# OAR Box 1313 Prepped byLaTeia Shed



### Document

Number: 

# 73 ) ll-B-47 Docket Number: 

# A-88-0 2

Printed 6/12/20089:03:30AM Sheet 73 of 99 P. 1P. 2 

# l/IRIt ^ A-88-02 MIDWES TRESEARC H INSTITUT ! T5J-e>-4 7 S..;:e.^ •-O l Harriso n Oak

s Boweva

t Carv , N C "5 1

Date : Ma

y20 , 198 8 (Finalize d Jun e 30 , 1988 ) \ \ , \\\l \ 

# 555--Y- : \ V . U

N Subject : Sit e Visit—Lufkin ®\\f* \ «—rr^-' I ..i.} ,

Chromiu m Electroplatin g NESHA P \\\\\\...-- • EP AContrac t 68-02-3817 ; ES D Projec t 85/02 a \V^

- \ MR I Projec t 7717- K From : Robi n Barke r To : Andre wM . Smit h

ESD/ISB/SS S (MD-13 ) U . S . Environmenta l Protectio n Agenc y Researc hTriangl e Park , N.C . 2771 1 I . Purpos e Th e purpos e o f thi s sit e visi t wa s t o gathe r backgroun d informatio n o n th e us e o f th e trivalen t chromiu mproces s a s a replacemen t fo r th e hexavalen t chromiu mproces s fo r decorativ e electroplatin g applications . II . Plac e an d Dat e Lufkin ® Pos t Offic e Bo x 72 8 Apex , Nort hCarolin a 2750 2 (919 ) 362-751 1 Novembe r9 , 198 7 III

. Attendee s Lufkin ® Mat t Caton , Environmenta l Enginee r Midwes t Researc h Institut e Robi n Barke r U

. S

. Environmenta l Protectio n Aqency Gai l Lacy , SD

B Andre wM

. Smith , IS B

/ 'P. 3

IV . Discussio n Th e visi t consiste do f a tou r o f th e platin g sho pfollowe db y a discussio no nth e trivalen t chromium electroplatin g (plating ) process . A . Genera l Lufkin ®i s a divisio no f Coope r Industrie s andproduce s a wid e variet y o f cloth , wood , andstee l measurin g tapes . Lufkin®operate s tw o decorativ e chromium electroplatin g lines . On e lin e utilize s a hexavalen t chromiu m platin g bat ht o plat e high-qualit y stee l surveyo r tapes . Th e othe r lin e i s a nautomate dtrivalen t chromiu m proces s lin e use dt o plat e plasti c tap e cases . Th e platin g line s operat e 1 0 t o 1 2 hours/day , 5 days/week , an

d4 8 weeks/yr . A

previou s visi t t o th e plan t inDecembe r 198 5 wa s conducte dt o obtai ninformatio no nth e electroplatin g o f plastic s an dth e us e o f a trivalen t rathe r tha na hexavalen t chromium bath . Thi s sit e visi t wa s conducte dt o gathe r mor e detaile dproces s informatio no n the trivalen t chromiu m operatio na t Lufkin 3
- . (Fo r mor e informatio no nth e hexavalent chromium proces s a t Lufkin® , pleas e refe r t o th e previou s tri p repor t date dMarc h28 , 1986. ) B . Proces s Descriptio n Figur e 1 i s a flow

diagram

o f th e trivalen t chromium proces s line . Th e plasti c tape s ar e loade dont o rack s tha t ar e automaticall y transferre d throug hth e proces s line . Th e proces s lin e consist s o f a serie s o f tank s use dt o etch , activate , electroplate , an dthe ndr y th e plasti c cases . Th e tap e case s ar e undercoate dwit hlayer s o f coppe r an dnicke l befor e chromiu m plating . Th e trivalen t chromiu m platin g tan ki s 1. 4 meter s (m ) (4. 6 fee t [ft] ) long , 1.1 7 m

(3.8 5 ft ) wide , an d1. 7 m

(5. 5 ft ) dee pan

dhold s approximatel y

2,38 0 liter s (a ) (63 0 gallon s [gal] ) o f platin g solution . Th e typica l platin g tim e i s 4. 0 minute s a t 1 2 volt s and1,60 0 amperes . Th e trivalen t chromium platin g solutio ni s a single-cel l process , Tricrolyte TM III , manufacture db y OMI/Udlylit e Internationa l Corporation . Th e concentratio no f trivalen t chromium i s abou t 3 0 gram s pe r lite r (4. 0 ounce s pe r gallon) . Th e bat hoperatin g temperatur e i s approximatel y 42° C (75°F) . Th e platin g solutio ni s coole db y Teflon TM coolin g coils . The platin g solutio ni s continuousl y filtered ; an

dth e filter s ar e change d thre e time s pe r week . Th e trivalen t chromiu m platin g bat hwa s installe di n198 4 t o reduc e scrap(rejecte dparts ) du e t o "mischromes. " "Mischromes " i s a ter m use d t o describ e anare a o f a par t tha t di dno t receiv e a chromiu m plat e du e t o the poo r throwin g powe r o f a hexavalent chromium bath . A

t first , however , scrapincrease dbecaus e o f blac kstreak s inth e chromium plat e cause db

y plating bat hcontaminant s (mainl y copper) . Lufkin®an dOMI/Udylite' " personne l spen t a grea t dea l o f tim e correctin g th e startu pproblems . Th e plan t finall y

sol dthe origina l bat hbac kt o OMI/Udylit e an dpurchase da newe r generatio ntrivalen t chromiu m solution . Th e ne w bat hha s bee n



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Figur e 1 . AB S plasti c cas e platin g line .

^P. 5

operatin g satisfactorily , and scra p ha s bee n reduce d fro m6 percen t wit h th e hexavalen t chromiumbat ht o les s tha n 2 percen t wit hth e trivalen t chromiu mbath . However , becaus e o f th e bath' s sensitivit yt o contaminants , suc ha s bras s and copper , tigh t laborator ycontro l i s neede d t o maintai n th e bat hwithi n th e norma l operatin g range . A n atomi c absorptio n uni t i s use d t o determin e th e leve l o f contaminatio n i n th e platin g bath . Laborator yanalysi s tim e ha s increase d fro m3 0 minute s a da ywit hhexavalen t chromiu m t o 2 hour s a da ywit htrivalen t chromium . C . Emissio n Contro l Th e trivalen t chromiu m tan k i s equippe d wit hsid e draf t hood s ducte d t o a n evaporato r manufacture d byHeadie . Th e evaporato r operate s a t roo m temperatur e and wa s installe d t o recove r platin g solutio n los t b y evaporation . Platin g bat hchemica l cost s hav e bee n reduce d 5 0 percen t sinc e th e evaporato r wa s installed . Exhaus t ai r fro mth e evaporato r goe s int o a singl e packed-be d scrubbe r manufacture d b yViro n International . A demiste r wa s installe d downstrea m o f th e scrubber . Th e airflo wrat e o f thi s syste mi s 7 9 standar d cubi c meter s pe r minut e (2,80 0 standar d cubi c fee t pe r minute) . Durin g th e visit , n o mistin g wa s observe d a t th e surfac e o f th e platin g tank . Th e curren t emissio n contro l system , excep t fo r th e evaporator , wa s installe d t o contro l mis t fro mth e hexavalen t chromium platin g tan k befor e th e proces s wa s converted . However , th e plan t chos e t o kee p th e scrubbe r and demiste r i n plac e and operationa l t o contro l any mistin g tha t ma yoccur . D . Cost s Th e capita l cos t o f conversio n fro m hexavalen t chromiu mt o trivalen t chromiumwa s $25,500 . Tabl e 1 list s th e component s o f th e capita l costs . Th e majo r componen t o f th e capita l cos t wa s th e purchase d cos t o f th e tw o ne wrectifiers . Th e ne t annua l cos t reductio n associate d wit hth e us e o f trivalen t chromiumi s $28,000 . A s state d above , th e numbe r o f reject s decrease d fro m6. 0 percen t t o les s tha n 2. 0 percent , and th e cos t o f eac hrejec t decrease d fro m2. 5 cent s pe r cas e wit hhexavalen t chromiu mt o 1. 7 cent s pe r cas e wit htrivalen t chromiu m fo r a tota l cos t saving s o f $47,00 0 pe r year . Th e chemica l cos t o f trivalen t chromiumaverage s approximatel y $29,25 0 pe r year , a substantia l increas e ove r th e chemica l cos t o f hexavalen t chromium , whic haverage d $6,40 0 pe r yea r befor e th e conversio n t o trivalen t chromium . Th e plan t di d no t experienc e anysaving s i n wastewate r treatmen t cost s afte r convertin g t o trivalen t chromium . Th e volum e o f sludg e generate d wa s no t reduce d significantl ybecaus e th e plan t stil l operate s wit hhexavalen t chromium i n th e etc hbaths . Th e plan t wa s abl e t o reduc e th e amoun t o f sulfu r dioxid e use d fo r reductio n o f hexavalen t chromium ; however , th e cos t saving s associate d wit hthi s reductio n wa s offse t b yth e increase d chlorin e usag e t o trea t th e high ammoni a conten t i n th e trivalen t chromiumbath . Ammoni a i s use d in th e trivalen t chromium

bat ht o regulat e th e pH .

*P. 6

TABL E 1 . CAPITA L COS T FO R TRIVALEN T CHROMIUMCONVERSIO NA T

LUFKIN® , APEX , NORT H CAROLIN A Component s Cost , $ Equipmen t cost s 1 . Rectifier s (2 ) 15,00 0 2 . Anode s an

d hanger s 1,80 0 3 . Coolin g coil s 4,20 0 4 . Filte r system 3 5,00 0 Modificatio n cost s Trivalen t chromiummakeu p solutio n 4,50 0 Tota l 30,500! * 25,500 °

a Th e plan t had a n existin g filte r tha t wa s use d o n anothe r proces s tank . Th e cos t dat a presente d ar e fo r a ne wfilte r .system . Represent s th e tota l capita l cos t minu s th e filte r syste m cost .



## J~P. 7

E . Conclusion s Th e trivalen t chromiu m proces s wa s installe da t Lufkin®i n198 4 t o reduc e scra pfro

m mischromes . A t first , the plan t hadmajo r problem s wit h th e bat hbecaus e o f contaminatio nan dhadt o dispos e o f on e bat hand replac e i t wit hanother . Afte r 4 year s o f operation , the trivalen t chromium bat hachieve da rejec t rat e below 2. 0 percent . Th e trivalen t chromium

proces s ha s no t reduce dth e cost s a s muc ha s anticipate dbecaus e wastewate r treatmen t cost s hav e remaine dessentiall y the sam

e a s the y

wer e befor e conversion . However , th e plan t currentl y i s satisfie dwit hth e trivalen t chromiu

m proces s an

dwoul dno t g o bac kt o using a hexavalen t chromium bath .