Guide for the manufacture of lime in vertical mixed-feed type kiln, Part 1: From lime-stone

IS 1861 Part 1: Scope & Key Specifications

Scope (Clause 3.1):

• Applies to definitions as per IS 6508:1988 (Glossary for building lime).
• Covers specifications, testing, and quality control of lime products.

Necessary Information (Clause 2.1):

• Refer to IS 6508:1988 for terminology.
• Methods for emission measurement (IS 11255 Part 1:1985) apply for particulate matter.

Quality Control & Marking:

• Lime products must comply with BIS standards under continuous inspection and testing.
• Use of Standard Mark governed by BIS Act, 1986.

Sorting (Clause 5.9):

• Lime is cooled on floors, then hand-sorted into:
  • Well-burnt lime
  • Overburnt lime
  • Unburnt lime

Summary Table for Lime Sorting (Clause 5.9)

Additional Notes:

• Keep updated with latest amendments from BIS.
• For detailed testing and emission methods, refer to the respective IS codes.

flowchart TD
    A[Raw Lime] --> B[Cooling on Floor]
    B --> C{Sorting}
    C --> D[Well-burnt Lime]
    C --> E[Overburnt Lime]
    C --> F[Unburnt Lime]

For full details, refer to IS 1861 Part 1:1990 and related standards.

IS 1861 Part 1 - References & Key Info

• Primary Reference:

  • IS 6508:1988 — Glossary of terms relating to building lime (essential for definitions, Clause 3.1).

• Other Relevant Standards:

  • IS 11255 (Part 1):1985 — Methods for measurement of particulate emissions from stationary sources.

• Sorting Lime (Clause 5.9):

  • Lime is spread on the floor to cool, then hand-picked into:
    • Well-burnt lime
    • Overburnt lime
    • Unburnt lime

• BIS Licensing & Marking:

  • Products with the Standard Mark comply with BIS quality control and inspection.
  • License details and amendments are managed by BIS (Manak Bhavan, New Delhi).
  • Indian Standards are periodically reviewed; users should ensure they have the latest edition.

Summary Table of Key References

Contact & BIS Offices (for licensing/amendments)

• Headquarters: Manak Bhavan, New Delhi
• Regional Offices: Calcutta, Chandigarh, Madras, Bombay, etc.

This ensures proper understanding and compliance with IS 1861 Part 1 through referenced standards and BIS guidelines.

IS 1861 Part 1 (1990) - Definitions Summary

• Reference Standard for Definitions:
  Clause 3.1 states that definitions used in IS 1861 Part 1 are as per IS 6508:1988 (Glossary of terms relating to building lime).

• Key Points:

  • IS 6508:1988 provides standard terminology related to lime products such as quicklime, hydrated lime, burnt lime, overburnt lime, etc.
  • This ensures uniform understanding and application of terms in lime-related construction and testing.
  • No direct formulas or tables for definitions are provided in IS 1861 Part 1; the focus is on referencing IS 6508 for terminology.

• Additional Notes:

  • For emission measurement methods related to lime, IS 11255 (Part 1) is referenced.
  • Sorting and quality control procedures are detailed (e.g., Clause 5.9 for sorting burnt lime).

Quick Reference: Definitions Source

If you need detailed definitions or properties of lime types, refer directly to IS 6508:1988.

flowchart LR
    A[IS 1861 Part 1] --> B[Definitions]
    B --> C[Refer IS 6508:1988]
    B --> D[Emission Methods - IS 11255 Part 1]
    B --> E[Sorting & Quality - Clause 5.9]

IS 1861 Part 1 — Necessary Information Summary

Key Points from the Code:

• Clause 3.1: Definitions as per IS 6508:1988 (Glossary for building lime) apply.
• Clause 4.1: For quality lime manufacture, chemical composition of limestone and proximate analysis of fuel are essential.
• Clause 2.1: Related standards include:
  • IS 6508:1988 — Glossary of terms for lime.
  • IS 11255 (Part 1):1985 — Methods for measuring particulate emissions.
• Clause 5.9: Sorting of lime involves spreading the drawn lime for cooling and hand picking to separate:
  • Well burnt lime
  • Over burnt lime
  • Unburnt lime

Important Specifications:

Additional Notes:

• Use of the Standard Mark ensures compliance with BIS inspection and quality control.
• Periodic review and amendments are issued; always refer to the latest version.

Typical Chemical Composition Check (Example):

flowchart TD
    A[Raw Limestone] --> B[Chemical Composition Analysis]
    C[Fuel Sample] --> D[Proximate Analysis]
    B --> E[Calcination Process]
    D --> E
    E --> F[Drawn Lime]
    F --> G[Cooling & Sorting]
    G --> H{Lime Quality}
    H --> I[Well Burnt Lime]
    H --> J[Over Burnt Lime]
    H --> K[Unburnt Lime]

For detailed procedures and test methods, refer to IS 6508:1988 and IS 11255 (Part 1):1985.

IS 1861 Part 1: Manufacturing Process of Lime - Key Points

1. Chemical & Fuel Analysis (Clause 4.1)

• Essential to know:
  • Chemical composition of limestone
  • Proximate analysis of fuel
• Ensures quality lime production.

2. Sorting of Lime (Clause 5.9)

• After drawing, lime is:
  • Spread on floor for cooling
  • Hand-picked to separate:
    • Well-burnt lime
    • Overburnt lime
    • Unburnt lime

Important Notes:

• Definitions per IS 6508:1988 apply.
• Quality control and inspection are under BIS supervision.
• Use of Standard Mark signifies compliance with BIS standards.
• Regular review and amendments ensure updated practices.

Summary Table: Lime Sorting (Clause 5.9)

For detailed chemical analysis and kiln operation parameters, refer to IS 6508:1988 and kiln-specific sections of IS 1861.

flowchart TD
    A[Limestone & Fuel Analysis] --> B[Calcination in Kiln]
    B --> C[Drawn Lime]
    C --> D[Cooling & Spreading]
    D --> E{Sorting}
    E -->|Well-burnt| F[Accepted Lime]
    E -->|Overburnt| G[Reprocess/Reject]
    E -->|Unburnt| G

This process ensures production of quality lime conforming to IS standards.

Preparation of Limestone (IS 1861 Part 1)

• Limestone Size:

  • Generally 40 to 100 mm (Clause 5.1) depending on quality.

• Fuel Size:

  • Coal or coke size should be half of the limestone size range (Clause 5.2.1).
  • If limestone is 40-100 mm, coal/coke should be 20-50 mm.

• Mix Proportions for Charging (Clause 5.4.1):

  • Fuel percentage is based on heat requirements and fuel calorific value.
  • Average coal usage: 12% to 16% by mass of limestone.

Key Formula for Fuel Percentage Calculation:

[ \text{Fuel %} = \frac{\text{Heat required for calcination}}{\text{Calorific value of fuel}} \times 100 ]

flowchart LR
    A[Limestone (40-100 mm)] --> B[Mix with Fuel]
    B --> C[Fuel Size (20-50 mm)]
    B --> D[Mix Proportions]
    D --> E{Fuel Type}
    E -->|Steam Coal| F[12-16% Fuel]
    E -->|Soft Coke| G[12% Fuel]
    E -->|Firewood| H[16-20% Fuel]

Note: Chemical composition of limestone and proximate analysis of fuel (Clause 4.1) are essential for quality lime production.

IS 1861 Part 1: Preparation of Fuel for Lime Manufacture

Key Specifications (Clause 5.2 & 5.2.1)

• Fuel Size:
  • Coal/coke size should be reduced and graded.
  • Max size of coal/coke = ½ × max size of limestone.
  • Min size of coal/coke = ½ × min size of limestone.
• Moistening: Coal/coke may be moistened in hot weather before charging.

Fuel and Limestone Proportions (Clause 5.4.1, Table 1)

* Fire wood includes babul, tamarind, neem, mango, etc.

Formula for Mix Calculation:

[ \text{Mass of Fuel} = \text{Mass of Limestone} \times \text{Recommended % (by mass)} ]

Notes:

• Mix proportions depend on heat requirement and calorific value of fuel.
• Chemical composition of limestone and proximate analysis of fuel (Clause 4.1) are essential for quality lime.

flowchart LR
    A[Limestone Size] --> B[Reduce & Grade Fuel Size]
    B --> C{Fuel Size}
    C -->|Max| D[Max Coal/Coke Size = ½ Max Limestone]
    C -->|Min| E[Min Coal/Coke Size = ½ Min Limestone]
    F[Calculate Fuel Mass] --> G[Mass of Limestone × % Fuel]
    G --> H[Charge into Kiln]

This ensures efficient combustion and quality lime production.

IS 1861 Part 1 (1990) - Reserve Storage Key Points

• Clause 5.3 mandates maintaining adequate quantities of properly sized limestone and fuel in reserve at the site to ensure uninterrupted operation of lime kilns.

• While the code does not provide explicit formulas or tables for reserve storage quantities, typical engineering practice suggests:

  • Reserve Storage Volume (V) depends on:
    • Daily consumption rate of limestone and fuel (Q, in kg/day or m³/day)
    • Desired reserve duration (D, in days)

  [ V = Q \times D ]

• Sizing guidelines:

  • Limestone particle size as per IS 6508:1988 (generally 10-40 mm)
  • Fuel type and size should ensure efficient combustion; reserve fuel quantity usually covers at least 3-7 days of operation.

• Storage specifications:

  • Storage areas should be dry, well-ventilated, and protected from contamination.
  • Separate storage for limestone and fuel to prevent mixing.

Summary Table (Example)

flowchart LR
    A[Raw Material Supply] --> B[Reserve Storage]
    B --> C[Limestone Storage]
    B --> D[Fuel Storage]
    C & D --> E[Charging to Kiln]
    E --> F[Discharging of Lime]

References:

• IS 6508:1988 for limestone sizing
• Operational best practices for reserve storage sizing and handling

IS 1861 Part 1 — Charging and Discharging (Clause 5.4)

Key Specifications:

• Fuel proportion in mix: Based on heat needed for calcination & fuel calorific value.
• Average coal content: 12% to 16% by mass of limestone.

Recommended Fuel Percentages (Table 1):

Additional Notes (Clause 5.2):

• Coal/coke size must be reduced and graded before charging.
• In hot weather, moisten coal/coke to reduce dust and improve handling.

Practical Formula (Heat Balance):

[ \text{Mass of Fuel} = \frac{\text{Heat required for calcination}}{\text{Calorific value of fuel}} ]

Where:

• Heat required depends on limestone quantity and calcination energy.
• Calorific value varies by fuel type (e.g., coal ~ 3500-4500 kcal/kg).

flowchart LR
    A[Limestone + Fuel Mix] --> B[Charging into Kiln]
    B --> C[Calcination Process]
    C --> D[Discharging of Calcined Lime]

This ensures proper fuel-limestone ratio for efficient kiln operation.

IS 1861 Part 1: Temperature Control in Lime Kilns

Key Points from Clause 5.5

• Temperature Measurements at 3 points:
  • Calcination zone
  • Drawn lime
  • Exhaust gas

1. Temperature of Calcination (Clause 5.5.1)

• Measured using thermocouples through poke holes.
• Flame color indicates temperature roughly:

2. Temperature of Exhaust Gas (Clause 5.5.3)

• Should be as low as possible, preferably around 100℃ for max thermal efficiency.
• Controlled by proper pre-heating zone height.
• Gas composition for efficient combustion:
  • CO₂: 25–40%
  • CO: ≤ 0.5%
  • O₂: ≤ 3%
• About 10% excess air needed; more reduces efficiency.

Summary Diagram

graph LR
A[Calcination Zone Temp] -->|1000-1200℃ (High-calcium)| B[Flame Color]
B --> C{Flame Color}
C -->|Bright red| D[1000℃]
C -->|Bright orange| E[1200℃]
F[Exhaust Gas Temp] -->|~100℃| G[Max Thermal Efficiency]
G --> H[Gas Composition]
H --> I[CO₂ 25-40%]
H --> J[CO ≤ 0.5%]
H --> K[O₂ ≤ 3%]

Use thermocouples for accurate measurement; monitor flame color for quick checks. Maintain exhaust gas temperature and composition for efficient kiln operation.

IS 1861 Part 1: Observation of Operation of Kiln

Key Visual Observations (Clause 5.6)

• Heavy black smoke: Incomplete combustion.
• Flame at kiln top: Very wasteful condition.
• Light haze + slight smoke with reduced air: Satisfactory operation.
• Clear kiln top: Excess air supply.

Temperature Monitoring (Clause 5.5)

• Measure at 3 points:
  • Calcination zone temperature.
  • Temperature of drawn lime.
  • Exhaust gas temperature (preferably ≤ 100°C for max efficiency).

Exhaust Gas Composition & Efficiency (Clause 5.5.3)

• Exhaust gas near top poke hole analyzed per IS 11255 (Part 1):1985.
• Indicators:
  • CO ≤ 0.5% (incomplete combustion if higher).
  • CO₂ = 25–40% (higher is better for efficiency).
  • O₂ ≤ 3%.
• Maintain ~10% excess air for complete combustion; excess reduces efficiency.

Kiln Control (Clause 5.7)

• Analyze exhaust gases for CO, CO₂, O₂, and particulates.
• Adjust:
  • Air supply.
  • Limestone-fuel ratio.
  • Feed quantity.

Summary Table: Exhaust Gas Composition for Efficient Kiln Operation

flowchart LR
    A[Kiln Operation] --> B[Visual Observation]
    B -->|Black Smoke| C[Incomplete Combustion]
    B -->|Flame at top| D[Wasteful Operation]
    B -->|Light Haze| E[Satisfactory]
    B -->|Clear Top| F[Excess Air]

    A --> G[Temperature Monitoring]
    G --> H[Calcination Zone Temp]
    G --> I[Drawn Lime Temp]
    G --> J[Exhaust Gas Temp ≤ 100°C]

    A --> K[Exhaust Gas

Kiln Control Key Points (IS 1861 Part 1)

• Exhaust Gas Analysis (Clause 5.7):
  Monitor CO, CO₂, O₂, and suspended particulates to adjust:

  • Air supply
  • Limestone-fuel ratio
  • Feed quantity

• Temperature Monitoring (Clause 5.5):
  Measure temperature at:

  • Calcination zone
  • Drawn lime
  • Exhaust gas

• Exhaust Gas Temperature (Clause 5.5.3):

  • Target exhaust gas temperature ≈ 100°C for max thermal efficiency
  • Maintain proper pre-heating zone height

• Gas Composition Limits for Efficient Operation:

  Gas Component	Acceptable Range	Significance
  CO₂	25% to 40%	High CO₂ indicates good combustion
  CO	≤ 0.5%	Presence indicates incomplete combustion
  O₂	≤ 3%	Excess air should be about 10% for complete combustion

• Mass-Volume Conversion (Clause 5.4.2):
  Use mass-volume factors to estimate feed and fuel instead of weighing each time.

Summary Formula for Excess Air Calculation:

[ \text{Excess Air} = \frac{\text{Measured } O_2}{\text{Theoretical } O_2} \times 100% ]

flowchart LR
    A[Feed + Fuel] --> B[Kiln]
    B --> C[Calcination Zone Temp]
    B --> D[Drawn Lime Temp]
    B --> E[Exhaust Gas Temp & Composition]
    E --> F[Gas Analyzer (CO, CO₂, O₂)]
    F --> G[Adjust Air Supply, Fuel Ratio, Feed]

This control loop ensures efficient kiln operation by balancing combustion and thermal efficiency.

IS 1861 Part 1: Quality of Drawn Lime - Key Points

1. Chemical & Fuel Requirements (Clause 4.1)

• Chemical composition of limestone and proximate analysis of fuel are essential for quality lime manufacture.
• Proper calcination depends on raw material and fuel quality.

2. Temperature Control (Clause 5.5.2)

• Drawn lime temperature ≤ 100°C to maintain quality.
• Higher temperatures may degrade lime properties.

3. Essential Characteristics of Quality Lime (Clause 5.8)

• Proper slaking behavior.
• Good performance in mortar and concrete.
• Achieved by:
  • Correct calcination temperature.
  • Appropriate fuel type.
  • Controlled kiln operation.

Typical Chemical Composition of Good Lime

Proximate Fuel Analysis (Example)

Summary Diagram of Lime Quality Control Process

flowchart LR
    A[Limestone & Fuel Analysis] --> B[Calcination in Kiln]
    B --> C[Temperature Control (≤100°C)]
    C --> D[Drawing Lime]
    D --> E[Slaking & Testing]
    E --> F[Use in Mortar & Concrete]

In brief: Quality lime requires controlled raw materials, kiln temperature ≤100°C, and proper fuel to ensure good slaking and performance in construction.

IS 1861 Part 1 - Sorting of Lime (Clause 5.9)

• Process:
  Drawn lime is spread on the floor for cooling. It is then hand-picked to separate:

  • Well-burnt lime (desired quality)
  • Overburnt lime (excessively burnt, less reactive)
  • Unburnt lime (insufficiently burnt, ineffective)

• Purpose:
  Sorting ensures only well-burnt lime is used for construction, maintaining quality and performance.

• No explicit formulas or tables are provided in Clause 5.9 for sorting. The process is qualitative and visual.

Additional Notes (Engineering Practice)

• Sorting Criteria:

  • Well-burnt lime: White or light gray, porous, reacts well with water.
  • Overburnt lime: Dark gray or black, dense, poor reactivity.
  • Unburnt lime: Hard lumps, no reaction with water.

• Quality Control:
  Hand sorting is critical to avoid poor-quality lime affecting mortar strength.

flowchart LR
    A[Drawn Lime Spread on Floor] --> B[Cooling]
    B --> C[Hand Picking]
    C --> D[Well-Burnt Lime (Use)]
    C --> E[Overburnt Lime (Reject)]
    C --> F[Unburnt Lime (Reject)]

Summary: Sorting in IS 1861 Part 1 is a manual, visual process to ensure quality lime by separating well-burnt from defective lime before use.

IS 1861 Part 1: Recommended Fuel Proportions & Operational Guidelines

Key Specifications & Tables

1. Fuel Proportions for Charging (Clause 5.4.1)

• Fuel % by mass of limestone depends on fuel type and heat requirements.
• Typical fuel proportions (Table 1):

2. Fuel Preparation (Clause 5.2 & 5.2.1)

• Coal/coke size should be graded.
• Size limits:
  • Max coal/coke size = ½ max limestone size
  • Min coal/coke size = ½ min limestone size
• Moistening coal/coke in hot weather improves handling.

3. Chemical & Proximate Analysis (Clause 4.1)

• Essential to analyze limestone chemical composition and fuel proximate analysis for quality lime production.

Summary Formula for Fuel Mass (m_fuel):

[ m_{fuel} = \left(\frac{\text{Fuel %}}{100}\right) \times m_{limestone} ]

flowchart LR
    A[Limestone] -->|Size graded| B[Kiln Charging]
    C[Fuel (Coal/Coke/Wood)] -->|Size graded & moistened| B
    B --> D[Calcination Process]
    D --> E[Quality Lime]

Note: Adjust fuel % based on calorific value and heat requirements.