IMPROVEMENTS IN THE MANUFACTURE OF NITRATE OF POTASH
Year: 1863

page_text: LETTERS PATENT to Joseph Townsend, of Glasgow, in the County of
Lanark, North Britain, Manufacturing Chemist, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF NITRATE OF POTASH."
Sealed the 3rd May 1864, and dated the 6th November 1863.
PROVISIONAL SPECIFICATION left by the said Joseph Townsend at the
Office of the Commissioners of Patents, with his Petition, on the 6th
November 1863.
I, JOSEPH TOWNSEND, of Glasgow, in the County of Lanark, North Britain,
Manufacturing Chemist, do hereby declare the nature of the said Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF NITRATE OF POTASH," to be as
follows, that is to say:-
This Invention relates to the manufacture of nitrate of potash in a simpler,
superior, and more economical manner than hitherto practised. To make the
nitrate of potash nitrate of soda is taken in conjunction with muriate of
potash, sulphate of potash, or carbonate of potash, as is usual, but instead of
adding thereto as much water as will dissolve the whole, or nearly the whole
of both salts employed, there is added a smaller quantity of water, such water
being hot. It is preferred to proportion the quantity of water so as to produce
a solution of a strength of about 102 degrees Twaddell, but a somewhat
greater or less strength will also answer. The solution being allowed to
stand, muriate, sulphate, or carbonate of soda is deposited, having above it
the nitrate of potash in a more or less impure condition. The nitrate of

page_text: potash partially crystallises, and whilst crystallising is, by preference stirred,
so as to granulate it, in order to facilitate its subsequent purification. The
mother liquor is evaporated until the remaining salts of soda contained in it
are deposited, and any further nitrate of potash thereby separated is crystalized
as before. The crystalized nitrate of potash is washed with cold water to
remove any muriate, sulphate, or carbonate of soda remaining with it, and for
this purpose it is preferred to put it into a vessel with a perforated false
bottom, the water either draining through it downwards, or being introduced
below, and rising up through it; the water used in this process is employed in
making fresh solutions of the raw materials, or it may be evaporated, so as to
yield further quantities of the nitrate of potash. The nitrate of potash after
being washed as described is dried, by preference by means of a hydro-
extractor, aided by hot air. The product thus obtained is of considerable
purity, but it may be further purified by well-known processes if desired.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Joseph Townsend in the Great Seal Patent Office on the
5th May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
TOWNSEND, of Glasgow, in the County of Lanark, North Britain, Manu-
facturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of November, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Joseph Townsend, Her special licence that I, the said
Joseph Townsend, my executors, administrators, and assigns, or such others
as I, the said Joseph Townsend, 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 "IM-
PROVEMENTS IN THE MANUFACTURE OF NITRATE OF POTASH," upon the con-
dition (amongst others) that I, the said Joseph Townsend, 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,

page_text: 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 Joseph Townsend, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement in writing, that is to say:-
My said Invention relates to the manufacture of nitrate of potash in a
simpler, superior, and more economical manner than hitherto practised. To
make the nitrate of potash, nitrate of soda is taken in conjunction with
muriate of potash, sulphate of potash, or carbonate of potash, as is usual, but
instead of adding thereto as much water as will dissolve the whole, or nearly
the whole of both salts employed, there is added a smaller quantity of water,
such water being hot. It is preferred to proportion the quantity of water so
as to produce a solution of a strength of about 102 degrees Twaddell, but
a somewhat greater or less strength will also answer. The solution, is by
preference, formed in a cylindrical vessel heated by a coil of steam piping,
which piping is arranged around and against the sides, and in the centre a
shaft fitted with beaters is made to revolve to keep the solution agitated,
and prevent deposits on the steam pipes. The solution being formed of the
proper strength is run into vessels fitted with filter beds, and is allowed to
stand sufficiently for the muriate, sulphate, or carbonate of soda to be
deposited. The solution of nitrate of potash is drained off through the
deposited soda salts, and is conducted to the crystalising vessels, where it
partially crystalises without being again heated, and whilst crystalising it is,
by preference stirred, so as to granulate it, in order to facilitate its subsequent
purification. The mother liquor is evaporated, by preference, in a vessel with
an agitator, and coil of steam piping arranged like the vessel herein-before
described as for forming the primary solution, and the evaporation is continued
until the liquor is sufficiently concentrated to deposit any remaining salts of
soda contained in it, such deposit being effected in filtering vessels as before,
whilst the remaining nitrate of potash is drawn off therefrom, and crystalised
as before. The crystalised nitrate of potash is washed or treated with cold
water to remove any muriate, sulphate, or carbonate of soda remaining with
it, and for this purpose it is put into a vessel with a perforated false bottom,
and the water is either made to drain slowly through it downwards, or is
introduced below, so as to rise up slowly through it. The water used in this
process is employed in making fresh solutions of the raw materials, or it may
be evaporated, so as to yield further quantities of the nitrate of potash. The

page_text: nitrate of potash after being washed as described is dried, by preference by
means of a hydro-extractor aided by hot air. The product thus obtained is
of considerable purity, but it may be further purified by well-known processes
if desired.
Having thus particularly described my said Invention, and the manner in
which the same is or may be performed, I have to state that I do not
restrict myself to the precise details herein-before described; but that what I
believe to be novel and original, and claim as the Invention secured to me.
by the herein-before in part recited Letters Patent, is, the separating, the
purifying, and the drying of nitrate of potash by improved means, substantially
such as are herein-before described.
In witness whereof, I, the said Joseph Townsend, have hereunto set
my hand and seal, this Fourth day of May, in the year of our Lord
One thousand eight hundred and sixty-four.
JOSEPH TOWNSEND. (L.S.)
Witness,
EDMUND HUNT,
Patent Agent,
28, St. Enoch Square, Glasgow.