Big Bag
Industrial packaging with a 1-ton capacity that provides ease of handling.
CaO — Calcium Oxide
Quicklime
High Reactivity
Quicklime (CaO) is an industrial raw material with a strongly alkaline character, obtained by passing limestone through calcination in high-temperature kilns. It offers an indispensable solution in metallurgy, sugar production, water treatment and the paper cycle.
Formula
CaO
Melting Point
2,572 °C
Purity (CaO)
≥ 90%
pH (Aqueous)
12 - 13
Definition and Production Process
What Is Quicklime (Calcium Oxide)?
Quicklime (calcium oxide, CaO) is produced by firing naturally occurring limestone (calcium carbonate, CaCO₃) at high temperatures between 900 and 1100 °C (calcination) and removing the carbon dioxide gas. The remaining calcium oxide is a highly reactive, white-grey and strongly alkaline compound.
The resulting quicklime is hygroscopic; it rapidly draws moisture and water from the environment and enters an exothermic reaction. In the slaking reaction (on contact with water) it releases a very high amount of heat. For this reason it is frequently used as a slag former in pure form in metallurgical processes, or effectively on the ground for pozzolanic reaction needs.
Its range of use is so wide that it forms the alkaline backbone of nearly every industry, from the iron-steel sector to sugar production, and from paper to treatment. Purity ratios of >90% are targeted with special kiln technologies and selective limestone.
Chemical Calcination Reaction
CaCO₃ + Heat → CaO + CO₂
Through an endothermic reaction, limestone decomposes at around 1000°C, releasing free CaO.
Technical Data
Physical and Chemical Properties
The key parameters that determine the industrial value of quicklime are defined within the framework of the TS EN 459-1 standard.
| Parameter | Value / Range | Description |
|---|---|---|
| Chemical formula | CaO | Calcium oxide |
| Molecular weight | 56.08 g/mol | — |
| Density | 3.34 g/cm³ | Solid density |
| Melting point | 2,572 °C | Resistant to high temperatures |
| Appearance | White-grey in colour | Solid powder or lump form |
| Reactivity | Strongly exothermic | Releases strong heat with water |
| pH value | 12-13 | Strongly alkaline character |
| CaO content | ≥ 90% | High-grade calcitic lime |
Packaging Types
Shipping and Delivery Options
Our products are shipped in bulk, silo tanker (granule and powder) and big bag forms.
Silo Tanker
Direct silo-to-silo pressurized transfer for granule and powder products.
Bulk
High-volume and fast bulk shipping with tipper trucks.
In-Depth Information
From Production to Shipment: The Quicklime Chain
Quicklime (calcium oxide, CaO) is obtained by calcining limestone at high temperature and is the raw material for many lime products, including hydrated lime. Because of its high reactivity, its quality depends on the burning conditions and particle size as much as on the purity of the raw material. This section summarises what to look at when choosing the product and reading the certificate.
How does the mass change in calcination?
When limestone is calcined at roughly 900–1100 °C, carbon dioxide is released and calcium oxide remains. Assuming pure substances, 100 kg of CaCO₃ gives 56.0 kg of CaO and 44.0 kg of CO₂.
| Input | Reaction | Output |
|---|---|---|
| 100 kg CaCO₃ | CaCO₃ → CaO + CO₂ | 56.0 kg CaO + 44.0 kg CO₂ |
This is our own stoichiometric calculation; the actual yield depends on the purity of the raw material and on the kiln conditions. At Vişne Madencilik's Çukurova / Gündoğan quarry, the CaCO₃ content of the limestone is above 97% according to the company's statement; a crushing and screening plant operates on the same site.
How are reactivity, particle size and purity read?
| Parameter | What it shows | Why it matters |
|---|---|---|
| Reactivity (values such as t60) | How quickly it reacts with water | Determines efficiency in metallurgy, water treatment and chemical processes |
| Particle size distribution | How the particles are distributed across sieve sizes | Affects the slaking rate and the suitability of the feeding equipment |
| CaO + MgO | Total oxide equivalent | An indicator of overall purity |
| CO₂ | Degree of underburning and carbonation | If it is high, a larger share of the product is inactive |
| Volume stability after slaking | Whether the slaked product is stable in volume | A quality criterion in construction applications |
EN 459-1 divides calcium lime into the classes CL 90, CL 80 and CL 70 and defines reactivity and particle size classes for quicklime; the test methods are given in EN 459-2. Which class and which test method are required should be clarified at the ordering stage.
Is slaking equipment needed?
Quicklime reacts violently and exothermically with water, so slaking and dosing equipment is needed where it is used. Theoretically, 1 kg of CaO combines with about 0.32 kg of water to form 1.32 kg of hydrated lime (Ca(OH)₂). For plants without a slaking unit, ready-to-use hydrated lime may be more suitable; for the decision criteria, see our comparison article.
Our plants
Vişne Madencilik's Çelemli (Yüreğir, Adana) plant was commissioned in 2010, operates 5 kilns and has a daily capacity of 1,250 tonnes. The Narlı (Pazarcık, Kahramanmaraş) plant was commissioned in 2021, operates 4 kilns and has a capacity of 1,000 tonnes per day. The company states that its combined quicklime capacity exceeds 2,250 tonnes per day and that it exports to more than 30 countries. For the plants, see our factories page.
Storage and safety
Quicklime should be stored in a dry, closed and well-ventilated area and moved without getting wet; on contact with moisture it heats up and reacts. Its dust can cause severe irritation to the skin, eyes and respiratory tract. For safety steps, rely on the product's safety data sheet (SDS).
Industrial Use
Application Areas
Calcium oxide (quicklime) is a versatile and reactive raw material used across a wide industrial spectrum.
Iron-Steel and Metallurgy
It is the essential fluxing material in steelmaking (BOF and EAF). It binds impurities such as phosphorus, sulphur, silica and alumina from the molten metal.
Slag former (flux)Water and Wastewater Treatment
It provides the high alkalinity required in softening hard water (lime softening), heavy-metal precipitation and phosphorus removal.
High AlkalinityPaper and Pulp Industry
Used in the causticizing of sodium carbonate within the Kraft pulping process, it enables the regeneration of NaOH (caustic soda).
NaOH RecoverySugar Production
Converted into milk of lime and used in the first stage of the carbonatation process, it precipitates the chemical impurities in raw juice.
CarbonatationSoil Stabilization
It dehydrates and dries moist, soft clay soils, lowers soil plasticity through pozzolanic reactions and raises the CBR value.
Dose set by lab testsApplication Guide
Points to Consider During Use
The following technical points should be observed for the effective and safe use of quicklime.
Storage and Moisture Control
Quicklime carbonates by absorbing moisture and CO₂ from the air. It must absolutely be kept in dry, enclosed and well-insulated silos away from fan or flue draughts.
Personal Protective Equipment (PPE)
It reacts within seconds with the moisture of living skin, eyes or the respiratory tract, causing a caustic burn. A P2/P3 mask, goggles and gloves are mandatory.
Exothermic Heat Risk
When it interacts directly with water, a large amount of heat is released. Safety valves must be kept active during the slaking process.
Reactivity Observation (t60)
Different sectors require varying reactivity rates (measured as the time to reach a set temperature, e.g. 60 °C — t60); periodic control according to standards (TS EN 459-2) is essential.
Circular Economy
Even used calcium-based waste sludges can sometimes be reintegrated into circular consumption stages such as construction mortars, in line with zero-waste principles.
FAQ
Frequently Asked Questions
The most frequently asked technical and practical questions about quicklime.
Let's Find the Right Solution for Your Project Together
Contact our technical team for your lime needs. We offer our quality assurance with TS EN 459-1 compliant analysis certificates.