Citric acid is also known as sulphuric acid, the chemical name 2-hydroxypropane-1,2,3-tricarboxylic acid. According to its water content, it is divided into monohydrate citric acid and anhydrous citric acid. Citric acid is widely used in the food industry for more than 75% of production. It can be used as a sour agent for foods, as an antioxidant, as a pH adjuster for foods such as refreshing drinks, jams, fruits and pastries. It is used in the pharmaceutical industry for about 10%, and is mainly used as an anticoagulant, an antacid, a flavoring agent, and cosmetics. It is used in the chemical industry, etc., and is used as a buffer, a complexing agent, a metal cleaning agent, a mordant, a gelling agent, a toner, and the like. Widely in the industrial fields of electronics, textiles, petroleum, leather, construction, photography, plastics, foundry and ceramics.