IMPROVEMENTS IN THE MANUFACTURE OF SUPERPHOSPHATE OF LIMB
Year: 1855

page_text: LETTERS PATENT to Charles Frederick Burnard, of Plymouth, Manufac-
turing Chemist, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF SUPERPHOSPHATE OF LIMB."
Sealed the 3rd July 1855, and dated the 25th January 1855.
PROVISIONAL SPECIFICATION left by the said Charles Frederick Burnard
at the Office of the Commissioners of Patents, with his Petition, on the
25th January 1855.
I, CHARLES FREDERICK BURNARD, of Plymouth, Manufacturing Chemist, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF SUPERPHOSPHATE OF LIME" to be as follows:--
The object of this Invention is to manufacture for the purpose of manures
highly concentratedsuperphosphates, by increasingthepercentageofphosphoric
acid, either as free phosphoric acid, or in combination with other substances.
My mode of operating is as follows:-I take superphosphate of lime or other
soluble phosphate, and dissolve out the biphosphate with water, and dry down
in a reverberatory or other furnace, thus producing a very rich manure, con
taining a large per-centage of biphosphate, or an equivalent of phosphoric
acid; or I take the solution of biphosphate, or its equivalent of phosphoric acid,
and combine it with other portions of superphosphate of lime, and then dry
down in a reverberatory or other furnace, and by this means I produce a highly
soluble manure.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Frederick Burnard in the Great Seal Patent Office
on the 25th July 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
FREDERICK BURNARD, of Plymouth, Manufacturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of January, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give, and grant unto me,
the said Charles Frederick Burnard, Her special license that I, the said
Charles Frederick Burnard, my executors, administrators, and assigns, or such
others as I, the said Charles Frederick Burnard, 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 SUPERPHOSPHATE OF LIME," upon the
condition (amongst others) that I, the said Charles Frederick Burnard, by an
instrument in writing under my hand and seal, 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 nextand immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Charles Frederick Burnard, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertainedin and by the
following statement (that is to say):-
It is well known that in the manufacture of superphosphate of lime, as
hitherto conducted, various ingredients having a drying tendency, such as
gypsum, dry earth, or charcoal, are mixed or incorporated with the super-
phosphate, for the purpose of drying up the water or moisture contained in
themass, and thereby render the so-called superphosphate dry and pulverulent,
so that it may be brought into the market in a fit state to be used as manure
in agricultural operations. It is also a well-known fact that hitherto no
superphosphate of lime has been made for general use as a manure containing
more than eighteen per cent. of biphosphate of lime, which is the principal
fertilizing agent contained in the superphosphate. This small per-centage of
the soluble biphosphate in the ordinary superphosphate of lime arises from

page_text: the necessity of mixing the drying materials as aforesaid with the chemical
ingredients, in order to dry the latter, and form a marketable article as a
-manure.
The object of my present improvements is to obtain practically and com-
mercially for general public use a superphosphate of lime containing twenty
per cent. and upward of biphosphate, or, in other words, producing a marketable
article as superphosphate of lime, which will contain a higher per-centage of
the fertilizing agent than manure manufacturers have hitherto been able to
obtain practically.
In order to effect this object, I take calcined bone or animal charcoal, pre-
ferring such as contains a high per-centage of bone earth, (say, from seventy to
eighty per cent.) After grinding this substance very fiue I take any con-
venient quantity, say, ten hundredweight, and mix therewith water until the
latter begins to flow from the heap. The mass of ground bones or animal
charcoal and water is then submitted to the action of heat in a furnace, (I
prefer an ordinary reverberatoryfurnace, as being the most convenient mode of
applying heat to the mixture,) and I add to the mass a sufficient quantity
of oil of vitriol, brown sulphuric acid, or acid of any specific gravity, which may
be let down on the goods, taking care to keep the whole mass well stirred and
turned under the action of the fire, in order to cause the acid to be well incor-
porated with, and properly to act upon, the calcined bones or animal charcoal.
In a short time, if the process be properly conducted, the mass may be drawn
out in a fine, dry, and pulverized condition. The quantity of acid required will
of course depend upon the quantity of neutralizing bases in the matter operated
on, and must be determined by analysis, and the supply of acid regulated
accordingly. By this means I am enabled to obtain superphosphate of lime
containing from twenty to twenty-seven per cent. of biphosphate of lime, being
a considerably richer superphosphate than that usually manufactured.
In order to produce a still richer superphosphate, I take any superphosphate
of limeorphosphatesolubleinwater, (preferring, however, superphosphatemade
according to the process herein-before described,) and byanyconvenient method
I wash or dissolve out the biphosphate of lime or soluble phosphate therefrom,
and the solution thus obtained I mix with a fresh quantity of calcined bone
or animal charcoal, instead of using water, as herein-before described. The
mixture is then operated upon in the reverberatory furnace with oil of vitriol,
in the manner already described, and I am thus enabled to obtain a manure
containing from twenty-five to thirty per cent. of biphosphate of lime (or of
phosphoric acid free or combined equal to that quantity of biphosphate of lime).
When I propose to dissolve out the soluble biphosphate from the super-

page_text: phosphate made according to the process first described, I find it convenient
in making the superphosphate to employ an excess of acid, so that the calcined
bones or animal charcoal may be more certainly acted upon. No loss or
inconvenience will result from thus using an excess of acid (if the super-
phosphate produced is submitted to the washing process a above mentioned), as
not only the biphosphate, but all the uncombined acid and other soluble
matters, will be washed out and used at a subsequent time in operating upon a
fresh supply of calcined bones or animal charcoal, as above explained. By this
means there is a great economy of acid, for all the free acid in the super-
phosphate produced by the first operation is rendered available in the second,
thus lessening the quantity used in the second operation.
Instead of employing the soluble phosphates (that have been extracted from
the superphosphate, as above explained), for admixture with a fresh quantity
of calcined bones, I sometimes propose to take the soluble phosphate when
dissolved out, as aforesaid, and concentrate or evaporate the solution in pans or
furnaces, and thereby obtain a dry manure in a granular form, and containing
a very high per-centage of phosphoric acid free or combined, or both. If
thought desirable, I add to the concentrated solution, while in the said pans or
furnaces, potash, soda, ammonia, or their carbonates, or substances capable of
yielding ammonia, for the purpose of combining with the phosphoric acid for
making a manure.
Having now described my Invention of "Improvements in the Manufacture
of Superphosphate of Lime," and the means of carrying the same into effect,
I would observe that I am aware that superphosphate of lime has been hereto-
fore produced by submitting calcined bones or animal charcoal in combination
with other materials to the action of sulphuric acid; and further, that calcined
bones or animal charcoal alone have been submitted to the action of sulphuric
acid, and other materials, such as gypsum ordrying earth, have been subsequently
added to the dissolved bones and acid, in order to produce a dry compost that
would be suitable for agricultural purposes; I do not therefore mean or intend
to claim such processes as of my Invention. I wish it also to be understood
that although, in the process herein-before set forth, I have stated that the heat
which I propose to employ in carrying out my improvements is applied to
the goods in a reverberatory furnace where the materials are submitted to the
direct action of the flame of a fire, yet I do not intend to confine myself to this
mode of applying the heat, which is not only employed for the purpose of
driving off the aqueous portions of the ingredients, and to reduce the mass to
a moderately dry state, but also materially facilitates the process of converting
the ingredients into superphosphate. In conclusion, I would observe that the

page_text: points which I consider to be new in the process or processes herein-before
described, and therefore wish to claim as the Invention secured to me by
Letters Patent as aforesaid, are,
First, the manufacture of dry superphosphate of limo suitable for agricul-
tural use as manure by submitting calcined bones or animal charcoal to the
action of sulphuric or other acid in the presence of artificial heat, either in a
reverberatory or other furnace, or otherwise, whereby I am enabled to produce
a dry pulverulent mass without the necessity of employing drying carths, and
I also obtain a highly concentrated superphosphate containing a greater per-
centage than usual of the soluble phosphate or fertilizing agent.
Second, Iclaim dissolving out of superphosphate of lime(either obtained by
the process above described or otherwise) the soluble biphosphate and other
soluble parts,and also the uncombined acid contained therein, and employing
the solution so obtained in place of common water in the process of making
further quantities of superphosphate, so that a greater quantity of soluble
biphosphate may be obtained in a given quantity of superphosphate than if
simple water be employed to wet the calcined bones or animal charcoal, as in
the process first described.
I also claim, dissolving out from superphosphate of lime the soluble
biphosphate and other soluble parts contained therein, which solution, either
with or without the addition of alkalies or their salts, may be concentrated or
evaporated by means of heat applied in any convenient manner, so as to
produce a granular mass of high fertilizing power, and which may be employed
as a manure.
In witness whereof, I, the said Charles Frederick Burnard, have hereunto
set my hand and seal, the Seventeenth day of July, in the year of
our Lord One thousand eight hundred and fifty-five.
Witness,
JOHN ALGER,
CHARLES FREDERICK BURNARD. (LS.)
Briton Side, Plymouth.