Treatment system for iron phosphate production wastewater

Abstract

The utility model discloses a treatment system for iron phosphate production wastewater, which comprises a recycled phosphoric acid purification and recovery section for treating washing water to obtain recycled phosphoric acid and first clear liquid; the recycled produced water preparation section is used for treating the first clear liquid to obtain impurity concentrated liquid and recycled produced water; the deep purification and discharge section is used for purifying the impurity concentrated liquor and the reaction mother liquor to obtain produced water reaching the standard; wherein the reuse produced water preparation working section comprises a pH adjusting unit, a first clear liquid, a second clear liquid and a water recycling unit, and the pH adjusting unit is used for adjusting the pH of the first clear liquid and then outputting raw water; the impurity concentration unit is used for carrying out concentration treatment on a first mixture containing raw water and supplemented water and then outputting impurity concentrated liquor and recycled produced water; and the water replenishing unit is used for inputting replenished water into the impurity concentration unit.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, and specifically relates to a treatment system for wastewater produced in the production of iron phosphate. Background Art

[0002] Anhydrous iron phosphate (molecular formula: FePO 4 ) is an important chemical raw material and is widely used as the cathode material of lithium-ion batteries. The iron method (Fe + H 3 PO 4 →FePO 4 +H 2 ) and the iron red method (Fe 2 O 3 +2H 3 PO 4 →2FePO 4 +3H 2 O) are common methods for producing battery-grade anhydrous iron phosphate. The production processes of the iron method / iron red method mainly include the steps of: synthesis - solid-liquid separation (usually by pressure filtration) - washing - drying - pulverizing and packaging. In the above production process, reaction mother liquor is generated in the solid-liquid separation section, and washing water is generated in the washing section. The wastewater produced in the production of iron phosphate composed of washing water and reaction mother liquor contains rich recyclable resources and water pollutants, and needs to be discharged after purification and resource recovery.

[0003] In the prior art, there are mainly three treatment methods for wastewater produced in the production of iron phosphate. The first is to directly mix the washing water and the reaction mother liquor for treatment. The second is to treat the washing water and the reaction mother liquor separately. The third is to first perform pretreatment for impurity removal on the washing water and the reaction mother liquor separately, and then mix them for resource recovery treatment. Among them, the second and the third are usually carried out in parallel and adopt substantially the same process.

[0004] First, taking the production of a certain anhydrous iron phosphate as an example, the water volume of the washing water is 40m 3 / h, the TDS is 15.68g / L, the phosphoric acid concentration is 15.32g / L, the silicon element concentration is 22.3mg / L, the fluoride ion concentration is 10mg / L, while the water volume of the reaction mother liquor is only 0.5m 3 / h, TDS is 179.29g / L, phosphoric acid concentration is 159.47g / L, silicon concentration is 1113.5mg / L, and fluoride concentration is 500mg / L. By comparison, it can be seen that there are huge differences in the water volume and water quality parameter concentrations of wash water and reaction mother liquor. Among them, the wash water has a large water volume and less silicon and fluoride ion content, while the reaction mother liquor has a small water volume. Although the phosphoric acid content is high, the silicon and fluoride ion content is high. Therefore, the above three treatment methods are not conducive to the efficient recovery of resources and the deep removal of pollutants, and cannot take into account low cost, high efficiency and zero emissions. In addition, both wash water and reaction mother liquor contain a lot of phosphoric acid. The traditional method uses calcium hydroxide for neutralization and precipitation, which has high alkali consumption and produces a large amount of solid waste.

[0005] Secondly, the target resource recovery of the current iron phosphate production wastewater treatment is usually to obtain ammonium sulfate and ammonium phosphate by evaporation and crystallization at the end. These resources cannot be directly reused by the enterprise itself, but are usually sold to the outside, which increases sales costs. Although Chinese utility model patent application CN114873824A and Chinese utility model patent CN219991386U disclose the technical solution of phosphoric acid as the target resource recovery, they still adopt the treatment method of directly mixing the washing water and the reaction mother liquor for treatment, and the terminal liquid after the phosphoric acid recovery still contains a lot of impurities and cannot be directly reused or discharged. Contents of utility model

[0006] The technical problem to be solved by the utility model is to provide a method and system for treating wastewater from iron phosphate production, which can not only recycle phosphoric acid for use in the iron phosphate synthesis section, but also take into account low cost, high efficiency and zero discharge.

[0007] In order to achieve the above purpose, the utility model first provides a method for treating wastewater from iron phosphate production. The technical scheme is as follows:

[0008] The treatment method of ferric phosphate production wastewater, which includes wash water and reaction mother liquor generated in the process of producing ferric phosphate by iron method / iron red method, includes the following steps:

[0009] (1) The process of purifying and recovering recycled phosphoric acid includes:

[0010] Pre-treating the washing water in sequence, wherein the pre-treatment includes filtering treatment, cooling treatment, resin adsorption treatment and ultrafiltration treatment to obtain ultrafiltration clear liquid;

[0011] The ultrafiltration clear liquid is subjected to phosphoric acid recovery treatment, that is, recycled phosphoric acid and the first clear liquid are obtained;

[0012] (2) Recycling water preparation process, including:

[0013] The pH of the first clear liquid is adjusted with alkaline solution to obtain raw water;

[0014] The first mixture including raw water and make-up water is concentrated to obtain concentrated impurity liquid and recycled product water.

[0015] (3) Advanced purification and discharge process, including:

[0016] The second mixture including concentrated impurity liquid, reaction mother liquor and resin regeneration liquid is purified to obtain qualified product water.

[0017] As a further improvement to the above treatment method of iron phosphate production wastewater:

[0018] The TDS of the washing water ≤ 16500 mg / L, phosphoric acid concentration ≤ 16200 mg / L, sulfate concentration ≤ 150 mg / L, sodium ion concentration ≤ 15 mg / L, total iron ion concentration ≤ 30 mg / L, manganese ion concentration ≤ 30 mg / L, calcium ion concentration ≤ 3 mg / L, magnesium ion concentration ≤ 0.5 mg / L, copper ion concentration ≤ 1 mg / L, zinc ion concentration ≤ 0.5 mg / L, silicon element concentration ≤ 28 mg / L, fluoride ion concentration ≤ 14 mg / L;

[0019] The TDS of the ultrafiltration filtrate ≤ 16500 g / L, phosphoric acid concentration ≤ 16200 mg / L, sulfate concentration ≤ 150 mg / L, sodium ion concentration ≤ 15 mg / L, total iron ion concentration ≤ 0.5 mg / L, manganese ion concentration ≤ 0.5 mg / L, calcium ion concentration ≤ 0.5 mg / L, magnesium ion concentration ≤ 0.5 mg / L, copper ion concentration ≤ 0.5 mg / L, zinc ion concentration ≤ 0.5 mg / L, silicon element concentration ≤ 28 mg / L, fluoride ion concentration ≤ 14 mg / L;

[0020] The TDS of the recycled phosphoric acid ≤ 95000 mg / L, phosphoric acid concentration ≤ 94000 mg / L, sulfate concentration ≤ 610 mg / L, sodium ion concentration ≤ 60 mg / L, total iron ion concentration ≤ 3 mg / L, manganese ion concentration ≤ 3 mg / L, calcium ion concentration ≤ 3 mg / L, magnesium ion concentration ≤ 3 mg / L, copper ion concentration ≤ 3 mg / L, zinc ion concentration ≤ 2.5 mg / L, silicon element concentration ≤ 140 mg / L, fluoride ion concentration ≤ 20 mg / L.

[0021] As a further improvement to the above treatment method of iron phosphate production wastewater: The process of phosphoric acid recovery treatment for the ultrafiltration filtrate is:

[0022] The ultrafiltration filtrate is concentrated by reverse osmosis membrane to obtain phosphoric acid concentrated liquid with a mass fraction of 8 - 10% and a purity ≥ 96% and the first product water.

[0023] The concentrated phosphoric acid solution is treated by reverse osmosis membrane concentration to obtain recycled phosphoric acid with a mass fraction of 20-85% and secondary produced water; wherein, the primary produced water and the secondary produced water constitute the first clear liquid.

[0024] As a further improvement of the above method for treating phosphoric acid iron production wastewater:

[0025] Strong acid cation resin is used for resin adsorption treatment;

[0026] The resin used for resin adsorption treatment is regenerated with dilute sulfuric acid with a mass fraction of 8-10%, and the resin regeneration liquid with a sulfuric acid mass fraction of 6-7% obtained enters the second mixture;

[0027] The regenerated resin is rinsed with pure water, and the obtained rinsing water is refluxed to be mixed with the washing water and then subjected to filtration treatment.

[0028] As a further improvement of the above method for treating phosphoric acid iron production wastewater:

[0029] The makeup water is obtained by sequentially performing sand filtration treatment and activated carbon adsorption on tap water. The TDS of the makeup water ≤ 250 mg / L, the sulfate ion concentration ≤ 160 mg / L, the sodium ion concentration ≤ 12 mg / L, the calcium ion concentration ≤ 50 mg / L, the magnesium ion concentration ≤ 9 mg / L, and the silicon element concentration ≤ 9 mg / L;

[0030] The TDS of the raw water ≤ 1100 mg / L, the phosphoric acid concentration ≤ 860 mg / L, the sulfate ion concentration ≤ 7 mg / L, the sodium ion concentration ≤ 210 mg / L, the total iron ion concentration ≤ 0.05 mg / L, the manganese ion concentration ≤ 0.05 mg / L, the calcium ion concentration ≤ 0.05 mg / L, the magnesium ion concentration ≤ 0.05 mg / L, the copper ion concentration ≤ 0.05 mg / L, the zinc ion concentration ≤ 0.04 mg / L, the silicon element concentration ≤ 2.5 mg / L, and the fluoride ion concentration ≤ 13 mg / L; the pH of the raw water is 6-7;

[0031] The TDS of the impurity concentrated liquid ≤ 14200 mg / L, the phosphoric acid concentration ≤ 9400 mg / L, the sulfate ion concentration ≤ 1500 mg / L, the sodium ion concentration ≤ 2400 mg / L, the total iron ion concentration ≤ 0.5 mg / L, the manganese ion concentration ≤ 0.5 mg / L, the calcium ion concentration ≤ 400 mg / L, the magnesium ion concentration ≤ 75 mg / L, the copper ion concentration ≤ 0.5 mg / L, the zinc ion concentration ≤ 0.4 mg / L, the silicon element concentration ≤ 90 mg / L, and the fluoride ion concentration ≤ 110 mg / L.

[0032] As a further improvement to the above method for treating phosphoric iron production wastewater: It also includes using a part of the concentrated impurity solution to backwash the sand filter tank used for sand filtration treatment and the activated carbon tank used for activated carbon adsorption. The obtained backwash water is mixed with the concentrated impurity solution, the reaction mother liquor, and the resin regeneration solution to form a second mixture, which then enters the deep purification and discharge process.

[0033] As a further improvement to the above method for treating phosphoric iron production wastewater: The process of concentrating the first mixture is as follows:

[0034] The first mixture is subjected to reverse osmosis membrane concentration treatment to obtain primary concentrated water and primary produced water;

[0035] The primary concentrated water is subjected to reverse osmosis membrane concentration treatment to obtain concentrated impurity solution and secondary produced water;

[0036] The primary produced water and the secondary produced water are subjected to reverse osmosis membrane concentration treatment to obtain secondary concentrated water and recycled produced water; among them, the secondary concentrated water is refluxed into the first mixture.

[0037] As a further improvement to the above method for treating phosphoric iron production wastewater:

[0038] The TDS of the resin regeneration solution ≤ 100000 mg / L, the sulfate ion concentration ≤ 95000 mg / L, the total iron ion concentration ≤ 2450 mg / L, the manganese ion concentration ≤ 2200 mg / L, the calcium ion concentration ≤ 165 mg / L, the magnesium ion concentration ≤ 30 mg / L, the copper ion concentration ≤ 80 mg / L, the zinc ion concentration ≤ 21 mg / L;

[0039] The TDS of the reaction mother liquor ≤ 188000 mg / L, the phosphoric acid concentration ≤ 168000 mg / L, the sulfate ion concentration ≤ 15900 mg / L, the sodium ion concentration ≤ 1450 mg / L, the total iron ion concentration ≤ 30 mg / L, the manganese ion concentration ≤ 30 mg / L, the calcium ion concentration ≤ 2.8 mg / L, the magnesium ion concentration ≤ 0.5 mg / L, the copper ion concentration ≤ 1 mg / L, the zinc ion concentration ≤ 0.5 mg / L, the silicon element concentration ≤ 1150 mg / L, the fluoride ion concentration ≤ 520 mg / L;

[0040] The TDS of the second mixture ≤ 54000 mg / L, the phosphoric acid concentration ≤ 36000 mg / L, the sulfate ion concentration ≤ 14500 mg / L, the sodium ion concentration ≤ 2000 mg / L, the total iron ion concentration ≤ 330 mg / L, the manganese ion concentration ≤ 300 mg / L, the calcium ion concentration ≤ 330 mg / L, the magnesium ion concentration ≤ 60 mg / L, the copper ion concentration ≤ 12 mg / L, the zinc ion concentration ≤ 4 mg / L, the silicon element concentration ≤ 220 mg / L, the fluoride ion concentration ≤ 150 mg / L.

[0041] As a further improvement of the above-mentioned treatment method for phosphoric iron production wastewater: The deep purification and discharge process specifically includes:

[0042] Add a precipitant to the second mixture, then perform flocculation sedimentation and solid-liquid separation treatment to obtain a second clear liquid;

[0043] Adjust the pH of the second clear liquid to 4-5 with an acid solution to obtain a third clear liquid.

[0044] As a further improvement of the above-mentioned treatment method for phosphoric iron production wastewater: The deep purification and discharge process further includes:

[0045] Perform Fenton oxidation treatment on the third clear liquid, then perform flocculation sedimentation and solid-liquid separation treatment to obtain a fourth clear liquid;

[0046] Adjust the pH of the fourth clear liquid to 6-9 with an alkaline solution to obtain qualified product water.

[0047] In order to achieve the above object, the present invention secondly provides three treatment systems for phosphoric iron production wastewater, and the technical solutions are as follows:

[0048] The first treatment system for phosphoric iron production wastewater includes:

[0049] A recycled phosphoric acid purification and recovery section for treating wash water to obtain recycled phosphoric acid and a first clear liquid;

[0050] A recycled product water preparation section for treating the first clear liquid to obtain a concentrated impurity liquid and recycled product water;

[0051] A deep purification and discharge section for purifying the concentrated impurity liquid and reaction mother liquor to obtain qualified product water;

[0052] Among them, the recycled phosphoric acid purification and recovery section includes:

[0053] A filtration unit that filters the wash water and outputs a filtrate;

[0054] A heat exchange unit that cools the filtrate and outputs a coolant;

[0055] A resin adsorption unit that adsorbs the coolant and outputs an adsorbed liquid;

[0056] An ultrafiltration unit that ultrafilters the adsorbed liquid and outputs an ultrafiltration clear liquid;

[0057] A phosphoric acid concentration unit that concentrates the ultrafiltration clear liquid and outputs recycled phosphoric acid and a first clear liquid.

[0058] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The filtration unit includes a precision filter and a first filter press. The precision filter filters the washing water to obtain filtrate and filter cake. The filtrate is stored in a filtrate storage tank, and the filter cake is collected by backwashing to form a slag liquid that is stored in a slag liquid storage tank. The first filter press filters the slag liquid to obtain a first filtrate that is refluxed to the washing water storage tank.

[0059] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The heat exchange unit includes a plate heat exchanger.

[0060] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The resin adsorption unit includes a resin adsorption tower, a resin regeneration mechanism, and a resin rinsing mechanism. Strong acid cation resin is provided in the resin adsorption tower. The resin regeneration mechanism sprays and regenerates the strong acid cation resin with dilute sulfuric acid to obtain the resin regeneration liquid. The resin rinsing mechanism rinses the strong acid cation resin with pure water, and the obtained rinsing liquid is refluxed to the washing water storage tank.

[0061] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The resin regeneration mechanism includes a graphite diluter that processes pure water and concentrated sulfuric acid to obtain dilute sulfuric acid for spray regeneration. The resin rinsing mechanism includes a first pipeline for inputting pure water into the graphite diluter and a second pipeline for inputting pure water into the resin adsorption tower.

[0062] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The resin adsorption unit further includes an adsorbed liquid storage tank, a concentrated sulfuric acid storage tank, a dilute sulfuric acid storage tank, a resin regeneration liquid storage tank, a rinsing liquid storage tank, and a pure water storage tank.

[0063] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The ultrafiltration unit includes an ultrafiltration device and an ultrafiltration filtrate storage tank. The ultrafiltration device uses an internal pressure type hollow PES membrane sheet.

[0064] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The ultrafiltration concentrate obtained after the ultrafiltration unit filters the adsorbed liquid is refluxed to the washing water storage tank.

[0065] As a further improvement to the above-mentioned first treatment system for phosphoric acid iron production wastewater: The phosphoric acid concentration unit includes:

[0066] A first reverse osmosis device that concentrates the ultrafiltration filtrate to obtain a phosphoric acid concentrate and a first produced water;

[0067] The second reverse osmosis device, which concentrates the concentrated phosphoric acid solution to obtain recycled phosphoric acid and the second produced water; wherein, the first produced water and the second produced water constitute the first clear liquid.

[0068] As a further improvement of the above-mentioned first treatment system for phosphoric iron production wastewater: The phosphoric acid concentration unit further includes a concentrated phosphoric acid storage tank, a recycled phosphoric acid storage tank, and a first clear liquid storage tank.

[0069] The second treatment system for phosphoric iron production wastewater includes:

[0070] The recycled phosphoric acid purification and recovery section, which is used to treat the washing water to obtain recycled phosphoric acid and the first clear liquid;

[0071] The recycled produced water preparation section, which is used to treat the first clear liquid to obtain a concentrated impurity liquid and recycled produced water;

[0072] The deep purification and discharge section, which is used to purify the concentrated impurity liquid and the reaction mother liquid to obtain up-to-standard produced water;

[0073] Among them, the recycled produced water preparation section includes:

[0074] The pH adjustment unit, which adjusts the pH of the first clear liquid and then outputs raw water;

[0075] The impurity concentration unit, which concentrates the first mixture including raw water and makeup water and then outputs a concentrated impurity liquid and recycled produced water;

[0076] The makeup water unit, which is used to input makeup water into the impurity concentration unit.

[0077] As a further improvement of the above-mentioned second treatment system for phosphoric iron production wastewater: The pH adjustment unit includes a pH adjustment tank and a first sodium hydroxide dosing device for dosing sodium hydroxide into the pH adjustment tank.

[0078] As a further improvement of the above-mentioned second treatment system for phosphoric iron production wastewater: The impurity concentration unit includes a first mixture storage tank and:

[0079] The first-stage reverse osmosis device, which concentrates the first mixture to obtain the first-stage concentrated water and the first-stage produced water;

[0080] The second-stage reverse osmosis device, which concentrates the first-stage concentrated water to obtain a concentrated impurity liquid and the second-stage produced water;

[0081] The third-stage reverse osmosis device, which concentrates the first-stage produced water and the second-stage produced water to obtain the second-stage concentrated water and recycled produced water; wherein, the second-stage concentrated water is refluxed to the first mixture storage tank.

[0082] As a further improvement to the second treatment system for phosphoric acid iron production wastewater described above: The impurity concentration unit further includes a primary concentrated water storage tank, a two-stage produced water storage tank, an impurity concentrated liquid storage tank, and a recycled produced water storage tank. The primary produced water and the secondary produced water are stored in the two-stage produced water storage tank.

[0083] As a further improvement to the second treatment system for phosphoric acid iron production wastewater described above: The make-up water unit includes a tap water storage tank, a sand filter tank, and an activated carbon tank for treating tap water.

[0084] As a further improvement to the second treatment system for phosphoric acid iron production wastewater described above: The recycled produced water preparation section further includes a backwashing unit for flushing the sand filter tank and the activated carbon tank.

[0085] As a further improvement to the second treatment system for phosphoric acid iron production wastewater described above: The backwashing unit includes a third pipeline connecting the impurity concentrated liquid storage tank and the sand filter tank, a fourth pipeline connecting the impurity concentrated liquid storage tank and the activated carbon tank, and a backwashing water storage tank for storing the backwashing water formed by flushing.

[0086] As a further improvement to the second treatment system for phosphoric acid iron production wastewater described above:

[0087] The recycled phosphoric acid purification and recovery section includes:

[0088] A filtration unit that filters the washing water and outputs filtrate;

[0089] A heat exchange unit that cools the filtrate and outputs coolant;

[0090] A resin adsorption unit that adsorbs the coolant and outputs the post-adsorption liquid;

[0091] An ultrafiltration unit that ultrafilters the post-adsorption liquid and outputs ultrafiltration clear liquid;

[0092] A phosphoric acid concentration unit that concentrates the ultrafiltration clear liquid and outputs recycled phosphoric acid and first clear liquid.

[0093] The deep purification and discharge section includes a homogenization unit that is used to mix the impurity concentrated liquid, the reaction mother liquor, the resin regeneration liquid, and the backwashing water into a second mixture.

[0094] The third treatment system for phosphoric acid iron production wastewater includes:

[0095] A recycled phosphoric acid purification and recovery section for treating washing water to obtain recycled phosphoric acid and first clear liquid;

[0096] The recycled product water preparation section is used to treat the first clear liquid to obtain an impurity concentrated solution and recycled product water;

[0097] The deep purification and discharge section is used to purify the impurity concentrated solution and the reaction mother liquor to obtain up-to-standard product water;

[0098] Among them, the recycled phosphoric acid purification and recovery section includes:

[0099] The filtration unit filters the washing water and outputs the filtrate;

[0100] The heat exchange unit cools the filtrate and outputs the coolant;

[0101] The resin adsorption unit adsorbs the coolant and outputs the post-adsorption liquid;

[0102] The ultrafiltration unit ultrafilters the post-adsorption liquid and outputs the ultrafiltration clear liquid;

[0103] The phosphoric acid concentration unit concentrates the ultrafiltration clear liquid and outputs recycled phosphoric acid and the first clear liquid;

[0104] The recycled product water preparation section includes:

[0105] The pH adjustment unit adjusts the pH of the first clear liquid and outputs raw water;

[0106] The impurity concentration unit concentrates the first mixture including raw water and make-up water and outputs an impurity concentrated solution and recycled product water;

[0107] The make-up water unit is used to input make-up water into the impurity concentration unit;

[0108] The deep purification and discharge section includes:

[0109] The homogenization unit is used to mix the impurity concentrated solution, the reaction mother liquor and the resin regeneration liquid to obtain a second mixture;

[0110] The softening unit is used to remove impurity ions from the second mixture and output the second clear liquid;

[0111] The organic matter degradation unit is used to remove organic matter from the second clear liquid and output up-to-standard product water.

[0112] As a further improvement to the above-mentioned third treatment system for iron phosphate production wastewater: The resin adsorption unit includes a resin adsorption tower, a resin regeneration mechanism, and a resin rinsing mechanism. The resin adsorption tower is provided with strongly acidic cation resin. The resin regeneration mechanism sprays and regenerates the strongly acidic cation resin with dilute sulfuric acid to obtain the resin regeneration liquid. The resin rinsing mechanism rinses the strongly acidic cation resin with pure water, and the rinsing liquid obtained is returned to the wash water storage tank.

[0113] As a further improvement to the above-mentioned third treatment system for iron phosphate production wastewater: The phosphoric acid concentration unit includes:

[0114] A first reverse osmosis device that concentrates the ultrafiltration filtrate to obtain a concentrated phosphoric acid solution and a first product water;

[0115] A second reverse osmosis device that concentrates the concentrated phosphoric acid solution to obtain recycled phosphoric acid and a second product water; wherein, the first product water and the second product water constitute the first clear liquid.

[0116] As a further improvement to the above-mentioned third treatment system for iron phosphate production wastewater: The impurity concentration unit includes a first mixture storage tank and:

[0117] A first-stage reverse osmosis device that concentrates the first mixture to obtain a first-stage concentrated water and a first-stage product water;

[0118] A second-stage reverse osmosis device that concentrates the first-stage concentrated water to obtain an impurity concentrated liquid and a second-stage product water;

[0119] A third-stage reverse osmosis device that concentrates the first-stage product water and the second-stage product water to obtain a second-stage concentrated water and a recycled product water; wherein, the second-stage concentrated water is returned to the first mixture storage tank.

[0120] As a further improvement to the above-mentioned third treatment system for iron phosphate production wastewater: The water replenishment unit includes a tap water storage tank, a sand filter tank, and an activated carbon tank for treating tap water;

[0121] The recycled product water preparation section further includes a backwashing unit for flushing the sand filter tank and the activated carbon tank; the backwashing unit includes a third pipeline connecting the impurity concentrated liquid storage tank and the sand filter tank, a fourth pipeline connecting the impurity concentrated liquid storage tank and the activated carbon tank, and a backwashing water storage tank for storing the backwashing water formed by flushing.

[0122] As a further improvement to the above-mentioned third treatment system for iron phosphate production wastewater: The homogenization unit includes a homogenization tank, and the impurity concentrated liquid, the reaction mother liquor, the resin regeneration liquid, and the backwashing water are mixed in the homogenization tank to form a second mixture.

[0123] As a further improvement to the treatment system for the third type of iron phosphate production wastewater described above: The softening unit includes a chemical reaction tank, a flocculation tank, a sludge tank, a second filter press, a precipitant dosing device for adding a precipitant to the chemical reaction tank, and a first flocculant dosing device for adding a flocculant to the flocculation tank, which are connected in sequence.

[0124] As a further improvement to the treatment system for the third type of iron phosphate production wastewater described above: The precipitant dosing device includes a second sodium hydroxide dosing device and a calcium hydroxide dosing device. The calcium hydroxide dosing device includes a bin for storing quicklime or slaked lime and a pulping tank for making calcium hydroxide slurry.

[0125] As a further improvement to the treatment system for the third type of iron phosphate production wastewater described above: The organic matter degradation unit includes a pH adjustment tank, a Fenton reaction tank, a sedimentation tank, a pH back adjustment tank, an acid solution dosing device for adding an acid solution to the pH adjustment tank, a ferrous sulfate dosing device for adding ferrous sulfate to the Fenton reaction tank, a hydrogen peroxide dosing device for adding hydrogen peroxide to the Fenton reaction tank, a second flocculant dosing device for adding a flocculant to the sedimentation tank, and a third sodium hydroxide dosing device for adding sodium hydroxide to the pH back adjustment tank, which are connected in sequence.

[0126] As a further improvement to the treatment system for the third type of iron phosphate production wastewater described above: The sedimentation tank is an inclined plate sedimentation tank, and the sludge deposited in the inclined plate sedimentation tank flows into the second filter press.

[0127] The treatment method and treatment system for iron phosphate production wastewater of the present utility model have the following advantages:

[0128] (1) The present utility model fully considers the differences in water volume and water quality parameters between washing water and reaction mother liquor. First, taking the washing water with a large water volume and fewer impurities as the object of action, the phosphoric acid and produced water in the washing water are recovered first, and then the residual liquid (i.e., impurity concentrated liquid) is mixed with the reaction mother liquor for deep purification, significantly improving the treatment efficiency and reducing the treatment cost.

[0129] (2) The target resource recovery products of the present utility model are phosphoric acid and produced water, which can be directly reused in the iron phosphate synthesis section without external sales, saving raw material costs and sales costs.

[0130] (3) The process and structure of the present utility model are simple, the equipment investment cost is low, the energy consumption is low, realizing the resource reuse and up-to-standard discharge of wastewater, taking into account low cost, high benefit and zero discharge, and having extremely strong practicability.

[0131] The following further describes the embodiments of the utility model provided in this specification in conjunction with the accompanying drawings and specific implementation manners. Some of the additional aspects and advantages of the embodiments of the utility model provided in this specification will be given in the following description, some will become apparent from the following description, or be understood through the practice of the embodiments of the utility model provided in this specification. Description of the Drawings

[0132] The accompanying drawings that form a part of the embodiments of the utility model provided in this specification are used to assist in understanding the embodiments of the utility model provided in this specification. The content provided in the accompanying drawings and the relevant descriptions in the embodiments of the utility model provided in this specification can be used to explain the embodiments of the utility model provided in this specification, but do not constitute an improper limitation on the embodiments of the utility model provided in this specification.

[0133] Figure 1 It is a schematic structural diagram of the specific implementation manner of the treatment system for phosphoric acid iron production wastewater of the present utility model.

[0134] Figure 2 It is a graph showing the water quality changes of each treatment unit in the phosphoric acid purification and recovery process in the specific implementation manner of the treatment method for phosphoric acid iron production wastewater of the present utility model.

[0135] Figure 3 It is a graph showing the water quality changes of each treatment unit in the produced water preparation process for reuse in the specific implementation manner of the treatment method for phosphoric acid iron production wastewater of the present utility model.

[0136] Figure 4 It is a graph showing the water quality changes of each treatment unit in the deep purification and discharge process in the specific implementation manner of the treatment method for phosphoric acid iron production wastewater of the present utility model.

[0137] The relevant markings in the above-mentioned accompanying drawings are as follows:

[0138] 100 - Washing water storage tank, 111 - Precision filter, 112 - First filter press, 113 - Filtrate storage tank, 114 - Slurry storage tank, 120 - Plate heat exchanger, 131 - Resin adsorption tower, 132 - Graphite diluter, 1331 - First pipeline, 1332 - Second pipeline, 134 - Post - adsorption liquid storage tank, 135 - Dilute sulfuric acid storage tank, 136 - Resin regeneration liquid storage tank, 137 - Eluent storage tank, 138 - Pure water storage tank, 141 - Ultrafiltration equipment, 142 - Ultrafiltration filtrate storage tank, 151 - First reverse osmosis equipment, 152 - Second reverse osmosis equipment, 153 - Concentrated phosphoric acid storage tank, 154 - Recycled phosphoric acid storage tank, 155 - First clear liquid storage tank, 210 - pH adjustment tank, 221 - First mixture storage tank, 222 - First - stage reverse osmosis equipment, 223 - Second - stage reverse osmosis equipment, 224 - Third - stage reverse osmosis equipment, 225 - First - stage concentrated water storage tank, 226 - Two - stage product water storage tank, 227 - Impurity concentrated liquid storage tank, 228 - Recycled product water storage tank, 231 - Sand filter tank, 232 - Activated carbon tank, 233 - Backwash water storage tank, 234 - Third pipeline, 235 - Fourth pipeline, 310 - Reaction mother liquor storage tank, 320 - Homogenization tank, 331 - Chemical reaction tank, 332 - Flocculation tank, 333 - Sludge tank, 334 - Second filter press, 335 - Silo, 336 - Pulping tank, 341 - pH adjustment pool, 342 - Fenton reaction pool, 343 - Inclined plate sedimentation tank, 344 - pH callback pool. Detailed implementation manners

[0139] The following clearly and completely describes the embodiments of the utility model provided in this specification in conjunction with the accompanying drawings. Those of ordinary skill in the art will be able to implement the embodiments of the utility model provided in this specification based on these descriptions. Before describing the embodiments of the utility model provided in this specification in conjunction with the accompanying drawings, it is particularly noted that:

[0140] In the embodiments of the utility model provided in this specification, the technical solutions and technical features provided in each part including the following descriptions can be combined with each other without conflict.

[0141] In addition, the embodiments of the embodiments of the utility model provided in this specification usually only represent a part of the embodiments of the utility model provided in this specification rather than all the embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the utility model provided in this specification shall fall within the scope of protection of the embodiments of the utility model provided in this specification.

[0142] Regarding the terms and units in the embodiments of the utility model creation provided in this specification: In the specification, claims, and relevant parts of the embodiments of the utility model creation provided in this specification, the terms "include", "comprise", "have", and any variations thereof are intended to cover non-exclusive inclusion. In addition, other relevant terms and units in the embodiments of the utility model creation provided in this specification can be reasonably interpreted based on the relevant content of the embodiments of the utility model creation provided in this specification.

[0143] The specific implementation manner of the treatment method for the iron phosphate production wastewater of the present utility model includes the following steps:

[0144] (1) Recycling the phosphoric acid purification and recovery process, including: successively pre-treating the washing water, and the pre-treatment includes filtration treatment, cooling treatment, resin adsorption treatment, and ultrafiltration treatment to obtain an ultrafiltration clear liquid; performing phosphoric acid recovery treatment on the ultrafiltration clear liquid to obtain recycled phosphoric acid and a first clear liquid; specifically as follows:

[0145] Step110, performing filtration treatment on the washing water to remove larger particulate matters and suspended matters to obtain a filtrate with SS ≤ 2 mg / L;

[0146] Step120, performing cooling treatment on the filtrate to adapt to the treatment effect of subsequent processes to obtain a coolant with a temperature after cooling treatment ≤ 35°C;

[0147] Step130, performing resin adsorption treatment on the coolant to remove metals such as iron, manganese, and copper to obtain an adsorbed liquid;

[0148] Step140, performing ultrafiltration treatment on the adsorbed liquid to remove larger particulate matters and suspended matters to obtain an ultrafiltration clear liquid; among them, the resin adsorption treatment uses a strong acid cation resin; the resin used in the resin adsorption treatment is regenerated with dilute sulfuric acid with a mass fraction of 8 - 10%, and the resin regeneration liquid with a sulfuric acid mass fraction of 6 - 7% obtained enters the second mixture; the regenerated resin is rinsed with pure water, and the rinsing water obtained is refluxed to be mixed with the washing water and then subjected to filtration treatment;

[0149] Step150, performing reverse osmosis membrane concentration treatment on the ultrafiltration clear liquid to obtain a phosphoric acid concentrate with a mass fraction of 8 - 10% and a purity ≥ 96% and a first produced water;

[0150] Step160, performing reverse osmosis membrane concentration treatment on the phosphoric acid concentrate to obtain recycled phosphoric acid with a mass fraction of 20 - 85% and a second produced water; among them, the first produced water and the second produced water constitute the first clear liquid.

[0151] Among them, the TDS of the washing water ≤ 16500 mg / L, the phosphoric acid concentration ≤ 16200 mg / L, the sulfate ion concentration ≤ 150 mg / L, the sodium ion concentration ≤ 15 mg / L, the total iron ion concentration ≤ 30 mg / L, the manganese ion concentration ≤ 30 mg / L, the calcium ion concentration ≤ 3 mg / L, the magnesium ion concentration ≤ 0.5 mg / L, the copper ion concentration ≤ 1 mg / L, the zinc ion concentration ≤ 0.5 mg / L, the silicon element concentration ≤ 28 mg / L, the fluoride ion concentration ≤ 14 mg / L; the temperature of the washing water is 60 °C, and SS ≤ 50 mg / L.

[0152] The TDS of the ultrafiltration filtrate ≤ 16500 g / L, the phosphoric acid concentration ≤ 16200 mg / L, the sulfate ion concentration ≤ 150 mg / L, the sodium ion concentration ≤ 15 mg / L, the total iron ion concentration ≤ 0.5 mg / L, the manganese ion concentration ≤ 0.5 mg / L, the calcium ion concentration ≤ 0.5 mg / L, the magnesium ion concentration ≤ 0.5 mg / L, the copper ion concentration ≤ 0.5 mg / L, the zinc ion concentration ≤ 0.5 mg / L, the silicon element concentration ≤ 28 mg / L, the fluoride ion concentration ≤ 14 mg / L.

[0153] The TDS of the recycled phosphoric acid ≤ 95000 mg / L, the phosphoric acid concentration ≤ 94000 mg / L, the sulfate ion concentration ≤ 610 mg / L, the sodium ion concentration ≤ 60 mg / L, the total iron ion concentration ≤ 3 mg / L, the manganese ion concentration ≤ 3 mg / L, the calcium ion concentration ≤ 3 mg / L, the magnesium ion concentration ≤ 3 mg / L, the copper ion concentration ≤ 3 mg / L, the zinc ion concentration ≤ 2.5 mg / L, the silicon element concentration ≤ 140 mg / L, the fluoride ion concentration ≤ 20 mg / L.

[0154] (2) The process for preparing recycled product water includes: adjusting the pH of the first clear liquid with an alkali solution to obtain raw water; concentrating the first mixture including the raw water and makeup water to obtain impurity concentrated liquid and recycled product water; specifically as follows:

[0155] Step210, adjusting the pH of the first clear liquid with a sodium hydroxide solution with a mass fraction of 32% to obtain raw water with a pH of 6 - 7;

[0156] Step220, performing reverse osmosis membrane concentration treatment on the first mixture to obtain first-stage concentrated water and first-stage product water;

[0157] Step230, performing reverse osmosis membrane concentration treatment on the first-stage concentrated water to obtain impurity concentrated liquid and second-stage product water;

[0158] Step240, performing reverse osmosis membrane concentration treatment on the first-stage product water and the second-stage product water to obtain second-stage concentrated water and recycled product water; among them, the second-stage concentrated water is refluxed to the first mixture.

[0159] Step 250, use a portion of the concentrated impurity solution to backwash the sand filter tank used for sand filtration treatment and the activated carbon tank used for activated carbon adsorption to obtain backwash water.

[0160] Among them, after subjecting tap water to sand filtration treatment and activated carbon adsorption in sequence, the makeup water is obtained. The TDS of the makeup water ≤ 250 mg / L, the sulfate ion concentration ≤ 160 mg / L, the sodium ion concentration ≤ 12 mg / L, the calcium ion concentration ≤ 50 mg / L, the magnesium ion concentration ≤ 9 mg / L, and the silicon element concentration ≤ 9 mg / L.

[0161] The TDS of the raw water ≤ 1100 mg / L, the phosphoric acid concentration ≤ 860 mg / L, the sulfate ion concentration ≤ 7 mg / L, the sodium ion concentration ≤ 210 mg / L, the total iron ion concentration ≤ 0.05 mg / L, the manganese ion concentration ≤ 0.05 mg / L, the calcium ion concentration ≤ 0.05 mg / L, the magnesium ion concentration ≤ 0.05 mg / L, the copper ion concentration ≤ 0.05 mg / L, the zinc ion concentration ≤ 0.04 mg / L, the silicon element concentration ≤ 2.5 mg / L, and the fluoride ion concentration ≤ 13 mg / L.

[0162] The TDS of the concentrated impurity solution ≤ 14200 mg / L, the phosphoric acid concentration ≤ 9400 mg / L, the sulfate ion concentration ≤ 1500 mg / L, the sodium ion concentration ≤ 2400 mg / L, the total iron ion concentration ≤ 0.5 mg / L, the manganese ion concentration ≤ 0.5 mg / L, the calcium ion concentration ≤ 400 mg / L, the magnesium ion concentration ≤ 75 mg / L, the copper ion concentration ≤ 0.5 mg / L, the zinc ion concentration ≤ 0.4 mg / L, the silicon element concentration ≤ 90 mg / L, and the fluoride ion concentration ≤ 110 mg / L.

[0163] (3) Deep purification and discharge process, including: purifying the second mixture including the concentrated impurity solution, reaction mother liquor, and resin regeneration liquor to obtain qualified product water; specifically as follows:

[0164] Step 310, add a sodium hydroxide solution with a mass fraction of 32% and a calcium hydroxide solution with a mass fraction of 15% (precipitant) to the second mixture, then perform flocculation sedimentation and solid-liquid separation treatment to obtain a second clear liquid;

[0165] Step 320, adjust the pH of the second clear liquid to 4 - 5 with sulfuric acid with a mass fraction of 30% to obtain a third clear liquid;

[0166] Step 330, perform Fenton oxidation treatment on the third clear liquid with a ferrous sulfate solution with a mass fraction of 30% and a hydrogen peroxide solution with a mass fraction of 30%, then perform flocculation sedimentation and solid-liquid separation treatment to obtain a fourth clear liquid;

[0167] Step 340, adjust the pH of the fourth clear liquid to 6 - 9 with an alkali solution to obtain qualified product water.

[0168] Among them, the TDS of the resin regeneration liquid is ≤ 100000 mg / L, the sulfate ion concentration is ≤ 95000 mg / L, the total iron ion concentration is ≤ 2450 mg / L, the manganese ion concentration is ≤ 2200 mg / L, the calcium ion concentration is ≤ 165 mg / L, the magnesium ion concentration is ≤ 30 mg / L, the copper ion concentration is ≤ 80 mg / L, and the zinc ion concentration is ≤ 21 mg / L.

[0169] The TDS of the reaction mother liquor is ≤ 188000 mg / L, the phosphoric acid concentration is ≤ 168000 mg / L, the sulfate ion concentration is ≤ 15900 mg / L, the sodium ion concentration is ≤ 1450 mg / L, the total iron ion concentration is ≤ 30 mg / L, the manganese ion concentration is ≤ 30 mg / L, the calcium ion concentration is ≤ 2.8 mg / L, the magnesium ion concentration is ≤ 0.5 mg / L, the copper ion concentration is ≤ 1 mg / L, the zinc ion concentration is ≤ 0.5 mg / L, the silicon element concentration is ≤ 1150 mg / L, and the fluoride ion concentration is ≤ 520 mg / L.

[0170] The TDS of the second mixture is ≤ 54000 mg / L, the phosphoric acid concentration is ≤ 36000 mg / L, the sulfate ion concentration is ≤ 14500 mg / L, the sodium ion concentration is ≤ 2000 mg / L, the total iron ion concentration is ≤ 330 mg / L, the manganese ion concentration is ≤ 300 mg / L, the calcium ion concentration is ≤ 330 mg / L, the magnesium ion concentration is ≤ 60 mg / L, the copper ion concentration is ≤ 12 mg / L, the zinc ion concentration is ≤ 4 mg / L, the silicon element concentration is ≤ 220 mg / L, and the fluoride ion concentration is ≤ 150 mg / L.

[0171] The flocculants used for flocculation sedimentation are PAM and / or PAC. The total iron ion refers to Fe 3+ and Fe 2+ .

[0172] Among them, the third clarified liquid has reached the third-level discharge standard of the Comprehensive Wastewater Discharge Standard (GB 8978-1996). All kinds of pollutants in the obtained qualified product water are not detected, achieving zero discharge, and can also be directly discharged or recycled to the water-required sections in the system.

[0173] In order to implement the above-mentioned treatment method for iron phosphate production wastewater, the specific implementation manner of the treatment system for iron phosphate production wastewater adopted by the present utility model is as follows.

[0174] Figure 1 It is a structural schematic diagram of the specific implementation manner of the treatment system for iron phosphate production wastewater of the present utility model.

[0175] As Figure 1 shown, the treatment system for iron phosphate production wastewater includes a recycled phosphoric acid purification and recovery section, a recycled product water preparation section, and a deep purification and discharge section.

[0176] The recycled phosphoric acid purification and recovery section is used to treat washing water to obtain recycled phosphoric acid and a first clear liquid. The recycled phosphoric acid purification and recovery section includes a filtration unit, a heat exchange unit, a resin adsorption unit, an ultrafiltration unit, and a phosphoric acid concentration unit.

[0177] The filtration unit filters the washing water and outputs a filtrate. The filtration unit includes a precision filter 111 and a first filter press 112. The precision filter 111 filters the washing water to obtain a filtrate and a filter cake. The filtrate is stored in a filtrate storage tank 113, and the slag liquid formed by backblowing and collecting the filter cake is stored in a slag liquid storage tank 114. The first filter press 112 filters the slag liquid and the first filtrate obtained is returned to the washing water storage tank 100.

[0178] The heat exchange unit cools the filtrate and outputs a coolant. The heat exchange unit includes a plate heat exchanger 120.

[0179] The resin adsorption unit adsorbs the coolant and outputs an adsorbed liquid. The resin adsorption unit includes a resin adsorption tower 131, a resin regeneration mechanism, and a resin washing mechanism. Strong acid cation resin is provided in the resin adsorption tower 131. The resin regeneration mechanism sprays and regenerates the strong acid cation resin with dilute sulfuric acid to obtain a resin regeneration liquid. The resin regeneration mechanism includes a graphite diluter 132, and the graphite diluter 132 processes pure water and concentrated sulfuric acid to obtain dilute sulfuric acid for spray regeneration. The resin washing mechanism washes the strong acid cation resin with pure water, and the washing liquid obtained is returned to the washing water storage tank 100. The resin washing mechanism includes a first pipeline 1331 for inputting pure water into the graphite diluter 132 and a second pipeline 1332 for inputting pure water into the resin adsorption tower 131. The resin adsorption unit further includes an adsorbed liquid storage tank 134, a concentrated sulfuric acid storage tank, a dilute sulfuric acid storage tank 135, a resin regeneration liquid storage tank 136, a washing liquid storage tank 137, and a pure water storage tank 138.

[0180] The ultrafiltration unit ultrafilters the adsorbed liquid and outputs an ultrafiltration clear liquid. The ultrafiltration unit includes an ultrafiltration device 141 and an ultrafiltration clear liquid storage tank 142. The ultrafiltration device 141 uses an internal pressure type hollow PES membrane sheet. The ultrafiltration concentrate obtained by filtering the adsorbed liquid by the ultrafiltration unit is returned to the washing water storage tank 100.

[0181] The phosphoric acid concentration unit concentrates the ultrafiltration filtrate and outputs recycled phosphoric acid and the first clear liquid. The phosphoric acid concentration unit includes a first reverse osmosis device 151 and a second reverse osmosis device 152. The first reverse osmosis device 151 concentrates the ultrafiltration filtrate to obtain a concentrated phosphoric acid solution and a first produced water; the second reverse osmosis device 152 concentrates the concentrated phosphoric acid solution to obtain recycled phosphoric acid and a second produced water; wherein, the first produced water and the second produced water constitute the first clear liquid. The phosphoric acid concentration unit further includes a concentrated phosphoric acid storage tank 153, a recycled phosphoric acid storage tank 154, and a first clear liquid storage tank 155.

[0182] The recycled produced water preparation section is used to treat the first clear liquid to obtain a concentrated impurity liquid and recycled produced water. The recycled produced water preparation section includes a pH adjustment unit, an impurity concentration unit, a makeup water unit, and a backwashing unit.

[0183] The pH adjustment unit adjusts the pH of the first clear liquid and outputs raw water. The pH adjustment unit includes a pH adjustment tank 210 and a first sodium hydroxide dosing device for dosing sodium hydroxide into the pH adjustment tank 210.

[0184] The impurity concentration unit concentrates a first mixture including raw water and makeup water and outputs a concentrated impurity liquid and recycled produced water. The impurity concentration unit includes a first mixture storage tank 221, a first-stage reverse osmosis device 222, a second-stage reverse osmosis device 223, and a third-stage reverse osmosis device 224. The first-stage reverse osmosis device 222 concentrates the first mixture to obtain a first-stage concentrated water and a first-stage produced water; the second-stage reverse osmosis device 223 concentrates the first-stage concentrated water to obtain a concentrated impurity liquid and a second-stage produced water; the third-stage reverse osmosis device 224 concentrates the first-stage produced water and the second-stage produced water to obtain a second-stage concentrated water and recycled produced water; wherein, the second-stage concentrated water is refluxed to the first mixture storage tank 221. The impurity concentration unit further includes a first-stage concentrated water storage tank 225, a two-stage produced water storage tank 226, a concentrated impurity liquid storage tank 227, a recycled produced water storage tank 228, and the first-stage produced water and the second-stage produced water are stored in the two-stage produced water storage tank 226.

[0185] The makeup water unit is used to input makeup water into the impurity concentration unit. The makeup water unit includes a tap water storage tank and a sand filter tank 231 and an activated carbon tank 232 for treating tap water.

[0186] The backwashing unit is used to wash the sand filter tank 231 and the activated carbon tank 232. The backwashing unit includes a third pipeline 234 connecting the concentrated impurity liquid storage tank 227 and the sand filter tank 231, a fourth pipeline 235 connecting the concentrated impurity liquid storage tank 227 and the activated carbon tank 232, and a backwashing water storage tank 233100 for storing the backwashing water formed by washing.

[0187] The deep purification and discharge section is used to purify a second mixture including impurity concentrated solution, reaction mother liquor (from the reaction mother liquor storage tank 310), resin regeneration liquid, and backwash water to obtain qualified product water. The deep purification and discharge section includes a homogenization unit, a softening unit, and an organic matter degradation unit.

[0188] The homogenization unit is used to mix the impurity concentrated solution, reaction mother liquor, and resin regeneration liquid to obtain a second mixture. The homogenization unit includes a homogenization tank 320, and the impurity concentrated solution, reaction mother liquor, resin regeneration liquid, and backwash water are mixed in the homogenization tank 320 to form a second mixture.

[0189] The softening unit is used to remove impurity ions from the second mixture and output a second clear liquid. The softening unit includes a chemical reaction tank 331, a flocculation tank 332, a sludge tank 333, a second filter press 334, a precipitant dosing device for dosing a precipitant into the chemical reaction tank 331, and a first flocculant dosing device for dosing a flocculant into the flocculation tank 332. The precipitant dosing device includes a second sodium hydroxide dosing device and a calcium hydroxide dosing device, and the calcium hydroxide dosing device includes a bin 335 for storing quicklime or slaked lime and a pulp making tank 336 for making calcium hydroxide slurry.

[0190] The organic matter degradation unit is used to remove organic matter from the second clear liquid and output qualified product water. The organic matter degradation unit includes a pH adjustment tank 341, a Fenton reaction tank 342, a sedimentation tank, a pH callback tank 344, an acid dosing device for dosing acid liquid into the pH adjustment tank 341, a ferrous sulfate dosing device for dosing ferrous sulfate into the Fenton reaction tank 342, a hydrogen peroxide dosing device for dosing hydrogen peroxide into the Fenton reaction tank 342, a second flocculant dosing device for dosing a flocculant into the sedimentation tank, and a third sodium hydroxide dosing device for dosing sodium hydroxide into the pH callback tank 344. The sedimentation tank is an inclined plate sedimentation tank 343, and the sludge deposited in the inclined plate sedimentation tank 343 flows into the second filter press 334.

[0191] The beneficial effects of the present invention are illustrated by the following specific application examples.

[0192] First, in the process of recycling phosphoric acid purification and recovery, the Figure 1 recycling phosphoric acid purification and recovery section in is used to treat the washing water. Through the collaborative cooperation of the filtration unit, heat exchange unit, resin adsorption unit, ultrafiltration unit, and phosphoric acid concentration unit, the phosphoric acid resources in the washing water are effectively enriched in the recycled phosphoric acid. The water quality changes of each treatment unit in this process are shown in Figure 2 .

[0193] Then, for the first clear liquid composed of the first product water and the second product water, the Figure 1It is processed in the recycled product water preparation section. The obtained recycled product water has a large quantity, with a TDS content as low as 0.8 mg / L and a sulfate content as low as 0.55 mg / L, and can be recycled to the iron phosphate synthesis process or other processes. The water quality changes of each treatment unit in this process are shown in Figure 3 .

[0194] Finally, for the second mixture composed of all by-product wastewater and reaction mother liquor generated in the recycled phosphoric acid purification and recovery process and the recycled product water preparation process, Figure 1 is used for treatment in the deep purification and discharge section. Among them, the dosage of sodium hydroxide solution in the chemical reaction tank 331 is 0.081 m 3 / h, the dosage of calcium hydroxide solution is 0.432 m 3 / h, the dosage of sulfuric acid in the pH adjustment tank 341 is 0.1 m 3 / h, the dosage of ferrous sulfate solution in the Fenton reaction tank 342 is 11.83 m 3 / h, and the dosage of hydrogen peroxide solution is 6.13 m 3 / h, ultimately enabling the deep removal of pollutants. The water quality changes of each treatment unit in this process are shown in Figure 4 .

[0195] It is verified that by using the treatment method and treatment system of the present utility model to treat iron phosphate production wastewater, the benefits brought by the recycled phosphoric acid and recycled product water are significant, far higher than the equipment investment and operation cost of the treatment system, and ultimately bring excellent economic benefits to the enterprise, and it is very suitable for use by iron phosphate production enterprises.

[0196] The above has described the relevant content of the embodiments of the utility model provided in this specification. Those of ordinary skill in the art will be able to implement the embodiments of the utility model provided in this specification based on these descriptions. Based on the above content of the embodiments of the utility model provided in this specification, all other preferred embodiments and examples obtained by those of ordinary skill in the art without creative efforts shall fall within the scope protected by the embodiments of the utility model provided in this specification.

Claims

1. A treatment system for wastewater from ferric phosphate production, characterized by: include: The reuse phosphoric acid purification and recovery section is used to treat the wash water to obtain the reuse phosphoric acid and the first clear liquid; The recycled produced water preparation section is used to treat the first clear liquid to obtain an impurity concentrated liquid and recycled produced water; The deep purification and discharge section is used to purify the impurity concentrate and reaction mother liquor to obtain qualified produced water; Wherein, the reused water preparation section includes: A pH adjustment unit, wherein the pH adjustment unit adjusts the pH of the first clear liquid and then outputs raw water; An impurity concentration unit, wherein the impurity concentration unit concentrates the first mixture including raw water and makeup water and then outputs an impurity concentrate and recycled produced water; A water replenishment unit is used to input replenishment water into the impurity concentration unit.

2. The system for treating wastewater from iron phosphate production according to claim 1, characterized in that: The pH adjustment unit comprises a pH adjustment tank (210) and a first sodium hydroxide adding device for adding sodium hydroxide into the pH adjustment tank (210).

3. The system for treating wastewater from iron phosphate production according to claim 1, characterized in that: The impurity concentration unit comprises a first mixture storage tank (221) and: A primary reverse osmosis device (222), wherein the primary reverse osmosis device (222) performs a concentration treatment on the first mixture to obtain primary concentrated water and primary produced water; A secondary reverse osmosis device (223), wherein the secondary reverse osmosis device (223) performs a concentration treatment on the primary concentrated water to obtain an impurity concentrated solution and secondary produced water; A three-stage reverse osmosis device (224) is provided, wherein the three-stage reverse osmosis device (224) performs concentration treatment on the primary produced water and the secondary produced water to obtain secondary concentrated water and recycled produced water; wherein the secondary concentrated water flows back into the first mixture storage tank (221).

4. The system for treating wastewater from ferric phosphate production as claimed in claim 3, characterized in that: The impurity concentration unit further comprises a primary concentrated water storage tank (225), a two-stage produced water storage tank (226), an impurity concentrated liquid storage tank (227), and a recycled produced water storage tank (228), wherein the primary produced water and the secondary produced water are stored in the two-stage produced water storage tank (226).

5. The system for treating wastewater from ferric phosphate production according to claim 1, characterized in that: The water replenishment unit comprises a tap water storage tank, a sand filter tank (231) for treating the tap water, and an activated carbon tank (232).

6. The system for treating wastewater from ferric phosphate production as claimed in claim 5, characterized in that: The recycled water preparation section also includes a backwash unit for flushing the sand filter tank (231) and the activated carbon tank (232).

7. The system for treating wastewater from ferric phosphate production according to claim 6, characterized in that: The backwash unit comprises a third pipeline (234) connecting the impurity concentrate storage tank (227) and the sand filter tank (231), a fourth pipeline (235) connecting the impurity concentrate storage tank (227) and the activated carbon tank (232), and a backwash water storage tank (233) (100) for storing backwash water formed by flushing.

8. The system for treating wastewater from ferric phosphate production according to claim 7, characterized in that: The reuse phosphoric acid purification and recovery section includes: A filtering unit, wherein the filtering unit filters the wash water and outputs a filtrate; A heat exchange unit, wherein the heat exchange unit cools the filtrate and then outputs a coolant; A resin adsorption unit, wherein the resin adsorption unit performs adsorption treatment on the coolant and then outputs adsorbed liquid; An ultrafiltration unit, wherein the ultrafiltration unit performs ultrafiltration treatment on the adsorbed liquid and outputs ultrafiltration clear liquid; A phosphoric acid concentration unit, wherein the phosphoric acid concentration unit concentrates the ultrafiltration clear liquid and outputs the reused phosphoric acid and the first clear liquid; The deep purification discharge section includes a homogenizing unit, which is used to mix the impurity concentrate, the reaction mother liquor, the resin regeneration liquid and the backwash water into a second mixture.

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