Device and system for preparing ammonium phosphate and byproduct nitrophosphate fertilizer by decomposing phosphorite with nitric acid

Abstract

The utility model relates to the technical field of phosphorite treatment, in particular to a device and system for preparing ammonium phosphate and byproduct nitrophosphate fertilizer by decomposing phosphorite with nitric acid. The device comprises an acidolysis tank, the acidolysis tank is connected to a first separator, the first separator is connected to a first crystallizer, the first crystallizer is connected to a second separator, the second separator is connected to a decalcification tank, the decalcification tank is connected to a denitration tank, and the denitration tank is connected to a second crystallizer. The denitration tank is respectively connected to the repulping tank and the purification equipment; the re-pulping tank is connected to a neutralizing tank, and the neutralizing tank is connected to a first concentrator; and the purification equipment is connected to the second concentrator. According to the device disclosed by the invention, the mother liquor generated by the acidolysis tank is deeply processed to prepare monoammonium phosphate and purified phosphoric acid, meanwhile, a byproduct white fertilizer can be processed into a phosphorus (potassium) nitrate fertilizer, and a byproduct white gypsum is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of phosphate rock processing, and in particular to a device and system for preparing ammonium phosphate as a by-product of nitric acid phosphate fertilizer by decomposing phosphate rock. Background Art

[0002] Currently, the development of the phosphorus chemical industry has placed higher demands on the effective utilization of phosphorus resources and environmental protection. In the phosphorus chemical production process, monoammonium phosphate, as an important industrial raw material, is widely used in agricultural fertilizers, new energy materials (such as lithium iron phosphate), and other fields. Traditional monoammonium phosphate production methods mainly rely on the sulfuric acid method, but this method has the following technical problems:

[0003] 1. The calcium ions in the acid solution are not completely removed

[0004] During the process of nitric acid decomposition of phosphate rock, the acid solution will contain a large amount of calcium ions. If these calcium ions cannot be effectively removed, the quality and performance of subsequent phosphoric acid products will be seriously affected.

[0005] 2. Difficulty in separating acid-insoluble matter

[0006] Phosphate rock often contains a variety of impurities, including acid-insoluble mineral particles. These acid-insoluble substances are difficult to effectively separate during the production process, causing wear and tear on production equipment and affecting the purity of the final product.

[0007] 3. The viscosity of phosphoric acid is high during the denitrification process, which affects the denitrification effect

[0008] Due to the high content of impurities such as iron, aluminum, and magnesium in the raw ore, and the strong activity of nitric acid, the viscosity of phosphoric acid increases during the denitrification process, which in turn affects the denitrification efficiency and causes the nitrogen content in the final product to be relatively high.

[0009] To this end, the present application provides a device and system for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product nitric acid phosphate fertilizer. Utility Model Content

[0010] In order to overcome the shortcomings of the existing technology, the present application provides a device and system for decomposing phosphate rock with nitric acid to prepare ammonium phosphate as a by-product of nitric acid phosphate fertilizer. By deep processing the mother liquor produced in the acid hydrolysis tank, phosphate (such as monoammonium phosphate) and purified phosphoric acid are prepared, which can provide a phosphorus source for the new energy material lithium iron phosphate precursor. At the same time, the by-product white fertilizer can also be processed into nitric acid phosphate (potassium) fertilizer and the by-product white gypsum can be obtained.

[0011] The technical solution adopted by this application to solve its technical problems is:

[0012] The first object of the present application is to provide an apparatus for preparing ammonium phosphate as a by-product nitric phosphate fertilizer by decomposing phosphate rock with nitric acid, comprising an acidolysis tank connected to a first separator, the first separator connected to a first crystallizer, the first crystallizer connected to a second separator, the second separator connected to a decalcification tank, the decalcification tank connected to a denitrification tank, and the denitrification tank connected to a reslurry tank and a purification device, respectively;

[0013] The reslurry tank is connected to the neutralization tank, and the neutralization tank is connected to the first concentrator;

[0014] The purification device is connected to a second concentrator.

[0015] In some specific embodiments, the first concentrator is used to concentrate the neutralized liquid;

[0016] The second concentrator is used to concentrate the purified liquid obtained by the purification equipment.

[0017] In some embodiments, the first concentrator is connected to a granulation and drying device, the granulation and drying device is connected to a sifter, the sifter is connected to a pulverizer, and the pulverizer is connected to the granulation and drying device.

[0018] In some embodiments, the second concentrator is connected to a second crystallizer, the second crystallizer is connected to a fourth separator, and the fourth separator is connected to a dryer.

[0019] In some specific embodiments, the purification equipment includes a first-stage purifier, a second-stage purifier, and a third-stage purifier. The denitrification tank is connected to the first-stage purifier, the first-stage purifier is connected to the second-stage purifier, and the second-stage purifier is connected to the second concentrator.

[0020] In some embodiments, the second concentrator is connected to the reslurry tank, the second-stage clarifier is connected to the reslurry tank, and the third-stage clarifier is connected to the reslurry tank.

[0021] In some specific embodiments, the denitrification tank is connected to an extraction tank, the extraction tank is connected to a stripping tank, and the stripping tank is connected to a third concentrator.

[0022] In some embodiments, the three-stage purifier is connected to a ferric phosphate production line.

[0023] In some specific embodiments, the denitrification tank is connected to an acid hydrolysis tank.

[0024] The second purpose of the present application is to provide a system for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product nitric acid phosphate fertilizer, including the device described above.

[0025] The beneficial effects of this application are:

[0026] The device described in the present application prepares phosphates (such as monoammonium phosphate) and purified phosphoric acid by deep processing the mother liquor produced in the acidolysis tank, which can provide a phosphorus source for the new energy material lithium iron phosphate precursor. At the same time, the by-product white fertilizer can be processed into nitric phosphate (potassium) fertilizer and the by-product white gypsum can be obtained, thereby improving the comprehensive utilization rate of phosphate rock resources and reducing waste emissions, meeting the higher requirements of the development of the phosphorus chemical industry for the effective utilization of phosphorus resources and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present application is further described below with reference to the accompanying drawings and examples.

[0028] Figure 1 This is a schematic structural diagram of a device for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product of nitrophosphate fertilizer as described in the present application;

[0029] Figure 2 This is a schematic diagram of the structure of a portion of the device for producing nitrophosphate fertilizer after the neutralization reaction in the neutralization tank described in this application;

[0030] Figure 3 This is a schematic diagram of the structure of a portion of the purification device described in this application for producing ammonium monohydrogen phosphate;

[0031] Figure 4 This is another structural schematic diagram of the device for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product of nitric phosphate fertilizer as described in the present application;

[0032] Figure 5 This is a schematic diagram of the material flow during use of the device for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product, as described in the present application;

[0033] Among them: 101, acid hydrolysis tank; 102, first separator; 103, first crystallizer; 104, second separator; 105, neutralization tank; 106, first concentrator; 107, granulation and drying equipment; 108, crusher; 109, sifter; 201, decalcification tank; 202, third separator; 203, denitrification tank; 204, reslurry tank; 301, purification equipment; 302, second concentrator; 303, second crystallizer; 304, fourth separator; 305, dryer; 401, ferric phosphate production line; 501, extraction tank; 502, stripping tank; 503, third concentrator; 3011, first-stage purifier; 3012, second-stage purifier; 3013, third-stage purifier. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the concept, specific structure and technical effects of this application in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the formation of a better connection structure by adding or reducing connection accessories according to the specific implementation situation. The various technical features created in this application can be combined interactively without conflicting with each other.

[0035] It is currently found that water-insoluble matter accounts for 8.6% of the components of nitrophosphate fertilizer products. The higher the content of acid-insoluble matter in phosphate rock powder, the higher the acid-insoluble matter separation requirements of the nitrophosphate fertilizer equipment. If the separation efficiency is low, it will not only affect the product quality, but also shorten the service life of the equipment, increase the difficulty of operation, and affect the stable operation of the process. To produce qualified nitrophosphate fertilizer products using phosphate concentrate with an acid-insoluble matter content of 12%, the acid-insoluble matter separation rate must be greater than 30% to meet the requirements of the production process and product quality. For this purpose, the following methods are provided: Figure 1 As shown, a device for preparing ammonium phosphate as a by-product nitric phosphate fertilizer by decomposing phosphate rock with nitric acid includes an acid hydrolysis tank 101, the acid hydrolysis tank 101 is connected to a first separator 102, the first separator 102 is connected to a first crystallizer 103, the first crystallizer 103 is connected to a second separator 104, the second separator 104 is connected to a decalcification tank 201, the decalcification tank 201 is connected to a denitrification tank 203, and the denitrification tank 203 is respectively connected to a reslurry tank 204 and a purification device 301;

[0036] The reslurry tank 204 is connected to the neutralization tank 105, and the neutralization tank 105 is connected to the first concentrator 106;

[0037] The purification device 301 is connected to a second concentrator 302 .

[0038] Specifically, phosphate concentrate and nitric acid are added to an acidolysis tank to carry out an acidolysis reaction. After the reaction is completed, an acidolysis feed liquid is obtained; the acidolysis feed liquid is introduced into a first separator for separation to separate acid-insoluble matter and obtain a first filtrate; the first filtrate is introduced into a first crystallizer for crystallization to precipitate calcium nitrate crystals, and filtered to obtain a first crystallization separation liquid; the first crystallization separation liquid is then introduced into a second separator for separation to separate acid-insoluble matter again and obtain a second filtrate;

[0039] The second filtrate is introduced into a decalcification tank, sulfuric acid is added for deep decalcification to obtain a decalcified liquid; the decalcified liquid is introduced into a third separator to obtain gypsum and a third filtrate;

[0040] The third filtrate is introduced into a denitrification tank for denitrification, producing acid residue, denitrified liquid, and condensate. The acid residue is introduced into a reslurry tank. The denitrified liquid is introduced into a purification device for purification to obtain a purified liquid, which is then introduced into the second concentrated liquid for concentration. Specifically, the second concentrator 302 is used to concentrate the purified liquid obtained from the purification device 301, precipitating phosphates such as monoammonium hydrogen phosphate and diammonium dihydrogen phosphate in the purified liquid, and then filtering to obtain phosphate solids.

[0041] After the reslurry treatment in the reslurry tank, a reslurry liquid is obtained; the reslurry liquid is introduced into the neutralization tank for neutralization treatment (gaseous ammonia is added for neutralization reaction), and after the neutralization reaction is completed, a neutralized liquid is obtained; the neutralized liquid is introduced into the first concentrator for concentration treatment to obtain a concentrated feed liquid; specifically, the first concentrator 106 is used to concentrate the neutralized liquid after neutralization.

[0042] In some embodiments, the first separator includes a sedimentation tank and a filter press connected to the sedimentation tank. The filter press is used to separate the large particles of acid-insoluble matter in the acid hydrolysis liquid in the sedimentation tank, and the dense phase is separated by the filter press. The overflow liquid of the sedimentation tank is separated to remove more than 30% of the large particles of acid-insoluble matter, ensuring that the crystallization and calcium nitrate filtration operations are not affected, while also reducing wear on the equipment.

[0043] In some embodiments, the second separator includes a horizontal spiral centrifuge; the first crystallization separation liquid is heated and a filter aid is added, and then introduced into the horizontal spiral centrifuge for fine separation. The removal rate of acid-insoluble matter reaches more than 95%, which not only achieves low-cost operation of acid-insoluble matter removal, but also creates conditions for high-value utilization of white gypsum.

[0044] Specifically, during crystallization separation in the first crystallizer, since the particle size of the acid-insoluble matter is relatively small, the acid-insoluble matter in the first crystallization separation liquid cannot be filtered out using conventional centrifugal equipment. Therefore, most of the acid-insoluble matter remains in the acid-insoluble matter. The acid-insoluble matter in the first crystallization separation liquid is centrifuged in a second separator to separate most of the acid-insoluble matter and obtain a second filtrate.

[0045] like Figure 2 As shown, in some embodiments, the first concentrator 106 is connected to the granulation and drying equipment 107, the granulation and drying equipment 107 is connected to the screener 109, the screener 109 is connected to the pulverizer 108, and the pulverizer 108 is connected to the granulation and drying equipment 107.

[0046] Specifically, after the first concentrator is concentrated, a first concentrated liquid is obtained, the first concentrated liquid is introduced into a granulation and drying device for granulation and drying to obtain granulated particles, the granulated particles are introduced into a sifter for screening, the granulated particles with unqualified particle size are introduced into a grinder for crushing, the unqualified granulated particles after crushing are introduced into the granulation and drying device for granulation again, and the granulated particles with qualified particle size are cooled and packaged to obtain nitrophosphate fertilizer products.

[0047] In some embodiments, the second concentrator 302 is connected to the second crystallizer 303 , the second crystallizer 303 is connected to the fourth separator 304 , and the fourth separator 304 is connected to the dryer 305 .

[0048] Specifically, after the second concentrator performs concentration treatment, a second concentrated liquid is obtained; the second concentrated liquid is introduced into the second crystallization liquid for crystallization treatment to obtain a second crystal feed liquid; the second crystallization feed liquid is introduced into the fourth separator for separation to obtain a second crystallized product; the second crystallized product is introduced into the dryer for drying treatment, and then packaged to obtain a phosphate product.

[0049] like Figure 3 As shown, in some embodiments, the purification equipment 301 includes a first-stage purifier 3011, a second-stage purifier 3012, a third-stage purifier 3013, the denitrification tank 203 is connected to the first-stage purifier 3011, the first-stage purifier 3011 is connected to the second-stage purifier 3012, and the second-stage purifier 3012 is connected to the second concentrator 302.

[0050] Specifically, the denitrified liquid is introduced into a first-stage purifier, and a purifier is added to the first-stage purifier to remove heavy metals, sulfur and other anionic impurities in the denitrified liquid. After separation, a first-stage purified liquid is obtained; the first-stage purified liquid is introduced into a second-stage purifier, and ammonia is added to remove the cations therein: Fe 3+ 、Al 3+ Mg 2+ , Ca 2+ After separation of impurities, the second-stage purified liquid and white fertilizer are obtained; the second-stage purified liquid is introduced into the three-stage purifier to remove other accumulated cations to obtain the third-stage purified liquid and white fertilizer.

[0051] In some embodiments, the second concentrator 302 is connected to the reslurry tank 204 , the second-stage clarifier 3012 is connected to the reslurry tank 204 , and the third-stage clarifier 3013 is connected to the reslurry tank 204 .

[0052] Specifically, the separated mother liquor produced after concentration in the second concentrator is introduced into the re-slurry tank for re-slurry treatment; the second-stage purifier and the third-stage purifier produce white mud during the purification process, and the white mud is introduced into the re-slurry tank for re-slurry treatment to obtain re-slurry liquid.

[0053] In some embodiments, the denitrification tank 203 is connected to the extraction tank 501 , the extraction tank 501 is connected to the stripping tank 502 , and the stripping tank 502 is connected to the third concentrator 503 .

[0054] Specifically, the denitrified liquid can be introduced into an extraction tank for extraction treatment, and then subjected to stripping treatment in a stripping tank and concentration treatment in a third concentrator to obtain industrial phosphoric acid.

[0055] In some embodiments, the three-stage purifier 3013 is connected to the iron phosphate production line 401 .

[0056] Specifically, after purification treatment in the three-stage purifier, a three-stage purified liquid is obtained. The three-stage purified liquid contains monoammonium phosphate, which can be introduced into the production of iron phosphate to provide a phosphorus source for the production of iron phosphate.

[0057] In some embodiments, the denitrification tank 203 is connected to the acid hydrolysis tank 101 .

[0058] Specifically, denitration treatment is carried out in a denitration tank to obtain a condensate containing nitric acid. The condensate can be introduced into an acid hydrolysis tank for acid hydrolysis.

[0059] like Figure 4 and Figure 5 As shown, a device for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product of nitrophosphate fertilizer includes the following steps when in use:

[0060] Acid hydrolysis reaction: In the acid hydrolysis tank, the phosphate concentrate is mixed with nitric acid and undergoes an acid hydrolysis reaction to produce an acid hydrolysis liquid.

[0061] Initial separation: The acid hydrolysis liquid enters the first separator, where the acid-insoluble matter is separated by sedimentation and filter press to obtain the first filtrate.

[0062] Preliminary crystallization: The first filtrate enters the first crystallizer for crystallization to precipitate calcium nitrate crystals to obtain the first crystallization separated liquid.

[0063] Further separation: The first crystallization separation liquid enters the second separator, and the acid-insoluble matter is further separated by a more refined separation method (such as a horizontal spiral centrifuge) to obtain a second filtrate.

[0064] Decalcification treatment: The second filtrate enters the decalcification tank, where sulfuric acid is added for deep decalcification to obtain decalcified liquid and gypsum.

[0065] Denitration: The decalcified liquid enters the denitration tank for denitration, producing denitrated liquid, acid residue, and condensate. The condensate can be recycled and reused in the acid hydrolysis tank.

[0066] Reslurry and neutralization: The acid residue enters the reslurry tank for reslurry treatment to obtain reslurry liquid. The reslurry liquid enters the neutralization tank, where ammonia is added for neutralization reaction to obtain neutralized liquid.

[0067] Purification and Concentration: The denitrified liquid enters the purification equipment and passes through multiple purifiers to remove impurities and obtain a purified liquid. The purified liquid enters the second concentrator for concentration to precipitate phosphates (such as ammonium monohydrogen phosphate).

[0068] Subsequent processing: The neutralized liquid is concentrated in the first concentrator to obtain a concentrated liquid, which is then granulated, dried, screened, and crushed to produce the nitrophosphate fertilizer product. The phosphate from the second concentrator enters the second crystallizer for crystallization, and the phosphate product is obtained after separation and drying.

[0069] Similarly, the present application also provides a system for decomposing phosphate rock with nitric acid to prepare ammonium phosphate as a by-product nitric phosphate fertilizer. The system includes the above-mentioned device, pipes and valves connecting the various devices of the device, a controller and corresponding auxiliary equipment, such as vacuum equipment, cooling equipment for providing coolant, steam equipment for providing heat source, etc.

[0070] The above is a specific description of the preferred implementation of the present application, but the invention of the present application is not limited to the described embodiments. Technical personnel familiar with the art can also make various equivalent modifications or substitutions without violating the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A device for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product nitrophosphate fertilizer, characterized in that: The invention comprises an acidolysis tank (101), wherein the acidolysis tank (101) is connected to a first separator (102), the first separator (102) is connected to a first crystallizer (103), the first crystallizer (103) is connected to a second separator (104), the second separator (104) is connected to a decalcification tank (201), the decalcification tank (201) is connected to a denitrification tank (203), and the denitrification tank (203) is respectively connected to a reslurry tank (204) and a purification device (301); The reslurry tank (204) is connected to the neutralization tank (105), and the neutralization tank (105) is connected to the first concentrator (106); The purification device (301) is connected to a second concentrator (302).

2. The device according to claim 1, characterized in that The first concentrator (106) is used to concentrate the neutralized liquid; The second concentrator (302) is used to concentrate the purified liquid obtained by the purification equipment (301).

3. The device according to claim 1, characterized in that The first concentrator (106) is connected to the granulation drying device (107), the granulation drying device (107) is connected to the sifter (109), the sifter (109) is connected to the pulverizer (108), and the pulverizer (108) is connected to the granulation drying device (107).

4. The device according to claim 1, characterized in that The second concentrator (302) is connected to the second crystallizer (303), the second crystallizer (303) is connected to the fourth separator (304), and the fourth separator (304) is connected to the dryer (305).

5. The device according to claim 1, characterized in that The purification equipment (301) includes a first-stage purifier (3011), a second-stage purifier (3012), and a third-stage purifier (3013). The denitrification tank (203) is connected to the first-stage purifier (3011), the first-stage purifier (3011) is connected to the second-stage purifier (3012), and the second-stage purifier (3012) is connected to the second concentrator (302).

6. The device according to claim 5, characterized in that The second concentrator (302) is connected to the reslurry tank (204), the second-stage clarifier (3012) is connected to the reslurry tank (204), and the third-stage clarifier (3013) is connected to the reslurry tank (204).

7. The device according to claim 5, characterized in that The denitrification tank (203) is connected to the extraction tank (501), the extraction tank (501) is connected to the stripping tank (502), and the stripping tank (502) is connected to the third concentrator (503).

8. The device according to claim 5, characterized in that The three-stage purifier (3013) is connected to the iron phosphate production line (401).

9. The device according to claim 1, characterized in that The denitrification tank (203) is connected to the acid hydrolysis tank (101).

10. A system for decomposing phosphate rock with nitric acid to produce ammonium phosphate as a by-product of nitrophosphate fertilizer, characterized in that: The invention comprises the device according to any one of claims 1 to 9.

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