What is the purpose of hydrated lime?

Lime is a common inorganic compound, usually produced by reacting quicklime with water. Hydrated lime is a fine white powder at room temperature, slightly soluble in water, and its aqueous solution is commonly known as clear lime water, which is alkaline. Due to its unique chemical and physical properties, hydrated lime has a wide and important range of applications in many fields, and has had a profound impact on human production and life.

In construction engineering, hydrated lime is a traditional masonry and plastering material. When building brick walls, lime mortar is made by mixing hydrated lime and sand in a certain proportion. This mortar has good workability and adhesion, which can tightly bond the bricks and enhance the overall integrity and stability of the wall. At the same time, lime mortar will produce a certain degree of micro expansion during the hardening process, filling the gaps between bricks and improving the sealing and waterproofing of the wall. In plastering construction, it is a plastering material mixed with gypsum, sand, etc., which can be used for leveling and decorating walls and ceilings, making the surface smooth and providing a good foundation for subsequent decoration.

Hydrated lime is also commonly used to prepare ternary soil, which is a building material made by mixing lime, clay, and sand and gravel in appropriate proportions. After compaction, the hydrated lime reacts chemically with the active silica and alumina in the clay to form a cementitious material with hydraulic properties, gradually hardening the soil and enhancing its strength and durability. Triple soil is commonly used in road base and foundation treatment projects, which can withstand certain loads, have low costs, and are easy to construct.
Using hydrated lime as the main raw material, various silicate products can be made, such as silicate bricks, silicate blocks, etc. In the production process, raw materials such as quicklime, fly ash, and sand are mixed, and appropriate amounts of water and additives are added. After forming, curing, and other processes, it undergoes hydration reaction with the active ingredients in fly ash to form a hard cement stone structure, which gives the product high strength and good durability.
This product plays an important role in wastewater treatment. It can serve as a neutralizing agent to regulate the acidity and alkalinity of wastewater. Many industrial wastewater are acidic, and direct discharge can cause serious pollution to the environment. Adding hydrated lime to acidic wastewater will cause a neutralization reaction between hydroxide ions and hydrogen ions in the wastewater, resulting in the formation of water and raising the pH value of the wastewater to meet discharge standards.

In the industrial production process, the combustion of fuels such as coal and oil produces a large amount of sulfur dioxide gas, which is one of the main pollutants in air pollution and can lead to the formation of acid rain. Lime can be used for flue gas desulfurization by spraying slurry into the flue gas. Sulfur dioxide reacts with lime to produce calcium sulfite, which is then oxidized by oxygen in the air to form gypsum.

Lime, with its diverse chemical properties and wide applicability, plays an indispensable role in many fields such as construction, environmental protection, chemical industry, agriculture, etc. It is not only an important material for building a beautiful home for humanity, but also a powerful weapon for protecting the environment, promoting industrial development, and ensuring a bountiful agricultural harvest.