Work Instruction Code: QOP-QUL -0102-05
Date of
Department: Quality Insoluble Residue Issue: 1-Oct-10
1. Objective
This test method covers the determination of the insoluble residue once
using hydrochloric acid and sodium carbonate and once using hydrochloric
acid and potassium hydroxide according to the specifications of EN 196-
2:1992.
2. Analyzed Material
This test is performed on the cement mainly.
3. References
pr EN 196-2: 1992
4. Specifications
EN 196-7
]
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Work Instruction Code: QOP-QUL -0102-05
Date of
Department: Quality Insoluble Residue Issue: 1-Oct-10
5. Definitions
• The method using sodium carbonate is a
conventional method in which the insoluble
residue in cements is obtained by treatment with
a dilute hydrochloric acid solution so as to
avoid as far as possible the precipitation of
soluble silica. The residue from this treatment is
treated with a boiling solution of sodium
carbonate in order to re-dissolve traces of silica
which may have been precipitated . The residue
is determined gravimetrically after ignition.
• The method using potassium hydroxide in
which the insoluble residue in cements is
obtained by treating with a hydrochloric acid
solution. The residue form this treatment is
then treated with a boiling solution of potassium
hydroxide. The residue is determined
gravimetrically after ignition.
6. Apparatus
• Sensitive Balance (accuracy to 0.0001g)
• Platinum crucible (20-25ml capacity)
• Electric Furnace (975C ± 25)
• Medium Filter Paper
• Desicator
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Work Instruction Code: QOP-QUL -0102-05
Date of
Department: Quality Insoluble Residue Issue: 1-Oct-10
7. Reagents
1. Hydrochloric acid (1.18 to 1.19 g/cm3 at 20C),
(1+3), (1+9), (1+19)
2. Silver Nitrate
3. Sodium Carbonate solution
4. Potassium hydroxide solution
8. Safety
PPE' S must be wearing
• Safety goggles
• Gloves
• Safety shoes
9. Procedure
I - Determination using hydrochloric acid and sodium carbonate
• Add 90ml of hot water to 1 ± 0.05 of cement (w1),placed in a 250ml
beaker while stirring the mixture vigorously, add 10 ml of
concentrated and hydrochloric acid
• Heat the solution gently and crush the sample with the flattened
end of a glass stirring rod until decomposition of the cement is
complete.
• Allow the solution to digest for 15min. at a temperature just below
boiling.
• Filter the residue through a medium filter paper and wash
thoroughly with almost boiling water.
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Work Instruction Code: QOP-QUL -0102-05
Date of
Department: Quality Insoluble Residue Issue: 1-Oct-10
• Transfer the filter paper and its contents back to the reaction
beaker and add 100ml of the sodium bicarbonate.
• Boil for 15min.
• Filter on a medium filter paper and wash with almost boiling
water, then four times with hot hydrochloric acid (1+19) until pH <
2, and finally at least 10 times with almost boiling water until free
from Cl- ions, tested by silver nitrate test.
Ignite at 975 ± 25C, and then check for constant mass. (An ignited
period of 30min. is sufficient for obtaining constant mass (w2).
II - Determination using hydrochloric acid and potassium hydroxide
• 25ml of cold water to 1 ± 0.05 gm of cement (w1) placed in a
porcelain dish and disperse using a glass stirring rod.
• Add 40ml of concentrated HCl.
• Heat the solution gently and crush the sample with the flattened end
of a glass stirring rod until the decomposition of the cement is
complete
• Evaporate to dryness on a water bath. Repeat the operation twice
more with 20ml concentrated HCl.
• Treat the residue form the last evaporation with 100ml of dilute HCl
(1+3).
• Re-heat, filter through a medium filter paper and wash with boiling
water at least ten times until free from Cl- ions, tested by the silver
nitrate test.
• Transfer the filter and its contents to a 250ml conical flask fitted with
a bulb condenser and add 100ml of potassium hydroxide solution.
• Leave to stand for 16hrs at room temperature and then boil the
solution under reflux for 4hrs.
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Work Instruction Code: QOP-QUL -0102-05
Date of
Department: Quality Insoluble Residue Issue: 1-Oct-10
• Filter on a medium filter paper and wash with water then with 100ml
of HCl (1+9) and finally with almost boiling water until free from Cl-
ions, tested by the silver nitrate test.
• Ignite at 975 ± 25C then check for constant mass. (an ignition period
of 30min. is sufficient for obtaining constant mass)
10. Calculation
I. The insoluble residue is calculated from the formula:
Insoluble residue = w2/w1 *100 (in %)
Where w1 is the mass of the test portion
W2 is the mass of the ignited insoluble residue.
II. The insoluble residue is calculated form the formula;
Insoluble residue = w2/w1 * 100 (in %)
Where w1 is the mass of the test portion
W2 is the mass of the ignited insoluble residue
11. Experimental hints
I. Using sodium Carbonate
• The standard deviation for repeatability is
0.04%
• The standard deviation for reproducibility is
0.06%
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Work Instruction Code: QOP-QUL -0102-05
Date of
Department: Quality Insoluble Residue Issue: 1-Oct-10
• If a cloudy filtrate is observed, filter again on a
fine filter paper, wash thoroughly with hot
water and combine the two residues on their
filter papers to ignite them.
II. Using potassium hydroxide
• The standard deviation for repeatability is
0.15%
• The standard deviation for reproducibility is
0.18%
12. Responsibilities
Who is responsible to do the test: Chemist
Reports to whom: Team Leader
Who takes the action: Team Leader
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