CN115583740A - Method and system for removing manganese from iron phosphate wastewater - Google Patents

Abstract

The invention relates to the field of wastewater treatment, and provides a method and system for removing manganese from iron phosphate wastewater, comprising the following steps: pH adjustment, adding alkaline materials into the wastewater to adjust the pH of the wastewater to 7.0-7.5; oxidation, after the pH adjustment is completed In the waste water, oxidant is put in to obtain the first waste water containing suspended solids; the preliminary filtration is to filter the suspended solids in the first waste water to obtain the first filtrate; the second filtration is to carry out the manganese ion in the first filtrate capture to obtain the second filtrate. In this way, by first adjusting the pH of the wastewater to neutral or weakly alkaline, then adding an oxidant to fully settle the manganese ions, and then remove the suspended solids through the primary filtration, and capture the remaining manganese ions through the secondary filtration, which can greatly reduce the waste water. The dosage of alkaline materials and oxidants reduces the cost of chemicals, reduces the operating burden and maintenance costs of back-end equipment, and removes manganese ions in wastewater economically and efficiently.

Description

Method and system for removing manganese from iron phosphate wastewater

technical field

The invention relates to the technical field of wastewater treatment, in particular to a method and system for removing manganese from iron phosphate wastewater.

Background technique

Iron phosphate is currently the ideal battery cathode material - the precursor of lithium iron phosphate. With the rapid development of the new energy market, the demand for power batteries, energy storage materials or equipment is increasing, so the demand for iron phosphate is also growing rapidly.

Ferric phosphate will go through synthesis, washing and other processes in the production process. The synthetic mother liquor and washing wastewater produced by it will contain a certain concentration of manganese ions. Usually, after these two streams of water are deweighted, they will be transferred to membrane concentration and weight reduction treatment. Then enter the evaporator. At present, the removal methods of manganese ions in iron phosphate production wastewater mainly include:

(1) Add alkaline materials directly, adjust the pH (hydrogen ion concentration index) to about 11, divalent manganese ions will form solid precipitation under alkaline conditions. However, with this method, the amount of material input is large, and different defects will occur according to the difference of alkaline materials. For example, if slightly soluble alkali such as calcium hydroxide is used, a large amount of waste residue will be generated, which is difficult to deal with in the later stage; liquid alkali such as ammonia water will be used. As a result, the water body expands, and the energy consumption and cost of the back-end wastewater treatment increase; the use of easily soluble alkalis such as sodium hydroxide will cost a lot of chemicals.

(2) Adding different strong oxidants, divalent manganese ions are oxidized to form manganese dioxide precipitates. However, in this method, the amount of oxidant is large, the cost is high, and it is not friendly to the back-end membrane treatment process.

(3) Adsorption by manganese sand. The equipment occupies a large area, and when the manganese ion content in the wastewater is high, the burden on the equipment is large, and the operation and maintenance costs are high, and only wastewater with a specific manganese ion content range can be removed.

How to economically and efficiently remove manganese ions in manganese-containing wastewater is an important issue to be solved urgently in the industry.

Contents of the invention

The invention provides a method and system for removing manganese from ferric phosphate wastewater, which are used to solve the defects in the prior art, such as large amount of manganese removal materials in wastewater, difficult disposal of waste residue, high equipment operation and maintenance costs, and high cost of chemicals, so as to achieve economical and efficient removal of manganese. The purpose of manganese ions in manganese wastewater.

The invention provides a method for removing manganese from iron phosphate wastewater, comprising the following steps:

pH adjustment, put alkaline materials in the wastewater to adjust the pH of the wastewater to 7.0-7.5;

Oxidation, adding an oxidant to the wastewater after the pH adjustment is completed, to obtain the first wastewater containing suspended solids;

Preliminary filtration, filtering the suspended solids in the first wastewater to obtain the first filtrate;

Secondary filtration, trapping the manganese ions in the first filtrate to obtain the second filtrate.

According to a method for removing manganese from iron phosphate wastewater provided by the present invention, before the preliminary filtration, it also includes: adding a flocculant to the first wastewater, and stirring; leaving the stirred wastewater to settle the suspended matter; The flocculant is an organic polymer flocculant.

According to a method for removing manganese from iron phosphate wastewater provided by the present invention, the stirring time after adding the flocculant is 15-20 minutes; the standing time after stirring is 0.5-1 hour.

According to a method for removing manganese from iron phosphate wastewater provided by the present invention, after the pH adjustment is completed, it also includes: detecting the content of manganese ions in the wastewater, the molar ratio of the input amount of oxidant (calculated as O) to the measured manganese ion content The range should be (1.05-1.15):1.

According to a method for removing manganese from iron phosphate wastewater provided by the present invention, after the preliminary filtration, it also includes: detecting the content of manganese ions in the first filtrate, and adding water-soluble phosphate according to the content of manganese ions, the manganese ions and The molar ratio of phosphate ions should be in the range of 1.5: (1.2-1.5).

According to a method for removing manganese from iron phosphate wastewater provided by the present invention, after the secondary filtration, it also includes: membrane concentration, and membrane concentration of the second filtrate to remove calcium and magnesium ions that are easy to scale in wastewater, and reduce waste water. amount; after the membrane is concentrated, it also includes: evaporation, evaporating and crystallizing the wastewater after the membrane is concentrated and reduced, and removing inorganic salts.

A method for removing manganese from iron phosphate wastewater according to the present invention further includes: adding a reducing agent to the first filtrate or the second filtrate to remove remaining oxidants.

The present invention also provides a system for removing manganese from iron phosphate wastewater, which is used to implement the method for removing manganese from iron phosphate wastewater described in any one of the above, including:

The pretreatment module is used to adjust the pH of the wastewater, and oxidize the pH-adjusted wastewater to obtain the first wastewater containing suspended solids, and flocculate to settle the suspended solids to obtain wastewater containing solid precipitates;

The first filtration module is used to filter the solid sediment in the waste water to obtain the first filtrate;

The second filter module is used to capture the manganese ions remaining in the first filtrate to obtain the second filtrate;

The reverse osmosis device is used to concentrate and reduce the second filtrate to obtain the second waste water;

The evaporating device evaporates the second waste water and crystallizes and separates the inorganic salts.

According to the iron phosphate wastewater manganese removal system provided by the present invention, it also includes a phosphorus replenishing device arranged between the first filter module and the second filter module.

According to the manganese removal system for iron phosphate wastewater provided by the present invention, it also includes a reduction module for removing residual oxides in wastewater, and the reduction module is arranged between the first filter module and the second filter module, or the first Between the second filter module and the reverse osmosis device.

The method for removing manganese from iron phosphate wastewater provided by the present invention comprises the following steps: adjusting pH, adding alkaline materials to the wastewater to adjust the pH of the wastewater to 7.0-7.5; oxidizing, adding an oxidant to the wastewater after pH adjustment to obtain The first wastewater of suspended solids; the primary filtration is to filter the suspended solids in the first wastewater to obtain the first filtrate; the second filtration is to capture the manganese ions in the first filtrate to obtain the second filtrate. By first adjusting the pH of the wastewater to neutral or weakly alkaline, manganese ions and phosphate ions are fully reacted and precipitated, first settled, and then an oxidant is added to oxidize manganese ions to manganese dioxide, settled again, and then removed by initial filtration Suspended solids, the second filtration captures the remaining manganese ions, which can greatly reduce the amount of alkaline materials and oxidants, reduce the cost of chemicals, reduce the operating burden and maintenance costs of back-end equipment, and remove manganese in wastewater economically and efficiently. manganese ions.

Description of drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are the For some embodiments of the present invention, those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative efforts.

Fig. 1 is the schematic flow sheet of iron phosphate wastewater manganese removal method provided by the present invention;

Fig. 2 is a schematic diagram of the iron phosphate wastewater manganese removal system provided by the present invention.

Reference signs:

1. Pretreatment module; 2. First filter module; 3. Second filter module; 4. Reverse osmosis device; 5. Evaporation device; 6. Phosphorus replenishment device; 7. Reduction module.

detailed description

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention , but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

In order to facilitate the understanding of the iron phosphate wastewater manganese removal method provided by the present invention, first explain its application scenario, in the wastewater produced by iron phosphate production, it will contain higher concentrations of manganese ions (manganese ions referred to in the present invention refer to Both are divalent manganese ions, that is, Mn ²⁺ ), and weight removal is an important part of wastewater treatment. At present, manganese ion removal methods generally include directly adding alkaline materials, adding strong oxidants, manganese sand adsorption and other methods, but There are problems such as large amount of material input, difficult disposal of waste residue, high cost of equipment operation and maintenance, and high cost of chemicals. Therefore, the present invention provides a method for removing manganese from iron phosphate wastewater to economically and efficiently remove manganese ions in wastewater.

Describe below in conjunction with Fig. 1 the iron phosphate wastewater manganese removal method of the present invention.

Referring to Fig. 1, Fig. 1 is a schematic flow chart of a method for removing manganese from iron phosphate wastewater. The manganese removal method of iron phosphate wastewater mainly includes the following steps:

S1, pH adjustment, adding alkaline materials to the wastewater, adjusting the pH of the wastewater to 7.0-7.5, and aging for 0.5-1 hour.

In the initial stage, the content of manganese ions and phosphate ions in iron phosphate wastewater is relatively high. Under acidic conditions, phosphate ions and manganese ions are difficult to fully react. By adding a relatively small amount of alkaline materials, the pH in wastewater can be adjusted to Neutral or weakly alkaline, at this time the phosphate ions and manganese ions fully react to form manganese phosphate precipitates, which can remove part of the manganese ions and phosphate ions.

At the same time, under neutral or alkaline conditions, manganese ions will be oxidized by water-soluble oxygen to precipitate manganese dioxide or manganese partial hydroxide, and then part of the manganese ions will be removed. In order to improve the removal efficiency of manganese ions, it is also possible to increase the content of dissolved oxygen in wastewater by increasing stirring or aeration, so that manganese ions can fully react and settle.

In addition, other metal ions in wastewater, such as iron ions or ferrous ions, will form precipitation under neutral or slightly alkaline conditions, so that iron ions in wastewater can be removed while manganese is removed.

Alkaline materials include but are not limited to soda ash, ammonium bicarbonate, sodium hydroxide, ammonia water, etc. In this embodiment, ammonia water is used as the alkaline material, which will not introduce new impurity ions while adjusting the pH of the wastewater. At the same time, the amount of slag is small , adding and post-processing is relatively convenient.

After step S1, about 20%-30% of manganese ions in the wastewater can be removed.

S2. Oxidation, adding an oxidizing agent to the wastewater treated in step S1 to oxidize manganese ions into manganese dioxide precipitates to obtain the first wastewater containing suspended solids.

After the wastewater is treated in step S1, detect the content of manganese ions in the wastewater, and add an oxidant to the wastewater in an appropriate proportion. The molar ratio range of the input amount of the oxidant (calculated as O) to the content of manganese ions is (1.05-1.15): 1 . The calculation with O described in this embodiment is a metering method of the amount of oxidant, that is, the oxygen atom in the 0 valence state is used as the target, and each mole of oxygen in the valence state of 0 becomes oxygen in the valence state of -2, and the electrons in the valence state The transfer is 2 moles. When various oxidants are used, it is finally converted to the molar amount of oxygen atoms, that is, the amount of electron transfer per mole of oxidant is divided by 2.

By using an excessive amount of oxidant, the manganese ions in the wastewater can be fully oxidized to generate manganese dioxide precipitates, thereby further removing the manganese ions in the wastewater. Since the content of manganese ions in the wastewater has decreased after the treatment in step S1, only a relatively small amount of oxidant can be used to fully remove the manganese ions in the wastewater, reducing the amount of oxidant used.

Ozone, sodium hypochlorite, hydrogen peroxide, etc. can be used as the oxidizing agent, as long as the oxidizing agent used can reduce manganese ions and oxidize to tetravalent manganese under neutral or slightly alkaline conditions. In this embodiment, hydrogen peroxide is used as the oxidizing agent, and no new impurity ions are introduced while manganese ions are oxidized. At the same time, it is relatively convenient to add liquid hydrogen peroxide.

S3. Preliminary filtration, filtering the solid precipitate generated in step S1 and step S2 to obtain a first filtrate.

After step S2 is completed, add flocculant to the first wastewater, stir for 15-20 minutes, fully mix the flocculant with the first wastewater, and then let it stand for 0.5-1 hour, the suspended solids in the wastewater will react with the flocculant Collect and fully settle down, and use a filter device to conduct preliminary filtration of the solid precipitate.

The filter device may adopt a vacuum filter, a filter press, etc. in the prior art, and in this embodiment, a filter press is used as the filter device. In order to improve the filtration effect, multi-stage filtration can also be adopted, and the obtained filter residue is recovered as solid waste, and the filtered wastewater is the first filtrate, which enters the clear liquid tank for temporary storage.

The flocculant can be an inorganic polymer flocculant, such as polyaluminum chloride, polyaluminum iron silicate, etc.; an organic polymer flocculant, such as polyacrylamide, polydimethyldipropylene ammonium chloride, etc., can also be used. In the embodiment, an organic polymer flocculant is used to avoid introducing new impurity ions.

S4. Secondary filtration, using a filter device to capture manganese ions in the first filtrate to obtain a second filtrate, so that the manganese ions in the waste water can reach the standard for discharge.

The first filtrate is filtered twice with a manganese sand filter. Under the catalysis of manganese sand, the manganese ions in the dissolved state can be oxidized into manganese dioxide, and the manganese ions in the wastewater are further removed, and the obtained second filtrate enters the lower a process.

In the first filtrate, the content of manganese ions is already relatively low. At this time, the manganese sand filter is used to treat the first filtrate, which can reduce the content of manganese ions in the wastewater to below 1 ppm. At the same time, compared with the direct treatment of wastewater containing high manganese ions, it reduces the equipment burden and operation and maintenance costs.

Before the first filtrate enters the manganese sand filter, the ratio of manganese ion and phosphate ion in the first filtrate can be sampled and detected. If the phosphate ion content is far lower than the manganese ion content, generally when the phosphate ion is less than 200ppm, it can be sent to the manganese sand filter. An appropriate amount of soluble phosphate is added to the wastewater to increase the concentration of phosphate ions in the first filtrate, so that the phosphate ions and manganese ions react again to form precipitates, and further reduce the content of manganese ions in the wastewater entering the manganese sand filter. Specifically, the molar ratio range of manganese ions to phosphate ions should be 1.5: (1.2-1.5)

Multiple manganese sand filters can be set in parallel to perform graded filtration on the first filtrate to improve the removal effect of manganese ions.

In another embodiment, the manganese sand filter can also be replaced by an ion exchanger to achieve the same treatment effect.

S5, membrane concentration.

The second filtrate treated in step S4 enters the reverse osmosis system for concentration to obtain the second waste water. After the concentration of the reverse osmosis membrane, the calcium and magnesium ions that are easy to scale in the waste water can be removed, and the amount of waste water can also be reduced, which is convenient for the follow-up section. conduct.

Due to the excessive oxidant added in step S2, there will be oxidant residues in the wastewater when step S5 is reached. If there is too much residual oxidant, it will cause membrane blockage and pollution. Therefore, a reducing agent needs to be added before the wastewater is concentrated by the membrane.

Reductant both can be added in the first filtrate, also can be added in the second filtrate, specifically need to consider whether oxidizing agent can affect the operation of filtering equipment in step S4, for example, when step S4 adopts manganese sand filter, reducing Agent can be added in the first filtrate, also can be added in the second filtrate; When what step S4 adopts ion exchanger, ion exchange resin can be oxidized by oxidizing agent and deteriorate, therefore, reducing agent needs to be added in the first filtrate middle. The reducing agent can be sodium sulfite, sodium bisulfite and other commonly used reducing agents in the prior art. Because the amount of reducing agent is small, the introduction of impurity ions can be temporarily ignored.

S6, evaporation.

Evaporate and crystallize the second waste water to separate the salt, so that the waste water can meet the discharge standard.

The iron phosphate wastewater manganese removal system provided by the present invention is described below, and the iron phosphate wastewater manganese removal system described below and the iron phosphate wastewater manganese removal method described above can be referred to each other.

The present invention also provides a system for removing manganese from iron phosphate wastewater, which is used to implement the above-mentioned method for removing manganese from iron phosphate wastewater. Referring to FIG. 2 , FIG. 2 is a schematic diagram of the system for removing manganese from iron phosphate wastewater provided by the present invention.

The iron phosphate wastewater manganese removal system includes a pretreatment module 1, a first filter module 2, a second filter module 3, a reverse osmosis device 4 and an evaporation device 5; wherein, the pretreatment module 1 is mainly used to adjust the pH of the wastewater, and to treat the wastewater Oxidation to obtain the first wastewater containing suspended solids, flocculation to fully settle the suspended solids to obtain wastewater containing solid sediments; the first filtration module 2 is mainly used to filter the solid sediments in the wastewater, and the obtained filter residue As solid waste treatment, the obtained first filtrate enters the second filter module 3; the second filter module 3 is used to capture the manganese ions remaining in the first filtrate, and further purifies the waste water to obtain the second filtrate; the reverse osmosis device 4 It is mainly used to remove the calcium and magnesium ions that are easy to scale in the second filtrate, and reduce the amount of waste water to obtain the concentrated second waste water; the evaporation device 5 is used to evaporate the second waste water and separate the crystallization of inorganic salts, so that the waste water can reach emission standards.

The pretreatment module 1 needs to include at least a pH regulator, an oxidation device and a flocculation device; wherein the pH regulator is equipped with alkaline materials for adjusting the pH of the wastewater, and the alkaline materials include but are not limited to various solid alkalis and Liquid bases such as soda ash, ammonium bicarbonate, sodium hydroxide, ammonia, etc. The oxidation device is equipped with an oxidizing agent, and after the pH adjustment is completed, the oxidizing agent is put into the wastewater to oxidize manganese ions in the wastewater to obtain the first wastewater containing suspended solids. Flocculants are installed in the flocculation device, including but not limited to various organic polymer flocculants and inorganic polymer flocculants. The types of flocculants can be selected according to actual needs, and it is best not to introduce new impurity ions. A stirring component can also be added in the flocculation device. After the flocculant is put into the first wastewater, the wastewater is stirred by the stirring component, so that the flocculant can fully contact with the suspended solids and promote the settlement of the suspended solids.

In another embodiment, a stirring component can also be installed in the pH regulator and the oxidation device to promote the process of pH adjustment and oxidation.

The first filter module 2 is connected to the outlet of the pretreatment module 1, and is mainly used to filter the solid sediment in the waste water. Specifically, the first filter module 2 mainly includes a first filter, and the first filter can be vacuum filtered. machine, filter press, etc., in this embodiment, the first filter is a filter press. In order to improve the filtering effect, the first filtering module 2 can adopt a plurality of first filters connected in series, for example, the outlet of the upstream filter press is connected to the inlet of the downstream filter press to perform multi-stage filtration of wastewater to improve the filtering effect. After the first filtration module 2 filters the solid sediment in the waste water, the first filtrate is obtained.

The inlet of the second filter module 3 is connected to the outlet of the first filter module 2 , and the first filtrate filtered by the first filter module 2 enters the second filter module 3 for further processing. The second processing module includes a second filter, and the second filter is mainly used to trap residual manganese ions in the first filtrate. The specific second filter can be a manganese sand filter, an ion exchanger, etc. In this embodiment , the second filter adopts manganese sand filter, under the catalysis of manganese sand, manganese ions are oxidized into manganese dioxide.

In order to improve the filtering effect, a plurality of second filters can be connected in series to form a filter group, that is, the outlet of the upstream manganese sand filter is connected to the inlet of the downstream manganese sand filter to perform multi-stage filtration of wastewater. In order to ensure the smooth progress of the filtering work, multiple filtering groups can also be connected in parallel, one for standby and one for use. When one of the filtering groups fails, the standby filtering group can be activated to ensure the smooth progress of the filtering work. The first filtrate is filtered through the second filter module 3 to obtain the second filtrate.

Also be provided with phosphorus replenishing device 6 between the first filter module 2 and the second filter module 3, soluble phosphate is housed in the phosphorus replenishing device 6, when detecting that the concentration of phosphate ion in the first filtrate is far lower than manganese ion concentration When starting the phosphorus replenishing device 6 to replenish phosphate radicals in the first filtrate, the phosphate radical ions react with manganese ions to generate manganese phosphate precipitation, which reduces the manganese ion content in the first filtrate when entering the second filter module 3 to the greatest extent, and reduces the second The burden and operation and maintenance cost of the filter module 3.

The inlet of the reverse osmosis device 4 is connected with the outlet of the second filtration module 3, and is mainly used to concentrate the second filtrate, and remove the calcium and magnesium ions that are easy to scale in the second filtrate, and generate the second wastewater to ensure the smoothness of the subsequent process. went well.

In order to reduce the impact of the oxidizing agent on the reverse osmosis membrane, a reduction module 7 is also arranged upstream of the reverse osmosis device 4, and a reducing agent is housed in the reduction module 7, which is used to reduce the remaining oxidizing agent in the waste water and reduce the residual oxidizing agent caused by excessive oxidant residue. Causes clogging and fouling of reverse osmosis membrane. The reducing agent can adopt the reducing agent commonly used in prior art such as sodium sulfite, sodium bisulfite.

In one embodiment, the reduction module 7 is arranged between the second filter module 3 and the first filter module 2 , and the oxidant is removed before the first filtrate enters the second filter module 3 .

In another embodiment, the reduction module 7 is arranged between the second filtration module 3 and the reverse osmosis device 4 , and it is only necessary to ensure that the reducing agent is removed before the second filtrate enters the reverse osmosis device 4 .

Specifically, the position of the reduction module 7 is selected according to the type of the second filter. When the second filter adopts a manganese sand filter, the reduction module 7 can be arranged upstream or downstream of the second filter module 3. When the second filter The ion exchanger is used in the filter, and the reduction module 7 is arranged upstream of the second filter module 3 to prevent the oxidant from oxidizing the ion exchange resin and affecting the normal operation of the ion exchanger. In this embodiment, the reduction module 7 is arranged between the first filter module 2 and the second filter module 3 .

The inlet of the evaporating device 5 is connected to the outlet of the reverse osmosis device 4, and the evaporating device 5 can adopt an existing multi-effect evaporator, Mvr evaporator, etc., to evaporate the second waste water after the membrane concentration, and to separate the inorganic salt crystallization, The evaporated waste water reaches the discharge standard.

The innovation of the present invention is that in the prior art, when removing manganese ions in wastewater, the wing plates adopt methods such as directly adding alkaline materials, adding strong oxidants, manganese sand adsorption, etc., but there is a large amount of materials put in, and the waste residue is difficult to handle. The cost of equipment operation and maintenance and the high cost of pharmaceuticals.

In the present invention, in the initial stage, the content of manganese ions and phosphate ions in the waste water is relatively high, by adding a relatively small amount of alkaline materials to the waste water, the pH of the waste water is adjusted to neutral or slightly alkaline, so that the manganese ions and The phosphate ion fully reacts and precipitates to achieve the purpose of primary precipitation.

After the primary settling is completed, add an oxidant to the wastewater to oxidize the divalent manganese ions into manganese dioxide precipitates. After the primary settling, the content of manganese ions in the wastewater has decreased, so adding a relatively small amount of oxidant can achieve two For the purpose of secondary sedimentation, reduce the amount of oxidizing agent. After the secondary sedimentation, the suspended solids are filtered out through preliminary filtration, and then filtered again to capture the residual manganese ions in the wastewater, thereby reducing the content of manganese ions in the wastewater to below 1ppm.

By adopting the above process, the amount of alkaline materials and oxidants can be greatly reduced, and the cost of chemicals can be reduced. In addition, through two sedimentation, the content of manganese ions in the wastewater entering the back-end equipment can be greatly reduced, reducing the operating burden of the back-end equipment And operation and maintenance costs, economical and efficient removal of manganese ions in wastewater.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. a method for removing manganese from iron phosphate wastewater, is characterized in that, comprises the following steps: pH adjustment, put alkaline materials in the wastewater to adjust the pH of the wastewater to 7.0-7.5; Oxidation, adding an oxidant to the wastewater after pH adjustment to obtain the first wastewater containing suspended solids; Preliminary filtration, filtering the suspended solids in the first wastewater to obtain the first filtrate; Secondary filtration, trapping the manganese ions in the first filtrate to obtain the second filtrate. 2. iron phosphate waste water manganese removal method according to claim 1, is characterized in that, before described primary filtration, also comprises: Add flocculant to the first waste water, and stir; The stirred wastewater is allowed to stand still to allow the suspended matter to settle; the flocculant is an organic macromolecular flocculant. 3. The method for removing manganese from iron phosphate wastewater according to claim 2, characterized in that the stirring time after adding the flocculant is 15-20 minutes, and the standing time after stirring is 0.5-1 hour. 4. method for removing manganese from ferric phosphate wastewater according to claim 1, is characterized in that, after described pH adjustment is completed, also comprises: To detect the content of manganese ions in wastewater, the molar ratio range of the input amount of oxidant (calculated as O) to the measured manganese ion content should be (1.05-1.15):1. 5. iron phosphate waste water manganese removal method according to claim 1, is characterized in that, after described primary filtration, also comprises: Detect the manganese ion content in the first filtrate, and put in water-soluble phosphate according to the manganese ion content, and the molar ratio scope of the manganese ion and the phosphate ion should be 1.5:(1.2-1.5). 6. according to any one of claim 1-5 described iron phosphate wastewater manganese removal method, it is characterized in that, after described secondary filtration, also comprise: Membrane concentration: Concentrate the second filtrate membrane to remove calcium and magnesium ions that are easy to scale in the wastewater, and reduce the amount of wastewater; after the membrane concentration, it also includes: evaporation, evaporative crystallization of the wastewater after the membrane concentration and reduction , to remove inorganic salts. 7. The method for removing manganese from iron phosphate wastewater according to claim 1, further comprising: adding a reducing agent to the first filtrate or the second filtrate to remove remaining oxidants. 8. A ferric phosphate wastewater manganese removal system is used for implementing the ferric phosphate wastewater manganese removal method as claimed in any one of claims 1-7, characterized in that it comprises: The pretreatment module (1) is used to adjust the pH of the wastewater, and oxidize the pH-adjusted wastewater to obtain the first wastewater containing suspended solids, and flocculate the suspended solids in the first wastewater to settle to obtain a precipitate containing solids waste water; The first filtration module (2), is used for filtering the solid sediment in the waste water, obtains the first filtrate; The second filter module (3) is used to capture the manganese ions remaining in the first filtrate to obtain the second filtrate; The reverse osmosis device (4) concentrates and reduces the weight of the second filtrate to obtain the second waste water; The evaporating device (5) evaporates the second waste water, and crystallizes and separates the inorganic salts. 9. The iron phosphate wastewater manganese removal system according to claim 8, further comprising a phosphorus replenishing device (6) arranged between the first filter module (2) and the second filter module (3) . 10. The iron phosphate wastewater manganese removal system according to claim 8, characterized in that, it also includes a reduction module (7) for removing residual oxides in the wastewater, and the reduction module (7) is arranged on the first Between the filter module (2) and the second filter module (3), or between the second filter module (3) and the reverse osmosis device (4).

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