Monocalcium phosphate / monocalcium phosphate spherical nano phosphate fertilizer as well as preparation method and application thereof

Abstract

The invention discloses a monocalcium phosphate / monocalcium phosphate spherical nano phosphate fertilizer as well as a preparation method and application thereof. The phosphate fertilizer is prepared from a calcium source, a precipitator and a phosphorus source through a chemical precipitation method. The monocalcium phosphate / monocalcium phosphate spherical nano phosphate fertilizer particles are free of agglomeration, good in dispersity, uniform in size distribution and regular in morphology, and the size of the nano phosphate fertilizer particles can be controlled from 1 nm to 200 nm by adjusting the adding proportion of the precipitant. The phosphate fertilizer prepared by the preparation method disclosed by the invention has a nanoscale size, is beneficial to migration in soil and is more easily absorbed by plant root systems or leaves, and the nano phosphate fertilizer has a spherical regular morphology, is beneficial to coating of a sustained and controlled release material on the surface of the nano phosphate fertilizer, and realizes sustained and controlled release of the nano phosphate fertilizer; meanwhile, the prepared nano phosphate fertilizer contains a large number of functional groups, the surface of the nano phosphate fertilizer can be modified, and functional design of the phosphate fertilizer is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizers, and mainly relates to the size and morphology control of nano-phosphate fertilizers, and specifically relates to a calcium monohydrogen phosphate / calcium dihydrogen phosphate spherical nano-phosphate fertilizer, and a preparation method and application thereof. Background Art

[0002] Phosphorus (P) is one of the three major nutrients necessary for plant growth. Its content in the earth's crust is only 0.09%, and it is a non-renewable resource. About 74% of my country's cultivated land soil is deficient in phosphorus, and phosphorus deficiency can lead to delayed plant growth, short plants, and reduced branching and tillering. Therefore, phosphate fertilizer has become one of the most important fertilizers in agricultural production. The main varieties of phosphate fertilizers in my country are superphosphate, double superphosphate, monoammonium phosphate, diammonium phosphate and compound fertilizer. However, the existing phosphate fertilizer particles are large in size, easy to agglomerate, and have poor migration ability in the soil. Therefore, phosphorus nutrients cannot contact the root system, resulting in a decrease in the effective utilization rate of phosphorus by plants. With the development of nanotechnology, based on the excellent characteristics of nanoparticles such as small size, easy surface modification, large specific surface area, and easy migration in the soil, how to prepare nano-sized phosphate fertilizers to alleviate the situation of soil phosphorus deficiency has become a technical problem that needs to be solved in this field. Summary of the invention

[0003] In order to improve the above technical problems, the present invention provides a method for preparing calcium monohydrogen phosphate / dicalcium phosphate, comprising preparing calcium monohydrogen phosphate / dicalcium phosphate by chemical precipitation of a calcium source, a precipitant and a phosphorus source.

[0004] According to an embodiment of the present invention, the reaction molar ratio of the calcium source to the precipitant and the phosphorus source is 1:3.5×10 -4 :1~1:3.5×10 -4 :2, 1:3.5×10 for example -4 :1, 1:3.5×10 -4 :1.5、1:3.5×10 -4 :2.

[0005] According to an embodiment of the present invention, the calcium source is CaCl 2 or Ca(OH) 2 . 5

[0006] According to an embodiment of the present invention, the precipitating agent is carboxymethyl cellulose (CMC), sodium lignin sulfonate (SLS) or humic acid (HA).

[0007] According to an embodiment of the present invention, the phosphorus sources K2HPO4, Na2HPO4 and H 3 PO 4 At least one of .

[0008] According to an embodiment of the present invention, the calcium source, the precipitant and the phosphorus source are all added to the reaction system in the form of solutions. For example, a calcium source solution, a precipitant solution and a phosphorus source solution are prepared separately, and then the calcium source solution and the precipitant solution are mixed for reaction, and then the calcium monohydrogen phosphate / dicalcium phosphate is prepared by chemical precipitation in the phosphorus source solution.

[0009] In one embodiment of the present invention, the concentration of the calcium source solution is 0.1-1 mol / L, preferably 0.2-0.8 mol / L; exemplary concentrations are 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.75 mol / L, 0.8 mol / L, and 1 mol / L.

[0010] In one embodiment of the present invention, the concentration of the precipitant solution is 0.0005-0.005 mol / L, preferably 0.0007-0.004 mol / L; exemplary concentrations are 0.0005 mol / L, 0.00075 mol / L, 0.0009 mol / L, 0.001 mol / L, 0.003 mol / L, and 0.005 mol / L.

[0011] In one embodiment of the present invention, the concentration of the phosphorus source solution is 0.1-1 mol / L, preferably 0.2-0.6 mol / L; exemplary concentrations are 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.5 mol / L, 0.8 mol / L, and 1 mol / L.

[0012] In one embodiment of the present invention, the volume ratio of the calcium source solution to the precipitant solution is 1:3 to 1:1, exemplified by 1:3, 1:2, and 1:1.

[0013] In one embodiment of the present invention, the volume ratio of the calcium source solution to the phosphorus source solution is 1:3 to 1:1, exemplified by 1:3, 1:2, and 1:1.

[0014] According to an embodiment of the present invention, the mixing reaction time is 1-24 hours, exemplarily 12 hours.

[0015] According to an embodiment of the present invention, the temperature of the chemical precipitation reaction is 17°C to 25°C, for example, 17°C, 18°C, 19°C, 20°C, or 25°C.

[0016] According to an embodiment of the present invention, the reaction time of the chemical precipitation method is 10 min-60 min, exemplified by 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min.

[0017] According to an embodiment of the present invention, the preparation method also includes a process in which, after the reaction is completed, the reaction system is subjected to solid-liquid separation to obtain a reaction product. For example, the solid-liquid separation can be carried out by means known in the art, such as centrifugation. Preferably, the centrifugal speed is 6000-10000rpm, such as 7000-9000rpm, exemplified by 6000rpm, 7000rpm, 8000rpm, 9000rpm, 10000rpm. Further, the centrifugal time is 3-10min, such as 5-8min, exemplified by 3min, 4min, 5min, 6min, 7min, 8min, 9min, 10min.

[0018] According to an embodiment of the present invention, the preparation method further comprises washing the reaction product obtained by solid-liquid separation. Preferably, the washing solvent may be water. For example, the washing may be performed once, twice or more times.

[0019] According to an embodiment of the present invention, the preparation method further comprises drying the washed reaction product. For example, the drying temperature is 50-80°C, exemplified by 50°C, 60°C, 70°C, 80°C. Further, the drying time is 5h-8h, exemplified by 5h, 6h, 7h, 8h.

[0020] According to an embodiment of the present invention, the preparation method comprises the following steps:

[0021] The calcium source solution, the precipitant solution and the phosphorus source solution are reacted by chemical precipitation method; after the reaction is completed, the solid and liquid are separated, and the obtained reaction product is washed and dried to obtain calcium monohydrogen phosphate / calcium dihydrogen phosphate.

[0022] According to an embodiment of the present invention, the calcium monohydrogen phosphate / calcium dihydrogen phosphate is a nanometer-sized particle, preferably a spherical nanometer particle. Preferably, the particle size of the nanometer particle is 1 to 200 nm, for example, 2 nm to 140 nm, 40 nm to 200 nm.

[0023] According to an embodiment of the present invention, the method for preparing monocalcium phosphate comprises the following steps:

[0024] Step 1: While stirring, add mLmol / LCaCl 2 The solution is added into a precipitant solution having a concentration of 0.0007 mol / L to 0.004 mol / L at a volume ratio of 1:3 to 1:1 for reaction;

[0025] Step 2: Under stirring, add mLmol / L K2HPO4 / Na2HPO4 solution to the mixture prepared in step 1 to carry out precipitation reaction;

[0026] Step 3: The reaction product is centrifuged to collect the solid precipitate, and then dried to obtain calcium dihydrogen phosphate with a size of 2 nm to 140 nm.

[0027] In the present invention, the precipitation reaction equation of calcium monohydrogen phosphate is:

[0028] K 2 HPO 4 +CaCl 2 =CaHPO 4 ↓+2KCl

[0029] Na 2 HPO 4 +CaCl 2 =CaHPO 4 ↓+2NaCl.

[0030] According to an embodiment of the present invention, the method for preparing monocalcium phosphate comprises the following steps:

[0031] Step 1: While stirring, add mLmol / LCa(OH) 2 The suspension is added to a precipitant solution with a concentration of 0.0007 mol / L to 0.004 mol / L at a volume ratio of 1:3 to 1:1 for reaction;

[0032] Step 2: While stirring, add mLmol / LH 3 PO 4 The solution is added to the mixture prepared in step 1 to perform a precipitation reaction;

[0033] Step 3: The reaction product is centrifuged to collect the solid precipitate, and then dried to obtain calcium dihydrogen phosphate with a size of 40 nm to 200 nm.

[0034] In the present invention, the calcium dihydrogen phosphate precipitation reaction equation is:

[0035] 2H 3 PO 4 +Ca(OH) 2 =Ca(H 2 PO 4 ) 2 ↓+2H 2 O.

[0036] The present invention also provides calcium monohydrogen phosphate / calcium dihydrogen phosphate prepared by the preparation method.

[0037] According to an embodiment of the present invention, the calcium monohydrogen phosphate / calcium dihydrogen phosphate is a nanometer-sized particle, preferably a spherical nanometer particle. Preferably, the particle size of the nanometer particle is 1 to 200 nm, for example, 2 nm to 140 nm, 40 nm to 200 nm.

[0038] The present invention also provides the use of the above-mentioned monocalcium hydrogen phosphate / dicalcium phosphate as phosphate fertilizer.

[0039] The present invention also provides a phosphate fertilizer containing the above-mentioned monocalcium hydrogen phosphate / dicalcium phosphate.

[0040] According to an embodiment of the present invention, the phosphate fertilizer is a nano-phosphate fertilizer, preferably a spherical nano-phosphate fertilizer, for example, a spherical nano-phosphate fertilizer of calcium monohydrogen phosphate and / or a spherical nano-phosphate fertilizer of calcium dihydrogen phosphate.

[0041] According to an embodiment of the present invention, the particle size of the phosphate fertilizer is 1 nm to 200 nm, for example, 2 nm to 140 nm, 40 nm to 200 nm.

[0042] The present invention also provides the use of the above phosphate fertilizer in the fields of soil and / or planting, for example, as soil fertilizer and / or plant fertilizer.

[0043] The present invention also provides a soil fertilizer, which contains the above-mentioned phosphate fertilizer.

[0044] The present invention also provides a method for preparing the soil fertilizer, which comprises preparing the soil fertilizer from raw materials containing the phosphate fertilizer.

[0045] The present invention also provides a plant fertilizer, which contains the phosphate fertilizer.

[0046] The present invention also provides a method for preparing the plant fertilizer, which comprises preparing the plant fertilizer from raw materials containing the phosphate fertilizer.

[0047] Beneficial effects of the present invention:

[0048] (1) The present invention prepares uniform-sized spherical calcium monohydrogen phosphate / calcium dihydrogen phosphate nano-phosphate fertilizer for the first time by chemical precipitation method; the nano-phosphate fertilizer of the present invention has small size, uniform dispersion, regular morphology, good dispersibility in solution and no agglomeration. The preparation method of the nano-phosphate fertilizer of the present invention is simple to operate.

[0049] (2) The phosphate fertilizer prepared by the present invention is of nanometer size, which is conducive to its migration in the soil and is more easily absorbed by plant roots or leaves; and the nano-phosphate fertilizer is of spherical regular morphology, which is conducive to coating the surface with a slow-release material to achieve the slow-release of the nano-phosphate fertilizer.

[0050] (3) The nano-phosphate fertilizer prepared by the present invention contains a large number of functional groups, and its surface can be modified to achieve the functional design of the phosphate fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A and C are transmission electron microscope (TEM) images of the calcium hydrogen phosphate spherical nano-phosphate fertilizer prepared in Example 1; Figure 1 Figures B and D are the particle size analysis results of the calcium hydrogen phosphate spherical nano-phosphate fertilizer prepared in Example 1.

[0052] Figure 2 A, C, and B are transmission electron microscopy (TEM), scanning electron microscopy (SEM), and particle size analysis results of the calcium dihydrogen phosphate spherical nano-phosphate fertilizer prepared in Example 3, respectively.

[0053] Figure 3 The XRD diagrams of the calcium monohydrogen phosphate / calcium dihydrogen phosphate spherical nano-phosphate fertilizers prepared in Example 1 and Example 3, respectively. DETAILED DESCRIPTION

[0054] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0055] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0056] Example 1

[0057] The preparation method of calcium monohydrogen phosphate spherical nano-phosphate fertilizer is as follows: under stirring, 25mL of 0.2mol / L CaCl 2 The solution is slowly added to a sodium lignin sulfonate solution with a concentration of 0.00075 mol / L in a volume ratio of 1:2, and the mixture is fully reacted for 12 hours; then, under mechanical stirring, 25 mL of a 0.2 mol / L K2HPO4 solution is quickly added to the mixture prepared in step 1, and the reaction is carried out for 10 minutes at a reaction temperature of 20°C; finally, the reaction product is centrifuged, the solid precipitate is collected, and dried to prepare a calcium monohydrogen phosphate spherical nano-phosphate fertilizer.

[0058] Example 2

[0059] The preparation method of calcium monohydrogen phosphate spherical nano-phosphate fertilizer is as follows: under stirring, 25mL of 0.2mol / L CaCl 2The solution is slowly added to a 0.00075 mol / L sodium carboxymethyl cellulose solution in a volume ratio of 1:2, and the mixture is fully reacted for 12 hours; then, under mechanical stirring, 25 mL of 0.2 mol / L K2HPO4 solution is quickly added to the mixture prepared in step 1, and the reaction is carried out for 10 minutes at a reaction temperature of 20°C; finally, the reaction product is centrifuged, the solid precipitate is collected, and dried to prepare a spherical nano-calcium hydrogen phosphate fertilizer.

[0060] According to the test method for effective phosphorus content recorded in the national standard HG / T 5939-2021, 0.7882g of calcium hydrogen phosphate spherical nano-phosphate fertilizer prepared in Example 1 and Example 2 were weighed respectively, placed in a 250mL beaker, 150mL of EDTA solution with a concentration of 37.5g / L was added, and the pH value was adjusted to 12 with a sodium hydroxide solution with a concentration of 200g / L, and heated to boiling for 15min. Remove the beaker, transfer it to a 250mL volumetric flask after cooling to room temperature, add water to the volume, and mix well. Dry filter, discard the initial 2mL of filtrate, and leave the remaining filtrate in a volumetric flask for testing. Use a pipette to transfer 10mL of filtrate, place it in a 500mL beaker, add 20mL of 34% nitric acid solution (the volume ratio of nitric acid to water is 1:1), 80mL of water, heat to boiling, and continue for at least 15min. Remove, add 35mL quinoline molybdate standard solution, place in a near-boiling water bath and keep warm until precipitation and stratification. Take out the beaker and cool to room temperature. Filter with a glass crucible filter that has been dried to constant weight at 180°C in advance, first filter the upper clear liquid, then wash the precipitate 1 to 2 times by pouring method, each time with 25mL water. Move the precipitate into the filter and wash with water. Then place the precipitate together with the filter in an electric constant temperature drying oven at 180°C, and after the temperature reaches 180°C, dry for 45min. Take out, move into a dryer, cool to room temperature, and weigh. At the same time, set up a blank experiment, except that no sample solution is added, operate according to the test sample steps. Finally, after data processing, it is measured that the effective phosphorus content in the calcium hydrogen phosphate spherical nano phosphate fertilizer obtained in Examples 1 and 2 is 35%.

[0061] The data is processed as follows:

[0062] The effective phosphorus content w, measured as the mass fraction of phosphorus pentoxide, is expressed in %, and is calculated according to the formula:

[0063]

[0064] Where:

[0065] m 1 is the mass of quinoline phosphomolybdate precipitate obtained from calcium hydrogen phosphate spherical nano-phosphate fertilizer solution, in grams (g);

[0066] m 2is the mass of the quinoline phosphomolybdic acid precipitate obtained in the blank test, in grams (g);

[0067] m 3 It is the mass of calcium hydrogen phosphate spherical nano-phosphate fertilizer, in grams (g).

[0068] Figure 1 A, B, C, and D are TEM images and particle size statistical analysis results of calcium monohydrogen phosphate spherical nano-phosphate fertilizers prepared using sodium carboxymethyl cellulose and sodium lignin sulfonate as precipitants. It can be seen from the figure that the phosphate fertilizer prepared by the present invention has a spherical regular morphology of nanometer size, and has good dispersibility in aqueous solution without agglomeration.

[0069] Example 3

[0070] The preparation method of calcium dihydrogen phosphate spherical nano-phosphate fertilizer comprises the following steps: 25 mL of 0.2 mol / L Ca(OH) 2 The suspension was slowly added to a 0.00075 mol / L sodium lignin sulfonate solution at a volume ratio of 1:2, and the mixture was fully reacted for 12 h; then, 25 mL of 0.4 mol / L H 3 PO 4 The solution is quickly added to the mixture prepared in step 1, and the reaction is carried out for 10 minutes at a reaction temperature of 17° C.; finally, the reaction product is centrifuged, the solid precipitate is collected, and dried to prepare a spherical nano-calcium dihydrogen phosphate fertilizer.

[0071] Example 4

[0072] The preparation method of calcium dihydrogen phosphate spherical nano-phosphate fertilizer comprises the following steps: 25 mL of 0.2 mol / L Ca(OH) 2 The suspension was slowly added to a 0.00075 mol / L humic acid solution at a volume ratio of 1:2, and the mixture was fully reacted for 12 h. Then, 25 mL of 0.4 mol / L H 3 PO 4 The solution is quickly added to the mixture prepared in step 1, and the reaction is carried out for 10 minutes at a reaction temperature of 17° C.; finally, the reaction product is centrifuged, the solid precipitate is collected, and dried to prepare a spherical nano-calcium dihydrogen phosphate fertilizer.

[0073] According to the test method for effective phosphorus content recorded in the national standard HG / T 5939-2021, 0.8082g of spherical nano-calcium dihydrogen phosphate fertilizer prepared in Example 3 and Example 4 were weighed, placed in a 250mL beaker, 150mL of EDTA solution with a concentration of 37.5g / L was added, and the pH value was adjusted to 12 with a sodium hydroxide solution with a concentration of 200g / L, and heated to boiling for 15min. Remove the beaker, transfer it to a 250mL volumetric flask after cooling to room temperature, add water to the volume, and mix well. Dry filter, discard the first few milliliters of filtrate, and test. Use a pipette to transfer 10mL of the sample solution, place it in a 500mL beaker, add 20mL of 34% nitric acid solution (the volume ratio of nitric acid to water is 1:1), 80mL of water, heat to boiling, and continue for at least 15min. Remove it, add 35mL of quinoline molybdate standard solution, and place it in a near-boiling water bath to keep warm until precipitation and stratification. Take out the beaker and cool to room temperature. Filter with a glass crucible filter that has been dried to constant weight at 180°C in advance, first filter out the supernatant, then wash the precipitate 1 to 2 times by pouring, each time with 25mL of water. Move the precipitate into the filter and wash with water. Then place the precipitate together with the filter in an electric constant temperature drying oven at 180°C, and dry for 45 minutes after the temperature reaches 180°C. Take it out, move it into a dryer, cool to room temperature, and weigh it. At the same time, set up a blank experiment, except that no sample solution is added, follow the test sample steps. Finally, after data processing, it was measured that the effective phosphorus content in the calcium hydrogen phosphate spherical nano-phosphate fertilizer prepared in Example 3 and Example 4 was 39.42%.

[0074] The data is processed as follows:

[0075] The effective phosphorus content w, measured as the mass fraction of phosphorus pentoxide, is expressed in %, and is calculated according to the formula:

[0076]

[0077] Where:

[0078] m 1 is the mass of quinoline phosphomolybdate precipitate obtained from calcium dihydrogen phosphate spherical nano-phosphate fertilizer solution, in grams (g);

[0079] m 2 is the value of the mass of the quinoline phosphomolybdic acid precipitate obtained in the blank test, in grams (g);

[0080] m 3 It is the mass of calcium dihydrogen phosphate spherical nano-phosphate fertilizer, in grams (g).

[0081] Figure 2 A and B are TEM images and particle size statistical analysis of calcium dihydrogen phosphate spherical nano-phosphate fertilizer prepared with sodium lignin sulfonate as precipitant; Figure 2C is a SEM image of the calcium dihydrogen phosphate spherical nano-phosphate fertilizer prepared with humic acid as a precipitant. It can be seen from the figure that the calcium dihydrogen phosphate spherical nano-phosphate fertilizer prepared by the present invention has a spherical regular morphology of nanometer size, and has good dispersibility in aqueous solution and does not agglomerate.

[0082] Figure 3 The XRD diagrams of the calcium monohydrogen phosphate / calcium dihydrogen phosphate spherical nano-phosphate fertilizers prepared in Example 1 and Example 3, respectively. It can be seen from the figure that the calcium monohydrogen phosphate and calcium dihydrogen phosphate spherical nano-phosphate fertilizers prepared by the present invention conform to the crystal forms of calcium monohydrogen phosphate and calcium dihydrogen phosphate, respectively.

[0083] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing monocalcium phosphate / dicalcium phosphate, characterized in that: The method comprises preparing calcium monohydrogen phosphate / calcium dihydrogen phosphate by chemical precipitation method with a calcium source, a precipitant and a phosphorus source.

2. The preparation method according to claim 1, characterized in that The reaction molar ratio of the calcium source to the precipitant and the phosphorus source is 1:3.5×10 -4 :1~1:3.5×10 -4 :

2. Preferably, the calcium source is CaCl2 or Ca(OH)2. Preferably, the precipitating agent is carboxymethyl cellulose (CMC), sodium lignin sulfonate (SLS) or humic acid (HA). Preferably, the phosphorus source is at least one of K2HPO4, Na2HPO4 and H3PO4.

3. The preparation method according to claim 1 or 2, characterized in that: The calcium source, precipitant and phosphorus source are all added to the reaction system in the form of solutions. For example, a calcium source solution, a precipitant solution and a phosphorus source solution are prepared separately, and then the calcium source solution and the precipitant solution are mixed for reaction, and then the calcium monohydrogen phosphate / dihydrogen phosphate is prepared by chemical precipitation in the phosphorus source solution. Preferably, the concentration of the calcium source solution is 0.1 to 1 mol / L, preferably 0.2 to 0.8 mol / L. Preferably, the concentration of the precipitant solution is 0.0005-0.005 mol / L, preferably 0.0007-0.004 mol / L. Preferably, the concentration of the phosphorus source solution is 0.1 to 1 mol / L, preferably 0.2 to 0.6 mol / L. Preferably, the volume ratio of the calcium source solution to the precipitant solution is 1:3 to 1:

1. Preferably, the volume ratio of the calcium source solution to the phosphorus source solution is 1:3 to 1:

1. According to an embodiment of the present invention, the reaction temperature of the chemical precipitation method is 17° C. to 25° C.; the reaction time of the chemical precipitation method is 10 min to 60 min.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: reacting a calcium source solution, a precipitant solution and a phosphorus source solution by a chemical precipitation method; after the reaction is completed, separating the solid from the liquid, washing and drying the obtained reaction product, and obtaining calcium monohydrogen phosphate / calcium dihydrogen phosphate.

5. Calcium monohydrogen phosphate / calcium dihydrogen phosphate obtained by the preparation method described in any one of claims 1-4. Preferably, the calcium monohydrogen phosphate / calcium dihydrogen phosphate is a nanometer-sized particle, preferably a spherical nanometer-sized particle. Preferably, the particle size of the nanometer-sized particle is 1 to 200 nm, for example, 2 nm to 140 nm, 40 nm to 200 nm.

6. Use of the calcium dihydrogen phosphate / calcium dihydrogen phosphate according to claim 5 as phosphate fertilizer.

7. A phosphate fertilizer comprising the monocalcium phosphate / dicalcium phosphate according to claim 5. Preferably, the phosphate fertilizer is a nano-phosphate fertilizer, preferably a spherical nano-phosphate fertilizer, for example, a spherical nano-phosphate fertilizer of calcium monohydrogen phosphate and / or a spherical nano-phosphate fertilizer of calcium dihydrogen phosphate. Preferably, the particle size of the phosphate fertilizer is 1 nm to 200 nm, for example, 2 nm to 140 nm, 40 nm to 200 nm.

8. Use of the phosphate fertilizer according to claim 5 in the fields of soil and / or planting, for example, as soil fertilizer and / or plant fertilizer.

9. A soil fertilizer comprising the phosphate fertilizer according to claim 5.

10. A plant fertilizer comprising the phosphate fertilizer according to claim 5.

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