A NEW MANUFACTURE OF SOLID NONDELIQUESCENT PHOSPHATE OF, LIME SOLUBLE IN WATER
Year: 1883

page_text: LETTERS PATENT to Charles Denton Abel of N° 28 Southampton Buildings
Chancery Lane in the County of Middlesex for an Invention of "A NEW
MANUFACTURE OF SOLID NONDELIQUESCENT PHOSPHATE OF, LIME SOLUBLE IN
WATER communicated to him from Abroad by François Barbe of Paris in the
French Republic
"
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 4th December 1883.
CHARLES DENTON ABEL of N° 28 Southampton Buildings, Chancery Lane in
the County of Middlesex A NEW MANUFACTURE OF SOLID NONDELIQUESCENT
PHOSPHATE OF LIME SOLUBLE IN WATER [communicated to him from Abroad by
François Barbe of Paris in the French Republic]
"
It is well known that the artificial manure known as superphosphate of lime is
prepared by treating natural phosphates when reduced to powder, with sulphuric
acid.
The composition of this body is very complex, and has not yet been determined
with exactness by chemists.
It is however known that superphosphate of lime contains two different
elements: 1st. A part soluble in water which is formed by phosphoric acid Ph 05
3 HO, and by acid phosphate of lime Ph 05, Ca O, 2, HO; second, a large pro-
portion, insoluble in water, amounting frequently to from 60 to 80 per cent. of the
product, formed of sulphate of lime, natural phosphate not acted upon, silicious or
calcareous gangue, phosphate of iron, phosphate of alumina, bibasic and crystalline
phosphate of lime, soluble in citrate of ammonia, and phosphate that has been
deprived of its solubility by the citrate of ammonia.
Among all the bodies contained in the superphosphate of lime, only two are
utilised in agriculture, namely the bibasic phosphate of lime which is soluble in
citrate of ammonia, and the phosphate of lime soluble in water.
The analytical determination of these two bodies presents difficulties well known to
chemists, and which give rise to uncertainty and even frauds which frequently deter
Price 1

page_text: agriculturists from using such chemical manures. Chemical manures will only be
accepted with confidence by agriculturists when the very complex compounds now
offered to them are replaced by well defined products, the purity of which could
easily be ascertained by the consumer.
The present invention has for its object the attainment of this end and relates
to a new manufacture of phosphate of lime soluble in water. When sulphuric acid
is mixed with natural phosphate of lime, the product solidifies, forming one part
which is soluble in water, the nature of which is however unknown; this substance
is not deliquescent whereas phosphoric acid and acid phosphate of lime absorb
rapidly atmospheric moisture, as is well known; the solidity of the superphosphate
is therefore not due to these two bodies. After long researches, my correspondent
has found that the phosphate of lime soluble in water and not deliquescent existing
in the superphosphates is a new salt which, by its composition, is situated between
the acid phosphate of lime PH O' Ca O, 2 HO, and bibasic phosphate of lime PHO
2 Ca OHO, and having discovered this scientific fact, he has invented a method
enabling this new salt to be prepared industrially. For this purpose, it was found
sufficient either to add a suitable proportion of phosphoric acid to insoluble basic
phosphates of lime, or to remove a certain quantity of lime from insoluble
phosphates, or to add to phosphoric acid the exact proportion of lime which will
produce the new solid phosphate, which is non deliquescent and entirely soluble
in water. The desired result was arrived at by practically carrying out the
different processes which I will now describe.
When it is desired to produce the new phosphate in starting with the natural
phosphate PHO³ 3 Ca O, this salt is treated with a sufficient quantity of sulphuric
acid to remove the proportion of lime which made it insoluble; the product is
washed and gives a liquor which is evaporated to dryness. For obtaining the new
salt in a pure state, that is to say, soluble in water without leaving a residue, the
phosphoric acid is first prepared by the ordinary method, which consists in
decomposing the natural phosphate of lime by means of sulphuric acid; the product
of this reaction, which liberates the phosphoric acid, is submitted to lixiviation and
the liquor is concentrated to a syrupy consistency. The phosphoric acid thus
obtained is mixed with the quantity of lime necessary for producing the
intermediate phosphate, that is to say, the salt situated between the acid
phosphate Ph 0³, Ca O, 2 HO, and the bibasic phosphate Ph 05 2 Ca O, HO. This
salt is formed by treating phosphoric acid either with hydrated lime or with
carbonate of lime, or with natural phosphate of lime or with precipitated phosphate
of lime Ph 05 3 Ca O, or with crystalline bibasic phosphate Ph 05 2 Ca O, HO. In
this reaction of the calcareous compounds upon the phosphoric acid, the product is
generally formed in mass and becomes rapidly very hard; this combination of
phosphoric acid with lime explains the solidification of the superphosphates in the
ordinary manufacture. The phosphate of lime thus obtained is of a white color,
nondeliquescent and perfectly soluble in water; it affords to agriculture a very
intense agent of absolute purity, and the energy of which can be modified at will
by mixing it with sand, earth, or other inert bodies.
The use of this body also offers an advantage that will be generally appreciated,
namely, that as it does not contain useless substances, such as are present in such
large quantities in the ordinary superphosphates, the cost of transport thereof will
be comparatively small, thus rendering it particularly available for exportation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Denton Abel in the Patent Office on the 3rd May 1884.
CHARLES DENTON ABEL of N° 28 Southampton Buildings, Chancery Lane, in
the county of Middlesex "A NEW MANUFACTURE OF SOLID NON-DELIQUESCENT
PHOSPHATE OF LIME, SOLUBLE IN WATER A communication to me from abroad
"
by François Barbe of Paris in the French republic.
It is well known that the artificial manure known as superphosphate of lime is
prepared by treating natural phosphates, when reduced to powder, with sulphuric
acid. This superphosphate of lime contains two different elements:
A part soluble in water and a large proportion, insoluble in water, amounting
frequently to from 60 to 80 per cent. of the product, formed of sulphate of lime,
natural phosphate not acted upon, silicious or calcareous gangue, phosphate of iron,
phosphate of alumina, and bibasic phosphate of lime, soluble in citrate of ammonia ;
also phosphate that has lost its solubility in the citrate of ammonia.
Among all the bodies contained in superphosphate of lime, only two are utilised
in agriculture, namely, the phosphate of lime soluble in water and the bibasic
phosphate of lime which is soluble in citrate of ammonia, but not in water.
The analytical determination of these two bodies presents difficulties which are
well known to chemists and which give rise to uncertainty and even frauds which
frequently deter agriculturists from using such chemical manures. Chemical
manures will only be accepted with confidence by agriculturists when the very
complex compounds now offered to them are replaced by well defined products, the
purity of which could easily be ascertained by the consumers.
The present invention has for its object the attainment of this end, by the,
production of a solid substance, not deliquescent, soluble in water, very rich in
phosphoric acid, of uniform chemical composition and not capable of acting on the ;
bags in which it is packed. These are the qualities possessed by the substance
manufactured according to this invention, which is termed "solidified phosphoric
acid," or triple phosphate of lime, and which is produced by the solidification of
phosphoric acid. by means of a small quantity of lime. Various calcareous;
substances can be used for solidifying the phosphoric acid, but a hydrate or a
carbonate of lime is preferred, because these insure the synthetic production of a
substance of uniform composition. A pure precipitate of phosphate of lime may
also be used. The solid phosphoric acid or triple phosphate of lime is produced
when the phosphoric acid is added to the lime in suitable proportions.
The following is the most simple manner of operating. 100 parts of sirupy
phosphoric acid, containing from 48 to 50 per cent of anhydrous phosphoric acid
(Ph 05) become immediately solidified by the addition of from 20 to 23 parts of
bydrate of lime. The substance thus obtained contains, after air drying, from
48 to 50 parts of phosphoric acid (Ph 0), that is to say, the same quantity of acid
as was contained in the sirupy liquor used, and it may therefore well be termed
solid phosphoric acid. It is of importance that the exact proportions indicated of
the phosphoric acid, lime and water, should be used in the production of this solid
phosphoric acid. An excess of which lime would render the phosphate insoluble in
water; an excess of phosphoric acid would prevent its desiccation, and too great a.
quantity of water would partially decompose the solid substance. The temperature
also should not be allowed to rise considerably during the reaction. In order
to obtain a good result, the product should solidify rapidly, and should dry >
spontaneously at ordinary temperatures, and it should be readily pulverised at the
end of four or five days.

page_text: The pure triple phosphate of lime should be perfectly soluble in water; any
insoluble parts it may contain are due to the presence of iron in the phosphoric acid.
The phosphate of iron existing in the mass is always soluble in citrate of ammonia;
it is therefore assimilable by vegetables.
The solid phosphoric acid presents advantages that will be appreciated by every
one; it is evidently destined to replace in the manufacture of manures all the other
phosphates of lime. It affords agriculture a very intense phosphoric agent, as it
contains from 48 to 50 per cent of phosphoric acid. Its well defined, invariable
and easily ascertained constitution renders all fraud impossible; its transport offers
no difficulty, as the triple phosphate does not act upon the sacks. When mixed by
the manure merchant or agriculturist with variable quantities of sand, earth,
plaster, &c, the triple phosphate can form superphosphates of variable energy.
As the solidified phosphoric acid does not contain substances useless to agriculture,
which are present in such large quantities in all the superphosphates, it is
particularly suited for exportation.
The following will serve to shew clearly the advantages of the new product, and
the differences which distinguish it from the phosphatic manures heretofore used.
It has long been the custom to enrich the superphosphates by the addition of
phosphoric acid; this operation affords superphosphates of great richness, but
which present the inconveniences and uncertainty of all superphosphates:
Their composition is not uniform; they are never entirely soluble in water and
citrate of ammonia; they are almost always deliquescent and their acidity destroys
rapidly the sacks in which they are transported; they are frequently subject to
spontaneous retrogression, whereby the proportion of the assimilable part is made
to vary.
The above described solid phosphoric acid is characterised by a special synthetic
manufacture, and by a combination of properties which give it an incontestable
stamp of novetly.
The following are the characteristic features of the invention:
1, The synthetic production of the triple phosphate of lime by the direct action
of lime upon phosphoric acid.
2, The formation of a phosphate that solidifies immediately, resembling the
action of plaster of paris; the conditions of this solidification are difficult to
determine, they depend upon the purity of the acid, upon its concentration, the
intimacy of the mixture, the temperature generated at the moment of reaction, the
proportion and nature of the lime employed. The operation does not succeed if
some of these conditions are neglected.
3, The economic preparation of a phosphoric acid sufficiently pure for forming a
triple phosphate perfectly soluble in water.
4, The avoidance, in the desiccation of the new phosphate, of the use of artificial
heat which always decomposes a portion of the soluble principle.
5. When the mixture of phosphoric acid and of lime has been made under
suitable conditions, the product, when exposed to the atmosphere, should be dry in
four or five days.
It will be seen therefore that if the principle of the operation is simple, the
details of the manufacture have to be carried out with care and that the
combination thereof constitutes in reality a new industry. Agriculturists will, in
effect, find for the first time in this new triple phosphate, a very intense phosphatic
manure which does not undergo changes in the air, the composition of which does
not vary, which is suited to the production of phosphates of lime of different
qualities, and is of great value for exportation, in not containing inert matter; and
lastly, the constituents of which are all assimilable by vegetables.
Having thus described the nature of the said invention and in what manner the
same is to be performed as communicated to me by my foreign correspondent, I
claim :-
First: The method herein described of solidifying phosphoric acid by means of
lime for the production of a solid phosphate all the constituents of which are

page_text: assimilable, non deliquescent, and completely soluble in water, containing as much
anhydrous phosphoric acid as existed in the sirupy liquor employed in its
production.
Second: The manufacture of a solid non-deliquescent phosphate of lime soluble
in water by the addition of lime or its compounds to hydrated phosphoric acid,
substantially as herein described.
Third: The use of the solid phosphoric acid above referred to, for the production
of superphosphates of varying strengths, substantially as herein described.
In Witness whereof, I the said Charles Denton Abel have hereunto set my hand
and seal this third day of May in the year of our Lord one thousand, eight hundred
and eighty-four.
CHAº, D. ABEL (L.S.)