Calcium hydroxide USP often referred to as slaked lime is a chemical compound with the chemical formula CaOH2 It is a white crystalline solid that is produced by mixing calcium oxide lime with water
Calcium Hydroxide Properties:
1. Chemical Formula: CaOH2
2. Physical State: It is commonly found in the form of a white odorless powder or colorless crystals
3. Solubility: Calcium hydroxide is sparingly soluble in water The solubility increases with temperature The resulting solution is known as lime water
4. Alkalinity: Calcium hydroxide is a strong base and when dissolved in water it produces hydroxide ions OH This property makes it useful in applications where alkalinity is required such as in water treatment processes
5. pH: Regulation Calcium hydroxide is commonly used to regulate the pH of acidic solutions or soils It reacts with acidic substances neutralizing them and raising the pH
6. Reactivity with Carbon Dioxide: Calcium hydroxide reacts with carbon dioxide in the air to form calcium carbonate 3CaCO3 a process known as carbonation This property is utilized in carbon capture technologies and is the reason why lime water turns cloudy when exposed to air
7. Health and Safety: While generally considered safe for many applications calcium hydroxide can cause irritation to the skin and eyes Dust inhalation should be avoided
8. Chemical Reactivity: Besides reacting with acids and carbon dioxide calcium hydroxide can also participate in various chemical reactions and its reactivity is exploited in different industrial processes
Applications of Calcium Hydroxide:
Soil Amendment Calcium hydroxide is used to raise the pH of acidic soils thereby improving soil structure and enhancing the availability of nutrients to plants
Liming It is employed as a liming agent to neutralize soil acidity and prevent aluminum toxicity in acidic soils
Mortar and Plaster Calcium hydroxide is a key component in the preparation of lime mortar and plaster It reacts with carbon dioxide in the air to form calcium carbonate contributing to the hardening of the material
3. Water Treatment
Softening Water Calcium hydroxide is used to soften water by precipitating calcium carbonate and magnesium hydroxide which can be removed as solid particles
pH Adjustment It is utilized in water treatment processes to raise the pH of acidic water and neutralize acidity
4. Food Industry
Pickling Calcium hydroxide is used in the pickling process to maintain the crispness of fruits and vegetables
Fortification It is used to fortify certain food products with calcium
5. Chemical Manufacturing
Chemical Reactions Calcium hydroxide participates in various chemical reactions and is used as a reactant in the synthesis of other chemicals
6. Environmental Applications
Carbon Capture Its reactivity with carbon dioxide makes calcium hydroxide useful in carbon capture technologies where it can capture and sequester CO2
7. Medical and Dental Applications
Dentistry In dental applications calcium hydroxide is used in materials for root canal treatment
Antacid It has been used as an antacid to treat digestive issues
8. Wastewater Treatment
Neutralization In wastewater treatment calcium hydroxide is used to neutralize acidic wastewater before discharge
9. Leather Industry
Liming Hides Calcium hydroxide is used in the leather industry during the liming process to remove hair and proteins from hides
10. Paints and Coatings
Hydrated Lime It is used as a filler and extender in the production of paints and coatings
Calcium Hydroxide FAQ:
Q. What is calcium hydroxide?
Ans: Calcium hydroxide often known as slaked lime is a chemical compound with the formula CaOH2 It is a white crystalline solid that is produced by reacting calcium oxide lime with water
Q. What are the common uses of calcium hydroxide?
Ans: Calcium hydroxide has various applications including soil amendment in agriculture preparation of lime mortar and plaster in construction water softening and pH adjustment in water treatment pickling in the food industry and more
Q. How does calcium hydroxide affect soil?
Ans: In agriculture calcium hydroxide is used to raise the pH of acidic soils It also improves soil structure and nutrient availability to plants
Q. Is calcium hydroxide safe for human consumption?
Ans: Calcium hydroxide is generally recognized as safe GRAS when used in food products It is used in the food industry for pickling and as a source of calcium in certain foods
Q. What is the significance of calcium hydroxide in water treatment?
Ans: Calcium hydroxide is used in water treatment to soften water by precipitating calcium carbonate and magnesium hydroxide It is also employed to raise the pH of acidic water and neutralize acidity
Q. How does calcium hydroxide react with carbon dioxide?
Ans: When exposed to carbon dioxide in the air calcium hydroxide reacts to form calcium carbonate This process known as carbonation is utilized in various applications including carbon capture technologies
Q. Can calcium hydroxide be used in construction materials?
Ans: Yes calcium hydroxide is a key component in the preparation of lime mortar and plaster in construction It reacts with carbon dioxide in the air to harden the material
Q. What precautions should be taken when handling calcium hydroxide?
Ans: While calcium hydroxide is generally safe precautions should be taken to avoid skin and eye contact Dust inhalation should also be minimized Protective gear such as gloves and goggles is recommended when handling this substance
Q. Can calcium hydroxide be used in wastewater treatment?
Ans: Yes calcium hydroxide is used in wastewater treatment to neutralize acidic wastewater before it is discharged