Method of test for building limes, Part 1: Determination of insoluble residue, loss on ignition, insoluble matter,silicon dioxide, ferric and aluminium oxide, calcium oxide and magnesium oxide 1973 Edition
This document outlines standardized laboratory procedures for assessing the chemical composition of building lime, including measuring insoluble residue, loss on ignition, and contents of silicon dioxide, ferric oxide, aluminium oxide, calcium oxide, and magnesium oxide. These methods are critical for ensuring the material meets specified chemical quality standards required in construction.
This document outlines standardized laboratory procedures for assessing the chemical composition of building lime, including measuring insoluble residue, loss on ignition, and contents of silicon dioxide, ferric oxide, aluminium oxide, calcium oxide, and magnesium oxide. These methods are critical for ensuring the material meets specified chemical quality standards required in construction.
Audience
Who Uses This Standard
Structural engineers
Laboratory technicians specializing in material testing
Construction quality assurance professionals
Researchers focused on construction materials
Project managers overseeing building works
Chemical analysts in the cement and lime sectors
Regulatory compliance specialists
Contents
Key Topics Covered
✓Evaluation of insoluble residue in acidic and alkaline media
✓Measurement of weight loss upon ignition
✓Chemical analysis of insoluble substances including silica
✓Quantification techniques for ferric and aluminium oxides
✓Determination of calcium oxide concentration
✓Estimation of magnesium oxide content
✓Sample conditioning and treatment protocols
✓Application of volumetric and EDTA titration methods
✓Preparation and calibration of chemical reagents
✓Filtration and ignition methodologies
✓Computation and presentation of analytical results
✓Safe handling practices for chemicals used in testing
Structure
Table of Contents
1Scope and Overview of Test Methods▼
Scope of the Standard
This section defines the laboratory procedures for analyzing building lime to quantify:
Insoluble residues in dilute acid and alkali solutions
Loss on ignition (LOI)
Insoluble residues in hydrochloric acid
Silicon dioxide (SiO₂)
Ferric oxide (Fe₂O₃) and aluminium oxide (Al₂O₃)
Calcium oxide (CaO)
Magnesium oxide (MgO)
Important Calculation
Calcium oxide equivalent (E) for potassium permanganate solution is determined as:
E = (Calcium oxide equivalent of KMnO₄ solution) / (Volume of KMnO₄ solution in ml)
Where I' denotes the volume of KMnO₄ required to titrate 0.7560 g sodium oxalate.
Additional Analytical Technique
EDTA titration method is referenced for non-hydraulic lime (IS 5949-1970) to determine Ca and Mg content volumetrically.
Notes
Results are rounded according to IS 2-1960.
Mortar preparation follows IS 2250-1981.
2Sample Handling and Preparation Procedures▼
Sample Preparation and Treatment
Prepare test samples in accordance with Clause 7.2 of IS 712-1973.
Combine filtrates as specified and dilute to 500 ml with distilled water.
From this, take a 25 ml aliquot for analysis.
Oxalate Precipitation and Titration Steps:
Take a 100 ml portion from the latter half of the filtrate.
Adjust pH to alkaline using ammonium hydroxide.
Boil the solution vigorously.
Add 35 ml of boiling saturated ammonium oxalate solution.
Stir and allow precipitate to settle.
Filter using 11 cm filter paper or Gooch/sintered crucible.
Wash the precipitate with hot water up to ten times, not exceeding 125 ml.
Transfer the filter paper and precipitate to a beaker and wash the precipitate off the paper.
Add 50 ml of dilute sulfuric acid and dilute to 250 ml with hot water.
Heat the mixture to 80–90°C.
Titrate with standard potassium permanganate to a pink endpoint.
Introduce the folded filter paper into the titration flask; the pink coloration disappears.
Continue titration dropwise until the pink endpoint reappears.
Summary Table of Important Volumes:
Step
Volume/Quantity
Dilution volume of filtrate
500 ml
Aliquot for analysis
25 ml
Aliquot for oxalate process
100 ml
Saturated ammonium oxalate
35 ml (hot)
Washing volume
≤125 ml hot water
Dilute sulfuric acid
50 ml
Volume before titration
250 ml
3Assessment of Insoluble Residue Including Silicon Dioxide Using Hydrochloric Acid▼
Procedure to Determine Insoluble Residue and Silicon Dioxide (SiO₂) in Hydrochloric Acid
Use distilled water conforming to IS 1070-1960t for reagent preparation.
Weigh sample as per Clause 5.2.1.
Treat sample with hydrochloric acid to dissolve soluble components.
Filter and wash the residue thoroughly.
Dry and weigh the insoluble residue, which includes silicon dioxide.
Calculation:
Insoluble residue percentage = (Mass of dried residue / Mass of sample) × 100
Additional specific techniques to isolate SiO₂, such as treatment with hydrofluoric acid, may be applied but are beyond the scope here.
4Measurement of Loss on Ignition (LOI)▼
Loss on Ignition Determination Method
Weigh 1 g of the prepared sample into a platinum crucible with a lid.
Ignite at a temperature of at least 1000°C until the mass remains constant.
Calculation:
LOI (%) = 100 × (Initial mass - Mass after ignition) / Initial mass
Express the insoluble residue results on an ignited mass basis.
This procedure quantifies the volatile matter lost upon heating, essential for characterizing lime.
5Quantification of Insoluble Matter Including Silicon Dioxide▼
This section describes how to measure insoluble constituents including silicon dioxide:
Express insoluble matter as a percentage by mass relative to the original sample.
Calculate Loss on Ignition (LOI) using:
LOI (%) = 100 × (Mass before ignition - Mass after ignition) / Mass before ignition
After acid digestion and filtration, dry and weigh the residue.
Calculate insoluble matter percentage as:
(Mass of residue / Mass of original sample) × 100
This ensures precise quantification of residues that do not dissolve during acid treatment.
6Silicon Dioxide Content Determination▼
The method to quantify silicon dioxide involves:
Measuring the mass of the original sample (mₛ).
Measuring the mass after chemical treatment (mᵣ).
Calculating the mass of SiO₂ as mₛ - mᵣ.
Expressing silicon dioxide as a percentage:
% SiO₂ = (Mass of SiO₂ / Mass of original sample) × 100
This approach provides accurate measurement of silica content in building lime.
7Evaluation of Ferric and Aluminium Oxides▼
Key points for determining ferric and aluminium oxides:
Ferric oxide (Fe₂O₃) is measured by precipitating and igniting the sample at 1100°C in a platinum crucible to constant weight.
The combined mass of ferric and aluminium oxides is obtained by ignition of the precipitate.
Aluminium oxide (Al₂O₃) content is calculated by subtracting ferric oxide mass from the total combined oxides.
Note: Minor amounts of other oxides such as P₂O₅, Mn₃O₄, and TiO₂ may be present in some limes.
8Determining Calcium Oxide Concentration▼
Procedure highlights for calcium oxide determination:
Report CaO content as a percentage of the sample mass.
After precipitation, filter and wash the residue with 0.1% ammonium oxalate.
Ignite the residue in a weighed platinum crucible to constant mass.
The difference in mass corresponds to the CaO content.
Titration equivalence: 1 mL of standard potassium permanganate solution corresponds approximately to 0.005 g of CaO.
Calculation formula:
CaO (%) = (Mass of CaO / Mass of sample) × 100
9Magnesium Oxide Determination Method▼
Magnesium oxide (MgO) content is calculated using the formula:
MgO (%) = (A / B) × 36.2
Where:
A = Mass of magnesium pyrophosphate obtained after ignition.
B = Mass of the ignited sample aliquot used for calcium oxide estimation.
For non-hydraulic lime, the EDTA titration method (IS 5949-1970) applies.
This method follows calcium oxide determination and corrects aluminium oxide content by subtracting ferric oxide.
10Reporting and Presentation of Test Results▼
Guidelines for reporting test outcomes:
Express all oxide contents as a percentage by mass of the sample taken (Clause 5.2.1).
Ferric and aluminium oxides are reported as combined or individual percentages.
Calcium oxide content is presented as a percentage by sample mass.
Magnesium oxide content is computed using the specific formula involving magnesium pyrophosphate mass.
This ensures consistent and clear documentation of chemical composition results.
Frequently Asked
Popular Questions About IS 6932 PART 1
?What is the procedure outlined in IS 6932 Part 1 for determining insoluble residue in building lime?▼
IS 6932 Part 1 (1973) details a process for measuring insoluble residue in building lime involving several steps: first, the lime sample is filtered to collect the residue on filter paper. Then, the residue is digested with sodium carbonate solution for about 30 minutes just below boiling, with hot water added to compensate for evaporation. After decanting and washing, a second digestion for approximately 10 minutes is performed, followed by further filtration and washing with sodium carbonate solution and hot water until alkali-free. Finally, the residue is washed with dilute hydrochloric acid and rinsed with hot water until chloride-free. This method isolates insoluble impurities essential for quality evaluation.
?How is loss on ignition determined according to IS 6932 Part 1?▼
According to IS 6932 Part 1, loss on ignition is measured by weighing 1 gram of the prepared lime sample in a platinum crucible with a lid, then igniting it at a temperature of at least 1000°C until the mass remains constant. The loss on ignition percentage is calculated by the formula: LOI (%) = ((Initial mass - Mass after ignition) / Initial mass) × 100. The result represents the volatile components lost during heating and is reported as a percentage of the original sample mass.
?Which chemical reagents and solutions are specified for testing ferric and aluminium oxides in IS 6932 Part 1?▼
The standard specifies several reagents for analyzing ferric and aluminium oxides: sodium pyrosulphate (3–4 g) is used for low-temperature fusion of the combined oxides in a platinum crucible. Dilute sulfuric acid is added post-fusion to ensure at least 5 g of absolute acid for dissolving the melt. Water aids in dissolution during heating. Hydrofluoric acid and sulfuric acid are used to volatilize silicon dioxide precipitates for correction purposes. The precipitate is ignited at 1100°C in a platinum crucible to obtain constant weight, enabling accurate quantification of ferric and aluminium oxides.
?What methods does IS 6932 Part 1 recommend for quantifying calcium oxide and magnesium oxide content?▼
IS 6932 Part 1 recommends the following methods: For calcium oxide, a gravimetric approach involves filtering and washing the precipitate with 0.1% ammonium oxalate, followed by ignition in a platinum crucible to constant mass; the mass difference corresponds to CaO content. For non-hydraulic lime, an EDTA complexometric titration (per IS 5949-1970) may be used. Magnesium oxide content is calculated gravimetrically using the mass of magnesium pyrophosphate obtained after ignition divided by the ignited sample mass aliquot, multiplied by 36.2.
?How should test results be calculated and reported in accordance with IS 6932 Part 1?▼
Results must be expressed as a percentage by mass of the test sample taken, per Clause 5.2.1. Ferric and aluminium oxides are reported individually or combined, calcium oxide content is reported as a percentage by mass, and magnesium oxide is calculated using the formula involving the mass of magnesium pyrophosphate divided by the mass of the ignited sample aliquot times 36.2. All results should be clearly documented with reference to the test methods and sample details to ensure traceability and uniformity.
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