18 
BULLETIN* 1010, U. S. DEPARTMENT OF AGRICULTURE. 
ESTIMATED TOTAL COST OF REFINING CORN OIL. 
The cost of refining vegetable oils includes such items as cost of 
chemicals, value of the oil lost in the several processes, fuel, labor, and 
overhead. In a relatively small refining operation, such as is here 
described, it is quite impossible to allocate the fuel, labor, and over- 
head expenses to the several operations. Accordingly, these items 
are charged in an estimated over-all cost of producing the finished 
edible oil. The cost of the chemicals used and the value of the oil 
lost are, however, highly specific to the several operations and can be 
charged thereto with a fair degree of accuracy. 
Table 10. — Cost of chemicals used and value of oil lost in treating 25,000 pounds of 
corn oil, containing 1.76 per cent of free fatty acids, by methods 1 and 2. 
Items of comparison. 
Method 1. Method 2. 
Weight of oil pounds. . 
Weight of free fatty acids (1.76 per cent) do. 
Sodium hydroxid necessary to neutralize the free fatty acids do. 
Total sodium hydroxid necessary do. 
Soda ash required do. 
Cost of caustic & 
Cost of soda ash c 
Value of oil lost in treatment, at 10 cents a pound: 
Method 1 (6.05 per cent) 
Method 2 (5.44 per cent) 
25,000 
440 
62.8 
a 163. 7 
25,000 
440 
62.8 
94.2 
500 
$8.19 
$4.71 
10.00 
151. 25 
136. 00 
Total cost (chemicals and value of oil lost) , 
Net cost (total cost, less the value of the soapstock, d $15.20 by method 1 and $17.32 by 
method 2) 
159.44 
144.24 
150.71 
133. 39 
Net cost of chemicals used and value of oil lost per pound of crude oil.. cent. 
Net cost of chemicals used and value of oil lost per pound of refined oil do. . 
0.577 
0.628 
0.533 
0.564 
a Method 1 requires 10 per cent of 25,000 pounds, or 2,500 pounds, of 10° Be. caustic (6.55 per cent NaOH), 
equivalent to 163.7 pounds of sodium hydroxid. 
i> Caustic soda containing 76 per cent of sodium hydroxid is quoted at $3.75 per hundredweight, which 
is equivalent to 5 cents a pound of 100 per cent sodium hydroxid, delivered. 
c Soda ash is quoted at $2 per hundredweight . 
d Soapstock is valued according to its fatty acid content. The value of soapstock for methods 1 and 2 is 
derived as follows: Weight of soapstock— (1) Caustic (sodium hydroxid solution), method 1, 2,500 pounds; 
method 2, 1,000 pounds. (2) Soda ash, method 2, 500 pounds. (3) Oil lost, method 1, 1,512.5 pounds; 
method 2, 1,360 pounds. Total, method 1, 4,012.5 pounds; method 2, 2,860 pounds. The weight of fatty 
acids in the soapstock is calculated as follows: (1) Total weight of oil lost (oil and free acid), method 1, 
1,512.5 pounds; method 2, 1,360 pounds. (2) Weight of free acids, method 1, 440 pounds; method 2, 440 
pounds. (3) Weight of oil lost, method 1, 1,072.5 pounds; method 2, 920 pounds. (4) Weight of fatty 
acids in oil lost, method 1, 986.3 pounds; method 2, 846 pounds. (5) Total weight of fatty acids, (2)+(4), 
metiiod 1, 1,426.3 pounds; method 2, 1,286 pounds. (6) Total weight of soapstock, method 1, 4,012.5 
pounds; method 2, 2,860 pounds. (7) Fatty acids in soapstock, method 1, 35.5 per cent;, method 2, 44.9 
percent.. The money value of the soapstock is calculated by the following formula: RxPXM-t-50= value 
(dollars). In this formula R is the weight of the fatty acids (in pounds), P is the percentage of fatty acids 
in the soapstock, and M is the market price per pound (in dollars). If soapstock containing 50 per cent 
of fatty acids is quoted at $0,015 per pound, the value of the soapstock, aecordingto this formula by method 1 
is 1,426.3X35.5X. 015-h50= $15.20. By method 2 the value is 1,286X44.9X. 015^50= $17.32. 
CHEMICALS AND LOSS OF OIL. 
It is evident that a very good quality of oil can be produced by 
both methods 1 and 2; hence, from this standpoint either method is 
practicable. The choice of the methods would appear, therefore, to 
depend upon which would be the more economical when such factors 
as loss of oil, cost of the chemicals used, and the time involved are 
considered. The cost of these items has been estimated on the basis 
of the results of refining the 10-pound batches for treating 25,000 
