Pretreatment system for membrane concentration of iron phosphate wastewater

Abstract

The utility model discloses a pretreatment system for iron phosphate wastewater membrane concentration. The pretreatment system comprises an adjusting tank, a pipeline type mixer, a neutralization reaction tank, a flocculation reaction tank, a sedimentation tank, an intermediate water tank, a multi-medium filter and a self-cleaning filter which are sequentially arranged in the flowing direction of iron phosphate wastewater, sludge in the sedimentation tank enters a plate-and-frame filter press through a sludge concentration tank; the neutralization reaction tank, the flocculation reaction tank and the sedimentation tank are integrated communication equipment, ammonia water is added into the neutralization reaction tank to enable the pH value to be 2-3, and PAC and PAM are added into the flocculation reaction tank. According to the utility model, most suspended matters can be removed by neutralizing, flocculating and clarifying the iron phosphate wastewater, and finally, produced water reaches the water inlet standard of membrane concentration, so that a guarantee is provided for subsequent evaporation and crystallization of monoammonium phosphate concentrated liquor to achieve the purpose of waste salt recovery.

Description

Technical Field

[0001] The utility model relates to the technical field of high-salt chemical wastewater, in particular to a pretreatment system for ferric phosphate wastewater membrane concentration. Background Art

[0002] With the rapid development of new energy technologies, the market demand for lithium iron phosphate batteries has increased dramatically, and so has the demand for its raw material, iron phosphate. However, the production of iron phosphate generates an increasing amount of high-salinity wastewater. Currently, high-salinity wastewater is primarily treated using a combination of membrane concentration and evaporative crystallization, with the goal of achieving zero high-salinity wastewater discharge and recycling waste salt resources.

[0003] To reduce flushing frequency and clogging risks during membrane treatment, it's necessary to reduce SS and hardness in the pretreatment stage. Traditional membrane concentration pretreatment often employs a dual-alkali process using sodium carbonate and sodium hydroxide. However, this treatment method still presents the following issues: First, the resulting sodium sulfate and sodium phosphate cannot be effectively utilized, resulting in resource waste and high hazardous waste disposal costs. Second, this method requires extensive equipment, occupies a large area, and increases investment and operating costs. Utility Model Content

[0004] In order to solve the above-mentioned problems, the present invention provides a pretreatment system for membrane concentration of iron phosphate wastewater.

[0005] To achieve the above-mentioned purpose, the utility model provides a pretreatment system for membrane concentration of ferric phosphate wastewater, comprising a regulating tank, a pipeline mixer, a neutralization reaction tank, a flocculation reaction tank, a sedimentation tank, an intermediate water tank, a multi-media filter, and a self-cleaning filter, which are sequentially arranged along the flow direction of the ferric phosphate wastewater; the sludge in the sedimentation tank enters a plate and frame filter press through a sludge concentration tank;

[0006] The neutralization reaction tank, the flocculation reaction tank and the sedimentation tank are integrated communication equipment. Ammonia water is added to the neutralization reaction tank to make the pH value 9-10, and PAC and PAM are added to the flocculation reaction tank.

[0007] Preferably, the rear end of the regulating tank is connected to a pipeline mixer, and the pipeline mixer is a static spiral mixer.

[0008] Preferably, the water outlet of the pipeline mixer is connected to the neutralization reaction tank, a partition is provided between the neutralization reaction tank and the flocculation reaction tank, and a through hole is provided at the bottom end of the partition, and the top of the flocculation reaction tank is connected to the top of the sedimentation tank.

[0009] Preferably, the overflow port at the upper end of the sedimentation tank is connected to the intermediate water tank.

[0010] Preferably, the intermediate water pool is connected to the top of the multi-media filter, and the multi-media filter is provided with cobblestone, quartz sand and activated carbon in sequence from top to bottom.

[0011] Preferably, a terminal end of the multimedia filter is communicated with the self-cleaning filter.

[0012] Preferably, the sludge thickening tank is connected to the bottom of the sedimentation tank, and a sludge scraper is provided in the sludge thickening tank.

[0013] Preferably, the scraper conveys the sludge to the plate and frame filter press through a discharge port.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] The utility model can remove most of the suspended matter by neutralizing, flocculating and clarifying the iron phosphate wastewater, and finally achieve the water production meeting the water inlet standard of membrane concentration, which provides a guarantee for the subsequent evaporation and crystallization of monoammonium phosphate concentrated solution to achieve the purpose of waste salt recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a pretreatment system for ferric phosphate wastewater membrane concentration according to the present invention. DETAILED DESCRIPTION

[0017] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0018] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0020] The following is combined with Figure 1 The utility model is further described in detail:

[0021] Reference Figure 1 The utility model provides a pretreatment system for membrane concentration of iron phosphate wastewater, comprising a regulating tank 1, a pipeline mixer 2, a neutralization reaction tank 3, a flocculation reaction tank 4, a sedimentation tank 5, an intermediate water tank 6, a multi-media filter 7, and a self-cleaning filter 8, which are arranged in sequence along the flow direction of the iron phosphate wastewater; the sludge in the sedimentation tank 5 enters a plate and frame filter press 10 through a sludge concentration tank 9;

[0022] The neutralization reaction tank 3 , the flocculation reaction tank 4 and the sedimentation tank 5 are integrated interconnected equipment. Ammonia water is added to the neutralization reaction tank 3 to adjust the pH value to 9-10, and PAC and PAM are added to the flocculation reaction tank 4 .

[0023] In this embodiment, the regulating tank 1 is connected to the wastewater of the iron phosphate production workshop, and mainly plays the role of homogenization and equalization; the regulating tank 1 pumps the wastewater in the regulating tank 1 to the pipeline mixer 2 through a water pump and a pipeline. The pipeline mixer 2 is a static spiral mixer, which further enhances the mixing effect.

[0024] Furthermore, the water outlet of the pipeline mixer 2 is connected to the neutralization reaction tank 3 through a pipeline. A partition is provided between the neutralization reaction tank 3 and the flocculation reaction tank 4 and a through hole is provided at the bottom end of the partition. The top of the flocculation reaction tank 4 is connected to the top of the sedimentation tank 5.

[0025] In this embodiment, the neutralization reaction tank 3 and the flocculation reaction tank 4 may be provided with baffles, which increase the residence time and reduce the connection between the pump and the water pipe. The pH value of the water entering the neutralization tank is 2-3, and the pH value is adjusted by adding ammonia water. PAC and PAM are added to the effluent in the flocculation reaction tank 4 to produce flocculated sludge, and then connected to the sedimentation tank 5.

[0026] Furthermore, the overflow port at the upper end of the sedimentation tank 5 is connected to the intermediate water pool 6 through a pipeline, and the intermediate water pool 6 is connected to the top of the multi-media filter 7 through a water pump and a pipeline. The operation of the water pump causes the supernatant in the sedimentation tank 5 to be pumped to the top of the multi-media filter 7 through the intermediate water pool 6, and passes through the goose soft stone, quartz sand and activated carbon from top to bottom in turn, and then is connected to the self-cleaning filter 8, which can remove most of the suspended matter.

[0027] In this embodiment, the sludge thickening tank 9 is connected to the bottom of the sedimentation tank 5. Coagulant aids can be added as needed to further reduce the water content of the sludge. A scraper is provided in the sludge separation area in the middle to transport the precipitated sludge to the sludge discharge port and then filter it through the plate and frame filter press 10.

[0028] The utility model realizes efficient pretreatment of ferric phosphate wastewater membrane concentration by arranging a regulating tank 1, a pipeline mixer 2, a neutralization reaction tank 3, a flocculation reaction tank 4, a sedimentation tank 5, an intermediate water tank 6, a multi-media filter 7, a self-cleaning filter 8, a sludge concentration tank 9 and a plate and frame filter press 10. Moreover, by using an integrated device for neutralization, flocculation and precipitation, the equipment investment cost is saved while also saving the floor space, thereby realizing an effective combination of social value and economic value. The utility model realizes efficient pretreatment of ferric phosphate wastewater membrane concentration, and by using an integrated device for neutralization, flocculation and precipitation, the equipment investment cost is saved while also saving the floor space, thereby realizing an effective combination of social value and economic value.

[0029] The utility model can remove most of the suspended matter by neutralizing, flocculating and clarifying the iron phosphate wastewater, and finally achieve the water production meeting the water inlet standard of membrane concentration, which provides a guarantee for the subsequent evaporation and crystallization of monoammonium phosphate concentrated solution to achieve the purpose of waste salt recovery.

[0030] Example:

[0031] The TDS of the iron phosphate wastewater in this embodiment is usually more than 50000 mg / L, and the cations are mainly Ca 2+ Mg 2+ 、Fe 3 + 、Mn 2+ etc. metal ions, and the anions are mainly SO 42 - and PO 43 - and a small amount of Cl-. Due to the high suspended matter and hardness, without pretreatment, the reverse osmosis membrane will be scaled and blocked, reducing the water production efficiency and the service life of the membrane, so the pretreatment requirements are relatively high.

[0032] The system comprises a regulating tank 1, a pipeline mixer 2, a neutralization tank 3, a flocculation tank 4, a sedimentation tank 5, an intermediate water tank 6, a multi-media filter 7, and a self-cleaning filter 8, arranged sequentially along the flow path of the ferric phosphate wastewater. The sludge from the sedimentation tank 5 flows through a sludge thickening tank 9 and enters a plate-and-frame filter press 10. The regulating tank 1 receives wastewater from the ferric phosphate production workshop, primarily serving to homogenize and balance the flow. The downstream pipeline mixer 2 utilizes a static spiral mixer to further enhance mixing. The neutralization tank 3, flocculation tank 4, and sedimentation tank 5 are integrated and interconnected. Natural flow is achieved through gravity, with baffles increasing residence time and reducing the need for pump and pipe connections. The pH of the influent to the neutralization tank is set at 2-3, adjusted by the addition of ammonia. The effluent is treated with PAC and PAM in the flocculation tank 4 to produce flocculated sludge, which is then connected to the sedimentation tank 5. By adding ammonia water, the pH value of the iron phosphate wastewater in the neutralization tank can be adjusted to 9-10. Since the main cations in the iron phosphate wastewater are ammonium salts and some metal ions, adding ammonia water does not introduce new ions, which makes the Ca in the wastewater 2+ Mg 2+ 、Fe 3+ 、Mn 2+ Metal ions such as iodine and iodine can produce precipitation, which can effectively remove CCa from wastewater 2+ Mg 2+ 、Fe 3+ 、Mn 2+ The effluent from the overflow port at the top of the sedimentation tank 5 is connected to the intermediate water tank 6 at the rear end. It then passes through a multi-media filter 7 composed of cobblestone, quartz sand, and activated carbon, and finally to a self-cleaning filter 8, which removes most suspended solids. The sludge thickening tank 9 is connected to the bottom of the sedimentation tank 5. Coagulant aids can be added as needed. If the sludge settling effect does not meet the requirements, a coagulant aid (PAM) can be added to the sludge thickening tank 9 through the dosing port. The concentration of PAM is preferably 0.1%. To further reduce the moisture content of the sludge, a sludge scraper is installed in the central sludge separation zone to transport the settled sludge to the sludge discharge port for filtration through a plate and frame filter press 10.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A pretreatment system for ferric phosphate wastewater membrane concentration, characterized in that: It includes a regulating tank, a pipeline mixer, a neutralization reaction tank, a flocculation reaction tank, a sedimentation tank, an intermediate water tank, a multi-media filter, and a self-cleaning filter arranged in sequence along the flow direction of the iron phosphate wastewater; the sludge in the sedimentation tank enters the plate and frame filter press through the sludge thickening tank; The neutralization reaction tank, the flocculation reaction tank and the sedimentation tank are integrated communication equipment. Ammonia water is added to the neutralization reaction tank to make the pH value 9-10, and PAC and PAM are added to the flocculation reaction tank.

2. The pretreatment system for ferric phosphate wastewater membrane concentration according to claim 1, characterized in that: The rear end of the regulating tank is connected to a pipeline mixer, and the pipeline mixer is a static spiral mixer.

3. The pretreatment system for ferric phosphate wastewater membrane concentration according to claim 2, characterized in that: The water outlet of the pipeline mixer is connected to the neutralization reaction tank. A partition is provided between the neutralization reaction tank and the flocculation reaction tank, and a through hole is provided at the bottom end of the partition. The top of the flocculation reaction tank is connected to the top of the sedimentation tank.

4. The pretreatment system for ferric phosphate wastewater membrane concentration according to claim 3, characterized in that: The overflow port at the upper end of the sedimentation tank is communicated with the middle water tank.

5. The pretreatment system for ferric phosphate wastewater membrane concentration according to claim 4, characterized in that: The middle water pool is connected to the top of the multi-media filter, and the multi-media filter is provided with cobblestone, quartz sand and activated carbon in sequence from top to bottom.

6. The pretreatment system for ferric phosphate wastewater membrane concentration according to claim 5, characterized in that: The end of the multimedia filter is communicated with the self-cleaning filter.

7. The pretreatment system for ferric phosphate wastewater membrane concentration according to claim 6, characterized in that: The sludge concentration tank is connected to the bottom of the sedimentation tank, and a sludge scraper is provided in the sludge concentration tank.

8. The pretreatment system for ferric phosphate wastewater membrane concentration according to claim 7, characterized in that: The scraper transports the sludge to the plate and frame filter press through a discharge port.

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