Arsenic removal method and reaction system of high-arsenic waste liquid by gas-liquid sulfidation

Abstract

The application provides a gas-liquid sulfuration arsenic removal method and a reaction system for high-arsenic waste liquid, and the method comprises the following steps: S1, providing an additive; the additive comprises sodium bisulfite; S2, mixing the high-arsenic waste liquid and the additive to obtain a first treatment liquid; S3, continuously introducing H2S micro-bubbles into the first treatment liquid, and obtaining a second treatment liquid after the introduction of the H2S micro-bubbles is completed; the time length of the introduction of the H2S micro-bubbles is not less than 10 min; the first treatment liquid is secondly mixed during the introduction of the H2S micro-bubbles; and the first treatment liquid is controlled to circulate backflow during the second mixing; the high-arsenic waste liquid contains pentavalent arsenic; and S4, performing solid-liquid separation on the second treatment liquid to obtain an arsenic removal separation liquid. The application can realize rapid and efficient removal of pentavalent arsenic, reduce the concentration of the pentavalent arsenic to below 50 mg / L, and will not affect the removal efficiency of trivalent arsenic.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of heavy metal pollution treatment, and particularly relates to a gas-liquid sulfidation arsenic removal method and reaction system for high-arsenic waste liquid. BACKGROUND

[0002] The development of copper metallurgy technology has experienced a long process, but so far, the smelting of copper is still mainly based on fire smelting, and the output accounts for about 85% of the world's copper output; in the copper production process, a large amount of acid flue gas will be generated, and after the flue gas is removed, a large amount of waste acid will be left; the waste acid contains a large amount of heavy metals, especially arsenic, which belongs to smelting high-arsenic waste liquid; if there is no effective treatment method, it will not only endanger the environmental safety, but also cause incalculable economic losses.

[0003] Sulfidation arsenic removal as a new purification process gradually rises in the copper smelting industry and is widely used. Gas-liquid sulfidation arsenic removal is to add hydrogen sulfide gas to the solution to remove arsenic, and when hydrogen sulfide is used to treat industrial wastewater, the reaction process can be accurately controlled by controlling the amount of hydrogen sulfide added, and the selective removal of metal ions can be realized. The treatment of copper electrolysis arsenic-containing waste liquid by gas-liquid sulfidation technology is one of the most potential ways to realize source reduction and clean production in the copper industry. However, from the industrial application situation, there are still many problems that have not been solved, such as the slow reaction rate of ordinary gas-liquid sulfidation reaction, and in industry, excessive addition of hydrogen sulfide is often used, which makes the sulfur content too high, increases the cost of enterprises, and easily leads to the presence of a large amount of hydrogen sulfide gas in the production site, which poses a major threat to the personal safety of workers. In addition, smelting high-arsenic waste liquid usually contains pentavalent arsenic and trivalent arsenic, and although the hydrogen sulfide arsenic removal method can remove some pentavalent arsenic, it will still contain a high concentration of pentavalent arsenic in the separated liquid.

[0004] Therefore, it is necessary to provide a gas-liquid sulfidation arsenic removal method and reaction system for high-arsenic waste liquid to solve or at least alleviate the technical defects of how to efficiently remove pentavalent arsenic or how to simultaneously and efficiently remove pentavalent arsenic and trivalent arsenic. SUMMARY

[0005] The main purpose of the present application is to provide a gas-liquid sulfidation arsenic removal method and reaction system for high-arsenic waste liquid, which aims to solve or at least alleviate the technical problems of how to efficiently remove pentavalent arsenic or how to simultaneously and efficiently remove pentavalent arsenic and trivalent arsenic.

[0006] To achieve the above-mentioned purpose, the present application provides a gas-liquid sulfidation arsenic removal method for high-arsenic waste liquid, comprising the following steps:

[0007] S1, providing an additive; the additive comprises sodium bisulfite;

[0008] S2, mixing high-arsenic waste liquid and the additive to obtain a first treatment liquid;

[0009] S3, continuously introducing H2S micro-bubbles into the first treatment liquid, and obtaining a second treatment liquid after the introduction of the H2S micro-bubbles is completed;

[0010] The time length for introducing the H2S micro-bubbles is not less than 10 minutes; the second mixing is performed on the first treatment liquid during the introduction of the H2S micro-bubbles; and the circulation backflow of the first treatment liquid is controlled during the second mixing;

[0011] The high-arsenic waste liquid contains pentavalent arsenic; and the molar ratio of the sodium bisulfite to the pentavalent arsenic is 0.5-2:1.

[0012] S4, performing solid-liquid separation on the second treatment liquid to obtain an arsenic-removal separation liquid.

[0013] Further, the high-arsenic waste liquid further contains trivalent arsenic, and the molar ratio of the pentavalent arsenic to the trivalent arsenic is 0.8-1.2:0.8-1.2.

[0014] Further, the total concentration of arsenic elements in the high-arsenic waste liquid is 5-25 g / L; and the pH of the high-arsenic waste liquid is 1-2.

[0015] Further, the high-arsenic waste liquid includes smelting high-arsenic waste liquid; and the smelting high-arsenic waste liquid includes one or more of waste acid and copper electrolyte.

[0016] Further, the flow rate of the H2S micro-bubbles is 4-6 m 3 / h.

[0017] Further, the H2S is generated in a hydrogen sulfide synthesis device, the hydrogen sulfide synthesis device supplies gas to a micro-bubble mechanism through a hydrogen sulfide buffer tank, the micro-bubble mechanism is exposed to the first treatment liquid; and the H2S is converted into the H2S micro-bubbles by the micro-bubble mechanism.

[0018] Further, the time length for introducing the H2S micro-bubbles is 20-120 minutes.

[0019] Further, the additive further includes ferrous ammonium sulfate; and the molar ratio of the sodium bisulfite to the ferrous ammonium sulfate is 1.5-5:1.

[0020] Further, the first mixing and the second mixing are both performed at room temperature.

[0021] The application also provides a reaction system for gas-liquid sulfidation arsenic removal of high-arsenic waste liquid, which comprises a hydrogen sulfide synthesis device, a hydrogen sulfide buffer tank, a micro-bubble mechanism, a sulfidation reaction device and a reflux device; the hydrogen sulfide synthesis device, the hydrogen sulfide buffer tank and the micro-bubble mechanism are sequentially connected through a gas guide pipe, the micro-bubble mechanism is arranged in the sulfidation reaction device, the reflux device has a liquid inlet and a liquid outlet, and the liquid inlet and the liquid outlet are connected with the sulfidation reaction device.

[0022] The reaction device also comprises a control unit, which executes the gas-liquid sulfidation arsenic removal method as described above.

[0023] Compared with the prior art, the application has at least the following advantages:

[0024] The application provides a gas-liquid sulfidation arsenic removal method for high-arsenic waste liquid, which can quickly and efficiently remove pentavalent arsenic and reduce the concentration of pentavalent arsenic from a high concentration to below 50 mg / L; at the same time, the application does not affect the removal efficiency of trivalent arsenic and can still ensure that the concentration of trivalent arsenic is in a low range. From another aspect, when removing trivalent arsenic, even if only reacting for about 20 minutes after combining sodium bisulfite and ferrous ammonium sulfate, the application can also simultaneously achieve significant reduction of pentavalent arsenic (when reacting for 20 minutes, the concentration of pentavalent arsenic is reduced by nearly 90%).

[0025] By introducing sodium bisulfite and ferrous ammonium sulfate into the gas-liquid sulfidation arsenic removal system, controlling the introduction of H2S micro-bubbles, and simultaneously performing second mixing and circulating reflux during the introduction process, the application can strengthen the removal effect of pentavalent arsenic in high-arsenic waste liquid, shorten the removal time of arsenic (pentavalent arsenic and trivalent arsenic) in the system, and increase the arsenic removal rate. In addition, by controlling the introduction of H2S micro-bubbles and adding a reflux device, the application can also increase the contact area and contact time of high-arsenic waste liquid with sulfidation agent, reduce the amount of H2S used, and reduce the processing cost; the application can also avoid the production of a large amount of hydrogen sulfide gas on site. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0027] Figure 1 It is a flowchart of the gas-liquid sulfidation arsenic removal method for high-arsenic waste liquid in the application;

[0028] Figure 2The concentration of pentavalent arsenic in the separated liquid corresponding to different reaction times in the embodiment 1, the embodiment 2 and the comparative example 1 of the present application;

[0029] In the figure, the concentration of pentavalent arsenic at 0 min corresponds to the initial concentration of pentavalent arsenic in the high-arsenic waste liquid; the concentration at other times is the concentration of pentavalent arsenic in the separated liquid at the corresponding reaction time; the reaction time is taken as the starting time when the hydrogen sulfide micro-bubbles start to be introduced into the first treatment liquid; NaHSO3+(NH4)2Fe(SO4)2 refers to the embodiment 1, NaHSO3 refers to the embodiment 2, and no additive refers to the comparative example 1;

[0030] Figure 3 The concentration of trivalent arsenic in the separated liquid corresponding to different reaction times in the embodiment 1, the embodiment 2 and the comparative example 1 of the present application;

[0031] In the figure, the concentration of trivalent arsenic at 0 min corresponds to the initial concentration of trivalent arsenic in the high-arsenic waste liquid; the concentration at other times is the concentration of trivalent arsenic in the separated liquid at the corresponding reaction time; the reaction time is taken as the starting time when the hydrogen sulfide micro-bubbles start to be introduced into the first treatment liquid; NaHSO3+(NH4)2Fe(SO4)2 refers to the embodiment 1, NaHSO3 refers to the embodiment 2, and no additive refers to the comparative example 1;

[0032] Figure 4 The XRD figures of the As(III) arsenic precipitation product in the analysis example 1 and the As(V) arsenic precipitation product in the analysis example 2 of the present application; in the figure, (a) corresponds to the As(III) arsenic precipitation product at different reaction times, and (b) corresponds to the As(V) arsenic precipitation product at different reaction times;

[0033] Figure 5 The SEM&EDS figures of the As(III) arsenic precipitation product in the analysis example 1 of the present application;

[0034] Figure 6 The SEM&EDS figures of the As(V) arsenic precipitation product in the analysis example 2 of the present application.

[0035] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0037] And, the technical solutions among the various embodiments of the present application can be combined with each other, but it must be based on the fact that a person having ordinary skill in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0038] When the embodiments give a numerical range, it should be understood that, unless otherwise stated by the present application, both endpoints of each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are used in the same manner as the present technical field of the skilled person and the description of the present application, and any method, equipment and material of the prior art similar or equivalent to the method, equipment and material described in the embodiments of the present application can be used to realize the present application. In the embodiments 1-2 and comparative example 1 of the present application, the high-arsenic waste liquid is prepared from sodium arsenate and sodium arsenite.

[0039] Referring to Figure 1 As shown, the present application provides a gas-liquid sulfidation arsenic removal method for high-arsenic waste liquid, comprising the steps of:

[0040] S1, providing an additive; the additive comprises sodium bisulfite.

[0041] S2, first mixing the high-arsenic waste liquid and the additive to obtain a first treatment liquid.

[0042] S3, continuously introducing H2S micro-bubbles into the first treatment liquid to form a gas-liquid sulfidation arsenic removal system; after the introduction of the H2S micro-bubbles is completed, a second treatment liquid is obtained.

[0043] The present application greatly enhances the gas-liquid sulfidation arsenic removal efficiency of the high-arsenic waste liquid by introducing the additive, greatly shortens the arsenic removal time, and the process operation is simple.

[0044] In the present application, the duration of the first mixing can be 10-20 min; the rotation speed of the first mixing can be 150-300 r / min.

[0045] In the present application, the duration of the introduction of the H2S micro-bubbles is not less than 10 min or not less than 15 min or not less than 120 min; further, the duration of the introduction of the H2S micro-bubbles is 20-120 min; preferably, the duration of the introduction of the H2S micro-bubbles is 20-25 min or 110-120 min, or 120-130 min. The flow rate of the introduction of the H2S micro-bubbles can be 4-6 m 3 / h, the H2S micro-bubbles are introduced into the first treatment liquid at room temperature; the flow rate is the flow rate of the H2S gas into the first treatment liquid.

[0046] In the present application, the H2S gas is generated in a hydrogen sulfide synthesis device, the hydrogen sulfide synthesis device is connected with a micro-bubble mechanism through a hydrogen sulfide buffer tank, the micro-bubble mechanism is exposed to the first treatment liquid; the H2S gas is converted into H2S micro-bubbles through the micro-bubble mechanism, and the micro-bubble mechanism can be bubble stone, and the bubble diameter generated by the bubble stone is 0.1-2 mm.

[0047] In the hydrogen sulfide synthesis device, the sulfuric acid solution is continuously added into the NaHS solution, so that H2S is continuously generated; and when the generation of H2S is completed, the addition of the sulfuric acid solution is stopped. In the present application, the H2S generated in the hydrogen sulfide synthesis device enters the hydrogen sulfide buffer tank, and then enters the bubble mechanism to form H2S micro-bubbles.

[0048] In the present application, the hydrogen sulfide synthesis device generates H2S by the following method: an appropriate amount of NaHS solution is taken into a reaction container (a three-necked flask) of the hydrogen sulfide synthesis device, and an appropriate amount of 50% (mass fraction) dilute sulfuric acid solution is taken into a dropping funnel, a 50% (mass fraction) dilute sulfuric acid solution is added into the reaction container of the hydrogen sulfide synthesis device by rotating the dropping funnel stopcock, and the addition speed is 30-45 drops / min; and stirring is carried out during the addition, and the stirring speed is 200 r / min.

[0049] In the present application, the first treatment liquid is subjected to second mixing during the process of introducing the H2S micro-bubbles (during the reaction process); the second mixing speed can be 150-300 r / min; and the first mixing and the second mixing are both carried out at room temperature.

[0050] During the second mixing, the first treatment liquid is controlled to circulate backflow. The circulation backflow is that the first treatment liquid is continuously flowed out of and flowed into the reaction container of the sulfuration reaction device (the first treatment liquid is in the reaction container of the sulfuration reaction device) through a backflow device (a peristaltic pump and a liquid guide pipe), so that the first treatment liquid is controlled to circulate flow during the reaction process. In the present application, the circulation backflow of the first treatment liquid can enhance the utilization efficiency of the sulfuration agent in the gas-liquid sulfuration arsenic removal system, increase the contact area and contact time of the high-arsenic waste liquid and the sulfuration agent, and strengthen the removal effect of pentavalent arsenic in the high-arsenic waste liquid.

[0051] As a specific description, in the present application, the peristaltic pump speed is 300-400 r / min, and the flow rate of the first treatment liquid during the circulation backflow is 1400-1800 mL / min.

[0052] As an illustration of the high-arsenic waste liquid, the high-arsenic waste liquid contains pentavalent arsenic; the concentration of pentavalent arsenic in the high-arsenic waste liquid can be 5-15 g / L or 8-11 g / L; the molar ratio of sodium bisulfite to pentavalent arsenic is 0.5-2:1, further 0.5-0.8:1. Preferably, to accelerate the processing speed of pentavalent arsenic, the additive further comprises ferrous ammonium sulfate; the molar ratio of sodium bisulfite to ferrous ammonium sulfate is 1.5-5:1, further 1.5-2.5:1; the additive containing sodium bisulfite and ferrous sulfate can be referred to as a compound reducing agent.

[0053] The high-arsenic waste liquid also contains trivalent arsenic, and the molar ratio of pentavalent arsenic to trivalent arsenic is 0.8-1.2:0.8-1.2. In the high-arsenic waste liquid, the total concentration of arsenic elements is 5-25 g / L or 15-25 g / L; the pH of the high-arsenic waste liquid is 1-2; the pH of the high-arsenic waste liquid can be controlled by adding acid (sulfuric acid). In the present application, the high-arsenic waste liquid can include or be a smelting high-arsenic waste liquid; the smelting high-arsenic waste liquid includes one or more of contaminated acid and copper electrolyte.

[0054] S4, solid-liquid separation is performed on the second treatment liquid to obtain an arsenic-removed separation liquid (purified liquid) and an arsenic-containing separation residue (arsenic sulfide residue); in industrial applications, the arsenic-containing separation residue can be returned to the sulfidation reaction device.

[0055] It should be understood that in the present application, the number of solid-liquid separation can be determined according to actual conditions, although two solid-liquid separations are performed in the present application embodiment 1-2, but the second solid-liquid separation is mainly for deep filtration, to facilitate the detection of pentavalent arsenic and trivalent arsenic.

[0056] The present application also provides a reaction system for gas-liquid sulfidation arsenic removal of high-arsenic waste liquid, the reaction system includes hydrogen sulfide synthesis device, hydrogen sulfide buffer tank, micro-bubble mechanism, sulfidation reaction device and reflux device; the hydrogen sulfide synthesis device, the hydrogen sulfide buffer tank and the micro-bubble mechanism are connected in sequence through the gas guide pipe, the micro-bubble mechanism is placed in the interior of the sulfidation reaction device, the reflux device has liquid inlet and liquid outlet, the liquid inlet and the liquid outlet are connected with the sulfidation reaction device; the reflux device includes peristaltic pump and liquid guide pipe. The reaction device further includes a control unit, which executes any of the above-mentioned gas-liquid sulfidation arsenic removal methods.

[0057] The present application utilizes the additive composed of sodium bisulfite and ferrous ammonium sulfate, and carries out the reaction under the conditions of normal temperature, pH=1-2 and low H2S input amount, simultaneously utilizes the circulation of high-arsenic waste liquid and arsenic sulfide residue in the reaction device to increase the contact area and contact time of high-arsenic waste liquid and sulfidizing agent. The present application can efficiently remove arsenic element from high-arsenic waste liquid, has simple operation, low raw material cost, strong arsenic removal effect, and can be applied to the fields of copper smelting, high-arsenic waste liquid treatment and environmental protection.

[0058] The following are specific examples of the present invention:

[0059] Example 1

[0060] A gas-liquid sulfidation arsenic removal method of high-arsenic waste liquid adopts the following steps:

[0061] S1, providing high-arsenic waste liquid and an additive.

[0062] In the embodiment, arsenic in the high-arsenic waste liquid exists in the form of pentavalent arsenic and trivalent arsenic, the concentration of pentavalent arsenic is 10692 mg / L, and the concentration of trivalent arsenic is 10594 mg / L; 200 mL of high-arsenic waste liquid is measured by a measuring cylinder, and the measured high-arsenic waste liquid is transferred to a reaction container (a three-necked flask) of a sulfidation reaction device by a glass rod, appropriate dilute sulfuric acid is added, and pH is adjusted to 1.

[0063] In the embodiment, the additive is composed of sodium bisulfite and ferrous ammonium sulfate; 1.85 g of sodium bisulfite and 2.93 g of ferrous ammonium sulfate are weighed by an electronic balance as the additive.

[0064] S2, the additive is poured into the reaction container containing the high-arsenic waste liquid, and stirring is carried out, the stirring speed is 200 r / min, after stirring at normal temperature for 10 min, a first treatment liquid is obtained; the three-necked flask is covered with a soft plug, and is fixed by an iron stand for standby.

[0065] S3, H2S is prepared by a hydrogen sulfide synthesis device, H2S gas generated in the hydrogen sulfide synthesis device enters a hydrogen sulfide buffer tank, and then flows to a bubble stone; the bubble stone is exposed to the first treatment liquid, and the H2S gas is converted into H2S micro-bubbles by the bubble stone; the H2S gas is continuously input into the first treatment liquid in the form of H2S micro-bubbles at normal temperature, so that the gas-liquid sulfidation arsenic removal reaction (carried out at normal temperature) occurs in the reaction container of the sulfidation reaction device; the input flow of the H2S micro-bubbles is 5 m 3 / h (input into the first treatment liquid).

[0066] After the reaction begins (the reaction start time is the initial time when H2S is introduced into the first treatment liquid), the first treatment liquid is stirred at room temperature, and the stirring speed is controlled at 200 r / min. In this embodiment, the reaction vessel of the sulfidation reaction device is connected to the inlet and outlet of the reflux device, which consists of a peristaltic pump and a liquid guide pipe. During the reaction, the first treatment liquid (referred to as the first treatment liquid before the gas flow ends) is circulated and refluxed during the gas-liquid sulfidation arsenic removal reaction through the reflux device. In this embodiment, the peristaltic pump speed is 350 r / min, and the flow rate of the first treatment liquid during circulation and reflux is 1600 mL / min.

[0067] When the reaction is terminated, the introduction of H2S microbubbles into the vulcanization reactor is stopped, and a second treatment liquid is obtained in the vulcanization reactor. The second treatment liquid is initially filtered with qualitative filter paper with a pore size of 30-50 micrometers to obtain a separation residue and a primary filtrate. The obtained primary filtrate is then deeply filtered with a filter head with a pore size of 0.22 micrometers to obtain a separation liquid (secondary filtrate). The arsenic content of the separation liquid is determined.

[0068] See Figure 2 As shown in this embodiment, the concentration of pentavalent arsenic in the separation solution was 1160 mg / L after 20 min of reaction; 349 mg / L after 1 h of reaction; and 48 mg / L after 2 h of reaction.

[0069] See Figure 3 As shown, the concentration of trivalent arsenic in the separation solution was 25 mg / L after 10 min of reaction; and 14 mg / L after 20 min of reaction.

[0070] Example 2

[0071] Compared to Example 1, this embodiment changed the batch of the high-arsenic waste liquid and adjusted the additive to sodium bisulfite (without adding ferrous ammonium sulfate). The amount of sodium bisulfite used was 2.32g, while other conditions remained unchanged. The arsenic in the high-arsenic waste liquid existed in the form of pentavalent and trivalent arsenic, with a concentration of 10790mg / L for pentavalent arsenic and 10483mg / L for trivalent arsenic.

[0072] See Figure 2 As shown in this embodiment, the concentration of pentavalent arsenic in the separation solution was 4097 mg / L after 20 min of reaction; 336 mg / L after 1 h of reaction; and 49 mg / L after 2 h of reaction.

[0073] See Figure 3As shown, the concentration of trivalent arsenic in the separation liquid was 28 mg / L at 10 min of reaction; and the concentration of trivalent arsenic in the separation liquid was 13 mg / L at 20 min of reaction.

[0074] Comparative Example 1

[0075] The comparative example 1 was compared with the example 1, the preparation batch of high-arsenic waste liquid was changed, and no additive was added, the high-arsenic waste liquid was directly used as the first treatment liquid, and other conditions were unchanged; wherein, the arsenic in the high-arsenic waste liquid existed in the form of pentavalent arsenic and trivalent arsenic, the concentration of pentavalent arsenic was 7266 mg / L, and the concentration of trivalent arsenic was 7194 mg / L.

[0076] Referring to Figure 2 As shown, in the comparative example, the concentration of pentavalent arsenic in the separation liquid was 389 mg / L at 2 h of reaction.

[0077] Referring to Figure 3 As shown, in the comparative example, the concentration of trivalent arsenic in the separation liquid was 10 mg / L at 20 min of reaction.

[0078] Analytical Example 1

[0079] The comparative example 1 was compared with the example 1, the preparation batch of high-arsenic waste liquid was changed, and no additive was added, the high-arsenic waste liquid was directly used as the first treatment liquid, and other conditions were unchanged; wherein, the arsenic in the high-arsenic waste liquid existed in the form of pentavalent arsenic and trivalent arsenic, the concentration of pentavalent arsenic was 7266 mg / L, and the concentration of trivalent arsenic was 7194 mg / L.

[0080] The separation residue obtained in the analysis example was recorded as As(III) arsenic precipitation product. In the analysis example, the phase analysis of the As(III) arsenic precipitation product obtained after 5 min, 10 min and 20 min of reaction was shown in (a) of Figure 4 As shown, the samples of different reaction times were not much different, and peaks appeared at 18°, 33° and 56°, the diffraction peaks were weak and wide, and therefore were in amorphous state. After comparison, the characteristic peaks were similar to those of As2S3; therefore, it was speculated that As2S3 was contained in the sulfurized precipitation product of As(III).

[0081] In the analysis example, the SEM&EDS analysis of the As(III) arsenic precipitation product obtained after 20 min of reaction was shown in Figure 5 As shown, it can be seen that the As(III) arsenic precipitation product was easy to agglomerate into blocks, the surface scanning result showed that S:As in the As(III) arsenic precipitation product was about 1.5, which was consistent with the atomic ratio in As2S3, and it was speculated that the product was single As2S3 precipitation.

[0082] Analytical Example 2

[0083] In the analysis example, compared with the comparative example 1, the high arsenic waste liquid is adjusted to a pentavalent arsenic simulation liquid, and other conditions remain unchanged; wherein the pentavalent arsenic simulation liquid is prepared by sodium arsenate, and the concentration of pentavalent arsenic is 7000mg / L.

[0084] The separation residue obtained in the analysis example is denoted as As(V) arsenic precipitation product. In the analysis example, the phase analysis of the As(V) arsenic precipitation product obtained after 1h, 1.5h and 2h of reaction is shown in part (b) of Figure 6, and the samples of different reaction times have little difference, all appearing peak shape at 18°, 33° and 56°, and the diffraction peak is weak and wide, so it is amorphous. After comparison, it is similar to the characteristic peak of As2S3; therefore, it is speculated that As2S3 is contained in the sulfidation precipitation product of As(V). Figure 4

[0085] In the analysis example, the SEM&EDS analysis of the As(V) arsenic precipitation product obtained after 2h of reaction is shown in Figure 7. Figure 6 As can be seen from Figure 7, the As(V) arsenic precipitation product has good dispersibility, and the face scanning result shows that S:As in the As(V) arsenic precipitation product is about 2.6, and it is speculated that the product is composed of As2S3 and S, but there is no obvious characteristic peak of S in the XRD of As(V).

[0086] In the above technical solution of the present application, the above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made under the technical concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.​

Claims

1. A method for removing arsenic from a high-arsenic waste solution by gas-liquid sulfidation, characterized by, The method comprises the steps of: S1, providing an additive; the additive comprises sodium bisulfite and ferrous ammonium sulfate; the molar ratio of the sodium bisulfite to the ferrous ammonium sulfate is 1.5-5:1; S2, mixing the high-arsenic waste liquid and the additive to obtain a first treatment liquid; the first mixing is performed for 10-20 min; S3, continuously introducing H2S micro-bubbles into the first treatment liquid; the H2S micro-bubbles are introduced for 20-25 min; after the introduction of the H2S micro-bubbles is completed, a second treatment liquid is obtained; During the introduction of the H2S micro-bubbles, the first treatment liquid is subjected to a second mixing; and during the second mixing, the first treatment liquid is controlled to circulate backflow; The high-arsenic waste liquid contains pentavalent arsenic and trivalent arsenic; the molar ratio of the pentavalent arsenic to the trivalent arsenic is 0.8-1.2:0.8-1.2; the concentration of the pentavalent arsenic in the high-arsenic waste liquid is 5-15 g / L; the molar ratio of the sodium bisulfite to the pentavalent arsenic is 0.5-2:1; S4, performing solid-liquid separation on the second treatment liquid to obtain an arsenic-removal separation liquid.

2. The gas-liquid sulfidation arsenic removal process of claim 1, wherein, The pH of the high-arsenic waste liquid is 1-2.

3. The gas-liquid sulfidation arsenic removal process of claim 1, wherein, The high-arsenic waste liquid comprises smelting high-arsenic waste liquid; the smelting high-arsenic waste liquid comprises one or more of waste acid and copper electrolyte.

4. The gas-liquid sulfidation arsenic removal process of claim 1 wherein, The flow rate of the H2S microbubbles is 4-6 m 3 / h.

5. The gas-liquid sulfidation arsenic removal process of claim 1 wherein, The H2S is generated in a hydrogen sulfide synthesis device; the hydrogen sulfide synthesis device supplies gas to a micro-bubble mechanism through a hydrogen sulfide buffer tank; the micro-bubble mechanism is exposed to the first treatment liquid; the H2S is converted into H2S micro-bubbles by the micro-bubble mechanism.

6. The gas-liquid sulfidation arsenic removal process of claim 1 wherein, The first mixing and the second mixing are both performed at room temperature.

7. A reaction system for gas-liquid sulfidation arsenic removal of high arsenic waste liquid, characterized in that, The reaction system comprises a hydrogen sulfide synthesis device, a hydrogen sulfide buffer tank, a micro-bubble mechanism, a sulfuration reaction device, and a backflow device; the hydrogen sulfide synthesis device, the hydrogen sulfide buffer tank, and the micro-bubble mechanism are connected in sequence through a gas guide pipe; the micro-bubble mechanism is placed inside the sulfuration reaction device; the backflow device has a liquid inlet and a liquid outlet; both the liquid inlet and the liquid outlet are connected to the sulfuration reaction device; The reaction device further comprises a control unit; the control unit performs the gas-liquid sulfuration arsenic-removal method according to any one of claims 1-6.

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