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E529 Calcium oxide appears as white cubic crystalline powder.
E529 Calcium oxide industrial products often contain magnesia, alumina and ferric oxide and other impurities so exhibit dark gray, light yellow or brown.
E529 Calcium oxide is soluble in acid.
CAS Number: 1305-78-8
Molecular Formula: CaO
Molecular Weight: 56.08
EINECS Number: 215-138-9
Synonyms: Calcia, Calxyl, gebrannter kalk, unslaked lime, calcium monoxide, airlock, CALX, calx usta, chaux vive, quick lime, rhenosorb C, rhenosorb F, calcium oxide CaO, desical P, lime burned, caloxal CPA, caloxol W3, Vesta PP, caloxol CP2, calcia CaO, wapniowy tlenek, Bell CML(E), Bell CML(P), oxyde de calcium, CML 21, CML 31, CML 35, lime USP, C7X2M0VVNH, CHEBI:31344, burned lime, pebble lime, heavy calcium oxide, BDFERM BIOSPRAY, RefChem:917885, CALOXOL W3, DTXCID101323191, EVECODE eco friendly sanitizer spray, 695-027-3, 1305-78-8, 215-138-9, calcium oxide, DTXSID5029631, E-529, INS-529, lime calcium oxide, quicklime, oxocalcium, Caswell No. 147A, Wapniowy tlenek Polish, oxyde de calcium French, CCRIS 7496, HSDB 1615, EINECS 215-138-9, UNII-C7X2M0VVNH, UN1910, EPA Pesticide Chemical Code 075604, Branntkalk, Kalziumoxid, Aetzkalk, calcium oxide CP, calcium oxide JP17, EC 215-138-9, calcium oxide reagent grade, SCHEMBL29352521, calcium oxide p.a. 95%, AKOS015903966, FC07719, lime meets USP specifications, calcium oxide nanopowder, calcium oxide SAJ first grade, D01679, Q185006, calcium oxide ReagentPlus 99.9%, calcium oxide anhydrous nanopowder, calcium oxide puriss FCC grade, FLUXING LIME;LIME, CAUSTIC;BURNT LIME;CALX;CALCIUM (II) OXIDE;CALCIUM OXIDE;airlock;caloxolcp2
E529 Calcium oxide, commonly known as quicklime or burnt lime, is a widely used chemical compound.
E529 Calcium oxide is a white, caustic, alkaline, crystalline solid at room temperature.
The broadly used term lime connotes calcium-containing inorganic compounds, in which carbonates, oxides, and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate.
E529 Calcium oxide, quicklime specifically applies to the single compound calcium oxide.
E529 Calcium oxide that survives processing without reacting in building products, such as cement, is called free lime.
E529 Calcium oxide, also known as quicklime or burnt lime (CaO), is a highly reactive, strongly alkaline inorganic compound produced by heating limestone (calcium carbonate, CaCO₃) at high temperatures in a process called calcination, which releases carbon dioxide and leaves behind a white, caustic solid that reacts vigorously with water and acids.
It is one of the most important basic industrial chemicals used worldwide.
E529 Calcium oxide improves industrial alkalinity control and material processing efficiency.
E529 Calcium oxide consists of calcium ions (Ca²⁺) and oxide ions (O²⁻), and when it comes into contact with water it reacts strongly and exothermically to form calcium hydroxide (E526), releasing a large amount of heat and producing a highly alkaline solution.
This reaction is so strong that it can cause boiling or splashing if not controlled properly.
E529 Calcium oxide improves its usefulness in chemical transformation and pH control systems.
Physically, E529 Calcium oxide appears as a white or grayish-white solid (lumps or powder), and it is highly caustic and hygroscopic, meaning it readily absorbs moisture and carbon dioxide from the air, gradually converting into calcium hydroxide and then calcium carbonate if exposed for long periods.
This makes proper storage in dry conditions essential.
E529 Calcium oxide improves handling awareness and storage stability requirements.
E529 Calcium oxide functions primarily as a powerful alkaline agent and industrial neutralizer, where it is used to raise pH, neutralize acids, and participate in high-temperature industrial processes such as metallurgy, construction material production, and chemical manufacturing.
Its high reactivity makes it especially valuable in large-scale industrial systems.
E529 Calcium oxide improves process efficiency in heavy industry applications.
E529 Calcium oxide is widely used as a precursor to calcium hydroxide (E526), meaning it is often intentionally converted into slaked lime before use in applications that require a milder and more controllable alkaline substance.
This two-step system (CaO → Ca(OH)₂) is fundamental in lime chemistry.
E529 Calcium oxide improves chemical processing flexibility and control.
E529 Calcium oxide is best described as a highly reactive, strongly alkaline industrial compound used for pH control, chemical processing, construction, metallurgy, and environmental treatment because of its ability to rapidly react with water, acids, and carbon dioxide, forming other important calcium-based materials in controlled industrial systems.
E529 Calcium oxide is a white caustic crystalline alkali substance that goes by the common name lime.
The term lime is used both generically for several calcium compounds and with adjectives to qualify different forms of lime.
E529 Calcium oxide entry equates lime, also called quicklime or burnt lime, with the compound calcium oxide.
E529 Calcium oxide, made by combining lime with water, is calcium hydroxide and is often referred to as slaked lime (Ca(OH)2).
E529 Calcium oxide limes contain magnesium as well as calcium.
E529 Calcium oxide is the compound calcium carbonate.
The term lime comes from the Old English word lm for a sticky substance and denotes lime’s traditional use to produce mortar.
Calx was the Latin word for lime and was used to name the element calcium.
E529 Calcium oxide is a white, odorless, and highly alkaline chemical compound.
In the food industry, it serves as an acidity regulator, firming agent, and flour treatment agent.
E529 Calcium oxide is also widely used in industrial desiccation (drying) systems, where its strong affinity for water allows it to absorb moisture very effectively, making it useful for drying gases, solvents, and certain industrial mixtures where very low humidity is required, although it must be carefully controlled because the reaction with water is strongly exothermic and can generate significant heat.
E529 Calcium oxide property makes it one of the most powerful inorganic drying agents in large-scale industry.
This improves moisture control and industrial drying efficiency.
In lime slurry production systems, E529 Calcium oxide is deliberately converted into calcium hydroxide (slaking process) to create lime milk or lime slurry, which is then used in water treatment, construction, and chemical neutralization applications where a more controllable alkaline medium is needed instead of the highly reactive dry form.
This controlled conversion is a key step in lime-based industrial chemistry.
E529 Calcium oxide improves process flexibility and safer chemical handling.
In pulp and paper manufacturing, E529 Calcium oxide is used in chemical recovery cycles and alkaline processing steps to help regenerate reagents and maintain pH balance during cellulose extraction and fiber treatment, contributing to efficient recycling of chemicals within large industrial paper production systems.
E529 Calcium oxide helps reduce chemical waste and improve sustainability in paper mills.
This improves resource efficiency and industrial sustainability.
In hazardous waste neutralization, quicklime is used to treat acidic industrial waste and contaminated sludge by raising pH rapidly and immobilizing certain heavy metals through precipitation reactions, although its use requires careful dosing because excessive alkalinity can create secondary environmental risks.
E529 Calcium oxide is commonly used in mining and chemical waste treatment plants.
E529 Calcium oxide improves toxic waste stabilization and environmental safety.
Melting point: 2570 °C
Boiling point: 2850 °C (lit.)
Bulk density: 800–1200kg/m3
Density: 3.3 g/mL at 25 °C (lit.)
Refractive index: 1.83
Flash point: 2850°C
Storage temp.: no restrictions
Solubility: 1.65 g/L — risk of violent reaction
Form: powder
Color: white to yellow-very slightly beige
Specific Gravity: 3.3
pH: 12.6 (saturated solution in H2O, 20℃)
Odor: white or gray crystals/powder, odorless
Water Solubility: reacts
Thermal Conductivity: 0.318 W/(m·K)
Crystal Structure: cubic
Sensitive: air & moisture sensitive
Merck: 14,1686
Crystal system: cube
E529 Calcium oxide is also known as lime, quick lime, burnt lime, or calx. Lime does not occur naturally since it reacts so readily with water (to form hydrated lime) and carbon dioxide (to form limestone).
E529 Calcium oxide is produced from calcium carbonate, limestone, or oyster shells by calcination at temperatures of 1,700-2,450℃.
E529 Calcium oxide is a solid with a very high affinity for water - it will react with water in the air, or in your skin or anywhere it can and form calcium hydroxide.
E529 Calcium oxide reaction is exothermic so it releases a lot of heat while it is reacting - there fore as well as being corrosive and causing significant skin irritation, calcium oxide's reaction with water can also cause burns.
E529 Calcium oxide is basically hydrated calcium oxide.
E529 Calcium oxide is alkali so can be corrosive.
E529 Calcium oxide is not found pure in nature but rather is contained in various abundant minerals (i.e. calcite, aragonite, limestone, marble) but vary greatly in their purity (impurities usually include magnesia, iron, alumina, silica, sulfur).
Of these iron and sulfur are most troublesome (i.e. where clarity is important in glass).
Lime minerals vary in the degree of crystallization and cohesion of the crystalline mass and the homogeneity of the matrix.
E529 Calcium oxide is widely used in steel and metallurgy industries, where it plays a crucial role as a fluxing agent that helps remove impurities such as silica, phosphorus, and sulfur during metal refining by forming slag, which separates unwanted materials from molten metal and improves the purity and quality of steel production.
This makes it essential in modern metallurgical processes.
E529 Calcium oxide improves metal purification and industrial efficiency.
In construction materials production, E529 Calcium oxide is used in the manufacture of cement, mortar, and lime-based binders, where it contributes to strength development through its conversion into calcium hydroxide and subsequent carbonation reactions that harden building materials over time.
Its transformation chemistry is central to traditional and modern construction systems.
E529 Calcium oxide improves structural strength and material durability.
E529 Calcium oxide is used to soften hard water by precipitating calcium and magnesium ions as insoluble compounds, and it also helps neutralize acidic wastewater streams, making it a key chemical in large-scale municipal and industrial water purification plants.
Its strong alkalinity allows efficient pH correction.
E529 Calcium oxide improves water quality and treatment performance.
In environmental pollution control, E529 Calcium oxide is used in flue gas treatment systems to remove acidic gases such as sulfur dioxide and hydrogen chloride from industrial emissions, forming solid salts that can be captured and safely disposed of.
E529 Calcium oxide is widely used in power plants and heavy industries.
This improves air pollution reduction and emission control.
In soil stabilization and agriculture, E529 Calcium oxide is used to improve acidic soils by increasing pH and enhancing nutrient availability, while also improving soil structure for construction and farming purposes by reducing moisture sensitivity and increasing load-bearing capacity.
However, it must be carefully applied due to its strong reactivity.
E529 Calcium oxide improves soil management and land usability.
In chemical manufacturing, E529 Calcium oxide is used as a raw material for producing calcium hydroxide, calcium carbide, and other calcium-based compounds that are important in industrial chemistry, plastics, and specialty material production.
It is a key starting material in lime-based chemical chains.
E529 Calcium oxide improves industrial chemical production efficiency.
In paper and sugar industries, E529 Calcium oxide is used in purification and clarification processes where it helps remove impurities and stabilize chemical conditions during large-scale processing operations.
Its strong alkalinity supports efficient separation of unwanted substances.
E529 Calcium oxide improves product purity and refining efficiency.
In construction soil drying and stabilization, E529 Calcium oxide is mixed directly into wet or unstable soils to absorb excess moisture and improve load-bearing capacity, which is especially useful in road construction, foundations, and civil engineering projects where rapid ground improvement is required.
Its ability to remove water and strengthen soil makes it highly effective in geotechnical applications.
E529 Calcium oxide improves soil stability and construction performance.
In chemical synthesis industries, E529 Calcium oxide is used as a strong base and reagent in reactions that require high-temperature or low-moisture conditions, including organic synthesis and inorganic compound production where strong alkalinity and water removal are beneficial.
Its dual role as both base and desiccant makes it industrially valuable.
E529 Calcium oxide improves reaction control and chemical production efficiency.
In glass and ceramics manufacturing, E529 Calcium oxide is used as a fluxing and stabilizing agent that helps modify melting behavior of silica-based materials, improving durability, chemical resistance, and structural integrity of final glass and ceramic products.
This contributes to the production of high-quality industrial glass and ceramic materials.
E529 Calcium oxide improves material strength and thermal stability.
In environmental odor and waste control systems, E529 Calcium oxide is used to reduce odors in sewage sludge and organic waste by raising pH and inhibiting microbial decomposition processes that produce foul-smelling gases, making it useful in municipal waste treatment plants.
E529 Calcium oxide helps improve sanitation and odor management.
This improves environmental hygiene and waste handling conditions.
In metallurgical pre-treatment processes, quicklime is used to prepare ores and remove acidic impurities before smelting, improving efficiency in metal extraction processes by creating optimal chemical conditions for later refining stages.
This is especially important in iron and steel production chains.
E529 Calcium oxide improves ore processing efficiency and metal recovery.
In advanced environmental engineering research, E529 Calcium oxide is studied for carbon capture systems, where it reacts with carbon dioxide to form calcium carbonate in a reversible cycle, making it a candidate material for long-term CO₂ sequestration technologies under controlled industrial conditions.
E529 Calcium oxide makes it relevant in climate mitigation research and industrial decarbonization.
This improves carbon management and environmental technology development.
Uses Of E529 Calcium oxide:
E529 Calcium oxide can be used in the manufacture of calcium carbide, soda ash, bleaching powder, used as building materials, refractoriness’, desiccant and soil conditioner and calcium fertilizer
E529 Calcium oxide can be used as an analysis reagent and flux agent for manufacturing fluorescence powder.
It can be used in the manufacture of calcium carbide, soda ash, bleaching powder, also used for leather, waste water purification
E529 Calcium oxide can be used as building materials, metallurgical flux agent and the major raw materials for the manufacturing of calcium hydroxide and a variety of calcium compounds.
It is also the inexpensive alkali in the chemical industry.
It is widely used in pesticides, paper, food, petrochemical, leather, waste water purification and so on.
E529 Calcium oxide can also be used for the drying of the laboratory ammonia and alcohol dehydration.
Uses as analysis reagents; E529 Calcium oxide can be applied to steel, pesticides, pharmaceuticals, non-ferrous metals, fertilizers, leather and manufacturing of calcium hydroxide, drying of laboratory ammonia, carbon dioxide absorbent and alcohol dehydration.
E529 Calcium oxide is a general food additive consisting of white granules or powder of poor water solubility.
E529 Calcium oxide is obtained by heating limestone (calcium carbonate) in a furnace.
E529 Calcium oxide is also termed lime or quicklime.
E529 Calcium oxide is used as an anticaking agent, firming agent, and nutritive supple- ment in applications such as grain products and soft candy.
E529 Calcium oxide is mainly used as a strong alkaline industrial material, fluxing agent, and chemical precursor because it reacts rapidly with water and acids, allowing it to neutralize, purify, and transform materials in many industrial processes.
In steel and metallurgy, it is used as a flux to remove impurities during metal refining.
E529 Calcium oxide improves metal purity and production efficiency.
In construction materials, it is used in cement, mortar, and lime-based binder production.
E529 Calcium oxide improves structural strength and durability.
In water treatment, E529 Calcium oxide is used to soften hard water and neutralize acidic wastewater.
This improves water quality and treatment performance.
In flue gas treatment, it is used to remove acidic gases such as sulfur dioxide from industrial emissions.
E529 Calcium oxide improves air pollution control.
In chemical manufacturing, it is used as a raw material for producing calcium hydroxide and other calcium compounds.
E529 Calcium oxide improves industrial chemical production efficiency.
In soil treatment, it is used to reduce soil acidity and improve ground stability.
E529 Calcium oxide improves agricultural and construction land quality.
E529 Calcium oxide is mainly used as a strong alkaline industrial material, drying agent, flux, and chemical precursor because it reacts rapidly with water and acids, allowing it to neutralize, dry, and transform materials in many large-scale industrial processes.
In steel and metallurgy, it is used as a fluxing agent to remove impurities such as silica, sulfur, and phosphorus during metal refining.
E529 Calcium oxide improves metal purity and production efficiency.
In construction and building materials, it is used in cement, mortar, and lime-based binder systems after being converted into calcium hydroxide.
E529 Calcium oxide improves structural strength and durability.
In water treatment, it is used to soften hard water and neutralize acidic wastewater.
E529 Calcium oxide improves water quality and treatment performance.
In flue gas treatment, E529 Calcium oxide is used to remove acidic gases such as sulfur dioxide and hydrogen chloride from industrial emissions.
E529 Calcium oxide improves air pollution control and environmental compliance.
In soil stabilization and civil engineering, E529 Calcium oxide is used to dry and strengthen wet or unstable soils for construction projects.
E529 Calcium oxide improves ground stability and load-bearing capacity.
E529 Calcium oxide is used as a raw material to produce calcium hydroxide and other calcium compounds.
E529 Calcium oxide improves industrial chemical production efficiency.
In drying applications, it is used as a desiccant to remove moisture from gases and industrial systems.
E529 Calcium oxide improves moisture control and process reliability.
In paper and pulp industries, it is used in chemical recovery and pH control processes.
E529 Calcium oxide improves production efficiency and chemical reuse.
E529 Calcium oxide is used to neutralize acidic waste and stabilize sludge materials.
This improves environmental safety and waste management.
In glass and ceramics, it is used as a flux to improve melting behavior and material strength.
This improves product quality and durability.
E529 Calcium oxide is used across metallurgy, construction, water treatment, environmental control, soil stabilization, chemical production, drying systems, and material manufacturing, mainly because of its strong alkalinity, high reactivity, and ability to remove water, neutralize acids, and modify materials in industrial processes.
Safety Profile Of E529 Calcium oxide:
A caustic and irritating material, a common air contaminant.
E529 Calcium oxide a powerful caustic to living tissue the powdered oxide may react explosively with water.
Mixtures with ethanol may igmte if heated and thus can cause an air-vapor explosion.
Violent reaction with (I3203 + CaCl2) interhalogens (e.g., BF3, CIF3), F2, HF, P2O5 + heat, water, incandescent reaction with liquid HF.
E529 Calcium oxide is a highly hazardous and strongly caustic chemical, and it is more reactive and dangerous than calcium hydroxide because it reacts violently with water and releases significant heat, which can cause burns, splattering, and thermal injury if not handled correctly.
E529 Calcium oxide requires strict industrial safety control and protective equipment.
This makes it a high-risk industrial substance.
The most serious hazard is severe chemical burns to skin and eyes, where contact with dry powder or wet mixtures can cause deep tissue damage due to its strong alkalinity and heat release during hydration.
Eye exposure can lead to permanent damage or blindness.
This makes direct contact extremely dangerous.
Inhalation of dust can cause severe respiratory irritation, including coughing, throat burns, and breathing difficulty, especially in industrial environments where fine particles are airborne.
Prolonged exposure may worsen respiratory conditions.
E529 Calcium oxide requires respiratory protection and ventilation.
E529 Calcium oxide reacts strongly and exothermically with water, which can generate enough heat to cause boiling, splashing, and secondary burns if large amounts are mixed improperly or too quickly.
This makes improper handling particularly dangerous.
E529 Calcium oxide requires controlled mixing procedures.
Skin contact can cause drying, irritation, and chemical burns, especially with prolonged or repeated exposure, and even brief contact with moisture on the skin can initiate a corrosive reaction.
Ingestion is extremely dangerous and can cause severe burns to the mouth, throat, and digestive tract, potentially leading to internal damage and life-threatening complications.
From an environmental perspective, E529 Calcium oxide can cause strong alkalization of soil and water systems, significantly altering pH and harming aquatic organisms if released improperly without neutralization.
