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Views: 0 Author: Site Editor Publish Time: 2025-05-27 Origin: Site
Calcium oxide, commonly known as quicklime, is one of the most widely used chemical compounds in industries ranging from construction to environmental protection. But what exactly happens when this highly reactive substance comes into contact with water? It's a question that sparks curiosity not only among science enthusiasts but also among professionals in sectors like chemical manufacturing, agriculture, and metallurgy.
This article explores the science behind calcium oxide's reaction with water, why it’s significant for industries, how it's managed safely, and how to choose the right type of calcium oxide product for your needs. Whether you're a student, a chemical engineer, or a procurement manager, you’ll find this guide both insightful and practical.Let’s dive deep into the world of calcium oxide and uncover what makes its reaction with water so important — and so powerful.
Calcium oxide (CaO) is a white, caustic, alkaline substance that reacts exothermically with water. This reaction is not just a simple mixing process — it involves a chemical transformation that generates significant heat and produces calcium hydroxide (Ca(OH)₂), also known as slaked lime.
CaO (Calcium oxide) + H₂O (Water) → Ca(OH)₂ (Calcium hydroxide) + Heat
This reaction is highly exothermic, meaning it releases a considerable amount of heat, which can cause the water to boil or steam instantly. That’s why to pour water on calcium oxide is not something to be taken lightly — it can be dangerous without proper safety precautions.
It’s used in industrial processes like flue gas desulfurization.
It serves as the basis for making mortar in construction.
It helps neutralize acidic soil in agriculture.
It’s used in wastewater treatment and chemical manufacturing.
Understanding this reaction is essential to safely and effectively use calcium oxide in various applications.
When you add water to calcium oxide, several things happen almost immediately:
An intense heat is released.
This can cause the water to boil or even spatter.
In industrial settings, this heat is harnessed to encourage chemical reactions.
Steam may form.
The reaction is so hot that it can produce steam even from cold water.
A white, powdery solid forms.
This is calcium hydroxide, also known as slaked lime.
Expansion occurs.
The volume of the material increases, which is important in construction use.
This reaction is widely used in applications where heat generation and basicity are beneficial. However, when not handled properly, it can result in burns, equipment damage, or safety hazards.
Calcium oxide’s reaction with water isn’t just a chemistry demonstration — it powers essential functions in many industries. Let's explore how this reaction benefits real-world applications.
In construction, calcium oxide is a key ingredient in the manufacture of mortar and cement. When mixed with water and sand or other aggregates, it forms calcium hydroxide, which sets and hardens over time by reacting with carbon dioxide in the air.
Quick setting and hardening
High bonding strength
Moisture resistance
Calcium oxide reacts with water to form slaked lime, which is used in treating acidic industrial waste and neutralizing sulfur dioxide in flue gases.
Used in flue gas desulfurization systems
Helps reduce emissions in power plants
In water treatment facilities, calcium hydroxide raises the pH of water, precipitating heavy metals and reducing pollutants.
Effective in removing phosphorus
Controls biological growth and odors
Slaked lime adjusts soil pH, improving nutrient availability and crop yields.
Neutralizes acidic soil
Improves calcium levels in soil
Calcium oxide is often used as a precursor to produce other calcium compounds.
Used in producing calcium carbide
Essential in the paper and pulp industry
| Property | Calcium Oxide (CaO) | Calcium Hydroxide (Ca(OH)₂) |
|---|---|---|
| Common Name | Quicklime | Slaked Lime |
| Appearance | White or grayish-white solid | White powder or suspension |
| Reactivity | Reacts violently with water | Stable in water |
| pH Influence | Strong base | Strong base |
| Uses | Cement, steel, water treatment | Soil amendment, water treatment, food additive |
Understanding the difference is crucial when choosing the right product for your application.
The transformation from calcium (elemental) to calcium oxide involves multiple steps:
Calcium is extracted from limestone (CaCO₃).
The limestone is heated in a kiln at high temperatures (above 900°C).
Carbon dioxide is released, leaving behind calcium oxide.
CaCO₃ → CaO + CO₂↑
This process is known as calcination.
The resulting quicklime (calcium oxide) is then stored or transported for industrial use. This entire process is energy-intensive but crucial for the global construction and chemical sectors.
At Changshu Hongyu Calcium Co., Ltd., a leading manufacturer based in China, calcium oxide products are available in various grades and purities. With over 40 years of experience and in-house mining resources, the company offers:
High Purity Quick Lime Direct from Chinese Factory
Ideal for papermaking, metallurgy, and flue gas desulfurization
Premium Quality High Whiteness Quicklime Powder
Low impurity, fast reactivity, suitable for water treatment
98% High Purity Industrial Grade Quick Lime
For use in chemical synthesis and advanced materials
These products are processed using advanced grinding and classification systems to achieve optimal reactivity and consistency.
When selecting calcium oxide for your project, consider:
Purity level
High purity ensures better performance and fewer side effects.
Particle size
Finer particles react more quickly with water.
Application needs
Construction, chemical production, water treatment — each has different requirements.
Packaging and logistics
For large-scale projects, bulk or jumbo bag options might be more economical.
Changshu Hongyu Calcium offers customizable options tailored for various industries. From 25kg bags to jumbo packaging, their products are suited for both small and large-scale operations.
Because calcium oxide reacts violently with water, safety precautions are essential:
Use protective gloves, goggles, and masks.
Ensure proper ventilation.
Store in a dry, cool place away from moisture.
In industrial settings, automated systems are often used to handle and neutralize the reaction safely.
A1: Calcium oxide is used in various industries, including construction (for mortar and cement), water treatment, environmental protection (for flue gas desulfurization), agriculture (as a soil amendment), and chemical manufacturing.
A2: Pouring water on calcium oxide causes a highly exothermic reaction, releasing heat and producing calcium hydroxide. It must be done with extreme caution, using proper protective gear and following industrial safety protocols.
A3: The molar mass of calcium oxide is approximately 56.08 g/mol, calculated from calcium (40.08 g/mol) and oxygen (16.00 g/mol).
A4: Calcium is usually extracted from limestone in the form of calcium carbonate. When calcium carbonate is heated to high temperatures (above 900°C), it undergoes calcination, releasing carbon dioxide and leaving behind calcium oxide.
A5: Quicklime is calcium oxide (CaO), while hydrated lime is calcium hydroxide (Ca(OH)₂). Quicklime reacts with water to produce hydrated lime. Quicklime is more reactive and used where high heat is beneficial, whereas hydrated lime is more stable and easier to handle.
A6: Yes, calcium oxide is widely used in water and wastewater treatment. It helps raise the pH, precipitate heavy metals, and control biological contaminants. When added to water, it forms calcium hydroxide, which performs the actual treatment.
The reaction between calcium oxide and water is more than a classroom experiment — it’s a crucial industrial process. Whether you’re looking to neutralize acidic gases, manufacture cement, treat drinking water, or improve crop yield, understanding how calcium oxide behaves in the presence of water can help you make better, safer, and more cost-effective decisions.
With the right supplier like Changshu Hongyu Calcium Co., Ltd., you can access high-purity, highly reactive calcium oxide products tailored to your specific industry needs. By leveraging this powerful chemical reaction, industries around the world are building infrastructure, protecting the environment, and improving lives — one batch of lime at a time.
