IE53417B1 - Fertilizer compositions,processes of making them,and processes of using them - Google Patents

Abstract

A fertilizer product in granular form, is characterised by containing as active constituent a nitrogen source selected from melamine, ammeline, ammelide, cyanuric acid, mixtures thereof, their inorganic salts, their organic salts, and mixtures thereof. The granules have strength, sizes and weights suitable for mechanical dispensing and application to the soil.

Description

This invention relates to a new fertilizer product in composite granular form, to a process for making it, and to a process for using it. More particularly, the invention relates to a granular fertilizer product in which the granules have strength, sizes, and weights suitable for mechanical dispensing and application to and into the soil. These new fertilizer granules provide a novel combination of fine particles: a particulate nitrogen source such as melamine together with a binder such as urea suitable for binding the particulate nitrogen source into granular form.

Ammonia, ammonium nitrate and urea are among the most commonly used sources of nitrogen but all of these nitrogen fertilizer materials are readily soluble in water. They are therefore subject to leaching, and their use results in a rapid release of their nitrogen. Since this necessitates repeated applications for sustained growth, or one application with higher leaching losses, there have been many developments relating to slow release nitrogen fertilizer materials. Generally such materials sacrifice nitrogen content for some degree of control over nitrogen availability.

Melamine and its hydrolysis products, ammeline, ammelide, and cyanuric acid, have been considered as potential sources of nitrogen for incorporation in fertilizer compositions or for utilization as nitrogen sources per se. Melamine has a nitrogen concent of 66.6Z. If ic could be used as a fertilizer material, it would provide a good deal of nitrogen per unit weight applied.

However, at present it Is more expensive chan urea. Moreover, commercially produced melamine is available only as a fine crystalline powder. It is manufactured in tbe form of very fine crystals because small size particles are required for the present commercial end markets for melamine, such as, for example, the - 2 production of melamine-formaldehyde resins and the production of fire retardant paints.

A typical screen analysis for one commercially available melamine, conducted with United States Standard Sieve screens, is as follows: Screen Analysis Percent Retained 40 Mesh 0-0.1 40-50 Mesh 0-0.1 50-60 Mesh 0-0.3 60-80 Mesh 0.5-5.0 80-100 Mesh 1.0-5.0 100-200 Mesh 13-30 200-325 Mesh 13-30 Thru 325 ilesh 40-60 The commercially-produced small melamine crystals are desired by the resin producers because the small crystals dissolve more readily, and any larger particles, if present, would tend to require a longer processing time; therefore, the larger particles are less desirable. In the fire retardant paint market, the melamine crystals are dispersed in the paint, where the currently used fine particle sizes produce a smoother texture in the dried paint than would larger particles.

The fine particle sizes of the commercially available melamine products make melamine a product that is not very attractive for agricultural applications. Moreover, the fine particle sizes of commercial melamine as currently produced, make it impractical to use a fertilizer material. The fine particles, if applied to the surface of the ground, would be blown away by jq even mild winds. If applied by air, as from an airplane or helicopter, drifting would be a serious problem and would cause uneven application. If applied through mechanical applicators, the fine particles would tend to form bridges and thus would plug transfer and dispensing lines. These difficulties in handling the - 5 commercially available melamine solids would make any large scale agricultural application impractical.

According to the invention there is provided a granular fertilizer product that in the soil is a source cf nitrogen fertilizer values, suitable for mechanical dispensing for application to the soil, said granules comprising: a) particles of melamine, or mineral add salts of melamine, or mixtures thereof, said particles having individual particle sizes not above 400 microns (40 mesh U.S.) in largest dimension, and b) an effective binding amount by weight of the granules, of a binder that binds said particles in granular form said binder having been solidified from the molten state so as to bind said particles in the binder, said binder, after distribution of the granules in the soil, being capable of undergoing disintegration with release of said particles thus permitting the action of water and microorganisms on said particles, said granules being suitable in granule strength and weight for mechanical dispensing and for application to the soil, the average crush strength of a sample of said granules, selected to have sizes of 3 mm. to 4 mm., being at least one pound, (454 gms) per granule.

The nitrogen source may be selected from the group of materials consisting of melamine, ammeline, ammelide, cyanuric acid, mixtures thereof. The binder is present in an amount at least sufficient to bind together - 4 the fine crystals or powder particles of the nitrogen source, to fora granules having the desired strength. It is preferably a readily soluble material that, after distribution of the granules in the soil, releases the nitrogen source particles to permit the action of water and microorganisms on the particles. The binder is selected to be compatible with the soil, and any residue of the binder should be either inert, biodegradable, soil conditioning or have plant nutrient value.

The binder may be selected from the group of materials consisting of urea, ammonium sulfate, potassium sulfate, ammonium nitrate, ammonium phosphate, potassium nitrate, potassium chloride, ammonium chloride, potassium dihydrogen phosphate, lignin sulfonate, urea formaldehyde resin, melamine formaldehyde resin, starch, latex and mixtures thereof.

In another aspect this invention resides in a process for furnishing a source of fertilizer nitrogen to field soil as a nutrient source for a crop by placing a granular fertilizer product, that in the soil is a source of nitrogen fertilizer values, on comprising applying to soil granules of said product that are from 1mm to 10mm in size, said granules consisting of a mixture comprising an amount of from 10 to 67 parts by weight of said granular product of discrete particles of a material comprising melamine, the mineral acid salts of melamine, or mixtures thereof, said particles having particle sizes not above 400 microns (40 mesh U.S.) and an effective - 5 binding amount of from 33 to 90 parts by weight of a binder that binds said discrete particles in a fora that Is granular and that, after distribution of the granules In the soil, permits the action of water and microorgan5 isms on said individual melamine particles, said granules having been formed by heating a mixture of said particles and said binder in euch a way as to permit the binder to solidify from the molten state so as to bind said particles in said binder, said granules being suitable in granule *10 strength and weight for mechanical dispensing and for application to or into the soil, the average crush strength of a sample of said granules, selected to have sizes of 3 nm. to 4 mm., being at least one pound (454 gms) per granule.

According to another aspect, the invention resides in a process for increasing the output of productive units per unit weight of fertilizer nitrogen applied, from a crop that responds to fertiliser nitrogen, comprising inserting and distributing in soil in which said crop is grown, in the root zone of said crop, a granular fertilizer product that in the soil is a source of nitrogen fertilizer values, the granules being suitable for mechanical dispensing for application to and into the soil, said granules consisting of a mixture comprising particles of a material selected from the group consisting of melamine, the mineral acid salts of melamine, and mixtures thereof, said particles having individual particle sizes not above 400 (40 mesh U.S.) in largest - 5a dimension, in an amount from 1C to 67 parts by weight of said granules, and an effective amount by weight of the granules, of a binder that binds said particles in a form which is granular, the amount of said binder being from 33 parts to 90 parts by weight of said granules, said binder, after distribution of the granules in the soil, being capable of undergoing disintegration with release of said particles thus permitting the action of water and microorganisms on said particles, said granules being suitable in granule strength and weight for mechanical dispensing and for application to or into the soil, the average crush strength of a sample of said granules, selected to have sizes of 3 mm. to 4 mm., being at least one pound (434 gms) per granule, and said granules having been formed by solidifying said binder from the molten state so as to bind said particles in said binder aid said particles furnishing from about 30% to about 90% of the fertilizer nitrogen applied to the soil.

In fertilizing crops, the total rate of application is such as to insert enough total long term fertilizer nitrogen for an entire growing season. A —--y - 6 primary advantage of this process, end of the use of the composite granular fertilizer prepared in accordance with the invention, is that the rate of application of the fertilizer generally is less than one-half of that needed to achieve comparable results when ammonium sulfate is employed as the sole source of nitrogen and is applied as a solution through an irrigation sprinkler system.

According to a still further aspect, the invention resides in a method of preparing a melamine/urea granular agglomerate adapted for use as a source of nitrogen for fertilizing applications consisting of forming a mixture of from 60 to 85 parts hy weight melamine crystals and correspondingly from 40 to 15 parts of urea powder, contacting said mixture with a spray of water or an aqueous solution of urea, agglomerating the moistened mixture to form predominantly agglomerates having a nominal size of from 1 mm.to 10 mm., drying the agglomerates at less than 93°C, annealing the dried agglomerates hy heating between 135°C and 149°C and cooling the agglomerates whereby annealed melamine—Urea fertilizer agglomerates are provided having increased crush strength.

DEFINITIONS; The term poorly water soluble refers to materials that dissolve in water at 20°C, pH7, to the extent of 5 grams per 100 grams, or less; that is, materials that form solutions of 5% or less concentration. - 7 10 The term poor solubility In pH 7 water at 20°C has the same meaning.

The term readily water soluble refers to materials that dissolve in water at 20°C, pH 7, to the extent of 20 grams per 100 grams or more, that is, materials that form solutions of 209( or greater concentration.

Based on available Information, the solubilities in water at 20°C, pH 7, for several materials useful in connection with this invention, in grams per 100 grams are: Table I Solubility Data Material Melamine Ammeline Ammelide Cyanuric acid Melamine nitrate Ammonium nitrate Ammonium sulfate g/100g 0.50 0.008 less than 0.008 0.27 0.85 192 75.4 diammonium phosphate potassium acid sulfate potassium sulfate urea 131 (at 15·) 51.4 11.1 119.3 (at Z5*C) Fertilizer products in accordance with the present invention are in granular fora, with sizes in the range from about 1 na. to 10 am., preferably 3 an. to 5 nm. They are made up to have good drillability, a desirable apparent specific gravity, and to be 1 substantially free from dusting. The granules are also made to be suitable for mechanical dispensing and application to and into the soil using modern tools.

Granular fertilizer products made in accordance with preferred embodiments of the invention may be in the form of agglomer15 ates or prills. The agglomerates may be made by any conventional technique for agglomerating fertilizer products, utilizing the poorly or slightly soluble fertilizer nitrogen sources of the present invention, followed by en annealing treatment to provide sufficient crush strength. Thus, the poorly or slightly soluble nitrogen source in an agglomerate is selected from the group consisting of melamine, ammellne, ammelide, cyanuric acid, mixtures thereof, their inorganic salts, their organic salts, and mixtures thereof. These salts are preferably selected from the group consisting of the hydrochloride, hydroiodide, metaphosphate, nitrate, orthophosphate, orthophosphate dihydrate, polyphosphate, potassium dihydrogen phosphate, bisulfate, and sulfite, and, as well, the acetate, cyanurate, chloroacetate, formate, benzoate, fumarate, lactate, maleate, and phthalate, and mixtures thereof.

These materials are characterized by poor or slight solubility in jq pH 7 water at 20’C, and by slow conversion in the soil to a form in which the nitrogen is useful to plant life growing in the soil.

These nitrogen source materials, as ordinarily available commercially or as prepared, are in the form of very fine particles. In the case of melamine, for example, the commercially - 9 available product typically has crystalline particles that are smaller In size than 10 mesh, U.S. Standard Sieve size (2mm), and generally, mostly smaller than 40 mesh U.S. (400 microns). These very fine, powdery nitrogen source materials are agglomerated through the use of a binder. Generally the binder forms at least 1 part by weight of the powdery particles, preferably at least 2 parts by weight of the powdery particles, and more preferably, at least 5' parts by weight of the powdery particles. The binder may be selected from a broad spectrum of materials, but preferably is selected to be compatible with the soil so that it and any residue thereof is either insert, biodegradable, soil-conditioning, or has some plant nutrient value.

. The binder that is used should be sufficJently strong, upon hardening or curing, to impart to the granular agglomerates a crush strength of at least 454 grams, as determined by tests on ten agglomerates randomly selected, with sizes in the range from 3 mm. to 4 mm., the results being averaged. Preferably, however, the crush strength is at least 680 grams, and more preferably, 908 grams or higher. A crush strength of about 454 grams is comparable to conventional, commercial prilled urea and is adequate strength for use in most forms of commercial application, including broadcast devices, spreaders, planter shank applicators, and for dispensing from airplanes and helicopters.

Among the preferred binders are those selected - 9a from the group consisting of lignin sulfonate and its salts, starch, urea, urea-formaldehyde resins, melamineformaldehyde resins, and latices of synthetic polymeric materials. Those binders are most preferred that have plant nutrient value, as do urea, urea-formaldehyde and melamine-formaldehyde resins· In one preferred agglomeration technique, the melamine powder is combined with from 5 to 25 parts by weight of powdered urea to form a blend. This blend is then sprayed with water or with a solution of urea, in an agglomerating device such as on a rotating disc or in a rotating drum. In the case of a binder solution, the particles are coated. In the case of a water spray, the urea either goes into solution or becomes moistened and tacky, and in either state, coats the powdery melamine particles sufficiently to cause agglomeration to occur.

The agglomerates are dried at a temperature below 93°C and cooled, to form hard composites having sizes primarily in the range from about 1 mm. to about 10 mm., and preferably 3 mm. to 5 mm. These composites have good crush strength and are substantially free from dusting.

Any of the conventional agglomerating techniques can be used. Thus, all of the binder can be applied in solution. When the binder is a material such as lignin sulfonate, urea-formaldehyde resin, or melamineformaldehyde resin, application in the form of a solution is usually most convenient. The binder might also be a material such as a phenolic resin, applied from a - 10 solution, but such a material, while having excellent characteristics as a binder, has no nutrient value to contribute and is therefore less desirable. The same considerations apply to synthetic polymer latices.

The fertilizer particles of the invention may also be made in the form of prills. In the prilling operation, melamine powder la added to a molten binder material, preferably urea, to form a Blurry of the melamine powder particles in the molten urea. Droplets of this molten slurry are solidified by dropping them through a prilling tower, in the conventional fashion. While urea is the preferred material for use in preparing prills, because of its nitrogen content and ready solubility in water, and also because melamine is somewhat soluble in molten urea, other material such as sulfur could also be used, and mixtures of materials could be used. In forming urea-bound prills, it is preferred that the prill product contain at least 33 parts by weight of urea. When less urea is present, it is difficult to prepare a flowable slurry. The urea content of the prill may be as high as 90%, so that the melamine content may be in the range from 10 to 67 parts by weight of the prills. Preferably, the urea content is from 35 to 60 parts by weight of the prills, and more preferably, from 40 to 50 parts by weight.

In another example the prill comprises 40 to 65 parts by weight of the product and the binder comprises 35 to 60 parts by weight. - 10a While preferred granular products are produced by agglomeration and prilling, satisfactory products can be produced by other techniques, including extruding techniques, pressing and granulating, and bricquettlng.

For example, melamine powder,-or & powdered melamine salt0 or. the like, can be combined with a urea formaldehyde resin in powder form to form a mixture. The mixture can be pressed at an elevated temperature to cure the resin, and the resulting product can be granulated to form particles of the desired size, or the pressed, cured mass can be converted to flake form. Screening and recycling can be used as necessary to develop granules of the desired sizes.

Readily soluble binders such as urea and salts such as ammonium nitrate permit rapid disintegration of the binder of the fertilizer granules in the soil, with release of the fine melamine or other fine particles.

This may be desirable where the composite contains not only melamine but also a readily soluble, fast release nitrogen fertilizer material. Where slow release is desired, then ordinarily one of the binders is employed that loses binding power more slowly in the soil, such as, for exaniple, a urea-formaldehyde resin or a melamineformaldehyde resin.

Urea is a preferred binder for agglomerates, or for making prills, because it not only permits the production of fertilizer grandules of sufficient size, strength, and weight, for convenient application, but In - 11 addition, the urea la readily soluble and adds valuable fast release nutrient material to the soil. When used with a powdered nitrogen source characterized by poor or slightly solubility and slow conversion in the soil to a useful form, the urea dissolves rapidly and releases the fine particles of the poorly soluble nitrogen source into the soil, for slow dissolution or biodegradation.

When an agglomerate is prepared from powdered melamine and a readily water soluble binder such as urea, preferred proportions in the dried granular product obtained are from 60 to 85 parts by weight of melamine and from 40 to 15 parts by weight of urea, or more preferably, from 67 to 80 parts by weight of melamine and from 33 to 20 parts by weight of urea. The most preferred granule. comprises about 67 parts by weight melamine and about 33 parts by weight urea.

When an agglomerate is produced using an insoluble or only slightly soluble binder such as starch, or a modified starch, lignin sulfonate, urea-formaldehyde, or melamine-formaldehyde, or .one of the non-nutrient materials such as a phenolic resin, or a synthetic polymer in the form of a latex, a very slow release of nitrogen from the melamine particles (or particles of other poorly soluble nitrogen source) is obtained.

In a preferred embodiment, from 85 to 99 parts by weight of the particulate nitrogen source is combined with from 1 to 15 parts by weight of a resinous binder selected from the group consisting of lignin sulfonate, - 12 urea formaldehyde resin, melamine formaldehyde resin, latex, or mixtures thereof. In a more preferred embodiment 95 parts by weight of melamine and 5 parts by weight of the listed resinous binders are combined.

For the production of an agglomerate permitting a single application per growing season, fast release nitrogen fertilizer materials, generally an ammonium salt or urea, are advantageously used as the binder of the agglomerate. Examples of such salt-type binder materials are ammonium sulfate, potassium sulfate, ammonium phosphate, diammonium phosphate, the potassium phosphates, ammonium nitrate, potassium nitrate, potassium chloride, and ammonium chloride. When, used as a binder material in the formation of an agglomerated composite, tbe proportion of such salt-type binder material may be from 15 to 40 parts by weight of the agglomerate, and preferably is from 20 to 53 parts by weight of the agglomerate.

In addition, other .materials may be incorporated in a granular fertilizer product prepared in accordance with the invention. Such materials may be micronutrients such as zinc, magnesium, iron and boron.

One of the advantages of the use of granular fertilizer compositions prepared in accordance with the present invention is that the rate of application may be much lower in terms of nitrogen applied per acre than is true with standard fertilizer practice. Because less of the active material is actually needed, it may be desirable, to facilitate application, in some cases, to Incorporate - 12β are ammonium sulfate, potassium sulfate, ammonium phosphate, dlammonium phosphate, the potassium phosphates, ammonium nitrate, potassium nitrate, potassium chloride, and ammonium chloride. When used as a binder material in the formation of an agglomerated composite, the proportion of such salt-type binder material may be from 15% to 40% by weight of the agglomerate, and preferably is from 20% to 33% by weight of the agglomerate.

In addition, other materials may be incorporated in a granular fertilizer product prepared in accordance with the Invention. Such materials may be micronutrients such as zinc, magnesium, iron and boron.

'One of the advantages of the use of granular fertilizer compositions prepared in accordance with the present invention is that the rate of application may be much lower in terms of nitrogen applied per acre than is true with standard fertilizer practice. Because less of the active material is actually needed, it may be desirable, to facilitate application, in some cases, to incorporate-25 - 13 an inert filler. Any of the conventional filler materials may be employed· such as, for example, gypsum, clay, sand, ground sea shells, ground dolomite, and ground limestone.

Another important advantage of the use of granular fertilizer products in accordance wich the present invention is that, because of the slow release characteristics, it is possible to employ only a single application per growing season. In addition, after the Initial application, in the case of melamine based fertilizer products in particular, the release of nitrogen values into the soil appears to continue over two growing seasons. Consequently, in the second and subsequent growing seasons, even lower rates of application may be employed for given results, than may be used for the initial application.

Another aspect of the invention is the unexpected and surprising finding that furnishing a majority or all of the nitrogen fertilizer requirements by a nitrogen fertilizer source in accordance with the present invention apparently leads to a more effective production of agricultural productive units per unit weight of nitrogen applied, and per unit of growing area. An agricultural productive unit is a seed, fruit, flower, vegetable, vegetable fiber, tuber, or the like. In addition, the practice of the invention apparently leads to overall yields of plant units comparable to those obtained when following conventional, standard fertilizer practice, with its requirement for the use of much higher nitrogen fertilizer application levels.

In broad terms, this invention may be considered, ln one example, as a process for increasing the effectiveness of standard readily soluble, fast release nitrogenous fertilizers in generating productive units in agricultural crops by supplementing their action with the use of a slow release, poorly or slightly soluble 30 fertilizer nitrogen source. Thus, a combination of from about 10Z to about 50Z of the nitrogen in a standard readily water soluble, fast release nitrogenous fertilizer may be combined advantageously with from about 50Z to 90Z of poorly soluble materials recited above.

The agricultural crops expected to respond to treatment in accordance with the invention include substantially all crops, but particularly chose where fruit is the harvested unit rather than Che entire plant. Such crops include food grains, feed grains, legumes, fibers, root crops, citrus, tubers, oil bearing units including nuts, fruits and seeds, commercial vegetables, commercial melons, tree fruits, vine fruits, bush fruits and flowers. Exemplary food grains include wheat, rye, and rice. Feed grain crops Include field corn, oats, barley and sorghum. Legumes include soybeans, peanuts, beans and peas. Fiber crops include cotton, hemp and jute. Root crops include sweet potatoes and sugar beets. Citrus crops include oranges, tangerines, grapefruit, lemons and limes. Tuber crops include potatoes. Oil crops Include flax, safflower, sunflower, and castor bean. Commercial vegetable crops include lima beans, snap beans, beets, carrots, sweet corn, cucumbers, onions, green peas, and tomatoes. Commercial melon crops include cantaloupes, honeydews and watermelon. Tree fruit crops include apples, peaches, pears, cherries, and plums. Vine fruits include grapes. Bush fruits include the many different kinds of berries, especially raspberries and blueberries. Tree nut crops Include almonds, filberts, pecans and walnuts. These are intended to be exemplary only.

The invention will be better understood by reference to the following examples. Throughout this application and in these examples, all references to parts and percentages are by weight, and all references co temperatures are in degrees Celsius, unless expressly stated otherwise.

Examples of the Formation of Granules that are Useful in the Process of the Invention In all of the following examples, the melamine used was the commercially available product of Melamine Chemicals, Inc., Donaldsonville, Louisiana. It was a fine white crystalline powder - 15 having a screen analysis substantially as reported above for commercially available melamine. It was about 99.9% pure, with specifications of a maximum moisture content of 0.1%, maximum ash of 0.01%, and a density of about 1.57 g/ml.

As is pointed out in some of the following examples, crush strengths of 454 grams or greater are preferred. More preferably crush strengths of 1362 grams or more are developed, to facilitate application. Also, the bulk density of the granules should be 401bs/ft^-or 64-1 Kg/m^ or more. The preferred combination of bulk density, crush strength, and particle size makes for flexibility in and ease of application. Usually crush strengths of 1000 grams or greater are attained when the annealing step of heating to 135°C to 149°C is carried out on the melamine urea granules.

EXAMPLE I Melamine Agglomerates Using a Urea Binder Three batches of composite granules were made up, each containing different amounts of urea and melamine, with urea serving as the binder. . These batches of agglomerated granules were made in a pan agglomerator of 9 or 23cms diameter. The urea was first ground, and then blended with the melamine powder to form a homogeneous mixture. The powder mixture was fed to the pan agglomerator and sprayed with a nearly saturated solution of urea and water. The solution added about 7% urea to the dried agglomerate. The remainder of the urea - 15· content was derived from the urea powder in the ureamelamine powder mixture.

EXAMPLE II Annealed Melamine Granules A batch of granules was prepared using 67 parts of melamine crystals and 23 parts urea. The granules were made on a 18 46 cos. disc pelletizer. The urea was first ground, then blended with the melamine to form a homogeneous mixture. This mixture was fed to the pelletizer and sprayed with water. The granules were dried at 200°F. (94°C) for about 20 minutes and then were subjected to a further step of heating in a laboratory oven to 149°C for 2 -» 3 417 - 16 minutes. After cooling, the crush strength and rate of breaking apart in water were measured. These values are reported in Table I below.

Table I 5 Crush Strength (grams) Time to Disintegration in Hater Example 1 Dried Granules 600 immediate Example II 2400 20 to 30 seconds Annealed Granules This Example illustrates the relationship between time and temperature in the annealing step.

Example III Annealed Melamine Granules ήj Melamine granules prepared according to Example II were heated in separate batches at 104*C, 149'C, and 172°C for varying times. A standard laboratory oven was used. After cooling, the crush strength was measured. The results appear in Table XI. The maximum crush strength at 172°C appears at 6 minutes heating. The maximum crush strength appears at 149°C at 11 minutes heating. Shorter drying times and annealing times will be possible in production when forced air dryers or ovens will be used in place of the laboratory oven used in these examples.

Oven Temperature °C Table II Minutes Heating Crush Strength (grams) 104°C 20 560 149°C 4 350 5 881 6 978 7 1333 8 1290 9 1530 10 1480 - 17 10 11 1780 12 1300 13 1640 14 1445 15 1530 20 1454 4 763 5 1125 6 1340 7 1200 8 825 83417 Example IV Melamine Agglomerated with Urea Powder; Water Spray One beech of agglomerated granules was prepared In a pan agglomeracor as In Example I, except char all of the urea was added as a powder, and the spray applied at the pan consisted only of water. The resulting composites contained 80Z melamine and 20Z urea, and after screening to 3-4 mm., were found to have a crush strength of 953 g. using the same testing technique as in Example 1.

Example V Use of Other Binders for Agglomerating Melamine Granular agglomerates were prepared with a 16 inch pan agglomerator using melamine with several different binders. In each case, the binder, in liquid form, was sprayed on the melamine. After drying, crush strength was determined es in Example I. The results are reported in Table III, below.

TABLE III Crush Strengths Observed Melamine Agglomerated with Different Binders Crush Strength, grams of 3-4 mm.

Binder Agglomerates_ Calcium lignin sulfonate^ 908 UCAR 368 latex1 681 ή Melamine-formaldehyde resin 1544 Urea-formaldehyde resin1 454 9 Diammonium phosphate (DAP) 91 2 Ammonite nitrate 150 1Applied at 30%-50% solids. The dried agglomerates were about 5% binder.

Substantially saturated solutions used. The dried agglomerates were approximately 93% melamine, 7% salt.

Example VI Melamine Agglomerated with other Fertilizer Materials Melamine, ammonium phosphate, and potassium chloride were blended together in a 70:15:15 weight ratio. The mixture was fed to a 40 cms. pan agglomerator and spryaed with a 30% solids lignin sulfonate solution.

The dried, screened granules had a crush strength of 1000 grams in the 3-4mm. size range, and a binder content of 3%.

Example VII Melamine in Matiix of Solidified Urea Binder Melamine and urea powder were blended in a 63-37 ratio. The blend was heated until a molten slurry was obtained. The slurry was then poured onto a ennl ing slab so as to form both a thin film and a thiCA film. After cooling the thin film was broken into flakes.

The thick film, of about 4mm. thickness, was broken into granules. The crush strength of the 3-4mm. granules was exceptionally high, at 2500 grams. - 19 Example VIII A Pressed Melamine-Urea Composite A melamine-urea blend vas formed as in Example VII. This blend vas then placed in a heated platen p press at about 500 psi or 35 Kg/cm for 5 minutes, at 138°C. The resulting hot composite, in the form of a sheet about 4mm. thick, vas then removed from the press and allowed to cool. The cooled sheet was granulated, and 3·-4mm. granules of the composite had a crush strength of 2500 grams.

Example IX Melamine-Urea 60/40 Prills Melamine composite prills were prepared by heating 40 parts urea by weight with 60 parts melamine by weight. Heating vas done in an aluminium can using electric heating tape. A slurry formed at 135°C. Holes were then punched in the can bottom, allowing the slurry to drip. A plastic sheet spread on the ground caught the falling prills as they dropped from the fourth storey level.

The largest prills did not cool before landing and smashed. However, the smaller prills cooled and solidified, and were collected for strength testing. Fairly good strength results were achieved, although not measured. Crush strength would be expected to be similar to the granules of Example VII.

Example X Melamine Agglomerated with a Latex Binder. 53417 - 20 5% Union Carbide UCAR 368 Latex, 15% water, and 60% melamine were combined into a flowable slurry* A sheet of the slurry was foraed and then dried. An extremely strong composite resulted which could be granulated. The dried material contained 3% latex solids and 97% melamine. The crush strength of 3-4mm. granules was 2180 grams.

Example XI Pressed Composite of Melamine and Urea-Formaldehyde grams of urea, 70 grams melamine, and 15 ml. of 27% formaldehyde solution were mixed together and pressed at 149 C and 500 psi or 35 Kg/cm to form a thick sheet. Crush strength of 3-4mm. granules was 680 grams.

Example XII .

Melamine-Urea Agglomerates for Field Trials For field trials, 16,000 pounds (7300 Kg) of melamlne/urea composites were made using 4 foot (1.2m) diameter pan agglomerators. Different composites were produced, at the melamlne/urea ratios of 80/20, 75/25, and 67/33· Approximately 7% of the composites was provided by the urea added in the form of an aqueous binder solution, and the remaining urea was provided by powdered urea that was blended with the melamine powder prior to agglomeration.

In the foregoing examples, granular fertilizer products were prepared from commercially available, fine crystals of melamine. Similar granular fertilizer products can be prepared in substantially the sane fashion from the hydrolysis products of melamine, i.e. ammeline, ammelide, and cyanuric add, and iron salts nsde from then and from melamine. Among the salts, the reaction product of nitric add and melamine is a preferred material.

Example XIII Cora Trials Using Melamine-Urea Agglomerates; Evaluation of Different Application Techniques * Test plots totalling 40 acres (16 hectares) of sandy to light loams and silts were treated with different amounts of melamine agglomerates to provide several different levels of applied nitrogen per acre. Melamine15 urea agglomerated composites were used, prepared according to Example I and having 67 parts melamine to 33 parts urea binder; 75 parts melamine to 25 parts urea binder; and 80 parts melamine to 20 parts urea binder.

The composites were successfully applied using different techniques: 1) spreading with a Barber spreader; 2) spreading with a Barber spreader and plowing into the ground; 3) aerial application by airplane; 4) shanking into the ground during planting.

The results observed are summarised in Table IV below. 83417 - 22 Table IV Cora Trials - Effect of Application Method Nitrogen Level lbs/acre (Kp/hectare) Melamine/ Urea Application Technique Number of ears/ 100 Plants Average Number of Ears per Plant 140 -150 (156-168) 75/25 (1) 155 1.55 140-150 75/25 (2) . 147 1.47 (156-168) 140-150 75/25 (3) 155 1.55 (156-168) 150 80/20 (4) 153 1.53 (168) 0 (Control) - 132 1.32 400 UN-32 ** 129 1.29 (448) 400* * 145 1.45 (448) ♦Standard Fertilizer Practice, several applications during the growing season.

** A total of 400 lbs. or 448 Kg. N in the form of UN-32 applied in several applications during the growing season to simulate Standard Fertilizer Practice.

All of the test corn plantings reported in these examples, where compared, were made within one week of each other if not essentially simultaneously.

Corn grown in plots fertilized by method (2), broadcasting, then plowing in, looked green and robustly healthy. Corn grown in plots fertilized by broadcasting only, methods (1) and (3), had yellow as well as green S3417 - 23 foliage, but was greener than corn fertilized by method (4), shanking In post-planting, which looked yellow.

In an effort to approximate yields which would not be available until later In the year, the ear counts In the same samples were retaken with the following adjustments: full ears recorded as 1, small ears as 1/2, and nubbings as 0. This count has been recorded in Table V as effective ear counts. -24a w a fe z a ► -H *> υ a M W U s V k * * * •βαχ in o m •e m n. •e Ox • · O O CXI Ox .on Method xo CXI in •β m in co O\ CM Ch in +» a υ •H «Μ e > <5 o Φ » Φ JO to Φ $M k rM O 3 β & β +» W W tl o in CO o CXI in in o a o a □ σ H •rt c H ·= P. u ex a < Eh CXI in in CM tn o- in CXI in t'- in CM in o CM o co rM O k «Ρ c o CM tn 1 * o φ > φ c φ &0 o k +5 Φ k υ a \ & rM Φ k a •p o φ JZ o in O KO in O tn O KO in o KO CD tn o ko τ- in r· o 8 - 25 ♦Standard Fertilizer Practice, several applications during the growing season.

♦♦Full ears recorded as 1, small ears as *1/2, and nubbins as 0.

«♦♦Bar sizes were also of interest: at 150 lbs (68 Kg) N, applied as a 75/25 melamine/ urea prill; -1/2 - 6 cm. diam.

SFP (168 Kg.): 4-1/2 - 5 cm. diam.

In a further evaluation, corn plants were harvested and weighed, an ear count was taken, and ear weights were recorded, from two test areas. The first area was fertilized with 75/25 melamine/urea agglomerates by broadcasting the agglomerates, then discing them in.

The second area was fertilized according to local standard fertilizer practice at 400 lbs/acre (448 Kg/hectare) N. Standard fertilizer practice calls for tie application of a total of 350 lbs or 390 Kg. to 400 lbs/acre N or 448 Kg per hectare N per year. This is accomplished by three separate steps. First, an early application is made of 200 lbs or 224 Kg. as anhydrous ammonia. Second, 400 lbs/ acre or 448 Kg/hectare of 16-20-0 is applied (based on monoammonium phosphate). Third, UN-32, comprising urea and ammonium nitrate, is applied through the irrigation sprinkler system. The results are summarized in Table V below. All samples taken were pre-dent. 53*117 -26s I +> * £ *> 3 § ί £ W «σ in •3 tn m •3 o Q fc W •P £ rt £ Q in CD CO vO tn N ο CM tn tn • m in • ▼- CM • Ch CM CM ον ιη Pre-dent Evaluation of Corn Response P •Si Ή £ VO Q P iM VO • X·* in tn • tn £ tn N. T- s«/ tn tn CM CM tn in CM CM τ— CU C o P O Φ rH Φ to φ σ Ή ο φ Β Ο ο Β Ο α ε Ο Ό Β § Β 0) α ο +> ο ιη Β Ο Β «Η φ νο CM ιη S ·§ μ pH r-i α fc Ρ <Η Ο ιη CM tn fc ο Φ Λ § co CM tn cm in r* P Φ R· o 0 fc P 0 υ o *0 c Φ 0 0 Φ j3 o fc Φ JS 0 «Η 3 P ε \ P 0 \ Φ 0 fc ε P 0 ▼4 C Φ 0 tt 0 rM *H ε O bd o «r4 6 o r4 *o P fc 0 r4 H CO O s 0 o Φ Φ HO in r- ci Eu ε <“ 43 x> φ o n H TJ Φ Φ P φ ε o go tt tn χί tn Φ fc P υ φ x in tn CM p tt tn vo cm *o G P o Ό O fc •σ φ o S3417 -27ΙΑ ιη ΑΙ •4 >-* «ί -» νο ιη ιη • · Φ Ν tn S \ο φ «4 *-* so φ τ- «β *σ c ο Ο •8 Η c φ X β μ ΙΑ > *“* 2 <§ in Ε τ- Ο Ό ο § v-χ φ >1 s a § g <§ : g rM b (0 Φ χ-> M Λ Φ h φ <0 > o 2 Λ C Ο Μ «Ρ Ο φ γΜ Φ η η μ ο Ρ, « C φ a ο η φ Φ ο φ ι* φ Ν +> μ ο k μ ο φ ο a Η μ Μ V. μ μ σ> φ 55 ο μ ο ιη ε φ (4 ιη ο γ4 03 < φ U. tn φ Φ & ζ » Ρ Φ γΗ C •d φ ο < Ο 2 ο h ea υ μ a χ ιη ιη β •ο μ ζ CJ Γ“ S 5 ο § Ο Φ • 03 <η μ rd μ β μ ο «Μ φ CU μ 0)

Claims (28)

1. A granular fertilizer product that in the eoil is a source of nitrogen fertilizer values, suitable for mechanical dispensing for application to the soil, said 5 granules comprising: a) particles of melamine, or mineral acid salts of melamine, or mixtures thereof, said particles having individual particle sizes not above 400 microns (40 mesh U.S.) in largest dimension, and 10 b) an effective binding amount by weight of the granules, of a binder that binds said particles in granular form said binder having been solidified from the molten state so as to bind said particles in the binder, said binder, after distribution of the granules in the 15 soil, being capable of undergoing disintegration with release of said particles thus permitting the action of water and microorganisms on said particles, said granules being suitable in granule strength and weight for mechanical dispensing and for application to the soil, the 20 average crush strength of a sample of said granules, selected to have sizes of 3 nan. to 4 mm., being at least one pound, (454 gms) per granule.

2. A granular fertilizer product as claimed in claim 1 in which the binder is urea and said granules have 25 been formed by heating said mixture above the melting point of urea, then cooling to solidify the urea so as to bind said particles in said urea.

3. A granular fertilizer product as claimed In claim 2 wherein the particulate material comprises from 40 to 65 parts hy weight of the product, and the binder comprises from 35 to 60 parts by weight of said granules.

4. A granular fertilizer product as claimed in claim 2 in which the relative proportions of said particulate material and said binder are from 10 to 67 parts by weight of said particulate material and from 33 to 90 parts by weight of said binder.

5. A granular fertilizer product as claimed in claim 1, wherein said particles are melamine particles and the melamine comprises from 40 to 65 parts by weight of said granules, and said binder is urea and comprises from 35 to 60 parts by weight of said granules.

6. A granular fertilizer product as claimed in claim 1 in which the binder is a readily water soluble binder that binds said particles in granular form, said binder being selected from the group including ammonium sulphate, potassium sulphate, ammonium nitrate, ammonium phosphate, potassium nitrate, potassium chloride, ammonium chloride, potassium dihydrogen phosphate, and mixtures thereof, and urea, said granules having been formed by agglomerating said mixture to cause the binder to bind said particles into granular form.

7. A granular fertilizer product as claimed in claim 6 wherein the binder is urea and said mixture consists of particles of melamine in an amount from 60 to 85 parts by weight of said granules, and wherein said urea is present in an------------ -53417 amount from 15 to 40 parts by weight of said granules.

8. A granular fertilizer product as claimed in claim 7 wherein said mixture consists of particles of melamine in an amount from 67 to 80 parts by weight of 5 said granules, and wherein said urea is present in an amount from 20 to 33 parts by weight of said granules.

9. A granular fertilizer product as claimed in claim 6 wherein said binder comprises ammonium nitrate, and wherein said binder is present in an amount from 15 10. To 40 parts by weight of said granules.

10. A granular fertilizer product as claimed in claim 6 wherein said binder comprises a mixture of ammonium phosphate and potassium chloride, and wherein said binder is present in an amount approximately 15 parts 15 each by weight of said granules.

11. A granular fertilizer product as claimed in claim 1 in which the binder is an insoluble resin binder that binds said particles in a granular form, the amount of said binder being at least 1 part by weight of said 20 granules.

12. A granular fertilizer product as claimed in claim 11 wherein the amount of said binder is at least 2 parts by weight of the granules, and said granules have been formed by agglomerating said mixture and causing 25 said binder to bind said particles in granular form.

13. · A granular fertilizer product as claimed in claim 12 wherein at least a part of the binder is applied as an aqueous spray to said particles and is a solution of a lignin sulfonate salt. - 31

14. A granular fertilizer product as claimed In claim 12 wherein the amount of aald binder is at least 5 parts by weight of aald granules and is selected from the group consisting of a urea-formaldehyde resin, a melamine-formaldehyde resin, and a lignin sulfonate salt.

15. A granular fertilizer product as claimed in claim 12 wherein said binder comprises at least 5 parts by weight of said granules and is applied as a latex.

16. A process for furnishing a source of fertilizer nitrogen to field soil as a nutrient source for a crop by placing a granular fertilizer product, that in the soil is a source of nitrogen fertilizer values, comprising applying to soil granules of said product that are from 1 mm. to 10 mm. in size, said granules consisting of a mixture comprising an amount of from 10 to 67 parts by weight of said granular product of discrete particles of a material comprising melamine, the mineral acid salts of im>Iamine, or mixtures thereof, said particles having particle sizes not above 400 microns (40 mesh U.S.) and an effective binding amount of from 33 to 90 parts by weight of a binder that binds said discrete particles in a form that is granular and that, after distribution of the granules in the soil, permits the action of water and microorganisms on said individual melamine particles, said granules having been formed by heating a mixture of said particles and said binder in such a way as to permit the hinder to solidify from the molten state so as to bind said particles in said binder, said granules being suitable 5&H7 - 32 in granule strength and weight for mechanical dispensing end for application to or into the soil, the average crush strength of a sample of said granules, selected to have sizes of 3 mm. to 4 mm., being at least one pound 5 (454 gms) per granule.

17. · A process as claimed in claim 16 wherein said binder is urea and is soluble to the extent of 20 grams or more per 100 grams of pH 7 water at 20°C, the process comprising applying the granules to the surface of the 10 soil, as through an irrigation sprinkler system, and then disrupting the soil as by discing, rototilling, or plowing, to distribute the applied material at the desired depths within the soil.

18. A process as claimed in claim 16 wherein said 15 binder is urea and is soluble in water to the extent of 20 grams or more per 100 grams of pH 7 water at 20°C, and wherein said binder, after distribution of the granules in the soil, can dissolve in soil-moisture to release said particles as discrete particles for the action of 20 water and microorganisms thereon.

19. A process as claimed in claim 16 comprising applying said granules to the soil by inserting and distributing them in said soil, said granules being formed from at least 67 parts by weight of said discrete 25 particles of melamine and not more than 33 parts by weight of binder which is urea.

20. A process for increasing the output of productive units per unit weight of fertilizer nitrogen = 33 ° applied, from a crop that responds to fertilizer nitrogen, comprising inserting and distributing in Boll in which said crop is grown, in the root zone of said crop, a granular fertilizer product that in the soil is a source 5 of nitrogen fertilizer values, the granules being suitable for mechanical dispensing for application to and into the soil, said granules consisting of a mixture comprising particles of a material selected from the group consisting of melamine, the mineral acid salts of melamine, and 10 mixtures thereof, said particles having individual particle sizes not above 400 (40 mesh U.S.) in largest dimension, in an amount from 10 to 67 parts by weight of said granules, and an effective amount by weight of the granules, of a binder that binds said particles in a form 15 which is granulrr, the amount of said binder being from 33 parts to 90 parts by weight of said granules, said binder, after distribution of the granules in the soil, being capable of undergoing disintegration with release of said particles thus permitting the action of water and 20 microorganisms on said particles, said granules being suitable in granule strength and weight for mechanical dispensing and for application to or into the soil, the average crush strength of a sample of said granules, selected to have sizes of 3 mm. to 4 mm., being at least 25 one pound (454 gms) per granule, and said, granules having been formed by solidifying said binder from the molten state so as to bind said particles in said binder and said particles furnishing from about 50% to about 90% of the - 54 fertilizer nitrogen applied to the soil.

21. A process as claimed in claim 20 wherein said particles are melamine particles, the hinder material is urea, and wherein said binder has been solidified from the 5 molten state.

22. A process as claimed in cl»im 20 wherein said crop is a good grain, a feed grain, a legume, a fiber crop, a root crop, a citrus crop, a tuber crop, a tree fruit, a tree nut, a commercial vegetable crop, a vine 10 fruit, a bush fruit, or a commercial melon crop.

23. A method for preparing a melamine/urea granular agglomerate adapted for use as a source of nitrogen for fertilizing applications consisting of forming a mixture of from 60 to 85 parts by weight melamine crystals and 15 correspondingly from 40 to 15 parts of urea powder, contacting said mixture with a spray of water or an aqueous solution of urea, agglomerating the moistened mixture to form predominantly agglomerates having a nominal size of from 1 mm to 10 mm., drying the 20 agglomerates at less than 93°C., annealing the dried agglomerates by heating between 135°C and 149°C and cooling the agglomerates whereby annealed melamine-urea fertilizer agglomerates are provided having increased crush strength.

24. 25 24. A method as claimed in claim 23 wherein the mixture is formed comprising 67 parts by weight melamine crystals and correspondingly 33 parts by weight urea powder. -3525. A method as claimed in claim 23 wherein said spraying step comprises spraying the urea melamine mixture with water.

25. 26. A granular fertiliser product substantially as hereinbefore described with reference to the Examples.

26. 27. A process substantially as hereinbefore described with reference to the Examples.

27.

28. A method of preparation substantially as hereinbefore described with reference to the Examples.