54 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE. 
USE OF OIL FOR ORE FLOTATION. 
Of the many oils that have come into use for ore flotation, oil 
of eucalyptus, costing about $1.50 a gallon, is prized most highly. 
Next in the order of merit come the pine oils, selling for from 40 
to 60 cents a gallon. In the effort to discover cheaper oils, most of 
the wood creosotes, as well as many coal-tar creosotes, have been 
found to be acceptable. They range in price from 15 to 30 cents a 
gallon. Producers of petroleum have also entered the flotation field, 
though with but limited success when petroleum alone is used. 
Better results are obtained by mixing a small amount of pine or 
creosote oil with the crude petroleum. ‘“ Kerosene sludge acid” 
from California oils, obtained by treating the crude oil with sul- 
phuric acid in the refining process, is also being sold for flotation. 
The sludge acid from coal tar is said to have a flotation value as 
good as or better than that from petroleum, and even coal tar itself 
is extensively used because of its low price. 
These different products entering into ore flotation may be divided, 
in a general way, into two classes, known as “frothing agents,” 
which promote foaming, and “ eollecune agents,” the Paeenion of 
which is to coat with a film of oil the mineral particles only, so 
that, adhering to the air bubbles in the foam, they are thus sepa- 
rated from the gangue. While all oils possess both frothing and 
oiling or collecting properties in some degree, eucalyptus oil, the 
pine oils, pine-tar oils (the “light” and “heavy” oils of this pub- 
lication), and crude turpentine are primarily used as frothing agents. 
Coal tar, pine tar, together with hardwood tar, and “sludge acid ” 
are used as collecting agents. Success in ore flotation demands a 
proper adjustment of these two physical properties to the particu- 
lar requirements of the ore to be treated. While all of the products 
mentioned can be used in proper combination, with some measure of 
success, the pine oils. occupy a commanding position in the field of 
ore flotation. 
Samples of pine oil and of the crude distillates obtained in the 
retort work were submitted for flotation tests to the Bureau of 
Mines Metallurgical Experiment Station, Salt Lake City, Utah, to 
ore mills in the Coeur d’Alene district, and to the testing department 
of a large copper mining company. The results from their tests 
showed that the crude turpentine was virtually as effective a flota- | 
tion agent as the pine oil, and even the light and heavy-oils were 
applicable, though requiring. a greater proportion a ton of slime, 
especially in the case of the heavy oil. Even the acid liquor was 
found useful on certain pyrite ores. 
Where, therefore, the efforts of the producers were formerly di- 
rected Eonar fcoeane the crude distillate to recover a maximum 
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