Improvements in the Method of and Apparatus for Reducing Ores or Compounds of Zinc, Iron, Phosphorus, Sodium, and other Substances.
Year: 1888

page_text: Improvements in the Method of and Apparatus for Reducing Ores
or Compounds of Zinc, Iron, Phosphorus, Sodium, and other
Substances. .
I, GUSTAF M. WESTMAN, Mining Engineer, of 31 Broad Street, New York, U.S.A.,
do hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
The object of this invention is to provide a new and improved furnace for the
reduction of iron and zinc ores, and the manufacture of phosphorus, sodium and
other substances.
The invention consists in certain parts and details and combinations of the same, as
will be fully described hereinafter and then pointed out in the claims.
Reference is to be had to the accompanying drawings forming part of this
specification, in which similar letters of reference indicate corresponding parts in all
the figures.
.
same on the line x-x of
Figure 1 is a plan of the furnace with parts in section.
Figure 2 is a sectional. side elevation of the
Figure 1.
Figure 3 is a similar view of the same on the line y-y of Figure 1.
Figures 4, 5 and 6 are sectional views of valves for connecting various pipes, as
hereinafter more fully described.
The reducing furnace A of any approved construction is provided at its upper end
with an aperture B leading to a pipe C. extending downward on the outside of the
furnace A and branching into the pipes D and E, each being provided with a valve D¹
or E', respectively. The pipes D and E lead into the bottom of the condensing
furnaces F. and G respectively, which are alike in construction, each being filled with
a suitable filling material, such as coke, etc.
From a lower part of the reducing furnace A lead the pipes I and I¹ connecting
the furnace A with the bottom of the condensing furnaces F. and G respectively, each
of the pipes I and I¹ being provided with a valve I for disconnecting the reducing
furnace A from either of the respective condensing furnaces For G. From the tops

page_text: ་
of the condensing furnaces F and G lead the pipes J and J¹ respectively to a valve K
illustrated in Figure 6, and arranged in such a manner that the two pipes J and J'
discharge into either of the two pipes L or L' as is plainly seen by referring to the
said Figure 6. The pipe L' is connected by the branch pipes L2 and L³ with the
coolers N and N¹ respectively.
The coolers N and N¹ may be of any approved construction, preferably, however,
provided with a cooling chamber, through which atmospheric air or water passes, as
shown in Figure 2; the gases passing through the coolers N and N¹ pass through the
pipes surrounded by the cool atmospheric air or water. Each of the coolers N and N¹
discharges into a receptacle N2 connected by a pipe N³, with a blasting engine o of
any approved construction.
The blast engine discharges into a pipe O' connected with a valve P shown in
detail in Figure 4, and provided with the pipes P1 and P2 leading to the bottom of the
regenerator R and R₁ respectively. The valve P is also connected with a pipe P³
leading to the chimney Q. The pipes O¹, P', P2 and P3 are so arranged that the gases
from the blast engine O can pass either to the regenerator R by means of the pipe P
or to the regenerator R¹ by means of the pipe P2, and while one of the regenerators
is connected with the pipe O¹ the other regenerator is connected by its respective pipe
with the pipe P³ leading to the chimney Q, as is plainly understood by reference to
Figure 4, to carry off the products of combustion. Each of the regenerators R and R¹
is provided with a channel R² connected with the top of the interior of the regenerator
and leading into the bottom of the reducing furnace A. The valve S located in the
said channel R2 serves to connect the respective regenerator with or disconnect it
from the reducing furnace A.
The pipes L and L' are surrounded by a jacket T having an opening in its rim or
in one of its heads leading to the outside. A pipe U holds from the jacket T down-
ward and connects with a valve V located near the valve P and provided with pipes U1
and U2 leading to the regenerator R, and also provided with pipes U3 and U leading
to the regenerator R¹. A pipe U extends from the valve to the pipe L so as to
draw off any surplus gases not discharged to the coolers N and N¹. The valve V is
so arranged that the air passing from the jacket T and the surplus gases from the
pipe L can be discharged into either of the regenerators R or R¹ to be burned.
As shown in Figure 5 the air from the pipe U passes into the pipe U² leading to
the channel R2 of the regenerator R, and the surplus gases entering through the
pipe U³ pass to the same channel R2 of the regenerator R by means of the pipe U¹.
If the valve is reversed the air entering the pipe U can pass through the pipe U³ into
the channel R2 of the regenerator R', and the gas entering through the pipe U can
pass by the pipe U into the channel R2 of the regenerator R¹.
The reducing furnace and the condensing furnaces are all so arranged that
they can be charged as well as drawn, without air being admitted into the
furnaces.
The operation is as follows:
When the furnace is to be used for reducing zinc ores, the reducing furnace A is
charged with zinc ores mixed with coals, and the condensing furnaces F and G are
preferably filled with coke.
the
Now when one regenerator R or R¹ is connected with the reducing furnace A,
other regenerator is shut off from the said reducing furnace by the valve S. The
reducing furnace A is then supplied with carbonic oxide gas heated in the regenerator R
or R and the gases now arising in the reducing furnace can either be taken off at
the top through the opening B or through the pipes I or 1' near the lower end of
said reducing furnace A. When the opening B is connected with the condensing
furnace G, the valve D' in the pipe D is closed, while the valve El in the pipe E is
opened, thus establishing a connection from the opening B through the pipe C and the
pipe E with the condensing furnace G. The valve 12 in the pipe I connecting the
reducing furnace A with the condensing furnace F is then open, so that the highly
heated gases in the lower part of the reducing furnace A pass through the pipe I into
the condensing furnace F, while the gases of a lower temperature in the upper part

page_text: of the reducing furnace A pass through the opening B into the condensing furnace G ;
therefore the condensing furnace F is in operation to condense the zinc vapors while
the other furnace G is cooled off by the waste gases coming from the upper part of
the reducing furnace A.
The arrangement just described can be reversed by closing the valve E¹ in the
pipe E and opening the valve D' in the pipe D, and by closing the valve I2 in the
pipe leading from the reducing furnace A into the condensing furnace F and
opening the valve 12 in the channel 1' leading from the reducing furnace A into
the condensing furnace G. In this case the zine vapors are condensed in the
condensing furnace G, while the condensing furnace F is cooled off by the gases
of a lower temperature coming from the upper part of the reducing furnace A.
The gases after passing through the respective condensing furnace F or G, pass
into the pipes J and J, and, by means of the valve K, are directed into the pipes L
and L leading from said valve K. The air passing through the jacket T surrounding
said pipes L and L' partly cools the gases passing through the pipes L and L'.
The gases from the pipe L' pass into the coolers N and N', are there reduced to a
still lower temperature, and then pass into the receptacle N2 in which they are purified
from dust which settles in the bottom of the receptacle. The gases are then drawn
into the circulating blast engine O which discharges through the pipe 0¹ into the
valve P, from which the gases are led through the respective regenerators R or R¹into
the reducing furnace A, being then highly heated carbonic oxide.
The other regenerator, which is not connected with the reducing furnace A, is
used for burning the surplus gases which pass from the pipe L through the valve V
into that regenerator, a sufficient quantity of air entering at the same time through
the pipe U and the valve V into the same regenerator. It will be seen that either
of the regenerators R and R₁ can be used for supplying heated carbonic oxide to
the reducing furnace A while, at the same time, the other regenerator is employed to
burn the surplus gases.
It will thus be seen that a continuous stream of carbonic oxide gases passes through
the reducing furnace, one of the condensors, the coolers, the blasting engine and
one of the regenerators and the said gases are used over and over again for supplying
the necessary heat for reduction and evaporation, at the same time the surplus
carbonic oxide gases, or so much as is constantly being formed in the reducing
furnace from the coals and the oxygen of the zinc ore, pass continuously from the
lower part of the reducing furnace into the other condensor, carrying the zinc vapors
away to be there condensed, and from there they pass on to the other regenerator
to be burnt.
In defining my invention with greater clearness I would state that in the reduction
of zinc ores it is not only necessary that the gases should convey heat enough for
the operation but also that they should be absolutely free from oxidizing matters.
Ordinary producer gases, made by introducing air into coals can not be free from
carbonic acid. In my process I therefore avoid the admixture of air or oxygen
with the gas. The reduction of oxide of zinc cannot be effected by means of carbonic
oxide alone, a fact that is demonstrated practically by the oxidation of zinc when
heated in contact with carbonic acid, and theoretically by the greater amount of heat
developed by the combustion of zinc than by the combustion of carbonic oxide for
equal quantities of oxygen. The solid carbon mixed with the zinc ore acts as the.
reducing agent and combines with the oxygen of the zinc ore.
And as no air is introduced in the furnace and therefore no chemical change of
the gases can take place, the only object of the carbonic oxide gas is to act as a
carrier from outside of the heat necessary to the reducing operation; this is an
essential point in my process.
In the reduction of zinc ores it has by this system been possible to make a
considerable saving in time, labor and fuel.
The condensation of the zine vapors in mixture with permanent gases depends
exclusively upon the tension of the zinc vapors. In this process one must entirely
regulate the gas outlets so that the zinc that follows the gases escaping at the top of

page_text: escaping lower down, who will then go off with the zinc gases in maximum of
tension.
At an earlier date, when my invention was less perfected than now, all the permanent
gases were carried along with the zine vapors, which arrangement was far inferior to
the one now described in this specification. In the first place the zine vapors would
then not be in maximum of tension. Further only so much of the sensible heat of
the permanent gases could be utilized as corresponds to the difference between the
temperature of the gases when entering the reducing furnace and the temperature
at which zinc is gasified, whereas now a considerable part of the heat carried along
with the permanent gases can be used for preheating the charge in the upper part of
the reducing furnace after the temperature of these gases has gone down below the
gasifying point of zinc. This will evidently save a great deal of heat.
In order to produce phosphorus, 1 use the furnace in a similar manner as above
described in reference to the treatment of zinc ores. Metaphosphate is mixed with
charcoal, silicic acid and asphaltum in the form of briquettes and the latter are
subjected to a white heat in the reducing furnace A with the exclusion of oxidizing
substances so that phosphorus is distilled according to the following formula:
2 Ca (PO3)2 + 2 Si O₂ + 10 C = 2 Ca Si O₂ + 4P + 10 CO.
Instead of using metaphosphate of lime, I may employ orthophosphate of lime.
Sodium is produced as follows:
Carbonate of soda is well dried at a high temperature, and then mixed with well
dried and pulverized charcoal and chalk ground to a very fine powder, the success of
the operation depending in a great degree on the fineness of the mixture. This is
formed into bricks with an addition of asphaltum. The chalk is added for the purpose
of making the mixture less fluid and more porous.
The bricks are subjected to a preliminary calcination, which is continued until all
moisture and carbonic acid cease coming off. The bricks are then further treated
in the reducing furnace as above described in reference to zinc.
When the furnace is to be used for reducing iron ores, the reducing furnace A
is charged with the ore to be reduced in the usual manner. The furnaces F and G.
are filled with coals and now become coke furnaces.
When the blast engine is set in motion, it draws the carburetted gases from
the coke furnaces For G through the pipe L', the coolers N and N1, and the
pipe N3 and forces them into the valve P, from where the gases pass to the respective
regenerator R or. R', are very highly heated, and rise to the top, from where they pass
through the channel R2, into the bottom part of the reducing furnace A. The
carburetted and heated gases now pass through the ore in the reducing furnace A,
reducing it to iron sponge.
The gases arising in the reducing furnace can either be taken off at the top
through the opening B or through the pipe I or I¹ near the lower end of said
reducing furnace A.
When the opening B is connected with the coke furnace G, the valve D' in the
pipe D is closed, while the valve E¹ in the pipe E is opened thus establishing a
connection from the opening B through the pipe C and the pipe E with the coke
furnace G. The valve 12 in the pipe I connecting the reducing furnace A with the
coke furnace F is open, so that so much of the gases as correspond to the new made
gases, pass through the pipe I into the coke furnace F, while the circulating gases
pass through the opening B into the coke furnace G.
The arrangement just described can be reversed by closing the valve E¹ in the
pipe E and opening the valve D' in the pipe D and by closing the valve 12 in the
pipe I and opening the valve I' in the pipe I¹.
In that coke furnace, which is connected with the reducing furnace A through
the lower outlet I introduce a small quantity of air thus producing ordinary
producer gas, which together with the surplus gases from the reducing furnace
goes through the valve K, the pipe L and the valve V to heat one of the regenerators.

page_text: By the inlet of air the coals are transformed into glowing coke which, when the
valves 12, D and E¹ have been reversed, serves for carburetting the circulating
gases, then coming from the reducing furnace through the pipe C. When the
coke is hereby cooled to such degree that the gases do no more get carburetted, and
the coke in the other coke furnace in the mean time has been heated by the inlet of
air, the valves are again reversed and the latter coke furnace is then used for the
carburetting. In this manner no interruption takes place. The carburetted gases
are drawn from the top of the coke furnaces by the action of the blast engine O
and pass through the pipe L', the coolers etc., as above described.
Other ores such as manganese are treated in a similar manner to that above
described in reference to iron ores but in mixture with coke.
Instead of the herein described shaft furnace for reducing lump ore, I use for
reducing pulverized ore an open heart furnace with one or more compartments
in which the ore is spread over the bottom of the furnace where the gases pass over
the ore.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. In a furnace, the combination with a reducing furnace of regenerators connected
alternately with the said reducing furnace, condensors or carburetting furnaces, each
connected by two or more pipes with the said reducing furnace, and a blast engine
connected with the said condensors or carburetting furnaces and the said regenerators,
substantially as shown and described.
2. In a furnace, the combination with a reducing furnace, of regenerators connected
alternately with the said reducing furnace, condensors or carburetting furnaces, each
connected by two or more pipes with the said reducing furnace, coolers connected
with the said condensors or carburetting furnaces, and a blast engine connected with
the said coolers and the said regenerators, substantially as shown and described.
3. The herein described process of reducing zine ores. consisting in subjecting
the zinc ores in mixture with coals to the action of highly heated carbonic oxide,
introducing the zinc gases together with so much of the permanent gases, as corre-
sponds to the quantity of such gases being produced during the process, alternately
in one of two or more shaft furnaces, filled with coke for condensing the zinc gases;
and subsequently reheating the balance of the permanent gases and returning them
through the charge, substantially as shown and described.
4. The herein described process of reducing iron ores to iron sponge, consisting
in passing highly heated carbonic oxide gases through a charge of iron ore, thereafter
separating a part of the gases for heating regenerators and forcing the balance of
the gases through glowing coke so as to again change them into carbonic oxide,
and subsequently superheating these gases and making them again circulate through.
the charge of ore, substantially as shown and, described.
5. The herein described process of manufacturing sodium in a shaft furnace,
consisting in introducing the necessary heat through highly heated carbonic oxide
gas to a charge of briquettes, made from carbonate of Sodium and coal powder.
6. The herein described process of manufacturing Phosphorus in a shaft furnace
consisting in introducing the necessary heat through highly heated carbonic oxide
gas to a charge of briquettes made from phosphates, silica and coal powder.
Dated this 28th day of November 1888.
CARPMAEL & Co.,
Agents.