JP7320310B2 - Manufacturing method of natural water fertilizer - Google Patents

Description

The present invention relates to a method for producing natural water fertilizer.

Due to changes in seawater temperature due to global warming and the prohibition of ocean dumping of organic waste materials such as sludge, nutrient depletion in the sea, especially phosphorus deficiency, is progressing, hindering the growth of seaweed. there is Along with this, the so-called desertification of the sea is progressing, causing a decrease in the amount of fish caught and a decrease in the amount of aquatic organisms such as abalone and turban shells, which are also high-grade foodstuffs. In addition, aquaculture is also greatly affected.

As an attempt to provide nutrients to the sea, it has been reported that iron and steel slag and humus, which is fermented organic waste, were mixed and buried in the sea. (See Patent Document 1, for example). However, this was intended to be an iron supply source, and could not mitigate or eliminate the problems caused by phosphorus deficiency.

JP 2014-068594 A

An object of the present invention is to provide a method for producing a fertilizer for natural water containing a salt of a phosphoric acid compound that is suitably soluble in natural water.

Such objects are achieved by the present invention described below.
The method for producing a fertilizer for natural water according to the present invention comprises: an object to be treated containing a poorly water-soluble phosphorus compound; and a step of obtaining a soluble salt, which is an alkali metal salt and/or a group 2 element salt of a phosphoric acid compound, by contacting it with a composition containing a soluble substance.

The method for producing a fertilizer for natural water according to the present invention comprises: an object to be treated containing a poorly water-soluble phosphorus compound; contacting a soluble substance in a solid phase to obtain a soluble salt that is an alkali metal salt and/or a group 2 element salt of a phosphoric acid compound.

The method for producing a fertilizer for natural water according to the present invention comprises a material to be treated in which a water-insoluble phosphorus compound is dissolved in an acid or an alkali, an alkali metal and/or a Group 2 element hydroxide and/or salt is brought into contact with a composition containing a reactive ionic substance to obtain a soluble salt that is an alkali metal salt and/or a group 2 element salt of a phosphoric acid compound.

The method for producing a fertilizer for natural water according to the present invention comprises: an object to be treated containing a poorly water-soluble phosphorus compound; contact with a solution containing a soluble substance to obtain a soluble salt that is an alkali metal salt and/or a group 2 element salt of a phosphoric acid compound.

In the method for producing a natural water fertilizer of the present invention, the solution is preferably an aqueous solution.
In the method for producing a natural water fertilizer of the present invention, the solution is preferably a solution containing acid or alkali.

In the method for producing a natural water fertilizer of the present invention, the reactive ionic substance is preferably a hydroxide and/or salt containing Na and/or Ca.

In the method for producing a natural water fertilizer of the present invention, the reactive ionic substance is one selected from the group consisting of Na ₂ CO ₃ , NaOH, CaCO ₃ , Ca(OH) ₂ , CaCl ₂ and NaCl, or Two or more are preferred.

In the method for producing a natural water fertilizer of the present invention, heat treatment is preferably performed in the step of obtaining the soluble salt.

In the method for producing a natural water fertilizer of the present invention, the heating temperature of the heat treatment is preferably 150°C or higher and 1500°C or lower.

In the method for producing fertilizer for natural water according to the present invention, it is preferable that the treatment time of the heat treatment is 1 hour or more and 100 hours or less.

In the method for producing fertilizer for natural water according to the present invention, it is preferable that the material to be treated is sludge ash.

In the method for producing a natural water fertilizer of the present invention, it is preferable that the sparingly soluble phosphorus compound contains at least one of Fe and Al.

In the method for producing a natural water fertilizer of the present invention, the composition preferably contains an alkali metal and/or a group 2 element salt as the reactive ionic substance, and also contains an acidic substance.

The natural water fertilizer of the present invention is a natural water fertilizer containing a soluble salt that is an alkali metal salt and/or group 2 element salt of a phosphoric acid compound,
D ₁ is the elution rate of phosphorus contained in the natural water fertilizer after 5 hours when 1 g of the natural water fertilizer is added to 500 mL of a 3.5% by mass sodium chloride aqueous solution and allowed to stand at 25 ° C. [%], and when the elution rate of phosphorus contained in the natural water fertilizer after 720 hours is D ₂ [%], it is characterized by satisfying the relationship of 1.1 ≤ D ₂ /D ₁ ≤ 100. do.

In the natural water fertilizer of the present invention, the _D2 is preferably 1% or more and 98% or less.
In the natural water fertilizer of the present invention, the sum of the Fe content and the Al content in the natural water fertilizer is X _A [mass%], and the content of the alkali metal in the natural water fertilizer and Group 2 It is preferable to satisfy the relationship of 0.1≦X _B /X _A ≦10, where X _B [mass %] is the sum of the contents of the elements.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a fertilizer for natural water containing a salt of a phosphoric acid compound that is suitably dissolved in natural water, and to provide a method for producing the fertilizer for natural water. .

2 is a graph showing the relationship between the elution rate of a phosphorus component and the number of days elapsed from the addition to an aqueous sodium chloride solution of natural water fertilizers according to Examples 1 to 5 and Comparative Example 1. FIG. FIG. 10 is a graph showing the relationship between the number of days elapsed after addition to an aqueous sodium chloride solution and the elution rate of a phosphorus component for natural water fertilizers according to Examples 6 to 9 and Comparative Example 1; 1 is an X-ray diffraction (XRD) chart of Examples 1 and 6, and sludge ash, which is an object to be treated. FIG. 4 is a diagram showing an example of the relationship between the heating temperature in the heat treatment and the elution rate of phosphorus from the manufactured natural water fertilizer.

Preferred embodiments of the present invention are described in detail below.
[Manufacturing method of natural water fertilizer]
First, the method for producing the natural water fertilizer of the present invention will be described.

The method for producing a fertilizer for natural water according to the present invention comprises a material to be treated containing a phosphorus compound that is sparingly soluble in water (hereinafter also referred to as a "poorly soluble phosphorus compound"), an alkali metal and/or a group 2 element, contacting a composition containing a reactive ionic substance that is a hydroxide and/or salt to obtain a soluble salt that is an alkali metal salt and/or a Group 2 element salt of a phosphoric acid compound; characterized by

Thus, by converting a poorly soluble phosphorus compound into a soluble salt, the solubility in water (natural water) can be improved, and when it is brought into contact with natural water, the phosphorus component is suitable in a dissolved state. can be supplied to Therefore, it can function favorably as a natural water fertilizer (that is, a phosphorus concentration adjusting agent).

On the other hand, when the phosphorus compound is used in a water-poorly soluble state, the phosphorus compound does not substantially dissolve in natural water and cannot function as a fertilizer.

The solubility (elution rate) of fertilizers for natural water is determined by, for example, the composition of soluble salts, the size of the fertilizer for natural waters (particle size, thickness, etc.), the crystalline state (crystal grain size, crystal composition). ratio (crystallinity), etc.), the relationship between the soluble salt and components other than the soluble salt in the fertilizer for natural water (for example, the content of the soluble salt, the content of components other than the soluble salt ratio, size relationship between the soluble salt and components other than the soluble salt, positional relationship between the soluble salt and components other than the soluble salt, etc.). be able to. The conditions for such natural water fertilizers include, for example, the composition of the composition (type and content of reactive ionic substances), reaction conditions (e.g., temperature conditions during reaction, reaction time, Usage amount of the composition, etc.), pretreatment methods and conditions for the reaction (e.g., digestion treatment, purification treatment, etc. for the object to be treated), post-reaction treatment methods and conditions (e.g., pulverization treatment, mixing of multiple components treatment, etc.) can be suitably adjusted.

The object to be treated may be any object as long as it contains a sparingly soluble phosphorus compound. For example, industrial waste such as sludge ash obtained by incinerating sludge, steel slag, and combustion ash from a mushroom bed. Although a substance or the like can be used, the object to be treated is preferably sludge ash.

Sludge ash generally contains a relatively high content of phosphorus, which is a valuable resource, and is produced in large quantities all over the world.

Therefore, by using sludge ash as the material to be treated, resources can be effectively used, and the effect of reducing the amount of industrial waste is particularly large.

In addition, by using sludge ash as a raw material for fertilizers for natural water, it becomes a new method of recycling sludge ash. It is also preferable from the viewpoint of cost reduction of raw materials for fertilizers for natural water.

In general, objects to be treated such as sludge ash contain sparingly soluble phosphorus compounds such as aluminum phosphate and iron phosphate.

In the present invention, "poorly soluble in water" means that the solubility in water is extremely low, for example, the solubility in water at 25° C. is 1×10 ⁻¹⁵ g/100 g water or less.

In the method according to the present invention, a sparingly soluble phosphorus compound is contacted with a composition containing a reactive ionic substance (hydroxide and/or salt of an alkali metal and/or group 2 element) to obtain a soluble salt ( By converting the phosphoric acid compound into an alkali metal salt and/or group 2 element salt), the solubility of the phosphorus compound in water is increased, and it is characterized in that it functions effectively as a fertilizer for natural water.

In the present invention, the term "natural water" includes water that exists collectively in the natural world, such as seas, rivers, lakes, ponds, marshes, etc. In addition, artificial ponds, reservoirs, fishing ponds, etc. , water tanks, fish farms, etc., which are not directly connected to the sea, rivers, lakes, ponds, marshes, etc., and which exist in a closed space. Also, the natural water may be any of fresh water, salt water and brackish water.
Above all, the natural water to which the fertilizer for natural water according to the present invention is applied is preferably seawater.

The ocean is prone to malnutrition, and the so-called desertification of the ocean is progressing. Therefore, when the natural water is seawater, the effects of the present invention are exhibited more remarkably.

By stopping the desertification of the sea, we can restore the ecosystem. For example, by using the fertilizer for natural water according to the present invention, it is possible to supply nutrients to the sea, which improves the growth of seaweed such as kelp and wakame seaweed, and provides a place for fish to grow. In addition, since seaweed also serves as food for abalone and turban shells, the amount of production of high-grade foods such as abalone and turban shells also increases. In other words, it can contribute to economic revitalization of fishing villages.

The form in which the object to be treated containing the sparingly soluble phosphorus compound and the reactive ionic substance are brought into contact is not particularly limited, and examples thereof include those detailed in the following embodiments.

<First Embodiment>
The method for producing a fertilizer for natural water according to the present embodiment includes an object to be treated containing a sparingly soluble phosphorus compound (poorly soluble phosphorus compound in water), a reactive ionic substance (alkali metal and/or Group 2 element (hydroxide and/or salt of ) in solid phase to obtain a soluble salt (alkali metal salt and/or group 2 element salt of phosphoric acid compound). In other words, both the object to be treated and the reactive ionic substance are brought into contact with each other in a solid phase state to allow the desired chemical reaction to proceed and obtain a soluble salt.

As a result, the desired soluble salt can be obtained without using a solvent, so that the burden on the environment is lower and the step of removing the solvent after this step can be omitted.

The sparingly soluble phosphorus compound contained in the object to be treated preferably contains at least one of Fe and Al.

Phosphorus compounds containing at least one of Fe and Al have particularly low solubility in water, and the effect of applying the present invention is more remarkable. In addition, in the process of producing the soluble salt, Fe and Al function as impurities and act favorably in controlling the crystal grain size of the produced soluble salt. As a result, it is possible to more suitably adjust the solubility, sustained release property, etc. of the natural water fertilizer.

Phosphorus compounds containing at least one of Fe and Al are represented by, for example, Fe _x P _y O _z and Al _x P _y O _z (where x, y, and z are each integers of 1 or more). iron phosphate (FePO ₄ ) and aluminum phosphate (AlPO ₄ ) are particularly preferred.
As a result, the effects as described above are exhibited more remarkably.

In addition, the sludge ash generally contains Fe, Al, etc. in a more appropriate ratio together with phosphorus. That is, by using sludge ash as the material to be treated, the effects of the present invention are exhibited more remarkably. From this point of view as well, it is preferable to use sludge ash as the object to be treated.

Reactive ionic substances (hydroxides and/or salts of alkali metals and/or group 2 elements) contain cations and anions, and as cations at least selected from alkali metals and group 2 elements Although it is sufficient if it contains one kind, it preferably contains Na and/or Ca as a cation.

As a result, the soluble salt produced can be the sodium salt and/or calcium salt of the phosphate compound. These salts have more suitable solubility in water, and can exhibit the effects of the present invention more remarkably.

In particular, the reactive ionic substance is _{preferably one or more selected from the group consisting of Na2CO3, NaOH, CaCO3, Ca(OH)2 , CaCl2 and NaCl} .

Thereby, this step can be advanced more efficiently while suppressing the amount of the reactive ionic substance used.

In particular, in this step, it is preferable to use a hydroxide or salt containing Na and a hydroxide or salt containing Ca in combination as the reactive ionic substance.

As a result, the soluble salt produced contains the sodium salt of the phosphate-based compound and the calcium salt of the phosphate-based compound. Since the sodium salt of the phosphate compound and the calcium salt of the phosphate compound have different solubility in water, the solubility in natural water can be more suitably adjusted by combining them. For example, while increasing the elution amount of the phosphorus component (soluble salt) in the initial stage after application to natural water, the phosphorus component (soluble salt) after a relatively long period of time after application to natural water ) can also be relatively high.

More specifically, the calcium salt of the phosphate compound has a lower solubility than the sodium salt of the phosphate compound. By preferentially eluting the sodium salt, the amount of phosphorus component (soluble salt) eluted as a whole is relatively high, and after a relatively long period of time after application to natural water, the solid Elution from the calcium salt of the phosphoric acid compound remaining in the state can ensure the elution amount of the phosphorus component (soluble salt) as a whole.

In the composition containing the reactive ionic substance, when the content of Na is X _Na ' [mol%] and the content of Ca is X _Ca ' [mol%], 0.01 ≤ X _Ca '/X It preferably satisfies the relationship of _Na ′≦100, and more preferably satisfies the relationship of 0.1≦X _Ca ′/X _Na ′≦10.
Thereby, the effect mentioned above is exhibited more notably.

Reactive ionic substances include, in addition to sodium salts and/or calcium salts of phosphoric acid compounds as described above, other reactive ionic substances and other components (for example, alkali metals or secondary ionic substances other than hydroxides or salts of group elements, and nonionic substances).

By adjusting the amount of the reactive ionic substance used with respect to the amount of material to be treated (treated amount), the amount of soluble salt produced can be more suitably adjusted. As a result, the solubility, sustained release properties, etc. of the fertilizer for natural water can be adjusted more favorably.

Although the reactive ionic substance may be in any form, it is preferably particulate in this embodiment.

As a result, for example, by mixing or the like, the reactive ionic substance can be brought into contact with the object to be treated more efficiently, and the reaction in this step can proceed more smoothly. Further, by adjusting the particle size of the reactive ionic substance, the progress of the reaction can be adjusted more appropriately.

When the reactive ionic substance is granular, the average particle size of the reactive ionic substance is preferably 0.1 μm or more and 100 mm or less, more preferably 5 μm or more and 500 μm or less.

As a result, the object to be treated and the reactive ionic substance can be brought into contact with each other more efficiently, and the reactivity can be more effectively enhanced while ensuring safety and ease of operation.

In the present specification, the average particle size refers to the volume average particle size unless otherwise specified.

In the present embodiment, for example, an appropriate amount of water may be added to a composition containing an object to be treated containing a sparingly soluble phosphorus compound and a reactive ionic substance, mixed, and kneaded.

Thereby, the object to be processed and the reactive ionic substance can be brought into contact more efficiently.

Moreover, in the step of obtaining the soluble salt, it is preferable to perform a heat treatment.
As a result, chemical bonds can be formed more efficiently between phosphorus compounds such as phosphoric acid and alkali metals or Group 2 elements while reducing the amount of energy required to produce natural water fertilizers. This process can be performed efficiently in time.

If the mixture of the object to be treated containing the sparingly soluble phosphorus compound and the composition containing the reactive ionic substance contains water, the water may be evaporated prior to the heat treatment.

Further, moisture may be evaporated during the heat treatment.
The heating temperature (maximum temperature) in the heat treatment is preferably 150° C. or higher and 1500° C. or lower, and more preferably 300° C. or higher and 1200° C. or lower.

As a result, the reaction between the phosphorus compound contained in the material to be treated and the reactive ionic substance can be favorably progressed while reducing the amount of energy required for the production of the natural water fertilizer, and the reaction time can be shortened. This step can be performed efficiently.

Further, the heat treatment may be performed while changing the heating temperature. As a result, for example, the reaction between the phosphorus compound contained in the object to be treated and the reactive ionic substance can proceed more favorably, and the shape of the reaction product and the soluble salt in the reaction product The state (for example, the distribution of these when multiple types of soluble salts are included) can be adjusted more appropriately.

In the heat treatment, the heating temperature is held at a plurality of holding temperatures that differ within the above range (e.g., a temperature range within a temperature range of 30 ° C.), and each is heated for a predetermined time (e.g., 10 minutes or more). You may
As a result, the effects as described above are exhibited more remarkably.

In addition, the heat treatment may be performed such that the rate of temperature increase and the rate of temperature decrease are substantially constant, or may be performed such that at least one of the rate of temperature increase and the rate of temperature decrease changes with time. .

In the heat treatment, the temperature increase rate during temperature increase (for example, temperature increase rate from 200° C.) is preferably 1° C./min or more and 50° C./min or less, and 2° C./min or more and 30° C./min or less. is more preferable.

As a result, for example, the reaction between the phosphorus compound contained in the object to be treated and the reactive ionic substance can proceed more favorably, and the shape of the reaction product and the soluble salt in the reaction product The state (for example, the distribution of these when multiple types of soluble salts are included) can be adjusted more appropriately.

In addition, the temperature drop rate during temperature drop (for example, temperature drop rate from 200 ° C.) is preferably 2 ° C./min or more and 50 ° C./min or less, more preferably 3 ° C./min or more and 40 ° C./min or less. preferable.

As a result, for example, the reaction between the phosphorus compound contained in the object to be treated and the reactive ionic substance can proceed more favorably, and the shape of the reaction product and the soluble salt in the reaction product The state (for example, the distribution of these when multiple types of soluble salts are included) can be adjusted more appropriately.

The heat treatment time (heating time at a temperature of 150° C. or higher) is preferably 1 hour or more and 100 hours or less, more preferably 3 hours or more and 18 hours or less.

As a result, this step can be efficiently performed in a shorter time while suppressing the burden on a device (for example, a calcining furnace) that performs heat treatment.

The heat treatment is not particularly limited, but can be performed using an electric furnace, for example. Thereby, the setting and control of the heating temperature, temperature increase rate, temperature decrease rate, etc. can be performed more appropriately.

Note that the heat treatment may be performed using a rotary kiln. Thereby, for example, a large amount of objects to be processed can be continuously subjected to heat treatment.

Further, the atmosphere gas for heat treatment may be any atmosphere, for example, air, inert gas (N ₂ , Ar, etc.), reducing gas such as hydrogen (H ₂ ). but preferably in air.

As a result, an apparatus having a relatively simple structure can be used for the heat treatment, and there is no need to adjust the composition of the atmosphere, etc., and the productivity of natural water fertilizer can be improved.

At the time of heat treatment, it can be converted into various forms of compounds by adjusting the atmosphere gas. Adjustment of the atmosphere gas includes adjustment of the oxygen concentration, adjustment of the pressure of the atmosphere gas, and the like.

An example of the chemical reaction that proceeds in the production method according to the present invention is shown below. In the formula, x, y, z, l, m and n are each integers of 1 or more.

(1) When the poorly soluble phosphorus oxide compound contained in the object to be treated is iron phosphate (FePO ₄ ) (1-1) Reaction with Na ₂ CO ₃ :
_FePO4 + ₃ / _2Na2CO3- > _Na3PO4 + ₃ / _2CO2 +1 _{/ 2Fe2O3
2FePO4 + 2Na2CO3- > Na4P2O6} + _2CO2 + _{Fe2O3 +} 1 _{/ 2O2
FexPyOz + Na2CO3 → NaxPyOz + mCO2 + lFe2O3 _ _}

(1-2) Reaction with _CaCO3 :
_2FePO4 + _3CaCO3 → _Ca3 ( _PO4 ) ₂ + _3CO2 + _{FeCO3
FexPyOz + 3CaCO3 → CaxPyOz + mCO2 + nFe2O3 _}

(2) When the sparingly soluble phosphorus oxide compound contained in the object to be treated is aluminum phosphate (AlPO ₄ ) (2-1) Reaction with Na ₂ CO ₃ :
_{AlPO4 +} 3/ _2Na2CO3- > _Na3PO4 + _{3 / 2CO2} +1/ _{2Al2O3
2AlPO4} + _{2Na2CO3 -} > _{Na4P2O6 + 2CO2} + _Al2O3 + _{1 / 2O2
AlxPyOz + Na2CO3 → NaxPyOz + mCO2 + lAl2O3 _ _}

(2-2) Reaction with _CaCO3 :
_2AlPO4 + _{3CaCO3 → Ca3} ( _PO4 ) ₂ + _3CO2 + _{Al2O3
AlxPyOz + 3CaCO3 → CaxPyOz + mCO2 + nAl2O3 _}

Further, for example, by adjusting the ratio of each component that contributes to the reaction, soluble salts such as calcium-deficient hydroxyapatite, CaHPO ₄ , Ca(H ₂ PO ₄ ) ₂ , Ca ₈ (HPO ₄ ) ₂ , Na It can also be obtained as hydrogen phosphates such as ₂ HPO ₄ and NaH ₂ PO ₄ .

An example of a chemical reaction that yields such a hydrogen phosphate is shown below. In the formula, x, y, a, b, c, d, and e are each integers of 1 or more, and M is a metal element.

_CaxPyOz + _{M (} OH _{) a → CabHcPdOe
NaxPyOz} + _{M (} OH _{) a → NabHcPdOe}

Thus, a natural water fertilizer containing a soluble salt (alkali metal salt and/or group 2 element salt of a phosphate compound) is obtained.

The natural water fertilizer obtained by the method according to the present invention may contain components other than the above-described soluble salts (alkali metal salts and/or group 2 element salts of phosphoric acid compounds).

Such components include, for example, the unreacted portion of the sparingly soluble phosphorus compound contained in the object to be treated, components other than the sparingly soluble phosphorus compound contained in the object to be treated, reaction products thereof, and the like. mentioned.

According to the method of the present invention, the sparingly soluble phosphorus compound contained in the object to be treated can be converted into a highly water-soluble soluble salt.

More specifically, for example, the solubility of sodium phosphate as a soluble salt in water at 20° C. is about 12.1 g/100 g water, and the solubility in water of dicalcium phosphate as a soluble salt is about 0.02 g/100 g water, and the solubility of calcium phosphate in water is about 8.4×10 ⁻¹² g/100 g water, whereas iron phosphate, which is a sparingly soluble phosphorus compound, is substantially The solubility in water of aluminum phosphate, which is a sparingly soluble phosphorus compound, is about 6.3×10 ⁻¹⁹ g/100 g water.

Thus, according to the method of the present invention, the solubility in water can be increased by about 10 ⁵ to 10 ²² times or more. Thereby, the obtained reaction product can be suitably used as a natural water fertilizer.

In addition, according to the method of the present invention, industrial waste such as sludge ash, steel slag, etc. is used as a raw material to produce fertilizer for natural water. It is possible to effectively use the industrial waste that has been in the past, and it is possible to alleviate the above problems, and by using industrial waste as a raw material, it is possible to reduce the manufacturing cost of fertilizer for natural water. .

In addition, the method according to the present invention proposes a new use of sludge ash, iron and steel slag, etc., and a new industry, and it is expected that employment will be created by creating a new industry.

As a method for adjusting the solubility of the sparingly soluble phosphorus compound contained in the object to be treated such as sludge ash, other than the methods described above, for example, the following methods can be used.

That is, first, the water-insoluble phosphorus compound contained in the material to be treated such as sludge ash is contained in biomass, peat, lignite or other low-grade coal (high-grade coal is also possible). The reactivity of the sparingly soluble phosphorus compound can be increased by reacting it with carbon or hydrogen and reducing it.

Then, the phosphorus compound with increased reactivity is reacted with surrounding metals (iron, aluminum, calcium, sodium, etc.) or silicic acid to form sodium phosphate, calcium phosphate, magnesium phosphate, phosphorus silicate compounds, etc. to generate Thereby, the solubility of the sparingly soluble phosphorus compound can be adjusted.

<Second embodiment>
Next, a second embodiment of the method for producing fertilizer for natural water according to the present invention will be described.

A second embodiment of the method for producing fertilizer for natural water according to the present invention will be described below, focusing on differences from the above-described embodiment, and description of the same items will be omitted.

The method for producing a fertilizer for natural water according to the present embodiment includes an object to be treated in which a sparingly soluble phosphorus compound (poorly soluble phosphorus compound in water) is dissolved in an acid or alkali, and a reactive ionic substance (alkali metal and/or or a group 2 element hydroxide and/or salt) to obtain a soluble salt (alkali metal salt and/or group 2 element salt of a phosphoric acid compound).

That is, in the first embodiment described above, the object to be treated containing the poorly soluble phosphorus compound is brought into contact with the composition containing the reactive ionic substance in a solid phase, whereas in the present embodiment, the object to be treated The sparingly soluble phosphorus compound contained in the treated material is dissolved with acid or alkali and reacted as a liquid phase.

By dissolving the poorly soluble phosphorus compounds contained in the object to be treated with acid or alkali, the phosphorus compounds (aluminum phosphate, iron phosphate, etc.) in the object to be treated are eluted as ions containing phosphorus (phosphate ions). can be made

Thereby, the reactivity between the phosphorus compound contained in the object to be processed and the reactive ionic substance can be more effectively improved.

Hereinafter, the case of dissolving the sparingly soluble phosphorus compound contained in the object to be treated with <<2-1>> acid and the case of dissolving with <<2-2>> alkali will be described respectively.

<<2-1>> When dissolving a poorly soluble phosphorus compound with an acid <<2-1-1>>
An object to be treated containing a sparingly soluble phosphorus compound is mixed with an acid.
As a result, the poorly water-soluble phosphorus compound (poorly soluble phosphorus compound) contained in the object to be treated can be suitably dissolved in the acid.

The pH of the liquid phase after dissolving the poorly soluble phosphorus compound in the acid is preferably 1.0 or more and 8.0 or less, more preferably 1.5 or more and 7.0 or less, and 2.0 or more. It is more preferably 6.0 or less.

As a result, for example, while suppressing the amount of the alkaline substance to be used in the treatment for subsequent precipitation of the soluble salt, the above-described effects are exhibited more remarkably. In addition, it is possible to effectively prevent the amount of waste liquid generated in the production of the natural water fertilizer from increasing more than necessary.

The acid used in this step may be, for example, solid or gaseous, but is preferably liquid, and more preferably an aqueous solution.

Thereby, this process can be performed more efficiently, and workability|operativity can be improved further. In addition, post-processing is facilitated.

The acid used in this step includes, for example, sulfuric acid, nitric acid, hydrogen chloride, acetic acid, etc., and one or more selected from these can be used in combination.

As a result, the amount of acid used can be suppressed while ensuring safety, and this step can be performed efficiently.

<<2-1-2>>
A solid reactive ionic substance (alkali metal and /or hydroxides and/or salts of group 2 elements).

In this way, by conducting a liquid-solid phase reaction, the reactivity between the phosphorus compound contained in the object to be treated and the reactive ionic substance can be improved more than in the solid-solid phase reaction. can be effectively improved.

In this step, it is preferable to add and mix the reactive ionic substance in a solid state with the liquid to be treated in which the poorly soluble phosphorus compound is dissolved in the acid.

As a result, the liquid to be processed and the reactive ionic substance can be brought into contact more efficiently, and the reaction efficiency can be further improved.

In this step, the temperature (reaction temperature) of the mixture of the liquid to be treated and the reactive ionic substance is preferably 5° C. or higher and 100° C. or lower, more preferably 10° C. or higher and 60° C. or lower. .
This promotes the reaction and allows the reaction to proceed more efficiently.

<<2-1-3>>
After sufficiently mixing the object to be treated and the reactive ionic substance, a treatment such as concentration and drying is performed, and the solvent is evaporated to obtain a solid containing a soluble salt (e.g., sodium phosphate, calcium phosphate, etc.). can be obtained.

After sufficiently mixing the liquid to be treated and the reactive ionic substance, it is preferable to change the pH of the mixture to precipitate the salt of the phosphoric acid compound.

In the mixture, the produced soluble salt exists in a dissolved state, and by changing the pH of the mixture, the solubility of the salt of the phosphoric acid compound in the mixture is reduced, and the salt of the phosphoric acid compound is dissolved. precipitates out.

Specifically, when the poorly soluble phosphorus compound contained in the object to be treated is dissolved in an acid, the compound containing phosphorus can be precipitated by increasing the pH of the mixture. In particular, phosphorus is precipitated as an alkali metal salt and/or group 2 element salt (eg, sodium phosphate, calcium phosphate, etc.) of a phosphate-based compound.

As a result, in the case of obtaining a fertilizer for natural water by solid-liquid separation of the precipitate, it is more effective to prevent the content of components other than the desired soluble salt in the fertilizer for natural water from becoming too high more than necessary. can be prevented, and the function of the fertilizer for natural water can be enhanced.

Also, for example, by adjusting the precipitation conditions, the grain size of the precipitate (fertilizer for natural water) can be adjusted more favorably.

The alkali used in this step may be, for example, solid or gaseous, but is preferably liquid, and more preferably an aqueous solution.

Thereby, this process can be performed more efficiently, and workability|operativity can be improved further. In addition, post-processing is facilitated.

Examples of the alkali used in this step include metal hydroxides such as NaOH, KOH, Mg(OH) ₂ , Ca(OH) ₂ and Al(OH) ₃ ; metal carbonates such as CaCO ₃ and MgCO ₃ ; , triethylamine, aniline, and the like, and one or more selected from these can be used in combination.

When an alkali is used as the liquid in this step, the pH of the liquid is preferably 10 or higher, more preferably 11 or higher, and even more preferably 12 or higher and 14 or lower.

Thereby, the pH at the end of this step (after the alkali treatment) can be adjusted more appropriately.

Further, the pH of the liquid phase at the end of this step (after the alkali treatment) is preferably 4.0 or more and 11 or less, more preferably 5.0 or more and 10 or less, and 5.5 or more and 9.5. It is more preferably 0 or less.

As a result, the soluble salt can be precipitated more efficiently while preventing the amount of the material used for raising the pH from increasing more than necessary. In addition, it becomes easier to adjust the particle size of the precipitated soluble salt.

<<2-2>> Dissolving Poorly Soluble Phosphorus Compound with Alkali In the following explanation, the differences from "<<2-1> Dissolving Poorly Soluble Phosphorus Compound with Acid" will be mainly explained, and the same The description of the items is omitted.

<<2-2-1>>
An object to be treated containing a sparingly soluble phosphorus compound is mixed with an alkaline solution.
As a result, the poorly soluble phosphorus compound in water (poorly soluble phosphorus compound) contained in the object to be treated can be suitably dissolved in the alkali. On the other hand, heavy metals such as sludge ash contained in the material to be treated are generally difficult to dissolve in alkali. As a result, phosphorus, which is a useful substance that can be used as a fertilizer for natural water, and heavy metals can be preferably separated. Also, final solid waste (industrial waste) can be reduced.

The pH of the liquid phase after dissolving the poorly soluble phosphorus compound in alkali is preferably 6.0 or more and 14 or less, more preferably 7.0 or more and 13 or less, and 8.0 or more and 12 or less. is more preferred.

As a result, for example, while suppressing the amount of the alkaline substance to be used in the treatment for subsequent precipitation of the soluble salt, the above-described effects are exhibited more remarkably. In addition, it is possible to effectively prevent the amount of waste liquid generated in the production of the natural water fertilizer from increasing more than necessary.

The alkali used in this step may be, for example, solid or gaseous, but is preferably liquid, and more preferably an aqueous solution.

Thereby, this process can be performed more efficiently, and workability|operativity can be improved further. In addition, post-processing is facilitated.

Examples of the alkali used in this step include metal hydroxides such as NaOH, KOH, Mg(OH) ₂ , Ca(OH) ₂ and Al(OH) ₃ ; metal carbonates such as CaCO ₃ and MgCO ₃ ; , triethylamine, aniline, and the like, and one or more selected from these can be used in combination.

When an alkali is used as the liquid in this step, the pH of the liquid is preferably 8 or higher, more preferably 11 or higher, and even more preferably 12 or higher and 14 or lower.

As a result, for example, while suppressing the amount of the acidic substance used in the treatment for subsequent deposition of the soluble salt, the above-described effects are exhibited more remarkably. In addition, it is possible to effectively prevent the amount of waste liquid generated in the production of the natural water fertilizer from increasing more than necessary.

<<2-2-2>>
A solid reactive ionic substance (alkali metal and/or group 2 element hydroxide and/or salt ) are brought into contact.

In this step, it is preferable to add and mix the reactive ionic substance in a solid state with the liquid to be treated in which the poorly soluble phosphorus compound is dissolved in alkali.

As a result, the liquid to be processed and the reactive ionic substance can be brought into contact more efficiently, and the reaction efficiency can be further improved.

<<2-2-3>>
After sufficiently mixing the object to be treated and the reactive ionic substance, a treatment such as concentration and drying is performed, and the solvent is evaporated to obtain a solid containing a soluble salt (e.g., sodium phosphate, calcium phosphate, etc.). can be obtained.

After sufficiently mixing the liquid to be treated and the reactive ionic substance, it is preferable to change the pH of the mixture to precipitate the salt of the phosphoric acid compound.

Specifically, when a sparingly soluble phosphorus compound contained in the object to be treated is dissolved in an alkali, the phosphorus-containing compound can be precipitated by lowering the pH of the mixture. In particular, phosphorus is precipitated as an alkali metal salt and/or group 2 element salt (eg, sodium phosphate, calcium phosphate, etc.) of a phosphate-based compound.

As a result, in the case of obtaining a fertilizer for natural water by solid-liquid separation of the precipitate, it is more effective to prevent the content of components other than the desired soluble salt in the fertilizer for natural water from becoming too high more than necessary. can be prevented, and the function of the fertilizer for natural water can be enhanced.

Also, for example, by adjusting the precipitation conditions, the grain size of the precipitate (fertilizer for natural water) can be adjusted more favorably.

The acid used in this step may be, for example, solid or gaseous, but is preferably liquid, more preferably an aqueous solution.

Thereby, this process can be performed more efficiently, and workability|operativity can be improved further. In addition, post-processing is facilitated.

The acid used in this step includes, for example, sulfuric acid, nitric acid, hydrogen chloride, acetic acid, etc., and one or more selected from these can be used in combination.

When an acid is used as a liquid in this step, the pH of the liquid is preferably -1.0 or more and 6.0 or less, more preferably -0.5 or more and 5.0 or less, and 0 or more and 3 It is more preferably 0.0 or less.

Thereby, the pH at the end of this step (after the acid treatment) can be adjusted more appropriately.

The pH of the liquid phase at the end of this step (after acid treatment) is preferably 3.0 or more and 11 or less, more preferably 5.0 or more and 10 or less, and 5.5 or more and 9.0 or less. is more preferable.

As a result, the soluble salt can be precipitated more efficiently while preventing the amount of the material used for raising the pH from increasing more than necessary. In addition, it becomes easier to adjust the particle size of the precipitated soluble salt.

Then, in the present embodiment, the treatment described in the above "<<2-1> Dissolving a sparingly soluble phosphorus compound with an acid" or "<<2-2> Dissolving a sparingly soluble phosphorus compound with an alkali" is performed. After that, the liquid containing the deposited salt of the phosphoric acid compound is subjected to solid-liquid separation, and the solid phase containing the deposited salt of the phosphoric acid compound is separated from the liquid component.

The solid-liquid separation method is not particularly limited, and examples thereof include decantation, filtration, centrifugation, etc., and a plurality of methods may be combined.

Moreover, the separated solid phase may be washed with water or the like, if necessary.
Heat treatment is preferably performed on the separated solid phase.

As a result, chemical bonds can be formed more efficiently between phosphorus compounds such as phosphoric acid and alkali metals or Group 2 elements while reducing the amount of energy required to produce natural water fertilizers. Fertilizer for natural water can be produced efficiently in time.

The heat treatment method and conditions can be the same as the heat treatment method and conditions in the first embodiment described above.

<Third Embodiment>
Next, a third embodiment of the method for producing fertilizer for natural water according to the present invention will be described.

A third embodiment of the method for producing fertilizer for natural water according to the present invention will be described below, focusing on differences from the above-described embodiment, and description of the same items will be omitted.

The method for producing a fertilizer for natural water according to the present embodiment includes an object to be treated containing a sparingly soluble phosphorus compound (poorly soluble phosphorus compound in water), a reactive ionic substance (alkali metal and/or Group 2 element (hydroxide and/or salt of ) to obtain a soluble salt (alkali metal salt and/or group 2 element salt of phosphoric acid compound).

That is, in the above-described embodiment, the reactive ionic substance is brought into contact with the object to be treated containing the poorly soluble phosphorus compound in a solid phase, whereas in the present embodiment, the reactive ionic substance is dissolved It is used as a diluted solution (liquid phase).

Thereby, the reactivity between the phosphorus compound contained in the object to be processed and the reactive ionic substance can be more effectively improved.

The solution containing the reactive ionic substance is preferably an aqueous solution.
Thereby, the reactive ionic substance can be dissolved and ionized more efficiently.

The solution containing the reactive ionic substance is preferably a solution containing acid or alkali.
Thus, by changing the pH of the mixture of the object to be treated and the solution after the reaction in this step is completed, the soluble salt can be precipitated more efficiently.

Moreover, the composition containing a reactive ionic substance preferably contains an alkali metal and/or a salt of a Group 2 element as the reactive ionic substance, and also contains an acidic substance.

This allows the reaction between the object to be treated and the reactive ionic substance to proceed more favorably.
Examples of the acidic substance include hydrogen chloride and sulfuric acid.

The case where the solution contains <<3-1>> acid and the case where the solution contains <<3-2>> alkali will be described.

<<3-1>> Solution Containing Acid The solution is an acid solution containing a reactive ionic substance and an acid.

The pH of the acid solution containing the reactive ionic substance and the acid is preferably -1.0 or more and 6.0 or less, more preferably -0.5 or more and 5.0 or less, and 0 or more and 3 It is more preferably 0.0 or less.
Thereby, the effect mentioned above is exhibited more notably.

The acid used in this step includes, for example, sulfuric acid, nitric acid, hydrogen chloride, acetic acid, etc., and one or more selected from these can be used in combination.

As a result, the amount of acid used can be suppressed while ensuring safety, and this step can be performed efficiently.

By adjusting the content of the reactive ionic substance in the acid solution mixed with the object to be treated, the amount of soluble salt precipitated can be suitably adjusted.

<<3-2>> When Solution Contains Alkali The solution is an alkaline solution containing a reactive ionic substance and an alkali.

The pH of the alkaline solution containing the reactive ionic substance and the alkali is preferably 7.1 or more and 14 or less, more preferably 7.5 or more and 13 or less, and 8.0 or more and 12 or less. is more preferred.

By adjusting the content of the reactive ionic substance in the alkaline solution mixed with the object to be treated, the amount of soluble salt precipitated can be suitably adjusted.

Then, in the present embodiment, after performing the treatment described in "<<3-1>> When the solution contains an acid" or "<<<3-2>> When the solution contains an alkali", the process is performed as described above. The object to be treated is brought into solid phase contact with the solution (acid solution or alkaline solution) containing the obtained reactive ionic substance.

It is preferable to add and mix the object to be treated with the solution containing the reactive ionic substance.
As a result, the solution containing the reactive ionic substance can be brought into contact with the object to be treated more efficiently, and the reaction efficiency can be further improved.

The concentration of the reactive ionic substance in the solution containing the reactive ionic substance is preferably 1% by mass or more, more preferably 5% by mass or more and 50% by mass or less, and 20% by mass or more and 30% by mass. % or less.

The temperature (reaction temperature) of the mixture of the object to be treated and the solution is preferably 5° C. or higher and 100° C. or lower, more preferably 10° C. or higher and 80° C. or lower.
This promotes the reaction and allows the reaction to proceed more efficiently.

After the object to be treated and the solution containing the reactive ionic substance are thoroughly mixed, treatment such as concentration and drying is performed, and the solvent is evaporated to obtain a soluble salt (e.g., sodium phosphate, calcium phosphate, etc.). A solid phase containing

After thoroughly mixing the object to be treated and the solution containing the reactive ionic substance, the pH of the mixture may be changed to precipitate the soluble salt.

Specifically, when the reactive ionic substance is dissolved in an acid, the soluble salt can be precipitated by raising the pH of the mixture.

Also, when the reactive ionic substance is dissolved in an alkali, the soluble salt can be precipitated by lowering the pH of the mixture.

The method and conditions for precipitating the soluble salt by changing the pH of the mixture can be the same as the method and conditions for the precipitation treatment described in the second embodiment.

Then, the liquid containing the precipitated phosphate compound salt is subjected to solid-liquid separation, and the solid phase containing the precipitated phosphate compound salt is separated from the liquid component.

The solid-liquid separation method is not particularly limited, and examples thereof include decantation, filtration, centrifugation, etc., and a plurality of methods may be combined.

Moreover, the separated solid phase may be washed with water or the like, if necessary.
Heat treatment is preferably performed on the separated solid phase.

As a result, chemical bonds can be formed more efficiently between phosphorus compounds such as phosphoric acid and alkali metals or Group 2 elements while reducing the amount of energy required to produce natural water fertilizers. Fertilizer for natural water can be produced efficiently in time.

<Fourth Embodiment>
Next, a fourth embodiment of the method for producing fertilizer for natural water according to the present invention will be described.

A fourth embodiment of the method for producing fertilizer for natural water according to the present invention will be described below, focusing on differences from the above-described embodiment, and the description of the same items will be omitted.

The method for producing a fertilizer for natural water according to the present embodiment includes an object to be treated in which a sparingly soluble phosphorus compound (poorly soluble phosphorus compound in water) is dissolved in an acid or alkali, and a reactive ionic substance (alkali metal and/or or a hydroxide and/or salt of a group 2 element) to obtain a soluble salt (alkali metal salt and/or group 2 element salt of a phosphoric acid compound).

That is, in the above-described embodiment, at least one of the object to be processed and the reactive ionic substance is used in a solid phase, whereas in the present embodiment, the object to be processed and the reactive ionic substance are used in a liquid phase. (solution).

Thereby, the reactivity between the phosphorus compound contained in the object to be processed and the reactive ionic substance can be more effectively improved.

The object to be treated obtained by dissolving the sparingly soluble phosphorus compound with an acid or alkali preferably satisfies the same conditions as described in the second embodiment, and the solution containing the reactive ionic substance preferably satisfies the conditions described in the third embodiment. It is preferable to satisfy the same conditions as those described in the embodiment.

[Natural water fertilizer]
The natural water fertilizer according to the present invention contains a soluble salt that is an alkali metal salt and/or a group 2 element salt of a phosphate compound.

Then, the natural water fertilizer according to the present invention can be suitably produced using the method described above.

In fertilizers for natural water, the soluble salts (alkali metal salts and/or group 2 element salts of phosphoric acid compounds) preferably include salts containing Na or Ca, such as Na _x P _y O _z , Ca _{x Salts} represented by _PyOz (wherein x, _y , and z are each an integer of 1 _or more ₎ are more preferred, and include _Na3PO4 , _Na4P2O7 , _Ca3 ( It is more preferable to contain one or more selected from the group consisting of PO ₄ ) ₂ . Fertilizers for natural water may also contain salts of hydrogen phosphate compounds such as CaHPO ₄ , Ca(H ₂ PO ₄ ) ₂ , NaH ₂ PO ₄ and Na ₂ HPO ₄ .

Fertilizers for natural water may contain components other than the above-described soluble salts (alkali metal salts and/or group 2 element salts of phosphoric acid compounds).

However, the content of components other than soluble salts (alkali metal salts and/or group 2 element salts of phosphoric acid compounds) in natural water fertilizers is preferably 60% by mass or less, and 40% by mass. is more preferably 10% by mass or less.
As a result, the effects as described above are exhibited more remarkably.

In particular, the content of sparingly soluble phosphorus compounds (aluminum phosphate, iron phosphate, etc.) in natural water fertilizers is preferably 60% by mass or less, more preferably 30% by mass or less, and 10% by mass. % or less.
As a result, the effects as described above are exhibited more remarkably.

In addition, the content of soluble salts (alkali metal salts and/or group 2 element salts of phosphoric acid compounds) in natural water fertilizers is preferably 30% by mass or more, and is 70% by mass or more. is more preferable, and 80% by mass or more is even more preferable.
As a result, the effects as described above are exhibited more remarkably.

The natural water fertilizer according to the present invention has a water solubility that can be adjusted. Therefore, by being provided in natural water, the phosphorus component, which is a nutrient for seaweed, etc., can be eluted over a long period of time, and the oligotrophic natural water environment can be eutrophicated, and the effect can be maintained over a long period of time. can be done.

In particular, the natural water fertilizer preferably contains both a sodium salt of a phosphate-based compound and a calcium salt of a phosphate-based compound.

Since the sodium salt of the phosphate compound and the calcium salt of the phosphate compound have different solubility in water, the solubility in natural water can be more suitably adjusted by combining them. For example, while the elution amount of the phosphorus component (soluble salt) in the initial stage after application to natural water is relatively high, the phosphorus component (soluble salt) after a relatively long period of time has passed after application to natural water. salt) can also be relatively high.

When the content of Na in the fertilizer for natural water is X _Na [mol%] and the content of Ca in the fertilizer for natural water is X _Ca [mol%], 0.01 ≤ X _Ca /X _Na ≤ It preferably satisfies the relationship of 100, and more preferably satisfies the relationship of 0.1≦X _Ca /X _Na ≦10.
Thereby, the effect mentioned above is exhibited more notably.

D ₁ is the elution rate of phosphorus contained in the natural water fertilizer after 5 hours when 1 g of the natural water fertilizer is added to 500 mL of a 3.5% by mass sodium chloride aqueous solution and allowed to stand at 25 ° C. [%], when the elution rate of phosphorus contained in the natural water fertilizer after 720 hours is D ₂ [%], it preferably satisfies the relationship of 1.1 ≤ D ₂ /D ₁ ≤ 100, It is more preferable to satisfy the relationship 2.0≦D ₂ /D ₁ ≦80.

As a result, phosphorus can be eluted more favorably over a long period of time, and the effect as a natural water fertilizer can be more favorably exhibited over a long period of time.

Here, _D2 is preferably 1% or more and 98% or less, more preferably 2% or more and 90% or less.

As a result, phosphorus can be eluted more favorably over a long period of time, and the effect as a natural water fertilizer can be more favorably exhibited over a long period of time.

In addition, the sum of the Fe content and the Al content in the natural water fertilizer is X _A [mass%], and the sum of the alkali metal content and the group 2 element content in the natural water fertilizer. When X _B [% by mass], it is preferable to satisfy the relationship of 0.1 ≤ X _B / _XA ≤ 10, and more preferably to satisfy the relationship of 0.2 ≤ X _B / _XA ≤ 5 It is preferable to satisfy the relationship 0.5≦X _B /X _A ≦3.

As a result, phosphorus can be eluted more favorably over a long period of time, and the effect as a natural water fertilizer can be more favorably exhibited over a long period of time.

The natural water fertilizer may be of any shape, but preferably in the form of granules.
This makes handling of natural water fertilizer easier.

When the natural water fertilizer is granular, the particle size can be adjusted depending on the purpose and environment in which the natural water fertilizer is used. By changing the particle size of the natural water fertilizer and the form of administration into the natural water, the elution period and the like can be suitably adjusted.

When the fertilizer for natural water is granular, the average particle diameter thereof is preferably 1 μm or more and 1.0 m or less, and preferably 2 mm or more and 500 mm or less, although it varies depending on the required duration of the natural water fertilizer. is more preferred.

As a result, the rate of dissolution of the natural water fertilizer in the natural water, etc. can be adjusted more favorably.

The mode of administration of the natural water fertilizer into natural water is not particularly limited as long as it is administered in contact with natural water. Fertilizer is mixed with soil or gravel, etc. and applied by laying it on the seabed or the like.

Also, the natural water fertilizer may be applied to natural water in a state of being housed in a container having an opening smaller than the size of the natural water fertilizer.

As a result, it is possible to more reliably prevent the solid fertilizer for natural water from spreading over a wider area than necessary due to the influence of water currents, for example, and failing to obtain a sufficient effect in a desired area. can be done.
As the container, for example, a bag having a mesh may be used.

The constituent material of the bag is not particularly limited, but is preferably a biodegradable polymeric material such as polylactic acid.

In addition, natural water fertilizers are used for structures installed in contact with natural water, such as revetment blocks, wave-dissipating blocks, artificial fish reefs, and embankments, especially large fixed objects made of concrete or entire buildings. Alternatively, it may be used in a state of being contained in a part.

As a result, the natural water fertilizer is more effectively prevented from being washed away by ocean currents, water currents, or the like. In addition, by being contained in concrete or the like, the property of gradually dissolving can be exhibited more effectively, and the effect can be maintained over a long period of time.

The natural water fertilizer may be contained in the entire structure, or may be contained only in a part of the structure (however, the part that can come into contact with natural water).

When the structure is manufactured, it can be made into a structure mixed with natural water fertilizer by mixing it with raw material concrete or the like.

Further, the structure may have a composition containing a fertilizer for natural water adhered to its surface. Also, the natural water fertilizer (the structure) may be buried in the ground and used as long as it can come into contact with natural water.

As a result, for example, it can be suitably applied to a structure that has already been installed in a part that can come into contact with natural water, a structure that has already been manufactured before installation (for example, a structure that is being prepared for installation, etc.). It is also advantageous from the viewpoint of cost and labor. In addition, even when the elution of the phosphorus component progresses and the effect as a fertilizer for natural water is reduced, the fertilizer for natural water can be extended for a desired period by reattaching the composition containing the fertilizer for natural water. can be made In addition, depending on the elution amount of phosphorus components (soluble salts) when applied to natural water and the growth conditions of seaweed, etc., the adhesion amount of the composition containing natural water fertilizer and the composition of the composition can be adjusted. , can create a more favorable environment. Also, in the unlikely event that the eluted amount of the phosphorus component (soluble salt) becomes excessive, the remaining fertilizer for natural water can be recovered relatively easily.

Also, the composition containing the fertilizer for natural water can be suitably attached to the structure serving as the base material by, for example, a coating method.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

For example, the method for producing a natural water fertilizer of the present invention may have steps other than the steps described above (for example, a pretreatment step, an intermediate treatment step, a posttreatment step, etc.).

More specifically, in the method for producing a natural water fertilizer of the present invention, as a pretreatment step, for example, prior to the reaction between the object to be treated and a composition containing a reactive ionic substance, A step of molding the mixture into a predetermined shape (pellet shape, briquette shape) by kneading the composition, compression molding, or the like may be included. Moreover, it may have a pretreatment step of performing purification treatment, digestion treatment, or the like on the object to be treated. In addition, the method for producing a natural water fertilizer according to the present invention may have a step of mixing natural water fertilizers produced under different conditions as an intermediate treatment step or a post-treatment step. Moreover, the method for producing a fertilizer for natural waters of the present invention may have a step of pulverizing the fertilizer for natural waters obtained by the reaction.

Hereinafter, the present invention will be described in detail based on specific examples, but the present invention is not limited to these.

<1> Production of natural water fertilizer (Example 1)
First, sludge ash was prepared as an object to be treated. This sludge ash contained Fe and Al in addition to phosphorus.

Next, 50 mL of water (pure water) was put into a 300 mL Erlenmeyer flask and heated at 80° C. After that, 5.4 g of sodium carbonate as a reactive ionic substance was added into this Erlenmeyer flask and stirred.

Next, 10 g of sludge ash was added to the aqueous sodium carbonate solution, and the mixture was stirred for 40 minutes using a magnetic stirrer. Thus, a 35% by mass sodium carbonate added sample was prepared.

After the stirring was completed, a treatment such as drying was performed to remove the solvent (moisture), and the solid phase portion was subjected to heat treatment at 120° C. for 120 minutes and further dried.

After that, the solid phase portion was subjected to a firing treatment. In the firing process, the temperature is first raised from room temperature to 200°C at a temperature increase rate of 10°C/min, held at 200°C for 2 hours, and then to 800°C (maximum firing temperature) at a temperature increase rate of 20°C/min. minutes, held at 800°C (maximum firing temperature) for 2 hours, then lowered to 200°C at a temperature drop rate of 5°C/min, held at 200°C for 2 hours, and then lowered to room temperature. Rate: Temperature was lowered at 10°C/min.
As a result, a fertilizer for natural water was obtained.

(Example 2)
A natural water fertilizer was produced in the same manner as in Example 1 except that the concentration of the aqueous sodium carbonate solution was changed to 20% by mass.

(Example 3)
A natural water fertilizer was produced in the same manner as in Example 1, except that the concentration of the aqueous sodium carbonate solution was changed to 25% by mass.

(Example 4)
A natural water fertilizer was produced in the same manner as in Example 1, except that the concentration of the aqueous sodium carbonate solution was changed to 30% by mass.

(Example 5)
A natural water fertilizer was produced in the same manner as in Example 1, except that the concentration of the aqueous sodium carbonate solution was changed to 35% by mass.

(Example 6)
First, sludge ash was prepared as an object to be treated. This sludge ash contained Fe and Al in addition to phosphorus.

Next, 100 mL of water (pure water) was put into a 300 mL Erlenmeyer flask and heated at 80° C. Then, 5.4 g of calcium carbonate as a reactive ionic substance was added to this Erlenmeyer flask and stirred.

Next, 10 g of sludge ash was added to the aqueous sodium carbonate solution, and the mixture was stirred for 40 minutes using a magnetic stirrer. Thus, a 20% by mass calcium carbonate-added sample was prepared.

After the stirring was completed, a treatment such as drying was performed to remove the solvent (moisture), and the solid phase portion was subjected to heat treatment at 120° C. for 120 minutes and further dried.

After that, the solid phase portion was subjected to a firing treatment. In the firing process, the temperature is first raised from room temperature to 200°C at a temperature increase rate of 10°C/min, held at 200°C for 2 hours, and then to 800°C (maximum firing temperature) at a temperature increase rate of 20°C/min. minutes, held at 800°C (maximum firing temperature) for 2 hours, then lowered to 200°C at a temperature drop rate of 5°C/min, held at 200°C for 2 hours, and then lowered to room temperature. Rate: Temperature was lowered at 10°C/min.
As a result, a fertilizer for natural water was obtained.

(Example 7)
A natural water fertilizer was produced in the same manner as in Example 6, except that the concentration of calcium carbonate was changed to 25% by mass.

(Example 8)
A natural water fertilizer was produced in the same manner as in Example 6, except that the concentration of calcium carbonate was changed to 30% by mass.

(Example 9)
A natural water fertilizer was produced in the same manner as in Example 6, except that the concentration of calcium carbonate was changed to 35% by mass.

(Comparative example 1)
The sludge ash was directly used as fertilizer for natural water.

The natural water fertilizers of Examples 1 to 9 were analyzed for their components by X-ray diffraction (XRD), and it was found that the natural water fertilizers of Examples 1 to 9 contained sodium phosphate. was confirmed. In addition, the natural water fertilizers obtained in Examples 1 to 9 are all granular, and the average particle size of the natural water fertilizers obtained in Examples 1 to 9 are all 3 mm or more. It was 10 mm or less. In addition, all of the natural water fertilizers obtained in Examples 1 to 9 had a soluble salt (alkali metal salt and/or group 2 element salt of a phosphoric acid compound) content of 10% by mass or more. there were. In addition, the sum of the Fe content and the Al content in the natural water fertilizer is X _A [mass%], and the sum of the alkali metal content and the group 2 element content in the natural water fertilizer. is X _B [% by mass], the natural water fertilizers of Examples 1 to 9 satisfied the relationship of 0.1≦X _B /X _A ≦10.

<2> Evaluation of phosphorus elution rate 1 g of the natural water fertilizer of each example and comparative example produced as described above was added to 500 mL of a 3.5% by mass sodium chloride aqueous solution, and heated to 25 ° C. was left undisturbed.
At this time, the elution rate of phosphorus contained in the natural water fertilizer was measured over 30 days.

FIG. 1 is a diagram showing the relationship between the elution rate of the phosphorus component and the number of days elapsed since the addition of the fertilizers for natural water according to Examples 1 to 5 and Comparative Example 1 to an aqueous sodium chloride solution. FIG. 2 is a graph showing the relationship between the elution rate of the phosphorus component and the number of days elapsed since the addition of the natural water fertilizers according to Examples 6 to 9 and Comparative Example 1 to the aqueous sodium chloride solution.

As is clear from FIGS. 1 and 2, in Comparative Example 1 in which the sludge ash was used as it was, the elution rate of the phosphorus component in 30 days was about 0.5%. It can be seen that both have improved solubility. In addition, it can be seen that the elution rate of phosphorus in the natural water fertilizer can be changed by changing the concentrations of sodium carbonate and calcium carbonate. More specifically, in the range of 15% by mass to 35% by mass performed in Examples 1 to 5, the elution rate can be increased by increasing the concentration of the sodium carbonate aqueous solution, and the elution rate can be increased to about 5% to 50%. The phosphorus elution rate could be adjusted within the range. In addition, in the range of 10% by mass to 35% by mass performed in Examples 6 to 9, the elution rate can be increased by increasing the concentration of the aqueous calcium carbonate solution. The elution rate was adjustable.

In addition, in Examples 1 to 5 in which the sludge ash was reacted using an aqueous sodium carbonate solution, compared to Examples 6 to 9 in which the sludge ash was reacted using an aqueous calcium carbonate solution, the short-term It can be seen that the elution amount of the phosphorus component tends to increase between the two.

In addition, in Examples 6 to 9, in which the sludge ash was reacted using an aqueous calcium carbonate solution, all of them had a longer reaction time than in Examples 1 to 5, in which the sludge ash was reacted using an aqueous sodium carbonate solution. It can be seen that the elution amount of the phosphorus component tends to continue to increase even after the period has elapsed.

Moreover, in each of the above examples, it was confirmed that the elution rate of phosphorus continued to increase even after 30 days had elapsed. Based on this, it is estimated that the phosphorus component can be eluted over a period of two years, and in this case, about 80% of the phosphorus contained in the sludge ash can be eluted.

FIG. 3 shows X-ray diffraction (XRD) charts for the natural water fertilizer of Example 1, the natural water fertilizer of Example 6, and the sludge ash that is the object to be treated. From this figure, it can be seen that in Example 1, Na ₃ PO ₄ was produced as a soluble salt, and in Example 6, Ca ₃ (PO ₄ ) ₂ was produced as a soluble salt.

In addition, 1 g of natural water fertilizer was added to 500 mL of 3.5% by mass sodium chloride aqueous solution and allowed to stand at 25 ° C., and the elution rate of phosphorus contained in the natural water fertilizer after 5 hours was measured. When D ₁ [%] and the elution rate of phosphorus contained in the natural water fertilizer after 720 hours is D ₂ [%], in Examples 1 to 4 and 6 to 9, 2.2 The relationship of ≦D ₂ /D ₁ ≦80 was satisfied, and the value of D ₂ was within the range of 2% or more and 90% or less.

In addition, when sludge ash and sodium carbonate or calcium carbonate were mixed in a solid state and heat-treated, fertilizers for natural water were produced in the same manner as in the above examples, and excellent results were obtained. was gotten.

In addition, the object to be treated (liquid phase), in which the poorly soluble phosphorus compound contained in the sludge ash is dissolved with acid or alkali, is mixed with the solid-state reactive ionic substance (sodium carbonate or calcium carbonate), and the solvent is removed. Fertilizers for natural water use were produced in the same manner as in the above Examples, except that heat treatment was performed after drying, and excellent results were obtained in all cases.

In addition, the object to be treated (liquid phase) in which the poorly soluble phosphorus compound contained in the sludge ash is dissolved with acid or alkali is mixed with the reactive ionic substance (sodium carbonate or calcium carbonate) in aqueous solution (liquid phase). Fertilizers for natural water were produced in the same manner as in the above Examples, except that the solvent was removed, dried, and then heat-treated, and excellent results were obtained in all cases.

Fertilizers for natural water were prepared in the same manner as in the above Examples, except that NaOH, Ca(OH) ₂ , CaCl ₂ and NaCl were used as reactive ionic substances instead of Na ₂ CO ₃ and CaCO ₃ . were produced with excellent results.

Further, the same procedure as in the above examples was performed except that the temperature of the mixture of the sludge ash and the aqueous solution of the reactive ionic substance (sodium carbonate aqueous solution or calcium carbonate aqueous solution) was changed within the range of 5°C or higher and 100°C or lower. We produced fertilizers for natural water using these methods, and obtained excellent results in all cases.

In addition, the heating temperature of the heat treatment is changed within the range of 150 ° C. or higher and 1500 ° C. or lower, and the processing time of the heat treatment (heating time at a temperature of 150 ° C. or higher) is set to 1 hour or more and 100 hours or less. Fertilizers for natural water use were produced in the same manner as in the above examples, except for the change in , and excellent results were obtained in all cases.

As an aqueous solution containing a reactive ionic substance, an aqueous solution containing sodium carbonate and calcium carbonate is used, and the content of Na in the aqueous solution (composition) is X _Na ' [mol%], and the content of Ca is X. A natural water fertilizer was produced in the same manner as in each of the above examples, except that the value of X _Ca '/X _Na ' was changed within the range of 0.01 to 100 when _Ca ' [mol%]. Excellent results were obtained in all cases. In addition, when the content of Na in the fertilizer for natural water obtained with this paper is X _Na [mol%] and the content of Ca in the fertilizer for natural water is X _Ca [mol%], X _Ca /X _Na was a value within the range of 0.01 or more and 100 or less.

Same as Example 1 except that sodium hydroxide was used as a 20% by mass aqueous solution instead of sodium carbonate as the reactive ionic substance, and the firing temperature (maximum firing temperature) was variously changed in the range of 400 ° C. to 900 ° C. A natural water fertilizer is produced in the same manner, and the phosphorus elution rate of the natural water fertilizer is measured in the same manner as described above. Fig. 4 shows the relationship between the elution rate of phosphorus and the

As is clear from FIG. 4, even if the same material is used, the elution rate of phosphorus from the obtained natural water fertilizer differs depending on the production conditions (here, the calcination temperature).

The method for producing a fertilizer for natural water according to the present invention comprises: an object to be treated containing a poorly water-soluble phosphorus compound; contact with a composition containing a soluble substance to obtain a soluble salt that is an alkali metal salt and/or a group 2 element salt of a phosphoric acid compound. In addition, the natural water fertilizer of the present invention is a natural water fertilizer containing a soluble salt that is an alkali metal salt and/or group 2 element salt of a phosphoric acid compound. When added to a 3.5 mass% sodium chloride aqueous solution and allowed to stand at 25 ° C., the elution rate of phosphorus contained in the natural water fertilizer after 5 hours is D ₁ [%], and after 720 hours, natural When the elution rate of phosphorus contained in the water fertilizer is D ₂ [%], the relationship 1.1≦D ₂ /D ₁ ≦100 is satisfied. Therefore, it is possible to provide a fertilizer for natural water containing a salt of a phosphoric acid compound that is suitably soluble in natural water. Therefore, the method for producing a natural water fertilizer and the natural water fertilizer of the present invention have industrial applicability.

Claims (6)

An object to be treated containing a phosphorus compound that is sparingly soluble in water is brought into contact with a composition containing a reactive ionic substance that is a hydroxide and/or salt of an alkali metal and/or a Group 2 element, obtaining a soluble salt that is an alkali metal salt and/or a group 2 element salt of an acid compound;
A method for producing a natural water fertilizer, wherein in the step of obtaining the soluble salt, heat treatment is performed at a heating temperature of 150° C. or higher and 900° C. or lower for a treatment time of 3 hours or longer and 100 hours or shorter. An object to be treated containing a poorly water-soluble phosphorus compound is brought into contact with a reactive ionic substance that is a hydroxide and/or salt of an alkali metal and/or a group 2 element in a solid phase, and phosphoric acid is obtaining a soluble salt that is an alkali metal salt and/or a group 2 element salt of a compound of the
A method for producing a natural water fertilizer, wherein in the step of obtaining the soluble salt, heat treatment is performed at a heating temperature of 150° C. or higher and 900° C. or lower for a treatment time of 3 hours or longer and 100 hours or shorter. A composition containing an object to be treated obtained by dissolving a poorly water-soluble phosphorus compound with an acid or alkali, and a reactive ionic substance that is a hydroxide and/or salt of an alkali metal and/or a Group 2 element. to obtain a soluble salt that is an alkali metal salt and/or a group 2 element salt of a phosphoric acid compound,
A method for producing a natural water fertilizer, wherein in the step of obtaining the soluble salt, heat treatment is performed at a heating temperature of 150° C. or higher and 900° C. or lower for a treatment time of 3 hours or longer and 100 hours or shorter. An object to be treated containing a phosphorus compound that is poorly soluble in water is brought into contact with a solution containing a reactive ionic substance that is a hydroxide and/or salt of an alkali metal and/or a Group 2 element, and phosphoric acid is obtaining a soluble salt that is an alkali metal salt and/or a group 2 element salt of a compound of the
A method for producing a natural water fertilizer, wherein in the step of obtaining the soluble salt, heat treatment is performed at a heating temperature of 150° C. or higher and 900° C. or lower for a treatment time of 3 hours or longer and 100 hours or shorter. Satisfying the relationship of 0.01 ≤ X _Ca /X _Na ≤ 100, where X _Na [mol%] is the content of Na and X _Ca [mol%] is the content of Ca in the natural water fertilizer The method for producing a natural water fertilizer according to any one of claims 1 to 4, characterized by: D ₁ is the elution rate of phosphorus contained in the natural water fertilizer after 5 hours when 1 g of the natural water fertilizer is added to 500 mL of a 3.5% by mass sodium chloride aqueous solution and allowed to stand at 25 ° C. [%], and when the elution rate of phosphorus contained in the natural water fertilizer after 720 hours is D ₂ [%], it is characterized by satisfying the relationship of 1.1 ≤ D ₂ /D ₁ ≤ 100. The method for producing a natural water fertilizer according to any one of claims 1 to 4.