Heat Distribution - Hearth and Bosh.

B.T.U,

Latent heat of slag formation (1,18 x 10,031) 11,800
Latent heat of iron (1.18 x 13,923) 16,420
Reduction of 5% of Fe 203 (1.18 x 17,000) 20,070
Reduction of Sil, (1.18 x 9,500 ) 11,210
Cooling water, radiation & conduction 55,459
114, 737

Heat Distribution - Shaft.

B.T.U.

Heating coke to 2750°F (1504°C) 95,570
Reduction of Fe,0, = (1.18 x 313,494), 369,923
Heating slag forming maperiets to 2740 F(1,18 x 49,900) 58,900
Heating iron to 2740°F (1.18 x 48,900) 57,720
Radiation from previous figure 69,000
651,113

The figures show a deficiency of 1,743 B.t.ue in shaft heat. However,
the same amount of radiation is assumed for this study as for the last, while
the top will be considerably cooler, also the gas is assumed as escaping at
450°F, It will probably be found that the top gas will be cooler than this.

Comparison of Operating Costs between Furnaces
Using Ordinary Air and Enriched Air

In order to give an idea of the value of such a process to the in-
dustry, the following comparison of costs have been prepered; but in comparing
these costs it is well to bear in mind thet we are using the enriched blast in
a furnace designed for atmospheric air, and that to obtain the greatest bene-
fits from the application of oxygen to the process we shall probably be ob-
liged to change the furnace design.


Cu.ft. Per cent

ive) 13.20 41.07
CHy 1.94 6.04
CoH4 1.72 5.35
Ca 1.98 6.16
Hp 12.83 39.92
03 Oval 0.65
Np 0.26 0.81
Total volume 32.14

Net calorific power of gas, b.teu, 400

Total calorific power of gas per 1b. of coal

(less sensible heat) b.t.ue 129856
Steam used per 1b. of coal, 1b. 0.5168
Steam used per 1000 cu.ft. of gas, 1b. 16,078
Assuming 8 1b. of steam eqrivalmt to 1 1b.

of coal:
Coal to supply steam per 1000 cu,ft. of gas, 1b. 2.01
Coal gasified per 1000 cu.ft. of gas, 1b. 31.11
Total coal per 1000 cu.ft. gas, 1b. 33.12
Oxygen content of gas per 1000 cu.ft. lb. 24.4136
Oxygen in coal per 1000 cu.ft. of gus, 1b. 3.4221
Oxygen in steam per 1000 cu.ft. of gus 14.2912
Oxygen in blast per 1000 cu.ft. of gas, 1b. 6.7003
Cu.ft. oxygen necessury per 1000 cu.ft. of gas,

cusfts 7514

Now for comparison let us consider water-gas practice with a producer
operating on coke of 90% C end 10% ash, making gas as follows:

Waste ges for period of 2 minutes.

Per cent
C2 17.9
co 1.8
Np 78.6
03 1,7
Water gas for period of 8 mimtes.
Per cent
B. 50
ob 40
Og 5
0. 1
x 2
Volume of waste gas per cycle, cu.ft. 16,222
Carbon in waste gas, lb. 107.6466
Water gas produced, cuift. 7,027
Carbon in weter gas, lb. 106 .0023
Totel carbon gasified per cycle, 1b. 213 .6489

Carbon gasified per 1000 cu.ft. of weter gas, lb. 30.40

~35-


blast-furnace gas with oxygen will not improve this lack of illuninants, but
it will increase the speed of combustion and increese the calorific intensity
of the flume beyond that of current opemhearth practice, This is only one
of the many cheap fuels which should be tried in this respect.

On page 22 was mentioned the desirability of a more highly refractory
material for the roof and ports in order to conserve heat, end if we can ob-
tain such a material which will allow us to ettein higher temperature in the
furnace we will then be in a positicn to effect the greatest fuel eccnory
with oxygen by increasing the combustion temperature. The greater portion of
the heat absorbed by the bath in the furnace is from the flame, and is trans-
mitted by conduction, convection, and radiation. ‘the quantity of heat trans-
mitted by conduction and convection is in proportion to the difference in
temperature. Now, by Clement's figures, the calculated flame teunerature is
1800°C., and the observed. tempereture of the finished steel is 160°C, Let
us essume, for example, that the mean temperature of the charge during the
operation is 900°S., then tne average Gifference in the flame end cherge tem-
peratures is 900° . From this, each increase in flame temperature of 100° will
increase the rate of heat-transfer approximately 1/9, and decrease the necessary
time for heating the charge in like mzmer. This is not strictly correct, in
that we can not consider mean differsuce in temperature, but is sufficiently
close to form some estimate of the possibility. New, the latter maarer of
heat-transfer - that is, radiation, is proportional in rate to the difference
of the fourth powers of the absolute temperatures. Radiation contributes a
considerable share of the heat to the furnace, the exact amount not being
known, but with this portion of the heat increasing as the fourth power of the
absolute temperatures involved one can realize the tremendous effect on rate
of driving that the increase of flame tempereture will accomplish.

Consideration of Chemical Problems of the Open Hearth.

So far we have considered only the thermal side of the open hearth,
so let us laok at the possible application of oxygen ‘© the chemival side as
well, The open-hearth process is essentially one of oxidation. Pig ison and
scrap steel are charged in a furnace, melted dowm, and the impvritius are
oxidized out, leaving as @ product a meterial which has lost a eat part of
its phosphorous, sulphur, silicon, manganese, and carton, The chief oxidizing
agent being iron ore. In introducing iron ore we ere also introducicg further
impurities, mainly phosphorous and silica, which have a tendency to lower the
quality of the product. If we could accomplish our oxidation bly means of
oxygen we would eliminate thése additional impurities.

Our next consideration is the time element. To oxidize a bath to the
desired quality, using iron ore, requires from 3 to 5 hours, tut if we vould
use oxygen for this purpore it may be acco: ss then 30 minutes.
Oxidation by iron ore is an vthermic : izes the reduc
tion to iron of the ore charged, and therefore absorbs heat ju the furnece.
Oxidation by oxygen is highly exethermic and will eda greatly to the evailable
heat in the bath, another factor which will tend to shorten the process.

Now as. to cost, we pay from $4 to $6 per ton of iron ore for this
purpose. This ore contains about 90% Fe30g or 27% available oxygen. We are
of course utilizing the iron content of the ore as well, tut thet is incidental
to the fact thet the ore is used for its oxidizing power; 98% oxygen for this

-31-


E

SE PRACTIC.

SSENT FERRCUANGAN.

PRE:

| sen

go aumtoa ¢

F009 |
qe seg “FFD

“a 7b “@ ‘ayeus
oy veer T2305 |

159, 832 BTU,

“ML a ¥Feug 0F
GyH Wolsy FLoy

171,062 171,062

“Mad wots
-snquiov fo yvay

"| erarers
S) sep doy uy yeoq

Bo0kg | rte we eceee
42 “QT tad
sep Ut “NL

-eeswonee,

“at ‘ayeus .
UT PSsvelTsy
“sq
ysog yo dol ay a >
lewd ene inl Day

442, 332

hae as ta
sey Aq uotqoeS o 4 a

PH Wory pata oo. CS
~1Co 7287]. Teqoy, ~ wo

“MLA FXT
qe “GT aod yeoq

ig ‘Fa
qe eammyesaduaey,

ysog @ 4UyTeaH -
oF yeeH Teor] A

661,902 B.7.U,

m

“qy aed uoty
-snquioo JO yeeH

Hearth and Bosh

“AL g souerjug
ye “qt tad yeoy

Ysog @ UArecH
ut “aq

91.0
95
2,2

2
C- for reduc-
tion of SiO.

C- totel
charged

Iten

Op

2
#20

from H20
from Fe203
from CO + 02
o~ from Lime ston

-remaining

Con=
is}
Q5- total

lo- from

un Ore

2 from Blast 71,2

(Dry)

Q5 total from
Blast (Moist)
C- in Metal

e

iB Blast

O2 from
CO- oxydized by

C- burned by
0,
Cc

0.
C- for reduc-

tion of hin

to bin
C- for reduc-

tion of hn0.

to MnO
CO- from fixed

CO- produced
in Hearth &
carbon

Bosh
Op= from Fep0.

Up-"t rom, Blast
Ro- from
st

Bla
in Blast

Ho0~ in
Blast

H,
nb

c
Mni

x

8,

2609

483,466
90

0
402,076 B.T.U.

1,426
(4

22

gl

81,390 Total Heat

Heat absorbed in cooling Mn Vapor in Top Gas
Heat of vaporization from condensed Mn vapor

Total heat to shaft
Sensible heat in top gas (dry)

Net shaft heat

» ohO-

2.
219,570 B.T.U,

Total H & B Heat
Heat to Shaft
Net available heat


Heat Distribution - Hearth & Bosh .

B.T.U.
latent heat of slag formation (63.4 x 945) ~ 49,900 10,013
Latent heat of iron (110.5 x 126) 13,923
Reduction of 5% of Fes03 (Assumed) 17,000
Reduction of $i0, (2.3 x 4130) 9,500
Cooling water 29,300
Radiation and conduction (by difference) 22.975
Total 102, 711

Heat Distribution - Shaft.

B.T.U.
Heating coke to 2740°F (1504°C) 95,570
Reduction 95% of Fe,0, (0,95 x 105 = 3140) 313,494
Calcining limestone~(30.18 x 1830) 38,050
Heating slag materials to critical temperature 49,900
Heating iron to critical temperature (106.1 x 461) 48,900
Evaporation of water in charges 20.6 x 1092 24,480
Radiation etc (by difference) _ 69,187

637,581

From the above heat balance it is apparent that togmelt 110.5 1b. of
iron of this grade, in the time specified, requires 102,711 B.t.u. at a tem
perature of 2740 F (1504° C) or more. It is also logical to assume that any
change in furnace operation, such as the addition of oxygen to the blast which
will increase the available heat in the bosh section, will increase the smelt-
ing power of the furnace in direct proportion to the additional available
heat. On investigation of the thermal possibilities of enriching the blast
in this particular practice with oxygen, we have obtained the following figures
of availeble hearth or smelting heat and temperature, which are also shown
graphically on the attached curves:

Hearth heat available Increase Temp.available at

Blast by weight above 2740°F (B.t.u.) (4) tuyeres (°C)
Natural air at 382°C 102,711 1917
05 % Not(ary at 15°C)

36 7 124,855 al 1849
40 60 188,589 83 2222
50 50 226 945 lel 2545
60 40 254,492 145 2815
20 30 270,792 163 3049
80 20 284,481 177 3254
90 10 295,168 187 3435
100 303,659 195 3596

-10-


Heat Distribution - Heurth and Bosh.

B.T,U.
Heat to reduce NnOp to Mn 184,300
Heat to reduce MnO, to MnO 10,200
Latent heat of fusion of Mn & heat in metal at 3200°F 42,600
Reduction of Sid. 8,600
Letent heet of fusion of slag 86.2 (1080-985) 7,847
Totel heat in MnO 18,079
Latent heat of vaporization of Mn 0,82 x 33,312 27,317
Radiation and conduction (from previous figures) 30,514
Total heat requirements 3,457
Heat Distribution - Shaft
B,T.U.
Heat to reduce Fe203 9.6 x 3142.8 30,171
Heat to raise C to criticel temperature 123,840
Heat imparted to slug forming materials:
Si0p 23.5 x 0.3209 = 7.284
Al abs 7.9 x 0.3633 = 2.870
CaO 833.5 x 0.2995 =_10.033_
20.187 x 3140 63,777
Heat to raise Mn to 3200°F 146 ,989
Heat imperted to iron - including latent hest 6,363
Radiation (by difference) 6 337
Total heat requirements 377,077

The figure allowed for shaft radiation appeurs smell, but we must
consider that we are going to heve low top temperatures. What mey happen is
this! We may have a lower top temperature than 400°, then the difference in
sensible heat of the gases will incresese the radiation, Also we sre sure we
will heave a greeter condensation of mengunese vapor in the shaft with its con-
tribution, so thet taking 411 of these factors into consideretion our shaft
heat will be emple for this process,

To form # comparison of manufacturing costs of the proposed process
to thet in use toduy we have prepared the following cost estimates based for
the greater part on actual operating costs. We are charging oxygen at a rate
of $3.00 per ton, for we have been assured that for large commercial produc-
tion the cost of oxygen will herdly exceed this figure.

47


7, ‘In addition to the above, it is believed that the sulphur
content of the iron would be reduced by this practice, or,
in other words, that we might use a coke higher in sulphur
than is today possible.

BESSEMER PROCESS FOR THE MANUFACTURE OF STERD

Another field for the application of oxygen or oxygenated air is in
connection with the Bessemer process. This process depends for its operation
on the fact that when molten pig iron is subjected to the action of numerous
jets of air blown through it, the impurities of the iron,-carbon, manganese,
silicon, and in some cases, phosphorous,- are oxidized, leaving nearly pure
iron as a product. The heat for this process is supplied through the combus-
tion of these impurities by the oxygen of the blast.

The Bessemer process is divided into two major divisions, namely, acid
and basic which are so designeted from the character of the resultant slag.
In the acid process, cardon, manganese, silicon, and some iron are ordinarily
oxidized; but owing to the acid nature of the slag, no phosphorus is eliminated
from the bath. In the basic process, all of the foregoing elements are removed
together with the greater portion of the phosphorus. In fact, in the basic
process, the cxidation of phosphorus contributes a large percentage of the
total heat, and the process is not possiole with irons containing less than from
1.5 to 2.0 per cent of phosphorus, the best results requiring between 2.5 and
3 per cent. This fact in itself has prevented the application of the basic
process in the United States, because our iron ores have a lower phosphorus
content than is necessary to make the required grade of pig iron,

We have, however, available what might be termed intermediate ores,
which, while they do not contain sufficient phosphorus to make the basic
process possible, still the amount of this element is too high for use in the
acid converter. If, however, the heat requirements for the process might be
lowered below those of standard basic practice to correspond with the lower
phosphorus in the pig iron availeble, we would have a process which would
utilize these rather unsatisfactory products to our advantage, sécuring a
steel better in quality than that obtained by the acid Bessemer process, and
as a by-product a high-phosphorus slag valuable for fertilizer.

Thermal Requirements of Bessemer Process.

At this point it is well to look in to the thermal requirements of
the Bessemer process in general, with a view to the possible application of
oxygen and its probable effects:

A. Heat available during the blow:

1. Heat in the body of converter at start.
2. Heat in the molten pig iron used.

3. Heat in ary molten additions, such as ferro-manganese.
4, Heat in blast (if warm)

5. Heat developed by oxidation of the bath.

6. Heat develoned by formation of slag.

-18-


Assuming 4.66% of carbon in ash es before:

Carbon gasified per 1b. coke, lb. 0.895
Coke consumed per 1000 cu.ft. of gas, lb. 33.96
Steam decomposed during period, 1b. 178.1

Steam per 1000 cu.ft. of gas, 1d. 25.23

Assuming 8 1b, of stewm per 1b. of coke:

Additional coke for steam per 1000 cu.ft. of gas, 1b, 3.15
Total coke per 1000 cu.ft. of gas, lb. 37,114

Net calorific value of gas, B.t.u. 283
Now, by comparing requirements for the three processes, we mey strike
the following rough comparison of costs, using coal at $7.00 per 2000 lb.

delivered, coke at $11.00 per 2000 1b. delivered, and oxygen at $3.00 per 2240
lb.

Comparison of costs per 1000 cu.ft. of gauss

Coal Oxygen _: Total B.T.U. Cost per
Lb. Cost Lb. (ost : Material per 1000
2 Cost cueft.  B.T,Us
|
Streight |
Producer 19.391 0.0678 $0.0678 221 $0,000307
Tater gas B7.114 00,2041 0.2041 283 0.000712
I
Oxygen |
Process B3.12 0.1159 «6.7 0.009 0.1249 400 0.000312

From a straight city gus standpoint, the gas made with oxygen will not
only be of greater celorific value than water-gas, thus requiring less enrich-
ment, but will cost less. It is our opinion that a ges of 400 B.t.u. could be
used for this purpose without eny further enrichment and the saying in this
case would be much greuter.

On comparing with the producer ges we find that the cost per cubic
foot of "oxygen made" gas is greater; but inasmuch as the heating value of the
new gas per cubic foot is nearly doubled, the value as a fuel will be even
greater than twice that of producer gas. It was really from a fuel standpoint
that the qestion of gas was first considered, and this study is submitted more
to show the progress which may be expected along lines using very low-grade
fuels in producers to make a fuel gas. We can not predict by calculations just
how far we could go in this field, or whst fuels we would be eebled to use for
making gus; but we feel that experimental work should be started as soon as
possible slong this line.

~36-


The work of the Committee is divided into two parts, as follows:

1. Study of present day processes for the production of oxygen in
order to determine the feasibility of attempting to produce oxygen, or oxy-
genated wir, in such amounts and at such a cost as to permit of its use in
metallurgical operations.

2. A study of the feasibility of using oxygen, or oxygenated air,
in metallurgical operations in order to increase the efficiency of same,
and thus bring about the production of metals at a lower cost and possibly
the use of lower grade ore.

Both studies are being carried on simultaneously and the Committee
is divided according to their specialties and assigned to that phase of the
above work to which they are especially fitted.

Study No. 1: Sub-Committee is composed of the following members!

Dr. R. B. Moore

Dr. R. C, Tolman
Prof. W. L, DeBaufre
Mr. J. W. Davis

Mr. M. H. Roberts

Study No. 2: Sub-Committee is composed of the following members:

Drs D. A. Iyon
Dr. F. G, Cottrell
Mr. F. W. Davis
Mr. Frank Hodson
Mr. P. H. Royster
Dr. H. W, Gillett

The Sub-Committee on the metallurgical operations has been making
a study of the probable effects of oxygen enriched #@ir in present day
metallurgical processes, showing the effects to be expected on operating
efficiency, quality of product and manufacturing costs. Along this line
studies have been made of the following processes including recommendations
as to the possible limits of oxygen content of the air used?

1. Blast furnace smelting of iron.

2. Bessemer process for the manufacture of steel,
3, Open-hearth process for the manufacture of steel.
4. Mamfacture of artificial gas.

5. Blast furnace smelting of ferro-manganese.

In addition to acting es Secretary to the Committee, Mr, F. W. Davis
has presented the following report of the above mentioned study which has
been approved by the Committee as a whole.

Respectfully,

D, A. LYON,
Assistant Director in Charge of Research.

-2


Air for combustion .

Lb. gas Specific heat Tb.-cal,
Og 23-8804. (0,2104+0,0000187 (26)) 26 - (0,2104+0,0000187 (15)) 15 =
5.4834 - 3,1605 = 2.3229 5.5
Nz 7-4412 — (0,2405+ 0.0000214 (26)) 26 - (0,2405+ 0,0000214 (15)) 15 =
6.266 - 3.612 = 2.645 19,0
H,0 0.1085 (0,424 0,000185 (26)) 26 - (0,42+0,000185 (15)) 15 =
2 11,0422 - 6.342 = 4.7002 _0.5
Total heat in air above 15° 26.
cal.
Heat of combustion of gas 7,070
Sensible heat in kas 351
Sensible heat in air 25,
Total heat to furnace 74446

Heat carried from furnace as sensible heat in products of combustion

(T = 1550°C)

Pounds Specific heat
leery 2.5229 0.3605 0.9095
Og 044452 0.2394 0.1066
Np 7.1412 0.2737 1,9545
H,0 1.3567 0,7088 0.8176
3.7882 % 1535 = 5815 cal.
Cal.
Total heat to furnace 7,446
Total heat curried from
furnace 5,815
1,631

Temperature of flame

2.5229 (0.19+0,00011 t ) t+0,4451 (0,2104+0,0000187 t)t+7.1412 (0.2405
+0,0000214t) t+1.1567 (0.42 + 0.000185 t )t - 7446

ts: 1864 °
Temperature - 1879 C


wir through stoves 31% 02 dlast-no_ stoves

lb. per cost cost per lb.per cost cost per
ton per _ton ton iron ton _per ton _ton iron
Iron ore 3973 «=6$ 6,00 = $10,638 «= 3973. «S$ 6.00 = $10.638
Coke 2027 10.00 10,130 1717 10.00 8.585
Limestone 993 1.25 2554 572 4,00 1.021
Labor? (cal cined)
Supt., firemen, etc. 047 0.038
Stocking 010 O10
Charging +106 +106
Casting +253 +204
Other producing labor 009 009
Repairs and supplies +459 +372
Steam -004 003
Blowing 400 2239
Water 030 073
Hydraulic power and pneumatic power 009 2007
Electric light and power O15 «012
Yard switching 291 «21
Handling material +200 «200
Chemical laboratory 023 019
General works 044 +036
Safety and welfare «006 +005
Contingent fund +010 »008
Relining fund and depreciation +650 +526
Interest on Investment 688 +583
Oxygen 572 +762
Gross total cost 24.636 23.747
Credit for surplus gas, 97,883 cu.ft. 98,865 cu.ft.
at 2a¢ per 1000 1,958 at 2.3¢ per 1000 2.274
Credit for stoves (see note) . 1357
Total credits 1,958 2.631
Net cost per ton 22.678 21.116
saving per ton 1.562
6.7%
358 tons per day 422 tons per day
18% increase
(Cost of stoves $500 , 000
(Depreciation per year 5 per cent
(Int. on investment 6on nt
{rearly charge 55,000
Yearly tonnage 154,030
(tearge per ton 0,357

Utilization of Oxygen to prevent Chilling or Freezing of Hearth Zone.

There is one item which is not included in the cost estimate but which
will be a big factor in the saving effected by having oxygen available, and it
is this: All of our furnaces are using more coke per ton of iron than the actual
minimum amount required, this additional coke being their insurance against

~15-


In order to obtain some rough idea of cost comparison, the present
low-carbon open-hearth steel requires as fuel 600 1b. of gas coal per ton,
which at present costs $7,50 per net ton delivered, or a fuel cost of $2.25
per ton of steel. With the proposed basic Bessemer process along the lines
shown in the heat balance we would require 0.0448 ton of oxygen per ton of
steel, or with oxygen available at $3. per ton, a cost of 13.44 cents for
oxygen per ton of steel.

Application of Oxygen to the Open-Hearth Process for making Steel,

It is with much hesitancy that we approach the subject of the applica-
tion of oxygenated air to the Siemen's-Martin or open-hearth process. This
is due to the fact that while this process represents the greatest develop-
ment in quantity steel production to the present time, still it is a process
in which the thermal efficiency is very low. While the applicetion of oxygen
will effect economies, still we rather feel that the more obvious defects of
the process should first receive consideration. Little authentic detailed
data on open-hearth operation are availeble to render an accurate analysis to
be made of the various short-comings of the process. Two notable exceptions
are found in the article "Heat Balance of the Open-Hearth" by Cornell*, and
a paper presented before the British Iron and Steel Institute, entitled
"British Siemen's Furnace Practice, "by Clementet* Both of these papers show
the thermal efficiency of the open-hearth process to be less than 20%, ‘The
last-named paper is of particular interest in that the writer thereof has made
rather umsual measurements of temperature and gas velocities, which have
enabled him to designate the point in the process at which different components
of the totel heat losses occurred, as follows:

Heat Losses from Siemen's Furnace.

Per cent of total

heat loss.
Heat radiated from bath and port ends 44.20
Heat radiated from gas regenerators 9,39
Heat radiated from gas flues and valves 1.97
Heat radiated from air regenerators 6.11
Heat radiated from air flues and valves 1.30
Heat radiated from chimney flue 0.83
Heat loss in chimney gases 36.20

The largest and most striking figure in the above summation is that
of heat lost by radiation from the bath and port ends, This figure impresses
us as a most forceful argument as to the truth of a conviction we have had
for a long time, that is, that the oper-hearth process stands in vital need
of a new and what we might term a "super-refractory." The silica brick used
for the roof and port ends of the furnace is the purest obtainable, and while
it_is the most suitable material available, it is in our estimation far from
* Cornell, Sidney, The Heat Balance of the Open Hearth: Met. & Chem. Eng.,

vol. 11, 1913, pp. 257-266.
** Clements, Fred, British Siemen's Furnace Practice: Trensactions British
Iron & Steel Institute, May, 1922.

-2l-


of this free sulphur vapor is independent of the amount of sulphur contained
in the coke, the avowunt of sulplur absorbed by the iron will be independent
of the sulphur content of the coke, but proportional to the speed with which
the ferrous sulphide formed at the surface diffuses to the center of the iron,
During a discussion* of this paper, Mr. Powell stated that the absorption of
sulphur by the iron will also be proportional to the length of time the iron
is subjected to the action of free sulphur vavor in this zone, or that the ab-
sorption of sulphur by the iron is inversely proportional to the velocity cf
the iron in passing through the spongy zone, Now, as we increase the oxygen
in the blast, we are increasing production and hence decreasing the length of
time that the iron will be in the spongy state. In the particuler example
previously given, we will increase the speed by 18 per cent, which should re-
duce the sulphur content of the product by 18 per cent. This is a factor of
great importance for not only will it enable us to produce an iron uniformly
low in sulphur, but it will also make available large quantities of coke whose
high sulphur content prohibits its use in present-day practice.

Results to be expected from use of Oxygenated Air,

On the whole, our study of this problem has firmly convinced us that
with the application of oxygen to the present blast-furnace we will accomplish
the following results:

1. Decrease of production costs?

a. By increasing the high temperature or smelting heat
available per unit of fuel,

b. By removing the necessity for charging more coke than
is theoretically necessary,

¢. By rendering hot blast unnecessary, and reducing the
initial investment by the cost of hot-blast stoves,
at the same time releasing for other use the gas con~
sumed for this purpose.

2. Increase in the present output per fu-nace.

3. Increase of flexibility of the process, by’ giving the operator
@ remedy for any irregularity or trouble occurring in the hearth
and bosh section,

4, Increase in uniformity of product, oy sdmitting of mmch closer
chemical control.

5, A change in the limiting factor of the process from the in-
accessible hearth and bosh section to the shaft section.
This will mean that in the new process, any economy accom
plished in the shaft section will be effective in increasing
production and efficiency.

6. Make possible the use of cheaper materials, ore of a lower iron
content, and coke higher in ash.
* Discussion by F, W. Davis, and answered by Mr. Powell at the Merch 1923,
meeting of the American Institute of Mining end Metallurgical Engineers, This
will appear in the 1923 Transactions, but as yet is not published.

-17-


Heat in gases at exit from boiler (220°C)

Pounds Specific heat
Os 2.522% 0.21429 0,541
0. 0.4451 0.2145 0.095
xg 7.1412 0.2452 1.751
HO 1.1567 0.4607 02533 _
2.920 x 205 = 599 cal.
Cal.
Heat entering boilers 5815
Heat leaving boilers 599
Heat absorbed ty boilers 52l6
Heat in Heat in Heat in Total heat in gas
furnace boiler flue-gas per 1b, of coal,
Using air throughout 4844 66.4% 1335 18.6% 697 7293
Using Og in gas producers;
no regeneration 1631 21.9% 5216 70.0 599 7446
Or in terms of total B.t.u. in coal and steam
Totel heat Heat to Heat to Total heat
furnace boiler utilized %
Using air throughout 7643 «= 4844 63.4% 1335 17.56 80.9
Using 0 in gas producer 7730 1631 21.1% 5216 67.5 88.6
2

Conclusions regarding the Thermal Problems in the Open Hearth,

While these figures show a saving in total heat recovered, they are
not attractive in that while more heat is utilized on the whole, it is used
mainly in the manufacture of steam, which is a by-product of this process, and
very much less heat enters the bath or primary product than in present practice,
However, if we are enabled to secure a refractory roof which will withstand the
higher temperatures, we will then be in a position to decrease further the
nitrogen in the flue-gas and in this manner change the ratio of useful heats
to that of current practice, with the result thet we will have 4 much more
rapid process and a smaller first cost by virtue of having no regenerators.

Available Fuel_in Open-Hearth Process.

Another phase of the qestion of the use of oxygen in the open-hearth
is found in the matter of available fuel. The ordinary process requires for
success large volumes of gas made from the most expensive grade of industrial
coal, but we feel assured that suitable gas can be manufactured from much
cheaper material by the aid of oxygen, and in this line it is well to consider
blast-furnace gas. This fuel is unsuitable for open-hearth work because it is
a low-calorific, slow-burning gas, practically devoid of illuminants. Buming

-30-


end it would be necessary to recirculate a portion of the top gas. It is
estimated this would increase the tonnage by 41 per cent and decrease the coke
consumption by 30 per cent. However, in view of the fact that due to the
deficiency of carbon monoxide in the top gas circulation of this gas would be
necessary, the conclusion was reached that for the first demonstration it would
be well not to make any changes that would prevent the burden being reduced com-
pletely by one passage of the furnace gas. We can, however, decrease the shaft
requirements to the extent of charging calcined limestone, which will, of
course, increase the limit to which we may go regarding the reducing power of
the gas. We can also eliminate hot-blast stoves, supplying wind at atmospheric
temperature.

After carefully considering the matter, it was concluded that in this
perticular practice, 31 per cent of the oxygen in the blast will be as high
as it will be practical to go, and that this mixture, when charged to the
furnace cold, will increase the production of the furnace by 18.0 per cent and
decrease costs 6.7 per cent.

Tke heat values involved are as follows:


temperature. Some time during the first half of the 15th century an attempt
was made in Germany to utilize the heat of these waste gases for preheating
the charge, which led to the development of the first shaft or blast-furnace.
One may see here even in the earlier development of the art that the process
was being shaped to accomodate combustion with air or a mixture containing
about 77 per cent by weight of inert matter, the shaft of the furnace being
used to reclaim part of the heat carried off in the large volume of gas.

In the following history of the process from this earliest work to the
present time, one can not fail to note the astonishing fact that while many
revolutionary changes have been effected in the mechanical side of the process,

the metallurgical side of today is almost identical with that of the ancient
Germans,

Increasing the Oxygen Content of the Blast,

The matter of increasing the oxygen content of the air blown into the
iron blast-furnace has probably received more discussion than any other pro-
posed metallurgical application of oxygen. The fact, however, that oxygen has
always been an expensive commodity hag done much to prevent any real analysis
being made of the effect of this practice, so that published opinions, being
opinions only, differ greatly from one another as to the ultimate result pre-
dicted. However, by a careful analysis of both the metallurgical and thermo-
dynamic principles involved, we may predict with some accuracy the effect on
furnace operation of any change of this character.

For a comprehensive study we must first consider the furnace itself,
and the principal chemical reactions which take place therein. In every blast
furnace there are two main sections, namely the hearth and dosh sections, and
the shaft section, each of which has a separate and distinct function to per-
form. The burden or charge as it passes down the shaft section, is heated by
the ascending hot gases; the limestone is calcined, and the iron oxides are
reduced to a large extent to metallic iron by the action of the hot carbon
monoxide. All of the chemical reactions of the shaft section are performed at
a comparatively low temperature. In the hearth and bosh section, the slag-
forming materials are melted, the silicon is reduced, and the remaining iron
oxide is reduced; in other words, the actual smelting is performed in this
hearth and bosh section, and all of the work mst be done at a very high
temperature. Therefore, these two sections of the furnace must be considered
as two individual units, the shaft as the preparatory zone, and the hearth and
bosh as the actual smelting zone.

Thermodynamic Principles in Smelting.

With this idea of the division of work performed in the furnace, it
is well to consider the thermodynamic principles involved. The first and
second laws of thermodynamics apply to the blast-furnace just es much as they
do to the steam engine, and for our purpose they may be stated as follows:

1. The quantity of work produced by transformation of heat bears a
definite and unchanging ratio to the quantity of heat transformed.

2. The proportion of any given quantity of heat which can be utilized
for conversion into work depends upon the temperatures at which the heat is
applied and discharged.

—


Total Oz
Og in gs

Og from air

23% excess 02

Og total from air
H. from air

Hg0 from eir

Combustion data per pound of coal

Products of Combustion .

Tb. of Gas Lb.of 0 for ive) HOON, co}
Combfist ion 2 2 2 2
1.0288 0.5879 1.6167
0.0867 0.3468 0.2384 0.1951
0.1343 0.4605 0.4221 0.1727
0.2456 -- 0.2456
0.0537 0.4296 0.4833
9.0196
12-9673 1.9673
0.0508 _ 0.0508
1.8248
0,0196
1.8052
0.4152 _ 4152
2.2204
71,3917 7.3917
0.1124 Q,1124 _
2.5328 1.0143 9.3590 .4152

Assuming the gas to leave regenerator dt 1108°C,, the sensible heat
of gas above 15° is as follows:

Specific heat

0,2405 +0,C000z14 (1108)

Lb. Gas
co 1.0288
CHa 0.0867
Coy 0+1343
Cg 0.2456
He 0.0537
Og 0.0196
Ng 1.9673
Hz0 0.0508

0.38 + 0.00023 (1108)
0.46 + 0.0003 (1108)
0.19 + 0.00011 (1108)
3.37 + 0,0003 (1108)

0.21044 0,0000187 (1108)
0,2405+ 0,0000214 (1108)
0.42 + 0.000185 (1108)

enn tw a

0.2642
0.6238
0.7924
0.3119
3.7024
0.2311
0.2642
0.6250

Tempevaturs
vist... Cel.
1093 299
1093 59
1093 116
1003 84
1093' gi?
109°3 5
109% 870
109% Py

1385

Air leaves the regenerator at 1304°C,, and the sensible heat of the
air per 1b. of coal is as follows:

Lb.
02 2.2204
No 7.3917
HO 00.1124

Specific heat Temperature
rise
0,2104+0,0000187 (1304) 1289
0.2405+0.0000214 (1304) 1289
0.42 + 0,000185 (1304) 1289

Total heat to furnace per 1b. of coal.

Cel.
Calorific value of gas 6707
Sensible heat of gas 1385
Sensible heat of air 3325
11417

-27-

Cal,
673
2557

“3325


Assume the moisture in the coal as pussing unchanged into the gas,
and «all hydrogen in dry gas mist have coma from hydrogen of coal and decompo-
sition of steam; ena we find the hydrogen per cu.ft. of ges to bet

Hy in Hp 0.176 x 0.09 oz.
Hg in HsS 0,002 x 0.09

Hg in CHy 0,036 x 0.18

Hp in Cp Hy (0.032 x 0.18 _—
0.02825 oz,

0,00177 1b.
Hydrogen in gas per 1b, of coal = 0.00177 x 53.83 = 0,0953
Hydrogen per 1b. of coal from coal 0.0560_
Hydrogen per 1b. of coal from steum 0.0393

Weight of steam decomposed per lb. of coal = 0.0393 x 9 = 0.3537

Weight oO, in gas per 1b. of coal

No in gas = 1.967339
Ng from coal = 0.02

Ng from aire 1.947339 1b.
Op from air = 0,584961 1b.

Now let us assume that we substitute pure axygen for the air blast now
used in producer practice, which will relieve the producer from heating the
nitrogen of the air to 1050°C (Temperature of gas at top of the producer),

Heat conserved by eliminating nitrogen

Specific heat of Np = 0,2405+0,0000214t witht = 1050°C Specific
heat = 0.26297 1b. cal.
Heat conserved = 1.947339 x (1050 -26:0) x 0.26297 = 524.38194 1b.-cal.

If this heat is assumed to be absorbed by decomposition of steam:

Heat necessary to decompose 1 1b. of steam = 3196 lb.~cal,
Heat absorbed ty Hg of decomposition
0.111 x 3,685 x 950 =__388 1b.-cal.

Total extra heat absorbed per 1b. of steam 3584 1b.-cal.

HzO decomposed by 524.3819 cal. = 524.3819 = 0.1463 1d.
3584

Op from steam 2 8/9 x 0.1463 = 0,13
Og required for this process per 1b. of coal = 0.584961 - O13 = 0.454961 1b.

-24-


THE USE OF OXYGEN OR OXYGENATED 4IR IN
METALLURGICAL AND ALLIED PROCESSES.

Report of the Committee
By F. W. Davis.

Introduction

In the past it has been considered essential that our higher grade
raw materials should be utilized in the manufacture of many products,
especially in metallurgical processes, but now that we are confronted with
diminishing supplies of such materials, we have been forced to use what
were once considered undesirable and practically valueless. This condition
will become more accentuated as time passes, and we have got to meet it by
improving methods so as to utilize the lower grade supplies; and make e pro-
duct as good and as cheaply and efficiently as from the richer materials.
With each development of this character we are not only conserving our re-
sources by eliminating waste, but we are also increasing our reserves by
the quantity of lower grade material which responds to such improved methods.
For instance: by eliminating impurities from fuel end iron ores we are
enabled to work beds of such materials once condemned as unsuitable for any
purpose. .

The trend of development in smelting and refining is in the elimime-
tion of inert matter - that is, materiel (solid or gaseous) that does not
enter into the reactions in the furnace, and which simply passes through,
absorbing end carrying away heat and reduced metals therefrom, @ heat that
otherwise would be utilized in the process. For instance, in making iron in
the blast furnace, a process is still employed in which the inert material
greatly outweighs the active material, as can be illustrated by the fact
that in the production of one ton of pig iron three tons of nitrogen is
passed through the furnace, The same is more or less true of all furnace
operations which derive heat from the combustion of fuel by atmospheric air.
It would seem, therefore, that metallurgical technique, as well as the con-
servation of our natural resources, would be greatly advanced if the nitrogen
passing through the furnace could be diminished, This might be done by sub-
stituting oxygen, or @ mixture of oxygen and air, for the air now used, end
the following discussion shows the possibilities of the application and
efficiency of oxygen to some phases of ferrous metallurgy as it exists today.

POSSIBILITIES OF APPLYING OXYGENATED AIR.
No claim is made that this is a new or novel idea, because the possi-
bilities of using a higher oxygm mixture for combustion have been discussed

by eminent scientists for the past 15 or 20 years; and the consensus of
opinion is that great economies would result from such a process. Moreover,

-3-


New York City, N. Yes

Joly 20, 1923.

Mr. D. A. lyon,

Asst. Director in Charge of Research,
Bureau of Mines,

Washington, D, C.

Dear Mr. Lyon:

T am transmitting herewith the report of the
Committee on the Use of Oxygen or Oxygeneted Air in
Metellurgical end Allied Processes, This report has
been specifically written ty Mr. F. W. Davis and has
received the approval of the entire committee.

Very truly yours,

M. H. Roberts,
Consulting Mechanical Mgineer
and Chairman of Committee.


18% INCREASE IN BURDEN,

MAKING PIG IRON, USING 31% DXYGHIN BLAST (by weight) AND NO STOVES.

Cs

BLAST FURNA!

53.2

sey JO ouMTOA %
“ZI 009

qe sep “yz “NO
‘abe yseus

09 4eOy TRyZ0y,

Bo
‘0 BT.U.

6924078 B.T.U,
T)
t

my
ai9

: 3
“HE'a yeUs OF ~
@PH WoL Yeo 1

: a

42, 708
Sensible heat in gas

Net shaft heat

cI
: : fo}
“DLE seq a sg
doy Ut yeaH bd a a

Shaft

a
“at ‘azeus i Fyw sey
eeseesesee AA Sakhalin eee Sa a SRR See R'3

as
"SsQT a 8

wo Ww
“nae we &
sey £q wotqzoes cow -
@PH WOTT pats ma

305,548 B.T.U,

“Aba ‘9txe
qe ‘qt zed yeayq

fe}
iene: s & fA
ysog P YyIvEH iS
03 yeOy T2903,

160
420,285 B.T.U,

5us
114,737 BTU,

ated uotysnqg
-wo0o Jo yvoyq

Hearth and Posh

aouerque 42 2
“qt sed yeoq in
w
oN

G, saver yay ee
4e amyereduay, 3S s gz 8 3
iv)

84.5
88,0

ut “QT

Total Heat to H&B
Net Available heat

Heat to Shaft

Fe203
o- for C burned
2

one

Item

- Oxydized by Net Oo

ast (Dry)
- total
from Blast

(Moist)
- from H20

in Blast
O- remaining

COp- from CO+0
‘o- from St
total

oo
=

- from

4
2

3
3
)

Hp20- in Charges

Oo- from

ie}
SO- in Hearth Gas

duction of Si
C= total to
Oo- from H20
in Blast

Oo~ net for CO
22)

C- in Iron
Hearth

& lost in
Hearth

C- for re-
C~ burned

in Shaft

CO- pro-

duced in

Hp0- from
Blast

in Shaft

C- burned
Hp

by Oo of

Blast
C- total

charged
Hearth &
No- from
Blast

Bosh



The Sommittee has developed plans for experimentally determining the
effects of oxygen enriched air upon the operation of the blast furnace, and

it recommended that these plans be put into effect as the first step of an
extended research upon the general applicability of oxygen to metellurgy.

To show the findings of the committee and its studies in detail
would require lengthy and tedious calculation, which, for brevity, will be
emitted: However, certain studies of the application of oxygen will be
presented, which, while they do not necessitate radical changes in present
equipment, still show such savings as to warrant further investigation.

It must be remembered, however, that these are only introductory studies in
which we are limited as to the possible advantages to be obtained by the
fact that we are using equipment designed to use air with 77 per cent by
weight inert matter, namely, nitrogen.

The savings and refinements given later refer only to the major pro-
cesses, no mention being made of the value to any iron or steel plant of a
supply of available oxygen for miscellaneous purposes, such as for cutting,
welding, etc. We are inclined to believe that oxygen as generated for a
blast-furnace or open-hearth furnace would find many sundry uses around the
plant, some of which can not be predicted today; but in the aggregate, this
use would result in a great saving when comparing the cost of compressed
oxygen with that of oxygen made direct, and simply piped to the point of
consump tion.

While this report is strictly one on ferrous metallurgy, our files
show great economies in the metallurgy of zinc. Copper has not been studied
in detail yet, but promises to show similar economies to those for zinc. In
fact, we feel that all non-ferrous metallurgy will be benefited by the use
of cheap oxygen. The ceramic industry will also be made more efficient,
especially in the manufacture of super-refractories, which require very high
temperatures.

The metallurgical calculations in the report follow as nearly as
possible accepted theories of the process involved, and the results of these
calculations agree with practical operations where present processes are con-
cerned. But while the general results do agree with practical conditions,
we believe that some of the actual reactions involved may not exactly cor-
respond to the theories as given here. However, we did not care to introduce
any new theories until we have a better understanding of these reactions.

APPLICATION OF OXYGEN TO THE SMELTING OF IRON.
Historical,

In order to give an idea of what will be accomplished in the smelting
of iron ore in a blast furnace, by the substitution of a mixture of air and
oxygen for the air blast now in use, it will be well to describe briefly the
development of the present process, as well as the manner in which it functions,
Iron was first produced by the reduction in forge furnaces of oxide ores by
solid carton. This was e slow process, and one extremely wasteful of fuel, as
the large volume of gases produced was given off to the atmosphere at a high

-5-


B. Heat distribution:

7, Heat in body of converter at finish.

8. Heat in finished steel.

9. Heat in slag.
10. Heat utilized in heating O_ of air to temperature of bath.
11, Heat utilized in heating we of air to temperature of bath.
12, Heat in fumes.
13, Heat absorbed by decomposition of H20 in blast.

14. Heat to separate constituents of bath,
15, Heat loss due to all radiation and conduction.

. In going over the thermal possibilities as shown above, the two items
which might bear investigation most are No. 11 and 13, the latter, however,
being of such small magnitude that it is hardly worth consideration at present.

Rather than go into complete heat balances, which of necessity would
be lengthy and complicated, we will simply compare the heats with which we
will be concerned in this investigation - namely, those heats generated and

dissipated by the blast in @ simple problem taken from recognized successful
practice, as follows: i

4 30,000 1b. basic sonverter in a blow eliminates 0.50 per cent Si,
1.60% Mn, 3.50 per cent C, 2.50 per cent P, and 3,00 per cent Fe. With the
temperature of the blast at zero °C and the average temperature of the blow
at 1500°C. the heat balance of the process is as follows;

Heat balance in a basic converter.

Lb. calories Oxygen Nitrogen in

Chemical Reaction developed required blast, 1b.
lb.

ap +S 0, 750 1b, P 4,420, 000 968 3, 222
Si+ Oo 150 1b, Si 950,000 169 563
2Mn+ O05 = 2Mni 480 1b, Mn 794,000 140 466
2C + Op = 2 00 1050 1b. © 2,552, G00 1,400 4,660
2 Fet+02 = 2 FeO 900 1b. iron 1,056,000 257 855
Totals . 9,772, 000 2,934 9,766
Heat required to raise O, to temperature of reaction Lb.-cal.

(2934 x 1500 x 0.23845) = 1,049,418

Heat required to raise Nj to temperature of reaction
(9766 x 1500 x 0.2726) = 3,993,317

Total heat to blast 5,042,735
Gross heat developed by chemical reactions 9,772,000
Heat absorbed by blast 5,042,735
Net heat developed by blow 4,729,265


metadc38375



In making studies on the effects to be expected on the enrichment of
the blast we first tried to follow the scheme worked out for the iron blast-
furnace, one of the first steps being the elimination of hot ast stoves.
However, with the decrease in nitrogen necessary to accompl this we found
that we were making such radical chenges in the heat distritu‘ion that with
blust containing 31% of oxygen, and a 25% increase in turden, we would have
insufficient shaft heat to carry on the process. In the pig-iron process
the shaft heat is augnented by the oxidation of Fep0, of wu portion of the CO
gas present. If, therefore, we were enabled to oxidize CO in the shaft of the
Manganese furnace, we would supply the necessary heat. This might be ac-
complished by introducing either oxygen or air - preferably oxygen - to the
shaft just above the bosh. ‘The temperature at this point will be sufficiently
high for combustion, and we heve an over-abundance of combustible gas. One
feeture which must be developed, however, is a mewns of introducing the oxygen
in such » manner as to insure its union with the CO gas before meking contact
with the coke present. The following heat bélunces have been prepared on the
basis of this proposal, using a blast of 37.9% of Og, send increasing the burden

100%,

Material Balance for 37.9% o, Blast-100% increase in production.

Pounds To Metal To Slag
Coke Charged
Sido 6.5% 6.5 1b. Si 0.78 $i02 4.8
A103 3.0% 3,0 1d, 41293 3.0
ca0 4.5% 4.5 lb. a0 4.5
c 86.0% 86.0 3.6
Ore 184 1b,
$i0g 8.6% 15.8 1b. 610g 15.8
Fe203 8.5 15.6 Fe 11.0
Mn0g 58.4% 107.4 Mn 51.4 1b, Mind 13.4
1203 3,0 5.6 41203 5.6 1b
Limestone 76 1b, :
$103 7.0% 5.4 1b. Sid 5.4 1b
CaC0z ©: 93.0 70.6 1b. CaO 40,0 1d
Blast
Og 37.6% (ary) 75.1 lb.
No 62.4% 123.0 1d,
H20 1.8

-A2~


CHARGE PER 100 LB . CORE
Weight +: Composition : Weight : Pig : : :
: : charged : Iron ; Slag 3 Gases ¢
lb. =: 2 1b. 2 ibe 1b. 3 lb. os
Coke 7 (¢ 88.0 ¢ 88.0 +: 44 3 83.6
100 t (S405 5.33 5.30: 2 ($i0, 5.3 3
: (Cad 5.3 ¢ 5.3 3 2 (cad’ 5.3 3
+ (Hp:0 1.0: 1.0 3 : :H,0 1.0
Ore : (Fe90z 76.5 t 150.0 + 105.0: 0g 45.0
196 2 (936, 10.0: 19.6 1.1: (S10) 17.8 105 lez
: (Al 35 3.52 6.90 ¢ 2 (41203 6.86
: (#28 10.0 : 19.6: : : B20 19.6
Limestone : (CaO 47.6: 23.3 3: z (cad 23.3 3
4g = (MgO 4.8: 24 3: : (MgO 2.4 ¢
2 (S103 5.0: 25  ¢ (S103 25
= (C02 42.62 20.8 : : ! Wz 20.8
Blast + (Op 22-8: 100.5 2: : 20, 100.5
440.7 3 (Ng 76.13 335.4 3: : + NQ 335.4
: (B20 1-13 4.8 3 : 7 Hg «(0.5
Og 4.3

Pig iron, 110.5 1b. Slag, 63.4 1b.

Product per day, tons pie 5) 358

Temperature of blast, °F and °C.... 720 ~382
Temperature of top blast, °F and °C.. sees 538 -281
Heat in one unit of pig iron, cal.... sae 325
Heat in one unit of slag, cal....sseecsececneee - . 525
Cooling water heated per day through 50°C., gallon..............-+ 300,000

Assuming @ critical temperature of 2740°F (1504°C), which is consistent
with average practice, the following are heat belances of the hearth and bosh,
end shaft sections, respectively.

8


Johnson* has stated the second law as applied to blast-fumece
operation as follows:

“For every set of furnace conditions there is a critical tempera-
ture above which only certain necessary operations of this process
may be carried out. That is, the temperature necessary to melt the
cinder and make it sufficiently fluid to perfom its proper functions
is the critical temperature, since the slag must be brought to this
temperature, and the final reduction of the ore and probably other rev
actions must be performed by heat available above this temperature.
The heat availeble above the critical temperature is the total heat of
combustion of the carbon to carbon monoxide, plus sensible heat in the
blast, less the heat necessary to bring the products of combustion to
the critical temperature." To this should be added the sensible
heat of the carbon at the critical temperature.

The truth of this thermodynamic law as applied to the blast-furnace
has been demonstrated beyond question, first by the effect of preheating the
blast, and later by drying the blast. For instance, with the introduction of
hot blast, the fuel consumption of hard coal furnaces was reduced by more than
half, although the actual increase in totel heat was only about 18 per cent.

The application of air enriched with oxygen to the blast-furnace will ©
be accompanied to a more or less degree by a condition somewhat similar to
that effected by heating the blast ~- that is, the available heat for the high
temperature work of the hearth and bosh section will be increased, as with
each increase of oxygen we will have a corresponding decrease in the nitrogen
to be heated to the critical temperature, and this increase in heat will be
accompanied by greater smelting power of the furnace per unit of fuel and per
unit of time.

In heating the blast, we increase the smelting capacity or available
heat of the hearth and bosh without necessarily changing the heat of the
shaft. With the application of oxygen to the blast, however, we will decrease
the shaft or low-temperature heat as we increase the hearth and bosh heat,
due to the fact that we are decreasing the quantity of hot nitrogen flowing
through the shaft, The enriched gas, however, having a greater concentration
of carbon monoxide will have a greater reducing power per unit of carbon, and
we should expect to find that our shaft operation would be more efficient.

Calculations.

It is useless to theorize on the effect of any change in blast-furnace
operation without detailed calculations showing the action of the material
charged throughout the entire process. For that reason the following data
have been taken from a problem ty the late J. W. Richards** from a blast
furnace running on Lake Superior ore.

* Jobnson, J.E. Jr., Principles, Operation, and Products of the Blast
Furnace, 1918, p, 34

** Richards, J.W,, Metallurgical Calcmlations, Part 2, Problem 57, pp. 294-295.

-T-


With an understanding of the above conditions it becomes somewhat
easier to predict the probable effect of the addition of oxygen to the blast.
With a higher oxygen blast we will be able to increase the available high
temperature heat in the smelting zone, this increase being, of course, at the
expense of the lower temperature heat of the shaft. In this respect we en-
counter another point in which this practice differs from that of smelting
iron. When applying smell amounts of cxygen to the blast in the latter pro-
cess we were enabled to neglect to a great extent this decrease in hbat carried
from the bosh to the shaft because the reactions in the shaft section, namely
Feg0z plus 300 = 2%e plus 3W3, is sligh*ly exothermic, and as the extent of
this reaction increases by virtue of increased burden, it generates sufficient
heat to supply the deficiency in the shaft section, our limiting factor being
more chemical than thermal and being found in decreasing the 00 to CO
ratio. In the manufacture of ferro-manganese, however, we have very Little
Fe203 to be reduced, and the edditional heat imparted to the shaft section ty
this reaction is consequently very small. As our burden is increased to ac-
commodate higher oxygen blast, we find that the heat added to the shaft by
Feg0z is not proportional to the decrease in heat carried from the fusion zone
to the shaft, so that as we increase the oxygen we soon reach a yoint where
present conditions are reversed, and we have insufficient low- sature heat
for our preperatory zone. The chanics] composition of our ges will be little
affected, on account of having a smal! quimtity of iron oxide to reduce, and
very little of the CO will be converted to Wa It is possible that the problem
of deficiency in shaft heet may be solved by this gas rich in 00, because if we
have a heet deficiency ina streum of highly combustible gas, the natural solu-
tion appears to be to convert a portion of the potential calorific value of
the gas into heat by some form of combustion. This phase, however, will be
discussed later.

Considering the comparatively low efficiency of conversion of the
Manganese process, we have two greut sources of mangunese loss, namely, the
slag which carries a large percentuge of manganese and the gas which is rich
with mangenese vapor. The emount of mangenese in the slug increases with 4
cold furnace, so it is believed that manganese enters the slag only because of
a deficieng of hearth heat, and with the use of oxygenated blast we expect to
minimize this loss. Manganese is volatile at high temperatures, und en ap-
preciable amount is vaporized in the hearth and bosh section. This vapor is
carried in the gases, part of it is either condensed or held mechanically in
the shaft, and the remainder escupes from the top of the fumece. With a
blast of higher oxygen content we will operate with a cooler sheft, which
should facilitate a great condensation of the manganese vapor in this section
ands greater saving to the furnacé. Very little is known regarding the
relation between the manganese lost in the top gus and the totel mangunese
vaporized in the hearth and bosh section. Several operators consulted on this
matter geve estimates ranging from 12 to 25%, Fairly authentic figures of the
mangunese lost in top gus ure wt hand, and from these figures the total amount
of manganese vaporized must be estimated for the calculations following. In-
asmuch as the udvanteges shown for oxygen enrichment increase ws the amount of
total manganese vapor increases, a lower figure has been taken ‘hon these
estimetes would indicate, and it is essumed thet the manganese which eppears in
the top ges is a third of the total manganese veporized, the reeson for this
being that it is desired to leave no room for criticism. When assumptions are
of necessity mede it is desired that they be most conservative, and if they
are too conservative we will be pleasantly surprised in the result of the
experimental campaign.

-38-


Total potential heat in gas per 1b. of coal = 7,421 1b.-cal.

Now to determine the temperature obtainable with this cather imperfect-
ly mixed gas (excess oxygen) using pure oxygen at 15°C. for combustim:

2.5229 (0.19+0.00011 t) t 0.4451 (0.2104+.0000187t) t #o62(0.2405+0 .0000214t)
t + 1.0482, (0.42 =0.000185 t) t = 7421 cal.

0.000480187-t? + 1.018053t = 7421 cal
+2 + 2120 t * 15,460,417
t =» 3011 temperature = 3026°C

In the practice reported by Clements, the combustion temperature was
1803°C. It will now be a wimple matter to determine the composition of the ON
mixture necessary for combustim to attain this temperature without preheating
either gas or air. The air moisture given by Clements was 1.74 lb. of H,0 to
148 1b. of air, or 0.015 lb. of Hg0 per lb. of Nz; then each pound of atmospheric
Ng will absorb the following heat (assuming Nz at 15°C).

0.279 x 1788) + 0.0152 (0.7535.x 1788) ~ 518 cal.
Now let x = lb. of No ae
0.00048187 +2 + 1.018055 t + Sléx = 7421 cal.

t = 1788 _
1535 + 1820 + Slgx = 7421
slex * 4066
x 77.85

This gives us a mixture of 23.3 of 0.2 by weight, that is atmospheric
air will give the desired temperature without the use of regenerators, if the
producer is blom with pure oxygen.

For the purpose of comparing total heats, we are using temperature data
from Clements paper, such as, regenerator temperature, etc., and we will also in
both cases assume the fumace to be equipped with a waste-heat boiler that cools
the gas to a temperature of 220°C., which is considered good practice. First
consider a plant using atmospheric air throughout:

-26-


FERROMANGANESE PRACTICE;

BLAST = 37,9% Oo by WI,

NO STOVES, Op ADMITTED INTO SHAFT,

100% INCREASE IN PRODUCTION,

‘ Hearth and Bosh Shaft
A - : ' : > a j
g i8 shiz, :g $8 iS ise 0: 2 8 a ite Be 88 BL,
ho ies isis ifosie igs ise, i ig, & Se iSsidgi et ise ig 38
68 ix prasad i BERRI B Ue ig egSe igs iT ai4°8 ee om: 8s : 8a iS fo
me rPoltno: Pee ke Tee ieee oR ig aod Be 69g S9@ :3 . f, 38
Item aS ifSL AR SR. GA gd PRR IRS ES iat EB 2 Top Gas, Te q ibAp ite lai Dé ge id. is
a iesigeigse ( SRei Bd gg idsgo ed ag co re $ 53 32:83: 80 S28 35 eg
. t : : : : ; : da : : : ‘ toe ®O : : : :
agidaigaidsa i2aaiad i8 igadg isa igé is eiaig #8 Efi 8s (82 83 a8
Op- from Blast 74,1: 60 : 0 } i i i Pot ;
(Dry) i: | : ; Poi :
0,- total from : : : : Dot : :
Boast (Moist) 75,7 : : : : : toot : i
c- burned by Oo H : : : : i i
from Blast 56,8 : : 43755 : : Pot : :
C~ in metal yo: : : : foot : :
C- for reduction : : H : : i : :
of ind, to Mn 22,4 } : 4375, i : ot i
C- for’ reduction i : H pot :
of lindo to MnC = 2,2 } 2 4375-1 : : io :
C. for reduction : : : oy : i : : H
of SiO, 0.6 : : : 4375-—~ | 358, 750: : io :
G~ total charged 86,0 :3200: hho: £123, slo: : : : oo :
CO0-produced in i : : : : : i : : : H : : :
: : : : : : : : : : Pood : : : : ier, 387: 67, 387
H&B 191, i ! 3200 : 875: 167,387: 191,3: : : foot : : :
Jp~ from Blast 33 3 6: 0 i 3200: 875: 107, G25 } 333" : : 123} io i 123; 83.4 10,258; flor, 625 107,625 1664 36,€
450= in blast 1.8: 60: 0 : : : : boot Do : : : : : ;
do~ from HO : : : : : : : : : : ‘ : : H : :
2 H : H : : 4 : " : : : i H : + Ov
Ses 0.2 1.52250 -10,450! 3200 : 12290 2 WB 042! i ; 0.2; 1 2 | 1269 aah 2,58 256 3T; ON
ge from Hy0 : : : : : : : : : : : : ‘ : : :
in Blast 1.6 3 : H
Jom from Feo0 t 5.6 H : i
J0- from fixe : : : :
Jarbon H : 91,3: H i : :
O- : H i H : : :
fron Fe,0 * it i gn : 24375 | 355438:
e remaining i : : ! 183.2 : : : :
05= from CO plus : : : : :
05 i | : : i 12.7: i
-03- from limestone : : i 30,6: :
nOo- from Ore 107.4 j | 3200! a5 £165,826: : :
2 t H
\gr added above : : ‘ : :
mantle 25. vi : 25.7! : H : :
20- ized b i : : :
free by 45,0 | 2375 | 396 a5
CO- remaining 1138.2: 1,470: : : ost ay :
COp- total H1ah,o : 8,48 :

Total Heat to H&B
Heat from H & B to Shaft
Net Available heat

"637,966
6
360,496

277,470

hj

30, 443
Heat in Top Gas (sensi¥le)
Net shaft heat
Heat absorbed from Mn Vapor
Total

509, 183
4795340
4go, 766


Resultant Cas,

Weight in lb. per 1b. of coal.

Ho 0,053548 + 0,0163

1.02882
0.088718
0.134332
0.295566
0.069948
0.019634
0.026000

1.605008

% by weight
64.10
5,40
8.37
15.30
4.36
1.22
1.25

In the particular practice cited in Clemamts paper, ubout 23% excess

air is used.

Combustion data per pound ooal,

Lb.of gas Lb. of oxygen 0,
required
co 1.02882 0.587897 1.616717
CHy 0.086718 0.346872 0.2384745
CoHg 0.154332 0.460567 0.4221 86
COg 0.245566 0.245566
He 0.069948 0.559584

05 «0.016 24
Np 0020000
B30 0050800

H,0 Np Flue-gas
265229435
0,1951155
0.172713
0.629532
0.445118

0.020000 0.020000
0.050890

243229435

1.95420
Oo in gas 0.019624

1.935296
23% excess 2445118 _

2.380414

T,.0481605 5.020000 “2 ,9880615

Calories developed by gas

per lb. of coal,

co 1.02882 x 2427
CH, 0.086718 x 11970
Cofg 0.134332 x 11200
Hg 0.069948 x 29030

Sensible heat at

co 1.02882
CH, 0,086718
CoHy 0-134332
2 0+ 245566
Hp 0, 069948
Og 0.019624

0.2512
0.49
0,61
0.245
3.52
0.21975

HM HMw

N2 0.020000 x 0.2512
HAO 0,050800 x 0.5125
Sensible heat

=25-

pane waa

2,496.95
1,038.01
1,504.52
2,030.59
7,070.07

500° ¢, (entering furnace)

00,2582
0,0424
0,0819
+ 0,0601
0,2460
0.0043
0.0050
0.0260_
0.7239 x 485 = G51 1b.-caly


a@ number of discussions have been published on this subject, most of which
assert the desirability of this step, but a few** doubted that the objective
could be accomplished. These objections, however, are based on the possible
application of highly enriched air to present processes, but when we consider
that current methods have been developed around the combustion of fuel by air
@s a fundamental basis, we could hardly expect to obtain the best results
without materially changing these processes. Doubtless, the only reason that
such changes have not been made is on‘account of the inability to produce
oxygen in quantities at sufficiently low cost, to make such application in-
dustrially possible.

AVAILABILITY OF OXYGEN.

In view of the many recent developments in oxygen manufacture, and
considering the increasing cost and decreasing quality of our raw materials,
the Bureau of Mines, Department of the Interior, has taken the metter of the
application of oxygen or oxygenated air to the metallurgical centers for con-
sideration, and has appointed an Advisory Committee to study the problem.

This committee has made a thorough survey of the existing processes
for the manufacture of 99 per cent oxygen. The conclusions reached ty this
survey are that the comparatively small demand for the product has prevented
the installation of large units suitable for metallurgical processes, with
corresponding economies, and by far the greater proportion of the present
cost of oxygen represents the cost of transportation, storage and service.
Large oxygen manufacturing plants can be built to serve metallurgical pur-
poses directly, which, by virtue of their large production and correspondingly
increased efficiency, together with the fact that no compression in cylinders,
storage, transportation, or service will be required, will be capable of
delivering oxygen for the processes at a cost not to exceed $3. per gross
ton. In other words, the Committee finds that the oxygen industry is now able
to make plants for supplying large quantities of oxygen to metallurgical in-
dustries at low cost.

GENERAL APPLICABILITY OF OXYGEN TO METALLURGY «

The Committee has made studies of the possible application of oxygen
to ferrous metallurgy in general, to the metallurgy of zinc, to the manu-
facture of fuel gas, and for some miscellaneous industrial uses, The find-
ings of the Committee on these theoretical studies are of such a revolutionary
character that the members feel the strong advisability of conducting experi-
mental work to verify the truth thereof, as well as to make changes in furnace
design and processes in order to take full advantage of the probable benefits
to_be gained.

* Cottrell, F.G., The Future of Oxygen Enrichment of Air in Metallurgical
Operations; Met. and Chem. Eng, vol. 23, 1920, pp» 53-56.

Johnson, J.E, Jr., The Future of the Iron Blast Furnece: Met. & Chem. Eng.,
Vol, 16, 1917, pp. 17-20. ‘

Edwards, Chas. A., Theoretical Effect of Increasing the Oxygen of the Blast
Supplied to Blast Furnaces: The Iron & Coal Trade Review, Jan.17,1913,pp.92-93,
** Derclaye, M.,Influence de la surchauffe, de la dessication et de le sur-
oxygenation du vent souffle sur le marche des hautsjourneaux: Revue Universelle
des Mines. Tome 15. Liege, Oct. 1, 1922, pp. 99-160

Wright, H.E., The Chemical and Thermal Conditions in Blast-Furnace Practice,
Engineering, May 7, 1920, pp. 641-633,

-4


troubbe. It is not uncommon to have » furnace running normally with a good
grade of product, when suddenly with no apperent reason, the hearth section
begins to chill, the slag becomes black and the furnace is in trouble. The
only relief available for conditions of this kind is more heat in the hearth
and bosh section, which heat cen be secured Only by the combustion of ad-
ditional coke in the hearth section; and it requires from 12 to 15 hours for
coke to reach this zone ufter being charged.

The chilling of the hearth is progressive end may prevent regular
tepping; if so, the time required for the extra coke to reach the seat of the
trouble is increased and in many cases it is almost impossible to prevent a
complete freezing up of the furnace.

fo prevent this condition of affairs the furnece operator of
today is always charging more than the theoretical amount of coke, so that
when an emergency of this nature arises he has a reserve supply of heat to
help counteract the chilling until he can effect relief, This additional amount
of coke may be considered as insurence against trouble, and considered in that
light is a good investment.

Now let us assume that the operator is using a blast which is a mix-
ture of oxygen and air, the amount of oxygen being regulated at will, If in
this case his hearth begins to chill, all he must do is increase the oxygen
content of the blast, and he will immediately increase the high-temperature
heat in the combustion zone. He will be enabled to decrease his coke consump-
tion to the minimum amount required, kmowing that as his requirements change
in the lower and formerly inaccessible part of the furnace, he can, by the
addition of more oxygen, increase the amount of heat in that zone and effect
immediate relief,

The actual amount of coke charged in excess of the minimum requirements
will vary in different plants and under different management, so that no
estimate can be made 4s to its magnitude. However, taken collectively, it
represents millions of tons of coke consumed by the industry each year.

Another factor in the industry to be affected by oxygenated blast will
be that of chemical control of the process. It is known thet the available
hearth heat exerts a great influence on the chemical composition of the product.
This is demonstrated by the fact that furnace irregularities in the nature of
hearth-heat deficiencies are accompanied by "off-grade" iron. A slight in-
crease in humidity will often cause a furnace to produce high-sulphur iron,
With a positive control of this hearth temperature, any irregularity could be
checked before it had progressed far enough to show in the product, and it is
believed that with the use of oxygenated blast a much closer chemical control
will be attained than has been previously considered possible.

At this point it may be well to mention what would probebly be the
effect of oxygenated blast on the absorption of sulphur by iron, Powell*, in
his paper "Forms of sulphur in Coke, and Their Relations to Blast Furnace
Reactions"; states that the major portions of the sulphur in the finished iron
is absorbed from sulphur vapor by the spongy iron; and inasmuch es the pressure
* Powell, Alfred R., "Forms of Sulphur in Coke, and their Relation to Blast-

Furnace Reaction", Trans. A.I.M.E., Feb. 1923.

-16-


General Conclusions regarding Employment of Oxyeen in the Open Hearth,

The foregoing study of the open-hearth process has convinced us of
the following:

1. While the application of oxygen for combustion in the open hearth
will effect some saving in fuel energy, with our present refractories the
saving will be in the form of a by-product and not of practical value. How-
ever, if we can prepare refractories which will withstand much higher tempera-
tures, the application of oxygen to the process will be of great value, both
in saving fuel and increasing materially the speed of the processe

2. That the application of oxygen for combustion with an idea of
substituting cheaper fuel for the very expensive fuel used today is a field
of particular promise.

3. Taken from the standpoint of quality of product, the substitution
of oxygen for air in the last part of the process will enable us to make in the
open hearth steel of electric furnace quality.

4. That the substitution of oxygen for the iron ore now used as an
oxidizing agent will not only give a higher grade product, but it will decrease
the time required for the process by about 3 hours.

APPLICATION OF OXYGEN TO THE MANUFACTURE OF ARTIFICIAL GAS.

While the manufacture of city gas was beyond the scope of this investigs-
tion as originally outlined, there ere certain possibilities in that line which
we will state briefly,

Water-gas made with atmospheric air is largely used for city purposes,
but in order to meet the accepted standards of heating value and illumim tion,
which vary in different cities, it is necessary to "doctor" the gas by the
addition of hydrocarbon oils.

Water-gas made with atmospheric air has a heating value less than 300
B.T.U. per cu.ft., bat gas made in the same manner, substituting oxygen for
air would have a heating value of about 400 B.T,U. per cu-ft. Such gas would
require less additions of oil to bring it up to heating value standards of 500
to 600 B.T.U. now required, and this smaller quantity of added oil would
probably be sufficient to meet the illumination standards,

With a 400 B.T.U..gas available it would be much easier to induce
municipalities to eliminate the obsolete illumination stendards then hes been
found possible heretofore with @traight water ges, particularly es this moderate
heating value gas could be produced at a very attractive figure.

With this in view, we have prepured the following brief comparison

between the process of making water-gus todey and » proposed process using
oxygen and stee¢m in the regular gas producer.

+33


Producer using Gas Coal end Oxygen,

bnalysis of coal Analysis of gas using air and
Per cent s%eum - regular producer practice
c 69.472 co 24.5
Ee 5.€9 CH, 3.6
Ep 2.00 Cay BQ
s 0.94 Cag 3.7
Og =-11..0 Ea 17.8
B20 5.08 03 O4
Ash (less S) 6.66 Ng 46.8

The ash produced contained 4.66% of carbon.

Calorific power per cu.ft. of gus,B.T,U. 221

Gas at O° C, and 760 mm per 1 1d, of coul,cusfte 53.83
Coal required for 1000 cu.ft. of gas, lb. 18.57
Steam per 1000 cu.ft. of gus, 1b. 6.568
Coal equivalent of above steum, lb. 0.821
Totel coal consumed per 1000 cu.ft. of gus, lbe 19.391

Temperature of gus at top of producer °F end °C, 1900 - 1038

The effect of substituting oxygen for the eir now used in producer
ges practice will be that of decreasing the nitrogen passing through the
producer und existing in the resultunt gas, decreasing the heat carried from
the producer by the sensible heat of the nitrogen, and increasing the culorif-
ic value of the gas by eliminating the greater portion of its inert muterisl,

Nitrogen per 1000 cu.ft. of gas, cu.ft, 468
Nitrogen in gas per pound cosl, cu.ft. 25.19
Nitrogen in ges per 1b. of cowl, 1b. 1,965
Nitrogen contained inl lb. coal, 1b. 0.02
Atmospheric nitrogen in gus per 1b. coal, lb. 1,945
Heat as sensible heat imparted to etmospheric

nitrogen per 1b. coal B.T.U. 936.5

Now if we relieve the producer of imparting 936.5 B.t.u. to nitrogen
for each pound of coal gusified, we muy absorb the heat by decomposition of
more steam and the production of more combustible gus.

Heat of decomposition of steam per pound (at 100°C) B.T.U..,.. 5740
Steam decomposed by heat guin of 936.5 B.t.u. to producer is 936.5

divided ty 5740 equals 0.1631 1b, of stewm, If we make this change we will
secure gas per pound of coul as follows:

-34-


being an ideal refractory for even the present requirements. The brick as
used today has a fair life as a refractory, but is in no sense of the word,
a heat insulator nor is the endurance of this material in the service to
which dt is subjected, great enough to allow us to supplement it by a heat
insulator. What the industry needs is a brick so resistant to heat and
metallic fumes, and one of such thermal expunsion, that it will not only
serve as the silica brick does today, - as an uncovered arch and wall - but
will stand the still more severe test of being covered with @ heat-insulating
material to prevent, in a large measure, the too great heat loss through
these sections. 4s to the possibility of obtaining such e material, we see
no reason to say it can rot be done. Price should be of secondary considere-
tion, for such a material once introduced, would not only add materielly to
the life of the furnace, but would save millions of dollars in fuel cost.

In the matter of applying oxygen to metallurgical processes, our
first thought is that of increasing temperatures. As our present refractories
are now subjected to their maximum working temperatures, we will not consider
the matter in that connection at present, but more with the idea of reteining
a@ greater percentage of the totul heat for a useful work then is the present
practice. Clemmts gives the loss of heat by radiation for the regenerators
as 15.50% of the heat lost, and that from the chimney gases as 36.2% of the
heat lost. The chief function of the regenerating system in our present
hearth process is that of increasing the temperature of combustion by adding
sensible heat to the gases before they are burned. With oxygen available we
will have another method of increasing the flame temperature, which, instead
of heating the gases, will simply decrease the amotint of inert gases entering
the furnace, and diluting the calorific intensity of the reaction. Suppose
that we eo even further than the regenerators, and start by replacing with
pure oxygen the air now used in operating the gas producers, increasing at the
same time the steam used in order to dampen the higher producer temperature
otherwise obtained. We will now secure a fuel gas of greater calorific power
which may be burned from one end of the furnace only, using a mixture of
oxygen and air, the oxygen content of which may be regulated as our tempera-
turs requirements dictate. From the exhaust end of the furnace, instead of
passing through regenerators with their accompanying expense and heat loss,
let us carry the reduced volume of gas through a waste-heat boiler, lower its
temperature to 300°C,, and utilize the heat above this temperature in the
generation of steam.

With e process of this nature we will not only eliminate the checker-
work, but will take a big stride in the way of efficient combustion and
proper direction of the flame, In our present furnace, any mixing of air and
fuel gas must be done in a crude manner, in that the only burner possible, in
order to withstand the action of the intensely hot gases and flame during half
of the operation, must be of a highly refractory material, and even this is
always losing efficiency as a gas mixer due to its "slagging" awey. If it

t weverse the flow of gases to the furnace it would be-
come possibla Be truct en efficient burner which would not only effect a
perfect mixty the gases, but which might be used effectively to direct
the flow ar gas in aty, manner desired, It is’ just possible that, with a
device of ‘this kind, we would be able to direct the flame to follow the bath
more closely than is possible today, and relieve the roof to some extent of
its high-temperature condition. With this in view, we havé prepered the
following calculations.
22m



THE USE OF OXYGEN OR OXYGENATED AIR IN
METSLUURGICAL AND SLLIED PROCESSES.

FOREWORD.

For some years this subject has been of interest to metallurgists.
Previous to the War some work was done in Belgium on the enric % of the
blast with oxygen in connection with the smelting of iron or the blast
furnace. In the Mnited States, the late J. E, Johnson, Jr. interested
in the possible use of oxygen for metallurgical operations 4 cerried on
some experimental work along these lines previous to his deavh. Dr. FW. Ge
Cottrell, formerly Director of the Bureau of Mines, Devarty. of the
Interior, and now Director of the Fixed Nitrogen kesea atozy, Depart-
ment of Agriculture, first directed the Bureau's attention to this subject.

When it first began this work, the Director of the Bureau of Mines,
because of his interest in this invest tion, asked Mr. M. H. Roberts,
Vice-President of the Franklin Railway Supply Company to select an Advisory
Cormittee to work with the Bureau on this subject; it also asked Mr. Roberts
to act as Chairman of this Counittee. The personnel of the Committee which
was selected by Mr. Roberts is as follows:

CHATRMAN:

Mr. M. H. Roberts, Vice-President of the Franklin Railway
Supply Company and Consulting Mechanical Engineer,
Bureau of Mines, Department of the Interior, No. 17
East 42nd Street, New York City, New York,

MEMERS:

Dr. F. G. Cottreil, Director, Fixed Nitrogen Research Laboratory,
Department of Agriculture, Washington, D. C.

Prof. W. L. DeSaufre, Chairmen, Mechanicel Fngineering Depert-
ment, University of Nebraska, Lincoln, Nebraska.

Dr. D. A. lyon, Chief Metallurgist, Bureau of Mines, Department
of the Interior, Washington, D. C.

Dr. R. B. Moore, Chief Chemist, Bureau of Mines, Department of
the Interior, Taskington, D. C.

Dr. R. C. Tolman, Professor of Physical Chemistry and Matne~
matical Physics, Californie Institute of Technology,
Pasadena, California.

Mr. J. W, Davis, Mechanical Engineer, Bureau of Mines, Depart-
ment of the Interior, Wasaington, D. C.

Mr. F. W, Davis, Metallurgist, Bareav of Mines Station,
University of Minnesota, Minneapolis, Minn;

Mr. Frenk Hodson, President, Electric Furnace Construction Co.,
908 Chestnut Street, Philadelphia, Pa.

Mr. P. H. Royster, Physicist, Bureau of Mines Station, University
of Minnesota, Minneapolis, Minn.

Dr. H. W, Giliett, Cnief Alloy Chemist, Pureaw of Mines Field
Office, Corneil University, Ithaca, N. Y.

-1-


Heat Distribution - Heerth & Posh.

B.T.U.
Heat to reduce Mn0z to Ma (25.7 x 4100) 105,370
Heat to reduce MnOg to MnO (6.7 x 871) 4,914
Latent heat of fusion of Mn & heat in Metal at
3200° (25.7 x 949) 24,389
Reduction of Si0, (0.39 x 12600) 4,914
Latent heat of fusion of slag(53.3 x(1080-988)) 4,904
Total heat in MnO to 3200°R(6.7 x 1542) 10, 331
Iatent heat of vaporization of Mm (3 x 6.9 x 1791)
33,312
Radiation, conduction ete.(by difference) __30, 514
Total heat utilized in hearth & bosh 219,570
Heat Distribution - Shaft.
B.T.U.
Heat to reduce Fep0z (5.5 x 3142.8) 17,285
Heat to raise carbon to critical temperature
(86 x 1440) 123,840
Heat imparted to slag forming materials:
$id, (17.1 x 0.3209 = 5,487)
§3.203(5.8 x 0.3633) = 2,107)
CaO (24,5 x 0.2995)=_7,338)
14,932 x 3140 46 ,886
Heat to calcine CaCOgz (15.3 x 1847) 28,259

Heat to raise MnO, to 3200°F (58.6x0.4918x3140) 90,493
Heat imparted to fron (including L.H. of fusion)

5.5 x 661 3,636
Radiation, conduction, evuporation of H20 etc. 91,677
402,076

In attempting to predict ty culclations the effect of enriching the
blast in this process we encounter another pecularity of the production of
Menganese: In ordinary practice us shown above, about 16% of the total carbon
charged is oxidized in the hearth and bosh section by the oxides of Mn end Si,
the oxygen for this reaction being originslly combined with the metel, intro-
duces no nitrogen into the smelting zone. Now, us we increase the oxygen con-
centration of the blast, and add more ore to absorb the greater smelting heat,
this increases the percentage of carbon oxidized by oxygen of the ore, so that
the requirement of blest oxygem per pound of coke is naturally reduced. Of
course, the weight of CO produced from a pound of coke will be the seme regard~
less of the source of the oxygen, but with each increwse in oxygen content of
the blast and « corresponding incresse in burden the nitrogen in the products
of combustion will be decreased, first by the elimination of nitrogen from the
blast, and secondly by the decreased quantity of blast required. This double
decrease in nitrogen will have a very marked effect on the heet distribution
for relatively smell increases of blest oxygem.

-41-


Sufficient eperating data could not be procured from any individual
furnace to prepare heat belances, so we have been obliged to take figures
which represent average practice of severul furnaces, These figures are not
as complete as desired, but it is probedie that reuwl complete datu of this
nature do not exist. or example, in practice, the charges are souked with
water to reduce the top temperature, and sometimes water is charged direct.
The furnace operutor is interested only in results, and as he is not charging
for this water against his operation, he has no reason to determine or record
the amount. However, the amount of this water does have a direct bearing on
the heat distribution figures, und should be accounted for, The meterial
balunce of the process is as follows!

Material and Pounds To To
Analysis Charged Metal Sleg
Coke 100
$10. 6.5% 6.5 Si, 0.39 Sid, 5.7
tiob3 3.0% 3,0 41503 3,0
Cad 4.5% 4.5 Cad 4.5
c 86.0% 86.0 Cc, 1,8
Ore 92
S103 8.6 7.9 $10, 7.9
Fe203 «(8.5 7.8 Fe, 5.5
Mn0g 63.7 58.6 Mn, 25.7 MnO 6.7
41203 3,0 2.8 41203 2.8
Limestone 38
Si0, 7.0 2.7 $10, 2.7
CaC0z 93,0 35.3 20 20,0
Air 398.5
Og 23.1 (ary) 91
sips 76.9 w 303
H30 4.5

Before prepeuring « hest balance we must first determine the critical
tempersture. This was done by plotting the hearth and besh requirements«on
Jomson's curve of critical temperatures, and peve a value between 3200 and
3300°F, und for the following calculations 3200° has beer used, being the
most conservative. On this basis the following heat churt hes been prepered,

=39-


500 001
a plast: |
0}
~ ec oy]
iM io co
< oi a
s
N 4
|2O0 on x ke
00g S W a Wa
ES NAB
\
8 iy
N
xX
Hearth Heat required fer M 5 "Ag.
TOT OO a
Vrcantage Oe \in Blast
10. 40 rn 60 70 80 100



Significance of Increased Smelting Heat.

In order to comprehend fully the value of this increased smelting heat
to the industry, one must realize that conditions up to the present are:

1. The efficiency and rate of operation is governed by the smelting
ability of the furnace.

2. The smelting ability is depemdent finally upon the amount of avail-
able high-temperature heat in the hearth and bosh.

3. This high-temperature heat, being generated in the most inaccessible
part of the furnace, is absolutely beyond any direct control.

4. Any material changes in hearth heat can be accomplished only by
charging fuel in the top of the furnace, and will not be effective until the
additional material reaches the hearth, a period of from 10 to 15 hours.

5. No changes in heat application or efficiency in the shaft will be
effective on the operation as a whole inasmuch as they can not change the
smelting rate.

With more oxygen available in the blast, the smelting ability
of the furnace will be increased beyond the speed of the preparing zone in
the shaft, transferring the limiting conditions from the inaccessible hearth
section to the shaft section, where ary change may be accomplished with com
parative ease. This fact will make it profitable to conserve the heat in the
shaft section. Up to the present time this shaft heat has usually been in
excess of requirements, so much so in mary cases as to necessitate the charg-
ing of water in the top in order to dissipate the excess heat and protect the
top of the furnace. With the hearth heat increased by the addition of oxygen,
and the smelting rate accelerated, we will treat more ore in the shaft, which
will absorb the additional heat; and as we reach fairly high concentrations
of oxygen we will actually find a deficiency of shaft heat. Then we can
begin to introduce shaft economies to increase production . For instance, in
present practice, no attempt is made to charge dry ore, the moisture content
ruming from 8 to 15 per cent, also we are making the furnace calcine the lime-
stone, both of which operations could be accomplished outside of the furnace,
and the result would be a saving of about 10 per cent of the shaft heat.
Another item to be considered in this cormection is that when calcining the
limestone in the furnace we are increasing the carbon dioxide content of the
gas, thereby. decreasing its power for reduction of iron. There are doubtless
many other economies which may be effected in the shaft section, all depending
on increasing the smelting capacity of the furnace sufficiently to make them
worth while.

Doubtless the application of oxygen will revolutionize the art of
smelting and it will probably change the whole operation and equipment. How-
ever, in order to demonstrate the value to the industry of a development of
this character, it seems advisable first to adapt the process to present-day
equipment. The first thought was to supply a furnace with blast of 40 per
cent oxygen, but in this practice there would be insufficient reducing gas,

-l-


CONTENTS.

Foreword eoecessseeceee
Introduction........
Possibilities of Applying Oxygenated Air.......eseeee
Availability of Oxy gm... sees eee cece
General Applicability of Oxygem to Metallurgy.
Application of Oxygen to the Smelting of Iron.....
Historical... cesses ee eee ce eees eevee esses
Increasing the Oxygen Content of the Blast
Thermadynamic Principles in Smelting.
Calculations.......... abe n cree eene
Farnace charge and products... wee
Utilization of "smelting hest® in hee rth and bosh....
Hearth heat available... . cc cess eee eee cer creer ones -
Significance of Increased Smelting Heat.
Comparison of overating casts between furnaces using
ordinary eir end enriched air......... .
Utilization of Oxygen to prevent Chilling or Freezing
of hearth zone.......-....- re es seeteereeee
Results to be expected by use of Oxygenated Air....
Bessemer Process for the Manufacture of Steels.ecssssecssecee
Thermal Requirements of Bessemer ProCess..e+sseceesesreces
Application of Oxygen to the Open-Hearth Process for
making Steel....

beet eeee

Cakoulations...... ce eee ee eee eee
Conclusions regurding Thermal ‘Problems of the Open-heerth.
Available Fuel in Open-Hearth Processaceresceeesssceseeces

Consideration of Chemical Problems of the Oper-Heerth....+
fn Ideal Process employing Oxy goes... eee e secre ee eeceeeee
General Conclusions regarding Euployment of Oxygen in the
OpenwHear ther. cc ccse ccc ceceteceetcceeteerererecsseese ene
Application of Oxygen to the Memufacture of Artificiel Gus.....
Application of Oxygen in the Mamfacture of Ferro-Alloys.-...e
Comperison of making Ferro-Menganese with Air and
Oxygenated Airs. cc ce cece eee na ee enae Pere rer ee ere rere

Pege

FOWUOANTAUNP EAE

re


purpose at $3 per ton will compare favorebly in the cost bulances to 27%

ox gen introduced as ore at a cost af from $4 to $6 per ton even when crediting
the latter practice with the iron retained in the bath. 41s0, inasnmch as this
process will decreuse the time requiremmts by about 3 hours, our capacities
will be greatly increased and our fucl and overhead charges reduced accordingly.

In speaking of chemical possibilities connected with the use of oxygen
in the open-hearth furnace, it is well to consider the higher quality steels.
Steel made properly in the electric furnace is recognized as being of superior
grede and purity to open-heerth steel, and commands a much higher price. One
of the main factors which makes the difference in the two products is the almost
total absence of oxides in clectric steel, which is accomplisned by finishing
the steel under very reducing conditions, The current open-heerth process is
incepatle of duplicating these reducing conditions, inasmuch es the products
of combustion are always of an oxidizing nature, and for that reason a highly
reducing slag, such as is necessary in the electric process for the final puri-
fication, cen not be maintained. However, if we have orygen available in the
open hearth we will be enadled to maintain sutficient flume temperature oy
partial combustion of the ges, and in this manner m possible a highly reduc
ing atmosphere in the furnace. Under these conditions a reducing slag may be
made, and the bath cleaned of its oxides, producing e steel which will be equal
in every respect to that made in the electric fumace,

An Ideal Process employing Oxygen.

In order to illustrate better the possibilities outlined above we will
outline briefly a tentetive prodess with the use of oxygen, in which we will
decrease the required time as well es produce steel of electric furnace quality.

1. Charge furnace. n,ysuel manner, using limestone, scrap, and pig
iron in the solid or molten, /according to conditions.

2. Melt down bath and test for carbon,

3. Add sufficient oxygen ges to replace usual ore edditions, through
iron pipes immersed in bath at cach door.

4. Stir bath with rods and secure preliminary test for quick analysis
of carbon, sulphur, and phosphorus.

5. Add more oxygen, if found necessary by tests.

6. Tap slag, at seme time smtting off air supply to furnace; leave
gas on and admit sufficient oxygen through ports to maintain temperature, but
with gas passing through furnace only partly burned.

7. Charge more limestone and some sand to make second slag.
8. Treat slag with coke until it is partly converted to carbide.

9, If any alloys ure to be added, they should be added at this point,
all except silicon or other acid-forming elements.

10, After bath has been alternately agitated by stirring and allowed to
settle, and the metal is considered to be in a very clean condition, tap and
treat steel in usuel manner,

~32-


Inasmuch as the above figures represent actual practice, we may
assume that 4,729,265 1b.:cal’s uufficient to supply the heat for the
process exclusive of heating the blast. With this as a reference figure in
this particular practice, let us consider the case of al per cent phosphorus
iron and oxygen enriched blast:

Lb. calories , OXygen
Chemical Reection developed, required, 1b.
4P+5 02 = 2P205 300 1b. P. 1,767,690 387
$i+02 = Sid 150 lb, Si 950,090 169
aVn+0,) = ziind 480 1b. Mh 794,000 140
20+0p = 2 00 10501d. 2,552,000 1,400
QFe+0p = 2 FeO 9001b. iron 1,056 ,000 1257
Totals 7,119,600 24353
1b.-cal.
Gross heat developed by chemical reactions 7,119,600
Heat required to raise oxygen to reaction temperature
(2353 x 1500 x 0.23845) ___ 841,609
Net heat developed using pure oxygen 6,277,991
Heat necessary for process from normal
practice 41729265
Allowable heat capacity for nitrogen of blast 1,548,726
Heat capacity of 1 1b. nitrogen (1500 x 0.2726) 408.9
Allowable 1b. of nitrogen (1,340,917 1b.-cal — 408.9) 3788

In other words, for the above practice we can use a mixture of 3788
1b. of nitrogen and 2353 1b. of oxygen, or a 38 per cent oxygen blast, and
obtain the same thermal results in the bath as was the case when blowing 4
high phosphorus bath with atmospheric air.

To estimate the value of this process in dollars and cents will be
difficult, for we have no standard tasic practice against which to compare
it. The best comparison we can make is against the open-hearth pratice of
making low carbon steel, This comparison will cause criticism because
Bessemer steel is recognized as inferior in quality to the open-hearth pro-
duct. We will, however, risk still further criticism by making the assertion
that ty the use of oxygen-enriched blast we will be enabled to make Bessemer
steel of almost as good quality as that of our average open-hearth steel,

Bessemer steel is inferior to open-hearth steel mainly by virtue of

@ much larger content of "sonims," If it were possible to allow steel to
stend for a period after the blow in order to allow a large portion of the
sonims to separate, the product would be of a higher quality. This, however,
would require a higher initial temperature of the bath than iw available in
present practice; but with oxygenated blast available, the tempereture of the
bath could be regulated at will. It would then be a relatively simple matter

to give the steel the desired blow, at the necessary temperature and
then allow it to stand for a considerable period to separate a part of the
sonims.

-20-


SERIAL NO. 2502 REPORTS OF INVESTIGATIONS

DEPARTMENT OF THE INTERIOR

HUBERT S. WORK, SECRETARY

BUREAU OF MINES

H. FOSTER BAIN, OIRECTOR

THE USE OF OXYGEN OR OXYGENATED AIR
IN METALLURGICAL AND ALLIED PROCESSES

(Report of the Committee for the Application of Oxygen or Oxygenated Air.)

BY

F. W. DAVIS, METALLURGIST


Heat Distribution - Hearth & Bosh.

B.T.U,
Heat to reduce Mn0z to Mn 51.4 x 4100 210,740
Heat to reduce MnOz to MnO 13.4 x 871 11,672
L.H. of Fusion & heat in Mn to 3200°F 51.4 x 949 48,779
Reduction of Si0p 0.78 x 12600 9,828
latent heat of vaporization of Mn 18.6 x 1791 x 0.63 20,986
Latent heat of fusion of sleg 92.6 x (1080-988) 8,519
Latent heat of MnO & Heat te 3z00°F 13,4 x 1542 20,662
Radiation & conduction (from originul figures) 30,514
360,496
Heat Distribution - Shaft.
B.T.U.
Heat to reduce Feo0g 34,570
Heat to raise © to critical temperature 123,840
Heat in Slug forming materials:
Si0, 26 x 0.3209 = 8,343
Al ges" 8.6 x 0.3633 = 3.124
(a0 44.5 x 0.2995 = 13,328 _
24.795 x 3140 77,856
Heat to calcine CaC0z 30.6 x 1847 56,518
Heat to raise Mn0z to 3200°F (107.4 x 0,9918:%3140) 165,826
Hest imparted to iron (11.0 x 661) 7,271
Radistion etc, (by difference) 24,885 __
Total 490, 766

The temperature of top gus is ussumed at 400°F, in these calculations;
in practice we muy be enubled to reduce this further with a slight decrease in
sheft heat requirement.

Another assumption mede in these studies is that the emount of
mangenese lost both in slag and in the top gas will remain constent. Ad a
matter of fact, owing to the reduced volume and temperature of top gas, this
particuler loss should be decreased. Likewise, the loss of mangenese in slag
should be decreased in that we will have more smelting heat available and by
this means should climinate most of this loss. These factors will, of course,
make the process even more desirable,

While the above method for meeting the deficieng of heat in the shaft
presets 4 possible line along which to work with the development of higher
oxygen blasts, we feel it rether inadvisable to stert the practical upplica-
tion with so meny complications. Our next thought wes, therefore, thet inas-
much as oll of the existing plants ure equipped with hot-blast stoves, it
might be possible to devise a process utilizing both the hot-blast stoves and
additionel oxygen, in this wey the smelting heat will be obteined at less ex-
pense of shaft heut. After several studies ulong this line we have concluded
that it is the most logicsl manner in which to introduce the process, und that
the benefits to be gsined are surprising.

-44-


Heat carried from the furnace as sensible heat in products of combustion.

°
Temperature at exit 1550 C.

Temperature
Lb. gas Specific heat above 15° Cal.
Ce 3.5228 0.19 + 0,00011 (1550) = 0.3605 1535 1395
Op 0.4152 0.2104+ 0,0000187 (1550) «= 0.2394 1525 152
Ng 9.3590 0.2405 + 0.0000214 (1550) = 0.2737 1535 3926
#0 1.0143 0.43 + 0,000185 (1550) = 0,7068 1535 1100
6573
Cal.
Totel heat 11417
Heat in hot products of
combustion 6573
Heat absorbed in work and
lost by rediation in
furnace and ports 4844
Heat to voilers, (temperature of entrance 575°C)
ture
Lb. gas Specific heat 1 Temperate Cal.
Ws 2.5228 0,19 + 0,00011 (575) = 0.2532 560 358
QO. 0.4152 0,2104+ 0,0000187 (575) « 0.2211 560 51
NB 9.3590 0.2405 + 0,0000214 (575) = 0.2528 560 1325
HZ0 1.0143 0,42 + 0,000185 (575) = 0.5264 560 __-298
. 2032
Temperature at exit 220°C
Temperature
Lb. gas Specific heat above 15° Cel,
CO 2.5228 0.19 + 0,00011 (220) «= 0.2142 205 ull
02 0.4152 0.2104 0,0000187 (220) = 0,2b45 205 18
Np 9.3590 0,2405 + 0,0000214 (220) = 0.2452 205 472
#0 1.0143 0.42 + 0,000185 (220) = 0.4607 205 96
697697 __
Heat absorbed and radiated by boilers - 1335

Now, considering the case of cus meade by oxygen in the producer: The
gas enters the furnace at 500°C., and is burned by a 25% 09-75% N, mixture at
26°C., assuming that we may direct this flame away from roof end therefore use
a higher temperature,


APPLICATION OF OXY GEN IN THE MANUFACTURE OF FERRO- ALLOYS.

The field of ferro-alloys is one of particular promise in the ap-
plication of oxygen to combustion, So far, only » few of the ferro-alloys
respond to blast-furnace reduction because of the inability to supply the
high temperature heat required in this type of furnace. Yor this reason,
electric-fumuce processes have been necessary for the industrial production
of all but three of the common alloys, and as is true with all electric-
furnace processes, the cost of production is very high. Ferro-manganese,
ferro-chrome, and low-grade ferro-silicon cen be manufactured in the blast-
furnace, but only with a very high fuel consumption. Inssmuch as ferro-
manganese is one of the most common alloys made in the blast-furnace, we
have made a study of this process as it exists, and further investigations

as to the results to be expected with the application of a blast enriched
with oxygen.

To outward appearences, the blast-furnace process for the manufacture
of ferro-manganese is practically the seme us the blast-furnace smelting of
iron. However, on closer examination we see that there are marked differences.
In the first place, the coke consumption per ton of ferro-manganese is about
three times that of pig iron, while the heat of reduction of manganese is not
very much greater than that of iron, The percentage recovery in the ferro-
manganese process is much less theif thet of iron. Inasmch es oxides ere being
reduced in both processes, charged in the same manner, and heated by the same
meens there mist be some condition within the furnace itself which expleins
the great difference in economy. Considering the smelting of iron fora
moment; we know that the iron charged as an oxide through the top of the
furnace is rapidly reduced to metallic sponge by the ascending gases, so that
before it reaches the zone of high-temperature requirements, it is nearly «11
in the metallic state, end its only requirement in the nature of high-tempera-
ture heat is its latent heat of fusion, end sufficient heat to liqiify the slag
end reduce a small amount of silicon und menganese. Considering ferro-
manganese; we mow that MnOz is reduced only at very high temperatures in the
presence of solid carbon, so it follows that no chemical change is mede in the
Mn0z during its passage down the shaft. Only the small emount of accompany ing
Fep03 will be reduced here, the major portion of the reduction accomplished
in this precess, that of mangenese, being done in the hearth and bosh section
by heat available above the critical temperature. And it necessarily follows
that as we increase the requirements of heat available above the critical
temperature we increuse materially the fuel consumption of the furnace. Now
with reference to the critical tamerature, this value is higher in the
manganese practice than that of the pig-iron furnace, so we have less heat
available ubove this temperature per pound of coke, Another factor which will
be affected by the high critical temperature is that of low-temperature heat,
as we increase our critical temperature we increase the emount of heat evail~
able below that point, or the heat which passes to the shaft, and in studying
actual figures we find this to be exactly what has heppened. The high critical
temperature has increased the amount of low temperature heat, with the result
that the shaft is always too hot, end we are obliged to churge water in the
top of the furnace in order to lower the top temperature to a sefe vulue.

“37=


Qpen-hearth Investigation - Calculations,
(Data from Richard's problem No. 18)

Coel_used (Illinois run-of-mine)

Proximate analysis Ultimate analysis Ash
Per cent
Fixed carbon 50.87 Totel carton 69,72 Carbon 4.66%
Hydrogen 5.60 Carbon 4,664
Volatile matter 37,32 Nitrogen 2,00
Moisture 5.03 Total sulphur 0,94
Ash 6.73 Oxy gen 11.00
Moisture 5.08
Inorganic residue (6,73)
(Less sulphur) 6.66
Net calorific value 7410 1b. cal.
Ges analysis Gerbon per cu.ft. gas at 32°F,
foe) 24.5 0.245 x 0,54 oz.
CHa 3.6 0,036 x 0.54 1
C2Ha 3.2 0,032 x 1.08
3 3.7 0,037 x 0.54 1"
Ho 17.8 _ 0.20628 "02,
0g 0.4 -0,01289 1b.
Ne 46.8 .

Lb. cal. per cu.ft,

Ib. carbon per 1b. of coal

124.6

0.6972

Lb, of C in ash

0.0673 x (0.0466 + 0.9534)
Carbon gasified

9.0033
0.6939

Cu.ft. of gas produced per

1d, of coal

= 0,6939 + 53.83 cu.ft.

Gas per pound of coal - Pound-culories in pas per 1b. of coal (6,707)

Vol. Cu. ft. Tb./cu.ft.
CO 13.19 0,0780
CH, = 3.6 1.94 0.0447
Co, 362 1.72 0.0781
0g 3.7 1,99 0.1234
Ho «(17.8 9.58 0,0056
02 4 0.22 0,0892
Ng 46.8 25119 0.0781
53,83

0,01289

Lbs. gas 4 vy weight
1.02882 29,09
0.086718 2.45
0.134332 3,80
0.245566 6.94
0.053648 1.52
0.019624 0.56
1.967339 55,64
3.536047


ELAST FURNACE MAKING PIG IRON, USING ATMOSPHERIC AIR BLAST & STOVES.

Hearth and Bosh : i
=) :

7 7 7 : : A H Dona : : :
a i bret : : : POA 8 tg 3 : :
. Be i fBe is iB ibeg i¢ ighie iB i ge iss kL,
tt Slow ise igs toms: ig. isgs ig :O~_ih 8s a geo ore
“ Pif,iae ©, ise PAs igee fe cate Beige ids 8 og
ag (RELRE isk ifgaiis ge ig2e 1% isAifs Se i SE ioe Be
AS igs i Men: idie i Boi PR rH ssi g§ teeiBe kB 1 2% 1:89 SE ike
SS IBS EP a BS Sse Pai ee sys is | ; pegieS igs i $e i Be Ba in8
Ag iam igea iss fag ies 88 iggss ek: pa aise eS RS bee pe
O,- from : a : : Hy i : i : : i :
Biast(Dry) 100.5 760 h157 : 15,77 : i : : i} :
Op- total Pog : i : i : : : H i :
rom Blast : : ; : i ; : : : ; :
(hoist) iol. : ; : i : : : : : H :
C- burned by H : : : H : : : : : : H
Oy of dlast 78,6 } {4375 343,875: : i i ; : : : :
C-"in Iron & ‘ : : : : ! i : : : i ; :
lost in : boy 3 ; i : poof : : H : :
Hearth 5.0: : Dot : : : ; : i H :
o- for reduc- ' : : : ; : i : : H : : :
tion of Si og: : H : : F it H : :
C- total to : : : i : : H H : : : : ;
Hearth 84.5 2740 [1132 : : 95,570! : i i : : : : :
C- total : : : booed H : : : : H : :
charged 88.0! io : : : : i
C- burned in : i : : : i H : i
Shaft 3.5! i | i H bob PoP fo 6 186
CO- produced i : i : : : : : : : ' : a 8 i335,
ta eae 185.5 e7ho 732 $135,786 1285.5; ; | PoP Po : oan

No- from : :
Blast 335.4: 780 : 180
E,0 from : :
“Blast ‘U.8: 780 : 360
H,- from

820 in blast 0.5
Og- from H20

ae Blast w3: H :
He0- An i} boob | :
harge 20.6 H : i : : : : :

60,310 amo 752 ;2h5,515 133544 ot 335.4 | 118 59,577: iaW5,503 245, 51345¥5; 61.2

a
26,125 27H i100: 5,450: 05; | 0.5} |G. 12653; 826; 54450 | 5450 mM 1.3

2056.! 20,6 227.5; 4, 686.

0. from Feo0 : : : : : : : H : :

27 2 : : : H : : i : : :

02- for ¢ 3 i H H H ; : : $3281 : 1 15,092

burned in shaft : : : : : : : H :

O5- net for CO : : : : : : :

oO- in Hearth Gas; } : 185.5 : : poe | fo 14375 1309, 312: sé 20h
CO- oxydized by Net Oa! : : : : foot 122.9 /118 124, 502! : : 2661 } 22.
CO- remaining : H : j 122.9: Poo : 9 : : : H : : :

20,- from C040. t : : : : : :

40,- from stone i :

308. teten : od : i to : i faaene i ‘ya! ame fasagas ae : se we 15.2
sven kote : ‘ * : : ' ‘
Total hearth & bosh heat 489,460 386, 749 73,5

Sensible heat in gas
Heat to shaft 386,749 __ 637, ie B.T.U,
Net available heat 102,711 B.T.U. -9- Net shaft heat



Shaft

75% INCREASE IN PRODUCTION

PROPOSED FERROMANGANESE PROCESS - HOT BLAST OF 26.3% Oo (by wt)

Hearth and Bosh

Sep JO auMToA ¥

F009
joeeeene te eed AED
“mba “yFeqs

of ead Tey)
“naa ‘azeUs

0% GyH Wor Quo
oo ‘atbia fuoTa
-snquos jo 7eoq
“nate

sep doy ut yeaq
~"Gj0oh 48 tat sed
seg Ur "n*L'a|

“aL ‘aseug
- Ut peseeTey!

‘sen £q wotqoag
GH Worry sets
~leg YeaH Te4jo}y,

“AD “3X
ye “qt zed yeoq|

do a

ye amnzeraduay,
“Ong

ysog pue y4reeq
0% yeeH Teqo;/

ra
“qt aed uotzy!
-snquoo fo zeox]
“Tag ioweagg
32 “QE ted yeoy|

do e0uer4Uq)

ge eamnyzereduiay,

8g

6,200
377,077

394, 116
411, 860

wn vapor in top 1,544

34. 783

Heat
Heat absorbed in cooling b

vapor
Gross shaft heat

Heat in top gas

gas ;
Heat of vaporization from condensed Mn

Net available heat in shaft

“NG

362,616

689, 163
326,547

ysog puel
UszteeH UT QT

Iten

Net available heat

Total Heat to H&B
Heat to Shaft

Th5S
80.3
95.

A carbon
2

2
C- for reduc-
tion of MnOo

vo Nnd

90

3

CO plus 0;
27 from ore 2

burned by 02
O- remaining

from Blast
C- in metal

for reduc~

tion of MnO,
to Mn

- from H.

* from Feg0

- from fixe
O» oxydized by 0

- from

Oo~- from Blast
rom Fes.

(Dry
Gg- total from

blast (Moist)

- for reduc-
tion of Sido
C- total

charged
CO- produced

in Hearth &

Sosh
No- from

Blast
Hp0= in blast.

Ho- from Hp0
in Blast

18 Blast

0,
od
:

Ce
6
Bay

On:




3000
a —
a rT
[7
[2000 Fresent Pactize
|
Curve | Showing Theoretical Juyere Vempebaturels
YJ Areiable uth the use of |Oxygenated| Blast
Vixtane Cold & Ory
+h
A
y
000

Percent Qe in Bost
fo 20 30 40 50 oO 70 ao 90