Wet-process phosphoric acid purification and arsenic removal system

Abstract

The utility model discloses a wet-process phosphoric acid purification and arsenic removal system, and relates to the technical field of wet-process phosphoric acid purification and impurity removal. The system comprises a phosphoric acid raw material tank, a Venturi jet reactor, a tubular washing absorber, a reaction washing curing tank and a hydrogen sulfide reactor which are sequentially connected, wherein the hydrogen sulfide reactor is also communicated with the Venturi jet reactor; the reaction washing and curing tank is communicated with an arsenic removal filtering assembly; and the arsenic removal filtering assembly is communicated with the phosphoric acid raw material tank. The problems that an existing arsenic removal system is large in sodium sulfide adding amount, hydrogen sulfide leakage is prone to occurring, the system is complex, and the arsenic index is difficult to control flexibly are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of purification and impurity removal of wet-process phosphoric acid, in particular to a wet-process phosphoric acid purification and arsenic removal system. Background Art

[0002] Solvent extraction is a common method for purifying wet-process phosphoric acid. Fertilizer-grade wet-process phosphoric acid can be purified by extraction to remove harmful impurities in phosphoric acid to obtain food-grade phosphoric acid. Food-grade phosphoric acid has extremely high requirements for the content of impurity arsenic. The current national standard (GB1886.304-2020) requires that the arsenic content in food-grade phosphoric acid be less than 0.5ppm.

[0003] The current arsenic removal system is processed in the front-end pretreatment process of the wet phosphoric acid purification device, that is, the sodium sulfide added to the phosphoric acid reacts with the arsenic in the phosphoric acid to produce a precipitate, which is then filtered out and separated, and then enters the subsequent extraction purification process, and sodium sulfide is added again to further remove arsenic.

[0004] This arsenic removal system involves the addition of sodium sulfide in the pretreatment and extraction purification steps, which produces a large amount of hydrogen sulfide. There is a safety risk of hydrogen sulfide leakage and poisoning in the area, and the difficulty of safety management and control is increased. In addition, when using this method, the arsenic removal process and process operation flow are long, and the process control and analysis results of arsenic indicators in production cannot be fed back in time, resulting in difficulty in controlling arsenic indicators and long adjustment time, resulting in food-grade phosphoric acid products not meeting standards. Utility Model Content

[0005] In order to solve the defects in the prior art, the utility model provides a wet-process phosphoric acid purification and arsenic removal system which has less sodium sulfide addition and is safer and controllable.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] The utility model provides a wet phosphoric acid purification and arsenic removal system, the system comprises a phosphoric acid raw material tank, a venturi jet reactor, a tubular washing absorber, a reaction washing and maturation tank, and a hydrogen sulfide reactor which are connected in sequence, the hydrogen sulfide reactor is also connected to the venturi jet reactor; the reaction washing and maturation tank is connected to an arsenic removal filter component, and the arsenic removal filter component is connected to the phosphoric acid raw material tank.

[0008] Furthermore, the arsenic removal filtration component includes a arsenic removal filtration delivery pump, a precision filtration circulation pump, a precision filter, and a product acid clear liquid tank connected in sequence. The precision filter is also connected to an arsenic slag concentrate tank. The outlet end of the arsenic slag concentrate tank is connected to a plate and frame filter press. The outlet end of the plate and frame filter press is connected to the phosphoric acid raw material tank.

[0009] Furthermore, the outlet end of the precision filter is also connected to the precision filtration circulation pump.

[0010] Furthermore, an arsenic slag concentrate delivery pump is connected between the arsenic slag concentrate tank and the plate and frame filter press.

[0011] Furthermore, a phosphoric acid raw material delivery pump is connected between the phosphoric acid raw material tank and the Venturi injection reactor.

[0012] Furthermore, a reaction washing circulation pump is connected between the tubular washing absorber and the reaction washing aging tank.

[0013] Furthermore, the number of the precision filters is at least one, and if there are multiple precision filters, they are connected in parallel or in series.

[0014] Furthermore, the filtration pore size of the precision filter is between 0.02 and 1.0 microns.

[0015] The beneficial effects of the utility model are:

[0016] 1. The utility model provides a wet phosphoric acid purification and arsenic removal system, which has a compact system design, reasonable layout, simple equipment structure, low operation difficulty, effectively reduces the addition of sodium sulfide, and the system is in a closed state, and the safety risk of hydrogen sulfide leakage is effectively controlled or reduced, thereby greatly improving the safety of the system; the arsenic removal reaction system and arsenic slag filtration system are added to increase the efficiency of impurity removal. It solves the problem that the existing arsenic removal system has a large amount of sodium sulfide added, which makes hydrogen sulfide leakage easy to occur, and the system is complicated and difficult to flexibly control the arsenic index. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The utility model provides a structural schematic diagram of a wet-process phosphoric acid purification and arsenic removal system.

[0018] The attached drawings are marked with: 1-phosphoric acid raw material tank, 2-Venturi jet reactor, 3-tubular washing absorber, 4-phosphoric acid raw material delivery pump, 5-reaction washing and maturation tank, 6-reaction washing circulation pump, 7-hydrogen sulfide reactor, 8-arsenic removal filtration delivery pump, 9-precision filter, 10-precision filtration circulation pump, 11-product acid clear liquid tank, 12-arsenic slag concentrated liquid tank, 13-arsenic slag concentrated liquid delivery pump, 14-plate and frame filter press. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, not all. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The utility model provides a wet phosphoric acid purification and arsenic removal system. Figure 1 The system includes a phosphoric acid raw material tank 1, a Venturi jet reactor 2, a tubular washing absorber 3, a reaction washing and maturation tank 5, and a hydrogen sulfide reactor 7 which are connected in sequence. The hydrogen sulfide reactor 7 is also connected to the Venturi jet reactor 2; the reaction washing and maturation tank 5 is also connected to an arsenic removal filter component, and the outlet of the arsenic removal filter component is connected to the phosphoric acid raw material tank 1.

[0021] In some embodiments of the present invention, please continue to refer to Figure 1 The arsenic removal filtering component includes a arsenic removal filtering delivery pump 8, a precision filtering circulation pump 10, a precision filter 9, and a product acid clear liquid tank 11 which are connected in sequence. The inlet of the arsenic removal filtering delivery pump 8 is connected to the outlet of the reaction washing and maturation tank 5, the outlet of the arsenic removal filtering delivery pump 8 is connected to the inlet of the precision filtering circulation pump 10, the outlet of the precision filtering circulation pump 10 is connected to the inlet of the precision filter 9, one outlet of the precision filter 9 is connected to the inlet of the product acid clear liquid tank 11, and the other outlet of the precision filter 9 is also connected to the inlet of the arsenic slag concentrate tank 12. The outlet end of the arsenic slag concentrate tank 12 is connected to a plate and frame filter press 14, and the outlet end of the plate and frame filter press 14 is connected to the phosphoric acid raw material tank 1.

[0022] In some embodiments of the present invention, please continue to refer to Figure 1 The other outlet end of the precision filter 9 is also connected to the inlet of the precision filtration circulation pump 10.

[0023] In some embodiments of the present invention, please continue to refer to Figure 1 An arsenic slag concentrate delivery pump 13 is connected between the arsenic slag concentrate tank 12 and the plate-frame filter press 14 . Specifically, the outlet of the arsenic slag concentrate tank 12 is connected to the inlet of the arsenic slag concentrate delivery pump 13 , and the outlet of the arsenic slag concentrate delivery pump 13 is connected to the inlet of the plate-frame filter press 14 .

[0024] In some embodiments of the present invention, please continue to refer to Figure 1 A phosphoric acid raw material delivery pump 4 is connected between the phosphoric acid raw material tank 1 and the venturi jet reactor 2. Specifically, the outlet of the phosphoric acid raw material tank 1 is connected to the inlet of the phosphoric acid raw material delivery pump 4, and the outlet of the phosphoric acid raw material delivery pump 4 is connected to the inlet of the venturi jet reactor 2.

[0025] In some embodiments of the present invention, please continue to refer to Figure 1A reaction washing circulation pump 6 is connected between the tubular washing absorber 3 and the reaction washing aging tank 5. Specifically, the outlet of the reaction washing aging tank 5 is connected to the inlet of the reaction washing circulation pump 6, and the outlet of the reaction washing circulation pump 6 is connected to the tubular washing absorber 3.

[0026] In certain embodiments of the present invention, the number of the precision filter is at least one. If there are multiple precision filters, they are connected in parallel or in series.

[0027] In certain embodiments of the present invention, the filtration pore size of the precision filter is between 0.02 and 1.0 microns.

[0028] The working process and principle of the system of the utility model are:

[0029] When the system is used, the raw acid in the phosphoric acid raw material tank 1 is transported into the venturi jet reactor 2 through the phosphoric acid raw material delivery pump 4, and the hydrogen sulfide produced by the reaction in the hydrogen sulfide reactor 7 also enters the venturi jet reactor 2. In the venturi jet reactor 2, the hydrogen sulfide reacts with the arsenic in the phosphoric acid to form arsenic sulfide, which is then circulated and sprayed for washing and fully reacting and aging through the reaction washing and aging tank 5, the reaction washing circulation pump 6, and the tubular washing absorber 3, so that the arsenic in the phosphoric acid is completely reacted to form arsenic sulfide solid precipitate. The excess unreacted hydrogen sulfide gas in the reaction washing and aging tank 5 is returned to the hydrogen sulfide reactor 7 through a pipeline.

[0030] The phosphoric acid solution containing arsenic sulfide solids in the reaction washing and maturation tank 5 is transported to the circulation pipe of the precision filter 9 by the arsenic removal filtering and delivery pump 8, and circulated at a large flow rate by the precision filtering circulating pump 10. A pressure difference is generated at the inlet and outlet ends of the filtering tube of the precision filter 9 to generate a filtering driving force. The phosphoric acid clear liquid is filtered through the filtering (membrane) tube of the precision filter 9 and enters the product acid clear liquid tank 11; the solid content of arsenic sulfide in the circulating loop of the tube of the precision filter 9 increases to form an arsenic slag concentrate, which reaches a certain solid content value and is discharged into the arsenic slag concentrate tank 12.

[0031] In actual work, continuous discharge is achieved, that is, the amount of phosphoric acid solution containing arsenic sulfide solids entering is equal to the amount of phosphoric acid clear solution and arsenic slag concentrated solution discharged, so as to achieve material inflow and outflow balance. The precision filter 9 adopts cross-flow filtration, which improves the filtration capacity, reduces the filtration attenuation rate, and solves the problem of easy clogging of the filter (membrane) tube and poor cleaning and regeneration effect.

[0032] The arsenic slag concentrate in the arsenic slag concentrate tank 12 is transported to the plate-frame filter press 14 through the arsenic slag concentrate delivery pump 13 for filtration and squeezing, and the filtered mother liquor is returned to the phosphoric acid raw material tank 1. The solid arsenic slag filtered and squeezed out is unloaded and then treated in the storage yard.

[0033] The system has a compact design, reasonable layout, simple equipment structure, and low operation difficulty. It effectively reduces the addition of sodium sulfide, and the system is fully closed. The safety risk of hydrogen sulfide leakage is effectively controlled or reduced, thereby greatly improving the safety of the system; the addition of a dearsenication reaction system and an arsenic slag filtration system makes the removal efficiency of impurities high. It solves the problem that the existing dearsenication system has a large amount of sodium sulfide added, which makes hydrogen sulfide leakage easy to occur and has low safety.

[0034] The above is a detailed description of the present invention, and the following are specific embodiments of the present invention.

[0035] Example 1

[0036] A wet phosphoric acid purification and arsenic removal system comprises a phosphoric acid raw material tank 1, a venturi jet reactor 2, a tubular washing absorber 3, a phosphoric acid raw material delivery pump 4, a reaction washing and maturation tank 5, a reaction washing circulation pump 6, a hydrogen sulfide reactor 7, a arsenic removal filtration delivery pump 8, a precision filter 9, a precision filtration circulation pump 10, a product acid clear liquid tank 11, an arsenic slag concentrate tank 12, an arsenic slag concentrate delivery pump 13, and a plate and frame filter press 14.

[0037] The inlet of the phosphoric acid raw material delivery pump 4 is connected to the acid outlet at the lower end of the phosphoric acid raw material tank 1, and the outlet of the phosphoric acid raw material delivery pump 4 is connected to the acid inlet of the Venturi injection reactor 2;

[0038] The exhaust port of the hydrogen sulfide reactor 7 is connected to the air inlet of the venturi jet reactor 2;

[0039] The venturi jet reactor 2 is connected with the tubular scrubber absorber 3, which is connected with the reaction, washing and maturation tank 5, and the insertion pipe of the tubular scrubber absorber 3 and the reaction, washing and maturation tank 5 is below the operating liquid level of the reaction, washing and maturation tank 5;

[0040] The inlet of the reaction washing circulation pump 6 is connected to the liquid outlet at the lower end of the reaction washing aging tank 5, and the outlet of the reaction washing circulation pump 6 is connected to the nozzle of the tubular washing absorber 3;

[0041] The precision filtration circulation pump 10 is connected to the pipe passage of the precision filter 9 to form a circulation loop;

[0042] The inlet of the arsenic removal filter delivery pump 8 is connected to the liquid outlet at the lower end of the reaction washing and maturation tank 5, and the outlet of the arsenic removal filter delivery pump 8 is connected to the inlet pipeline of the precision filtering circulation pump 10;

[0043] The upper liquid inlet of the arsenic slag concentrated liquid tank 12 is connected to the inlet pipeline of the precision filtering circulation pump 10;

[0044] The shell side liquid discharge port of the precision filter 9 is connected to the acid inlet of the product acid clear liquid tank 11;

[0045] The inlet of the arsenic slag concentrate delivery pump 13 is connected to the lower end outlet of the arsenic slag concentrate tank 12, the outlet of the arsenic slag concentrate delivery pump 13 is connected to the liquid inlet of the plate-frame filter press 14, and the liquid outlet of the plate-frame filter press 14 is connected to the upper end pipe port of the phosphoric acid raw material tank 1.

[0046] Among them, the precision filter 9 can be combined in parallel or in series, the filter (membrane) tube material is ceramic or non-metallic engineering material, and the filter pore size is 0.02 to 1.0 micron.

[0047] Example 2

[0048] A wet phosphoric acid purification and arsenic removal system comprises a phosphoric acid raw material tank 1, a Venturi jet reactor 2, a tubular washing absorber 3, a reaction washing and maturation tank 5, and a hydrogen sulfide reactor 7 which are connected in sequence, wherein the hydrogen sulfide reactor 7 is also connected to the Venturi jet reactor 2; the reaction washing and maturation tank 5 is connected to an arsenic removal filter component, and the outlet of the arsenic removal filter component is connected to the phosphoric acid raw material tank 1.

[0049] The arsenic removal filtration component includes a arsenic removal filtration delivery pump 8, a precision filtration circulation pump 10, a precision filter 9, and a product acid clear liquid tank 11 which are connected in sequence. The precision filter 9 is also connected to an arsenic slag concentrate tank 12. The outlet end of the arsenic slag concentrate tank 12 is connected to a plate and frame filter press 14. The outlet end of the plate and frame filter press 14 is connected to the phosphoric acid raw material tank 1.

[0050] The outlet of the reaction washing and maturation tank 5 is connected to the inlet of the arsenic removal filtering and conveying pump 8, the outlet of the arsenic removal filtering and conveying pump 8 is connected to the inlet of the precision filtering circulation pump 10, the outlet of the precision filtering circulation pump 10 is connected to the inlet of the precision filter 9, one outlet of the precision filter 9 is connected to the inlet of the product acid clear liquid tank 11, the other outlet of the precision filter 9 is also connected to the inlet of the filtering circulation pump 10, and the other outlet of the precision filter 9 is also connected to the inlet of the arsenic slag concentrate tank 12.

[0051] The outlet end of the precision filter 9 is also connected to the precision filtration circulation pump 10. An arsenic slag concentrate delivery pump 13 is connected between the arsenic slag concentrate tank 12 and the plate-frame filter press 14, the outlet of the arsenic slag concentrate tank 12 is connected to the inlet of the arsenic slag concentrate delivery pump 13, the outlet of the arsenic slag concentrate delivery pump 13 is connected to the plate-frame filter press 14, and the outlet of the plate-frame filter press 14 is connected to the phosphoric acid raw material tank 1.

[0052] A phosphoric acid raw material delivery pump 4 is connected between the phosphoric acid raw material tank 1 and the venturi jet reactor 2. A reaction washing circulation pump 6 is connected between the tubular washing absorber 3 and the reaction washing aging tank 5. Specifically, the outlet of the reaction washing aging tank 5 is connected to the inlet of the reaction washing circulation pump 6, and the outlet of the reaction washing circulation pump 6 is connected to the tubular washing absorber 3.

[0053] The outlet end of the phosphoric acid raw material tank 1 is connected to the inlet of the phosphoric acid raw material delivery pump 4, the outlet of the phosphoric acid raw material delivery pump 4 is connected to the inlet of the venturi jet reactor 2, the outlet of the venturi jet reactor 2 is connected to the inlet of the tubular washing absorber 3, the outlet of the tubular washing absorber 3 is connected to the inlet of the reaction washing and maturation tank 5, the outlet of the reaction washing and maturation tank 5 is connected to the hydrogen sulfide reactor 7, and the outlet of the hydrogen sulfide reactor 7 is connected to the venturi jet reactor 2. Another outlet of the reaction washing and maturation tank 5 is also connected to an arsenic removal filter assembly, and the outlet of the arsenic removal filter assembly is connected to the phosphoric acid raw material tank 1.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A wet phosphoric acid purification and arsenic removal system, characterized in that: The system includes a phosphoric acid raw material tank, a Venturi jet reactor, a tubular washing absorber, a reaction washing and maturation tank, and a hydrogen sulfide reactor which are connected in sequence. The hydrogen sulfide reactor is also connected to the Venturi jet reactor; the reaction washing and maturation tank is connected to an arsenic removal filter component, and the arsenic removal filter component is connected to the phosphoric acid raw material tank.

2. A wet-process phosphoric acid purification and arsenic removal system according to claim 1, characterized in that: The arsenic removal filtration component includes a arsenic removal filtration delivery pump, a precision filtration circulation pump, a precision filter, and a product acid clear liquid tank which are connected in sequence. The precision filter is also connected to an arsenic slag concentrate tank. The outlet end of the arsenic slag concentrate tank is connected to a plate and frame filter press. The outlet end of the plate and frame filter press is connected to the phosphoric acid raw material tank.

3. A wet-process phosphoric acid purification and arsenic removal system according to claim 2, characterized in that: The outlet end of the precision filter is also connected to the precision filtration circulation pump.

4. A wet-process phosphoric acid purification and arsenic removal system according to claim 3, characterized in that: An arsenic slag concentrated solution delivery pump is connected between the arsenic slag concentrated solution tank and the plate-frame filter press.

5. A wet-process phosphoric acid purification and arsenic removal system according to claim 1, characterized in that: A phosphoric acid raw material delivery pump is connected between the phosphoric acid raw material tank and the Venturi injection reactor.

6. A wet-process phosphoric acid purification and arsenic removal system according to claim 1, characterized in that: A reaction washing circulation pump is connected between the tubular washing absorber and the reaction washing aging tank.

7. A wet-process phosphoric acid purification and arsenic removal system according to claim 2, characterized in that: The number of the precision filters is at least one. If there are multiple precision filters, they are connected in parallel or in series.

8. A wet-process phosphoric acid purification and arsenic removal system according to claim 2, characterized in that: The filtration pore size of the precision filter is between 0.02 and 1.0 microns.

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