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P.O. Box 1606, Palmer Lake, CO 80133
Tel: (719) 488-9640, Fax: (866) 453-8473
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Tin/Lead Electroplating Module
-Titration Analysis Techniques/Lead Analysis
Lead (as lead sulfate) Analysis
If you have not done so, please read the DOs and DON'Ts section now.
- Titration flask (125 ml)
- 10 ml Automatic pipette
- Digital titrator
- 1 mL syringe
- 0.5g and 1.0g measuring spoons
- CDTA, 0.800M titration cartridge
- pH 6.00 buffer powder pillows
- Hydrogen peroxide, 30%, ACS
- Methylthymol blue indicator powder pillows
- Rochelle salt
- Using the syringe, measure 5 mL of bath into the 125 mL flask. Add approximately 45 mL of deionized water.
- Using the 0.5 g measuring spoon, add 1 spoonful of Rochelle salt and swirl to dissolve.
- Add 1 mL of 30% hydrogen peroxide and swirl gently to thoroughly mix. Wait approximately 1 minute to allow the peroxide to oxidize the dissolved tin.
- Using the 1 g measuring spoon, add 1 spoonfil of hexamethylenetetramine to the sample and swirl to dissolve.
- Add the contents of 1 ea. PH 6.0 buffer powder pillow and swirl to dissolve.
- Add the contents of 1 methylthymol blue powder pillow and swirl to dissolve. The sample solution should now be blue.
If the sample does not turn blue, the pH is too low. Add an additional 1 g spoonful of hexamethylenetetramine before proceeding.
- Titrate the sample with CDTA solution to a straw-yellow endpoint. Record the number of digits (NUMLEAD) needed to reach the endpoint.
- To determine the concentration of dissolved lead (Pb metal), use:
Pb (metal) = NUMLEAD x 0.0414 g/l
Pb (metal) = NUMLEAD x 0.00553 oz/gal
- Assuming that you are using LeaRonal SolderOn Lead Concentrate (SLC) with 450 g/l lead metal and want to operate your bath at the optimum point of 11g/l of lead metal, the amount needed to replenish the 38 liter (10 gallon) bath is given by:
SLC needed = (266 - NUMLEAD) x 0.0035 liters
SLC needed = (266 - NUMLEAD) x 0.00092 gal.
The acceptable range of digital titrator readings is:
|Acceptable Range Pb metal:
||9.0 to 13.0 g/l
||217 to 317
HANDLE WITH CARE
Always wear protective clothing, acid resistant gloves, and a full coverage face shield
when handling this or any other corrosive material.
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