Ion Exchange Purification of Trivalent Zinc Passivating Solutions

Ion Exchange Purification of Trivalent Zinc Passivating Solutions Presented to The National Environmental Partnership Summit 2007 New Orleans, LA May 8, 2007 Michael P. Mc. Monagle President, Superior Plating, Inc.

Special Thanks • Cindy Mc. Comas • Karl De. Wahl • Steve Kocha

Zinc Plating

Zinc Plating • Most commonly used • Lowest priced • Offers Anodic Corrosion Protection to Steel Parts

Zinc Plating • Conversion Coatings (passivates) • Retards White Rust Formation of Zinc • Choices are: » » Clear Yellow Black Olive Drab

Zinc Plating 4 Hours Salt Spray Exposure With Passivate Without Passivate

Zinc Plating • Conversion Coatings • Hexavalent Chromates were standard for years • Trivalent Passivates now available for Clear • Yellow and Black can be produced with dyes and top coats

Zinc Plating • Conversion Coatings Most commonly finished are Yellow and Clear Hexavalent yellow gives more protection than Hex Clear or Inexpensive Tri’s

Zinc Plating • Conversion Coatings • New Trivalent Conversion Coatings are available with corrosion protection greater than Hex. Yellows • 120+ Hours VS 96 Hours (ASTM B 117 Neutral Salt Spray)

Zinc Plating • Conversion Coatings • Advantages of Trivalent Conversion Coatings: » » » Excellent Corrosion Protection No Cr +6 Safer for Environment, Employees Complies with EU Directives (WEEE/Ro. HS, ELV) Helps meet OSHA Cr PEL Uniform “Blue Bright”

Zinc Plating • Conversion Coatings • Disadvantages of Trivalent Conversion Coatings » Does not provide inhibition to uncoated areas » Not Self-healing » Less tolerant to Zn and Fe* » Expensive make-up and operations (approx 20 X)* * reasons for purification process

Zinc Plating • Effects of Contamination: • From Zn – source is the deposit itself • Above 2000 mg/l » Reduced corrosion protection » White, cloudy appearance • From Fe – source is uncoated area of parts • Above 100 mg/l » Reduced corrosion protection » Dull, yellowish appearance

Ion Exchange Purification • ATOTECH Tricotect System

Ion Exchange Purification • The ATOTECH Tricotect unit is a fully automated ion exchange system. • Uses a selective cation IX-resin. • Unit is leased to users of ATOTECH trivalent passivating solutions.

Ion Exchange Purification • Operations at Superior Plating, Inc. • 11 months experience • Connected by manifold system to three different tanks • Process tank volumes range from 440 to 2500 gallons. • On-line purification cycle ranges from 4 to 6 hours.

Ion Exchange Purification • Operations at Superior Plating, Inc. • Consistently maintains Zn below 2000 mg/l (1500 to 1800 mg/l normal range) • Consistently maintains Fe below 100 mg/l (60 to 90 mg/l normal range)

Ion Exchange Purification • Operations at Superior Plating, Inc. • Economic Analysis » Annual Cost Factors Include: make up costs treatment costs labor costs equipment lease cost maintenance costs utility costs reagent chemical costs

Ion Exchange Purification • Operations at Superior Plating, Inc. • Processing without Purification Bath #1 Vol. (gals) 440 Make ups 24 Costs($) 14400 Bath #2 750 18 18000 Bath #3 2500 14 30900

Ion Exchange Purification • Operations at Superior Plating, Inc. • With Purification Bath #1 Vol. (gals) 440 Make ups* 1(? ) Costs ($) 6200 Tricotect($) 3400 Totals ($) 9600 Bath#2 750 1(? ) 9100 3500 12600 Bath#3 2500 1(? ) 7500 6900 14400 * need to monitor Cu and Pb but could be 18 to 24 months bath life

Ion Exchange Purification • Summary of Benefits: • Consistent Product Appearance • Consistent Corrosion Protection • $26, 700 Annual Savings (approx. 42%) • 660 Pounds of Chromium not used AND not discharged to the environment.