CN103833167B - Chromic acid wastewater treatment method and treatment system - Google Patents

Abstract

The invention discloses a chromic acid wastewater treatment method, which comprises the steps of carrying out ion exchange on chromic acid wastewater and anion and cation resins, and treating wastewater generated by backwashing and regeneration of the anion and cation resins with saturated exchange capacity in a diaphragm electrolytic cell; also discloses a chromic acid wastewater treatment system, which is used for treating chromic acid wastewater generated by a production system and comprises an anode resin tank; a cathode resin tank; a regeneration and backwashing wastewater collection tank; a reclaimed water storage tank; the diaphragm electrolytic cell is used for carrying out electrolytic treatment on the mixed waste liquid, and comprises a cell body, wherein an ionic diaphragm is also arranged in the cell body and divides the cell body into an inner cell and an outer cell; a cathode plate is arranged in the inner tank, and an anode plate is arranged in the outer tank; a purifying tank; the cathode regenerated liquid storage tank is used for storing a strong alkali solution; an anode regeneration liquid storage tank; the liquid inlet of the production system is respectively connected with the reclaimed water storage tank and the purification tank, and the chromic acid wastewater liquid outlet of the production system is respectively connected with each anode resin tank. The invention is used for occasions of generating chromic acid waste water in the electroplating industry and the like.

Description

Chromic acid wastewater treatment method and treatment system

technical field

The invention relates to a treatment method for chromic acid wastewater, and also relates to a treatment system for chromic acid wastewater.

Background technique

In the prior art, in many industries that generate chromic acid wastewater in the production process, the environmental protection problems caused by the treatment of chromic acid wastewater have always been a big problem to be solved urgently.

For example, in the electroplating industry, the wastewater generated during the electroplating production process mainly comes from the cleaning of plated parts, floor washing, hanger and plate washing, replacement of waste baths, etc. Electroplating wastewater includes pretreatment wastewater, chromium-containing wastewater, chromium-containing alloy waste water, chromic acid waste water, comprehensive waste water, etc., the waste water is generally collected and treated separately.

Among them, chromic acid wastewater mainly contains CrO4 ^2- in the form of acid anions, sulfate radicals, and metal ions in the form of simple cations such as Ni ²⁺ , Cu ²⁺ , Cr ⁶⁺ , Fe ³⁺ , etc., the prior art The treatment methods mainly include chemical reduction neutralization precipitation method and anion and cation resin exchange method. To treat chromic acid wastewater by chemical reduction, neutralization and precipitation, it is necessary to add precipitant, reducing agent, and condensing agent to chromic acid wastewater. Treating 1 kg of chromic acid will produce 10 kg of sludge, and a large amount of sludge will be generated during the treatment process. The environmental problems caused by sewage discharge are prominent. Although the currently popularized anion and cation resin exchange method emphasizes zero discharge of wastewater recycling, the industry accepts it to a low degree, because the anion resin contains sodium chromate. When the concentration of chromic acid is high, the damage to the resin is great, and a large amount of pure water is required to clean the sodium chromate, and the accumulation of anode metal impurities is large, which makes the adsorption effect of the cation exchange resin worse, and frequent backwash regeneration wastes water resources , the sulfuric acid and caustic soda used for backwash regeneration have high purity requirements, and some treatment methods make sodium chromate and anode backwash sulfate into coatings, but this method requires a professional unified organization to process, and the obtained anode The concentration of the backwash solution is not high, and the amount is not large, resulting in relatively high transportation costs and high operating costs for the agent processing industry, making this method theoretically feasible, but practical operation is difficult, and it cannot be operated in a closed manner, and chromic acid cannot be used Reuse of waste water for regeneration, so existing enterprises would rather choose the chemical reduction neutralization precipitation method that has secondary pollution caused by sludge effluent.

Contents of the invention

The first technical problem to be solved by the present invention is to provide a chromic acid wastewater treatment method that discards a large amount of sludge, regenerates and reuses the chromic acid wastewater, and operates in a closed manner.

The second technical problem solved by the present invention is to provide a chromic acid wastewater treatment system using the above-mentioned chromic acid wastewater treatment method.

The technical scheme of the first technical problem solved by the present invention is: a kind of chromic acid wastewater treatment method, comprises the following steps:

A. Introduce the chromic acid wastewater produced by the production system into the anode resin tank equipped with cation exchange resin and the cathode resin tank equipped with anion exchange resin in sequence, and carry out ion exchange. The heavy metal ions and chromate ions in the chromic acid wastewater are eliminated. Adsorption, the chromic acid wastewater forms regenerated water, and the regenerated water is input into the regenerated water storage tank for recycling in the production system or for use in subsequent treatment processes;

B. When the exchange capacity of the cation exchange resin through ion exchange is close to or reaches saturation, stop inputting chromic acid waste water to the anode resin tank, and regenerate the cation exchange resin with a strong acid solution, when in the anode resin tank After the anode regeneration waste liquid is discharged, the regenerated water obtained in step A is used for backwashing, so that the cation exchange resin can be recycled for the next round after the exchange capacity is restored, and the regeneration and backwashing generated Anode regeneration waste liquid and anode backwash waste liquid are collected for treatment;

When the exchange capacity of the ion-exchanged anion exchange resin approaches or reaches saturation, stop inputting chromic acid waste water to the cathode resin tank, and regenerate the anion exchange resin with a strong alkaline solution. When the cathode in the cathode resin tank is regenerated After the waste liquid is discharged, carry out backwashing treatment with the regenerated water obtained in step A, and carry out the next round of recycling after the anion exchange resin is restored to the exchange capacity, and the cathode regeneration waste liquid and the cathode generated by the regeneration treatment and backwashing treatment are The backwash waste liquid is collected for treatment;

C. Put the anode regeneration waste liquid, anode backwash waste liquid, cathode regeneration waste liquid and cathode backwash waste liquid into the diaphragm electrolyzer for electrolysis treatment, and the high-concentration chromic acid mixed acid produced by electrolysis is purified and then input into the production system Recycling, the high-concentration alkaline solution generated by electrolysis is used for recycling when the anion exchange resin is regenerated;

The diaphragm electrolyzer in step C is divided into an outer tank and an inner tank by the ion diaphragm, the inner tank inside the ion diaphragm is the cathode, and the outer tank outside the ion diaphragm is the anode, and the anode regeneration waste liquid, anode backwash waste liquid, and cathode regeneration The waste liquid and cathode backwash waste liquid are input into the outer tank. Before electrolysis, regenerated water is added to the inner tank, and sodium hydroxide solution is injected into the regenerated water in the inner tank, so that the concentration of the sodium hydroxide solution in the inner tank reaches 1wt%. The liquid level of regenerated water in the inner tank is the same as that of the outer tank. The current density used for electrolysis is 2-5A/dm ² and the voltage is 15-30V. During the electrolysis reaction, the concentration of sodium hydroxide in the inner tank gradually increases. High, when the concentration of sodium hydroxide is greater than or equal to 4wt%, the sodium hydroxide solution in the inner tank is reduced in concentration: remove the sodium hydroxide solution in the part of the inner tank for the regeneration treatment process of the anion exchange resin in the step B to use, so The drop in liquid level caused by adding pure water or regenerated water to the cathode side is supplemented, so that the concentration of sodium hydroxide solution in the inner tank is reduced from 4wt% to 1wt%; the metal ion oxide deposited on the ion diaphragm is regularly removed; During electrolysis, chromic acid mixed acid is generated in the outer tank. As the concentration of chromic acid mixed acid increases, the high-concentration chromic acid mixed acid in the outer tank is regularly drawn out of the outer tank and purified, and then input into the production system for recycling. The anode water level When descending, input anode regeneration waste liquid, anode backwash waste liquid, cathode regeneration waste liquid and cathode backwash waste liquid for replenishment; the purification treatment in step C is: first stop anode regeneration waste liquid, anode backwash waste liquid, cathode regeneration The waste liquid and cathode backwash waste liquid enter the diaphragm electrolyzer, and then determine that the sodium ions are almost free to the cathode, which can be based on the current approaching zero, and then electrolyze the high concentration of the anode

The high-concentration chromic acid mixed acid produced by anode electrolysis is added to barium carbonate, stirred and then left to separate. The upper layer solution becomes pure chromic acid, which is returned to the production system for continued use.

The beneficial effect of the chromic acid wastewater treatment method of the present invention is: because the above-mentioned technical scheme adopts the combination of the anion and cation exchange method and the diaphragm electrolysis method, the chromic acid wastewater is ion-exchanged with the anion and cation exchange resins, so that the chromic acid wastewater becomes The regenerated water can be reused in the production system; in the regeneration and backwash subsequent treatment of anion and cation exchange resins, regenerated water is used instead of pure water in the prior art, which saves a large amount of equipment investment in pure water production and reduces The production cost makes a closed water cycle in the whole production process and the subsequent production process, reducing the waste of water resources: in the further follow-up treatment, the anode regeneration waste liquid, the anode backwash waste liquid, the cathode regeneration waste liquid and the cathode The backwash waste liquid is input into the diaphragm electrolyzer for electrolytic treatment. According to the characteristics that the dissociation of sodium ions is much greater than that of other metal ions, sodium ions can easily enter the cathode area under the condition of electrification, while metal ions with low dissociation such as Fe ³⁺ , Cr ⁶⁺ , Ca ²⁺ , etc. cannot pass through the ionic diaphragm of the diaphragm electrolytic cell and gather on the surface of the ionic diaphragm near the anode, forming oxides or hydroxides, which adhere to the side of the diaphragm near the anode, It is easy to remove by scraping; while the cathode on the side of the ion diaphragm near the cathode can electrolyze alkali smoothly, and the anode on the other side of the ion diaphragm can electrolyze acid. Sodium hydroxide, chromic acid, sulfuric acid and metal impurities can be easily separated by using the separation of the ion diaphragm, and the operation procedure is simple and the operation cost is low. The only precipitate produced is a small amount of sulfuric acid produced during the purification process Barium, it can be easily separated from chromic acid, and can also become a recycled product after precipitation, collection, and cleaning, without having to be discharged. Compared with the precipitation neutralization method in the prior art, 1 kg of chromic acid wastewater is processed to produce 10 The amount of kilogram of precipitation waste, the a small amount of barium sulfate that produces during purifying process seems negligible, makes the superiority of the present invention obvious; On the other hand, membrane electrolysis method has removed the follow-up problem that uses ion-exchange resin method to produce in the prior art: a, The high-concentration alkaline solution produced by electrolysis is used for recycling when the anion exchange resin is regenerated, which avoids the increase in production costs due to the high purity requirements of caustic soda used for backwash regeneration; it can also further increase the concentration of chromic acid, such as in the electroplating industry In the process, the concentration of chromic acid is increased to meet the concentration requirements of the electroplating tank so that it can be reused in the electroplating tank, so that the entire production process and subsequent production processes form a closed circulation of alkali solution and chromic acid solution, which is truly sealed. Circulating production, no need for external discharge; b. Avoiding the lack of high concentration of the anode backwash solution obtained in the prior art, which cannot be reused in the production system, and the amount is not large, but it is handled by a professional unified organization , resulting in relatively high transportation costs and high operating costs for the agency business. This scheme makes the production operation management process simple, as long as the sodium hydroxide solution in the inner tank is regularly reduced in concentration, the chromic acid mixed acid solution in the outer tank is regularly reduced in concentration, and the metal oxide attached to the ion diaphragm is regularly scraped off. It can be used as a substance or hydroxide, and there is no need to waste manpower to stay on the post.

During the electrolytic treatment, the reaction at the cathode on the side of the ion diaphragm close to the cathode is:

H ₂ O = 2H ⁺ +OH ^-

Na ⁺ +OH ^- ＝NaOH

The cathode is electrolyzed to produce alkali, which can be recycled for further use.

The reaction on the anode side of the ionic membrane is:

Fe ³⁺ +OH ^- ＝Fe(OH) ₃ ↓

Other metal cations such as iron deposit on the surface of the ion membrane on the anode side and can be periodically scraped off.

The reaction at the anode on the anode side of the ionic membrane is:

H ₂ O = 2H ⁺ +OH ^-

Cr ₂ O ₇ ^2- +H ⁺ ＝H ₂ Cr ₂ O ₇

SO ₄ ^2- +H ⁺ ＝H ₂ SO ₄

The chromic acid mixed acid produced by anode electrolysis can be added to the production system after purification to remove sulfuric acid and continue to be used.

The purification process in step C is to input the high-concentration chromic acid mixed acid produced by anode electrolysis into the purification tank, add barium carbonate, stir and then stand for separation, and take the upper layer solution and add it to the production system for continued use.

The purification reaction is:

BaCO3+H ₂ SO ₄ ＝BaSO ₄ ↓+H ₂ O+CO ² ↑

Sulfuric acid precipitates barium sulfate, which increases the purity of chromic acid.

The main chemical reaction in the ion exchange process between cation exchange resin and chromic acid wastewater is: Fe ³⁺ , Ni ²⁺ , Cu ²⁺ , Cr ⁶⁺ cations in chromic acid wastewater and cations in cation exchange resin undergo Exchange; the cation exchange reaction formula is as follows:

Fe ³⁺ +3RH＝FeR ₃ +3H ⁺

Ni ²⁺ +2RH＝NiR ₂ +2H ⁺

Cu ²⁺ +2RH＝CuR ₂ +2H ⁺

Cr ²⁺ +3RH＝CrR ₆ +6H ⁺

The cations in chromic acid wastewater are different in various production industries. For example, in the electroplating industry, it varies according to the material of the electroplating products. For example, if electroplating iron products, the cations in the electroplating chromic acid wastewater are mainly iron ions. When electroplating copper products, the cations in the electroplating chromic acid wastewater are mainly copper ions.

After cation exchange, the cations in the chromic acid wastewater enter the cation exchange resin, and the hydrogen in the cation resin enters the chromic acid wastewater, which reduces the pH value of the chromic acid wastewater. The pH value of chromic acid wastewater is further reduced by cation exchange, so that there are more H ⁺ in chromic acid wastewater to maintain the existence of Cr ₂ O ₇ ^2- ; in addition, lower pH value can also promote the chromic acid wastewater in When performing ion exchange with anion exchange resin anions, it is more conducive to the absorption of chromate anions. The main chemical reactions in the process of anion exchange in step A are: anions such as Cr ₂ O ₇ ^2- , CrO ₄ ^2- , CrO ₄ ^2- , SO ₄ ^2- in chromic acid wastewater and cations and anions in anion exchange resins Carry out exchange; Anion exchange reaction formula is as follows:

Cr ₂ O ₇ ^2- + ^2ROH ＝R ₂ Cr ₂ O ₇ +2OH-

CrO ₄ ^2- +2ROH ^＝ R ₂ CrO ₄ +2OH-

SO ₄ ^2- +2ROH ^＝ R ₂ SO ₄ +2OH-

It can be seen from the reaction that when the chromate anion is adsorbed, the exchange capacity of the same amount of anion exchange resin Cr ₂ O ₇ ^2- is twice the exchange capacity of CrO ₄ ^2- ,

As a specific scheme of the above-mentioned technical scheme, the step of regenerating the cation exchange resin in step B is specifically: adding a strong acid solution in the anode resin tank to be a sulfuric acid solution with a concentration of 1 to 4 wt%, soaking the cation exchange resin for more than 24 hours;

Or the step of regenerating the anion exchange resin in step B is specifically: adding a strong alkali solution to the cathode resin tank as a sodium hydroxide solution with a concentration of 1 to 4 wt%, and soaking the anion exchange resin for more than 24 hours;

The reaction of cation exchange resin regeneration is as follows:

2FeR ₃ +3H ₂ SO ₄ ＝Fe ₂ (SO ₄ ) ₃ +6RH

NiR ₂ +H ₂ SO ₄ =NiSO ₄ +2RH

CuR ₂ +H ₂ SO ₄ =CuSO ₄ +2RH

CrR ₆ +3H ₂ SO ₄ ＝Cr(SO ₄ ) ₃ +6RH

Anion exchange resin regeneration reaction is as follows:

R ₂ Cr ₂ O ₇ +2NaOH＝Na ₂ Cr ₂ O ₇ +2ROH

R ₂ CrO ₄ +2NaOH＝Na ₂ CrO ₄ +2ROH

R ₂ SO ₄ +2NaOH=Na ₂ SO ₄ +2ROH

The products produced by anion regeneration treatment are mainly Na ₂ Cr ₂ O ₇ and Na ₂ SO ₄ .

As a further improvement to the above technical solution, the soaking time is between 24 hours and 48 hours. This time length is more reasonable, even if the cation exchange resin regeneration or anion exchange resin regeneration is complete, it is controlled within the range of maximizing production efficiency.

As a further improvement to the above technical solution, the soaking time is between 24 hours and 48 hours. This time length is more reasonable, even if the cation exchange resin regeneration or anion exchange resin regeneration is complete, it is controlled within the range of maximizing production efficiency.

As a further improvement to the above technical solution, pure chromic acid is heated and concentrated to meet the concentration requirements of the production system.

The technical scheme of the second technical problem solved by the present invention is:

A chromic acid wastewater treatment system is used to treat the chromic acid wastewater produced by the production system, including:

Anode resin tank, the anode resin tank has a P set, P ≥ 1, each anode resin tank is connected in parallel, and the anode resin tank is equipped with a cation exchange resin for ion exchange with chromic acid wastewater and for regeneration of the cation exchange resin treatment and backwashing;

Cathode resin tank, the cathode resin tank has a Q set, Q≥1, each cathode resin tank is connected in parallel, and the cathode resin tank is equipped with anion exchange resin, which is used for ion exchange with chromic acid wastewater and for regeneration of anion exchange resin treatment and backwashing;

Regeneration and backwash waste water collection tank, used to collect the anode regeneration waste liquid and anode backwash waste liquid discharged from each anode resin tank, and also collect the cathode regeneration waste liquid and cathode backwash waste liquid discharged from each cathode resin tank , the liquid in the regeneration and backwash wastewater collection tank becomes mixed waste liquid;

A regenerated water storage tank for collecting the regenerated water discharged from each cathode resin tank;

The diaphragm electrolyzer is used for electrolytic treatment of the mixed waste liquid. The diaphragm electrolyzer includes a tank body, and the tank body is also provided with an ion diaphragm, which separates the tank body into an inner tank and an outer tank; the inner tank is equipped with A cathode plate, an anode plate is arranged in the outer tank; a purification tank, the liquid inlet of the purification tank is connected with the outer tank;

The cathodic regeneration liquid storage tank is used to store the strong alkali solution, the liquid outlet of the cathode regeneration liquid storage tank is respectively connected with each cathode resin tank, and the liquid inlet of the cathode regeneration liquid storage tank is connected with the inner tank;

An anode regeneration solution storage tank, used to store a strong acid solution, the outlet of the anode regeneration solution storage tank is respectively connected to each anode resin tank;

The liquid inlet of the production system is connected to the regenerated water storage tank and the purification tank respectively, and the liquid outlet of the chromic acid wastewater in the production system is connected to each anode resin tank respectively;

The liquid inlet of the regenerated water storage tank is respectively connected with each cathode resin tank; the liquid outlet of the regenerated water storage tank is also connected with the cathode resin tank, the anode resin tank and the inner tank respectively;

The liquid inlet of the regeneration and backwash wastewater collection tank is connected to each anode resin tank and each cathode resin tank respectively, and the liquid outlet is connected to the outer tank in the diaphragm electrolyzer;

The connections are all controllable connections equipped with pipeline valves, and there is a liquid level difference between each tank or a pump is provided.

The beneficial effects of the chromic acid wastewater treatment system of the present invention are: because the above-mentioned technical scheme adopts Q sets of cathode resin tanks and P sets of anode resin tanks, each of which is equipped with a controllable connection of pipeline valves in parallel, so that the operation of the system is only carried out by controlling the valves. The waste water treatment system is used together with the production system, and there is no need to carry out material transfer in each link, which saves manpower and reduces production costs.

The specific operation is as follows, when P=1, Q=1, the entire chromic acid wastewater treatment system operates intermittently, first start the pipeline valve connecting the chromic acid wastewater outlet of the production system to the anode resin tank, so that the chromic acid wastewater enters the anode Resin tank, and then enter the cathode resin tank, so that the chromic acid wastewater becomes regenerated water and then enters the regenerated water storage tank for standby; when the cation exchange resin and anion exchange resin are saturated or close to saturation, close the chromic acid wastewater outlet of the production system and the anode resin tank, and close the pipeline valve between the cathode resin tank and the regenerated water storage tank, and then open the pipeline valve between the liquid outlet of the anode regeneration solution storage tank and the anode resin tank, so that the anode regeneration solution storage tank is strong Alkali solution is input into the anode resin tank, and the valve is closed after reaching the liquid level height requirement, and the pipeline valve between the liquid outlet of the cathode regeneration solution storage tank and the cathode resin tank is opened, so that the strong acid solution in the cathode regeneration solution storage tank is input into the cathode resin tank , close the valve after reaching the liquid level height requirement, and regenerate the cation exchange resin and anion exchange resin. After emptying the anode regeneration waste liquid and the cathode regeneration waste liquid, open the pipe valve between the outlet of the regenerated water storage tank and the cathode resin tank and the anode resin tank, so that the regenerated water can be used for the cation exchange resin and anion exchange resin respectively. The resin is backwashed, and the generated anode backwash waste liquid and cathode backwash waste liquid continue to be discharged into the regeneration and backwash waste water collection tank. After the backwash is completed and the waste liquid is drained, the anode resin tank, cathode resin tank and regeneration and the pipeline valve between the liquid inlet of the backwash wastewater collection tank, start the pipeline valve connected to the chromic acid wastewater outlet of the production system and the anode resin tank, and carry out the next cycle of chromic acid wastewater treatment. Treatment of mixed waste liquid in the regeneration and backwash wastewater collection tank: open the pipeline valve between the outlet of the regeneration and backwash wastewater collection tank and the outer tank of the diaphragm electrolytic cell, so that the mixed waste liquid is input into the outer tank, and open the regenerated water storage The pipeline valve between the liquid outlet of the tank and the inner tank, input regenerated water into the inner tank, and inject sodium hydroxide solution into the regenerated water in the inner tank, so that the concentration of the sodium hydroxide solution in the inner tank reaches 1wt%. The height of the regenerated water level is consistent with the height of the outer tank liquid level; during the electrolysis reaction, the concentration of sodium hydroxide in the inner tank gradually increases, and when the concentration of sodium hydroxide is greater than or equal to 4wt%, the sodium hydroxide solution in the inner tank is reduced Concentration treatment: Open the pipeline valve between the inner tank and the liquid inlet of the cathode regeneration solution storage tank, so that the sodium hydroxide solution in the inner tank is partially input into the cathode regeneration solution storage tank, then close the valve, and open the inner tank and the regeneration water Pipeline valves between the storage tanks, regenerated water is added to the inner tank, so that the liquid level of the inner tank is maintained at the same height as the liquid level of the outer tank, and the concentration of the sodium hydroxide solution in the inner tank is reduced from 4wt% to 1wt%; Metal ion oxides on the diaphragm are removed; chromic acid mixed acid is generated in the outer tank during electrolysis, and when the concentration of the chromic acid mixed acid rises to a concentration that can be used in the electroplating tank, the pipeline valve between the outer tank and the purification tank is opened, Input the high-concentration chromic acid mixed acid in the outer tank into the purification tank and close the valve, then open the pipeline valve between the outlet of the regeneration and backwash wastewater collection tank and the outer tank, and input the mixed waste liquid to supplement and maintain the purity of the outer tank. The liquid level is consistent with the inner tank. After the high-concentration chromic acid mixed acid is purified, the pipeline valve between the liquid outlet of the purification tank and the liquid inlet of the production system is opened, and the purified high-concentration chromic acid is input into the production system for recycling. .

When P>1, Q>1, the operation of the chromic acid wastewater treatment system is basically the same as the above operation, the difference is that the Q set of cathode resin tanks and the P set of anode resin tanks are divided into two or more groups, each time The operation only starts the pipeline valve between one group of anode resin tank and cathode resin tank and the chromic acid wastewater outlet of the production system, and closes the pipeline valves between the other groups and the chromic acid wastewater outlet of the production system until it is started After the treatment of chromic acid wastewater reaches saturation or close to saturation, the group closes the pipeline valve to stop the entry of chromic acid wastewater, and at the same time starts the pipeline valve between the other groups and the chromic acid wastewater outlet of the production system, so that the rotation , so that when the group that is saturated or close to saturation is performing regeneration and backwashing, the system operates continuously for the treatment of chromic acid wastewater without intermittent operation.

As a further improvement to the above technical solution, it also includes a heating concentration tank, the liquid inlet and liquid outlet of the heating concentration tank are respectively connected in series with the liquid inlet of the purification tank and the production system. The improvement enables the chromic acid wastewater treatment system to adjust the concentration of pure chromic acid obtained from the purification tank, which can meet the requirements of the production system.

As a specific solution to the above technical solution, the tank body is a plastic tank body, the ion diaphragm is N purple sand tanks, N≥1, and the purple sand tanks have a volume of ^60-100L and a water permeability of 0.01-0.05ml/dm2 The purple sand cylinder with a sintering temperature of 1000-1200°C; the current density for electrolysis loaded between the anode plate and the cathode plate is 2-5A/dm ² , and the voltage is 15-30V; the cathode plate is a cylinder Shaped stainless steel cylinder, the anode plate is a chrome-plated lead plate, and the cylindrical stainless steel cylinder is covered with small holes that run through the cylinder wall in the radial direction. Because the purple sand cylinder contains a certain amount of quartz sand, it retains a certain degree of water permeability under high temperature sintering, and is more resistant to chromic acid corrosion than ordinary ceramics; even under long-term use, its water permeability remains unchanged; in multiple purple sand cylinders When connected and used, the current distribution is still uniform, which makes the electrolytic regeneration effect good. Because the cathode plate is made into a cylinder, it can achieve low current and uniform current distribution, so that the catholyte can dissociate to the anode in the form of chromate, and precipitate ferric chromate, so as to quickly and effectively remove metal impurities.

Description of drawings

Fig. 1 is the cathode sodium hydroxide concentration curve figure of embodiment two of the processing method of chromic acid wastewater of the present invention;

Fig. 2 is the cathode sodium hydroxide concentration curve figure of embodiment three of the processing method of chromic acid wastewater of the present invention;

Fig. 3 is the schematic block diagram of embodiment one of the treatment system of chromic acid wastewater of the present invention;

Fig. 4 is the structural representation of the chromic acid electrolysis diaphragm tank in the embodiment one of the processing system of the chromic acid wastewater of the present invention;

Fig. 5 is the front view of the cathode plate of the chromic acid electrolytic membrane cell in the embodiment one of the treatment system of the chromic acid wastewater of the present invention;

Figure 6 is a top view of Figure 5;

Fig. 7 is the schematic block diagram of embodiment two of the treatment system of chromic acid wastewater of the present invention;

Fig. 8 is a schematic block diagram of another state of Embodiment 2 of the chromic acid wastewater treatment system of the present invention.

detailed description

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Embodiment 1 of the treatment method of chromic acid wastewater of the present invention

First, the chromic acid wastewater is injected into the anode resin tank equipped with cation exchange resin for ion exchange, and then the chromic acid wastewater flowing out of the anode resin tank is injected into the cathode resin tank equipped with anion exchange resin, and the chromic acid wastewater becomes in line with the discharge standard When the exchange capacity of the ion-exchanged cation exchange resin is close to or reaches saturation, stop inputting chromic acid waste water to the anode resin tank, and use the cation exchange resin with a concentration of 1 to 4wt% The sulfuric acid solution soaks the cation exchange resin for more than 48 hours. At this time, the sulfuric acid solution becomes the anode regeneration waste liquid. The anode regeneration waste liquid is collected for treatment, and the cation exchange resin is backwashed with regenerated water, and the anode generated by the backwash is backwashed. The backwash waste liquid is collected for treatment; the cation exchange resin is recycled for the next round after the exchange capacity is restored.

After the exchange capacity of the anion exchange resin through ion exchange approaches or reaches saturation, stop inputting chromic acid wastewater to the cathode resin tank, and the anion exchange resin is soaked in a sodium hydroxide solution with a concentration of 1 to 4wt% to the cation exchange resin for the soaking time More than 48 hours, at this time, the sodium hydroxide solution has become the cathode regeneration waste liquid, and the cathode regeneration waste liquid is collected for treatment, and the anion exchange resin is backwashed with regenerated water, and the cathode backwash waste liquid produced by backwashing is collected for disposal. Treatment; the anion exchange resin is recycled for the next round after the exchange capacity is recovered.

The tank body of the diaphragm electrolytic cell is divided into an outer tank and an inner tank by two built-in ceramic cylinders with a volume of 60L each. The ceramic cylinder is used as an ion diaphragm, the inside of the ceramic cylinder is a cathode, and the outer tank outside the ceramic cylinder is an anode, which is used for electrolysis. The current density is 2-5A/dm ² , the voltage is 15-30V, and the temperature is 50°C.

Collect anode regeneration waste liquid, anode backwash waste liquid, cathode regeneration waste liquid and cathode backwash waste liquid together to form a mixed waste liquid, input the mixed waste liquid into the outer tank, add regenerated water into the ceramic tank, and put it in the ceramic tank NaoH solution is injected into the regenerated water in the ceramic tank so that the concentration of NaoH in the regenerated water in the ceramic tank is about 1wt%, and the liquid level of the regenerated water in the ceramic tank is consistent with the liquid level of the outer tank.

During the electrolytic reaction process, the concentration of sodium hydroxide in the ceramic cylinder gradually increases. When the concentration of sodium hydroxide is greater than or equal to 4wt%, the concentration of the sodium hydroxide solution in the ceramic cylinder is reduced: remove part of the sodium hydroxide solution in the ceramic cylinder for storage For standby, the drop in liquid level caused by adding regenerated water to the cathode side is supplemented, so that the concentration of sodium hydroxide solution in the ceramic cylinder is reduced from 4wt% to about 1wt%; the metal ion precipitate deposited on the outer wall of the ceramic cylinder is regularly Elimination; chromic acid mixed acid is generated in the outer tank during electrolysis, and when the concentration of chromic acid mixed acid rises to meet the requirements of the production system, the high-concentration chromic acid mixed acid in the outer tank is drawn out of the outer tank and purified. The purification process is Add high-concentration chromic acid mixed acid to barium carbonate, stir and leave to separate, the upper layer solution becomes pure chromic acid, and the pure chromic acid is returned to the production system for continued use, and when the anode water level drops, input mixed waste liquid to supplement; The sodium hydroxide solution removed from the tank is used in the regeneration process of the anion exchange resin in the first step.

Embodiment two of the treatment method of chromic acid wastewater of the present invention

This embodiment is basically the same as the first embodiment of the treatment method of chromic acid wastewater, the difference is that the electrolysis operation of the diaphragm electrolyzer: get the sodium chromate containing 10g/L in the cathode backwash solution 500L and put it into the outer part of the diaphragm electrolyzer Tank, add regenerated water into the ceramic tank, and inject 1% NaoH solution into the regenerated water in the ceramic tank. After titration analysis, the NaoH concentration is 6.33g/L. The liquid level of the regenerated water in the ceramic tank is consistent with that of the outer tank. Operation Conditions: Temperature: 50°C. Power on for electrolysis. During 120 hours of electrolysis, 240L of mixed waste liquid is added to the outer tank, and 40L of recycled water is added to the ceramic tank. As time goes by, the concentration of NaoH solution in the ceramic cylinder changes, and the corresponding list of the change value and electrolysis time is as follows:

time h Concentration g/L 0 6.33 8 6.5 16 8 twenty four 9.8 32 11.6 40 12.4 48 15.2 56 16.3 64 17.1 72 18 80 18.3 88 18.5 96 18.9 104 19.1 112 19.3 120 19.3 128 19.3

The resulting cathode sodium hydroxide concentration curve is shown in Figure 1.

At the beginning of electrolysis, the current was very small because the temperature was low. As the time of electrolysis increased, the temperature continued to rise. At the beginning, the concentration of sodium hydroxide in the ceramic cylinder was only 1%, but after 16 hours, the current increased rapidly, and The concentration of sodium hydroxide also increased sharply, but the current dropped significantly after 72 hours, and the increase rate of the concentration of sodium hydroxide also slowed down. After 96 hours, the current almost dropped to zero, and the bubbles produced by the cathode plate were also very small, which means The yin and yang poles have reached a state of balance.

Embodiment three of the treatment method of chromic acid wastewater of the present invention

This embodiment is basically the same as Embodiment 2 of the treatment method of chromic acid wastewater, the difference being that the electrolysis operation of the diaphragm electrolyzer: put 500 L of mixed waste liquid into the outer tank of the diaphragm electrolysis, and as time goes on, in the ceramic cylinder The concentration of the NaoH solution changes, and the corresponding list of the change value and the electrolysis time is as follows:

time h Concentration g/L8 --> 0 3.1 8 3.2 16 3.9 twenty four 4.5 32 5.2 40 5.7 48 6.4 56 6.8 64 7.2 72 7.5 80 7.8

88 8.2 96 8.6 104 8.8 112 8.9 120 9.1 128 9.3 136 9.3

The resulting cathode sodium hydroxide concentration curve is shown in Figure 2.

There are a lot of oxides attached to the outer wall of the ceramic cylinder. The analysis results are as follows:

Ca:6%Cu:1.2%

Si:4.1%Pb:1.0

Mg:2%Ni:400ppm

Cr:1.5%Zn:200ppm

Compared with the second embodiment of the treatment method of chromic acid wastewater, the biggest difference between this embodiment is that the outer wall of the ceramic cylinder in this embodiment produces a large amount of attachments, which can be easily scraped off.

The examples of the three chromic acid wastewater treatment methods show that only the ionization concentration of sodium hydroxide in the inner tank should be paid attention to during operation, and the concentration of sodium hydroxide in the inner tank can be detected to determine whether to perform the operation of reducing the concentration. When the sodium concentration exceeds 4%, do the operation of reducing the concentration of sodium hydroxide; the chromic acid mixed acid produced by the outer tank and the metal impurities attached to the outer wall of the ceramic cylinder do not need to be used as a reference for operation until the chromic acid mixed acid in the outer tank is reduced. The sulfuric acid concentration must be measured only when the concentration reaches the electroplatable concentration. In the present embodiment, when the concentration of chromic acid mixed acid reaches 20-50g/L or above, barium carbonate is used to reduce the sulfuric acid, and then the concentration equipment is used to increase the acidity of concentrated chromium, while the metal impurities It will be attached to the periphery of the ceramic cylinder.

Embodiment 1 of the treatment system of chromic acid wastewater of the present invention

Referring to Fig. 3, the production system in the present embodiment is an electroplating tank, a chromic acid wastewater treatment system, which is used to treat the chromic acid wastewater produced by the electroplating tank, including:

1 set of anode resin tank, the anode resin tank is equipped with cation exchange resin, used for ion exchange with chromic acid wastewater, and used for regeneration treatment and backwash treatment of cation exchange resin;

1 set of cathode resin tank, the cathode resin tank is equipped with anion exchange resin, which is used for ion exchange with chromic acid wastewater, and for regeneration and backwashing of anion exchange resin;

Regeneration and backwash waste water collection tank, used to collect anode regeneration waste liquid and anode backwash waste liquid discharged from the anode resin tank, and also collect cathode regeneration waste liquid and cathode backwash waste liquid discharged from the cathode resin tank, regeneration and backwash waste liquid The liquid in the waste water collection tank becomes mixed waste liquid;

The regenerated water storage tank is used to collect the regenerated water discharged from the cathode resin tank;

Diaphragm electrolyzer is used for electrolytic treatment of mixed waste liquid. Diaphragm electrolyzer includes a tank body, and an ion diaphragm is arranged in the tank body, and the ion diaphragm separates the tank body into an inner tank and an outer tank; a cathode plate is arranged in the inner tank , the outer tank is provided with an anode plate; referring to Fig. 4, the electrolytic cell body is an acid and alkali resistant plastic tank body 11, and the plastic tank body 11 is provided with a chrome-plated lead plate 12 as an anode plate; There are four purple sand cylinders 13 as diaphragms, and a cylindrical stainless steel cylinder 14 as a cathode plate is sheathed in the cylinder body of each purple sand cylinder 13 . The purple sand jar 13 is a purple sand jar with a volume of 60-100L, a water permeability of 0.01-0.05ml/dm for ² days, and a sintering temperature of 1000-1200°C. The current density for electrolysis loaded between the anode plate and the cathode plate is 2-5A/dm ² , and the voltage is 15-30V.

Referring to Fig. 5 and Fig. 6, the cylindrical stainless steel cylinder 14 is covered with small holes 141 penetrating the cylinder wall along the radial direction of the cylinder, and a cathode connection end 142 is provided on the inner wall of the cylinder. During use, the small hole 141 on the cylindrical stainless steel cylinder 14 can increase the contact area with the liquid, so that the inner and outer surfaces of the cylindrical stainless steel cylinder 14 all react with the liquid, and the chromate radicals produced in the cylindrical stainless steel cylinder 14 can pass through Small holes dissociate toward the anode to speed up electrolysis

Looking back at Figure 4, the liquid inlet of the purification tank is connected to the outer tank;

The cathode regeneration solution storage tank is used to store the strong alkali solution, the liquid outlet of the cathode regeneration solution storage tank is respectively connected with the cathode resin tank, and the liquid inlet of the cathode regeneration solution storage tank is connected with the inner tank;

Anode regeneration solution storage tank, used to store strong acid solution, the outlet of the anode regeneration solution storage tank is connected with the anode resin tank;

The liquid inlet of the production system is connected to the regenerated water storage tank, the chromic acid wastewater outlet of the electroplating tank is connected to the anode resin tank; the liquid inlet and outlet of the heating concentration tank are respectively connected to the purification tank and the liquid inlet of the production system Connect in series.

The liquid inlet of the regenerated water storage tank is connected with the cathode resin tank; the liquid outlet of the regenerated water storage tank is also connected with the cathode resin tank, the anode resin tank and the inner tank respectively;

The liquid inlet of the regeneration and backwash wastewater collection tank is connected with the anode resin tank and the cathode resin tank, and the liquid outlet is connected with the outer tank in the diaphragm electrolyzer;

The above connections are all controllable connections equipped with pipeline valves, and there is a liquid level difference between each tank or a pump is provided.

The specific operation is as follows, first start the pipe valve connecting the chromic acid wastewater outlet of the electroplating tank to the anode resin tank, so that the chromic acid wastewater enters the anode resin tank, and then enters the cathode resin tank, so that the chromic acid wastewater becomes recycled water and then enters the recycled water for storage When the cation exchange resin and anion exchange resin are saturated or close to saturation, close the pipeline valve connecting the chromic acid wastewater outlet of the electroplating tank to the anode resin tank, and close the pipeline valve between the cathode resin tank and the regenerated water storage tank , and then open the pipeline valve between the liquid outlet of the anode regeneration solution storage tank and the anode resin tank, so that the strong acid solution in the anode regeneration solution storage tank is input into the anode resin tank, close the valve after reaching the liquid level height requirement, and open the cathode regeneration solution The pipeline valve between the liquid outlet of the storage tank and the cathode resin tank allows the strong alkali solution in the cathode regeneration solution storage tank to enter the cathode resin tank, and closes the valve after reaching the liquid level height requirement, and the cation exchange resin and anion exchange resin are processed. Regeneration treatment, after the regeneration treatment is completed, open the pipeline valves between the anode resin tank, the cathode resin tank and the liquid inlet of the regeneration and backwash wastewater collection tank respectively, and after emptying the anode regeneration waste liquid and the cathode regeneration waste liquid, open the regeneration water The pipeline valves between the liquid outlet of the storage tank and the cathode resin tank and the anode resin tank allow the regenerated water to backwash the cation exchange resin and anion exchange resin respectively, and the generated anode backwash waste liquid and cathode backwash waste liquid continue to Drain into the waste water collection tank for regeneration and backwashing. After backwashing and emptying the waste liquid, close the pipeline valves between the anode resin tank, cathode resin tank and the liquid inlet of the waste water collection tank for regeneration and backwashing, and start the electroplating tank. The pipeline valve connecting the chromic acid wastewater outlet to the anode resin tank performs the next cycle of chromic acid wastewater treatment. Treatment of mixed waste liquid in the regeneration and backwash wastewater collection tank: open the pipeline valve between the outlet of the regeneration and backwash wastewater collection tank and the outer tank of the diaphragm electrolytic cell, so that the mixed waste liquid is input into the outer tank, and open the regenerated water storage The pipeline valve between the liquid outlet of the tank and the inner tank, input regenerated water into the inner tank, and inject sodium hydroxide solution into the regenerated water in the inner tank, so that the concentration of the sodium hydroxide solution in the inner tank reaches 1wt%. The height of the regenerated water level is consistent with the height of the outer tank liquid level; during the electrolysis reaction, the concentration of sodium hydroxide in the inner tank gradually increases, and when the concentration of sodium hydroxide is greater than or equal to 4wt%, the sodium hydroxide solution in the inner tank is reduced Concentration treatment: Open the pipeline valve between the inner tank and the liquid inlet of the cathode regeneration solution storage tank, so that the sodium hydroxide solution in the inner tank is partially input into the cathode regeneration solution storage tank, then close the valve, and open the inner tank and the regeneration water Pipeline valves between the storage tanks, regenerated water is added to the inner tank, so that the liquid level of the inner tank is maintained at the same height as the liquid level of the outer tank, and the concentration of sodium hydroxide solution in the inner tank is reduced from 4wt% to about 1wt%; The metal ion oxide on the ion diaphragm is removed; the chromic acid mixed acid is generated in the outer tank during electrolysis, and when the concentration of the chromic acid mixed acid rises to the concentration that can be used in the electroplating tank, the pipeline valve between the outer tank and the purification tank is opened , input the high-concentration chromic acid mixed acid in the outer tank into the purification tank and close the valve, then open the pipeline valve between the outlet of the regeneration and backwash wastewater collection tank and the outer tank, and input the mixed waste liquid to supplement and maintain the outer tank The liquid level of the tank is consistent with that of the inner tank. After the high-concentration chromic acid mixed acid is purified, open the valve between the liquid outlet of the purification tank and the liquid inlet of the heating and concentrating tank to further concentrate the purified high-concentration chromic acid, and then Open the pipeline valve between the liquid outlet of the heating concentration tank and the liquid inlet of the electroplating tank, and input the purified high-concentration chromic acid into the electroplating tank for recycling.

Embodiment two of the treatment system of chromic acid wastewater of the present invention

This embodiment is basically the same as Embodiment 1 of the treatment system for chromic acid wastewater. The difference is that, referring to FIG. 7, there are two sets of anode resin tanks, namely anode resin tank 1 and anode resin tank 2, and the two sets of anode resin tanks are parallel connection, there are two sets of cathode resin tanks, namely cathode resin tank 1 and cathode resin tank 2, and the two sets of cathode resin tanks are connected in parallel. The pipeline valve between the liquid ports closes the pipeline valve between the anode resin tank 2 and the cathode resin tank 2 and the chromic acid wastewater outlet of the electroplating tank. At this time, the cations in the anode resin tank 2 and the cathode resin tank 2 The exchange resin and anion exchange resin are backwashed or regenerated. After the backwash or regeneration is completed, they wait for the rotation replacement; until the exchange capacity of the cation exchange resin and anion exchange resin in the anode resin tank 1 and cathode resin tank 1 reaches saturation. or close to saturation, see Figure 8, close the pipeline valve between the anode resin tank 1 and the cathode resin tank 1 and the chromic acid wastewater outlet of the electroplating tank, stop the chromic acid wastewater from entering, and start the anode resin tank 2 and the cathode simultaneously. The pipe valve between the resin tank 2 and the chromic acid wastewater outlet of the electroplating tank, and backwash or regenerate the cation exchange resin and anion exchange resin of the anode resin tank 1 and cathode resin tank 1, so that the rotation is performed, When the saturated or nearly saturated anode resin tank 1 and cathode resin tank 1 are being regenerated and backwashed, the system does not need to stop the treatment of chromic acid wastewater.

Claims (7)

1. a chromic acid method of wastewater treatment, it is characterised in that, comprise the following steps:

A. the chromic acid waste water that production system produces is introduced anode resin groove that Zeo-karb is housed successively and it is equipped with in the cathode resin groove of anionite-exchange resin, carry out ion-exchange, heavy metal ion and chromate ion in described chromic acid waste water are adsorbed, described chromic acid waste water forms reuse water, described reuse water input reuse water storage tanks, recycles for production system or supplies in subsequent processes;

B. when the Zeo-karb through ion-exchange exchange capacity close to or after reaching capacity, stop inputting chromic acid waste water to described anode resin groove, and described Zeo-karb strong acid solution is carried out manipulation of regeneration, after the anode regeneration waste liquid in anode resin groove is discharged, back washing process is carried out with the reuse water obtained in steps A, making described Zeo-karb recover to carry out after exchange capacity, next takes turns recycles, and the anode regeneration waste liquid and the anode back washing waste collection that produce described manipulation of regeneration and back washing process are pending;

When the anionite-exchange resin through ion-exchange exchange capacity close to or after reaching capacity, stop inputting chromic acid waste water to described cathode resin groove, and described anionite-exchange resin strong base solution is carried out manipulation of regeneration, after the cathode regenerative waste liquid in cathode resin groove is discharged, back washing process is carried out with the reuse water obtained in steps A, making described anionite-exchange resin recover to carry out after exchange capacity, next takes turns recycles, and the cathode regenerative waste liquid and the negative electrode back washing waste collection that produce described manipulation of regeneration and back washing process are pending;

C. electrolysis treatment is carried out by described anode regeneration waste liquid, anode back washing waste liquid, cathode regenerative waste liquid and negative electrode back washing waste liquid input diaphragm sell, the high density chromic acid mixing acid that electrolysis produces inputs production system after carrying out purification process and carries out recycle, carries out cycling and reutilization when the high concentration basic solution that electrolysis produces is used for described anionite-exchange resin manipulation of regeneration, described diaphragm sell is divided into outer groove and inside groove by ion diaphragm, inside groove inside ion diaphragm is negative electrode, outer groove outside ion diaphragm is anode, described anode regeneration waste liquid, anode back washing waste liquid, cathode regenerative waste liquid and negative electrode back washing waste liquid input in described outer groove, before carrying out electrolysis, described reuse water is added toward described inside groove, and inject sodium hydroxide solution in the reuse water of described inside groove, the concentration of sodium hydroxide solution in described inside groove is made to reach 1wt%, reuse water liquid level in described inside groove is consistent with described outer groove liquid level, current density for electrolysis is 2��5A/d, voltage is 15��30V,

In electrolytic reaction process, in described inside groove, naoh concentration raises gradually, when naoh concentration is more than or equal to 4wt%, sodium hydroxide solution in described inside groove is fallen concentration process: move out of in the described inside groove of part sodium hydroxide solution for the regeneration process of the anionite-exchange resin in step B, the liquid level decline caused, by adding pure water or reuse water supplements to negative electrode side, makes the concentration of sodium hydroxide solution in described inside groove be reduced to about 1wt% from 4wt%; Regularly the metal ion oxide compound being deposited on ion diaphragm is rejected; During electrolysis, described outer groove generates chromic acid mixing acid, along with described chromic acid increasing mixed acid concentration raises, after regularly the high density chromic acid mixing acid in described outer groove being drawn described outer groove and carrying out purification process, input production system carries out recycle, inputs anode regeneration waste liquid, anode back washing waste liquid, cathode regenerative waste liquid and negative electrode back washing waste liquid and supplement during anode water level decreasing;

Purification process described in step C is the high density chromic acid mixing acid gone out by anode electrolysis, adds barium carbonate, standing separation after stirring, and upper solution becomes pure chromic acid, and described pure chromic acid is produced for defeated time the continuous use of System relays.

2. chromic acid method of wastewater treatment according to claim 1, it is characterised in that:

The step that Zeo-karb carries out in step B manipulation of regeneration is specially: to add strong acid solution in anode resin groove be concentration is the sulphuric acid soln of 1��4wt%, to Zeo-karb soak time more than 24 hours;

Or the step that anionite-exchange resin carries out in step B manipulation of regeneration is specially: to add strong base solution in cathode resin groove be concentration is the sodium hydroxide solution of 1��4wt%, to anionite-exchange resin soak time more than 24 hours.

3. chromic acid method of wastewater treatment according to claim 2, it is characterised in that: described soak time is little between 48 hours 24.

4. chromic acid method of wastewater treatment according to claim 1, it is characterised in that: described pure chromic acid is through the concentrated concentration requirement reaching production system of heating.

5. a chromic acid Waste Water Treatment, processes for chromic acid waste water production system produced, it is characterised in that, comprising:

Anode resin groove, described anode resin groove has P to overlap, P >=1, anode resin groove parallel join described in each, described anode resin groove, built with Zeo-karb, for carrying out ion-exchange with described chromic acid waste water, and processes for described Zeo-karb carries out manipulation of regeneration and back washing;

Cathode resin groove, described cathode resin groove has Q to overlap, Q >=1, cathode resin groove parallel join described in each, described cathode resin groove, built with anionite-exchange resin, for carrying out ion-exchange with described chromic acid waste water, and processes for described anionite-exchange resin carries out manipulation of regeneration and back washing;

Regeneration and back washing waste water collection tank, for collecting anode regeneration waste liquid and the anode back washing waste liquid that anode resin groove described in each is discharged, the liquid also collected in the cathode regenerative waste liquid and negative electrode back washing waste liquid, described regeneration and back washing waste water collection tank that cathode resin groove described in each discharges becomes mixed waste liquor;

Reuse water holding tank, for collecting the reuse water that cathode resin groove described in each is discharged;

Diaphragm sell, for described mixed waste liquor is carried out electrolysis treatment, described diaphragm sell comprises groove body, is also provided with ion diaphragm in described groove body, and groove body is divided into inside groove and outer groove by described ion diaphragm; Described inside groove is provided with negative plate, described outer groove is provided with positive plate;

Purifying groove, the fluid inlet of described purifying groove is connected with described outer groove;

Cathode regenerative liquid storage tanks, for storing strong base solution, the liquid outlet of described cathode regenerative liquid storage tanks is connected with cathode resin groove described in each respectively, and the fluid inlet of described cathode regenerative liquid storage tanks is connected with inside groove;

Anode regenerated liquid storage tanks, for storing strong acid solution, the liquid outlet of described anode regenerated liquid storage tanks is connected with anode resin groove described in each respectively;

The fluid inlet of described production system is connected with reuse water storage tanks, purifying groove respectively, and the chromic acid waste water liquid outlet of described production system is connected with each anode resin groove respectively;

The fluid inlet of described reuse water storage tanks is connected with each cathode resin groove described respectively; The liquid outlet of reuse water holding tank is also connected with described cathode resin groove, described anode resin groove, described inside groove respectively;

The fluid inlet of described regeneration and back washing waste water collection tank is connected with each anode resin groove, each cathode resin groove respectively, and liquid outlet is connected with the described outer groove of diaphragm sell;

The described controlled connection being connected and being and be equipped with pipeline valve, has liquid level difference or is provided with pump between described groove.

6. a kind of chromic acid Waste Water Treatment according to claim 5, it is characterised in that, also comprise heating thickener, fluid inlet, the liquid outlet of described heating thickener are connected in series with the fluid inlet of described purifying groove and described production system respectively.

7. a kind of chromic acid Waste Water Treatment according to claim 6, it is characterised in that,

Described groove body is plastic groove, and described ion diaphragm is N number of boccaro cylinder, N >=1, the boccaro cylinder that described boccaro cylinder to be volume be 60��100L, water-permeable are 0.01��0.05ml/d days, sintering temperature is 1000��1200 DEG C;

The current density for electrolysis loaded between described positive plate and negative plate is 2��5A/d, voltage is 15��30V;

Described negative plate is cylindrical stainless steel cylinder, and described positive plate is chromium plating stereotype;

Described cylindrical stainless steel cylinder is covered with the aperture radially running through barrel wall.