CN-119349792-B - Pretreatment method of palladium-containing wastewater

Abstract

The invention discloses a pretreatment method of palladium-containing wastewater. Firstly, palladium-containing wastewater cleaned by equipment after workshop production enters a raw water tank through a collecting tank, then is pumped into a pipeline mixer, is mixed with a flocculating agent, then is subjected to reaction precipitation through a vertical flow precipitator, is pumped into a tubular centrifuge for mud-water separation, metal palladium is recovered from the separated matters through modes such as drying and roasting, filtrate is concentrated and filtered through a ceramic membrane, produced water is recycled to a system, and concentrated water is returned to the front end after being further concentrated to a certain multiple.

Inventors

• YANG JIN
• CHEN YAN
• LIU SHUN
• LI YONGGANG
• YANG KUN
• WANG YUFAN
• YANG CHAOLONG
• LIU CHAOYU
• CUI JIANYU
• ZHANG BO

Assignees

• 湖北兴发环保科技有限公司

Dates

Publication Date

20260508

Application Date

20241009

Claims (3)

1. 1. A pretreatment method of palladium-containing wastewater is characterized in that a vertical flow precipitator, a tubular centrifuge and ceramic membrane filtration are adopted in sequence to realize wastewater purification treatment, and the pretreatment method comprises the following steps: (a) Collecting the palladium-containing wastewater produced in a workshop by adopting a collecting tank, wherein the palladium content in the palladium-containing wastewater is 40-60 mg/L, pH, the value is 6-9, and the turbidity is 25-40 NTU; (b) Feeding the palladium-containing wastewater into a vertical flow precipitator by a pump to precipitate, filtering and collecting palladium-containing suspended matters, wherein a flocculating agent is also added in the step (b), and the flocculating agent is a mixture of fatty alcohol polyoxyethylene ether phosphate and ferrous sulfate; The vertical flow precipitator is filled with anion exchange resin, wherein the anion exchange resin is 2, 3-epoxypropyl trimethyl ammonium chloride modified to polystyrene microsphere resin, the precipitation time of the vertical flow precipitator is 2-24h, and the surface load is less than 0.5m 3 /m 2 & h; (c) Dehydrating the precipitate in step (b) by a tube centrifuge; (d) And (C) conveying the filtrate obtained by dehydration and separation in the step (C) to a ceramic membrane circulation tank, then adopting a circulation pump to carry out ceramic membrane cross-flow filtration, enabling produced water to enter a produced water buffer tank, adopting large-flux cross-flow filtration in the ceramic membrane filtration mode, wherein the circulation flow is 10-20 times of the water inlet flow, and firing the ceramic membrane made of aluminum oxide and silicon dioxide at 800-900 ℃.
2. 2. The pretreatment method of palladium-containing wastewater according to claim 1, wherein the technical index of the palladium-containing wastewater is that the temperature is 20-30 ℃ and the water inflow is 2-3m 3 /d.
3. 3. The method for pretreating palladium-containing wastewater according to claim 1, wherein the tube centrifuge is a polytetrafluoroethylene separator.

Description

Pretreatment method of palladium-containing wastewater Technical Field The invention belongs to the field of palladium catalyst recycling, and particularly relates to a treatment method for recycling palladium-containing wastewater. Background The palladium catalyst (palladuium catalyst) is a catalyst which uses palladium metal as main active component, uses palladium black or palladium salt to be carried on carriers such as alumina, zeolite and the like, uses sodium, cadmium, lead and the like as cocatalysts, is frequently adopted in the chemical and chemical reaction process, and has the characteristics of high catalytic activity, strong selectivity, convenient catalyst preparation, small usage amount, capability of optimizing performance by changing and improving the manufacturing method and compounding with other metal or cocatalysts active components. The palladium catalyst is a main raw material for producing a catalyst carrier by hydrogen peroxide, and is generally stored in a solid particle form, and the palladium catalyst naturally drops to the lower part because the specific gravity of the palladium catalyst is heavier than that of water. In the process of using the palladium catalyst in each production, a small part of palladium is dissolved in water, if natural precipitation is directly adopted, the time is long, the palladium in the wastewater cannot be recycled, the palladium is directly used as sewage to discharge, the production consumption is high, meanwhile, the sewage treatment cost is increased, and the sewage treatment difficulty is increased. Disclosure of Invention Aiming at the technical problems, the invention provides a treatment method for recycling palladium-containing wastewater, which comprises the following specific steps: (1) Because palladium-containing wastewater contains a large amount of particulate impurities, the palladium-containing wastewater needs to be pretreated by adopting a vertical flow precipitator, and flocculant is added into a pipeline mixer to carry out full mixing sedimentation, so that the palladium content in the palladium-containing wastewater can be reduced to below 8ppm, and the produced water is sent to a produced water buffer tank for standby. (2) The water-containing sludge in the precipitator mud bucket is subjected to mud-water separation through a tube centrifuge, and the separated palladium mud is recovered. (3) The filtrate produced by the tube type centrifuge is sent to a ceramic membrane for concentration and filtration, then the large-flux circulating filtration is carried out by a ceramic membrane filtration circulating pump, the circulating flow is about 10-20 times of the water inflow, the ceramic membrane is cleaned once in 1-3 months, when the pressure difference of the ceramic membrane is obviously increased, back flushing is carried out, the flushing to the surface of the ceramic membrane is increased, and the scaling is prevented from being too fast in the filtration process. (4) The produced water (turbidity is less than 5 NTU) after ceramic membrane filtration enters a produced water buffer tank for standby, the concentrated water produced by filtration returns to a concentration tank again, is concentrated to about 10-20 times, and is discharged into a precipitator. The palladium-containing wastewater has the technical indexes of 20-30 ℃ of temperature, 2-3m < 3 >/d of water inflow, 6-9 of palladium content of 30-40 mg/L, pH value and 20-30 NTU of turbidity. And (3) adopting a lining PO material in the vertical flow precipitator in the pipeline mixer in the step (1). Although the water quality is slightly acidic, the temperature is normal temperature, and the flocculant is added to have certain viscosity and is easy to be adsorbed on the surface of non-smooth equipment, so that the liner PO material can be fully settled, and the flocculant is a mixture of fatty alcohol polyoxyethylene ether phosphate and ferrous sulfate. In some embodiments, the vertical flow settler of step (b) is filled with an anion exchange resin that is a resin modified with 2, 3-epoxypropyltrimethylammonium chloride to polystyrene microspheres. The anion exchange resin is prepared by epoxidizing the surface of polystyrene microsphere with epoxy chloropropane, ring-opening the epoxidized microsphere with 5% -15% sulfuric acid to obtain surface hydroxylated porous microsphere, and modifying 2, 3-epoxypropyl trimethyl ammonium chloride onto the hydroxyl on the microsphere surface. The tubular centrifuge is a separating cylinder made of polytetrafluoroethylene. And (3) the ceramic membrane filtration in the step (3) adopts automatic control, and the liquid level of the ceramic membrane circulation tank is stabilized by controlling the water flow rate of the ceramic membrane produced into the circulation tank. The ceramic membrane filter in the step (3) adopts a ceramic membrane which is prepared by firing materials such as aluminum oxide, silicon dioxide and th