IMPROVEMENTS IN THE MANUFACTURE OF CHLORINE
Year: 1858

page_text: LETTERS PATENT to James Shanks, of St. Helens, in the County of
Lancaster, Manufacturing Chemist, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF CHLORINE."
Sealed the 25th February 1859, and dated the 7th September 1858.
PROVISIONAL SPECIFICATION left by the said James Shanks at the
Office of the Commissioners of Patents, with his Petition, on the 7th
September 1858.
I, JAMES SHANKS, of St. Helens, in the County of Lancaster, Manu-
facturing Chemist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF CHLORINE," to be as follows:-
First, in substituting chromate of lime in place of the oxide of manganese,
which is generally used in the process for obtaining chlorine from hydro-
chloric acid.
Secondly, in recovering the chromate of lime by decomposing the chloride
of chromium (formed by the previous process) by means of lime, and roasting
the mixture of oxide of chromium and lime in a furnace.
Firstly, I claim the use of chromate of lime instead of oxide of manganese
in the production of chlorine.
Secondly, I claim the mode of recovering the chromate of lime after it has
been used in the production of chlorine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Shanks in the Great Seal Patent Office on the 26th
February 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
SHANKS, of St. Helen's, in the County of Lancaster, Manufacturing Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of September, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said James Shanks, Her special licence that I, the said James Shanks, my
executors, administrators, and assigns, or such others as I, the said James
Shanks, 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 MANU-
FACTURE OF CHLORINE," upon the condition (amongst others) that I, the said
James Shanks, 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
Scal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Shanks, do hereby declare 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,
that is to say.
In the production of chlorine on a large scale, manufacturers have hitherto
confined themselves to the use of binoxide or sesquioxide of manganese as a
medium for eliminating this substance from bydrochloric acid. The manga-
nese of commerce generally contains much iron and other impurities, which
are dissolved by the hydrochloric acid, and therefore a greater quantity of the
acid is required than what is necessary for the manganese alone. When the
resulting chloride of manganese is wanted for producing chlorine again,
difficult and complicated processes are required for separating the manganese
in a sufficient state of purity to be suitable for further use.
My Invention or improvement consists in the use of chromate of line as a

page_text: medium for the production of chlorine from hydrochloric acid, which not only
yields chlorine in a state of purity, but the resulting solution of the chloride of
the metal (chromium) is so easily and simply decomposed, and the metal
separated from the hydrochloric acid, that it is at once brought into a state'
whereby the metal may be again oxidized in the course of a few hours.
Having thus described the nature of my Invention, I shall now explain the
process in detail:-I place a quantity of chromate of lime in a stone or other
suitable generator or still (similar to those in common use in the manufacture
of chloride of lime or bleaching powder); I then add to this as much hydro-
chloric acid as will decompose the chromate of lime, which point will be easily
ascertained by the liquid becoming of a beautiful grass green colour. The
charge in the still will work very well, and yield a gradual and steady supply
of chlorine until more than one half has been expelled; then it may be
desirable to apply heat by the usual means of steam or otherwise, either
internally or externally, as is commonly practised in bleaching powder stills in
order to drive off the last portions of chlorine.
The next step of the series of operations is to run off the contents of the
still or stills (which is a solution of chloride of calcium and chloride of
chromium) into a large open tank or receiver, made of stone or any other
suitable material; a quantity of water, the hotter the better, is then to be
added, and the whole well mixed together. Lime previously well slaked,
and I prefer it to be in the state of milk of lime, is to be added to the
liquors in the tank while being well stirred with a paddle until the free acid.
is just neutralized. Then as much more lime (in the state of milk of lime)
should be added as will first of all precipitate the oxide of chromium, and a
further quantity added sufficient to combine with the chromic acid which will
be formed in the next operation.
The remaining step of these processes consists in allowing the precipitate to
subside well, which will be in an hour or two; and when the resulting chloride
of calcium in solution is run off from the precipitate of chromic oxide and
lime, the latter requires to be as well drained as may be, by tapping the tank
at the bottom or throwing the whole of the precipitate on a drainer. Thus
the precipitate having become a little stiff is now to be thrown into a furnace,
either open, reverberatory, or close oven form. I prefer the latter, having
apertures for the free admission of atmospheric air into the bed or hearth
whereon the material is placed. By keeping up the heat of this furnace to
low redness, the oxidation of the materials will go on rapidly, so that the whole
mass will have been transformed into its original condition, namely, chromate

page_text: of lime, and be ready again to perform its part in the production of chlorine.
by the application of a fresh quantity of hydrochloric acid.
Having thus described the particulars of my Invention, and the manner in.
which the same may be carried into practice, I would have it distinctly
understood that I do not claim any particular arrangement or apparatus for
carrying out my Invention, for these may be varied without interfering with
the principle of the scheme; but what I do claim as my Invention is the use
of chromate of lime in the manufacture of chlorine in connection with the
mode of its recovery, as herein-before described.
In witness whereof, I, the said James Shanks, have hereunto set my
hand and seal, this Twenty-fourth day of February, in the year of
our Lord One thousand eight hundred and fifty-nine.
JAMES SHANKS. (L.S.)
Taken and acknowledged in Chancery by
the said James Shanks, before me,
EDWP. JOHNSON,
A Commissioner to Administer Oaths in Chancery in England.
Signed, sealed, and delivered by the said
James Shanks, in the presence of
ROBT. SLATER,
EDWP. JOHNSON, Sol., St. Helens.