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Calcium oxide, also commonly known as quicklime, is one of the most widely used chemical compounds across various industries. From construction and metallurgy to environmental applications and chemical manufacturing, calcium oxide plays a pivotal role in day-to-day industrial operations. But what exactly is calcium oxide? How is it produced, and why is it so crucial in modern applications?
In this comprehensive guide, we’ll explore everything you need to know about calcium oxide—from its chemical properties and reactions, to its practical industrial applications, safety data, and sourcing. Whether you're a student, a researcher, or a procurement manager looking for high-purity calcium oxide, this article will help you understand the full picture.
Calcium oxide (CaO) is a white, caustic, alkaline, crystalline solid at room temperature. It is produced by the thermal decomposition of calcium carbonate (CaCO₃), typically found in limestone, in a process known as calcination.
The result? A highly reactive solid compound—quicklime—that reacts exothermically when in contact with water.
Here are some essential properties of calcium oxide:
| Property | Value/Description |
|---|---|
| Chemical Formula | CaO |
| Molar Mass of Calcium Oxide | 56.08 g/mol |
| Melting Point | 2,572°C (4,662°F) |
| Appearance | White to off-white powder or lumps |
| Solubility in Water | Reacts vigorously to form calcium hydroxide |
| Density | 3.34 g/cm³ |
| Odor | Odorless |
When heated calcium oxide is exposed to water, it undergoes a vigorous chemical reaction, releasing heat and forming calcium hydroxide (Ca(OH)₂). This is widely known as the reaction of calcium oxide with water, or slaking.
Calcium oxide is produced through a process known as calcination, which involves heating calcium carbonate (limestone) to high temperatures—typically above 900°C.
Chemical reaction:
CaCO₃ (limestone) → CaO (quicklime) + CO₂ (gas)
This reaction requires energy and is typically carried out in a rotary kiln or shaft kiln. The process of heating calcium oxide from limestone is crucial in industries like cement, steel, and glass manufacturing.
Interestingly, this process not only produces quicklime but also emits carbon dioxide, making it a topic of discussion in environmental sustainability circles and green chemistry innovations.
Yes, quicklime is essentially another name for calcium oxide. The term "quick" comes from the word "living," which is an old English term implying the compound’s reactivity—particularly its aggressive reaction with water. Therefore, quick lime calcium oxide and calcium oxide quicklime are used interchangeably.
However, the term “quicklime” is more commonly used in industrial and construction contexts, while “calcium oxide” is often used in academic and chemical documentation.
If you're wondering about the calcium oxide Lewis structure, it's pretty straightforward. Calcium (Ca) has two valence electrons, while oxygen (O) needs two electrons to complete its outer shell.
When calcium donates its two electrons to oxygen, it forms a strong ionic bond, resulting in a stable ionic compound.
Is calcium oxide ionic or covalent?
It is ionic in nature due to the electron transfer between a metal (calcium) and a non-metal (oxygen).
This ionic structure contributes to calcium oxide's high melting point, density, and chemical reactivity.
One of the most fascinating reactions of calcium oxide is its interaction with water. When you pour water on calcium oxide, it reacts vigorously and releases a significant amount of heat.
Reaction:
CaO + H₂O → Ca(OH)₂ + Heat
This exothermic reaction is used in many industrial applications, such as:
Soil stabilization
Water treatment
Flue gas desulfurization
Chemical synthesis
The resulting product, calcium hydroxide, is also known as slaked lime.
Calcium oxide’s versatility is why it’s so widely used. Let’s look at some of the top industrial applications of calcium oxide.
Used in the production of cement and mortar
Acts as a drying agent for damp soils
Enhances the durability and strength of concrete
Removes impurities in steel production
Acts as a flux in the smelting of metals
Treats acidic wastewater
Neutralizes industrial effluents
Used in flue gas desulfurization systems to reduce SO₂ emissions
Key ingredient in the production of calcium hydroxide
Used in the synthesis of various calcium salts
Acts as a pH regulator in food processing (E529)
Used in the preparation of medicines and supplements
Improves acidic soil conditions
Enhances fertilizer effectiveness
The uses for calcium oxide span across dozens of sectors. Its ability to react, purify, neutralize, and fortify makes it an irreplaceable compound in modern industry.
Given its caustic and reactive nature, understanding the calcium oxide SDS (Safety Data Sheet) is essential for anyone handling the material.
Here are key safety guidelines:
| Hazard | Description |
|---|---|
| Corrosive | Causes severe skin burns and eye damage |
| Reactivity | Reacts with water and acids |
| Inhalation Risk | Can irritate respiratory tract |
| Storage | Store in dry, well-ventilated areas |
| First Aid | Rinse immediately with plenty of water |
To understand the uniqueness of calcium oxide, let’s compare it with other common calcium compounds.
| Compound | Formula | Solubility in Water | Reactivity | Common Use |
|---|---|---|---|---|
| Calcium Oxide | CaO | Reacts violently | High | Cement, steel, desulfurization |
| Calcium Hydroxide | Ca(OH)₂ | Slightly soluble | Medium | Water treatment, pH control |
| Calcium Carbonate | CaCO₃ | Practically insoluble | Low | Chalk, antacids, fillers |
This comparison shows why calcium oxide is the preferred choice in high-temperature and high-reactivity applications.
If you're looking for industrial-grade, high-purity calcium oxide, Changshu Hongyu stands out as one of the most reliable suppliers in the global market.
Founded in 1984 with 40+ years of experience
Daily output of over 200 tons
Owns high-quality limestone mines in Hubei, China
Offers calcium oxide with high purity, low impurities, and excellent reactivity
Global supply chain with fast delivery and full certification
With the rise of green technologies and environmental engineering, calcium oxide is finding new relevance in:
Carbon capture and storage (CCS): CaO reacts with CO₂ to form CaCO₃, aiding in CO₂ sequestration.
Renewable fuel production: Used in biodiesel transesterification as a catalyst.
Hydrogen production: Plays a role in thermochemical water-splitting cycles.
These modern applications signal calcium oxide’s continued importance in a sustainability-driven world.
Q1: What is the molar mass of calcium oxide?
A1: The molar mass of calcium oxide is 56.08 g/mol. It is calculated by adding the atomic masses of calcium (40.08) and oxygen (16.00).
Q2: What happens when calcium oxide reacts with water?
A2: When calcium oxide and water reaction occurs, it forms calcium hydroxide and releases heat. This is an exothermic reaction widely used in construction and water treatment.
Q3: Is calcium oxide ionic or covalent?
A3: Calcium oxide is ionic. It forms when calcium donates two electrons to oxygen, resulting in strong electrostatic attraction between Ca²⁺ and O²⁻ ions.
Q4: What is the melting point of calcium oxide?
A4: The calcium oxide melting point is approximately 2,572°C (4,662°F), making it suitable for high-temperature industrial processes.
Q5: What is the Lewis structure of calcium oxide?
A5: In the calcium oxide Lewis structure, calcium loses two electrons (becoming Ca²⁺), and oxygen gains two electrons (becoming O²⁻), forming an ionic bond.
Q6: Is it dangerous to pour water on calcium oxide?
A6: Yes. To pour water on calcium oxide causes a highly exothermic reaction that can lead to burns or explosions if not handled properly. Always follow safety protocols.
Understanding what calcium oxide is goes beyond chemistry textbooks. It’s a foundational compound that supports construction, cleans our water, purifies our metals, and even plays a future role in carbon capture and renewable energy.
Whether you're sourcing quicklime calcium oxide for industrial use or exploring its chemical characteristics, knowing its structure, behavior, and applications is crucial.
If you're ready to explore industrial-grade calcium oxide with global delivery, technical support, and guaranteed quality, visit Changshu Hongyu for tailored solutions.Calcium oxide isn’t just a compound. It’s a cornerstone of modern industry.
