WO2006043769A1

WO2006043769A1 - Phosphoniter and confirmatory and quantitative methods of phosphoric acid and nitrogen contained in phosphoniter

Info

Publication number: WO2006043769A1
Application number: PCT/KR2005/003462
Authority: WO
Inventors: Yeun-Wook Jeung
Original assignee: Yeun-Wook Jeung
Priority date: 2004-10-18
Filing date: 2005-10-18
Publication date: 2006-04-27

Abstract

Disclosed herein are phosphoniter, which is a novel ore, and methods for the qualitative and quantitative analysis of phosphoniter. Phosphoniter, classified as lime by conventional methods, is found to be rich in phosphorus and nitrogen as measured by the qualitative and quantitative methods . Phosphoniter can be used as a natural fertilizer merely by subjecting it to a pulverization process after being mined from ore deposits. Substituting for synthetic fertilizers, the phosphoniter can solve problems of soil acidification and soil immobilization and has the advantage of being low in production cost and waste generation.

Description

[DESCRIPTION] [invention Title]

PHOSPHONITER AND CONFIRMATORY AND QUANTITATIVE METHODS OF PHOSPHORIC ACID AND NITROGEN CONTAINED IN PHOSPHONITER

[Technical Field]

The present invention relates to phosphoniter, which is a novel mineral, and qualitative and quantitative analysis methods therefor. More particularly, the present invention relates to phosphoniter, which is useful as a fertilizer, and methods for determining the presence and contents of phosphoric acid and nitrogen in^' phosphoniter.

[Background Art]

Phosphoniter, a novel material provided by the present invention, has been classified as lime (CaCOa) on the basis that it is found to have the same diffraction values when analyzed by an X ray diffractiometer (X,R,D) and to show a weight loss of about 40 % when baked for 8 hours at 900⁰C. In fact, phosphoniter, the material of interest of the present invention, has been regarded as low grade lime in the scientific world and the mining industry because conventional physicochemical analysis methods detect 0.03% or less of phosphoric acid and 0.3% or less of nitrogen in the material.

However, based on the observation that the mineral of interest turns red when baked at 900⁰C for 8 hours, which was made during a baking physical experiment conducted by the present inventor, doubt was cast upon the belief that the mineral is lime. Intensive research into the red baked material resulted in the finding that the red component is phosphor (P) and the mineral is phosphoniter rather than lime. The quantitative analysis conducted by the present inventor revealed an abundance of phosphorous and nitrogen, both essential elements for plant and animal nutrition, in phosphoniter, indicating that phosphoniter can be used as a material for fertilizer. Acting to promote the physiological functions of crops, phosphoric acid is used as a fertilizer. Generally, phosphate mineral deposits are the only significant global resources for phosphorous, and are used to manufacture phosphate fertilizers. Phosphate rock has high-degree compounds (Caio(PO₄)₆"F₂-β) containing highly stable orthophosphate therein.

In a fertilizer plant, phosphate fertilizer is manufactured by adding sulfuric acid solvent to the ground or pulverized phosphate rock to produce calcium superphosphate consisting of water-soluble calcium diphosphate and calcium sulfate or by reacting phosphate extracts from phosphate rock with ammonia to produce the synthetic compound fertilizer diammonium phosphate.

As a kind of fused phosphate fertilizer, (CaO^•2MgO^•P₂O₅ ^•2CaSiO₃ ^•3MgO^•P₂O₅ ^•3CaSiO₃) , citrate-soluble phosphate fertilizer, can be produced by melting phosphate rock and serpentinite at 1,300-1,400⁰C in an electric furnace and quenching the molten mixture with water, followed by pulverizing the dehydrated mixture. This citrate-soluble phosphate fertilizer, however, is difficult to produce at low cost and on a large scale.

Phosphate fertilizer has contributed to increased crop productivity and yield. However, the repeated or excessive use of synthetic fertilizers makes the soil acidic and, as a result, sterile. Additionally, the waste by-products concomitant with the manufacture of synthetic fertilizers are difficult to treat without the production of pollution.

Synthetic fertilizers are also problematic in that the plant intake thereof is as low as about 20% and the remainder causes soil fixation (insolubilization) after the passage of time (about one year) so that re-absorption thereof is almost impossible, resulting in significant resource waste and economic loss.

One alternative developed to overcome the problems of synthetic fertilizers, polyphosphate (M₅PaO₅) , can retard, rather than solve, soil fixation, and entails other technical difficulties with respect to production cost and mass production.

There are various synthetic nitrogen fertilizers, including ammonium salts ( (NH₄)₂SO₄, (NH₄)₂PO₄) , nitrate (MNO3) , and organic compounds, such as urea (CO(NH₂)₂) and calcium cyanide (CaCN2) . These, all water-soluble, show a plant intake of 30 to 60% upon application to plants, and the nitrogen fertilizer that remains unabsorbed causes significant problems, such as nutrient leaching, concentration interference, excessive nutrient uptake, etc. Much research has been made to develop sparingly soluble fertilizers as solutions to the problems, but complete citrate-soluble fertilizers have not yet been successfully realized. As a source of nitrogen fertilizer, there is Chile saltpeter. This mineral is water-soluble and mined in the desert. In addition to fertilizers, Chile saltpeter finds various applications in the nitric acid industry. Another source of nitrogen fertilizer is Guano, which is the name given to the collected droppings of seabirds and bats. It is highly prized as an effective fertilizer due to its high levels (10-12%) of phosphorus and nitrogen. Guano has been harvested over a long period of time along the coast of Peru, but in a small amount.

[Disclosure] [Technical Problem]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to identify phosphoniter,- which is rich in phosphorus and nitrogen, from ores classified as lime.

Another object of the present invention is to provide methods for determining the presence and content of phosphorus and nitrogen in the phosphoniter. A further object of the present invention is to provide a natural fertilizer prepared from the phosphoniter.

[Technical Solution]

Like all elements utilized in living processes, phosphorus cycles between organic and inorganic forms; that is, any given phosphorus atom will spend part of its time as a component of living tissue and part in an inorganic substance such as phosphate rock. Phosphorus is dissolved out of phosphate rock and a part of it soaks into the soil for uptake by plants. Then, phosphorus is transferred from plants to animals and comes out as excrement or from their bones when their corpses or carcass ferment. When washing off into the rivers and thence to the sea, phosphorus is accumulated in sea organisms or incorporated into sedimentary rocks in the deep ocean basins. Upon geological upheavals, phosphorous is recycled into the land and found in ore deposits which generally have various organic matter. Sometimes, the ore deposits undergo alteration to new chemical equilibria when environments change, as in diastrophism.

Terrestrial rocks comprising phosphoniter are marine sedimentary rocks which are found in sedimentary organic phosphorus ore deposits in ocean basins. Traces of the igneous activity of magma, such as intrusive igneous rock, folding, etc., are observed around the ore deposits. In addition, the scarcity of organics indicates organics are fired to complete destruction and transformed to inorganics. Through these natural processes, phosphoniter is believed to form. In contrast to phosphate rock, phosphoniter contains . cyanamide (CN₂ ^"2), which is involved in the determination of the structure of the crystalline compound, conferring complex compound isomer properties thereto.

In accordance with one aspect of the present invention, the novel mineral phosphoniter, having an empirical formula represented by the following formula, is provided.

[Ca₅(PO₄,CN₂)3] '3OH

The composition of the phosphoniter according to the present invention is given for components and their contents in Table 1, below. TABLE 1

Phosphoniter is a polynuclear complex compound in which calcium, phosphorus, nitrogen, carbon and oxygen atoms are tied to each other through intramolecular bonds. Components of interest cannot be detected in phosphoniter by conventional analysis methods because it differs from orthophosphate in physicochemical properties.

That is, all conventional physicochemical analysis methods indicate the absence of phosphorus and nitrogen in phosphoniter.

When phosphoniter is decomposed and dried to solidification with an inorganic solvent (H₂SO₄, HCl, HNO₃,

HCIO₄) in order to convert the complex compound of phosphoniter into orthophosphoric acid, the reaction with the solvent or other added compounds results in the formation of other additional complex ions, thereby making it difficult to solidify recrystalline salts. Upon the compulsory application of heat treatment for the solidification, the sample may explode before being solidified.

When baked at 900⁰C, massive lumps of phosphoniter undergo weight loss at a rate varying from 33 to 43% according to the background atmosphere (e.g., oxidation or reduction) .

Complex compounds are hard to decompose into ions in solution in their entity, but readily undergo thermal decomposition, during which elements of each component are automatically oxidized or reduced, with some of them being volatilized.

In Table 2, baking reaction formulas of phosphoniter and its remaining and vaporized components upon baking are given- Comparison of the mass ratios of the remaining components and the vaporizing components to the molecule after baking indicates the components that cause weight loss upon baking.

TABLE 2

Baking Rxn Formulas CO₅ (PO₄, CN₂) ₃] 3OH → 5Ca0+ (P-N) ₃ -→ 3CO₂+NH3+N₂O₄

Mw Ca₅ P₃ O₂ C₃ N₆ (OH) 3 Total

Mass Ratio 30.49% 14. 18% 29.27% 5 . 49% 12. 80% 7.77 i 100%

Mass Percent of remaining components (%) ^→ <5CaO+ (P-N) ₃ >=63 .26

Mass Percent of vaporized components ( %) → <3CO₂+NH₃+N₂O₄>=36. 74

In the mixture of molecules obtained upon the pyrodecomposition of phosphoniter, discrimination between the remaining and vaporized components and between oxidized and reduced components leads to the understanding of the components which account for the red appearance upon baking.

It is never easy to quantitatively analyze the phosphate complexes of such structures for phosphorus content by converting them into orthophosphate (PO4^3~) using reagents and inorganic solvents.

It is the nitrogen of cyanamide (H2CN2) that causes isomers specific for the complex of phosphoniter. Cyanamide is hydrolyzed at room temperature¹ under a neutral or weakly acidic conduction to produce ammonia and carbonic acid, as illustrated by the following reaction formula:

H₂CN₂ + 5H₂O = H₂CO₃ + 2NH₄OH

On the other hand, while being degraded in a strongly acidic solvent, cyanamide (H₂CN₂ H₂O) acts as a strong reducing agent to reduce the structural component, phosphorous, of phosphoniter into low-oxidized phosphorus or red phosphorus. Accordingly, the reductive deprives phosphoniter of oxygen molecules, thereby interfering the ionization of the phosphoric acid of the phosphoniter into orthophosphoric acid.

The complex ionization of the cyanamide involved in the formation of the phosphoniter is inhibited by ionizing it in an aqueous solution with potassium cyanamide (K₂CN₂,H₂O) so that the phosphoric acid is converted into orthophosphate (PO4^3~) , which is readily detected. By this method, the phosphoniter is found to contain citrate- soluble phosphoric acid (P₂Os) in an amount of 15-20%.

Based on physicochemical analysis, the quantitative analysis method for phosphate is generally used for fertilizer assay by virtue of its accuracy, although samples and reagents therefor are difficult to prepare and handle.

In order to quantify phosphoniter with analytical instruments, such as an inductively coupled plasma spectrometer (ICP) , the sample must be converted to orthophosphate, which forms yellow precipitates with ammonium phosphoric molybdenic acid and ammonium. After being filtered off, the precipitates are dissolved in ammonia water, and the resulting solution is applied to the instrument.

Being capable of analyzing and identifying components of interest of phosphoniter, the analysis method according to the present invention is essential for the identification, investigation, exploitation and utilization of phosphoniter and allows the mass production of highly effective, non-pollutive, and environment-friendly natural fertilizer without chemical plants.

Phosphoniter, a new fertilizer material, has features and components beneficial for plant nutrition, but no impurities or harmful components. Accordingly, the mere application of a simple physical process, such as pulverization or grinding, to phosphoniter can produce in mass a natural citrate-soluble fertilizer which is quite different from synthetic fertilizer. Made of phosphoniter, the natural fertilizer is not water-soluble, but citrate-soluble, so that it can remain in soil for a long term without causing the problems of conventional synthetic fertilizers, such as soil acidification, soil fixation, etc., and thus can provide nutrients to plants over prolonged time periods. Once the natural fertilizer, which can sustain plant nutrition without the degradation of soil environments, has been applied to soil, cultivation can be conducted continuously for 3 to 5 years without further fertilization. Accordingly, the natural fertilizer of the present invention contributes greatly to an increase in crop yield.

The reason why the natural fertilizer made of phosphoniter is highly effective, non-polluting, environmentally-friendly, and resource-saving is that ores abundant in inorganic elements nutritive to plants are solubilized at a rate of 90% by citric acid. Without this feature, phosphoniter would not be different from phosphate rock, which is a resource for conventional synthetic fertilizer. In accordance with another aspect, the present invention is directed to a method for analyzing the content of phosphoric acid in phosphoniter, comprising the steps of filtering a solution of phosphoniter in citric acid; concentrating the filtrate in the presence of potassium chlorate, nitric acid and hydrochloric acid by heating; and quantifying the phosphoric acid content of the concentrate in a physicochemical quantitative analysis assay.

The physicochemical quantitative analysis assay for phosphoric acid useful in the present invention may be selected from among a magnesium pyrophosphate precipitation gravimetric method, a quinoline gravimetric method, a volumetric method, a phosphomolybdate yellow method, a vanadium phosphomolybdate method, a vanadium ammonium molybdate absorption method, and ICP spectrometry.

Upon the quantification of phosphoric acid, the solubilization of the phosphoniter with citric acid is suitable as a fertilizer assay, but the determination of total phosphoric acid content may employ other typical solvents. The phosphorus quantification method according to the present invention may employ various other solubilizing solvents, but the use of an excess of strong acid is compulsory.

The method for determining the content of phosphoric acid in phosphoniter in accordance with the present invention is characterized in that an excess of potassium chlorate is used and nitric acid and hydrochloric acid are added followed by concentration by heating.

For the quantification of phosphoric acid, potassium chlorate is preferably used in a weight 40 to 70 times that of the weight of the phosphoniter. When less than 40-fold weight of potassium chlorate is used, only a slight oxidation effect is obtained on phosphoniter. On the other hand, more than 70-fold weight of potassium chlorate does not bring about further addition effects.

Conventional assay methods for phosphate rock are established on the basis of physicochemical properties of orthophosphoric acid. Also, standard specimen and analytical lines (wavelength (nm) ) for instrumental analysis are based on orthophosphoric acid. Therefore, no phosphoric acid is detected from the specimen prepared from phosphoniter by conventional assay methods. According to the phosphoric acid quantification assay of the present invention, the phosphoniter is found to contain phosphoric acid in an amount of 15 to 20%.

In accordance with another aspect, the present invention is directed to a method for analyzing the content of nitrogen in the phosphoniter, comprising the steps of vaporizing a solution of phosphoniter in hydrochloric acid to solidification by heating; mixing the solid residue with sodium hydroxide; distilling the mixture with hydrogen peroxide added thereto, and adding methyl red to the distillate to quantify nitrogen with a sodium hydroxide solution.

The quantitative analysis method for the nitrogen content of the phosphoniter in accordance with the present invention is different from conventional methods in that the sample is treated with hydrochloric acid, dried to solidification, and distilled with 30% hydrogen peroxide added thereto.

The phosphoniter of the present invention is found to contain nitrogen in an amount of 12 to 15% as measured by the nitrogen quantification method of the present invention.

In accordance with another aspect, the present invention is directed to a method for identifying phosphorus in the phosphoniter, comprising the steps of: baking the phosphoniter for 4 to 8 hours at 700 to 900⁰C to observe a red appearance in the phosphoniter; adding hydrochloric acid to the red baked phosphoniter to give off an unpleasant odor; thermally treating the red baked phosphoniter at 700 to 900⁰C for an additional 16 hours to yield powder, followed by diluting the powder in water; and adding a diluted hydrochloric acid solution to the dilution to the neutralization so as to form black precipitates.

In the phosphorus identification method of the present invention, the unpleasant odor, resembling that of rotten fish, is caused by hydrogen phosphide (PH₃) which is generated as shown in the following reaction formula (1) .

Reaction Formula (1) :

5CaO, (P-N) ₃+10HCl=5Ca (Cl ) ₂ → N₂O₃ + NO₂ + 3PH₃

The black precipitates formed after the thermal treatment for 24 hours in total are black phosphorus (3P₄) , which is generated as shown in the following reaction formula (2) .

Reaction Formula (2 ) :

5CaO, (P₄)3+ 50H₂O + 10HCl=5Ca(Cl)₂ + 50H₂O → 3P₄

Complex compounds account for such physical changes of the phosphoniter. In a complex based on a coordination compound, the coordinated covalent bond between the core atom and a ligand is so weak that it readily undergoes thermal decomposition to form a molecule mixture. Reaction Formula (3) :

[Ca₅(PO₄,CN₂)₃] 3OH=5CaO + (P-N)₃-* 3CO₂+NH₃+N₂O₄

In accordance with another aspect, the present invention is concerned with a method for identifying phosphorus nitride in the phosphoniter. In this method, the qualitative analysis of phosphorus nitride is conducted by dissolving the phosphoniter in hydrochloric acid, vaporizing the solution to solidification, boiling the solid residue in water, and allowing the residue to stand to form red a precipitate.

Its formation being indicative of the completion of the qualitative analysis, the red precipitate is phosphorus nitride ((P~N₂)₃), which is formed according to the following reaction formula (4) . Reaction Formula (4) :

[Ca₅(PO₄, CN₂)₃]3OH+10HCl=5Ca(Cl)₂+(P-N₂)3 + 6H₂O Vaporization to solidification of a solution of phosphate rock in hydrochloric acid leads to the recrystallization of the phosphate rock into tricalcium phosphate, as shown in the following Reaction 5. This is because phosphate rock is ortho-phosphate.

Reaction Formula (5) :

Ca₁₀(PO₄) 6F₂+2OHCl → 10Ca(Cl)₂+6H₃Pθ4+H₂F₂ → 3Ca₃(PO₄)2+CaF2→ 2OHCl) In lieu of hydrochloric acid, aqua regia or nitric acid can also bring about the same result in the method for identifying phosphorus nitride.

In accordance with another aspect, the present invention is directed to a method for identifying the nitrogen in the phosphoniter. In this method, the qualitative analysis of nitrogen is conducted by vaporizing a solution of phosphoniter in hydrochloric acid to solidification, mixing the solid residue with sodium hydroxide, adding hydrogen peroxide to the mixture to generate gas, and contacting red litmus with the gas to change the color to blue. This is summarized by the following reaction formula 6.

Reaction Formula (6) :

5Ca (Cl) ₂, (P=N₂) ₃, 6NaOH, 6H₂O+3H₂O₂=5Ca (Cl) ₂+3Na₃PO₄→ 6NH₂

In accordance with another aspect, the present invention is directed to a method for qualitatively analyzing phosphoric acid in the phosphoniter, which comprises mixing the phosphoniter with ammonium molybdenate and ammonium nitrate and dissolving the mixture in nitric change the color to yellow.

The appearance of yellow in the sample results from the reaction of the reagents with phosphoric acid. A lack of yellow color upon reaction indicates that the sample is lime. Reaction Formula (7) :

( [Ca₅(PO₄,CN₂)₃]3OH+18(NH₄)2Mo0₄+3NH₄N0₃+34HNO₃ = 3(NH₄)2HP0₄6Moθ3→ 5Ca(NO₃)₂+24NH₄NO₃+3(NH₄)₂CN₂+18H₂O)

Merely by physical pulverization, the phosphoniter of the present invention can be changed to phosphoric fertilizer.

Used as a fertilizer, the phosphoniter of the present invention is preferably pulverized to a particle size from

40 to 300 meshes. The size of the phosphoniter powder may be varied depending on the plant to which it is to be applied. Smaller phosphoniter particle sizes allow stronger and faster fertilization effects to-be exerted on the soil.

As for phosphoniter with greater particle sizes, its effects are slower, but are sustained over a longer period of time. [Advantageous Effects]

As a resource of phosphoric acid and nitrogen, the phosphoniter of the present invention can be changed to a natural fertilizer merely by pulverization after mining. The phosphoniter is citrate-soluble, and therefore remains in soil rather than washing off in the event of rain. Plants, if necessary, secrete organic acids from their roots to solubilize the phosphoniter, thereby absorbing nutrients for their growth. The substitution of the phosphoniter of the present invention for conventional synthetic fertilizers can solve the problems occurring in the use of conventional synthetic fertilizers, such as soil acidification, soil immobilization, etc. In addition, the phosphoniter of the present invention has advantages over synthetic fertilizer in terms of production cost and waste generation.

For the exploitation of phosphoniter, it must be identified and selected from ore deposits. In this regard, the present invention provides qualitative analysis methods for identifying and selecting phosphoniter from ores which have been classified as lime. In addition, the present invention provides quantitative analysis methods for components of interest, that is, phosphoric acid and nitrogen, in phosphoniter, thereby increasing the effective use of phosphoniter. [Best Mode]

A better understanding of the present invention may^¬ be obtained through the following examples which are set forth to illustrate the quantitative analysis of the phosphoniter for phosphoric acid and nitrogen content and the qualitative analysis of the phosphoniter for the presence of phosphorus, phosphorus nitride, nitrogen and phosphoric acid, but are not to be construed as the limit of the present invention.

EXAMPLE 1: Quantitative Analysis for Phosphorus Content in Phosphoniter

To 0.2 g of phosphoniter powder in a mass flask was added 100 ml of 2% citric acid (C₆H₈O₇ H₂O) , followed by agitation for 3 hours at 30⁰C. The solution was filtered in a beaker which was then washed five times with 20 ml of distilled water. 200 ml of the resulting filtrate collected was mixed with 12g of first-grade potassium chlorate (KClO₃) 12g, 20 ml of cone, nitric acid and 10 ml of cone. hydrochloric acid, stirred with a glass rod and concentrated to 25 ml by heating. This concentrate was diluted with distilled water to form 100 ml in total. This dilution was quantitatively analyzed by a vanadium ammonium molybdate absorption method. If the sample was of strong acidity, it was neutralized with ammonia water and made weakly acidic using nitric acid. 30 min after the appearance of color with 20 ml of B colorant, the sample was assayed for phosphoric acid by measuring its absorbance (400~420 nm) . The phosphoniter was found to contain citrate-soluble phosphoric acid in an amount of 18% (4 mg of phosphoric acid expected in 10 ml of the sample) .

EXAMPLE 2: Quantitative Analysis for Phosphorus Content in Phosphoniter

To 10 ml of cone, hydrochloric acid was added 0.4 g of phosphoniter powder, and the solution was dried to solidification by heating, followed by the addition of 100 ml of saturated sodium hydroxide. This resulting mixture was placed in a distillation flask equipped with a distillation receiver containing a standard sulfuric acid solution. 100 ml of 30% hydrogen peroxide was added in increments of 5 ml to the distillation flask while distillation was conducted. When air bubbles were weak, the distillation flask was heated to distill two-thirds of the solution. After washing the end of the conduit with water, 2 or 3 drops of the indicator methyl red were added to the distillate, and nitrogen was quantitatively analyzed using a standard sodium hydroxide solution. As a result, the phosphoniter was found to contain nitrogen in an amount of 15 % by weight. (1 ml of standard sodium hydroxide solution corresponds to 0.0014 g of nitrogen.)

EXAMPLE 3: Qualitative Analysis of Phosphorus in Phosphoniter

After a ceramic pot charged with phosphoniter was sealed and thermally treated for 8 hours at 900⁰C, the phosphoniter was found to turn red. The addition of cone, hydrochloric acid to the red phosphoniter created an unpleasant odor resembling the smell of rotten fish, which was caused by hydrogen phosphide. The red baked material was further heated for an additional 16 hours at 900⁰C to pulverization into powder and diluted in water. The neutralization of the dilution with dil. hydrochloric acid (1:10) precipitated black material, which was black phosphorus.

EXAMPLE 4: Qualitative Analysis of Phosphorus Nitride in Phosphoniter

1 g of phosphoniter powder was dissolved in 20 ml of cone, hydrochloric acid, followed by filtration. The filtrate was vaporized to solidification. The solid residue was boiled in 50 ml of water and allowed to stand to precipitate a red salt, which was phosphorus nitride. EXAMPLE 5: Qualitative Analysis of Phosphorus in Phosphoniter

A solution of 1 g of phosphoniter powder in 10 ml of cone, hydrochloric acid was vaporized to solidification by heating, followed by the addition of saturated sodium hydroxide at room temperature with stirring. The resulting mixture was placed in a flask and mixed with 10 ml of 30% of hydrogen peroxide. When air bubbles were generated, red litmus paper soaked in water was placed on the inlet of the flask. Nitrogen was identified by observing the red litmus paper turn blue.

EXAMPLE 6: Qualitative Analysis of Phosphoric Acid in Phosphoniter

1 g of phosphoniter powder was mixed with 3 g of ammonium molybdate ((NH^MoC^) and 1 g of ammonium nitrate (NH₄NO₃) . After the addition of 40 ml of cone, nitric acid, the resulting mixture was allowed to stand for 30 min. The presence of phosphoric acid was identified as the mixture sample turned yellow while being dissolved.

To evaluate the effect of the phosphoniter on plant growth, crop yield, and soil, the present inventor asked specialized institutes to conduct the following experiments. EXPERIMENTAL EXAMPLE 1: Assay for Effect of Phosphoniter on Radish Growth

Experimental Plant: Radish (a Spring radish)

Experiment Institute: the National Horticultural Research Institute of the Rural Development Administration of Korea, (experimentalist: Yoon Moo-Kyoung)

Experimental Object: To evaluate citrate-soluble phosphoniter powder as a natural fertilizer by investigating the effect thereof compared to synthetic fertilizers on the growth and population of radishes. (Jan. 17, 2001 ~ July 16, 2001)

Radishes were cultivated using the phosphoniter powder of the present invention, calcium superphosphate, and fused phosphate as phosphate fertilizers. Growth states and numbers of the radishes were investigated and the results are given in Table 3, below. Urea and potassium chloride were additionally applied to each radish.

TABLE 3

EXPERIMENTAL EXAMPLE 2: Assay for Effect of Phosphoniter on Radish Growth

Experimental Plant: Radish (Autumn radish) Experiment Institute: Collage of Agricultural and Life Sciences, Seoul National University (Prof. Ph. D., Lee, Byon-Woo)

Experimental Object: To evaluate citrate-soluble phosphoniter powder as a natural fertilizer by investigating the effect thereof on the growth and population of radishes and the physicochemical change of soil (Aug. 20, 2001 - Oct. 30, 2001)

Radishes were cultivated using the phosphoniter powder of the present invention, fused phosphate fertilizer, and fused superphosphate as phosphate fertilizers. Growth states and numbers of the radishes were investigated, and the results are given in Table 4, below.

Urea and potassium chloride were additionally applied to each radish. Also, changes in the effective amount of phosphate by growth period and in pH value of the soil are given in Table 5, below.

TABLE 4

TABLE 5

EXPERIMENTAL EXAMPLE 3: Assay for Effect of Phosphoniter on Growth of Carrots

Experimental Plant: Carrot

Experiment Institute: Horticultural Department of KyoungPook National University, Korea (Prof. Ph. D., Sun, Jeon-Kyu) Experimental Object: To evaluate citrate-soluble phosphoniter powder as a natural fertilizer by investigating the effect thereof on the growth and population of carrots and the physicochemical change of soil (July 8, 2002 ~ Nov. 20, 2002) . Carrots were cultivated using the phosphoniter powder of the present invention and fused phosphate fertilizer as phosphate fertilizers. Growth states and numbers of the carrots were investigated, and the results are given in Table 6, below. Urea and potassium chloride were additionally applied to each carrot. Also, changes in the effective amount of phosphate by growth period and in pH value of soil are given in Table 7, below. TABLE 6

TABLE 7

EXPERIMENTAL EXAMPLE 4; Assay for Effect of Phosphoniter on Growth of Corn

Experimental Plant: Corn (Hybrids)

Experiment Institute: Collage of Agriculture, Life, and Environment Science, Chungbuk National University (Prof. Ph. D. Jong, Seung-Keun)

Experimental Object: To evaluate citrate-soluble phosphoniter powder as a natural fertilizer by investigating the effect thereof on the growth and population of corn (May 1, 2004 ~ Sep. 30 2004) .

Corn was cultivated using the phosphoniter powder of the present invention, fused phosphate, and fused superphosphate as phosphate fertilizers. Growth states and numbers of cobs were investigated and the results are given in Table 8, below. Urea and potassium chloride were additionally applied to each corn plant. Also, changes in the effective amount of phosphate by growth period and in pH value of soil are given in Table 9.

TABLE 8

TABLE 9

EXPERIMENTAL EXAMPLE 5: Assay for Effect of Phosphoniter on Growth of Corn

Experimental Plant: Corn (Indian Corn) Experiment Institute: Department of Biological Environment, Kangwon National University (Prof. Yang Jay) Experimental Object: investigating the effect thereof on the growth and population of corn (May 1, 2004 ~ Sep. 30 2004) .

Corn was cultivated using the phosphoniter powder of the present invention and fused phosphate as phosphate fertilizers. Growth states and numbers of corn cobs were investigated and the results are given in Table 10, below. Urea and potassium chloride were additionally applied to each corn plant. Also, changes in the effective amount of phosphate by growth period and in pH value of soil are given in Table 11.

TABLE 10

Phosphoniter B was experimented with an amount twice larger than that of phosphoniter A and showed no interference . TABLE 11

Taken together, the data obtained in the above examples, although varying slightly from one institute to another, indicate that the effect of the phosphoniter of the present invention on plant growth is similar to that of conventional synthetic fertilizers.

In addition, it is found that the phosphoniter of the present invention can be used as an environmentally friendly fertilizer because the portion remaining in the soil does not change the acidity of the soil.

The phosphoniter of the present invention was analyzed by many outside institutes and the results are given in Table 12, below.

TABLE 12

The phosphoniter of the present invention cannot be analyzed accurately using conventional analytical methods, which were conducted by the outside institutes. The phosphate content of phosphoniter, shown in Table 12, is similar to that of general rocks. The reason is because the phosphate compounds of phosphoniter cannot be quantitatively analyzed using the conventional analysis method for phosphate rocks.

In order to qualitatively and quantitatively analyze phosphoniter for phosphorus content using an instrument such as ICP, the matrix material of the sample must be removed because when phosphoniter is dissolved in a given solvent, ingredient elements thereof form new complexes with the solvent to interfere with the atomization or ionization of the element of interest (P) in the plasma.

Only after phosphoniter, a complex in a quasi-stable state, is solubilized by organic acids of weak acidity, it ishydrolyzed and degraded into phosphoric acid and ammonia by soil bacteria. Thanks to such long-term degradation, phosphoniter can overcome the problems of synthetic fertilizers, that is, soil acidification, soil immobilization, etc.

Although methods for the quantitative analysis of phosphoniter for phosphoric acid and nitrogen and for the qualitative analysis of phosphoniter for phosphorus, phosphorus nitride, nitrogen and phosphoric acid have been disclosed in the preferred embodiments for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

[industrial Applicability]

As described hereinbefore, the phosphoniter provided by the present invention is a resource of phosphoric acid and nitrogen and can be used as a natural fertilizer merely by pulverizing the ores mined from deposits.

Allowing certain components of phosphate to be detected with regard to identity and content, the quantitative and qualitative analysis methods of the present invention can be effectively used for discriminating, exploiting, developing and utilizing phosphoniter. In addition, the present invention allows the mass production of a highly effective, non-polluting, and environmentally friendly fertilizer.

Claims

[CLAIMS]

[Claim l]

Phosphoniter, represented by the following empirical formula: [Ca₅(PO₄,CN₂)₃]3OH

[Claim 2]

A method for the quantitative analysis of the content of phosphoric acid in the phosphoniter of claim 1, comprising the steps of: filtering a solution of phosphoniter in citric acid; concentrating the filtrate in the presence of potassium chlorate, nitric acid and hydrochloric acid by heating; and quantifying the phosphoric acid content of the concentrate in a physicochemical quantitative analytical assay.

[Claim 3]

A method for the quantitative analysis of the content of nitrogen in the phosphoniter of claim 1, comprising the steps of: vaporizing a solution of phosphoniter in hydrochloric acid to solidification by heating, and mixing the solid residue with sodium hydroxide; distilling the mixture with hydrogen peroxide added thereto; and adding methyl red to the distillate to quantify nitrogen with a sodium hydroxide solution.

[Claim 4]

A method for the qualitative analysis of the phosphoniter of claim 1 for the presence of phosphorus, comprising the steps of: baking the phosphoniter for 4 to 8 hours at 700 to 900⁰C to observe a red appearance in the phosphoniter; adding hydrochloric acid to the red baked phosphoniter to give off an unpleasant odor; thermally treating the red baked phosphoniter at 700 to 900⁰C for an additional 16 hours to yield powder, followed by diluting the powder in water; and adding a diluted hydrochloric acid solution to the dilution until neutralization so as to form a black precipitate.

[Claim 5]

A method for the qualitative analysis of the phosphoniter of claim 1 for the presence of phosphorus nitride, comprising the steps of: dissolving the phosphoniter in hydrochloric acid; vaporizing the solution to solidification; boiling the solid residue in water; and allowing the residue to stand to form a red precipitate.

[Claim 6]

A method for the qualitative analysis of the phosphoniter of claim 1 for the presence of nitrogen, comprising the steps of: vaporizing a solution of phosphoniter in hydrochloric acid to solidification; mixing the solid residue with sodium hydroxide, adding hydrogen peroxide to the mixture' to generate gas; and contacting red litmus with the gas to cause a color change to blue.

[Claim 7]

A method for the qualitative analysis of the phosphoniter of claim 1 for the presence of phosphoric acid, comprising the steps of: mixing the phosphoniter with ammonium molybdenate and ammonium nitrate; and dissolving the mixture in nitric acid to cause a color change to yellow.

[Claim 8]

A fertilizer, prepared from the phosphoniter of claim 1 or the phosphoniter analyzed by the method of one of claims 2 to 7.

[Claim 9]

The fertilizer according to claim 8, wherein the phosphoniter is in the form of particles having a size ranging from 40 to 500 mesh.