CA1333224C - Fertilizer impregnated with liquid agricultural treatment compositions, and method of impregnation - Google Patents
Fertilizer impregnated with liquid agricultural treatment compositions, and method of impregnationInfo
- Publication number
- CA1333224C CA1333224C CA000584340A CA584340A CA1333224C CA 1333224 C CA1333224 C CA 1333224C CA 000584340 A CA000584340 A CA 000584340A CA 584340 A CA584340 A CA 584340A CA 1333224 C CA1333224 C CA 1333224C
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- CA
- Canada
- Prior art keywords
- fertilizer
- herbicide
- tonne
- liters
- flowing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
- C05G3/60—Biocides or preservatives, e.g. disinfectants, pesticides or herbicides; Pest repellants or attractants
Abstract
A free-flowing fertilizer composition composed of a fertilizer impregnated with a herbicide in an amount greater than about 23.5 liters/tonne. A method for impregnating a fertilizer with a herbicide which involves impregnating said fertilizer with the herbicide in an amount of greater than about 23.5 liters/tonne, wherein said fertilizer remains sufficiently free-flowing for application by conventional fertilizer application means.
Description
~ hIzER IHPREGNATED WIl~I
LIQUID AGRICULl~RAL T~F.Al~T CO~POSITIONS, AND ~ETHOD OF IMPREGNATION
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates to processes for impregnating a fertilizer with liquid agricultural treatment compositions, and to fertilizers impregnated with liquid agricultural treatment compositions. More specifically, the present invention relates to the impregnation of a fertilizer with previously unat~ainable amounts of a liquid agricultural treatment compositions, such as an herbicides, the resulting herbicide-impregnated fertilizer.
LIQUID AGRICULl~RAL T~F.Al~T CO~POSITIONS, AND ~ETHOD OF IMPREGNATION
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates to processes for impregnating a fertilizer with liquid agricultural treatment compositions, and to fertilizers impregnated with liquid agricultural treatment compositions. More specifically, the present invention relates to the impregnation of a fertilizer with previously unat~ainable amounts of a liquid agricultural treatment compositions, such as an herbicides, the resulting herbicide-impregnated fertilizer.
2. Description of Background and Material Inf~rmation The concept of impregnating dry bulk fertilizers with herbicides has been known for a number of years. The use of impregnated fertilizers is popular with farmers because it permits the application of both nutrients and herbicides in ~ one application, commonly referred to as "weed and feed"
applications. Although urea, crystalline byproduct of ammonium sulfate and NPK blends have been impregnated with a variety of different herbicides, with varying degrees of success, the present invention is based on the discovery that granular ammonium sulfate is particularly amenable to impregnation with herbicides and the like in amounts in excess of what has heretofore been possible with the previously mentioned impregnated-fertilizers, and yet remains free-flowing.
By way of background, ammonium sulfate has a number of important applications, with perhaps the chief among these being agricultural fertilization. In this capacity ammonium sulfate provides a ready source of nitrogen and sulfur, 13~322~
which are critical crop nutrient6.
Ammonium 6ulfate may be produced in a number of ways, including as a by-product of other industries. For example, ammonium sulfate is commonly crystallized from solutions produced as a by-product from coke ovens and caprolactum plants. The production of ammonium sulfate per se, rather than as an incidental by-product, generally involves combining ammonia with sulfuric acid, which results in ammonium 6ulfate having a crystalline structure.
Ammonium sulfate is often not used as a fertilizer by itself, but rather in combination with other vital plant nutrients. Therefore, in commercial use ammonium sulfate must often be blended with granular fertilizers to produce a balanced fertilizer blend.
There i6 a long history of processes for the production of ammonium sulfate, and of attempts to improve on the shape, 6ize, uniformity, and storage characteristics of ammonium sulfate either by modification of crystallization procedures or by the use of granulating techniques.
A representative example of a conventional method of granulation, is to use a rotary ammoniator granulator.
Another common method is to use a pugmill to contact recycle fines with varying proportions of ammonia and sulphuric acid, using granulation aids such as phosphates, ammonium nitrate, urea, or lignosulfates.
More recently, a process for the production of granular ammonium sulfate has been developed in which ammonium sulfate is granulated in the presence of a granulation aid which i8 an aluminum salt or a ferric salt. In this process, ammonia and sulfuric acid are first mixed in a pipe reactor to form a slurry. The slurry is distributed onto a bed of ammonium sulfate fines, where further ammoniation occurs, and is then granulated in the presence of the aluminum salt or the ferric salt. The resulting product is free-flowing and non-caking; has a pH of about 4.0 to 4.5, measured in a 10% 601ution (by weight in water); and has an average Pfizer hardness (as defined below) of about 5.0 pounds. The granulation may be carried out in a conventional apparatus, ~uch a6 a rotary granulator or a pugmill.
It ha6 been found, however, that ammonium sulfate granules, produced to have a Pfizer hardness of greater than about 5.0 pounds, and preferably greater than about 6.8 pounds, and more preferably at least about 9.8 pounds, with a usual hardness range of between about 9.8 ~nd 12.7 pounds, and having a pH of less than about 4.0, preferably a pH of between about 2.5 and 4.0, and more preferably a pH between about 2.5 and 2.9, with a most preferred average pH of about 2.7, have a 6uperior capacity for the absorption of agricultural treatment composition, 6uch as herbicides and the like, and yet maintain their free-flowing, non-caking characteri6tics rendering such impregnated-fertilizers particularly suitable for use in agricultural "weed and feed" applications.
SUMMARY OF THE INVENTION
The present invention is based on the discovery that granular ammonium sulfate produced by a process which result with free-flowing granules having minimal tendencies to become wet or glisten and cake possess superior absorptive properties when compared to granular urea or conventional crystalline ammonium sulfate. This is particularly true for ammonium sulfate granules produced to have a Pfizer hardness of greater than about 5.0 pounds, and preferably greater than about 6.8 pounds, and most preferably at least about 9.8 pounds, with a usual hardness range of between about 9.8 and 12.7 pounds, as well as for ammonium sulfate granules produce to have a pH of less than about 4.0, and preferably between about 2.5 and 4.0, and most preferably between about 2.5 and 2.9, with an average pH of about 2.7.
It has been unexpectedly discovered that granular ammonium sulfate exhibiting the previously mentioned characteristics remains substantially dry and free-flowing 133322~
when impregnated with ~mount~ of herbicide which would tend to cause urea granule6, crystalline byproduct ammonlum sulfate, and other fertilizers, to become wet, i.e., or gli~ten, and viscous, and tend to agglomerate into ~mall groups that which tend not to be readily flowable.
Herbicide~ which may be u6ed for purposes of the present invention may be eelected from the group consi~ting of Avadex BW (triallate) Edge EC~ (ethafluralin), EPTC,* EPTC
plu6 R-2S788 plu~ R-33865, Butylate*, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, triallate, trifluralin, glysophate, glysophate +2,4-D, sethoxydim, metolachlor, metolachlor + atrazine; S-propyl dipropylthiocarbamate, alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine; S-ethyl lS diisobutylthiocarbamate; 2,6-dichlorobenzonitrile; 1,1'-dimethyl-4-4'-bipyridinium dichloride; 2,4-dichlorophenoxy acetic acid; sodium 2,4-dichlorophenoxy acetate; 3-amino-2,5-dichlorobenzoate; s-ethyl dipropylthiocarbamate; S-ethyl hexahydro-lH-azepine-l-carbothioate; S-ethyl cyclohexyl ethyl thiocarbamate: 2,4,5-trichlorophenoxyacetic acid; 2-methyl-4-chlorophenoxy acetic ac$d; 2,4-bis(3-methoxypropylamino)-6-methylthio-s-triazine; 2-chloro-4-ethylamino-6-isopropylamino-6-triazine; 2-ethylamino-4-i~opropylamino-6-methylmercapto-6-triazine; 3-(3,4-dichloro-phyenyl)-l,l-dimethylurea; N,N-diallyl-alphachloroacetamide;
N-(alpha-chloroacetyl)hexamethyleneimine; N,N-diethyl-alpha-bromoacetamide; 3-amino-2,5-dichloro-benzoic acid and mixtures thereof. Of the previously listed herbicides, liquid fertilizers and emul~ifiable herbicide concentrates selected from the group consisting of Avadex BW (triallate) Edge EC (ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, atrazine and 2,4,-D, are preferred, with Avadex BW and Edge EC being more preferred.
A preferred fertilizer for purposes of impregnation *trade-mark ' ';
133322 i P5947SOl with herbicides in accordance with the present invention iB
free-flowing granular ammonium sulfate. AB used herein granular ammonium sulfate or ammonium sulfate granule6 means particles formed from agglomerated microscopic cry6tals of ammonium sulfate, a6 distinguished from the macroscopic crystals of conventional crystalline ammonium sulfate which are discrete forms vi6ible to the naked eye. Ammonium sulfate granules suitable for purpose6 of the pre6ent invention are produced by a process which involves the steps of adding a granulating aid selected from the group ~ consi6ting of a metal salt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulfuric acid and granulating the slurry to produce ammonium sulfate granules under 6ufficiently acidic conditions that the ammonium sulfate granules have a pH of less than about 4.0, e.g., between about 2.5 and 4Ø
Another free-flowing granular ammonium sulfate preferred for being impregnating with herbicides in accordance with the present invention is produced by a process which involves the 6teps of adding a granulating aid 6elected from the group con6isting of a metal salt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulfuric acid, in an amount sufficient to yield ammonium sulfate granules comprising more than about 0.05 percent by weight of the metal; and granulating the slurry to produce ammonium sulfate granules under sufficiently acidic conditions that the ammonium sulfate granules have a pH of les6 than about 4Ø
Granular ammonium 6ulfate or ammonium sulfate granules preferred for impregnation with herbicides in accordance with the present invention may also be produced by a process which involves the 6teps of adding a granulating aid selected from the group con6i6ting of a metal 6alt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulfuric acid, in an amount 6ufficient to yield ammonium 6ulfate granules compri6ing more than about 0.0 133322~
percent by weight of the metal; granulating the 61urry to produce ammonium sulfate granules under sufficiently acidic conditions that the ammonium sulfate granules have a pH of le6s than about 4.0; followed by cooling the ammonium sulfate granules to a temperature of less than about 150 F
at a cooling rate of greater than about 7.5 F/minute, whereby more than about 85.7% of the ammonium 6ulfate granules have a particle 6ize which equals or exceeds +10 Tyler mesh screen size and the ammonium sulfate granules have a Pfizer hardness of greater than about 5.0 pounds.
An object of the present invention is the production of substantially dry, free-flowing, non-caking ammonium sulfate granules impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, such as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another still further object of the present invention is the production of free-flowing, non-caking ammonium sulfate granules having a pH of between about 2.S and 4.0, including a metal selected from the group consi6ting of aluminum and iron which are impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, such as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another further object of the present invention i8 the production of ammonium sulfate granules having a pH of less than about 4.0, containing more than about 0.05% by weight of a metal selected from the group consi6ting of aluminum and iron which ~re impregnated with herbicides in amount6 up to about 60 liter6/tonne and preferably greater than about 23.5 liters/tonne, 6uch as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and 13~3224 even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another still further ob~ect of the present invention i8 the production of ammonium ~ulfate granule6 having a Pfizer hardnes6 of greater than about 6.8 pounds which are impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, 6uch as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another yet still further object of the present invention i6 the production of ammonium sulfate granules, the production of and wherein more than about 85.7% of the granules are equal to or larger than +10 Tyler mesh 6creen size, which are impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, such a6 amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
It i8 another ob;ect of the present invention to provide a method for impregnating a fertilizer with a liquid agricultural treatment composition selected from the group consisting of herbicides, pesticides, insecticides, fungicides, 6poricides, hematocides, bacteriocides, larvacides and mixtures thereof, which involves impregnating the fertilizer with the liquid agricultural treatment composition in amounts up to about 60 liter6/tonne and preferably greater than about 23.5 liters/tonne, 6uch as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne, wherein the fertilizer remains sufficiently dry and free-flowing for application by conventional fertilizer application means.
1~33224 P5947SOl DESCRIPTION OF PREFERRED EMBODIMENTS
For purposes of the pre6ent invention, the process will be de6cribed with re6pect to the granular ~mmonium sulfate a6 the preferred fertilizer and Avadex BW or Edge EC a8 the herbicide.
The proces6 ~ccording to the present invention initially involve6 the provi6ion of ammonium 6ulfate granules. Granular ammonium sulfate which has been discovered to be suitable for impregnation with herbicides, such as Avadex BW and Edge EC, in accordance with the present invention are produced by a process which involves first forming an ammonium sulfate slurry by mixing ammonia and sulfuric acid in a pipe reactor. The ammonium sulfate 61urry i6 introduced onto a bed of recycled ammonium sulfate fines, where further ammoniation takes place. Granulation is then carried out in the presence of a granulating aid, and the resulting product is dried, 6creened, and cooled.
Any conventional granulating 6ystem may be used, including rotary granulators and pugmills.
The granulating aid may be a metal oxide, preferably hydrated, such as aluminum oxide; a salt of a metal hydroxide, 6uch as 60dium aluminate; an aluminum salt; or a ferric salt. Aluminum salts are preferred, with aluminum sulfate being most preferred. Where the granulating aid contain6 aluminum, the aluminum should be present in a 601uble form.
The aluminum oxide granulating aid i6 preferably u6ed in the form of a 61urry, while the aluminum or ferric salt may conveniently be introduced to the ammonium sulfate slurry in the form of an aqueous solution. Generally, the aqueous solution is introduced into the slurry in the pipe reactor. However, the aqueous solution may be metered into the granulation apparatus at any convenient location, 6uch as adjacent the inlet thereof. Alternatively, the aluminum or ferric salt may be added to the granulator or to the recycle in 601id form, by means of a feeding apparatus.
133322~
Where an aluminum salt iB used, it is generally used in an amount sufficient to give ~ final product containing more than about 0.05% by weight of aluminum. Preferably the product contains between about 0.05 and 1.06% by weight of aluminum, even more preferably between about 0.15 and 1.06%, and most preferably the aluminum content is between about 0.25 ~nd 0.40% by weight.
The product may contain phosphate derived from the starting materials or phosphate may be deliberately added.
The presence of phosphate may favorably affect the granulation of the ammonium sulfate.
The process according to the present invention i6 conducted at a pH sufficient to yield ammonium sulfate granules with a pH of less than about 4.0, measured in a 10%
solution, and the pH may be as low a~ about 2.5.
Granules produced according to the present invention and exhibiting a pH of between about 2.5 and 4.0 show no caking during storage, as initially indicated by performing accelerated caking tests on such granules. 100 gram samples of granular ammonium sulfate were placed in a stainless steel tube with an outer diameter of 2.0 inches. The samples were pressurized to 35 psi, using a pneumatic piston, and stored for one week at a temperature of 85F.
The amples were then removed from the stainless steel tube and examined for caking; no caking was observed.
The accelerated caking tests were confirmed by a series of full-scale production runs producing ammonium sulfate granules having ph values of from 2.5-4Ø The granules were cooled in accordance with the present invention and stored in commercial-sized storage piles of 400-10,000 tons.
After several weeks of ~torage, the product remained free-flowing and free from caking.
After leaving the drying step the granules are screened and cooled prior to storage. Without being bound by this theory, it is thought that the non-caking properties of the low pH granules result from the rapid cooling of the granules, ~uch as in a rotary cooler, generally from an lnitial temperature of about 225F to a pre-storage temperature of about 120F.
The rate of cooling i8 generally greater than about 7.5 F/minute, preferably between about 9.5 and 16.5 F/minute, and most preferably between about 9.5 and 11.5 F/minute.
While the cooling should be rapid, any suitable means may be employed, including but not limited to a rotary cooler or a fluidized bed cooler. The critical factor i6 not how the granules are cooled, but rather that they be cooled to a pre-storage temperature of less than about 150 F and preferably of between about 60 and 130 F, with a pre-storage temperature of between about 110 and 130 F being most preferred.
Granulated ammonium 6ulfate produced according to this process remains free-flowing and doe6 not consolidate or 6et to a hard mass upon being allowed to stand in large piles during storage. In addition, the resulting ammonium 6ulfate granules are 6ubstantially harder than granular ammonium sulfate known to the prior art.
The hardnes6 of the granules is mea6ured with a commercial compression tester, such as a Chatillon compression tester. At least 25 granules within the Tyler mesh size range of -7 +8 from a given product run are tested individually, and the average of these mea6urements is taken a6 the Pfizer hardnes6 of the product run from which the tested granules were taken. The granules are placed, one at a time, on a flat surface provided on the compression tester. Pressure iB applied to each granule using a flat-end rod attached to the compression tester, and a gauge mounted in the compression te6ter measures the pressure reguired to fracture the granule. Ammonium sulfate granules produced according to the process of the present invention generally po6se6s a Pfizer hardne6s in the range of from 9.8 to 12.7 pounds, while prior art granular ammonium sulfate has typical Pfizer hardness values of 5 pounds or less.
Due to the superior 6ize and hardness of the granule6, ammonium ~ulfate produced according to the present invention experiences minimal breakdown into undesirably 6mall fragments during cooling, storage, handling, blending, shipping, and 6preading.
Moreover, use of granular ammonium 6ulfate produced according to the present invention, either as a fertilizer per ~e or as an ingredient in fertilizer blends, produces exceptionally uniform results. This follows from the fact that the mechanics of spreading fertilizer are improved by use of a physically more uniform product, resulting in more uniform spreading. In addition, when fertilizer blends are used, blends using granular ammonium ~ulfate produced according to the present invention will remain uniformly blended, rather than tending to layer out by component by the time the end user is reached as is often the case with prior art blends.
It should be noted that in the process according to the present invention, ammonium sulfate fines produced therein are recycled through the granulation apparatus, where they are formed into the bed onto which the slurry containing ammonium sulfate is distributed. While the recycle ratio generally ranges from about 7:1 to 20:1, ratios as low as about 2.5:1 have been achieved.
In accordance with the best mode for practicing the present invention, the granular ammonium sulfate, exhibiting one or more of the previously discussed characteristics, produced in accordance with the procedures described above, is then impregnated with a herbicide. In this regard, any conventional procedure for impregnating fertilizers with adjuvants, additives and the like, such as agricultural treatment compositions, i.e., herbicides, pesticides, insecticides, fungicides, bacteriocides, sporicides, larvacides, hematocides and mixtures thereof, may be used for purposes of the present invention.
- al -For example, fertilizer, ~uch a6 granular ammonium sulfate may be introduced batchwise into a rotary drum mixer, having a capacity of about 2 to 8 tonne6. The herbicide, 6uch a6 Avadex BW or Edge EC, is then 6prayed slowly into the rotating drum via a metering pump and a 6pray nozzle or nozzle6 until the de6ired ratio of herbicide to fertilizer is reached. In this regard, it has been unexpectedly discovered that granular ammonium sulfate, exhibiting the characteri6tic6 described above, and produced in accordance with the previously described procedure, absorb greater amount6 of herbicide than conventional fertilizer6, such as granular urea or crystalline by product of ammonium sulfate, i.e., amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, e.g., amounts greater than about 28.5 liters/tonne, including amount6 greater than about 30 liter6/tonne, as well a6 ~mount6 greater than about 40 liter6/tonne. Even more unexpected i6 that granular ammonium 6ulfate can absorb amount6 greater than about 50 liters/tonne, i.e., an amount of about 60 liters/tonne, without experiencing the adverse effects normally resulting from impregnation of fertilizer6 with herbicide6. Once the amount of herbicide has been introduced, the herbicide flow i6 then 6topped, and the drum i6 rotated for a few more minutes to ensure that all the herbicide has been absorbed.
The impregnated fertilizer is then discharged from the drum.
Of the previously identified agricultural treatment compositions which may be suitable for purposes of the present invention, herbicides have been found to be preferred for purposes of impregnating granular ammonium sulfate in accordance with the present invention. Such herbicides include those selected from the group consisting of Avadex BW, Edge EC, EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, triallate, trifluralin, glysophate, glysophate +2,4-D, 6ethoxydim, metolachlor, metolachlor + atrazine; S-propyl dipropylthiocarbamate, alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine: S-ethyl diisobutylthiocarbamate; 2,6-dichlorobenzonitrile; 1,1'-dimethyl-4-4'-bipyridinium dichloride; 2,4-dichlorophenoxy acetic acid; sodium 2,4-dichlorophenoxy acetate; 3-amino-2,5-dichlorobenzoate; s-ethyl dipropylthiocarbamate; S-ethyl hexahydro-lH-azepine-l-carbothioate; S-ethyl cyclohexyl ethyl thiocarbamate; 2,4,5-trichlorophenoxyacetic acid; 2-methyl-4-chlorophenoxy acetic acid; 2,4-bis(3-methoxypropylamino)-6-methylthio-s-triazine; 2-chloro-4-ethylamino-6-isopropylamino-s-triazine; 2-ethylamino-4-isopropylamino-6-methylmercapto-s-triazine; 3-(3,4-dichlorophyenyl)-l,l-dimethylurea; N,N-diallyl-alpha-chloroacetamide; N-(alpha-chloroacetyl)hexamethyleneimine;
N,N-diethyl-alpha-bromoacetamide; 3-amino-2,5-dichloro-benzoic acid and mixtures thereof. Of the previously li6ted herbicides, liquid herbicides and emulsifiable herbicide concentrates, such as those selected from the group consi6ting of Avadex BW (triallate) Edge EC
(ethafluralin), EPTC, EPTC plUB R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, atrazine and 2,4,-D, are preferred, with Avadex BW and Edge EC being more preferred.
The present invention may be further appreciated by reference to the following Examples. It is to be understood that these Examples are merely illustrative and in no way define or limit the scope of the present invention, which extends to any and all composition6, means, and methods suited for practice of the process according to the present invention, as well as to any and all products made thereby.
EXAMPLE I
Approximately four hundred grams of fertilizer was placed in a one liter polyethylene sample bottle.
Approximately one third of the appropriate amount of emulsifiable herbicide, i.e., Avadex BW, was added to the 133322~
P5947SOl fertilizer and the sample bottle wa~ agitated by hand forapproximately one minute. Then, the next third of the appropriate volume of herbicide was added, followed by about one minute of agitation: prior to finally adding the last third of the herbicide followed by about one to two minutes of agitation. The reFulting mixture was then transferred to 125 ml glass sample bottles.
After all the 6amples were prepared, each sample was compared qualitatively. The samples sat in the bottles for-about one to two hours before the comparisons took place.
(Avadex ~.W. is a registered trademark of Monsanto Company).
The test results are shown in Tables 1 and 2 appearing below:
133322~
APPEARANCE OF GRANULAR FERTILIZERS AFTER
IMPREGNATION WITH HERBICIDE
Granular Ammonium Sulphate 20.5-0-0-24 IMPREGNATION RATE
(LITERS HERBICIDE/TONNE FERTILIZER) OBSERVATIONS
23.5 Granules are dry with no visible moisture on 6urface. Granules are free flowing.
28.5 Granules are dry with no visible moisture on 6urface. Granules are free flowing.
36.9 Surface of some granules slightly moist. Granules do not stick together and remain free flowing.
47.0 Surface of all granules are wet.
Granules begin to adhere to each other. Still relatively free flowing.
58.7 Surfaces of all granules are wet. Granules adhere together in small clu~ters of 3 or more. Flow becomes vi6cous, but still 133322~
P5947SOl relatlvely froe flowing.
TABLE ~
SAPPEARANCE OF GRANULAR FERTILIZERS AFTER
IMPREGNATION WITH AVADES (REGISTERED) BW HERBICIDE
Urea 46-0-0 IMPREGNATION RATE OBSERVATIONS
(LITERS HERBICIDE/TONNE FERTILIZER) ONE HOUR AFTER BLENDING
23.5 Surfaces of all granules are wet. Granules adhere together in small clusters of 3 or more.
Flow is viscous, but 8till relatively free flowing.
Similar in appearance to granular ammonium sulphate with 58.7 liters herbicide/tonne fertilizer.
36.9 Surfaces of all granules are very wet. Granules adhere together in clusters. Flow is more viscous than urea with 23.5 l/tne.
Byproduct Crystalline Ammonium Sulphate 23.5 Surfaces of all granules are very wet. Granules adhere together in cluster6. Flow is viscou6.
36.9 Surfaces of all granules are wetter than crystalline with 23.5 l/tne. Granules adhere together in clusters. Flow is more viscou6 than crystalline with 23.5 l/tne.
As shown, the granular ammonium sulphate impregnated with Avadex in accordance with the present invention was found to remain dry and flowable at impregnation rates up to about 37 liters of herbicide per tonne of fertilizer. At rates above this, the surface of the granules began to become wet, granules began to agglomerate and the mixture became viscous, and yet the granules still remain substantially free-flowing.
In contrast, the urea mixture was wet at impregnation rates as low as 23.5 liters of herbicide per tonne of urea with some agglomeration and increase in viscosity. The agglomeration and viscosity was more pronounced at 37 liters/tonne impregnation rate. The crystalline byproduct ammonium 6ulphate was very wet and vi6cou6 with a high degree of agglomeration at both tested impregnation rates.
Thus, the granular ammonium sulphate impregnated with Avadex herbicide in accordance with the present invention exhibited a a much greater capacity for absorbing herbicide than did urea or crystalline byproduct ammonium 6ulphate.
At about 23.5 l/tne, to ~u6t under 36.9 l/tne, the granular 133322~
ammonium ~ulphate impregnated with the herbicide inaccordance with the pre6ent invention was relatively dry, versus urea and crystalline ammonium, both of which exhibited excessive moi6ture at impregnation rates as low as 23.5 l/tne. At impregnation rates of about 58.7 l/tne, the granular ammonium sulpl.ate impregnated with the herbicide in accordance with the present invention exhibited properties similar to those of urea impregnated with ~ust 23.5 l/tne.
EXAMPLE II
Using a procedure 6imilar to the one described above with respect to Example I, a similar test wa6 conducted wherein Edge EC, which i8 ethafluralin dissolved in an organic solvent, was used as the herbicide for purpo6es of impregnating the fertilizer.
Approximately 400 grams of fertilizer was placed in a one liter polyethylene 6ample bottle. Approximately one third of the appropriate amount of liquid herbicide, in this case Edge EC, was added to the fertillzer and the sample bottle was agitated by hand for approximately one minute.
Afterwards, the next third of the appropriate volume of herbicide was added to the bottle followed by agitating the bottle containing the fertilizer and herbicide mixture for about one minute. Finally, the last third of the appropriate volume of herbicide was added to the bottle which was then agitated between about one-two minutes.
Afterwards, the resulting mixture was transferred to 125 ml.
glass sample bottles, which were permitted to sit for about one-two hours. Subsequently, the samples were compared qualitatively, the test results being shown in Table 3 appearing below.
GRANULAR AMMONIUM SULPHATE
S EDGE ABSORPTION CAPACITY
ABSORPTION CAPACITY
(LITERS OF EDGE/TONNE FERTILIZER) OBSERVATIONS AFTER 1-2 HOURS
AMMONIUM SULPHATE UREA
15 15.7 DRY, FREE FLOWING
23.6DRY, FREE FLOWING
31.4 10.0 SLIGHT MOISTURE, FREE FLOWING
39.3 15.7 WET, STICKY, FREE FLOWING
50.0 23.6 WET, CLUSTERS, VISCOUS FLOW
31.4 VERY WET, CLUSTERS, VISCOUS FLOW
As indicated above, granular ammonium 6ulfate can be impregnated with Edge EC with similar re6ults to that achieved when granular ammonium sulfate i6 impregnated with Avadex BW. In this regard, granular ammonium sulfate ab60rbed Edge EC in the amount of 23.6 liters/tonne of fertilizer, and yet the impregnated granular ammonium sulfate remained dry and free-flowing. In contrast, granulated urea formed clusters, glistened or appeared wet and exhibited a viscous flow when impregnated with 23.6 liters of Edge EC/tonne of fertilizer. This condition did not begin to appear in granular ammonium sulphate until impregnated with 50 liter6 of Edge EC/tonne of fertilizer.
As used herein, dry or substantially dry refer6 to the appearance of fertilizer, such a6 granular ammonium 6ulfate, which is different from fertilizers which appear wet or 133322~
glisten upon impregnation with an amount of herbicide. The term dry, therefore, is not used in the strict sense of being bone dry, nor is the term meant to be limited to a prescribed moisture or liquid content. A simple determination of whether a fertilizer i6 wet or dry can be made by placing a quantity of impregnated ammonium sulfate granules in a glass-sided vessel and observing whether the particles glisten and the sides of the glass become wet.
Although the invention has been described with respect to the preferred embodiments di~cussed above, it is clearly understood that this is by way of example only, and that the invention is not limited to the particulars disclosed but extends to all eguivalents within the scope of the claims.
applications. Although urea, crystalline byproduct of ammonium sulfate and NPK blends have been impregnated with a variety of different herbicides, with varying degrees of success, the present invention is based on the discovery that granular ammonium sulfate is particularly amenable to impregnation with herbicides and the like in amounts in excess of what has heretofore been possible with the previously mentioned impregnated-fertilizers, and yet remains free-flowing.
By way of background, ammonium sulfate has a number of important applications, with perhaps the chief among these being agricultural fertilization. In this capacity ammonium sulfate provides a ready source of nitrogen and sulfur, 13~322~
which are critical crop nutrient6.
Ammonium 6ulfate may be produced in a number of ways, including as a by-product of other industries. For example, ammonium sulfate is commonly crystallized from solutions produced as a by-product from coke ovens and caprolactum plants. The production of ammonium sulfate per se, rather than as an incidental by-product, generally involves combining ammonia with sulfuric acid, which results in ammonium 6ulfate having a crystalline structure.
Ammonium sulfate is often not used as a fertilizer by itself, but rather in combination with other vital plant nutrients. Therefore, in commercial use ammonium sulfate must often be blended with granular fertilizers to produce a balanced fertilizer blend.
There i6 a long history of processes for the production of ammonium sulfate, and of attempts to improve on the shape, 6ize, uniformity, and storage characteristics of ammonium sulfate either by modification of crystallization procedures or by the use of granulating techniques.
A representative example of a conventional method of granulation, is to use a rotary ammoniator granulator.
Another common method is to use a pugmill to contact recycle fines with varying proportions of ammonia and sulphuric acid, using granulation aids such as phosphates, ammonium nitrate, urea, or lignosulfates.
More recently, a process for the production of granular ammonium sulfate has been developed in which ammonium sulfate is granulated in the presence of a granulation aid which i8 an aluminum salt or a ferric salt. In this process, ammonia and sulfuric acid are first mixed in a pipe reactor to form a slurry. The slurry is distributed onto a bed of ammonium sulfate fines, where further ammoniation occurs, and is then granulated in the presence of the aluminum salt or the ferric salt. The resulting product is free-flowing and non-caking; has a pH of about 4.0 to 4.5, measured in a 10% 601ution (by weight in water); and has an average Pfizer hardness (as defined below) of about 5.0 pounds. The granulation may be carried out in a conventional apparatus, ~uch a6 a rotary granulator or a pugmill.
It ha6 been found, however, that ammonium sulfate granules, produced to have a Pfizer hardness of greater than about 5.0 pounds, and preferably greater than about 6.8 pounds, and more preferably at least about 9.8 pounds, with a usual hardness range of between about 9.8 ~nd 12.7 pounds, and having a pH of less than about 4.0, preferably a pH of between about 2.5 and 4.0, and more preferably a pH between about 2.5 and 2.9, with a most preferred average pH of about 2.7, have a 6uperior capacity for the absorption of agricultural treatment composition, 6uch as herbicides and the like, and yet maintain their free-flowing, non-caking characteri6tics rendering such impregnated-fertilizers particularly suitable for use in agricultural "weed and feed" applications.
SUMMARY OF THE INVENTION
The present invention is based on the discovery that granular ammonium sulfate produced by a process which result with free-flowing granules having minimal tendencies to become wet or glisten and cake possess superior absorptive properties when compared to granular urea or conventional crystalline ammonium sulfate. This is particularly true for ammonium sulfate granules produced to have a Pfizer hardness of greater than about 5.0 pounds, and preferably greater than about 6.8 pounds, and most preferably at least about 9.8 pounds, with a usual hardness range of between about 9.8 and 12.7 pounds, as well as for ammonium sulfate granules produce to have a pH of less than about 4.0, and preferably between about 2.5 and 4.0, and most preferably between about 2.5 and 2.9, with an average pH of about 2.7.
It has been unexpectedly discovered that granular ammonium sulfate exhibiting the previously mentioned characteristics remains substantially dry and free-flowing 133322~
when impregnated with ~mount~ of herbicide which would tend to cause urea granule6, crystalline byproduct ammonlum sulfate, and other fertilizers, to become wet, i.e., or gli~ten, and viscous, and tend to agglomerate into ~mall groups that which tend not to be readily flowable.
Herbicide~ which may be u6ed for purposes of the present invention may be eelected from the group consi~ting of Avadex BW (triallate) Edge EC~ (ethafluralin), EPTC,* EPTC
plu6 R-2S788 plu~ R-33865, Butylate*, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, triallate, trifluralin, glysophate, glysophate +2,4-D, sethoxydim, metolachlor, metolachlor + atrazine; S-propyl dipropylthiocarbamate, alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine; S-ethyl lS diisobutylthiocarbamate; 2,6-dichlorobenzonitrile; 1,1'-dimethyl-4-4'-bipyridinium dichloride; 2,4-dichlorophenoxy acetic acid; sodium 2,4-dichlorophenoxy acetate; 3-amino-2,5-dichlorobenzoate; s-ethyl dipropylthiocarbamate; S-ethyl hexahydro-lH-azepine-l-carbothioate; S-ethyl cyclohexyl ethyl thiocarbamate: 2,4,5-trichlorophenoxyacetic acid; 2-methyl-4-chlorophenoxy acetic ac$d; 2,4-bis(3-methoxypropylamino)-6-methylthio-s-triazine; 2-chloro-4-ethylamino-6-isopropylamino-6-triazine; 2-ethylamino-4-i~opropylamino-6-methylmercapto-6-triazine; 3-(3,4-dichloro-phyenyl)-l,l-dimethylurea; N,N-diallyl-alphachloroacetamide;
N-(alpha-chloroacetyl)hexamethyleneimine; N,N-diethyl-alpha-bromoacetamide; 3-amino-2,5-dichloro-benzoic acid and mixtures thereof. Of the previously listed herbicides, liquid fertilizers and emul~ifiable herbicide concentrates selected from the group consisting of Avadex BW (triallate) Edge EC (ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, atrazine and 2,4,-D, are preferred, with Avadex BW and Edge EC being more preferred.
A preferred fertilizer for purposes of impregnation *trade-mark ' ';
133322 i P5947SOl with herbicides in accordance with the present invention iB
free-flowing granular ammonium sulfate. AB used herein granular ammonium sulfate or ammonium sulfate granule6 means particles formed from agglomerated microscopic cry6tals of ammonium sulfate, a6 distinguished from the macroscopic crystals of conventional crystalline ammonium sulfate which are discrete forms vi6ible to the naked eye. Ammonium sulfate granules suitable for purpose6 of the pre6ent invention are produced by a process which involves the steps of adding a granulating aid selected from the group ~ consi6ting of a metal salt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulfuric acid and granulating the slurry to produce ammonium sulfate granules under 6ufficiently acidic conditions that the ammonium sulfate granules have a pH of less than about 4.0, e.g., between about 2.5 and 4Ø
Another free-flowing granular ammonium sulfate preferred for being impregnating with herbicides in accordance with the present invention is produced by a process which involves the 6teps of adding a granulating aid 6elected from the group con6isting of a metal salt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulfuric acid, in an amount sufficient to yield ammonium sulfate granules comprising more than about 0.05 percent by weight of the metal; and granulating the slurry to produce ammonium sulfate granules under sufficiently acidic conditions that the ammonium sulfate granules have a pH of les6 than about 4Ø
Granular ammonium 6ulfate or ammonium sulfate granules preferred for impregnation with herbicides in accordance with the present invention may also be produced by a process which involves the 6teps of adding a granulating aid selected from the group con6i6ting of a metal 6alt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulfuric acid, in an amount 6ufficient to yield ammonium 6ulfate granules compri6ing more than about 0.0 133322~
percent by weight of the metal; granulating the 61urry to produce ammonium sulfate granules under sufficiently acidic conditions that the ammonium sulfate granules have a pH of le6s than about 4.0; followed by cooling the ammonium sulfate granules to a temperature of less than about 150 F
at a cooling rate of greater than about 7.5 F/minute, whereby more than about 85.7% of the ammonium 6ulfate granules have a particle 6ize which equals or exceeds +10 Tyler mesh screen size and the ammonium sulfate granules have a Pfizer hardness of greater than about 5.0 pounds.
An object of the present invention is the production of substantially dry, free-flowing, non-caking ammonium sulfate granules impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, such as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another still further object of the present invention is the production of free-flowing, non-caking ammonium sulfate granules having a pH of between about 2.S and 4.0, including a metal selected from the group consi6ting of aluminum and iron which are impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, such as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another further object of the present invention i8 the production of ammonium sulfate granules having a pH of less than about 4.0, containing more than about 0.05% by weight of a metal selected from the group consi6ting of aluminum and iron which ~re impregnated with herbicides in amount6 up to about 60 liter6/tonne and preferably greater than about 23.5 liters/tonne, 6uch as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and 13~3224 even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another still further ob~ect of the present invention i8 the production of ammonium ~ulfate granule6 having a Pfizer hardnes6 of greater than about 6.8 pounds which are impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, 6uch as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
Another yet still further object of the present invention i6 the production of ammonium sulfate granules, the production of and wherein more than about 85.7% of the granules are equal to or larger than +10 Tyler mesh 6creen size, which are impregnated with herbicides in amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, such a6 amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne.
It i8 another ob;ect of the present invention to provide a method for impregnating a fertilizer with a liquid agricultural treatment composition selected from the group consisting of herbicides, pesticides, insecticides, fungicides, 6poricides, hematocides, bacteriocides, larvacides and mixtures thereof, which involves impregnating the fertilizer with the liquid agricultural treatment composition in amounts up to about 60 liter6/tonne and preferably greater than about 23.5 liters/tonne, 6uch as amounts greater than about 28.5 liters/tonne, i.e., greater than about 30 liters/tonne, and even greater than about 40 liters/tonne, e.g., greater than about 50 liters/tonne, wherein the fertilizer remains sufficiently dry and free-flowing for application by conventional fertilizer application means.
1~33224 P5947SOl DESCRIPTION OF PREFERRED EMBODIMENTS
For purposes of the pre6ent invention, the process will be de6cribed with re6pect to the granular ~mmonium sulfate a6 the preferred fertilizer and Avadex BW or Edge EC a8 the herbicide.
The proces6 ~ccording to the present invention initially involve6 the provi6ion of ammonium 6ulfate granules. Granular ammonium sulfate which has been discovered to be suitable for impregnation with herbicides, such as Avadex BW and Edge EC, in accordance with the present invention are produced by a process which involves first forming an ammonium sulfate slurry by mixing ammonia and sulfuric acid in a pipe reactor. The ammonium sulfate 61urry i6 introduced onto a bed of recycled ammonium sulfate fines, where further ammoniation takes place. Granulation is then carried out in the presence of a granulating aid, and the resulting product is dried, 6creened, and cooled.
Any conventional granulating 6ystem may be used, including rotary granulators and pugmills.
The granulating aid may be a metal oxide, preferably hydrated, such as aluminum oxide; a salt of a metal hydroxide, 6uch as 60dium aluminate; an aluminum salt; or a ferric salt. Aluminum salts are preferred, with aluminum sulfate being most preferred. Where the granulating aid contain6 aluminum, the aluminum should be present in a 601uble form.
The aluminum oxide granulating aid i6 preferably u6ed in the form of a 61urry, while the aluminum or ferric salt may conveniently be introduced to the ammonium sulfate slurry in the form of an aqueous solution. Generally, the aqueous solution is introduced into the slurry in the pipe reactor. However, the aqueous solution may be metered into the granulation apparatus at any convenient location, 6uch as adjacent the inlet thereof. Alternatively, the aluminum or ferric salt may be added to the granulator or to the recycle in 601id form, by means of a feeding apparatus.
133322~
Where an aluminum salt iB used, it is generally used in an amount sufficient to give ~ final product containing more than about 0.05% by weight of aluminum. Preferably the product contains between about 0.05 and 1.06% by weight of aluminum, even more preferably between about 0.15 and 1.06%, and most preferably the aluminum content is between about 0.25 ~nd 0.40% by weight.
The product may contain phosphate derived from the starting materials or phosphate may be deliberately added.
The presence of phosphate may favorably affect the granulation of the ammonium sulfate.
The process according to the present invention i6 conducted at a pH sufficient to yield ammonium sulfate granules with a pH of less than about 4.0, measured in a 10%
solution, and the pH may be as low a~ about 2.5.
Granules produced according to the present invention and exhibiting a pH of between about 2.5 and 4.0 show no caking during storage, as initially indicated by performing accelerated caking tests on such granules. 100 gram samples of granular ammonium sulfate were placed in a stainless steel tube with an outer diameter of 2.0 inches. The samples were pressurized to 35 psi, using a pneumatic piston, and stored for one week at a temperature of 85F.
The amples were then removed from the stainless steel tube and examined for caking; no caking was observed.
The accelerated caking tests were confirmed by a series of full-scale production runs producing ammonium sulfate granules having ph values of from 2.5-4Ø The granules were cooled in accordance with the present invention and stored in commercial-sized storage piles of 400-10,000 tons.
After several weeks of ~torage, the product remained free-flowing and free from caking.
After leaving the drying step the granules are screened and cooled prior to storage. Without being bound by this theory, it is thought that the non-caking properties of the low pH granules result from the rapid cooling of the granules, ~uch as in a rotary cooler, generally from an lnitial temperature of about 225F to a pre-storage temperature of about 120F.
The rate of cooling i8 generally greater than about 7.5 F/minute, preferably between about 9.5 and 16.5 F/minute, and most preferably between about 9.5 and 11.5 F/minute.
While the cooling should be rapid, any suitable means may be employed, including but not limited to a rotary cooler or a fluidized bed cooler. The critical factor i6 not how the granules are cooled, but rather that they be cooled to a pre-storage temperature of less than about 150 F and preferably of between about 60 and 130 F, with a pre-storage temperature of between about 110 and 130 F being most preferred.
Granulated ammonium 6ulfate produced according to this process remains free-flowing and doe6 not consolidate or 6et to a hard mass upon being allowed to stand in large piles during storage. In addition, the resulting ammonium 6ulfate granules are 6ubstantially harder than granular ammonium sulfate known to the prior art.
The hardnes6 of the granules is mea6ured with a commercial compression tester, such as a Chatillon compression tester. At least 25 granules within the Tyler mesh size range of -7 +8 from a given product run are tested individually, and the average of these mea6urements is taken a6 the Pfizer hardnes6 of the product run from which the tested granules were taken. The granules are placed, one at a time, on a flat surface provided on the compression tester. Pressure iB applied to each granule using a flat-end rod attached to the compression tester, and a gauge mounted in the compression te6ter measures the pressure reguired to fracture the granule. Ammonium sulfate granules produced according to the process of the present invention generally po6se6s a Pfizer hardne6s in the range of from 9.8 to 12.7 pounds, while prior art granular ammonium sulfate has typical Pfizer hardness values of 5 pounds or less.
Due to the superior 6ize and hardness of the granule6, ammonium ~ulfate produced according to the present invention experiences minimal breakdown into undesirably 6mall fragments during cooling, storage, handling, blending, shipping, and 6preading.
Moreover, use of granular ammonium 6ulfate produced according to the present invention, either as a fertilizer per ~e or as an ingredient in fertilizer blends, produces exceptionally uniform results. This follows from the fact that the mechanics of spreading fertilizer are improved by use of a physically more uniform product, resulting in more uniform spreading. In addition, when fertilizer blends are used, blends using granular ammonium ~ulfate produced according to the present invention will remain uniformly blended, rather than tending to layer out by component by the time the end user is reached as is often the case with prior art blends.
It should be noted that in the process according to the present invention, ammonium sulfate fines produced therein are recycled through the granulation apparatus, where they are formed into the bed onto which the slurry containing ammonium sulfate is distributed. While the recycle ratio generally ranges from about 7:1 to 20:1, ratios as low as about 2.5:1 have been achieved.
In accordance with the best mode for practicing the present invention, the granular ammonium sulfate, exhibiting one or more of the previously discussed characteristics, produced in accordance with the procedures described above, is then impregnated with a herbicide. In this regard, any conventional procedure for impregnating fertilizers with adjuvants, additives and the like, such as agricultural treatment compositions, i.e., herbicides, pesticides, insecticides, fungicides, bacteriocides, sporicides, larvacides, hematocides and mixtures thereof, may be used for purposes of the present invention.
- al -For example, fertilizer, ~uch a6 granular ammonium sulfate may be introduced batchwise into a rotary drum mixer, having a capacity of about 2 to 8 tonne6. The herbicide, 6uch a6 Avadex BW or Edge EC, is then 6prayed slowly into the rotating drum via a metering pump and a 6pray nozzle or nozzle6 until the de6ired ratio of herbicide to fertilizer is reached. In this regard, it has been unexpectedly discovered that granular ammonium sulfate, exhibiting the characteri6tic6 described above, and produced in accordance with the previously described procedure, absorb greater amount6 of herbicide than conventional fertilizer6, such as granular urea or crystalline by product of ammonium sulfate, i.e., amounts up to about 60 liters/tonne and preferably greater than about 23.5 liters/tonne, e.g., amounts greater than about 28.5 liters/tonne, including amount6 greater than about 30 liter6/tonne, as well a6 ~mount6 greater than about 40 liter6/tonne. Even more unexpected i6 that granular ammonium 6ulfate can absorb amount6 greater than about 50 liters/tonne, i.e., an amount of about 60 liters/tonne, without experiencing the adverse effects normally resulting from impregnation of fertilizer6 with herbicide6. Once the amount of herbicide has been introduced, the herbicide flow i6 then 6topped, and the drum i6 rotated for a few more minutes to ensure that all the herbicide has been absorbed.
The impregnated fertilizer is then discharged from the drum.
Of the previously identified agricultural treatment compositions which may be suitable for purposes of the present invention, herbicides have been found to be preferred for purposes of impregnating granular ammonium sulfate in accordance with the present invention. Such herbicides include those selected from the group consisting of Avadex BW, Edge EC, EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, triallate, trifluralin, glysophate, glysophate +2,4-D, 6ethoxydim, metolachlor, metolachlor + atrazine; S-propyl dipropylthiocarbamate, alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine: S-ethyl diisobutylthiocarbamate; 2,6-dichlorobenzonitrile; 1,1'-dimethyl-4-4'-bipyridinium dichloride; 2,4-dichlorophenoxy acetic acid; sodium 2,4-dichlorophenoxy acetate; 3-amino-2,5-dichlorobenzoate; s-ethyl dipropylthiocarbamate; S-ethyl hexahydro-lH-azepine-l-carbothioate; S-ethyl cyclohexyl ethyl thiocarbamate; 2,4,5-trichlorophenoxyacetic acid; 2-methyl-4-chlorophenoxy acetic acid; 2,4-bis(3-methoxypropylamino)-6-methylthio-s-triazine; 2-chloro-4-ethylamino-6-isopropylamino-s-triazine; 2-ethylamino-4-isopropylamino-6-methylmercapto-s-triazine; 3-(3,4-dichlorophyenyl)-l,l-dimethylurea; N,N-diallyl-alpha-chloroacetamide; N-(alpha-chloroacetyl)hexamethyleneimine;
N,N-diethyl-alpha-bromoacetamide; 3-amino-2,5-dichloro-benzoic acid and mixtures thereof. Of the previously li6ted herbicides, liquid herbicides and emulsifiable herbicide concentrates, such as those selected from the group consi6ting of Avadex BW (triallate) Edge EC
(ethafluralin), EPTC, EPTC plUB R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, atrazine and 2,4,-D, are preferred, with Avadex BW and Edge EC being more preferred.
The present invention may be further appreciated by reference to the following Examples. It is to be understood that these Examples are merely illustrative and in no way define or limit the scope of the present invention, which extends to any and all composition6, means, and methods suited for practice of the process according to the present invention, as well as to any and all products made thereby.
EXAMPLE I
Approximately four hundred grams of fertilizer was placed in a one liter polyethylene sample bottle.
Approximately one third of the appropriate amount of emulsifiable herbicide, i.e., Avadex BW, was added to the 133322~
P5947SOl fertilizer and the sample bottle wa~ agitated by hand forapproximately one minute. Then, the next third of the appropriate volume of herbicide was added, followed by about one minute of agitation: prior to finally adding the last third of the herbicide followed by about one to two minutes of agitation. The reFulting mixture was then transferred to 125 ml glass sample bottles.
After all the 6amples were prepared, each sample was compared qualitatively. The samples sat in the bottles for-about one to two hours before the comparisons took place.
(Avadex ~.W. is a registered trademark of Monsanto Company).
The test results are shown in Tables 1 and 2 appearing below:
133322~
APPEARANCE OF GRANULAR FERTILIZERS AFTER
IMPREGNATION WITH HERBICIDE
Granular Ammonium Sulphate 20.5-0-0-24 IMPREGNATION RATE
(LITERS HERBICIDE/TONNE FERTILIZER) OBSERVATIONS
23.5 Granules are dry with no visible moisture on 6urface. Granules are free flowing.
28.5 Granules are dry with no visible moisture on 6urface. Granules are free flowing.
36.9 Surface of some granules slightly moist. Granules do not stick together and remain free flowing.
47.0 Surface of all granules are wet.
Granules begin to adhere to each other. Still relatively free flowing.
58.7 Surfaces of all granules are wet. Granules adhere together in small clu~ters of 3 or more. Flow becomes vi6cous, but still 133322~
P5947SOl relatlvely froe flowing.
TABLE ~
SAPPEARANCE OF GRANULAR FERTILIZERS AFTER
IMPREGNATION WITH AVADES (REGISTERED) BW HERBICIDE
Urea 46-0-0 IMPREGNATION RATE OBSERVATIONS
(LITERS HERBICIDE/TONNE FERTILIZER) ONE HOUR AFTER BLENDING
23.5 Surfaces of all granules are wet. Granules adhere together in small clusters of 3 or more.
Flow is viscous, but 8till relatively free flowing.
Similar in appearance to granular ammonium sulphate with 58.7 liters herbicide/tonne fertilizer.
36.9 Surfaces of all granules are very wet. Granules adhere together in clusters. Flow is more viscous than urea with 23.5 l/tne.
Byproduct Crystalline Ammonium Sulphate 23.5 Surfaces of all granules are very wet. Granules adhere together in cluster6. Flow is viscou6.
36.9 Surfaces of all granules are wetter than crystalline with 23.5 l/tne. Granules adhere together in clusters. Flow is more viscou6 than crystalline with 23.5 l/tne.
As shown, the granular ammonium sulphate impregnated with Avadex in accordance with the present invention was found to remain dry and flowable at impregnation rates up to about 37 liters of herbicide per tonne of fertilizer. At rates above this, the surface of the granules began to become wet, granules began to agglomerate and the mixture became viscous, and yet the granules still remain substantially free-flowing.
In contrast, the urea mixture was wet at impregnation rates as low as 23.5 liters of herbicide per tonne of urea with some agglomeration and increase in viscosity. The agglomeration and viscosity was more pronounced at 37 liters/tonne impregnation rate. The crystalline byproduct ammonium 6ulphate was very wet and vi6cou6 with a high degree of agglomeration at both tested impregnation rates.
Thus, the granular ammonium sulphate impregnated with Avadex herbicide in accordance with the present invention exhibited a a much greater capacity for absorbing herbicide than did urea or crystalline byproduct ammonium 6ulphate.
At about 23.5 l/tne, to ~u6t under 36.9 l/tne, the granular 133322~
ammonium ~ulphate impregnated with the herbicide inaccordance with the pre6ent invention was relatively dry, versus urea and crystalline ammonium, both of which exhibited excessive moi6ture at impregnation rates as low as 23.5 l/tne. At impregnation rates of about 58.7 l/tne, the granular ammonium sulpl.ate impregnated with the herbicide in accordance with the present invention exhibited properties similar to those of urea impregnated with ~ust 23.5 l/tne.
EXAMPLE II
Using a procedure 6imilar to the one described above with respect to Example I, a similar test wa6 conducted wherein Edge EC, which i8 ethafluralin dissolved in an organic solvent, was used as the herbicide for purpo6es of impregnating the fertilizer.
Approximately 400 grams of fertilizer was placed in a one liter polyethylene 6ample bottle. Approximately one third of the appropriate amount of liquid herbicide, in this case Edge EC, was added to the fertillzer and the sample bottle was agitated by hand for approximately one minute.
Afterwards, the next third of the appropriate volume of herbicide was added to the bottle followed by agitating the bottle containing the fertilizer and herbicide mixture for about one minute. Finally, the last third of the appropriate volume of herbicide was added to the bottle which was then agitated between about one-two minutes.
Afterwards, the resulting mixture was transferred to 125 ml.
glass sample bottles, which were permitted to sit for about one-two hours. Subsequently, the samples were compared qualitatively, the test results being shown in Table 3 appearing below.
GRANULAR AMMONIUM SULPHATE
S EDGE ABSORPTION CAPACITY
ABSORPTION CAPACITY
(LITERS OF EDGE/TONNE FERTILIZER) OBSERVATIONS AFTER 1-2 HOURS
AMMONIUM SULPHATE UREA
15 15.7 DRY, FREE FLOWING
23.6DRY, FREE FLOWING
31.4 10.0 SLIGHT MOISTURE, FREE FLOWING
39.3 15.7 WET, STICKY, FREE FLOWING
50.0 23.6 WET, CLUSTERS, VISCOUS FLOW
31.4 VERY WET, CLUSTERS, VISCOUS FLOW
As indicated above, granular ammonium 6ulfate can be impregnated with Edge EC with similar re6ults to that achieved when granular ammonium sulfate i6 impregnated with Avadex BW. In this regard, granular ammonium sulfate ab60rbed Edge EC in the amount of 23.6 liters/tonne of fertilizer, and yet the impregnated granular ammonium sulfate remained dry and free-flowing. In contrast, granulated urea formed clusters, glistened or appeared wet and exhibited a viscous flow when impregnated with 23.6 liters of Edge EC/tonne of fertilizer. This condition did not begin to appear in granular ammonium sulphate until impregnated with 50 liter6 of Edge EC/tonne of fertilizer.
As used herein, dry or substantially dry refer6 to the appearance of fertilizer, such a6 granular ammonium 6ulfate, which is different from fertilizers which appear wet or 133322~
glisten upon impregnation with an amount of herbicide. The term dry, therefore, is not used in the strict sense of being bone dry, nor is the term meant to be limited to a prescribed moisture or liquid content. A simple determination of whether a fertilizer i6 wet or dry can be made by placing a quantity of impregnated ammonium sulfate granules in a glass-sided vessel and observing whether the particles glisten and the sides of the glass become wet.
Although the invention has been described with respect to the preferred embodiments di~cussed above, it is clearly understood that this is by way of example only, and that the invention is not limited to the particulars disclosed but extends to all eguivalents within the scope of the claims.
Claims (62)
1. A fertilizer composition comprising a free-flowing granular ammonium sulfate having a Pfizer hardness of greater than 5.0 pounds and a pH of 4.0 or less impregnated with a herbicide.
2. The fertilizer composition as defined by claim 1, wherein said herbicide is selected from the group consisting of liquid herbicides and emulsifiable herbicide concentrates.
3. The fertilizer composition as defined by claim 2, wherein said emulsifiable herbicide concentrates are members selected from the group consisting of Avadex BW?
(triallate), Edge EC? (ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, and mixtures thereof.
(triallate), Edge EC? (ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, and mixtures thereof.
4. The fertilizer composition as defined by claim 3, wherein said emulsifiable herbicide concentrates are selected from the group consisting of Avadex BW?
(triallate) and Edge EC? (ethafluralin).
(triallate) and Edge EC? (ethafluralin).
5. The fertilizer composition as defined by claim 4, wherein said herbicide is Edge EC? (ethafluralin).
6. The fertilizer composition as defined by claim 1, wherein said granular ammonium sulfate comprises more than about 0.05% by weight of a metal selected from the group consisting of aluminum and iron and has a pH of less than about 4Ø
7. The fertilizer composition as defined by claim 1, wherein said granular ammonium sulfate comprises a metal selected from the group consisting of aluminum and iron and has a pH of between about 2.5 and 4Ø
8. The fertilizer composition as defined by claim 1, wherein said granular ammonium sulfate has a Pfizer hardness of greater than about 6.8 pounds.
9. The fertilizer composition as defined by claim 1, wherein more than about 85.7% of said granular ammonium sulfate are particles having a size equal to or greater than +10 Tyler mesh screen.
10. The fertilizer composition as defined by claim 1, wherein said amount of herbicide is up to about 60 liters/tonne of fertilizer.
11. The fertilizer composition as defined by claim 10, wherein said fertilizer composition is substantially dry and free-flowing.
12. The fertilizer composition as defined by claim l0, wherein said amount of herbicide is greater than about 23.5 liters/tonne.
13. The fertilizer composition as defined by claim 11, wherein said amount of herbicide is greater than about 28.5 liters/tonne of fertilizer.
14. The fertilizer composition as defined by claim 12, wherein said amount of herbicide is greater than about 30 liters/tonne of fertilizer.
15. The fertilizer composition as defined by claim 13, wherein said amount of herbicide is greater than about 40 liters/tonne of fertilizer.
16. The fertilizer composition as defined by claim 14, wherein said amount of herbicide is greater than about 50 liters/tonne of fertilizer.
17. A free-flowing fertilizer composition comprising a free-flowing granular ammonium sulfate having a Pfizer hardness greater than 5.0 pounds and a pH of 4.0 or less impregnated with a herbicide in an amount greater than about 23.5 liters/tonne of fertilizer.
18. The free-flowing fertilizer composition as defined by claim 17, wherein said amount of herbicide is up to about 60 liters/tonne of fertilizer.
19. The free-flowing fertilizer composition as defined by claim 18, wherein said fertilizer composition is substantially dry.
20. The free-flowing fertilizer composition as defined by claim 18, wherein said amount of herbicide is greater than about 28.5 liters/tonne of fertilizer.
21. The free-flowing fertilizer composition as defined by claim 20, wherein said amount of herbicide is greater than about 30 liters/tonne of fertilizer.
22. The free-flowing fertilizer composition as defined by claim 21, wherein said amount of herbicide is greater than about 40 liters/tonne of fertilizer.
23. The free-flowing fertilizer composition as defined by claim 22, wherein said amount of herbicide is greater than about 50 liters/tonne of fertilizer.
24. The free-flowing fertilizer composition as defined by claim 17, wherein said granular ammonium sulfate comprises a metal selected from the group consisting of aluminum and iron and has a pH of between about 2.5 and 4Ø
25. The free-flowing fertilizer composition as defined by claim 17, wherein said granular ammonium sulfate comprises more than about 0.05% by weight of a metal selected from the group consisting of aluminum and iron and has a pH of less than about 4Ø
26. The free-flowing fertilizer composition as defined by claim 17, wherein said granular ammonium sulfate has a Pfizer hardness of greater than about 6.8 pounds.
27. The free-flowing fertilizer composition as defined by claim 17, wherein more than about 85.7% of said granular ammonium sulfate are particles having a size equal to or greater than +10 Tyler mesh screen.
28. The free-flowing fertilizer composition as defined by claim 17, wherein said herbicide is selected from the group consisting of liquid herbicides and emulsifiable herbicide concentrates.
29. The free-flowing fertilizer composition as defined by claim 28, wherein said emulsifiable herbicide concentrates are members selected from the group consisting of Avadex BW? (triallate), Edge EC? (ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, and mixtures thereof.
30. The free-flowing fertilizer composition as defined by claim 29, wherein said emulsifiable liquid herbicide concentrates are selected from the group consisting of Avadex BW? (triallate) and Edge EC?
(ethafluralin).
(ethafluralin).
31. The free-flowing fertilizer composition as defined by claim 30, wherein said herbicide is Edge EC?
(ethafluralin).
(ethafluralin).
32. A method for producing fertilizer comprising impregnating a free-flowing granular ammonium sulfate fertilizer having a Pfizer hardness of greater than 5.0 and a pH of 4.0 or less with a liquid agricultural treatment composition of a herbicide in an amount greater than about 23.5 liters/tonne of fertilizer, wherein said fertilizer remains sufficiently free-flowing for application by conventional fertilizer application means.
33. The method as defined by claim 32, wherein said fertilizer is impregnated with said liquid agricultural treatment composition in an amount of greater than about 28.5 liters/tonne of fertilizer.
34. The method as defined by claim 33, wherein said fertilizer is impregnated with said liquid agricultural treatment composition in an amount of greater than about 30 liters/tonne of fertilizer.
35. The method as defined by claim 34, wherein said fertilizer is impregnated with said liquid agricultural treatment composition in an amount of greater than about 40 liters/tonne of fertilizer.
36. The method as defined by claim 35, wherein said fertilizer is impregnated with said liquid agricultural treatment composition in an amount of greater than about 50 liters/tonne of fertilizer.
37. The method as defined by claim 36, wherein said fertilizer is impregnated with said liquid agricultural treatment composition in an amount of about 60 liters/tonne of fertilizer.
38. The method as defined by claim 37, wherein said liquid agricultural treatment composition is a herbicide selected from the group consisting of a liquid herbicide and an emulsifiable herbicide concentrate.
39. The method as defined by claim 38, wherein said herbicide is an emulsifiable herbicide concentrate.
40. The method as defined by claim 39, wherein said emulsifiable herbicide concentrate is selected from the group consisting of Avadex BW? (triallate), Edge EC?
(ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, and mixtures thereof.
(ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, and mixtures thereof.
41. The method as defined by claim 40, wherein said emulsifiable herbicide concentrate is selected from the group consisting of Avadex BW? (triallate) and Edge EC?
(ethafluralin).
(ethafluralin).
42. The method as defined by claim 41, wherein said emulsifiable herbicide concentrate is Edge EC?
(ethafluralin).
(ethafluralin).
43. The method as defined by claim 42, wherein said fertilizer comprises free-flowing, non-caking ammonium sulfate granules comprising more than about 0.05% by weight of a metal selected from the group consisting of aluminum and iron having a pH of less than about 4Ø
44. The method as defined by claim 42, wherein said fertilizer comprises free-flowing, ammonium sulfate granules comprising a metal selected from the group consisting of aluminum and iron having a pH of between 2.5 and 4Ø
45. The method as defined by claim 42, wherein said fertilizer comprises free-flowing, ammonium sulfate granules having Pfizer hardness of greater than about 6.8 pounds.
46. The method as defined by claim 42, wherein said fertilizer comprises free-flowing, ammonium sulfate granules, wherein more than about 85.7% of said granules are equal to or larger than +10 Tyler mesh screen particle size.
47. A method for producing fertilizer comprising impregnating free-flowing ammonium sulfate granules having a Pfizer hardness of at least 5.0 pounds and a pH of 4.0 or less with a herbicide.
48. The method as defined by claim 47, wherein said ammonium sulfate granules comprises more than about 0.05%
by weight of a metal selected from the group consisting of aluminum and iron and have a pH of less than about 4Ø
by weight of a metal selected from the group consisting of aluminum and iron and have a pH of less than about 4Ø
49. The method as defined by claim 47, wherein said ammonium sulfate granules comprises a metal selected from the group consisting of aluminum and iron and have a pH of between 2.5 and 4Ø
50. The method as defined by claim 47, wherein said ammonium sulfate granules having a Pfizer hardness of greater than about 6.8 pounds.
51. The method as defined by claim 47, wherein more than about 85.7% of said granules are equal to or larger than +10 Tyler mesh screen particle size.
52. The method as defined by claim 47, wherein said herbicide is selected from the group consisting of a liquid herbicide and an emulsifiable herbicide concentrate.
53. The method as defined by claim 47, wherein said herbicide is an emulsifiable herbicide concentrate.
54. The method as defined by claim 53, wherein said emulsifiable herbicide concentrate is selected from the group consisting of Avadex BW? (triallate), Edge EC?
(ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, and mixtures thereof.
(ethafluralin), EPTC, EPTC plus R-25788 plus R-33865, Butylate, Butylate plus R-25788, cyanazine, trifluralin, pendimethalin, metribuzin, 2,4-D, atrazine, and mixtures thereof.
55. The method as defined by claim 54, wherein said emulsifiable herbicide concentrate is selected from the group consisting of Avadex BW? (triallate) and Edge EC?
(ethafluralin).
(ethafluralin).
56. The method as defined by claim 55, wherein said herbicide is Edge EC? (ethafluralin).
57. The method as defined in claim 47, wherein said ammonium sulfate granules are impregnated with herbicide in an amount up to 60 liters/tonne of fertilizer.
58. The method as defined by claim 57 wherein said amount is greater than about 23.5 liters/tonne.
59. The method as defined by claim 58, wherein said amount is greater than about 28.5 liters/tonne.
60. The method as defined by claim 59, wherein said amount is greater than about 30 liters/tonne.
61. The method as defined by claim 60, wherein said amount is greater than about 40 liters/tonne.
62. The method as defined by claim 61, wherein said amount is greater than about 50 liters/tonne.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US12691987A | 1987-11-30 | 1987-11-30 | |
| US126,919 | 1987-11-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1333224C true CA1333224C (en) | 1994-11-29 |
Family
ID=22427375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000584340A Expired - Fee Related CA1333224C (en) | 1987-11-30 | 1988-11-28 | Fertilizer impregnated with liquid agricultural treatment compositions, and method of impregnation |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1333224C (en) |
-
1988
- 1988-11-28 CA CA000584340A patent/CA1333224C/en not_active Expired - Fee Related
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