1918.] The N.Z. Journal of Science and Technology. 
47 
The results achieved with this last furnace led me to think that experi¬ 
ments on a larger scale were justified as a preliminary to a possible com¬ 
mercial development; and at the conclusion of the small experiments I 
had command of sufficient capital for this purpose, but the possibility at 
that time of a big development of the Parapara field by a blast furnace, 
and the long period of time that I should have had to devote entirely to 
this work, deterred me from entering upon the project. 
It will be interesting now to examine the heat balance-sheet for the 
process. Assume a furnace charged with 1 lb. carbon, ] lb. Fe 3 0 4 con¬ 
taining 0-72 lb. iron and 0-28 lb. oxygen, all at 60° F., and 6 lb. air con¬ 
taining 1-38 lb. oxygen and 4-62 lb. nitrogen at 1,000° F. With perfect 
combustion of the carbon and reduction of the iron the result will be— 
0-90 lb. C0 2 containing 0*245 lb. C, 1*76 lb. CO containing 0*755 lb. C, 
0*72 lb. Fe, and 4*62 lb. N. 
The heat supplied to furnace from 0° F. will be— 
1 lb. carbon at 60° = negligible B.T.U. 
1 lb. Fe 3 0 4 at 60° = 
? ? 
61b. air at 1,000° = 
1,926 
0*245 lb. carbon to C0 2 = 
3,563 
0*755 lb. carbon to CO = 
3,360 
Total .. = 
8,849 
If the final temperature be 2,000° F., the heat leaving the furnace will 
be— 
0-90 lb. 
C0 2 at 2,000° 
= 1,213 
1-76 lb. 
. CO at 2,000° 
= 1,182 
0*72 lb. 
Fe at 2,000° 
= 163 
4*62 lb. 
N at 2,000° 
= 3,104 
Fe 3 0 4 
to Fe absorb 
.. 2,073 
7,735 
The difference, which represents the loss by radiation, is 1,114 B.T.U., which 
is equivalent to 12 J per cent, of the total heat-supply. 
Electric Melting .—On the assumption that the iron is reduced from 
2,000° to 1,000° in passing from the reducer to the melting-furnace, and 
that the product is a steel with a melting-point of 2,900°, the heat required 
to melt 1 lb. will be 0*1217 X 1900 -j- 125 = 356 B.T.U. = 0*105 kw.-hr. 
For 1 ton of 2,2401b. the energy required will be 235 kw.-hr., as compared 
with 896 kw.-hr. used in certain European experiments for the production 
of 1 ton of steel from cold scrap and pig iron. 
These figures indicate that if the chemistry of the process has been 
correctly stated it will be economically successful. Perhaps the most 
doubtful part of the process is the completeness to which reduction will 
take place in the first stage. 
Professor Waters, of the Otago School of Mines, watched a run with 
the furnace, and concluded that, bearing in mind the large consumption 
of fuel in this stage, it could be omitted entirely with advantage and the 
whole job done electrically—in fact, that the experiment proved that the 
sands could be smelted electrically. It is no doubt true that the sands 
are amenable to electric smelting, but with a great consumption of electrical 
energy. 1 lb. iron reduced from Fe 3 0 4 requires 2,880 B.T.U. for reduction 
alone; 11b. iron raised from 1,000° to melting-point requires 356 B.T.U. 
only. It is therefore very desirable that the thermal energy required for 
the reduction of the ore be supplied by coal fuel. 
