What Are The Common Problems with Calcium Hydroxide？

Calcium hydroxide is a versatile inorganic base, widely used in chemical industry, construction, environmental protection, agriculture and other fields.

Calcium hydroxide is slightly soluble in water. When its powder is added to water and stirred, the clear solution on the upper layer is called clear limewater, which is often used to detect carbon dioxide in chemical experiments; the undissolved suspension or paste at the lower layer is called lime milk.

What is the difference between calcium hydroxide and quicklime (calcium oxide)?

What is the role of calcium hydroxide in wastewater treatment? What precautions should be taken during use?

Calcium hydroxide serves three primary functions in wastewater treatment:

pH Adjustment: Neutralizes acidic wastewater and adjusts the water pH to the discharge standard range of 6–9.

Coagulation and Sedimentation: Reacts with phosphate and heavy metal ions in water to form precipitates, achieving pollutant removal.

Disinfection and Sterilization: Destroys bacterial cell membranes by virtue of its alkaline environment, thereby assisting in sterilization.

Precautions for use:

It is recommended to prepare calcium hydroxide into lime milk for dosing. Compared with direct powder addition, lime milk mixes more evenly with water and prevents pipeline blockage.

Wear protective gloves and masks during operation to avoid contact between the powder and skin or respiratory tract.

Do not dose calcium hydroxide simultaneously with acidic chemicals, to prevent neutralization reaction that would render the agent ineffective.

What is the principle of using calcium hydroxide for acidic soil improvement in agriculture? How to determine the dosage?

The principle lies in utilizing the weak alkalinity of calcium hydroxide to neutralize acidic substances in the soil (such as sulfuric acid and nitric acid), thereby reducing soil acidity. Meanwhile, it supplements calcium elements in the soil and promotes the development of plant root systems.

Dosage reference:Adjust the dosage according to the soil acidity level. For slightly acidic soil, apply 50–80 kg per mu; for moderately acidic soil, apply 80–150 kg per mu. It is recommended to conduct a soil pH test in advance to avoid soil alkalization caused by excessive application.

What precautions should be taken for the transportation of calcium hydroxide? Is it classified as a dangerous good?

Calcium hydroxide is not classified as a dangerous good and can be transported as ordinary cargo, but the following precautions must be observed:

Cover the transport vehicle with a tarpaulin to prevent moisture damage in rainy weather and powder scattering during transit.

Handle with care during loading and unloading to avoid package damage.

For international transportation, provide the Material Safety Data Sheet (MSDS) of the product, clearly indicating its corrosivity and irritant properties.