1.Pretreatment
A. The pretreatment refers to the process from oil seed with all kinds of impurities to oil extraction, it includes cleaning,shelling,cracking,conditioning,flaking and cooking.
B. the pretreatment is a very important section,it will directly affect the oil making effect.
2.Leaching
The leaching process refers to use a kind of solvent that can dissolve the oil ,through humidify the oil and molecular diffusion,then extract the oil from the castor seed flake.
3.Refining
A. the first step is degum,add the phosphoric acid to the crude oil,the weight is 1‰of the oil’s,the concentration is 85%.stir for 5 minutes then add hot water 80°C, weight is 4%of the oil.after stilling 120 minutes, let off the residue.
B. the second step is deacidify,as the castor oleic value is generally less than 6, so have to use a high concentration of lye.adding the lye into the oil(about 80°C)quickly,then stir,the still about 4 to 5 hours.at last let off the soapstock.
C. the third step is washing,heat the oil about 85°C,then add the same hot water that weigh 20% of oil ,then stir, still about 40 minutes is ok, generally washing 2 times.
D. the forth step is dry decoloring,The drying temperature keep 105–110°C, the vacuum of 0.08–0.094Mpa is a dry qualification.it have to use the dry acid clay and activated carbon, and the bleaching temperature keep about 100–110 ° C, at last filtrate after cooled to 70-80°C,then will get the refined castor oil.