IMPROVEMENTS IN THE MODE OF AND APPARATUS FOR THE REDUCTION OF SULPHATE OF IRON CRYSTALS
Year: 1867

page_text: LETTERS PATENT to Edward Madge, of Swansea, in the County of
Glamorgan, Gentleman, for the Invention of "IMPROVEMENTS IN THE
MODE OF AND APPARATUS FOR THE REDUCTION OF SULPHATE OF IRON CRYSTALS."
-Partly a communication from abroad by Charles Madge, of Carrizal:
Bajo, in the Republic of Chili.
Sealed the 5th May 1868, and dated the 13th November 1867..
PROVISIONAL SPECIFICATION left by the said Edward Madge at the
Office of the Commissioners of Patents, with his Petition, on the
18th November 1867.
I, EDWARD MADGE, of Swansea, in the County of Glamorgan, Gentleman,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MODE OF AND APPARATUS FOR THE REDUCTION OF SULPHATE OF IRON CRYSTALS,'
to be as follows:-
The object of this Invention is to effect the reduction of sulphate of iron
crystals, commonly called green vitriol, in an economical manner. This
product is largely obtained from the spent liquor or pickle used in the
manufacture of tinned or terne plates, and it is mainly to the utilization of
the product so derived that the Invention is directed. The sulphate of iron is.

page_text: first placed in a furnace or drying pan and beat is applied thereto from above,
the charge during the process of drying being exposed as much as possible to
the action of the air. When the whole or nearly the whole of the combined
water is evaporated the product will be a soft porous substance retaining more
or less the form of the original crystals. The charge thus prepared is then
calcined on a hearth heated from below, but so arranged as to admit the air
freely to the charge. The calcination is continued at a sub red heat until the
charge has absorbed a sufficient quantity of oxygen, which will be known by
its assuming a light brown yellow color, and if not already reduced to powder
it will crush with slight pressure being applied thereto, when it will be in the
best possible form for being submitted to distillation; the charge is next
placed in retorts, and sulphur fumes are distilled off in the ordinary way.
These fumes may be condensed in the usual manner in a leaden chamber, or
in simple condensers, as fuming sulphuric acid; the residue is peroxide of
iron.
The above described operations may be effected in any approved furnace or
furnaces, but it is preferred to use the following arrangement, which allows
of the waste heat generated for the distillation of the sulphur being used for
drying and calcining the crystals. A set of. retorts is arranged in a closed
chamber or oven to which the flames and heated gases of an adjacent fire are
admitted. Round the retorts the heat circulates, and it then escapes to a
borizontal flue above this flue is situated the calcining hearth, and below it
the heating or drying pan. The heated gases in passing from the retort oven
to the chimney will thus serve to prepare the sulphate of iron for the distilling
operation.
i
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Madge in the Great Seal Patent Office on the
18th May 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
MADGE, of Swansea, in the County of Glamorgan, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of November, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year
of Her reign did, for Herself, Her heirs and successors, give and grant unto
me, the said Edward Madge, Her special licence that I, the said Edward
Madge, my executors, administrators, and assigns, or such others as I, the
•

page_text: said Edward Madge, 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 "IMPROVE-
MENTS IN THE MODE OF AND APPARATUS FOR THE REDUCTION OF SULPHATE
OF IRON CRYSTALS," being partly a communication, upon the condition
(amongst others) that I, the said Edward Madge, my executors or adminis-
trators, 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 I, the said Edward Madge, do hereby declare
the nature of the said Invention, and in what manner the same is be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
The object of this Invention is to effect the reduction of sulphate of iron
crystals, commonly called green vitriol, in an economical manner. This product
is largely obtained from the spent liquor or pickle used in the manufacture of
tinned or terne plates, and it is mainly to the utilization of the product so
derived that the Invention is directed. The sulphate of iron is first placed
on a drying plate and heat is applied thereto from above, the charge during
the process of drying being exposed as much as possible to the action of the
air. When the whole or nearly the whole of the combined water is evaporated
the product will be a soft porous substance retaining more or less the form of
the original crystals. The charge thus prepared is then calcined on a hearth
heated from below, but so arranged as to admit the air freely to the charge.
The calcination is continued at a sub-red heat until the charge has absorbed
a sufficient quantity of oxygen, which will be known by its assuming a light
brown yellow color, and if not already reduced to powder it will crush with
slight pressure being applied thereto, when it will be in the best possible form
for being submitted to distillation. The charge is next placed in retorts
and sulphur fumes are distilled off in the ordinary way. These fuines
may be condensed in the usual manner in a leaden chamber, or in simple
condensers, as fuming sulphuric acid. The residue is peroxide of it on.
The above-described operations may be effected in any approved furnace or
furnaces, but it is preferred to use the arrangement shown in the accompanying
;

page_text: Drawing, Fig. 1 being a longitudinal section of an improved construction of
furnace designed for carrying out the above-described operation, and Fig. 2
a transverse section of the same.
A, Fig. 1, is the grate of the fire chamber, from which the heat for the
drying, calcining, and distilling operations is derived; B is the fire-door; C is
a brick chamber containing a set of retorts D, D, the number and arrangement
of which may vary according to circumstances. The flame and heated gases
pass from the fire-place through flues c, c, to the chamber C, and after
circulating around the retorts D escape into a horizontal flue E which is con-
nected with a chimney F. This flue E is formed of plates of iron, and a
damper G is provided for regulating the draft of the fire and the heat of the
flue. The plates forming the top of the flue constitute the hearth on which
the sulphate of iron crystals are to be calcined, and the preparatory drying of
the crystals is effected on a plate H situate below the flue and from which the
heat is reflected on to the material spread upon the plate H. To regulate the
drying action this plate or hearth H is made adjustable vertically, so that it may
be brought nearer to or moved further from the flue as circumstances may require.
In the ends of the retorts orifices are made to receive pipes I which lead to a
.condenser, and are for the purpose of conducting off the sulphur fumes as they
are generated in the retorts, and discharging them into the condenser.
The mode of working with the above described apparatus is as follows:-
The sulphate of iron crystals are first placed on the plate H to dry, and while
drying they must occasionally be turned over and over to present the mass
to the action of the air, care must also be taken to prevent the crystals from
melting in the water of crystallization by lowering the plate if any tendency to
melt is shewn. The crystals are soon reduced to a light spongy or pumice
stone appearance, and they will then readily fall into a white powder. This
powder is then to be put on the calciner plate, and when it has assumed a
brownish-yellow appearance, it has absorbed a sufficiency of oxygen to be
transferred to the retorts. The charge on the calciner may be brought to a
low red heat without losing any of its sulphuric acid. The retorts charged
with the calcined crystals are to be "driven" until all sulphuric acid ceases to
be distilled. The residue is oxide of iron which is suitable for a pigment.
From the foregoing explanation it will be understood that the above
described arrangement of apparatus allows of the waste heat generated for
the distillation of the sulphur fumes being used for drying and calcining the
crystals, and that thus a considerable economy is secured.
Having now set forth the nature of the Invention of "Improvements in the
Mode of and Apparatus for the Reduction of Sulphate of Iron Crystals," and

page_text: explained the manner of carrying the same into effect, I wish it to be under-
stood that under the above in part recited Letters Patent, I claim,―
First. The drying, calcining, and distillatory process for reducing or
converting sulphate of iron crystals as above described.
And, secondly. The use of the apparatus above described for carrying the
improved reducing process into operation.
In witness whereof, I, the said Edward Madge, have hereunto set my
hand and seal, the Ninth day of May, in the year of our Lord One
thousand eight hundred and sixty-eight.
EDW. MADGE. (L.S.)