A method for treating high-salt wastewater from tungsten smelting

Abstract

The present application belongs to the technical field of wastewater treatment, and particularly relates to a method for treating high-salinity wastewater in tungsten smelting. The present application adopts a combination of demulsifier, ultrasonic and micro-nano bubble aeration to pretreat the high-salinity wastewater in tungsten smelting, and then carries out coagulation-oxidation-micro-nano bubble aeration treatment to deeply degrade the organic matter in the wastewater, removes the suspended solids in the wastewater through a multi-medium filter to reduce the influence on subsequent deep treatment, and finally removes the refractory organic matter through resin deep oil removal. The present application removes the organic matter and most of the impurity elements in the wastewater at the same time, and provides a basis for subsequent resource utilization.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a method for treating high-salt wastewater from tungsten smelting. Background Technology

[0002] Tungsten smelting generates large amounts of high-salinity wastewater containing inorganic salts such as sodium sulfate and sodium chloride, as well as organic pollutants such as extractants, flocculants, and surfactants. Without effective treatment, this wastewater poses a significant threat to the ecological environment and human health. The high salt content of this wastewater offers excellent potential for salt resource recovery, such as through evaporation crystallization and pyrolysis. However, the presence of recalcitrant organic matter results in low purity of the directly recovered salt. Therefore, removing organic matter from high-salinity wastewater is crucial for achieving "zero discharge" and resource recovery of salt. Existing treatment methods focus primarily on desalination, with limited capacity for treating organic matter, making it difficult to effectively treat high-salinity, high-concentration organic wastewater. Furthermore, commonly used methods such as biological, adsorption, Fenton, and electrochemical methods are poorly suited for high-salinity wastewater with high organic matter concentrations, complex wastewater composition, and high oil content. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a method for treating high-salt wastewater from tungsten smelting, which can effectively treat high-salt wastewater from tungsten smelting with high organic matter concentration, complex wastewater composition, and high oil content.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for treating high-salinity wastewater from tungsten smelting, comprising the following steps:

[0006] High-salt wastewater from tungsten smelting, demulsifier and coagulant are mixed and then subjected to ultrasonic treatment and first micro-nano bubble aeration, followed by first static sedimentation to obtain the first supernatant.

[0007] The first supernatant, coagulant and oxidant are mixed, the pH of the resulting mixture is adjusted to 6-7, and after aeration by the second micro-nano bubble, it is allowed to settle to obtain the second supernatant.

[0008] The second supernatant was subjected to multi-media filtration and then resin degreasing treatment to obtain effluent.

[0009] Preferably, the demulsifier is an oil-soluble nonionic demulsifier; the mass of the demulsifier is 0.02 to 0.3% of the mass of the high-salt wastewater from tungsten smelting.

[0010] Preferably, the coagulant is one or more of anionic polyacrylamide, cationic polyacrylamide and nonionic polyacrylamide; the amount of the coagulant added in the high-salt wastewater of tungsten smelting is 0.5 to 1.5 mg / L.

[0011] Preferably, the pH value of the first supernatant is 3 to 4.

[0012] Preferably, the frequency of the ultrasonic generator used in the ultrasonic treatment is 20 kHz, and the amplitude of the transducer surface is 10–80 μm; the duration of the ultrasonic treatment is 10–60 s.

[0013] Preferably, the oxygen flow rate of the first micro-nano bubble aeration is 2–10 kg·m³. 3 / h; the aeration time for the first micro-nano bubble is 30-60 min.

[0014] Preferably, the coagulant is one or more of polyaluminum chloride, nonionic polyacrylamide, polyferric chloride, polyferric sulfate, polyaluminum ferric silicate, and polyaluminum ferric silicate sulfate; the amount of coagulant added to the first supernatant is 0.5 to 2.5 g / L.

[0015] Preferably, the oxidant is hydrogen peroxide; the mass concentration of the hydrogen peroxide is 30%; and the amount of the oxidant added to the first supernatant is 0.5-3 g / L.

[0016] Preferably, the oxygen flow rate of the second micro-nano bubble aeration is 6–15 kg·m³. 3 / h; the aeration time for the second micro-nano bubble is 2-6h.

[0017] Preferably, the filler material used in the multi-media filtration process includes a first filler layer and a second filler layer that are filtered sequentially; the first filler layer is made of granular activated carbon with a particle size of 0.5 to 8 mm laid layer by layer; the second filler layer is made of quartz sand with a particle size of 0.5 to 6 mm laid layer by layer.

[0018] This invention provides a method for treating high-salt wastewater from tungsten smelting, comprising the following steps: mixing high-salt wastewater from tungsten smelting, a demulsifier, and a coagulant aid, sequentially subjecting the mixture to ultrasonic treatment and first micro-nano bubble aeration, followed by a first settling to obtain a first supernatant; mixing the first supernatant, a coagulant, and an oxidant, adjusting the pH of the resulting mixture to 6-7, subjecting it to second micro-nano bubble aeration, followed by a second settling to obtain a second supernatant; and subjecting the second supernatant to multi-media filtration and resin degreasing treatment to obtain effluent.

[0019] This invention employs a combination of demulsifier, ultrasound, and micro / nanobubbles for pretreatment of high-salt wastewater from tungsten smelting. Following this, coagulation-oxidation-micro / nanobubble aeration further degrades organic matter in the wastewater. A multi-media filter removes suspended solids, minimizing their impact on subsequent deep treatment. Finally, resin-based deep oil removal removes recalcitrant organic matter. This invention separates soluble oily organics from water by adding a demulsifier followed by micro / nanobubble aeration. A coagulant is then added to encapsulate and precipitate the oily substances, removing some organic matter and impurities such as fluoride and heavy metals. Adding an oxidant and coagulant, followed by micro / nanobubble aeration, enhances the efficiency of hydroxyl radical generation by the oxidant, further removing organic matter. The coagulant further strengthens the coagulation and sedimentation process, removing organic matter and other impurities. Multi-media filtration utilizes various filter media to remove color, odor, residual chlorine, organic matter, suspended solids, colloids, iron, and other impurities from the wastewater. The resin used in this oil removal treatment possesses both hydrophilic and lipophilic functional groups. The hydrophilic groups demulsify oils, while the lipophilic groups adsorb them. Adsorbed oil droplets accumulate on the resin surface. When a certain amount of oil accumulates, the hydrophilic groups inside the resin push up the saturated lipophilic groups, causing some oil droplets to demulsify and float to the surface, thus completing the oil removal process and achieving oil-water separation. This invention removes most of the impurities in wastewater while removing organic matter, providing a foundation for subsequent resource recovery. The method provided by this invention can effectively treat high-salt tungsten smelting wastewater with high organic matter concentration, complex wastewater composition, and high oil content (kerosene, extractants, and other organic matter), solving the problems in the resource recovery of high-salt tungsten smelting wastewater and exhibiting good economic and environmental compatibility. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method for treating high-salt wastewater from tungsten smelting according to the present invention. Detailed Implementation

[0021] This invention provides a method for treating high-salinity wastewater from tungsten smelting, comprising the following steps:

[0022] High-salt wastewater from tungsten smelting, demulsifier and coagulant are mixed and then subjected to ultrasonic treatment and first micro-nano bubble aeration, followed by first static sedimentation to obtain the first supernatant.

[0023] The first supernatant, coagulant and oxidant are mixed, the pH of the resulting mixture is adjusted to 6-7, and after aeration by the second micro-nano bubble, it is allowed to settle to obtain the second supernatant.

[0024] The second supernatant was subjected to multi-media filtration and then resin degreasing treatment to obtain effluent.

[0025] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0026] This invention mixes high-salt wastewater from tungsten smelting, a demulsifier, and a coagulant, and then sequentially treats it with ultrasound and aerates it with micro-nano bubbles, followed by a first settling period to obtain a first supernatant.

[0027] In this invention, the TOC content in the high-salt wastewater from tungsten smelting is preferably 500-2000 mg / L, more preferably 600 mg / L; the pH value is preferably 2-5, more preferably 3.2; the TDS content is preferably 100-200 g / L, more preferably 156 g / L; the silica content is preferably 50-60 mg / L, more preferably 52 mg / L; the calcium ion content is preferably 30-80 mg / L, more preferably 61 mg / L; the magnesium ion content is preferably 50-100 mg / L, more preferably 87 mg / L; the aluminum ion content is preferably 20-40 mg / L, more preferably 28 mg / L; the total arsenic content is preferably 5-10 mg / L, more preferably 6.5 mg / L; and the fluoride ion content is preferably 300-400 mg / L, more preferably 355 mg / L.

[0028] When the pH value of the high-salinity wastewater from tungsten smelting is <3, this invention preferably adjusts the pH value of the high-salinity wastewater from tungsten smelting to ≥3; the reagent used to adjust the pH value of the high-salinity wastewater from tungsten smelting is preferably sodium hydroxide. A pH that is too low is not conducive to the removal of organic matter by demulsifiers and coagulants. Therefore, this invention adjusts the pH value of the high-salinity wastewater from tungsten smelting to ≥3 to improve the removal effect of demulsifiers and coagulants on organic matter.

[0029] In this invention, the demulsifier is preferably an oil-soluble nonionic demulsifier, more preferably a polymer formed by polymerization of alkylphenol resin (AR resin) with polyethylene oxide and polypropylene oxide, and most preferably Yangjing PYJ-301 type demulsifier; the mass of the demulsifier is preferably 0.02-0.3% of the mass of the high-salt wastewater from tungsten smelting, more preferably 0.05-0.1%.

[0030] The demulsifier used in this invention is a surfactant that can disrupt the structure of an emulsified liquid, thereby separating the different phases in the emulsion. Crude oil demulsification refers to using the chemical action of a demulsifier to separate the oil and water in an emulsified oil-water mixture, achieving the purpose of crude oil dehydration and ensuring the water content standard for crude oil exports.

[0031] In this invention, the coagulant is preferably one or more of anionic polyacrylamide, cationic polyacrylamide and nonionic polyacrylamide, more preferably anionic polyacrylamide; the amount of the coagulant added to the high-salt wastewater of tungsten smelting is preferably 0.5-1.5 mg / L, more preferably 0.6-0.8 mg / L.

[0032] In this invention, the mixing of high-salt tungsten smelting wastewater, demulsifier, and coagulant is preferably carried out under stirring conditions; the stirring rate is preferably 200-400 rpm, more preferably 300 rpm; the stirring time is preferably 30-120 min, more preferably 60-90 min.

[0033] During the stirring process, the main reaction occurs between the demulsifier and the oily substances in the high-salt wastewater.

[0034] The coagulant aid used in this invention facilitates the rapid sedimentation of demulsifiers, improving treatment efficiency. Polyacrylamide (PAM) is a polymer compound that primarily functions through: 1. Flocculation: PAM can flocculate suspended substances through charge neutralization and bridging adsorption. 2. Adhesion: It can act as an adhesive through mechanical, physical, and chemical means. 3. Drag Reduction: PAM can effectively reduce the frictional resistance of fluids; adding trace amounts of PAM to water can reduce drag by 50-80%. 4. Thickening: PAM has a thickening effect under both neutral and acidic conditions; it is easily hydrolyzed when the pH is above 10. The thickening effect is more pronounced when it forms a semi-network structure.

[0035] In this invention, the frequency of the ultrasonic generator used for ultrasonic treatment is preferably 20 kHz, the amplitude of the transducer surface is preferably 10-80 μm, more preferably 20-60 μm, and the duration of ultrasonic treatment is preferably 10-60 s, more preferably 20-50 s.

[0036] This invention employs ultrasonic treatment for demulsification. Ultrasonic demulsification technology is characterized by low energy consumption, no pollution, and rapid efficiency, making it an effective method for treating high-viscosity heavy oil emulsions. When ultrasound acts on a fluid, it causes displacement and collisions between the media, rapidly achieving demulsification and improving dehydration efficiency. Ultrasound exerts mechanical, cavitation, and thermal effects on media placed in an ultrasonic field. Ultrasonic demulsification and dehydration of crude oil primarily utilizes the mechanical and thermal effects of ultrasound on the media. The mechanical action of ultrasound causes displacement and collisions among media particles, leading to the aggregation of small droplets into larger droplets. The increased droplet size allows for sedimentation and separation under gravity. The thermal effect of ultrasound reduces the strength of the oil-water interface film in the crude oil emulsion and decreases the viscosity of the crude oil, thus achieving demulsification and dehydration. Compared to other methods, ultrasonic demulsification technology effectively lowers the demulsification and dehydration temperature, achieving demulsification at room temperature, thereby reducing the use of heating equipment (such as complex high-voltage electric dehydrators) and lowering processing energy consumption.

[0037] In this invention, the oxygen flow rate for the first micro-nano bubble aeration is preferably 2–10 kg·m³. 3 / h, more preferably 3-5 kg·m 3 / h; the aeration time of the first micro-nano bubble is preferably 30-60 min, more preferably 40-50 min.

[0038] The micro / nanobubble aeration method used in this invention can improve the oxidation efficiency of hydrogen peroxide. Micro / nanobubbles are extremely fine bubbles with a diameter of less than 50 μm. They rise slowly in water, have a long residence time, high dissolution efficiency, and possess characteristics such as self-oxygenation, negative charge, and abundance of highly oxidizing free radicals. These characteristics enable micro / nanobubbles to improve the oxidation efficiency of hydrogen peroxide.

[0039] In this invention, the first settling time is preferably 1 to 5 hours, more preferably 2 to 4 hours; the pH value of the first supernatant is preferably 3 to 4.

[0040] After obtaining the first supernatant, the present invention mixes the first supernatant, coagulant and oxidant, adjusts the pH value of the resulting mixture to 6-7, aerates it with a second micro-nano bubble, and then allows it to settle to obtain the second supernatant.

[0041] In this invention, the pH value of the mixture obtained by mixing the first supernatant, coagulant and oxidant is adjusted to the above range, and the coagulant has the best effect in removing organic matter from wastewater.

[0042] In this invention, the coagulant is preferably one or more of polyaluminum chloride (PAC), nonionic polyacrylamide (PAM), polyferric chloride (PFC), polyferric sulfate (PFS), polyferric aluminum silicate (PSAF), and polyferric aluminum silicate sulfate (PSSAF), more preferably polyferric aluminum silicate (PSAF) and polyferric aluminum silicate sulfate (PSSAF); the mass ratio of polyferric aluminum silicate (PSAF) to polyferric aluminum silicate sulfate (PSSAF) is preferably 1 to 5:1, more preferably 2:1; the amount of coagulant added to the first supernatant is preferably 0.5 to 2.5 g / L, more preferably 1 to 2 g / L.

[0043] This invention utilizes the bridging effect of coagulants to demulsify emulsified oil, forming microparticle oil droplets that are then aggregated and adsorbed by the coagulant. In oily wastewater, the non-polar ends of surfactants are adsorbed within the oil droplets, while the polar ends extend into the water. These polar ends continue to ionize in the water, resulting in a negatively charged layer surrounding the oil droplets. This hinders the adsorption of oil droplets onto the surface of air bubbles, ultimately forming a stable oil-in-water system. The addition of coagulants, besides compressing the electric double layer to lower the potential, also provides adsorption-charge neutralization and adsorption-bridging effects, achieving the desired coagulation and demulsification results.

[0044] In this invention, the oxidant is preferably hydrogen peroxide; the mass concentration of the hydrogen peroxide is preferably 30%; the amount of the oxidant added to the first supernatant is preferably 0.5-3 g / L, more preferably 1-2 g / L.

[0045] In this invention, the pH value of the obtained mixture is preferably adjusted to 6.2 to 6.8, and the reagent used for adjusting the pH value of the obtained mixture is preferably sodium hydroxide.

[0046] In this invention, the oxygen flow rate for the second micro-nano bubble aeration is preferably 6–15 kg·m³. 3 / h, more preferably 8–12 kg·m 3 / h; the aeration time of the second micro-nano bubble is preferably 2 to 6 hours, more preferably 3 to 5 hours.

[0047] In this invention, the second settling time is preferably 1 to 5 hours, more preferably 2 to 4 hours.

[0048] After obtaining the second supernatant, the present invention performs multi-media filtration on the second supernatant and then resin degreasing treatment to obtain effluent.

[0049] In this invention, the filler material used in the multi-media filtration process preferably includes a first filler layer and a second filler layer that are filtered sequentially; the first filler layer is preferably composed of granular activated carbon with a particle size of 0.5 to 8 mm laid layer by layer, more preferably 1 to 5 mm; the second filler layer is preferably composed of quartz sand with a particle size of 0.5 to 6 mm laid layer by layer, more preferably 1 to 5 mm; the thickness of the first filler layer is preferably 400 to 600 mm, more preferably 500 mm; the thickness of the second filler layer is preferably 600 to 900 mm, more preferably 800 mm.

[0050] The upper filter media is activated carbon, used to remove color, odor, residual chlorine, and organic matter. Its main mechanism of action is adsorption; activated carbon is a man-made adsorbent. Due to its well-developed microporous structure and large specific surface area, activated carbon has a strong adsorption capacity for dissolved organic matter in water, such as benzene and phenolic compounds. It also shows good removal effects for organic pollutants that are difficult to remove using biological and chemical methods, such as color, odor, surfactants, synthetic detergents, and dyes. Granular activated carbon is effective for removing Ag from water. 3+ Cd 2+ CrO4 2- The plasma removal rate reaches over 85%. After passing through the activated carbon filter bed, the suspended solids (SS) in the water are less than 0.1 mg / L, the COD removal rate is generally 40-50%, and the free chlorine is less than 0.1 mg / L. Using quartz sand as the lower filter media effectively removes suspended solids from the water and has a significant removal effect on colloids, iron, organic matter, and other pollutants. It has advantages such as low filtration resistance, large specific surface area, strong acid and alkali resistance, oxidation resistance, a pH range of 2-13, and good anti-fouling properties. The filter media has strong adaptability to raw water concentration, operating conditions, and pretreatment processes; that is, during filtration, the filter bed automatically forms a loose upper and dense lower state, which helps to ensure the quality of the effluent under various operating conditions. During backwashing, the filter media fully disperses, resulting in good cleaning effect. Sand filters have advantages such as fast filtration speed, high filtration accuracy, and large dirt-holding capacity.

[0051] In this invention, the resin used for the resin degreasing treatment is preferably a polymeric porous adsorption resin, more preferably a styrene-divinylphenyl skeleton adsorption resin; the flow rate of the resin degreasing treatment is preferably 2-6 BV / h, more preferably 3-5 BV / h; the resin degreasing treatment process preferably involves filling the resin into an ion exchange column, and pumping the second supernatant after multi-media filtration through the resin-filled ion exchange column from top to bottom for adsorption, resulting in saturated resin and effluent; the diameter-to-height ratio of the ion exchange column is preferably 1:5; the saturated resin is preferably regenerated with a desorbent and reused. This invention uses resin to dynamically adsorb organic matter in wastewater, achieving deep removal of organic matter from the wastewater. Through the resin-filled ion exchange column, the oil content in the wastewater is reduced to below 1 mg / L.

[0052] The resin used in the oil removal process of this invention has both hydrophilic and lipophilic functional groups. The hydrophilic group has a demulsifying function for oils, while the lipophilic group has an adsorption function for oils. The adsorbed oil droplets gather on the resin surface. When a certain amount of oil accumulates, the hydrophilic group inside the resin pushes up the lipophilic group that is saturated with oil, causing some of the oil droplets to demulsify and thus the oil droplets detach from the resin and float to the surface, completing the oil removal process and achieving the effect of oil-water separation.

[0053] In this invention, the TOC content in the effluent is preferably <10 mg / L, more preferably 4.8-8.9 mg / L; the pH value is preferably 6.5-7.2, more preferably 6.8-7; the TDS content is preferably 145-148 g / L, more preferably 146-147 g / L; the silica content is preferably 10.6-16.5 mg / L, more preferably 12-15 mg / L; the calcium ion content is preferably <10 mg / L; the magnesium ion content is preferably <10 mg / L; the aluminum ion content is preferably <10 mg / L; the total arsenic content is preferably <0.5 mg / L; and the fluoride ion content is more preferably <10 mg / L.

[0054] In this invention, the effluent is preferably utilized for resource recovery, more preferably for direct evaporation and crystallization to prepare sodium sulfate, or for electrodialysis to prepare acids and bases after impurity removal. This invention does not impose any particular limitation on the resource recovery method of the effluent; it can be determined according to actual needs.

[0055] Figure 1 This is a flow chart of the method for treating high-salinity wastewater from tungsten smelting according to the present invention. Figure 1 It is understood that the present invention treats high-salt wastewater by demulsification, ultrasound, and air flotation (micro-nano bubble aeration), followed by coagulation, oxidation, and air flotation treatment. Finally, the wastewater is treated by multi-media filtration and resin oil removal, and the resulting water can be recycled as wastewater.

[0056] This invention employs a combination of demulsifiers, ultrasound, and micro / nano bubble aeration for pretreatment of high-salinity wastewater from tungsten smelting. Following this, coagulation-oxidation-micro / nano bubble aeration further degrades organic matter in the wastewater. A multi-media filter removes suspended solids, minimizing their impact on subsequent advanced treatment. Finally, resin-based deep oil removal removes recalcitrant organic matter. This invention removes most impurities from the wastewater while simultaneously removing organic matter, laying the foundation for subsequent resource recovery. The method provided by this invention effectively treats high-salinity tungsten smelting wastewater with high organic matter concentration, complex composition, and high oil content, solving the problems associated with the resource recovery of high-salinity tungsten smelting wastewater and demonstrating good economic efficiency and environmental compatibility.

[0057] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0058] Example 1

[0059] Taking the treatment of high-salinity wastewater from a tungsten smelting plant as an example, tests showed that before treatment, the TOC content of the wastewater was 600 mg / L, the pH value was 3.2, the TDS content was 156 g / L, the silica content was 52 mg / L, the calcium ion content was 61 mg / L, the magnesium ion content was 87 mg / L, the aluminum ion content was 28 mg / L, the fluoride ion content was 355 mg / L, and the total arsenic content was 6.5 mg / L. When production fluctuates, its chemical composition also changes to some extent.

[0060] The high-salt wastewater from tungsten smelting will be treated using the method of the present invention. The treatment steps are as follows: Figure 1 As shown, it specifically includes:

[0061] (1) Demulsification-ultrasound-air flotation treatment: The above-mentioned high-salt wastewater from tungsten smelting was collected into a wastewater tank, and demulsifier and coagulant were added. The mixture was stirred at 300 rpm for 30 min, then ultrasonically treated for 10 s, aerated with the first micro-nano bubbles for 30 min, and then allowed to settle for 2 h to obtain the first supernatant (pH 3-4).

[0062] The demulsifier (Yangjing PYJ-301 type demulsifier) ​​is an oil-soluble nonionic demulsifier polymerized from alkylphenol resin (AR resin) and polyoxyethylene and polyoxypropylene, and the mass of the demulsifier is 0.06% of the mass of the high-salt wastewater from tungsten smelting; the coagulant is anionic polyacrylamide, and the amount of coagulant added to the high-salt wastewater from tungsten smelting is 0.5 mg / L; the frequency of the ultrasonic generator used in the ultrasonic treatment is 20 kHz, and the amplitude of the transducer surface is 30 μm; the oxygen flow rate of the first micro-nano bubble aeration is 5 kg / m³. 3 ·h;

[0063] (2) Coagulation-oxidation-flotation treatment: The first supernatant is collected into the reaction tank, coagulant and oxidant are added, and the pH value of the resulting mixture is adjusted to 6.5 with sodium hydroxide. After the second micro-nano bubble aeration for 2 hours, the second settling is allowed to settle for 1 hour to initially remove fluoride and organic matter, and the second supernatant is obtained.

[0064] The coagulant is a mixture of polyaluminum ferric silicate (PSAF) and polyaluminum ferric silicate sulfate (PSSAF) in a mass ratio of 5:1; the amount of coagulant added to the first supernatant is 0.5 g / L; the oxidant is hydrogen peroxide with a mass concentration of 30%; the amount of hydrogen peroxide added to the first supernatant is 0.5 g / L; and the oxygen flow rate of the second micro-nano bubble aeration is 8 kg / m³. 3 ·h;

[0065] (3) Multi-media filtration and resin deep oil removal: The second supernatant is introduced into a multi-media filter and treated by multi-media filtration. The filtered second supernatant is then treated by resin oil removal resin column (styrene-divinylphenyl skeleton adsorption resin) to obtain effluent.

[0066] The multi-media filtration process uses a first and second packing layer that are sequentially filtered. The first packing layer is made of granular activated carbon with a particle size of 2-4 mm, layer by layer, with a thickness of 500 mm. The second packing layer is made of quartz sand with a particle size of 2-4 mm, layer by layer, with a thickness of 800 mm. The flow rate of the resin degreasing process is 5 BV / h. The resin degreasing process involves filling an ion exchange column with resin (styrene-divinylphenyl skeleton adsorption resin), and pumping the second supernatant after multi-media filtration through the resin-filled ion exchange column from top to bottom for adsorption, resulting in saturated resin and effluent. The diameter-to-height ratio of the ion exchange column is 1:5. The saturated resin is regenerated with a desorbent and reused.

[0067] Example 2

[0068] Taking the treatment of high-salinity wastewater from a tungsten smelting plant as an example, tests showed that before treatment, the TOC content of the wastewater was 600 mg / L, the pH value was 3.2, the TDS content was 156 g / L, the silica content was 52 mg / L, the calcium ion content was 61 mg / L, the magnesium ion content was 87 mg / L, the aluminum ion content was 28 mg / L, the fluoride ion content was 355 mg / L, and the total arsenic content was 6.5 mg / L. When production fluctuates, its chemical composition also changes to some extent.

[0069] The high-salt wastewater from tungsten smelting will be treated using the method of the present invention. The treatment steps are as follows: Figure 1 As shown, it specifically includes:

[0070] (1) Demulsification-ultrasound-air flotation treatment: The above-mentioned high-salt wastewater from tungsten smelting was collected into a wastewater tank, and demulsifier and coagulant were added. The mixture was stirred at 300 rpm for 60 min, then ultrasonically treated for 10 s, aerated with the first micro-nano bubbles for 30 min, and then allowed to settle for 2 h to obtain the first supernatant (pH 3-4).

[0071] The demulsifier (Yangjing PYJ-301 type demulsifier) ​​is an oil-soluble nonionic demulsifier polymerized from alkylphenol resin (AR resin) and polyoxyethylene and polyoxypropylene, and the mass of the demulsifier is 0.3% of the mass of the high-salt wastewater from tungsten smelting; the coagulant is anionic polyacrylamide, and the amount of coagulant added to the high-salt wastewater from tungsten smelting is 1 mg / L; the frequency of the ultrasonic generator used in the ultrasonic treatment is 20 kHz, and the amplitude of the transducer surface is 30 μm; the oxygen flow rate of the first micro-nano bubble aeration is 5 kg / m³. 3 ·h;

[0072] (2) Coagulation-oxidation-flotation treatment: The first supernatant is collected into the reaction tank, coagulant and oxidant are added, and the pH value of the resulting mixture is adjusted to 6.8 with sodium hydroxide. After the second micro-nano bubble aeration for 2 hours, the second settling is allowed to settle for 1 hour to initially remove fluoride and organic matter, and the second supernatant is obtained.

[0073] The coagulant is a mixture of polyaluminum ferric silicate (PSAF) and polyaluminum ferric silicate sulfate (PSSAF) in a mass ratio of 2:1; the amount of coagulant added to the first supernatant is 0.6 g / L; the oxidant is hydrogen peroxide with a mass concentration of 30%; the amount of hydrogen peroxide added to the first supernatant is 1 g / L; and the oxygen flow rate of the second micro-nano bubble aeration is 8 kg / m³. 3 ·h;

[0074] (3) Multi-media filtration and resin deep oil removal: The second supernatant is introduced into a multi-media filter and treated by multi-media filtration. The filtered second supernatant is then treated by resin oil removal resin column (styrene-divinylphenyl skeleton adsorption resin) to obtain effluent.

[0075] The multi-media filtration process uses a first and second packing layer that are sequentially filtered. The first packing layer is made of granular activated carbon with a particle size of 2-4 mm, layer by layer, with a thickness of 500 mm. The second packing layer is made of quartz sand with a particle size of 2-4 mm, layer by layer, with a thickness of 800 mm. The flow rate of the resin degreasing process is 5 BV / h. The resin degreasing process involves filling an ion exchange column with resin (styrene-divinylphenyl skeleton adsorption resin), and pumping the second supernatant after multi-media filtration through the resin-filled ion exchange column from top to bottom for adsorption, resulting in saturated resin and effluent. The diameter-to-height ratio of the ion exchange column is 1:5. The saturated resin is regenerated with a desorbent and reused.

[0076] Example 3

[0077] Taking the treatment of high-salinity wastewater from a tungsten smelting plant as an example, tests showed that before treatment, the TOC content of the wastewater was 600 mg / L, the pH value was 3.2, the TDS content was 156 g / L, the silica content was 52 mg / L, the calcium ion content was 61 mg / L, the magnesium ion content was 87 mg / L, the aluminum ion content was 28 mg / L, the fluoride ion content was 355 mg / L, and the total arsenic content was 6.5 mg / L. When production fluctuates, its chemical composition also changes to some extent.

[0078] The high-salt wastewater from tungsten smelting will be treated using the method of the present invention. The treatment steps are as follows: Figure 1 As shown, it specifically includes:

[0079] (1) Demulsification-ultrasound-air flotation treatment: The above-mentioned high-salt wastewater from tungsten smelting was collected into a wastewater tank, and demulsifier and coagulant were added. The mixture was stirred at 300 rpm for 30 min, then ultrasonically treated for 10 s, aerated with the first micro-nano bubbles for 30 min, and then allowed to settle for 2 h to obtain the first supernatant (pH 3-4).

[0080] The demulsifier (Yangjing PYJ-301 type demulsifier) ​​is an oil-soluble nonionic demulsifier polymerized from alkylphenol resin (AR resin) and polyoxyethylene and polyoxypropylene, and the mass of the demulsifier is 0.06% of the mass of the high-salt wastewater from tungsten smelting; the coagulant is anionic polyacrylamide, and the amount of coagulant added to the high-salt wastewater from tungsten smelting is 1.5 mg / L; the frequency of the ultrasonic generator used in the ultrasonic treatment is 20 kHz, and the amplitude of the transducer surface is 30 μm; the oxygen flow rate of the first micro-nano bubble aeration is 5 kg / m³. 3 ·h;

[0081] (2) Coagulation-oxidation-flotation treatment: The first supernatant is collected into the reaction tank, coagulant, oxidant and catalyst are added, the pH value of the resulting mixture is adjusted to 6.2 with sodium hydroxide, the second micro-nano bubble aeration is performed for 2 hours, and the second settling is performed for 1 hour to initially remove fluoride and organic matter, and the second supernatant is obtained.

[0082] The coagulant is a mixture of polyaluminum ferric silicate (PSAF) and polyaluminum ferric sulfate (PSSAF) in a mass ratio of 2:1; the amount of coagulant added to the first supernatant is 1 g / L; the oxidant is hydrogen peroxide with a mass concentration of 30%; the amount of hydrogen peroxide added to the first supernatant is 1.5 g / L; and the oxygen flow rate of the second micro-nano bubble aeration is 8 kg / m³. 3 ·h;

[0083] (3) Multi-media filtration and resin deep oil removal: The second supernatant is introduced into a multi-media filter and treated by multi-media filtration. The filtered second supernatant is then treated by resin oil removal resin column (styrene-divinylphenyl skeleton adsorption resin) to obtain effluent.

[0084] The multi-media filtration process uses a first packing layer and a second packing layer. The first packing layer is made of granular activated carbon with a particle size of 2-4 mm, laid layer by layer, with a thickness of 500 mm. The second packing layer is made of quartz sand with a particle size of 2-4 mm, laid layer by layer, with a thickness of 800 mm. The flow rate of the resin degreasing process is 3 BV / h. The resin degreasing process involves filling an ion exchange column with resin (styrene-divinylphenyl skeleton adsorption resin), and pumping the second supernatant after multi-media filtration through the resin-filled ion exchange column from top to bottom for adsorption, resulting in saturated resin and effluent. The diameter-to-height ratio of the ion exchange column is 1:5. The saturated resin is regenerated with a desorbent and reused.

[0085] Comparative Example 1

[0086] The difference from Example 1 is that ultrasonic and micro-nano bubble aeration treatment is not performed in step (1), but the rest is the same as in Example 1.

[0087] Comparative Example 2

[0088] The difference from Example 1 is that step (2) lacks a coagulant, while the rest is the same as Example 1.

[0089] Comparative Example 3

[0090] The difference from Example 1 is that the resin degreasing treatment is missing; otherwise, the contents are the same as in Example 1.

[0091] Performance testing

[0092] To verify the effectiveness of the technical solution of the present invention, high-salt wastewater from tungsten smelting was treated according to the above embodiments and comparative examples, and the quality of the treated effluent was then tested. The results are shown in Table 1.

[0093] Table 1. Water quality analysis before and after treatment in Examples 1-3 and Comparative Examples 1-3.

[0094]

[0095]

[0096] As shown in Table 1 above, the TOC content in the effluent from the high-salinity wastewater of tungsten smelting treated by the methods in Examples 1-33 is less than 10 mg / L, and the contents of heavy metals, fluorine, and silicon are also low. It can be directly evaporated and crystallized to prepare sodium sulfate, or further purified by conventional methods followed by electrodialysis to prepare acids and bases. This invention solves the problem of the difficulty in resource recovery from high-salinity wastewater of tungsten smelting due to its high impurity content through advanced treatment, and has significant environmental and economic benefits.

[0097] As shown in Table 1, in Comparative Example 1, where ultrasonic and micro-nano aeration were not performed in step (1) and other conditions were the same as in Example 1, the concentrations of TOC and SiO2 in the effluent increased significantly. In Comparative Example 2, where coagulant was absent in step (2) and other conditions were the same as in Example 1, the concentrations of arsenic, TOC, and SiO2 in the effluent increased significantly. In Comparative Example 3, where resin oil removal was absent and other conditions were the same as in Example 1, the concentration of TOC in the effluent increased significantly to 25.1 mg / L.

[0098] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for treating high-salinity wastewater from tungsten smelting, characterized in that, Includes the following steps: (1) Demulsification-ultrasound-air flotation treatment: High-salt wastewater from tungsten smelting was collected in a wastewater tank, and demulsifier and coagulant were added. The mixture was stirred at 300 rpm for 30 min, then ultrasonically treated for 10 s, aerated with micro-nano bubbles for 30 min, and then allowed to settle for 2 h to obtain the first supernatant with a pH of 3-4. Before treatment, the high-salt wastewater from tungsten smelting had a TOC content of 600 mg / L, a pH of 3.2, a TDS content of 156 g / L, a silica content of 52 mg / L, a calcium ion content of 61 mg / L, a magnesium ion content of 87 mg / L, an aluminum ion content of 28 mg / L, a fluoride ion content of 355 mg / L, and a total arsenic content of 6.5 mg / L. The demulsifier is an oil-soluble nonionic demulsifier polymerized from alkylphenol resin (AR) and polyoxyethylene and polyoxypropylene, and its mass is 0.06% of the mass of the high-salt tungsten smelting wastewater. The coagulant is anionic polyacrylamide, and its addition amount in the high-salt tungsten smelting wastewater is 1.5 mg / L. The ultrasonic generator used for ultrasonic treatment has a frequency of 20 kHz and a transducer surface amplitude of 30 μm. The oxygen flow rate for the first micro-nano bubble aeration is 5 kg / m³. 3 ·h; (2) Coagulation-oxidation-flotation treatment: The first supernatant is collected into the reaction tank, coagulant, oxidant and catalyst are added, the pH value of the resulting mixture is adjusted to 6.2 with sodium hydroxide, the second micro-nano bubble aeration is performed for 2 hours, and the second settling is performed for 1 hour to initially remove fluoride and organic matter, and the second supernatant is obtained. The coagulant is a mixture of polyaluminum ferric silicate (PSAF) and polyaluminum ferric sulfate (PSSAF) in a mass ratio of 2:1; the amount of coagulant added to the first supernatant is 1 g / L; the oxidant is hydrogen peroxide with a mass concentration of 30%; the amount of hydrogen peroxide added to the first supernatant is 1.5 g / L; and the oxygen flow rate of the second micro-nano bubble aeration is 8 kg / m³. 3 ·h; (3) Multi-media filtration and resin deep oil removal: The second supernatant is introduced into a multi-media filter and treated by multi-media filtration. The filtered second supernatant is then treated by resin oil removal resin column styrene-divinylphenyl skeleton adsorption resin to obtain effluent. The multi-media filtration process uses a first packing layer and a second packing layer. The first packing layer is made of granular activated carbon with a particle size of 2-4 mm, layer by layer, with a thickness of 500 mm. The second packing layer is made of quartz sand with a particle size of 2-4 mm, layer by layer, with a thickness of 800 mm. The flow rate of the resin degreasing process is 3 BV / h. The resin degreasing process involves filling a styrene-divinylphenyl skeleton adsorption resin into an ion exchange column, and then pumping the second supernatant after multi-media filtration through the resin-filled ion exchange column from top to bottom for adsorption, resulting in saturated resin and effluent. The diameter-to-height ratio of the ion exchange column is 1:

5. The saturated resin is regenerated with a desorbent and reused.

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