CASTOR-OIL INDUSTRY. age 
FINISHING THE OIL. 
REFINING. 
Various methods are recorded in the literature for refining castor 
oil. Among these may be mentioned acid refining by sulphuric 
acid, settling of the foots, and subsequent washing out of the acid. 
Other methods involve refining in alcoholic solution. As far as can 
‘be ascertained, these methods are not generally applied. British 
practice has long consisted in passing live steam into the oil, which 
serves to coagulate and precipitate the albuminlike constituents, 
which are filtered off. That this product is nitrogenous has been » 
demonstrated. The oils listed in Table VII were analyzed for 
nitrogen. 
Taste VII.—Analyses of castor-bean oils of diverse origin, showing nitrogen content. 
Nitrogen (N X 6.25) content 
: (per cent). 
Source. 
Raw. Treated. 
: ‘f 0.0159 0. 0163 . 
JACED CE ML OOYT See Sp a SL a ee Nee RE 4 “0169/0: 0164 { “0163}° 0163 
PAN ike ER Waka gs ee ere RC ee Re A Soe py a { ie . 0434 { seer . 0182 
ANGE i cee ee eee een a eee eal “Maaay - 0350 { “ply Olt 
Castor oil can not be freed from acid as readily as some of the other 
staple oils, such as cottonseed and peanut oils. Instead of the soaps 
breaking readily and settling out, the castor-oil soaps only partly do 
so but have a tendency also to dissolve in the oil, rendering the latter 
very viscous and thick. Consequently, the oil has to be very 
thoroughly washed to remove such. 
No. 1 castor oil is usually so low in acid that it serves all industrial 
purposes without refining. However, there are times when the oil 
may run high in acid, on account of the character of the beans 
received at a given plant, or the acidity may run up, owing to factory 
troubles. All No. 3 oil is high in acidity, with a range of possibly 5 
to 7 per cent figured as oleic acid. All such oil can be refined as 
follows: : 
The oil should first be heated to about 85° C. and treated with caustic-soda solution 
approximately 16° Baumé. With the temperature maintained at this point the oil 
and alkali are agitated gently to insure intimate contact, whereupon agitation is with- 
drawn and the aqueous soapy layer allowed to separate as much asit will. Itis then 
drawn off. The oil is then heated to around 95° C. and sprayed with successive por- 
tions of boiling-hot water (preferably brine) with thorough agitation. Agitation that 
is too violent produces a troublesome emulsion, which can only be broken with 
difficulty and by long heating or sweating out. If, however, the hot oil is given 
comparatively mild agitation over the layer of hot water which has settled to the bot- 
