Castor oil is a fatty oil extracted from the seeds of the plant Ricinus communis of the Euphorbiaceae family. It is an almost colorless or slightly yellow clear viscous liquid at room temperature, with a slight odor, a light taste and then a slightly spicy taste. It is insoluble in water, soluble in ethanol, benzene and carbon disulfide, and can be mixed with anhydrous ethanol, ether, chloroform or glacial acetic acid, but insoluble in mineral oil. The relative density is 0.956-0.969 (25°C), the refractive index is 1.478-1.480, the acid value is <=2.0, the saponification value is 176-186, and the iodine value is 82-90. Castor oil is mainly composed of ricinoleic acid (12-hydroxyoctadec-9-enoic acid) and oleic acid. The R1, R2 and R3 in the molecule can be the same or different. It contains 80% to 88% ricinoleic acid, 3% to 9% oleic acid, palmitic acid, stearic acid, linoleic acid, linolenic acid, dihydroxystearic acid, and the composition of glyceride is 68.2% triricinolein, 28.0% diricinolein, 2.9% monoricinolein and 0.9% nonricinolein. The ash contains a lot of calcium, iron, silicon, and inorganic elements such as aluminum, copper, magnesium, and a small amount of manganese, titanium, nickel, zinc, etc.