Recycling system for waste acid in purification section

Abstract

The utility model discloses a waste acid recycling system of a purification section, and belongs to the technical field of sulfuric acid preparation. Comprising a settler, a first mud pool, a first filter press, a first filtrate tank, a second mud pool, a second filter press, a second filtrate tank, a clear acid storage tank, an arsenic removal reaction structure, a sodium hydroxide preparation tank, a fan, a spray tower, a sodium hydrosulfide preparation tank and a sodium hydrosulfide dosing tank, the arsenic removal reaction structure comprises a reaction tank, a mixer and an FBL filter; the FBL filter, a second mud pool, a second filter press, a second filtrate tank and a clear acid storage tank are connected in sequence; the FBL filter, the reaction tank, the clear acid storage tank, the second mud pool, the second filtrate tank, the sodium hydrosulfide preparation tank and the sodium hydrosulfide dosing tank are all connected with the spray tower, the spray tower is connected with the sodium hydroxide preparation tank, and the spray tower, the sodium hydrosulfide preparation tank, the sodium hydrosulfide dosing tank and the reaction tank are sequentially connected.

Description

Technical Field

[0001] This utility model belongs to the field of sulfuric acid preparation technology, and specifically relates to a waste acid recycling system in the purification process. Background Technology

[0002] A large amount of SO2 flue gas is generated during the smelting of metal sulfide ores. This SO2 flue gas is usually used to produce sulfuric acid through the smelting flue gas sulfuric acid production process. The flue gas purification process in the smelting flue gas sulfuric acid production process widely adopts wet scrubbing flue gas purification technology to purify SO2 flue gas.

[0003] For example, patent application number CN201310124705.X ​​discloses a medium- and low-grade heat energy recovery system in the production of sulfuric acid from pyrite. The system includes a waste heat boiler, a cyclone dust collector, an electrostatic precipitator, a purification economizer and a purification economizer short-circuit valve, a dynamic wave scrubbing tower, a cooling tower, a primary electrostatic precipitator, a secondary electrostatic precipitator, a drying tower, a converter, a heat exchanger, a conversion economizer and a conversion economizer short-circuit valve, a deaerator, a demineralized water tank, and a steam drum, all connected in series. The inlet and outlet of the purification economizer are connected to the outlet of the conversion economizer and the steam drum on the waste heat boiler, respectively. The outlet of the deaerator is connected to the inlet of the conversion economizer. Through the connection between the purification economizer, the conversion economizer, and the deaerator, the medium- and low-grade heat energy generated in the purification and conversion sections is simultaneously recovered and utilized.

[0004] After treating the furnace gas in a dynamic wave scrubbing tower, a large amount of acidic wastewater is generated. This acidic wastewater is usually sent back to the dynamic wave scrubbing tower for circulating spraying after the solid matter is removed. For example, patent application number CN201621341269.7 discloses a gas purification system for waste acid regeneration, which includes a dynamic wave scrubbing tower, a packed tower, an electrostatic demister, a waste acid sedimentation tank, and a dilute acid tank. The dynamic wave scrubbing tower has an air inlet, an air outlet, a water inlet, and a drain outlet. The packed tower includes a tower shell, a spray device, a pair of packing materials, a pair of packing support grids, and a liquid distributor. The tower shell has an air inlet, an air outlet, a water inlet, a drain outlet, and a sewage outlet. The pair of packing materials are installed inside the tower shell through the packing support grids. The liquid distributor is installed inside the tower shell and located between the pair of packing materials. The spray device includes a set of spray pipes, a set of nozzles, and a water inlet pipe. One end of the spray pipe is open, and the other end is open to the outside. The system is closed at one end, and has multiple nozzle mounting holes on the pipe wall. A set of nozzles are installed in the holes, and a set of spray pipes are arranged in a ring array at the top of the tower shell. The open end of the set of spray pipes is higher than the closed end. The open end of the set of spray pipes is connected to the outlet of the inlet pipe, and the inlet of the inlet pipe is connected to the inlet of the tower shell. The outlet of the dynamic wave scrubbing tower is connected to the inlet of the tower shell, and the outlet of the tower shell is connected to the inlet of the electrostatic precipitator. The outlets of the dynamic wave scrubbing tower and the tower shell are connected to the inlet of the waste acid precipitation tank, and the outlet of the electrostatic precipitator is connected to the inlet of the dilute acid tank. The waste acid precipitation tank has an overflow outlet, and the waste acid precipitation tank is connected to the inlet of the dilute acid tank through an overflow pipe.

[0005] SO2 flue gas contains a large amount of harmful impurities, such as arsenic. These impurities are deposited in the circulating washing water during the washing process, and this circulating washing water absorbs SO2 from the flue gas, forming acidic wastewater. To reduce the damage of harmful ions to the purification process, this acidic wastewater needs to be discharged from the acid production system periodically. Due to the high content of harmful impurities, this acidic wastewater cannot be recycled and reused, and direct discharge would cause environmental pollution. Therefore, it is necessary to remove the arsenic from it. Summary of the Invention

[0006] The main equation of this patent is:

[0007] 6NaHS+4HAsO2+3H2SO4→2As2S3↓+3Na2SO4+8H2O

[0008] 3Na2S+2HAsO2+3H2SO4→As2S3↓+3Na2SO4+4H2O

[0009] 2NaHS + H₂SO₄ → 2H₂S↑ + Na₂SO₄

[0010] H₂S + NaOH → NaHS + H₂O

[0011] H2S + 2NaOH → Na2S + 2H2O.

[0012] Sodium hydrosulfide is unstable under acidic conditions and produces hydrogen sulfide gas. Since this patent absorbs hydrogen sulfide gas and uses it as an arsenic removal agent, its instability in acidic conditions is not a disadvantage. Furthermore, this patent does not require high purity sodium hydrosulfide.

[0013] The solution in this patent is as follows:

[0014] This utility model embodiment provides a waste acid recycling system for a purification section. The system includes a settling tank, a first sludge tank, a first filter press 1, and a first filtrate tank 2 connected sequentially via pipelines. The inlet of the settling tank is connected to the washing liquid outlet of a dynamic wave scrubber via a pipeline, and its clear liquid outlet is connected to the water inlet of the dynamic wave scrubber via a pipeline. The system also includes an arsenic removal device and a tail gas treatment device. The arsenic removal device includes a flocculant preparation tank 10, a second sludge tank 11, a second filter press 12, a second filtrate tank 13, a clear acid storage tank 9, and at least one arsenic removal reaction structure. The first filtrate tank 2, the arsenic removal reaction structure, the clear acid storage tank 9, and the water inlet of the dynamic wave scrubber are connected sequentially via pipelines. The arsenic removal reaction structure includes a reaction tank, a mixer, and an FBL filter connected sequentially via pipelines. The flocculant preparation tank... The tank 10 is connected to the mixer via a pipeline. The filter residue outlet of the FBL filter, the second mud tank 11, the second filter press 12, the second filtrate tank 13, and the acid cleaning tank 9 are connected sequentially via pipelines. The tail gas treatment device includes a sodium hydroxide preparation tank 14, a blower 15, a spray tower 16, a sodium hydrosulfide preparation tank 17, and a sodium hydrosulfide dosing tank 18. The tail gas outlets of the FBL filter, reaction tank, acid cleaning tank 9, second mud tank 11, second filtrate tank 13, sodium hydrosulfide preparation tank 17, and sodium hydrosulfide dosing tank 18 are all connected to the air inlet of the spray tower 16 via a pipeline with the blower 15. The water inlet of the spray tower 16 is connected to the sodium hydroxide preparation tank 14 via a pipeline. The washing liquid outlet of the spray tower 16, the sodium hydrosulfide preparation tank 17, the sodium hydrosulfide dosing tank 18, and the reaction tank are connected sequentially via pipelines.

[0015] In this embodiment of the invention, there are two arsenic removal reaction structures, namely a primary arsenic removal reaction structure and a secondary arsenic removal reaction structure, which are connected in series. The primary arsenic removal reaction structure includes a primary reaction tank 3, a primary mixer 4, and a primary FBL filter 5. The secondary arsenic removal reaction structure includes a secondary reaction tank 6, a secondary mixer 7, and a secondary FBL filter 8. The primary filtrate tank 2, primary reaction tank 3, primary mixer 4, primary FBL filter 5, secondary reaction tank 6, secondary mixer 7, and secondary... The FBL filter 8 and the acid storage tank 9 are connected in sequence by pipelines. The sodium hydrosulfide dosing tank 18 is connected to the primary reaction tank 3 and the secondary reaction tank 6 by pipelines. The flocculant preparation tank 10 is connected to the primary mixer 4 and the secondary mixer 7 by pipelines. The filter residue outlets of the primary FBL filter 5 and the secondary FBL filter 8 are both connected to the second mud tank 11 by pipelines. The exhaust gas outlets of the primary reaction tank 3, the primary FBL filter 5, the secondary reaction tank 6 and the secondary FBL filter 8 are all connected to the air inlet of the spray tower 16 by pipelines with a fan 15.

[0016] Specifically, in this embodiment of the invention, the first filtrate tank 2 is lower than the first filter press 1, the second filtrate tank 13 is lower than the second filter press 12, the primary reaction tank 3 is lower than the primary mixer 4 and a first vulcanization transfer pump 19 is provided on the pipeline between the primary reaction tank 3 and the primary mixer 4, the mixer is higher than the corresponding FBL filter, the reaction tank is lower than the corresponding FBL filter, and a second vulcanization transfer pump 20 is provided on the pipeline between the secondary reaction tank 6 and the secondary mixer 7; the flocculant preparation tank 10 is connected to the primary mixer 4 and the secondary mixer 7 through a pipeline with a flocculant pump 21; the acid cleaning storage tank 9 is connected to the water inlet of the power wave scrubber through a pipeline with an acid cleaning transfer pump 22, and the second filtrate tank 13 is connected to the filter press 12 through a pipeline with a filter pump 22. The pipeline of the liquid transfer pump 23 is connected to the acid storage tank 9. The second mud tank 11 is connected to the second filter press 12 through the pipeline with the filter press pump 24. The sodium hydroxide preparation tank 14 is connected to the water inlet of the spray tower 16 through the pipeline with the liquid alkali transfer pump 25. The sodium hydrosulfide preparation tank 17 is connected to the sodium hydrosulfide dosing tank 18 through the pipeline with the sodium hydrosulfide transfer pump 26. The sodium hydrosulfide dosing tank 18 is connected to the primary reaction tank 3 and the secondary reaction tank 6 through the pipeline with the sulfurizing agent dosing pump 27. The bottom of the spray tower 16 is connected to the inlet of the circulating pump 28. The outlet of the circulating pump 28 is split into two outputs, one of which is connected to the nozzle of the spray tower 16 through a pipeline, and the other of which is connected to the sodium hydrosulfide preparation tank 17 through a pipeline.

[0017] In this embodiment of the invention, a stirrer is provided in the first mud tank, the primary reaction tank 3, the secondary reaction tank 6, the flocculant preparation tank 10, the second mud tank 11, the sodium hydroxide preparation tank 14, and the sodium hydrosulfide preparation tank 17.

[0018] Specifically, in this embodiment of the invention, the primary reaction tank 3 and the secondary reaction tank 6 both have a size of Ø2600mm×h4000mm; the primary FBL filter 5 and the secondary FBL filter 8 both have a size of Ø2600mm×h5000mm; the acid storage tank 9 has a size of Ø2600mm×h5000mm; the sodium hydroxide preparation tank 14 and the sodium hydrosulfide preparation tank 17 both have a size of Ø2000mm×h2000mm; the first mud tank and the second mud tank 11 both have a size of Ø2000mm×h2000mm; the spray tower 16 has a size of Ø2000mm×h6000mm; the flocculant preparation tank 10 has a size of Ø1300mm×h1800mm; and the fan 15 has a flow rate of 5000m³. 3 / h, the filtration area of ​​the first filter press 1 and the second filter press 12 is 20m². 2 .

[0019] The beneficial effects of the technical solution provided by this utility model embodiment are:

[0020] (1) Sodium hydrosulfide is used as an arsenic removal agent. Compared with sodium sulfide (which emits an odor when exposed to air), it is more stable and safer, and introduces fewer sodium ions.

[0021] (2) The treatment effect is good. The arsenic content of the dilute acid after treatment is reduced to below 0.3 mg / L and the solid content is less than 0.4%, which has a good purification effect on sulfur dioxide flue gas.

[0022] (3) Low cost, the processing cost of each ton of dilute acid is about 20 yuan / ton.

[0023] (4) No hydrogen sulfide is emitted, and there is basically no odor on site.

[0024] (5) The process is simple, the FBL filter can automatically discharge slag, and the labor intensity is low. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the waste acid recycling system in the purification section of this utility model embodiment.

[0026] Figure 2 This is a schematic diagram of the waste acid recycling system in the purification section of this utility model embodiment.

[0027] In the diagram: 1 First filter press, 2 First filtrate tank, 3 First-stage reaction tank, 4 First-stage mixer, 5 First-stage FBL filter, 6 Second-stage reaction tank, 7 Second-stage mixer, 8 Second-stage FBL filter, 9 Acid storage tank, 10 Flocculant preparation tank, 11 Second mud tank, 12 Second filter press, 13 Second filtrate tank, 14 Sodium hydroxide preparation tank, 15 Blower, 16 Spray tower, 17 Sodium hydrosulfide preparation tank, 18 Sodium hydrosulfide dosing tank, 19 First sulfidation transfer pump, 20 Second sulfidation transfer pump, 21 Flocculant pump, 22 Acid transfer pump, 23 Filtrate transfer pump, 24 Filter press pump, 25 Liquid alkali transfer pump, 26 Sodium hydrosulfide transfer pump, 27 Sulfidation agent dosing pump, 28 Circulation pump. Detailed Implementation

[0028] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0029] Example 1

[0030] See Figure 1 and 2 Example 1 provides a waste acid recycling system for a purification section. The system includes a pretreatment device, an arsenic removal device, and a tail gas treatment device. The pretreatment device is used to settle and filter the dilute acid to reduce its solid content. The arsenic removal device is used to remove arsenic from the dilute acid. The tail gas treatment device is used to treat the tail gas (hydrogen sulfide gas) generated during the arsenic removal process and produce an arsenic removal agent (mainly sodium sulfide, possibly containing sodium hydrosulfide).

[0031] The pretreatment device includes a settling tank (not shown), a first mud tank (not shown), a first filter press 1, and a first filtrate tank 2. The washing liquid outlet of the dynamic wave scrubber (outputting dilute acid with a high solid content), the settling tank, the first mud tank, the first filter press 1, and the first filtrate tank 2 are connected sequentially via pipelines. The clear liquid outlet of the settling tank is connected to the water inlet of the dynamic wave scrubber via a pipeline equipped with a pump to replenish water to the scrubber.

[0032] The arsenic removal device includes a flocculant preparation tank 10, a second slurry tank 11, a second filter press 12, a second filtrate tank 13, a purified acid storage tank 9, and at least one arsenic removal reaction structure. The first filtrate tank 2, the arsenic removal reaction structure (if there are multiple arsenic removal reaction structures, they are connected in series), the purified acid storage tank 9, and the water inlet of the dynamic wave scrubber are connected in sequence through pipelines to recycle the treated dilute acid. The arsenic removal reaction structure includes a reaction tank, a mixer, and an FBL filter connected in sequence through pipelines. The flocculant preparation tank 10 is connected to the mixer through pipelines to output flocculant (specifically, PAM). The filter residue outlet of the FBL filter, the second slurry tank 11, the second filter press 12, the second filtrate tank 13, and the purified acid storage tank 9 are connected in sequence through pipelines to use the dilute acid in the recycled filter residue. Specifically, there are two arsenic removal reaction structures. The first arsenic removal reaction structure removes most of the arsenic, and the amount of sodium hydrosulfide used is 0.9-1.1 times the theoretical value. The second arsenic removal reaction structure basically achieves complete arsenic removal, with sodium hydrosulfide dosage at 0.25-0.40 times the theoretical value. Flocculant dosage is 0.5-3.0 g / ton of wastewater (with low solids content).

[0033] The exhaust gas treatment device includes a sodium hydroxide preparation tank 14, a blower 15, a spray tower 16, a sodium hydrosulfide preparation tank 17, and a sodium hydrosulfide dosing tank 18. The exhaust gas outlets of the FBL filter, reaction tank, acid storage tank 9, second mud tank 11, second filtrate tank 13, sodium hydrosulfide preparation tank 17, and sodium hydrosulfide dosing tank 18 are all connected to the air inlet of the spray tower 16 via pipelines connected to the blower 15. The water inlet of the spray tower 16 is connected to the sodium hydroxide preparation tank 14 (which outputs sodium hydroxide solution) via pipelines. The washing liquid outlet of the spray tower 16, the sodium hydrosulfide preparation tank 17 (where sodium hydrosulfide is added), the sodium hydrosulfide dosing tank 18, and the reaction tank are sequentially connected via pipelines to add arsenic removal agent to the reaction tank (the total dosage is 1.20-1.33 times the theoretical value).

[0034] Example 2

[0035] See Figure 1 and 2Example 2 provides a waste acid recycling system for a purification section. This system includes a settling tank, a first sludge tank, a first filter press 1, a first filtrate tank 2, a primary reaction tank 3, a primary mixer 4, a primary FBL filter 5, a secondary reaction tank 6, a secondary mixer 7, a secondary FBL filter 8, a flocculant preparation tank 10, a second sludge tank 11, a second filter press 12, a second filtrate tank 13, a clean acid storage tank 9, a sodium hydroxide preparation tank 14, a blower 15, a spray tower 16, a sodium hydrosulfide preparation tank 17, and a sodium hydrosulfide dosing tank 18. The first filtrate tank 2 is lower than the first filter press 1, the second filtrate tank 13 is lower than the second filter press 12, the primary reaction tank 3 is lower than the primary mixer 4, the primary mixer 4 is higher than the primary FBL filter 5, the secondary mixer 7 is higher than the secondary FBL filter 8, the primary reaction tank 3 is lower than the primary FBL filter 5, and the secondary reaction tank 6 is lower than the secondary FBL filter 8. The washing liquid outlet of the dynamic wave scrubber, the settling tank, the first sludge tank, the first filter press 1, the first filtrate tank 2, the first filtrate tank 2, the first-stage reaction tank 3, the first-stage mixer 4, the first-stage FBL filter 5, the second-stage reaction tank 6, the second-stage mixer 7, the second-stage FBL filter 8, the acid cleaning storage tank 9, and the water inlet of the dynamic wave scrubber are connected sequentially via pipelines. The clear liquid outlet of the settling tank is connected to the water inlet of the dynamic wave scrubber via a pipeline with a pump. The second sludge tank 11, the second filter press 12, the second filtrate tank 13, and the acid cleaning storage tank 9 are connected sequentially via pipelines. The sodium hydrosulfide dosing tank 18 is connected to the first-stage reaction tank 3 and the second-stage reaction tank 6 via pipelines. The flocculant preparation tank 10 is connected to the first-stage mixer 4 and the second-stage mixer 7 via pipelines. The filter residue outlets of the first-stage FBL filter 5 and the second-stage FBL filter 8 are both connected to the second sludge tank 11 via pipelines. The exhaust outlets of the primary reaction tank 3, primary FBL filter 5, secondary reaction tank 6, secondary FBL filter 8, acid storage tank 9, second mud tank 11, second filtrate tank 13, sodium hydrosulfide preparation tank 17, and sodium hydrosulfide dosing tank 18 are all connected to the air inlet of the spray tower 16 through a pipeline with a fan 15.

[0036] Specifically, in this embodiment of the invention, a first sulfidation transfer pump 19 is installed on the pipeline between the primary reaction tank 3 and the primary mixer 4. A second sulfidation transfer pump 20 is installed on the pipeline between the secondary reaction tank 6 and the secondary mixer 7. The flocculant preparation tank 10 is connected to the primary mixer 4 and the secondary mixer 7 via a pipeline equipped with a flocculant pump 21. The acid storage tank 9 is connected to the water inlet of the dynamic wave scrubber via a pipeline equipped with an acid delivery pump 22. The second filtrate tank 13 is connected to the acid storage tank 9 via a pipeline equipped with a filtrate delivery pump 23. The second mud tank 11 is connected to the second filter press 12 via a pipeline equipped with a filter press pump 24. The sodium hydroxide preparation tank 14 is connected to the water inlet of the spray tower 16 via a pipeline equipped with a liquid alkali delivery pump 25. The sodium hydrosulfide preparation tank 17 is connected to the sodium hydrosulfide dosing tank 18 via a pipeline equipped with a sodium hydrosulfide delivery pump 26. The sodium hydrosulfide dosing tank 18 is connected to the primary reaction tank 3 and the secondary reaction tank 6 via a pipeline equipped with a sulfide agent dosing pump 27. The bottom of the spray tower 16 is connected to the inlet of the circulating pump 28; the outlet of the circulating pump 28 is split into two outputs, one of which is connected to the nozzle of the spray tower 16 via a pipeline (to achieve circulating spraying), and the other of which is connected to the sodium hydrosulfide preparation tank 17 via a pipeline (to output the washing solution after it reaches a certain density or pH value).

[0037] In this embodiment of the invention, the settling device is an inclined tube settling device. Agitators are provided in the first mud tank, the primary reaction tank 3, the secondary reaction tank 6, the flocculant preparation tank 10, the second mud tank 11, the sodium hydroxide preparation tank 14, and the sodium hydrosulfide preparation tank 17. The first filter press 1 and the second filter press 12 are plate and frame filter presses.

[0038] Example 3

[0039] Example 3 provides a waste acid recycling system for a purification section, which has a structure that is basically the same as that of Example 2. This example discloses some of the structural specifications and parameters, as shown in Table 1:

[0040] Table 1

[0041]

[0042] The processing cost of the method in this patent is calculated as follows:

[0043] Processing capacity: 60m 3 / d (dilute acid in the first filtrate tank), the arsenic content in the dilute acid is about 500mg / L (average).

[0044] Chemical costs: Sodium hydrosulfide at 2500 yuan / ton, sodium hydroxide at 2000 yuan / ton, flocculant at 20000 yuan / ton, water at 2 yuan / ton, electricity at 0.6 yuan / kWh, and a year of 330 days.

[0045] The arsenic content was reduced to 0.3 mg / L. The amount of sodium hydrosulfide used was 1.20-1.33 times the theoretical value (taking the maximum value). The purity of sodium hydrosulfide was assumed to be 70%. The amount of sodium hydrosulfide used was: 60*500*1.33*(56 / 75)*(3 / 2)*330*10 -6 ÷ 0.7 = 21.07 tons / year, the cost of sodium hydrosulfide is: 0.25 * 21.07 = 52,700 yuan / year. Flocculant dosage: 60 * 330 * 10 -6 =0.02 tons, the cost of flocculant is: 2 * 0.02 = 0.04 million yuan / year. The cost of sodium hydroxide is omitted in detail in this example.

[0046] Electricity cost: The power consumption is about 60KW. The car is driven for 6 hours a day. The annual electricity cost is: 60*6*330*0.6=71,200 yuan / year.

[0047] Labor costs: The process is relatively simple, estimated at 200,000 per month.

[0048] Maintenance costs: The equipment is relatively simple, estimated at 50,000 per unit.

[0049] Total cost: 145,000 (cost of reagents, raw materials, electricity, etc.) + 200,000 + 50,000 = 395,000. The processing cost of each ton of dilute acid is about 20 yuan / ton (corresponding to a sulfuric acid production of 500,000 tons / year).

[0050] Sulfide slag production: 60 * 1.0 * (246 / 56) * (1 / 3) * 330 * 10 -6 =31 tons / year (dry basis).

[0051] In this embodiment, "first" and "second" serve only as distinctions and have no other special meaning. Pumps, valves, or flow meters may be installed on the pipelines connecting the various structures as needed.

[0052] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A waste acid recycling system for a purification section, comprising a settling tank, a first sludge tank, a first filter press (1), and a first filtrate tank (2) connected sequentially by pipelines; the inlet of the settling tank is connected to the washing liquid outlet of a dynamic wave scrubber via a pipeline, and its clear liquid outlet is connected to the water inlet of the dynamic wave scrubber via a pipeline; characterized in that, The system also includes an arsenic removal unit and a tail gas treatment unit; The arsenic removal device includes a flocculant preparation tank (10), a second mud tank (11), a second filter press (12), a second filtrate tank (13), a clean acid storage tank (9), and at least one arsenic removal reaction structure. The first filtrate tank (2), the arsenic removal reaction structure, the clean acid storage tank (9), and the water inlet of the dynamic wave scrubber are connected in sequence through pipelines. The arsenic removal reaction structure includes a reaction tank, a mixer, and an FBL filter connected in sequence through pipelines. The flocculant preparation tank (10) is connected to the mixer through pipelines. The filter residue outlet of the FBL filter, the second mud tank (11), the second filter press (12), the second filtrate tank (13), and the clean acid storage tank (9) are connected in sequence through pipelines. The exhaust gas treatment device includes a sodium hydroxide preparation tank (14), a blower (15), a spray tower (16), a sodium hydrosulfide preparation tank (17), and a sodium hydrosulfide dosing tank (18). The exhaust gas outlets of the FBL filter, reaction tank, acid storage tank (9), second mud tank (11), second filtrate tank (13), sodium hydrosulfide preparation tank (17), and sodium hydrosulfide dosing tank (18) are all connected to the air inlet of the spray tower (16) through a pipeline with a blower (15). The water inlet of the spray tower (16) is connected to the sodium hydroxide preparation tank (14) through a pipeline. The washing liquid outlet of the spray tower (16), the sodium hydrosulfide preparation tank (17), the sodium hydrosulfide dosing tank (18), and the reaction tank are connected in sequence through pipelines.

2. The waste acid recycling system of the purification section according to claim 1, characterized in that, The number of the arsenic removal reaction structures is two, namely a primary arsenic removal reaction structure and a secondary arsenic removal reaction structure, which are connected in series. The primary arsenic removal reaction structure includes a primary reaction tank (3), a primary mixer (4), and a primary FBL filter (5). The secondary arsenic removal reaction structure includes a secondary reaction tank (6), a secondary mixer (7), and a secondary FBL filter (8). The first filtrate tank (2), primary reaction tank (3), primary mixer (4), primary FBL filter (5), secondary reaction tank (6), secondary mixer (7), secondary FBL filter (8), and acid storage tank (9) are connected sequentially by pipelines. The sodium hydrosulfide dosing tank (18) is connected to the primary reaction tank (3), primary mixer (4), primary FBL filter (5), secondary reaction tank (6), secondary mixer (7), secondary FBL filter (8), and acid storage tank (9). The flocculant preparation tank (10) is connected to the primary reaction tank (3) and the secondary reaction tank (6) via pipelines. The flocculant preparation tank (10) is connected to the primary mixer (4) and the secondary mixer (7) via pipelines. The filter residue outlets of the primary FBL filter (5) and the secondary FBL filter (8) are all connected to the second mud tank (11) via pipelines. The exhaust gas outlets of the primary reaction tank (3), the primary FBL filter (5), the secondary reaction tank (6) and the secondary FBL filter (8) are all connected to the air inlet of the spray tower (16) via pipelines with a fan (15).

3. The waste acid recycling system of the purification section according to claim 2, characterized in that, The first filtrate tank (2) is lower than the first filter press (1), the second filtrate tank (13) is lower than the second filter press (12), the first-stage reaction tank (3) is lower than the first-stage mixer (4), and a first vulcanization transfer pump (19) is provided on the pipeline between the first-stage reaction tank (3) and the first-stage mixer (4). The mixer is higher than the corresponding FBL filter, the reaction tank is lower than the corresponding FBL filter, and a second vulcanization transfer pump (20) is provided on the pipeline between the second-stage reaction tank (6) and the second-stage mixer (7). The flocculant preparation tank (10) is connected to the first-stage mixer (4) and the second-stage mixer (7) through a pipeline with a flocculant pump (21). The acid storage tank (9) is connected to the water inlet of the power wave scrubber through a pipeline with an acid transfer pump (22), and the second filtrate tank (13) is connected through a filtrate transfer pump (23). The pipeline is connected to the acid storage tank (9), the second mud tank (11) is connected to the second filter press (12) through the pipeline with the filter press pump (24), the sodium hydroxide preparation tank (14) is connected to the water inlet of the spray tower (16) through the pipeline with the liquid alkali transfer pump (25), the sodium hydrosulfide preparation tank (17) is connected to the sodium hydrosulfide dosing tank (18) through the pipeline with the sodium hydrosulfide transfer pump (26), the sodium hydrosulfide dosing tank (18) is connected to the primary reaction tank (3) and the secondary reaction tank (6) through the pipeline with the sulfurizing agent dosing pump (27); the bottom of the spray tower (16) is connected to the inlet of the circulating pump (28); the outlet of the circulating pump (28) is split into two outputs, one of which is connected to the nozzle of the spray tower (16) through the pipeline, and the other of which is connected to the sodium hydrosulfide preparation tank (17) through the pipeline.

4. The waste acid recycling system of the purification section according to claim 2, characterized in that, Agitators are provided in the first mud tank, the primary reaction tank (3), the secondary reaction tank (6), the flocculant preparation tank (10), the second mud tank (11), the sodium hydroxide preparation tank (14), and the sodium hydrosulfide preparation tank (17).

5. The waste acid recycling system of the purification section according to claim 2, characterized in that, The specifications of the primary reaction tank (3) and the secondary reaction tank (6) are both Ø2600mm×h4000mm, the specifications of the primary FBL filter (5) and the secondary FBL filter (8) are both Ø2600mm×h5000mm, the specifications of the acid storage tank (9) are Ø2600mm×h5000mm, the specifications of the sodium hydroxide preparation tank (14) and the sodium hydrosulfide preparation tank (17) are both Ø2000mm×h2000mm, the specifications of the first mud tank and the second mud tank (11) are both Ø2000mm×h2000mm, the specifications of the spray tower (16) are Ø2000mm×h6000mm, the specifications of the flocculant preparation tank (10) are Ø1300mm×h1800mm, and the flow rate of the blower (15) is 5000m³. 3 / h, the filtration area of ​​the first filter press (1) and the second filter press (12) is 20m². 2 .

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