RECOVERY OF POTASH IN THE BLAST-FURNACE INDUSTRY. 5 
country comes from widely scattered districts in Pennsylvania, 
New Jersey, Wyoming, Virginia, Tennessee, New Mexico, Georgia, 
and other States. 
BLAST-FURNACE FLUXES. 
Fluxing materials are used in blast furnaces to unite with the 
gangue, or impurities, of the ore and the ash of the fuel so as to render 
them fluid at furnace temperatures. It is evident, therefore, that 
the nature of the flux used is determined entirely by the character 
of the material to be fluxed. If this is acidic it requires a basic 
flux; if basic, an acid flux. In this country the gangues of iron ores 
are in practically all cases acidic in nature and consequently require 
to be combined with a base to form readily fusible compounds. In a 
few instances, such as is the case with part of the ore mined in the 
Birmingham district, the gangue itself contains such proportions of 
bases and acids as to cause it to be self-fluxing. 
The cheapest and most available basic flux is limestone. Since a 
cheap high-grade limestone can not be obtained in all localities, 
limestones containing magnesia, and even dolomites, which contain 
equal parts of lime and magnesia, are often used. 
Pennsylvania produces about one-third of the limestone used as 
pig-iron flux in this country, one-fourth comes from Michigan, and 
about one-fifth from Ohio. In Alabama dolomite is most extensively 
used for fluxing purposes in pig-iron production. 
BLAST-FURNACE FUELS. 
Coke, coal, and charcoal are the fuels used in the blast furnace. 
Of these coke holds preeminently first rank. More than 98.3 per 
cent of the pig iron produced in this country is made with the use of 
coke. Charcoal is still used in a few stacks of comparatively small 
production for the manufacture of special irons, while the use of 
anthracite coal is quite rare. Where the latter is used at all it is 
usually mixed with coke. 
Cokes are classed as beehive or by-product, dependent upon 
whether the bituminous coal is coked in beehive ovens or in by- 
product retort ovens. Beehive ovens are generally located at the 
bituminous coal mines, whereas by-product ovens are situated at 
the places of consumption. The proportion of coke produced in 
by-product coke ovens has increased from 27.5 per cent in 1913 to 
60 per cent in 1920. The division of cokes into beehive and by- 
product is based entirely on the method of manufacture and does 
not affect their use in the blast furnace. 
Pennsylvania holds first rank in the production of coke, both bee- 
hive and by-product. During the period 1913-1920 over 45.7 per 
cent of the country's total production was in this State. Alabama 
ranked second in the production of coke, with slightly over 7 per 
cent of the total, followed closely by Indiana and Ohio, with over 
6 per cent each. West Virginia and Illinois are the next largest 
producers. As previously stated by-product ovens are located at 
the place of consumption. This usually necessitates the shipment of 
the coal used in the ovens from the mines. For this reason the 
source of most of the coal used for the coke produced in Indiana, 
