An Improved Process for Making a Consistent Friable Artificial Manure.
Year: 1897

page_text: COMPLETE SPECIFICATION.
An Improved Process for Making a Consistent Friable Artificial
Manure.
I, IMRE KOVACS, of 35, Eötvösgasse Budapesth in the Kingdom of Hungary,
Chemist, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
According to recent experiments and investigations it is preferable in many cases not to
allow the phosphoric acid, employed for manurial purposes, and which is soluble in water,
to come into the earth in the form of mono-calcic phosphate СaH, (PO) 2 H₂O,
but in the form of ortho-phosphoric acid H,PO.. Thus for instance better results
are obtained in manuring a ground rich in lime with ortho-phosphoric acid, than with
mono-calcic phosphate (superphosphate). Also the circumstance that the free phos-
phoric acid is not fully combined with the uppermost layer of soil, but penetrates
deeper into the ground so that the acid stands at the disposal of the plants even in
their later periods of development, speaks volumes for the preferable use of this
phosphoric acid. Further, free ortho-phosphoric acid and materials containing ortho-
phosphoric acid and free sulphuric acid may be employed for preserving stable manure,
for which object these substances according to the previously mentioned experiments
have been found the most effective.
The inventor has established by his investigations that free phosphoric acid and
especially substances containing free phosphoric acid and free sulphuric acid may
also be utilised with the greatest success for improving and manuring ground
containing alkali or soda.
Finally, such an artificial manure as contains ortho-phosphoric acid in a free
condition, and in addition an excess of sulphuric acid, is desirable for the reason that
it allows many phosphates which contain iron and alumina to be treated in this
manner cheaper than with the processes hitherto known.
As is well known, phosphates which contain much iron and allumina cannot be
employed for the manufacture of superphosphate without first neutralising or
separating out the said substances by an expensive and inconvenient process, as the
mono-calcic phosphate, formed in consequence of the treatment, becomes in a short
time again insoluble (goes back) under the action of the said constituents.
If however to such phosphates such a quantity of sulphuric acid be added that all
the phosphoric acid is converted into a free condition, and there be still present an
excess of sulphuric acid, the iron and alumina cannot exert their deleterious influence.
The practical use of free ortho-phosphoric acid has been prevented hitherto by the
circumstance that it is very expensive, and also that it does not come into commerce
in the form of a consistent friable artificial manure but in the form of a liquid. This
form is however for agricultural purposes not only expensive but its practical utilisa-
tion encounters many technical difficulties.
Such an artificial inanure in which the whole of the phosphoric acid is contained in
a free condition in the form of ortho-phosphoric acid, remains pulpy and stringy,
does not become hard and cannot be distributed; consequently there was hitherto

page_text: '
only known in commerce the anhydrous phosphoric acid in the form of superphosphate
containing the phosphoric acid preferably as mono-calcic phosphate.
This defect is essentially removed according to the process which forms the object
of the present invention by the addition of absorbent substances, more particularly
peat. By this addition, the pulpy, stringy soft product produced by the free phos-
phoric and sulphuric acid and uncombined water, is converted into an artificial easily
distributed manure.
The practical carrying out of the process is effected as follows:-
Mineral phosphates, bones, bone ineal, bone ash, or other phosphatic raw material
is treated with enough sulphuric acid to set at liberty the entire amount of phosphoric
acid contained in the raw material and to leave an excess of sulphuric acid. The
excess of acid may amount to about 10°, but it varies between wide limits according
to the quality of the raw material and the object for which the products are to be
employed. Sulphuric acid of about 50° Beaumé in strength has been found the most
advantageous to employ for the treatment. A weaker or stronger may, however, be
employed according to requirements. The free ortho-phosphoric acid, formed in con-
sequence of the action of the sulphuric acid, and the excess of sulphuric acid cause
the product to assume a pulpy, thready, moist condition. In order to remove this
condition or to absorb the water not combined by the acids and other compounds
present, turf or peat is then employed. A peat meal free from earthy constituents
is preferably employed. Sawdust, kieselguhr, infusorial earth, ground spent tan, or
other moisture absorbing substance may however be employed if desired instead of
peat, so long as such substances do not contain substances which might bind or combine
with the free phosphoric acid or sulphuric acid.
The peat or other absorbent material may also be mixed with the sulphuric acid and
the raw material, but as the high temperature produced by the action of the sulphuric
acid partially carbonises the peat or the organic constituents of the other absorbent
substances employed, it appears preferable under most circumstances to mix the
absorbent materials with the treated pulpy mass only when this latter has somewhat
cooled down.
The carbonisation has indeed no influence on the condition and the solubility of
the phosphoric acid, but a maintenance of the organic materials is desirable, and it is
also desirable to avoid any carbonisation of the same, because the destroyed absorbent
material must subsequently be replaced by fresh.
As regards the quantity of peat employed, it is preferable to employ about 30°
in weight of the total sulphuric acid employed, but the quantity of course alters with
the absorbent properties of the absorbent material employed, and with the quantity
of the excess sulphuric acid.
For carrying out the process herein before described, the treating or mixing machines
used in the manufacture of superphosphate may be utilised. The fine ground raw
phosphate or other suitable phosphatic raw material is simultaneously conveyed into
the decomposing or treating machine together with a measured quantity of acid,
precisely as in the process employed for the manufacture of superphosphate.
After the sulphuric acid and the raw material have been stirred together for about
a minute in the treating or mixing machine, the peat or other absorbent material in
weighed quantities is introduced through a special opening arranged for this object,
or through the opening employed for introducing the raw inaterial into the machine.
.After a renewed stirring of about one minute's duration, the entire mass, as in the
superphosphate manufacture, is conveyed into a chamber arranged beneath or beside
the same, whilst fresh raw material, acid and turf are conveyed into the treating
machine in the manner herein before described. The mass accumulating in the
chamber is further treated in a similar manner to that of superphosphate manufacture.
After the mass has undergone the necessary period of storage and has received
the necessary disintegration and treatment, it is as a rule sufficiently friable and free
from lumps to be able to be brought into commerce without further manipulation."
If the peat or other absorbent material is only added subsequent to the mixture of

page_text: raw material and sulphuric acid, the said materials, as in the superphosphate manu-
facture, (each separate charge), are conveyed into the chamber where the mass
remains until it is sufficiently cool. Then the wet pulpy mass is again returned into
the mixing machine by means of a suitable lifting device (bucket apparatus)
and there mixed with the peat or other absorbent material which is inserted at the
same time. The process is otherwise identical with the one previously described.
Even in the superphosphate manufacture it frequently happens that a very slow
drying superphosphate is obtained or produced which contains pulpy lumps which
remain moist. In such cases, artificial drying has hitherto been resorted to, which
however not only requires expensive plant but also affects the solubility of the phos-
phoric acid. The drying of these damp and slow-drying superphosphates may be
effected by the use of the process hereinbefore described (artificial drying being
avoided) that is to say, by mixing peat or other absorbent material with them. The
superphosphates mixed with peat do not tend to form lumps of themselves and, as a
rule even without the use of disintegrators they are already in a sufficiently loose and
friable condition to be distributed.
In this case an addition of peat of about 15° of the weight of the total sulphuric
acid added will suffice. The proportionate quantities vary however of course according
to the absorbent capacity of the drying material used.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. A process for increasing the consistency and friability of artificial manures con-
taining phosphoric acid, consisting in the addition of absorbent materials, the more
particularly peat, substantially as hereinbefore set forth.
2. The application and use of the process herein before described for producing an
artificial manure containing free phosphoric acid and sulphuric acid, characterised by
the pulpy stringy soft product formned by the presence of free acid and uncombined
water being converted by the addition of absorbent materials and more particularly
peat into a consistent, thoroughly friable, manure, substantially as described.
3. A method of carrying out the hereinbefore described process, consisting in
treating the raw phosphate or phosphatic materials with as much sulphuric acid as
sets free the entire phosphoric acid and still leaves an excess of free acid, and mixing
the mass thus obtained with absorbent materials such as peat, substantially as
described.
4. The application and use of the process hereinbefore described for treating raw
phosphates or phosphatic materials which contain a large amount of iron and alumina
compounds for the purpose of preventing the retrograding (becoming insoluble) of
the dehydrated phosphoric acid resulting on the decomposition, substantially as
described.
5. The application and use of the process hereinbefore described for drying and
rendering friable, and preventing the formation of lumps in, slowly-drying superphos-
phates by the addition of absorbent materials, more particularly peat, substantially as
described.
6. An artificial manure which, in addition to free phosphoric acid and sulphuric
acid, contains an absorbent material, more particularly peat, substantially as described.
Dated this 3rd day of June 1897.
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.