Calcium hydroxide

1. Building and Building Materials
In the field of building and building materials, calcium hydroxide (also known as hydrated lime) is an indispensable basic material. Its excellent physical and chemical properties enable it to play a key role in many scenarios. Choosing high-purity calcium hydroxide and high-quality hydrated lime can significantly improve the quality and durability of building projects. Whether in traditional construction or modern infrastructure, a stable supply of calcium hydroxide and hydrated lime is an important prerequisite for ensuring construction progress.

• Mortar and Plaster Preparation: As a traditional bonding material, calcium hydroxide provides excellent plasticity and durability for mortar and plaster preparation. Hydrated lime improves the workability of mortar during mixing, reduces the risk of cracking, and is a core component for enhancing bond strength. Using standard-compliant calcium hydroxide and hydrated lime makes building structures more stable and extends their service life.

• Wall Treatment: Hydrated lime is commonly used for whitewashing and surface treatment of walls, possessing good coverage and antibacterial properties. The coating formed by calcium hydroxide effectively isolates moisture, protecting the wall substrate, while its antibacterial properties reduce mold growth. In wall treatment projects, the purity of calcium hydroxide and hydrated lime directly affects the adhesion and aesthetics of the coating.

• Soil Stabilizer: As a soil stabilizer, calcium hydroxide improves soil structure and enhances the bearing capacity of the foundation. Hydrated lime reacts with soil components to form a stable cementitious structure, strengthening the soil's compressive strength and water resistance. In infrastructure projects such as roadbeds and dams, the proper use of calcium hydroxide and hydrated lime can effectively reduce the risk of project settlement.

2. Water Treatment and Purification
The water treatment and purification industry is one of the core application areas of calcium hydroxide and hydrated lime. Their strong alkalinity and adsorption properties make them highly efficient water treatment agents. Calcium hydroxide and hydrated lime can specifically address multiple issues such as water quality adjustment, softening, and clarification, and are cost-effective and environmentally friendly, making them widely used in drinking water and industrial wastewater treatment.

• pH Adjuster: Hydrated lime effectively neutralizes acidic water, precisely adjusting the pH value of the water. Calcium hydroxide's alkalinity is mild and long-lasting, without causing drastic fluctuations in water pH, making it suitable for pH balance adjustment in drinking and industrial water. During water treatment, the dosage of calcium hydroxide and hydrated lime must be precisely controlled based on water quality testing results.

• Softening Treatment: Calcium hydroxide removes temporary hardness from water, reducing scale formation. Hydrated lime reacts with calcium and magnesium ions in water to form insoluble precipitates, thereby reducing water hardness. Using calcium hydroxide and hydrated lime for water softening effectively protects water supply pipes and water-using equipment, extending their service life.

• Flocculation and Sedimentation: Hydrated lime promotes the sedimentation of suspended solids in water, improving water clarity. Colloidal particles formed after calcium hydroxide dissolves in water adsorb impurities and suspended solids, causing them to coagulate into large particles and precipitate. In water treatment plants and wastewater treatment plants, calcium hydroxide and hydrated lime are key agents for improving water purification efficiency.

• Wastewater Treatment: Calcium hydroxide neutralizes acidic wastewater and combines with heavy metal ions to form insoluble sulfide precipitates. Hydrated lime is highly efficient and low-cost in treating acidic and heavy metal wastewater, making it a commonly used agent in industrial wastewater treatment. Using calcium hydroxide and hydrated lime to treat wastewater helps companies achieve emission standards and reduce environmental risks.

3. Environmental Protection and Pollution Control
In the field of environmental protection and pollution control, calcium hydroxide and hydrated lime, due to their strong alkalinity and chemical reactivity, have become important materials for controlling air, soil, and solid waste pollution. The environmental friendliness of calcium hydroxide and hydrated lime applications helps companies and regions achieve green development goals.

• Flue Gas Desulfurization: Hydrated lime effectively removes sulfur dioxide from industrial flue gas, reducing acid rain formation. Calcium hydroxide reacts with sulfur dioxide in flue gas to form stable calcium sulfate precipitates, achieving desulfurization. In industrial enterprises such as coal-fired power plants and steel mills, calcium hydroxide and hydrated lime are core consumables in flue gas desulfurization systems.

• Acidic Soil Improvement: Calcium hydroxide can regulate soil pH, improving the growing environment for crops. Hydrated lime neutralizes acidic substances in the soil, raising the soil pH and replenishing calcium, promoting nutrient absorption by crops. In agricultural and mining area remediation, calcium hydroxide and hydrated lime are ideal materials for improving acidic soils.

• Hazardous Waste Treatment: Hydrated lime can stabilize waste containing heavy metals, reducing its toxicity and mobility. Calcium hydroxide combines with heavy metal ions in hazardous waste to form stable compounds, reducing heavy metal pollution. In hazardous waste disposal centers, calcium hydroxide and hydrated lime are key materials for ensuring safe disposal.

• Landfills: Calcium hydroxide controls the acidity and odor of landfill leachate. Hydrated lime neutralizes acidic substances in leachate while inhibiting the volatilization of harmful gases, improving the environmental quality around the landfill. The proper use of calcium hydroxide and hydrated lime in the daily operation of landfills can effectively reduce environmental risks.

4. Food Industry Applications
In the food industry, calcium hydroxide and hydrated lime, meeting food safety standards, are widely used in traditional food processing. Their safety and functionality have been recognized by international authoritative organizations. Calcium hydroxide and hydrated lime improve food texture and enhance taste while ensuring food hygiene and safety.
Traditional Food Processing:

• Century Egg Production: Hydrated lime is a key ingredient in century egg production. It adjusts the pH value of the pickling environment, promotes gel formation, and enhances the taste and flavor of century eggs. Using food-grade calcium hydroxide and hydrated lime ensures the safety and quality stability of century eggs.

• Corn Processing (Alkaline Processing): Calcium hydroxide is used in the alkaline processing of corn to break down the fiber structure and increase starch extraction rate. The mild alkalinity of hydrated lime protects the nutrients in corn while improving the taste of processed products. Food-grade calcium hydroxide and hydrated lime are commonly used additives in the corn deep processing industry.

• Clarifying agents in sugar refining: Hydrated lime, used as a clarifying agent in sugar refining, adsorbs impurities and pigments in the sugar juice, improving the purity and color of the sugar. Calcium hydroxide neutralizes acidic substances in the sugar juice, stabilizing the pH value and laying the foundation for subsequent refining processes. The calcium hydroxide and hydrated lime used in sugar factories must meet food-grade standards.

• Safety Certification: Food-grade calcium hydroxide and hydrated lime comply with international food safety standards such as FDA and EFSA. These calcium hydroxides and hydrated limes undergo rigorous purity testing, are free of harmful impurities, and ensure the safety and compliance of food processing.

5. Chemicals and Manufacturing
In the chemical and manufacturing industry, calcium hydroxide and hydrated lime are important basic raw materials and processing aids. They are chemically reactive, inexpensive, and widely used in calcium compound production, alkali production, leather processing, and many other fields. The quality stability of calcium hydroxide and hydrated lime directly affects the yield and quality of chemical products.

• Calcium compound production: Hydrated lime is a basic raw material for manufacturing other calcium salts. Through reactions with different acids, it can produce various calcium compounds such as calcium carbonate, calcium nitrate, and calcium chloride. High purity calcium hydroxide ensures the quality of downstream calcium compound products and reduces impurity content. Chemical companies typically choose high-quality calcium hydroxide and hydrated lime as the starting point for production.

• Alkali industry: Calcium hydroxide is an important intermediate in the ammonia-soda process for producing soda ash. It reacts with ammonium chloride to produce ammonia and calcium chloride, enabling the recycling of ammonia. The reactivity of hydrated lime directly affects the yield of soda ash; high-quality calcium hydroxide and hydrated lime can improve the efficiency of the alkali production process.

• Leather processing: Hydrated lime is used in the depilatory and tanning processes of leather. It dissolves the keratin in the hair in leather, achieving gentle depilation. Calcium hydroxide adjusts the pH value of the tanning environment, enhances the binding force between the tanning agent and leather fibers, and improves the softness and toughness of the leather. Leather mills must control the impurity content of the calcium hydroxide and hydrated lime used to avoid affecting leather quality.

• Petrochemicals: Calcium hydroxide is used in the manufacture of lubricating oils and additives, neutralizing acidic impurities in lubricating oils and improving their stability and service life. Hydrated lime can also be used as an adsorbent in petrochemical production to remove harmful impurities from raw materials. The petrochemical industry has strict requirements for the purity and particle size of both calcium hydroxide and hydrated lime.

6. Other Professional Applications
In addition to the above areas, calcium hydroxide and hydrated lime play important roles in agriculture, laboratories, medicine, and many other professional fields. Their diverse functions are constantly expanding their application scope. Different professional fields have different specifications for calcium hydroxide and hydrated lime, requiring precise matching to the application scenario.

• Agriculture: Hydrated lime is used for soil disinfection and pH adjustment, killing pathogenic microorganisms in the soil and reducing crop diseases. Calcium hydroxide adjusts soil pH, improves the soil microbial environment, and enhances fertilizer utilization. Agricultural-grade calcium hydroxide and hydrated lime must meet agricultural-grade standards to ensure they are harmless to crops and the environment.

• Laboratory Use: Calcium hydroxide is used as a chemical reagent and for analytical purposes in a variety of chemical experiments and sample analyses. The hydrated lime used in laboratories is of extremely high purity with very low impurity content, ensuring the accuracy and reliability of experimental results. High-purity calcium hydroxide and hydrated lime are indispensable basic reagents in laboratories.

• Pharmaceutical Use: Hydrated lime is used in dental filling materials and disinfectants. Its antibacterial properties and biocompatibility make it widely used in oral healthcare. Dental materials made from calcium hydroxide can promote tooth tissue repair, while disinfectants can be used for oral environment disinfection. Pharmaceutical-grade calcium hydroxide and hydrated lime must meet pharmaceutical-grade standards and undergo rigorous biosafety testing.