JP2611130B2 - Solid composition to obtain silicic acid aqueous solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an aqueous solution of silicic acid having a pH of slightly acidic to near neutral, and a method of producing a solution of SiO ₂ having a pH of slightly acidic to near neutral when a predetermined amount of water is added.
The present invention relates to a mixed composition from which a silicic acid aqueous solution containing 100 ppm or more of silicic acid is obtained.

[0002]

2. Description of the Related Art Silicic acid exhibits physiological actions such as strengthening of foliage of crops, resistance to disease and fungi, increase of insect resistance, promotion of root elongation, and partial substitution of physiological action of phosphorus. It is absorbed from the roots of crops in a neutral aqueous solution. However, the solubility of silicic acid in water from slightly acidic to neutral is only about 100 ppm at most, and generally 50 to 60 p.
pm. Due to the low dissolution of silicic acid, the amount of silicic acid absorption is low except for crops that selectively absorb silicic acid as an essential component, such as rice, often resulting in a lack of silicic acid content and the suppression of root growth. And have been observed to be more susceptible to disease and pests.

[0003] In general, silicate is not soluble in water and is used as a slow-acting fertilizer. Therefore, even if a shortage of silicic acid is found, it is impossible to replenish the shortage quickly.

On the other hand, alkali metal silicates are water-soluble silicates. However, it is strongly basic, and when used as fertilizer as it is, it harms the crop on the contrary. Further, when the basicity is neutralized, a precipitate is deposited, and the amount of dissolution of the silicic acid becomes small, so that it is difficult to use it promptly.

[0005] For this reason, if the crop is capable of solubilizing a large amount of silicic acid in a slightly acidic to neutral state that absorbs silicic acid, it can be applied as a fast-acting silicic acid fertilizer to the symptoms of silicic acid deficiency, which is a great advantage for growing the crop. It is thought to bring about.

Japanese Patent Publication No. 2-2837 proposes the use of a liquid fertilizer consisting of an aqueous solution of potassium silicate in citric acid. In this method, a silicic acid solution can be easily obtained at a high concentration, but citric acid is expensive, and the pH of the obtained liquid fertilizer is 9 or more.

The present inventors have studied various additives to stabilize a high concentration of silicic acid in an aqueous solution having a pH of 6 to 9,
A method using ethylene glycol as an additive has been proposed (JP-A-4-236555). However, this method also has the drawback that silica is precipitated during long-term storage,
It cannot be denied that the solution has problems in transportation, handling, and the like.

[0008]

SUMMARY OF THE INVENTION
A method for obtaining a silicic acid aqueous solution containing the above-mentioned silicic acid, and by adding a predetermined amount of water, to provide a solid composition capable of obtaining a pH suitable for plant absorption and obtaining an aqueous solution containing a high concentration of silicic acid. It is an object.

[0009]

At present, the main component of siliceous fertilizer is calcium metasilicate (CaSiO ₃ ), and its solubilization is similar to that of phosphoric acid in molten phosphorus fertilizer. Is believed to be When the particles come into contact with the hydrogen soil colloid, the molten phosphorus fertilizer
And Mg are contact-exchanged with H ⁺ , so that phosphoric acid is eluted, and this phosphoric acid is immediately used for plant roots. Similarly, in the case of siliceous fertilizer, it is considered that carbonic acid generated by the respiration of microorganisms or plant roots in soil causes the dissolution of calcium metasilicate by the following reaction, and this silicic acid is absorbed.

[0010]

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On the other hand, when topically applied mixed phosphorus fertilizer with a neutral salt such as ammonium sulfate or potassium sulfate, the fertilizing effect of phosphoric acid is remarkably increased, and the phosphoric acid absorption process is similar to that of superphosphate. Is also known. These facts suggest that the acid contributes to the solubilization of the active ingredients in the fused phosphorus fertilizer and the siliceous fertilizer.

The present inventors have paid attention to the similarity between the fused phosphorus fertilizer and the siliceous fertilizer, and as a result of various studies, have completed the present invention.

According to the invention, inorganic monobasic acids and polysalts
Ammonium salt of base acid and part of acid base of polybasic acid
Acid when dissolved in water substituted with monia or alkali metal
1 to 5 mol of a soluble salt exhibiting a property and an alkali metal or
Or 1 mol of alkaline earth metal silicate
And the pH of the aqueous solution is in the range of 6 to 9
Silicon containing 100 ppm or more silicic acid as SiO ₂
A composition of silicate fertilizer capable of producing an aqueous acid solution is provided.

In the production method of the present invention, the reaction between the acid salt and the alkali metal or alkaline earth metal silicate is 5 to 5.
The reaction is carried out at a molar ratio of 1: 1 and the reaction temperature is around room temperature (about 20
C. or about 20.degree. C. or more), and it is preferable to stir for about 10 to 60 minutes. When an ammonium salt of a monobasic acid or a polybasic acid is used, it is preferable to heat the reaction solution (up to an upper limit of about 60 ° C.) to proceed the reaction as described below.

The salts used in the present invention include, for example, ammonium salts of inorganic monobasic acids and polybasic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and polyphosphoric acid, and part of the acid radicals of polybasic acids with ammonia or alkali metal. A soluble salt that is acidic when dissolved in substituted water.

The silicate used in the present invention is, for example, K, N
Ortho or metasilicate of an alkali metal such as a or an alkaline earth metal such as Ca and Mg.

The molar ratio of the acidic salt to the silicate is appropriately selected depending on the kind of the acidic salt and the silicate to be used. In general, the higher the basicity of the acid in the acidic salt, the smaller the molar ratio to the silicate. For example, when NH ₄ Cl, which is an ammonium salt of a monobasic acid, is used as an acidic salt and Na ₂ SiO ₃ is used as a silicate, the molar ratio of NH ₄ Cl: Na ₂ SiO ₃ needs to be 2: 1 or more. When NH ₄ H ₂ PO ₄ which is an ammonium salt of a tribasic acid is used as a salt, NH ₃
A molar ratio of ₄ H ₂ PO ₄ : Na ₂ SiO ₃ of 1: 1 or more is sufficient. With respect to other acidic salts, the molar ratio with the silicate can be easily selected according to the above. That is, the number of moles of the acidic salt to be used must be at least an amount to neutralize the alkali metal or alkaline earth metal of the silicate used, but the effect is not improved to the left even if used in a large excess. . Generally, the acid salt can be used within a range of 5 to 1 mol per mol of the silicate. Preferably, a molar ratio of 2 to 4: 1 when using an alkaline earth metal silicate,
1.7 to 2.5: 1 when an alkali metal silicate is used
In the molar ratio range.

The amount of water to be added to the solid composition comprising the acidic salt and the silicate is not particularly limited. If a large amount is used, the concentration of the silicic acid decreases, and if the amount is too small, the silicic acid precipitates without dissolving. The amount of water added for the purpose of the present invention is as follows:
It is preferable to add a calculated amount such that the concentration becomes about 100 to 300 ppm as ₂ .

The acid salt / silicate composition added to the water is optionally heated. The heating lowers the molecular weight of the silicate to solubilize the silicic acid. When the silicate used is an alkaline earth salt, a precipitate coexists after heating. There is no problem if the solution is used as it is or only the solution is used after the precipitate is separated by filtration. NH ₄ Cl, (NH ₄ ) ₂
HPO ₄ , (NH ₄ ) ₃ PO ₄ , (NH ₄ ) ₂ SO ₄
When used, for example, heating generates excess ammonia and converts them into monoammonium salts, keeping the reaction solution slightly acidic, i.e., the present invention is based on the acidic conditions of the ammonium salts present in excess, It is presumed that the following reaction proceeds and a silicic acid solution is obtained. For example, NH ₄ C
l and CaSiO ₃

[0020]

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That is, N which is excessively present in the reaction system due to heating
As the Ca of CaSiO ₃ is replaced by H ⁺ due to the acidity of H ₄ Cl and liberated from CaSiO ₃ , H ₄ Si
O ₄ is produced, and the reaction system reacts with excess NH ₄ Cl and N
The buffering action with H ₃ maintains a pH suitable for plant absorption. As described above, in the present method, the pH of the reaction system can be appropriately selected by adjusting the kind of the acidic salt to be used and the excess amount thereof. Alkaline earth silicates that are insoluble in water also have the advantage that a silicic acid aqueous solution can be obtained by applying this method.

The composition comprising an acid salt and an alkali metal or alkaline earth metal silicate according to the present invention, when water is added, forms a silicic acid solution having a pH suitable for plant absorption, and is used as a foliar spray. And used as silicate fertilizer.

Hereinafter, the present invention will be described with reference to examples.

[0024]

The present invention will be described specifically with reference to examples.
The determination of the silica and the pH measurement were performed as follows. [Quantitative method of silicic acid] The determination was carried out by the molybdenum ammonium-sodium sulfite method described in the soil nutrient analysis method (published by Yokendo Co., Ltd.) edited by the Soil Nutrient Measurement Committee (in the National Institute of Agriculture and Technology) [Measurement of pH] manufactured by Horiba, Ltd. It was measured using a pH meter type M-7EII.

Example 1 The molar ratio of NaHSO ₄ : Mg ₂ Si ₃ O ₈ was 3.5:
1, 3.2: 1, 2.9: 1, 2.5: 1 and 2.
2: 0.2 mol so as to be 1 NaHSO ₄ · H ₂ O solution 50g to _{Mg 2 Si 3 O 8 · 5H} 2 O respectively 1.00
0, 1.100, 1.200, 1.400 and 1.60
0 g was added and the filtrate was stirred at room temperature for 30 minutes, and the filtrate was filtered and tested. The result is as shown in FIG.

Example 2 0.03, 0.05, 0.07, 0.1, 0.2, 0.
50% 3,0.4 and 0.5 molar NaHSO ₄ solution
All NaHSO to _{g 4: Mg 2 Si 3 O} 8 molar ratio of 2.2: 0.2106,0.3509,0.4913 each of _{Mg 2 Si 3 O 8 · 5H} 2 O to be 1 ,
0.702, 1.404, 2.106, 2.808 and 3.509 g were added, and the mixture was stirred at room temperature for 30 minutes, and the filtrate was subjected to a test. As a comparative example, distilled water 50 was used.
_{Mg 2 Si 3 O 8 · 5H} 2 O was carried out a similar test plus 1.404g to g (1). The result is as shown in FIG.

Example ₃ The molar ratio of NH ₄ HSO ₄ : Na ₂ SiO ₃ is 2.45:
Na ₂ S was added to 50 g of a 0.2 molar NH ₄ HSO ₄ solution so that the ratio became 1,2.4: 1, 2.37: 1 and 2.2: 1.
iO ₃ · 9H ₂ O each 1.160,1.190,1.
20 and 1.30 g were added, and the filtrate was stirred at room temperature for 30 minutes, and the filtrate was tested. The result is as shown in FIG.

Example 4 Assuming that the water of crystallization of CaSiO ₃ .xH ₂ O is 5 molecules, all the molar ratios of NaHSO ₄ : CaSiO ₃ are 2.
0.03 of NaHSO ₄ .H ₂ O to be 8 to 3: 1.
0.108 each of CaSiO ₃ .xH ₂ O was added to 50 g of ₃ , 0.05, 0.07, 0.1 and 0.15 molar solutions.
3, 0.1805, 0.2526, 0.3609 and 0.5414 g were added, and the mixture was stirred at room temperature for 30 minutes, spun down, and then tested on the filtrate. The result is FIG.
It is like.

EXAMPLE 5 The molar ratio of NaHSO ₄ : Na ₂ SiO ₃ was 1.96: 1,
Na ₂ Si was added to 50 g of each 0.1 M NaHSO ₄ solution so as to be 1.9: 1, 1.83: 1 and 1.79: 1.
The O ₃ · 9H ₂ O 0.725,0.750,0.775
And 0.800 g were added, and the mixture was stirred at room temperature for 30 minutes, spun down, and then tested for each filtrate. The result is as shown in FIG.

Data used for charts Example 1

2. Example 2

3. Example 3

4. Example 4

5. Example 5

[0035]

The composition comprising the acid salt and the alkali metal or alkaline earth metal silicate according to the present invention forms a silicic acid solution having a pH suitable for plant absorption when a predetermined amount of water is added. As a foliar spray or a silicic acid fertilizer, it can be fertilized as it is, and it is possible to extract silicic acid more efficiently than the alkaline earth metal silicate which was conventionally insoluble in water.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the molar ratio (x) of NaHSO ₄ : Mg ₂ Si ₃ O ₈ and the SiO ₂ concentration and pH of a reaction product.

FIG. 2 is a graph showing the relationship between the NaHSO ₄ concentration and the SiO ₂ concentration and pH of the reaction product.

FIG. 3 is a graph showing the relationship between the molar ratio (x) of NH ₄ HSO ₄ : Na ₂ SiO ₃ , the SiO ₂ concentration of the reaction product, and the pH.

FIG. 4 is a graph showing the relationship between NaHSO ₄ concentration and SiO ₂ concentration and pH of a reaction product.

FIG. 5: NaHSO ₄ : Na ₂ SiO ₃ molar ratio (x)
4 is a graph showing the relationship between the reaction product and the SiO ₂ concentration and pH of the reaction product.

Claims (2)

(57) [Claims] 1. An ammonium salt of an inorganic monobasic acid and a polybasic acid.
Ammonium salt and part of the acid radical of polybasic acid
A composition comprising 1 to 5 mol of a soluble salt which exhibits an acidity when dissolved in water substituted with potassium metal and 1 mol of a silicate of an alkali metal or alkaline earth metal, wherein the pH of the aqueous solution is from 6 to 9 is in the range of and the composition of the silicate fertilizer capable of producing silicic acid aqueous solution containing 100ppm or more silicate as SiO _2. 2. A soluble salt which exhibits an acidity when dissolved in water is NH ₄ Cl, NH ₄ HSO ₄ , NH ₄ H ₂ P.
O ₄ and claim 1 <br/> composition silicate fertilizer wherein the NaHSO _4. "