CN104310341B - A kind of method for preparing ammonium dihydrogen phosphate by-product grapefruit special complex fertilizer - Google Patents

Abstract

The invention discloses a method for preparing special compound fertilizer for pomelo trees produced by ammonium dihydrogen phosphate. The method comprises the following steps: raw material preparation, preparation of ammonium dihydrogen phosphate, addition of filtrate elements, and drying. High-purity ammonium dihydrogen phosphate is prepared by reacting phosphoric acid with urea and ammonia water, and at the same time, the mother liquor produced by the reaction is processed and adjusted to prepare a compound fertilizer suitable for the growth of pomelo trees, which reduces the waste of resources and has certain environmental protection value and Economic Value.

Description

A method for preparing ammonium dihydrogen phosphate by-product special compound fertilizer for pomelo trees

technical field

The invention relates to the technical field of fertilizers, in particular to a method for preparing ammonium dihydrogen phosphate by-product special compound fertilizer for pomelo trees.

Background technique

Grapefruit tree, Rutaceae. The evergreen trees have large, thick leaves with large, heart-shaped leaves. Flowers are large, often clustered into racemes. The fruit is large, round, oblate or broadly obovate, pale yellow or orange when ripe. The pericarp is thick, has large oil glands, and is not easy to peel off. The pulp is white or red, called pomelo. The fruit tastes sweet and sour, ripe at the end of autumn, resistant to storage, and has a single seed embryo. The fruit is eaten raw or processed, and the peel can be preserved. Fragrant oil can be extracted from flowers, leaves, and peels, and high-quality pomelo is inseparable from good fertilizers. The main nutrients absorbed by pomelo trees are nitrogen, phosphorus, potassium, calcium, magnesium, etc., but the amount of nitrogen, phosphorus, and potassium in ordinary fertilizers The utilization rate is very low. In general compound fertilizers, the nitrogen utilization rate is 20%-40%, phosphorus is only about 20%, and potassium can reach more than 30%. It can be seen that the utilization rate of phosphorus is the lowest in the current season, and the utilization rate of nitrogen and potassium is equal. Ordinary fertilizers have problems such as high element loss, large soil environmental pollution, and high cost. Therefore, the specificity of compound fertilizers is of great significance for different crops.

At present, there is also a preparation technology for compound fertilizers for crops, but no technical solutions for compound fertilizers in a compound state that match elements according to the research on the elements required by crops for different crop varieties have not been found in relevant patent documents and open literature Exist, also do not find the technical scheme that by-products special compound fertilizer of pomelo tree occurs in the process of preparing ammonium dihydrogen phosphate.

Therefore, the present inventor adjusts the entire production process and parameter side effects on the absorption rate of the required elements by crops while improving the purity of the ammonium dihydrogen phosphate product prepared from grapefruit tree through a large amount of research and practice. Produce special high-efficiency compound fertilizers suitable for grapefruit trees.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention provides a special compound compound for pomelo tree that has less element loss, low environmental pollution, reasonable element mix, and improves the purity of ammonium dihydrogen phosphate product while the secondary production capacity enables the pomelo tree to fully absorb the elements. Fertilizer preparation method.

The present invention is achieved through the following technical solutions:

A method for preparing ammonium dihydrogen phosphate by-product special compound fertilizer for pomelo trees, the method comprising the following steps:

a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.4-1.6, the concentration of phosphoric acid is 70-74%, increase the temperature to 90-120 °C at a heating rate of 6 °C/min, and stir for 28 minutes. Obtain slurry, separate and obtain urea phosphate;

b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.2 to 3.6 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer. Filter and separate to obtain ammonium dihydrogen phosphate;

C, filtrate element addition: in the filtrate that separates, add potassium element and the required trace element compound of pomelo tree to obtain the mother liquor of grapefruit tree special-purpose compound fertilizer;

d, drying: the mother liquor is placed in a drier, the temperature is controlled at 38°C, after drying for 24min, the water content is controlled to be 4% to obtain the special fertilizer for pomelo trees.

The reaction of phosphoric acid and urea in the step a is the reaction of phosphoric acid solution and urea solid, the molar ratio of phosphoric acid and urea is 2:1.4, and the concentration of phosphoric acid is 72%.

In the step c, the trace element compound is a chelate compound of calcium and magnesium, and the content of nitrogen element in the mother liquor of grapefruit tree special compound fertilizer is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium is 4.3%.

In the step d, the nitrogen element content of the grapefruit tree special compound fertilizer is 15.4%, the calcium element content is 3.8%, the magnesium element content is 4.1%, the phosphorus pentoxide content is 7.3%, and the potassium element content is 8.1%. .

The special compound fertilizer for pomelo trees in the step d is a compound compound fertilizer in a chemical state.

In the step d, the special compound fertilizer for pomelo tree contains the following nitrogen, phosphorus and potassium compound state structural formula in its composition:

Wherein, the dotted line between the carbon atom and the oxygen atom indicates that there is a coordination bond between the C atom and the O atom.

The beneficial effects of the present invention are: while preparing high-purity ammonium dihydrogen phosphate through the reaction of phosphoric acid and urea, the remaining slurry can also be prepared into the special compound fertilizer required by grapefruit trees through processes such as element addition and drying, and the mother liquor can be obtained In order to make full use of it and reduce the cost, according to the research and analysis of the element content required by the pomelo tree and the absorption rate of the pomelo tree to the element, the prepared compound fertilizer meets the requirements of the pomelo tree to the greatest extent, reducing the The waste of elements avoids the soil pollution problem caused by the residue of compound fertilizer.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the examples, but the scope of protection is not limited to the description.

Description of the reaction principle:

First, by adjusting the reaction parameters of phosphoric acid and urea, urea phosphate was prepared. Urea phosphate can continue to react with phosphoric _acid to form H _{2 NCONH 3} ⁺ and H ₂ PO ₄ ^{- .} Formed at a temperature of 85-120°C Intermediate ion and dihydrogen phosphate, after adding excess ammonium ion, dihydrogen phosphate reacts with ammonium ion to form ammonium dihydrogen phosphate, which is precipitated, and reacts with ammonium ion in the intermediate ion after adding potassium ion to form Then add calcium and magnesium chelates to form a compound fertilizer, which is dried to obtain a special compound fertilizer for pomelo trees. The reaction equation of above-mentioned reaction principle is as follows:

Chemical reaction equation one:

H ₂ PO ₃ +CO(NH ₂ ) ₂ —CO(NH ₂ ) ₂ ·H ₃ PO ₄

Chemical reaction equation two:

CO(NH ₂ ) ₂ ·H ₃ PO ₄ —H ₂ NCONH ₃ ⁺ +H ₂ PO ₄ ^-

Chemical reaction equation three:

H ₂ PO ₄ ^- +NH ₄ ⁺ —NH ₄ H ₂ PO ₄

Chemical reaction equation four:

Chemical reaction equation five:

The present invention will be further elaborated below in conjunction with specific embodiments.

Embodiment one

a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.4, the concentration of phosphoric acid is 70%, rise to 90°C at a heating rate of 6°C/min, stir and react for 28min, and prepare a slurry, separate Obtain urea phosphate, the reaction of phosphoric acid and urea is the reaction of phosphoric acid solution and urea solid;

b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.6 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer, filtered, Separation obtains ammonium dihydrogen phosphate;

c, filtrate element addition: add potassium element and pomelo tree required trace element compound to obtain the mother liquor of grapefruit tree special compound fertilizer in the filtrate obtained by separation, trace element compound is the chelate compound of calcium, magnesium, grapefruit tree special compound fertilizer The content of nitrogen element in the mother liquor is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium element is 4.3%;

d, drying: mother liquor is placed in drier, temperature is controlled at 38 ℃, after drying 24min, control water content is 4% to obtain grapefruit tree special fertilizer, the nitrogen element content of grapefruit tree special compound fertilizer is 15.4%, calcium element content The content of magnesium element is 3.8%, the content of magnesium element is 4.1%, the content of phosphorus pentoxide is 7.3%, and the content of potassium element is 8.1%.

Embodiment two

a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.5, the concentration of phosphoric acid is 71%, rise to 95°C at a heating rate of 6°C/min, stir and react for 28min, and prepare a slurry, separate Obtain urea phosphate, the reaction of phosphoric acid and urea is the reaction of phosphoric acid solution and urea solid;

b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.5 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer, filtered, Separation obtains ammonium dihydrogen phosphate;

c, filtrate element addition: add potassium element and pomelo tree required trace element compound to obtain the mother liquor of grapefruit tree special compound fertilizer in the filtrate obtained by separation, trace element compound is the chelate compound of calcium, magnesium, grapefruit tree special compound fertilizer The content of nitrogen element in the mother liquor is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium element is 4.3%;

d, drying: mother liquor is placed in drier, temperature is controlled at 38 ℃, after drying 24min, control water content is 4% to obtain grapefruit tree special fertilizer, the nitrogen element content of grapefruit tree special compound fertilizer is 15.4%, calcium element content The content of magnesium element is 3.8%, the content of magnesium element is 4.1%, the content of phosphorus pentoxide is 7.3%, and the content of potassium element is 8.1%.

Embodiment three

a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.6, the concentration of phosphoric acid is 73%, rise to 90-120 °C at a heating rate of 6 °C/min, and stir for 28 minutes to prepare a slurry , separate and obtain urea phosphate, the reaction of phosphoric acid and urea is the reaction of phosphoric acid solution and urea solid;

b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.4 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer, filtered, Separation obtains ammonium dihydrogen phosphate;

c, filtrate element addition: add potassium element and pomelo tree required trace element compound to obtain the mother liquor of grapefruit tree special compound fertilizer in the filtrate obtained by separation, trace element compound is the chelate compound of calcium, magnesium, grapefruit tree special compound fertilizer The content of nitrogen element in the mother liquor is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium element is 4.3%;

d, drying: mother liquor is placed in drier, temperature is controlled at 38 ℃, after drying 24min, control water content is 4% to obtain grapefruit tree special fertilizer, the nitrogen element content of grapefruit tree special compound fertilizer is 15.4%, calcium element content The content of magnesium element is 3.8%, the content of magnesium element is 4.1%, the content of phosphorus pentoxide is 7.3%, and the content of potassium element is 8.1%.

Embodiment four

a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.4, the concentration of phosphoric acid is 74%, rise to 100°C at a heating rate of 6°C/min, stir and react for 28min, and prepare a slurry, separate Obtain urea phosphate, the reaction of phosphoric acid and urea is the reaction of phosphoric acid solution and urea solid;

b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.3 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer, filtered, Separation obtains ammonium dihydrogen phosphate;

c, filtrate element addition: add potassium element and pomelo tree required trace element compound to obtain the mother liquor of grapefruit tree special compound fertilizer in the filtrate obtained by separation, trace element compound is the chelate compound of calcium, magnesium, grapefruit tree special compound fertilizer The content of nitrogen element in the mother liquor is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium element is 4.3%;

d, drying: mother liquor is placed in drier, temperature is controlled at 38 ℃, after drying 24min, control water content is 4% to obtain grapefruit tree special fertilizer, the nitrogen element content of grapefruit tree special compound fertilizer is 15.4%, calcium element content The content of magnesium element is 3.8%, the content of magnesium element is 4.1%, the content of phosphorus pentoxide is 7.3%, and the content of potassium element is 8.1%.

Embodiment five

a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.4, the concentration of phosphoric acid is 74%, rise to 105°C at a heating rate of 6°C/min, stir and react for 28min, and prepare a slurry, separate Obtain urea phosphate, the reaction of phosphoric acid and urea is the reaction of phosphoric acid solution and urea solid;

b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.3 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer, filtered, Separation obtains ammonium dihydrogen phosphate;

c, filtrate element addition: add potassium element and pomelo tree required trace element compound to obtain the mother liquor of grapefruit tree special compound fertilizer in the filtrate obtained by separation, trace element compound is the chelate compound of calcium, magnesium, grapefruit tree special compound fertilizer The content of nitrogen element in the mother liquor is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium element is 4.3%;

d, drying: mother liquor is placed in drier, temperature is controlled at 38 ℃, after drying 24min, control water content is 4% to obtain grapefruit tree special fertilizer, the nitrogen element content of grapefruit tree special compound fertilizer is 15.4%, calcium element content The content of magnesium element is 3.8%, the content of magnesium element is 4.1%, the content of phosphorus pentoxide is 7.3%, and the content of potassium element is 8.1%.

Embodiment six

a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.6, the concentration of phosphoric acid is 74%, rise to 120°C at a heating rate of 6°C/min, stir and react for 28min, and prepare a slurry, separate Obtain urea phosphate, the reaction of phosphoric acid and urea is the reaction of phosphoric acid solution and urea solid;

b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.4 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer, filtered, Separation obtains ammonium dihydrogen phosphate;

c, filtrate element addition: add potassium element and pomelo tree required trace element compound to obtain the mother liquor of grapefruit tree special compound fertilizer in the filtrate obtained by separation, trace element compound is the chelate compound of calcium, magnesium, grapefruit tree special compound fertilizer The content of nitrogen element in the mother liquor is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium element is 4.3%;

d, drying: mother liquor is placed in drier, temperature is controlled at 38 ℃, after drying 24min, control water content is 4% to obtain grapefruit tree special fertilizer, the nitrogen element content of grapefruit tree special compound fertilizer is 15.4%, calcium element content The content of magnesium element is 3.8%, the content of magnesium element is 4.1%, the content of phosphorus pentoxide is 7.3%, and the content of potassium element is 8.1%.

The products and technical effects of the present invention will be further described below in conjunction with specific experimental examples.

Experimental example one

Embodiment one of the present invention, embodiment two, embodiment three, embodiment four, embodiment five, embodiment six, the ammonium dihydrogen phosphate product prepared in the present invention is detected by the standard of GB25569-2010, and detection result is as shown in table 1 Show:

Table 1 The purity detection of ammonium dihydrogen phosphate product of the present invention

Ammonium dihydrogen phosphate Eligibility criteria Embodiment one Embodiment two Embodiment three Embodiment four Embodiment five Embodiment six

Purity≥% 96 98.3 98.5 98.3 98.1 98 98.2 Moisture ≤% 0.5 0.39 0.41 0.42 0.4 0.43 0.41

As can be seen from Table 1, the ammonium dihydrogen phosphate produced by the technical solution of the present invention has not only reached the qualified standard, but also has a higher purity of the product, which shows that the method has significantly improved the ammonium dihydrogen phosphate product.

Experimental example two

According to the absorption of the pomelo tree's element content and the growth of the pomelo tree, a comparison test was made between the special compound fertilizer for the pomelo tree and the common compound fertilizer. Take 9 pomelo trees as test objects, respectively labeled as A, B, C, D, E, F, G, H, I, apply common fertilizer to pomelo trees with three labels of A, B, and C, and apply common fertilizer to D, E , F, G, H, I and other six labels of pomelo tree seedlings are applied respectively to the pomelo tree special fertilizer prepared in embodiment one, embodiment two, embodiment three, embodiment four, embodiment five, embodiment six , and the comparative experimental results are shown in Table 2:

Table 2 Comparison of elemental absorption rate of pomelo trees and their effects on growth of pomelo trees with ordinary compound fertilizer and special compound fertilizer for pomelo trees

As can be seen from the above table, the special compound fertilizer for pomelo trees prepared by the present invention can be fully absorbed by pomelo trees, and is also rich in nutrients needed by pomelo trees such as Ca and Me, which provides a guarantee for the normal growth of pomelo trees, improves Improve the growth of pomelo trees, increase the output of pomelo, thereby improving economic benefits.

Claims (3)

1. a method for preparing ammonium dihydrogen phosphate by-product grapefruit tree special compound fertilizer, is characterized in that, the method may further comprise the steps: a. Raw material preparation: first mix phosphoric acid and urea in a molar ratio of 2:1.4-1.6, the concentration of phosphoric acid is 70-74%, increase the temperature to 90-120 °C at a heating rate of 6 °C/min, and stir for 28 minutes. Obtain slurry, separate and obtain urea phosphate; b. Preparation of ammonium dihydrogen phosphate: Slowly add ammonia water to the slurry containing urea phosphate to control the pH value to 3.2-3.6 and fully stir to obtain a slurry containing nitrogen and phosphorus. The slurry is cooled to 24°C in a cooling crystallizer , filtering and separating to obtain ammonium dihydrogen phosphate; C, filtrate element addition: in the filtrate that separates, add potassium element and the required trace element compound of pomelo tree to obtain the mother liquor of grapefruit tree special-purpose compound fertilizer; d, drying: mother liquor is placed in drier, temperature is controlled at 38 ℃, after drying for 24min, control moisture content to be 4% to obtain grapefruit tree special fertilizer; The reaction of phosphoric acid and urea in the step a is the reaction of phosphoric acid solution and urea solid, phosphoric acid and urea are mixed in a molar ratio of 2:1.4, and the concentration of phosphoric acid is 72%; In the step c, the trace element compound is a chelate compound of calcium and magnesium, and the content of nitrogen element in the mother liquor of grapefruit tree special compound fertilizer is 15.7%, phosphorus pentoxide is 7.6%, potassium element is 8.2%, calcium element is 4.5%, magnesium is 4.3%; In the step d, the nitrogen element content of the grapefruit tree special compound fertilizer is 15.4%, the calcium element content is 3.8%, the magnesium element content is 4.1%, the phosphorus pentoxide content is 7.3%, and the potassium element content is 8.1% . 2. the method for preparing ammonium dihydrogen phosphate byproduct pomelo tree special compound fertilizer according to claim 1, is characterized in that: the pomelo tree special compound fertilizer is compound state compound fertilizer in the described step d. 3. the method for preparing ammonium dihydrogen phosphate by-product grapefruit tree special compound fertilizer according to claim 1, is characterized in that: in the described step d, grapefruit tree special compound fertilizer contains following nitrogen, phosphorus and potassium compound state structural formula in its composition: Wherein, the dotted line between the carbon atom and the oxygen atom indicates that there is a coordination bond between the C atom and the O atom.