Phosphoric acid arsenic removal system

Abstract

The utility model discloses a phosphoric acid arsenic removal system which comprises a tower body, a reaction cavity is arranged in the middle of an inner cavity of the tower body, a solid-liquid separation cavity is arranged below the reaction cavity, and a tail gas alkali washing cavity is arranged above the reaction cavity; a liquid-phase communicating pipe is arranged at the bottom of the reaction cavity, the bottom end of the liquid-phase communicating pipe is connected with a filter element, the filter element is installed in the solid-liquid separation cavity in the vertical direction, a slag discharging opening is formed in the bottom of the filter element and extends out of the bottom of the tower body, and an arsenic-removed phosphoric acid outlet is formed in one side of the bottom of the solid-liquid separation cavity; the top of the reaction cavity is connected with a gas-phase communicating pipe, a spoiler with a hemispherical structure is fixedly mounted above the gas-phase communicating pipe, a gap is formed between the spoiler and the top end of the gas-phase communicating pipe, and an annular spraying pipe is mounted on the periphery of the spoiler. The phosphoric acid arsenic removal system provided by the utility model integrates the functions of arsenic removal, solid-liquid separation and tail gas alkali washing, can realize automatic arsenic removal, and is compact and reasonable in structure.

Description

TECHNICAL FIELD

[0001] The utility model relates to a phosphoric acid dearsenification system and belongs to the technical field of phosphoric acid purification. BACKGROUND

[0002] In phosphoric acid, arsenic exists in the form of arsenous acid (H3AsO3), and the presence of arsenic has a certain influence on the quality of potassium dihydrogen phosphate products, so the desulfurized phosphoric acid needs to be treated by adding a dearsenification agent.

[0003] The dearsenification agent reacts with arsenous acid in the phosphoric acid to generate arsenic sulfide (As2S3) that is insoluble in water or phosphoric acid, thereby removing arsenic in the phosphoric acid. The commonly used dearsenification agent is sodium sulfide (Na2S).

[0004] At present, phosphoric acid dearsenification generally uses a dearsenification tower, but the dearsenification tower has a single function and needs to be used in cooperation with a solid-liquid separator and a tail gas alkali washing tower. The solid-liquid separator is used to separate arsenic residue, and the tail gas alkali washing tower is used to absorb and treat tail gas, resulting in a complex and lengthy structure of the entire phosphoric acid dearsenification system.

[0005] From the above, it can be seen that the prior art has obvious inconvenience and defects in actual use, so it is necessary to improve. CONTENT OF THE UTILITY MODEL

[0006] In view of the deficiencies in the background art, the utility model provides a phosphoric acid dearsenification system which integrates dearsenification, solid-liquid separation and tail gas alkali washing functions, can realize automatic dearsenification, and has a compact and reasonable structure.

[0007] To solve the above technical problems, the utility model adopts the following technical scheme:

[0008] The phosphoric acid dearsenification system comprises a tower body, a reaction cavity is arranged in the middle of the inner cavity of the tower body, a solid-liquid separation cavity is arranged below the reaction cavity, and a tail gas alkali washing cavity is arranged above the reaction cavity.

[0009] A liquid-phase connecting pipe is arranged at the bottom of the reaction cavity, the bottom end of the liquid-phase connecting pipe is connected with a filter core, the filter core is installed in the solid-liquid separation cavity along the vertical direction, a residue discharge port is arranged at the bottom of the filter core, the residue discharge port extends out from the bottom of the tower body, and a dearsenified phosphoric acid outlet is arranged at one side of the bottom of the solid-liquid separation cavity.

[0010] A gas-phase connecting pipe is connected to the top of the reaction cavity, a semispherical resistance plate is fixedly installed above the gas-phase connecting pipe, a gap exists between the resistance plate and the top end of the gas-phase connecting pipe, and an annular spray pipe is installed around the resistance plate.

[0011] Further, an acid inlet is arranged on the side wall of the reaction cavity, and the acid inlet adopts a liquid-sealed acid inlet form.

[0012] Further, the reaction cavity is internally provided with a spray head, the spray head is connected with the sodium sulfide dissolving tank through a pipeline, and a metering pump is installed on the pipeline.

[0013] Further, a circulating pipe is connected to the outside of the reaction cavity, a phosphoric acid circulating pump is installed on the circulating pipe, and the outlet of the circulating pipe is arranged at the top of the reaction cavity and sprays materials obliquely downward.

[0014] Further, the liquid-phase connecting pipe is arranged at the upper portion of the solid-liquid separation cavity, and an electromagnetic switch valve is installed on the liquid-phase connecting pipe.

[0015] Further, the gas-phase connecting pipe is arranged at the lower portion of the tail gas alkali washing cavity.

[0016] Further, the annular spray pipe is connected with the circulating pipe outside the tail gas alkali washing cavity, and an alkali washing circulating pump is installed on the circulating pipe.

[0017] Further, the top of the tail gas alkali washing cavity is provided with a tail gas outlet, and the tail gas outlet is connected with an induced draft fan.

[0018] Compared with the prior art, the above technical scheme has the following advantages:

[0019] The utility model discloses a whole longitudinal setting, through being provided with the reaction cavity in the middle part of tower body, being provided with the solid-liquid separation cavity below the reaction cavity, being provided with the tail gas alkali washing cavity above the reaction cavity, the phosphoric acid after the heavy metal removal reaction enters the solid-liquid separation cavity and is handled automatically, and the gas-phase product generated in the heavy metal removal reaction enters the tail gas alkali washing cavity and is automatically sprayed and absorbed.

[0020] The utility model discloses a set of arsenic removal, solid-liquid separation and tail gas alkali washing function in one, can realize automatic arsenic removal, and the structure is compact and reasonable.

[0021] The utility model will be described in detail below in combination with the drawings and examples. DRAWINGS

[0022] Fig. 1 It is the structure schematic diagram of the utility model;

[0023] Fig. 2 It is the enlarged view of tower body bottom structure;

[0024] Fig. 3 It is the enlarged view of tower body top structure.

[0025] In the drawing, 1 is reaction cavity, 2 is solid-liquid separation cavity, 3 is tail gas alkali washing cavity, 4 is acid inlet, 5 is spray head, 6 is sodium sulfide dissolving tank, 7 is metering pump, 8 is phosphoric acid circulating pump, 9 is liquid-phase connecting pipe, 10 is filter core, 11 is slag outlet, 12 is arsenic removal phosphoric acid outlet, 13 is gas-phase connecting pipe, 14 is flow resistance plate, 15 is annular spray pipe, 16 is alkali washing circulating pump, 17 is tail gas outlet. DETAILED DESCRIPTION

[0026] In order to have a clearer understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described with reference to the drawings.

[0027] As Figs. 1-3 The present application provides a phosphoric acid dearsenification system, which comprises a tower body, a reaction cavity 1 is arranged in the middle of the inner cavity of the tower body, a solid-liquid separation cavity 2 is arranged below the reaction cavity 1, and a tail gas caustic washing cavity 3 is arranged above the reaction cavity 1.

[0028] An acid inlet 4 is arranged on the side wall of the reaction cavity 1, the acid inlet 4 adopts a liquid-sealed acid inlet form, and the liquid sealing depth is 20 cm (2500 Pa).

[0029] A spray head 5 is arranged in the reaction cavity 1, the spray head 5 is connected with a sodium sulfide dissolving tank 6 through a pipeline, and a metering pump 7 is arranged on the pipeline.

[0030] A circulating pipe is connected to the outside of the reaction cavity 1, a phosphoric acid circulating pump 8 is arranged on the circulating pipe, the circulating pipe is used for phosphoric acid impact circulation, the outlet of the circulating pipe is arranged on the top of the reaction cavity 1, and the material is sprayed obliquely downward.

[0031] A liquid phase communication pipe 9 is arranged at the bottom of the reaction cavity 1, the liquid phase communication pipe 9 is arranged at the upper portion of the solid-liquid separation cavity 2, an electromagnetic switch valve is arranged on the liquid phase communication pipe 9, the bottom end of the liquid phase communication pipe 9 is connected with a filter core 10, the liquid phase communication pipe 9 can guide the phosphoric acid into the filter core 10, the filter core 10 is arranged in the solid-liquid separation cavity 2 in a vertical direction, a residue discharge port 11 is arranged at the bottom of the filter core 10, the residue discharge port 11 extends out from the bottom of the tower body, and a dearsenification phosphoric acid outlet 12 is arranged at one side of the bottom of the solid-liquid separation cavity 2.

[0032] A gas phase communication pipe 13 is connected to the top of the reaction cavity 1, the gas phase communication pipe 13 is arranged at the lower portion of the tail gas caustic washing cavity 3, a hemispherical resistance plate 14 is fixedly arranged above the gas phase communication pipe 13, there is a certain height gap between the resistance plate 14 and the top end of the gas phase communication pipe 13, and the resistance plate 14 guides the tail gas generated in the dearsenification process to the surrounding.

[0033] An annular spray pipe 15 is arranged on the periphery of the resistance plate 14, the annular spray pipe 15 is connected with a circulating pipe arranged outside the tail gas caustic washing cavity 3, an alkali washing circulating pump 16 is arranged on the circulating pipe, and the annular spray pipe 15 sprays the alkali solution to absorb and process the tail gas.

[0034] A tail gas outlet 17 is arranged at the top of the tail gas caustic washing cavity 3, and the tail gas outlet 17 is connected with an induced draft fan.

[0035] The specific working principle of the present application is as follows:

[0036] The phosphoric acid enters the reaction cavity 1 from the self-feeding acid inlet 4, the spraying head 5 sprays the accurately metered sodium sulfide solution into the phosphoric acid, and the phosphoric acid is circulated by the phosphoric acid circulating pump 8, so that the sodium sulfide is fully reacted with the arsenous acid in the phosphoric acid; the phosphoric acid after the reaction is discharged into the filter core 10 through the liquid phase communication pipe 9, the disulfide arsenic in the phosphoric acid is discharged through the slag discharge port 11, and the filtered phosphoric acid is output through the dearsenicated phosphoric acid outlet 12; the gas phase product generated in the reaction process enters the tail gas alkali washing cavity 3 through the gas phase communication pipe 13, the alkali liquor is sprayed through the annular spraying pipe 15, the hydrogen sulfide gas in the gas phase product is absorbed and treated, and the absorption treatment is discharged from the tail gas outlet 17.

[0037] The above is an example of the best embodiment of the present application, wherein the parts not described in detail are the common knowledge of those skilled in the art. The protection scope of the present application is subject to the content of the claims, and any equivalent transformation based on the technical inspiration of the present application is also within the protection scope of the present application.

Claims

1. A phosphoric acid dearsenification system characterized by: The tower body is internally provided with a reaction cavity (1) in the middle, a solid-liquid separation cavity (2) below the reaction cavity (1), and a tail gas alkali washing cavity (3) above the reaction cavity (1); The bottom of the reaction cavity (1) is provided with a liquid-phase connecting pipe (9), the bottom end of the liquid-phase connecting pipe (9) is connected with a filter core (10), the filter core (10) is installed in the solid-liquid separation cavity (2) in the vertical direction, the bottom of the filter core (10) is provided with a slag discharge port (11) extending out of the bottom of the tower body, and the bottom of the solid-liquid separation cavity (2) is provided on one side with a dearsenical phosphoric acid outlet (12); The top of the reaction cavity (1) is connected with a gas-phase connecting pipe (13), the top of the gas-phase connecting pipe (13) is fixedly installed with a semi-spherical resistance plate (14), a gap is formed between the resistance plate (14) and the top end of the gas-phase connecting pipe (13), and the periphery of the resistance plate (14) is installed with an annular spraying pipe (15).

2. The phosphoric acid dearsenification system of claim 1, wherein: The sidewall of the reaction cavity (1) is provided with an acid inlet (4) in the form of liquid-sealed acid feeding.

3. The phosphoric acid dearsenification system of claim 1, wherein: The reaction cavity (1) is internally provided with a spraying head (5) connected with a sodium sulfide dissolving tank (6) through a pipeline, and a metering pump (7) is installed on the pipeline.

4. The phosphoric acid dearsenification system of claim 1, wherein: The reaction cavity (1) is externally connected with a circulating pipe, a phosphoric acid circulating pump (8) is installed on the circulating pipe, and the outlet of the circulating pipe is arranged at the top of the reaction cavity (1) to spray materials obliquely downward.

5. The phosphoric acid dearsenification system of claim 1, wherein: The liquid-phase connecting pipe (9) is arranged at the upper part of the solid-liquid separation cavity (2), and an electromagnetic switch valve is installed on the liquid-phase connecting pipe (9).

6. The phosphoric acid dearsenification system of claim 1, wherein: The gas-phase connecting pipe (13) is arranged at the lower part of the tail gas alkali washing cavity (3).

7. The phosphoric acid dearsenification system of claim 1, wherein: The annular spraying pipe (15) is connected with a circulating pipe outside the tail gas alkali washing cavity (3), and an alkali washing circulating pump (16) is installed on the circulating pipe.

8. The phosphoric acid dearsenification system of claim 1, wherein: The top of the tail gas alkali washing cavity (3) is provided with a tail gas outlet (17) connected with an induced draft fan.

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