Ethylene glycol antimony production waste residue recovery method based on water washing and acid leaching method

Abstract

The invention discloses an ethylene glycol antimony production waste residue recovery method based on a water washing and acid leaching method, and relates to the technical field of chemical production waste residue treatment and resource recovery, and the method comprises the following steps: mixing waste residues with deionized water to obtain a first mixture, adding a surfactant, stirring, screening, and carrying out solid-liquid separation to obtain solid waste residues and a water washing solution, distilling water washing liquid to recover ethylene glycol; mixing the solid waste residues with acid liquor to obtain a second mixture, and performing solid-liquid separation after stirring reaction to obtain antimony-containing pickle liquor and acid leaching residues; neutralizing the antimony-containing pickle liquor to generate antimony trioxide precipitate, and separating and drying to obtain high-purity antimony trioxide; the acid leaching residues are washed and then circulated to the acid leaching step or innocent treatment according to the antimony content, and the waste liquid is recycled after acid liquid and water are recycled. By optimizing the washing and acid leaching processes, the recovery efficiency of antimony and ethylene glycol is remarkably improved; the waste liquid is recycled after being recovered and treated, so that the generation of wastes is reduced, and the environmental pollution risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical production waste residue treatment and resource recovery, and in particular to a method for recovering ethylene glycol antimony production waste residue based on water washing and acid leaching. Background Art

[0002] Antimony glycolate is a catalyst used in polyester production. Its production process involves the reaction of ethylene glycol and antimony trioxide in a reactor to produce liquid antimony glycolate, followed by filtration and impurity removal, crystallization and cooling, solid-liquid separation, and drying to obtain the finished product. During the production process, filtration and impurity removal and solid-liquid separation will produce waste residues containing antimony compounds, ethylene glycol residues, and other impurities. If these waste residues are discharged directly, it will not only waste antimony resources but also pollute the environment. Existing waste residue treatment technologies mostly use simple landfill or incineration, which has the disadvantages of low resource utilization and high environmental pollution risks. Therefore, it is of great significance to develop an efficient and environmentally friendly method for recycling antimony glycolate production waste residues. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a method for recovering waste residue from ethylene glycol antimony production based on water washing and acid leaching. The specific technical solution is as follows:

[0004] A method for recovering waste residue from ethylene glycol antimony production based on water washing and acid leaching, comprising the following steps:

[0005] a. The waste residue from the production of antimony glycol was mixed with deionized water to obtain a first mixture, a surfactant was added, and the mixture was stirred and sieved to obtain a solid waste residue and a washing liquid, and the washing liquid was distilled to recover ethylene glycol;

[0006] b. The solid waste was mixed with an acid solution to obtain a second mixture, and the reaction was stirred and then solid-liquid separation was performed to obtain an antimony-containing acid leaching solution and an acid leaching residue;

[0007] c. neutralizing the antimony acid-containing leaching solution to generate antimony trioxide precipitate, which is separated and dried to obtain high-purity antimony trioxide;

[0008] d. After washing the acid leaching residue, it is recycled to step b or treated harmlessly according to the antimony content, and the waste liquid is recycled after recovering the acid and water.

[0009] Preferably, in step a, the mass ratio of solid waste residue to deionized water is 1:(3-5), the stirring temperature is 50-60°C, the stirring time is 30-40 min, and the stirring speed is 200-300 rpm; the surfactant includes polyethylene glycol, and its addition amount is 0.3-0.5 wt%.

[0010] Preferably, in step a, the surfactant comprises a combination of polyethylene glycol and sodium lauryl sulfate, and the addition amounts thereof are 0.4 wt% and 0.1 wt%, respectively; the water washing liquid is subjected to vacuum distillation to recover ethylene glycol, the distillation pressure is 0.01 to 0.02 MPa, and the temperature is 180 to 190° C., and the remaining aqueous phase is treated with an ultrafiltration membrane and then recycled to the first mixture.

[0011] Preferably, in step b, the acid solution includes hydrochloric acid with a concentration of 1.5 to 2.5 mol / L, the solid-liquid ratio in the second mixture is 1:(6 to 8), the reaction temperature is 70 to 80°C, the stirring time is 1 to 2 hours, and the stirring speed is 100 to 150 rpm.

[0012] Preferably, the acid solution is a composite acid solution, which includes 1.8 mol / L hydrochloric acid, 0.1 mol / L citric acid and 0.05 mol / L oxalic acid, and the solid-liquid ratio in the second mixture is 1:(6-7); 0.01-0.02 wt% hydrogen peroxide is added as an oxidation aid during the reaction, and oxygen is introduced at a flow rate of 0.1-0.2 L / min.

[0013] Preferably, 0.01 wt% sodium nitrate is added as an oxidation aid during the reaction.

[0014] Preferably, a pretreatment step is further included before step a, and the pretreatment step includes: mixing the waste residue with deionized water, and adding 0.2-0.3wt% nano-alumina and 0.1-0.2wt% ammonium sulfate to form a third mixture, wherein the solid-liquid ratio of the third mixture is 1:(2-3), stirring at 55-65°C for 20-30min, and the stirring speed is 150-200rpm; after pretreatment, the material is subjected to solid-liquid separation to obtain pretreated waste residue and pretreated liquid, the pretreated waste residue is used as the ethylene glycol antimony production waste residue in step a, and the pretreated liquid is recycled to the first mixture after recovering nano-alumina and ammonium sulfate.

[0015] Preferably, in step c, the antimony acid leaching solution is added with a sodium hydroxide solution having a concentration of 1 to 2 mol / L, the pH is adjusted to 8.5 to 9.0, and the mixture is stirred at 55 to 65° C. for 20 to 30 minutes to generate an antimony trioxide precipitate; the precipitate is centrifuged and then vacuum dried at 80 to 90° C. and 0.01 to 0.02 MPa for 2 to 3 hours to obtain antimony trioxide with a purity of ≥98.5%.

[0016] Preferably, in step d, the acid leaching residue is washed with deionized water, the mass ratio of the acid leaching residue to deionized water is 1:(2-3), and the washing temperature is 45-55° C.; after washing, if the antimony content of the residue is greater than 5wt%, it is recycled to step b; if the antimony content is ≤5wt%, it is subjected to harmless treatment.

[0017] Preferably, the harmless treatment specifically includes: adding 0.5-1wt% lime to the acid leaching residue for neutralization treatment, adding deionized water at 40-50°C and stirring for 20-30 minutes to obtain a fourth mixture, wherein the solid-liquid ratio of the fourth mixture is 1:2; then separating the solid and liquid through a filter press to obtain a neutralized residue; and calcining the neutralized residue at 200-300°C for 1-1.5 hours to form a solid product, which is used as a building material additive.

[0018] The method for recovering waste residue from ethylene glycol antimony production based on water washing and acid leaching provided by the present invention has the following beneficial effects:

[0019] 1. By optimizing the water washing and acid leaching processes, the recovery efficiency of antimony and ethylene glycol is significantly improved;

[0020] 2. The acid leaching residue is dynamically recycled to the acid leaching step according to the antimony content, maximizing resource utilization and reducing production costs;

[0021] 3. Waste liquid is recycled and treated for reuse, reducing waste generation and minimizing the risk of environmental pollution. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0023] This embodiment provides a method for recovering waste residue from ethylene glycol antimony production based on water washing and acid leaching, comprising the following steps:

[0024] a. The ethylene glycol antimony production waste residue is mixed with deionized water to obtain a first mixture, a surfactant is added, and after stirring, solid waste residue and water washing liquid are obtained by screening and solid-liquid separation. The water washing liquid is distilled to recover ethylene glycol.

[0025] b. The solid waste residue is mixed with the acid solution to obtain a second mixture, which is stirred for reaction and then subjected to solid-liquid separation to obtain an antimony-containing acid leaching solution and an acid leaching residue.

[0026] c. Neutralize the antimony acid leaching solution to generate antimony trioxide precipitate, and obtain high-purity antimony trioxide through separation and drying.

[0027] d. After washing the acid leaching residue, it is recycled to step b or treated harmlessly according to the antimony content, and the waste liquid is recycled after recovering the acid and water.

[0028] Among them, step a can remove soluble organic matter in the waste residue and preliminarily separate large-particle impurities, creating conditions for subsequent acid leaching extraction; step b is used to extract antimony compounds from the solid waste residue to form a soluble antimony compound solution, laying the foundation for subsequent antimony recovery; step c can recover high-purity antimony trioxide from the antimony-containing acid leaching solution for reuse in ethylene glycol antimony production; step d realizes resource recycling and harmless treatment of waste residue, reducing production costs and environmental impact.

[0029] The method for recovering waste residue from ethylene glycol antimony production based on water washing and acid leaching provided in this embodiment has the following beneficial effects:

[0030] 1. By optimizing the water washing and acid leaching processes, the recovery efficiency of antimony and ethylene glycol can be significantly improved.

[0031] 2. The acid leaching residue is dynamically recycled to the acid leaching step according to the antimony content, maximizing resource utilization and reducing production costs.

[0032] 3. Waste liquid is recycled and treated for reuse, reducing waste generation and minimizing the risk of environmental pollution.

[0033] Furthermore, in step a, the mass ratio of solid waste to deionized water is 1:(3-5), the stirring temperature is 50-60°C, the stirring time is 30-40 minutes, and the stirring speed is 200-300 rpm. The surfactant includes polyethylene glycol, and the addition amount thereof is 0.3-0.5 wt%.

[0034] Furthermore, in step a, the surfactant comprises a combination of polyethylene glycol and sodium lauryl sulfate, with the added amounts being 0.4 wt % and 0.1 wt %, respectively. The ethylene glycol is recovered from the washing solution by vacuum distillation at a pressure of 0.01 to 0.02 MPa and a temperature of 180 to 190° C., and the remaining aqueous phase is treated with an ultrafiltration membrane and then recycled to the first mixture.

[0035] Furthermore, in step b, the acid solution includes hydrochloric acid with a concentration of 1.5 to 2.5 mol / L, the solid-liquid ratio in the second mixture is 1:(6 to 8), the reaction temperature is 70 to 80° C., the stirring time is 1 to 2 h, and the stirring speed is 100 to 150 rpm.

[0036] Furthermore, the acid solution is a composite acid solution comprising 1.8 mol / L hydrochloric acid, 0.1 mol / L citric acid, and 0.05 mol / L oxalic acid, with a solid-to-liquid ratio of 1:(6-7). During the reaction, 0.01-0.02 wt% hydrogen peroxide is added as an oxidizing agent, and oxygen is introduced at a flow rate of 0.1-0.2 L / min.

[0037] Furthermore, 0.01 wt% sodium nitrate was added as an oxidizing aid during the reaction.

[0038] Furthermore, a pretreatment step is included before step a, comprising: mixing the waste residue with deionized water, adding 0.2-0.3 wt% nano-alumina and 0.1-0.2 wt% ammonium sulfate to form a third mixture, wherein the solid-liquid ratio of the third mixture is 1:(2-3), and stirring at 55-65° C. for 20-30 minutes at a stirring speed of 150-200 rpm. After pretreatment, the material is subjected to solid-liquid separation to obtain pretreatment waste residue and pretreatment liquid. The pretreatment waste residue is used as the waste residue for the production of ethylene glycol antimony in step a, and the pretreatment liquid is recycled to the first mixture after recovering the nano-alumina and ammonium sulfate.

[0039] Among them, nano-alumina and ammonium sulfate can change the crystal structure and surface energy of antimony trioxide, thereby improving the efficiency of subsequent acid leaching; nano-alumina can be replaced by nano-titanium dioxide or silicate, and ammonium sulfate can be replaced by ammonium chloride; the pretreatment step can be combined with mechanical grinding or high-temperature pre-calcination (100-150°C) to further optimize the solubility of the waste residue.

[0040] Furthermore, in step c, the antimony acid-containing leaching solution is adjusted to a pH of 8.5 to 9.0 by adding a sodium hydroxide solution having a concentration of 1 to 2 mol / L, and stirred at 55 to 65° C. for 20 to 30 minutes to generate an antimony trioxide precipitate. The precipitate is centrifuged and then vacuum-dried at 80 to 90° C. and 0.01 to 0.02 MPa for 2 to 3 hours to obtain antimony trioxide with a purity of ≥98.5%.

[0041] Furthermore, in step d, the acid leaching residue is washed with deionized water, and the mass ratio of the acid leaching residue to the deionized water is 1:

[0042] (2-3), the washing temperature is 45-55°C. After washing, if the antimony content of the residue is greater than 5wt%, it is recycled to step b. If the antimony content is ≤5wt%, it is subjected to harmless treatment.

[0043] Furthermore, the harmless treatment specifically includes neutralizing the acid leaching residue with 0.5-1 wt% lime, adding deionized water at 40-50°C and stirring for 20-30 minutes to produce a fourth mixture with a solid-liquid ratio of 1:2. The fourth mixture is then subjected to solid-liquid separation using a filter press to produce a neutralized residue. The neutralized residue is then calcined at 200-300°C for 1-1.5 hours to form a solid product, which is used as a building material additive.

[0044] Specific examples are provided below. The provided examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0045] Example 1

[0046] 100 kg of ethylene glycol antimony production waste residue and 400 kg of deionized water were added to a stirred tank, heated to 55°C, stirred at 250 rpm for 40 minutes. 0.4 kg of PEG-400 was added and stirred continuously. The mixture was filtered through an 80-mesh sieve, and approximately 2.7 kg of large impurities were found on the sieve. The undersize fraction was centrifuged at 3500 rpm for 6 minutes to produce 89.2 kg of solid waste residue and 408.5 L of water wash solution. The water wash solution was passed into a vacuum distillation tower (pressure 0.015 MPa, temperature 185°C) to recover 10.8 kg of ethylene glycol. The remaining aqueous phase, approximately 397.3 L, was treated with an ultrafiltration membrane (pore size 0.01 μm) and recycled to the next batch of water washes.

[0047] The solid waste residue and hydrochloric acid (2.0 mol·L -1 ) was added to a reactor, heated to 75°C, stirred at 120 rpm, and reacted for 1.5 hours. After the reaction was complete, the mixture was separated using a plate and frame filter press (pressure 0.6 MPa) to obtain 610.8 L of antimony acid leaching solution and 6.3 kg of acid leaching residue.

[0048] The antimony acid leaching solution was passed into the neutralization tank and sodium hydroxide solution (1.5 mol·L -1 ) was added to approximately 92.4 L of a 5% ethanol solution, the pH was adjusted to 8.7, the temperature was maintained at 60°C, and stirring was carried out for 25 minutes (100 rpm) to form an antimony trioxide precipitate. The precipitate was separated by centrifuge (4000 rpm, 8 minutes) to obtain 13.9 kg of crude antimony trioxide. The crude product was dried in a vacuum drying oven (85°C, 0.015 MPa) for 2.5 hours to obtain 12.4 kg of high-purity antimony trioxide.

[0049] The acid leaching residue was added to a washing tank, 18.9 kg of deionized water was added, and the mixture was stirred at 50 ° C for 20 minutes (150 rpm). XRF analysis showed that the antimony content of the residue was 4.8 wt%, and the residue was harmlessly treated. The residue was mixed with 0.05 kg of lime, added with deionized water, stirred at 45 ° C for 25 minutes, and separated by a filter press (pressure 0.5 MPa) to obtain 5.7 kg of neutralized residue. The neutralized residue was roasted in a roasting furnace at 250 ° C for 1.2 hours to obtain 5.4 kg of stable solid product, which was used as a building material additive. About 695.2 L of neutralized waste liquid was recovered by a membrane distillation system (60 ° C, 0.05 MPa) to recover 532.7 L of hydrochloric acid and circulated to the acid leaching step. The remaining aqueous phase 159.3 L was circulated to the water washing step.

[0050] In this example, the ethylene glycol recovery rate was calculated by weighing the mass of ethylene glycol recovered by vacuum distillation; the purity of antimony trioxide was determined by chemical titration; and the antimony recovery rate was calculated by measuring the antimony content of the antimony trioxide product and the initial antimony content of the waste residue.

[0051] The test data is shown in the following table:

[0052]

[0053] Example 2

[0054] 100 kg of ethylene glycol antimony production waste residue and 400 kg of deionized water were added to a stirred tank, heated to 55°C, stirred at 250 rpm for 40 minutes. 0.4 kg of PEG-400 and 0.1 kg of SDS were added, and stirring continued. The mixture was filtered through an 80-mesh sieve, and approximately 2.6 kg of large impurities were found on the sieve. The undersize material was centrifuged at 3500 rpm for 6 minutes to produce 88.7 kg of solid waste residue and 409.2 L of water wash solution. The water wash solution was passed into a vacuum distillation tower (pressure 0.012 MPa, temperature 187°C) to recover 11.2 kg of ethylene glycol. The remaining aqueous phase, approximately 397.8 L, was treated with an ultrafiltration membrane (pore size 0.01 μm) and recycled to the next batch of water washes.

[0055] The solid waste and composite acid solution (532.2 L of 1.8 mol / L hydrochloric acid, 29.6 L of 0.1 mol / L citric acid, and 14.8 L of 0.05 mol / L oxalic acid) were added to the reactor, heated to 75°C, stirred at 120 rpm, and oxygen was introduced (0.15 L min -1 ), with a reaction time of 1.5 h. 0.059 kg of hydrogen peroxide (30 wt%) was added, and the reaction was continued. After the reaction was completed, the mixture was separated by a plate and frame filter press (pressure 0.6 MPa) to obtain 566.4 L of antimony-containing acid leaching solution and 5.8 kg of acid leaching residue.

[0056] The acid leaching solution was passed into the neutralization tank and sodium hydroxide solution (1.5 mol·L -1 ) was added to approximately 85.7 L of ethanol, the pH was adjusted to 8.8, the temperature was maintained at 60°C, and stirring was carried out for 25 minutes (100 rpm) to form an antimony trioxide precipitate. The precipitate was separated by centrifuge (4000 rpm, 8 minutes) to obtain 14.2 kg of crude antimony trioxide. The crude product was dried in a vacuum drying oven (85°C, 0.015 MPa) for 2.5 hours to obtain 12.7 kg of high-purity antimony trioxide.

[0057] The acid leaching residue was added to a washing tank, 17.4 kg of deionized water was added, and the mixture was stirred at 50 ° C for 20 minutes (150 rpm). XRF analysis showed that the antimony content of the residue was 4.6 wt%, and the residue was harmlessly treated. The residue was mixed with 0.046 kg of lime, added with deionized water, stirred at 45 ° C for 25 minutes, and separated by a filter press (pressure 0.5 MPa) to obtain 5.3 kg of neutralized residue. The neutralized residue was roasted in a roasting furnace at 250 ° C for 1.2 hours to obtain 5.1 kg of stable solid product, which was used as a building material additive. About 644.6 L of neutralized waste liquid was recovered by a membrane distillation system (60 ° C, 0.05 MPa) to recover 527.2 L of acid solution and circulated to the acid leaching step. The remaining aqueous phase 147.8 L was circulated to the water washing step.

[0058] In this example, the ethylene glycol recovery rate was calculated by weighing the mass of ethylene glycol recovered by vacuum distillation; the purity of antimony trioxide was determined by chemical titration; and the antimony recovery rate was calculated by measuring the antimony content of the antimony trioxide product and the initial antimony content of the waste residue.

[0059] The test data is shown in the following table:

[0060]

[0061] Example 3

[0062] 100 kg of ethylene glycol antimony production waste residue and 400 kg of deionized water were added to a stirred tank, heated to 55°C, stirred at 250 rpm for 40 minutes. 0.4 kg of PEG-400 and 0.1 kg of SDS were added, and stirring continued. The mixture was filtered through an 80-mesh sieve, and approximately 2.5 kg of large impurities were found on the sieve. The undersize fraction was centrifuged at 3500 rpm for 6 minutes to produce 88.9 kg of solid waste residue and 408.7 L of water wash solution. The water wash solution was passed into a vacuum distillation tower (pressure 0.012 MPa, temperature 187°C) to recover 11.1 kg of ethylene glycol. The remaining aqueous phase, approximately 397.4 L, was treated with an ultrafiltration membrane (pore size 0.01 μm) and recycled to the next water wash.

[0063] The solid waste and composite acid solution (533.4 L of 1.8 mol / L hydrochloric acid, 29.6 L of 0.1 mol / L citric acid, and 14.8 L of 0.05 mol / L oxalic acid) were added to the reactor, heated to 75°C, stirred at 120 rpm, and oxygen was introduced (0.15 L min -1 ), 0.059 kg of hydrogen peroxide (30 wt%) and 0.039 kg of sodium nitrate were added, and the reaction time was 1.0 h. After the reaction was completed, the mixture was separated by a plate and frame filter press (pressure 0.6 MPa) to obtain 568.2 L of antimony-containing acid leaching solution and 5.6 kg of acid leaching residue.

[0064] The acid leaching solution was passed into the neutralization tank and sodium hydroxide solution (1.5 mol·L -1 ) was added to approximately 86.1 L of a 5% ethanol solution, the pH was adjusted to 8.8, the temperature was maintained at 60°C, and stirring was carried out for 25 minutes (100 rpm) to form an antimony trioxide precipitate. The precipitate was separated by centrifuge (4000 rpm, 8 minutes) to obtain 14.4 kg of crude antimony trioxide. The crude product was dried in a vacuum drying oven (85°C, 0.015 MPa) for 2.5 hours to obtain 12.9 kg of high-purity antimony trioxide.

[0065] The acid leaching residue was added to a washing tank, 16.8 kg of deionized water was added, and the mixture was stirred at 50 ° C for 20 minutes (150 rpm). XRF analysis showed that the antimony content of the residue was 4.4 wt%, and the residue was harmlessly treated. The residue was mixed with 0.045 kg of lime, deionized water was added, stirred at 45 ° C for 25 minutes, and separated by a filter press (pressure 0.5 MPa) to obtain 5.2 kg of neutralized residue. The neutralized residue was roasted in a roasting furnace at 250 ° C for 1.2 hours to obtain 5.0 kg of stable solid product, which was used as a building material additive. About 646.7 L of neutralized waste liquid was recovered by a membrane distillation system (60 ° C, 0.05 MPa) to recover 529.3 L of acid solution and circulated to the acid leaching step. The remaining aqueous phase 148.2 L was circulated to the water washing step.

[0066] In this example, the ethylene glycol recovery rate was calculated by weighing the mass of ethylene glycol recovered by vacuum distillation; the purity of antimony trioxide was determined by chemical titration; and the antimony recovery rate was calculated by measuring the antimony content of the antimony trioxide product and the initial antimony content of the waste residue.

[0067] The test data is shown in the following table:

[0068]

[0069] Example 4

[0070] 100 kg of ethylene glycol antimony production waste residue, 200 kg of deionized water, 0.25 kg of nano-alumina (average particle size 25 nm), and 0.15 kg of ammonium sulfate were added to a pretreatment tank and heated to 60°C with a stirring rate of 180 rpm for 25 minutes. The mixture was separated using a filter press (pressure 0.5 MPa) to obtain 95.6 kg of modified waste residue and 203.7 L of pretreatment liquid. The pretreatment liquid was then passed through a magnetic separator and membrane filter to recover 0.23 kg of nano-alumina and 0.14 kg of ammonium sulfate, which were then recycled to the next batch of pretreatment.

[0071] The modified waste residue and 382.4 kg of deionized water were added to a stirring tank, heated to 55°C, stirred at 250 rpm, and stirred for 40 minutes. 0.382 kg of PEG-400 and 0.096 kg of SDS were added, and stirring continued. The mixture was filtered through an 80-mesh sieve, and approximately 2.3 kg of large impurities were found on the sieve. The undersize material was centrifuged at 3500 rpm for 6 minutes to produce 85.3 kg of solid waste residue and 390.8 L of water wash solution. The water wash solution was passed into a vacuum distillation tower (pressure 0.012 MPa, temperature 187°C) to recover 11.3 kg of ethylene glycol. The remaining aqueous phase, approximately 379.2 L, was treated with an ultrafiltration membrane (pore size 0.01 μm) and recycled to the next batch of water washes.

[0072] The solid waste and composite acid solution (511.8 L of 1.8 mol / L hydrochloric acid, 28.4 L of 0.1 mol / L citric acid, and 14.2 L of 0.05 mol / L oxalic acid) were added to the reactor, heated to 75°C, stirred at 120 rpm, and oxygen was introduced (0.15 L min -1 ), 0.057 kg of hydrogen peroxide (30 wt%) and 0.038 kg of sodium nitrate were added, and the reaction time was 1.0 h. After the reaction was completed, the mixture was separated by a plate and frame filter press (pressure 0.6 MPa) to obtain 544.6 L of antimony-containing acid leaching solution and 5.4 kg of acid leaching residue.

[0073] The acid leaching solution was passed into the neutralization tank and sodium hydroxide solution (1.5 mol·L -1 ) was added to approximately 82.5 L of a 5% ethanol solution, the pH was adjusted to 8.8, the temperature was maintained at 60°C, and stirring was carried out for 25 minutes (100 rpm) to form an antimony trioxide precipitate. The precipitate was separated by centrifuge (4000 rpm, 8 minutes) to obtain 14.6 kg of crude antimony trioxide. The crude product was dried in a vacuum drying oven (85°C, 0.015 MPa) for 2.5 hours to obtain 13.1 kg of high-purity antimony trioxide.

[0074] The acid leaching residue was added to a washing tank, 16.2 kg of deionized water was added, and the mixture was stirred at 50 ° C for 20 minutes (150 rpm). XRF analysis showed that the antimony content of the residue was 4.3 wt%, and the residue was harmlessly treated. The residue was mixed with 0.043 kg of lime, added with deionized water, stirred at 45 ° C for 25 minutes, and separated by a filter press (pressure 0.5 MPa) to obtain 5.0 kg of neutralized residue. The neutralized residue was roasted in a roasting furnace at 250 ° C for 1.2 hours to obtain 4.8 kg of stable solid product, which was used as a building material additive. About 620.4 L of neutralized waste liquid was recovered by a membrane distillation system (60 ° C, 0.05 MPa) to recover 507.6 L of acid solution and circulated to the acid leaching step. The remaining aqueous phase 142.7 L was circulated to the water washing step.

[0075] In this example, the ethylene glycol recovery rate was calculated by weighing the mass of ethylene glycol recovered by vacuum distillation; the purity of antimony trioxide was determined by chemical titration; and the antimony recovery rate was calculated by measuring the antimony content of the antimony trioxide product and the initial antimony content of the waste residue.

[0076] The test data is shown in the following table:

[0077]

[0078] Comparative Example

[0079] 100 kg of waste residue from ethylene glycol antimony production and 400 kg of deionized water were added to a stirred tank, heated to 50°C, stirred at 200 rpm for 45 minutes. The mixture was filtered through an 80-mesh sieve, and the oversize fraction contained approximately 3.1 kg of large impurities. The undersize fraction was centrifuged at 3000 rpm for 8 minutes to yield 90.3 kg of solid waste residue and 406.2 L of water wash. The water wash was passed into a distillation column (pressure 0.012 MPa, temperature 187°C) to recover 9.8 kg of ethylene glycol.

[0080] The solid waste residue and hydrochloric acid (2.0 mol·L -1 ) was added to a reactor, heated to 70°C, stirred at 100 rpm, and reacted for 2.0 h. After the reaction was complete, the mixture was separated using a plate and frame filter press (pressure 0.5 MPa) to obtain 618.4 L of antimony acid leaching solution and 7.2 kg of acid leaching residue.

[0081] The acid leaching solution was passed into the neutralization tank and sodium hydroxide solution (1.5 mol·L -1 ) 93.7 L, adjusted the pH to 8.5, maintained the temperature at 55°C, and stirred for 30 minutes (100 rpm) to form an antimony trioxide precipitate. The precipitate was separated by centrifuge (4000 rpm, 10 minutes) to obtain 13.6 kg of crude antimony trioxide. The crude product was dried in a drying oven (85°C, 0.015 MPa) for 2.5 hours to obtain 12.1 kg of antimony trioxide.

[0082] The acid leaching residue was placed in a washing tank, and 21.6 kg of deionized water was added. The mixture was stirred at 45°C for 30 minutes (150 rpm). The residue was mixed with 0.072 kg of lime, deionized water was added, and the mixture was stirred at 40°C for 30 minutes. The mixture was separated by a filter press (pressure 0.5 MPa) to obtain 6.8 kg of neutralized residue. The neutralized residue was calcined in a calciner at 200°C for 1.5 hours to obtain 6.5 kg of solid product, which was used as a building material additive.

[0083] In this comparative example, the ethylene glycol recovery rate was calculated by weighing the mass of ethylene glycol recovered by vacuum distillation; the purity of antimony trioxide was determined by chemical titration; and the antimony recovery rate was calculated by measuring the antimony content of the antimony trioxide product and the initial antimony content of the waste residue.

[0084] The test data is shown in the following table:

[0085]

[0086] It can be seen that the ethylene glycol antimony production waste residue recovery method provided in Examples 1 to 4 significantly improves the recovery efficiency of ethylene glycol and antimony compared to the ordinary recovery method, and reduces the residual antimony content and solid waste amount. It is an efficient and environmentally friendly recovery method.

[0087] The principles and implementation methods of the present invention are described herein using specific examples. The description of the above embodiments is only intended to help understand the method and core ideas of the present invention. The above are only preferred implementation methods of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, and all of these should fall within the scope of protection of the present invention.

Claims

1. A method for recovering waste residue from ethylene glycol antimony production based on water washing and acid leaching, characterized in that: The steps include: a) mixing waste residue from ethylene glycol antimony production with deionized water to obtain a first mixture, adding a surfactant, stirring, and then screening and solid-liquid separation to obtain solid waste residue and a water washing liquid, and distilling the water washing liquid to recover ethylene glycol; b) mixing the solid waste with the acid solution to obtain a second mixture, stirring the mixture for reaction, and then performing solid-liquid separation to obtain an antimony-containing acid leaching solution and an acid leaching residue; c) neutralizing the antimony acid leaching solution to generate antimony trioxide precipitate, and obtaining high-purity antimony trioxide through separation and drying; d) washing the acid leaching residue and recycling it to step b) or performing harmless treatment according to the antimony content, and recycling the waste liquid for acid and water.

2. The method according to claim 1, characterized in that In step a), the mass ratio of solid waste to deionized water is 1:(3-5), the stirring temperature is 50-60° C., the stirring time is 30-40 min, and the stirring speed is 200-300 rpm; the surfactant includes polyethylene glycol, and the addition amount thereof is 0.3-0.5 wt %.

3. The method according to claim 2, characterized in that In step a), the surfactant comprises a combination of polyethylene glycol and sodium lauryl sulfate, with the added amounts being 0.4 wt% and 0.1 wt%, respectively; the water wash solution is subjected to vacuum distillation to recover ethylene glycol at a distillation pressure of 0.01 to 0.02 MPa and a temperature of 180 to 190° C., and the remaining aqueous phase is treated with an ultrafiltration membrane and then recycled to the first mixture.

4. The method according to claim 1, wherein In step b), the acid solution includes hydrochloric acid with a concentration of 1.5 to 2.5 mol / L, the solid-liquid ratio in the second mixture is 1:(6 to 8), the reaction temperature is 70 to 80° C., the stirring time is 1 to 2 h, and the stirring speed is 100 to 150 rpm.

5. The method according to claim 4, characterized in that The acid solution is a composite acid solution, which includes 1.8 mol / L hydrochloric acid, 0.1 mol / L citric acid and 0.05 mol / L oxalic acid, and the solid-liquid ratio in the second mixture is 1:(6-7); 0.01-0.02 wt% hydrogen peroxide is added as an oxidation aid during the reaction, and oxygen is introduced at a flow rate of 0.1-0.2 L / min.

6. The method according to claim 5, characterized in that During the reaction, 0.01 wt% sodium nitrate was added as an oxidation aid.

7. The method according to claim 1, characterized in that The method further includes a pretreatment step before step a), wherein the pretreatment step comprises: mixing waste residue with deionized water, adding 0.2-0.3 wt% of nano-alumina and 0.1-0.2 wt% of ammonium sulfate to form a third mixture, wherein the solid-liquid ratio of the third mixture is 1:(2-3), and stirring the mixture at 55-65° C. for 20-30 minutes at a stirring speed of 150-200 rpm; performing solid-liquid separation on the pretreated material to obtain pretreated waste residue and pretreated liquid, wherein the pretreated waste residue is used as the ethylene glycol antimony production waste residue in step a), and the pretreated liquid is recycled to the first mixture after recovering nano-alumina and ammonium sulfate.

8. The method according to claim 1, characterized in that In step c), the antimony acid leaching solution is added with a sodium hydroxide solution having a concentration of 1 to 2 mol / L, the pH value is adjusted to 8.5 to 9.0, and the solution is stirred at 55 to 65° C. for 20 to 30 minutes to generate an antimony trioxide precipitate; the precipitate is centrifuged and then vacuum dried at 80 to 90° C. and 0.01 to 0.02 MPa for 2 to 3 hours to obtain antimony trioxide with a purity of ≥98.5%.

9. The method according to claim 1, characterized in that In step d), the acid leaching residue is washed with deionized water, the mass ratio of the acid leaching residue to deionized water is 1:(2-3), and the washing temperature is 45-55° C. After washing, if the antimony content of the residue is greater than 5wt%, the residue is recycled to step b); if the antimony content is ≤5wt%, the residue is subjected to harmless treatment.

10. The method according to claim 1 or 9, characterized in that The harmless treatment specifically includes: adding 0.5-1wt% of lime to the acid leaching residue for neutralization treatment, adding deionized water at 40-50°C and stirring for 20-30 minutes to obtain a fourth mixture, wherein the solid-liquid ratio of the fourth mixture is 1:2; then separating the solid and liquid through a filter press to obtain a neutralized residue; and roasting the neutralized residue at 200-300°C for 1-1.5 hours to form a solid product, which is used as a building material additive.

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