CN111533099A - Production method of water-soluble monoammonium phosphate - Google Patents

Abstract

The invention relates to a production method of water-soluble monoammonium phosphate, and belongs to the technical field of clean processing and utilization of phosphate rock. A production method of water-soluble monoammonium phosphate, comprising the following steps: a. using nitric acid and phosphate rock to mix, reacting at 30-70 DEG C for 0.5-2 hours, and then separating solid and liquid to obtain an acid hydrolyzed solution; b. and to pH 6.5～8, solid-liquid separation to obtain solid phase I and liquid phase I; c. Mix solid phase I and sulfuric acid solution, react at 30～70 ℃ for 0.3～2h, and separate solid and liquid to obtain solid phase II and Liquid phase II: neutralize liquid phase II to a pH of 4.0-4.5, and then separate the solid and liquid to obtain solid phase III and liquid phase III; wherein, the liquid phase III is water-soluble monoammonium phosphate after processing. The method of the invention completely separates phosphorus and calcium in the phosphate rock, greatly improves the utilization rate of elements such as calcium and phosphorus, and can directly produce water-soluble monoammonium phosphate.

Description

A kind of production method of water-soluble monoammonium phosphate

technical field

The invention relates to a production method of water-soluble monoammonium phosphate, and belongs to the technical field of clean processing and utilization of phosphate rock.

Background technique

Phosphate resource is an important strategic resource of the country and the material basis of the phosphorus chemical industry. It is non-renewable. my country is rich in phosphate rock, but more than 80% of it is medium and low-grade phosphate rock that is difficult to use directly.

The processing and utilization of phosphate rock mainly include thermal method and wet method, among which wet method accounts for the vast majority. The wet process mainly includes the hydrochloric acid method, the sulfuric acid method and the nitric acid method. The vast majority of enterprises in China produce phosphoric acid and downstream phosphate products through the sulfuric acid process. However, every ton of phosphoric acid produced (calculated as P ₂ O ₅ ) will discharge 5 to 5.5 tons of waste phosphogypsum, with an annual discharge of 88 million tons. Hundreds of millions of tons are stored, and the comprehensive utilization rate is less than 30%. Phosphogypsum is mainly discharged in the open air, occupying a lot of land and polluting the ecological environment. Therefore, there is an urgent need to develop clean processing technologies for phosphorus resources, reduce solid waste emissions during production and utilization, and achieve green, clean and sustainable development of the phosphorus chemical industry. Hydrochloric acid wet-process phosphoric acid is hardly affected by raw materials, has a wide range of use, and does not produce phosphogypsum solid waste. However, the processing of phosphate rock by the hydrochloric acid method is extremely corrosive, requires high equipment material, and requires a large investment in equipment; and the by-product calcium chloride is difficult to use, and the production and application limitations are very obvious. Emissions issues. Compared with the sulfuric acid method and the hydrochloric acid method, the treatment of phosphate rock with nitric acid is more meaningful and promising. Nitric acid plays a dual role in the process of treating phosphate rock. It uses the chemical energy of nitric acid to decompose the phosphate rock, and itself can be converted into nitrogen fertilizer for use to improve the utilization rate of raw materials. And the nitric acid method does not produce solid waste and is a clean processing technology.

Calcium ammonium nitrate is an excellent agricultural chemical fertilizer containing nitrogen and calcium. The production process of calcium ammonium nitrate mainly includes neutralization method and nitrophosphate by-product method. The process flow of the by-product method of nitrophosphate fertilizer is as follows: the acid hydrolyzate of phosphate rock decomposed by nitric acid is crystallized by freezing, and Ca(NO ₃ ) ₂ ·4H ₂ O is precipitated. After the precipitated calcium nitrate is dissolved in water, it is neutralized by liquid ammonia or ammonia water and then filtered. The filter cake is then concentrated and granulated to obtain calcium ammonium nitrate product, and the filtrate is used to produce nitrophosphate fertilizer. However, this method is not suitable for medium and low-grade phosphate rock. Even for high-quality phosphate rock, the precipitation rate of calcium nitrate in the acid hydrolyzed solution after acid hydrolysis is about 80%, resulting in the calcium nitrate content in the subsequent solution and the water insolubility in the compound fertilizer. If the content exceeds the standard, it is difficult to produce high-quality fertilizers.

As a high-concentration nitrogen-phosphorus compound fertilizer, monoammonium phosphate has a significant effect on increasing agricultural production, and is the most important compound fertilizer variety recognized internationally. The traditional "phosphoric acid concentration method" and "slurry method" ammonium phosphate production process has become mature, but the impurities in the wet-process phosphoric acid are not purified during the production process, so the produced ammonium phosphate has a low purity, which can only reach Fertilizer grade. There are two main production methods for industrial phosphoric acid: one is obtained by using thermal phosphoric acid as a raw material to neutralize and react with ammonia and then crystallized; Then crystallization is obtained. The thermal phosphoric acid process has high energy consumption, and the wet phosphoric acid requires high purification technology and complex process. Before preparing industrial ammonium phosphate with traditional sulfuric acid wet-process phosphoric acid, it is necessary to remove a large amount of impurities contained in the solution by organic solvent extraction, ion exchange, chemical precipitation and other methods, including: SO ₄ ^2- , F ^- , Fe ³⁺ , Al ^{3 +} , Mg ²⁺ , etc., not only the process is cumbersome, and the phosphorus yield is not high. In addition, the water-soluble monoammonium phosphate industry has developed rapidly in recent years, and the product purity is slightly worse than that of industrial monoammonium phosphate, but better than fertilizer grade monoammonium phosphate. In October 2016, the standard for water-soluble monoammonium phosphate (HG/T 5048- 2016).

CN 101838158 A discloses a method for producing green, high-quality and high-efficiency compound fertilizer ammonium phosphate by using phosphoric acid of industrial phosphoric acid quality, mainly by relying on burning coke and coal to provide heat and producing blast furnace phosphoric acid, which has low impurity content and can be directly reacted with liquid ammonia to prepare ammonium phosphate Methods. Although this method uses coke and coal instead of electricity to provide heat, the process energy consumption is still high. The vast majority of enterprises in my country use the wet phosphoric acid process, which is not suitable for the basic production layout of Chinese enterprises. CN 102134063 A discloses a method for producing industrial phosphoric acid, industrial ammonium phosphate and phosphoric acid by one-step extraction of medium and low grade phosphate rock with hydrochloric acid method. The main technological process is that the acid hydrolyzate obtained by decomposing phosphate rock with hydrochloric acid is beaten with phosphoric acid, dissolved with hydrochloric acid, extracted with tributyl phosphate, then concentrated and decolorized to obtain industrial phosphoric acid, and the industrial phosphoric acid is added with ammonia to obtain industrial ammonium phosphate, and the concentrated industrial phosphoric acid is recycled. Food-grade phosphoric acid is obtained after removing arsenic and heavy metals. Although this method can obtain relatively pure industrial phosphoric acid, this method has a long process flow, and the usage and washing of the extractant increase the production cost, and the phosphorus loss gradually increases during the purification process, resulting in a decrease in the phosphorus yield. CN103130205 A discloses a method for producing industrial grade monoammonium phosphate and co-producing water-soluble ammonium thiophosphate. The main technological process is to use agricultural ammonium phosphate as the raw material, after adding water to dissolve, adding ammonium bicarbonate or ammonia to adjust the pH of the solution, the filtrate after filtration and separation is concentrated, crystallized, filtered and dried to obtain a monoammonium phosphate product, and the filtrate is concentrated, After drying, ammonium thiophosphate is obtained. The agricultural ammonium phosphate raw material in the method is prepared by using the sulfuric acid method wet-process phosphoric acid, which has high requirements on the grade of phosphate rock, and part of the phosphorus in the raw material enters the ammonium phosphate phosphate, resulting in a low yield of phosphorus in the industrial ammonium phosphate. . CN 104045071 A discloses an efficient impurity removal production method for extracting industrial monoammonium phosphate from ammonium phosphate production. The main technological process is that phosphoric acid and ammonia are neutralized three times, and the clear liquid obtained by filtering after the second neutralization is taken and then neutralized to obtain industrial monoammonium phosphate, and the rest is used for the production of fertilizer ammonium phosphate. Although this process can reduce the impurity content to prepare industrial monoammonium phosphate through multiple neutralization, the phosphorus in industrial monoammonium phosphate accounts for a very low proportion of phosphorus in the raw material, and most of them are converted into fertilizer ammonium phosphate with high impurity content. CN 105197905 A discloses a production method for extracting phosphate rock and co-producing feed grade calcium dihydrogen phosphate and industrial grade ammonium phosphate. The main technological process is phosphoric acid hydrolysis and flotation of phosphate concentrate. After the acid hydrolysis solution is filtered to remove the extraction residue, the filtrate is concentrated, cooled and crystallized to obtain calcium dihydrogen phosphate, and the filtrate is used to prepare ammonium dihydrogen phosphate. In this method, the yield of phosphorus in ammonium phosphate is low, and most of it is converted into calcium dihydrogen phosphate.

Patent CN109593003A discloses a production method for increasing the content of water-soluble phosphorus in citric acid-soluble phosphate fertilizer, that is, using urea sulfate to convert the citric acid-soluble phosphorus in the citric acid-soluble phosphate fertilizer into water-soluble phosphorus through the steps of mixing, curing, and curing, thereby increasing the content of water-soluble phosphorus. The process flow is long, the operation is complicated, the time required is long, and the production cost is high. Patent CN106219505A discloses a method for converting citrate-soluble phosphorus into water-soluble phosphorus, that is, using strong acid to dissolve citrate-soluble phosphorus and then adding activator, stabilizer, etc. to obtain stable water-soluble phosphorus slurry. This process needs to use strong acids such as sulfuric acid and nitric acid, and the obtained water-soluble phosphorus slurry is strongly acidic, which is not conducive to agricultural application. Patent CN201310396218.9 discloses a method for producing fully water-soluble monoammonium phosphate by using wet-process phosphoric acid, which is to separate the slurry after wet-process phosphoric acid amination reaction from solid-liquid, and concentrate and dry the filtrate to obtain fully water-soluble monoammonium phosphate. This method has a long technological process, white fertilizer is produced in the production process, and the phosphorus yield is low. Patent CN201410245006.5 discloses a method for using wet-process phosphoric acid to produce fully water-soluble monoammonium phosphate and co-production of magnesium ammonium phosphate, that is, wet-process phosphoric acid is prepared through the steps of tertiary ammoniation reaction, aging, solid-liquid separation, concentration, and crystallization. Total water-soluble monoammonium phosphate and magnesium ammonium phosphate products are obtained. The monoammonium phosphate product of this method has a high water-soluble phosphorus content, but the process is complicated, white fertilizer and magnesium ammonium phosphate are by-products, and the phosphorus yield is low.

my country's phosphate compound fertilizer industry is mainly dominated by sulfuric acid wet-process phosphoric acid, but my country's external dependence on sulfur is relatively high. The rate is not high, the added value of comprehensive utilization is not high, and a large amount of phosphogypsum is still stored, causing environmental pollution. Phosphogypsum has become one of the constraints affecting the development of my country's phosphorus compound fertilizer industry. In addition to the topic of phosphogypsum solid waste, the environmental pressure brought about by the industry's "three wastes" pollution is the main problem faced by the ammonium phosphate industry. Therefore, upgrading and transformation of process technology, upgrading of technical equipment, energy saving and consumption reduction, and improvement of phosphorus yield are inevitable trends in the development of the industry. Accordingly, we propose a production method for preparing water-soluble monoammonium phosphate by decomposing medium and low-grade phosphate rock with nitric acid. External dependence.

SUMMARY OF THE INVENTION

In view of the above problems, the technical problem solved by the present invention is to provide a preparation method of water-soluble monoammonium phosphate, which has simple process for preparing water-soluble monoammonium phosphate, high phosphorus yield and low sulfuric acid consumption.

A production method of water-soluble monoammonium phosphate, comprising the following steps:

a. Mix nitric acid and phosphate rock, react at 30 to 70 °C for 0.5 to 2 hours, and then separate the solid and liquid to obtain an acid hydrolyzate;

b. Neutralize the acid hydrolyzate to a pH of 6.5 to 8, and separate solid-liquid to obtain solid phase I and liquid phase I;

c. Mix solid phase I and sulfuric acid solution, react at 30-70°C for 0.3-2 h, and separate solid-liquid to obtain solid-phase II and liquid-phase II; neutralize liquid-phase II to pH 4.0-4.5, and then separate solid-liquid , to obtain solid phase III and liquid phase III; wherein, the liquid phase III is water-soluble monoammonium phosphate.

In one embodiment, in step c, the liquid phase II is neutralized to a pH of 4.1-4.5.

In one embodiment, in step a, the phosphate rock is in the form of powder or slurry, and the nitric acid concentration is 30-70wt% based on the water content in the phosphate rock being 0-40wt%.

In one embodiment, in step a, the amount of nitric acid is 0.9 to 1.2 times the theoretical acid consumption for the complete reaction of the phosphate rock; preferably, the amount of nitric acid is 0.9 to 1.1 times the theoretical acid consumption for the complete reaction of the phosphate rock.

In one embodiment, in step a, the solid-liquid separation is performed in two steps, firstly performing sedimentation separation, and then filtering and separating the liquid after sedimentation separation.

In one embodiment, in step b, an alkaline neutralizing agent is used for the neutralization; preferably, the alkaline neutralizing agent is in gas ammonia, ammonia water, limestone, lime milk, ammonium carbonate and ammonium bicarbonate At least one; further preferably, the alkaline neutralizer is calcium carbonate, ammonia and lime milk.

In one embodiment, in step c, the concentration of the sulfuric acid solution is 30wt% to 60wt%; the consumption of the sulfuric acid solution is 0.9 to 1.2 times the theoretical acid consumption of the solid phase I complete reaction; Phase I complete reaction is 0.95～1.05 times of the theoretical acid consumption.

In one embodiment, in step c, the neutralizing agent used for neutralizing the liquid phase II is ammonia gas or liquid ammonia.

In one embodiment, in step c, liquid phase III is processed to prepare solid water-soluble monoammonium phosphate.

Wherein, the preparation method of the solid water-soluble monoammonium phosphate is as follows: evaporating, concentrating and drying the liquid phase III to obtain the solid water-soluble monoammonium phosphate.

In one embodiment, liquid phase I is added to a substance containing nutrient elements to adjust product nutrients to obtain calcium nitrate fertilizer or calcium ammonium nitrate fertilizer; preferably, the substance containing nutrient elements is in ammonia, ammonium nitrate and calcium nitrate at least one of.

Beneficial effects of the present invention:

1. The present invention can directly utilize medium and low grade phosphate rock, and does not need to carry out phosphate rock flotation;

2. The method of the present invention completely separates phosphorus and calcium in the phosphate rock, greatly improves the utilization rate of elements such as calcium and phosphorus, and has good economic benefits;

3. The present invention can directly produce water-soluble monoammonium phosphate; obtain calcium sulfate dihydrate with high purity;

4. The amount of by-product slag in the process of producing water-soluble monoammonium phosphate in the present invention is greatly reduced;

5. This process has low comprehensive cost, basically no solid waste, realizes clean processing and utilization of phosphate rock, and has good economic and social benefits as well as broad industrial application prospects;

6. Compared with traditional sulfuric acid method and nitric acid-sulfuric acid method, the amount of sulfuric acid used in the present invention is greatly reduced;

7. The present invention does not involve the freezing step, and the process energy consumption is low.

Description of drawings

Fig. 1 is the process flow diagram of the present invention.

Detailed ways

A production method of water-soluble monoammonium phosphate, comprising the following steps:

a. Mix nitric acid and phosphate rock, react at 30～70℃ for 0.5～2h, and then separate the solid and liquid, the obtained liquid phase is the acid hydrolyzate, and the obtained solid phase is the acid insoluble matter;

b. Neutralize the acid hydrolyzate to a pH of 6.5 to 8, and separate solid-liquid to obtain solid phase I and liquid phase I;

c. Mix solid phase I and sulfuric acid solution, react at 30-70°C for 0.3-2 h, and separate solid-liquid to obtain solid-phase II and liquid-phase II; neutralize liquid-phase II to pH 4.0-4.5, and then separate solid-liquid , to obtain solid phase III and liquid phase III; wherein, the liquid phase III is water-soluble monoammonium phosphate.

Wherein, in step a, the main reaction that takes place is:

Ca ₅ F(PO ₄ ) ₃ +10HNO ₃ =5Ca(NO ₃ ) ₂ +3H ₃ PO ₄ +HF↑.

In the step a of the present invention, using nitric acid to decompose the phosphate rock to obtain low P ₂ O ₅ concentration in the acid hydrolyzate, low decomposition rate of the low activity ores containing iron and aluminum in the phosphate rock, low dissolution rate of insoluble impurities, and a considerable part exists in acid-insoluble impurities The system was separated by filtration. Compared with the sulfuric acid method, there are fewer impurity ions such as Fe and Al in the solution, and the MER value of the solution is small.

低MER值的溶液在后续处理酸解液时，可以进一步防止磷与杂质离子络合沉淀，从而提高磷的收率。Among them, the

The solution with low MER value can further prevent the complex precipitation of phosphorus and impurity ions in the subsequent treatment of acid hydrolyzate, thereby improving the yield of phosphorus.

In step b, neutralization is performed to 6.5≤pH≤8.0, the purpose of which is to precipitate all phosphorus in the acid hydrolysis solution. After solid-liquid separation, the solid phase I is mainly CaHPO ₄ , Ca ₃ (PO ₄ ) ₂ and CaF ₂ , and a small amount of Fe ³⁺ , Al ³⁺ , Mg ²⁺ metal phosphates; the liquid phase I is mainly NO ₃ ^- , Ca ²⁺ , and a small amount of H ₂ PO ₄ ^- , HPO ₄ ^2- .

In step c, the reaction that takes place is mainly:

CaHPO ₄ +H ₂ SO ₄ +2H ₂ O=CaSO ₄ ·2H ₂ O↓+H ₃ PO ₄

In step c, the solid phase I is subjected to secondary acidolysis with sulfuric acid solution, all Ca ²⁺ is precipitated as calcium sulfate dihydrate, and phosphate ions are released from calcium phosphate salts and exist in the solution. Among them, the calcium sulfate dihydrate obtained by the present invention is of high purity, and α-hemihydrate gypsum with good performance can be obtained through transformation.

The purpose of neutralizing liquid phase II to 4.0≤pH≤4.5 is to precipitate a small amount of Fe ³⁺ and Al ³⁺ impurities dissolved in the solution, so that the content of impurity ions in the solution is less, and the purpose of purifying the phosphoric acid solution is achieved. Among them, solid phase III is white fertilizer, and its components are metal phosphates, mainly iron phosphate and aluminum phosphate.

4H 2 O。 The traditional method for the separation of calcium and phosphorus in the nitric acid wet-process phosphoric acid system is as follows: firstly, acid hydrolyze the low-grade phosphate rock, and the obtained acid hydrolyzate is directly subjected to freezing crystallization to precipitate CaNO _3. 4H ₂ O. Using the method of the present invention, compared with the traditional method, the separation rate of calcium and phosphorus is greatly increased. The reason is: the neutralization method is used to allow the phosphorus to be completely precipitated from the solution and to be separated from the excess calcium ions. The calcium phosphate salt is precipitated by acid hydrolysis with sulfuric acid, and the calcium ion is combined with the sulfate radical to form a calcium sulfate precipitation, and the phosphate radical is completely released from the calcium phosphate salt. Therefore, phosphorus and calcium are completely separated through a two-step operation, and the filtrate is used to produce water-soluble monoammonium phosphate or other phosphorus-containing fertilizers.

In a specific embodiment, in order to improve the precipitation rate of impurity ions, in step c, the liquid phase II is neutralized to a pH of 4.1-4.5.

In a specific embodiment, in step a, the phosphate rock is in the form of powder or slurry. When the water content in the phosphate rock is 0%, it is in the form of powder, and as the water content increases, the phosphate rock will be in the form of powder. It becomes a slurry, for example, when the water content of the phosphate rock is 40%, it is a slurry. In the method of the present invention, the concentration of the nitric acid solution needs to be strictly controlled. The concentration of the nitric acid solution is 30-70wt% based on the water content in the phosphate rock of 0-40wt%, that is to say, when the water content in the raw phosphate rock is 0-40wt%, the concentration of the nitric acid solution is controlled to be 30-70wt% , if the water content in the raw phosphate rock exceeds 40wt%, the concentration of the nitric acid solution needs to be calculated according to the water content in the phosphate rock.

In one embodiment, in step a, the amount of nitric acid is 0.9 to 1.2 times the theoretical acid consumption for the complete reaction of the phosphate rock; preferably, the amount of nitric acid is 0.9 to 1.1 times the theoretical acid consumption for the complete reaction of the phosphate rock.

The theoretical acid consumption for the complete reaction of phosphate rock can be calculated according to the content of each component in the phosphate rock. For example, it is detected that the main components reacting with acid in a phosphate rock are calcium oxide, magnesium oxide, iron oxide and aluminum oxide. According to the content of the above components, the calcium oxide, magnesium oxide, iron oxide, The theoretical acid consumption of the complete reaction of alumina, that is, the theoretical acid consumption of the complete reaction of phosphate rock.

Wherein, the solid-liquid separation in step a can be carried out by conventional methods.

In a specific embodiment, a plate-and-frame filter can be used for solid-liquid separation.

In another specific embodiment, in step a, the solid-liquid separation is performed in two steps, firstly performing sedimentation separation, and then filtering and separating the liquid after sedimentation separation.

In one embodiment, in step b, an alkaline neutralizing agent is used for the neutralization; preferably, the alkaline neutralizing agent is in gas ammonia, ammonia water, limestone, lime milk, ammonium carbonate and ammonium bicarbonate At least one; further preferably, the alkaline neutralizer is calcium carbonate, ammonia and lime milk.

In one embodiment, in step c, the concentration of the sulfuric acid solution is 30wt% to 60wt%; the consumption of the sulfuric acid solution is 0.9 to 1.2 times the theoretical acid consumption of the solid phase I complete reaction; Phase I complete reaction is 0.95～1.05 times of the theoretical acid consumption.

Wherein, the theoretical acid consumption described in step c can be based on the ^Ca content in the solid phase I, and then according to the mol ratio of H ₂ SO ₄ and Ca ²⁺ to be 1: ₁ , calculate the consumption of H ₂ SO , namely Theoretical acid consumption.

In an embodiment, in step c, the neutralizing agent used for neutralizing the liquid phase II is ammonia gas or liquid ammonia.

In order to facilitate storage, transportation and use, in a specific embodiment, in step c, liquid phase III is processed into solid water-soluble monoammonium phosphate.

Wherein, the preparation method of the solid water-soluble monoammonium phosphate is as follows: the liquid phase III is subjected to the steps of evaporation, concentration and drying to obtain the solid water-soluble monoammonium phosphate.

The main reaction of producing water-soluble monoammonium phosphate is as follows:

H ₃ PO ₄ +NH ₃ =NH ₄ H ₂ PO ₄ ;

In one embodiment, liquid phase I is added to a substance containing nutrient elements to adjust product nutrients to obtain calcium nitrate fertilizer or calcium ammonium nitrate fertilizer; preferably, the substance containing nutrient elements is in ammonia, ammonium nitrate and calcium nitrate at least one of.

The main reactions in the production of calcium ammonium nitrate are as follows:

H ⁺ +NO ₃ ⁻ +NH ₃ +Ca ²⁺ → 5Ca(NO ₃ ) ₂ ·NH ₄ NO ₃ ·10H ₂ O.

Phosphate rock commonly used in the art is suitable for the present invention. In a specific embodiment, the P ₂ O ₅ content in the phosphate rock is 15-30 wt %; preferably, the F content in the phosphate rock is 1.5-3.0 wt %.

The specific embodiments of the present invention will be further described below with reference to the examples, but the present invention is not limited to the scope of the described examples.

The specific components of the phosphate rock used in the following examples are shown in Table 1.

Full analysis of phosphate rock used in each example of Table 1

Example 1

In this example, the content of phosphate rock P ₂ O ₅ , CaO, MgO, Fe ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and F was 27.96%, 41.30%, 1.48%, 1.94%, 1.03%, 9.93%, 2.99%, made into phosphate rock powder. The specific process is as follows:

(1) Primary acid hydrolysis: Mix phosphate rock slurry with a water content of 30% and nitric acid solution, and react at 50°C for 1.5 hours to obtain a solid-liquid mixture. After solid-liquid separation, acid-insoluble matter and liquid phase are obtained; The powder is 100g, and the 45wt% nitric acid solution is 224g; the mass of the acidolysis solution is _343g , the _P2O5 content of the acidolysis solution is 7.9%, and the CaO content is 11.7%;

(2) neutralization: the liquid phase obtained in step (1) is neutralized to solution pH=6.5 with ammonia; then solid-liquid separation is carried out to obtain liquid phase I and 65g solid phase I;

(3) nutrient regulation: liquid phase I is mixed with an appropriate amount of additives, and after concentrating and drying, calcium nitrate (ammonium) fertilizer is obtained;

(4) Secondary acid hydrolysis: Mix solid phase I with 82.5 g of sulfuric acid solution with a concentration of 45 wt%, and react at 50° C. for 0.5 h to obtain a mixed solution;

(5) solid-liquid separation: the mixed solution obtained in step (4) is subjected to solid-liquid separation to obtain solid phase II and solution II, and solid phase II is washed and filtered with hot water to obtain calcium sulfate dihydrate, and the washing water is used to prepare sulfuric acid solution;

(6) neutralization and impurity removal: liquid phase II is neutralized to solution pH=4.5 with ammonia gas, and solid-liquid separation obtains liquid phase III and solid phase III;

(7) Concentration and drying: The liquid phase III was evaporated, concentrated and dried to obtain 39.1 g of water-soluble monoammonium phosphate. Among them, it contains 60.8% of P ₂ O ₅ and 11.8% of N. The indicators of the product are HG/T 5048-2016 "Water-soluble Monoammonium Phosphate", and meet HG/T4133-2010 "Industrial Ammonium Dihydrogen Phosphate".

Example 2

In this example, the content of phosphate rock P ₂ O ₅ , CaO, MgO, Fe ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and F is 18.12%, 29.46%, 2.74%, 1.63%, 3.73%, 34.53%, 1.62%, made into phosphate rock powder. The specific process is as follows:

(1) Primary acid hydrolysis: Mix phosphate rock slurry with a water content of 20% and nitric acid solution, react at 60°C for 1 hour to obtain a solid-liquid mixture, and obtain acid-insoluble matter and liquid phase after solid-liquid separation; among them, phosphate rock powder It is 100g, 65wt% nitric acid solution is 150g; wherein the quality of the acidolysis solution is 230g, the _P2O5 content of the acidolysis solution is 7.8%, and the CaO content is 12.7% _;

(2) neutralization: the liquid phase obtained in step (1) is neutralized to solution pH=8.0 with ammonium carbonate; then solid-liquid separation is carried out to obtain liquid phase I and 43g solid phase I;

(3) nutrient regulation: liquid phase I is mixed with an appropriate amount of additives, and after concentrating and drying, calcium nitrate (ammonium) fertilizer is obtained;

(4) Secondary acid hydrolysis: Mix solid phase I with 41 g of sulfuric acid solution with a concentration of 60 wt %, and react at 60° C. for 0.5 h to obtain a mixed solution;

(5) solid-liquid separation: solid-liquid separation of the mixed liquid obtained in step (4) is performed to obtain solid phase II and solution II, and solid phase II is washed and filtered with hot water to obtain calcium sulfate dihydrate, and the washing water is used to prepare sulfuric acid solution;

(6) neutralization and impurity removal: liquid phase II is neutralized to solution pH=4.0 with ammonia gas, and solid-liquid separation obtains liquid phase III and solid phase III;

(7) Concentration and drying: The liquid phase III was evaporated, concentrated and dried to obtain 26.5 g of water-soluble monoammonium phosphate, which contained 55.0% of P ₂ O ₅ and 11.0% of N, and each product index was HG/T 5048- 2016 "Water-soluble Monoammonium Phosphate".

Example 3

In this example, the content of phosphate rock P ₂ O ₅ , CaO, MgO, Fe ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and F is 19.42%, 27.99%, 0.44%, 1.51%, 3.36%, 41.44%, 1.45%, made into phosphate rock powder. The specific process is as follows:

(1) Primary acid hydrolysis: Mix 25% water-containing phosphate rock slurry and nitric acid solution, and react at 70°C for 0.5 h to obtain a solid-liquid mixture. 100g, 161g of 50wt% nitric acid solution; wherein the mass of the acidolysis solution is 235.5g, the _P2O5 content of the acidolysis solution is ₈ %, and the CaO content is 11.5%;

(2) neutralization: the liquid phase obtained in step (1) is neutralized to solution pH=6.8 with ammonia; then solid-liquid separation is carried out to obtain liquid phase I and 44g solid phase I;

(3) nutrient regulation: liquid phase I is mixed with an appropriate amount of additives, and after concentrating and drying, calcium nitrate (ammonium) fertilizer is obtained;

(4) Secondary acid hydrolysis: Mix solid phase I with 50.5 g of sulfuric acid solution with a concentration of 50 wt%, and react at 70° C. for 0.5 h; obtain a mixed solution;

(5) solid-liquid separation: solid-liquid separation of the mixed liquid obtained in step (4) is performed to obtain solid phase II and solution II, and solid phase II is washed and filtered with hot water to obtain calcium sulfate dihydrate, and the washing water is used to prepare sulfuric acid solution;

(6) neutralization and impurity removal: liquid phase II is neutralized to solution pH=4.1 with ammonia gas, and solid-liquid separation obtains liquid phase III and solid phase III;

(7) Concentration and drying: The liquid phase III was evaporated, concentrated and dried to obtain 27.3 g of water-soluble monoammonium phosphate, which contained 56.0% of P ₂ O ₅ and 11.5% of N, and each product index was HG/T 5048- 2016 "Water-soluble Monoammonium Phosphate".

Example 4

In this example, the content of phosphate rock P ₂ O ₅ , CaO, MgO, Fe ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and F is 26.70%, 41.53%, 2.34%, 0.60%, 0.53%, 19.75%, 2.50%, made into phosphate rock powder. The specific process is as follows:

(1) Primary acid hydrolysis: Mix phosphate rock slurry with no water content and nitric acid solution, and react at 60°C for 1.2 hours to obtain a solid-liquid mixture. 100g, 330g of 30wt% nitric acid solution; wherein the mass of the acidolysis solution is 399g, the _P2O5 content of the acidolysis solution is _6.5 %, and the CaO content is 10.1%;

(2) neutralization: the liquid phase obtained in step (1) is neutralized to solution pH=7.3 with ammonium carbonate; then solid-liquid separation is carried out to obtain liquid phase I and 61.5g solid phase I;

(3) nutrient regulation: liquid phase I is mixed with an appropriate amount of additives, and after concentrating and drying, calcium nitrate (ammonium) fertilizer is obtained;

(4) Secondary acid hydrolysis: Mix solid phase I with 117 g of sulfuric acid solution with a concentration of 30 wt%, and react at 60° C. for 0.5 h to obtain a mixed solution;

(5) solid-liquid separation: the solid-liquid separation obtained in step (4) obtains solid phase II and solution II, and solid phase II is washed and filtered with hot water to obtain calcium sulfate dihydrate, and the washing water is used to prepare sulfuric acid solution;

(6) neutralization and impurity removal: liquid phase II is neutralized to solution pH=4.4 with liquid ammonia, and solid-liquid separation obtains liquid phase III and solid phase III;

(7) Concentration and drying: The liquid phase III was evaporated, concentrated, and dried to obtain 37.3 g of water-soluble monoammonium phosphate, which contained 60.9% of P ₂ O ₅ and 11.8% of N, and each product index was HG/T 5048- 2016 "Water-soluble Monoammonium Phosphate", and meet HG/T4133-2010 "Industrial Ammonium Dihydrogen Phosphate".

Example 5

In this example, the content of phosphate rock P ₂ O ₅ , CaO, MgO, Fe ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and F is 30.41%, 41.30%, 1.48%, 1.94%, 1.03%, 9.93%, 2.99%, made into phosphate rock powder. The specific process is as follows:

(1) Primary acid hydrolysis: Mix phosphate rock slurry with a water content of 40% and nitric acid solution, and react at 30°C for 2 hours to obtain a solid-liquid mixture. After solid-liquid separation, acid-insoluble matter and liquid phase are obtained; It is 100g, 310g of 40wt% nitric acid solution; wherein the mass of the acidolysis solution is _455.5g , the _P2O5 content of the acidolysis solution is 6.6%, and the CaO content is 9.5%;

(2) neutralization: the liquid phase obtained in step (1) is neutralized to solution pH=7.0 with ammonium carbonate; then solid-liquid separation is carried out to obtain liquid phase I and 72.2g solid phase I;

(3) nutrient regulation: liquid phase I is mixed with an appropriate amount of additives, and after concentrating and drying, calcium nitrate (ammonium) fertilizer is obtained;

(4) Secondary acid hydrolysis: Mix the solid phase I and 103 g of a sulfuric acid solution with a concentration of 40 wt%, and react at 30° C. for 0.5 h to obtain a mixed solution;

(5) solid-liquid separation: the solid-liquid separation obtained in step (4) obtains solid phase II and solution II, and solid phase II is washed and filtered with hot water to obtain calcium sulfate dihydrate, and the washing water is used to prepare sulfuric acid solution;

(6) neutralization and impurity removal: liquid phase II is neutralized to solution pH=4.5 with ammonia gas, and solid-liquid separation obtains liquid phase III and solid phase III;

(7) Concentration and drying: The liquid phase III was evaporated, concentrated, and dried to obtain 43.8g of ammonium phosphate, which contained 61.0% of P ₂ O ₅ and 11.8% of N, and each product index HG/T 5048-2016 "Water Soluble" Sexual Monoammonium Phosphate", and meet HG/T 4133-2010 "Industrial Ammonium Dihydrogen Phosphate".

Claims (10)

1. The production method of the water-soluble monoammonium phosphate is characterized by comprising the following steps:

a. mixing nitric acid and phosphorite, reacting for 0.5-2 h at 30-70 ℃, and performing solid-liquid separation to obtain acidolysis solution;

b. neutralizing the acidolysis solution until the pH value is 6.5-8, and performing solid-liquid separation to obtain a solid phase I and a liquid phase I;

c. mixing the solid phase I with a sulfuric acid solution, reacting for 0.3-2 h at 30-70 ℃, and carrying out solid-liquid separation to obtain a solid phase II and a liquid phase II; neutralizing the liquid phase II until the pH value is 4.0-4.5, and then carrying out solid-liquid separation to obtain a solid phase III and a liquid phase III; wherein the liquid phase III is water-soluble monoammonium phosphate.

2. The method for producing water-soluble monoammonium phosphate according to claim 1, wherein in step c, the liquid phase II is neutralized to pH 4.1-4.5.

3. The method for producing water-soluble monoammonium phosphate according to claim 1 or 2, wherein in step a, the phosphate ore is in powder or slurry form, and the concentration of nitric acid is 30-70 wt% based on the water content in the phosphate ore being 0-40 wt%.

4. The method for producing the water-soluble monoammonium phosphate according to claim 1 or 2, wherein in the step a, the amount of the nitric acid is 0.9-1.2 times of the theoretical acid consumption of complete reaction of the phosphate ore; preferably, the dosage of the nitric acid is 0.9-1.1 times of the theoretical acid consumption of the complete reaction of the phosphorite.

5. The method for producing water-soluble monoammonium phosphate according to claim 1 or 2, wherein in step a, solid-liquid separation is carried out in two steps, wherein the liquid after the solid-liquid separation is subjected to sedimentation separation and then to filtration separation.

6. The method for producing a water-soluble monoammonium phosphate according to claim 1 or 2, wherein in step b, the neutralization is performed by using a basic neutralizing agent; preferably, the alkaline neutralizing agent is at least one of gas ammonia, ammonia water, limestone, lime milk, ammonium carbonate and ammonium bicarbonate; further preferably, the alkaline neutralizing agent is calcium carbonate, ammonia and milk of lime.

7. The method for producing water-soluble monoammonium phosphate according to claim 1 or 2, wherein in step c, the concentration of the sulfuric acid solution is 30-60 wt%; the dosage of the sulfuric acid solution is 0.9-1.2 times of the theoretical acid consumption of the complete reaction of the solid phase I; preferably, the dosage of the sulfuric acid solution is 0.95 to 1.05 times of the theoretical acid consumption of the complete reaction of the solid phase I.

8. The method for producing a water-soluble monoammonium phosphate according to claim 1 or 2, wherein the neutralizing agent used for neutralizing the liquid phase II in step c is ammonia gas or liquid ammonia.

9. The method for producing water-soluble monoammonium phosphate according to claims 1-8, wherein the liquid phase III is processed into solid water-soluble monoammonium phosphate; preferably, the liquid phase III is evaporated, concentrated and dried to obtain solid water-soluble monoammonium phosphate.

10. The production method of the water-soluble monoammonium phosphate according to claim 1 or 2, characterized in that the liquid phase I is added with a substance containing nutrient elements to adjust product nutrients, and the calcium nitrate fertilizer or the calcium ammonium nitrate fertilizer is obtained through evaporation, concentration and drying; preferably, the nutrient element-containing substance is at least one of ammonia, ammonium nitrate or calcium nitrate.

Images