IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR THE PUR- POSE OF OBTAINING PRODUCTS FROM ORES
Year: 1853

page_text: LETTERS PATENT to William Henderson, of Bow Common, in the
County of Middlesex, Manufacturing Chemist, for the Invention
of "IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR THE PUR-
POSE OF OBTAINING PRODUCTS FROM ORES."
Sealed the 13th January 1854, and dated the 14th July 1853.
PROVISIONAL SPECIFICATION left by the said William Henderson
at the Office of the Commissioners of Patents, with his Petition,
on the 14th July 1853.
I, WILLIAM HENDERSON, of Bow Common, in the County of Middle-
sex, Manufacturing Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR THE
PURPOSE OF OBTAINING PRODUCTS FROM ORES" to be as follows:—
These improvements consist of a new method of arranging the flues
and arches of what are commonly called close calcining furnaces. The
furnace I prefer is one with two working beds or soles and a drying
bed on the top. I construct two arches with corresponding flues
between these two working soles. The under arch is formed as flat as

page_text: is safe, and is made either of thin brickwork (2½ inches), or thick cast
iron (1 inches). The top arch is 4 inches fire brick, the bricks being
set 2 inches apart to the extent of two or three courses up the centre of
each flue. By these arrangements, with the assistance of dampers, I
am enabled to cause the heat to be concentrated either on the top or
bottom bed at pleasure.
Another improvement consists of using, instead of one large fire at
one end of the furnace, which always heats the furnace irregularly, two,
four, or more. fires in equal numbers at each end; I prefer four fires, 2
at each end.
-
By using this furnace in connection with the manufacture of sulphu-
ric acid from the sulphuret ores, as described in the Specification of my
Patent of 8th January, 1858, I find, that, besides being able to manu-
facture sulphuric acid from copper ores and reguluses, I can alsp
obtain it from zinc blende or sulphuret of zinc, more commonly called
"jack," and also from the sulphuret ores of antimony, arsenic, and
other sulphurets. By having an uniformly diffused heat all over each
hed of the furnace, and having control over the heat by the dampers
and double arches, I reduce the volatilization of the metals to a
minimum, and obtain the sulphurous acid, which is treated, as described
in the Specification of my Patent of the 8th January, in such a
ner
as to separate as oxydes any metals volatilized, and obtain also the
sulphurous acid, in a fit state for manufacturing sulphuric acid, as is.
also described in Patent above named. The calcined oxides are used
for the manufacture of their metals or oxides, in the usual manner.
The volatilized zinc is also obtained as white oxyde of zine, separated
from the sulphurous acid; and condensed. in the dry condensing
cliambers.
i
The volatilized arsenic is also separated in the same manner, and
obtained for use as arsenic and arsenious acids.
The volatilized antimony, lead, &c., in the ore under operation are
also converted into their oxides, and condensed in the saine manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Henderson in the Great Seal Patent
Office, on the 14th January 1854.
'
.
.1°
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
WILLIAM HENDERSON, of Bow Common, in the County of Middlesex,
Manufacturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of July, in the year of
our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Henderson, Her special
licence that T, the said William Henderson, my executors, adminis-
trators, and assigns, or such others as I, the said William Henderson,
my executors, administrators, and assigns, should at any time agree witli,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully miglit.make, use,
exercise, and vend, within. the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention 'for
"IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR "THE PURPOSE OF
OBTAINING PRODUCTS FROM ORES," upon the condition (amongst others) that
I, the said William Henderson, by an instrument. in writing' under my
hand and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed;
and cause the same to be filed in the Great Seal Patent Office within
six calendar inonthis next and immediately after the date of the said
Letters Patent. .
:
NOW KNOW YE, that I, the said William Hendlerson, do hereby
leclare the nature of my said Invention, and in what manner the
same is to be performed to be particularly described and ascertained
in and by the following statement thereof, reference being had to the
Drawings hereunto annexed, that is to say:
My Invention consists, firstly, in a new arrangement of the flucs,
arches, and dampers of what are commonly called close calcining
furnaces:

page_text: Secondly, in a new arrangement of the fires:
Thirdly, in a means of supplying the different beds or floors of the
furnace with air heated to the same temperature as the different floors,
or air at as much lower a temperature as is desired.
Figure 1, represents a ground plan of the furnace.
Figure 2, shews a plan on the level of the first floor representing
the arrangement of flues, fires, and hot air pipes, the whole arrange-
ment being ready for covering in with the fire tiles which form the sole
of the first bed or floor.
Figure 3, represents a longitudinal section of a two bedded furnace
with drying bed on the top; the section being through the centre of
the furnace shews the method of arranging the double arches.
Figure 4, is a transverse section from A, to B.
Figure 5, is an end elevation.
These furnaces may be constructed of two or more beds, but in general 1
I prefer one with two working or calcining beds or soles, and a drying
bed on the top, which is used simply for thoroughly drying the ore
before the calcination begins.
The Drawings represent the lower arch between the two working
soles as made of cast iron about 1 inches thick. This material I prefer 2
when ores requiring a low degree of heat are to be operated upon;. but
when ores, such as those of copper, are to be worked the cast iron arch
ought to be made thicker, say about 2 inches, or else a light arch of
thin brick work. This under arch, as it supports only the flues on the
top, should have as little rise as is consistent with stability, and be built 2
as close over the sole of the first bed as will leave sufficient room to
work the ores. The upper arch with the pigeon holes in the line of
the flues is built of 4 inches fire brick work, as usual.
The air pipes represented in section at c, Figure 4, and Figure 5,
may be made of cast iron, wrought iron, copper, fire clay, or other 3
suitable material; if metal, they are protected from the direct action of
the fire by being laid in the angles of the flues, and covered with small
fire tiles, as represented at d, in Figure 4.
The form of the fire bars will very much depend on the quality of
coals used, but in general the common steam boiler furnace bar, as 3
shown at e, in Figure 3, will answer very well.

page_text: The number of fires is represented in the Drawings as four, two at
each end; but one at each end might be used, though not so advau-
tageously, and by increasing the size of the furnace six or eight or
more fires might be used in equal numbers at cach end; but for ordinary
purposes I prefer four fires. For a furnace of the inside dimensions of
20 fect, by 12 feet, four fires in equal numbers at each end answer very
well, the object being to obtain as nearly as possible a uniform heat
all over each bed.
The hot air pipes all enter the furnace at the same end, and the
sulphurous acids, &c., leave the furnace by the opposite end by one or
more pipes or flues, and pass on to be treated for sulphuric acid, as is
described in the Specification of my Patent dated 8th January 1853.
Figure 5, shews the air pipes where the air enters the pipes at c,
and passing through the pipes by the draught of the furnace gets heated
to the same degree as the furnace, which it enters at f, in Figure 3,
thence it passes over the surface of the heated orc, and escapes by
9, 9, 9, 9, in Figure 5.
The furnace is worked as follows:-The fires having been lighted
and the furnace brought to the requisite degree of heat (which varies
according to the ores to be operated upon), a charge (of about three tons
for a furnace of the inside dimensions of 20 fect by 12 feet) is evenly
spread on the drying plates on the top, and repeatedly turned over with
the shovel till thoroughly dried; it is then passed through the pipes h,
(the covers being previously removed,) into the second floor or sole,
where it is worked and stirred about in the usual manner through the
two doors at each side shewn by the dotted lines at L, in Figure 2.
When about two fifths of the sulphur, arsenic, &c., have been expelled,
the covers are removed from the pipes i, and the ore is passed into the
lower bed, where the calcination is completed; when this has been done
the covers are removed from the pipes J, and the ore is passed into
the cross arches or "cubs" K. Whenever a charge is removed
from the bottom bed a charge is shifted from the upper bed into the
lower, and a charge from the drying plates or tiles passed into the
second bed; and when the doors and the covers of the pipes com-
municating from one bed to the other, and into the "cubs," or from

page_text: .
the drying tiles, have all been closed, and the calcination begun, a fresh
charge is carried. to the drying tiles, and so on continuously. After
the furnace is fairly started, the time for removing the charges from the
one bed to the other is determined by the state of the ore in the lower
bed, for when it has reached the required degree of oxidation it is at
once removed, and the higher charges follow in their order downwards.
Sometimes the orc in the lower bed will get too hot, and stick to the
tiles, (indeed this has been the chief difficulty in working these close
calcining furnaces.) whilst the upper surface of the ore is comparatively
cold. To remedy this defect I proceed as follows:-When the ore shews.
any inequality of heat between the under and upper surfaces I open
the small door M, and remove with a hook the fire tiles N, over each
fire, as represented in Figure 3; and by pushing in the dampers O, and
P, more or less, and opening the dampers Q; more or less, I canse the
heat from the fires to pass only partially, or, if required, shut it out
entirely from passing under the first bed, and cause it to pass by the
return flues of the fires at the opposite end over the iron arch.
If it is desirable to concentrate the heat on the second bed, this can
also be lone by shutting the dampers O, quite close, and opening the
lampers Q, and P; the heat from No. 1. fire passing under the floor
of the second bed (which it reaches by the slanting flues, as shewn in
Fig. 5,) by the return flues of fire No. 3; and in like manner No. 2.
fire returns by No. 4. fire; and No. 8: firc, by the return flues of No. 1.
fire; and No. 4. fire, by those of No. 2.
If the heat in the whole furnace is too high it can be reduced in-
stantly by opening the four fire doors and shutting off the hot air cocks
R, Figure 3, and opening the cocks or plugs that admit cold air, as
shewn in Figure 3, at S.
In general constant working, however, the furnace should be worked
with all the sets of dampers O, and P, quite open, and the fire tile N,
with the door M, and the dampers Q, all shut, which arrangement
need only be altered under the circumstances above alluded to.
By using this furnace in connection with the manufacture of sul-
phuric acid from sulphuret ores, as described in the Specification of my
Patent dated January 8, 1858, I find that besides being able to

page_text: manufacture sulphuric acid from copper ores and reguluses, I can also
obtain it from zinc blende, or sulphuret of zinc, more commonly called
"jack," and also from tin, lead, antimony, arsenic, and other sulphuret
bres, or from ores containing a mixture of different sulphurets in the
same ore, or from reguluses of those metals separated or combined.
By having complete control over the degree of heat applied, and having
also a uniformly diffused heat over every part of each bed, I'am
enabled to reduce the volatilization of any metals existing in the orc
which have this property to a minimum, and obtain the sulphurous
acid as pure as prácticable, which is treated as described in the Speci-
fication of my Patent dated 8th January 1858, in such a manner, as
to separate as oxides any metals volatilized, and obtain also the sul-
phurous acid in a fit state for manufacturing sulphuric acid, as is also
described in the Specification of my Patent above, named.
The calcined oxides are treated for the manufacture of their metals
or oxides in the usual manner.
The volatilized zinc, arsenic, antimony, lead, &c., are condensed and
separated from the sulphurous acid in the dry condensing chambers or
lues, as described in the Specification of my Patent above named.
By combining two or more of these furnaces together, and allowing
the gases from all the furnaces to mix together in one flue before
passing through the nitre oven, and by charging them alternately with
ore, and keeping the flues very hot, the volatilization is reduced to a
certain extent, and the kilns can be partially dispensed with; yet, unless
greater care is bestowed on the arrangements and workings than is
usually the case with workmen, the continuous production of sulphuric
acid in the chambers is liable to frequent and serious derangement.
And, therefore, although I claim the means of producing sulphuric
acid, yet I consider that the method described in my former Specifica-
tion already mentioned is in all cases to be preferred.
And having now described the nature of my Invention, and in what
manner the same is to be performed, I declare that I claim,―
First, the construction of calcining furnaces with the arrangement of
double arches and corresponding flues and dampers, and the method of
heating by equal numbers of fires at each end of the furnace (such

page_text: number being more than one), by which combination a regular, uniform,
and manageable heat is applied:
Second, I claim the use of such furnaces for the manufacture of sul-
phuric acid from copper, tin, zinc,' and other sulphurous ores and
reguluses, and for the purposes of calcination generally:
Third, I claim the means represented and described of obtaining a
supply of air heated to the same degree or less than the ores in the
furnace: And,
Fourth, I claim the method of manufacturing sulphuric acid by
combining two or more of these furnaces, and working them for that
purpose, in the manner herein described.
In witness whereof, I, the said William Henderson, have here-
unto set my hand and seal, this Fourteenth day of January,
One thousand eight hundred and fifty-four.
WHENDERSON. (L.S.)