Iron phosphate wastewater treatment system
By combining bipolar membrane electrodialysis technology and multi-stage reverse osmosis filtration devices, the problems of high raw material input and high energy consumption in the treatment of ferric phosphate wastewater have been solved, achieving efficient resource utilization and low-cost treatment, and improving economic benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 山东锂源科技有限公司
- Filing Date
- 2025-05-07
- Publication Date
- 2026-05-08
AI Technical Summary
Existing methods for treating ferric phosphate wastewater suffer from high raw material input costs, high energy consumption, and poor economic benefits. In particular, wastewater containing heavy metal ions generated during the ammonia synthesis of ferric phosphate is difficult to treat effectively.
The mother liquor concentrate is separated into ammonia and sulfuric acid using bipolar membrane electrodialysis technology, and then recycled back to the front-end reaction tank. Combined with multi-stage reverse osmosis and filtration devices, this achieves efficient resource utilization and efficient preparation of pure water.
It reduced the raw material input cost for wastewater treatment, improved the economic benefits of ammonium sulfate, and achieved low-energy consumption treatment through a highly automated system, thereby improving treatment efficiency.
Smart Images
Figure CN224212533U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a wastewater treatment system, and more particularly to a ferric phosphate wastewater treatment system. Background Technology
[0002] With the development of the new energy industry, the market demand for lithium iron phosphate batteries has increased significantly. The cathode material for lithium iron phosphate batteries is mostly produced using the ammonia process. This process generates a large amount of wastewater containing heavy metal ions. The wastewater mainly contains high concentrations of heavy metals such as nitrogen, phosphorus, fluorine, iron, and manganese, as well as alkaline earth metals such as magnesium, and small amounts of other heavy metals such as nickel, cobalt, and zinc, and some fluoride ions. Treatment is extremely difficult, and improper treatment methods can cause significant environmental pollution and the loss of metal resources. Currently, the main recovery and treatment method involves pretreating the mother liquor and washing liquid separately, followed by membrane concentration. The membrane permeate is used to produce pure water for reuse, and the concentrated water is fed into an evaporation crystallization system (MVR) for further concentration to produce ammonium salts for sale. This method requires the addition of a large amount of ammonia water to react with the washing solution or mother liquor during pretreatment to remove phosphate ions and metal ions. When the filtered solution enters the reverse osmosis membrane (RO) for filtration, sulfuric acid needs to be added to adjust the pH value in order to ensure the filtration effect, which increases the raw material input cost. Furthermore, the concentrated water is treated in the evaporation crystallization system (MVR), which is time-consuming, labor-intensive, and energy-intensive, and the quality of the produced ammonium sulfate is not high, resulting in poor economic benefits. Utility Model Content
[0003] Purpose of the utility model: The purpose of this utility model is to reduce the input cost of raw materials in the treatment of ferric phosphate wastewater and to provide a ferric phosphate wastewater treatment system.
[0004] Technical solution: The ferric phosphate wastewater treatment system of this utility model includes a washing liquid treatment unit and a mother liquor treatment unit, and further includes a bipolar membrane electrodialysis unit for separating the concentrated mother liquor in the mother liquor treatment unit into ammonia water and sulfuric acid.
[0005] The washing solution treatment unit includes a washing solution buffer tank, a primary washing solution reaction tank, a primary washing solution pressure filter, a secondary washing solution reaction tank, a secondary washing solution pressure filter, a multi-media filtration device, an ultrafiltration device, and a reverse osmosis device connected in sequence.
[0006] The mother liquor treatment unit comprises, in sequence, a mother liquor buffer tank, a primary mother liquor reaction tank, a primary mother liquor filter press, a secondary mother liquor reaction tank, a secondary mother liquor filter press, a multi-media mother liquor filter, a mother liquor ultrafiltration device, and a high-pressure reverse osmosis mother liquor device. The permeate output of the high-pressure reverse osmosis mother liquor device is connected to the washing liquid reverse osmosis device; the concentrated water output of the high-pressure reverse osmosis mother liquor device is connected to a bipolar membrane electrodialysis unit; the ammonia output of the bipolar membrane electrodialysis unit is separately connected to the primary washing liquid reaction tank, the secondary washing liquid reaction tank, the primary mother liquor reaction tank, and the secondary mother liquor reaction tank; the concentrated water output of the washing liquid reverse osmosis device is connected to the high-pressure reverse osmosis mother liquor device; and the sulfuric acid output of the bipolar membrane electrodialysis unit is separately connected to the multi-media washing liquid filter and the multi-media mother liquor filter.
[0007] Furthermore, the primary and secondary reaction tanks of the washing solution, the primary and secondary reaction tanks of the mother liquor, are each equipped with an ammonia metering pump to control the ammonia return flow rate; the multi-media filtration devices of the washing solution and the mother liquor are each equipped with a sulfuric acid metering pump to control the sulfuric acid return flow rate. The bipolar membrane electrodialysis unit separates ammonia and sulfuric acid from the concentrated mother liquor water. The ammonia is recycled back to the primary and secondary reaction tanks of the washing solution, the primary and secondary reaction tanks of the mother liquor, and the sulfuric acid is recycled back to the multi-media filtration devices of the washing solution and the mother liquor, achieving efficient resource utilization.
[0008] Furthermore, pH meters are installed in the primary and secondary reaction tanks of the washing solution, the primary reaction tank of the mother liquor, and the secondary reaction tank of the mother liquor to monitor the pH value within each tank. These pH meters are interlocked with ammonia metering pumps in each stage of the washing solution and mother liquor treatment units. Monitoring the pH value within the reaction tanks with the pH meters controls the ammonia reflux flow rate, maintaining the pH value of the primary reaction tank of the washing solution and the primary reaction tank of the mother liquor at 3.0–4.0 to ensure the removal efficiency of phosphate ions within the reaction tanks; and maintaining the pH value of the secondary reaction tank of the washing solution and the secondary reaction tank of the mother liquor at 8.5–9.0 to ensure the removal efficiency of metal ions within the reaction tanks.
[0009] Furthermore, the washing liquid reverse osmosis unit and the mother liquor high-pressure reverse osmosis unit are each equipped with a pH meter for monitoring the pH value within the unit. The pH meter is interlocked with the sulfuric acid metering pumps of the washing liquid treatment unit and the mother liquor treatment unit, respectively. Monitoring the pH value within the unit with the pH meter is used to control the sulfuric acid reflux rate, adjusting the pH value of the washing liquid reverse osmosis unit and the mother liquor high-pressure reverse osmosis unit to 5.0–6.0. This improves the reverse osmosis effect while simultaneously regulating the pH value and conductivity of the pure water produced after staged filtration by the washing liquid reverse osmosis unit.
[0010] Furthermore, an activated carbon filter and a chelating resin tower for impurity removal are provided between the mother liquor treatment unit and the bipolar membrane electrodialysis unit. The activated carbon filter adsorbs and removes organic matter and large colloids from the water, while the chelating resin tower removes residual metal ions such as iron, manganese, calcium, and magnesium from the water, ensuring the removal efficiency of impurity ions in the concentrated water and preventing metal ions from scaling on the bipolar membrane.
[0011] Furthermore, the washing liquid reverse osmosis device includes a first-stage reverse osmosis module, a second-stage reverse osmosis module, and a third-stage reverse osmosis module. The product water output end of the mother liquor high-pressure reverse osmosis device is connected to the first-stage reverse osmosis module. The concentrated water output end of the first-stage reverse osmosis module is connected to the mother liquor high-pressure reverse osmosis device. The concentrated water from the second-stage and third-stage reverse osmosis modules is returned to the previous stage reverse osmosis module for further filtration, ensuring that the conductivity of the output pure water meets the requirements.
[0012] Beneficial effects: Compared with the prior art, this utility model has the following advantages: 1. The bipolar membrane electrodialysis technology replaces the MVR technology to further remove impurities from the ammonium sulfate solution, which has low quality after reverse osmosis membrane concentration, to prepare ammonia and sulfuric acid. The prepared ammonia and sulfuric acid can then be reused in the front-end wastewater treatment process, reducing the raw material input cost of wastewater treatment and improving the economic benefits of ammonium sulfate recovery; 2. The system has a high degree of automation in wastewater treatment, saves time and labor, has low energy consumption, and reduces the enterprise's wastewater treatment cost. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation
[0014] The technical solution of this utility model will be further described below with reference to the accompanying drawings.
[0015] like Figure 1 The illustrated ferric phosphate wastewater treatment system includes a washing liquid treatment unit and a mother liquor treatment unit, as well as a bipolar membrane electrodialysis unit that separates the concentrated mother liquor in the mother liquor treatment unit into ammonia and sulfuric acid.
[0016] The washing solution treatment unit includes a washing solution buffer tank, a washing solution primary reaction tank, a washing solution primary pressure filter, a washing solution secondary reaction tank, a washing solution secondary pressure filter, a washing solution multi-media filter, a washing solution ultrafiltration device, a primary reverse osmosis module, a secondary reverse osmosis module, and a tertiary reverse osmosis module connected in sequence. The concentrated water from the secondary and tertiary reverse osmosis modules is returned to the previous reverse osmosis module for further filtration.
[0017] The mother liquor treatment unit includes a mother liquor buffer tank, a primary mother liquor reaction tank, a primary mother liquor filter press, a secondary mother liquor reaction tank, a secondary mother liquor filter press, a multi-media mother liquor filter, a mother liquor ultrafiltration device, and a high-pressure reverse osmosis mother liquor unit connected in sequence. The permeate output of the high-pressure reverse osmosis mother liquor unit is connected to the primary reverse osmosis module of the washing liquid, and the concentrate output is connected to an activated carbon filter and a chelating resin tower. The concentrate output of the primary reverse osmosis module is connected to the high-pressure reverse osmosis mother liquor unit. The output of the chelating resin tower is connected to a bipolar membrane electrodialysis unit. The ammonia output of the bipolar membrane electrodialysis unit is separately connected to the primary washing liquid reaction tank, the secondary washing liquid reaction tank, the primary mother liquor reaction tank, and the secondary mother liquor reaction tank. The sulfuric acid output of the bipolar membrane electrodialysis unit is separately connected to the multi-media washing liquid filter and the multi-media mother liquor filter.
[0018] The washing solution primary reaction tank, washing solution secondary reaction tank, mother liquor primary reaction tank, and mother liquor secondary reaction tank are each equipped with an ammonia water metering pump for controlling the ammonia water return flow; the washing solution multi-media filtration device and the mother liquor multi-media filtration device are each equipped with a sulfuric acid metering pump for controlling the sulfuric acid return flow.
[0019] Each of the primary and secondary reaction tanks for washing liquid, mother liquor, and mother liquor is equipped with a pH meter for monitoring the pH value within the tank. These pH meters are interlocked with ammonia metering pumps in each stage of the washing liquid and mother liquor treatment units. Similarly, each of the primary reverse osmosis module and the mother liquor high-pressure reverse osmosis unit is equipped with a pH meter for monitoring the pH value within the unit. These pH meters are interlocked with sulfuric acid metering pumps in both the washing liquid and mother liquor treatment units to control the pH value within the unit to meet process requirements: maintaining the pH value of the primary reaction tanks for washing liquid and mother liquor at 3.0. The pH of the washing liquid secondary reaction tank and the mother liquor secondary reaction tank is controlled at 8.5-9.0 to remove heavy metal ions from the wastewater; the pH of the primary reverse osmosis module and the mother liquor high-pressure reverse osmosis device is controlled at 5.0-6.0 to improve the reverse osmosis effect while maintaining the pH of the pure water produced after filtration through the primary, secondary and tertiary reverse osmosis modules at 6.0-7.5 and the conductivity at around 10 μs / cm; the permeate output of the mother liquor high-pressure reverse osmosis device is connected to the washing liquid primary reverse osmosis module for recovery, with a recovery rate of about 50%. After being concentrated by the high-pressure reverse osmosis unit, the mother liquor is mainly an ammonium sulfate solution with a TDS of approximately 15 g / L. The concentrated water output of the high-pressure reverse osmosis unit is first connected to an activated carbon filter and a chelating resin tower for impurity removal: the activated carbon filter adsorbs and removes organic matter and large colloids from the water, while the chelating resin tower removes residual metal ions such as iron, manganese, calcium, and magnesium from the water, ensuring that the metal ions entering the bipolar membrane electrodialysis unit are less than 1 ppm, thereby preventing metal ion scaling on the bipolar membrane. After impurity removal, the ammonium sulfate solution enters the bipolar membrane electrodialysis unit to separate ammonia and sulfuric acid. The ammonia is recycled back to the washing liquid primary reaction tank, the washing liquid secondary reaction tank, the mother liquor primary reaction tank, and the mother liquor secondary reaction tank, while the sulfuric acid is recycled back to the washing liquid multi-media filtration device and the mother liquor multi-media filtration device, achieving efficient resource utilization.
Claims
1. A ferric phosphate wastewater treatment system, comprising a washing liquid treatment unit and a mother liquor treatment unit, characterized in that, It also includes a bipolar membrane electrodialysis unit that separates the concentrated mother liquor in the mother liquor treatment unit into ammonia and sulfuric acid; The washing solution treatment unit includes a washing solution buffer tank, a primary washing solution reaction tank, a primary washing solution pressure filter, a secondary washing solution reaction tank, a secondary washing solution pressure filter, a multi-media filtration device, an ultrafiltration device, and a reverse osmosis device connected in sequence. The mother liquor treatment unit comprises, in sequence, a mother liquor buffer tank, a primary mother liquor reaction tank, a primary mother liquor filter press, a secondary mother liquor reaction tank, a secondary mother liquor filter press, a multi-media mother liquor filter, a mother liquor ultrafiltration device, and a high-pressure reverse osmosis mother liquor device. The permeate output of the high-pressure reverse osmosis mother liquor device is connected to the washing liquid reverse osmosis device; the concentrated water output of the high-pressure reverse osmosis mother liquor device is connected to a bipolar membrane electrodialysis unit; the ammonia output of the bipolar membrane electrodialysis unit is separately connected to the primary washing liquid reaction tank, the secondary washing liquid reaction tank, the primary mother liquor reaction tank, and the secondary mother liquor reaction tank; the concentrated water output of the washing liquid reverse osmosis device is connected to the high-pressure reverse osmosis mother liquor device; and the sulfuric acid output of the bipolar membrane electrodialysis unit is separately connected to the multi-media washing liquid filter and the multi-media mother liquor filter.
2. The ferric phosphate wastewater treatment system according to claim 1, characterized in that, The washing liquid primary reaction tank, washing liquid secondary reaction tank, mother liquor primary reaction tank, and mother liquor secondary reaction tank are each equipped with an ammonia water metering pump for controlling the ammonia water return flow; the washing liquid multi-media filtration device and the mother liquor multi-media filtration device are each equipped with a sulfuric acid metering pump for controlling the sulfuric acid return flow.
3. The ferric phosphate wastewater treatment system according to claim 2, characterized in that, Each of the washing liquid primary reaction tank, washing liquid secondary reaction tank, mother liquor primary reaction tank, and mother liquor secondary reaction tank is equipped with a pH meter for monitoring the pH value in the tank. The pH meter is interlocked with the ammonia metering pump in each reaction tank of the washing liquid treatment unit and the mother liquor treatment unit.
4. The ferric phosphate wastewater treatment system according to claim 2, characterized in that, The washing liquid reverse osmosis device and the mother liquor high-pressure reverse osmosis device are respectively equipped with pH meters for monitoring the pH value inside the device, and the pH meters are interlocked with the sulfuric acid metering pumps of the washing liquid treatment unit and the mother liquor treatment unit, respectively.
5. The ferric phosphate wastewater treatment system according to claim 3, characterized in that, The pH value of the washing solution primary reaction tank and the mother liquor primary reaction tank is 3.0 to 4.
0.
6. The ferric phosphate wastewater treatment system according to claim 3, characterized in that, The pH value of the washing solution secondary reaction tank and the mother liquor secondary reaction tank is 8.5 to 9.
0.
7. The ferric phosphate wastewater treatment system according to claim 3, characterized in that, The pH value of the washing solution reverse osmosis device and the mother liquor high-pressure reverse osmosis device is 5.0 to 6.
0.
8. The ferric phosphate wastewater treatment system according to claim 1, characterized in that, The mother liquor treatment unit and the bipolar membrane electrodialysis unit are also equipped with an activated carbon filter and a chelating resin tower for impurity removal.
9. The ferric phosphate wastewater treatment system according to claim 1, characterized in that, The washing liquid reverse osmosis device includes a first-stage reverse osmosis module, a second-stage reverse osmosis module, and a third-stage reverse osmosis module. The product water output end of the mother liquor high-pressure reverse osmosis device is connected to the first-stage reverse osmosis module; the concentrated water output end of the first-stage reverse osmosis module is connected to the mother liquor high-pressure reverse osmosis device.