WO2021169482A1

WO2021169482A1 - Device and method for multistage selective removal of heavy metal ions in photovoltaic waste liquid

Info

Publication number: WO2021169482A1
Application number: PCT/CN2020/135178
Authority: WO
Inventors: 蒋新; 赵会; 施利君; 屠金玲
Original assignee: 苏州晶洲装备科技有限公司
Priority date: 2020-02-26
Filing date: 2020-12-10
Publication date: 2021-09-02
Also published as: WO2021169483A1; CN111233202A

Abstract

A device and method for multistage selective removal of heavy metal ions in a photovoltaic waste liquid. According to the device, a multistage metal adsorption mechanism is used for selectively adsorbing and removing heavy metal ions in a dialysate and cleaning liquid; according to the method, different metal ions are directionally adsorbed and removed by means of different types of resin adsorption columns arranged in each stage of the metal adsorption mechanism; after the adsorption reaches saturation, the surface of resin for adsorption is eluted by means of eluent, and metal ions are recycled.

Description

Device and method for multi-stage selective removal of heavy metal ions in photovoltaic waste liquid

Technical field

The application relates to the technical field of environmental protection treatment, in particular to the technical field of waste liquid recovery treatment, and in particular to a device for multi-stage selective removal of heavy metal ions in silicon texturing wastewater.

Background technique

Wet black silicon technology uses gold, silver and other precious metal particles randomly attached to the surface of the silicon wafer as the cathode, and silicon as the anode. At the same time, a micro-electrochemical reaction channel is formed on the silicon surface, and the silicon substrate is quickly etched under the metal particles to form a nanostructure. Chemical solvents such as KOH, HNO3, H2O2, ammonia, hydrofluoric acid, etc. are also used in polishing, digging, desilvering and reaming in the production process. Therefore, wet black silicon technology will generate a large amount of silver ions and other heavy metal ions. Such as waste acid solution of zinc, iron, manganese, copper, nickel, chromium, cadmium, etc. Among them, the content of silver ions is the largest, about 98800ppb, the content of nitric acid is about 30% to 35%, hydrofluoric acid is 3% to 4%, and fluorosilicic acid is 4% to 5%. If it is directly disposed of as hazardous waste, this It will undoubtedly cause a great waste of resources. Therefore, in consideration of maximizing resource utilization, it is necessary to recycle the nitric acid, hydrofluoric acid, and metal ion silver.

The best technology for recovering nitric acid and hydrofluoric acid in waste mixed acid is diffusion dialysis. Its advantage is that the recovery rate of nitric acid and hydrofluoric acid is high, which can reach 80% to 90%, and the recovery device occupies a small area and is easy to operate. , And almost no energy consumption, but the disadvantage is that it will produce about the same volume of dialysate, and the dialysate contains about 90% of the original solution of metal ions and about 10% to 20% acid. Due to the large metal ion content and low pH of this dialysate, it cannot be directly discharged. It must be treated before it can be discharged to the factory. Otherwise, it will cause environmental pollution and the loss of precious metals contained in the dialysate will also cause Economic losses.

Therefore, how to treat these waste acid solutions containing precious metal silver ions and other heavy metal ions is a technical problem that needs to be solved urgently at present.

Summary of the invention

The purpose of this application is to provide a multi-stage selective removal of heavy metal ions in photovoltaic waste liquid. Its overall structure is simple, and it can collect different metal ions step by step, improve resource recovery and utilization, and improve environmental protection at the same time. Can reduce production and processing costs.

Furthermore, the present application also provides a multi-stage method for selectively removing heavy metal ions in photovoltaic waste liquid. Combining with the characteristics of the dialysate, it can adjust and increase the pH value step by step, and realize the improvement of gold, silver, iron, zinc, copper, manganese, and lead. The adsorption and separation of the three different metal ions of chromium, nickel and cadmium improves the resource recovery rate.

In order to achieve the above-mentioned purpose, the technical solution adopted in this application is:

This application provides a multi-stage selective removal of heavy metal ions in photovoltaic waste liquid, which is used to treat the dialysis liquid after the diffusion dialysis treatment of the waste liquid produced by wet-process black silicon, including a multi-stage series-connected first The metal adsorption mechanism, the second metal adsorption mechanism, and the third metal adsorption mechanism perform adsorption and removal of different metal ions through the first metal adsorption mechanism, the second metal adsorption mechanism, and the third metal adsorption mechanism. The adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are respectively provided with resin adsorption columns for selectively adsorbing corresponding metal ions.

For the above technical solutions, the applicant has further optimization measures.

Further, the structure of the first metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are basically the same, wherein each metal adsorption mechanism includes a buffer tank, a transfer pump and a resin adsorption column, and the buffer tank is used for storage The pH value of the wastewater is adjusted, the inlet end of the delivery pump is connected to the buffer tank, and the outlet end is connected to the lower part of the resin adsorption column, and the upper part of the resin adsorption column is passed into the next-stage mechanism.

Further, the resin adsorption column in the first metal adsorption mechanism adopts a mercapto-type chelating resin adsorption column or a carboxymethyl chitosan thiourea resin adsorption column, and the resin adsorption column in the second metal adsorption mechanism adopts It is an imino oxalic acid chelating resin adsorption column, and the resin adsorption column in the third metal adsorption mechanism uses an amine chelating resin.

Further, the device is respectively provided with a first elution mechanism, a second elution mechanism and a third elution mechanism corresponding to each metal adsorption mechanism, and the first elution mechanism, the second elution mechanism and the third elution mechanism The structure of the mechanism is basically the same. Each elution mechanism includes a high-pressure purge gas path, an eluent storage tank, and a recovery tank. The inlet of the high-pressure purge gas path is located at the top of the resin adsorption column. The outlet of the storage tank is connected with the eluent inlet on the resin adsorption column, the bottom end of the resin adsorption column is provided with an eluent outlet, and the eluent outlet is connected with the recovery tank through a pipeline.

Furthermore, the buffer tanks in the first metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are all jacketed and electrically stirred reactors.

Further, a coagulation sedimentation tank is provided at the rear end of the third metal adsorption mechanism, the wastewater treated by the third metal adsorption mechanism is discharged into the coagulation sedimentation tank, and the coagulation sedimentation tank is After adding coagulation and precipitation agent, it is used to remove aluminum ions in wastewater.

In particular, this application also provides a multi-stage method for selectively removing heavy metal ions in photovoltaic waste liquid, which is used to treat the dialysis liquid after the diffusion dialysis treatment of the waste liquid produced by wet-process black silicon. The processing steps include :

The dialysate is transported to the first buffer tank for pH adjustment, the pH value is controlled to 2 to 4, and then the dialysate in the first buffer tank is fed from below the first resin adsorption column through the first transfer pump for adsorption treatment The latter dialysate is sent from above the first resin adsorption column and flows into the second buffer tank of the next stage;

The liquid flowing out from the first resin adsorption column is sent to the second buffer tank for pH adjustment, the pH value is controlled to 5-6, and then the dialysis liquid in the second buffer tank is transferred from the second resin through the second transfer pump The dialysis solution after the adsorption treatment is sent from the top of the second resin adsorption column to flow into the third buffer tank of the next stage;

The liquid flowing out from the second resin adsorption column is sent to the third buffer tank for pH adjustment, and the pH value is controlled to 6-7, and then the dialysate in the third buffer tank is transferred from the third resin through the third transfer pump. The dialysis solution after the adsorption treatment is sent out from the top of the third resin adsorption column.

Further, the liquid flowing out from above the third resin adsorption column enters the coagulation sedimentation tank, the pH value of the liquid in the coagulation sedimentation tank is adjusted to 7-8, and then the coagulation sedimentation agent is added and then stirred , Settling, filtering, and processing after the supernatant in the coagulation sedimentation tank reaches the standard.

Further, the first buffer tank, the second buffer tank, and the third buffer tank are all jacketed and heatable stirrable reactors, and the liquid temperature of the reactor is controlled at 15-20°C.

Further, when any one of the first resin adsorption column, the second resin adsorption column, and the third resin adsorption column reaches adsorption saturation, dilute nitric acid or dilute hydrochloric acid is used as the eluent for the saturated resin adsorption column , The metal ions adsorbed on the resin surface are eluted and recovered.

Due to the application of the above technical solutions, this application has the following advantages compared with the prior art:

The multi-stage selective removal of heavy metal ions in photovoltaic waste liquid of this application uses a multi-stage metal adsorption mechanism to selectively adsorb and remove heavy metal ions in the dialysate and cleaning liquid, and pass through each level of metal respectively. Different types of resin adsorption columns set in the adsorption mechanism perform directional adsorption and removal of different metal ions. After the adsorption is saturated, the surface of the resin used for adsorption is eluted by the eluent, and the metal ions are recovered to achieve metal Reuse, especially for the recovery of precious metals such as gold and silver.

Furthermore, due to the unsatisfactory effect of resin adsorption on the removal of aluminum ions, a coagulation precipitation tank is used in the device to add a coagulation precipitation agent to the dialysate to remove aluminum ions, so as to maximize the removal of metal ions in the dialysate. It can meet the emission standards, or it can be discharged to the field for recycling.

In addition, the multi-stage selective removal of heavy metal ions in photovoltaic waste liquid of the present application utilizes the different forces between different metals and resin functional groups, so that different resin adsorption columns can selectively adsorb heavy metal ions, thereby achieving separation Heavy metals play a vital role in the subsequent recovery of metals, especially precious metals such as gold and silver. At the same time, due to the selective adsorption of heavy metals, the removal rate of heavy metals is as high as 90%. At the same time, the pH value of the wastewater is adjusted step by step, so that the treated wastewater can meet the discharge standard, which greatly reduces the wastewater treatment cost of the enterprise. Therefore, the promotion of this method can ensure high economic and environmental benefits.

Description of the drawings

Hereinafter, some specific embodiments of the present application will be described in detail in an exemplary but not restrictive manner with reference to the accompanying drawings. The same reference numerals in the drawings indicate the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the attached picture:

Fig. 1 is a schematic diagram of the overall structure of a multi-stage selective removal of heavy metal ions in photovoltaic waste liquid according to an embodiment of the present application.

Among them, the reference signs are described as follows:

1. The first buffer tank, 2. The first transfer pump, 3. The first resin adsorption column, 4. The second buffer tank, 5. The first transfer pump, 6. The second resin adsorption column, 7. The third buffer tank , 8, the third transfer pump, 9, the third resin adsorption column, 10, coagulation sedimentation tank, 11, storage tank, 12, output water pump, 13, the first recovery tank, 14, the second recovery tank, 15, The third recovery tank, 16, the first eluent storage tank, 17, the first eluent pump, 18, the second eluent storage tank, 19, the second eluent pump.

Detailed ways

The technical solutions of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments.

In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the pointed device or element must have a specific orientation or a specific orientation. The structure and operation cannot therefore be understood as a limitation of this application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance, such as the first heating tube, the second heating tube, and the third heating tube, It is to be able to describe the product structure more clearly, not to limit its importance.

In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

Adsorption resin refers to a type of high molecular polymer, which can be used to remove organic matter in wastewater, decolorize sugar liquid, separate and refine natural products and biochemical products, etc. There are many kinds of adsorption resins, and the changes of monomers and functional groups on the monomers can give the resin various special properties. Commonly used are high molecular polymers such as polystyrene resin and polyacrylate resin. Adsorbent resin is a resin adsorbent with a porous three-dimensional structure characterized by adsorption. It is a porous resin newly developed in the polymer field in recent years. It is made of styrene and divinylbenzene and other monomers, in the presence of toluene and other organic solvents, by suspension copolymerization of fish roe-like small rounds. ball. The resin adsorption column in this application is constructed by carrying a specific adsorption resin in a columnar container.

Example 1:

This embodiment describes a multi-stage selective removal of heavy metal ions in photovoltaic waste liquid, which is used to treat the dialysis liquid after the diffusion dialysis treatment of the waste liquid produced by wet-process black silicon, including multi-stage series connection A metal adsorption mechanism, a second metal adsorption mechanism, and a third metal adsorption mechanism are used to adsorb and remove different metal ions through the first metal adsorption mechanism, the second metal adsorption mechanism, and the third metal adsorption mechanism, respectively. The metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are respectively provided with resin adsorption columns for selectively adsorbing corresponding metal ions.

As shown in Figure 1, the first metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are basically the same in structure, wherein the first metal adsorption mechanism includes a first buffer tank 1, a first delivery pump 2, and The first resin adsorption column 3, the first buffer tank 1 is used to store waste water and adjust the pH value therein, the liquid inlet end of the first delivery pump 2 is connected to the first buffer tank 1, the first delivery pump 2 The outlet end of the first resin adsorption column 3 is connected to the lower part of the first resin adsorption column 3, and the upper part of the first resin adsorption column 3 passes into the next level mechanism, that is, the second buffer tank 4 of the second metal adsorption mechanism. .

In other words, the second metal adsorption mechanism includes a second buffer tank 4, a second transfer pump 5, and a second resin adsorption column 6. The second buffer tank 4 receives the wastewater from the first resin adsorption column 3 and adjusts the pH value, the inlet end of the second delivery pump 5 is connected to the second buffer tank 4, and the outlet end of the second delivery pump 5 is connected to the lower part of the second resin adsorption column 6. The upper part of the second resin adsorption column 6 passes into the next level mechanism, that is, the third buffer tank 7 of the third metal adsorption mechanism. The third metal adsorption mechanism includes a third buffer tank 7, a third transfer pump 8 and a third resin adsorption column 9. The third buffer tank 7 receives wastewater from the second resin adsorption column 6 and adjusts the pH value therein. The inlet end of the third delivery pump 8 is connected to the third buffer tank 7, and the outlet end of the third delivery pump 8 is connected to the lower part of the third resin adsorption column 9, and the third resin adsorption column The upper part of 9 leads to the next level of organization area for processing, such as discharge or other processing.

In order to ensure the temperature of the dialysate during processing and complete the reaction, the buffer tanks in the first metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are all jacketed and electrically stirred reactors. The liquid can be heated and stirred.

Specifically, the resin adsorption column in the first metal adsorption mechanism adopts a mercapto-type chelating resin adsorption column or a carboxymethyl chitosan thiourea resin adsorption column, and the selected mercapto-type chelating resin adsorption column or a carboxymethyl chelating resin adsorption column is used. Methyl chitosan thiourea resin, because of its high selective adsorption performance for gold ions and silver ions, and high elution rate (>90%), good reusability, currently observed in repeated use 5 times Afterwards, its adsorption capacity is not significantly reduced, and the above two types of resins can effectively separate and recover precious metals from mixed metal wastewater to achieve relatively high purity and recovery rate.

The resin adsorption column in the second metal adsorption mechanism adopts imino oxalic acid chelating resin adsorption column. The selected imino oxalic acid chelating resin is mostly Amberlite IRC-718 type, Lewatit TP-207 type, the above two types of chelating resins show a high adsorption effect on iron ions, zinc ions, and manganese ions.

The resin adsorption column in the third metal adsorption mechanism uses amine chelating resins, such as Dowex M-4195, Purolite S-985, Diaion CR-20 and other types of amine chelating resins can be used. Copper ion, nickel ion, chromium ion, cadmium ion, lead ion and other ions are selectively adsorbed.

Because the above resin adsorption column has an unsatisfactory effect on aluminum ion adsorption, the waste liquid can be transported to the coagulation sedimentation tank 10 after most of the metal ions are processed through the above steps, and the mixing is provided at the rear end of the third metal adsorption mechanism. In the coagulation sedimentation tank 10, the upper end of the third resin adsorption column 9 is connected to the coagulation sedimentation tank 10, and the wastewater treated by the third metal adsorption mechanism is discharged into the coagulation sedimentation tank 10. The coagulation sedimentation tank 10 is used to remove aluminum ions in wastewater after adding a coagulation sedimentation agent. Adding coagulation precipitation agent to directional removal of aluminum ions. Stir for 15 to 30 minutes, and settle for 30 to 60 minutes. Take the supernatant and analyze and determine the content of each component. After reaching the standard, the supernatant is discharged or processed in the factory, and the lower sediment is taken out, evaporated and dried, and processed in a centralized manner.

In order to be able to effectively elute the metal ions in the metal adsorption mechanism, the device corresponds to the first metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism, respectively, provided with a first elution mechanism, a second elution mechanism and The third elution mechanism, the structure of the first elution mechanism, the second elution mechanism and the third elution mechanism are basically the same, wherein each elution mechanism includes a high-pressure purge gas path and an

eluent storage tank

16 , 18 and

recovery tanks

13, 14, the inlet of the high-pressure purge gas path is located at the top of the resin adsorption column, and the outlets of the

eluent storage tanks

16, 18 are respectively connected to the eluent inlet on the corresponding resin adsorption column An eluent outlet is provided at the bottom end of the resin adsorption column, and the eluent outlet is connected to the corresponding

recovery tanks

13, 14 through pipelines.

Example 2:

This application also provides a method for multi-stage selective removal of heavy metal ions in photovoltaic waste liquid. The method is based on the device described in Example 1, and is used to treat the waste liquid produced by wet-process black silicon after diffusion dialysis. The dialysate is processed, and the processing steps include:

The dialysate is transported to the first buffer tank 1 for pH adjustment. The first buffer tank 1 is a jacketed and heatable stirrable reactor. The temperature of the solution in the reactor is adjusted to 15-20°C. Take a sample from the sampling port under the first buffer tank 1, measure the H+ concentration, calculate the amount of lye such as NaOH or KOH that needs to be added, and adjust the pH to about 2 to 4. If the pH is greater than this range, you can add dilute nitric acid for adjustment. The adsorption rate of the first resin adsorption column 3 is relatively high under the pH value. Then, the dialysate in the first buffer tank 1 is sent from below the first resin adsorption column 3 through the first delivery pump 2, and the dialysate after adsorption treatment is sent out from the top of the first resin adsorption column 3 and flows into it. To the second buffer tank 4 of the next stage. The first resin adsorption column 3 is a resin type that selectively adsorbs gold and silver ions, such as a mercapto-type chelating resin adsorption column, carboxymethyl chitosan thiourea resin;

The liquid flowing out from the first resin adsorption column 3 is sent to the second buffer tank 4 for pH adjustment. The second buffer tank 4 is a jacketed, heatable and stirrable reactor. The temperature of the solution is 15-20℃, take a sample at the sampling port under the second buffer tank 4, measure the H+ concentration, calculate the amount of lye such as NaOH or KOH that needs to be added, and adjust the pH to about 2 to 4, if the pH is greater than this range , Can be adjusted by adding dilute nitric acid, at this pH value, the adsorption rate of the first resin adsorption column 3 is higher. Then the dialysate in the second buffer tank 4 is sent from below the second resin adsorption column 6 via the second transfer pump 5, and the dialysate after the adsorption treatment is sent out from the top of the second resin adsorption column 6 and flows into it. To the third buffer tank 7 of the next stage. The second resin adsorption column 6 is a resin type that selectively adsorbs metal ions such as iron, zinc, copper, manganese, etc., and imino oxalic acid chelating resins can be used, such as Amberlite IRC-718 type, Lewatit TP- Type 207;

The liquid flowing out from the second resin adsorption column 6 is sent to the third buffer tank 7 for pH adjustment. The temperature of the solution is 15-20℃, take a sample at the sampling port below the third buffer tank 7, measure the H+ concentration, calculate the amount of lye such as NaOH or KOH that needs to be added, and adjust the pH to about 2 to 4, if the pH is greater than this range , Can be adjusted by adding dilute nitric acid, at this pH value, the adsorption rate of the first resin adsorption column 3 is higher. Then, the dialysate in the third buffer tank 7 is sent from below the third resin adsorption column 9 via the third delivery pump 8, and the dialysate after the adsorption treatment is sent out from the top of the third resin adsorption column 9. The third resin adsorption column 9 is a resin type that selectively adsorbs copper ions, nickel ions, chromium ions, cadmium ions, and lead ions. Amine chelating resins can be used, such as Dowex M-4195, Purolite S-985, Diaion CR -20 and other types of amine chelating resins.

The liquid flowing out from the top of the third resin adsorption column 9 enters the coagulation sedimentation tank 10, adjust the temperature of the solution in the coagulation sedimentation tank 10 to 15-20 ℃, and take a sample at the upper sampling port to measure the content of each component Content, adjust the pH to 7-8, add a coagulation precipitation agent, such as polyaluminum chloride, polyaluminum sulfate, polyaluminum phosphate, polyferric sulfate, polyferric chloride, Polymeric ferric phosphate, polyferrous iron and anionic, such as polymeric silicic acid, etc., are stirred, filtered, precipitated, the supernatant is taken to measure the content of each component, and after reaching the standard, it is discharged through the output water pump 12 or sent to the factory.

In addition, samples are taken regularly at the outlets above the first, second, and third resin adsorption columns 9 to measure the content of each component. If the content of each component in the effluent is found to increase, it indicates that the adsorption has reached saturation and needs to be eluted. When any one of the first resin adsorption column 3, the second resin adsorption column 6 and the third resin adsorption column 9 reaches adsorption saturation, dilute nitric acid or dilute hydrochloric acid is used as the eluent for the saturated resin adsorption column , The metal ions adsorbed on the resin surface are eluted and recovered.

Take the first resin adsorption column 3 that needs to be eluted as an example. When eluting, first use compressed air to blow in from above the first resin adsorption column 3, blow out the remaining liquid from below, and transport it to the first buffer tank 1 connected to the first resin adsorption column 3, and then use dilute nitric acid for elution. . Here, the eluent of the first resin adsorption column 3 uses dilute nitric acid instead of hydrochloric acid, because if dilute hydrochloric acid is used, it will react with silver ions to form a silver chloride precipitate, which is easy to adhere to the resin particles, which is good for the second resin adsorption When the column 6 or the third resin adsorption column 9 is used for elution, not only dilute nitric acid but also dilute hydrochloric acid can be used for elution. In order to save costs, the second resin adsorption column 6 or the third resin adsorption column 9 can use the same An eluent storage tank. Therefore, in this embodiment, the eluate of the first resin adsorption column 3 is supplied from the first eluate storage tank 16 through the first elution pump 17, while the second resin adsorption column 6 and the third resin adsorption column The eluent of 9 is supplied from the second eluent storage tank 18 through the second eluent pump 19.

When the first resin adsorption column 3 is eluted, the eluent enters from the top of the first resin adsorption column 3 and flows out of the first resin adsorption column 3 from below. In this process, the flow rate is adjusted within a proper range, and the eluent flows out. Collected in the first recovery tank 13, relatively, the eluate that flows out when the second resin adsorption column 6 is eluted will enter the second recovery tank 14, and the third resin adsorption column 9 will be eluted. The eluent flowing out at this time will enter the third recovery tank 15. Among them, the first recovery tank 13 contains relatively high concentrations of silver ions and gold ions, which can be oriented for subsequent processing to recover gold and silver elements, and so on, and the second recovery tank 14 also contains relatively high concentrations of iron, zinc, copper, and manganese. Such as metal ions, the second recovery tank 14 also contains relatively high concentrations of copper ions, nickel ions, chromium ions, cadmium ions, and lead ions.

After the elution is completed, use compressed air to purge for another 3 to 5 minutes to purge the residual eluent in the resin adsorption column to the corresponding recovery tank, and then proceed to the next cycle of the resin adsorption process.

In other words, the adsorption-purge-elution-purge-adsorption process is carried out cyclically as described above to achieve the recovery of different types of metal ions, especially gold and silver ions, and the removal of other ions. The treated water metal The ion meets the national first-level sewage discharge standard and is easy to operate.

The above-mentioned embodiments are only to illustrate the technical ideas and features of the application, and their purpose is to enable those familiar with the technology to understand the content of the application and implement them accordingly, and cannot limit the scope of protection of the application.

Claims

A multi-stage device for selectively removing heavy metal ions in photovoltaic waste liquid, which is used to treat the dialysis liquid of the waste liquid produced by wet-process black silicon after diffusion dialysis treatment, wherein the device includes a multi-stage series-connected first metal The adsorption mechanism, the second metal adsorption mechanism, and the third metal adsorption mechanism perform adsorption and removal of different metal ions through the first metal adsorption mechanism, the second metal adsorption mechanism, and the third metal adsorption mechanism. The first metal adsorption The mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are respectively provided with resin adsorption columns for selectively adsorbing corresponding metal ions.
The device according to claim 1, wherein the structure of the first metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are basically the same, wherein each metal adsorption mechanism includes a buffer tank, a transfer pump, and a resin. Adsorption column, the buffer tank is used to store wastewater and adjust the pH value therein, the inlet end of the delivery pump is connected to the buffer tank, and the outlet end is connected to the lower part of the resin adsorption column, the upper part of the resin adsorption column Access to the next level of institutions.
The device according to claim 2, wherein the resin adsorption column in the first metal adsorption mechanism adopts a mercapto-type chelating resin adsorption column or a carboxymethyl chitosan thiourea resin adsorption column, and the second metal adsorption The resin adsorption column in the mechanism uses imino oxalic acid chelating resin adsorption column, and the resin adsorption column in the third metal adsorption mechanism uses amine chelating resin.
The device according to claim 2 or 3, wherein the device is provided with a first elution mechanism, a second elution mechanism, and a third elution mechanism corresponding to each metal adsorption mechanism, and the first elution mechanism, The structure of the second elution mechanism and the third elution mechanism are basically the same. Each elution mechanism includes a high-pressure purge gas path, an eluent storage tank, and a recovery tank. The inlet of the high-pressure purge gas path is located in the resin At the top of the adsorption column, the outlet of the eluent storage tank is connected with the eluent inlet on the resin adsorption column, the bottom end of the resin adsorption column is provided with an eluent outlet, and the eluent outlet is connected to the The recovery tank is connected by a pipeline.
The device according to claim 2 or 3, wherein the buffer tanks in the first metal adsorption mechanism, the second metal adsorption mechanism and the third metal adsorption mechanism are all jacketed and electrically stirred reactors.
The device according to claim 1, wherein a coagulation sedimentation tank is provided at the rear end of the third metal adsorption mechanism, and the wastewater treated by the third metal adsorption mechanism is discharged into the coagulation sedimentation tank The coagulation sedimentation tank is used to remove aluminum ions in the wastewater after adding a coagulation sedimentation agent.
A multi-stage method for selectively removing heavy metal ions in photovoltaic waste liquid, which is used to treat the dialysis liquid after the diffusion dialysis treatment of the waste liquid produced by wet-process black silicon, wherein the treatment steps include:

The dialysate is transported to the first buffer tank for pH adjustment, the pH value is controlled to 2 to 4, and then the dialysate in the first buffer tank is fed from below the first resin adsorption column through the first transfer pump for adsorption treatment The latter dialysate is sent from above the first resin adsorption column and flows into the second buffer tank of the next stage;

The liquid flowing out from the first resin adsorption column is sent to the second buffer tank for pH adjustment, the pH value is controlled to 5-6, and then the dialysis liquid in the second buffer tank is transferred from the second resin through the second transfer pump The dialysis solution after the adsorption treatment is sent from the top of the second resin adsorption column to flow into the third buffer tank of the next stage;

The liquid flowing out from the second resin adsorption column is sent to the third buffer tank for pH adjustment, and the pH value is controlled to 6-7, and then the dialysate in the third buffer tank is transferred from the third resin through the third transfer pump. The dialysis solution after the adsorption treatment is sent out from the top of the third resin adsorption column.
The method according to claim 7, wherein the liquid flowing out from above the third resin adsorption column enters a coagulation sedimentation tank, the pH value of the liquid in the coagulation sedimentation tank is adjusted to 7-8, and then After adding the coagulation precipitation agent, stirring, precipitation, and filtration are performed, and the supernatant in the coagulation precipitation tank is processed after reaching the standard.
The method according to claim 7, wherein the first buffer tank, the second buffer tank, and the third buffer tank are all jacketed heatable and stirrable reactors, and the liquid temperature of the reactor is Control at 15～20℃.
The method according to any one of claims 7 to 9, wherein when any one of the first resin adsorption column, the second resin adsorption column, and the third resin adsorption column reaches adsorption saturation, the pair reaches saturation The resin adsorption column uses dilute nitric acid or dilute hydrochloric acid as the eluent to elute and recover the metal ions adsorbed on the resin surface.