IMPROVEMENTS IN THE MANUFACTURE OF SULPHATES
Year: 1872

page_text: LETTERS PATENT to Sidney William Rich, of Chenics Street, in
the County of Middlesex, Analytical Chemist, for the Invention
of TWPRAVEKRETS TEP
MAWNDA A MOD "
PROVISIONAL SPECIFICATION left by the said Sidney William Rich
at the Office of the Commissioners of Patents, with his Petition,
on the 25th April 1872.
I, SIDNEY WILLIAM RICH, of Chenics Street, in the County of
Middlesex, Analytical Chemist, do hereby declare the nature of the
said Invention for “IMPROVEMENTS IN THE MANUFACTURE OF SULPHATES," to
be as follows :—
This Invention relates to the conversion of the peroxide of iron
and alumina in burnt or waste shale or other similar material into
sulphates.
The object is effected by bringing the moist material into contact
in suitable vessels with sulphurous acid, by the reaction which ensues
between the sulphurous acid and the peroxide of iron sulphuric acid

page_text: and protoxide of iron are produced; these unite at the moment of
their production giving rise to protosulphate of iron which is in part
or wholly decomposed by the alumina, forming a greater or less quantity
of sulphate of alumina and free protoxide of iron. The sulphate of
alumina and the remaining sulphate of iron may then be dissolved out 5
by means of water and the solution evaporated, or its constituents
recovered in any suitable manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sidney William Rich in the Great Seal Patent
Office on the 25th October 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SIDNEY
WILLIAM RICH, of Chenies Street, in the County of Middlesex,
Analytical Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of April, in the year of 1
our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Sidney William Rich, Her special licence
that I, the said Sidney William Rich, my executors, administrators, and
assigns, or such others as I, the said Sidney William Rich, 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 THE
MANUFACTURE OF SULPHATES," upon the condition (amongst others) that
I, the said Sidney William Rich, 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 I, the said Sidney William Rich, do hereby

page_text: same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :-
This Invention relates to the conversion of the peroxide of iron
and alumina in burnt or waste shale or other similar material into
sulphates.
The object is effected by bringing the moist material into contact in
suitable vessels with sulphurous acid, by the reaction which ensues
between the sulphurous acid and the peroxide of iron sulphuric acid and
protoxide of iron are produced; these unite at the moment of their
production giving rise to protosulphate of iron, which is in part or
wholly decomposed by the alumina, forming a greater or less quantity
of sulphate of alumina and free protoxide of iron. The sulphate of
alumina and the remaining sulphate of iron may then be dissolved
out by means of water and the solution evaporated or its constituents
recovered in any suitable manner.
The material I prefer to use is the recently burnt shale or schist while
still retaining the heat arising from its combustion, and while in this
condition I bring it into contact with a current of sulphurous acid gas,
air, and steam.
.
:
I prefer to effect my purpose in the following manner :-I cause the
shale or schist to burn in and above a circular cell built of brick or stone,
about twenty or twenty-five feet high, and ten feet in diameter inside.
The walls of the cell should be about five feet thick at the top, so that
the total diameter at the top shall be about twenty feet.
be built of stone outside and brick inside and the space
and stone filled with earth or other heavy rubbish.
of the cell are several openings about two feet in
with doors for the removal of the contents of the cell. I find four such
openings to be a suitable number. for a cell having an inside diameter
of ten feet.
These walls may
between the brick
At the lower part
diameter, provided
I facilitate a proper combustion of the shale or schist by piling it
above the cell in the form of a heap after the cell itself shall have been
filled and by allowing the heap to cover the walls of the cell, this heap
may be made to have a diameter at its base of about twenty feet. As
the material is withdrawn from the openings at the lower part of the
cell the heap gradually sinks into the cell when it must be kept up to
its original size and the combustion maintained by the supply of fresh

page_text: shale or schist from above. The combustion of the shale or schist having
at the beginning been started by means of wood or coal may be
maintained by this means without any further fuel while the material
may be withdrawn at intervals from below. By thus withdrawing the
material from below the contents of the cell are kept in a loose state,
and thus rendered more permeable to the sulphurous acid gas, air, and
steam, the introduction of which I now proceed to describe. As the
contents of the cell must be at a high temperature before my require-
ments can be fulfilled, I continue withdrawing material from the bottom
and supplying fresh shale or schist to the top until the material with-
drawn is so hot as to hiss on the application of cold water, when this
stage is reached I close the openings below and cause the introduction
of a current of sulphurous acid gas, air, and steam. In order to prevent
the fire at the top from burning itself out a coating of fresh schist or
shale is laid on at intervals. The current of sulphurous acid gas is
produced by burning pyrites in furnaces or by other known means,
and the gas is forced into the cell by means of a fan or fans working
in the flue or flues which connect the sulphur furnaces with the cell;
the current of sulphurous acid gas is forced into the lowermost portion
of the cell, so that the gas may traverse the whole mass of material.
In addition to the current of sulphurous acid gas I cause the
introduction at the lower part of the cell of a jet or jets of steam from a
steam boiler, and the supply of steam is determined by the smell issuing
from the upper part of the cell at the surface of the heap, if thero is a
strong smell of sulphurous acid gas more steam must be admitted, if
there is no smell, or only a slight smell of sulphurous acid gas, the
supply of steam may be diminished or even as occasion demands
quite stopped. I also cause the introduction of a current of atmo-
spheric air at the lower part of the cell by means of a fan or fans
drawing half the volume drawn by the fan or fans used for the sulphur
furnaces.
The result of the joint action of sulphurous acid gas, air, and steam
on the hot burnt shale is the production of sulphate of alumina, con-
taining a small proportion of sulphate of iron and also some sulphate of
magnesia. This operation is continued until the persistent escape of
sulphurous acid gas from the surface of the heap shows that the contents
have been fully acted upon, and when this occurs a portion of the
contents may be periodically removed from the openings below, the.

page_text: supply of fresh shale being kept up from above. It is well to stop the
admission of sulphurous acid gas while the doors are opened for the
withdrawal of material.
In the event of an excess of steam being admitted a fluid solution is
formed to some extent and sinks to the bottom of the cell; as this liquor
is valuable the floor of the cell should be cemented and furnished with
a drain so that the liquor may be run off and collected, indeed it is
in some cases found useful to favour the formation of such a liquor. By
the above process a continual action is kept up allowing the periodical
removal of a portion of the salts formed. The substance removed may be
dissolved in water in order to separate insoluble matters, and the solution
obtained used for the manufacture of alum, sulphate of alumina, Epsom
salts, and for other known processes. Simply evaporated to a solid
consistence it forms an excellent material wherewith to treat sewage.
•
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,
treating burnt or waste schist or shale or other similar material with
sulphurous acid gas in order to convert the bases contained in these
substances into sulphates, substantially as described.
In witness whereof, I, the said Sidney William Rich; have here-
unto set my hand and seal, this Twelfth day of October, in the
year One thousand eight hundred and seventy-two.