17
epproximate efficiency chock .on the Mme addition and ayclens as a
control device was made voiig'o saterial belanse.
Plueride in kiln feed:

3.6 tons/nr (raw rock) x 2,000 1b/ton 2 1.9 fluoride = 137 b/w
Flueride in kiln product:

1.8 tone/br (proguct) x 2,000 1b/toa x 0.184 Plucrids © 6 lh/sr
Fluoride im exhaust gases: 137 lb/hr ~ 6 Ib/ar = 191 Ib/he from Kiln
to control device.

Since the threo stack samples evereged 1ka lb/hr fluoride

“ exitted, little cdvantage can be credited to the control device. Analy
sis of the particulate collected in the eyclone uns about 1 percent
fluoride. Both the Montana State Board of Health lsboratory end Rocky
Mountain Phosphetes, Inc. lnhoratary sgree on this concentration. This
lov concentration of fJuoride in the cyclone product would iodieate low
fluoride collection efficiency.

Dote available from a sintler plant in Florida shows the
efficiency of thelr control device to be slightly over 90 percent.
SULFUR OXIDE BIsstoNs

Sulfur Giowlde ond sulfur trioxide enlesions are given in
tablo 3 end teble 4, respectively. Significant entssions of sulfur
caides were not expected in the den ecrubber. This assuaption was sub-
stantiated by one sacple, end no additional semples were token.

_ When operating normally, vith Line addition, the kiln steck
eemples analyzed 4,200; 2,285) and 2,460 pon sulfur dtoxide. The
average of the three samples gives an approxtaste eaiasion of Th lbs/hr


FUMIGATION CONDITIONS THAT MAY BE EXPECTED:

Clark Fork valley, downstream (to northwest)

Valley volume was estimated by measurements of contour spacing
at various points along the valley. The measurements were continued
down-valley for a distance of about 4 miles (measured along the valley,
not a straight-line distance), to the point where Warm Springs Creek
enters Clark Fork. The effective top of the valley was estimated at
4,600 ft msl for these computations, and it is assumed for these purposes
that the plumes would remain within this volume.

Assuming a drift of the plumes of 2 mph along the valley and emis-
sion rates (total from the two stacks) of 427 lb/hr of fluorine and
760 1b/nr of 80, fumigation conditions would produce a concentration with-
in this valley Grea of 470 ugm/m? of fluorine and 820 \1gm/m3 of S05.

Little Dlackfoot valley, upstream (eastward)

A similar estimate of the valley volume was made, but it was
limited to a distance of 2 1/2 miles upstream.

With the same assumptions, a fumigation concentration within
this valley of 600 ugn/m’ of fluorine and 1050 ugn/m” of SO, is obtained.

Clark Fork valley, upstream (southeastwara)

Map deta is insufficient to provide a satisfactory estimate of
valley volume for a significant distance upstream. However, the cross
section of the valley within the first 1/2 mile or so suggests that
similar concentrations would be found within this valley also.

The figures given above are rough estimates only and assume a ~
uniform mixing within the entire portion of the valley used in the volume
estimate. However, the valleys are of variable cross section and the
concentrations under fumigation conditions will vary inversely as the
cross section of the valley. .

Under inversion conditions accompanied by light winds, it is
possible that the plume from the kiln stack will not be trapped in the
valley. If this plume escapes, the concentrations estimated for fumi-
gations will be reduced for fluorine by about one-third; and for SO,,
by over 95 percent. It is likely that this plume will be trapped or
partially trapped most of the time, but meteorological data available is
not sufficient to estimate the effective inversion heights with confidence.


%,

pnericea Rito Health Ancociation, Ine., New York City, 1960, pages 123
to 125.

Tae Muoride wae distilled with steam using sulfuric acid distilling
over at 165° C, ‘The distilling flack 4s known ns the Aleoa flack, vhich
ia used extensively by the alweime companies for fluorine distillation.
Thies ie acteally a Clateoa flask with the neck to which the delivery tube
fe attached sealed cff with glass.

ARALYTICAL PROCEDURE

Pipet a suitable aliquot and @tlute to S0-ml. Add 10 ml of mixed
“yengeat end read the eboorbance at 570 mi. If the absorbance falls
beyoad the calibration curve raage, repeat the procedure usiag a soaller
semple aliquot.

CALCULATIONS

pee fivorides = (2:53)(20"3)(6)(7, (P.)(8,)
(wR)

C = Conrentration - 1g

© Distillation dllutioa factor

= Sample dillution factor

«= Sexple teaperature

= Volme of sample (at sampling coaditions)

a? opt Ww? a?

= Pressure et sauple meter

REFERENCES ,

Bellack, Ervin and Schouboe, P. Je, “popta Paotometric Determination of
Fluoride in Water.” Analytical Cheatstry, 3, 2032-36 (December, 1958).

Belleck, B., "Simplified Fluoride Distillation Method.” JAWWA 50,
530-6 (April, 1958).


2.

approximate results:
Rocky Mountain Plant

Average emission at Allowable enissions
. time of stack analyses, per Florida proposal,
Operation pounds (F”)/hour pounds (¥ )/hour
Mixer and Den 204 1.25"
Kiln se 7 0.6
. Total 426 . 2.85

*oh-nour/doy operation

. Tron the foregoing, it ig obvious that a substantial reduction
of emiesions would be required at the Garrison plant, if the proposed
Florida regulations were applied. ;

_ In view of the lack of fluoride emission standards, a more
simplified approach must be taken to arrive at an allowable fluoride

" emission rate for this plant. One such approach would be the require-
ment that fluoride emissions be controlled to a degree that is usually
attainable in similer processes. The emission from the mixer and
den ia the larger source of fluorides, and ita effluent 1s discharged
from a relatively low stack. Methods now in use to control similar
emissions and processes include simple spray tovers, packed towers,
and various high energy devices, such as jet scrubbers and venturi
serubbers. Published data indicate that even multiple pass spray towers
achieve fluoride removal efficiencies vell above 90 percent--often as

high"ae 99 percent. In Great Britain where industrial operatious are
generally controlled by the “chemical efficiency” that can be attained,
the emission limitation for this same type of process is 0.143 grains

Po per cubic ft. Applying this criteria to the plent under study,

: results in the following:


OAMPLING PROORAB

Bvery effort was made vo conduct, camping vhen the plant ws
operating contimuously ond at a uniform feed rate. ‘This, it developed,
was practically impossible. The feed rate 4g based upon hatch addition
of superphosphate to the kiln. ‘This ie accompliched ty using a rubber
tired tractor with a front-end leader. The plant manngement esames
this vehicle, when loaded normally, to hold 2,000 Ibe. One Joed fron
thi truck 4s placed into the kila feed hopper ovary 15 minutes, result-
dog in a feed rate of about 4 tonc/hr. In ectual practice, the capacity
“ef thie loager can vary greatly. During the sampling, a typical truck.
toad of kiln feed ws weighed ond found to contain only 1,250 pounds.
Later curing the veck, tyo other truckloads of feed vere weighed. these
tvo loads weighed 1,750 pounds end 2,440 pounds, respectively. Fron
the kiln feed hopper, the guperphosphbate passed through a bucket clevator,
breaker, hopper, Syntron feeder to a belt feeder. The capacity of this
equipeent waa greater then that provided by the normal four loads per
hour. fhe result was that material vas not fed to the kiln continuously.
Ueunlly, 10-12 minutes would be required to feed one truckload through
thie equipsent. Until the next load vas placed in the feed hopper, no
material was added to the kiln.

Feed rate to the kila wag alco affected by frequent equipment
feitures. During the week of sampling, there yere usually several break-
downs per day. On most occasions, repairs were instituted quickly 50
that the feed could be started in sbout an hour. if repaire were not
too difficult, the kiln contimed to operate, During these mechanical


Teble 3. SULFUR DIOXIDE EMISSIONS
ROCKY MOUNTAIN PHOSPHATES, INC. - GARRISON, MOREANA

Exission ,
Sample — : eoncentration, Raission,
Bo. Date Sempling location Operating conditions Pom Ib/aet db/or
Ape 819-6k Kiln stack Rorsal 4,200 0.695 x 1079 1,02
20-6 8-20-64 _ Ellm stack Normal 2,285 0.378 x03 566
ake G21-6h Kila stack torral 2,860 0.602103 5
abs 8-21-64 “Kiln stack Without lime addition 6,07 1.008 1073 sz
218 6-21-64 Kila steck Without line eddition 2,600 0.430% 1073 365
22° 8-22-64 Scrubber etack Nornal 380 0.063 x 1073 22

“# Ten perceat moisture accused in kilm stack gases. MNornal variaticns in moisture content will sot

have en appreciable effect on magnitude of the exissions.

Serubber oteck gases are assumed to contain 5 parcent moisture (saturated conditicas at 110° P
stack temperature).

ALL conceatretions are on a wet basis and at standard conditions of To” FP end 29.92 inches of
mercury.


is

Seeegeray

tes:

‘D = Neutral stability

1

fey
ow
°
§
ad
3
u
§
o<7
oO
oo
S
°
:o
3
38
t
ne
S
3
Z
u
oO

vorides 1 be
(Total from both sources) gm/i no



Cee 3

kh. She necessary leborstory analyses of the samples will

be dene hy the Montana State Board of Health.

Following court proceedings in June and July 1964, a formal request
was received by the Public Health Service to initiate the stack test work
as outlined above. This request wes contained in a letter dated July 15,
196%, from Pr. John 6. Anderson.

_ The stack teat team conoisting of Richard W. Gerotle, Roger
Ghigehara, John 8. Henderson, and fon R. Goodwin (all of the United states
Public Health Service) arrived in Helena, Montana, on August 17, 1964.
“Stack sempling et Rocky Mountain Phosphates, Inc. began on August 18, 1964.

Mr. Ben Wake, Industrial Hygiene Engineer, Montana State Hoard of
Health, assisted in the stack testing. ALL analyses of samples were
performed at the Montane State Board of Health daboratory by Mr. lndwig
Champa, Chief? Chemist.

THE PRODUCTION OF DEPLUORINATSD PHOSPHATE ROCK

GEHERAL COMMENTS

Rocky Mountain Phosphates, Inc. is engaged in defluorinsting
Nontena phosphate rock to wake it suitable for une in animal feed supple
nent. As &@ fertilizer, it is not essential that fluorine be completely
eliminated; however, for use az a mineral supplement in livestock and
poultry feeds, flyoriae mst be almost completely eliminated. Montana
phosphate rock as used in this plant contains on the order of 3-5 percent
to 4.2 porcent fluorine. ‘he plant specification on the fluorine content
of deflucrinated rock product is 0.18 percent fluoride. ,


REAGENTS

Sodium ae

pe. I (Approxtwate) Sodium Rydronide: Dissolve 40 gm MeOH pellets in 50
and dilute to 1 liter.

Concentrated Sulfuric Acid.

Silver Sulfate

Spadas: 4,5-dihyaroxy-3 (p-culfophenylazo}- 2, 7-naphthaleaedisulfonic
acid trieodiua salt. a
Spadne Solution: Dissolve 0.959 gm Spadas in 1,0 and atlute to 500 mi.
, 24 de 0 te

Concentrated Hydrochloric Acid

Ldrcony] Chloride Octahydrste Solution: Dissolve 0.133 ga 2r0Cl,"8 Ho
in 25 mi B60. Add 350 = concentrated RCL and dilute to 500 al with #0.

Reference Bolution: Dilute 7 m2 concentrated Heb to 10 ml with H,0. Aaa
20 mi Spadne solution to 100 al HO end add the HCl colution. Hix well.
This solution in used to set the zero point and is stable indefinitely.
Iitxed Reagent: Hix well equal parts of the Spadne solutioa and #r0Cl*

8 8,0 solution. This reagent is stable for at least 3 montha, :
Gotiwa Fluoride (Reageat Grade). ;

Fluoride Standard: Dissolve 3.0987 ga dry MaP ang dilute to 1 liter.

Dilute 2 mi of this solution to 1 liter, This final solution coataina
1.4 pe/ed. : , : ;

-Pipet 0.0, 10.0, 2.0, 30.0, 40.0, end 50.0 ml standard BoP solution
Auto separate W00-al beskera. Ad@ 50.0, 40.0, 30.0, 20.0, 10,0, and ,
0.0 mi H,0, respectively, to the beakers. wher add 10 nl of mixed


ws
eulfur Gtoxide. Two seples vere analyzed without Line addition. These
analyzed 6,070 and 2,600 yom or an overage ef 603 lb/hr sulfur diextdéa.
Wath Mine addition, the threo sulfur trioxide muples analyred
125,473, end 596 pps or cpproxinstoly 123 lb/hr. With limo injection
into the stack gases, the resulto were 667 end 1,020 pp culfur tricaico.
This would be about 148 lb/hr of oulfur trioxide. Apparently, the Mino
Gees remove cot Of the sulfur oxides.


Grble 6. MISCELLANEOUS BAMPLEB

SOCKY MOUNTAIN HIOSPMATE, IHC, - GABRICON, MONTANA

Semple mucher fype of eaample Reoultsa of amalyais
20-1 Kiln stack aludge 0.175% fluoride
20-2 Superphoxphate (5-aay-ola) 2.5 9 fluoride
23 Superphocphate (2-day-ol€) 1.96 # fluoride
-k Particulate collected in

eyelone 0.9 % flusride
20-8 Kiln otack particulate 0.0425 fluoride
2-10 Buperphoaphate (60- day-old) 1.6 $ flucrige -
22-7 Raw phosphate rock - 4.2 4 fluoride
22-8 Phoophoric acid 0.95 & fluoride
22-8 Phosphoric acid 4 ¢ P05
aa bea scrubber sludge 9.97 & fluoride



Table 2. FIUOMILE BdssIcis
ROCA MOUNBAIN PUQUPHATES, INC.
GABRIZOR, NOMTARA

Seaple : - Sampliag Operating - ‘Bulaston ecacentration,” Suissions,

lio. Tate = eentdon conditions ppm Aw/ocr eats? infer
19-1 IGS = Kn tack Borneo 2,07 0.102 51073 1,630 253
2-5 BREA «Kn otc _ Borma 1,500 9.078 2 079 1,180 no
Qed G26 = Kn tack Borsa 2,200 0.108 x 1073) 1,730 162
rk 26h =n tack Without live addition 3,150 0.155. x 1073 2,80 132
On6 S26 tn stack Without line addition 2,620 0,123 x 10°F 2,050 wa
22 8-26 —Seubber stock Bormal 12,000 0.989 2 073 9,430 206
2%  B-2%6h Serubber stack Borne] 18,439 0.905 = 3073 14,500 37
226  G2n6h  derubter stack Boral 19,30 0.995 x 17> 15,100 ap
eneeone _

@ Ten percent anioture ancuted 4a kiln stack gasoo. Boreal variations ia anloture contest will not
have an appreciable effect on aagnitude of the eaiesions.

Borubber stack gnees ore assumed to contain § percomt soisture (catumnted conditsono ot 110° F
otack tenyerature).

All concentrations are on 8 vet bests ond at atandnrd conditions of 70° F and 29.92 inches of coreury.


rengent to each beskor, [ix thoroughly end read tho absorbance ot
STO me. Pilot comcentrmtion vs absorbance of a reotanguler greph paper.

At least one point chowld be run with eneh comple aad each time that
© anw batch of mixed reagent io rade. It ic isportant that etandards
and samples bo at the sane texperature as cach degroe difference eausce
about 0.02 mg/liter error.

SAMPLING PROCISURE

Set up the apparatus as shown im Mgure 1. Ada 100 mh 0.1 N ReGa
to each of the first two ixpingers, leave the third ary to cateh any carry-
“over. Gi24ca gel rey be placed in the fourth impinger to absorb aay
additional moioture (this holps to protect the xeter and pump). Put
sore ice in the beth. Dray the cample through the train at 1 cfm for
30 minutes or as suitable. Record neter temperatures and prescures at
10 mimte intervals during se=pliag and obteia an average. Reeord the
baranetrie pressure.

BAMPLE PREPARATIO#

Trensfer the solution ead its 1,0 washings from the throe ixpingera
to a 500-mk volumetric flack and dilute to the nark. Pipet a guitedle
voluse (25 to 50 al has been foumd adequate for 25 cu ft stack samples
fron power plants) and dilute to 300 ol with 1,0. This 10 used for the
@stiletion, ,

DISTILIATION PROCEDURE

‘Uso the nothod of Uilard and Winter oo described is "standard

Methods for the Tnemimation of Vater end Uastexater,” lth eattion,


RESULTS
VELOCITY TRAVERSE

Data on the velocity traverses are given in table 1. Three
velocity traverses were mado on the kiln stack) the first two were rade
when the plent was operating normally vith Mme addition. These dats
were collected on August 18 and August 20. ‘the results were 24,500 ecfa
and 25,600 ecfu. During the check of the effectivesess of line addition,
the velocity traverse gave a stack velocity of only 15,400 scfm. The
reanons for this lover value ere not cleor. Sone reduction in gas flow ;
‘ts due to the fact that the lime-addition blower wae not operating.
It 4s doubtful if thie can explain conpletely the lower stack velocity.
It 4s more likely thet the reduction 1s caused by variation in plant
operating conditions: i.c., fuel gas rate to kiln.
FINORIDE Biestons

All fluorine exissioa data throughout this report includes both
perticulate and gaseous fluorine emissions, vhich are expressed as
fluortée fon (?"). The results of the fluorine sampliag are given on
table 2, Highest concentrations were found in the effluent gos fron —
the superphosphate den. Three samples were analyzed. The first, efter
only one-half hour of operation, indiceted a fluoride stack gas concen
tration of 12,000 ppm. The second end third sauples were takzen after
2-1/2 and 6 hours of operaticn. By this tima, the concentration of
fluorjde in the scrubber stack had reached 18,430 pra and 19,320 ppm,
respectively. ,


ROCKY MOUNTAIN PHOSPHATES, INC.
GARRISON, MONT.

PLANT LAYOUT
[RAW ROCK
1
| ea ocx STORE: Lp |
poy
_ wl one
PUMP | 2
——— ‘Ip usa
—_—__, Ley, PBS ACID:
cee weer ‘STORAGE
PLASTIC} boa oo :
“LINED RETURN |
POND | a
; SJ Mix SULFURIC
a, HOUSE &i| . in.
; Fen Le PHOSPHORIC
Ble:
; BIg!
TRAILER COURT: Sle:
(ML)! ‘B

wie

“NOTE:

Drawing not to scale.’

COOLER

[|

BRAGGING &
| “STORAGE

OFFICE:

UAB;

oO ~<
y ROUTE. #10:

NORTHERN PACIFIC RR. |

S

~ ‘TO. GARRISON (% MI.) :

ROUTE. #12}

i
TO HELENA =~”

“Sketch 2 -


‘Figure 1. SAMPLING TRAIN FOR SULFUR OXIDES

FILTER’
| TUBE

“CONTROL VALYE .
FF THERMONETER

BALL & SOCKET

_ NANOMETER —

| ASTM DI266 LAMP SULFUR.
ABSORBERS


- Hravogen Feroschic
Dilute 30 percent 10, with Kp ata@ 1:10 ratio. Prepare fresh

daily.

Barium Chloride (BaCl,‘2.0, Reagent Grate}

0.0200 B Bartum Chloride

Dissolve 2.2216 BaCl,* 2,0 in ml HO and Gilute to 1 Miter with
Asopropyl alcahol.
Thorin Indicator O-( 20hytroxy-3, 6-diswlfo-]-naphthylazo)
Benzanearsonic acid disodiua salt
* 0.2 Percent Thorin Indicator
Dissolve 0.2 ga Thorin indicator in 100 al 1p.

SANPLING PROCEDURE

Set up the apparatus as show in figure 1. faa 30 ml 60 percent
doopropyl alcohol in the first scrubber and 10 ul in the filter tube.
Aad 50 ml 3 percent HW, to the third scrubber. A little silicone grease
on the upper perts of the joints my be used to prevsnt leakage. Heat
the probe so that no condensation occurs while sampling. Sample at a
rate of about 2cu ft per 30 minutes while eumpling. Mecord the tank —
vacuum and temperature initially end at 10 mimite intervals. Note the
baranetric presaure. ‘
 Biscomect the probe, heating tape, and adapter and allow te cool.

Comect the spare absorber and ada 50 ml) 3 percent #0, to act as an air
filter, Replace the water in the fce-water bath with tap water. Draw


through rotameters. Flow is initiated by air pressure on the acid

storage tanks. Phosphate rock ic fed at @ rate of 16 tona/hr by a screw
conveyor, ‘he resulting slurry falls into the 20 ft x 40 ft x 20 ft high
concrete structure called a den. ‘The reaction continues in the den for

6 to 12 hows. After this time, the material is removed by a rubber-
tired, frontebucket truck loader and is transferred by a belt conveyor

to the storage shed. If the superphosphate is not removed within 12 hours,
it "sets up" and becomes very difficult to remove.

Vent gases (containing fluorides) are removed from the den by a
blower snd are passed through a vertical open-tower water scrubber to the
atmosphere. ‘The scrubber is a 10 ft diameter tower about 17 ft high with
a 5-1/2 ft diemeter by 15 ft high stack. Water is mumped from a small
pond (80 ft x 50 ft x 3 ft deep) to the scrubber sprays. The water returns
to the pond by gravity. Occasionally, lime is added to the pond to neutrae 4% ©
lize the pond water. In the top of the scrubber, above the sprays, a steel
grating supports a 4 to 6 inch layer of stone and lime. Fluorides are ®
removed from the vent gases by reacting them with this lime.

DEFIWORINATION OF SUPERPHOSPHATE

The superphosphate is alloved to age a minimum of 24 hours before
being introduced into the rotary kiln. Depending on the age of the super= _
phosphate produced, the fluorine content will average between 1.5 to
2 percent fluoride. ‘he feed to the kiln is on 6 semicontinuous basis.
Actucdhly, charging is accouplished by a front-bucket truck loader at the
vate of one load every 15 mimites. Each load weighs about 1 ton, and
the plant assumes, therefore, a feed rate of 4 tons/hr. ‘the crude


Several methods are available for the reduction of fluoride
contant of phosphate rock. Rocky Mountata Phosphates Mberates part of
the fluoride by mixing phosphate rock, sulfurie seid, cater, and phos-
phoric acid to form triple superphosphate. Fois mix, after aging a
minimus ef 2b hours, is caleined in a rotery kila at te=peratures up to
2,800° F; this substentially volatizes all the fluorine. Sulfate cor
pounds formed, in the superphosphate reaction Give decompose in the kiln,
evolving considernble quantities of sulfur oxides (sulfur dioxide end
sulfur trioxide). :
, Te flew diegran and plant layout are shown on sketch 1 and
sketch 2, respectively.
SUPDSPHOSPHATS PROBUCTION ;

The raw phogphate rock ig mined within % alles of the plaat.
After being reduced im size, (65 perceat through 200 wesh) 1t ie delivered
to the plant in trucks. ‘Three vertical silos are used to store the rew
rock. Serey conveyors remove the ground rock from the storage silos and
discharge it to a belt feeder. The belt feeder discharges iato a amall
feed hopper above the mixing den. .

Sulfuric acid and phosphoric acid are received im railroad tenk
ears and are stored in horizontal storage tanks. The sulfurie acid ic
normally about 96 percent sulfurie acid made from aeelter off-gas in
Anaconda, Montana, The 52 percent phosphoric scid is purchased from
J. Re Simplot of Pocatello, Idaho. In the formation of the superphocphate,
the sulfuric acid, phosphoric aeid, water, and phosphate rock sre mixcd
in a GWA mixing cone. The cone is 2 ft in diencter by 20 inches high with
a 4 inch outlet in the bottom. The acids are motered into the cone


Because of the physical arrangement of the piping, 1t was
impossible to sample upstream of the scrubber and thereby check the
efficiency of the fluoride rexoval in the scrubber. For thia reason,

@ fluoride balance wes made around the superphosphate cen.
Fluoride im feed naterial: ;

1. Rock: 16 tons/hr x 2,000 Ib/ton x 4.26 fluoride = 1,340 lb/br

2. Phosphoric acid:

4 tons/nr x 2,000 Ib/toa x 1% fluoride = 8 lb/hr
Total toput fluoride 1,420 lb/hr

" Mluoride in den product:

30 tons/hr x 2,000 1b/ton x 1.9% fluoride = 1,140 1b fluoride/hr
Caleulated fluoride evolved in the den vould ber
©. ayaa abfar = 2,280 Ib/ar = 260 Defer

The stack analysis (table 2) shows that the average ewission rate
of fluoride was 234 ib/hr. ‘This rate indicates little, if any, fluoride
ie yeroved in the scrubber. The fluoride balance 16 only an approxizatéon,
but it doea indicate relatively low efficiency for the den scrubber.

Table 2 indicates fluoride concentrations in the kiln stack gases}
however, it aust be resenbered that the kiln stack eniseians are on a
ai-hr/dey basis while the superphosphste den emigsions are for only the =.
limited time vhich the den operates--usually 6 hr/batch. When operating
with Mae additios in what is considered normal operation, the kiln :
stack samples analysed 2,070) 1,500; and 2,200 pym fluoride. ‘The average’
of the three sexples regulted in en eniesion of 142 lb/hr fluoride. An


RAW ROCK

TO ATMOSPHERE
A

SAMPLINGs]
| POINT

$

aocxy HouNTa MPPyoseuares, inc.
GARRISON, MONTANA
FLOW DIAGRAM
9/21/84

SULFURIC.
ow

TVA MIX
COHE

__ SUPERPHOSPHATE

“TO STORAGE;

SUPERPHOSPH

——_

HATE

- FROM STORAGE
|

K

)
TH evenone/
TACK

LINE

ACID:
ATER

ING

Pe

FEED HOPPER.

ACID

PHOSPHORIC.

-TO ATHOSPHERE
ia .

WATER

VENT

PRODUCT
COOLER”

GAS BLOWER

—

| wATURAL GAS

MAKE-UP =|

PLASTIC LINED POND

GRINDING, SCREENING

. BAGGING &
STORAGE BUILDING

Sketch

i


Teble 4. SULFUR TRICKIDE Hisslous
SOCKY MOUMPAIN PHOSPHATES, DNC. - GARRISON, MONTANA

. Exissicn ,
Eeaple - " * concentration, Eaissica,
Ho. Date Sampling location Operating conditions = pps Ib/ser s/o
193 &19-6h Kalla steck Sorzal 125 (0.0% xw > = 39
20-7 8-20-64 Kil stack Normal 473, 0.098 x 10°F
21-3 821-64 Kiln stack Porm - 595 0.123% 20°3 Bh
2-6 8-21-64 Kiln stack Without line addition 667 0.1338 x 1079 a7.
a9 8-21-64 Kila atack Without lise addition 1,02 0.211% 2079 479
223 822-6 Scrubber etack Normal 19.027 x 0730

| # Gan percent moicture assumed in kiln stack gases. Normal variations in roisture contest will
not have am appreciable effect on magnitude of the enicsions.
Serubber stack gnoes are asmuced to contain 5 percent noteture (satursted conditions ot 110° P
stack texperature).
All concestrations are on a wet basis and at standard conditions of 70° F and 29.92 inches of
mercury.


SSCA OS ae RAMAEMOT MESSI)
ROCKY MMIRAIN NIOSHYSS3, Ime.
GARREIOU, NORA,

AOUET 18992, 196

Donald 8. Goodwin
Chewlesi inginesr

in cooperation with the
Montama Btate Board ef Health

U.S. Public Health Service
Divisions of Air Poliutien
Teelmical Agsistancs Granch


u,
estinatca from meteorological dispersion coleulotiens. While thooe
ealeulations are not exact, they can serve o5 guidalinos in air corpling
and pollution control applications. Our enleulations (attached) indi-
eate the following maximum ground level concentrations for the conditions
assumed: |

1) Don eniscions

Maxdewm concentration of approximately 10 ppm as ”
occurring with a near neutral atmosphero at a wind speed of 11 mph

. and at a Giotanse of about 330 ft. fron the serubber dischargo.

If current fluoride enissicus wore reduced 95 porcont,
this caleulated maxima ground concentration would be reduced to an
estinated 0.5 ym.

. Alco of interest is the estimated ground level conecn-
tration of 6.5 ppm ac F” which could be expected at approximately 660 ft.
from the serubber discharge. This level vould be reduced to ehout .3 ppm
4 the den emiosions were reduced 95 perceat.

2) Kiln emissions

The cotimated maximum ground level of P from tho kiln
is expected to occur with an unstable atmosphere (looping plume) and
arQ mph wind. The concentration vould approximate .14 ppm at a distance
of about 1300 feet from the kiln stack. Reducing kiln emiscions by

90 pereent, vould reduce this concentration to approximated .02 pra.

For the morning invercion brenkup (fumigation) ease, which
appears to be important in Garricon, the fluoride levels are estimated


the wooden baffles is provided, gao strcem bypascing will

occur; thus, the fuld effect of a four-pans scrubber would

Rot be obtained. The velocity treverce of the scrubber stack

indicated that bypassing was occurring.

&. Physical inspectica of one pass of the acrubber chowed

three of the eight nozzles to be completely covered with a

crystalline deposit, indleating that these spray nozzles

were not functioning. .

3- otal water Ploy rate to the scrubber wea approainately

50 gym.

DEPIAORINATION ow SUPERPHOSFRATS

Superphosphate feed to the definortoating kiln usually overages
2. 5 to 2 percent fluorine. Practically all of this fluorine, down to
at leact 0.18 percent, ust be removed before the product is ouitable
for animal feed suppleent. This is sccoupliched by subjecting the
superphosphate to temperatures up to shout 2,400° F. ‘There is also an
apparent decomposition of calcium mulfate, resulting in the formation
ef gulfur oxides.

The method of ewission control spplied by Rocky Mountain Phos-
phates is lime injection into the exhaust ges strean from the kiln.
Subsequently, the exhaust gas atream is passed through a cyclone separ
rator. the theory is that the lime will renct with the pollutente ond
form edlid particulate caspounds, which can be reroved in the cyclone-
type ceparators. Variations of this technique are used in eimilar situ-

ations, Some deficiencies were noted in this aysten:


CONTROL DEVICES
SUPERPHOGPUATS FRODUCETON ;

In the defluorination of phosphate rock as conducted by Rocky
Mountain Phosphates, Inc., superphosphate production fe the imitial step.
Sulfuric acid, phosphoric acid, water, and phoophate rock are mixed and
aged. Normily 4a cuperphoaphate production, 15 te 40 percent of the
tagut fluorine is eaitted from the mixer and den. The fluorine 4s usually
Ja the form of silicon tetrefluoride (SiF,). other constituents of the
effluent stream would be carbon dioxide, stems, and coma sulfur dioxide,
, A commonly used abatenent device to reuove the fluorine from the
nixitg den effluent goo is a high intensity scrubber using copious
quantities of water or fluosilicic acid up to about 2 percent by weight.
Rocky Mountain Phosphates utilizes an opem-tower scrubber as a contro)
deviee. The scrubber is a 10 ft dimneter vertical tower divided into
four quadrent-type passes by baffles mace of @-inch lusber. It is an
open tower vithout pecking or grids. Gas flow 1s arranged so that flow
ie eocurrent in two passes and countercurrent in the other two passes.
Approximately 32 spray nozzles are provided, 6 ia each pase. Viswl
observations made during the gtack sampling showed sone deficiencies in
design end operation of the ecrubber: _

J, ALL vertical baffles have about 6 inches of clesranes

between the bottom of the baffle and the base of the

scrubber. ‘he Liquid outlet frou the serbber 1s a 6-inch

Pipe installed flush with the bottan of the scrubber.

Since no velr or any other method of sealing the bottes of

uit M0 gaen(P-4)


GROUND LEVEL COUCEVFRATIONS (ppm)

‘ i
sce, 40’ yoo! yoo
vind speed. Source Pollutant 1/16 mt Yom Went 13m 6 mt 2.25 af 3-2 et
A Kila FL 3.87n1079 q-17aio"* 1.532107? 2.012072. ©
En T mph @,avtre0"? r.aoxi0"3 2.352072 3,02x1072
,  Serubber F1 6.75 1.28 h.ozzio7? 4.022107?
vse 80, 1.66107 3.35mi07 9.83x1073 9.832078
Kiln Fl 3.3020 2.37107? aesteioTM? 7.75x107° 1.872077
Sum 9 ooh So, 5.aax1072% 208x107" 2.08x107? 1.192107} 2.902107?
; ; 1 “1 “2
noe 4 Serubber FL 5.02, 4.5 9.181072 2.01z1072 3.8810
. LAUMTR Oe . - -
(10 4 we 50, a.e3207? 1.30x107) 2.26810" 4.681073 9.83207"
0 an on 1.298107? 522.107 2.58210" 6.75x10°* 4.302107?
aa oh £0, 2.cox107® 7,66n1972" b.05x1073 1.022107) 6.36x10"*
eh Serubber rl 1.0710 | 6.45 Zeb 1.35 a.agao7>
pre 50, 2.641972 1.622072 B.51x107? 3. 3¢n10°? 2.80x1073
pgs? i PUME CENTER-LIWE COSCENERATIONS (ppa)
(¥ Shee" ite Pu 7.3ex10° — 2.72x107 2.8710 8.19 7-307?
yw & roh 82 aatxt93 2.27107 ‘25x10 1.2710 1.19
_Serubber Fl 2.bkz10? 3. baxd0* 5.7hxl0 1.5810 Lbs
‘ 80, 3.6220 8.52 1.80 400x107 3.66x107°



CALCULATIONS
ppa 8, or 90, by voluve = 6.8 x 107(a-8)(H)(F)

P,P
we
(ary basta) tee
Rh
where A= ml 0.02 M BuGl, used for titration of camplo

Be» nl 0.01 N Bath, used for titration of blank
Na emet normlity oP Boll,
Ps dilution factor
T= final tank teuperature, °
, = initial tank tesperature, °R
v, s volume of tank, liters
P, = final absolute tank presaure, in Bg
(Pz = (BR, - fined veemm)
P, = initial eboolute tank pressure, in a,
(2, = (P, - initial vac)

REFERENCES

Shell Development Company Analytical Department, “Dotermination
of Sulfur Dioxide and Sulfw Trioxide in Atack Cased,” Emeryville Method
Series 4915/59a.


5.

at’ .0$ non for current coteston lovele and .0S pom 4£ tho propoced contro}
efficiencies were achiovea.

She plant's valloy location with ite numerous morning inversions
and the Reck of Aetniled neteorological data maken 1% tcposcible to
accurately dosunent the degree of control noeoncary to eliminete
mulcance corpleinto end prevent excessive cequmilation of fluoride in
vegetation. Xt will, thercfore, be necessary after a poried of

, operating experience at the reduced enissioa rate to determine if

* edoquate eontrel has been realised or whether further reduetion io
Reeded. Tho bacis for such determinations could be tho analyses of
freshly grow vegetation to determine if tho floride content hee
beon reduced to 40 ppn or less. ,
SULFUR DIGMENG EWssrous

A nunber of communities have regulations liniting concontration
of sulfur dioxide 4n emissions to 2000 pro. Tho plant under otudy
emita 2300-200 ppm in the kiln ctack goose which vould be in violation
ef such regulations. Other regulations 1imit eniosion of sulfur dioxide
on the basis of concentrations at ground love) beyond the plant prenioes
due to the emissions. A reasonable reguintion of thie type would limit
Qround concentrations to an evorage of 0.5 pm for a one-hour poricd,
not to be execedod during more than tuo ese-hour periods during any
seven-day period and an average of 0-1 pra fer o 2h-hour ported, not
to be excecded during more than ene 2i-hour porded in any throe month
period. ;


Draw air through the system for 15 minutes and remove the spare absorber.
Disconnect the thira serubber and transfer its contents and ite
water washings to a 250-al volumetric flask. Dilute with water to the
mark. Amalyse this for 50).
Stopper the first scrubber and apply suction to the filter end.
Remove the suction line and allow the partial vacwm in the first scrubber
to draw the solution fron the filter. Rinse the filter tube with 50
percent isopropyl alcohol béfore the suction is lost. ‘Transfer the
contents of the first serubber and ite washings to a 250-ml volumetric
* flask and dilute to mark with 60 percent isopropyl alechol. Analyze this

for 50,. .

. ANALYTICAL PROCEDURE

Sulfur Trioxide

Pipet a suitable aliquot to a flask and dilute to 100 ml with £0
percent igopropyl alcohol. Add a few drops of Thorin indicator (enough
to give a yellow color), Titrate with 0.02 B BaCl, to the pink end
point. Make a blank determination in parallel.
Sulfur Dioxide

Transfer a suitable aliquot to a flaek and ada 4 times this volume
of isopropyl alechol. Dilute to 100 mi with 80 percent Asopropy) alechol,
add enough Thorin indicator to give a yellow color, and titrate with
standard 0.01 8 BaCl
in parellel.

2 to the pink end point. Run a blank determination


superpbormmate to elevated ay a buckot clevater to a breaker in hich
large laugs are reduged in aize and are metered onto a Kila feed belt oy
6 Syren feadex. ‘The feed rote to the balt 4 unlfem wut not contdmen.
Qwite often, the feed hoyges ic aupty befare Che 15 mimmte charge period
hao elapsed. The Kiln to fired with natural gee and has 0 maximum tom
yeratare of 2,400° to 2,900" ¥. The retention timo of material in the
Bin is ohoat A dours. Efeck gars fros the Infln are diecharged into ae
& ft dlewater x 230 ft high ctack. Air ie used to ocolk the dafinarin:ted
profust as At passes to storege. ‘The produnt de sold im bolk or bagn.
Vertien steel afios are provided for bulk mioraga, eal bagging machines
are provided fos bagged product. ,


Gfeble 1. STICK FLOW CONDITTORS
ROCKY MOUMRAIN PMOSPHATES, IRC. GARRISON, BOPARA

Plast VYoluss at Voluze, ef at
operating steck condi- Velocity Stack std conditions
Date _lecation condition tions, ofa ft/sec ture JOT, 29.
8-18-64 Kiln stack Normal 46,600 15.5 365° P 24,600
8-20-64 Kiln stack Gorsal 50,500 16.7 nue? p 25,600
8-21-64 Kiln stock Without — 29,900 9.9 4b° F 14,900
. Line .

8-22-68 Scrubber Formal 7,600 - ue Pp. 5,950

stack



DIFFUSION ESTIMATES FOR GARRISON, MONTANA

UNSTABLE TO NEUTRAL CONDITIONS

Ground-level concentrations beneath the plume axis were computed
for various distances under the assumption that a plume traveling along
the valley would spread (diffuse) in a manner subject to usual diffusion
calculations for a distance up to 5 kn (3.1 miles), These concentrations
are tabulated for the kiln and scrubber separately, and a graph is prepared
showing a distribution of concentration down wind, assuming the two
sources to be immediately adjacent. Maximum values may not appear since
computations were for specific distances only. The summed values reflect
in nearly every case the contribution from one or the other source, and
in no case are they significantly greater than from the greater source
alone. >

Plume center-line concentrations only were computed for stability
class F since under stable conditions the plume may not lower to the
valley floor but may impinge on valley sides with maximm concentrations
approaching those within the plume itself. These concentrations are also
tabulated. n

All computations are based on the following emission rates:

Kiln 141 Ib F*/hr 738 2b So,/hr
Scrubber 286 lb F-/hr 22 Ib SO,fhr

EFFECTIVE STACK HEIGHT

The Holland equation was used to estimate effective stack heights
based on the following data:

Kiln stack Serubber stack
Diameter 8' 0" 5' 67
Height 210! 35°
Stack velocity 900! /min ~  600'/min
Stack temperature 4oo° F at 30° 112° F .

Air temperature: 60° F, Pressure: 900 mb

Effective stack heights were found to be:

Wind speed 2212/2 mph Umph -7Tmh .
Kiln stack 233 ft 256 ft 286 ft -
’ Scrubber stack 39 ft 46 ft ko ft

The Holland equation is considered relatively good for neutral
atmospheric stability. Even under unstable conditions it appears that
effluents from the scrubber stack will remain within the valley since
the stack velocity and temperature are both very low.


GROUND LEVEL CONCENTRATIONS (gn/m>)

Steb{ lit; ¢ Pays
want Bo be 295
wind speed Source Pollutant 1/16 mi__1/8 mi 1/6 mi 1/3 mi 6 mi 1.25 mi 3.1 mi
A Kiln Fl 1.310735 sao" 12x10 14nd"?
7 mph 80,  6.5x10 2.6x10°°  5.6x10"" 7.110
syn -3 4 -h -5
km nce eee ot Scrubber FL 4. 7x107j 8.9x10_5 2.8x10"5 2.8x10_
. UOS7 A Ge k 50, 39x10 74x10"? 2.3x10°?_ 2. 3x10
Kiln Fl 2.3x10733 9.5x10" 9.5x10"? 5 4x0”? 1. 3x07
Dum: B 80, 1.2x10 4.9x10 4.9x10°" 2.8x10°" 6.8x10
9 mph Scrubber Fl 3.5x107p 3-1x107F 6.41074 yao”, 2.71072
LOCC ae Ci ora : 80, 2.9x10 2.6x10 5.3x10 1.1x10 2. 3x10
. Kiln Fl 9.0x10"S 3.5x107 7} 1.8x1078 4.72107? 3.0x1077
‘py 50, 4. Tx10 1.8x10 95x10 2.h4x10 1.5x10
11 mph =. Scrubber Fl Telxlo“p 4.5x107p 2.4x107p 9.41074 7-9x10_2
WE THEAL 80, 6 .2x10 3.8x30 2.0x10"" 7.8x10 6.6x10
. PLUME CENTER-LINE CONCENTRATIONS (gn/m3) . 1.
ye -2. “1 j -2 -3 -
(MLL ‘ Kiln Fl 5 .1x10 1.2x10) 2.0x10"" 5.7x10 5.1x107
° = 4 Eph 80, 2.7 6.4x1072 1.0x1072 3.0x107* 2.71073
: -2 -2 -2 3
Ex Lo Scrubber Fl 1.0 .2.4x10: 40x10 1.1x10 1.0x10
DONS ayes” 802 8 .5x10" 20x10"? 3.3x1073 9. lix107# 8.6x10~?



DETERMINATION OF GULFUR DIOXIDE AND SULFUR TRIOXIDE

SCOPE

When sampling stack gases for various concentrations of sulfur
Aloxide and sulfur trioxide, this method ia used.
APPARATUS.
Sampling Probe

Gisse tubing (wreferably Vycor or quarts, Pyrex) of suitable size
with a ball joint at one ena and a removable filter at the other. (6ne-
| half inch OD 'x 6 ft. long Pyrex tubing has been used.)
Filter

A Buchner filtering funnel with a ccarse fritted glass to support
a remowble filter is required to remove any particulate or acid mist.
Kaolin wool (resin-free), fritted quartz, or glass wool (Pyrex brand
Ho. 3950) are suitable filters. i
Adapter : .

Six plug-type connecting tubes, 24/40, one with « 90° bend with
& socket joint.
Heating Tape

A heavy insulated heating tape with a variable voltage supply ~
ie needed to prevent condensation in exposed portions of the probe ang
adapter. Alternatively, glass wool or other suitable insulators may be
used if temperature extremes are not too grest.
Calibrated Tanke

Tvo evacuated tanks are required to provide an accurate sample
volume measurement. One cubte foot tanke have been used satiafactorily.


INFROVUCTION

In Joly of 1963, discussions began between staff macbere of the
Division of Air Pollution, U.S. Public Health Service, and representatives
of the Montana Stote Board of Health concerning the operation of a phoe-
phate defluorination plant at Garrison, Nontana. This plant, owned by
Rocky Mountain Phosphates, Iac., began operation in Garrison in Suly-
August 1963. f&hortly theresfter, the Montana State Board of Health
received suserous complaints about the operation of this plant.

At the request of the Moatens State Board of Health, the United
States Public Health Service agreed to sssiet ia performing enalyses of
the stack effluents from the plant. ‘he agreement is outlined in a letter
Gated Novesber 27, 1963 by D. F. Walters, Public Health Service, to
Tr. John &. Anderson, Buecutive Officer of the Montana Stato Board of
Health. Briefly, the agreement wes as follows:

i. The U.S. Public Health Service wilh provide the equip-

ment suitable for obtaining the necessary stack Samples

and will lean this equipment to the Montana State Board of

Health.

2. The Montana State Board of Health will make an arrange-

nent for entering the plant end for providing the necessary

test holes and scaffolding. _

3. The Technical Assietance Branch of the Division of Air

Pollution, U.S. Public Heelth Service, will supply two men

“to assist in conducting the stack teste. -


SSS

3.

7,600 of x 0.143 grains x__ 1b x GQ min x19 IDF" = h.2 o/h
ef

7,000 ar hr db Py
Cand .
percent reduction: 284 - 42 = 98.5 pereent

Ym view of the practical possibilities otea obove, it is sug-
gested that an average efficiency of 95 percent be specified ond
maintained for emissions from the mixer and den oporation.

Ascuning thet the total fluoride enfesions froa the mixer end
den operation were 95 percent controlled, the control of fluorides
from the kiln would probably not have to exceed 90 percent because
of the toll stack.

Applying 95 percent control te the mixer and den and 90 percent
control to the kiln stack, the total fluoride emisolons would be as
follows:

Kiln; = 182 Ib/hr x 0.10 = 14 lb/hr

Den: 284 Ib/pr x 0.05 = 14 Ib/pr - .

28 lb/hr

The 28 pounds per hour would be the total ollowble emission
regardless of production rates, control equipment efficiency, or specific
source.

‘An indication of the improvement in air quality that might be
achieved 1f fluoride emissions are reduced to 28 Ibs/hour ean be


SUGGESTED GUIDES FOR EMISSION STANDARDS AND AMBIENT AIR QUALITY CRITERIA
. OR ROCKY MOUNTAIN PHOSPHATES, INC. AND GARRISON, MONTANA

FIVORIDR EXISSLONS

Fluorides in general and gaseous fluorides in particular are
important as air pollutants, first because hydrogen fluoride (HF)
end ailicon tetrafluoride (SiF,) are toxte to some plante in concen-
trations as low as 0.1 part per billion and secondly; because fluorides,
both gaseous and particulate, may be accumulated by vegetation.
Animals which consume vegetation containing in excess of 30-50 ppm

+ fluoride can develop fluorosis.

fhere are no regulations applicable specifically to stack emis-
sion rates for fluorides in the United States. One such regulation,
however, has been proposed for Polk-Hillsbarough Counties in Florida.
This regulation might not be directly applicable to the plant under
study as it coula be unnecessarily restrictive. The Florida proposed
requiation 1s designed for use in an area vhere there is a large
number of fluoride emitting plants. ‘The propogal, however, 41s of
interest as a reference point and as an indication of performance whtch
can be achieved. The proposed Florida regulation would limit emissions
of fluorides to 0.6 pounds per ton of PLO, produced in the manufacture
of phosphoric acid and calcined or defluorinated phosphate rock. In
the mamfacture of normal phosphate, superphosphate or normal super-
phosphate, the proposed emission limit for gaseous and/or water soluble
fluorides (F") 48 30 pounds per operating day per plant. Applying these
standards to the Rocky Mountain Fhosphate plant, gives the following


12
failures, caxpling we continued. Vor major sepeire requiring over
1 hour to complete, it wao usuol practice to stop the kiln and reduce
the fuel feed rate to the kiln. At these tines, ecompling was delayed
until operating conditions returned to normal.

Tt ws also normal plant practice to ecase operating the kiln if
the meteorological conditions vere such that the kiln stack plune wes
blowing toward 6 acarby troiler court or toverd Garrison. Yor the firat
3 days of the stack sempling, the westher was cool, and the wind ws
strong fren the northwest. During thie tine, mo clutdowas vere made
because of meteorological conditions; however, on the last 2 days of the
tent, three chutdouns vere mate because of pollution in Garrizon ar the
trailer court. The frequency of these shutdowns is chown on table 5.
During the first 23 days of August, the plant stopped kiln feed 26 tines
vecause of pollution being transported to one of these inhabited areas.

Another factor which made uniform sampling difficult was the age
of the kiln feed. Digested waterial fros the mixing den is aged a
ninimu of 2h hours before being fed to the kiln. Fresh material will
normally contain higher percentages of fluorine. Efforts were made :
during the sampling to feed the kiln with freshly digested mterial.
This was not always possible since there was also a supply of &-day-old
material in the storage building. ,

Lime is normlly added to the kiln stack gases. This Mme is
thought to react with fluorine compounds to form particulate caleiun
flworide, which can be removed from the stack gas and thereby reduce
fluoride emiasions. Me plant log inflestes that the rate of Line


1b
bottom of the stack. Because of this condition, particulate sempling
wee considered to be impossible and vas discontinued.

Pollewing the stack test with the plont operating rormally an
ettenpt was mafie to detormine the effectivences of Mime addition by
eompling without line addition. Four samples wore teken under theco
conditions--tuo samples of fluoride and two osrples of sulfur oxides.
All of these sampleo were taken on tho efterneon of August 2).

On August 22, the plant operated the superphosphate producing
feeilities. The capacity of these facilities is conciderably greater
“than the defluorination kiln capacity so that they are only operated
every other dey for a period of 6 hours. Feed conditions during the
edzing are uniform. The rock is fed at a uniform rate by a screw feadier
waile sulfurie acid, phosphoric acid, and water fead rates are metered
by indicating Zlow meters and are controlled by hand velves.

Gases evolved from the cuperphosphate den are exhausted by 6
blever and discharged into an open-tover liquid serukber. The serple
connection was located in the upper part of the serubber above the oprays.

fhe major pollutants from the den ere fluorine compounds. dfter
the mixing den hea been operating ebout one-half hour, a semple ms
collected for fluoride analysic. Following thic, a cample was collected
ond asalysed for sulfur Goniéo and qulfur tricsids. Significant emtsaioas
of sulfur oxides were not encountered. Following the sulfur oxide sample,
two emmples vere teken for fluoride analyaic. ,

One veleeity troverse ma made on the scrubber stack.


SIBSIARY

Rocky Moantaia Phoaphaves, Ine. operatos a plant ot Garricon,
Montema, which profucen doflucrinated phoophate rock for woe fa onimal
feed eugplemest. Stack emissions frou thio plant have reculted in
menexous cexplaints frou lecal vesidests. fe aasesa these complaints,
the Montana State Beard of Health requested the 0.8. Public Bealth
Sorvice's asatstance in conducting stack eoupling at the plant. Sarpling
was conducted in Auguet 1964. ‘The ecrubber steek on the cuperphoophate
Dining dea and the htln stack of the auperphoophate- defluorizsting kida
vere cempled for fluorides ang culfur oxides. Tho Serubber stack ums Pound
to contein 32,000 to 19,000 pra Zlucridee. The kiln otack gases contained
1,500 to 2,200 ppm fluarides; 2,200 to 4,200 ppa aulfur dioxide; and 125
to G00 pa sulfur trioxide.


THERMOMETER

SAMPLE PROBE . _— ; |
Wo { tf ic
i =
~ ICE-WATER i” ‘° (3)
Bare W W W MANOMETER |
PUMP
GREENBURG-SMITH DRY GAL METER .
IMPINGERS

SAMPLING APPARATUS
FIGURE |


Table 5.

OPERATING AQW PROM PLANT 109
ROCKY FQUNTATN HHOSPTADS, TIC, - GARRISON, DORTATA

AUBUBE 196)

No. of 50 Id bags

Bo. of tires plant chut down

approximate ef line added “betauae of pollutants blewing in
Bate re operated to kian otack gas Pralier court Garrisons
8-2 27.5 29 2 2
&2 12.0 w 2 -
3 16.5 eal 1 a
Bs 6.0 45 a 2
85 - - - -
6-6 ° 2.0 - - -
&T 22.0 7p 1 -
8-8 18.0 10 2 -
&9 2.5 10 - -
8-10 6.5 5 « -
el 17.5 5 - -
G12 15.0 9) 2 i
81 19.0 20 a -
8-2! 8.0 22 - 1
6015 19.0 E-¢) 2 3
8-16 27.0 22 1 2
8-17 14.0 22 - 1
818 21.0 37 - -
8-19 17.0 33 - -
8-20 22.0 61 - -
821 20.5 33 - 1
6-22 14.0 32 1 1
823 18.5 48 “2 2
Average Grand total
26.

15.7 hr/day


SADLS OF CONTENTS

SROARY

TWFRODUCTION 2 2 we ee ee ee tw ee

PRODUCTION OF DEFIWOCRINATID PHOSPHATE ROCK .

General Comments . . 2. ee eee

_GSuperphosphate Production . .

Pefluorination of Superphosphate

Flow Disgram . 6. ee eee
Plent Layout 26. ee
CONTROL DEVICES 2.6. ee eee
Surorphosphate Production. . .

.

ry

.

Pefluorination of Superphosphate

SAMPLING PROGRAM 66. 6 ce ee
RESULTS 2.0 ee ee
Velocity Traverse... 6. 6 «
Fluoride Baissfons .. 6.5 «
Sulfur Oxida Balesions .. . .
fable 1 - Stack Flow Conditions
fable 2 - Fluoride Baissions .
Toble 3 - Sulfur Oxide Ralssion

"fable 4 - Sulfur Trioxide Bulssions

.

°

re)

.

.

.

.

.

Table 5 - Plant Operating Tata...

Table 6 - Miscellancous ameples. . .

APPENDIX

Fluoride Sempling and Analysing Procedure
Sulfur Oxide Sampling ond Analysing Procedure

.


6.

Agaia referring to the attached calculated ground level concen-
trations, it 19 estimated that the 50, concentration (from the den
servbber) reaches a maximum of 0.26 ppm at about 330 feet fram the
source, with a near neutral atmospheric stability and a wind speed
of 11 mph, .

‘The funigation level 1s ectinated at 0.45 ppm to which the kiln
emission is the major contributor. Since this concentration is very
close to the suggested level of 0.5 pom for 1 hour, 1t is felt that

+ the sulfur dioxide concentrations in the kiln effluent esses should be
Limited to 2000 ppm at stack conditions. :
SULFUR TRIOXIDE EMISSIONS
, Regulations applicable to emission of sulfur trioxide and
sulfuric acid mist have been used by only a few agencies. The only
‘one reasonably applicable is 0.3 grains per scf expressed as 100 percent
“gulfuric acid, a regulation of the San Francisco Bay Area Air Pollution
Control District. The kiln stack of the plant 4n question was enitting
gases containing 0.2 to 1.1 grains per standard cubic foot (an average
of 0.7 grains per scf) when lime was being added to the kiln effluent
gaces.

Another way to view the emissions of sulfur trioxide is to
extinate ground concentrations on the basis of exissions, stack height
and meteorological dispersion formulas. In thie manner, we estimate
that, ground concentrations of sulfur trioxide, calculated as 100 percent


DETGRMINATION OF SOLUBLE FUJORIDES
SPADNS-cINCONTUM LAKE METHOD

SCOPE
Tris method is used for the determination of soluble fluorides ia

stack gases. Accuracy within 0.02 mg/liter in the concentration range

of 0.00 to 1.40 mg/liter is cbteinsble. ‘The interferences from stack

gases mocessitate distillation of the samples.

APPABAIR

Seupling Prove: Olaes tubing of suitable size (12 inch by 6 feet long

Pyrex Drand tubing hao been used).

‘Sopingers Your standard Greenburg-Suith ispingers.

Ice Bath: Ice bath with a sultedle rack far holding iapingers.

Dry Gas Neter: One cubdic foot/revolution meter.

Manopeter: A 36 inch Hg manometer,

Yeoum Puapt Paap with control valve.

Thermometers: 0-200° C ena 0-180° F range.

Bolling Flask; One-liter, round bottos, long asck, Pyrex boiling flask

with joint awber 24/40. ;

Connecti

. HT

Beads: Two to three dozen —
Spectrophotoneter: Beckaan wodel B.

.


Bete en -

pee he ee ee ce ee ce ce a ~~
: ne = : °
EE oo : e
; : : e
f i ch t in -
co t t t Ht lo
+ + = io
# : i : .
i
t
i
t t lo

Moderately unstable

Neutral stability

Unstable

Ground-Level Concentration of Sulfur Dioxide

(Total from both sources) gn/m2
{

7 :
i
< : 4
. ef
ai) i it
q \
r i.
HH HH
frat as oy
# EE AE
PEERS FF seissrss|
es fi Biba facet
Bits beaat lw
Hy + i
+ f " 4
n
Ha GAL r
geen ew ee ro = rn a



Yasuum Source
A good vacuum source 1s needcd to ewaemte the calibrated tanks.
An absolute pressure of ebout 5 laches of moreury should be achicvad.

Iheraaneter
Manoueter

A 36 inch mereury mnoneter
Lany Sulfur Absorber

Three ASTM D1256 Jemp sulfur cbsorbers with coarse sintercd plates
Filter Tube ,

Filter tube with a 40-om diancter Corning medium sintered plate

Teflon Tubing
Teflon tubing, one-quarter inch ID, for connecting oerubbera

Alternatively, 8 ma Pyrex tubing with ball ana socket connections may
be used.
Ice-Water Eath
Surette
$0-nl and 10-ml purettes

REAGENTS
Daionized Uater
: Deionized water should be used instead of distilled water.
Iecpropyl. Alcohol
80 Percent Tsopropyl Alechol .
_ Dilute dsopropyl aleohol with HO at a ':2 ratio,



2. Considerable ancunts of the lime dust settle out in

the duct between the kiln and the cyclone separator.

Doors have been provided, and the ducts are cleaned at regular
intervals. This would indicate poor contact between the

lime and the pollutant compounds and, therefore, incomplete
reaction.

2. Samples of the solids collected in the cyclone were
analyzed and founda to contain lesa than 1 percant fluoride.
This wruld indicate poor contact and reaction between lime end
fluorine.

3. The cyelone provided at the plant 40 10 ft in diameter

by 10 ft straight aide with m 15 ft high conical bottom.

, Inlet velocity to the cyclone averages between 25 to

4g ft/sec. Inlet velocities should normally be at least

; 50 ft/sec. ,

4, The bottom outlet of the cyclone was only partially
sealed. The actual opening was donut-sheped and was

18 inches in diameter by about 2 inches across. Periodi-
cally, duct fell to the ground from this opening, but, most of
the time, air was draw into the cyclone by the atack draft.
Air entering the cyclone through this opening interfered with
the dust collecting efficiency of the cyclone operation.


Re
sulfurte acid, could on occasion reach or oxacea 0.2 ng/m?. Watle
there are no asbient air quality standards for sulfuric acid mict ,
in the United States, there is conoidereble cxpert opinion that if a
peak concentration of 0.3 mg/m? is not exeecded, no detrimental
effects on health will be observed. For this reason, it is cuggested
thet 80, concentrations in the kilm stack be Mmited to .3 graino/stendard
cubic foot.
VISIBLE BATSSIONS
The steck sampling tean was unable, because of procoss conditions
in the stack, to measure total particulate emissions from the plant.
However, it was obvious that there was conciderable particulate natter
‘in the plime. These enissions could be regulated on the basis of
visual obcervations of the plume. Such a regulation would limit the
discharge of any contaminant for a peried of three minutes in any one
hour, which would obscure an observer's view by greater than 40 percent.
This type of measurement is based upon tho Ringlemann chart which is
also applied to black or gray smoke. A 40 percent equivalent opacity,
which we are suggesting, for the Garrison ctanderd is equivalent to -
No. 2 on the Ringelmann chart. This type of regulation is enforced in
many arens of the United States.
“Control devices applied to reduce other emissions may reduce the
“particulate emissions. Therefore, if the plant could demonstrate o solid
, pafticulate emission of 0.1 grain per standard cubic foot or leas, tho

visible emission opacity regulation could be waived.


13
addition varies considerably, end, during the veek of the sampling, it
waa higher than for any wock of the month of August. ‘These data are
tabulated in teble 5.

Yaitial sampling ws conducted on the rotary kiln eteck gases.
A sampling hole was provided 11 ft above the stack inlet at an elevation
of betwren 30 and 35 ft above the base of the steck. During the initial
teat, dime wes added contimously to the stack gases leaving the kiln;
this 4s normal operating procedure. The samling was conducted on
August 18, 19, and 2. Velocity traverses were made on the 18th and 2th.
‘qhree sauples were collected for fluoride and three, for sulfur oxides.
The samples vere collected in the sequence: fluoride, mulfur oxides,
fluoride, sulfur oxides, etc. ‘hie resulted in a set (fluoride and
sulfur oxide) of samples being taken on each of three successive days.

On August 20, en attenpt wea nade to obtain a perticulate sample
from the kiln stack. After 10 minutes of sampling, the flow through
the somple train had practically ceased. This was thought to be due to
coating of the sample train filter by the white, pasty material encountered
in this stack. Additional heat was applied to the filter, and all sapling
wes stopped. After ebout 15 nimtes, sampling was xesumed, but egain the
sample flow rate was extremely low. Sampling was stopped, and the equip-
ment wan disnantled. Examination revenled the filter had beea costed
with a white, pasty precipitate. Apparently, this material is formed in
the upper regions of the stack and falls into the base of the atack.
Doors had been provided in the bottaa of the stack to resove this materiel
periodically, At the tine of the test, thie sludge was 2 ft deep in the