Thallium removal method based on chlorine-containing thallium-containing wastewater

Abstract

The invention provides a thallium removal method based on waste water containing chlorine and thallium. The thallium removal method comprises the following steps: S1, providing waste water containing chlorine and thallium to be treated; s2, mixing the chlorine-containing thallium-containing wastewater with a thallium removal agent to obtain a first treatment solution; the thallium removal agent comprises polysulfide; s3, mixing the first treating fluid with a multi-effect additive to obtain a second treating fluid; 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; and S5, carrying out solid-liquid separation treatment on the third treatment liquid to obtain thallium-containing precipitate and thallium-removed separation liquid. According to the method, thallium in the chlorine-containing thallium-containing wastewater can be deeply purified, and introduction of new impurities can be reduced.

Description

Technical Field

[0001] The invention belongs to the field of wastewater treatment, and in particular relates to a method for removing thallium based on chlorine-containing and thallium-containing wastewater. Background Art

[0002] Thallium (Tl) is a typical toxic heavy metal with cumulative properties. It is one of the 13 metal pollutants recognized as priority control in the world. Thallium mainly causes toxic effects on the human nervous system, with a minimum lethal dose of 10-15 mg / kg. At the same time, thallium and thallium compounds are also mutagenic and carcinogenic and teratogenic. The toxic effect of thallium on the human body is much stronger than that of heavy metals such as lead, cadmium and mercury, and is close to the toxicity of arsenic. Thallium is often associated with metal sulfide ores such as iron, zinc, and lead. Industrial production processes such as steel smelting and non-ferrous metal smelting are accompanied by the production and discharge of a large amount of thallium. In order to strengthen the management and control of thallium, national policies, standards, and industry and local standards have further increased the requirements for thallium emission concentrations in recent years. The thallium emission standard for industrial wastewater in many industries and localities is 5μg / L.

[0003] Existing research on thallium removal technology focuses on the removal of thallium by adsorption in natural water bodies such as surface water and simulated water. However, the water quality conditions such as the presence form of thallium and thallium concentration are quite different from those in actual industrial wastewater, which makes it difficult for existing adsorbents to adapt to the characteristics of industrial wastewater with high fluorine and chlorine content and high thallium concentration. The commonly used method for thallium removal in industry is oxidation precipitation, because Tl usually exists in water bodies as Tl(I). Tl(I) is difficult to be adsorbed by conventional materials and does not generate precipitable hydroxides. It is more difficult to remove than Tl(III). Therefore, oxidants are usually added to oxidize the water-soluble Tl(I) into Tl(III). Tl(III) generates hydroxides under alkaline conditions and can be dehydrated to generate Tl2O3 precipitates. However, when the wastewater contains a large amount of chloride ions, after Tl(I) is oxidized, Tl(III) quickly reacts with Cl in the solution. - Combined to form a very stable complex [TlCl4 - ] and it is difficult to remove by precipitation, so the commonly used oxidation precipitation method is not suitable for wastewater with high chlorine and high thallium. The sulfide precipitation method forms Tl2S precipitation by adding sulfide. Limited by the solubility product, the theoretical maximum thallium concentration in the wastewater is reduced to about 45μg / L. The existing adsorbents of the adsorption method are greatly affected by coexisting ions. Therefore, the above methods are difficult to meet the increasingly stringent emission requirements, and it is urgent to develop new thallium removal technologies.

[0004] The Chinese patent application with publication number CN115947436A records a method for removing thallium from lead and zinc smelting wastewater, which prepares a thallium removal agent based on mercapto, hydroxyl and carboxyl coordination groups and adds the thallium removal agent to the smelting wastewater to reduce the thallium concentration in the smelting wastewater, thereby achieving standard discharge. The Chinese patent application with publication number CN105254075A records a heavy metal scavenger and a thallium removal method for sintering desulfurization wastewater, which removes thallium from the desulfurization wastewater by coagulation, adding a scavenger, and flocculation. Although the above patent application achieves the removal of thallium; however, the initial thallium concentration of the above patent application is low, and it does not treat thallium with a higher concentration; and the above patent application does not achieve deep removal of thallium in the presence of a large amount of chloride ions and thallium ions.

[0005] In view of this, it is necessary to provide a thallium removal method based on chlorine-containing and thallium-containing wastewater to solve or at least alleviate the technical defect of how to deeply remove thallium when the thallium ion concentration is high and a large amount of chloride ions coexist. Summary of the invention

[0006] The main purpose of the present invention is to provide a thallium removal method based on chlorine-containing and thallium-containing wastewater, aiming to solve or at least alleviate the technical problem of how to deeply remove thallium when the thallium ion concentration is high and a large amount of chloride ions coexist.

[0007] To achieve the above object, the present invention provides a method for removing thallium from chlorine-containing and thallium-containing wastewater, comprising the steps of:

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

[0009] S2, mixing the chlorine-containing and thallium-containing wastewater with a thallium-removing agent to obtain a first treated liquid; the thallium-removing agent includes polysulfide;

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

[0011] S4, mixing the second flocculant into the second treated liquid and letting it stand to obtain a third treated liquid;

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

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

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

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

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

[0017] Furthermore, the thallium removal agent also includes 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 includes calcium polysulfide.

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

[0019] Furthermore, the first flocculant includes one or more of polyaluminium ferric sulfate, polyaluminium ferric silicate, polyaluminium silicate sulfate, polyferric sulfate and polyaluminium chloride.

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

[0021] Furthermore, the mass volume ratio of the second flocculant to the chlorine-containing and thallium-containing wastewater is 0.01 to 0.1 g / L;

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

[0023] The main technical principle of the present invention includes: when oxidizing and removing thallium, Tl(III) formed in high-chlorine wastewater easily reacts with Cl in the solution. - Combine to form a stable complex [TlCl4 - ] and is difficult to remove by precipitation. In the present invention, polysulfide (S x 2- , x = 2-7, the average is 5) will undergo a disproportionation reaction to generate sulfide ions (S 2- ) and thiosulfate (S2O3 2- )(S5 2- +3OH - →S2O3 2- +3HS - ); the present invention first adds polysulfide, sulfide ion (S 2- ) reacts with Tl(I) to form Tl2S which is insoluble in water, and thiosulfate (S2O3 2- ) has strong reducing properties and can convert Tl(III) and its [TlCl4 - ] complex is reduced to Tl(I), avoiding Cl - The Tl(I) produced by reduction further reacts with sulfide ions (S 2-) reacts to generate Tl2S which is insoluble in water, thus achieving the preliminary precipitation and removal of thallium. Then, a multi-effect additive is added. The first flocculant in the multi-effect additive can generate hydroxide through chemical reaction. This hydroxide can adsorb suspended matter in water by neutralizing positively charged colloidal particles and surfactants to form flocculation and precipitation; Mn(OH)2 generated by manganese ions under alkaline conditions is a good adsorbent that can adsorb the remaining trace thallium. The second flocculant can aggregate small suspended matter through polymer adsorption, bridging and electrical neutralization to form large floccules, increase the sedimentation rate of floccules, and increase the solid-liquid separation rate.

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

[0025] 1. The present invention can treat wastewater with high chlorine and high thallium content by sequentially adding a thallium removal agent containing polysulfide, a multi-effect auxiliary agent containing a first flocculant and a manganese salt, and finally adding a second flocculant, so that thallium is almost completely precipitated from the solution; thereafter, the solid-liquid mixture is subjected to solid-liquid separation, so that deep purification and removal of thallium can be achieved, and the residue of the thallium removal agent can be reduced.

[0026] 2. The present invention has an excellent thallium removal effect on thallium-containing wastewater with a high thallium concentration; after treatment by precipitation, oxidation, flocculation, etc., the thallium concentration can be reduced to below 5ug / L, meeting the "Inorganic Chemical Industry Pollutant Emission Standard" (GB31573-2015), and achieving standard emissions.

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

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 is the XRD pattern of the thallium-containing precipitate in Example 1;

[0030] Figure 2 It is a curve coordinate diagram of the thallium removal effect corresponding to different multi-effect auxiliary agent dosages in Analysis Example 1;

[0031] Figure 3 This is the Raman diagram of the thallium-containing precipitate in Analysis Example 1.

[0032] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are familiar to those skilled in the art and the description of the present invention, and any methods, equipment and materials of the prior art similar or equivalent to the methods, equipment and materials described in the embodiments of the present invention can also be used to implement the present invention.

[0036] In order to achieve deep purification of thallium in chlorine-containing and thallium-containing wastewater, the present invention provides a thallium removal method based on chlorine-containing and thallium-containing wastewater, comprising the steps of:

[0037] S1, providing chlorine-containing and thallium-containing wastewater to be treated; the chlorine-containing and thallium-containing wastewater may include ash washing water, specifically washing liquid taken from ash washing of sintering machine heads in the metallurgical industry; the chlorine-containing and thallium-containing wastewater contains chlorine and thallium, the concentration of the chlorine is 5-200g / L, and the concentration of the thallium is 5ug / L-20mg / L; the thallium element may include one or more of monovalent thallium and trivalent thallium, specifically may include monovalent thallium, or include trivalent thallium, or include monovalent thallium and trivalent thallium at the same time; in the ash washing water used in the present invention, the thallium element is mainly in the form of monovalent thallium, containing part of trivalent thallium; the chlorine element exists in the form of chloride ions.

[0038] It should be noted that, since the technical advantage of the present invention is also reflected in the treatment of high-chlorine and high-thallium wastewater, the concentration of the chlorine element can be 100-200 g / L; and / or, the concentration of the thallium element can be 1-20 mg / L or 5-20 mg / L or 5-15 mg / L. The present invention can achieve deep removal of thallium in a high-chlorine and high-thallium environment.

[0039] It should also be noted that the chlorine-containing and thallium-containing wastewater may also contain Na, K, Ca, Cu, Si, Zn, Cd, Mg, Li, Pb, SO4 2- NH4 - ; 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, SO4 2- The concentration of the element can be 5610±100mg / L, NH4 - The concentration of the element can be 3190±100 mg / L.

[0040] The present invention needs to control the pH of the chlorine-containing thallium-containing wastewater to be greater than 11, and further can be not less than 11.5 or not less than 12, such as 11.5 to 13 or 12 to 14. In order to control the pH of the chlorine-containing thallium-containing wastewater, an acid or a base can be added to the chlorine-containing 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-removing agent to obtain a first treated liquid.

[0042] Mixing the chlorine-containing and thallium-containing wastewater and the thallium-removing agent can be understood as: adding the thallium-removing agent into the chlorine-containing and thallium-containing wastewater, and then mixing for a certain period of time (the mixing time can be 5 to 8 minutes or 5 to 10 minutes).

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

[0044] Although the final precipitate generated in the present invention contains elemental sulfur, in order to ensure the progress of the reaction in this step, sodium sulfide and potassium sulfide can be added in this step to reduce the precipitation of elemental sulfur in the polysulfide. Therefore, the thallium removal agent may also include sodium sulfide and potassium sulfide, that is, the thallium removal agent is a sulfur-compounded thallium removal agent; the mass ratio of the polysulfide, the sodium sulfide and the potassium sulfide may be 50-1000:0.1-10:0.1-10, and may further 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 adsorptive manganese hydroxide, the pH of the first treatment liquid must be no less than 9 to ensure that the use effect of the multi-effect additive is optimal; when the pH of the first treatment liquid is less than 9, the first treatment liquid can be adjusted to a pH of no less than 9.

[0046] In the present invention, the process of mixing the chlorine-containing and thallium-containing wastewater with the thallium-removing agent may include: obtaining the thallium-removing agent, and then mixing the thallium-removing agent with the chlorine-containing and thallium-containing wastewater (the mixing time may be 5 to 8 minutes or 5 to 10 minutes) to obtain the first treatment liquid.

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

[0048] Mixing the first treatment liquid and the multi-effect aid can be understood as: adding the multi-effect aid to the first treatment liquid, and then mixing for a certain period of time (the mixing time may be 5 to 8 minutes or 5 to 10 minutes).

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

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

[0051] In the present invention, the process of mixing the first treatment liquid and the multi-effect aid comprises: obtaining the multi-effect aid, and then mixing the multi-effect aid and the first treatment liquid (mixing time may be 5 to 8 minutes or 5 to 10 minutes) to obtain the second treatment liquid.

[0052] S4, mixing the second flocculant into the second treated liquid and letting it stand to obtain a third treated 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, briefly mixing (mixing time may be 2 to 10 seconds); the standing time may be 2 to 10 minutes).

[0054] As an optional embodiment, the mass volume ratio of the second flocculant to the chlorine-containing 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 is present in the flocculation liquid; the volume percentage of the flocculation liquid and the chlorine-containing 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 invention, the process of mixing the second flocculant into the second treatment liquid includes: obtaining a flocculant liquid containing the second flocculant, and then mixing the flocculant liquid and the second treatment liquid.

[0056] S5, performing solid-liquid separation treatment on the third treatment liquid to obtain thallium-containing precipitate and thallium-removed separation liquid.

[0057] It should be pointed out that, in the present invention, by adding the thallium removal agent, thallium ions are formed into insoluble compounds; then the multi-effect auxiliary agent is added to generate a hydroxide adsorbent and adsorb trace thallium, oxidize the unreacted thallium removal agent to remove impurities, and condense insoluble thallium precipitates; finally, a flocculant is added to flocculate the precipitate and the hydroxide adsorbent, thereby achieving deep purification of thallium in chlorine-containing and thallium-containing wastewater; and, due to the generation of elemental sulfur, the present invention also eliminates the influence of the thallium removal agent and reduces the residual sulfur ions; and the process of the present invention is short and the operation is simple.

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

[0059] Example 1

[0060] The pH of the ash washing water from the sintering machine field of a steel plant was measured to be 9.6, the total thallium concentration in the ash washing water was 9.58 mg / L, and the chlorine concentration was 152140 mg / L. The composition contents are shown in Table 1.

[0061] Table 1 Ash washing water composition

[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 <![CDATA[SO4 2- ]]> 5610 Zn 328.3 <![CDATA[NH4 - ]]> 3190

[0063] The above-mentioned ash washing water is treated to remove thallium. The specific treatment process is as follows:

[0064] Step 1: Take 20 mL of ash washing water, add solid NaOH to it, and stir at 200 r / min to adjust the pH of the ash washing water to 12.

[0065] Step 2: Take 600 mL of 29% calcium polysulfide solution, 1 g of sodium sulfide, and 1 g of potassium sulfide, dissolve the sodium sulfide and potassium sulfide in the calcium polysulfide solution, stir until completely dissolved to prepare a thallium removal agent (recorded as the first added liquid).

[0066] 0.4 mL of the first additional liquid was added to the pH-adjusted lime washing water, and then the mixture was stirred at a speed of 200 r / min for 5 min to obtain a first treated liquid, the pH of which was 12.4.

[0067] Step 3: Take 20 g of polyferric sulfate (PFS) and 0.1 g of manganese sulfate and dissolve them in 100 mL of pure water. Stir until completely dissolved to prepare a multi-effect additive (recorded as the second additional liquid).

[0068] 0.2 mL of the second additional liquid was added to the first treated liquid, and the mixture was stirred at a speed of 200 r / min for 5 min to obtain a second treated liquid.

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

[0070] 0.1 mL of the third additional liquid was added to the second treatment liquid, and the mixture was stirred at a speed of 250 r / min. The stirring was stopped after 5 seconds to allow the precipitate to completely flocculate. The precipitation was complete after standing for 5 minutes, thereby obtaining a third treatment liquid containing a precipitate.

[0071] Step 5: The third treatment liquid is subjected to solid-liquid separation, and the thallium-containing precipitate and the thallium-removing separation liquid are collected. The concentration of thallium in the thallium-removing separation liquid is detected by inductively coupled plasma mass spectrometry, and the results are shown in Table 2; the thallium phase in the thallium-containing precipitate is analyzed by XRD, as shown in Table 2. Figure 1 shown.

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

[0073]

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

[0075] Comparative Example 1

[0076] Compared with Example 1, the corresponding thallium removal agent is not added in this comparative example, and the other steps remain unchanged, and only the multi-effect auxiliary agent and the flocculant are added.

[0077] That is, compared with Example 1, step 2 is omitted in this comparative example, the lime washing water after pH adjustment in step 1 is directly used as the first treatment liquid, and then step 3 and subsequent steps in Example 1 are performed, and other conditions remain unchanged.

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

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

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

[0081] Comparative Example 2

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

[0083] That is, compared with Example 1, step 3 is omitted in this comparative example, the first treatment liquid in step 2 is directly used as the second treatment liquid, and then step 4 and subsequent steps in Example 1 are performed, and other conditions remain unchanged.

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

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

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

[0087] Analysis example 1

[0088] Compared with Example 1, the amount of the second additional liquid in this analysis example was adjusted to 0.12 mL, 0.16 mL, 0.20 mL, 0.24 mL, 0.28 mL, and 0.32 mL, respectively. Other conditions were the same as in Example 1.

[0089] Under the above-mentioned dosages of the second additional liquid, the volume ratios of the second additional liquid to the first additional liquid are 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, and 0.8:1, respectively.

[0090] In this analysis example, the test results are as follows Figure 2 As shown (corresponding to Figure 2 The additive ratio in the horizontal axis); Raman analysis of thallium-containing precipitates, such as Figure 3 shown.

[0091] The results show that the second added liquid and the first added liquid in this analysis example have good thallium removal effects under the above-mentioned ratios, and the effluent concentration is lower than the emission limit of 5μg / L in many industries and places; specifically, the volume ratios of the second added liquid and the first added liquid are 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, and 0.8:1, and the corresponding thallium concentrations in the thallium removal separation liquid are 2.97μg / L, 2.83μg / L, 1.89μg / L, 2.74μg / L, 1.53μg / L, and 0.69μg / L, respectively.

[0092] The volume ratio of the second additional liquid to the first additional liquid is 0.3:1 (corresponding to Figure 3 1:0.3), 0.5:1 (corresponding to Figure 3 1:0.5), 0.6:1 (corresponding to Figure 3 As an example, the Raman spectrum analysis of the thallium-containing precipitate found that: at ~152cm -1 、~218cm -1 、~473cm -1The characteristic peak of elemental sulfur appeared at , indicating that elemental sulfur was generated in the precipitate; therefore, while ensuring the removal of thallium, this analysis example also achieved the precipitation of sulfur.

[0093] Analysis example 2

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

[0095] In this analysis example, as the amount of thallium removal agent (first additional liquid) increases, the effluent concentration of thallium ions gradually decreases; specifically, the amount of the first additional liquid is 0.10mL, 0.16mL, and 0.36mL, and the corresponding thallium concentrations in the thallium removal separation liquid are 647.8μg / L, 208.73μg / L, and 4.7μg / L, respectively.

[0096] Analysis example 3

[0097] Compared with Example 1, the amount of the first additional liquid in this analysis example is adjusted to 0.24 mL, and the amount of the second additional liquid is adjusted to 0.12 mL; solid sodium hydroxide and dilute nitric acid are used to adjust the pH of the ash washing water to 5, 7, 8, 9, 10, 11, and 12, respectively; the pH of the first treatment liquid is also adjusted to about 12; other conditions are the same as in Example 1.

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

[0099] The above technical solutions of the present invention are only preferred embodiments of the present invention, and the patent scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for removing thallium from chlorine-containing and thallium-containing wastewater, It is characterized in that Includes steps: S1, providing chlorine-containing and thallium-containing wastewater to be treated; S2, mixing the chlorine-containing and thallium-containing wastewater with a thallium-removing agent to obtain a first treated liquid; the thallium-removing agent includes polysulfide; S3, mixing the first treatment liquid and a multi-effect auxiliary agent to obtain a second treatment liquid; the multi-effect auxiliary agent includes a first flocculant and a manganese salt; S4, mixing the second flocculant into the second treated liquid and letting it stand to obtain a third treated liquid; S5, performing solid-liquid separation treatment on the third treatment liquid to obtain thallium-containing precipitate and thallium-removed separation liquid.

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

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

4. The thallium removal method based on chlorine-containing and thallium-containing wastewater according to claim 1, It is characterized in that The pH of the first treatment liquid is not less than 9.

5. The thallium removal method based on chlorine-containing and thallium-containing wastewater according to claim 1, It is characterized in that The mass volume ratio of the polysulfide to the chlorine-containing and thallium-containing wastewater is 4 to 10 g / L.

6. The thallium removal method based on chlorine-containing and thallium-containing wastewater according to claim 1, It is characterized in that The thallium removal agent also includes 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 includes calcium polysulfide.

7. The thallium removal method based on chlorine-containing and thallium-containing wastewater according to claim 1, It is characterized in that The mass ratio of the first flocculant to the polysulfide is 1:1-8; the mass ratio of the first flocculant to the manganese salt is 200:0.01-10.

8. The thallium removal method based on chlorine-containing and thallium-containing wastewater according to claim 1, It is characterized in that The first flocculant includes one or more of polyaluminium ferric sulfate, polyaluminium ferric silicate, polyaluminium silicate sulfate, polyferric sulfate and polyaluminium chloride.

9. The method for removing thallium from chlorine-containing and thallium-containing wastewater according to claim 1, It is characterized in that The manganese salt includes one or more of manganese sulfate, manganese chloride and manganese nitrate.

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

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