Method of test for building limes Determination of residue on slaking of quicklime

IS 6932 Part 3 - Scope & Key Specifications Summary

Scope:
This standard specifies requirements and test methods for building limes (third revision).

Key Specifications & Notes:

• Water Quality: Use distilled water as per IS:1070-1960 for all reagent purposes (Clause 2.2).
• Test Reporting:
  • Residues on sieves reported as % mass of quicklime used (Clause 2.5).
  • Follow IS:2-1960 for rounding off numerical test results (Clause 0.3).
• Isothermal Slaking & Putty Preparation: Refer to Table 2.3 (Clause 2.5) for standard procedures.

Important References:

Contact & Offices (for standards & clarifications):

• Headquarters: Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi - 110002
• Regional Offices: Delhi, Calcutta, Chandigarh, Madras, Bombay
• Branch Offices: Ahmedabad, Bangalore, Bhopal, Bhubaneshwar, Guwahati, Hyderabad, Jaipur, Kanpur, Patna, Trivandrum, Nagpur, Pune

If you need detailed tables or formulas for lime testing procedures, please specify the test type (e.g., slaking time, fineness, purity).

IS 6932 Part 3: Preparation of Sample - Key Points

1. Sample Preparation

   • As per Clause 2.1, sample preparation must follow Clause 7.2 of IS 712:1973 (Quicklime specification).
   • This involves selecting representative quicklime, drying, and sieving to ensure uniformity.

2. Isothermal Slaking and Putty Preparation

   • Clause 2.3 & Table 2.3 (Clause 2.5) detail the process of isothermal slaking:
     • Quicklime is slaked under controlled temperature to produce putty.
     • Slaking time and temperature are controlled to ensure complete hydration.

3. Reporting Test Results

   • Residue on sieves is reported as percentage by mass of quicklime used.
   • Follow rounding off rules as per IS 2:1960.

Summary Table: Isothermal Slaking (from Table 2.3)

Notes:

• Refer to IS 712:1973 Clause 7.2 for exact sample prep steps (drying, crushing, sieving).
• Ensure consistent sample size and moisture content.
• Accurate residue measurement critical for quality control.

flowchart TD
    A[Quicklime Sample] --> B[Drying & Crushing]
    B --> C[Sieving as per IS 712]
    C --> D[Isothermal Slaking]
    D --> E[Putty Preparation]
    E --> F[Sieving & Residue Measurement]
    F --> G[Report % Residue by Mass]

This process ensures reliable and standardized testing of quicklime samples per IS 6932 Part 3.

IS 6932 Part 3: Isothermal Slaking of Sample and Preparation of Putty

Key Specifications & Procedure

• Sample Preparation:

  • Sieve quicklime through 2.36 mm IS sieve (IS:460-1962).
  • Break residue gently and resieve until all passes 2.36 mm sieve.

• Water Quantity for Slaking:

  • Use 4 times the mass of quicklime (by weight) for most limes.
  • For high calcium limes, use up to 8 times the mass.

• Slaking Temperature & Duration:

  • If specified by vendor, maintain water temperature within ±2°C of specified value.
  • If not specified, perform two slakings:
    • At 50°C
    • At 100 ± 2°C
  • Add 5 kg crushed quicklime gradually over ≥5 minutes.
  • Stir constantly and maintain temperature for 1 hour.
  • Let stand for 24 hours, stirring twice (last stirring within 1 hour before end).

• Sieving After Slaking:

  • Sieve supernatant liquid and residue through 850-micron and then 300-micron IS sieves.
  • Use a washed unbleached calico cloth as temporary filter.
  • Wash residues without rubbing.
  • Dry residue at 100 ± 10°C to constant mass.
  • Weigh residues separately on each sieve.

Summary Table

flowchart TD
    A[Crushed Quicklime] --> B[Sieve 2.36 mm]
    B --> C[Slaking Vessel with Water (4x mass)]
    C --> D{Temperature Control}

IS 6932 Part 3: Procedure for Slaking and Sieving Quicklime

Key Specifications & Procedure:

• Sample Preparation:

  • Sieve quicklime through 2.36 mm IS sieve (IS:460-1962).
  • Break residue gently to avoid fines; resieve until all passes 2.36 mm.

• Slaking:

  • Use 4 times the mass of water for most limes; up to 8 times for high calcium limes.
  • Maintain water temperature within ±2°C of specified temperature (usually 50°C or 100±2°C).
  • Add 5 kg crushed lime gradually over ≥5 minutes with constant stirring.
  • Control temperature during 1-hour slaking; spray additional water carefully if needed.
  • Let stand 24 hours, stirring twice (last within 1 hour before end).

• Sieving:

  • After 24 hrs, stir thoroughly, then sieve:
    • First through 850-micron IS sieve
    • Then through 300-micron IS sieve
  • Use a temporary filter cloth (unbleached calico, 1.0 x 1.5 m).
  • Wash residues gently with water jet (no rubbing).
  • Dry residues at 100 ±10°C to constant mass.
  • Weigh residues separately.

Summary Table of Key Parameters:

Flowchart of Procedure:

flowchart TD
    A[Crush & Sieve lime through 2.36 mm] --> B[Slake lime in hot water (4-8x water)]
    B --> C

IS 6932 Part 3: Drying and Weighing of Residue on Slaking of Quicklime

Key Specifications & Procedure (Clause 2.4)

• Sample: Use product after 24 hours of slaking.
• Sieving:
  • First, sieve the supernatant liquid.
  • Then sieve remainder after stirring through:
    • 850-micron IS Sieve
    • 300-micron IS Sieve
• Use a vessel similar to slaking vessel fitted with a temporary filter cloth (close woven unbleached calico, ~1.0 x 1.5 m, washed free from dressing).
• Transfer entire slaked material onto sieves by washing with a water jet.
• Wash residues on sieves gently with a flexible water jet (operation ≤ 30 minutes).
• Do not rub residue through sieves.

Drying & Weighing

• Dry residue at 100 ±10 °C until constant mass.
• Weigh residues separately for each sieve.

Summary Table

This method ensures accurate quantification of insoluble residue after quicklime slaking, critical for quality control.

IS 6932 Part 3: Calculation and Reporting of Test Results

Key Points:

• Rounding Off: Final observed or calculated values must be rounded according to IS 2-1960 (Rules for rounding off numerical values).

• Reporting Residues: Residues on sieves after slaking quicklime are reported as percentage of the mass of quicklime taken.

Reporting Formula:

[ \text{Residue (%)} = \frac{\text{Mass of residue on sieve}}{\text{Mass of quicklime sample}} \times 100 ]

• Report each sieve residue as a percentage.
• Ensure consistent units (mass in grams or kilograms).

Additional Notes:

• The test results must be clearly tabulated with sieve sizes and corresponding residue percentages.
• Use proper significant figures as per IS 2-1960.
• Maintain traceability by documenting sample details and test conditions.

Summary Table Example:

flowchart TD
    A[Quicklime Sample] --> B[Slaking Process]
    B --> C[Sieving]
    C --> D[Residue Mass on Each Sieve]
    D --> E[Calculate % Residue]
    E --> F[Report Results as % of Original Sample]

References:

• IS 6932 Part 3 (1993)
• IS 2-1960 (Rounding off rules)

IS 6932 Part 3 (1973) — Equipment and Materials: Key Points

1. Materials Specification

• Quicklime: Should conform to IS: 6932 Part 3.
• Water: Use distilled water as per IS: 1070-1960 for reagent purposes.

2. Test Sample Preparation

• Isothermal Slaking (Clause 2.5): Residues on sieves reported as % mass of quicklime used.
• Follow IS: 2-1960 for rounding off numerical test results.

3. Reporting Test Results

• Residue percentage =
  [ \text{Residue %} = \frac{\text{Mass of residue on sieve}}{\text{Mass of quicklime taken}} \times 100 ]

4. Contact & Reference

• Manak Bhavan, New Delhi is the headquarters for standards.
• Regional offices available for technical support.

Summary Table: Materials & Equipment

flowchart TD
    A[Quicklime Sample] --> B[Isothermal Slaking]
    B --> C[Sieving]
    C --> D[Residue % Calculation]
    D --> E[Report Result (IS 2-1960 rounding)]

This concise framework ensures compliance with IS 6932 Part 3 for equipment and materials in lime testing.

IS 6932 Part 3 (1973) - Precision and Accuracy Key Points

The code does not explicitly provide formulas or tables for precision and accuracy. However, relevant guidelines include:

• Rounding Off Results:
  As per Clause 0.3, final test values must be rounded according to IS 2:1960 (Rules for rounding off numerical values).

• Reporting Test Results (Clause 2.5):
  Residues on sieves are reported as percentage of mass of quicklime taken, ensuring consistent accuracy in reporting.

• Use of Distilled Water:
  Clause 2.2 specifies using distilled water conforming to IS 1070:1960 to maintain reagent purity and test accuracy.

Additional Engineering Notes on Precision and Accuracy in Testing:

• Precision refers to repeatability of test results under unchanged conditions.
• Accuracy refers to closeness of test results to the true value.

Common Practice for Precision & Accuracy:

Rounding Off (IS 2:1960) Summary:

flowchart TD
    A[Test Measurement] --> B[Calculate Mean]
    B --> C[Calculate Std Deviation]
    C --> D{Is Accuracy Acceptable?}
    D -- Yes --> E[Report Results (Rounded per IS 2)]
    D -- No --> F[Re-test or Calibrate]

For detailed precision/accuracy procedures, refer to relevant testing standards or statistical methods alongside IS 6932 Part 3.

IS 6932 Part 3 References to Other Standards: Key Points

• Rounding Off Results:
  Follow IS 2:1960 for rounding off numerical values in test reports or calculations to maintain consistency.

• Updated Standards Reference:
  Replace old references with current standards, e.g.,

  • Use IS 460 (Part 1): 1985 instead of IS 460:1962 for relevant material specifications.

• Material Specifications:
  Building limes must comply with the latest specification (third revision), as noted in the footnote.

Summary Table of Relevant Standards

Note: IS 6932 Part 3 (1973) primarily cross-references these standards for consistency in testing and reporting.

flowchart LR
    A[IS 6932 Part 3] --> B[IS 2:1960 (Rounding)]
    A --> C[IS 460 (Part 1): 1985 (Materials)]
    A --> D[Building Limes Spec (3rd Rev.)]