Method of test for building limes Determination of un hydrated oxide, Part v: Determination of un hydrated oxide

IS 6932 Part 5 - Scope & Key Calculation Formulas

Scope (Summary)

• Methods of tests for building limes.
• Applies to chemical analysis and physical testing.
• Uses distilled/reagent grade water as per IS 1070:1992.
• Covers calculation methods for lime components.

Key Calculation Steps (Clause 3.6.2.5)

Notes:

• Use distilled water as reagent (IS 1070:1992).
• Rounding off values per IS 2-1960.
• Chemical conversions rely on molecular weight ratios.

flowchart TD
    A[Loss on Ignition] -->|Subtract CO₂| B[Combined Water (X)]
    B -->|Subtract Water equiv. of CaO (Y)| C[Remaining Water (Z)]
    CO2 -->|×1.275| CaO_CO2
    SO3 -->|×0.700| CaO_SO3
    Total_CaO -->|Subtract CaO_CO2 + CaO_SO3| Remaining_CaO
    Remaining_CaO -->|×0.3213| Water_equiv_CaO (Y)
    Z -->|×2.238| MgO_equiv

This concise summary and formulas help you perform lime chemical analysis per IS 6932 Part 5.

Preparation of the Sample as per IS 6932 Part 5 (1973)

• Sample Selection:
  Follow IS 712-1973 Clause 7.3 for selecting the sample for analysis.

• Sample Preparation (Clause 2.1):
  Prepare the sample as per IS 712-1973 Clause 7.2 (typically involves drying, grinding, and sieving).

• Slaking (Clause 3.1):

  • Slake the sample at 25 ± 2°C (see IS 6932 Part III).
  • Use enough water to form a stiff putty.
  • Dry the slaked sample in vacuum until constant mass is achieved.

• Chemical Analysis Procedure (Clause 3.6.2.3):

  1. Weigh 2.5 g of sample.
  2. Add 10 ml cold water, stir to break lumps.
  3. Add 20 ml dilute HCl, heat until dissolution.
  4. Filter and wash residue with hot water.
  5. Dilute filtrate to 250 ml, heat to boiling.
  6. Add 10 ml hot barium chloride dropwise with stirring.
  7. Boil 10 min, stand overnight, filter (Whatman No.42).
  8. Incinerate filter paper + precipitate, weigh BaSO4.
  9. Calculate SO3:
     [ \text{SO}_3 = \text{Mass of } \text{BaSO}_4 \times 0.343 ]

Key Formula for SO3 Content

flowchart TD
    A[Weigh 2.5 g sample]

IS 6932 Part 5: Apparatus and Equipment Key Formulas & Specifications

1. Calculations (Clause 3.6.2.5)

2. Autoclave Specifications (Clause 3.3.6)

• Pressure Gauge: Dial diameter = 114 mm, scale 0 to 40 kg/cm², divisions ≤ 0.5 kg/cm²
• Operating Pressure: 21 kg/cm² reached within 45–75 minutes
• Pressure Drop: From 21 kg/cm² to <1 kg/cm² within 12 hours after cutoff
• Safety: Automatic pressure control, safety valve, vent valve on lid

3. Furnace (Clause 3.3.5)

• Temperature controllable up to 1100°C - 1400°C
• Adjustable height using chain mechanism

Summary Diagram: Apparatus Flow

flowchart LR
    LOI[Loss on Ignition]
    CO2[CO₂ Content]
    X[Chemically Combined Water (X)]
    CaO[Calcium Oxide Total]
    SO3[SO₃ Content]
    CaO_eq[CaO Equivalents]
    Y[Water Equivalent of CaO]
    Z[Remaining Combined Water (Z)]
    MgO_eq[MgO Equivalent]

    LOI -->|Subtract CO₂| X
    CO2 -->|×1.275| CaO_eq
    SO3 -->|×0.700| CaO_eq
    CaO -->|Subtract CaO_eq| RemainingCaO
    RemainingCaO -->|×0.3213| Y
    X -->|Subtract Y| Z
    Z -->|×2.238| MgO_eq

IS 6932 Part 5: Test Procedure - Key Formulas & Specifications

Sample Preparation

• Follow Clause 2.1 referencing IS 712:1973, Section 7.2 for sample preparation.

Calculation Procedure (Clause 3.6.2.5)

Notes

• This alternative method is included because some labs may lack instruments for the earlier test.
• Ensure all chemical contents (CO₂, SO₃, CaO) are accurately determined before calculations.

flowchart TD
    A[Loss on Ignition] -->|Subtract CO₂| B[Chemically Combined Water (X)]
    B --> C[Calculate CaO Equivalents]
    C --> D[Subtract CaO Equivalents from Total CaO]
    D --> E[Calculate Water Equivalent]
    E --> F[Subtract from X to get Z]
    F --> G[Calculate MgO Equivalent]

This concise procedure ensures proper evaluation of combined water and oxide equivalents per IS 6932 Part 5.

IS 6932 Part 5 - Clause 3.6.2.5: Determination of Unhydrated Oxide

Key Calculations for Unhydrated Oxide:

1. Chemically Combined Water (X):
   [ X = \text{Loss on Ignition} - \text{CO}_2 \text{ content} ]

2. Calcium Oxide Equivalents:

   • For CO₂: Multiply by 1.275
   • For SO₃: Multiply by 0.700
     Subtract these from total estimated CaO.

3. Water Equivalent of Remaining CaO (Y):
   [ Y = \text{Remaining CaO} \times 0.3213 ]

4. Remaining Combined Water (Z):
   [ Z = X - Y ]

5. Magnesium Oxide Equivalent:
   [ \text{MgO Equivalent} = Z \times 2.238 ]

Summary Table:

This method ensures accurate quantification of unhydrated oxides in lime samples by correcting for CO₂ and SO₃ influences and converting water content to oxide equivalents.

IS 6932 Part 5 — Determination of Sulphur Trioxide (SO₃) Content

Procedure Summary (Clause 3.6.2.3)

• Weigh ~2.5 g sample.
• Add 10 ml cold water, stir to break lumps.
• Add 20 ml dilute HCl, heat until dissolved.
• Filter and wash residue.
• Dilute filtrate to ~250 ml, boil.
• Add 10 ml hot barium chloride dropwise with stirring.
• Boil 10 min, stand overnight.
• Filter on Whatman No. 42, wash with boiling water.
• Incinerate filter paper with precipitate in platinum crucible to constant mass (BaSO₄).

Calculation (Clause 3.6.2.4 & 3.6.2.5)

• SO₃ % by mass = Mass of BaSO₄ × 0.343 / Mass of sample × 100

Additional Calculations (Clause 3.6.2.5)

Key Constants

• BaSO₄ to SO₃ factor: 0.343
• CO₂ to CaO: 1.275
• SO₃ to CaO: 0.700
• CaO to water: 0.3213
• Water to MgO: 2.238

This method ensures accurate SO₃ quantification essential for quality control in cement and related materials.

IS 6932 Part 5 - Key Formulas for Calculation (Clause 3.6.2.5)

1. Calculate chemically combined water (X):
   [ X = \text{Loss on Ignition} - \text{Carbon Dioxide (CO}_2) ]

2. Calculate calcium oxide (CaO) equivalents:

   • For CO₂: multiply by 1.275
   • For Sulphur trioxide (SO₃): multiply by 0.700
     Subtract these from total CaO, then calculate water equivalent of remaining CaO:
     [ \text{Water equivalent} = \text{Remaining CaO} \times 0.3213 ]

3. Calculate remaining combined water (Z):
   [ Z = X - Y ] where ( Y ) = water equivalent of remaining CaO.

4. Calculate magnesium oxide (MgO) equivalent:
   [ \text{MgO equivalent} = Z \times 2.238 ]

Summary Table:

This method helps in the chemical analysis-based estimation of lime constituents for quality control.

IS 6932 Part 5: Reporting of Results — Key Formulas & Specifications

Clause 3.6.2.5 Calculations Summary:

Notes:

• X = chemically combined water after removing CO₂.
• Y = water equivalent of remaining CaO after removing CO₂ and SO₃ effects.
• Use distilled water as reagent per IS:1077-1960.
• Rounding off numerical values should follow the revised rules in the code.

Quick Reference Table for Equivalents:

This method helps in precise quantification of lime and combined water content in samples, crucial for quality control in building limes.

flowchart TD
    LOI[Loss on Ignition]
    CO2[CO₂ Content]
    SO3[SO₃ Content]
    CaO_Total[Total CaO Estimated]

    LOI -->|Subtract CO₂| X[Chemically Combined Water (X)]
    CO2 -->|×1.275| CaO_CO2[CaO Equivalent of CO₂]
   

IS 6932 Part 5 - Safety Precautions: Key Calculations & Specifications

From Clause 3.6.2.5 (Calculations):

1. Chemically Combined Water (X):
   [ X = \text{Loss on ignition} - \text{CO}_2 ]

2. Calcium Oxide Equivalents:

   • For (\text{CO}_2): multiply by 1.275
   • For (\text{SO}_3): multiply by 0.700

   Subtract these from total estimated (\text{CaO}).

3. Water Equivalent of Remaining (\text{CaO}) (Y):
   [ Y = \text{Remaining } \text{CaO} \times 0.3213 ]

4. Remaining Combined Water (Z):
   [ Z = X - Y ]

5. Magnesium Oxide Equivalent:
   [ \text{MgO equivalent} = Z \times 2.238 ]

Additional Specifications:

• Use distilled water as per IS: 1077-1960 for reagent purposes.
• Follow rounding rules for numerical values as revised.
• Refer to IS 6932 Part V for building lime specifications.

Summary Table:

This ensures safe handling and accurate chemical analysis in lime quality control.

IS 6932 Part 5 - References and Related Standards: Key Points

Key Calculations (Clause 3.6.2.5)

• X = Chemically combined water = Loss on ignition - CO₂ content
• Calculate CaO equivalents:
  • From CO₂: Multiply CO₂ by 1.275
  • From SO₃: Multiply SO₃ by 0.700
• Calculate water equivalent of remaining CaO: Multiply remainder CaO by 0.3213
• Remaining combined water (Z) = X - Y (water equivalent of CaO)
• MgO equivalent of Z = Z × 2.238

Related IS Standards:

• IS 1077-1960: Distilled water specification (used as reagent water)
• IS 6932 (Part V) - 1973: Method for lime testing (instrumentation note)
• Rules for rounding off numerical values (revised)
• Specification for building limes (second revision)

Summary Table of Multipliers

Contact & Offices (for reference)

• Headquarters: Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002
• Regional & Branch offices across India (Delhi, Kolkata, Chennai, Mumbai, Bangalore, etc.)

flowchart LR
    LOI(Loss on Ignition)
    CO2(Carbon Dioxide)
    SO3(Sulphur Trioxide)
    CaO(Calcium Oxide)
    X(Chemically Combined Water)
    Y(Water Equivalent of CaO)
    Z(Remaining Combined Water)
    MgO(Magnesium Oxide Equivalent)

    LOI -->|Subtract CO2| X
    CO2 -->|×1.275| CaO
    SO3 -->|