High-Purity Solvents, Water Treatments

Calcium Hypochlorite

Calcium Hypochlorite [Ca(ClO)₂], commonly known as High-Test Hypochlorite (HTH), is a robust inorganic compound widely utilized as a potent disinfectant, sanitizer, and bleaching agent. Produced industrially through the reaction of chlorine gas with lime (calcium hydroxide), it is preferred over liquid sodium hypochlorite due to its higher concentration of “available chlorine” (typically 65% to 70%) and its superior shelf stability. It primarily exists as a white or grayish-white granular or tablet solid. As a powerful oxidizing agent, it effectively neutralizes a broad spectrum of microorganisms, including bacteria, viruses, and algae, by disrupting cellular membranes and enzymatic functions. While highly effective, calcium hypochlorite is classified as a Class 5.1 Oxidizer (UN 1748/2880), requiring meticulous storage to prevent exothermic reactions with organic materials, acids, or moisture. Its versatility makes it indispensable in public health, industrial water management, and large-scale sanitation.

Attributes

Key Features and Benefits

High Active Potency: Contains 65–70% available chlorine, offering significantly higher disinfecting power per unit weight than liquid bleach.
Enhanced Stability: As a solid, it experiences a much slower rate of degradation over time compared to aqueous hypochlorite solutions.
Logistical Efficiency: Reduced volume and weight lead to lower shipping and storage costs and simplified inventory management.
Ease of Application: Available in granular and tablet forms, allowing for precise dosing without the need for complex liquid metering systems.
Broad-Spectrum Efficacy: Rapidly eliminates waterborne pathogens, biofilms, and organic contaminants.
Cost-Effectiveness: Provides a high return on investment for large-volume water treatment and industrial bleaching.

Specifications

Technical Highlights

Molecular Data: Formula: Ca(ClO)₂; Molecular Weight: 142.98 g/mol; CAS Number: 7778-54-3.
Solubility: Approximately 21g/100mL in water at 25°C; typically leaves a small amount of insoluble lime residue.
pH Profile: A 1% aqueous solution is strongly alkaline, typically ranging from pH 10.5 to 11.5.
Thermal Stability: Undergoes exothermic decomposition if heated above 175°C (347°F), releasing oxygen and toxic chlorine gas.
Oxidizing Power: High oxidation-reduction potential (ORP), making it effective for the destruction of cyanides and organic pollutants.
Regulatory Classification: UN 1748 (Dry) / UN 2880 (Hydrated); NFPA 704 Rating: Health 3, Flammability 0, Instability 1, OX (Oxidizer).

Download Technical Data Sheet (TDS)

Practical industry uses

Applications

Municipal Water Treatment: Used for primary disinfection of potable water and the sanitization of new or repaired water mains.
Aquatics and Leisure: Serves as a standard “shock” treatment for swimming pools and spas to eradicate algae and chloramines.
Industrial Wastewater: Utilized for odor control, cyanide neutralization in mining, and treating effluent in chemical manufacturing.
Food and Beverage Industry: Sanitization of food-processing equipment and antimicrobial wash for fruits and vegetables.
Textile and Paper: Applied as a bleaching agent for cellulose fibers, cloth, and paper pulp.
Emergency Response: Critical for rapid water purification and surface decontamination in disaster relief zones.