THE BLAST FURNACE. 61 'i
W; PotigBerty, Superintendent of, the Pennsylvania Steel Com-, pany1, and the results are shown in'Pig.1 II-D. The curves-' express' quantitatively the relative amounts of each element or substance,: for the conditions under consideration. The height is 90 feet, -and! information is given as to the temperature to be expected at'dif-; ferent distances above the hearth. The conditions-; assumed are as i follows: :
Temperature at tuyeres, 1500° C. .''/ ,;
I Qre=60 per cent. Fe; no water., -,- . j
I ' Coke=87fcer cent.1 C ; '1888 Ibs. per ton of iron.;;: I
; Stone=10p per cent. Ca,C03; 1010 Ibs. per ton of iron. '''
\ Pig~iron=4: per cent. C; 1 per cent. Si. \ ' \
Eatio of tunnel head gas by volume, 1 C02 to iŁ CO. , |
Temperature of tunnel head gases, 260° C. ' i j ; Height of furnace, 90 feet.
jit, is assumed, upon the authority of Bell, that the carbon needed; for the ,carburization of the pig-iron is deposited in the iron oxide.; i in the tipper portion of the furnace, and that the amount so deposited is just sufficient for the work. An estimate is made of the cyanogen present. No data are given concerning silicon, sulphur j phosphorus and other elements, as their graphic representation on so small a scale would be a straight line. In the case of alumina] the amount is greater, but it has not been shown,1 as it undergoes! nt> change and affects no constituent of the charge until it reaches the zone of fusion. The isothermal lines in a blast furnace are not-horizontal, as they vary with, the irregularities in the descent of tfre'stock in different parts of the furnace, but it seemed'unnecessary to show these complicatidns.
'From this diagram we learn the following: .
; At the tunnel, head the ore (Fe203) is plunged into an atmosphere of CO=S4 per cent., C02=16 per cent., N=60 per cent., and a temperature of about 260° G. (500° P.), and there is immediately1 a reduction of part of the ore to Fe304, this action increase irig as the ore descends and reaches a higher temperature: By;the time, a idepth of 10 feet is reached, all the Fe20., has been converted into Fe3Q4 and the temperature is 450° C. (890° F.). Before this reduction is well under way, there begins the carbon deposition'by which the gases react upon the ore and deposit carbon throughout