What is calcium hydroxide?

氢氧化钙是一种白色粉末状固体。化学式Ca(OH)2，俗称熟石灰、消石灰，加入水后，呈上下两层，上层水溶液称作澄清石灰水，下层悬浊液称作石灰乳或石灰浆。上层清液澄清石灰水可以检验二氧化碳，下层浑浊液体石灰乳是一种建筑材料。氢氧化钙是一种二元中强碱(氢氧化钙在中学阶段被认为是强碱，而实际上其在水中不能完全电离，因此在大学教材中被认为是中强碱)，具有碱的通性，对外表，织物有腐蚀作用。

Calcium hydroxide is a white powdery solid. The chemical formula Ca (OH) 2, commonly known as hydrated lime and hydrated lime, forms two layers after adding water. The upper aqueous solution is called clarified lime water, and the lower suspension is called lime milk or lime slurry. The clear lime water in the upper layer can test carbon dioxide, and the turbid liquid lime milk in the lower layer is a kind of building material. Calcium hydroxide is a binary medium strong alkali (calcium hydroxide is considered as a strong alkali in middle school, but in fact it cannot be completely ionized in water, so it is considered as a medium strong alkali in College Textbooks). It has the universality of alkali and has a corrosive effect on the appearance and fabric.

氢氧化钙的用途有那些?氢氧化钙应用领域

What are the uses of calcium hydroxide? Application field of calcium hydroxide

氢氧化钙在工业中有广泛的应用。它是常用的建筑材料，也用作剂和化工原料等。

Calcium hydroxide is widely used in industry. It is a commonly used building material. It is also used as fungicide and chemical raw materials.

1、可作生产碳酸钙的原料。

1. It can be used as raw material for the production of calcium carbonate.

2、氢氧化钙属碱性，因而可以用于降低土壤的酸性，从而起到改良土壤结构的作用。农药中的波尔多液正是利用石灰乳(溶于水的氢氧化钙)和硫酸铜水溶液按照一定的比例配制而出的。冬天，树木过冬防虫，树木根部以上涂80公分的石灰浆。

2. Calcium hydroxide is alkaline, so it can be used to reduce the acidity of soil and improve the soil structure. Bordeaux liquid in pesticides is prepared by using lime milk (calcium hydroxide dissolved in water) and copper sulfate aqueous solution in a certain proportion. Trees with more than 80 cm of lime in winter.

3、品主要用于生产环氧氯丙烷、环氧丙烷。

3. High quality products are mainly used to produce epichlorohydrin and propylene oxide.

4、可用在橡胶、石油化工添加剂中，如石油工业加在润滑油中,可防止结焦、油泥沉积、中和防腐。

4. It can be used in rubber and petrochemical additives. For example, it can be added in lubricating oil in petroleum industry to prevent coking, sludge deposition, neutralization and corrosion prevention.

5、用于制取漂白粉、漂粉精、剂、制酸剂、收敛剂、硬水软化剂、土壤酸性防止剂、脱毛剂、缓冲剂、中和剂、固化剂等。

5. It is used to prepare bleaching powder, bleaching powder essence, disinfectant, acid making agent, astringent, hard water softener, soil acid inhibitor, depilant, buffer, neutralizer, curing agent, etc.

6、氢氧化钙和空气中二氧化碳还会发生反应从而形成难溶于水的碳酸钙。制糖工业生产中，先利用氢氧化钙中和糖浆中的酸，然后通入二氧化碳和剩余氢氧化钙反应生成沉淀物被过滤出去，以此减少糖的酸味。

6. Calcium hydroxide also reacts with carbon dioxide in the air to form calcium carbonate that is insoluble in water. In the sugar industry, calcium hydroxide is first used to neutralize the acid in the syrup, and then carbon dioxide is introduced to react with the remaining calcium hydroxide to form precipitates, which are filtered out, so as to reduce the sour taste of sugar.

氢氧化钙在各领域的用途

Application of calcium hydroxide in various fields

一、氢氧化钙污水处理方面的具体应用

1、 Specific application of calcium hydroxide in sewage treatment

1、氢氧化钙用在废水中可以中和废水中的游离酸。

1. Calcium hydroxide used in wastewater can neutralize free acid in wastewater.

2、氢氧化钙用在废水中可以中和废水中的酸性盐。

2. Calcium hydroxide used in wastewater can neutralize the acid salt in wastewater.

3、氢氧化钙用在废水中，其中氢氧化钙中的氢氧根离子可以与金属离子反应生产不溶于水的沉淀物。

3. Calcium hydroxide is used in wastewater, in which hydroxyl ions in calcium hydroxide can react with metal ions to produce water-insoluble sediments.

4、氢氧化钙用在废水中，可以调节废水的PH值碱性，这样可以更好的使金属氢氧化物沉淀。

4. When calcium hydroxide is used in wastewater, the pH value of wastewater can be adjusted to alkaline, which can better precipitate metal hydroxide.

二、氢氧化钙农业方面的具体应用

2、 Specific application of calcium hydroxide in agriculture

1、农业上用它降低土壤酸性，改良土壤结构; 2、农药波尔多液是用石灰乳和硫酸铜水溶液按一定比例配制的。这种用于果树和蔬菜的天蓝色粘稠的悬浊液农药，是通过其中的铜元素来消灭病虫害的。

1. In agriculture, it is used to reduce soil acidity and improve soil structure; 2. The pesticide Bordeaux solution is prepared with lime milk and copper sulfate aqueous solution in a certain proportion. This sky blue viscous suspension pesticide for fruit trees and vegetables is used to eliminate diseases and pests through copper.

其中不仅利用了氢氧化钙能与硫酸铜反应的性质，也利用了氢氧化钙微溶于水的特点使药液成粘稠性，有利于药液在植物枝叶上附着。另外氢氧化钙与空气中的二氧化碳反应生成微溶于水的碳酸钙，也有利于药液附着于植物表面一段时间不被雨水冲掉。 3、冬天，树木过冬防虫，树木根部以上涂80公分的石灰浆。

It not only makes use of the nature that calcium hydroxide can react with copper sulfate, but also makes use of the characteristics that calcium hydroxide is slightly soluble in water to make the drug solution viscous, which is conducive to the attachment of the drug solution to plant branches and leaves. In addition, calcium hydroxide reacts with carbon dioxide in the air to produce calcium carbonate slightly soluble in water, which is also conducive to the solution adhering to the plant surface for a period of time without being washed away by rain. 3. In winter, trees are protected against insects in winter, and 80 cm lime slurry is applied above the roots of trees.