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OAR Box 1313 

Preppedby LaTeiaShed 

Document Number: 

8) l-B-1 

Docket Number: 

A-88-02 

Printed 6/12/2008 9:03:27 AM Sheet 8 of 99 
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0 A-88-02 

MIDWEST RESEARCH INSTITUTE 

4505 Creedmoor Road 

Raleigh. N.C. 27612 

Telephone (919) 781-5750 

X-6-\ 

r 

Date: December 26, 1984 FILE 00 

Subject: Site Visit—Greensboro Industrial Platers 

Survey of Chromium Emission Sources—Chrome Plating 

EPA Contract 68-02-3817; ESED Project 85/02 

MRI Project 7711-L 

From: 

To: 

Barb Duletsky .yfi 

Al Vervaert 

ESED/ISB/SSS (MD-13) 

U.S. Environmental Protection Agency 

Research Triangle Park, N.C. 27711 

I. Purpose 

The purpose of this site visit was twofold: (1) to gather background 

information on this chrome plating plant, and (2) to determine the 

suitability of this plant for chromium emissions testing. 

II. Place and Date 

Greensboro Industrial Platers 

725 Kenilworth Street 

Greensboro, North Carolina 27403 

(919) 274-7654 

October 29, 1984 

III. Attendees 

Greensboro Industrial Platers 

Robert Hester, Vice President 

U. S. Environmental Protection Agency 

Jim Crowder, Chief, Standards Support Section 

Stan Cuffe, Chief, Industrial Studies Branch 

Al Vervaert, Lead Engineer 

Midwest Research Institute 

Barb Duletsky 

Charles Hester Z J*N '8,99, 

Principal Laboratories 425 Volker Boulevard, Kansas City, Missouri 64110 
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IV. Discussion 

During the plant visit, there was a discussion with plant personnel 

about the chrome plating operations at Greensboro Industrial Platers. 

This discussion was followed by a tour of the facility. 

A. General 

The Greensboro Industrial Platers facility is a job shop primarily 

engaged in the hard chrome plating of such items as textile parts, 

hydraulic parts, and woodworking machinery. Some decorative chrome 

plating is also done at the plant. Based on the number and size of the 

chrome plating tanks, and on the chromic acid consumption, Mr. Hester 

considers it to be a medium-sized shop. Other processes performed at 

the plant include polishing, grinding, and sand blasting, as well as 

copper and cadmium plating. The plant was built in 1955. There are 

22 employees working one 10-hour shift, 4 days/week. 

This plant is one of few facilities in North Carolina that perform 

hard chrome plating. There are many decorative platers in North Carolina, 

but most of them are captive platers. That is, decorative chrome plating 

is usually performed by the companies who produce the items to be plated 

and also manufacture the final product. (According to Mr. Hester, 

Carolina Platers in Greenville, South Carolina, is another job shop of 

similar size to Greensboro Industrial Platers. Carolina Platers specializes 

in plating large rollers for the paper industry.) 

B. Process Description 

There are three chrome plating lines at this plant. A plan view 

of the three lines is shown in Figure 1. There are a total of six 

plating tanks, four on one line and one on each of the others. The two 

large tanks are 6.4 m (21 ft) long, 0.91 m (3 ft) wide, and 1.8 m (6 ft) 

deep. The smaller tanks range from 1.2 m (4 ft) to 3.7 m (12 ft) long, 

and are 0.91 m (3 ft) wide; and 1.8 m (6 ft) deep. Five of the tanks 

are devoted to hard chrome plating, and the sixth tank is for decorative 

plating. 

The solution in the hard plating tanks contains approximately 

0.27 kg of chromic acid per liter (33 oz/gal) of water. Greensboro 

Industrial Platers uses about 454 kg (1,000 lb) of chromic acid per 

month. It is manufactured by Allied Chemical and is purchased as a flaked 

powder in 45-kg (100-lb) containers. Sulfuric acid is used as a catalyst 

in the plating solution in concentrations of approximately 0.003 kg/2. 

(0.33 oz/gal) of solution. There is a laboratory at the plant where 

samples of the plating solution are analyzed periodically to ensure the 

proper concentrations of these constituents. 

During the hard plating process, chromium is normally deposited at 

a rate of 0.001 in. (1 mil) per hour. The density of the current in the 

tanks needs to be approximately 0.35 amps/cm2 (2.25 amps/in.2) plated to 

achieve this deposition rate. The direct current (DC) generator used to 

2 
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ME 

HOOO 

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t*ATTVE 

PUTE frHARD 

PUTE 

(Cr**) 

HARD 

PUTE 

(Cr*6) 

HARO 

PUTE 

(Cr+6) 

RINSE 

-TANK 

,(H20) 

RINSE 

TANK 

(HjO) 

HARD 

PUTE 

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GENERATOR 

Figure 1. Schematic Diagram of Plating Lines 

at Greensboro Industrial Platers. 
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charge the electrodes and maintain the appropriate current was operating 

at a voltage of 5V DC, generating a current of 2,000 A, the day of the 

visit. Some hard-plated parts receive as much as 10 to 12 mil thickness 

of chrome plate. This provides a wear-resistant surface and good protection 

from corrosion and rust. * 

The temperature of the hard plating solution is about 55°C (131°F). 

The tanks are heated by hot water from a gas-fired boiler that is turned 

on at 3:00 a.m. on Monday mornings. The tanks are heated continuously 

until Thursdays at close-of-business. Parts are arranged on racks and 

manually placed in the plating tanks. After plating, parts are removed 

and rinsed with water in a 10,600-£ (2,800-gal) rinse tank. The parts 

are then dried and moved to another area for grinding and polishing. 

The decorative chrome plating tank contains a trivalent chromium 

solution that is supplied by Harshaw Plating Systems. This plating tank 

operates at room temperature and, therefore, cannot be used to build up 

as thick a layer of chromium as can the hard plating tanks. Because 

chrome plate is porous at low film thicknesses, parts must be plated 

with nickel before they receive a decorative chrome plate. The nickel 

provides a nonporous barrier to protect the steel from rust and corrosion. 

C. Pollution Control 

Insulating balls float in the plating tanks and cover about 70 percent 

of the surface of the solution. The balls are made of polypropylene and 

last indefinitely in the tank. They are approximately 3.2 cm (1.25 in.) 

in diameter. Although the purpose of the balls is to limit heat loss 

and misting, there is still a substantial amount of misting from the 

hard plating tanks. Mr. Hester noted that he once tried a chemical 

additive as a substitute for the balls. The chemical controlled misting 

by forming a blanket of foam on the surface of the solution. It worked 

well but it tended to deteriorate after only a few days in the plating 

solution, and had to be replaced frequently. 

Each plating tank has some type of hood arrangement. The older 

tanks have side draft hoods along the edges of all four sides of the 

tank. The hoods on more recently installed tanks draw emissions across 

the surface to the back side only. The plant has also investigated a 

different method of hooding that would reduce the volume of air leaving 

the plant. An air curtain system, whereby air is pushed across the 

surface and pulled into the hood on the other side of the tank has been 

designed by the National Institute of Occupational Safety and Health 

(NIOSH). Any new tanks that Greensboro Industrial Platers installs 

would incorporate this design. 

On each plating line, induction fans draw emissions from the tanks 

through the hoods to a mist eliminator (ME). The ME's are manufactured 

by KCH (see Attachment A), and consist of parallel rods made of polyvinyl 

chloride (PVC). The rods separate and collect chromic acid from the 

V. 
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mist by condensation and impingement. The ME's are periodically flushed, 

and the chromic acid is recirculated to the plating tanks. The plant 

installed their first of three ME's 4 years ago to decrease chromic acid 

consumption. Since all three ME's were installed, chromic acid consumption 

has been cut in half. 

A small amount of sludge is generated in the plastic-lined plating 

tanks as a result of the chromic acid reacting with the lead electrodes. 

The volume of sludge was much higher when the tanks were lead-lined and 

reacted with the acid. 

There are high evaporative losses from the hard plating tanks 

because of the continuous misting of the plating solution. Water from 

the rinse tank is used as make-up water for the solution that is added 

to the plating tanks, thus alleviating the problems of disposal of the 

contaminated rinse water. Clean water is added to the rinse tank to 

maintain the appropriate level. 

Emissions from the polishing and grinding area are captured using 

conventional hoods and enclosures. An induced draft fan withdraws the 

emissions from the enclosures to a cyclone on the roof. The particulate 

matter is deposited in a large hopper, which is emptied every 3 to 

4 months. 

NIOSH conducted a study at this plant a few years ago. The results 

were published in a report called, "An In-Depth Survey Report of Greensboro 

Industrial Platers." As part of the study, the workers wore personal 

samplers to determine their average levels of chromium exposure. This 

is the only available report on indoor concentration levels at this 

plant because no routine indoor monitoring is done. 

D. Economics 

The ME's were purchased for $3,000 to $3,200 each, which represents 

a small fraction of the cost for an entire plating line. The plant 

installed the ME's to save money by capturing and recirculating the 

chromic acid that was previously emitted to the atmosphere. They have, 

in fact, reduced their chromic acid consumption by 50 percent. 

V. Conclusions 

The trip to Greensboro Industrial Platers was very informative. 

During the discussion, a list of potential contacts and other resources 

was generated. The list is presented in Attachment A. 

This plant is representative of most job shops performing hard 

chrome plating. The capture devices work well. Visible mist was observed 

to be drawn across the surface of the tanks into the capture hoods. The 

ME's also work well, as evidenced by the decrease in chromic acid consumption 

at the plant and by the fact that there were no visible emissions from 

A 
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the stacks. Both inlet and outlet testing of the ME's is feasible on at 

least one of the lines. For these reasons, this plant appears to be a 

good candidate for future testing to determine both uncontrolled 

emissions on a typical hard chrome plating tank and the control efficiency 

of a typical mist eliminator. 

Attachment 

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Attachment A 

FUTURE CONTACTS AND PUBLISHED REPORTS 

1. Manufacturer of the mist eliminator 

KCH 

Post Office Box 787 

Rutherfordton, NC 28139 

Attn: Ken Hankinson 

(704) 287-2439 

2. Local suppliers of chromic acid 

Worth Chemicals 

Ashland Chemicals 

Van Waters 

3. NIOSH study: In-Depth Survey Report of Greensboro Industrial 

Platers. November 3-4, 1981. 

Stephanie Spotzwood or John W. Shehee 

NIOSH 

Materials Processing Section 

Engineering Control Technology Branch 

Division of Physical Sciences and Engineering 

Cincinnati, Ohio 

4. Professional association 

National Association of Metal Finishers 

111 East Wacker Drive 

Chicago, Illinois 60601 

(312) 644-6610 

David G. Kelly, President 

National Association of Metal Finishers 

ICO Asko Processing, Inc. 

434 North 35th Street 

Seattle, Washington 98103 

7 
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Contacts from American Electroplaters Society conference, 

January, 1984. 

Alan Haase 

Chief Chemist/Environmental Engineer 

Briggs & Stratton 

Milwaukee, Wisconsin 

David Scherzer 

CBC-Aqua Search 

Oak Creek, Wisconsin 

Bruce E. Merkel 

President 

Bruce Merkel & Associates, Inc. 

Franklin, Ohio 

Charles Darvin 

EPA/IERL 

Cincinnati, Ohio 

Jerry Kohl 

North Carolina State University 

Raleigh, North Carolina 

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