IMPROVEMENTS IN THE MANUFACTURE OF SALTS AND PREPARATIONS OF PHOSPHORIC ACID
Year: 1857

page_text: LETTERS PATENT to Thomas Richardson, of Newcastle-upon-Tyne, and
Manning Prentice, of Stowmarket, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF SALTS AND PREPARATIONS OF PHOSPHORIC ACID."
>
PROVISIONAL SPECIFICATION left by the said Thomas Richardson and
Manning Prentice, at the Office of the Commissioners of Patents, with
their Petition, on the 15th October 1857.
We, THOMAS RICHARDSON, of Newcastle-upon-Tyne, and MANNING PRENTICE,
of Stowmarket, do hereby declare the nature of the Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF SALTS AND PREPARATIONS OF PHOSPHORIC ACID," to
be as follows:-*
This Invention has for its object the separation of carbonates of lime and
magnesia from coprolites and other substances containing phosphate of lime.
For this purpose the substance to be treated is calcined so as to render caustic
the lime and magnesia, which are then removed by treating the calcined
matter with water.
The Invention also consists in an improved method of preparing super-
phosphate of lime or other preparations of phosphoric acid for use as a
manure from coprolites or other substances containing phosphate of lime,
and which have by preference been previously prepared in the way above

page_text: described. For this purpose we.add to the substance to be treated a sufficient
quantity of sulphuric acid to liberate all the phosphoric acid and we allow
the mixture to subside until. all, the sulphate of lime. formed is deposited; we
then decant off the clear fluid and add a portion of the original coprolite or
other substance containing phosphate of lime, and evaporate the mixture to
dryness or to other desired extent, so as to obtain superphosphate of lime or
other compound-of-lime and phosphoric acid; the addition of the coprolite or
other substance having been made to the phosphoric acid solution just in the
proportion necessary to form the required substance. Or, the solution of
phosphoric acid may be evaporated nearly to dryness and then dried up
by adding muriate or sulphate of soda or potash to
phate of those bases is obtained. Or, the soda or
added before the evaporation is commenced, but the former is the pre-
ferable process. Or, the phosphoric acid solution may in the same way be
treated with magnesia, or some of its salts, or it may be neutralized with
ammonia.
it, by which a phos-
potash salt may be
Sometimes in place of, or in addition to, the substances above named, we
employ sawdust, cobb or cosh malt chives, and other similar substances, for
drying up the phosphoric acid solution, and the material obtained in this way
is suitable for use for purifying gas, and also as a manure. This process of
treating coprolites or other substances containing phosphate of lime may be
varied by adding only a sufficient quantity of sulphuric acid to produce a
superphosphate of lime, and then, after the sulphate of lime has been deposited,
evaporating the clear solution of superphosphate to dryness, or other desired
extent, and drying up by sawdust or other similar drier.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Richardson and Manning Prentice in the Great Seal
Patent Office on the 15th April 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, THOMAS
RICHARDSON, of. Newcastle-upon-Tyne, and MANNING PRENTICE, of Stow-
market, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of October, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors; give and grant unto us, the
said Thomas Richardson and Manning Prentice, Her special licence that we,

page_text: the said Thomas Richardson and Manning Prentice, our executors, 'adminis-
trators, and assigns, or such others as we, the said Thomas Richardson and
Manning Prentice, our 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 SALTS AND PREPARATIONS OF PHOSPHORIC ACID," upon the
condition (amongst others) that we, the said Thomas Richardson and Manning
Prentice, our executors or administrators, by an instrument in writing under
our or their hands and seals, or under the hand and seal of one of us or
them, 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 Manning Prentice, on behalf of myself
and the said Thomas Richardson, do hereby declare the nature of the said
Invention, and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement thereof,
that is to say:-
This Invention has for its object the separation of carbonates of lime and
magnesia from coprolites and other substances containing phosphate of lime.
For this purpose the substance to be treated is calcined, so as to render
caustic the lime and magnesia, which are then removed by treating the
calcined matter with water. In putting into operation this part of our Inven-
tion we take coprolite or any other phosphatic material containing carbonate
of lime or magnesia, or both, and submit them to a strong red or white heat
in any convenient furnace, and we prefer to employ a reverberatory furnace,
such as is shewn in the annexed Drawing. The construction is of the
ordinary description, the furnace having two beds a and b, the latter being
covered with the fresh charge which is being heated up by the surplus heat
whilst the charge nearest the fire bridge is being worked off. The charge
for each flat weighs about 10 cwt., and we agitate the mass during the
calcination to economise fuel and facilitate the escape of the carbonic acid.
When an average sample drawn from the first bed of the furnace and
moistened with water, ceases to effervesce on the addition of a strong acid,
the calcination is complete, and the charge may be removed. The charge on
the second bed of the furnace is now pushed forward and its place supplied
with another lot of the raw material. The calcined material is now,ground

page_text: under edge stones or otherwise to as fine a powder as possible, and thrown
into pits or cisterns and covered with water to the depth of two or three feet;
this water may be spring or rain-water, it ought not to be too hard nor
contain any considerable quantity of carbonate of lime in solution in carbonic
acid, but we prefer to employ sea-water or water containing common salt or
a little muriatic acid, which promotes the solution of the lime: The calcined
materials are agitated from time to time, and then allowed to subside." The
clear supernatant liquid is then syphoned or drawn off, and it should never be
allowed to stand too long, as it will become covered with a crust of carbonate of
lime, which requires care in removing to-prevent its mixing with the undissolved
materials. The liquid syphoned or drawn off is immediately replaced by a
fresh portion of water, and this operation is repeated until no more lime is
dissolved, which is easily recognised by the absence of the peculiar taste of
lime water or by any of the ordinary chemical tests for lime.
This calcined
and washed material may be employed for the manufacture of superphosphate
of lime or other preparation of phosphoric acid as will be presently explained,
or it may be dried in the air or any suitable furnace and substituted for most
of the purposes for which pure bone ashes are now employed.
The invention also consists in an improved method of preparing super-
phosphate of lime, or other preparations of phosphoric acid, for use as a
manure from coprolites or other substances containing phosphate of lime, and
which have by preference been previously prepared in the way above described.
For this purpose we add to the substance to be treated a sufficient quantity of
sulphuric acid to liberate all the phosphoric acid, and we allow the mixture to
subside until all the sulphate of lime formed is deposited; we then decant off
the clear fluid, and add a portion of the prepared coprolite or other substance
containing phosphate of lime, and evaporate the mixture to dryness or to other
desired extent, so as to obtain superphosphate of lime or other compound of
lime and phosphoric acid, the addition of the coprolite or other substance
having been made to the phosphoric acid solution just in the proportion
necessary to form the required substance. In putting into operation this part
of our Invention, we first ascertain the per-centage of phosphates and car-
bonates of the earth bases in the coprolites, or other substances containing
phosphate of lime which are to be treated, and which may either be in the
crude state or prepared in the manner already described, and having thrown a
given weight of the substance into some convenient cistern or vessel, we
decompose the phosphates and carbonates (if any) by means of sulphuric acid,
adding 8 parts of real sulphuric acid for each part of carbonate lime, and
from 72 parts of real sulphuric acid for each part of bone earth, and we prefer

page_text: to employ weak acid for this purpose, say, at a strength about 109 specific
gravity. The materials may be heated by admitting steam or otherwise, and
kept in agitation at the same time to promote the necessary chemical:action:
When the decomposition is complete, which is known by ascertaining whether
any insoluble phosphate remains in the solid portion by any of the usual
chemical tests, the whole is allowed to subside, and the liquid portion is drawn
off from the sulphate of lime, sand, &c. These residual matters are washed
once or twice with water to remove the adhering phosphoric acid or soluble
phosphate of lime. Next we ascertain how much phosphoric acid is in the
solution, and we then. mix with it as much bone earth, in the form of our
calcined and washed material already described, as the phosphoric acid will
render soluble, or for every 72 parts of free phosphoric acid or thereabouts we
add as much as 78 parts of bone earth; we then evaporate this solution
to dryness, or to the consistence of a paste, either with bottom or surface
heat, and we prefer to add one or more of the driers known to manu-
facturers of manure (such as sawdust, cob or cosh, or malt, chives), in place
of adding bone earth as above described. The solution of phosphoric acid
may be evaporated nearly to dryness, and then dried up by adding muriate
or sulphate of soda or potash to it, by which a phosphate of those bases is
obtained or the soda or potash salt may be added before the evaporation is
commenced, but the former is the preferable process. The operation of the
acid solution, not previously evaporated, is conducted in the following
manner-Having ascertained, as before, the quantity of phosphoric acid in
our aqueous solution, we run a given quantity of the liquid into an ordinary
alkali decomposing furnace, or any other suitable apparatus, when we mix
it with either muriate or sulphate of the alkaline bases, potash or soda, in
such a proportion that the potash or sodá may just be in sufficient quantity
to combine with all the phosphoric acid present, and we apply heat and
agitation until the decomposition of these salts has been accomplished, after-
wards we dry the whole mass in the same way as is at present practised
with ordinary sulphate of soda, or we evaporate the aqueous solution of
phosphoric acid nearly to dryness, and complete the drying by the addition of
the above-named salts. In each case we prefer to employ, in addition to these
alkaline salts, one or more of the driers usually employed for drying up liquids
for manure and other purposes (such as sawdust, cob or cosh, or malt shives),
or we add to the above described aqueous solution of phosphoric acid 40 parts
of magnesia, by preference, in solution in water, or 42 parts of carbonate
magnesia for every 72 parts of phosphoric acid, and evaporate the resulting
phosphates of magnesia to dryness in the usual way; or we evaporate the

page_text: "
aqueous solution of phosphoric acid nearly to dryness, and complete the drying
up by means of sawdust, cob or cosh, malt chives, or other similar materials,
which material may be used as manure in the place of ordinary superphosphate
of lime, or the phosphoric acid, it contains may be neutralized by, ammonia, by
exposing it on perforated trays or shelves in the purifiers, ordinarily at work in
gas
works or otherwise, and afterwards used as a manure. This process of
treating coprolites or other substances, containing phosphate of lime may be
varied by adding only a sufficient quantity of sulphuric acid, to produce a
superphosphate of lime, and then after the sulphate of lime has been deposited,
evaporating the clear solution of superphosphate to dryness or other desired
extent, and drying up by sawdust or other similar drier. In conducting the
process in this manner, we add to the coprolites or other substances containing
phosphate of lime for each part of bone earth, 52 parts of real sulphuric acid,
and proceeding as before, we obtain a solution of mono-phosphate of lime, which
we decant from off, the insoluble matter, and evaporate to dryness .or.the
consistence of a, paste, which we then dry up with sawdust.or other similar
material.
In each of the operations above described for the production of a soluble
phosphate for use as a manure, we prefer, as already stated, to employ an
organic drier, such as; sawdust, and the proportion in which these artificial
driers may be advantageously used are various, when the object is to obtain a
manure as rich in soluble phosphate as possible, the evaporation is carried
nearly to dryness, and only as much sawdust, for example, is added as will
produce a coarse powder capable of being riddled, but in other cases. the weight
of drier added may equal the weight of the soluble phosphate with advantage.
In witness whereof, I, the said Manning Prentice, have hereunto set my
hand and seal, this Thirteenth day. of April, in, the year of our Lord
One thousand eight hundred and fifty-eight:
Witness,
JOHN ALCOCK.
MANNING PRENTICE. (L.S.)