U.S. patent application number 09/681562 was filed with the patent office on 2002-12-12 for polyhydric alcohol anti-dust agent for inorganic materials.
This patent application is currently assigned to Montana Sulphur & Chemical Company. Invention is credited to Bell, Fred S. III, Zink, Donald G..
Application Number | 20020184933 09/681562 |
Document ID | / |
Family ID | 24735802 |
Filed Date | 2002-12-12 |
United States Patent
Application |
20020184933 |
Kind Code |
A1 |
Bell, Fred S. III ; et
al. |
December 12, 2002 |
Polyhydric alcohol anti-dust agent for inorganic materials
Abstract
Applying a polyhydric alcohol anti-dust agent, such as glycerol,
to inorganic particulate materials reduces the formation of dust
during processing and handling. The anti-dust agent is particularly
effective for reducing dust formation in fertilizers such as
disintegrating sulfur fertilizer (DSF), without interfering with
the useful disintegration or other useful properties of the
fertilizer.
Inventors: |
Bell, Fred S. III;
(Billings, MT) ; Zink, Donald G.; (Houston,
TX) |
Correspondence
Address: |
BANNER & WITCOFF
1001 G STREET N W
SUITE 1100
WASHINGTON
DC
20001
US
|
Assignee: |
Montana Sulphur & Chemical
Company
Billings
MT
|
Family ID: |
24735802 |
Appl. No.: |
09/681562 |
Filed: |
April 30, 2001 |
Current U.S.
Class: |
71/64.07 |
Current CPC
Class: |
C05G 3/20 20200201 |
Class at
Publication: |
71/64.07 |
International
Class: |
C05G 005/00 |
Claims
1. A process of reducing the formation of dust in inorganic
particulate material comprising applying to the inorganic
particulate material an effective amount of an anti-dust agent
comprising at least one polyhydric alcohol of the formula
C.sub.nH.sub.(2n+2)O.sub.m wherein 3.ltoreq.n.ltoreq.6 and m=n or
n-1, with the proviso that m.gtoreq.3.
2. The process of claim 1 wherein the inorganic particulate
material comprises a fertilizer.
3. The process of claim 2 wherein the fertilizer comprises a
time-release fertilizer.
4. The process of claim 3 wherein the time-release fertilizer is
disintegrating sulfur fertilizer.
5. The process of claim 1 wherein the anti-dust agent is selected
from the group consisting of glycerol, erythritol, pentaerythritol,
sorbitol, mannitol, dulcitol, and blends thereof.
6. The process of claim 1 wherein the anti-dust agent comprises
glycerol.
7. The process of claim 1 wherein the anti-dust agent is applied to
the inorganic particulate material in a concentration of from about
0.2 wt % to about 2 wt % based on the total weight of the coated
inorganic particulate material.
8. The process of claim 7 wherein the concentration is from about
0.25 wt % to about 1 wt %.
9. A process of reducing the formation of dust in disintegrating
sulfur fertilizer (DSF) comprising applying glycerol to DSF
particles in a concentration of from about 0.25 wt % to about 1 wt
% based on the total weight of the coated DSF particles.
10. An inorganic particulate material having reduced dust emissions
comprising inorganic particles coated with an effective amount of
an anti-dust agent comprising at least one polyhydric alcohol of
the formula C.sub.nH .sub.(2+2)O.sub.m wherein 3.ltoreq.n.ltoreq.6
and m=n or n-1, with the proviso that m.gtoreq.3.
11. The inorganic particulate material of claim 10 wherein the
inorganic particles comprise a fertilizer.
12. The inorganic particulate material of claim 11 wherein the
fertilizer comprises a time-release fertilizer.
13. The inorganic particulate material of claim 12 wherein the
time-release fertilizer is disintegrating sulfur fertilizer.
14. The inorganic particulate material of claim 10 wherein the
anti-dust agent is selected from the group consisting of glycerol,
erythritol, pentaerythritol, sorbitol, mannitol, dulcitol, and
blends thereof.
15. The inorganic particulate material of claim 10 wherein the
anti-dust agent comprises glycerol.
16. The inorganic particulate material of claim 10 wherein the
anti-dust agent is present in a concentration of from about 0.2 wt
% to about 2 wt % based on the total weight of the coated inorganic
particles.
17. The inorganic particulate material of claim 16 wherein the
concentration is from about 0.25 wt % to about 1 wt %.
18. Disintegrating sulfur fertilizer (DSF) having reduced dust
emissions comprising DSF particles coated with glycerol in a
concentration of from about 0.25 wt % to about 1 wt % based on the
total weight of the coated DSF particles.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is directed to anti-dust agents for
inorganic particulate materials and, more particularly, to
anti-dust agents for fertilizers.
[0003] 2. Description of Related Art
[0004] Inorganic particulate materials and, more particularly,
fertilizers, such as disintegrating sulfur fertilizer (DSF),
ammonium phosphates, calcium phosphates, ammonium nitrates,
potassium nitrates, potassium chlorides, potassium sulfates, and
the like are widely used. Methods of manufacturing these inorganic
materials, as well as methods of processing the materials into
particles via prill and granulation techniques, are also known. The
inorganic particulate materials, however, often exhibit an
undesirable level of dust formation. During handling or
transportation, the inorganic particulate materials can break into
smaller particles, resulting in unacceptable levels of dust.
[0005] Dust emission from inorganic particulate materials, such as
DSF, can present ecological concerns and can be quite irritating to
persons upon short-term exposure. In some cases, dust emissions
from inorganic particulate materials can even form explosive
mixtures with air. As used herein, dust refers to airborne
particles, the majority of which are about 10 microns or smaller,
created during the production and handling of fertilizers and other
inorganic particulate materials.
[0006] Because of difficulties associated with manufacturing
useable particulate fertilizer that does not emit unacceptable
levels of dust, special anti-dust treatments often have been
applied. Generally, anti-dust treatments for inorganic particulate
materials, such as fertilizers, have focused primarily on
petroleum-based products, mineral oils, and waxes. Each of these
treatments presents disadvantages. For example, oils tend to
volatilize and/or soak into the fertilizer with time and lose their
effectiveness, while waxes and petroleum-based products are
difficult to handle, and can require special heated application
equipment. Inorganic particulate materials coated with
petroleum-based products can generate residues on handling
equipment, and, in the case of coated fertilizers, typically result
in the separation of scum upon dissolution of the fertilizer in
water.
[0007] One example of a petroleum distillate residue used as an
anti-dust agent for phosphate and other fertilizers is Dustrol
3079.TM. or Arr-Maz 3670.TM.. Petroleum-based materials of this
type have a relatively high viscosity and must either be heated or
diluted with a volatile solvent in order to be coated onto
particles. Petroleum distillate residue material produces a sludge
that can clog filters during spray application. The petroleum
distillate residue material also can adversely affect the color of
the fertilizer. For example, Dustrol 3079.TM. turns DSF particles
black, particularly when the residue material is recycled.
[0008] There remains a need for a more efficient and cost effective
anti-dust agent for inorganic particulate materials, and especially
for fertilizers such as DSF. It would be particularly desirable to
develop an anti-dust agent for DSF that does not interfere with the
useful disintegration of the fertilizer and that is environmentally
safe.
SUMMARY OF INVENTION
[0009] According to one aspect of the invention, a process of
reducing the formation of dust in an inorganic particulate material
comprises applying to the inorganic particulate material an
effective amount of an anti-dust agent. The anti-dust agent
comprises at least one ppolyhydric alcohol represented by the
formula C.sub.nH.sub.(2n+2) O.sub.m wherein 3.ltoreq.n.ltoreq.6 and
m=n or n-1, with the proviso that m.gtoreq.3. A preferred
polyhydric alcohol is glycerol. The process is particularly
effective for reducing dust formation in fertilizers, including
time-release fertilizers such as disintegrating sulfur fertilizer
(DSF).
[0010] According to another aspect of the invention, an inorganic
particulate material having reduced dust emissions comprises
inorganic particles coated with an effective amount of an anti-dust
agent. The anti-dust agent comprises at least one polyhydric
alcohol.
[0011] The polyhydric alcohols of the present invention are
efficient and cost effective agents for reducing dust formation in
inorganic particulate materials, overcoming the drawbacks of
previous oil- petroleum-, and wax-based anti-dust agents. The
polyhydric alcohols of the present invention also are
environmentally safe. Advantageously, when used with fertilizers
such as DSF, the polyhydric alcohols do not interfere with useful
disintegration of the fertilizer or otherwise adversely affect its
useful properties and characteristics.
DETAILED DESCRIPTION
[0012] The invention will be described primarily with reference to
anti-dust treatments for fertilizers, particularly disintegrating
sulfur fertilizer (DSF). It is to be understood that anti-dust
treatments for other fertilizers, as well as for other inorganic
particulate materials, are within the scope of the present
invention. Non-limiting examples of other types of fertilizers
include ammonium phosphates, calcium phosphates, ammonium nitrates,
potassium nitrates, potassium chlorides, potassium sulfates, and
the like. Non-limiting examples of other inorganic particulate
materials include minerals, fillers, and the like.
[0013] The terms "particle," "particles," "particulate" and similar
terms are used herein to broadly embrace materials having a wide
variety of particle sizes and shapes. As will be apparent to
persons skilled in the art, particle sizes and shapes will depend
on such factors as the particular type of inorganic material as
well as the particular processing technique used (prill,
granulation, etc.). For example, in many granular fertilizers a
majority of particles typically has a mesh size of about 4 to 20,
and a minority of fines often has a mesh size of about 50 to 75.
The terms "particle," "particles," and "particulate" are
particularly inclusive of DSF prills (sometimes also referred to as
"pels"), which typically are processed by dropping molten DSF onto
a moving, cooled, stainless steel belt to form "split pea" shapes.
A majority of the DSF prills usually has a diameter of from about
0.136" to about 0.154" and a height of from about 0.041" to about
0.059".
[0014] Many fertilizers exhibit time-release properties. For
example, when put into soil, some DSF particles disintegrate
immediately, e.g. , within about 30 minutes, while other particles
disintegrate after significantly longer periods of time, e.g., up
to about one year, resulting in a useful time-release of sulfur and
sulfates into the soil. When used with time-release fertilizers,
such as DSF, the anti-dust agents preferably should not interfere
with such disintegration of the fertilizer.
[0015] The anti-dust agent of the present invention comprises at
least one polyhydric alcohol. Preferably, the anti-dust agent is
completely water-soluble and does not require a surfactant. A
preferred polyhydric alcohol is glycerol (C.sub.3H.sub.8O.sub.3,
also referred to as glycerin or glycerine). Examples of other
polyhydric alcohols that can be used include, but are not limited
to, erythritol (C.sub.4H.sub.10O.sub.4); pentaerythritol,
(C.sub.5H.sub.12O.sub.4); and sorbitol, mannitol, and dulcitol (all
C.sub.6H.sub.14O.sub.6) Combinations of any two or more of the
polyhydric alcohols also are useful. The polyhydric alcohols of the
present invention are represented by the formula C.sub.nH
.sub.(2n+2)O.sub.m wherein 3.ltoreq.n.ltoreq.6 and m=n or n-1, with
the proviso that m.gtoreq.3. The polyhydric alcohol can be supplied
in any suitable form. It is preferred that the polyhydric alcohol
has minimal water content, as high water contents can promote
premature disintegration of DSF. Preferably, the water content is
less than about 10 wt %, more preferably less than about 5 wt
%.
[0016] Glycerol is commercially available in pure or substantially
pure form (CAS # 000056-81-5). Glycerol is hygroscopic and will
absorb moisture from the air.
[0017] The anti-dust agent can be applied to the inorganic
particulate material using any suitable technique, such as
spraying. This can be carried out using either a batch or
continuous processing mode, although a continuous process is
preferred for the manufacture of large commercial scale quantities
of inorganic particulate material. For example, the particulate
material can be passed over conveyor belts while the anti-dust
agent is applied via one or more pressurized nozzles.
[0018] The amount of anti-dust agent applied to the inorganic
particulate material should be at least a minimum amount that
provides some reduction in dust formation. There is no particular
maximum amount of anti-dust agent contemplated; the practical
limiting factor is cost. Of course, the anti-dust agent preferably
should not be present in excessive concentrations that may
adversely affect the desired physical and/or chemical properties of
the inorganic particulate material.
[0019] The effective amount of the anti-dust agent also may depend
on the handling and/or packaging of the inorganic particulate
material. For example, lower amounts of the anti-dust agent may be
effective for treatments of fertilizers packaged in bulk bags,
e.g., 2000 or 2500 lb. bags, whereas somewhat larger concentrations
may be required for fertilizers handled in bulk loads.
[0020] It has been found that when using glycerol as an anti-dust
agent for DSF, a minimum dust reducing effective amount is about
0.2 wt % glycerol, based on the total weight of the coated DSF
particles. Preferably, the concentration of glycerol is from about
0.2 wt % to about 2 wt %, more preferably from about 0.25 wt % to
about 1 wt %. The latter range corresponds to applying about 0.5 to
about 2 gallons of glycerol per ton of DSF. Glycerol has a relative
density of 1.2611 kg/L at 20 .degree. C.
[0021] The inorganic particulate material can be prepared using any
suitable technique. During manufacturing of disintegrating sulfur
fertilizer (DSF), for example, molten sulfur fertilizer typically
is dropped onto a moving, cooled, stainless steel belt to form
small split pea shaped prills. The prills typically have a diameter
of from about 0.1 36" to about 0.1 54" and a height of from about
0.041" to about 0.059" . It should be understood that the
particular technique used to prepare the inorganic particulate
material forms no part of the present invention.
[0022] The inorganic particulate material optionally can be blended
with other materials, such as other fertilizer materials, either
prior or subsequent to being treated with the polyhydric alcohol
anti-dust agent. For example, DSF can be treated with glycerol and
then mixed with one or more high-nitrogen fertilizers to prepare a
blended fertilizer. In addition, conventional fertilizer additives
optionally can be added, for example hydrophilic components such as
bentonite clay.
[0023] The efficacy of the anti-dust treatments can be determined
simply by visually observing the coated inorganic particulate
materials during routine handling or transportation. Alternatively,
methods for quantitatively measuring dust liberation from inorganic
particulate materials are described, for example, in U.S. Pat. No.
5,968,222.
EXAMPLES
[0024] The following examples are provided for illustrative
purposes only and should not be construed as limiting the present
invention. The examples illustrate treating disintegrating sulfur
fertilizer (DFS) with glycerol (CAS # 000056-81 -5) as an anti-dust
agent. Glycerol was applied to DSF particles with spray nozzles as
the particles were transported on a conveyor. The application rates
used are indicated in the enumerated examples below.
[0025] Disintegration of the DSF was determined using the following
procedure with the aid of a clean, dry, #30 mesh stainless steel
sieve; a large, clean, dry plastic funnel; large folded fluted
filter paper; an electronic balance capable of weighing to within
0.0001 g; a drying oven at 105.degree. F.; a general balance
capable of weighing 200 g to within 0.1 g; several 500 ml. plastic
beakers; an empty 39 oz. coffee can to hold the funnel; a sink with
a hose containing running cold (approx. 50.degree. F.) water; and a
fine tip permanent marker.
[0026] Using the general balance, a 500 ml. plastic beaker was
weighed, and 100 g of disintegrating sulfur pels were placed in the
beaker. The beaker was filled with cold flowing tap water to 400
ml. The contents were stirred gently and allowed to stand uncovered
for 24 hours. Several pieces of folded fluted filter paper were
marked and weighed on the electronic scale.
[0027] After 24 hours, the #30 sieve was placed on top of the open
end of the 39 oz. coffee can, and the contents of the 500 ml.
plastic beaker were poured into the sieve. The hose was used to
rinse all of the contents of the beaker into the sieve. Immediately
thereafter, the sieve was rinsed with the cold running tap water to
wash the yellow sulfur fines through the sieve. The remaining
sulfur was then washed into one small pile in one quadrant edge of
the #30 sieve.
[0028] The #30 sieve then was removed from the coffee can, and the
coffee can was rinsed until no visible sulfur remained. With the
large plastic funnel placed in the coffee can, the weighed fluted
filter paper was opened and placed into the funnel. The sulfur
remaining on the #30 sieve was carefully washed onto the filter
paper, using as little water as possible. The sieve then was rinsed
with water from the hose to wash any remaining sulfur onto the
filter paper, and water was allowed to flow through the filter
paper for several seconds.
[0029] The filter paper then was carefully removed from the funnel.
After all visible water passed through the filter paper, the filter
paper was placed in the beaker. The beaker containing the filter
paper was placed into the 105.degree. F. oven and allowed to dry
overnight. Each filter paper was removed from the oven, cooled to
room temperature, and weighed on the electronic balance. The
original filter weight then was subtracted to determine the weight
of the retained sulfur. The retained sulfur weight then was
subtracted from 100 g to obtain the weight of the sulfur that
passed through the #30 sieve, and expressed as weight percent
disintegrated.
Examples 1-6
[0030] Glycerol was applied as an anti-dust agent to DSF particles
for packaging in 2000 lbs. bulk bags. All of the samples were at
least two weeks old. Table 1 summarizes the percent disintegration
(weight percent passed through #30 sieve) for DSF particles coated
at a variety of rates ranging from about 0.4 to 1.2 gallon per ton
(gpt). Each sample also was analyzed for disintegration prior to
application of glycerol for purposes of comparison.
[0031] No appreciable dust formation was observed in any of the
glycerol-treated samples during routine handling of the DSF
particles. Visible dust formation was observed, however, during
routine handling of the untreated DSF particles. As illustrated in
Table 1, glycerol had no adverse impact on disintegration of the
DSF. In fact, in many cases glycerol was shown to actually improve
disintegration of the DSF particles.
1TABLE 1 Disintegration of Glycerol-Treated and Untreated DSF
Particles Glycerol Filter Filter Paper + Passed Thru #30 Example
(gpt) Paper (g) Retained S (g) Sieve (wt %) 1 1.2075 8.2604 47.3420
60.92 Comp. 1 0 8.1162 56.2701 51.85 2 1.2075 8.0046 40.9564 67.05
Comp. 2 0 8.2230 45.9647 62.26 3 0.8050 7.9107 80.9660 26.94 3A
0.8050 8.1338 69.4000 38.73 Comp. 3 0 8.2004 78.2180 29.98 4 0.4025
8.2582 42.8216 65.44 Comp. 4 0 8.0890 42.3462 65.74 5 0.4025 8.3682
51.6524 56.72 5A 0.8050 8.0306 53.8239 54.21 Comp. 5 0 8.1357
47.9164 60.22 6 0.4025 8.1456 64.6120 43.53 6A 1.2075 7.9765
51.0784 56.90 Comp. 6 0 7.9983 65.0780 42.92
Example 7
[0032] This example illustrates treating bulk loads of
disintegrating sulfur fertilizer (DFS) with glycerol as an
anti-dust agent. DSF particles were transported on a conveyor past
spray nozzles applying glycerol at a concentration of 1.2 gallons
per ton of DSF (about 0.6 wt %). The coated particles were stored
in bins and later handled using a backhoe. No appreciable dust
formation was observed. The anti-dust agent had no adverse impact
on disintegration of the DSF.
Example 8
[0033] Glycerol was applied to bulk loads of DSF as in Example 7
except that the amount of glycerol was reduced to 0.6 gallons per
ton of DSF (about 0.3 wt %). Glycerol was found to be an effective
anti-dust agent and did not interfere with disintegration.
[0034] While particular embodiments of the present invention have
been described and illustrated, it should be understood that the
invention is not limited thereto since modifications may be made by
persons skilled in the art. The present application contemplates
any and all modifications that fall within the spirit and scope of
the underlying invention disclosed and claimed herein.
* * * * *