Method for treating acidic high-salt tungsten slag wastewater and recycling heavy metals and organic matters

Abstract

The invention provides a method for treating acidic high-salt tungsten slag wastewater and recycling heavy metals and organic matters. The method comprises four steps of precipitation, primary adsorption, secondary adsorption and oxidative deamination. The method comprises the following steps: firstly, adding ammonium oxalate into the tungsten slag wastewater to obtain intermediate effluent I and ferric oxalate precipitate; enabling the intermediate effluent I to flow through a silver-copper exchange resin column, and removing silver and copper in the wastewater to obtain intermediate effluent II; then, after the second intermediate effluent flows through an organic matter exchange resin column, organic matters in the wastewater are removed, and third intermediate effluent is obtained; finally, alkali is added into the third intermediate effluent to adjust the pH value to be alkaline, then an ammonia nitrogen remover is added, aeration reaction is carried out, a PAM coagulant aid is added after the reaction is completed, standing and sedimentation are carried out, sludge and final effluent are obtained, and ammonia nitrogen in the wastewater is effectively removed. According to the method, pollutants such as heavy metal, ammonia nitrogen and COD in the acidic high-salt tungsten slag wastewater are effectively removed through a physical method, recycling of iron, silver, copper and the like and the organic extraction agent is achieved, resources are saved, and the environment is protected.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, in particular to a method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter. Background Art

[0002] Tungsten slag wastewater is the production wastewater produced by re-smelting the slag produced after smelting tungsten ore to further extract the useful metals therein. Tungsten slag smelting generally adopts pretreatment, acid hydrolysis, silver extraction, tungsten extraction, scandium extraction, iron and manganese extraction and other treatment processes to recover tungsten and other useful metals. The generated wastewater still contains a relatively high concentration of various useful metals and other substances, mainly including calcium, iron, silver, copper, nickel, manganese, extractant organic matter, etc. The metal substances contained therein still have important recovery value. The extractant contained therein is the agent needed to be used in the tungsten slag smelting process, which can be recycled and reused. The direct discharge of tungsten slag production wastewater will inevitably pollute the ecological environment and do not meet the emission requirements. Therefore, the tungsten slag wastewater is treated to extract and recover the heavy metals and extractant organic matter therein, which can not only realize resource recovery, but also realize the effective treatment of wastewater, and has important economic value and environmental value.

[0003] Tungsten slag wastewater is a strongly acidic wastewater that contains high salt and ammonia nitrogen. It is difficult to treat directly through conventional biological methods. This method optimizes the design based on the characteristics of various substances in the wastewater and proposes a tungsten slag wastewater treatment method that is both innovative and scientific, providing a new idea for the treatment of tungsten slag wastewater. Summary of the invention

[0004] The purpose of the present invention is to provide a method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter, so as to solve the technical problem that the direct discharge of existing tungsten slag production wastewater will inevitably pollute the ecological environment and fail to meet the discharge requirements. The method of the present invention treats tungsten slag wastewater, extracts and recovers heavy metals and extractant organic matter therein, which can achieve resource recovery and effective wastewater treatment.

[0005] To achieve the above object, the present invention provides a method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter, comprising the following steps:

[0006] S1: Add ammonium oxalate to the tungsten slag wastewater, stir to react, and let it stand to precipitate, to obtain intermediate water and iron oxalate precipitate;

[0007] S2: passing the intermediate effluent 1 obtained in step S1 through a silver-copper exchange resin column to remove silver and copper in the wastewater to obtain intermediate effluent 2;

[0008] S3: passing the intermediate effluent II obtained in step S2 through an organic exchange resin column to remove organic matter in the wastewater, thereby obtaining intermediate effluent III;

[0009] S4: firstly add alkali to the intermediate effluent obtained in step S3 to adjust the pH value, then add an ammonia nitrogen remover, introduce air for aeration and mixing reaction to remove the ammonia nitrogen in the wastewater; after the reaction is completed, add a coagulant, slowly stir evenly, and then let it stand to precipitate to obtain the final effluent and sludge.

[0010] Furthermore, in step S1, the mass ratio of the ammonium oxalate to the iron in the tungsten slag wastewater is 3-4:1, the stirring reaction time is 0.5-1.0 h, and the static precipitation time is 0.5-2.0 h.

[0011] Furthermore, in step S2, the silver-copper exchange resin column is filled with a gel-type strongly acidic cation exchange resin, the total exchange capacity is 1.0 to 3.0 mmol / mL wet resin, the wet true density is 1.05 to 1.15 g / mL, the height-to-diameter ratio of the silver-copper exchange resin column is 3 to 6:1, and the operating flow rate is 2 to 10 BV / h.

[0012] Furthermore, after step S2, step S5 is also included: after the silver-copper exchange resin column is saturated with adsorption, a silver-copper desorbent is injected into the silver-copper exchange resin column to regenerate the silver-copper exchange resin, the silver and copper ions adsorbed by the silver-copper exchange resin are transferred to the silver-copper desorption liquid for discharge, and the silver-copper exchange resin is regenerated and reused; elemental copper powder is added to the silver-copper desorption liquid, stirred for reaction, to obtain elemental silver and copper-containing desorption liquid, and then the copper-containing desorption liquid is electrolyzed to obtain elemental copper;

[0013] Furthermore, in step S5, the silver-copper desorbent is one or more of nitric acid, sulfuric acid, hydrofluoric acid and hydrochloric acid, with a concentration of 4% to 15%; and the regeneration flow rate of the silver-copper exchange resin column is 1 to 4 BV / h.

[0014] Furthermore, in step S3, the organic exchange resin column is filled with a cross-linked polystyrene macroporous adsorption resin with a specific surface area of ​​200 to 1200 m2 / g, a porosity of 20% to 50%, an average pore size of 10 to 50 nm, a wet true density of 1.05 to 1.15 g / mL, a height-to-diameter ratio of 3 to 6:1, and an operating flow rate of 2 to 10 BV / h.

[0015] Furthermore, after step S3, step S6 is also included: after the organic exchange resin column is saturated with adsorption, an organic desorbent is injected into the organic exchange resin column to regenerate the organic exchange resin, and the regeneration flow rate is 1 to 4 BV / h; the organic matter adsorbed by the organic exchange resin is transferred to a desorption liquid containing organic matter for discharge, and the organic exchange resin column is reused after regeneration; the organic desorption liquid is heated for distillation, and the organic desorbent is separated in the form of gas, which is collected and reused for the regeneration of the organic exchange resin, and the generated organic matter is recycled.

[0016] Furthermore, in step S6, the organic desorbent is methanol, and the distillation temperature is 70°C.

[0017] Further, in step S4, the ammonia nitrogen remover is a powder uniformly mixed with 10% to 40% adsorbent, 30% to 60% oxidant, and 20% to 45% coagulant, and the dosage is 1 to 10 g / L. The adsorbent is one or more of struvite, diatomaceous earth, molecular sieve, activated carbon, activated alumina, and zeolite. The coagulant is one or more of polyaluminum chloride, aluminum sulfate, ferric sulfate, ferric chloride, polyferric sulfate, and polyacrylamide. The oxidant is one or more of bleaching powder, sodium hypochlorite, calcium hypochlorite, potassium permanganate, potassium perchlorate, potassium perchlorate, potassium ferrate, sodium persulfate, and benzoyl peroxide. The aeration mixing reaction time is 1.0 to 4.0 h, and the static sedimentation time is 0.5 to 2.0 h.

[0018] Furthermore, in step S4, the alkali is one or more of sodium hydroxide, ammonia water, and lime, and the pH value is adjusted in the range of 9.0 to 12.0; the coagulant aid is polyacrylamide, and the dosage is 1 to 20 mg / L.

[0019] The present invention has the following beneficial effects:

[0020] 1. The method of the present invention realizes the recovery of iron, silver, copper and organic matter in tungsten slag production wastewater by connecting multiple stages in series, and at the same time realizes the effective treatment of wastewater.

[0021] 2. Tungsten slag production wastewater is an acidic high-salt wastewater, which is difficult to treat by conventional biological treatment methods. The method of the present invention combines physical and chemical methods to achieve simple and effective treatment of wastewater. The process does not require pH adjustment in the early stage to achieve the treatment and recovery of heavy metals and organic matter. The process flow is simple and cost-saving.

[0022] 3. The method of the present invention uses an ammonia nitrogen remover to remove ammonia nitrogen in wastewater through oxidative deamination. Compared with the biological ammonia oxidation method, it is suitable for high-salt wastewater treatment, reduces sludge production, and saves electricity.

[0023] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 This is an overall process flow chart of a method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to the present invention;

[0026] Figure 2 is a flow chart of step S1 in the present invention;

[0027] Figure 3 is a flow chart of step S4 in the present invention;

[0028] Figure 4 is a flow chart of step S5 in the present invention;

[0029] Figure 5 is a flow chart of step S6 in the present invention;

[0030] Among them, S1 is precipitation method; S2 is primary adsorption; S3 is secondary adsorption; S4 is oxidative deamination; S5 is silver-copper exchange resin regeneration; S6 is organic exchange resin regeneration. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, but the present invention can be implemented in a variety of different ways as defined and covered by the claims. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in the art or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0032] Tungsten slag is a by-product produced in the process of smelting tungsten ore. The discarded tungsten slag after smelting still contains a large amount of useful metals such as tungsten, copper, nickel, silver, manganese, iron, scandium, calcium, etc., and has recycling value. After recycling, it can also reduce the amount of waste, reduce secondary pollution of solid waste and environmental pollution problems such as heavy metals. The typical tungsten slag smelting process uses "acid leaching → filter press → iron powder replacement of silver → N235 extraction of tungsten → P204+TBP extraction of scandium → precipitation of ferromanganese → extraction of calcium chloride" to extract metal substances, which produces production wastewater. The wastewater is acidic, high in salinity, and contains useful metal substances such as iron, manganese, silver, copper, nickel, and calcium, as well as ammonia nitrogen and extractant organic matter. The pH is generally between 1 and 3, the salinity is 15% to 18%, and the iron content is 15,000 to 20,000 mg / L, the silver content is 10 to 50 mg / L, the copper content is 500 to 800 mg / L, the ammonia nitrogen content is 800 to 1000 mg / L, and the TOC content is 600 to 1000 mg / L.

[0033] Tungsten slag wastewater is a kind of difficult-to-biochemically treat process wastewater with high salinity, poor biodegradability and high heavy metal content. It is difficult to treat it through ordinary biochemical treatment processes. At the same time, the wastewater has the value of recovering heavy metals. The present invention provides a tungsten slag wastewater treatment method, which combines physical and chemical methods. First, precipitation is used to remove iron from the wastewater, and then a multi-stage ion exchange method is used to remove silver, copper and other heavy metals with recovery value and extractant organic matter in the wastewater, and then the wastewater is regenerated by resin, and then the ammonia nitrogen in the wastewater is removed by oxidative deamination. The treatment of tungsten slag wastewater by the method of the present invention can not only achieve effective treatment of wastewater, but also realize resource recovery of substances such as heavy metals and organic matter, providing a new idea for the treatment of tungsten slag wastewater.

[0034] like Figures 1 to 5 As shown, a method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter comprises four steps, namely, precipitation method S1, primary adsorption S2, secondary adsorption S3 and oxidative deamination S4, as follows:

[0035] S1 precipitation method: add ammonium oxalate to the tungsten slag wastewater, stir to react, and after the reaction is completed, let it stand and precipitate to obtain intermediate water and iron oxalate precipitate, which is discharged and recovered to achieve the removal and recovery of iron in the wastewater;

[0036] The reaction equation between iron ion Fe(III) and ammonium oxalate in tungsten slag wastewater is as follows:

[0037] 2Fe 3+ +3(NH4)2C2O4→6NH4 + +Fe2(C2O4)3(s)

[0038] Ferric oxalate is insoluble in water and decomposes when heated to 100°C. Ferric oxalate can be used directly or further processed to obtain elemental iron.

[0039] S2 primary adsorption: Intermediate effluent 1 undergoes primary adsorption, and after passing through the silver-copper exchange resin column, the silver and copper in the wastewater are adsorbed onto the silver-copper exchange resin column through ion exchange and removed to obtain intermediate effluent 2. After the silver-copper exchange resin column is saturated with adsorption, the S5 silver-copper exchange resin column is regenerated.

[0040] S3 secondary adsorption: the intermediate effluent 2 undergoes secondary adsorption, and after passing through the organic exchange resin column, the organic matter in the wastewater is adsorbed onto the organic exchange resin column and removed to obtain intermediate effluent 3; after the organic exchange resin column is saturated with adsorption, the S6 organic exchange resin column is regenerated.

[0041] S4 oxidative deammoniation: first add alkali to the intermediate effluent three to adjust the pH value, then add ammonia nitrogen remover, introduce air for aeration and mixing reaction to remove ammonia nitrogen in the wastewater. After the reaction is completed, add a certain amount of polyacrylamide, slowly stir evenly, strengthen coagulation, and then let it stand and settle to obtain the final effluent and sludge.

[0042] S5 Regeneration of silver-copper exchange resin: After the silver-copper exchange resin column is saturated with adsorption, a silver-copper desorbent is injected into the silver-copper exchange resin column to regenerate the silver-copper exchange resin, and the silver and copper ions adsorbed by the silver-copper exchange resin are transferred to the silver-copper desorption liquid and discharged, and the silver-copper exchange resin is reused after regeneration; elemental copper powder is added to the silver-copper desorption liquid, and the reaction is stirred to cause a substitution reaction. After the silver ions are replaced, elemental silver and copper-containing desorption liquid are obtained, and the copper-containing desorption liquid is electrolyzed to obtain elemental copper, and the elemental copper is recovered; the silver-copper desorbent uses one or more of nitric acid, sulfuric acid, hydrofluoric acid and hydrochloric acid, and the concentration is 4% to 15%; the regeneration flow rate of the silver-copper exchange resin column is 1 to 4BV / h.

[0043] The reaction of copper replacing silver is as follows:

[0044] Cu(s)+Ag + →Cu 2+ +Ag(s)

[0045] S6 Regeneration of organic exchange resin: After the organic exchange resin column is saturated with adsorption, an organic desorbent is injected into the organic exchange resin column to regenerate the organic exchange resin. The regeneration flow rate is 1 to 4 BV / h. The organic matter adsorbed by the organic exchange resin is transferred to the desorption liquid containing organic matter and discharged. The organic exchange resin is reused after regeneration; the organic desorption liquid is heated to a certain temperature for distillation, and the organic desorbent is separated in the form of gas, which is collected and reused for the regeneration of the organic exchange resin. The generated organic matter is recycled. Methanol is used as the organic desorbent, and the distillation temperature is 70°C.

[0046] Furthermore, in the step S1, the mass ratio of ammonium oxalate to iron in the tungsten slag wastewater is 3-4:1, the stirring reaction time is 0.5-1.0h, and the static precipitation time is 0.5-2.0h.

[0047] Furthermore, in step S2, the silver-copper exchange resin column is filled with a gel-type strongly acidic cation exchange resin, the total exchange capacity is 1.0 to 3.0 mmol / mL of wet resin, the wet true density is 1.05 to 1.15 g / mL, the height-to-diameter ratio of the silver-copper exchange resin column is 3 to 6:1, and the operating flow rate is 2 to 10 BV / h.

[0048] Furthermore, in step S3, the organic exchange resin column is filled with a cross-linked polystyrene macroporous adsorption resin having a specific surface area of ​​200 to 1200 m 2 / g, a pore size of 20% to 50%, an average pore size of 10 to 50 nm, a wet true density of 1.05 to 1.15 g / mL, a height-to-diameter ratio of the organic exchange resin column of 3 to 6:1, and an operating flow rate of 2 to 10 BV / h.

[0049] Furthermore, in step S4, the alkali is one or more of sodium hydroxide, ammonia water, and lime, and the pH adjustment range is 9.0 to 12.0; the ammonia nitrogen remover is a powder uniformly mixed with 10% to 40% adsorbent, 30% to 60% oxidant, and 20% to 45% coagulant, and the dosage is 1 to 10 g / L; the adsorbent is one or more of struvite, diatomaceous earth, molecular sieve, activated carbon, activated alumina, and zeolite; the coagulant is polymerized One or more of aluminum chloride, aluminum sulfate, ferric sulfate, ferric chloride, polymerized ferric sulfate, and polyacrylamide; the oxidant is one or more of bleaching powder, sodium hypochlorite, calcium hypochlorite, potassium permanganate, potassium perchlorate, potassium perchlorate, potassium ferrate, sodium persulfate, and benzoyl peroxide; the aeration mixing reaction time is 1.0 to 4.0 h, the static sedimentation time is 0.5 to 2.0 h, and the coagulant aid is polyacrylamide, and the dosage is 1 to 20 mg / L.

[0050] Example 1

[0051] Take 2L of tungsten slag wastewater, add 120g of ammonium oxalate, stir the reaction for 1h, let it stand for 30min to obtain intermediate water and iron oxalate precipitate.

[0052] Take 1L of intermediate water 1 and slowly flow it from top to bottom through the silver-copper exchange resin column to obtain intermediate water 2. The silver-copper exchange resin column is filled with gel-type strong acid cation exchange resin. The silver-copper exchange resin is pretreated with acid washing, alkali washing and water washing before the first use. The diameter of the silver-copper exchange resin column is 80mm and the height is 240mm.

[0053] The intermediate effluent 2 is slowly passed from top to bottom through the organic exchange resin column to obtain the intermediate effluent 3. The organic exchange resin column is filled with cross-linked polystyrene macroporous adsorption resin. The organic exchange resin is pretreated by three steps of acid washing, alkali washing and water washing before the first use. The silver-copper exchange resin column has a diameter of 80 mm and a height of 240 mm.

[0054] Take 500mL of the middle water, add 50% sodium hydroxide solution to adjust the pH to 10.0, add 2.0g of ammonia nitrogen remover, stir and react for 2h, then add 0.5mL of 1% polyacrylamide solution, stir slowly to mix evenly, let stand for 30min, and take the supernatant to test the water quality.

[0055] Embodiment Test water quality is as follows:

[0056] Table 1 Experimental data of Example 1

[0057]

[0058]

[0059] In the tungsten slag wastewater test of this embodiment, the raw water TOC is 645 mg / L, the ammonia nitrogen is 836 mg / L, the organic matter (extractant) is 42 mg / L, the total iron is 17000 mg / L, the total silver is 12.50 mg / L, the total copper is 473.75 mg / L, and the salinity is 15% to 18%. The raw water has high salinity, and conventional biological methods are difficult to treat high-salinity wastewater.

[0060] After treatment by this process, the final effluent organic matter concentration is <1mg / L, TOC is 98.2mg / l, total iron is 12mg / L, total silver is 0.19mg / L, total copper is 8.50mg / L, ammonia nitrogen is 13mg / L, and treating 1 ton of wastewater can recover 17.0kg of iron, 12.31g of silver, 465.25g of copper and 546.8g of organic matter (extractant).

[0061] Example 2

[0062] Take 1L of tungsten slag wastewater, a total of 4 parts, add 17g, 34g, 51g, and 68g of ammonium oxalate respectively, stir and react for 1h, let it stand for 30min, and obtain intermediate water and iron oxalate precipitate. Dry the iron oxalate precipitate at 80℃ to constant weight. The measured data are as follows.

[0063] Table 2 Experimental data of Example 2

[0064]

[0065] This example shows that ammonium oxalate can effectively remove iron ions in tungsten slag wastewater, and the removal rate of iron ions can reach 99.57%, producing iron oxalate, which has recycling value.

[0066] Example 3

[0067] Take 2500mL of the third intermediate water, add 50% sodium hydroxide solution to adjust the pH to 10.0, divide it into 5 portions, 500mL each, add 0g, 0.5g, 1.0g, 2.0g, 3.0g of ammonia nitrogen remover respectively, the dosage of ammonia nitrogen remover is 0g / L, 1.0g / L, 2.0g / L, 4.0g / L, 6.0g / L respectively, stir and react for 2h, then add 0.5mL of 1% polyacrylamide solution respectively, stir slowly to mix evenly, let stand for 30min, take the supernatant to test the water quality.

[0068] Table 3 Experimental data of Example 3

[0069]

[0070] This example shows that the ammonia nitrogen remover can effectively remove ammonia nitrogen in tungsten slag wastewater. When the dosage of the ammonia nitrogen remover is 4.0 g / L, the removal rate of ammonia nitrogen can reach 98.61%.

[0071] In summary, the present invention provides a method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter, including four steps of precipitation, primary adsorption, secondary adsorption and oxidative deamination. Specifically, ammonium oxalate is first added to the tungsten slag wastewater to obtain intermediate effluent one and iron oxalate precipitate; then the intermediate effluent one is passed through a silver-copper exchange resin column to remove silver and copper in the wastewater to obtain intermediate effluent two; then the intermediate effluent two is passed through an organic exchange resin column to remove organic matter in the wastewater to obtain intermediate effluent three; finally, alkali is first added to the intermediate effluent three to adjust the pH value to alkaline, and then an ammonia nitrogen remover is added to aerate the reaction, and a PAM coagulant is added after the reaction is completed, and the sludge and final effluent are obtained, effectively removing ammonia nitrogen in the wastewater. The present invention combines physical and chemical methods to effectively remove pollutants such as heavy metals, ammonia nitrogen, COD, etc. in acidic high-salt tungsten slag wastewater, realizes the recycling of iron, silver, copper, etc. and organic extractants, saves resources, and protects the environment; at the same time, it realizes simple and effective treatment of wastewater, and the treatment and recovery of heavy metals and organic matter can be realized without adjusting the pH value in the front stage of the process, the process flow is simple, and cost is saved.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter, characterized in that: The following steps are involved: S1: Add ammonium oxalate to the tungsten slag wastewater, stir to react, and let it stand to precipitate, to obtain intermediate water and iron oxalate precipitate; S2: passing the intermediate effluent 1 obtained in step S1 through a silver-copper exchange resin column to remove silver and copper in the wastewater to obtain intermediate effluent 2; S3: passing the intermediate effluent II obtained in step S2 through an organic exchange resin column to remove organic matter in the wastewater, thereby obtaining intermediate effluent III; S4: firstly add alkali to the intermediate effluent obtained in step S3 to adjust the pH value, then add an ammonia nitrogen remover, introduce air for aeration and mixing reaction to remove the ammonia nitrogen in the wastewater; after the reaction is completed, add a coagulant, slowly stir evenly, and then let it stand to precipitate to obtain the final effluent and sludge.

2. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 1, characterized in that: In step S1, the mass ratio of the ammonium oxalate to the iron in the tungsten slag wastewater is 3-4:1, the stirring reaction time is 0.5-1.0h, and the static precipitation time is 0.5-2.0h.

3. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 1, characterized in that: In step S2, the silver-copper exchange resin column is filled with a gel-type strongly acidic cation exchange resin, the total exchange capacity is 1.0-3.0 mmol / mL wet resin, the wet true density is 1.05-1.15 g / mL, the height-to-diameter ratio of the silver-copper exchange resin column is 3-6:1, and the operating flow rate is 2-10 BV / h.

4. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 1, characterized in that: The method further includes step S5 after step S2: after the silver-copper exchange resin column is saturated with adsorption, injecting a silver-copper desorbent into the silver-copper exchange resin column to regenerate the silver-copper exchange resin, transferring the silver and copper ions adsorbed by the silver-copper exchange resin to a silver-copper desorption liquid for discharge, and regenerating the silver-copper exchange resin for reuse; adding elemental copper powder to the silver-copper desorption liquid, stirring for reaction, obtaining elemental silver and a copper-containing desorption liquid, and then electrolyzing the copper-containing desorption liquid to obtain elemental copper.

5. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 4, characterized in that: In step S5, the silver-copper desorbent is one or more of nitric acid, sulfuric acid, hydrofluoric acid and hydrochloric acid, with a concentration of 4% to 15%; the regeneration flow rate of the silver-copper exchange resin column is 1 to 4 BV / h.

6. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 1, characterized in that: In step S3, the organic exchange resin column is filled with a cross-linked polystyrene macroporous adsorption resin having a specific surface area of ​​200 to 1200 m 2 / g, a pore size of 20% to 50%, an average pore size of 10 to 50 nm, a wet true density of 1.05 to 1.15 g / mL, a height-to-diameter ratio of the organic exchange resin column of 3 to 6:1, and an operating flow rate of 2 to 10 BV / h.

7. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 1, characterized in that: After step S3, step S6 is also included: after the organic exchange resin column is saturated with adsorption, an organic desorbent is injected into the organic exchange resin column to regenerate the organic exchange resin, and the regeneration flow rate is 1 to 4 BV / h; the organic matter adsorbed by the organic exchange resin is transferred to a desorption liquid containing organic matter for discharge, and the organic exchange resin column is reused after regeneration; the organic desorption liquid is heated for distillation, and the organic desorbent is separated in the form of gas, which is collected and reused for the regeneration of the organic exchange resin, and the generated organic matter is recycled.

8. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 7, characterized in that: In step S6, the organic desorbent is methanol, and the distillation temperature is 70°C.

9. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 1, characterized in that: In step S4, the ammonia nitrogen remover is a powder uniformly mixed with 10% to 40% adsorbent, 30% to 60% oxidant, and 20% to 45% coagulant, and the dosage is 1 to 10 g / L. The adsorbent is one or more of struvite, diatomaceous earth, molecular sieve, activated carbon, activated alumina, and zeolite. The coagulant is one or more of polyaluminum chloride, aluminum sulfate, ferric sulfate, ferric chloride, polyferric sulfate, and polyacrylamide. The oxidant is one or more of bleaching powder, sodium hypochlorite, calcium hypochlorite, potassium permanganate, potassium perchlorate, potassium perchlorate, potassium ferrate, sodium persulfate, and benzoyl peroxide. The aeration mixing reaction time is 1.0 to 4.0 h, and the static sedimentation time is 0.5 to 2.0 h.

10. The method for treating acidic high-salt tungsten slag wastewater and recovering heavy metals and organic matter according to claim 1, characterized in that: In step S4, the alkali is one or more of sodium hydroxide, ammonia water, and lime, and the pH value is adjusted in the range of 9.0 to 12.0; the coagulant aid is polyacrylamide, and the dosage is 1 to 20 mg / L.

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