Ammonium chloride evaporation concentrated water pretreatment filter double-channel circulation system and method
By using a dual-channel circulation system for pretreatment and filtration of concentrated ammonium chloride evaporation water, the problems of filter clogging and crystallization blockage in the treatment of high-concentration, high-impurity ammonium chloride wastewater in the rare earth smelting carbon precipitation process were solved, achieving stable production and energy saving.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BAOTOU HUAMEI RE PRODS
- Filing Date
- 2026-04-24
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies for treating high-concentration, high-impurity ammonium chloride wastewater generated during the rare earth smelting carbon precipitation process suffer from problems such as filter clogging, low evaporation efficiency, and system crystallization blockage, leading to frequent shutdowns and high energy consumption, which affects production continuity and economy.
A dual-channel circulation system for pretreatment and filtration of concentrated ammonium chloride evaporation water is adopted, including a first circulation channel and a second circulation channel. The wastewater is transported to the MVR unit and the plate and frame filter press for treatment through a dual circulation switching valve to achieve solid-liquid separation and neutralization, and generate NH4Cl crystal products.
It effectively treats high-concentration, high-impurity ammonium chloride wastewater, reduces filter clogging frequency and system crystallization risk, ensures production stability, reduces energy consumption and maintenance costs, and improves production efficiency.
Smart Images
Figure CN122444362A_ABST
Abstract
Description
Technical Field
[0001] In the field of wastewater treatment technology of hydrometallurgy, specifically, it relates to a dual-channel circulation system and method for pretreatment and filtration of ammonium chloride evaporation concentrate. Background Technology
[0002] Ammonium chloride wastewater mainly originates from the carbon precipitation process in rare earth smelting and separation production. It is characterized by high ammonia nitrogen concentration, high salinity, and strong corrosiveness and pungent odor. High-concentration saline ammonium chloride wastewater is often generated during the rare earth smelting carbon precipitation process. Due to its high solubility, easy crystallization, and potential corrosiveness, this type of ammonium chloride wastewater is difficult to treat using conventional wastewater treatment technologies. Direct discharge would cause serious damage to the aquatic ecosystem.
[0003] Mechanical vapor recompression (MVR) technology has become a core process for treating this type of wastewater due to its high efficiency and energy saving characteristics. The ammonium chloride evaporation recovery process combines MVR with triple-effect evaporation and crystallization of the mother liquor, thereby achieving effective heat utilization, reducing operating costs, and realizing fully automated operation. However, when treating complex liquids with high solid content and many impurities (such as effluent from an evaporation accident tank), direct-feed MVR systems often face the following problems: insufficient pretreatment leading to clogging of subsequent filters, decreased evaporation efficiency, and locally excessively high salt concentrations within the system causing crystallization blockage in pipelines and equipment. These technical problems force frequent shutdowns for cleaning, severely restricting production continuity and economic efficiency. Summary of the Invention
[0004] The purpose of this invention is to provide a dual-channel circulation system and method for pretreatment and filtration of ammonium chloride evaporation concentrate, in order to solve the technical problems existing in the prior art.
[0005] To achieve the above objectives, the technical solution used in this invention is: The ammonium chloride evaporation concentrate pretreatment filtration dual-channel circulation system includes: An evaporation accident pool is used to collect ammonium chloride wastewater and accident liquid generated during the rare earth smelting carbon precipitation process. Its outlet is connected to the feed port of a dual circulation switching valve via a pipeline. The dual-circulation switching valve is used to transport ammonium chloride wastewater and emergency liquid to the first circulation channel and the second circulation channel respectively. The dual-circulation switching valve is equipped with an inlet port and two outlet ports. Each of the two outlet ports is equipped with a circulation pump. The two outlet ports are connected to the inlet of the first circulation channel and the second circulation channel respectively through pipelines. The first circulation channel uses steam mechanical recompression (MVR) technology to treat emergency fluid and MVR filtrate. The second circulation channel separates the ammonium chloride wastewater into solid and liquid components, and the treated MVR filtrate is then transported to the first circulation channel.
[0006] Furthermore, the first circulation channel includes: an evaporation emergency pool, an MVR feed tank, and an MVR unit; wherein... The MVR feed tank has its inlet connected to the discharge port of the dual circulation switching valve via a pipeline, and its outlet connected to the MVR unit via a pipeline for receiving emergency fluid. The MVR unit uses MVR technology to treat emergency fluid and MVR filtrate to produce NH4Cl crystals.
[0007] Furthermore, the second circulation channel includes: a pretreatment sludge tank, a plate and frame filter press, an ammonium chloride raw water tank, and an MVR feeding device, wherein... The pretreatment sludge tank has its inlet connected to the discharge port of the dual circulation switching valve via a pipeline, and its outlet connected to the inlet of the plate and frame filter press via a pipeline. It receives ammonium chloride wastewater from the evaporation accident tank and buffers, mixes, and flocculates the ammonium chloride wastewater. The plate and frame filter press has its outlet connected to the ammonium chloride raw water tank via a pipeline to receive ammonium chloride wastewater, perform solid-liquid separation on the ammonium chloride wastewater, transport the filtered plate and frame filtrate to the ammonium chloride raw water tank, and transport the filter cake off-site for disposal. The ammonium chloride raw water tank has its outlet connected to the MVR unit via a pipeline. It is used to receive plate and frame filtrate, neutralize it to form MVR filtrate, and then transport it to the MVR feed unit. The MVR feeder is used to deliver the MVR filtrate to the MVR unit.
[0008] Furthermore, filters are installed at the inlet of the MVR feed tank and the MVR unit to remove solid impurities mixed in with the emergency fluid.
[0009] A dual-channel circulation method for pretreatment filtration of ammonium chloride evaporation concentrate includes: An evaporation accident pool collects ammonium chloride wastewater generated during the rare earth smelting carbon precipitation process. The circulating pump of the dual circulation switching valve transports ammonium chloride wastewater to the pretreatment sludge tank, where the sludge tank buffers, mixes, and flocculates the liquid. The treated ammonium chloride wastewater is then transported to the plate and frame filter press. Plate and frame filter presses are used for solid-liquid separation of ammonium chloride wastewater. The filtered filtrate is transported to the ammonium chloride raw water tank, and the filter cake is transported off-site for disposal. The ammonium chloride raw water tank receives plate and frame filter filtrate, neutralizes the plate and frame filtrate to form MVR filtrate, and then transports it to the MVR feed device. The MVR feeder delivers the MVR filtrate to the MVR unit, which then uses MVR technology to process the filtrate and produce NH4Cl crystals.
[0010] Preferably, in the pretreatment sludge tank, the dosage of chemicals and the pH value at the reaction endpoint are controlled to cause the suspended solids to flocculate, and the ammonium chloride wastewater is mixed. The mixed ammonium chloride wastewater is then sent to a plate and frame filter press.
[0011] Preferably, when emergency liquid needs to be treated, the circulation pump of the dual circulation switching valve transports the emergency liquid from the evaporation emergency pool to the MVR feed tank, the MVR feed tank transports the emergency liquid to the MVR unit, and the MVR unit uses MVR technology to treat the emergency liquid to generate NH4Cl crystal products.
[0012] Preferably, the plate and frame filtrate is neutralized by adding alkaline solution or quicklime.
[0013] The technical effects of this invention include: 1. This invention relates to a dual-channel circulation system and method for pretreatment and filtration of ammonium chloride evaporation concentrate. Addressing the bottlenecks in the evaporation process of high-concentration, high-impurity ammonium chloride wastewater from rare earth smelting carbon precipitation, such as frequent filter clogging, severe crystallization in filters and pipelines, high energy consumption, and unstable operation, this invention expands the treatment range of MVR technology for ammonium chloride wastewater through a first circulation channel, a second circulation channel, and a dual-circulation switching valve. It can effectively treat ammonium chloride wastewater with complex composition, high solid content, and numerous impurities, effectively reducing the risk of system crystallization and equipment downtime, ensuring the stability of the raw water concentration, guaranteeing smooth production, and reducing energy consumption.
[0014] 2. It provides an efficient and economical solution for the treatment of similar ammonium chloride wastewater and can be widely applied.
[0015] The successful implementation of this technology not only solves the key bottleneck in ammonium chloride wastewater treatment and ensures stable production, but also can be promoted and applied in industries such as rare earth smelting, hydrometallurgy, and chemical engineering. It provides an efficient, reliable, and economically beneficial process optimization path for treating similar high-salt, high-impurity ammonium chloride wastewater.
[0016] 3. Significant economic and environmental benefits.
[0017] Economic benefits: 1) Benefits of energy conservation and emission reduction; The significantly reduced steam and electricity consumption results in direct operating cost savings.
[0018] 2) Reduce maintenance costs; Significantly reduced filter replacement costs and maintenance costs due to equipment blockage and frequent start-stop cycles. 3) Increased production revenue; Increased production due to reduced downtime.
[0019] 4) Savings in labor costs.
[0020] This greatly reduces the labor intensity of cleaning crystals and frequently replacing filters, saving labor costs.
[0021] Practice shows that after optimization, the SS concentration of the filtrate is reduced to <50 mg / L, the clogging frequency of the MVR filter is reduced by 80%, the system crystallization shutdown is reduced by 85%, the overall energy consumption is reduced by 18.7%, and the annual cost is reduced by 965,000 yuan.
[0022] Social benefits: 1) Improved environmental friendliness; Stable and efficient operation is conducive to the treatment of ammonium chloride wastewater to meet standards, resulting in more stable quality of crystalline salts and more reliable resource utilization pathways.
[0023] 2) Enhanced inherent safety: Reduces the number of times personnel need to enter high-risk areas (such as high-temperature environments or environments with harmful gases) to clear blockages, thus lowering safety risks.
[0024] 3) Technical demonstration effect: It provides a reference for process optimization ideas for treating difficult ammonium chloride wastewater in hydrometallurgy and similar industries. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the structural principle of the ammonium chloride evaporation concentrate pretreatment filtration dual-channel circulation system in this invention. Detailed Implementation
[0026] The following description fully illustrates specific embodiments of the present invention to enable those skilled in the art to practice and reproduce it. To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0027] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0028] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0029] like Figure 1 The diagram shown is a schematic diagram of the dual-channel circulation system for the pretreatment and filtration of ammonium chloride evaporation concentrate in this invention.
[0030] The ammonium chloride evaporation concentrate pretreatment filtration dual-channel circulation system includes: an evaporation emergency tank, a dual circulation switching valve, a first circulation channel, and a second circulation channel; The evaporation emergency pool is used to collect high-concentration, high-impurity ammonium chloride wastewater generated during the rare earth smelting carbon precipitation process, as well as a small amount of relatively clean or emergency liquid. Its outlet is connected to the feed port of the dual circulation switching valve through a pipeline. Analysis of the liquid in the evaporation accident tank, which collected high-concentration, high-impurity ammonium chloride wastewater under abnormal system conditions, revealed the following significant characteristics: (1) High solid content and complex impurities; The content of suspended solids (SS), colloids, metal hydroxide precipitates and other mechanical impurities in the feed solution is far higher than that of conventional feed solutions.
[0031] (2) The concentration fluctuates drastically; The accidental discharge resulted in a significantly higher concentration of salt in the feed liquid (mainly NH4Cl) than normal feed.
[0032] (3) High viscosity and easy crystallization: The combined effect of high concentration and impurities leads to an increase in the viscosity of the liquid, making it easier to crystallize in local supersaturated areas during transportation and preheating. (4) Small amounts of emergency fluid that can be cleaned using MVR technology or used in emergency situations.
[0033] An evaporation accident pool can serve as an emergency storage facility for collecting and storing emergency accident wastewater and discharged clean ammonium chloride wastewater, collectively referred to here as accident liquid.
[0034] The dual-circulation switching valve is used to transport ammonium chloride wastewater and emergency liquid to the first circulation channel and the second circulation channel respectively. The dual-circulation switching valve is equipped with an inlet port and two outlet ports. Each of the two outlet ports is equipped with a circulation pump. The two outlet ports are connected to the inlet of the first circulation channel and the second circulation channel respectively through pipelines. The first circulation channel utilizes MVR technology to treat the emergency liquid, including: an evaporation emergency tank, an MVR raw material tank, and an MVR device; The MVR feed tank has its outlet connected to the MVR unit via a pipeline, and its inlet connected to the discharge port of the dual circulation switching valve via a pipeline, for receiving relatively clean or emergency liquids. The MVR unit uses MVR technology to treat emergency fluid and MVR filtrate to produce NH4Cl crystals.
[0035] The MVR feed tank and the inlet of the MVR unit are equipped with filters to remove solid impurities mixed in with the emergency fluid.
[0036] The second circulation channel utilizes MVR technology to treat the liquid feed, including: a pretreatment sludge tank, a plate and frame filter press, an ammonium chloride raw water tank, and an MVR feeding device; The pretreatment sludge tank has its inlet connected to the discharge port of the dual circulation switching valve via a pipeline, and its outlet connected to the inlet of the plate and frame filter press via a pipeline. It receives high-impurity ammonium chloride wastewater from the emergency tank and has buffering, mixing, and flocculation functions, providing stable conditions for plate and frame filter press feeding. The plate and frame filter press is connected to the ammonium chloride raw water tank through a pipeline at its outlet to receive ammonium chloride wastewater. The ammonium chloride wastewater is subjected to solid-liquid separation. The filtered plate and frame filtrate is transported back to the ammonium chloride raw water tank, and the filter cake is transported off-site for disposal. Based on the project's processing capacity, two corrosion-resistant plate and frame filter presses were selected. Each press has a filtration area of 200㎡, 77 plates per unit, a pressing pressure of 14MPa, a feed pressure of 0.8MPa, and a pressing pressure of 1.6MPa. This equipment provides ample filtration area and strong pressing force. The operating cycle, feed pressure, and pressing pressure of the plate and frame filter press are optimized and adjusted in real time according to the properties of the liquid feed. Its advantages are: ① High-efficiency solid-liquid separation; It can effectively retain most of the suspended solids, colloids, large crystal particles and mechanical impurities in the feed liquid, and obtain filtrate with significantly improved clarity.
[0037] ② It has a strong ability to process materials with high solid content and high viscosity, and is especially suitable for the characteristics of liquid in emergency pools.
[0038] ③ The moisture content of the filter cake is controllable.
[0039] After pressing, a filter cake with low moisture content can be obtained, which is convenient for subsequent processing.
[0040] The ammonium chloride raw water tank (carbon precipitation raw water tank) has its outlet connected to the feed device of the MVR system through a pipeline. It is used to receive plate and frame filtrate, neutralize it to form MVR filtrate and transport it to the MVR feed device. The MVR feeder is used to deliver the MVR filtrate to the MVR unit.
[0041] The pretreatment and filtration method for concentrated ammonium chloride evaporation wastewater using a dual-channel circulation system includes the following steps: Step 1: Collect high-concentration, high-impurity ammonium chloride wastewater generated during the rare earth smelting carbon precipitation process in the evaporation accident pond; The first circulation channel is only used when the plate and frame filter press system is under maintenance or when the impurity content of the emergency fluid is extremely low, to directly transport the emergency fluid to the MVR feed tank. Ammonium chloride wastewater from the evaporation emergency tank is preferentially introduced into the pretreatment sludge tank via the second circulation channel for treatment using a plate and frame filter press.
[0042] Step 2: The circulating pump of the dual circulation switching valve transports the ammonium chloride wastewater to the pretreatment sludge tank. The pretreatment sludge tank mixes and flocculates the ammonium chloride wastewater, and then transports the treated liquid to the plate and frame filter press. The pretreatment process precisely controls the dosage (flocculator) and the pH value at the reaction endpoint to flocculate suspended solids in ammonium chloride wastewater.
[0043] When emergency liquid needs to be treated, the circulation pump of the dual circulation switching valve will transport the emergency liquid from the evaporation emergency pool to the MVR feed tank.
[0044] Step 3: The plate and frame filter press performs solid-liquid separation on the ammonium chloride wastewater. The filtered filtrate is transported to the ammonium chloride raw water tank, and the filter cake is transported off-site for disposal. Step 4: The ammonium chloride raw water tank receives the plate and frame filter filtrate, neutralizes it to form MVR filtrate, and then transports it to the MVR feed device; Plate and frame filtrate is usually weakly acidic and can be neutralized by adding alkali or quicklime.
[0045] Step 5: MVR feeder, used to deliver MVR filtrate to the MVR unit; MVR filtrate is the feed liquid that has been normally treated using MVR technology.
[0046] Step 6: The MVR unit receives the emergency fluid and MVR filtrate, and uses MVR technology to treat the emergency fluid and MVR filtrate to generate NH4Cl crystals.
[0047] The first circulation channel is used to treat the emergency liquid. The emergency liquid is pumped from the evaporation emergency tank into the MVR feed tank via a circulation pump, and then sent to the MVR unit for evaporation and crystallization to produce NH4Cl crystals. Using only the first circulation channel presents the following problems: 1) Pre-filtering is missing; If high-impurity liquid feed enters the core MVR equipment (MVR unit, MVR feed tank) directly without effective solid-liquid separation, it will cause frequent filter clogging and blockage of the pipelines of the MVR unit and MVR feed tank.
[0048] 2) The filter clogs frequently; High-impurity liquid from the MVR feed tank is directly transported to the filter of the MVR unit, causing the filter element or screen to be clogged by impurities in a very short time. This requires frequent disassembly, cleaning, or replacement, resulting in a large workload for maintenance and affecting continuous operation.
[0049] 3) Low evaporation efficiency and soaring energy consumption; Impurities accumulate in the evaporator, affecting heat transfer efficiency. Frequent filter clogging and cleaning lead to frequent system start-ups and shutdowns, shortening the effective evaporation time. Processing high-viscosity, high-solids-content liquids requires even more energy.
[0050] 4) The risk of system crystallization blockage increases dramatically; When the high salt concentration of the feed liquid in the evaporation accident tank enters the first circulation channel, it is highly likely to reach supersaturation at points with low flow rates or temperature differences, such as pipe bends, valves, check valves, inter-effect feed pipes, and circulation pump inlets, causing NH4Cl crystal precipitation and severe blockage. This necessitates a forced shutdown for high-pressure water or manual cleaning, which is labor-intensive, carries a high risk of equipment damage, and severely disrupts production balance.
[0051] 5) The concentration of raw water fluctuates greatly.
[0052] Intermittent and high-concentration feed of the evaporation accident tank disrupted the stable feed concentration originally designed for the MVR system, causing fluctuations in evaporation conditions and affecting the quality of the crystallized salt and the overall control stability of the system.
[0053] These problems, when combined, form a key bottleneck that restricts the efficient, stable, and economical operation of the system.
[0054] Optimization of the design and implementation scheme for a dual-channel circulation system using the first and second circulation channels in combination: The single feed channel of the emergency tank is modified by using a dual-circulation switching valve and circulation pump to allow the first and second circulation channels to work together. The first circulation channel handles relatively clean or small amounts of emergency liquid, while the second circulation channel transports the high-concentration, high-impurity liquid from the emergency tank to the pretreatment sludge tank via pipeline. There, it is filtered by a plate and frame filter press and neutralized with raw water, transforming it into MVR feed liquid that can be normally processed by the MVR unit. This achieves a flexible switching / circulation dual-channel system. The dual-channel system improves the filtration effect, effectively reduces the risk of system crystallization and equipment downtime, ensures the stability of the raw water concentration, guarantees smooth production, and reduces energy consumption.
[0055] The terminology used in this invention is descriptive and exemplary, not restrictive. Since this invention can be embodied in many forms without departing from the spirit or essence of the technical solution, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.
Claims
1. A dual-channel circulating system for pretreatment and filtration of ammonium chloride evaporation concentrate, characterized in that, include: An evaporation accident pool is used to collect ammonium chloride wastewater and accident liquid generated during the rare earth smelting carbon precipitation process. Its outlet is connected to the feed port of a dual circulation switching valve via a pipeline. The dual-circulation switching valve is used to transport ammonium chloride wastewater and emergency liquid to the first circulation channel and the second circulation channel respectively. The dual-circulation switching valve is equipped with an inlet port and two outlet ports. Each of the two outlet ports is equipped with a circulation pump. The two outlet ports are connected to the inlet of the first circulation channel and the second circulation channel respectively through pipelines. The first circulation channel uses steam mechanical recompression (MVR) technology to treat emergency fluid and MVR filtrate. The second circulation channel separates the ammonium chloride wastewater into solid and liquid components, and the treated MVR filtrate is then transported to the first circulation channel.
2. The ammonium chloride evaporation concentrate pretreatment filtration dual-channel circulation system as described in claim 1, characterized in that, The first circulation channel includes: an evaporation emergency pool, an MVR feed tank, and an MVR unit; among which... The MVR feed tank has its inlet connected to the discharge port of the dual circulation switching valve via a pipeline, and its outlet connected to the MVR unit via a pipeline for receiving emergency fluid. The MVR unit uses MVR technology to treat emergency fluid and MVR filtrate to produce NH4Cl crystals.
3. The ammonium chloride evaporation concentrate pretreatment filtration dual-channel circulation system as described in claim 2, characterized in that, The second circulation channel includes: a pretreatment sludge tank, a plate and frame filter press, an ammonium chloride raw water tank, and an MVR feeding device, among which... The pretreatment sludge tank has its inlet connected to the discharge port of the dual circulation switching valve via a pipeline, and its outlet connected to the inlet of the plate and frame filter press via a pipeline. It receives ammonium chloride wastewater from the evaporation accident tank and buffers, mixes, and flocculates the ammonium chloride wastewater. The plate and frame filter press has its outlet connected to the ammonium chloride raw water tank via a pipeline to receive ammonium chloride wastewater, perform solid-liquid separation on the ammonium chloride wastewater, transport the filtered plate and frame filtrate to the ammonium chloride raw water tank, and transport the filter cake off-site for disposal. The ammonium chloride raw water tank has its outlet connected to the MVR unit via a pipeline. It is used to receive plate and frame filtrate, neutralize it to form MVR filtrate, and then transport it to the MVR feed unit. The MVR feeder is used to deliver the MVR filtrate to the MVR unit.
4. The dual-channel circulating system for pretreatment and filtration of ammonium chloride evaporation concentrate as described in claim 2, characterized in that, The MVR feed tank and the inlet of the MVR unit are equipped with filters to remove solid impurities mixed in with the emergency fluid.
5. The method for pretreatment and filtration of ammonium chloride concentrate from evaporation as described in claim 1, characterized in that, include: An evaporation accident pool collects ammonium chloride wastewater generated during the rare earth smelting carbon precipitation process. The circulating pump of the dual circulation switching valve transports ammonium chloride wastewater to the pretreatment sludge tank, where the sludge tank buffers, mixes, and flocculates the liquid. The treated ammonium chloride wastewater is then transported to the plate and frame filter press. Plate and frame filter presses are used for solid-liquid separation of ammonium chloride wastewater. The filtered filtrate is transported to the ammonium chloride raw water tank, and the filter cake is transported off-site for disposal. The ammonium chloride raw water tank receives plate and frame filter filtrate, neutralizes the plate and frame filtrate to form MVR filtrate, and then transports it to the MVR feed device. The MVR feeder delivers the MVR filtrate to the MVR unit, which then uses MVR technology to process the filtrate and produce NH4Cl crystals.
6. The dual-channel circulation method for pretreatment and filtration of ammonium chloride evaporation concentrate as described in claim 5, characterized in that, In the pretreatment sludge tank, the dosage of chemicals and the pH value at the reaction endpoint are controlled to flocculate the suspended solids, and the ammonium chloride wastewater is mixed. The mixed ammonium chloride wastewater is then sent to a plate and frame filter press.
7. The dual-channel circulation method for pretreatment and filtration of ammonium chloride evaporation concentrate as described in claim 5, characterized in that, When emergency liquid needs to be treated, the circulation pump of the dual circulation switching valve transports the emergency liquid from the evaporation emergency pool to the MVR feed tank. The MVR feed tank then transports the emergency liquid to the MVR unit. The MVR unit uses MVR technology to treat the emergency liquid and generate NH4Cl crystals.
8. The dual-channel circulation method for pretreatment and filtration of ammonium chloride evaporation concentrate as described in claim 5, characterized in that, Plate and frame filtrate is neutralized by adding alkali solution or quicklime.