A method for removing thallium based on thallium-containing wastewater containing chlorine

Abstract

The application provides a method for removing thallium based on thallium-containing and chlorine-containing wastewater, comprising the following steps: S1, providing thallium-containing and chlorine-containing wastewater to be treated; S2, mixing the thallium-containing and chlorine-containing wastewater with a thallium removal agent to obtain a first treatment liquid; the thallium removal agent comprises polysulfide; S3, mixing the first treatment liquid with a multi-effect auxiliary agent to obtain a second treatment liquid; the multi-effect auxiliary agent comprises a first flocculating agent and manganese salt; S4, mixing a second flocculating agent into the second treatment liquid and standing to obtain a third treatment liquid; S5, performing solid-liquid separation treatment on the third treatment liquid to obtain thallium-containing precipitate and thallium removal separation liquid. The application can deeply purify thallium in thallium-containing and chlorine-containing wastewater and reduce the introduction of new impurities.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of wastewater treatment, and particularly relates to a method for removing thallium based on thallium-containing wastewater. BACKGROUND

[0002] Thallium (Tl) is a typical toxic heavy metal, which is accumulative and is one of the 13 priority metal pollutants recognized in the world. Thallium mainly causes toxic effects on the nervous system of human body, and the minimum lethal dose is 10-15 mg / kg. Thallium and thallium compounds also have mutagenic and carcinogenic effects. The toxic effect of thallium on human body is much stronger than that of lead, cadmium and mercury, and is close to that of arsenic. Thallium is often associated with iron, zinc, lead and other metal sulfide ores, and a large amount of thallium is produced and discharged in the process of steel smelting and non-ferrous metal smelting. In order to strengthen the control and management of thallium, in recent years, the state policy, standards and industry and local standards have further improved the requirements for thallium emission concentration, and the thallium emission standards of multiple industries and local industrial wastewater are 5 μg / L.

[0003] The existing thallium removal technology focuses on the adsorption of thallium in natural water such as surface water and simulated water, but the thallium form and thallium concentration and other water quality conditions are quite different from those of industrial wastewater, which makes it difficult for the existing adsorbent to adapt to the characteristics of high fluorine and chlorine and high thallium concentration in industrial wastewater. The commonly used thallium removal method in industry is oxidation precipitation. Because Tl usually exists in the form of Tl(I) in water, Tl(I) is difficult to be adsorbed by conventional materials and does not form precipitable hydroxide, and it is more difficult to remove than Tl(III). Therefore, an oxidizing agent is usually added to oxidize Tl(I) which is easily soluble in water into Tl(III), and Tl(III) generates hydroxide under alkaline conditions and can dehydrate to form Tl2O3 precipitate; however, when the wastewater contains a large amount of chloride ions, Tl(I) is oxidized to Tl(III), which rapidly forms a very stable complex [TlCl4 - ] with Cl - ] and is difficult to remove by precipitation, so the commonly used oxidation precipitation method is not suitable for wastewater with high chlorine and thallium. Sulfidation precipitation method forms Tl2S precipitate by adding sulfide, which is limited by solubility product. In theory, the thallium concentration in wastewater can be reduced to about 45 μg / L at most. The existing adsorbent is greatly affected by coexisting ions. Therefore, the above methods are difficult to meet the increasingly strict emission requirements, and new thallium removal technology needs to be developed urgently.

[0004] The Chinese patent application with the publication number CN115947436A discloses a method for removing thallium in lead-zinc smelting wastewater, which reduces the thallium concentration in smelting wastewater by preparing a thallium removal agent based on thiol, hydroxyl and carboxyl coordination groups and adding the thallium removal agent to the smelting wastewater, so as to achieve standard discharge. The Chinese patent application with the publication number CN105254075A discloses a heavy metal capturing agent and a method for removing thallium from sintering desulfurization wastewater, which removes thallium in desulfurization wastewater by coagulation, adding a capturing agent and flocculation. Although the above patent applications achieve the removal of thallium, the initial thallium concentration of the above patent applications is low, and they do not process thallium with higher concentration. Moreover, the above patent applications do not achieve deep removal of thallium in the presence of a large amount of chloride ions and thallium ions.

[0005] Therefore, it is necessary to provide a method for removing thallium based on wastewater containing chlorine and thallium, so as to solve or at least alleviate the technical defect of how to deeply remove thallium in the presence of a large amount of chloride ions and thallium ions with high thallium ion concentration. SUMMARY

[0006] The main purpose of the present application is to provide a method for removing thallium based on wastewater containing chlorine and thallium, aiming to solve or at least alleviate the technical problem of how to deeply remove thallium in the presence of a large amount of chloride ions and thallium ions with high thallium ion concentration.

[0007] To achieve the above-mentioned purpose, the present application provides a method for removing thallium based on wastewater containing chlorine and thallium, comprising the steps of:

[0008] S1, providing wastewater containing chlorine and thallium to be treated;

[0009] S2, mixing the wastewater containing chlorine and thallium with a thallium removal agent to obtain a first treatment liquid; the thallium removal agent comprises polysulfide;

[0010] S3, mixing the first treatment liquid with a multi-effect auxiliary agent to obtain a second treatment liquid; the multi-effect auxiliary agent comprises a first flocculant and a manganese salt;

[0011] S4, mixing a second flocculant into the second treatment liquid and standing to obtain a third treatment liquid;

[0012] S5, performing solid-liquid separation treatment on the third treatment liquid to obtain a thallium-containing precipitate and a thallium removal separation liquid.

[0013] Further, the pH of the wastewater containing chlorine and thallium is greater than 11.

[0014] Further, the wastewater containing chlorine and thallium contains chlorine elements and thallium elements, the concentration of the chlorine elements is 5-200 g / L, and the concentration of the thallium elements is 5 ug / L-20 mg / L.

[0015] Further, the pH of the first treatment liquid is not less than 9.

[0016] Further, the mass-volume ratio of the polysulfide and the chlorinated and thallium-containing wastewater is 4-10 g / L.

[0017] Further, the thallium removal agent further comprises sodium sulfide and potassium sulfide; the mass ratio of the polysulfide, the sodium sulfide and the potassium sulfide is 50-1000:0.1-10:0.1-10; and the polysulfide comprises calcium polysulfide.

[0018] Further, the mass ratio of the first flocculant and the polysulfide is 1:1-8; and the mass ratio of the first flocculant and the manganese salt is 200:0.01-10.

[0019] Further, the first flocculant comprises one or more of polyaluminum ferric sulfate, polyaluminum ferric silicate, polyaluminum silicate sulfate, polyferric sulfate and polyaluminum chloride.

[0020] Further, the manganese salt comprises one or more of manganese sulfate, manganese chloride and manganese nitrate.

[0021] Further, the mass-volume ratio of the second flocculant and the chlorinated and thallium-containing wastewater is 0.01-0.1 g / L.

[0022] The second flocculant comprises one or more of anionic polyacrylamide, cationic polyacrylamide and neutral polyacrylamide.

[0023] The main technical principle of the present application comprises: when thallium is removed by oxidation, Tl(III) formed in the high-chlorine wastewater is easy to form a stable complex [TlCl4 - ] with Cl - in the solution and is difficult to remove in the form of precipitation. In the present application, polysulfide (S x 2- x=2-7, average 5) will undergo disproportionation to generate sulfide ions (S 2- ) and thiosulfate ions (S2O3 2- )(S5 2- +3OH - →S2O3 2- +3HS - ); the present application first adds polysulfide, sulfide ions (S 2- ) react with Tl(I) to generate Tl2S which is difficult to dissolve in water, and thiosulfate ions (S2O3 2- ) have strong reducing properties and can reduce Tl(III) and its [TlCl4 - ] complex to Tl(I), avoiding the influence of Cl - ; the Tl(I) produced by reduction further reacts with sulfide ions (S 2-) to generate Tl2S which is hardly soluble in water, thereby realizing preliminary removal of thallium. Then, a multi-effect additive is added, and a first flocculating agent in the multi-effect additive can generate hydroxide by chemical reaction, and the hydroxide can neutralize positive colloidal particles and surface active substances in water to adsorb suspended matters, thereby forming flocculation and precipitation; Mn(OH)2 generated by manganese ions under alkaline conditions is a good adsorbent and can adsorb the remaining trace thallium. A second flocculating agent can gather small suspended matters by high molecular adsorption, bridging and electric neutralization to form large flocculation, thereby improving the settling speed of the flocculation and the solid-liquid separation speed.

[0024] Compared with the prior art, the present application has at least the following advantages:

[0025] 1. The present application can treat high-chlorine and high-thallium wastewater by sequentially adding a thallium removal agent containing polysulfide, a multi-effect additive containing a first flocculating agent and manganese salt, and finally adding a second flocculating agent, so that thallium is almost completely precipitated from the solution; then, solid-liquid separation is performed on the solid-liquid mixture, thereby realizing deep purification and removal of thallium, and reducing the residue of the thallium removal agent.

[0026] 2. The present application has excellent thallium removal effect on thallium-containing wastewater with high thallium concentration; after treatment by precipitation, oxidation and flocculation, the thallium concentration can be reduced to below 5ug / L, meeting the Inorganic Chemical Industry Pollutant Discharge Standard (GB31573-2015) and realizing discharge in compliance with the standard.

[0027] 3. The present application is based on the deep thallium removal method for industrial wastewater by chemical precipitation, and when treating metallurgical wastewater containing a large amount of heavy metal ions, the removal effect on thallium is still excellent, and the reaction process is not affected by coexisting ions such as chloride ions. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present 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 are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the structures shown in the drawings.

[0029] Figure 1 XRD graph of thallium-containing precipitate in Example 1;

[0030] Figure 2 Curvilinear coordinate graph of thallium removal effect corresponding to different amounts of multi-effect additive in Analysis Example 1;

[0031] Figure 3 Raman graph of thallium-containing precipitate in Analysis Example 1.

[0032] The objectives, functional characteristics and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in conjunction with 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 of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the protection scope of the present application.

[0034] In addition, 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 of ordinary skill in the art can realize the combination. When the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0035] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified by the present application, both endpoints of each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all the technical and scientific terms used in the present application are consistent with the mastery of the prior art by the person of ordinary skill in the art and the description of the present application. 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 also be used to realize the present application.

[0036] In order to realize the deep purification of thallium in the wastewater containing chlorine and thallium, the present application provides a thallium removal method based on the wastewater containing chlorine and thallium, which comprises the following steps:

[0037] S1, providing the wastewater containing chlorine and thallium to be treated; the wastewater containing chlorine and thallium can include ash washing water, and specifically can be washing liquid obtained after the ash washing water of a sintering machine head in a metallurgical industry is washed; the wastewater containing chlorine and thallium contains chlorine elements and thallium elements, the concentration of the chlorine elements is 5-200 g / L, and the concentration of the thallium elements is 5 ug / L-20 mg / L; the thallium elements can include one or more of monovalent thallium and trivalent thallium, and specifically can include monovalent thallium, or include trivalent thallium, or include both monovalent thallium and trivalent thallium; in the ash washing water used in the present application, the thallium elements mainly exist in the form of monovalent thallium and contain part of trivalent thallium; the chlorine elements exist in the form of chloride ions.

[0038] It should be noted that, due to the technical advantages of the present application, the treatment of high-chlorine and high-thallium wastewater is also embodied, and the concentration of the chlorine elements can be 100-200 g / L; and / or, the concentration of the thallium elements can be 1-20 mg / L or 5-20 mg / L or 5-15 mg / L. The present application can realize the deep removal of thallium in a high-chlorine and high-thallium environment.

[0039] It should be noted that the chlorine-containing and thallium-containing wastewater can also contain Na element, K element, Ca element, Cu element, Si element, Zn element, Cd element, Mg element, Li element, Pb element, SO4 2- - In the chlorine-containing and thallium-containing wastewater, the concentration of Na element can be 38540±100mg / L, the concentration of K element can be 104260±100mg / L, the concentration of Ca element can be 2542.78±100mg / L, the concentration of Cu element can be 447.65±10mg / L, the concentration of Si element can be 357.54±10mg / L, the concentration of Zn element can be 328.3±10mg / L, the concentration of Cd element can be 109.9±10mg / L, the concentration of Mg element can be 29.64±5mg / L, the concentration of Li element can be 22.75±5mg / L, the concentration of Pb element can be 7.885±1mg / L, the concentration of SO4 2- - element can be 3190±100mg / L.

[0040] The pH of the chlorine-containing and thallium-containing wastewater to be controlled by the present application is greater than 11, and can be not less than 11.5 or not less than 12, such as 11.5-13 or 12-14. In order to control the pH of the chlorine-containing and thallium-containing wastewater, an acid or a base can be added to the chlorine-containing and thallium-containing wastewater; the acid can include nitric acid, and the base can include sodium hydroxide.

[0041] S2, mixing the chlorine-containing and thallium-containing wastewater with a thallium removal agent to obtain a first treatment liquid.

[0042] Mixing the chlorine-containing and thallium-containing wastewater with the thallium removal agent can be understood as follows: after the thallium removal agent is added to the chlorine-containing and thallium-containing wastewater, mixing is carried out for a certain period of time (the mixing time can be 5-8min or 5-10min).

[0043] The thallium removal agent includes a polysulfide, and the polysulfide can include calcium polysulfide; the calcium polysulfide used in the present application is CaS5, i.e. the S x 2- ​​In the embodiment, x is averagely 5. As an optional embodiment, the mass-volume ratio of the polysulfide and the wastewater containing chlorine and thallium can be no less than 4 g / L, and further can be 4-10 g / L or 5-10 g / L or 5-8 g / L. As another optional embodiment, the thallium removal agent can exist in a liquid form, and the volume percentage of the thallium removal agent and the wastewater containing chlorine and thallium can be 1-5% or 1.8-5% or 1.8-3%; the mass fraction of the polysulfide in the thallium removal agent can be 20-50% or 25-35%.

[0044] Although the final generated precipitate contains elemental sulfur, in order to ensure the progress of the reaction in the step, sodium sulfide and potassium sulfide can be added to reduce the precipitation of elemental sulfur in the polysulfide in the step. Therefore, the thallium removal agent can further include sodium sulfide and potassium sulfide, that is, the thallium removal agent is a sulfur compound thallium removal agent; the mass ratio of the polysulfide, the sodium sulfide and the potassium sulfide can be 50-1000:0.1-10:0.1-10, and further can be 100-300:0.5-1.5:0.5-1.5.

[0045] It should be noted that, in order to ensure that the manganese in the subsequent multi-effect additive generates manganese hydroxide with adsorbability, the pH of the first treatment liquid should be no less than 9, so as to ensure that the use effect of the multi-effect additive reaches the best; when the pH of the first treatment liquid is less than 9, the first treatment liquid can be adjusted to a pH no less than 9.

[0046] In the embodiment, the process of mixing the wastewater containing chlorine and thallium and the thallium removal agent can include: obtaining the thallium removal agent, and then mixing the thallium removal agent and the wastewater containing chlorine and thallium (the mixing time can be 5-8 min or 5-10 min), to obtain the first treatment liquid.

[0047] S3, mixing the first treatment liquid and a multi-effect additive to obtain a second treatment liquid; the multi-effect additive includes a first flocculant and a manganese salt.

[0048] Mixing the first treatment liquid and the multi-effect additive can be understood as: after the multi-effect additive is added to the first treatment liquid, a certain time of mixing (the mixing time can be 5-8 min or 5-10 min) is performed.

[0049] As an optional embodiment, the mass ratio of the first flocculant and the polysulfide can be 1:1-8, and further can be 1:1-6; the mass ratio of the first flocculant and the manganese salt can be 200:0.01-10, and further can be 200:0.5-5. As another optional embodiment, the multi-effect additive can exist in a liquid form; the volume ratio of the multi-effect additive and the thallium removal agent can be 0.05-5:1 or 0.3-0.8:1; the concentration of the first flocculant in the multi-effect additive can be 0.02-2 g / mL or 0.1-0.3 g / mL.

[0050] In the present application, the first flocculant can include one or more of polymeric aluminum ferric sulfate (PAFS or PFAS), polymeric aluminum ferric silicate (PSAF), polymeric aluminum silicate sulfate (PASS), polymeric ferric sulfate (PFS), and polymeric aluminum chloride (PAC). The manganese salt can include one or more of manganese sulfate, manganese chloride, and manganese nitrate.

[0051] In the present application, the process of mixing the first treatment liquid and the multi-effect additive includes: obtaining the multi-effect additive, and then mixing the multi-effect additive and the first treatment liquid (the mixing time can be 5-8 min or 5-10 min) to obtain the second treatment liquid.

[0052] S4, after mixing the second flocculant into the second treatment liquid, standing to obtain a third treatment liquid.

[0053] Mixing the second flocculant into the second treatment liquid can be understood as: after adding the second flocculant into the second treatment liquid, mixing for a short time (the mixing time can be 2-10 s); the standing time can be 2-10 min.

[0054] As an optional embodiment, the mass-volume ratio of the second flocculant and the chlorine-containing and thallium-containing wastewater can be 0.01-0.1 g / L, and further can be 0.01-0.05 g / L. As another optional embodiment, the second flocculant exists in a flocculation liquid; the volume percentage of the flocculation liquid and the chlorine-containing and thallium-containing wastewater can be 0.1-1% or 0.4-1% or 0.5-1%; the mass fraction of the second flocculant in the flocculation liquid can be 0.1-1% or 0.4-1% or 0.5-1%. The second flocculant can include one or more of anionic polyacrylamide, cationic polyacrylamide, and neutral polyacrylamide.

[0055] In the present application, the process of mixing the second flocculant into the second treatment liquid includes: obtaining a flocculation liquid containing the second flocculant, and then mixing the flocculation liquid and the second treatment liquid.

[0056] S5, solid-liquid separation treatment is conducted on the third treatment liquid to obtain a thallium-containing precipitate and a thallium-removing separation liquid.

[0057] It should be noted that, in the present application, by adding the thallium-removing agent, thallium ions form a hardly soluble compound; then by adding the multi-effect additive, a hydroxide adsorbent is generated to adsorb trace thallium, remove impurities of the thallium-removing agent which is not completely reacted, and condense the hardly soluble thallium precipitate; finally, by adding the flocculating agent, the flocculating precipitate and the hydroxide adsorbent are flocculated, so that the thallium in the chlorinated thallium-containing wastewater is deeply purified; and due to the generation of elemental sulfur, the influence of the thallium-removing agent is eliminated, and the residual sulfur ions are reduced; and the process of the present application is short and easy to operate.

[0058] The following is a specific example of the present application:

[0059] Example 1

[0060] The sintering machine electric field dust of a steel plant is measured to have a washing dust water with a pH of 9.6, a total thallium concentration of 9.58 mg / L in the washing dust water, and a chlorine concentration of 152140 mg / L, and the component content is shown in Table 1.

[0061] Table 1: Component of washing dust water

[0062] Element Content (mg / L) Element Content (mg / L) Na 38540 Cd 109.9 K 104260 Mg 29.64 Cl 152140 Li 22.75 Ca 2542.78 Tl 9.58 Cu 447.65 Pb 7.885 Si 357.54 SO4 2- ]]> 5610 Zn 328.3 NH4 - ]]> 3190

[0063] The washing dust water is treated by removing thallium, and the specific treatment process is as follows:

[0064] Step 1: 20 mL of washing dust water is taken, NaOH solid is added thereto, and stirring is conducted at a speed of 200 r / min to uniformly mix the washing dust water to adjust the pH of the washing dust water to 12.

[0065] Step 2: 600 mL of a calcium polysulfide solution with a mass fraction of 29%, 1 g of sodium sulfide, and 1 g of potassium sulfide are taken, the sodium sulfide and the potassium sulfide are dissolved in the calcium polysulfide solution, and after stirring to completely dissolve, a thallium-removing agent (denoted as a first additional liquid) is configured.

[0066] 0.4 mL of the first additional liquid is added to the washing dust water after the pH is adjusted, and then stirring is continuously conducted at a speed of 200 r / min for 5 min to obtain a first treatment liquid, and the pH of the first treatment liquid is 12.4.

[0067] Step 3: 20 g of polyferric sulfate (PFS) and 0.1 g of manganese sulfate are dissolved in 100 mL of pure water, and after stirring to completely dissolve, a multi-effect additive (denoted as a second additional liquid) is configured.

[0068] 0.2 mL of the second additional liquid is added to the first treatment liquid, and stirring is continuously conducted at a speed of 200 r / min for 5 min to obtain a second treatment liquid.

[0069] Step 4: Take the anionic polyacrylamide solution with a mass fraction of 0.5% (denoted as the third additional liquid).

[0070] Add 0.1 mL of the third additional liquid to the second treatment liquid, and stir at a speed of 250 r / min, stop stirring after 5 s, so that the precipitate is completely flocculated, and the precipitate is completely precipitated after standing for 5 min, to obtain a third treatment liquid containing the precipitate.

[0071] Step 5: Perform solid-liquid separation on the third treatment liquid, collect the thallium-containing precipitate and the thallium removal separation liquid, detect the concentration of thallium in the thallium removal separation liquid by an inductively coupled plasma mass spectrometer, and the results are shown in Table 2; analyze the thallium phase in the thallium-containing precipitate by XRD, and the results are shown in Table 2. Figure 1

[0072] Table 2: Thallium concentration before and after reaction and thallium removal rate

[0073]

[0074] The above results show that after about 15 min of treatment, the ash washing water concentration is reduced from 9.58 mg / L to 1.1 ug / L, which is lower than the emission limit of 5 ug / L in multiple industries and localities; XRD analysis shows that thallium mainly exists in the form of Tl2S in the precipitate.

[0075] Comparative Example 1

[0076] Compared with Example 1, the present comparative example does not add the corresponding thallium removal agent, and the remaining steps remain unchanged, only the multi-effect additive and the flocculant are added.

[0077] That is, compared with Example 1, the present comparative example omits Step 2, and the ash washing water after adjusting the pH in Step 1 is directly used as the first treatment liquid, and then Step 3 and the subsequent steps in Example 1 are performed, and the other conditions remain unchanged.

[0078] In the effluent of the present comparative example, the concentration of thallium is 5.91 mg / L, which is much higher than 5 ug / L, and cannot achieve the standard discharge, as shown in Table 3.

[0079] Table 3: Thallium concentration before and after reaction and thallium removal rate

[0080] Thallium content in washing water (mg / L) Thallium content in thallium removal separation liquid (mg / L) 9.58 5.91

[0081] Comparative Example 2

[0082] Compared with Example 1, the present comparative example does not add the corresponding multi-effect additive, and the remaining steps remain unchanged, only the thallium removal agent and the flocculant are added.

[0083] ​That is, compared with Example 1, this comparative example omits step 3, directly uses the first treatment liquid in step 2 as the second treatment liquid, and then performs step 4 and subsequent steps in Example 1, while keeping other conditions unchanged.

[0084] In the effluent of this comparative example, the concentration of thallium was 54 ug / L, which failed to meet the national emission standards, as shown in Table 4.

[0085] Table 4. Thallium concentration and thallium removal rate before and after the reaction.

[0086] Thallium content in washing water (mg / L) Thallium content in thallium removal separation liquid (mg / L) 9.58 0.054

[0087] Analysis Example 1

[0088] Compared to Example 1, the amount of the second added liquid in this analysis was adjusted to 0.12 mL, 0.16 mL, 0.20 mL, 0.24 mL, 0.28 mL, and 0.32 mL, respectively, while other conditions remained the same as in Example 1.

[0089] Under the above-mentioned amounts of the second added liquid, the volume ratio of the second added liquid to the first added liquid is 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, and 0.8:1, respectively.

[0090] In this analytical example, the experimental results are as follows: Figure 2 As shown (corresponding) Figure 2 (The proportion of additives on the horizontal axis); Raman analysis was used to analyze thallium-containing precipitates, such as... Figure 3 As shown.

[0091] The results show that both the second and first additive solutions in this analysis exhibit good thallium removal performance under the aforementioned ratios, with effluent concentrations lower than the emission limits of 5 μg / L for multiple industries and regions. Specifically, the volume ratios of the second and first additive solutions are 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, and 0.8:1, corresponding to thallium concentrations in the thallium-removed separation solutions of 2.97 μg / L, 2.83 μg / L, 1.89 μg / L, 2.74 μg / L, 1.53 μg / L, and 0.69 μg / L, respectively.

[0092] The volume ratio of the second added liquid to the first added liquid is 0.3:1 (corresponding to...). Figure 3 The ratios 1:0.3 and 0.5:1 (corresponding to...) Figure 3 The ratios 1:0.5 and 0.6:1 (corresponding to...) Figure 3 Taking the ratio of 1:0.6 as an example, Raman spectral analysis of thallium-containing precipitates revealed that: at ~152 cm⁻¹ -1 ~218cm -1 ~473cm -1The characteristic peak of elemental sulfur appeared, indicating that elemental sulfur was generated in the precipitate; thus, the precipitation of sulfur was achieved while ensuring the removal of thallium.

[0093] Analysis Example 2

[0094] In this analysis example, the amount of the first additional liquid was adjusted to 0.10 mL, 0.16 mL and 0.36 mL respectively compared with example 1; and the volume ratio of the second additional liquid to the first additional liquid was controlled to be 0.5:1 by adjusting the amount of the second additional liquid; and other conditions were the same as those in example 1.

[0095] In this analysis example, with the increase of the amount of the thallium removal agent (the first additional liquid), the effluent concentration of thallium ions gradually decreased; specifically, when the amount of the first additional liquid was 0.10 mL, 0.16 mL and 0.36 mL, the thallium concentration in the thallium removal and separation liquid was 647.8 μg / L, 208.73 μg / L and 4.7 μg / L respectively.

[0096] Analysis Example 3

[0097] In this analysis example, the amount of the first additional liquid was adjusted to 0.24 mL and the amount of the second additional liquid was adjusted to 0.12 mL compared with example 1; and the pH of the ash washing water was adjusted to 5, 7, 8, 9, 10, 11 and 12 respectively by using sodium hydroxide solid and dilute nitric acid; and the pH of the first treatment liquid was also adjusted to about 12; and other conditions were the same as those in example 1.

[0098] In this analysis example, the results showed that the pH had a significant effect on the removal of thallium. Specifically, when the pH of the ash washing water was adjusted to 5, 7, 8, 9, 10, 11 and 12, the thallium concentration in the thallium removal and separation liquid was 2357 μg / L, 2043 μg / L, 2402 μg / L, 2606 μg / L, 3518 μg / L, 2566 μg / L and 175 μg / L respectively.

[0099] In the above technical solution of the present application, the above is only a preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the content of the present application specification and drawings, 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 thallium from a wastewater containing thallium and thallium chloride, characterized by, The method comprises the steps of: S1, providing chlorinated and thallium-containing wastewater to be treated; S2, mixing the chlorinated and thallium-containing wastewater with a thallium removal agent to obtain a first treatment liquid; the thallium removal agent comprises a polysulfide; S3, mixing the first treatment liquid with a multi-effect auxiliary agent to obtain a second treatment liquid; the multi-effect auxiliary agent comprises a first flocculant and a manganese salt; S4, mixing a second flocculant into the second treatment liquid and standing to obtain a third treatment liquid; S5, performing solid-liquid separation treatment on the third treatment liquid to obtain thallium-containing precipitate and thallium removal separation liquid; The chlorinated thallium-containing wastewater contains Tl(I) and Tl(III), and also has Tl(III) and Cl - The complex [TlCl4 - ] formed; the polysulfide is disulfurized to generate sulfide ions and thiosulfate, the sulfide ions react with Tl(I) to generate Tl2S, and the thiosulfate reduces Tl(III) and its [TlCl4 - ] complex to Tl(I), and the Tl(I) reacts with the sulfide ions to generate Tl2S.

2. The method for removing thallium based on thallium and chlorine-containing wastewater according to claim 1, characterized in that, The pH of the chlorinated and thallium-containing wastewater is greater than 11.

3. The method for removing thallium based on thallium and chlorine-containing wastewater according to claim 1, characterized in that, The chlorinated and thallium-containing wastewater contains chlorine elements and thallium elements, the concentration of the chlorine elements is 5-200 g / L, and the concentration of the thallium elements is 5 ug / L-20 mg / L.

4. The method for removing thallium from wastewater containing thallium and thallium chloride according to claim 1, characterized by, The pH of the first treatment liquid is not less than 9.

5. The method for removing thallium from wastewater containing thallium and thallium chloride according to claim 1, wherein The mass-volume ratio of the polysulfide to the chlorinated and thallium-containing wastewater is 4-10 g / L.

6. The method for removing thallium from wastewater containing thallium and thallium chloride according to claim 1, wherein The thallium removal agent further comprises sodium sulfide and potassium sulfide; the mass ratio of the polysulfide, the sodium sulfide and the potassium sulfide is 50-1000:0.1-10:0.1-10; and the polysulfide comprises calcium polysulfide.

7. The method for removing thallium from wastewater containing thallium and thallium chloride according to claim 1, wherein The mass ratio of the first flocculant to the polysulfide is 1:1-8, and the mass ratio of the first flocculant to the manganese salt is 200:0.01-10.

8. The method for removing thallium from wastewater containing thallium and thallium chloride according to claim 1, wherein The first flocculant comprises one or more of polymeric aluminum ferric sulfate, polymeric aluminum ferric silicate, polymeric aluminum silicate sulfate, polymeric ferric sulfate and polymeric aluminum chloride.

9. The method for removing thallium from wastewater containing thallium and thallium chloride according to claim 1, wherein The manganese salt comprises one or more of manganese sulfate, manganese chloride and manganese nitrate.

10. The method for removing thallium from wastewater containing thallium and thallium chloride according to any one of claims 1 to 9, characterized by, The mass-volume ratio of the second flocculant to the chlorinated and thallium-containing wastewater is 0.01-0.1 g / L. The second flocculant comprises one or more of anionic polyacrylamide, cationic polyacrylamide and neutral polyacrylamide.

Images