IMPROVED SUPERPHOSPHATE OF LIME
Year: 1859

page_text: LETTERS PATENT to John Dyer Bryant, of Rock, in the County of
Cornwall, Merchant, for the Invention of "IMPROVED SUPERPHOSPHATE
OF LIME."
Sealed the 7th October 1859, and dated the 9th August 1859.
PROVISIONAL SPECIFICATION left by the said John Dyer Bryaut at
the Office of the Commissioners of Patents, with his Petition, on the
9th August 1859.
I, JOHN DYER BRYANT, of Rock, in the County of Cornwall, Merchant, do
hereby declare the nature of the said Invention for "IMPROVED SUPERPHOSPHATE.
OF LIME," to be as follows :-
The improvement consists in getting rid of the carbonate of lime usually
found in combination with the raw materials from which the said superphosphate
of lime is manufactured. Under the head of raw materials I include all such
substances, not being animal matter, charged with oil or grease, as either, with
or without admixture of other matter, contain carbonate of lime and phosphate:
of lime in combination.
The said improvement may be carried into effect by either of the two
following processes :-I either take the raw materials, crush them into pieces
of a convenient size, after which I expose them to such a degree of heat, as to
expel the carbonic acid from the carbonate of lime, and convert the said car-
bonate of lime into pure lime. I next place the said materials in a grinding
mill, and grind them to a state of extreme fineness. The said materials are
then exposed to the action of a stream of pure water, or water impregnated.

page_text: with bittern, muriatic acid, or some similar substance when a large proportion
on of the lime combines with the said water, and is thus removed.
The second mode which I adopt consists in first grinding the said materials
to a state of extreme fineness, and then subjecting the same to the degree of
heat above mentioned. It is essential at this stage of the process, and previous
to the operation of washing next herein-after described, that the said materials
should be kept dry, and exposed as little as possible to the action of the
atmosphere. The said materials are then exposed to the action of water, and
the carbonate of lime removed as herein-before described. By drying the
residuum obtained by either of the methods herein-before described, and
repeating the said operations of heating and washing, a further quantity of the
said lime may be discharged from the said materials. The remainder of the
said manufacture of the said superphosphate is conducted in the ordinary mode.
by subjecting the said materials from which the said carbonate of lime has
been wholly or partially removed to the action of sulphuric acid.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Dyer Bryant in the Great Seal Patent Office on the
9th February 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
DYER BRYANT, of Rock, in the County of Cornwall, Merchant, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of August, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Dyer Bryant, Her special licence that I, the said John Dyer
Bryant, my executors, administrators, and assigns, or such others as I, the said
John Dyer Bryant, 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 "IMPROVED SUPERPHOSPHATE OF LIME," upon the condition (amongst others)
that I, the said John Dyer Bryant, 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

page_text: 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 John Dyer Bryant, do hereby declare
the nature of the 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 thereof, that is to say :-
The improvement consists in getting rid of the carbonate of lime usually
found in combination with the raw materials from which the said super-
phosphate of lime is manufactured. Under the head of raw materials, I.
include all such substances, not being animal matter, charged with oil or.
grease, as either, with or without admixture of other matter, contain carbonate.
of lime and phosphate of lime in combination or admixture. The said
improvement may be carried into effect by either of the two following
processes: I either take the raw materials and crush them into pieces of a
convenient size, after which I expose them to such a degree of heat as to
expel the carbonic acid from the carbonate of lime, and convert the said
carbonate of lime into pure lime. I next place the said materials in a grinding.
mill and grind them to a state of extreme fineness. The said materials are
then exposed to the action of a stream of pure water, or water impregnated
with bittern or some similar substance, when a large proportion of the lime
combines or mixes with the said water, and is thus removed.
The second mode which I adopt consists in, first, grinding the said materials
to a state of extreme fineness, and then subjecting the same to the degree of
heat above mentioned. It is essential at this stage of the. process, and
previous to the operation of washing, next herein-after described, that the said
materials should be kept dry, and exposed as little as possible to the action of
the atmosphere. The said materials are then exposed to the action of water.
and the lime removed, as herein-before described. By drying the residuum
obtained by either of the methods herein-before described, and repeating the
said operations of heating and washing, a further quantity of the said lime
may be discharged from the said materials. The remainder of the said
manufacture of the said superphosphate is conducted in the ordinary mode by.
subjecting the said materials from which the said carbonate of lime has been
wholly or partially removed to the action of sulphuric acid. But that the
nature of my said Invention may be more fully understood I will proceed to
describe the same more in detail.
Superphosphate of lime is usually obtained by treating raw materials
containing phosphate of lime with sulphuric acid, so as to decompose a portion
of the said phosphate of lime by sulphuric acid, by which means a portion of

page_text: phosphoric acid is liberated and attaches itself to the remaining phosphate of
lime which then has a super quantity of phosphoric acid and becomes a super-
phosphate. And as the raw material.cóntaining phosphate of lime is found in
large quantities in combination or admixture with carbonate of lime and other
matters, and the presence of the carbonate of lime in the raw material is a
disadvantage, by reason of its requiring very nearly an equivalent quantity of
sulphuric acid to decompose it, for carbonic acid having less affinity for lime
than phosphoric acid, the carbonate of lime will be acted on by the sulphuric'
acid before the phosphate of lime is acted on by it. Chemically speaking,
50 parts of carbonate of lime require 49 parts of concentrated sulphuric acid,
commonly called white oil of vitriol, of a specific gravity of 1-848 to decompose
it, and when the said carbonate of lime is decomposed by sulphuric acid, the
lime in it combines with the sulphuric acid, and it then remains in the state
of sulphate of lime, otherwise gypsum, otherwise plaster of Paris, and is in
that state a hindrance to the manufacture of superphosphate of lime from the
phosphate of lime, with which it was found in connection, especially by coating
over the particles of raw material with plaster of Paris, and preventing the
sulphuric acid from attacking the phosphate of lime and decomposing it; and
such sulphate of lime or gypsum, whatever may be its value as a manure,
costs very much more to get it by this process than the usual market price for
gypsum found in its natural state. It is desirable to get rid as much as
possible of the carbonate of lime before the phosphate of lime in the raw
material, with which it is found in combination, is subjected to the action of
sulphuric acid. Now the manner in which I propose to get rid of the said
carbonate of lime, or a portion of it, is as follows:-I subject the raw material
to the action of heat sufficient to expel from it the carbonic acid which the
carbonate of lime contains, and the carbonate of lime, after the expulsion of
carbonic acid is reduced to the state of caustic lime, and becomes soluble in
the solvents which are herein-after named.
Reverberatory furnaces may be used to apply heat to the raw material,
which may be placed in the furnace either in lumps of a convenient size, or
reduced to the state of a very fine powder. Care must be used in the
application of heat, so that sufficient heat only be employed to repel the
carbonic acid found in the raw material. If the raw material is placed in
the furnace in a state of powder, I have found it desirable to stir or turn it
over two or three times an hour, in order to expose it equally to the action of
the heat and facilitate the liberation of the carbonic acid. The particles of
the powder should be of as equal a size, as possible.
Some descriptions of raw material contain silica of a description which has

page_text: a tendency to vitrify or unite with the lime in a great heat. This 'vitrification
of silica, or combination thereof with lime, whole or partial, it is desirable to
avoid, as in that state. it will be less soluble by the herein-after named solvents.
As soon as the carbonic acid has been to a great extent expelled, I withdraw
the raw material from the furnace through doorways or other suitable openings
After
for the purpose in the sides or other convenient part of the furnace.
the raw material has been withdrawn from the furnace I exclude it as much
as possible from contact with the atmosphere to prevent its absorbing fresh
carbonic acid therefrom, and supposing it to have been placed in the furnace
in lumps,. I should now reduce it by grinding to a very fine powder. It will;
however, generally be found most advantageous to reduce the raw material to
the state of a powder before subjecting it to the action of heat. After the
carbonic acid has been expelled, and the raw material reduced to a minute state
of subdivision, as before described, the lime remaining from the carbonate of
lime may be dissolved in, or treated with, either of the following solvents or
liquids, viz.,-1, rain, river, or spring water; 2, water mixed with acids, or
combined with alkaline or magnesian salts from chemical manufactories or
other sources; .8, water mixed with bittern, or the refuse of sea salt manu-
factories; 4, sea water in its natural state, and this latter will generally be
found the most economical solvent for the purpose. The raw material will be
mixed with either of the aforesaid solvents in quantity sufficient to dissolve
the lime it contains, and when mixed agitated so as to bring the particles of
raw material as much as possible in contact with the solvent liquid. The
quantity of solvent required will of course depend on the quantity of lime in
the raw material, or of acid in the solvent, which a little experience of a
person acquainted with like operations in practical chemistry will readily
determine. The raw material may be thrown into a stream of one of the
solvents when running from one reservoir to another, or may be put into a
reservoir containing a solvent, in which a vertical axle with horizontal arms
may be made to revolve and cause the requisite agitation, or any other equi-
valent mode of mixing and agitating may be used. After the materials have
been well mixed in the solvent or liquid, the phosphate of lime may be
allowed to subside to the bottom of the reservoir, in order to the solvent or
liquid and any particle of lime held therein being withdrawn from the deposit.
Bittern and sea water contain sulphate and muriate of magnesia, and in case
bittern or sea water, or water combined with magnesian salts, is used, lime
combines with the acids in the liquid employed, and precipitates magnesia,
which is a very floculent precipitate, and the mixing or other action should be
gradually decreased so as to retain the magnesia in suspension, and when the

page_text: water or solvent is drawn off the magnesia goes with it. After the operations
of burning and washing have been performed one or more times, as before
described, any carbonate of lime remaining will be in the interior of the
particles of raw material, and less detrimental in that position than if diffused
throughout, as the exterior of the particles would be decomposed by the
sulphuric acid before the carbonate would be reached; but by repeating the
processes, a much higher state of purification may be obtained. After
carbonate of lime has been got rid of, in the manner before described, the
remainder of the said manufacture of superphosphate of lime is carried on by
treating the raw material thus treated with sulphuric acid in the usual way.
Having thus described my Invention, and the best means I am acquainted
with for carrying the same into effect, I would have it understood that what I
claim is the adaptation or combination of means or processes for the production
of superphosphate of lime, substantially as herein explained.
1
In witness whereof, I, the said John Dyer Bryant, have hereunto set. 1
my hand and seal, this Ninth day of February, in the year of our
Lord One thousand eight hundred and sixty.
Witness,
WILLIAM BROOKES,
73, Chancery Lane, London,
Patent Agent.
J. D. BRYANT. (L.S.)