~a filter. This filter is used to reduce the volume of
sludge generated as a result of the waste treatment process.
Flask. A rectangular frame open at top and bottom used to' retain
molding sand around a pattern.
Flocculation. The process in which particles agglomerate,
resulting in an increase in particle size and settleability.
Flux. A substance used to promote the melting or purification of
a metal in a furnace.
Furan Resins - A heterocyclic ring compound formed from diene and
cyclic vinyl ether. Its main use is as a cold set resin in
conjunction with acid accelerators such as phosphoric or toluene
sulfonic acid for making core sand mixtures that harden at room
temperature. Toluene could be formed during thermal degradation
of the resins during metal pouring.
Furfuryl Alcohol - A synthetic resin used to formulate core
binders. The amount of furfuryl alcohol used depends on the
desired core strength. One method of formulating furfuryl
alcohol is by batch hydrogenation of furfuryl at elevated
temperature and pressure with a copper chromite catalyst.
Furnace Charge - Scrap - Various toxic pollutant metals may be
present in the raw materials charged in the melting furnace.
These pollutants originate from various sources - iron ore, pigs,
steel or case scrap, automotive scrap, and ferroalloys. These
pollutants may be antimony, arsenic, chromium, copper, lead,
titanium, and zinc.
Gate. An entry passage for molten metal into a mold.
Gilsonite - A material used primarily for sand binders. It is
one of the purest natural bitumens (99.9 percent) and is found in
lead mines. Lead may be present as an impurity in Gilsonite.
1023
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Gypsum Cement - A group of cements consisting primarily of
calcium sulfate and produced by the complete dehydration of
gypsum. It usually contains additives such as aluminum sulfate
or potassium carbonate. It is used in sand binder formulation.
Head. A large reservoir of molten metal incorporated into a mold
to supply hot metal to a shrinking portion of a casting during
its cooling stage.
Heat Treat. To adjust or alter a metal property through heat.
Hydraulic Cyclone. A fluid classifying device that separated
heavier particles from a slurry.
Impingement.
or baffle.
The striking of air or gasborne particles on a wall
Impregnating Compounds - Materials of low viscosity and surface
tension used primarily for the sealing of castings. Polyester
resins and sodium silicate are the two types of materials used.
Phthalic anhydride and diallyl phthalate are used in the
formulation of the polyester resins.
Induction Furnace. A crucible surrounded by coils carrying
alternating electric current. The current induces magnetic
forces into the metal charged into the crucible. These forces
cause the metal to heat.
I
Investment Mold Materials - A broad range of waxes and resins
including vegetable wax, mineral wax, synthetic wax, petroleum
wax, insect wax, rosin, terpene resins, coal tar resins,
chlorinated elastomer resins, and polyethylene resins used in the
manufacture and use of investment molds. The presence of coal
tar resins in investment mold materials might indicate the
possible presence of toxic pollutants such as phenol, benzene,
toluene, naphthalene, and nitrosamines as residues in the resins
or as possible products of degradation of these resins when
subjected to heat.
i
Ladle. A vessel used to hold or pour molten metal.
Lignin Binders - Additives incorporated into resin-sand mixtures
to improve surface finish and to eliminate thermal cracking
during pouring. Lignin is a major polymeric component of ( woody
tissue composed of repeating phenyl propane units. It generally
amounts to 20-30 percent of the dry weight of wood. Phenol might
be generated during thermal degradation of! lignin binders during
metal pouring.
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Lubricants - Calcium stearate, zinc stearate and carnauba wax are
lubricating agents added to resin sand mixtures to permit the
easy release of molds from patterns.
Mica - A class of silicates with widely varying composition used
in the refractory making process. They are essentially silicates
of aluminum but are sometimes partially replaced by iron,
chromium and an alkali such as potassium, sodium or lithium.
Mold. A form made of sand, metal, or refractory material, which
contains the cavity into which molten metal is poured to produce
a casting.
MOLDING
COgMolding. The C02 (carbon dioxide) molding processes uses
sodium "silicate binders to replace the clay binders used in
sand molds and cores. In the CO2 process, a low strength
mold or core is made with a mixture of sodium silicate
(3-4%) and sand. Carbon dioxide gas is passed through the
sand, causing the sodium silicate to develop a dry
compressive strength greater than 200 psi. Ready-to-use
cores and complete molds can be made quickly, with no baking
or drying needed. The high strength developed by the C02
process enables molds to be made and poured without back-up
flasks or jackets.
No-Bake Molds. The process is of fairly recent (15 years)
origin. The sand coating consists of a binder and catalyst,
their interaction results in a molded sand with high green
strength (over 200 psi). The name of the process derives
from the fact that the mold requires no baking. The amount
of sand used, and the general form of the molds are similar
to green sand operations; however, the high strength permits
flask removal and mold pouring without a jacket. The
castings poured using this process have good dimensional
accuracy and excellent finish.
Permanent Mold Casting. A metal mold consisting of two or
more metal parts is used repeatedly for the production of
many castings of the same form. The molten metal enters the
mold by gravity. Permanent mold casting is particularly
suitable for high-volume production of small, simple
castings that have a uniform wall thickness and no undercuts
or intricate internal coring.
Plaster Mold Casting. Plaster mold casting is a specialized
casting process used to produce nonferrous castings that
have greater dimensional accuracy, smoother surfaces and
1025
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more-finely reproduced details than
sand molds or permanent molds.
can be obtained with
Shell Molding. Shell molding is a process in which a mold
is formed from a mixture of sand and a heat-setting resin
binder. The sand resin mixture is placed in a heated metal
pattern in which the heat causes the binder to set. As the
sand grains adhere to each other, a sturdy shell, which
becomes one half of the mold, is formed. The halves are
placed together with cores located properly, clamped and
adequately backed up, and then the mold is poured. This
process produces castings with good surface finish and good
dimensional accuracy while using smaller amounts of molding
sand.
No Bake Binders - Furan resins and alkyd-isocyanate compounds are
the two predominant no bake binders. Furan resins, as previously
mentioned, are cyclic compounds which use phosphoric acid or
toluenesulfonic acid as the setting agents. Alkyd-isocyanate
binders have fewer limitations in use than furan resins, but the
handling of cobalt naphthenate does present problems.
Pattern. A form of wood, metal, or other material around which
molding material is placed to make a mold for casting metals.
Phenolic Resins - Phenol formaldehyde resins - A group of varied
and versatile synthetic resins. They are made by reacting almost
any phenolic and an aldehyde. In some cases, hexamethylene-
tetramine is added to increase the aldehyde content. The resins
formed are classified as one and two step resins depending on how
they are formed in the reaction kettle. Both types of materials
are used separately or in combination in the blending of
commercial molding materials. Due to the thermal degradation of
phenolic resins that may occur during metal pouring, phenol and
formaldehyde may be generated.
Pitch Binders - Thermosetting binders used ,in coremaking. Baking
of the sand-binder mixture is required for i evaporation-oxidation
and polymerization to take place.
Polymeric Flocculant (Polyelectrolvte). High molecular weight
compounds which, due to their charges, aid in particle binding
and agglomeration.
Quenching. A process of inducing rapid cooling from an elevated
temperature.
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Quenching Oil - Medium to heavy grade mineral oils used in the
cooling of metal. Standard weight or grade of oil would be
similar to standard SAE 60.
Recycle - The practice of returning, in whole or in part, treated
or untreated process wastewaters to the process.
Recuperator. A steel or refractory chamber used to reclaim
from waste gases.
heat
Riser Compounds - Extra strength binders used to reduce the
extent of riser erosion. Such materials generally contain
lignin, furfuryl alcohol and phosphoric acid.
Rosins, Natural - (Gum rosin, colophony, pine resin, common
rosin) - A resin obtained as a residue after the distillation of
turpentine oil from crude turpentine. Rosin is primarily an
isomeric form of the anhydride of abietic acid. It is one of the
more common binders in the foundry industry.
Sand Flowability Additives - A mixture of sand, dicalcium
silicate, water and wetting agents. This combination is based on
a process of Russian origin which achieves a higher degree of
flowability than either the conventional sand mix or those with
organic additives.
Scrap. Usually refers to miscellaneous metal used in a charge to
make new metal.
Sand Binders - Binder .materials are the same as those used in
core making. The percentage of binder may vary in core and molds
depending on sand strength required, extent of mold distortion
from hot metal and the metal surface finish required.
Seacoal - Ground bituminous coal used to help control the thermal
expansion of the mold and to control the composition of the mold
cavity gas during pouring.
Shot Blast. A casting cleaning process employing a metal
abrasive (grit or shot)propelled by centrifugal or air force.
Shakeout. The operation of removing castings from the mold. A
mechanical unit for separating the mold material from the
solidified casting.
Slag. A product resulting from the action of a flux on the
oxidized non-metallic constituents of molten metals.
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Slag Quench. A process of rapidly cooling:mblten slagto a solid
material. Usually performed in a water trough or sump.
Snorkel. A pipe through the furnace roof,;or an opening
furnace roof, used to withdraw the furnace atmosphere.
in
Spray Chamber. A large volume chamber in a flowing stream where
water or liquor sprays are inserted to wetjthe flowing gas.
Sprue. A vertical channel from the top of
conduct the molten metal to the mold cavity.
the mold used to
Tapping. The process of removing molten metal from a furnace.
Tuyere. An opening in a cupola for introduction of air for
combustion.
!
Urea Formaldehyde Resins - An important class of thermosetting
resins identified as 'aminoplastics. The parent raw materials
(urea and formaldehyde) are united under controlled temperature
and pH to form intermediates that are mixed with fillers
(cellulose) to produce molding powders for patterns.
Venturi Scrubber. A wet type of dust collector that uses the
turbulence developed in a narrowed section of the conduit to
promote intermixing of the dust laden gas with water sprayed into
the conduit. j
Washing Cooler. A large vessel where a flowing gas stream is
subjected to sprays of water or liquor to remove gasborne dusts
and to cool the gas stream by evaporation.
Wet Cap. A mechanical device placed on the top of a stack that
forms a curtain from a water stream through which the stack gases
must pass.
Wetting Compounds - Materials which reduce the surface tension of
solutions thus allowing uniform contact of solution with the
material in question. Sodium alkylbenzene sulfonates comprise
the principal type of surface-active compounds, but there are a
vast number of other compounds used.
1028
*U.S. GOYEMMEIIT IMKIIHS 0 BflOE : 1982 0-381-085/44r7
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