106.3.2.26 TM-26, Determination of Calcium Carbonate and Magnesium Carbonate in Lime and Pigment Materials: Difference between revisions

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This method determines the percent chlorine in chlorinated rubber and chlorinated paraffin used in traffic paint vehicle.
This method determines the percent calcium carbonate and percent magnesium carbonate in Agricultural Lime and calcium carbonate paint pigments.


==106.3.2.25.1 Reagents and Apparatus==
==106.3.2.26.1 Reagents and Apparatus==


(a) Parr Peroxide Bomb Apparatus, 22 mL, flame ignition Macro Bomb, including ignition shield.
(a) Sargent - Malmstadt Automatic Spectro-Electro titrator, Model S-29700


(b) Sodium Peroxide (Na<sub>2</sub>O<sub>2</sub>), Reagent Grade, granular, low chloride.
(b) Hexaver Solution
::Dissolve 65 g Hexaver (Disodium Dihydrogen 1, 2, Cyclohexanediaminetetracetate) in 2.0 liters of H<sub>2</sub>O


(c) Nitric Acid (HNO<sub>3</sub>), Reagent Grade.
(c) Magnesium Chloride Solution
::Dissolve 8.00 g MgCl<sub>3</sub><sup>.</sup>6H2O Reagent Grade) in H<sub>2</sub>O and dilute to 1 liter


(d) Silver Nitrate (AgNO<sub>3</sub>), Reagent Grade.
(d) Calcon Indicator
::Dissolve 0.30 g Calcon in 50 ml of Methanol


(e) Sodium Chloride (NaCl), Reagent Grade, dried at 105-110°C for 1 hour prior to use.
(e) EBT Indicator
::Dissolve 0.30 g of Erichrome Black T in 50 ml of Methanol


(f) Millivolt Meter equipped with a Combination Chloride Electrode.
(f) Potassium Hydroxide Solution
::Dissolve 100 g KOH (Reagent Grade) in 200 ml H<sub>2</sub>O


==106.3.2.25.2 Preparation of Standard Solutions==
==106.3.2.26.2 Standardization of Hexaver Solution==
(a) Weigh 0.5801 g Calcium Carbonate (Primary Standard Grade) and transfer to a 500 ml volumetric flask. Slowly add 15 ml HCl (Sp.Gr. 1.19), and boil for a few minutes to expel CO<sub>2</sub>. Add 2 g NH<sub>4</sub>Cl (Reagent Grade) and 200 ml H<sub>2</sub>O. Add with a pipette 10.00 ml of the MgCl<sub>2</sub> solution, and make alkaline to methyl red with NH<sub>4</sub>0H (Sp.Gr. 0.90). Cool to room temperature and dilute to volume.


(a) Standard Sodium Chloride Solution (0.0100N) - Weigh 0.5844 g dried NaCl,
(b) Turn on the power switch of the automatic titrator and allow to warm up for about
Reagent Grade, dissolve in water and dilute to 1L.
15 minutes. Set the controls as follows:


(b) Standard Silver Nitrate Solution (0.01N) - Weigh 1.699 g AgNO<sub>3</sub>, Reagent Grade, dissolve in water and dilute to 1L. Standardize against 0.0100 N NaCl.
::Function Switch - Spectro
::Polarity Switch - No. 2
::Wavelength Selector - 650
::The Hupp Cadmium Sulfide photocell should be used.


==106.3.2.25.3 Procedure==
Pipette 25.00 ml aliquots into two 100 ml tall form beakers. To one beaker add 3 ml KOH Solution, 10 ml H<sub>2</sub>O, and 10 drops of Calcon indicator. Place the beaker on the titration platform and start the titrator. The burette should be adjusted so that the rate of delivery is about 45 seconds between the 35 ml mark and the 45 ml mark. When the
titrator shuts off, record the burette reading as Tca. To the second beaker, add 10 ml
NH<sub>4</sub>OH and 8 drops of EBT Indicator. Titrate as described above, and record the burette reading as Tmg.


(a) Weigh, to the nearest 0.1 mg., 0.40 g sample for Chlorinated Paraffin or 0.30 g sample for Chlorinated Rubber and transfer to a Parr Bomb cup which contains 15 g Na<sub>2</sub>O<sub>2</sub>. Thoroughly mix the contents of the fusion cup with a stirring rod, wipe the rod with a small piece of filter paper and place the paper in the cup. Place the bomb assembly in the protective shield and fire strongly with a Bunsen burner for 20 minutes. Cool to room temperature and disassemble.
Calculate the Calcium and Magnesium equivalents of the Hexaver as follows:


NOTE: If difficulties arise in obtaining complete combustion of Chlorinated
::CaO Equiv. (F<sub>ca</sub>) = 65 / T<sub>ca</sub>
Paraffin samples, small amounts of powdered sucrose or powdered NaNO<sub>3</sub> may be mixed with the Na<sub>2</sub>O<sub>2</sub> and sample the fusion cup prior to ignition. However, the total combustible matter should not exceed 0.5 g.


Rinse the bomb cover into a 600-mL beaker with about 150 mL of water, place the cup on its side in the beaker, cover with a watch glass and warm gently until solution of the fused material is complete. Remove the cup and rinse well with water. Add HNO<sub>3</sub> in small increments until the solution is acid to methyl orange. Add 5 mL HNO<sub>3</sub> in excess and warm gently until solution is complete. Filter through a coarse paper into a 1000-mL volumetric flask, washing well with hot water. Allow to cool to room temperature and dilute to volume with water.
::MgO Equiv. (F<sub>mg</sub>) = F<sub>ca</sub> / 1.391


(b) Transfer a 50-mL aliquot to a 250-mL beaker and determine percent chlorine by
::K = T<sub>mg</sub> - T<sub>ca</sub>
potentiometric titration.


(c) Perform a blank determination following the procedure given in (a) and (b) above,
==106.3.2.26.3 Procedure==
omitting only the addition of sample.
Weigh 0.5000 g sample of the material and transfer to a 250 ml beaker. Moisten with H<sub>2</sub>O and add 10 ml HCL. Remove the insoluble matter, Si0<sub>2</sub>, and R<sub>2</sub>O<sub>3</sub> by the methods set forth in ASTM C25. Collect all the filtrates and washings from the R<sub>2</sub>O<sub>3</sub> filtration in a 500 ml volumetric flask. Pipette 10 ml MgCl<sub>2</sub> solution into the flask, cool and dilute to volume.
Tritrate 25 ml aliquots for calcium and magnesium as described above in Section 3. Record the burette readings as T<sub>ca</sub> and T<sub>mg</sub>.


==106.3.2.25.4 Calculation and Report==
==106.3.2.26.4 Calculations==


Report percent chlorine to the nearest 0.1% as follows:
Calculate the percent Calcium Carbonate and percent Magnesium Carbonate as follows:


::% Chlorine (Cl) =<math>100 \times \frac {(A - B) \times C \times 0.709}{D} </math>
:% CaCO<sub>3</sub> = F<sub>ca</sub> x T<sub>ca</sub> x 1.7848


Where:
:% MgCO<sub>3</sub> = F<sub>mg</sub> x (T<sub>mg</sub> - T<sub>ca</sub> - K) x 2.0915
:A = milliliters of AgNO<sub>3</sub> solution to titrate sample,
 
:B = milliliters of AgNO<sub>3</sub> solution to titrate blank,
Report the results, to the nearest 0.1 percent, as follows:
:C = normality of AgNO<sub>3</sub> solution,
 
:D = grams of the sample.
:% Calcium Carbonate CaCO<sub>3</sub>)
 
:% Magnesium Carbonate (MgCO<sub>3</sub>)




[[Category:106.3.2 Material Inspection Test Methods]]
[[Category:106.3.2 Material Inspection Test Methods]]

Latest revision as of 12:49, 30 June 2010

This method determines the percent calcium carbonate and percent magnesium carbonate in Agricultural Lime and calcium carbonate paint pigments.

106.3.2.26.1 Reagents and Apparatus

(a) Sargent - Malmstadt Automatic Spectro-Electro titrator, Model S-29700

(b) Hexaver Solution

Dissolve 65 g Hexaver (Disodium Dihydrogen 1, 2, Cyclohexanediaminetetracetate) in 2.0 liters of H2O

(c) Magnesium Chloride Solution

Dissolve 8.00 g MgCl3.6H2O Reagent Grade) in H2O and dilute to 1 liter

(d) Calcon Indicator

Dissolve 0.30 g Calcon in 50 ml of Methanol

(e) EBT Indicator

Dissolve 0.30 g of Erichrome Black T in 50 ml of Methanol

(f) Potassium Hydroxide Solution

Dissolve 100 g KOH (Reagent Grade) in 200 ml H2O

106.3.2.26.2 Standardization of Hexaver Solution

(a) Weigh 0.5801 g Calcium Carbonate (Primary Standard Grade) and transfer to a 500 ml volumetric flask. Slowly add 15 ml HCl (Sp.Gr. 1.19), and boil for a few minutes to expel CO2. Add 2 g NH4Cl (Reagent Grade) and 200 ml H2O. Add with a pipette 10.00 ml of the MgCl2 solution, and make alkaline to methyl red with NH40H (Sp.Gr. 0.90). Cool to room temperature and dilute to volume.

(b) Turn on the power switch of the automatic titrator and allow to warm up for about 15 minutes. Set the controls as follows:

Function Switch - Spectro
Polarity Switch - No. 2
Wavelength Selector - 650
The Hupp Cadmium Sulfide photocell should be used.

Pipette 25.00 ml aliquots into two 100 ml tall form beakers. To one beaker add 3 ml KOH Solution, 10 ml H2O, and 10 drops of Calcon indicator. Place the beaker on the titration platform and start the titrator. The burette should be adjusted so that the rate of delivery is about 45 seconds between the 35 ml mark and the 45 ml mark. When the titrator shuts off, record the burette reading as Tca. To the second beaker, add 10 ml NH4OH and 8 drops of EBT Indicator. Titrate as described above, and record the burette reading as Tmg.

Calculate the Calcium and Magnesium equivalents of the Hexaver as follows:

CaO Equiv. (Fca) = 65 / Tca
MgO Equiv. (Fmg) = Fca / 1.391
K = Tmg - Tca

106.3.2.26.3 Procedure

Weigh 0.5000 g sample of the material and transfer to a 250 ml beaker. Moisten with H2O and add 10 ml HCL. Remove the insoluble matter, Si02, and R2O3 by the methods set forth in ASTM C25. Collect all the filtrates and washings from the R2O3 filtration in a 500 ml volumetric flask. Pipette 10 ml MgCl2 solution into the flask, cool and dilute to volume. Tritrate 25 ml aliquots for calcium and magnesium as described above in Section 3. Record the burette readings as Tca and Tmg.

106.3.2.26.4 Calculations

Calculate the percent Calcium Carbonate and percent Magnesium Carbonate as follows:

% CaCO3 = Fca x Tca x 1.7848
% MgCO3 = Fmg x (Tmg - Tca - K) x 2.0915

Report the results, to the nearest 0.1 percent, as follows:

% Calcium Carbonate CaCO3)
% Magnesium Carbonate (MgCO3)
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