Note: Descriptions are shown in the official language in which they were submitted.
20566~9
90-445
BACKGROUND OF THE INVENTION
The present invention is drawn to a method for
producing a fertilizer composition and a fertilizer
composition per se which is characterized by high
mechanical resistance and anti-caking properties while
maintaining a high capacity of dissolution.
Heretofore, one of the primary problems encountered
when handling, transporting and storing fertilizers is
the fact that the fertilizers tend to lump. In
addition, known fertilizer compositions fail to have an
acceptable degree of hardness or resistance to
fracturing. It is common in the prior art to provide
additives to the fertilizer which alter the manner of
crystallization of the fertilizer during the forming of
the fertilizer into a final desired product. U.S.
Patents 3,112,343, 4,160,782 and 4,204,053 disclose
varioUs processes for the treatment of fertilizers with
additives such as formaldehyde in an effort to eliminate
the problems as aforesaid. Formaldehyde has been
designated by the U.S. Environmental Protection Agency
as a toxic chemical and a potentially carcinogenic
substance. Accordingly, alternate additives have been
employed in fertilizers in an attempt to reduce the
fragility of the fertilizer and its tendency to lump.
U.S. Patent 4,587,358 discloses a fertilizer composition
which employs lignosulphonates as an additive to improve
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2û5~
the foregoing properties. U.S. Patents 4,743,289 and
4,846,871 likewise disclose improved fertilizer com-
positions employing additives which tend to increase
the mechanical resistance to the fertilizer as well as
the anti-caking properties thereof.
Naturally, it would be highly desirable to pro-
vide a fertilizer composition and method for making
same which is characterized by high mechanical
resistance and anti-caking properties while at the
same time being non-toxic, non-carcinogenic and
relatively inexpensive to manufacture.
Accordingly, the present invention seeks to
provide an improved fertilizer composition and method
for making same wherein the fertilizer is
characterized by high mechanical resistance and anti-
caking properties.
In particular the present invention seeks to pro-
vide a fertilizer as aforesaid which includes an
additive in the form of a hydrosoluble lignate salt.
Still further the present invention seeks to pro-
vide a fertilizer and method as aforesaid which
employs a hydrosoluble lignate salt as an additive
wherein the lignate salt is derived from waste mate-
rials developed in paper pulp factories.
Still further the present invention seeks to pro-
vide a fertilizer and method as aforesaid which is
inexpensive, non-toxic and non-carcinogenic.
2a5~6~
Further advantages of the present invention will
appear hereinbelow.
SUMMARY OF THE INVENTION
In accordance with the present invention, the
foregoing advantages are readily obtained.
The present invention is drawn to a fertilizer
composition and a method of making same wherein the
fertilizer is characterized by a high degree of
mechanical resistance and anti-caking properties. In
accordance with the present invention, the fertilizer
composition comprises a compound selected from the
group consisting of urea, ammonium sulphate, nitrogen-
potassium-phosphorus granulates, mono-ammonic phos-
phate, di-ammonic phosphate, potassium chloride and
mixtures thereof and a sulphur free hydrosoluble
lignate salt selected from the group consisting of
sodium lignates, alkaline metal lignates, ammonium
lignates, and mixtures thereof in an amount of between
0.1 to 5.0 wt.% in the final fertilizer composition
such that said fertilizer formula possesses a high
mechanical resistance and a low tendency to lumping
without affecting the capacity of dissolution thereof.
In accordance with a preferred embodiment the present
invention, the hydrosoluble
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90-445
lignate salt is a sulphur free sodium lignate which is
derived from waste products from paper pulp factories.
Preferred compounds for use in the fertilizer
composition are urea, ammonium sulphate, potassium
chloride, mono ammonium phosphate and diammonium
phosphate with urea being a common nitrogen carrier. By
employing an addition of a lignate salt, the resulting
fertilizer is characterized by a greater resistance to
compreSsion and impact as well as a reduced tendency for
lumping.
The method for producing the fertilizer of the
present invention comprises mixing the compound and
lignate salt so as to produce a homogeneous mixture
thereof and thereafter heating the mixture in a furnace
to a temperature of between 120 and 160C and thereafter
processing the mixture so as to obtain a desired
particulate material form. In accordance with the
preferred embodiment of the method of the present
invention, the sodium lignate results from processing
paper pulp.
The fertilizer of the present invention and method
for making same results in a non-toxic, non-carcinogenic
fertilizer composition which is characterized by high
mechanical resistance and good anti-caking properties.
2 ~ 5 ~ 6 !~
90-445
DETAILED DESCRIPTION
A waste material produced in paper pulp factories
referred to as "soda liquor" consists essentially of a
solution of lignates. In the treatment step in the
paper pulp factories, the raw materials are processed
with sodium hydroxide which results in a "soda liquor"
wherein the lignates are mainly sodium lignates.
In order to obtain the hydrosoluble lignate salt
additive for use in the fertilizer composition of the
present invention, the "soda liquor" is dewatered so as
to produce a water solution having a concentration of
the sodium lignate of between 48 and 55 wt.~ or the
water is totally eliminated so as to result in a water
free lignate powder.
While sodium lignates are particularly suitable as
additives in the fertilizer of the present invention, it
should be appreciated that other lignates such as
alkaline metal lignates and ammonium lignates can
likewise be used. Furthermore, the lignates may contain
other material such as polysaccharides and/or
monosaccharides and/or salts from acids contained by the
degradation of carbohydrates during the pulping
operation. These may be present in the lignate without
altering its properties relative to mechanical
resistance and anti-caking. In a preferred embodiment
of the present invention, the lignate salt is derived
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from a raw material used in the paper pulp fabrication
which is preferably sugar cane bagasse; however, other
vegetable material can be used which contains at least
15 wt.% lignin.
In accordance with the method of the present
invention, the hydrosoluble lignate salt is admixed with
a compound selected from the group consisting of urea,
ammonium sulphate, nitrogen-potassium-phosphorus
granulates, mono-ammonic phosphate, di-ammonic
phosphate, potassium chloride and mixtures thereofO As
noted above, the hydrosoluble lignate salt is selected
from the group consisting of alkaline metal lignates,
ammonium lignates, and mixtures thereof in an amount of
between 0.1 to 5.0 wt.~ in the final fertilizer
composition such that said fertilizer formula possesses
a high mechanical resistance and a low tendency to
lumping without affecting the capacity of dissolution
thereof. In accordance with the present invention, the
preferred hydrosoluble lignate salt is a sulphur free
sodium lignate and the compound which it is mixed with
is preferably urea. When urea is used as the compound,
the lignate salt should be present in the final
fertilizer composition from 0.1 to 1.0 wt.~. When
ammonium sulphate is used as the compound, the
hydrosoluble lignate salt is present in the final
fertilizer composition in an amount of 2.6 to 4.8 wt.%.
20566~9 90-445
In accordance with the present invention, the
compound and the hydrosoluble lignate salt are mixed
together so as to produce a homogenous mixture. The
homogeneous mixture is thereafter heated to a
temperature of from 120 to 160C and thereafter
processes by the well known prilling into final
particulate form.
As noted above, the lignate salt is obtained from
waste products produced during the process of paper
pulps and the raw material used in the processing is
usually sugar cane bagasse.
The properties of the fertilizer of the composition
are comparable to known fertilizer compositions and it
will be demonstrated hereinbelow with regard to the
examples. The hardness or mechanical resistance of the
fertilizer has two components. The first component
being the resistance to compression which is a static
force and the second component being resistance to
impact which is a dynamic force. The resistance to
compression is determined in accordance with Chatillon
Hardness Compression and employs a device manufactured
by John Chatillon & Sons under Model No. LTCM-3 under
International Fertilizer Development Center Standard
S-115. The resistance to impact is determined under
International Fertilizer Development Center Standard
F-118. The tendency to lump is evaluated by means of
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90-445
accelerated caking tests. Such tests consist of placing
a certain quantity of prills in the interior of a hollow
cylinder and entrapping the prills between two
plexiglass pistons. After an established amount of
time, a small cake is obtained which is then subject to
fracture. The force required to fracture the cake is
determined with a penetrometer. The lower the force,
the less caking has occurred.
The foregoing examples will demonstrate the quality
of the fertilizer of the present invention when compared
to known fertilizer compositions.
EXAMPLE I
A "soda liquor" having a total solids content of 8
wt.% was dewatered so as to obtain a solution having a
solids content of 51 wt.%. The concentrated liquor was
mixed with solid urea in two different batches so as to
obtain a final product in Test 1 of 0.5 wt.~ lignate
salt and in Test 2 of 0.7 wt.% lignate salt. Each of
the test fertilizers were thereafter mixed so as to
obtain a homogeneous blend and thereafter the mixtures
were melted in a furnace at a temperature of 140C.
Observation indicated that the lignates became very
soluble in the melted urea and that the urea lignate
solutions did not present any turbidity whatsoever.
Thereafter the mixture was cooled and prilled in a known
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90-445
manner so as to obtain particles of various diameters.
After pearling, the prills were screened to separate
them by sizes into 10 mesh, 12 mesh and 14 mesh.
A further Test 3 fertilizer composition was
produced by adding powdered lignate salt to urea so as
to produce a final fertilizer composition of lignate
salt of 0.5 wt.~. The mixture was thereafter blended so
as to form a homogeneous mixture and heated and prilled
and separated in the same manner of Tests 1 and 2. In
order to demonstrate the behavior of the fertilizer
compositions of the present invention, their resistance
to compression was determined in accordance with
Chatillon Hardness Compression and compared to two known
fertilizer compositions containing urea and an additive
and a fertilizer consisting solely of urea. The two
known fertilizer compositions were as follows: UF-85 ,
of Allied Chemicals (U.S.A.) and Norlig -HP , of
Daishowa Chemicals (U.S.A.). The results of the
compression tests are set forth below in Table I.
--10--
2~6~9
90 -445
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--11--
2 ~ 9
90-445
As can be seen from Table I, the fertilizers of the
present invention exhibit a resistance to compression
which is superior to that of either of the known
fertilizer compositions. In addition to the foregoing,
the resistance to impact was measured in accordance with
IFDC-118 Standard and the results are again shown
hereinbelow in Table II.
90-445
20566~9
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--13--
2~56649 90-445
As can be seen from Table II, the resistance to
impact of the fertilizer compositions of the present
invention are comparable to those obtained by the known
fertilizer compositions.
EXAMPLE II
The fertilizers employed in Example I were
subjected to caking tests in accordance with the
procedure described above and the results of these
caking tests are shown in Table III hereinbelow.
-14-
2056649 90-445
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2~a~9
90-445
Again, it can be seen that the caking tendencies of
the fertilizer compositions of the present invention are
at worst comparable to and in many cases better than the
caking tendencies of the known fertilizer compositions.
EXAMPLE III
In order to demonstrate the effectiveness of other
compositions of the fertilizer of the present invention,
a sodium lignate powder was mixed with nitrogen-
potassium-phosphorus granulates having a formula of
15-15-15-solid so as to produce a final lignate
composition of 5 wt.%. A second formulation was made by
mixing a nitrogen-potassium-phosphorus granulate having
the formula 13-26-06 with sodium lignates so as to
obtain a final composition of 2.8 wt.% lignate. Caking
tests were again run in order to compare the effect of
the additive of the present invention on those
fertilizer compositions and those results are given
hereinbelow in Table IV.
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2~66~9
90-445
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--17--
2 0 5 6 6 ~ 9 90-445
It can be seen from Table 4 that the additive
compound of a lignate salt in accordance with the
present invention greatly reduces the caking tendencies
of known fertilizers.
This invention may be embodied in other forms or
carried out in other ways without departing from the
spirit or essential characteristics thereof. The
present embodiment is therefore to be considered as in
all respects illustrative and not restrictive, the scope
of the invention being indicated by the appended claims,
and all changes which come within the meaning and range
of equivalency are intended to be embraced therein.
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