Environmental Calcium Hydroxide

Environmental-Grade Calcium Hydroxide Introduction

Environmental-grade calcium hydroxide is high-activity calcium hydroxide powder suitable for environmental governance. On the basis of industrial-grade standards, it upgrades indicators including chemical reactivity and particle size control, fully meeting the stringent efficiency requirements of environmental protection fields such as flue gas desulfurization and wastewater treatment.

Properties of Environmental-Grade Calcium Hydroxide Powder

Chemical Properties: The content of calcium hydroxide (Ca(OH)₂) is stably maintained at 92%~95%, with specific surface area generally >2.5 m²/g. It features high activity and faster reaction rate than ordinary calcium hydroxide.

Physical Properties: Fineness is normally 200~325 mesh, with concentrated particle size distribution and few coarse particles. The powder is dry, loose and has good flowability.

Appearance & Color: Whiteness is generally ≥85, appearing as uniform white powder.

Moisture Content: Free moisture ≤1.5%. Moisture-proof packaging (such as coated woven bags) is required strictly to preserve the activity of finished calcium hydroxide powder.

Production Process of Environmental-Grade Calcium Hydroxide

Environmental-grade calcium hydroxide is mainly produced by a two-stage digestion system lime slaker (double-shaft mixer + chain stirring digester) to obtain high-activity calcium hydroxide. Quicklime raw material first undergoes preliminary slaking reaction in the double-shaft mixer under precisely controlled water-lime ratio (0.65~0.85:1) and suitable temperature. Afterwards, the chain stirring digester slowly turns and conveys the material over a long distance. With temperature kept above 90℃, the material undergoes sufficient homogenization, aging and deep digestion to form porous flocculent high-activity calcium hydroxide.

Then the digested calcium hydroxide is classified by a calcium hydroxide classifier. Under-reacted coarse powder returns to the digestion system for further slaking reaction, while fully reacted fine powder is collected as finished product. Finally, environmental-grade calcium hydroxide powder with specific surface area ≥2.5 m²/g, high activity and fast reaction rate is obtained, satisfying the requirements of power plant desulfurization, wastewater treatment and other environmental protection applications.

Application Fields of Environmental-Grade Calcium Hydroxide

Exhaust Gas Treatment: As an efficient alkaline absorbent, environmental-grade calcium hydroxide is widely used for flue gas purification in power, metallurgy, waste incineration and other industries, effectively removing acidic gases such as sulfur dioxide and hydrogen chloride.

Wastewater Treatment: It neutralizes acidic wastewater from electroplating, mining and other industries, and efficiently removes pollutants including heavy metals, fluorides and phosphates by forming hydroxide precipitates.

Soil Remediation: It repairs acidic soil and stabilizes heavy metal contaminated soil by adjusting pH value, and solidifies hazardous waste and acidic slag, greatly lowering the risk of pollutant migration into the environment.

Environmental Materials: It is a key raw material for manufacturing desulfurized gypsum and other eco-friendly building materials, realizing recycling of pollutants from treatment processes.

Technical Parameters of Environmental-Grade Calcium Hydroxide

Frequently Asked Questions of Environmental-Grade Calcium Hydroxide

How to test the reactivity of environmental-grade calcium hydroxide?

Multi-dimensional comprehensive verification can be carried out via specific surface area test, reactivity test, slurry performance test and simulated desulfurization experiment. The desulfurization efficiency or neutralization capacity under actual working conditions shall be used as the evaluation standard of reactivity.

How to store environmental-grade calcium hydroxide?

Environmental-grade calcium hydroxide must be stored in moisture-proof sealed packaging to isolate air and moisture strictly. The warehouse shall be dry and ventilated with ambient temperature controlled between 5~30℃. The recommended storage period is no more than 3 months. If used after expiry, effective calcium content and reactivity indicators need re-inspection.

What precautions should be taken when using environmental-grade calcium hydroxide?

Environmental-grade calcium hydroxide is a strongly alkaline powder. Operators shall wear protective gloves, goggles, dust respirators and protective clothing throughout operation to avoid skin contact and dust inhalation and prevent irritant burns. During storage, separate it from chemicals such as acids and keep it sealed in cool and dry places to avoid caking due to moisture and violent neutralization reaction from accidental mixing with acidic substances.