12 



BULLETIN 1054, U. S. DEPARTMENT OF AGRICULTURE. 



in the soap stock and the oil, which drained into these channels upon warming,, 

 was removed from time to time until no more could be separated. 



All the oils, except F, were treated in the manner described. The 

 time required for the oils to break varied somewhat, oils D and E 

 requiring about 30 minutes to acquire a good break, and oils A, B, 

 and C slightly longer. Oil F presented some difficulty, owing to the 

 presence of mucky, solid matter, and in order to make it break within 

 a reasonable time an additional 50 per cent excess of 14° Be. sodium 

 hydroxid had to be added. Table 5 shows the refining losses result- 

 ing from this treatment. 



Table 5.- 



-Refining losses and condition of the soap stock resulting from the 

 neutralization of com oils. 





Refining loss 



(percent). 





Oils. 



After 



first 



draining. 



After 



final 



draining. 



Character of soap stock. 



Sample A, wet-process germs by ex- 

 peller. 



Sample B, wet-process germs by solvent. 



Sample C, wet-process oil cake by sol- 

 vent. 



Sample D, dry-process germs by ex- 

 peller. 



Sample E, dry-process germs by sol- 

 vent. 



Sample F, dry-process oil cake by sol- 

 vent. 



9.58 



8-27 

 14.13 



5.08 

 6.84 

 15.0 



5.65 



6.58 

 12.71 



3.69 

 6.49 

 15.0 



Sufficiently firm to permit channeling. 



Do. 



Slimy: occluded considerable oil which can 

 not be recovered to any extent by chan- 

 neling. 



Same as oil A. 



More slimy than oil D. 



Very slimy; no oil can be removed by chan- 

 neling. 



It is found that in the case of both wet-process and dry-process 

 germs the neutralization of the benzol-extracted oil results in a higher 

 refining loss than with expeller oil and that this greater loss is not 

 accounted for by any corresponding difference in the free f uttj acid 

 content. In the case of benzol-extracted oils not so much oil can be 

 recovered by channeling the soap stock as is the case with expeller 

 oils. The soap stock from the solvent oils is slimy and occludes more 

 oil than the soap stock from the expeller oils, and this oil can not 

 be recovered to any great extent. 



By reference to Table 4 it will be noted that the amount of free 

 fatty acids present will not account for the difference in the refining 

 losses obtained in the oils from wet and dry process germs. Thus 

 solvent oil B from wet-process germs with 2.15 per cent free acids 

 showed about # the same refining loss as solvent oil E from dry- 

 process germs which contained only 1.9 per cent of free acids. In 

 the case of the expeller oils from these two types of materials the free 

 fatty-acid content was about the same, yet the oil from the dry- 

 process germs showed a much smaller loss. It is probable that the 

 presence of the substances which cause the foaming of the benzol 



