A method for treating high-arsenic acid pollution using pyrite with ultrasound-assisted superconducting strong magnetic field enhancement

Abstract

This invention provides a method for treating high-arsenic waste acid using pyrite enhanced by ultrasound and a superconducting strong magnetic field, belonging to the field of heavy metal pollution control technology. The method first involves grinding pyrite and reacting it with waste acid under ultrasonic waves to form arsenic sulfide precipitate. After solid-liquid separation, air is introduced into the separated liquid while controlling the solution pH. A superconducting strong magnetic field is then introduced to carry out the arsenic precipitation reaction with ferric arsenate. Finally, lime slurry is added to the treated water, and the final pH of the solution is controlled at 8-12, ultimately yielding deeply purified industrial wastewater and refined gypsum products. This invention, by introducing an external field to enhance the treatment of high-arsenic waste acid using pyrite, not only has advantages such as simple operation, low operating cost, short treatment cycle, low slag production, and significant arsenic removal effect, but also obtains refined gypsum products with CaSO4 purity >96%. This invention maximizes the treatment of waste acid while simultaneously utilizing its valuable components, bringing additional economic benefits to enterprises.

Description

Technical Field

[0001] This invention relates to the field of heavy metal pollution control technology, and in particular to a method for treating high-arsenic acid pollution using pyrite with ultrasonic waves and a superconducting strong magnetic field. Background Technology

[0002] Arsenic-containing wastewater mainly originates from arsenic-laden acidic wastewater collected in the aqueous solution before flue gas scrubbing and purification during non-ferrous (Cu, Pb, Zn, Ni, and Sn) smelting processes. The arsenic concentration in this wastewater can reach 0.5–30 g / L, and the sulfuric acid concentration can reach 10–200 g / L. It also contains various heavy metals such as Cu, Pb, Zn, and Sb, exhibiting complex composition, high toxicity, large discharge volumes, and significant challenges in disposal, making it a major source of pollution from non-ferrous smelting. Leakage or indiscriminate discharge of arsenic-containing wastewater will cause serious harm to the ecological environment and human safety. Arsenic can enter the human body through various pathways, such as through respiration, drinking water, and the food chain. Once inside the body, arsenic readily combines with -SH to form stable complexes. These complexes hinder cellular respiration, affect cellular metabolism, and inhibit the synthesis and function of various enzymes, leading to organ damage. Prolonged exposure to arsenic-containing environments can cause skin and liver cancers. Excessive arsenic intake can cause varying degrees of harm to the body.

[0003] Currently, the main methods for treating high-arsenic acid wastewater are the lime-iron salt method, the sulfidation method, the onion stone precipitation method, and the evaporation and concentration method. The lime-iron salt method involves first adding lime slurry to the high-arsenic acid wastewater to adjust the pH to 10-11. Calcium ions react with arsenite and arsenate ions to form calcium arsenite and calcium arsenate salt precipitates. Then, air is introduced to oxidize the residual arsenite ions in the wastewater to arsenate ions. Finally, an iron salt coagulant is added to remove the residual arsenic as a precipitate. This method has a simple process flow, strong adaptability to wastewater with different arsenic concentrations, and significant arsenic removal efficiency. However, because the wastewater contains a large amount of sulfate ions, the lime slurry first neutralizes and precipitates sulfate ions during the arsenic removal process, and then combines with arsenate and arsenite ions, resulting in the generation of a large amount of sludge. Arsenate in the sludge has poor stability and high solubility, easily released into the environment causing secondary pollution. Furthermore, direct air oxidation of arsenite ions is slow and ineffective, requiring a high dosage of iron salt coagulant. The sulfidation method involves adding a sulfiding agent to high-arsenic wastewater to generate insoluble and stable arsenic sulfide precipitate. Simultaneously, heavy metal ions in the solution react with the sulfiding agent to form sulfide precipitates with low solubility products. Finally, arsenic and heavy metal ions are removed from the solution through solid-liquid separation. The sulfidation method has advantages such as simple operation, small amount of arsenic sulfide slag, low water content, the arsenic removal process being unaffected by solution pH, and high water recovery rate. However, the cost of sulfide reagents is high, the surface of the arsenic sulfide slag easily adsorbs arsenic ions, requiring safe storage; furthermore, the solution after arsenic removal requires further neutralization, generating a large amount of neutralization slag solid waste. The onion stone precipitation method involves adding an iron source to high-arsenic wastewater under specific conditions to form highly stable onion stone precipitate. This arsenic carrier has an arsenic content as high as 23%, and its synthesis process has advantages such as low iron source consumption and small slag volume. However, the onion stone synthesis process requires specific environments, such as suitable solution pH and Fe / As molar ratio, high reaction temperature, and a long arsenic precipitation period, which severely limit the industrial application of the onion stone precipitation method. Evaporation concentration is a method to reduce the volume of high-arsenic waste acid solution by heating and evaporating it to crystallize it. This method effectively reduces the volume of waste acid solution and can recover valuable substances such as sulfuric acid and heavy metals. However, it is energy-intensive and causes severe corrosion to equipment, making it difficult to promote its widespread application. Therefore, considering the characteristics of high-arsenic waste acid from non-ferrous smelting—large output, high toxicity, and high acid content—there is an urgent need to develop a complete set of key technologies that are simple to operate, have low operating costs, produce little slag, have a significant arsenic removal effect, and can effectively recover valuable sulfate ions from the waste acid.

[0004] Chinese invention patent CN108793583B discloses a method for treating wastewater containing trivalent arsenic using a combination of microorganisms and pyrite. The method involves adding ferrous salt and pyrite to the wastewater containing trivalent arsenic, along with iron-oxidizing bacteria in their logarithmic growth phase. After adjusting the pH and reaction temperature, the mixture is placed in a shaker and reacted for 3-5 days. The precipitate is then separated after settling. This invention involves the synergistic removal of arsenic by microorganisms and pyrite, but the operation is complex and the treatment cycle is long. Furthermore, the use of ferrous salt is costly, hindering its industrial application.

[0005] Chinese invention patent CN113683150B discloses a method for removing arsenic from copper smelting wastewater using a zinc slag / pyrite composite treatment agent. The method involves mixing zinc slag and pyrite at a mass ratio of (1-3):1, ball milling to obtain the composite treatment agent, and then adding it to the arsenic-containing copper smelting wastewater and stirring for 4-6 hours to remove arsenic. This invention, using zinc slag as the main component of the composite treatment agent, introduces new heavy metal impurities into the waste acid, increasing the negative impact on downstream treatment. Furthermore, the alkaline oxides in the zinc slag increase the solution pH, which is detrimental to As₂S₃ precipitation and also wastes sulfate ions in the solution.

[0006] Chinese invention patent CN111003864B discloses a method for removing arsenic from polluted acid using ultrasound enhancement. The method involves first preheating the polluted acid to 35°C, then adding a certain amount of hot iron powder (temperature: 35–80°C) and copper sulfate solution, and finally introducing an ultrasound-enhanced reaction to remove arsenic. However, this invention requires preheating of the iron powder, which is not only energy-intensive but also carries certain operational risks. Furthermore, using purely chemical reagents such as iron powder and copper sulfate solution is costly and introduces new heavy metal impurities.

[0007] In summary, existing technologies for treating high-arsenic waste acid have problems such as complex operation, long reaction cycle, large amount of chemical reagents and slag, and high operating costs. Summary of the Invention

[0008] To address the aforementioned technical problems in existing technologies, this invention provides a method for treating high-arsenic acid pollution using pyrite with ultrasound synergistic with a superconducting strong magnetic field. This method is the first to employ ultrasound synergistically with a superconducting strong magnetic field to enhance the treatment of high-arsenic acid pollution. Combined with multi-factor experiments, it optimizes the performance of arsenic removal from pyrite using an external field and the preparation of refined gypsum products, comprehensively expanding its adaptability to various scenarios. This provides a simple, low-cost, and highly effective method for treating high-arsenic acid pollution in the non-ferrous smelting industry.

[0009] The technical solution is as follows:

[0010] A method for treating high-arsenic acid pollution using pyrite with ultrasound-assisted superconducting strong magnetic field enhancement, the method comprising:

[0011] S1. Crush and grind pyrite to obtain pyrite arsenic precipitation agent;

[0012] S2. Add arsenic precipitation agent to the waste acid and perform ultrasonic reaction while stirring until arsenic sulfide precipitate is generated. Separate the reactants into solid and liquid to obtain arsenic sulfide precipitate and separation liquid.

[0013] S3. Air is introduced into the separation liquid and the pH value of the separation liquid is controlled to be 0.5-3.5 to generate ferric arsenate and obtain a solid-liquid mixture;

[0014] S4. The solid-liquid mixture obtained in step S3 is placed in a superconducting strong magnetic field, and air is continuously introduced to carry out the oxidation reaction, so that the arsenite ions / Fe in the solid-liquid mixture... 2+ It undergoes a rapid oxidation reaction with O2 in the air, accelerating the reaction of arsenate ions with Fe. 3+ Ferric arsenate precipitate is generated. After the reaction is completed, the reactants are separated into solid and liquid components to obtain ferric arsenate precipitate and treated water.

[0015] S5. Add lime slurry to the treated water obtained in step S4, and control the final pH of the solution to 8-12 to finally obtain industrial wastewater with deep purification and refined gypsum products, thereby achieving deep purification of waste acid and effective recovery and utilization of sulfate ions; the amount of lime slurry added is determined by adjusting the pH value.

[0016] Preferably, in step S1, the pyrite has an S content ≥45% and an Fe content ≥45%; the grinding is performed to a mesh size of 400 or less.

[0017] Specifically, crushing and grinding pyrite to below 400 mesh increases the reaction surface area with the polluted acid. Pyrite, as a sulfuric acid... - / Fe 2+ Arsenic precipitation agent, under S2 conditions, causes pyrite to dissolve rapidly and release S. - and Fe 2+ Ions, of which S - The ions will react directly with the trivalent arsenic ions in the waste acid to form arsenic sulfide precipitate.

[0018] Since the treated waste acid in step S3 still contains some arsenic ions, to further remove these arsenic ions, air is introduced and the pH of the solution is controlled at 0.5–3.5 to generate ferric arsenate. In step S4, by controlling the magnetic field induction intensity, the ratio of arsenite ions to Fe in the mixed solution is promoted. 2+ It undergoes a rapid oxidation reaction with O2 in the air, accelerating the reaction of arsenate ions with Fe. 3+ Ferric arsenate precipitate is generated to remove arsenic ions from the waste acid, ultimately yielding treated water;

[0019] Preferably, the concentration of arsenic ions in the polluted acid during step S2 is greater than 0.5 g / L.

[0020] Preferably, in step S2, the addition ratio of arsenic precipitation agent to waste acid is FeS2:As molar ratio (0.5-2):1.

[0021] Preferably, in step S2, the ultrasonic power is 50-400W and the stirring speed is 160-240r / min.

[0022] Preferably, the reaction temperature in step S2 is 23–50°C and the reaction time is 0.05–0.9 h.

[0023] Preferably, the airflow rate in step S3 is 80-150 m³ / h. 3 / h.

[0024] Preferably, the magnetic induction intensity of the superconducting strong magnetic field in step S4 is (2.0~4.5)×10⁻⁶. 3 The oxidation reaction time is 0.02–0.5 h; the resulting treated water can be recycled as an acid washing medium for arsenic-containing flue gas, reducing the amount of spray water used in the flue gas acid washing process.

[0025] The arsenic ion concentration in the treated water obtained in step S4 is lower than the integrated wastewater discharge standard (GB8978-1996).

[0026] The industrial wastewater obtained in step S5 meets the comprehensive industrial wastewater discharge standard; the CaSO4 purity in the refined gypsum product obtained reaches over 96%.

[0027] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0028] (1) This invention uses ultrasonic enhancement to dissolve pyrite and release S - and Fe 2+ The ions reduce the energy barrier that the total or partial reactions involved in the arsenic precipitation process need to overcome, thereby accelerating the precipitation rate of arsenic sulfide, shortening the reaction cycle, and preventing the arsenic sulfide precipitate generated during the arsenic removal process from dissolving back.

[0029] (2) Using superconducting high-strength magnets can not only promote Fe 2+ It reacts with oxygen to produce a Fenton reaction, accelerating the reaction of arsenite ions and Fe in the polluted acid. 2+ It can increase the ion oxidation rate and the activity of arsenate ions in the solution, promote the precipitation reaction of ferric arsenate, and shorten the reaction time. At the same time, it can improve the sedimentation rate of arsenic sulfide and ferric arsenate flocs, achieving effective separation of solution and solid.

[0030] (3) This invention proposes a strategy for the recovery and utilization of sulfate ions in waste acid, avoiding the generation of arsenic-containing neutralization residue in conventional treatment processes. The refined gypsum product prepared has a CaSO4 purity of over 96%, maximizing the resource utilization of waste acid and bringing additional economic benefits to enterprises.

[0031] (4) Compared with conventional pyrite treatment of high-arsenic waste acid, the present invention introduces external field assistance, which not only reduces the amount of pyrite used, but also increases the reaction rate and shortens the waste acid treatment cycle, which is conducive to industrial promotion and utilization.

[0032] (5) Pyrite is selected as an arsenic precipitation agent to make full use of its sulfur and iron elements, resulting in a small and stable amount of slag, which has the effect of "killing two birds with one stone". In addition, pyrite is cheap and readily available, which effectively reduces operating costs. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a photograph of the refined plaster obtained in Embodiment 3 of the present invention;

[0035] Figure 2 This is a microscopic image of the refined plaster obtained in Example 3 of the present invention. Detailed Implementation

[0036] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0037] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0038] This invention provides a method for treating high-arsenic acid pollution using pyrite with ultrasound-assisted superconducting strong magnetic field enhancement.

[0039] A method for treating high-arsenic acid pollution using pyrite with ultrasound-assisted superconducting strong magnetic field enhancement, the method comprising:

[0040] S1. Crush and grind pyrite to below 400 mesh;

[0041] S2. Add the pyrite obtained in step S1 to the closed reaction tank A as an arsenic precipitation agent. Introduce the waste acid into the reaction tank A through a water pump and pipeline. Turn on the ultrasonic generator and stir to carry out the reaction and generate arsenic sulfide precipitate.

[0042] S3. The waste acid from step S2, from which arsenic sulfide precipitate was removed, is introduced into reaction tank B via a water pump and pipeline. Air is introduced and the pH of the solution is controlled to be 0.5-3.5 to generate ferric arsenate, resulting in a solid-liquid mixture.

[0043] S4. Introduce the solid-liquid mixture obtained in step S3 into a superconducting strong magnetic field. By controlling the magnetic field strength, promote the arsenite ion / Fe ratio in the mixture. 2+ It undergoes a rapid oxidation reaction with O2 in the air (generally 0.02–0.5 h), accelerating the precipitation rate of ferric arsenate, removing arsenic ions from the waste acid, and finally obtaining treated water;

[0044] S5. Introduce the treated water obtained in step S4 into reaction tank C, add lime slurry, and control the final pH of the solution to be 8-12, so as to finally obtain industrial discharge deep purified water and refined gypsum products.

[0045] The following description, in conjunction with specific embodiments, illustrates this point.

[0046] The chemical composition of pyrite used in the embodiments of the present invention is shown in Table 1.

[0047] Table 1

[0048] element Fe S Si Al O As Others Content (wt.%) 46.26 45.25 0.38 0.16 3.06 0.02 4.87

[0049] Example 1

[0050] The specific steps are as follows:

[0051] (1) Crushing and grinding pyrite to a mesh size of less than 500, accounting for 50%, is beneficial to increasing the reaction area with the polluted acid;

[0052] (2) Add an appropriate amount of pyrite to the closed reaction tank A as S. - / Fe 2+ Arsenic precipitation agent was introduced into reaction tank A via a water pump and pipeline, along with waste acid (chemical composition shown in Table 2). The reaction was carried out for 0.9 hours at an ultrasonic power of 50W, a stirring speed of 240 r / min, and a reaction temperature of 50℃. Under these conditions, pyrite rapidly dissolved, releasing sulfur. - and Fe 2+ Ions, of which S - The ions will react directly with the trivalent arsenic ions in the waste acid to form arsenic sulfide precipitate;

[0053] (3) The waste acid after step (2) still contains some arsenic ions. In order to further remove these arsenic ions, they are introduced into reaction tank B through a water pump and pipeline, and air is introduced into it while controlling the pH of the solution to 0.5 to generate ferric arsenate and obtain a solid-liquid mixture.

[0054] (4) Introduce the solid-liquid mixture obtained in step (3) into a superconducting strong magnetic field, and promote the arsenite ion / Fe ratio in the mixture by controlling the magnetic field induction intensity. 2+ It undergoes a rapid oxidation reaction with O2 in the air, with a reaction time of 0.02 h, while simultaneously accelerating the precipitation rate of ferric arsenate, thus achieving efficient removal of arsenic ions from wastewater. The final concentration of arsenic ions in the treated water is 0.40 mg / L, which is lower than the Integrated Wastewater Discharge Standard (GB8978-1996).

[0055] (5) The treated water obtained in step (4) is introduced into reaction tank C, and lime milk is added to it. The final pH of the solution is controlled to be 12, and finally industrial discharge deep purified water and refined gypsum products are obtained, realizing deep purification of waste acid and effective recovery and utilization of sulfate ions.

[0056] In step (2), the concentration of arsenic ions in the waste acid is 0.5 g / L, and the addition ratio of pyrite to waste acid is 0.5:1 (FeS2:As molar ratio).

[0057] The air flow rate in step (3) is 80m³ / h. 3 / h.

[0058] In step (4), the magnetic induction intensity is 2000mT, and the effluent can be recycled as an acid washing medium for arsenic-containing flue gas, reducing the amount of spray water used in the flue gas acid washing process.

[0059] The industrial wastewater obtained in step (5) meets the comprehensive industrial wastewater discharge standard (chemical composition is shown in Table 3) and can be reused; the CaSO4 purity in the refined gypsum product reaches 96.5%.

[0060] Table 2

[0061] element As <![CDATA[H2SO4]]> Zn Fe Sb Mg Pb Concentration (mg / L) 500 21000 15.36 18.90 6.74 0.42 7.35 element Ni Cd Hg Cl F Cr Cu Concentration (mg / L) 2.72 4.68 0.01 67.92 46.6 0.36 23.68

[0062] Table 3

[0063] element As F Zn Fe Sb Mg Pb Concentration (mg / L) 0.10 0.02 0.10 8.32 0.03 0.01 0.32 element Ni Cd Cl Concentration (mg / L) 0.65 0.21 0.64

[0064] Example 2

[0065] The specific steps are as follows:

[0066] (1) Crushing and grinding pyrite to below 400 mesh (80%) is beneficial to increasing the reaction area with the polluted acid;

[0067] (2) Add an appropriate amount of pyrite to the closed reaction tank A as S. - / Fe 2+ Arsenic precipitation agent was introduced into reaction tank A via a water pump and pipeline, along with waste acid (chemical composition shown in Table 4). The reaction was carried out for 0.6 hours at an ultrasonic power of 400W, a stirring speed of 240 r / min, and a reaction temperature of 45℃. Under these conditions, pyrite rapidly dissolved, releasing sulfur. - and Fe 2+ Ions, of which S - The ions will react directly with the trivalent arsenic ions in the waste acid to form arsenic sulfide precipitate;

[0068] (3) The waste acid after step (2) still contains some arsenic ions. In order to further remove these arsenic ions, they are introduced into reaction tank B through a water pump and pipeline, and air is introduced into it while controlling the pH of the solution to 2.5 to generate ferric arsenate and obtain a solid-liquid mixture.

[0069] (4) Introduce the solid-liquid mixture obtained in step (3) into a superconducting strong magnetic field, and promote the arsenite ion / Fe ratio in the mixture by controlling the magnetic field induction intensity. 2+ It undergoes a rapid oxidation reaction with O2 in the air, with a reaction time of 0.5 hours, while simultaneously accelerating the precipitation rate of ferric arsenate, thus achieving efficient removal of arsenic ions from wastewater. The final concentration of arsenic ions in the treated water is 0.28 mg / L, which is lower than the Integrated Wastewater Discharge Standard (GB8978-1996).

[0070] (5) The treated water obtained in step (4) is introduced into reaction tank C, and lime milk is added to it. The final pH of the solution is controlled to be 10, and finally industrial discharge deep purified water and refined gypsum products are obtained, realizing deep purification of waste acid and effective recovery and utilization of sulfate ions.

[0071] In step (2), the concentration of arsenic ions in the waste acid is 26 g / L, and the addition ratio of pyrite to waste acid is 2:1 (FeS2:As molar ratio).

[0072] The air flow rate in step (3) is 120 m³ / h. 3 / h.

[0073] In step (4), the magnetic induction intensity is 4500mT, and the effluent can be recycled as an acid washing medium for arsenic-containing flue gas, reducing the amount of spray water used in the flue gas acid washing process.

[0074] The industrial wastewater obtained in step (5) meets the comprehensive industrial wastewater discharge standard (chemical composition is shown in Table 5) and can be reused; the purity of CaSO4 in the refined gypsum product reaches more than 97.3%.

[0075] Table 4

[0076] element As <![CDATA[H2SO4]]> Zn Fe Sb Mg Pb Concentration (mg / L) 26000 54000 19.65 34.76 8.34 8.54 16.34 element Ni Cd Hg Cl F Cr Cu Concentration (mg / L) 9.34 11.87 1.76 598.46 389.34 2.09 22.63

[0077] Table 5

[0078] element As F Zn Fe Sb Mg Pb Concentration (mg / L) 0.15 0.98 0.01 17.43 0.01 0.01 0.02

[0079] Example 3

[0080] The specific steps are as follows:

[0081] (1) Crushing and grinding pyrite to below 400 mesh, accounting for 20%, is beneficial to increasing the reaction area with the dirty acid;

[0082] (2) Add an appropriate amount of pyrite to the closed reaction tank A as S. - / Fe 2+ Arsenic precipitation agent was introduced into reaction tank A via a water pump and pipeline, along with waste acid (chemical composition shown in Table 6). The reaction was carried out for 0.9 hours at an ultrasonic power of 200W, a stirring speed of 180 r / min, and a reaction temperature of 23℃. Under these conditions, pyrite rapidly dissolved, releasing sulfur. - and Fe 2+ Ions, of which S - The ions will react directly with the trivalent arsenic ions in the waste acid to form arsenic sulfide precipitate;

[0083] (3) The waste acid after step (2) still contains some arsenic ions. In order to further remove these arsenic ions, they are introduced into reaction tank B through a water pump and pipeline, and air is introduced into it and the pH of the solution is controlled at 3.5 to create favorable conditions for the synthesis of ferric arsenate.

[0084] (4) Introduce the solid-liquid mixture obtained in step (3) into a superconducting strong magnetic field, and promote the arsenite ion / Fe ratio in the mixture by controlling the magnetic field induction intensity. 2+ It undergoes a rapid oxidation reaction with O2 in the air, with a reaction time of 0.2 hours, while simultaneously accelerating the precipitation rate of ferric arsenate, thus achieving efficient removal of arsenic ions from wastewater. The final concentration of arsenic ions in the treated water is 0.36 mg / L, which is lower than the Integrated Wastewater Discharge Standard (GB8978-1996).

[0085] (5) The treated water obtained in step (4) is introduced into reaction tank C, and lime milk is added to it. The final pH of the solution is controlled to be 8, and finally industrial discharge deep purified water and refined gypsum products are obtained, realizing deep purification of waste acid and effective recovery and utilization of sulfate ions.

[0086] In step (2), the concentration of arsenic ions in the waste acid is 11 g / L, and the addition ratio of pyrite to waste acid is 1.5:1 (FeS2:As molar ratio).

[0087] The air flow rate in step (3) is 150 m³ / h. 3 / h.

[0088] In step (4), the magnetic induction intensity is 3200mT, and the effluent can be recycled as an acid washing medium for arsenic-containing flue gas, reducing the amount of spray water used in the flue gas acid washing process.

[0089] The industrial wastewater obtained in step (5) meets the comprehensive industrial wastewater discharge standards (chemical composition shown in Table 7) and can be reused; the CaSO4 purity in the refined gypsum product reaches over 98.8%, and its physical sample and microstructure are shown in Table 7. Figure 1 and Figure 2 As shown. By Figure 1 It can be seen that the refined plaster product is white and granular, made from... Figure 2 It can be seen that the refined gypsum product has a cuboid crystal structure.

[0090] Table 6

[0091]

[0092]

[0093] Table 7

[0094] element As Cl Zn Fe F Mg Pb Concentration (mg / L) 0.12 0.98 0.01 4.34 0.89 0.01 0.01

[0095] Comparative Example 1

[0096] The other experimental steps and conditions are the same as in Example 3, except that step (2) does not involve ultrasonic waves.

[0097] Comparative Example 2

[0098] Other experimental steps and conditions are the same as in Example 3, except that step (4) does not involve a superconducting strong magnetic field.

[0099] Comparative Example 3

[0100] The other experimental steps and conditions are the same as in Example 3, except that there is no ultrasonic wave in step (2) and no superconducting strong magnetic field in step (4).

[0101] Table 8 shows the effects of pyrite on the residual arsenic ion concentration in treated water and the CaSO4 purity in refined gypsum products with and without external field application. The data in Table 8 indicate that, compared to the absence of external field application, the simultaneous introduction of ultrasound and a superconducting strong magnetic field into the reaction system significantly increased the arsenic removal efficiency of pyrite in high-arsenic wastewater, and also improved the CaSO4 purity in the prepared refined gypsum products. This suggests that external field assistance is beneficial for enhancing the treatment of high-arsenic wastewater with pyrite.

[0102] Table 8

[0103]

[0104] In this context, √ represents an external field effect, and × represents no external field effect.

[0105] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for treating high-arsenic acid pollution using pyrite with ultrasound-assisted superconducting strong magnetic field enhancement, characterized in that, The method includes: S1. Crush and grind pyrite to obtain pyrite arsenic precipitation agent; S2. Add arsenic precipitation agent to the waste acid and perform ultrasonic reaction while stirring until arsenic sulfide precipitate is generated. Separate the reactants into solid and liquid to obtain arsenic sulfide precipitate and separation liquid. S3. Air is introduced into the separation liquid and the pH value of the separation liquid is controlled at 0.5~3.5 to generate ferric arsenate and obtain a solid-liquid mixture; S4. The solid-liquid mixture obtained in step S3 is placed in a superconducting strong magnetic field, and air is continuously introduced to carry out the oxidation reaction, so that the arsenite ions / Fe in the solid-liquid mixture... 2+ It undergoes a rapid oxidation reaction with O2 in the air, accelerating the reaction of arsenate ions with Fe. 3+ Ferric arsenate precipitate is generated. After the reaction is completed, the reactants are separated into solid and liquid components to obtain ferric arsenate precipitate and treated water. S5. Add lime milk to the treated water obtained in step S4, and control the final pH of the solution to 8-12 to finally obtain industrial wastewater and gypsum. In step S2, the ultrasonic power is 50~400W and the stirring speed is 160~240r / min; The magnetic induction intensity of the superconducting strong magnetic field in step S4 is (2.0~4.5)×10. 3 The oxidation reaction time is 0.02~0.5h; the resulting treated water can be recycled as an acid washing medium for arsenic-containing flue gas.

2. The method for treating high-arsenic acid pollution using pyrite with ultrasound synergistic with a superconducting strong magnetic field as described in claim 1, characterized in that, In step S1, the S content of pyrite is ≥45%, and the Fe content is ≥45%; the grinding is to grind to below 400 mesh.

3. The method for treating high-arsenic acid pollution using pyrite with ultrasound synergistic with a superconducting strong magnetic field as described in claim 1, characterized in that, In step S2, the concentration of arsenic ions in the polluted acid is greater than 0.5 g / L.

4. The method for treating high-arsenic acid pollution using pyrite with ultrasound synergistic with a superconducting strong magnetic field as described in claim 1, characterized in that, In step S2, the addition ratio of arsenic precipitation agent to waste acid is FeS2:As molar ratio (0.5~2):

1.

5. The method for treating high-arsenic acid pollution using pyrite with ultrasound-assisted superconducting strong magnetic field enhancement according to claim 1, characterized in that, In step S2, the reaction temperature is 23~50℃ and the reaction time is 0.05~0.9h.

6. The method for treating high-arsenic acid pollution using pyrite with ultrasound synergistic with a superconducting strong magnetic field as described in claim 1, characterized in that, In step S3, the air flow rate is 80~150m³ / h. 3 / h.

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