Yellow phosphorus water treatment method and treatment system

Abstract

The invention discloses a yellow phosphorus water treatment method and system, and relates to the technical field of water treatment.The treatment method comprises the steps that overflow water of a phosphorus receiving tank is conveyed to multiple stages of vertical flow sedimentation units connected in series, and phosphorus sludge is subjected to step-by-step sedimentation separation under the gravity effect; discharging bottom mud-rich phosphorus generated by the tail end vertical flow sedimentation unit into the rotary drum treatment device, and discharging bottom mud-rich phosphorus generated by the rest vertical flow sedimentation units into the recovery tank; the upper-layer lean mud phosphorus water of each stage of vertical flow sedimentation unit is sequentially conveyed to the next stage of vertical flow sedimentation unit, and the upper-layer clear liquid generated by the tail-end vertical flow sedimentation unit is discharged into a mud phosphorus pool. According to the differentiated resource recovery process, the overflow water of the phosphorus receiving tank is subjected to gradient settling separation in the multi-stage serial vertical flow settling unit, the sludge-rich phosphorus at the bottom of each stage at the front end is recovered in a centralized manner, and the sludge-rich phosphorus at the bottom of the tail end is subjected to deep treatment by the rotary drum; the purposes of improving the phosphorus recovery rate, preventing loss of low-concentration phosphorus sludge and achieving maximum utilization of resources are achieved.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to a method and system for treating yellow phosphorus water. Background Technology

[0002] In the industrial production of yellow phosphorus, the phosphorus-containing furnace gas generated by electric furnace reduction is captured by a condensation system and then undergoes preliminary collection and sedimentation separation of crude phosphorus in a receiving tank. The receiving tank typically consists of a storage tank body equipped with a steam heating device, a liquid level observation window, and a top overflow outlet. Its function is to receive the condensate from the phosphorus vapor from the gas washing process, utilizing gravity sedimentation to achieve preliminary separation of liquid yellow phosphorus from process wastewater. In production practice, the upper overflow water after primary sedimentation in the receiving tank still contains a certain amount of phosphorus mud (i.e., a mixture of yellow phosphorus and solid impurities in suspension). Traditional treatment processes generally guide this overflow water into a sedimentation tank or storage tank, relying on static sedimentation to separate the phosphorus mud from the water. The supernatant after sedimentation is discharged into a phosphorus mud pond, while the phosphorus mud accumulated at the bottom is collected through pipelines to a recycling facility for centralized treatment. The above-mentioned processes typically employ single-stage or a few-stage sedimentation units, with each unit mostly arranged in parallel or simple series. The mud and phosphorus collection method is uniform, and no separate recovery branches are set up for concentration differences, nor are independent deep treatment devices configured at the end of the process, forming a typical "sedimentation separation-centralized recovery" treatment mode.

[0003] However, the aforementioned technologies have limited effectiveness in practical applications, failing to meet the demands for efficient treatment and resource recovery of yellow phosphorus production wastewater. Specifically, the sedimentation and separation efficiency of existing processes suffers from bottlenecks: due to the gradient distribution of phosphorus mud concentration in wastewater, single or limited-stage sedimentation devices cannot adapt to the process requirements of different sedimentation stages, resulting in excessive separation load in high-concentration areas and insufficient capture power in low-concentration areas, fundamentally restricting phosphorus resource recovery rates. Simultaneously, the uniform phosphorus mud collection method ignores the differences in material concentration, leading to fluctuations in resource quality due to the mixed recovery of high-grade and low-grade phosphorus mud, increasing energy consumption and process control difficulty in subsequent purification processes. More significantly, traditional processes lack effective enrichment methods for low-concentration phosphorus mud at the end, leaving fine yellow phosphorus particles that are difficult to settle in the wastewater after sedimentation treatment. This continuous loss of resources not only leads to excessive phosphorus content in the effluent but also poses a potential secondary environmental pollution hazard. Furthermore, the existing systems lack continuous stability, and localized temperature drops during pipeline transportation can easily cause phosphorus mud solidification and blockage. Therefore, a new yellow phosphorus water treatment technology is needed to achieve graded treatment and differentiated resource recovery in order to solve the technical problems of low separation efficiency, unstable recovery quality, and non-compliance with end-of-pipe discharge standards. Summary of the Invention

[0004] The purpose of this invention is to provide a yellow phosphorus water treatment method and system. By performing gradient sedimentation separation of the overflow water from the phosphorus receiving tank in a multi-stage series vertical flow sedimentation unit, and by centrally recovering the phosphorus-rich mud at the bottom of each stage at the front end and deeply treating the phosphorus-rich mud at the bottom of the final stage in a rotary drum, this differentiated resource recovery process solves the technical problems of low phosphorus recovery rate and loss of low-concentration phosphorus mud caused by insufficient sedimentation stages and a unified recovery path in traditional processes.

[0005] The embodiments of the present invention are achieved through the following technical solutions: First, the embodiments of the present invention provide a method for treating yellow phosphorus water, including the following steps: The overflow water from the phosphorus receiving tank is transported to a multi-stage series of vertical flow settling units, so that the mud and phosphorus are separated by settling in stages under the action of gravity. The bottom sludge rich in phosphorus generated by the end vertical flow settling unit is discharged into the rotary drum treatment device, while the bottom sludge rich in phosphorus generated by the remaining vertical flow settling units is discharged into the recycling tank. The upper layer of lean sludge and phosphorus water from each vertical flow settling unit is sequentially transported to the next vertical flow settling unit, and the upper clear liquid generated by the end vertical flow settling unit is discharged into the sludge and phosphorus pond.

[0006] As an optional implementation, the multi-stage vertical flow settling unit includes a first-stage vertical flow channel, a second-stage vertical flow channel, a third-stage vertical flow channel, and a fourth-stage vertical flow channel connected in series along the water flow direction. The bottom of the first-stage, second-stage, and third-stage vertical flow channels, which are rich in sludge and phosphorus, is discharged into a recovery tank, while the bottom of the fourth-stage vertical flow channel, which is rich in sludge and phosphorus, is discharged into a rotary drum treatment device.

[0007] As an optional implementation, the temperature of the first-stage vertical flow channel is maintained at 70~80℃, the temperature of the second-stage vertical flow channel is maintained at 75~85℃, the temperature of the third-stage vertical flow channel is maintained at 75~90℃, and the temperature of the fourth-stage vertical flow channel is maintained at 80~90℃.

[0008] As an alternative implementation, the method also includes discharging the phosphorus-rich mud at the bottom of the phosphorus receiving tank into a refining tank for phosphorus recovery.

[0009] As an optional implementation, the method also includes conveying the overflow water from the refining tank to the refining water separation tank, controlling the temperature of the refining water separation tank at 70~90°C, discharging the bottom mud-phosphorus-rich liquid into the recovery tank, and discharging the upper clear liquid into the mud-phosphorus pond.

[0010] As an alternative implementation, it also includes conveying the overflow water from the refining tank to the front-end vertical flow settling unit.

[0011] Secondly, embodiments of the present invention also provide a yellow phosphorus water treatment system, comprising: The phosphorus receiving tank is used to receive phosphorus-containing wastewater from the yellow phosphorus condensation process and achieve gravity sedimentation separation; the upper overflow outlet of the phosphorus receiving tank is connected to the head end of the multi-stage vertical flow sedimentation unit. The multi-stage vertical flow settling unit includes multiple vertical flow channels connected in series along the water flow direction. The inlet of the first vertical flow channel is connected to the overflow outlet of the upper layer of the phosphorus receiving channel, and the upper clear liquid outlet of the last vertical flow channel is connected to the mud and phosphorus tank. The mud and phosphorus-rich discharge outlet at the bottom of the last vertical flow channel is connected to the rotary drum treatment device for mechanical separation, and the mud and phosphorus-rich discharge outlets at the bottom of the remaining vertical flow channels are connected in parallel to the recovery tank for centralized recovery. Each stage of the vertical flow channel is connected in series with the next stage inlet through the upper clear liquid outlet. The recovery tank is used to collect phosphorus-rich mud from the bottom of the terminal vertical flow tank, providing raw materials for the subsequent centralized phosphorus extraction process; The mud-phosphorus pond is used to temporarily store the supernatant clear liquid after multi-stage sedimentation treatment. The inlet of the mud-phosphorus pond is connected to the supernatant clear liquid outlet of the end vertical flow channel. The rotary drum treatment device is used to mechanically filter or centrifugally separate the low-concentration phosphorus-rich mud discharged from the end vertical flow channel. The inlet of the rotary drum treatment device is connected to the phosphorus-rich mud discharge port at the bottom of the end vertical flow channel. The filtrate outlet flows into the phosphorus mud pool, and the filter cake outlet is connected to the yellow phosphorus recovery system to achieve terminal enrichment and recovery of phosphorus resources.

[0012] As an optional implementation, a refining unit is also included, which is used to receive and directly recover the phosphorus-rich mud from the bottom of the phosphorus receiving tank.

[0013] As an alternative implementation, the refining unit includes a refining tank, the upper overflow outlet of which is connected to the inlet of the first vertical flow channel.

[0014] As an optional implementation, the refining unit includes a refining tank and a refining water separation tank. The inlet of the refining water separation tank is connected to the upper overflow outlet of the refining tank, the upper clear liquid outlet of the refining water separation tank is connected to the mud-phosphorus pond, and the bottom mud-phosphorus discharge outlet of the refining water separation tank is connected to the recovery tank.

[0015] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects: 1. The principle of the yellow phosphorus water treatment method in this embodiment of the invention is based on the difference in sedimentation characteristics of mud phosphorus in a gravitational field and the cascade separation effect of multi-stage series separation: Due to the density difference and particle size distribution of yellow phosphorus and impurities, the mud phosphorus carried in the overflow water of the phosphorus tank has a natural tendency to settle and stratify under gravity. By sequentially introducing the wastewater into multi-stage series vertical flow sedimentation units, the mud phosphorus undergoes an independent sedimentation environment in each unit. The large particles of mud-rich phosphorus with faster sedimentation speed in the previous unit settle to the bottom first and are discharged into the recovery tank. The fine particles that do not settle completely enter the next unit with the upper layer of mud-poor phosphorus water, and continue to settle and separate under the lower solid load and longer effective sedimentation path of the subsequent unit. This progressively decreasing load distribution mechanism avoids the solid flow problems of traditional single-stage sedimentation. The excessive volume of sedimentation water has reduced the overall separation efficiency by preventing interference with sedimentation. The final vertical flow sedimentation unit is located at the lowest mud-phosphorus concentration gradient. Although the concentration of phosphorus-rich mud at its bottom is low, it still contains fine yellow phosphorus particles. Directly incorporating it into the recovery tank would dilute the original high-grade resources. Therefore, it is discharged into the rotary drum treatment device, which utilizes the existing mechanical separation principle to achieve deep capture and enrichment of low-concentration mud-phosphorus, thereby intercepting phosphorus resources that are difficult to recover by conventional gravity sedimentation at the end stage. The upper layer of low-phosphorus mud water in each stage of the vertical flow sedimentation unit is sequentially transported to the next stage, forming a continuous concentration gradient decreasing sequence. This allows each stage of the unit to achieve optimal sedimentation efficiency for mud-phosphorus in a specific concentration range. The upper clear liquid discharged from the final unit has a significantly reduced mud-phosphorus content due to multi-stage separation. After being discharged into the mud-phosphorus pond, it can be directly reused or discharged in compliance with standards. This method decomposes the mud-phosphorus separation process into multiple cascaded sub-processes through a multi-stage series architecture, realizing the gradient distribution of settling load and the step-by-step optimization of separation conditions. It solves the problem of incomplete separation caused by concentrated load in single-stage or few-stage treatment. By organically combining the centralized recovery of high-concentration mud-phosphorus with the deep treatment of low-concentration mud-phosphorus through differentiated emission paths, it avoids the mixing of resource quality and the loss of low-grade resources, improves the overall recovery rate of phosphorus, and reduces the phosphorus content of the end wastewater. At the same time, the continuity of the series process and the specialization of the functions of each unit ensure the long-term stable operation of the system, reducing the volatility and operational complexity of the treatment process.

[0016] 2. The principle of the temperature gradient control scheme in this invention is to match the decreasing mud-phosphorus concentration in each stage of the vertical flow tank by setting differentiated temperatures: The first-stage vertical flow tank receives high-concentration overflow water from the phosphorus receiving tank, with a high mud-phosphorus solid content. Maintaining the temperature at 70-80℃ ensures that the yellow phosphorus is in a molten state and moderately reduces the viscosity of the wastewater, while avoiding excessive temperature to aggravate the agglomeration tendency of yellow phosphorus and impurities; The mud-phosphorus concentration in the second and third-stage vertical flow tanks has been significantly reduced. The temperature is gradually increased to 75-85℃ and 75-90℃, respectively. By further reducing viscosity and enhancing molecular thermal motion, the fine particles with slower settling speeds obtain greater settling driving force, accelerating their enrichment to the bottom; The fourth-stage vertical flow tank treats the low-concentration, low-mud-phosphorus water after the third-stage settling. The residual particle size is the smallest and the settling difficulty is the greatest. Raising the temperature to 80-90℃ can minimize the viscous resistance of the wastewater, so that the yellow phosphorus particles close to the critical settling particle size can still be effectively separated in the final stage, while providing suitable temperature conditions for the subsequent drum treatment device. This temperature gradient setting is not a simple linear increase, but rather the result of optimization based on the mud-phosphorus concentration gradient, sedimentation kinetics, and the physicochemical properties of yellow phosphorus. The lower temperature in the initial stage prevents oxidation or impurity reactions caused by overheating of high-concentration mud-phosphorus, while the higher temperature in the subsequent stage compensates for insufficient separation kinetics in the low-concentration stage, avoiding the shortcomings of traditional single-temperature control that cannot achieve optimal separation effects in both high and low concentration ranges simultaneously. Its technical benefits are reflected in: each stage of the vertical flow channel operates at the optimal temperature matching its mud-phosphorus concentration, maximizing sedimentation efficiency between stages and shortening the total hydraulic residence time; the synergistic optimization of temperature and concentration reduces the risk of yellow phosphorus solidification due to excessively low temperatures and impurity interference due to excessively high temperatures, reducing pipe and equipment blockage rates by over 90%; independent temperature control allows the system to adjust the temperature of each channel in real time according to the production load, reducing energy consumption compared to the traditional unified heating mode, and ensuring that the phosphorus content in the final effluent is consistently below 0.05%, with the overall phosphorus recovery rate increasing to over 85%, achieving overall optimization of separation efficiency, operational stability, and energy economy.

[0017] 3. This invention utilizes a refining tank for phosphorus recovery and limits its temperature settings. The principle is as follows: The phosphorus-rich mud at the bottom of the phosphorus receiving tank is at the forefront of the condensation and phosphorus recovery process, where its mud phosphorus concentration is the highest and its yellow phosphorus purity is the best. This material is directly discharged into the refining tank for priority recovery, avoiding the dilution of resource quality caused by mixing it with low-concentration wastewater in the traditional process. As a dedicated recovery unit for high-grade phosphorus resources, the refining tank still contains a small amount of incompletely separated mud phosphorus in its overflow water. If it is directly discharged into the mud phosphorus pool, it will cause the loss of fine particles. Therefore, the overflow water is introduced into the refining water separation tank for secondary heating and sedimentation. Precise temperature control at 70~90℃ is used to maintain the yellow phosphorus in a molten state and reduce its viscosity, allowing the residual mud phosphorus in the overflow water to be enriched again in an independent sedimentation space. The mud phosphorus-rich mud at the bottom is discharged into the recovery tank and combined with the mud phosphorus in the front vertical flow tank for treatment. The clear liquid at the top is discharged into the mud phosphorus pool as the final effluent. This process design integrates mud phosphorus resources with front-end stripping and recovery and back-end secondary capture according to concentration gradients, forming a resource utilization path of "direct recovery of high concentration - centralized recovery of medium concentration - deep treatment of low concentration". Its technical effects are reflected in the following: high-quality phosphorus resources are directly recovered through the refining tank at the front end, avoiding quality mixing and loss during the multi-stage treatment process at the back end, thus improving the recovery rate; the secondary sedimentation of the overflow water in the refining water separation tank improves the overall capture efficiency of fine mud phosphorus particles, reducing the phosphorus content of the final effluent to below 0.05%; simultaneously, this front-end graded recovery mechanism significantly reduces the treatment load of subsequent multi-stage vertical flow tanks, allowing the four-stage series vertical flow tank system to focus on treating the lower concentration overflow water, shortening the hydraulic retention time, reducing overall treatment energy consumption, and achieving a synergistic improvement in resource quality grading, maximizing recovery rate, and optimizing system load.

[0018] 4. In this embodiment of the invention, the principle of conveying the overflow water from the refining tank to the front-end vertical flow settling unit is as follows: The phosphorus-rich mud at the bottom of the phosphorus receiving tank has the highest concentration and best quality, and is directly discharged into the refining tank for independent recovery, avoiding resource dilution caused by mixing with low-concentration wastewater. Although the overflow water from the refining tank has undergone preliminary separation, it still contains a certain amount of suspended phosphorus mud. Traditional processes require a separate refining water separation tank for secondary treatment. In this embodiment, the overflow water is directly conveyed to the front-end vertical flow settling unit, where it mixes with the overflow water from the phosphorus receiving tank and enters the primary vertical flow tank. The gradient settling capacity of the vertical flow tank series system is used to uniformly treat the mixed wastewater. The core of this design is to merge the originally parallel refining water separation branches into the main settling system. Through the redundancy of the settling space in the front-end vertical flow tank and the load distribution capacity of the multi-stage series system, the treatment requirements of the refining tank overflow water are absorbed, eliminating the need for a separate refining water separation tank and its supporting equipment, thus achieving process streamlining, integration, and simplification. Its technical advantages are reflected in the following aspects: a reduction in the number of system equipment, lower footprint, and lower initial investment; the overflow from the refining tank is directly incorporated into the front-end vertical flow tank, allowing the phosphorus mud contained therein to undergo the same gradient separation process as the main process in the four-stage series system, improving the total phosphorus recovery rate compared to independent treatment methods and avoiding the loss of fine particles due to insufficient settling stages during individual treatment; after the mixed wastewater enters the first-stage vertical flow tank, the low concentration of the refining tank overflow dilutes the initial concentration of the phosphorus-receiving tank overflow, reducing the single-stage settling load and making the settling distribution of phosphorus mud particles more uniform in the first to fourth-stage vertical flow tanks, thus improving the settling efficiency of each stage of the tank; at the same time, the unified control system can cover the transportation and treatment of the refining tank overflow, reducing the complexity of operation nodes and automated interlocks, lowering the frequency of manual intervention, enhancing the stability of continuous system operation, and achieving multi-objective optimization of resource quality grading, process structure simplification, and improved operational reliability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the yellow phosphorus water treatment process provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the yellow phosphorus water treatment process provided in Embodiment 2 of the present invention. Detailed Implementation

[0021] 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 embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this invention, it should be noted that the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Example

[0025] Example 1: This embodiment of the invention provides a method for treating yellow phosphorus water, referring to... Figure 1 As shown, it includes the following: The overflow water from the phosphorus receiving tank is pumped through a transfer pump at a rate of 20-50 m³ / h. 3 A multi-stage vertical flow settling unit is pumped in at a flow rate of / h. This unit consists of four vertical flow channels connected in series along the water flow direction: a primary vertical flow channel, a secondary vertical flow channel, a tertiary vertical flow channel, and a quaternary vertical flow channel. Each channel has a vertical cylindrical conical bottom structure, with an inner liner made of 304 stainless steel and an outer carbon steel layer. The middle layer is filled with a high-temperature resistant rock wool insulation layer with a thermal conductivity ≤0.04W / (m·K), and the effective volume is ≥50m³. 3 The temperature of the first-stage vertical flow tank is maintained at 70-80℃, the second-stage at 75-85℃, the third-stage at 75-90℃, and the fourth-stage at 80-90℃ using independent temperature control devices. This allows the mud and phosphorus to settle and separate gradually under gravity. When the mud-rich phosphorus liquid level at the bottom of the first and third-stage vertical flow tanks reaches 1 / 5 of the tank height, it is automatically discharged into the recovery tank. The mud-rich phosphorus liquid at the bottom of the fourth-stage vertical flow tank is discharged into the rotary drum treatment device. The upper layer of lean mud and phosphorus water from each stage is sequentially transported to the next stage of the vertical flow tank. The clear liquid at the top of the fourth-stage vertical flow tank is finally discharged into the mud and phosphorus pool. The system also includes pumping the overflow water from the refining tank at a rate of 20-50 m³ / h. 3A flow rate of / h is pumped into the refined water separation tank, and the temperature of the refined water separation tank is controlled at 70~85℃. The bottom layer of mud-phosphorus-rich water is discharged into the recovery tank, and the upper clear liquid is discharged into the mud-phosphorus pool. All connecting pipes are made of 304 stainless steel with a diameter of Φ50~200mm. The outer side is wrapped with a steam heating layer and a 50~80mm thick rock wool insulation layer. The valves are jacketed insulated pneumatic ball valves. The PLC control system automatically adjusts the steam supply of the steam coil and heating pipes based on the ±1℃ accuracy feedback of the temperature sensor and the 0~5m range monitoring of the liquid level gauge. This achieves automatic material conveying, automatic temperature adjustment, and continuous automated operation, preventing mud-phosphorus from solidifying and clogging below 44℃. It ensures that the system temperature is stable at 70~90℃, the yellow phosphorus recovery rate is ≥85%, and the phosphorus content of the final effluent is ≤0.05%.

[0026] The principle of this method is as follows: Utilizing the physical property that yellow phosphorus remains in a molten liquid state at 70-90℃ and its viscosity decreases with increasing temperature, a four-stage vertical flow trough is designed with a progressively increasing temperature gradient. This ensures that each stage of the trough is within the optimal viscosity range matching the phosphorus concentration of that stage, preventing phosphorus oxidation and agglomeration due to overheating in high-concentration areas, while simultaneously enhancing the settling driving force of fine particles in low-concentration areas. The vertical cylindrical conical bottom structure of each stage of the vertical flow trough reduces the cross-sectional area and increases the solid-liquid concentration gradient through the conical bottom, which, combined with gravity settling, achieves the layer-by-layer enrichment and separation of phosphorus in the mud. The first three stages of bottom-rich phosphorus mud are recycled in parallel to avoid dilution of high-grade resources at the end. The final stage rotary drum deep treatment device captures fine particles that are difficult to recover by gravity sedimentation through a mechanical forced separation mechanism, forming a synergistic recovery system of "gravity sedimentation + mechanical separation". The PLC control system uses real-time signal feedback from temperature sensors and level gauges to control the delivery pump and jacketed insulated pneumatic ball valves, realizing automatic sludge discharge based on the lower limit of the liquid level and automatic heating based on temperature deviation adjustment, ensuring that the whole process operates under constant temperature, continuous and automated conditions.

[0027] The technical advantages of this method are as follows: the yellow phosphorus recovery rate is stably maintained at over 85%, the phosphorus content in the final effluent is reduced to below 0.05%, and resource loss is reduced; the whole system's heat preservation and heat tracing design reduces the risk of yellow phosphorus solidification, and the continuous operation cycle is extended to over 30 days without clogging; automated control reduces the intensity of manual operation, reduces the number of operators, significantly reduces safety risks, and increases the processing capacity per unit area, making it suitable for large-scale industrial continuous production; and the differentiated recovery path improves the purity of high-concentration mud phosphorus.

[0028] Example 2: This embodiment of the invention provides a method for treating yellow phosphorus water, referring to... Figure 2 As shown, it includes the following: The overflow water from the phosphorus receiving tank is pumped through a transfer pump at a rate of 20-50 m³ / h. 3A multi-stage vertical flow settling unit is pumped in at a flow rate of / h. This unit consists of four vertical flow channels connected in series along the water flow direction: a primary vertical flow channel, a secondary vertical flow channel, a tertiary vertical flow channel, and a quaternary vertical flow channel. Each channel has a vertical cylindrical conical bottom structure, with an inner liner made of 304 stainless steel and an outer carbon steel layer. The middle layer is filled with a high-temperature resistant rock wool insulation layer with a thermal conductivity ≤0.04W / (m·K), and the effective volume is ≥50m³. 3 The temperature of the first-stage vertical flow tank is maintained at 70-80℃, the second-stage at 75-85℃, the third-stage at 75-90℃, and the fourth-stage at 80-90℃ using independent temperature control devices. This allows the mud and phosphorus to settle and separate gradually under gravity. When the mud-rich phosphorus liquid level at the bottom of the first and third-stage vertical flow tanks reaches 1 / 5 of the tank height, it is automatically discharged into the recovery tank. The mud-rich phosphorus liquid at the bottom of the fourth-stage vertical flow tank is discharged into the rotary drum treatment device. The upper layer of lean mud and phosphorus water from each stage is sequentially transported to the next stage of the vertical flow tank. The clear liquid at the top of the fourth-stage vertical flow tank is finally discharged into the mud and phosphorus pool. The system also includes pumping the overflow water from the refining tank at a rate of 20-50 m³ / h. 3 The flow rate is conveyed at a rate of / h to the front-end vertical flow settling unit, i.e., the first-stage vertical flow trough, where it mixes with the overflow water from the phosphorus receiving tank and undergoes gradient settling separation. All connecting pipes are made of 304 stainless steel with a diameter of Φ50~200mm, and are wrapped with a steam heating layer and a 50~0mm thick rock wool insulation layer. The valves are jacketed insulated pneumatic ball valves. The PLC control system automatically adjusts the steam supply of the steam coil and heating pipes based on the ±1℃ accuracy feedback from the temperature sensor and the 0~5m range monitoring of the liquid level gauge. This achieves automatic material conveying, automatic temperature adjustment, and continuous automated operation, preventing mud phosphorus from solidifying and clogging below 44℃, ensuring that the system temperature is stable at 70~90℃, the yellow phosphorus recovery rate is ≥85%, and the phosphorus content in the final effluent is ≤0.05%.

[0029] The principle of this method is as follows: Utilizing the physical property that yellow phosphorus remains in a molten liquid state at 70-90℃ and its viscosity decreases with increasing temperature, a temperature gradient design with four-stage vertical flow tanks is used to ensure that each stage of the tank is within the optimal viscosity range matching the phosphorus concentration of that stage. The overflow from the refining tank is directly incorporated into the first-stage vertical flow tank. Taking advantage of the settling redundancy space of this tank and the load distribution capacity of the four-stage series system, the low-concentration phosphorus wastewater generated in the refining process is treated in a unified gradient, eliminating the need for a separate refining water separation tank. This allows the refining overflow and the phosphorus-receiving tank overflow to undergo a combined four-stage treatment process. The first three stages of sedimentation separation ensure that residual fine yellow phosphorus particles in the refined overflow water are fully captured in the first three vertical flow channels. The final stage rotary drum deep treatment device further enhances the forced separation of low-concentration mud phosphorus, forming a short-process collaborative recycling system of "front-end mixing input, gradient sedimentation separation, and end-end mechanical enrichment". The PLC control system uses real-time signal feedback from temperature sensors and level gauges to control the delivery pump and jacketed insulated pneumatic ball valves, realizing automatic sludge discharge triggered by the lower limit of the liquid level and automatic heating based on temperature deviation adjustment, ensuring that the entire process operates under constant temperature, continuous and automated conditions.

[0030] The technical advantages of this method are as follows: the yellow phosphorus recovery rate is stably maintained at over 85%, the phosphorus content in the final effluent is reduced to below 0.05%, and resource loss is reduced; the whole system's heat preservation and heat tracing design reduces the risk of yellow phosphorus solidification, and the continuous operation cycle is extended to over 30 days without clogging; automated control reduces the intensity of manual operation, reduces the number of operators, significantly reduces safety risks, and increases the processing capacity per unit area, making it suitable for large-scale industrial continuous production; and the differentiated recovery path improves the purity of high-concentration mud phosphorus.

[0031] It should be noted that in Embodiments 1 and 2 of the present invention, the independent temperature control components provided in the embodiments of the present invention are implemented using existing technologies, and there are no limitations here, as long as the purpose of separate temperature control can be achieved. For example, each unit is equipped with a steam coil, a temperature sensor, an automatic regulating valve, and a tank insulation layer to form a closed-loop control system. Each stage of vertical flow sedimentation unit and refined water separation tank is independently configured, and the temperature parameters can be set separately according to the mud-phosphorus concentration and sedimentation stage requirements of that stage. The steam coil is installed on the inner wall of the tank, and the temperature sensor monitors the liquid phase temperature in real time and feeds it back to the automatic regulating valve. By adjusting the steam flow rate, the temperature in the tank is stabilized within ±2℃ of the set value. The insulation layer reduces heat loss and ensures temperature control accuracy and energy efficiency. Meanwhile, the number of stages in the multi-stage vertical flow settling unit is not limited. It can be flexibly set to three, five or more stages according to the mud-phosphorus concentration, treatment volume and effluent index requirements of the overflow water from the phosphorus receiving tank. The front stage is mainly used to treat high-concentration mud-phosphorus and centrally recover it to the recovery tank, while the end stage is specially used to treat low-concentration lean mud-phosphorus and is connected to the rotary drum treatment device. The increase or decrease of the number of stages does not affect the core process principle of "gradient settling + differentiated recovery". Other embodiments of the present invention can adapt to the needs of industrial applications of different scales simply by adjusting the series length and temperature gradient distribution.

[0032] Example 3: This embodiment of the invention provides a yellow phosphorus wastewater treatment system, including a phosphorus receiving tank for receiving phosphorus-containing wastewater from the yellow phosphorus condensation process and achieving gravity sedimentation. Its bottom mud-rich phosphorus discharge outlet is connected to a refining tank, and its upper overflow outlet is connected to the head end of a multi-stage vertical flow sedimentation unit. The refining tank, as a front-end quality grading and recovery unit, is used to directly recover high-quality phosphorus resources from the lower layer. Its upper overflow outlet is connected to the inlet of a primary vertical flow trough, introducing secondary low-concentration wastewater into the main sedimentation system. The multi-stage vertical flow sedimentation unit consists of a primary, secondary, tertiary, and quaternary vertical flow trough connected in series along the water flow direction. Each tank has a vertical cylindrical conical bottom structure, with an inner liner made of 304 stainless steel, an outer carbon steel layer, and a high-temperature resistant rock wool insulation layer with a thermal conductivity ≤0.04W / (m·K) in between, and an effective volume ≥50m³. 3 The bottom mud-phosphorus-rich discharge outlets of the first to third stage vertical flow channels are connected in parallel to the recovery tank. The bottom mud-phosphorus-rich discharge outlet of the fourth stage vertical flow channel is connected to the rotary drum treatment device. The upper clear liquid outlet of the fourth stage vertical flow channel is connected to the mud-phosphorus tank. The inlet of the first stage vertical flow channel receives the overflow water from the refining tank. Each stage is connected in series with the next stage inlet through the upper clear liquid outlet. The recovery tank is made of 304 stainless steel and has a capacity of ≥30m³. 3The system is equipped with steam tracing to maintain a temperature of 70-80℃, with its inlet connected in parallel to the bottom of the first to third stage vertical flow channels and the bottom of the refining tank for high-concentration phosphorus mud discharge. A phosphorus mud tank is used to temporarily store the final clear liquid, with its inlet connected to the upper clear liquid outlet of the fourth stage vertical flow channel. A rotary drum treatment device is used for deep separation of low-concentration high-concentration phosphorus mud, with its inlet independently connected to the bottom of the fourth stage vertical flow channel for high-concentration phosphorus mud discharge. All connecting pipes are made of 304 stainless steel, with a diameter of Φ50-200mm, and are wrapped with a steam tracing layer and a 50-80mm thick rock wool insulation layer. Valves are jacketed insulated pneumatic ball valves. A PLC control system automatically adjusts the steam supply to the steam coils and tracing pipes based on temperature sensor feedback (±1℃ accuracy) and level gauge monitoring (0-5m range), achieving automatic material conveying, automatic temperature regulation, and continuous automated operation. The system has a processing capacity of 20-50m³. 3 / h, temperature is stably controlled at 70~90℃, yellow phosphorus recovery rate ≥85%, and phosphorus content in the final effluent ≤0.05%.

[0033] In this embodiment of the invention, the high-concentration rich sludge phosphorus at the bottom of the receiving tank is directly discharged into the refining tank to achieve front-end quality grading and recovery. The overflow water from the upper layer of the refining tank is introduced into the first-stage vertical flow tank, and after mixing with the overflow water from the receiving tank, they enter the four-stage series gradient sedimentation system. Differentiated temperature control is achieved by using independent temperature control devices at each stage, with the first stage at 70~80℃, the second stage at 75~85℃, the third stage at 75~90℃, and the fourth stage at 80~90℃. This allows the sludge phosphorus to be enriched and separated step by step under the action of gravity. The rich sludge phosphorus at the bottom of the first three stages is collected in parallel, and the low-concentration rich sludge phosphorus at the bottom of the last stage is deeply recovered through mechanical separation by a rotary drum. The clear liquid at the top flows into the sludge phosphorus pool, forming a short-process collaborative treatment system of "front-end refining and stripping + mid-stage gradient sedimentation + end-stage mechanical enrichment". The PLC system ensures constant temperature and continuous operation throughout the entire process through real-time monitoring and interlocking control.

[0034] Example 4: This embodiment of the invention provides a yellow phosphorus water treatment system, including a phosphorus receiving tank for receiving phosphorus-containing wastewater from the yellow phosphorus condensation process and achieving gravity sedimentation. Its bottom mud-rich phosphorus discharge outlet is connected to a refining tank, and its upper overflow outlet is connected to the head of a multi-stage vertical flow sedimentation unit. The refining tank is used to directly recover high-quality phosphorus resources from the lower layer. The refining water separation tank is used to treat the overflow water from the refining tank; its inlet is connected to the upper overflow outlet of the refining tank, its upper clear liquid outlet is connected to a mud-phosphorus tank, and its bottom mud-rich phosphorus discharge outlet is connected to a recovery tank. The multi-stage vertical flow sedimentation unit consists of a first-stage, second-stage, third-stage, and fourth-stage vertical flow tank connected in series along the water flow direction. Each tank has a vertical cylindrical conical bottom structure, with an inner liner made of 304 stainless steel, an outer carbon steel layer, and a high-temperature resistant rock wool insulation layer with a thermal conductivity ≤0.04W / (m·K) in between, and an effective volume ≥50m³. 3The bottom mud-rich phosphorus discharge outlets of the first to third stage vertical flow channels are connected in parallel to the recovery tank. The bottom mud-rich phosphorus discharge outlet of the fourth stage vertical flow channel is connected to the rotary drum treatment device. The upper clear liquid outlet of the fourth stage vertical flow channel is connected to the mud-phosphorus tank. The inlet of the first stage vertical flow channel receives the overflow water from the phosphorus tank. Each stage is connected in series with the next stage inlet through the upper clear liquid outlet. The recovery tank is made of 304 stainless steel and has a capacity of ≥30m³. 3 The system is equipped with steam tracing to maintain a temperature of 70-80℃. The inlet is connected in parallel to the bottom mud-phosphorus discharge outlet of the first to third stage vertical flow channels and the refined water separation tank. A mud-phosphorus tank is used to temporarily store the final clarified liquid; its inlet is connected to the upper clarified liquid outlet of the fourth stage vertical flow channel and the upper clarified liquid outlet of the refined water separation tank. A rotary drum treatment device is used for deep separation of low-concentration mud-phosphorus, with its inlet independently connected to the bottom mud-phosphorus discharge outlet of the fourth stage vertical flow channel. All connecting pipes are made of 304 stainless steel, with a diameter of Φ50-200mm, and are wrapped with a steam tracing layer and a 50-80mm thick rock wool insulation layer. Valves are jacketed insulated pneumatic ball valves. A PLC control system automatically adjusts the steam supply of the steam coil and tracing pipes based on temperature sensor feedback (±1℃ accuracy) and level gauge monitoring (0-5m range), achieving automatic material conveying, automatic temperature regulation, and continuous automated operation. The system has a processing capacity of 20-50m³. 3 / h, temperature is stably controlled at 70~90℃, yellow phosphorus recovery rate ≥85%, and phosphorus content in the final effluent ≤0.05%.

[0035] In this embodiment of the invention, the high-concentration rich sludge phosphorus at the bottom of the receiving tank is directly discharged into the refining tank for front-end quality grading and recovery. The overflow water from the upper layer of the refining tank is introduced into the refining water separation tank for secondary heating and sedimentation, with the temperature controlled at 70~85℃. The bottom rich sludge phosphorus is discharged into the recovery tank, and the upper clear liquid is discharged into the sludge phosphorus pool. The overflow water from the receiving tank independently enters a multi-stage vertical flow sedimentation unit, and differentiated temperature control is achieved by using independent temperature control devices at each stage. The first stage is 70~80℃, the second stage is 75~85℃, the third stage is 75~90℃, and the fourth stage is 80~90℃, so that the sludge phosphorus is enriched and separated step by step under the action of gravity. The bottom rich sludge phosphorus in the first three stages is collected in parallel, and the low-concentration rich sludge phosphorus at the bottom of the last stage is deeply recovered through mechanical separation by a rotary drum. The upper clear liquid flows into the sludge phosphorus pool, forming a parallel processing system of "front-end refining and stripping + middle-stage independent sedimentation + back-end multi-stage gradient separation". The PLC system ensures constant temperature and continuous operation of the entire process through real-time monitoring and interlocking control.

[0036] Overall, the yellow phosphorus water treatment system provided by this invention achieves efficient, stable, and automated operation: Through a four-stage gradient separation architecture with multi-stage vertical flow settling units, it performs refined recovery of phosphorus sludge from the overflow water of the phosphorus receiving tank, reducing the total phosphorus recovery rate by more than 40% compared to the old system, and lowering the phosphorus content in the final effluent to extremely low levels, thus reducing pollution emissions at the source; the entire system adopts independent temperature control components and steam heating insulation design, maintaining the temperature of each vertical flow tank, refined water separation tank, pipeline, and valve stably at 70~90℃, effectively preventing phosphorus sludge from solidifying and clogging below 44℃, ensuring continuous operation without accidents throughout the year; the PLC control system, through the linkage of level gauges, temperature sensors, and jacketed insulated pneumatic ball valves, realizes automatic material conveying, automatic sludge discharge, and automatic temperature adjustment, reducing the intensity of manual operation and safety hazards; the vertical cylindrical conical bottom structure of the vertical flow tanks is compactly arranged, with a single tank capacity ≥50m³. 3 With 20~50m 3 With a processing capacity of / h, it occupies a small area and is suitable for large-scale industrial continuous production, thus improving overall economic benefits.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and descriptions of well-known components, processing techniques, and processes have been omitted to avoid unnecessarily limiting the invention.

Claims

1. A method for treating yellow phosphorus water, characterized in that, Includes the following steps: The overflow water from the phosphorus receiving tank is transported to a multi-stage series of vertical flow settling units, so that the mud and phosphorus are separated by settling in stages under the action of gravity. The bottom sludge rich in phosphorus generated by the end vertical flow settling unit is discharged into the rotary drum treatment device, while the bottom sludge rich in phosphorus generated by the remaining vertical flow settling units is discharged into the recycling tank. The upper layer of lean sludge and phosphorus water from each vertical flow settling unit is sequentially transported to the next vertical flow settling unit, and the upper clear liquid generated by the end vertical flow settling unit is discharged into the sludge and phosphorus pond.

2. The method for treating yellow phosphorus water according to claim 1, characterized in that, The multi-stage vertical flow settling unit includes a first-stage vertical flow channel, a second-stage vertical flow channel, a third-stage vertical flow channel, and a fourth-stage vertical flow channel connected in series along the water flow direction. The bottom of the first-stage, second-stage, and third-stage vertical flow channels, which are rich in sludge and phosphorus, is discharged into a recovery tank, while the bottom of the fourth-stage vertical flow channel, which is rich in sludge and phosphorus, is discharged into a rotary drum treatment device.

3. The method for treating yellow phosphorus water according to claim 2, characterized in that, The temperature of the first-stage vertical flow channel is maintained at 70~80℃, the temperature of the second-stage vertical flow channel is maintained at 75~85℃, the temperature of the third-stage vertical flow channel is maintained at 75~90℃, and the temperature of the fourth-stage vertical flow channel is maintained at 80~90℃.

4. The method for treating yellow phosphorus water according to claim 1, characterized in that, It also includes discharging the phosphorus-rich mud from the bottom of the phosphorus receiving tank into a refining tank, which is used for phosphorus recovery.

5. The yellow phosphorus water treatment method according to claim 4, characterized in that, It also includes transporting the overflow water from the refining tank to the refining water separation tank, controlling the temperature of the refining water separation tank at 70~90℃, discharging the bottom mud-phosphorus-rich liquid into the recovery tank, and discharging the upper clear liquid into the mud-phosphorus pond.

6. The yellow phosphorus water treatment method according to claim 4, characterized in that, It also includes transporting the overflow water from the refining tank to the front-end vertical flow settling unit.

7. A yellow phosphorus water treatment system, characterized in that, include: The phosphorus receiving tank is used to receive phosphorus-containing wastewater from the yellow phosphorus condensation process and achieve gravity sedimentation separation. The upper overflow outlet of the phosphorus receiving tank is connected to the first end of the multi-stage vertical flow settling unit; The multi-stage vertical flow settling unit includes multiple vertical flow channels connected in series along the water flow direction. The inlet of the first vertical flow channel is connected to the overflow outlet of the upper layer of the phosphorus receiving channel, and the upper clear liquid outlet of the last vertical flow channel is connected to the mud and phosphorus tank. The mud and phosphorus-rich discharge outlet at the bottom of the last vertical flow channel is connected to the rotary drum treatment device for mechanical separation, and the mud and phosphorus-rich discharge outlets at the bottom of the remaining vertical flow channels are connected in parallel to the recovery tank for centralized recovery. Each stage of the vertical flow channel is connected in series with the next stage inlet through the upper clear liquid outlet. The recovery tank is used to collect phosphorus-rich mud from the bottom of the terminal vertical flow tank, providing raw materials for the subsequent centralized phosphorus extraction process; The mud-phosphorus pond is used to temporarily store the supernatant clear liquid after multi-stage sedimentation treatment. The inlet of the mud-phosphorus pond is connected to the supernatant clear liquid outlet of the end vertical flow channel. The rotary drum treatment device is used to mechanically filter or centrifugally separate the low-concentration phosphorus-rich mud discharged from the end vertical flow channel. The inlet of the rotary drum treatment device is connected to the phosphorus-rich mud discharge port at the bottom of the end vertical flow channel. The filtrate outlet flows into the phosphorus mud pool, and the filter cake outlet is connected to the yellow phosphorus recovery system to achieve terminal enrichment and recovery of phosphorus resources.

8. A yellow phosphorus water treatment system according to claim 6, characterized in that, It also includes a refining unit, which is used to receive and directly recover phosphorus-rich mud from the bottom of the phosphorus receiving tank.

9. A yellow phosphorus water treatment system according to claim 8, characterized in that, The refining unit includes a refining tank, and the upper overflow outlet of the refining tank is connected to the inlet of the first vertical flow channel.

10. A yellow phosphorus water treatment system according to claim 8, characterized in that, The refining unit includes a refining tank and a refining water separation tank. The inlet of the refining water separation tank is connected to the upper overflow outlet of the refining tank. The upper clear liquid outlet of the refining water separation tank is connected to the mud-phosphorus pond. The bottom mud-phosphorus discharge outlet of the refining water separation tank is connected to the recovery tank.

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