---
title: "Manufacturing process of lime"
subject: "Civil Engineering Materials"
chapter: 4
key: "semester_3/civil_engineering_materials:manufacture-of-lime"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/manufacture-of-lime
site: BCT Engineering
---

# Manufacturing process of lime

Civil Engineering Materials · Chapter 4: Lime

- Asked in: 2079 Bhadra, 2 marks; 2074 Chaitra, 2 marks (asked 2 times)
- Video: [Manufacturing of lime - Lime - Building Materials and Construction Technology](https://www.youtube.com/watch?v=pM8dWXs9n64) — Ekeeda
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/manufacture-of-lime
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-4

## Question

Explain the manufacturing process of lime.

## Short answer

Limestone is quarried, crushed, and calcined in kilns at 900–1000 °C, producing quicklime (CaO). After cooling and sorting, it is slaked with water to obtain slaked lime.

## Answer

Lime is manufactured by burning limestone (CaCO₃) in the following steps.

1. **Quarrying and selection:** pure limestone is quarried and broken into pieces of 50 to 75 mm size.
2. **Calcination:** the stone is burnt in a clamp or kiln (intermittent or continuous) at 900 to 1000 °C. The fuel is wood, coal or oil.

$$
\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2
$$

3. **Cooling and sorting:** the quicklime is drawn from the kiln, cooled, and separated from unburnt and over-burnt pieces.
4. **Slaking:** quicklime is treated with water to get slaked lime, which can be used or stored.

Continuous (vertical) kilns give a better output than clamps. Burning below the correct temperature leaves an unburnt core, and over-burning produces dead-burnt lime.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Lime is manufactured from:
   A. Clay
   B. Gypsum
   C. Sand
   D. Limestone, CaCO3
   Answer: D. Burning gives CaO. (Key point: Raw material)

2. Burning below the correct temperature leaves:
   A. Unburnt core
   B. Dead lime
   C. Ash
   D. Gypsum
   Answer: A. Over-burning makes dead lime. (Key point: Underburning)

3. After calcination the quicklime is:
   A. Dried
   B. Cooled, sorted and slaked
   C. Painted
   D. Frozen
   Answer: B. Then used or stored. (Key point: Order)

## Related in Civil Engineering Materials

- [Manufacturing process of bricks](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Amanufacturing-process-of-bricks) — Civil Engineering Materials, chapter 3, asked 4×
- [Dry process of cement manufacture](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acement-dry-process-flow-chart) — Civil Engineering Materials, chapter 5

## Related in other subjects

- [IC manufacturing, alignment and exposure](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Aphotolithography-alignment-exposure) — Embedded System, chapter 8
- [Rapid prototyping and additive manufacturing](https://www.bctengineer.com/question.md?key=semester_4%2Fcomputer_aided_design%3Arapid-prototyping-additive-manufacturing) — Computer Aided Design, chapter 6
- [Powder metallurgy process and applications](https://www.bctengineer.com/question.md?key=semester_4%2Fmanufacturing_and_production_processes%3Apowder-metallurgy-process-steps) — Manufacturing and Production Processes, chapter 4