Pretreatment device for palladium-containing wastewater

Abstract

The utility model discloses a pretreatment device for palladium-containing wastewater, which is characterized in that a collecting tank and a flocculation basin are respectively connected with a vertical precipitator through pipelines, and the bottom of the vertical precipitator is connected with a tubular centrifuge through a pipeline; the tubular centrifuge is connected with the circulating pump through a pipeline and then connected with the ceramic membrane filter, and the ceramic membrane filter is connected with the buffer tank through a pipeline. And the tubular centrifuge is connected with the ceramic membrane circulating tank through a pipeline and then is connected with the circulating pump. The method comprises the following steps: feeding palladium-containing wastewater generated after equipment cleaning after workshop production into a raw water tank through a collecting tank, pumping into a pipeline mixer by a pump, adding a flocculating agent for mixing, carrying out reaction precipitation by adopting a vertical flow precipitator, pumping the precipitate into a tubular centrifuge for mud-water separation, and recovering metal palladium from the separated substance in manners of drying, roasting and the like. Filtrate is concentrated and filtered through a ceramic membrane, produced water is recycled to a system, and concentrated water is further concentrated to a certain multiple and then is returned to the front end.

Description

Technical Field

[0001] The utility model belongs to the field of palladium catalyst recycling, and particularly relates to a treatment device for recycling palladium-containing wastewater. Background Art

[0002] Palladium catalyst is a catalyst with metallic palladium as the main active component, using palladium black or palladium salts loaded on carriers such as alumina and zeolite, and sodium, cadmium, lead and other salts as co-catalysts. It is a catalyst frequently used in chemical and industrial reaction processes and has the characteristics of high catalytic activity, strong selectivity, easy catalyst preparation, small usage amount, and can be optimized by changing and improving the manufacturing method and compounding with other metals or co-catalyst active components.

[0003] Palladium catalyst, the primary raw material for the catalyst carrier in hydrogen peroxide production, is typically stored in the form of solid particles. Because palladium catalyst is heavier than water, it naturally settles to the bottom. During each production process, a small amount of palladium dissolves in the water. Direct precipitation would take a long time and render the palladium in the wastewater unrecyclable. Direct discharge as wastewater would result in high production costs, increased wastewater treatment costs, and increased the difficulty of wastewater treatment. Summary of the Invention

[0004] In response to the above technical problems, the present invention provides a treatment device for recycling palladium-containing wastewater, which is as follows:

[0005] The pretreatment device for palladium-containing wastewater has a collection tank and a flocculation tank connected to a vertical sedimentation tank via pipelines, and the bottom of the vertical sedimentation tank is connected to a tubular centrifuge via pipelines;

[0006] The tubular centrifuge is connected to a circulation pump through a pipeline and then to a ceramic membrane filter, and the ceramic membrane filter is connected to a buffer tank through a pipeline.

[0007] The tubular centrifuge is connected to the ceramic membrane circulation tank through a pipeline and then connected to the circulation pump.

[0008] The upper part of the vertical sedimentator is connected to the collection tank through a pipeline.

[0009] The ceramic membrane circulation tank is connected to the side wall of the vertical precipitator through a pipeline; the top of the ceramic membrane filter is connected to the ceramic membrane circulation tank through a pipeline.

[0010] The bottom of the ceramic membrane filter is connected to the collection tank via a pipeline.

[0011] The process of using the above device is as follows

[0012] (1) Because palladium-containing wastewater contains a large amount of particulate impurities, it needs to be pre-treated in a vertical flow sedimentator. By adding flocculants in the pipeline mixer for sufficient mixing and sedimentation, the palladium content in the palladium-containing wastewater can be reduced to below 8 ppm, and the produced water is sent to the water production buffer tank for standby use.

[0013] (2) The water-containing sludge in the sedimentation hopper is separated into mud and water by a tubular centrifuge, and the separated palladium sludge is recovered.

[0014] (3) The filtrate produced by the tubular centrifuge is sent to the ceramic membrane for concentration filtration, and then the ceramic membrane filtration circulation pump is used for high-throughput circulation filtration. The circulation flow rate is about 10-20 times the inlet water flow rate. The ceramic membrane is cleaned once every 1-3 months. When the pressure difference of the ceramic membrane increases significantly, backwashing is performed to increase the flushing of the ceramic membrane surface to prevent scaling too quickly during the filtration process.

[0015] (4) The produced water (turbidity < 5 NTU) after being filtered by the ceramic membrane enters the produced water buffer tank for standby use, and the concentrated water produced by filtration returns to the concentration tank again, and after being concentrated to about 10-20 times, it is discharged into the precipitator.

[0016] The process indicators of the palladium-containing wastewater are as follows: temperature 20~30℃, water inlet 2-3m³ / d, palladium content 30-40 mg / L, pH value 6~9, and turbidity 20-30 NTU.

[0017] The vertical flow sedimentation vessel in the pipeline mixer in step (1) is lined with PO material. Although the water quality is slightly acidic and the temperature is room temperature, the PO material lining can fully settle the water because the added flocculant has a certain viscosity and is easily adsorbed on the rough surface of the equipment. The flocculant is a mixture of fatty alcohol polyoxyethylene ether phosphate and ferrous sulfate.

[0018] In some embodiments, the vertical flow sedimentation vessel in step (b) is filled with an anion exchange resin, and the anion exchange resin is a resin modified with 2,3-epoxypropyltrimethylammonium chloride onto polystyrene microspheres.

[0019] The anion exchange resin is a polystyrene microsphere whose surface is epoxidized with epichlorohydrin, and then the epoxidized microspheres are subjected to a ring-opening reaction with 5%~15% sulfuric acid to obtain surface hydroxylated porous microspheres; 2,3-epoxypropyltrimethylammonium chloride is then modified on the hydroxyl groups on the microsphere surface to obtain an anion exchange resin.

[0020] The tubular centrifuge is a separation cylinder made of polytetrafluoroethylene.

[0021] The ceramic membrane filtration described in step (3) is automatically controlled to stabilize the liquid level of the ceramic membrane circulation tank by controlling the flow rate of the ceramic membrane water produced into the circulation tank.

[0022] The ceramic membrane filter in step (3) is a ceramic membrane made of materials such as aluminum oxide and silicon dioxide and fired at 800-900°C. It has high mechanical strength, can withstand a variety of environments, and is cost-effective.

[0023] The ceramic membrane filtration described in step (3) adopts high-flux circulation filtration, and its circulation flow rate is 10-20 times the feed amount; the use of high-flux circulation filtration mainly increases the flow rate of wastewater through the membrane surface of the ceramic membrane, thereby greatly reducing the residence time of muddy water on the membrane surface, thereby extending the fouling cycle and reducing the cleaning frequency.

[0024] According to the technical solution of the utility model, the impregnation wastewater from the catalyst workshop enters the raw water tank for storage, is pumped to the precipitator, and is precipitated in the precipitator by adding a flocculant. The muddy water after precipitation is discharged to the tubular centrifuge through the bottom valve for mud-water separation, the palladium mud is dried and roasted to remove impurities, and the palladium catalyst is recycled. The produced water is further filtered through a ceramic membrane and reused, and the concentrated water is returned to the front stage for further treatment, thereby improving the recovery efficiency and reducing the use cost of the palladium catalyst. The turbidity of the produced water is reduced to within 0.2 NTU. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural diagram of the utility model, which includes a collecting tank 1, a vertical sedimentation tank 2, a flocculation tank 3, a tubular centrifuge 4, a ceramic membrane circulation tank 5, a ceramic membrane filter 6, a circulation pump 7, and a buffer tank 8. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the embodiments. However, the scope of protection claimed by the present invention is not limited to the scope described in the embodiments.

[0027] Example 1

[0028] The pretreatment device for palladium-containing wastewater comprises a collecting tank 1 and a flocculation tank 3 connected to a vertical sedimentation vessel 2 via pipelines, and the bottom of the vertical sedimentation vessel 2 is connected to a tubular centrifuge 4 via a pipeline;

[0029] The tubular centrifuge 4 is connected to a circulation pump 7 via a pipeline and then connected to a ceramic membrane filter 6 , and the ceramic membrane filter 6 is connected to a buffer tank 8 via a pipeline.

[0030] The tubular centrifuge 4 is connected to the ceramic membrane circulation tank 5 through a pipeline and then connected to the circulation pump 7.

[0031] The upper part of the vertical sedimentation vessel 2 is connected to the collecting tank 1 via a pipeline.

[0032] The ceramic membrane circulation tank 5 is connected to the side wall of the vertical precipitator 2 via a pipeline; the top of the ceramic membrane filter 6 is connected to the ceramic membrane circulation tank 5 via a pipeline.

[0033] The bottom of the ceramic membrane filter 6 is connected to the collection tank 1 through a pipeline.

[0034] Example 2

[0035] Step (1): Use a water tank to receive palladium-containing wastewater provided by an upstream production unit, with the water quality being a palladium content of 40 mg / L, a pH value of 6-9, a turbidity of 30 NTU, and a temperature of 28°C;

[0036] Step (2): 3 m³ / d of water is fed into the vertical sedimentation vessel for precipitation, and a flocculant is added (the flocculant is a mixture of fatty alcohol polyoxyethylene ether phosphate and ferrous sulfate in a mass ratio of 10:1). The vertical flow sedimentation vessel is settling for 12 h, and the surface load is 0.4 m 3 / m 2 h, reducing the turbidity to 5 NTU and the palladium content in the palladium-containing wastewater to 5 ppm; the resulting produced water enters the palladium-containing wastewater in the collection tank;

[0037] Step (3): The obtained precipitate (water-containing sludge) is dehydrated and separated by a tubular centrifuge, and then circulated and filtered through a ceramic membrane filter (made of fired aluminum oxide) (the ceramic membrane filtration adopts a large-flux cross-flow filtration method with a circulated filtration flow rate of 24 m³ / d). The turbidity of the produced water is reduced to 0.2 NTU, and the palladium content in the palladium-containing wastewater is reduced to 0.8 ppm.

[0038] Step (4): The clean water after the treatment in step (3) enters the water production buffer tank for standby use and is subsequently used for workshop cleaning water reuse. After the concentrated water is concentrated to about 10-20 times, it is separated into mud and water by a tubular centrifuge and the sludge is recovered. The clean water continues to undergo the front-end sedimentation treatment.

[0039] Example 3

[0040] Step (1): Use a water tank to receive palladium-containing wastewater provided by an upstream production unit, with the water quality being a palladium content of 55 mg / L, a pH value of 7-9, a turbidity of 60 NTU, and a temperature of 26°C;

[0041] Step (2): 3 m³ / d of water is fed into a vertical sedimentation vessel for sedimentation. The vertical sedimentation vessel is filled with anion exchange resin. The sedimentation time of the vertical sedimentation vessel is 5 h and the surface load is 0.3 m 3 / m 2 h, reducing the turbidity to 3 NTU and the palladium content in the palladium-containing wastewater to 1 ppm; the resulting produced water enters the palladium-containing wastewater in the collection tank;

[0042] Anion exchange resin: refer to the preparation method of Example 1 of a preparation method for a high-temperature resistant strong alkaline anion exchange resin (202311464121.7).

[0043] Step (3): The obtained precipitate (water-containing sludge) is dehydrated and separated by a tubular centrifuge, and then circulated and filtered through a ceramic membrane filter (made of fired aluminum oxide) (the ceramic membrane filtration adopts a large-flux cross-flow filtration method with a circulated filtration flow rate of 24 m³ / d). The turbidity of the produced water is reduced to 0.05 NTU, and the palladium content in the palladium-containing wastewater is reduced to 0.09 ppm.

[0044] Step (4): The clean water after the treatment in step (3) enters the water production buffer tank for standby use and is subsequently used for workshop cleaning water reuse. After the concentrated water is concentrated to about 10-20 times, it is separated into mud and water by a tubular centrifuge and the sludge is recovered. The clean water continues to undergo the front-end sedimentation treatment.

Claims

1. A pretreatment device for palladium-containing wastewater, characterized in that: The collecting tank (1) and the flocculation tank (3) are respectively connected to the vertical sedimentation vessel (2) via pipelines, and the bottom of the vertical sedimentation vessel (2) is connected to the tubular centrifuge (4) via a pipeline; The tubular centrifuge (4) is connected to the circulation pump (7) via a pipeline and then connected to the ceramic membrane filter (6). The ceramic membrane filter (6) is connected to the buffer tank (8) via a pipeline.

2. The pretreatment device for palladium-containing wastewater according to claim 1, wherein The tubular centrifuge (4) is connected to the ceramic membrane circulation tank (5) through a pipeline and then connected to the circulation pump (7).

3. The pretreatment device for palladium-containing wastewater according to claim 1, wherein The upper part of the vertical sedimentation vessel (2) is connected to the collection tank (1) via a pipeline.

4. The pretreatment device for palladium-containing wastewater according to claim 2, wherein The ceramic membrane circulation tank (5) is connected to the side wall of the vertical precipitator (2) via a pipeline; and the top of the ceramic membrane filter (6) is connected to the ceramic membrane circulation tank (5) via a pipeline.

5. The pretreatment device for palladium-containing wastewater according to claim 1, characterized in that, The bottom of the ceramic membrane filter (6) is connected to the collection tank (1) via a pipeline.

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