Calcium Carbonate Equivalency (CCE)
- Potassium Biphthalate Solution (0.6476N): Prepare by dissolving 33.0648 g of pure, dry KHP in about 450 mL of deionized water in a 500 mL volumetric flask. Dilute to volume and mix well.
- Standard NaOH solution (0.6476N): Prepare 2.5 L quantity by diluting 113 mL of 40% NaOH w/w into 2387 mL deionized H2O. Standardize by titrating against KHP solution prepared above. Pipet 50 mL of KHP solution into a 150 mL beaker, add a few drops of phenolphthalein indicator and titrate the NaOH into the KHP solution to a permanent light pink endpoint. If exactly 25.00 mL of NaOH is not titrated, adjust NaOH solution and repeat. Protect from exposure to air by a soda-lime tube or other suitable means.
- Standard HCl solution (0.9714N): Dilute 200 mL conc. HCl into 2300 mL of deionized water. Standardize against 0.6476N NaOH by dispensing 25 mL of HCl from a buret into a 150 mL beaker. Add a few drops of phenolphthalein indicator and titrate HCl against NaOH to a permanent light pink endpoint. If exactly 37.50 mL of NaOH are not titrated, adjust HCl solution and repeat.
Phenolphthalein indicator: Dissolve 1.0 g phenolphthalein powder in 70 mL of ethanol, add 30 mL of deionized water and mix well.
- Weigh exactly 1.0 g of sample and transfer quantitatively into a 250 mL conical beaker.
- Add 25.00 mL of 0.9714N HCl, add about 50 mL of deionized water, cover with a watch glass and bring to boiling on a hot plate for 5 minutes. Remove from heat, cool and rinse condensate from watch glass back into beaker. Also, rinse walls of beaker with minimal amount of deionized water.
Add a few drops of phenolphthalein indicator to sample and titrate with 0.6476N NaOH with continuous stirring. Titrate to same light pink endpoint used to standardize solutions. Record mL of NaOH titrated.
- CaCO3 Equivalent = (75 - 2(mL NaOH titrated)) x 1.629
Adapted from Method 955.01, 16th edition of the Official Methods of Analysis, Association of Official Agricultural Chemists.