Improvements in the Manufacture of Oxide of Iron, and in Means applicable for use in such Manufacturé.
Year: 1893

page_text: Date of Application, 23rd Feb., 1893
Complete Specification Left, 23rd Nov., 1893—Accepted, 23rd Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Oxide of Iron, and in Means
applicable for use in such Manufacturé.
I, HENRY WILLIAM HEMINGWAY, of 60, Mark Lane, in the City of London,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
This invention relates to the conversion of copperas into oxide of iron (known in
the colour trade as "Venetian red "and under other names), and to the construction
of furnaces or kilns adapted for used in the process.
According to the method of manufacture at present commonly in use, green
copperas liquor is boiled down, and the copperas obtained is ground and burnt in
ordinary furnaces; or is broken up, placed in " saggers" which are then stacked in
a kiln, and burnt.
As the result of experiment, I have found that by subjecting the copperas in a
solid state to the burning or retorting process, economy is effected and a superior
product is obtained, owing to the greater conductivity and consequent more even
heating of the material throughout its mass when in such solid condition, and the
avoidance of the tendency for the outer or more exposed parts to become over-
heated, as frequently occurs when the material is treated in a powdered, granular or
broken state, the portions exposed to excessive heat being either spoilt or injured
by reason of the colour becoming too dark. Owing to this want of uniformity,
the product has to be sorted by hand, and the different shades of colour
separated.
«
"
In carrying out my invention, I boil down the green copperas liquor, and cast the
copperas into blocks of a size and shape corresponding with the oven, retort or
sagger" in which the same is to be burnt. I find blocks about twelve inches in
diameter and four inches thick a convenient size when intended for burning in
saggers," but blocks of much larger size may be treated in a furnace or kiln of
the improved construction hereinafter described; and in casting such block or slab,
I introduce a hook- or eye-ended metal bar for the purpose of affording additional
strength to the block, and for facilitating its manipulation whilst being lowered into
the kiln.
A furnace or kiln adapted for use in the manufacture of oxide of iron from
copperas in the form of solid blocks or slabs and constructed according to my
improved method comprises a series of chambers or pockets alternating with flues
or passages; the former being designed for the reception, and corresponding with
the shape, of the slabs of copperas, whilst the intervening flues serve for the
conduct of the heating gases. By the employment of this mode of construction,
both sides of each slab of copperas are subjected to the influence of the hot gases,
without however being exposed to their direct action. Moreover, the fumes
evolved from the copperas whilst undergoing decomposition, and consisting for the
most part of sulphurous and sulphuric acid gases, are kept separate from the
heating gases and may be passed through scrubbers or equivalent appliances and
condensed.
With a view to facilitating the removal of the material from the pocket or
chamber of the kiln in which it has been treated, I arrange the bottom in such a
manner that it may be readily removed or dropped. With this object, the floor
may be pivoted at its rear end and supported at its front end on a removable bar,
catch or other supporting or suspending device, which, upon being released, allows
the floor to assume a downwardly-inclined position, thus releasing the material.
This, breaking up, glides down the incline and may be received in a barrow or
other receptacle. The floor is then restored to its working position, and the pocket

page_text: or chamber re-charged from above with a fresh block or blocks of copperas without
rendering the cooling down of the furnace necessary.
The gases for heating may be derived from the combustion of ordinary fuel or of
creosote or other inflammable oil or from producer- or water-gas; and may be caused
to traverse one, two or more, of the passages intervening between the chambers in
which the blocks or slabs of copperas are placed.
Dated the 22nd day of February 1893.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Oxide of Iron, and in Means
applicable for use in such Manufacture.
I, HENRY WILLIAM HEMINGWAY, of 60, Mark Lane, in the City of London,
Manufacturer, 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:-
This invention relates to the conversion of copperas into oxide of iron (known in
the colour trade as "Venetian red" and under other names), and to the construction
of furnaces or kilns adapted for use in the process.
According to the method of manufacture at present commonly in use, green
copperas liquor is boiled down, and the copperas obtained is ground and burnt in
ordinary furnaces; or is broken up, placed in "saggers," which are then stacked
in a kiln, and burnt.
66
As the result of experiment, I have found that by subjecting the copperas in a
solid state to the burning or retorting process, economy is effected and a superior
product is obtained, owing to the greater conductivity and 'consequent more even
heating of the material throughout its mass when in such solid condition, and the
avoidance of the tendency for the outer or more exposed parts to become over-
heated, as frequently occurs when the material is treated in a powdered, granular
or broken state, the portions exposed to excessive heat being either spoilt or injured
by reason of the colour becoming too dark. Owing to this want of uniformity,
the product has to be sorted by hand, and the different shades of colour separated.
In carrying out my invention, I cast the copperas into blocks of a size and shape
corresponding with the oven, retort or sagger" in which the same is to be burnt.
The melting and casting of the copperas into blocks of suitable form produces
homogeneousness and uniformity of structure throughout the mass, and this ensures
even heating and consequent uniformity in the colour of the oxide. Such result
cannot be obtained from burning ordinary. lumps and masses of this material,
owing to their not being uniform in structure, form or dimensions. I find blocks
about twelve inches in diameter and four inches thick a convenient size when
intended for burning in "saggers," but blocks of much larger size may be treated
in a furnace or kiln of the improved construction hereinafter described. After the
copperas is converted by the heat into oxide, the latter is removed from the furnace,
and ground in the usual manner. In casting each block or slab, I introduce a hook-
or eye-ended metal bar for the purpose of affording additional strength to the
block, and for facilitating its manipulation whilst being lowered into the kilo. The
hook- or eye-ended metal bars may be used repeatedly.
Of course the rectangular form of the block is not essential to the carrying out
of my invention, nor is it essential that the block shall be of any particular size. I
prefer, however, the simple rectangular form, and also prefer that all the blocks
burned at one time shall be of the same dimensions.
The accompanying drawings show a furnace or kiln adapted for use in the
manufacture of oxide of iron from copperas in the form of solid blocks or slabs
and constructed according to my improved method.

page_text: Fig. 2 is a longitudinal section on the line 2, 2 in Fig. 5.
Fig. 3 is a horizontal section on the line 3, 3 in Fig. 1.
Fig. 4 is a cross section on the line 4, 4.
Fig. 5 is a similar view on the line 5, 5.
Fig. 6 is a view corresponding with Fig. 5, but showing a different arrangement
for firing the furnace.
The improved furnace or kiln comprises a series of chambers or pockets A
alternating with flues or passages B. The chambers A are designed for the
reception of the copperas, which may be in blocks or slabs corresponding in shape
with the said chambers. The intervening flues B serve for the conduct of the
heating gases. By the employment of this mode of construction, both sides of
each block or slab of copperas are subjected to the influence of the hot gases,
without however being exposed to their direct action. Moreover, the fumes
evolved from the copperas whilst undergoing decomposition, and consisting for the
most part of sulphurous and sulphuric acid gases, are kept separate from the
heating gases and escape through the openings a into the pipe or flue A', whence
they may be passed through scrubbers or equivalent appliances and condensed.
A are removable tiles for covering the chambers or pockets A. Openings bare
left in the centre wall C for the passage of the heating gases from the front flues B
to the back flues B. The fuel-nozzles are passed through the apertures B. Or the
burning fuel may traverse a flue B* in the centre wall C and pass to the flues B
through apertures such as 6x. Or the fuel-nozzles may project through apertures
in the bottoms of the front flues B. The products of combustion escape through
flues into a main flue B2, whence they are conducted to the atmosphere.
B³ are dampers for altering the available area of the flues 6', so as to regulate the
heating of the furnace.
With a view to facilitating the removal of the material from the pockets or .
chambers A, I arrange the bottom of each chamber in such a manner that it may
be readily removed or dropped. With this object, the floor or bottom A³ may be
pivoted at its rear end on a pin d and supported at its front end on a removable bar
or catch, such as e, or other supporting or suspending device, as for instance a rod
or piece of gas-pipe placed between the floor A3 and the ground, which, upon being
released, allows the Hoor A³ to assume a downwardly-inclined position, as shown on
the left-hand side of Fig. 4, thus releasing the material. This, breaking up, glides
down the inclined floor or bottom and may be received in a barrow or other
receptacle. The floor is then restored to its working position, and the pocket or
chamber A re-charged from above with a fresh block or blocks of copperas without
rendering the cooling down of the furnace necessary. The brickwork may be
braced in the ordinary manner.
The gases for heating may be derived from the combustion of ordinary fuel or of
creosote or other inflammable oil or from producer- or water-gas; and may be
caused to traverse one, two or more of the passages B intervening between the
chambers A in which the blocks or slabs of copperas are placed.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. The improved method of manufacturing oxide of iron, substantially as herein
described.
2. The improved method of making oxide of iron from copperas, which consists
in melting the copperas and casting it in the form of blocks of homogeneous
structure having the proper dimensions to fit the chambers or pockets in which they
are to be burned, and burning the blocks until they are converted into oxide of iron,
substantially as herein described.
3. The improved furnace or kiln constructed substantially as described with
reference to the accompanying drawings.
4. The improved furnace or kiln, constructed substantially as herein described

page_text: and comprising a series of narrow chambers or pockets having at their tops
openings each of approximately the same area as the chamber beneath and
furnished with a removable cover, said chambers alternating with flues for hot
gases; the chambers being by preference provided with a conduit for carrying off
the vapours or gases evolved, and the flues with a conduit for carrying off the waste
products of combustion.
5. In a furnace or kiln, the employment of a narrow chamber open at the top for
the admission of raw material in the form of solid blocks, and provided with a
movable floor to permit the discharge of the product below; said chamber having
on either side flues for hot gases, a conduit for carrying off the vapours or gases
evolved from the material whilst under treatment, and a cover adapted to close the
inlet.
Dated the 20th day of November 1893.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.