When it comes to calcium hydroxide, many people may not know what it is. It should be more familiar with slaked lime and slaked lime, especially in chemical experiments and physical experiments. So, in addition to being able to do experiments, do you know any other uses for this calcium hydroxide?
What is calcium hydroxide
Calcium hydroxide is a fine white powder produced by a professional calcium hydroxide production line, which is odorless and slightly bitter in taste. It is easy to absorb carbon dioxide and become calcium carbonate when placed in the air. It is made of calcium oxide, that is, quicklime, digested with water, dried, sieved, and air-selected (or crushed by an extension machine).
The chemical formula Ca(OH)2, commonly known as slaked lime and slaked lime, is formed into 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 supernatant clear lime water can test carbon dioxide, and the lower turbid liquid lime milk is a building material. Calcium hydroxide is a binary medium and strong base (calcium hydroxide is considered to be a strong base in the middle school stage, but in fact it cannot be completely ionized in water. It has the property of alkali and has a corrosive effect on skin and fabrics. It has a wide range of applications in industry. It is a commonly used building material, and is also used as a fungicide and chemical raw materials.
Calcium hydroxide is a strong alkaline substance with irritating and corrosive effects. Inhalation of dust is highly irritating to the respiratory tract and may also cause pneumonia. Eye contact is also strongly irritating and can cause burns.
Uses of calcium hydroxide
With the development of modern industry, lime has opened up a variety of uses in many emerging industrial sectors besides the main material of civil engineering. Such as metallurgy, glass, alkali sugar, paper, food, medicine, feed, leather, calcium carbide and organic chemicals, carbonized bricks, carbonized plates and soil improvement, water treatment, gas purification, stone cutting aids, soil stabilizers, A large amount of lime is used in concrete conditioners, chemical reagents, gypsum board caulking coagulants, building adhesive ingredients, calcium alkane sulfonates, pharmaceutical acid stoppers, astringents, hard water softeners, and plastic fibers.
1. Chemistry: Calcium hydroxide is mainly used for scientific research and development. Its high quality, high content and high price.
2. Medical aspects: Calcium hydroxide is used as a root canal sealant, and it has shown good results in killing microorganisms and reducing the toxicity to root tip tissue. Calcium hydroxide has a high anti-anaerobic effect, has bactericidal effect on Actinomyces naeviteria and Actinomycetales ichthyosis, and can significantly reduce the biological activity of G-endotoxin, can inhibit root apical tissue dissolution and periapical tissue absorption, induce Repair of periapical bone defects. Use calcium hydroxide powder and propylene glycol to make a thick paste, add an appropriate amount of iodoform to increase sterilization and make cells produce oxidation, and the effect is long-lasting, non-irritating to tissue, can promote the regression of inflammation in the apical area and the repair of lesions, prevent Pus regenerates and eventually eliminates inflammation and repairs root apical tissue.
3. Food industry: due to its strong activity and loose structure, calcium hydroxide is widely used in food additives
4. Industrial aspects: Calcium hydroxide is mainly used as an environmental neutralizer, acid waste water, sewage treatment, boiler flue gas desulfurization and building construction, as well as caustic soda and bleaching powder.
5. Agricultural aspects: it is used in agriculture to reduce soil acidity and improve soil structure; pesticide Bordeaux mixture is prepared with lime milk and copper sulfate aqueous solution in a certain proportion, so that it is used in sky blue viscous suspension pesticides for fruit trees and vegetables , is to eliminate pests and diseases through the copper element in it, which not only uses the properties of calcium hydroxide to react with copper sulfate, but also uses the point where calcium hydroxide is slightly soluble in water to make the liquid viscous, which is beneficial to the medicine The liquid adheres to the branches and leaves of plants. In addition, calcium hydroxide reacts with carbon dioxide in the air to form calcium carbonate that is slightly soluble in water, which is also beneficial for the liquid to adhere to the surface of branches and leaves and not be washed away by rainwater for a period of time.
6. Application in the construction industry: laying bricks, plastering walls, making three-compound soil, etc.
7. In terms of sewage treatment: calcium hydroxide can be used in wastewater to neutralize free acids and acid salts in wastewater; hydroxide ions in calcium hydroxide can react with metal ions to produce water-insoluble precipitates; Adjust the pH value of wastewater to alkaline, which can better precipitate metal hydroxide.
8. In coatings: calcium hydroxide reacts with carbon dioxide in the air to produce calcium carbonate, which is white and hard and can help coagulation.
9. Metallurgical industry: In this industry, in order to coat the metal surface, the impurities (containing metal oxides) on the surface of the metal plate must be removed first, so dilute sulfuric acid must be used to remove them first, and the wastewater generated in the production process should be neutralized with calcium hydroxide. .
10. On refractory materials: when producing silica bricks, it can be used as an additive to enhance the strength and viscosity of bricks. Silica bricks are made from silica with a SiO4 content of not less than 96%, adding mineralizers and binders, and going through processes such as mixing, molding, drying, and firing.
11. Application of calcium hydroxide in flue gas desulfurization : It is mainly used to neutralize acid gases such as sulfur dioxide, sulfur trioxide and a small part of fluoride ion chloride ions, etc., so that the sulfur content of discharged flue gas meets environmental protection standards.
12. Application of calcium hydroxide in leather manufacturing industry: mainly used for combing process in leather manufacturing industry.
13. Learning: applied to students’ classroom experiments.
Calcium hydroxide has a wide range of uses. It is used in medicine, food, construction, etc., and even in classroom experiments in schools. It can be said that it is ubiquitous.