IMPROVEMENTS IN OXIDIZING MINERALS, ORES, AND METALS; IN REDUCING OXIDE OF METALS; IN SEPARATING CERTAIN METALS FROM EACH OTHER; IN KILNS, FURNACES, OR OTHER APPARATUS FOR THESE PURPOSES; AND IN THE TREATMENT OF THE PRODUCTS OBTAINED THEREFROM
Year: 1867

page_text: LETTERS PATENT to William Henderson, of the City of Glasgow,
Chemist, for the Invention of "IMPROVEMENTS IN OXIDIZING MINERALS,
ORES, AND METALS; IN REDUCING OXIDE OF METALS; IN SEPARATING CERTAIN
METALS FROM EACH OTHER; IN KILNS, FURNACES, OR OTHER APPARATUS FOR
THESE PURPOSES; AND IN THE TREATMENT OF THE PRODUCTS OBTAINED
THEREFROM."
Sealed the 4th October 1867, and dated the 6th April 1867.
PROVISIONAL SPECIFICATION left by the said William Henderson at the
Office of the Commissioners of Patents, with his Petition, on the
6th April 1867.
I, WILLIAM HENDERSON, of the City of Glasgow, Chemist, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN, OXIDIZING
MINERALS, ORES, AND METALS; IN REDUCING OXIDES OF METALS; IN SEPARATING
CERTAIN METALS FROM EACH OTHER; IN KILNS, FURNACES, OR OTHER APPARATUS FOR
THESE PURPOSES; AND IN THE TREATMENT OF THE PRODUCTS OBTAINED THEREPROM,"
to be as follows:-
These improvements have for their object-1st, the more rapid oxidation
of ores and minerals when they contain less: the 12 per cent. of sulphur, or of
metals when in a state of fine division, so as to effect this in a very short space

page_text: of time and with as little manual labor as may be; 2ndly, the reduction of
oxides or carbonates of metals to the metallic state in a very short space of
time, and by a continuous process completely under command, so as to
accomplish it effectually; 3rdly, the separation of arsenic, antimony, tin,
bismuth, and several other metals from copper and other ores, reguluses or
matts; 4thly, the further treatment of these products so as to obtain metals
and other substances therefrom; 5thly, the improvement of kilns, furnaces,
and apparatus for these purposes and objects.
The improvements are as follows:-
1st, an upright rectangular chamber of from 12 to 20 feet in height built
of thin fire-brick work having a heating space in three sides of it, and outside
a strong supporting wall. The heating space may be filled with fire-bricks
crossing each other at as large intervals as practicable, so as to leave free
passage for the heating flame. The lower part of two of these spaces is arched
over with brickwork to make room for two fire-places, and the arch is pigeon-
holed to allow of the free passage of the flame upward through the heating
spaces or loose brickwork as the case may be. The interior of the upright
rectangular chamber is fitted with shelves at short intervals, placed at such
angles as will retain a certain portion of the mineral to be operated upon
without allowing it to slip off until it has been overloaded. The next shelf is
placed upon the opposite side of the chamber so as to receive on its upper
surface, next the wall, what has been delivered from the one above it on the
opposite side of the chamber, and the shelves are thus continued to nearly the
bottom of the chamber which terminates in a hopper with a slide in the bottom.
The ore is delivered by proper machinery regularly through a slit in the arch
(which encloses the chamber at the top) on to the top of the first shelf. This
machinery should be capable of the nicest adjustment as to delivery.
When ores, or minerals, or reguluses containing not more than 12 per cent.
of sulphur are to be calcined, either alone or mixed with common salt, or other
chlorides, I proceed as follows:-The two fires are lighted, or gas and hot air
are introduced into the heating spaces and the heat gradually raised, so that
the interior of the chamber is brought to a red heat. The ore reduced to a
coarse powder, which must be quite dry, is then slowly fed on to the upper
shelf, whence, when it has been sufficiently loaded, it slips on to the second
shelf, and so on through all the shelves till it has reached the bottom. In each
fall it passes through the ascending current of air and other gases, and is by
this means rapidly oxidized. If it be found on reaching the bottom of the
chamber to be insufficiently oxidized the feed at the top must be reduced in
proportion; if too much oxidized the feed must be increased. The sulphurous

page_text: or other gases are drawn off at the top of the chamber by a separate flue, and
can be condensed.
To separate the arsenic, antimony, tin, bismuth, or other metal from copper
ore, reguluses, or matts, I reduce the ore, reguluses, or matt by calcination so
that it does not contain more than 10 per cent. of sulphur; I then reduce it
to a fine powder and mix with it 3 cwt. of common salt to the ton of ore, or
regulus, or a proportion equivalent to this of chloride of iron, manganese,
calcium, or other earth, or easily oxidizable metal. The mixture is then passed
through the chamber at such a speed as will be found just sufficient to oxidize
the whole of the sulphur. The tin, arsenic, antimony, and other volatile
metals will have been entirely converted into chlorides, which volatilize and
are condensed in flues or condensers with some small portion of the copper.
The resulting ore is washed with hot water, to separate any soluble chlorides
of copper, and the residue which contains the great bulk of the copper perfectly
free from arsenic, antimony, tin and bismuth is smelted in the usual or any
other manner; the small quantity of copper in solution is precipitated with
iron in the usual manner. Chlorine or perchloride of iron in a volatilized state
may be mixed with the air admitted to the calcining chamber, and will much
facilitate the oxidation. Metals in a fine state of division are oxidized in the
same way as ores containing sulphur.
2ndly, when oxides or carbonates, or mixtures of oxides and carbonates
of metal are to be reduced, I use a similar apparatus, taking care, however,
that the hopper at the bottom is carefully luted and made tight so as to
prevent the entrance of air. The cold chamber is then filled with carbonic
oxide, coal gas, hydrogen or other gas, or mixture of gases, having a strong
reducing tendency, which are admitted near the bottom of the chamber. The
gas should maintain a slight pressure inside the chamber, so that when a
stopper is taken off it will blow slightly outward and not permit the entrance
of air. The gas ascends through and fills the whole of the inside of the
chamber, and is taken down again to the bottom of the pile through two small
chimneys formed in the solid outside wall. Until it is quite certain that all
air has been expelled from the chamber the gas is allowed to pass on to the
chimney; when this has been assured the damper or valve leading to the
chimney by these exits is then closed, and those connecting the beating spaces
with the chimney are then opened; heated air is at the same time introduced
at the bottom of the heating spaces, and the mixture lighted; the whole will
then gradually heat up to any required degree of intensity.
To reduce oxides of iron I prefer the chamber to be heated to a bright red
heat. The oxide of iron reduced to a very fine powder is then supplied in a

page_text: regular stream on to the shelves or retarders, and when it reaches the bottom
will be found to be either wrought iron or steel in very fine flakes. The
termination of the iron hopper at the base of the reducing chamber should be
continued long and narrow, so that the iron or steel powder may be perfectly
cold before being allowed to escape into any waggon or barrow. Artificial
cooling may be adopted with advantage by placing a jacket of wrought or cast
iron round a portion of the hopper, and causing a constant circulation of water
or air to pass round it. The metallic iròn thus produced from pure oxides of
iron may be used in this state for precipitating copper and other metals from
their solutions, or may be pressed into blocks and welded into superior wrought
iron, or melted into cast steel. A further carburatation of the reduced iron
may be effected by a slower feed or by using gases richer in hydrocarbons,
alloys of iron and manganese, or iron and titanium or chromium, or other
metals may be effected by reducing their mixed oxides after this manner,
afterwards melting the reduced compounds in crucibles or gas furnaces.
'Oxides or carbonates of copper, zinc, lead, and other metals may be reduced
in the same manner by regulating the heat and speed of delivery.
and
The construction of the reduction chamber may be varied. Instead of
shelves, bars of a rectangular shape may be used with the upper surface con-
siderably curved so that nothing will lie permanently upon them. These bars
should be built into the chamber so that every second row comes exactly under
each other, and the intermediate row fills the spaces between, à considerable
distance in height being left between each row so as to allow a clear space for
the ascending gases all round. Or the bars being of sufficient diameter may
be oval, or even round, with a larger diameter still.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Henderson in the Great Seal Patent Office on the
5th October 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENDERSON, of the City of Glasgow, Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of April, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
William Henderson, Her special licence that I, the said William Heuderson,
my executors, administrators, and assigns, or such others 'as I, the said

page_text: William Henderson, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might 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
OXIDIZING MINERALS, ORES, AND METALS; IN REDUCING OXIDES OF METALS; IN
SEPARATING CERTAIN METALS FROM EACH OTHER; IN KILNS, FURNACES, OR OTHER
APPARATUS FOR THESE PURPOSES; AND IN THE TREATMENT OF THE PRODUCTS OBTAINED
THEREFROM," upon the condition (amongst others) that I, the said William
Henderson, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, 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 months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that 1, the said William Henderson, do hereby
declare the nature of my said Invention, and in what manuer 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 :-
These improvements have for their object, 1st, the more rapid oxidation of
ores and minerals when they contain too little sulphur to burn of themselves
when exposed to the air in a chamber previously heated, or of metals when
reduced to a state of fine powder; 2ndly, the reduction to the state of metal
without melting of oxides and carbonates of metals; 3rdly, the separation of
arsenic, tin, antimony, bismuth, and several other metals from copper ores,
reguluses, or matts; 4thly, the further treatment of the above products so as
to obtain metals and alloys of those metals therefrom; 5thly, the improve-
meut of kilns, furnaces, and other apparatus for these purposes and objects.
My improvements will be fully understood by the following description and
the accompanying Drawings.
Figures 1, 2, 3, and 4, represent an oxidizing furnace with large shelves,
and heated by means of gas and beated air; Figures 1 and 4 represent a
section and a plan of a double furnace or pair of furuaces arranged side by
side; Figure 2 is a cross section; and Figure 3 an elevation.
The furnace is first heated by a coal or coke fire kindled on the floor of the
furnace through the door a, which is raised for the purpose.
When the
furnace has reached a dull red
attached to the furnace at b, b.
heat the gas is introduced by pipes which are
The air enters the furnace at the top at c, c

page_text: Figure 4, and descends through the narrow flue passing under the furnace, as
shewn by the dotted lines in Figure 4, where it divides to supply air to both
sides of the furnace. The heated air ascends through three holes in each of
the small side flues and mixes with the gas, and takes fire if the furnace has
been previously brought to a sufficient heat. By shifting the fire-clay blocks d
more or less the supply of air is regulated. The supply of gas is regulated by
a valve in the pipe. The products of combustion pass into the flues e, e, e,
Figures 1 and 4, and pass to the chimney. The gases from the ores in course
of calcination are collected in flues f,f,f, Figures 1, 2, and 4, which com-
municate with a condensing apparatus. In calcining a mixture of ores and
common salt the powdered mixture is fed on to the top shelf through the slit
in the arch, Figure 2, by any apparatus capable of a nice adjustment as to
feed and regularity; it accumulates on the first shelf and slips down on to the
second, and so on to the bottom. The shelves gradually increase in heat
towards the bottom. The feed must be regulated according to the nature of
the ore, so that when the mixture reaches the lower shelf it is found on testing
if the ore is a copper ore that all the remaining copper is soluble in water
slightly acidulated with muriatic acid. If some portion of the copper still
remains insoluble the feed must be reduced till it reaches the exact point.
If
The calcined ore is removed from time to time as required by the door a.
the ore shews any tendency to stick to the tiles its descent may be facilitated
by cleaning the shelves by inserting a tool at regular intervals at the sliding
doors 9, 9, 9, 9, beginning at the bottom, and proceeding upwards.
Figures 5, 6, 7, 8, 9, and 10 shew a different arrangement of shelved
furnace for calcining or oxidizing ores, minerals, or metals in a state of powder.
Instead of a small number of large shelves the furnace is divided into a large
number of small shelves curved on the top; these are shewn in the Drawings
as consisting of one piece of the nature of a small retort, but they may be
made of three tiles; I prefer them in one piece. This furnace is also shewn as
worked with gas and hot air. Figures 5, 8, 9, and 10 give different views of
a pair of these furnaces arranged side by side, to shew the proper arrangement
of flues. The gas is admitted to the furnace by the pipe a, Figures 5 and 7,
which terminates in a cast-iron box extending along the front of the
furnace and into which the round fire-clay pipes on the top of the furnace
enter. The gas passes through these pipes and descends through the narrow
flues shewn in dotted lines in Figure 5, and at c, c, c, c, in plan in Figure 9.
The air enters by the butterfly valves d, d, Figure 7, passes under the slope of
the hopper at the bottom of the furnace, up the back slope, and through the
first four rows of shelves, thus serving two very important purposes, cooling

page_text: the finished ore and heating the air. The heated air and gas meet and ignite.
when about to enter the fifth row of shelves, and the flame passes backwards
and forwards through the whole of the shelves, as shewn by the arrows in
Figure 5. The products of combustion pass to the chimney by the flues
e, e, e, e, Figures 5, 8, 9, and 10. The ore or mixture of ore and salt in the
state of coarse powder is introduced into the furnace through the slit between
the two arches at the top of the furnace by means of rollers or screws capable
of nice adjustment; from thence it falls in a continuous or intermittent stream
on to the top tile, shewn in section in Figure 6, which distributes it on the
whole of the shelves. Each shelf can bo cleaned at regular intervals through
the small doors fitted to each, as shewn in section, elevation, and plan in
Figures 5, 7, and 9 .respectively. When the ore reaches the fifth row of
shelves from the bottom it should have attained that exact degree of oxidation
required. If on removing a portion by the small doors and testing it is found
to be too much oxidized, or not enough, the feed must be increased or
diminished, as the case may be. When the proper feed according to the nature.
of the ore has been formed there will be no difficulty in maintaining the
utmost regularity in the results. At least every 12 hours all the small shelves.
should be cleaned, beginning at the bottom and proceeding regularly to the
top. The gases from the ores or mixture of ores and common salt pass off
from the furnace by the two sets of flues, as shewn at f,f,f,f, in Figures 5, 6, 8, 9,
and 10, which are in connection with a condensing apparatus. The doors 9,9,
in Figure 7, are for clearing down the side of the hopper in case the ore
should stick, and to assist in its removal by the door h, h, h, in Figures.
5 and 7.
The two furnaces or kilns represented in Figures 1, 2, 3, and 4 and in
Figures 5, 6, 7, 8, 9, and 10 are essentially close or muffe furnaces, and the
whole of the air admitted to the interior of these furnaces, except when in the
act of clearing down the shelves, must be admitted through the doors a, a, a
in Figures 1, 2, and 3, and through the doors 9, 9, and h,. in Figures 5 and 7.
This is an especial advantage, as all the fumes from the ore are of necessity
carried back into the furnace and on to the condensor. This inward draught
can never be much interfered with, even when cleaning down the shelves, as
only one orifice need be open at a time, and that bears but a small proportion.
to the cubic contents of the furnace. For calcining copper ores, such as
those produced by burning cupreous pyrites, for the manufacture of sulphurio
acid, and which in the burnt state sellom exceed 6 per cent. of sulphur partly
as sulphurous acid, and undecomposed sulphur, and which I usually calcine
with a variable proportion of common salt, or other chloride subliming moro

page_text: or less of the copper as chloride, and washing out the remainder with water
or acidulated water. I prefer for this purpose the furnace shewn in Figures
5, 6, 7, 8, 9 and 10 as I obtain much more regular results and get the
calcined product cooled sufficiently low to prevent gaseous exhalations, and
If the
ready without further cooling to go to the lixiviating tanks at once.
ore is very poor in sulphur, that is to say has been well burnt, and can there-
fore be passed through the furnace more quickly, the cooling shelves may be
increased from 4 to 6 or more rows, and to further assist in cooling the
lowest one or more rows may be made of cast-iron. By means of the valves
for admitting the air and the gas, and the regenerative effect of the hollow
shelves and the flues, the heat in these furnaces or kilus can be regulated to
the greatest nicety and used with the utmost economy. Common furnaces
with coal fires might be used for these furnaces, but owing to the cou-
tinual choking up of the hot flues and shelves with dust, I much prefer to
generate the gases in a separate furnace and conduct them to my furnaces,
as gas.
Another advantage in using these upright furnaces instead of the flat close
furnaces is, that the salt necessary to convert into chlorides the different
metals is very much reduced as the perchloride of iron produced in the early
stages of decomposition parts with its chlorine on the hotter and lower shelves,
and in ascending against the downward current of ore powerfully assists
in the oxidation of the descending mineral. The time therefore is much
shortened, and the quantity of chloride of sodium or other chloride used much
reduced. Metals in the state of powder or very rich reguluses reduced to
powder, when they contain less than 12 per cent. of sulphur, may also be reduced
to the state of oxides very rapidly in these furnaces. Reguluses or matts of
copper, containing arsenic, antimony, bismuth, or tin, may be separated from
these impurities in the following manner:-They are first calcined in the
usual or any other manner, until their sulphur is reduced below 13 per cent.
and more than 5 per cent. They are then reduced to fine powder and mixed
with 2 equivalents of salt to one of sulphur, and passed through the furnace
shewn in Figures 5 to 10. The oxide is examined as it reaches the fifth row of
shelves for these impurities, and the feed regulated accordingly. The whole
of these impurities will sublime as volatile chlorides, carrying some copper
with them; these are all condensed with water, the copper arsenic and part of
the tin being in solution as chlorides, and the antimony and bismuth pre-
cipitating as basic oxides. The calcined regulus will contain some portion
of soluble copper, which is dissolved out with acidulated water, and the oxide
of copper remaining is smelted for copper in the usual or any other manner.

page_text: The conversion of oxides of metals and carbonates of oxides of metals to the
inetallic state without absolute fusion may be effected in three ways,-1st,
by long exposure at a bright red heat in the state of fine powder in intimate
contact with carbonaceous matter, also in fine powder in close vessels; 2nd,
by exposure at a bright red heat in vessel's filled with and supplied with a
current of gases capable of reducing these metals; and 3rd, by exposing oxides
or carbonates of metals, mixed with a minimuin portion of carbonaceous matter
and exposed to a current of gases, capable of reducing oxides of these metals
to the metallic state. Both the furnaces already described, with a slight
alteration of the flues and terminating hoppers, may be used for the pur-
poses of reducing oxides by the two la-t methods. My experience induces
me to prefer the third method for this class of furnace.
I take, for example, the oxide of irou produced when burnt cupreous pyrites
bas been treated in the manner described, and when all the copper has been
washed out of it. This residue I find when properly treated for copper to be a
very pure oxide of iron principally peroxide. This I dry and reduce to very fine
powder, thoroughly mixed with from 3 to 4 cwt. of coal, free from sulphur and
fed in by rollers or other machinery to preferably the furnace shewn in Figures 5
to 10. This furnace is first slightly altered in its mode of working; the door
for drawing is done away with, and the furnace terminates in a hopper with a
slide in the button. The coal gas or carbonic oxide is admitted to the
interior of the furnace immediately below the first row of shelves and ascending
through the current of descending ore. assists in the reduction. The gases
afterwards descend by the flues at the ends of the furnace to the level of the
first row of shelves. The air is admitted where the gas is shewn to enter,
descends through the narrow flues c, c, c, c, at the back of the furnace ant
meets the gas where it enters the first row of shelves and is there ignited,
heating up the shelves as it ascends, or when the reduced iron is required for
precipitation and is required to be cooled before grinding, I terminate the
furnace by several rows of flat cast-iron hollow shelves, through which 1
currents of cold air, this cooling the reduced metal powder in an atmosphere
of carbonic oxide gas and it is withdrawn through the tapered hopper cold.
To prevent the entrance of air into the interior of the furnace a pressure of
gas should be maintained inside so that when any one of the small doors is
taken off the gases should blow out. After the flame has passed through all
the shelves it is taken down to the large flue e, which should be much enlarged
as the flues f, f. Figure 5 will not in this case be required. The reduce
metallic iron will reach the hopper in the state of fine metallic silky flakes, and
should be received in an air-tight cast or wrought-iron receiver. If to be used for.
pass

page_text: the purposes of precipitating copper and other metals it should be cooled out
of contact of the air and again when cold ground to powder. If proposed
to be made into wrought iron or cast steel it should be whilst still red hot
pressed either by hydraulic pressure or by sudden blows into blocks; these
blocks may be at the same time divided into segments of a circle by inserting
into the empty receiver slips of wrought iron to within a trifle of the depth
to which it is found practicable to compress the iron sponge. To make
wrought iron of very superior quality the blocks whilst still red hot are turned
out of the receiver and brought to a welding heat in a gas heating or other
suitable furnace, hammered and rolled exactly as puddled blooms. When it is
desired to make cast steel direct, the compressed blocks are, whilst still hot,
transferred from the receiver to a properly constructed gas or other furnace,
and melted on a carbon bottom. When completely melted the slag is skimmed
off and the steel refined and purified by adding ferro-manganese, and brought
to any degree of hardness or softness by adding charcoal, pig iron, or pure
scrap iron, as may be necessary. When the steel is perfectly still and brought
to the proper state it is then cast into the required shape. Mixtures of the
oxides or carbonates of iron and manganese, titanium, chromium, or other
metal may be reduced in the same manner. For reducing these oxides or
carbonates or mixtures of either by means of solid carbonaceous matter, I prefer
to use the furnace shewn in Figures 11, 12, 13, 14, 15, and 16. This furnace
is also worked with gas and hot air on the well-known reversible regenerative
system, the flame being caused by the reversing valves shewn at a, Figures 11
to 16, to traverse the heating spaces between the reducing chambers from
right to left and from left to right, alternately at regular fixed intervals. The
reducing chambers b, b, b, b, Figures 11, 12, 14, and 16, are completely
filled with pure oxide of iron, with from 4 to 6 cwt. of coal or other
carbonaceous matter free from sulphur, all reduced to fine powder and
intimately mixed. The mixture is introduced through the holes on the top
of each chamber, at c, c, c, c, Figures 11, 14, and 16. The furnace is first
brought to a uniform bright red heat, then the whole of the chambers are
charged, and the heat continued at bright redness for from 12 to 20 hours.
A sample is from time to time withdrawn from each chamber by the sampling
doors d,. d, d, d, Figures 14 and 16, and tested by means of a standard
solution of copper, which will indicate the quantity of iron in the metallic
state by the amount of copper precipitated. The sample must be cooled out of
contact with the air and reduced to fine powder. When it is found that
practically the whole of this iron or other metal has been reduce to the
metallic state the cast or wrought-iron receiver is brought under the

page_text: discharging hole and the pipe connecting the two luted up, the plug or slide
covering the discharging hole, shewn at d, d', Figures 11, 14, and 16, is then
removed, and the reduced ore discharged into the receiver. The double door
shewn at e, e, e, Figures 12, 14, and 16, admits rakes or other tools for this
purpose. Care must be taken to clean out each chamber thoroughly each
time, as the reduced iron if allowed to remain will rapidly corrode the brick-
work. If the reduced iron is required for the purposes of precipitation care
must be taken not to use too intense a heat, which produces shots of metal in
the mass; a slow, well sustained heat produces a fine soft silky sponge which
when cooled out of contact of air grinds readily to a fine powder without
residue.
If the object in view is to produce wrought iron or cast steel the softening
of the charge is not so objectionable, but it must not be carried too far, as it is
apt to adhere to the brick work of the chambers. I rake the reduced metal
into a strong cast-iron cylinder hooped outside with iron bands; the cylinder
is slightly wider at the bottom than the top, and rests on a strong cast-iron
platform which has wheels fitted to it, and forming a carriage which runs ou
cast-iron plates under the archway f, f, f, f, Figures 13, 14, 15, and 16. The
cylinder fits into a recess on the platform of the carriage which is luted with
clay or sand. In the bottom of the cylinder are placed strips of stout wrought-
iron radiating from the centre and reaching to within of an inch of the
distance to which it is found necessary to compress the reduced iron. The
cylinder has a moveable lid with a bole in the centre, and into this hole is fitted
a tube which communicates with the discharging hole. The charge is raked
into the cylinder, which it should nearly fill; the wagon with the cylinder is
then withdrawn, a small cover being substituted for the pipe; a small quantity
of coal or charcoal powder is thrown into the cylinder by the small hole and the
contents levelled; the cover is then removed, and a strong piston fitting the
cylinder is either forced down by percussion or by hydraulic power. When
sufficiently con pressed to admit the air into the solid blocks which whilst hot
would re-oxidize the iron, they are ejected from the cylinder by raising it off
its carriage, when the disc of metal will be found to be divided into as many
segments as there were strips of metal introduced.
Each of the chambers shewn in the Drawing is calculated to produce about a
ton of reduced metal at each charge; I prefer to draw this into two cylinders,
and divide each compressed disc into about 8 pieces of 11 cwt., each which
are easily handled. These whilst still red hot are thrown into a gas or other
suitable melting furnace with a carbon bottom aud rapidly melted, as already
described. When required for wrought iron, less solid carbonaceous matter

page_text: should be used in the reduction chambers, and the compressed blocks should
be whilst still red hot transferred to a heating furnace, and treated exactly as
ordinary blooms.
Several other metals and alloys of metals may be produced in the same
manner as already described, first reducing by long exposure to a bright red
heat in close vessels in contact with solid carbon, both being in the state of
fine powder; secondly, compression out of contact with air; and, thirdly, rapid
melting. Hematites and other rich ores of iron I also convert by the means
described into wrought iron or cast steel direct from the ores..
Figures 17, 18, 19, 20, and 21 shew another arrangement of furnace with
leaved chambers for reducing oxides by contact with solid carbonaceous
matter. This furnace consists of 10 tall narrow reducing chambers heated by
gas and by means of 11 flues, the gas and air being admitted to each flue
separately and independently of each other; the furnace or block may consist
of any number of reducing chambers; this arrangement of furnace dispenses
with reversing valves.
The air and gas are admitted at a, a, Figures 19 and 21, and are caused
to traverse up and down the three series of pipes before entering their special
flues b, b, Figures 19 and 20; they are then admitted separately into each
flue, as shewn at c, c, Figure 19. The flame passes up the narrow flue to the
top, and the waste heat passes away through the flues d, d, d, d, to the right
and left, and after passing up and down and around the pipes in the chambers
e, e, e, e, Figures 17, 19, 20, and 21, passes to the large flue leading to the
chimney, as shewn at f, f, Figure 17.
The pipes in the first chamber into which the waste heat and gases enter
should be made of fire-clay, and if the heat is still too great also in the second
chamber, but where cast-iron pipes are not injured by the intense heat, I
prefer to use them. When the whole of the chambers have been heated up
to a uniform degree one chamber after the other is filled through the charging
holes 9, 9, Figure 20, with the mixture of oxide and carbonaceous matter,
and when reduced is discharged into the close receiver, already described,
through the hole in the bottom, shewn at h, Figure 20.
I wish it to be distinctly understood that I am aware that a furnace with
solid bars of prismatic form somewhat similar to the furnace herein-before
described and shewn in Figures 5, 6, 7, 8, 9, and 10 has been already
patented for the purpose of roasting pyrites without fuel, and I do not there-
fore claim the construction of the furnace referred to; I am also aware that
furnaces similar to those shewn at Figures 11, 12, 13, 14, 15, and 66 have
been constructed and worked by. means of an ordiuary coal fire at one end,

page_text: and that they have failed to produce anything like regular or satisfactory
results; the chamber next the fire getting too much heat fuses the iron and
destroys the brickwork, and those furthest from the fire not getting enough of
heat are never thoroughly reduced. By the alternate heating by a pure
flame at either end in turns a uniform heat is maintained over the whole of
the chambers, and by means of the valves the degree of heat can be regulated
to the greatest nicety and without injury to the brick work, and on these points
entirely depends the economic success of the whole process.
What I claim is,-
1st, constructing furnaces, as herein-before described and illustrated in
Figures 1, 2, 3, and 4, with hollow or double shelves, and the employment
thereof for oxidizing ores, minerals, reguluses, and metals, substantially as
described.
2nd, the modification of such furnace, as herein-before described, and the
employment thereof when so modified for reducing oxides and salts of metals,
as berein-before described.
3rd, constructing furnaces, substantially as herein-before described and
illustrated in Figures 5 to 10 with small hollow shelves, having their upper
surfaces curved, and the employment thereof for oxidizing ores, minerals,
reguluses, and metals, substantially as described, especially when they contain
12 per cent. and less of sulphur.
4th, the modification of such furnace, as herein-before described, and the
employment thereof when so modified for reducing oxides and salts of metals,
as herein-before described.
5th, the reduction of oxide of iron and other metals by the means and in
the manner substantially as herein-before described.
6tb, the construction of furnaces, substantially as herein-before described
with reference to Figures 17 to 21, and the employment thereof for reducing
oxides of metals.
7th, the manufacture of wrought-iron and cast steel direct from the ores,
by the means and in the manner substantially as herein-before described.
8th, the purification of copper ores and reguluses from arsenic, tin, antimony,
and bismuth; substantially as herein-before described.
9th, the calcining by means of furnaces, constructed substantially as repre-
sented in Figures 1, 2, 3, and 4 and Figures 5, 6, 7, 8, 9, and 10, of ores
containing less than 12 per cent. of sulphur (that is to say, too little sulphur
to maintain the heat necessary for calcination) or of burnt ores when mixed
in coarse powder with common salt or other suitable chloride, whereby a
portion of the copper and other metals and gaseous products is volatilized and

page_text: condensed, and the greater portion of the copper is rendered soluble in water
or water slightly acidulated with muriatic acid or mixed with perchloride
of iron.
In witness whereof, I, the said William Henderson, have hereunto set
my hand and seal, this Fourth day of October, One thousand eight
hundred and sixty-seven.
WN. HENDERSON. (L.S.)
WM. HENDERSON. (L.S.)