WO1999064372A1

WO1999064372A1 - Water soluble fertilizer compositions and processes for their preparation

Info

Publication number: WO1999064372A1
Application number: PCT/US1998/012272
Authority: WO
Inventors: Michael Gustaaf Eltink; Hendrikus Gijsbertus Adrianus Van Kaathoven; Marcel Johannes Maria Strijdonk
Original assignee: OMS Investments Inc
Current assignee: OMS Investments Inc
Priority date: 1998-06-11
Filing date: 1998-06-11
Publication date: 1999-12-16
Anticipated expiration: 2000-12-11
Also published as: AU7963698A

Abstract

Completely water soluble granular fertilizer compositions are provided which are formed from homogeneous mixtures of at least two compounds selected from the group consisting of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds, micronutrient containing compounds and mixtures thereof. Also, processes for producing the completely water soluble products are provided.

Description

WATER SOLUBLE FERTILIZER COMPOSITIONS AND PROCESSES FOR THEIR PREPARATION

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention relates to water soluble fertilizer compositions and to process for their preparation. More particularly, it relates to completely water soluble granular or particulate fertilizer compositions formed from homogeneous mixtures of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds and/or micronutrient containing compounds and mixtures thereof. It also relates to processes for producing such granular or particulate fertilizer compositions that are completely water soluble.

DESCRIPTION OF RELATED ART

NPK-fertilizer compositions contain the primary nitrogen, phosphorus and potassium macronutrients. Optionally, secondary macronutrients such as calcium, magnesium, sulfur and the like and/or micronutrients (trace elements) such as iron, manganese, zinc, copper, molybdenum, boron and the like may also be included in NPK- fertilizers. Typically, the elements are contained in the fertilizer compositions in the form of compounds. Normally, the fertilizer compositions predominantly comprise compounds containing primary and secondary macronutrients (e.g. ammonium nitrate, mono-ammonium phosphate, potassium nitrate and magnesium sulfate) and, to a minor extent, micronutrients or trace elements (e.g. boric acid, sodium molybdate and copper-EDTA) . N P K - fertilizer compositions can be categorized as either water soluble fertilizer compositions or non-water soluble fertilizer compositions. Water soluble fertilizer compositions have high rates of solubility, a high maximum solubility and leave no insolubles in a stock solution. Water soluble fertilizer compositions are normally used as a solution and, therefore, they typically are dissolved in a tank to obtain a stock solution of approximately 100 g/l and diluted to a feed solution of approximately 1 g/l by a computer controlled dosaging device. This feed solution is successively pumped through a tube netting and fed to each plant. A feed solution can also be prepared directly without a preliminary stock solution. The concentrations of both stock and feed solutions may vary within broad ranges.

Non-water soluble fertilizer compositions demonstrate very low speed of solubility and a very poor maximum solubility. They also contain considerable amounts of insolubles. The application of these non-water soluble fertilizers is not comparable with that of water soluble fertilizers. The non-water soluble fertilizers release nutrients with time due to an insoluble coating or insoluble matrix. These fertilizers are spread over the field instead of being dissolved in a tank. As the solubility is very low and the release with time is determined by factors such as temperature, type of matrix/binder or coating and the like these kinds of fertilizers cannot be used in applications suggested for water soluble fertilizers. These non-water soluble fertilizers are usually called slow release fertilizers or controlled release fertilizers.

For purposes of the present invention, water soluble fertilizer compositions are considered to be completely water soluble if 100 grams of the water soluble fertilizer composition dissolved in 1 liter of 20°C water will result in a clear solution having 0-3% by weight of insolubles. Non-water soluble fertilizer compositions do not meet this requirement since a suspension will result having an amount of insolubles far above 3% by weight when 100 grams of such non-water soluble compositions are dissolved in 1 liter of 20°C water. Water soluble, single nutrient fertilizers in granulated form such as granulated ammonium nitrate, potassium sulfate and the like have been known heretofore and non-water soluble fertilizer compositions have been available in granular form. However, completely water soluble NPK-fertilizer compositions containing combinations of primary nitrogen, phosphorus and/or potassium nutrient granules (with or without secondary macronutrients or micronutrients) have been available previously only as physical blends of ingredients in powder, or in liquid or suspension form and each of these forms of fertilizers has been found to present significant commercial and functional disadvantages. For example, powders cause dusting losses, are not free flowing and tend to cake and liquids and suspensions are high in volume (low NPK-level per unit of volume) .

German patent DE 2,040,032 describes the granulation of a complex NPK-fertilizer composition using an aqueous solution of a macromolecular vinyl compound and a surfactant as a binder for the granulation. The binders disclosed are water insoluble. Accordingly, the granular fertilizer compositions resulting from the process will release nutrients (NPK) with time but are not completely water soluble. Consequently, these fertilizer compositions may be considered to be slow release fertilizers but they cannot be categorized as completely water soluble fertilizer compositions.

SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide a granular or particulate form of completely water soluble NPK-fertilizer compositions.

A further and related significant object is to provide completely water soluble fertilizer compositions in homogeneous granular or particulate form comprising at least two compounds selected from the group consisting of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds, micronutrient containing compounds and mixtures thereof. As referred to herein the term "homogeneous" as applied to any particular granular or particulate fertilizer composition means that all of the specific compounds employed in such fertilizer composition are included, in combination, in each fertilizer granule so that the fertilizer granules are of uniform composition throughout the product as opposed to the physical blends of granules of individual compounds such as ammonium nitrate, potassium nitrate and the like which have been employed in the prior art.

Another important object is to provide processes for producing homogeneous granular forms of NPK-fertilizer compositions which are completely water soluble upon application. Thus, the present invention provides completely water soluble fertilizer compositions in homogeneous granular or particulate form comprising at least two compounds selected from the group consisting of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds, micronutrient containing compounds and mixtures thereof. For example, the fertilizer compositions of the invention may comprise homogeneous granules of a nitrogen-containing compound and a phosphorus-containing compound; or a homogeneous mixture of a nitrogen-containing compound and a phosphorus-containing compound and a potassium containing compound; or a homogeneous mixture of a nitrogen-containing compound and a secondary macronutrient containing compound and/or a micronutrient containing compound and the like.

Preferably, the fertilizer compositions of the invention comprise all three primary nutrients ( i.e. N-, P- and K-containing compounds) . All conventional N-, P- and K- compounds can be used, in all possible ratios. Examples of suitable substances are ammonium nitrate, mono- ammonium phosphate, di-ammonium phosphate, mono-potassium phosphate, tri-potassium phosphate, potassium nitrate, potassium chloride, sodium nitrate, urea, urea phosphate, and the like. Further, conveniently and preferably the fertilizer compositions include secondary macronutrients such as. ammonium sulfate, calcium nitrate, magnesium nitrate, magnesium sulfate, potassium sulfate and the like. Many commonly used compounds contain both primary and secondary nutrients, as is evident from the exemplified compounds.

Further, conveniently and preferably the fertilizer compositions additionally include at least one micronutrient or trace element containing compound. The micronutrients are preferably boron, cobalt, copper, iron, manganese, molybdenum and zinc, but other micronutrients may also be incorporated in the fertilizer compositions of the present invention.

The granules employed in producing the completely water soluble fertilizer compositions of the present invention are generated by a size enlargement process wherein small particles of each of the nutrient compounds for use in the fertilizer composition are mixed together and granulated in combination to form larger, permanent granular masses in which the original particles can still be identified. The granules have a volume average diameter which may vary from about 0.1mm up to about 10mm. Furthermore, in accordance with the present invention, combinations of the same nutrient compounds are included in each of the particular granules resulting in the production of homogeneous granules. It should be noted that such homogeneous granules are distinct from physical blends of granules of different, uncombined or mixed individual compounds. In preferred embodiments of the present invention, the homogenous granules produced in accordance with the processes of this invention will contain amounts of primary N-, P- and/or K- nutrient compounds ranging from about 20% up to 100% by weight of the fertilizer compositions. The herein specified processes for granulating water-soluble NPK-fertilizer compositions have been found to provide the following advantages over prior art techniques: - low in volume or high NPK-level per unit of volume compared to liquids and suspensions reduces dusting losses

- reduces handling hazards renders powders free flowing - densities materials

- prevents caking and lump formation creates uniform blends of solids which do not segregate improves appearance of the product - yields homogeneous granules with each granule containing the same nutrient compounds.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT IS1

The present invention contemplates both new fertilizer products and new processes for producing such products. Generally, the fertilizer compositions of the invention contain at least two primary nutrient compounds selected from the group consisting of compounds containing nitrogen, potassium and phosphorus and, preferably, the fertilizer compositions of the invention comprise all three primary nutrients ( i.e. N-, P- and K-containing compounds) . However, it should be noted that the fertilizer compositions of the present invention may be formed from any homogeneous mixture of at least two compounds selected from the group consisting of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds, micronutrient containing compounds and mixtures thereof. Suitable primary macronutrient containing compounds for use herein include ammonium nitrate, mono- ammonium phosphate, di-am onium phosphate, mono-potassium phosphate, tri-potassium phosphate, potassium nitrate, potassium chloride, sodium nitrate, urea, urea phosphate and the like. Suitable secondary macronutrients for use herein include ammonium sulfate, calcium nitrate, magnesium nitrate, magnesium sulfate, potassium sulfate and the like. The fertilizer compositions of the present invention also may contain varying amounts and ratios of trace element containing compounds such as boric acid, cobalt sulfate, copper sulfate, copper-EDTA, iron-EDTA, iron-DTPA, iron EDDHA, iron-EDDHMA, iron-HEDTA, manganese sulfate, anganese-EDTA, sodium molybdate, zinc sulfate, zinc-EDTA, and the like. Preferably, the micronutrient compounds may be incorporated into the fertilizer compositions in an amount up to about 10% by weight of the fertilizer compositions.

In addition to the nutrients, the granular fertilizer compositions of the invention may include additives. Major additives are binders, disintegrating agents and surfactants.

Binders are not necessary, but in some cases, especially in case of compositions having a high P-content, a binder assists in improving the production efficiency and product yield. Suitable binders are powdery water soluble compounds having the ability to increase the binding properties and so increase the efficiency and capacity of the compaction and granulation step. Examples of preferred binders are polyvinylpyrrolidone, maltodextrine and dextrine. Preferably, the binder may be incorporated into the fertilizer compositions in an amount of up to about 5% by weight of the fertilizer compositions.

Disintegrating agents may be added to the present fertilizer compositions to increase the solubility speed. Disintegrating agents can either develop gas providing an effervescent effect or expand to disintegrate a granule which increases the surface area per unit of volume and automatically results in an increase of the solubility speed.

An example of disintegrants based on gas generation is the combination of an acid and a hydrogencarbonate containing substance like citric acid and potassium hydrogencarbonate. Dissolving these compounds in water results in the development of the gas carbondioxide which disintegrates the granule. So the effervescence results in an increase of the solubility speed. Another example is the application of an expanding agent like a cross-linked low-substituted carboxymethyl ether of poly-α- glucopyranose.

The real solubility speed strongly depends on the concentration, whether a stirrer is available, temperature, the composition of the product and the amount of disintegrating agents.

With intensive stirring both an amount of 10 g/l and lOOg/1 at a temperature of 20°C will dissolve within 3 minutes for all compositions for both powder and granulate without disintegrants. Without stirring, lOg/1 of granulate dissolved within 30 minutes while for lOOg/1 of granulate approximately 90 minutes were needed at a temperature of 20°C. When no stirring is applied the effervescent effect of disintegrants can become rate determining. An amount of 5% citric acid and 5% potassium hydrogencarbonate in a composition results, in case no stirrer is available, in a solubility speed which equals the solubility speed with intensive stirring. Smaller amounts increase the solubility speed but do not equal the solubility speed for intensive stirring. Disintegrants may generally be incorporated into the fertilizer compositions in an amount of up to about 10% by weight of the fertilizer compositions.

To increase the efficacy of nutrient-uptake surfactants may be blended with the fertilizer compositions of the present invention. If a surfactant is added to the NPK-composition the surface tension of a droplet containing nutrients will be decreased. This will result in film forming around the leafs and roots. The increase in contact surface area and better flow properties result in a better wetting and so a better adsorption of nutrients and traces. It can be concluded that the addition of surfactants spreads the droplets and will result in faster penetration. The advantages of a faster penetration are: better rain resistance, faster effect, lower active requirement, better efficacy and no stains. Suitable surfactants are water soluble compounds (particularly, in powder form) having the ability to decrease the surface tension of water. Examples of suitable surfactants are dioctyl sulphosuccinates, methyl oleyl taurates, alkyl sarcosines, alkyl lactylates, alkyl diphenyl ether sulphonate salts, alkylnaphtalene sulphonates and the like. The faster penetration of nutrients and trace metals as a result of the decreased surface tension of water results in a higher efficacy of the fertilizer.

Surfactants may generally be incorporated into the fertilizer compositions in an amount of up to about 5% by weight of the fertilizer compositions.

Apart from the specific additives mentioned above other additives also may be incorporated in the fertilizer compositions of the present invention. To decrease the pH- value of a stock solution and to improve the solubility and brightness a small amount of citric acid can be added. Seaweed can be added to improve the microbiological activity in the soil. Other additives can be colorants or dyes in powder or liquid form. Further anti-caking and anti-dust agents could be added.

Regarding the amounts and ratios of the various components of the present fertilizer compositions, it has been found that suitable compositions may contain: a) compounds selected from the group consisting of primary macronutrients (i.e., nitrogen containing compounds, potassium containing compounds and phosphorus containing compounds) and secondary macronutrients (e.g. , magnesium containing compounds, calcium containing compounds and sulfur containing compounds and the like) in an amount of about 70-100% by weight of the fertilizer compositions;

b) compounds containing one or more trace elements in an amount of about 0-10 % by weight of the fertilizer compositions; c) a surfactant in an amount of about 0-5% by weight of the fertilizer compositions,

d) a disintegrating agent in an amount of about 0- 10% by weight of the fertilizer compositions, and

e) a binder in an amount of about 0-5% by weight of the fertilizer compositions.

The granular size of the fertilizer compositions of this invention may vary. However, it is generally preferred that the majority of the granules have sizes ranging from about 0.5 to about 5 mm.

In a further aspect of the present invention, process are provided for preparing completely water soluble fertilizer compositions in granular form. The processes comprise providing a mixture of selected compounds and granulating the mixture of compounds using a granulation apparatus and method. Possible equipment for granulation are the pellet mill, tablet press, extruder and roll compactor based on pressure compaction and the rotary drum agglomerator, prilling tower, spray column, fluidized bed and the like based on other methods.

A particularly preferred process for producing the fertilizer granules of this invention is roll compaction employing a roll compactor as the granulation apparatus therein. The advantages of roll compaction are that almost no friction occurs so that no decomposition as a result of a temperature could be observed. High temperatures are not involved in this process so that decomposition of certain substances can be avoided. Furthermore it is a positive aspect that no moisture is needed. This process is relatively easy to control and has relatively low investment costs as a result of the relatively high efficiency and capacity. Granular sizes in the range of about 0.5 to about 5 mm can be easily obtained. The product appearance is very good. In roll compaction fine powders are forced between two counter- rotating rolls. As the volume decreases through the region of maximum pressure, the material is formed into a solid compact or sheet. After the product has been compacted it must be granulated to a uniform particle size distribution.

Example l A water soluble fertilizer having NPK-composition

20-20-20 (N-P₂0₅-K₂0) was prepared by blending the following components in powder form:

Component Percentaσe by weiσht mono-ammonium phosphate 29.8 potassium nitrate 37.3 urea 24.2 magnesium sulfate (anh.) 0.29 tri-potassium phosphate 3.9 boric acid 0.14 cobalt sulfate 0.003 copper-EDTA 0.40 iron-DTPA 1.1 manganese-EDTA 0.48 sodium molybdate 0.001 zinc-EDTA 0.40 citric acid 0.50 potassium hydrogencarbonate 0.50 dioctyl sulphosuccinate 1.00

The powdery blend was granulated using a Roll

Compactor L-83 system manufactured by the Fitzpatrick Company. A pressure between 1100 an 1400 psi was applied, using a milling speed of 900-1100 rpm. The screen used was a round hole screen with a size of 5.54 mm. The screen was installed with only one deck of 863 μm. The capacity of the final product was about 100 kg/h, which is a very good result for the L-83 system. The compact efficiency was about 75%. No sticking on the rolls occurred, and the good looking sheets came out of the rolls, with a length between 5 and 15 cm. The compact was hard and crispy when broken. After breaking the flakes and milling the overall efficiency was around 55% (particles > 863 μm) . Analysis of different sieve fractions proved that the compositions of the granules of different particle sizes are identical. So if segregation occurs as a result of the choice for a wide particle size distribution to increase the capacity it does not do any harm.

A caking test proved that no caking occurred contrary to powders. The product remained free flowing. The bulk density increased about 10%.

The resulting granules have a very high maximum solubility in water, at least 300 g/l at 20°C. No insolubles are present in the solution and the solution is clear.

Due to the presence of disintegrants (citric acid in combination with potassium hydrogencarbonate) in the indicated amounts an increase of the solubility speed by a factor 2 was observed compared with the same fertilizer composition without said disintegrants (no stirring was applied) .

Although the capacity arid efficiency of the granulation step can be improved by somewhat additional binder, both were within an acceptable range. An additional amount of 1% malto dextrine resulted in an increase of the efficiency and capacity of approximately 30%. Field trials were carried out using the fertilizer of Example 1 to examine the nutrient up-take. For comparison the same fertilizer composition without dioctyl sulphosuccinate (surfactant) was also used in the field trials. The field trials showed that the addition of dioctyl sulphosuccinate resulted in a significant increase in nutrient up-take. Example 2 A water soluble fertilizer having NPK-composition 15-10-31 (N-P₂0₅-K₂0) was prepared by blending the following components in powder form:

Component Percentaαe by weiσht mono-ammonium phosphate 17.1 potassium nitrate 64 urea 10 magnesium sulfate (anh. ) 0.30 tri-potassium phosphate 4 boric acid 0.14 cobalt sulfate 0.003 copper- EDTA 0.42 iron- DTPA 1.13 manganese- EDTA 0.49 sodium molybdate 0.001 zinc EDTA 0.42 citric acid 1 potassium hydrogencarbonate 1

The resulting powder blend was granulated in the same manner as in Example 1. Substantially identical results were obtained. Due to the presence of disintegrants (citric acid in combination with potassium hydrogencarbonate) in the indicated amounts an increase of the solubility speed by a factor 3 was observed compared with the same fertilizer composition without said distintegrants. Although the capacity and efficiency of the compaction and granulation step can be improved by somewhat additional binder, both were within an acceptable range. An additional amount of 1% malto dextrine resulted in an increase of the efficiency and capacity of approximately 30%. Fxample 3 A water soluble fertilizer having NPK-composition 31-11-11 (N-P₂0₅-K₂0) was prepared by blending the following components in powder form:

Component Percentage by weight mono-potassium phosphate 21.5 potassium nitrate 8.8 urea 64.95 magnesium sulfate (anh. ) 0.33 boric acid 0.16 cobalt sulfate 0.004 copper- EDTA 0.047 iron- DTPA 1.26 manganese- EDTA 0.55 sodium molybdate 0.001 zinc- EDTA 0.47 citric acid 1 potassium hydrogencarbonate 1

The resulting powder blend was granulated in the same manner as in Example 1. Substantially identical results were obtained.

Due to the presence of disintegrants (citric acid in combination with potassium hydrogencarbonate) in the indicated amounts an increase of the solubility speed by a factor 3 was observed compared with the same fertilizer composition without said disintegrants.

Although the capacity and efficiency of the compaction and granulation step can be improved by a somewhat additional binder, both were within an acceptable range. An additional amount of 0.5% malto dextrine resulted in an increase of the efficiency and capacity of approximately 10%. Example 4 A water soluble fertilizer having NPK-composition 12-52-05 (N-P₂0₅-K₂0) was prepared by blending the following components in powder form:

Component Percentaσe by weiσht mono-ammonium phosphate 74.7 mono-potassium phosphate 9 urea 6 magnesium sulfate (anh. ) 3.35 tri-potassium phosphate 3.01 boric acid 0.16 cobalt sulfate 0.004 copper- EDTA 0.47 iron- DTPA 1.27 manganese- EDTA 0.55 sodium molybdate 0.001 zinc- EDTA 0.47 malto dextrine 1

The resulting powder blend was granulated in the same manner as in Example 1. Substantially identical results were obtained .

Due to the presence of binder (malto dextrine) in the indicated amount an increase of the efficiency and capacity of approximately 100% was observed compared with the same fertilizer composition without said binder.

If an additional amount of 1% disintegrant (a cross-linked low substituted carboxymethyl ether of poly-α- glucopyranose) was added to the composition, an increase of the solubility speed by a factor 2 was observed with the same fertilizer composition without said distintegrant. Example 5 A water soluble fertilizer having NPK-composition 13-00-45 (N-P₂0₅-K₂0) was prepared by blending the following components in powder form: Component Percentage by weight potassium nitrate 98.5 citric acid 0.5 magnesium sulfate (anh. ) 0.2 boric acid 0.06 copper- EDTA 0.03 iron- DTPA 0.45 manganese- EDTA 0.22 sodium molybdate 0.002 zinc- EDTA 0.02

Example 6

A water soluble fertilizer having NPK-composition 15-05-15 (N-P₂0₅-K₂0) was prepared by blending the following components in powder form: Component Percentage by weight ammonium nitrate 6.6 urea phosphate 11.8 potassium nitrate 33.2 magnesium nitrate [Mg(NO₃)₂.6H₂0) ] 21.1 calcium nitrate [5Ca(NO₃)₂.NH₄NO₃.10H₂O] 26.3 alkylnaphtalene sulphonate 1

Claims

CLAIMS ;

1. A completely water soluble fertilizer composition in granular form comprising a homogeneous mixture of at least two compounds selected from the group consisting of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds, micronutrient containing compounds and mixtures thereof.

2. A completely water soluble fertilizer composition according to claim 1 containing nitrogen, potassium and phosphorus compounds.

3. A completely water soluble fertilizer composition according to claim 1 or 2 wherein the secondary macronutrient containing compounds are selected from the group consisting of magnesium, calcium and sulfur containing compounds and mixtures thereof.

4. A completely water soluble fertilizer composition according to any of claims 1-3 wherein the micronutrient containing compounds are selected from the group consisting of boron, cobalt, copper, iron, manganese, molybdenum and zinc containing compounds and mixtures thereof.

5. A completely water soluble fertilizer composition according to any of claims 1-4 including a water soluble binder.

6. A completely water soluble fertilizer composition according to claim 5 wherein the water soluble binder is in powder form.

7. A completely water soluble fertilizer composition according to any of claims 1-6 including a disintegrating agent.

8. A completely water soluble fertilizer composition according to claim 7 wherein the disintegrating agent is selected from the group consisting of effervescent agents, expanding agents and mixtures thereof.

9. A completely water soluble fertilizer composition according to any of claims 1-8 including a water soluble surfactant.

10. A completely water soluble fertilizer composition according to according to claim 9 wherein the water soluble surfactant is in powder form.

11. A completely water soluble fertilizer composition according to any of claims 1-10 wherein the granular size of the water soluble fertilizer composition ranges from about 0.5 to about 5 mm.

12. A completely water soluble fertilizer composition comprising: a) a homogenous mixture of at least two compounds selected from the group consisting of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds, micronutrient containing compounds and mixtures thereof; b) a surfactant; c) a disintegrating agent; and d) a binder.

13. A completely water soluble fertilizer composition according to claim 12 wherein the secondary macronutrient containing compounds are selected from the group consisting of magnesium, calcium and sulfur containing compounds and mixtures thereof.

14. A completely water soluble fertilizer composition according to claim 12 or 13 wherein the micronutrient containing compounds are selected from the group consisting of boron, cobalt, copper, iron, manganese, molybdenum and zinc containing compounds and mixtures thereof.

15. A completely water soluble fertilizer composition according to any of claims 12-14 wherein the amount of nitrogen containing compounds, potassium containing compounds and phosphorus containing compounds in the fertilizer composition is in a range of about 20% to 100% by weight of the fertilizer composition.

16. A completely water soluble fertilizer composition according to any of claims 12-15 wherein the amount of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds and secondary macronutrient containing compounds in the fertilizer composition is in a range of about 70% to 100% by weight of the fertilizer composition.

17. A completely water soluble fertilizer composition according to any of claims 12-16 wherein the amount of micronutrient containing compounds in the fertilizer is less than about 10% by weight of the fertilizer composition.

18. A completely water soluble fertilizer composition according to any of claims 12-17 wherein the amount of the surfactant in the fertilizer is less than about 5% by weight of the fertilizer composition.

19. A completely water soluble fertilizer composition according to any of claims 12-18 wherein the amount of the disintegrating agent in the fertilizer is less than about 10% by weight of the fertilizer composition.

20. A completely water soluble fertilizer composition according to any of claims 12-19 wherein the amount of the binder in the fertilizer is less than about 5% by weight of the fertilizer composition.

21. A completely water soluble fertilizer composition according to any of claims 12-20 wherein the granular size ranges from about 0.5 to about 5 mm.

22. A process for preparing a completely water soluble fertilizer composition comprising the steps of: a) providing a mixture of at least two compounds selected from the group consisting of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds, secondary macronutrient containing compounds, micronutrient containing compounds and mixtures thereof ; and b) granulating the mixture in a manner such that a homogeneous granular fertilizer is formed.

23. A process according to claim 22 wherein the mixture is granulated employing a roll compactor.

24. A process according to claim 22 or 23 wherein the amount of nitrogen containing compounds, potassium containing compounds and phosphorus containing compounds in the mixture is in a range of about 20% to 100% by weight of the fertilizer composition.

25. A process according to any of claims 22-24 wherein the secondary macronutrient containing compounds are selected from the group consisting of magnesium, calcium and sulfur containing compounds and mixtures thereof.

26. A process according to any of claims 22-25 wherein the amount of nitrogen containing compounds, potassium containing compounds, phosphorus containing compounds and secondary macronutrient containing compounds in the mixture is in a range of about 70% to 100% by weight of the fertilizer composition.

27. A process according to any of claims 22-26 wherein the amount of micronutrient containing compounds in the mixture is less than about 10% by weight of the fertilizer composition.

28. A process according to any of claims 22-27 including the step of adding a surfactant to the fertilizer composition in an amount less than about 5% by weight of the fertilizer composition.

29. A process according to any of claims 22-28 including the step of adding a disintegrating agent to the fertilizer composition in an amount less than about 10% by weight of the fertilizer composition.

30. A process according to any of claims 22-29 including the step of adding a binder to the fertilizer composition in an amount less than about 5% by weight of the fertilizer composition.