The aqueous solution of lime milk is often called lime water (lime milk or lime slurry is formed when the amount is large), and it is alkaline. It deteriorates by absorbing carbon dioxide and water in the air, and is usually said to be absorbent. It is generally used for the improvement of construction or acidic land. Lime milk is generally formed by adding water to calcium oxide, CaO + H2 2O = Ca(OH) 2 , this reaction is exothermic. Calcium oxide is dissolved in water to generate calcium hydroxide, and its solubility is not very large, so it often produces a suspension of calcium hydroxide (that is, there is still undissolved calcium hydroxide in the aqueous solution), which is lime milk. As a wide range and easy-to-prepare industrial raw materials, lime milk plays an important role in industrial production. For example, in the metallurgical industry to produce alumina, lime milk is added to the dissolution process as a dissolution additive; In the chemical industry, lime milk is not only an important raw material for the production of propylene oxide, calcium propionate and nylon, but also can be used in desulfurization systems; The sugar industry as an indispensable cheap clarifier; The building materials industry is also an indispensable raw material; In the environmental protection industry, it can also treat industrial wastewater.