240 TRANSACTIONS OF THE 
COMMERCIAL REDUCTION OF COPPER FROM 
COPPER CHLORIDE FUME. 
* BY ROBERT H. BRADFORD.1 
Copper is extracted from its ores by fire methods, by 
wet methods, and by methods involving the gasification 
or volatilization of the copper compounds. 
We have been dependent mainly on the furnace 
methods or pyrometallurgy for many years. At present 
there are important reduction plants extracting copper 
by wet methods, and continued service may be confidently 
expected from such processes in the future. Up to date 
there have been no commercial installations making 
copper at a profit by the gas methods—volatilization. 
This latter statement should not carry with it the infer- 
ence that no early work was done on volatilization of 
copper, for such is not the case. 
In the sixties of the last century Henderson of Eng- 
land received letters patent for a process which aimed at 
the recovery of copper as well as other metals from ores 
by volatilizing the metals as chlorides. 
Others followed him with experimental work in the 
same line and the U. S. patent of Pohle & Croasdale, 
issued in October, 1903, describes quite fully the volatil- 
ization of copper from sulphur-bearing ores as chloride 
by heating such ores with salt or other halogen com- 
pounds. Attempts at practical reduction of the red metal 
under these patents did not meet with success. 
The metal chloride was driven from the ore and a 
tailing of satisfactory grade was obtained but economic 
means for collecting the chloride fumes were not avail- 
able. Research investigation has been prominent of late 
to adapt the Cottrell precipitator and the bag-house to the 
1Professor of Metallurgy, University of Utah. 
