Total Hardness [Table

The hardness of water or mud filtrate is due primarily to the presence of calcium (Ca++) and magnesium (Mg++) ions. The harder the water, the more difficult for many chemicals to function, particularly bentonite clay. Also, hardness decreases efficiency of most polymers.

Hardness analysis is a titration of divalent cations in a filtrate using EDTA reagent with an indicator that changes from wine-red to blue at the endpoint. The endpoint will be gray-blue in dark-colored filtrates.

Step

  1. Add 50 cm3 deionized water to titration vessel; then, add 2 cm3 (20 drops) of Versenate Hardness Buffer Solution.
  2. Add 10 drops of Versenate Hardness Indicator solution. If calcium and/or magnesium is present in the deionized water, a wine-red color will develop. If not, the solution will remain blue.
  3. While stirring, titrate with EDTA (standard versenate) until solution color changes from wine-red to blue. DO NOT GO PAST ENDPOINT!

^Note: Steps 1-3 have removed the hardness from the deionized water if any was present. J

  1. Add 1 cm3 of filtrate to the deionized water. If calcium and/or magnesium is present, a wine-red color will develop. While stirring, titrate (drop by drop) with EDTA until color indicator changes from wine-red to blue.
  2. Note the cm3 of EDTA and calculate hardness, mg/L, as follows:

cm3 of filtrate

r N

Table 6

Total Hardness Titration Chart

Total Hardness

Chemical Tests

Column 1

Column 2

Sample

None

1 cm3 filtrate

Deionized Water

50 cm3

None

Buffer

2 cm3 Versenate Hardness Buffer

None

Color Indicator

10 drops Versenate Hardness Indicator

None

(Standard Versenate)

Color Change

Wine Red to Blue Do not go past endpoint!

Wine Red to Blue

Record

None

(cm3 of EDTA)(400-cm3 Filtrate

Note:

V

Proceed to Col. 2

J

Calcium and Magnesium [Table 7]

As mentioned under Total Hardness, divalent cations can adversely affect mud properties. Calcium and Magnesium can affect muds in different ways, therefore, they may need to be analyzed separately.

Calcium analysis is a titration of a filtrate using EDTA reagent, plus a high pH buffer so that the magnesium ions are precipitated and only calcium ion is being analyzed.

r

Table 7

Calcium/Magnesium Hardness Titration Chart

Chemical Tests

Calcium

Magnesium (Mg++)

Column 1

Column 2

Sample

None

1 cm3 filtrate

None

Deionized Water

50 cm3

None

None

Buffer

1 cm3 Versenate Calcium Hardness Buffer

None

None

Color Indicator

Pinch of Calver II Indicator Powder

None

None

(Standard Versenate)

None

Color Change

Wine Red to Blue Do not go past endpoint!

Wine Red to Blue

None

Record

None

(cm3 of EDTA)(400) cm3 Filtrate

Total Hardness -Calcium x 243

Note:

V

Proceed to Col. 2

This calculation is based on recorded results from Total Hardness and Calcium tests.

  1. Add 50 cm3 deionized water to titration vessel, then add 1 cm3 Calcium Hardness Buffer solution.
  2. Add a pinch of Calver II indicator powder. If calcium is present, a wine-red color will develop.
  3. While stirring, titrate with EDTA (drop by drop) until sample color changes from wine-red to blue. DO NOT GO PAST ENDPOINT!
  4. Add 1 cm3 of filtrate to the deionized water. If calcium is present, a wine-red color will develop. While stirring, titrate with EDTA (drop by drop) until the color indicator changes from wine-red to blue.
  5. Note the cm3 of EDTA and calculate calcium, mg/L, as follows:

cm3 of filtrate

6. The magnesium ion concentration is determined by difference of the total hardness less the calcium, times a factor of (0.6).

Magnesium, mg/L = [(Total Hardness, mg/L) - (Calcium, mg/L)] (0.6)

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Responses

  • Ivone
    How to treat total hardness from drilling mud?
    1 year ago
  • Petri
    How can i bring hardness fluid down?
    11 months ago
  • lauri
    What do you tritrate hardness with in water base mud?
    9 months ago
  • venla
    How to run hardness test with water hardness buffer?
    8 months ago
  • Ralph
    What do you titrate hardness with?
    4 months ago
  • bertha
    How hardness of water affects performance of drilling fluids?
    4 months ago
  • lotta
    How drill hardness affects drilling efficiency?
    1 month ago

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