Citric acid, an important organic acid, also known as citric acid. Colorless crystals, often with part of crystal water, odorless, has a strong acidity, soluble in water. Its calcium salt in cold water than hot water easily dissolved, the nature of the citric acid used to identify and separate. Crystallization temperature control suitable for anhydrous citric acid obtained. In industry, food industry, cosmetic industry and so have very much use, and better human health effects.