Lime Products: The "Practical Helper" Hidden in Daily Life

When it comes to lime, many people first think of the "mortar" used in construction sites or the chemical equations in textbooks. In fact, from house renovation and soil improvement to water purification, flue gas desulfurization and industrial production, lime products have long penetrated every aspect of our lives and play a key role in many fields.

The "lime" we often refer to actually falls into two categories.

To understand lime's uses, we first need to distinguish between its "two forms" — quicklime and slaked lime, which are also the most common types of lime products in daily life.

● Quicklime

Its chemical name is calcium oxide (CaO), a white lumpy solid produced by calcining limestone (mainly composed of calcium carbonate) at high temperatures. Its most notable feature is "releasing heat when in contact with water" and quickly absorbing moisture, so it is often used as a "natural desiccant". For example, the small packet of desiccant marked "Not Edible" in the packaging of puffed foods and nuts we buy is often made of quicklime, which can effectively prevent food from getting damp and deteriorating.

● Slaked Lime

Its chemical name is calcium hydroxide (Ca(OH)₂), a product of the full reaction between quicklime and water (a process called "slaking"). It appears as a white powder, feeling delicate without obvious granularity. Its core characteristic is "weak alkalinity" — it can neutralize acidic substances without causing harm due to excessive alkalinity, which also makes it highly useful in fields such as agriculture and environmental protection.

Lime in Daily Life Scenarios

1. Construction and Renovation: Laying a Solid Foundation for Homes

Walking into a house under renovation, you will most likely see workers mixing "mortar" — and the main component of mortar is slaked lime. Mixing slaked lime with sand and cement in a proper ratio produces "cement mortar" that can firmly bond bricks and tiles, making the walls more solid and durable. The "lime milk" applied to walls (a paste made by mixing slaked lime with water) is not only low-cost and easy to construct, but also can absorb carbon dioxide in the air and gradually harden into calcium carbonate, making the walls flatter and less prone to cracking.

 2. Agricultural Production: Supplementing Nutrition for the Soil

For farmers, slaked lime is a "great helper" for soil improvement. Many farmlands gradually become acidic due to long-term use of chemical fertilizers, leading to poor crop growth and low yields. At this time, spreading an appropriate amount of slaked lime, its weak alkalinity can neutralize acidic substances in the soil, adjust the soil pH value, and restore the soil to an environment suitable for crop growth. Meanwhile, slaked lime can also increase the calcium content in the soil, helping crops such as rice and wheat enhance their resistance to diseases and pests, ensuring a more stable harvest.

In addition, in fruit tree planting, brushing "lime mortar" (made of slaked lime mixed with sulfur, etc.) on tree trunks in winter can not only kill insect eggs and bacteria on the bark to prevent pests and diseases in the coming year, but also reflect sunlight to avoid trunk cracking caused by large temperature differences between day and night in winter — it is equivalent to putting a "protective coat" on the fruit trees.

 3. Environmental Protection and Cleaning: Safeguarding a Clean and Safe Life

Calcium hydroxide is not only a "practical helper" in daily life, but also a "key treatment agent" in the field of industrial environmental protection. With the advantages of low cost and high efficiency, it plays an irreplaceable role in the treatment of wastewater, waste gas and solid waste, providing important support for the balance between industrial production and environmental protection.

 4. Industrial Production Additive

In modern industrial production, calcium hydroxide is widely used in various industries.

In papermaking production, calcium hydroxide mainly plays the dual role of pH regulator and auxiliary bleaching agent.

In rubber manufacturing, calcium hydroxide serves as a key vulcanization activator and acid neutralizer.

In the chemical industry, calcium hydroxide is a core raw material for producing calcium-based chemicals. Through reactions with different substances, it can be used to prepare various products such as calcium stearate (plastic lubricant), calcium carbonate (filler), and calcium hypochlorite (disinfectant) — these products are widely applied in downstream industries including daily chemicals, building materials, and pharmaceuticals.

In the metallurgical industry, calcium hydroxide is mainly used for acidic wastewater treatment and flue gas desulfurization.