Note: Descriptions are shown in the official language in which they were submitted.
CA 02229493 1998-03-13
SUBSTANTIAT-T.Y DUST-F~F~ sor~IDs A~D PROC~SS
FOR DUST SUPP~SSION IN SOLIDS
FIELD OF THE INVENTION
The present invention relates generally to solid
state materials and it has particular application for
suppressing dust formation in solid state fertilizers.
~ACKGROUND OF THE INVENTION
The generation of dust in the handling of certain
finely divided solid material~ or in the handling of "fines"
present among larger particles, is a known problem. One area
where this problem has been observed is in the handling of
fertilizer materials. Dust is frequently generated in the
handling of dry fertilizers. ~Dust can be a nuisance and may
pose safety and health hazards. Dust problems are particularly
severe in bulk fertilizer production and in distribution
facilities that handle large quantities of dry fertilizers.
When loading or unloading large quantities of such materials,
the dust generated results Ln poor working conditions. A
portion of the solid is lost and the surrounding may be
contaminated with the settling dust. The United States
Government has issued regulations to control dust exposure in
the work place and to limit the amount of dust released into
the environment.
The problem of preventing dust formation has been
handled by spraying a liquid onto the solid material. Examples
of this may be found in U.S. Patent No. 3,393,973, to Almy,
(tall oil sprayed on potash); U.S. Patent No. 4,717,555 to
Newman, et al. (naphthalene sulfonates and water on ammonium
salts preventing caking and dust formation); and U.S. Patent
No. S,041,153 to Detroit (lignosulfonate treated inorganic
chemicals resist caking and dust).
Waxes and oils have also been applied to fertilizer
CA 02229493 1998-03-13
powders to prevent dust formation. Such is described in
European Patent Publication No. 0 255 665.
Russian Inventor's Certificate No. 2019535 Cl
describes the use of glycerol residuum (bottoms formed in the
distillation of crude glycerol) applied to potassium chloride
as an anti-dusting agent.
Ammonium sulfate has been granulated to improve
particle size distribution. U.S. Patent No. 4,277,253 to Walter
et al. describes the granulation of ammonium sulfate and other
fertilizer ingredients.
Lobeco Products Inc. offers an anti-caking and anti-
dusting product under the name GalorylTM ATH 632. Galoryl ATH
632 is a solid at ambient temperature and must be heated (to
about 80~C) to the liquid state before application. This adds
to the handling difficulty and contributes to the safety
precautions that must be in place to prevent burns from
spillage of heated liquids.
In addition to the handling difficulties, such sprays
are expensive and add significantly to the production cost of
free-flowing, dust-free granules. Therefore, there remains a
need for safely and economically producing granules that remain
free-flowing and dust-free even after storage and shipping.
Water is an effect:ive anti-dusting agent. Water,
however, usually causes the material, e.g., ammonium sulfate,
to cake. An effective anti-dusting agent will not contribute to
the caking problems observed with many of the solid materials
to which the present invention relates.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention
to provide granules, like ammonium sulfate, that is
substantially dust-free.
It is another object of the present invention to
provide a process for making granules that are substantially
dust-free.
CA 02229493 1998-03-13
These and related objects and advantages are achieved
with a substantially dust-free solid that is treated with a
blend of water and distillation bottoms.
Also provided is a process for hindering the tendency
of a solid to generate dust by treating the solid with such
distillation bottoms.
The distillation bott;oms that are used in accordance
with the liquid at about 60~C' or less and are obtained from
production of an alcohol having the formula:
R2-Rl-OH
wherein Rl is substituted or unsubstituted branched, straight
chain or cyclic C4 to Cl2 and R2 is OH or H.
The preferred distillation bottoms are distillation
bottoms from the production of hexanediol. The blend may be up
to about 50% by weight water. The solid may be any solid that
thas a tendency to form dust on storage, shipment or use. When
the solid is a fertilizer, it may be potassium chloride;
potassium nitrate; potassium chloride; and ammonium sulfate;
ammonium nitrate; sodium nitr~te; potassium nitrate; calcium
nitrate; urea; diammonium phosphate; ammonium polyphosphate;
monoammonium phosphate; triple superphospahte; ammonium
chloride; potash; or mixtures of thereof. Others solids,
however are made dust free through the use of the present
invention. The preferred application rate is generally about 2
to about 40 lb./ton solid.
Another object of the present invention is to provide
granules that are substantial;Ly dust-free and do not tend to
cake on storage and shipment.
In addition, the present invention includes treated
solids that are in the form of unpaved thoroughfares such as
gravel parking lots and gravel or dirt roads.
In addition, the present invention includes treate~
solids that are in the form of unpaved thoroughfares such as
gravel parking lots and gravel or dirt roads to reduce dust
CA 02229493 1998-03-13
formation due to vehicular traffic, etc.
Related objects and advantages will become apparent
to those of ordinary skill in the art to which the invention
pertains after reading the following detailed description of
the invention.
DETAILED DESCRIPTION OF THF PREFERRED EMBODIMENTS
The invention will ilOW be described with specific
language. No limitation should be inferred due to the specific
language. Reasonable modifications, equivalents and further
embodiments, as will be readily envisioned by the ordinarily
skilled in this art, are considered within the scope of the
present invention.
The solids handling industry uses different terms to
describe solids. "Powder" generally defines a very fine or
dust-like material. "Granules" refer to larger particles that
have more mass. "Particulate" is another term that is used.
Agriculturists want to apply granular materials because they
spread uniformly. Lighter mat;erials are more difficult to
spread uniformly on fields, especially on windy days. During
the solids handling process, however, breakage occurs and dust
or fines are generated. It should be understood in reading the
following detailed description of the present invention that
the term "granules" is not used in any limiting sense and
applies to granular materials as well as fines, powders,
particulate, combinations of these, etc.
One aspect of the present invention is a process for
suppressing dust formation in the solid by applying to the
solid, the distillation bottoms from the production of an
alcohol having the formula:
R2-R1-OH,
wherein R1 is substituted or unsubstituted, branched, straight
chain, or cyclic C4 to C12 and R2 is OH or H. Such distillation
CA 02229493 1998-03-13
bottorns are diluted with water or other liquid and are in the
liquid state at 60OC or less. It is surprising that this by-
product stream can be effectively used to suppress the tendency
of solids to dust without promoting caking on storage and
shipment.
The useful distillat;ion bottoms (sometimes called
"distillation heavies") are a by-product of the production of
alcohols according to the formula:
R2-Rl--OH,
wherein Rl is substituted or unsubstituted, branched, straight
chain, or cyclic C4 to C12 and R2 is OH or H. Preferably, the
distillation bottoms are the by-product of the production of
1,6, hexanediol. While not wishing to be limited to the exact
proportions of materials present in such bottoms, which may
vary as will be understood by those ordinarily skill in the
art, the following are exemplary components of 1,6 bexanediol
distillation bottoms (in percent by weight determined by gas
chromatography): 1,6 hexanediol ~3.0-9.6), 6,6'dihydroxydihexyl
ether (2.8-9.9), oligomers (1l.5-14.0), various other diols,
esters and ethers (73.6-76.E~), and water (0.2-0.3). 1,6
hexanediol distillation bottoms is a dark liquid that freezes
at about -54~C.
The present invention is applicable to a variety of
granules that tend to dust. Such materials are found in many
industries such as food, cosmetic, mining, sodium chloride,
etc., industries. The reference to the fertilizer industry and
fertilizer granules in this det~iled description is, therefore,
not considered to limit the present invention to the fertilizer
industry. Exemplary granules include ammonium sulfate, ammonium
nitrate, sodium nitrate, potassium nitrate, calcium nitrate,
urea, diammonium phosphate, ammonium polyphosphate, mono-
ammonium phosphate, triple s,uperphosphate, urea, ammonium
chloride, potash, potassium chloride, potassium nitrate,
potassium chloride and mixtures of these with other granules
CA 02229493 1998-03-13
and with each other. Preferably, the granules are fertilizer
granules and most preferably annnonium sulfate and mixtures
thereof.
The distillation bottoms are preferably mixed with
water or another equivalent solvent before application to the
solid. As demonstrated in the Examples below, even when mixed
with water prior to application, the distillation bottoms did
not promote caking of ammonium sulfate fertilizer granules.
Mixing with water may be preferred to reduce the viscosity of
lo the distillation bottoms and make them more manageable in the
field. The distillation bottoms may be diluted with up to about
50% (or more) by weight water. It should be noted that phase
separation may occur at higher l~ilution levels (about 50%) but
this is not considered detrimental to effectiveness in dust
suppression.
The distillation botloms may be applied by spraying
directly on the granules or by other methods of application.
Spraying is the currently preferred method. Spraying may be
accomplished, for example, by pumping the dust suppressing
agent through a spray nozzle which directs the dust suppressing
agent on to the material to be treated. The material is
preferably treated during conveyance from production to
storage, but may be treated at; any time in the production to
use cycle. Various methods of pumping (i.e., types of pumps,
use of a vapor pad to move the dust suppressing liquid, etc.)
can be used as well as various types of nozzles (distributors,
mixing drums, etc.). Many types of conventional and novel
equipment can be used for this application. The dust
suppressing age~t should be applied in an approximately uniform
layer on the treated material. It is preferably applied during
the conveyance of the material into a storage container or the
like. In some cases, the distillation bottoms may be heated
before application, but this i-, not essential.
The rate of application will depend on the end use
for which the solids are intended. In the case of fertilizers,
the application rate is preferably in the range of about 2
CA 02229493 1998-03-13
pounds to about 40 pounds per ton of granules. More preferably,
the application rate is about 4 pounds to about 12 pounds of
distillation bottoms per ton oi granules.
In addition, the distillation bottoms may be applied
to unpaved thoroughfares, such as gravel parking lots, dirt
roads and driveways, gravel roads and driveways, and other
surfaces where dust formation is a problem. In the case of
thoroughfares, application of the distillation bottoms will
suppress dust formation due to traffic on such surfaces. The
distillation bottoms may be applied by any conventional means
for applying dust suppression agents to such surfaces. The
distillation bottoms may or may not be mixed with water or an
equivalent solvent.
Another aspect of the present invention is a
substantially dust-free solid treated with the distillation
bottoms from the production of an alcohol having the formula:
R2-Rl--OH
wherein R1 is substituted or unsubstituted, branched, straight
chain or cyclic C4 to C12 and R2 is OH or H. Such distillation
bottoms are in the liquid state at about 60~C or less.
The useful distillation bottoms are described in more
detail above in connection with the process aspect of the
present invention. The preferred heavies are from the
production of 1,6 hexanediol as described previously.
The treated solid of the present invention may be any
one of a variety of granules that tend to create a substantial
arnount of dust. Such materia]s are found in many industries
such as food, cosmetic, mining, sodium chloride, etc.,
-industries. As noted in connection with the process of the
present invention, the reference to the fertilizer industry and
fertilizer granules in this detailed description is not
considered to limit the present invention to the fertilizer
industry. Exemplary granules include ammonium sulfate, ammonium
nitrate, sodium nitrate, potassium nitrate, calcium nitrate,
CA 02229493 1998-03-13
urea, diammonium phosphate, ammonium polyphosphate, mono-
ammonium phosphate, triple superphosphate, urea, ammonium
chloride, potash, potassium chloride, potassium nitrate,
potassium chloride and mixtures of these with other granules
and with each other. Preferably, the solid granules are
fertilizer granules and, most preferably, ammonium sulfate and
mixtures thereof.
To make the treated solid of the present invention,
the distillation bottoms may be applied by spraying directly on
the granules as described above in connection with the process.
The distillation bottoms may be diluted up to about 50% by
weight (or more) with water or another solvent. The rate of
application is in the range of from about 2 pounds to about 40
pounds per ton of the solids to be treated. Preferably, the
application is at a rate of about 4 to about 12 lb. distilla-
tion bottoms per ton of the so]id to be treated.
The treated solid of the present invention may be an
unpaved thoroughfare such as a parking lot, gravel road, dirt
road, unpaved driveway, etc. The treated solid in the form of
such a thoroughfare will resist dust formation from vehicular
travel. The distillation bottoms may or may not be diluted with
water or another solvent prior to treating the thoroughfare.
The invention will now be described in the following
specific examples, however, no limitation on the scope of the
invention should be inferred from the specific details of these
examples. All percentages are by weight unless indicated to the
contrary.
COMPARATIYE ~xAMpLE
Untreated ammonium sulfate is conveyed from a
production unit to a storage bin. Dust formation during
conveyance is severe.
~X~MPLE 1 - DUST SUPPRESSION
CA 02229493 1998-03-13
During conveyance from a production unit to a storage
bin, ammonium sulfate is sprayed at a rate of about
gallon/ton (about 8 lb./ton) distillation bottoms from the
production of l,6, hexanediol that have been diluted about lO
to about 50% with water. Dust i-ormation is minimal.
~XAMPT.~S 2A - 5B CAKING TEST
In Examples l-4, distillation bottoms from the
production of l,6 hexanediol are diluted with 15%, 20%, 25% and
30% water, respectively. For t;he "A" series of examples, the
diluted bottoms are sprayed on ammonium sulfate granules at a
rate of about 4 lb./ton. For 1;he "B" series of examples, the
diluted bottoms are sprayed on ammonium sulfate granules at a
rate of about 8 lb./ton. An untreated ammonium sulfate sample
is used as a control.
Test cakes are made from the treated ammonium sulfate
and the untreated control. These cakes are made by placing
ammonium sulfate in test cells and applying a pressure of 2
tons for one minute with a hydraulic press. A force gauge is
used to record the force that is needed to break each cake.
Five breaking tests are conducted for each example. The average
force is reported in the table below.
CA 02229493 1998-03-13
Table - Cake Breaki~P Stren~th
SAMPLE BREAKING STRENG~H (Ib.)
Control 20
2A: 15%dilution ~4 Ib./ton 12
2B: 15% dilution ~ 8 Ib./ton 11
3A: 20% dilution ~ 4 Ib./ton 14
3B: 20% dilution ~ 8 Ib./ton 10
4A: 25% dilution (~ 4 Ib./ton 15
4B: 25% dilution (~ 8 Ib./ton 11
5A: 30% dilution ~ 4 Ib./ton 13
5B: 30% dilution ~ 8 Ib.l~on 12
