A recovery process for waste colored stripping solution

Abstract

The application provides a recovery treatment process of colored waste stripping solution, which can remove colored substances, metal ions and volatile acid in the waste stripping solution and recover a phosphorus-sulfur mixed acid solution which can be reused; the process is simple, easy to operate, low in treatment cost, wide in application range, and has a mixed acid recovery rate of more than 98%, effectively improving the recycling effect of resources, and comprises the following steps: 1) filtration: the colored waste stripping solution is introduced into a filter, and after filtration, is introduced into a reaction tank; 2) decolorization: an oxidizing decolorizing agent is added, and the decolorized stripping solution is obtained by stirring and reacting; 3) stripping: the decolorized stripping solution is introduced from the top of a stripping tower, is dispersed by a spraying head and then falls into the tower body, compressed air is heated by an air heater and then enters the bottom of the stripping tower, and the decolorized stripping solution is stripped; 4) resin adsorption: the stripped stripping solution is condensed by a condenser and then is transported to a resin adsorption system for adsorption, and a phosphorus-sulfur mixed acid recovery product is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial waste liquid treatment, in particular to a recovery treatment process for colored waste polishing liquid. BACKGROUND

[0002] Anodic oxidation surface treatment process mainly uses metal or alloy parts as anode, and forms an oxide film on the surface by electrolysis. The metal oxide film can change the surface state and performance, such as surface coloring, improving corrosion resistance, enhancing wear resistance and hardness, and protecting the metal surface. The oxide film has a large number of micropores, and the microporous film has strong adsorption capacity and can be colored into various beautiful colors. Therefore, anodic oxidation surface treatment process is often used in the production of various metal mobile phone cases or watch cases.

[0003] The existing waste polishing liquid treatment process, such as the invention patent CN112299635A discloses a "purification treatment method of chemical polishing waste liquid", which uses extraction to recover phosphorus-sulfur mixed acid in the polishing liquid. Although this process can realize the recovery treatment of waste polishing liquid, it has no removal capacity for colored substances and volatile acids in the waste liquid, and the application range is narrow. For example, the invention patent CN106430267A discloses "a resource recycling recovery method for aluminum polishing waste phosphoric acid liquid", which recovers aluminum from waste polishing liquid, but does not recover sulfuric acid and phosphoric acid, resulting in waste of resources, and a large amount of secondary hazardous waste is generated, which needs to be treated twice, resulting in complex treatment process. SUMMARY

[0004] In view of the problems that the existing waste polishing liquid is difficult to treat colored waste polishing liquid containing pigments, the application range is narrow, and the treatment process is complex and the resource recycling effect is poor, the present application provides a recovery treatment process for colored waste polishing liquid, which can remove colored substances, metal ions and volatile acids in the waste liquid, and recover reusable phosphorus-sulfur mixed acid solution. The process is simple, easy to operate, has low treatment cost, wide application range, and the recovery rate of mixed acid can reach more than 98%, effectively improving the resource recycling effect.

[0005] The present application adopts the following technical scheme: a recovery treatment process for colored waste polishing liquid, characterized in that it comprises the following steps:

[0006] 1) Filtration: pass the colored waste polishing liquid into a filter, and after filtration through the filter, enter a reaction tank;

[0007] 2) decolorization: adding an oxidative decolorizing agent into the reaction tank and stirring to obtain a decolorized effluent;

[0008] 3) stripping: inputting the decolorized effluent from the top of a stripping tower, and falling into the stripping tower body after being dispersed by a spray head, inputting compressed air from the bottom of the stripping tower after being heated by an air heater, and stripping the decolorized effluent;

[0009] 4) resin adsorption: condensing the stripped effluent to 25-35 DEG C by a condenser, and delivering to a resin adsorption system for adsorption to obtain a phosphorus-sulfur mixed acid recovery product.

[0010] Further features are:

[0011] In step 1), the filter is a ceramic filter;

[0012] In step 2), the oxidative decolorizing agent is 20-40 wt% hydrogen peroxide or 5-10 wt% sodium hypochlorite solution;

[0013] The volume ratio of the amount of the oxidative decolorizing agent to the colored waste effluent is 5:1000-15:1000, and the stirring reaction time is 30-60 min;

[0014] When the hydrogen peroxide is used as the oxidative decolorizing agent, heating is performed after adding the hydrogen peroxide and before entering step 3) stripping, the heating temperature is 50-100 DEG C, and the heating time is 10-30 min;

[0015] In step 3), the air heater heats the compressed air to 100-120 DEG C;

[0016] The compressed air is filtered clean air, and the pressure of the compressed air is 0.8-1.0 MPa;

[0017] In step 4), the resin in the resin adsorption system is a cation exchange resin, and countercurrent adsorption is used.

[0018] The beneficial effects of the present application are:

[0019] The application is firstly filtered by a filter to remove solid impurities in the waste liquid, then a decolorizing oxidizing agent is added to the solution to remove the color generated by organic dyes in the waste liquid, then a stripping tower is used to remove volatile acids in the waste liquid, and at the same time, the excess oxidizing agent can be decomposed and removed, finally, a resin adsorption system is used to remove metal ions in the waste liquid, so that the colored waste etching solution is treated, and clear and transparent phosphorus-sulfur mixed acid is recovered, the metal ion content of the obtained phosphorus-sulfur mixed acid is less than 10 ppm, the acid recovery rate can reach more than 98%, the waste etching solution can be reconfigured for use, not only the environmental pollution can be prevented, but also the waste can be recycled and reused; the process is simple, easy to operate, the treatment cost is low, the application range is wide, and the recycling effect of resources is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 The process flowchart of the application is shown.

[0021] Fig. 2 The process system structure schematic diagram of the application is shown. DETAILED DESCRIPTION

[0022] The colored waste etching solution containing phosphoric acid, sulfuric acid, volatile acid such as nitric acid and acetic acid, and aluminum and iron metal ions is taken as an example, and the application is further described in combination with the drawings and examples:

[0023] As shown in Figs. 1-2 , a colored waste etching solution recycling treatment process comprises the following steps:

[0024] 1) filtration: the colored waste etching solution is pumped from the waste liquid tank 1 into the filter 2, and then enters the reaction tank 3 after being filtered by the filter 2; preferably, the filter is a ceramic filter, which can effectively block the solid impurities in the waste liquid;

[0025] 2) decolorization: an oxidizing decolorizing agent is added to the reaction tank 3, and stirring reaction is carried out to obtain a decolorized etching solution; the oxidizing decolorizing agent is 20-40wt% hydrogen peroxide or 5-10wt% sodium hypochlorite solution; the volume ratio of the added amount of the oxidizing decolorizing agent to the colored waste etching solution is 5:1000-15:1000, and the stirring reaction time is 30-60min; when hydrogen peroxide is used as the oxidizing decolorizing agent, heating is carried out after the hydrogen peroxide is added and before step 3) stripping, the heating temperature is 50-100℃, and the heating time is 10-30min;

[0026] 3) stripping: the decolorized and thrown liquid is input from the top of the stripping tower 4, dispersed by the spray head 401 and then falls into the stripping tower 4, the compressed air is heated to 100-120°C by the air heater 8 and then enters from the bottom of the stripping tower 4, so as to strip the decolorized and thrown liquid; the compressed air is clean air after filtration, the pressure of the compressed air is 0.8-1.0 MPa, and volatile acids such as nitric acid and acetic acid can be removed;

[0027] 4) resin adsorption: the stripped liquid is condensed to 25-35°C by the condenser 5 and then delivered to the resin adsorption system 4 for adsorption, the resin in the resin adsorption system is cation exchange resin, and metal ions are removed by countercurrent adsorption; the phosphorus-sulfur mixed acid recovery product is obtained, and the phosphorus-sulfur mixed acid recovery product is input into the mixed acid tank 7 for storage, so that the phosphorus-sulfur mixed acid recovery product can be used after being re-dispensed.

[0028] Example 1

[0029] 1000L of colored waste liquid containing 40wt% phosphoric acid, 10wt% sulfuric acid, 0wt% nitric acid, 5000ppm of aluminum ions, 0ppm of iron ions and brown color is pumped from the waste liquid tank 1 to the ceramic filter 2, filtered and then input into the reaction tank 3, the stirring motor 301 of the reaction tank is turned on, 15L of 20wt% hydrogen peroxide is slowly added to the reaction tank, stirred for 60min, heated to 100°C, and then reacted for 10min at the temperature, then pumped from the top into the stripping tower 4, sprayed from the spray head 401 at the top of the stripping tower, and the 0.8MPa compressed air heated to 120°C by the air heater is input from the lower part of the stripping tower, the stripped liquid is input into the condenser 5, cooled water is input, the temperature of the liquid is reduced to 35°C, delivered to the resin adsorption system 4, treated by the cation exchange resin, and then the phosphorus-sulfur mixed acid recovery product is obtained, the phosphorus-sulfur mixed acid recovery product is input into the mixed acid tank 7 for storage, the phosphorus-sulfur mixed acid recovery product is sampled and detected, the color of the obtained phosphorus-sulfur mixed acid recovery product is clear and transparent, the content of aluminum ions is reduced to 96ppm, the content of hydrogen peroxide is 0wt%, and the acid recovery rate is 99.5%.

[0030] Example 2

[0031] 1000L of colored waste etching solution containing 55wt% phosphoric acid, 20wt% sulfuric acid, 0.5wt% nitric acid, 12000ppm of aluminum ions, 2500ppm of iron ions, and purple color was pumped from the waste liquid tank 1 to the ceramic filter 2, and then filtered into the reaction tank 3. The stirring motor 301 of the reaction tank was turned on, and 10L of 30wt% hydrogen peroxide was slowly added into the reaction tank. After stirring for 45min, the temperature was increased to 75℃, and the reaction was carried out at this temperature for 20min. Then, the solution was pumped from the top of the stripper 4, sprayed out through the spray head 401 at the top of the stripper, and 0.9MPa compressed air heated to 110℃ by an air heater was introduced from the lower part of the stripper. The stripped etching solution was introduced into the condenser 5, cooled water was introduced, the temperature of the etching solution was reduced to 30℃, and then the etching solution was transported into the resin adsorption system 4. After being treated by the cation exchange resin, the phosphorus-sulfur mixed acid recovery product was obtained, and the phosphorus-sulfur mixed acid recovery product was introduced into the mixed acid tank 7 for storage. The phosphorus-sulfur mixed acid recovery product was sampled and detected, and the obtained phosphorus-sulfur mixed acid was clear and transparent in color, the content of nitric acid was reduced to 0wt%, the content of iron ions was reduced to 42ppm, the content of aluminum ions was reduced to 107ppm, the content of hydrogen peroxide was 0wt%, and the acid recovery rate was 99.1%.

[0032] Example 3

[0033] 1000L of colored waste etching solution containing 70wt% phosphoric acid, 30wt% sulfuric acid, 1wt% nitric acid, 20000ppm of aluminum ions, 5000ppm of iron ions, and brown color was pumped from the waste liquid tank 1 to the ceramic filter 2, and then filtered into the reaction tank 3. The stirring motor 301 of the reaction tank was turned on, and 5L of 40wt% hydrogen peroxide was slowly added into the reaction tank. After stirring for 30min, the temperature was increased to 50℃, and the reaction was carried out at this temperature for 30min. Then, the solution was pumped from the top of the stripper 4, sprayed out through the spray head 401 at the top of the stripper, and 1.0MPa compressed air heated to 100℃ by an air heater was introduced from the lower part of the stripper. The stripped etching solution was introduced into the condenser 5, cooled water was introduced, the temperature of the etching solution was reduced to 25℃, and then the etching solution was transported into the resin adsorption system 4. After being treated by the cation exchange resin, the phosphorus-sulfur mixed acid recovery product was obtained, and the phosphorus-sulfur mixed acid recovery product was introduced into the mixed acid tank 7 for storage. The phosphorus-sulfur mixed acid recovery product was sampled and detected, and the obtained phosphorus-sulfur mixed acid was clear and transparent in color, the content of nitric acid was reduced to 0wt%, the content of iron ions was reduced to 51ppm, the content of aluminum ions was reduced to 125ppm, the content of hydrogen peroxide was 0wt%, and the acid recovery rate was 98.6%.

[0034] Example 4

[0035] 1000L of the colored waste etching solution containing 40wt% phosphoric acid, 10wt% sulfuric acid, 0wt% nitric acid, 5000ppm of aluminum ions, 0ppm of iron ions and brown color was pumped from the waste solution tank 1 to the ceramic filter 2, and then filtered into the reaction tank 3. The stirring motor 301 of the reaction tank was turned on, and 15L of 5wt% sodium hypochlorite solution was slowly added into the reaction tank. The reaction was continuously stirred for 60min, and then pumped from the top into the stripping tower 4, sprayed from the spray head 401 at the top of the stripping tower, and 0.8MPa compressed air heated to 120℃ by the air heater was introduced from the lower part of the stripping tower. The etching solution after stripping was introduced into the condenser 5, cooled water was introduced to reduce the temperature of the etching solution to 35℃, and then transported into the resin adsorption system 4. After the cation exchange resin treatment, the phosphorus-sulfur mixed acid recovery product was obtained, and the phosphorus-sulfur mixed acid recovery product was input into the mixed acid tank 7 for storage. The phosphorus-sulfur mixed acid recovery product was sampled and detected, and the obtained phosphorus-sulfur mixed acid was clear and transparent in color, the aluminum ion content was reduced to 101ppm, and the acid recovery rate was 99.3%.

[0036] Example 5:

[0037] 1000L of the colored waste etching solution containing 70wt% phosphoric acid, 30wt% sulfuric acid, 1wt% nitric acid, 20000ppm of aluminum ions, 5000ppm of iron ions and brown color was pumped from the waste solution tank 1 to the ceramic filter 2, and then filtered into the reaction tank 3. The stirring motor 301 of the reaction tank was turned on, and 5L of 10wt% sodium hypochlorite solution was slowly added into the reaction tank. The reaction was continuously stirred for 30min, and then pumped from the top into the stripping tower 4, sprayed from the spray head 401 at the top of the stripping tower, and 1.0MPa compressed air heated to 100℃ by the air heater was introduced from the lower part of the stripping tower. The etching solution after stripping was introduced into the condenser 5, cooled water was introduced to reduce the temperature of the etching solution to 25℃, and then transported into the resin adsorption system 4. After the cation exchange resin treatment, the phosphorus-sulfur mixed acid recovery product was obtained, and the phosphorus-sulfur mixed acid recovery product was input into the mixed acid tank 7 for storage. The phosphorus-sulfur mixed acid recovery product was sampled and detected, and the obtained phosphorus-sulfur mixed acid was clear and transparent in color, the nitric acid content was reduced to 0wt%, the iron ion content was reduced to 49ppm, the aluminum ion content was reduced to 130ppm, and the acid recovery rate was 98.3%.

[0038] Table I

[0039]

Claims

1. A process for the recovery of spent colouring bath, characterised in that: It comprises the following steps: 1) filtration: the colored waste pickling liquor is passed into a filter, and after filtration through the filter, it is passed into a reaction tank; 2) decolorization: an oxidative decolorizing agent is added to the reaction tank, and the reaction is stirred to obtain a decolorized pickling liquor; 3) stripping: the decolorized pickling liquor is input from the top of a stripping tower, dispersed by a spray head and then falls into the stripping tower body, compressed air is heated by an air heater and then input from the bottom of the stripping tower, and the decolorized pickling liquor is stripped; 4) resin adsorption: the pickling liquor after stripping is condensed to 25-35℃ by a condenser, and then delivered to a resin adsorption system for adsorption to obtain a phosphorus-sulfur mixed acid recovery product; In step 4), the resin in the resin adsorption system is a cation exchange resin, and countercurrent adsorption is used. The volume ratio of the amount of the oxidative decolorizing agent to the colored waste pickling liquor is 5:1000-15:1000, and the stirring reaction time is 30-60 min.

2. A process for the recovery of spent colouring bath according to claim 1, characterized in that: In step 1), the filter is a ceramic filter.

3. A process for the recovery of spent colouring bath according to claim 1, characterized in that: In step 2), the oxidative decolorizing agent is 20-40wt% hydrogen peroxide or 5-10wt% sodium hypochlorite solution.

4. A process for the recovery of spent colouring bath according to claim 3, characterized in that: When the hydrogen peroxide is used as the oxidative decolorizing agent, heating is performed after the hydrogen peroxide is added and before step 3) stripping, the heating temperature is 50-100℃, and the heating time is 10-30 min.

5. A process for the recovery of spent colouring bath according to claim 1, characterized in that: In step 3), the air heater heats the compressed air to a temperature of 100-120℃.

6. A process for the recovery of spent colouring bath according to claim 1, characterized in that: The compressed air is filtered clean air, and the pressure of the compressed air is 0.8-1.0MPa.

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