JPH0474786A - Production of liquid fertilizer - Google Patents

Abstract

PURPOSE:To obtain a liquid fertilizer without separating crystals even at low temperatures by reacting phosphoric acid with potassium hydroxide and incorporating nitrogen, phosphorus and potassium ingredients into the resultant reaction solution. CONSTITUTION:A liquid fertilizer containing each of nitrogen, phosphorus and potassium is produced. In the production process, phosphoric acid is reacted with potassium hydroxide to provide a reaction solution. Nitrogen, phosphorus and potassium ingredients are then contained in the resultant reaction solution. Thereby, the liquid fertilizer without separating crystals even at low temperatures is obtained by reacting the phosphoric acid with the potassium hydroxide, providing an aqueous solution of potassium phosphate having a high solubility, then adding a nitrogen-containing ingredient as an N ingredient and a phosphorus-containing ingredient as a P ingredient according to the aforementioned production process. As a result, crystals are not separated even at low temperatures in the winter season and the liquid fertilizer can be used as a homogeneous ingredient without anxiety. Thereby, the liquid fertilizer has a great influence on farmers.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing liquid fertilizer.

(Problems to be solved by conventional technology and the invention) Most of the elements necessary for plant growth are sufficiently supplied from air, water, and soil, but three components, nitrogen, phosphorus, and potassium, tend to be deficient. Therefore, these three ingredients must be replenished.

There are various ways to replenish the three ingredients, but
Examples include self-sufficient fertilizers (compost, keifune, plant ash), organic fertilizers (soybean meal, soybean meal, bone meal), and chemical fertilizers.

Chemical fertilizers can be divided into single fertilizers and compound fertilizers, and with the rationalization of agriculture in recent years, the amount used has been expanding from single fertilizers to compound fertilizers.

Further, as compound fertilizers, chemical fertilizers, molded compound fertilizers, adsorbed compound fertilizers, coated compound fertilizers, by-product compound fertilizers, blended fertilizers, liquid compound fertilizers, compound fertilizers for home gardening, and the like are used.

Among them, liquid compound fertilizers are used more and more in recent years because they are liquid and require no dissolving or blending work compared to other fertilizers and are easier to handle.

Liquid compound fertilizer (hereinafter referred to as "liquid fertilizer") refers to a product made into a liquid using ordinary fertilizer or fertilizer raw materials, which prevents precipitation or rot, promotes spreading, and further reduces the formation of nitrate in the soil. This is a general term for materials that contain materials that have the function of suppressing the production of.

Among these, the present invention relates to liquid fertilizers, particularly transparent liquid fertilizers.

Normally, it is best and preferable to use transparent liquid fertilizer, but as the concentration of active ingredients in liquid fertilizer increases, crystals tend to precipitate, so it should be used in a form that does not precipitate crystals. is preferable.

Furthermore, it has the disadvantage that as the temperature of the liquid fertilizer decreases, the precipitation of crystals becomes more pronounced.

Therefore, there is no problem in the summer when the temperature is high, but in the winter when the temperature is low, the solubility of the nitrogen, phosphorus, and potassium components decreases as the temperature decreases, causing crystals to precipitate. Furthermore, the precipitated crystals do not easily dissolve even when heated, which is undesirable because when using a liquid fertilizer, the nozzle for spraying the liquid fertilizer may be clogged and the concentration of the liquid fertilizer may be uneven.

One of the causes of crystal precipitation is that the solubility of the potassium salt as a raw material is lower than that of other nitrogen and phosphorus components.

The present inventors discovered that in order to produce a liquid fertilizer without crystal precipitation, it is possible to produce a transparent liquid fertilizer by increasing the solubility of potassium salt, and completed the present invention. This is what we have come to.

[Means to solve the problem]

As a result of various studies to solve these problems, the present inventors reacted phosphoric acid and potassium hydroxide at a specific temperature to obtain an aqueous solution of phosphate, and then reduced the amount of nitrogen contained in the solution. By adding the phosphorus content as the phosphorus content, we completed a method for producing liquid fertilizer that does not cause crystal precipitation even at low temperatures.

That is, in a method for producing a liquid fertilizer containing each of nitrogen, phosphorus, and potassium, phosphoric acid and potassium hydroxide are reacted to form a reaction liquid, and the reaction liquid contains nitrogen, phosphorus, and potassium. The present invention relates to a method for producing a liquid fertilizer characterized by the following.

[Detailed disclosure of the invention] The present invention will be explained in detail below.

The nitrogen content used here includes urea, ammonium sulfate, lime nitrogen, ammonium nitrate, etc. The phosphorus content used here includes phosphoric acid, diammonium phosphate, diammonium phosphate, etc., and the potassium content used here includes phosphoric acid, ammonium monophosphate, ammonium diphosphate, etc. , potassium sulfate, potassium chloride, potassium carbonate, potassium nitrate, etc. are preferably used, and nitrogen, phosphorus, potassium (hereinafter referred to as N, P,
Liquid fertilizers with various ratios of (abbreviated as) are produced.

However, the potassium content used in the present invention is
Manufacture is performed by the following method.

That is, a major feature was discovered by performing the reaction between phosphoric acid and potassium hydroxide under specific conditions to produce an aqueous solution of potassium phosphate with high solubility.

The reaction between phosphoric acid and potassium hydroxide is a normal neutralization reaction between an acid and an alkali, so it proceeds quickly and generates heat.

The manufacturing method of the present invention will be described below.

That is, in the present invention, a certain amount of phosphoric acid is placed in a reaction vessel, and potassium hydroxide is gradually added while stirring. The reaction between phosphoric acid and potassium hydroxide is an exothermic reaction as described above, and therefore needs to be carried out while being cooled. Since the reaction is completed the moment potassium hydroxide is added to phosphoric acid, it is necessary to stir it well.

In the reaction between phosphoric acid and potassium hydroxide, the weight ratio of PzOs/KzO is preferably in the range of 0.7 to 1.0.

The reaction temperature is 40-90°C, preferably 50-80°C.
and hold for 20-50 minutes. The reaction solution was further diluted with 3
Cool to 0-40'C. Add urea, ammonium sulfate, lime nitrogen, ammonium nitrate, etc. as the N component to the reaction solution kept at 30 to 40°C, and further add monoammonium phosphate, diammonium phosphate, etc. as the P component to the desired ratio. Add the specified amount so that

The reaction pH is 6.0 to 7.0, depending on the N:P ratio.
0 is preferred.

Furthermore, trace ingredients necessary for plant growth are added to the liquid fertilizer.

As trace components, boric acid, manganese sulfate, suspending agents, etc. are added to completely dissolve them.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. In the following, unless otherwise specified, percentages are expressed on a weight basis.

Example 1 166 g of 42% phosphoric acid solution was put into a separable flask with a condenser, stirred, and cooled.
% potassium hydroxide was added at a rate of 30 g/sin and the reaction temperature was maintained at 70''C for 30 minutes.

After that, the temperature was cooled to 40°C, and urea 11 was added to the reaction solution.
1g, monoammonium phosphate 99g, boric acid 1.3g,
Manganese sulfate 1.5g, suspending agent 10.1g, city water 4
63. Ig was added and completely dissolved. After confirming that the additives were completely dissolved, the mixture was filtered, and after filtration, 1000 g of liquid fertilizer with N:P:K=6:1Q:6 was obtained.

The liquid fertilizer obtained in this way was mixed with 10'C15'C
Table 1 shows the results of observing the state of crystal precipitation at 10°C.

Example 2 166 g of 42% phosphoric acid solution was put into the separable flask used in Example 1, stirred, and while cooling, 130 g of 48% potassium hydroxide was added at a rate of 30 g/win to adjust the reaction temperature. Hold at 70"C for 30 minutes.

After that, the temperature was cooled to 40°C, and urea 11 was added to the reaction solution.
5g, monoammonium phosphate 99g, boric acid 1.3g,
Manganese sulfate 1.5g, suspending agent 10.1g, city water 4
1 g of 92° was added and completely dissolved. After confirming that the additive has completely dissolved, filter it, and add 1000g of N after filtration.
: P : K=5 : lQ: 5 liquid fertilizer was obtained.

The liquid fertilizer thus obtained was heated to 10'C15゛C.
Table 1 shows the results of observing the state of crystal precipitation at 10°C.

Example 3 166 g of 42% phosphoric acid solution was put into the separable flask used in Example 1, stirred, and while cooling, 155 g of 48% potassium hydroxide was added at a rate of 30 g/+min to adjust the reaction temperature. It was held at 70°C for 30 minutes.

After that, the temperature was cooled to 40°C, and urea 11 was added to the reaction solution.
5g, monoammonium phosphate 99g, boric acid 1.3g,
Manganese sulfate 1.5g, suspending agent 10.1g, city water 4
671 g was added and completely dissolved. After confirming that the additive is completely dissolved, filter it and add 1000g of N after filtration.
A liquid fertilizer of P:K=5:lQ:6 was obtained.

The liquid fertilizer obtained in this way was heated to 10°C and 15°C.
Table 1 shows the results of observing the state of crystal precipitation at 50°C.

Comparative Example 1 City water 635 was added to the separable flask used in Example 1.
．． 1 g was added and stirred. 1.3 g of boric acid, 1.5 g of manganese sulfate, and 10.1 g of a suspending agent were added to this solution and stirred. After confirming dissolution, the temperature was raised to 40°C. 141g of potassium nitrate and 5g of urea were added to the reaction solution kept at 40°C.
2g of monoammonium phosphate and 174g of monoammonium phosphate were added and completely melted. After making sure that these additives are completely dissolved, add 1000g of 'Q:P: = 6:1 after filtration.
t): 6 liquid fertilizer was obtained. Table 1 shows the results of observing the state of crystal precipitation of the liquid fertilizer thus obtained at 10°C and 15°C.

In Table 1, O indicates that no crystal precipitation is observed, △ indicates that crystal precipitation is slightly observed, and × indicates that a large amount of crystal precipitation is present, making it difficult to use. .

Table 1 [Effects of the Invention] According to the present invention, prevention of crystal precipitation at low temperatures, which has not been achieved with the prior art, is achieved.

That is, phosphoric acid and potassium hydroxide are reacted under specific conditions,
After obtaining a highly soluble aqueous solution of potassium phosphate, N
By adding the nitrogen-containing bone as the component and the phosphorus component as the P component, a method for producing a liquid fertilizer that does not cause crystal precipitation even at low temperatures has been completed.

Therefore, the liquid fertilizer of the present invention does not precipitate crystals even at low temperatures in winter, and can be used with confidence as a uniform ingredient, so it has a significant impact on farmers.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1) In a method for producing a liquid fertilizer containing each of nitrogen, phosphorus, and potassium, phosphoric acid and potassium hydroxide are reacted to form a reaction liquid, and the reaction liquid contains nitrogen, phosphorus, and potassium. A method for producing liquid fertilizer characterized by the following.