Recovery method and recovery device for aluminum material electrochemical polishing waste liquid

Abstract

The invention relates to the technical field of resource recovery, in particular to a recovery method and a recovery device for aluminum material electrochemical polishing waste liquid. The recycling method comprises the following steps that the aluminum material electrochemical polishing waste liquid is diluted till to-be-treated feed liquid with the aluminum ion concentration not higher than 30 g / L is obtained; respectively and reversely introducing the feed liquid to be treated and water from two sides of an anion exchange membrane, controlling the flow ratio of the feed liquid to be treated to the water to be 1: (1-5), and collecting the liquid flowing out from one side of the water to obtain the recycled acid. Before diffusion dialysis treatment is conducted on the aluminum material electrochemical polishing waste liquid, the aluminum material electrochemical polishing waste liquid is diluted till the concentration of aluminum ions in the to-be-treated feed liquid is not higher than 30 g / L. After dilution treatment, the flow ratio of the feed liquid to be treated to water is controlled to be 1: (1-5), so that the recovery rate of phosphoric acid can be increased, the rejection rate of metal ions including aluminum ions can be increased, and even the rejection rate of the aluminum ions can reach 100%.

Description

Technical Field

[0001] The present application relates to the technical field of resource recovery, and in particular to a method and a device for recovering waste liquid from electrochemical polishing of aluminum materials. Background Art

[0002] Products made of aluminum as raw materials can be seen everywhere in people's daily lives. Electrochemical polishing is a common surface treatment technology in aluminum processing. However, a large amount of waste acid is generated during the electrochemical polishing process. If the waste acid is not treated and directly discharged into the sewer or water body, it will corrode pipes and structures, change the pH value of the water body, destroy the natural buffer, inhibit the growth of microorganisms, and be detrimental to water purification. At the same time, the acid will dissolve minerals in the soil or sediment, increase the concentration of inorganic salts in the water and the hardness of the water, and the impact on groundwater is particularly significant.

[0003] Most of the existing waste acid treatment methods are chemical neutralization precipitation and immersion combustion. Chemical neutralization precipitation is the most commonly used method for treating acidic wastewater. By adding alkaline substances (CaO) to the wastewater and increasing the pH of the system, the metal substances in the wastewater are removed by hydroxide precipitation. The immersion combustion method is a new type of combustion heating technology. It is to mix the gas and air fully, send them into the combustion chamber for complete combustion, form high-temperature flue gas, and then spray the high-temperature flue gas into the waste acid to evaporate the water, so as to achieve the purpose of recovering the waste acid and precipitating crystal salt. The chemical neutralization precipitation method and the immersion combustion method have their own advantages and disadvantages in treating waste acid. Although the chemical neutralization precipitation method has a simple process, the free acid in the waste acid cannot be recycled, and the neutralization process requires a large amount of alkali, resulting in a large waste of resources. Although the immersion combustion method has a high resource recovery rate, the initial investment and operating costs are huge. In addition, the submerged combustion method has very high requirements for fuel. The sulfur content must be very low, otherwise the submerged combustion device will be corroded by the generated SO2. At the same time, there must be no carbon particles and other impurities in the fuel gas, otherwise it will pollute the water body and affect its use. At the same time, the submerged combustion device must be equipped with a fan that can overcome the water pressure. At the same time, the non-condensable gas in the flue gas will reduce the heat transfer coefficient of the condenser and cause a large amount of heat loss.

[0004] Diffusion dialysis technology is a membrane separation technology that can be used to recycle waste acid in many industrial fields, such as the steel industry, titanium dioxide industry, and hydrometallurgical copper industry. However, the waste acid produced by electrochemical polishing of aluminum contains aluminum ions and phosphoric acid. The traditional diffusion dialysis method has a low recovery rate for phosphoric acid and a low retention rate for aluminum ions. Summary of the invention

[0005] Based on this, the first aspect of the present application provides a method for recovering waste liquid from electrochemical polishing of aluminum materials, the purpose of which is to improve the recovery rate of phosphoric acid in the waste liquid generated by electrochemical polishing of aluminum materials by the diffusion dialysis method and to improve the interception rate of aluminum ions. The technical scheme is as follows:

[0006] A method for recovering aluminum electrochemical polishing waste liquid comprises the following steps:

[0007] The aluminum electrochemical polishing waste liquid is diluted to obtain Al 3+ The concentration of the treated liquid is not higher than 30g / L;

[0008] The treated liquid and water are respectively introduced into both sides of the anion exchange membrane in reverse direction, and the flow ratio of the treated liquid and water is controlled to be 1: (1-5), and the liquid flowing out of the water side is collected to obtain the recovered acid.

[0009] The second aspect of the present application provides a recovery device for aluminum electrochemical polishing waste liquid used in the above-mentioned recovery method, and its technical solution is as follows:

[0010] A device for recovering waste liquid from electrochemical polishing of aluminum materials comprises a waste liquid tank, a dilution tank and a diffusion dialysis device, wherein the waste liquid tank is connected to the dilution tank, and the dilution tank is connected to the diffusion dialysis device.

[0011] Compared with the traditional solution, this application has the following beneficial effects:

[0012] In the present invention, the aluminum electrochemical polishing waste liquid is diluted to the Al content in the treated liquid before the diffusion dialysis treatment. 3+ The concentration is not higher than 30g / L. After dilution treatment, by controlling the flow ratio of the treated liquid and water to 1: (1~5), the recovery rate of phosphoric acid can be improved, including Al 3+ The interception rate of metal ions including Al 3+ The interception rate is 100%. In addition, the above recovery method does not introduce new reagents and does not have new risks, and can simultaneously meet the goals of rationally utilizing resources, protecting the environment and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0014] Figure 1 A schematic flow chart of a method for recycling waste liquid from electrochemical polishing of aluminum materials according to an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of the diffusion dialysis principle of a method for recovering waste liquid from electrochemical polishing of aluminum materials according to an embodiment of the present invention;

[0016] Figure 3 It is a schematic structural diagram of an aluminum electrochemical polishing waste liquid recovery device according to one embodiment. DETAILED DESCRIPTION

[0017] The present application will be further described in detail below in conjunction with specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly understood.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0019] the term

[0020] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0021] In this application, "optionally", "optional" and "optional" refer to optional, that is, to any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0022] In this application, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0023] In the present application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the optional numerical distribution within the above numerical interval is deemed to be continuous and includes the two numerical endpoints of the numerical range (i.e., the minimum value and the maximum value), and every numerical value between the two numerical endpoints.

[0024] In this application, when it comes to percentage concentration, unless otherwise specified, it refers to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of the component.

[0025] The present application provides a first aspect of a method for recovering aluminum electrochemical polishing waste liquid. In one embodiment, see Figure 1 The method for recovering the waste liquid from electrochemical polishing of aluminum materials comprises the following steps:

[0026] S10, diluting the aluminum electrochemical polishing waste liquid to obtain Al 3+ The concentration of the treated liquid is not higher than 30g / L.

[0027] The aluminum electrochemical polishing waste liquid refers to the waste liquid generated when the aluminum material is subjected to chemical polishing surface treatment, wherein the aluminum material can be aluminum or aluminum alloy. The aluminum electrochemical polishing waste liquid includes the following components: H2SO4, H3PO4 and Al 3+ .

[0028] In some examples, before diluting the aluminum electrochemical polishing waste liquid, the following steps are also included: filtering to remove solid impurities in the aluminum electrochemical polishing waste liquid. The aluminum electrochemical polishing waste liquid is first filtered to remove solid impurities to meet the quality requirements of the subsequent diffusion dialysis equipment. In this embodiment, the aluminum electrochemical polishing waste liquid is first passed through a bag filter and a security filter to remove large-particle suspended solids, and then passed through a microfiltration system with a pore size of 1 μm to remove small-particle solid impurities. The filtered aluminum electrochemical polishing waste liquid is diluted.

[0029] It can be understood that, in addition to filtering and removing solid impurities in the aluminum electrochemical polishing waste liquid before diluting the aluminum electrochemical polishing waste liquid, in other examples, after diluting the aluminum electrochemical polishing waste liquid, the following steps are also included: filtering and removing solid impurities in the dilution liquid. For example, the dilution liquid is first passed through a bag filter and a security filter to remove large-sized solid suspended matter, and then passed through a microfiltration system with a pore size of 1 μm to remove small-sized solid impurities to obtain the liquid to be treated.

[0030] During the dilution treatment, the aluminum ion concentration in the treated liquid can be controlled by controlling the volume ratio of the aluminum electrochemical polishing waste liquid to the dilution water. Optionally, the volume ratio of the aluminum electrochemical polishing waste liquid to the dilution water is (1-4):1. For example, the volume ratio is 1:1, 2:1, 3:1, 4:1. In this embodiment, it is verified by experiments that before the diffusion dialysis treatment, the aluminum ion concentration in the treated liquid is controlled by controlling the volume ratio of the aluminum electrochemical polishing waste liquid to the dilution water. 3+ The content of is the control target. When it is within the range of 30g / L, during the diffusion dialysis treatment, not only is the retention rate of aluminum ions high, but it also increases the concentration of phosphoric acid in the recovered acid, which is beneficial to improving the recovery rate of phosphoric acid.

[0031] After dilution, stir thoroughly, cool to about 40°C and set aside for later use.

[0032] S20, respectively, countercurrently introducing the feed liquid to be treated and water on both sides of the anion exchange membrane, and controlling the flow ratio of the feed liquid to be treated and water to be 1: (1-5), collecting the liquid flowing out of the water side to obtain recovered acid.

[0033] After the dilution treatment, the treated liquid is subjected to diffusion dialysis treatment. The diffusion dialysis treatment can be carried out in a diffusion dialysis device. The diffusion dialysis device includes a plurality of structural units, wherein each structural unit includes an anion exchange membrane. The anion exchange membrane separates the structural unit into a dialysis chamber and a diffusion chamber. The treated liquid can be introduced into the dialysis chamber, and water can be introduced into the diffusion chamber. The ion concentration of the treated liquid in the dialysis chamber is much higher than the concentration of the water in the diffusion chamber. Due to the existence of the concentration gradient, the ions in the treated liquid in the dialysis chamber tend to penetrate from the anion exchange membrane to the water in the diffusion chamber. At the same time, the anion exchange membrane has the characteristic of selective permeability, which can pass through specific ions and intercept other ions. The recovered acid is obtained by the above method. In this embodiment, please refer to Figure 2 The treated liquid 2 and water 3 are introduced into the two sides of the anion exchange membrane 1 in reverse order. The metal ions M in the treated liquid n+ is retained by anion exchange membrane 1, while H + and acid ion A n- The water is selectively permeated by the anion exchange membrane 1, and the liquid flowing out of the water side is collected to obtain a recovered acid with less metal ion content and more acid content.

[0034] In this embodiment, it is verified by experiments that during the diffusion dialysis process, the flow ratio of the liquid to be treated and water is controlled to be 1: (1-5). For example, the flow ratio of the liquid to be treated and water is controlled to be 1: 1, 1: 2, 1: 3, 1: 4, 1: 5. At this time, it is beneficial to intercept more metal ions M n+ , and choose to use more H + and acid ion A n- , especially phosphate ions, the above ratio is conducive to improving the permeability of phosphate ions, and within the above ratio range, as the flow rate of water increases, the permeability of phosphate ions first increases and then decreases. Preferably, the flow rate ratio of the treated liquid to water is controlled to be 1: (2~3).

[0035] Optionally, the flow rate of the feed liquid to be treated is 45 L / h to 200 L / h. For example, the flow rate of the feed liquid to be treated is 45 L / h, 80 L / h, 90 L / h, 100 L / h, 150 L / h, or 200 L / h.

[0036] Optionally, the water flow rate is 160 L / h to 320 L / h. For example, the water flow rate is 160 L / h, 220 L / h, 230 L / h, 260 L / h, 300 L / h, 320 L / h.

[0037] Optionally, the material of the anion exchange membrane includes a polyether polymer compound containing phenyl groups.

[0038] It can be understood that, in addition to the anion exchange membrane, the diffusion dialysis equipment also includes components such as a liquid distribution plate, a reinforcement plate and a liquid flow plate frame. The above components can be structural components commonly understood by those skilled in the art and are not limited in this application.

[0039] S30, evaporating and concentrating the recovered acid.

[0040] By evaporation and concentration, the excess water in the recovered acid can be concentrated to concentrate the active ingredients in the recovered acid, so as to meet the target parameters of the use under different requirements for the concentration of the active ingredients. It is understandable that the evaporation and concentration can be carried out in an evaporation device, which can be a conventional device in the art. It is understandable that after the recovered acid is evaporated and concentrated, a cooling step is also included.

[0041] Optionally, the temperature of evaporation and concentration is 100° C. to 1000° C. The temperature and time of evaporation and concentration can be adjusted according to the required concentration of the target component, so that the recovered acid after evaporation and concentration can be directly used in the production line after cooling.

[0042] S40, adding acid solution to the recovered acid after evaporation and concentration, and recycling it into the electrolyte for electrochemical polishing of aluminum materials.

[0043] Optionally, the sulfuric acid content in the recovered acid after evaporation and concentration can reach 600g / L~750g / L, the phosphoric acid content can reach 500g / L~650g / L, and the solution density can reach 1.60g / mL~1.75g / mL. Acid solution can be added or not added according to actual conditions and reused in the electrolyte of aluminum electrochemical polishing.

[0044] In the above embodiment, the aluminum electrochemical polishing waste liquid is diluted to the Al content in the to-be-treated liquid before the diffusion dialysis treatment. 3+ The concentration is not higher than 30g / L. After dilution treatment, by controlling the flow ratio of the treated liquid and water to 1: (1~5), the recovery rate of phosphoric acid can be improved, including Al 3+ The interception rate of metal ions including Al 3+ The interception rate is 100%. In addition, the above recovery method does not introduce new reagents and does not have new risks, and can simultaneously meet the goals of rationally utilizing resources, protecting the environment and reducing costs.

[0045] The second aspect of the present application provides a recovery device for aluminum electrochemical polishing waste liquid used in the above-mentioned recovery method, see Figure 3 In one embodiment, the recovery device 100 for aluminum electrochemical polishing waste liquid includes an overflow auxiliary tank 11, a waste liquid tank 12, a dilution tank 13, a diffusion dialysis device 14 and an evaporation device 15, wherein the overflow auxiliary tank 11 is used to connect with the aluminum electrochemical polishing tank 200, and transport the aluminum electrochemical polishing waste liquid to the waste liquid tank 12 in an overflow manner, the waste liquid tank 12 is connected to the dilution tank 13, the dilution tank 13 is connected to the diffusion dialysis device 14, and the diffusion dialysis device 14 is connected to the evaporation device 15.

[0046] In the above embodiment, the liquid in the aluminum electrochemical polishing tank 200 first flows into the overflow auxiliary tank 11, and after circulating filtration in the overflow auxiliary tank 11, a portion of the liquid is added to the aluminum electrochemical polishing tank 200, which can save costs while maintaining the ideal concentration of each ion in the aluminum electrochemical polishing tank 200. It can be understood that the liquid in the aluminum electrochemical polishing tank 200 flows into the overflow auxiliary tank 11 in an overflow manner.

[0047] When the overflow auxiliary tank 11 is full, it transports liquid to the waste liquid tank 12 in an overflow manner. The liquid transported at this time is the aluminum electrochemical polishing waste liquid.

[0048] The waste liquid tank 12 is connected to the dilution tank 13, and the aluminum electrochemical polishing waste liquid and dilution water in the waste liquid tank are introduced into the dilution tank 13, and the aluminum electrochemical polishing waste liquid is diluted with the dilution water. It can be understood that before or after the dilution treatment, the step of filtering the aluminum electrochemical polishing waste liquid to remove solid impurities is also included. It can be understood that the filtration is completed before the diffusion dialysis treatment to meet the quality requirements of entering the diffusion dialysis equipment.

[0049] The dilution tank 13 is connected to the diffusion dialysis equipment 14 to perform diffusion dialysis treatment on the diluted feed liquid to be treated.

[0050] The diffusion dialysis device 14 is connected to the evaporation device 15 to perform evaporation treatment on the recovery liquid after the diffusion dialysis treatment.

[0051] The above-mentioned recovery device is suitable for the above-mentioned recovery method. It can solve the problem of low initial investment and operation cost of the enterprise, and has environmental protection and high recovery rate.

[0052] The following is further described in conjunction with specific embodiments and comparative examples. The raw materials involved in the following specific embodiments and comparative examples, unless otherwise specified, can all be commercially available, the instruments used, unless otherwise specified, can all be commercially available, and the processes involved, unless otherwise specified, are all routinely selected by those skilled in the art.

[0053] In the following specific embodiments and comparative examples, an automatic analyzer is used to detect the content of sulfuric acid, phosphoric acid and metal ions in the treated feed liquid, recovered acid, residual liquid and evaporated concentrated liquid, wherein the automatic analyzer uses potentiometric titration to analyze the content of sulfuric acid, phosphoric acid and metal ions, and when titrated with a standard sodium hydroxide alkaline solution, the pH value of the mixed acid undergoes a sudden jump. The ion concentration is measured by measuring the change in electrode potential. The concentration of the measured ion changes continuously, and thus the potential of the indicator electrode changes accordingly. Near the titration end point, the concentration of the measured ion changes suddenly, thereby causing a sudden change in the electrode potential, and the titration end point can be determined based on the sudden jump in the electrode potential. During the determination, the temperature of the liquid to be tested is adjusted to room temperature, 50 μL of the liquid to be tested is taken and diluted to 80 mL~100 mL with pure water, and after being mixed evenly, the content of sulfuric acid, phosphoric acid and metal ions is detected using an automatic analyzer.

[0054] In the following specific examples and comparative examples, the recovery rates of sulfuric acid and phosphoric acid were calculated by the following calculation method:

[0055] The acid recovery rate is calculated as follows: acid concentration in the recovery liquid × acid volume in the recovery liquid ÷ acid concentration in the aluminum electrochemical polishing waste liquid ÷ volume of aluminum electrochemical polishing waste liquid × 100%.

[0056] Al 3+ The interception rate is calculated as follows: 100% - aluminum concentration in the recovery liquid × the volume of the recovery liquid ÷ aluminum concentration in the aluminum electrochemical polishing waste liquid ÷ the volume of the aluminum electrochemical polishing waste liquid × 100%.

[0057] Example 1

[0058] This embodiment provides a method and device for recovering aluminum electrochemical polishing waste liquid, and the steps are as follows:

[0059] Step 1: The aluminum electrochemical polishing waste liquid recovery device of this embodiment is shown in Figure 3 First, the aluminum electrochemical polishing waste liquid is passed through a bag filter and a security filter to remove large-sized solid suspended matter, and then passed through a microfiltration system with a pore size of 1 μm to remove small-sized solid impurities. Dilution water is added to the filtered aluminum electrochemical polishing waste liquid at a volume ratio of 2:1 to dilute it to obtain a liquid to be treated, wherein the Al in the liquid to be treated is 3+ The concentration is 23.57g / L.

[0060] Step 2: Pass the treated liquid and water into the diffusion dialysis equipment, so that the treated liquid and water flow through the anion exchange membrane in reverse direction, and control the flow rate of the treated liquid to 80 L / h and the flow rate of water to 240 L / h (at this time, the flow rate ratio of the treated liquid to water is 1:3). Collect the liquid flowing out of the water side, which is the recovered liquid, and collect the liquid flowing out of the treated liquid side, which is the residual liquid.

[0061] The sulfuric acid content in the recovered liquid was 170g / L, the phosphoric acid content was 99.2g / L, and no Al was detected. 3+ (i.e. Al 3+ The interception rate is 100%). The sulfuric acid content in the test residue is 23.4g / L, the phosphoric acid content is 113.94g / L, and the Al 3+ The content is 16g / L.

[0062] Calculation shows that the sulfuric acid recovery rate in this embodiment is 93.16%, and the phosphoric acid recovery rate is 62.01%.

[0063] Step 3: Evaporating and concentrating the recovered liquid.

[0064] Example 2

[0065] This embodiment provides a method and device for recovering aluminum electrochemical polishing waste liquid, which is basically the same as that of embodiment 1, except that: in step 1, dilution water is added to the filtered aluminum electrochemical polishing waste liquid at a volume ratio of 1.8:1 to perform dilution treatment to obtain a to-be-treated feed liquid, wherein the Al in the to-be-treated feed liquid is 3+ The concentration is 21.51g / L.

[0066] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ The calculation shows that the sulfuric acid recovery rate of this embodiment is 96.04%, the phosphoric acid recovery rate is 57.44%, and the Al 3+ The interception rate is 100%.

[0067] Example 3

[0068] This embodiment provides a method and device for recovering aluminum electrochemical polishing waste liquid, which is basically the same as that of embodiment 1, except that, in step 1, dilution water is added to the filtered aluminum electrochemical polishing waste liquid at a volume ratio of 2.5:1 to perform dilution treatment to obtain a to-be-treated feed liquid, wherein the Al in the to-be-treated feed liquid is 3+ The concentration is 25.63g / L.

[0069] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ The calculation shows that the sulfuric acid recovery rate of this embodiment is 96.88%, the phosphoric acid recovery rate is 62.83%, and the Al 3+ The interception rate is 100%.

[0070] Example 4

[0071] This embodiment provides a method and device for recovering aluminum electrochemical polishing waste liquid, which is basically the same as that of embodiment 1, except that, in step 1, dilution water is added to the filtered aluminum electrochemical polishing waste liquid at a volume ratio of 3:1 to perform dilution treatment to obtain a to-be-treated feed liquid, wherein the Al in the to-be-treated feed liquid is 3+ The concentration is 26.21g / L.

[0072] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ The calculation shows that the sulfuric acid recovery rate of this embodiment is 94.68%, the phosphoric acid recovery rate is 70.53%, and the Al 3+ The interception rate is 100%.

[0073] Example 5

[0074] The present embodiment provides a method and device for recovering waste liquid from electrochemical polishing of aluminum materials, which is basically the same as Example 1, with the main difference that, in step 2, the flow rate of the liquid to be treated is controlled to be 100 L / h, and the flow rate of water is controlled to be 260 L / h (at this time, the flow ratio of the liquid to be treated and water is 1:2.6).

[0075] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ The calculation shows that the sulfuric acid recovery rate of this embodiment is 97.58%, the phosphoric acid recovery rate is 67.09%, and the Al 3+ The interception rate is 100%.

[0076] Example 6

[0077] The present embodiment provides a method and device for recovering waste liquid from electrochemical polishing of aluminum materials, which are basically the same as those in Embodiment 1, with the main difference being that in step 2, the flow rate of the liquid to be treated is controlled to be 86 L / h, and the flow rate of water is controlled to be 220 L / h (at this time, the flow rate ratio of the liquid to be treated and water is 1:2.56).

[0078] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ The calculation shows that the sulfuric acid recovery rate in this embodiment is 97.01%, the phosphoric acid recovery rate is 65.19%, and the Al 3+ The interception rate is 100%.

[0079] Comparative Example 1

[0080] This comparative example provides a method and device for recovering waste liquid from electrochemical polishing of aluminum materials, which are basically the same as Example 1, with the main difference that, in step 2, the flow rate of the liquid to be treated is controlled to be 260 L / h, and the flow rate of water is controlled to be 220 L / h (at this time, the flow ratio of the liquid to be treated and water is 1:0.85).

[0081] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ The calculation shows that the sulfuric acid recovery rate of this embodiment is 81.97%, the phosphoric acid recovery rate is 41.35%, and the Al 3+ The interception rate is 100%.

[0082] Comparative Example 2

[0083] This comparative example provides a method and device for recovering waste liquid from electrochemical polishing of aluminum materials, which are basically the same as Example 1, with the main difference that, in step 2, the flow rate of the liquid to be treated is controlled to be 90 L / h, and the flow rate of water is controlled to be 540 L / h (at this time, the flow ratio of the liquid to be treated and water is 1:6).

[0084] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ The calculation shows that the sulfuric acid recovery rate in this embodiment is 83.56%, the phosphoric acid recovery rate is 41.27%, and the Al 3+ The interception rate is 100%.

[0085] Comparative Example 3

[0086] This comparative example provides a method and device for recovering aluminum electrochemical polishing waste liquid, which are basically the same as those in Example 1, except that, in step 1, dilution water is added to the filtered aluminum electrochemical polishing waste liquid at a volume ratio of 5:1 to perform dilution treatment to obtain a to-be-treated feed liquid, wherein the Al in the to-be-treated feed liquid is 3+ The concentration is 34g / L.

[0087] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ Calculations show that the sulfuric acid recovery rate of this embodiment is 95.31%, the phosphoric acid recovery rate is 50.47%, and the metal ion retention rate is 100%.

[0088] Comparative Example 4

[0089] This comparative example provides a method and device for recovering aluminum electrochemical polishing waste liquid, which are basically the same as those in Example 1, except that, in step 1, dilution water is added to the filtered aluminum electrochemical polishing waste liquid at a volume ratio of 6:1 to perform dilution treatment to obtain a to-be-treated feed liquid, wherein the Al in the to-be-treated feed liquid is 3+ The concentration is 36g / L.

[0090] Test the sulfuric acid content, phosphoric acid content and Al in the recovered liquid 3+ It can be calculated that the sulfuric acid recovery rate of this embodiment is 81.97%, the phosphoric acid recovery rate is 41.35%, and the metal ion retention rate is 100%.

[0091] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for recovering aluminum electrochemical polishing waste liquid, characterized in that: The following steps are involved: The aluminum electrochemical polishing waste liquid is diluted to obtain Al 3+ The concentration of the treated liquid is not higher than 30g / L; The treated liquid and water are respectively introduced into both sides of the anion exchange membrane in reverse direction, and the flow ratio of the treated liquid and water is controlled to be 1: (1-5), and the liquid flowing out of the water side is collected to obtain the recovered acid.

2. The method for recovering aluminum electrochemical polishing waste liquid according to claim 1, characterized in that: The aluminum electrochemical polishing waste liquid comprises the following components: H2SO4, H3PO4 and Al 3+ .

3. The method for recycling aluminum electrochemical polishing waste liquid according to claim 1, characterized in that: The volume ratio of the aluminum electrochemical polishing waste liquid to the dilution water is (1-4):

1.

4. The method for recovering aluminum electrochemical polishing waste liquid according to claim 1, characterized in that: The flow rate of the liquid to be treated is 45L / h~200L / h.

5. The method for recycling aluminum electrochemical polishing waste liquid according to claim 1, characterized in that: The water flow rate is 160L / h~320L / h.

6. The method for recycling aluminum electrochemical polishing waste liquid according to claim 1, characterized in that: The material of the anion exchange membrane includes a polyether polymer compound containing phenyl.

7. The method for recovering aluminum electrochemical polishing waste liquid according to any one of claims 1 to 6, characterized in that: The method also includes a step of evaporating and concentrating the recovered acid.

8. The method for recovering aluminum electrochemical polishing waste liquid according to claim 7, characterized in that: After the recovered acid is evaporated and concentrated, the method further comprises the following steps: adding or not adding acid solution to the recovered acid after evaporation and concentration, and recycling the acid to the electrolyte for electrochemical polishing of aluminum materials.

9. The method for recovering aluminum electrochemical polishing waste liquid according to any one of claims 1 to 6 and 8, characterized in that: Before the liquid to be treated is introduced into one side of the anion exchange membrane, the method further comprises the following steps: filtering to remove solid impurities.

10. A device for recovering waste liquid from electrochemical polishing of aluminum materials, used in the recovery method according to any one of claims 1 to 9, characterized in that: It comprises a waste liquid tank, a dilution tank and a diffusion dialysis device. The waste liquid tank is connected to the dilution tank, and the dilution tank is connected to the diffusion dialysis device.

11. The device for recovering waste liquid from electrochemical polishing of aluminum materials according to claim 10, characterized in that: It also includes an evaporation device, which is connected to the diffusion dialysis device.

12. The device for recovering aluminum electrochemical polishing waste liquid according to any one of claims 10 to 11, characterized in that: It also includes an overflow auxiliary tank, which is used to connect with the aluminum electrochemical polishing tank and transport the aluminum electrochemical polishing waste liquid to the waste liquid tank in an overflow manner.

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