Caustic Concentration Dropper Bottle Test as a Function of

Sodium Hydroxide and Sodium Carbonate concentration.

1.0  Purpose

1.1   To provide reliable data to galvanizing pickle man and  to determine when to add more caustic to the tank.

2.0   Reagents

2.1   CAUSTIC TITRANT:  Dilute hydrochloric acid solution ( HCL).  Caution  solution is corrosive.  Read MSDS before using.

2.2    CAUSTIC INDICATOR:  Phenolphthalein indicator. ( pH Sensitive)

3.0    Procedure

3.0    Obtain  a representative sample from the middle of each caustic tank.

3.1    After solution cools to room temperature, place a 1 ml (cc)  sample into a 50 ml flask.

3.2    Add 20 ml (cc) of distilled water to the flask and swirl to mix.

3.3    Add three drops of caustic  indicator (Phenolphthalein) .  Solution should be red.

3.4    Add titrant ( hydrochloric acid solution) dropwise, mixing after each drop,   until red solution turns to clear (white).

4.0   Calculating Results:

4.1   Each drop  it takes to turn the solution  clear ( white) = 0.5 % Caustic.

4.2   Typically 3 to 4 oz per gallon of dry caustic is = to 3.00 to 4.00 %wt Caustic tested.