A continuous dehydrating and phosphorus extracting equipment and process for sludge containing phosphorus

Abstract

The present application relates to a kind of mud phosphorus continuous dehydration phosphorus extraction equipment and process, equipment includes feed system, vacuum heating evaporation system, residue discharge system, gas recovery processing system and vacuum system, feed system is realized mud phosphorus continuous shunt delivery by mud phosphorus feed tank and multiple mud phosphorus feed pump;Vacuum heating evaporation system uses multilayer belt, heat-conducting oil heating plate with movable mud phosphorus distributor is equipped in the lower portion of belt, realizes uniform distribution and subsection accurate heating;Residue discharge system is continuously discharged mud phosphorus residue by receiving tank and screw conveyor;Gas recovery processing system recovers yellow phosphorus and purifies tail gas by spray tower and caustic wash, vacuum system provides stable negative pressure environment for the whole evaporation process.Based on the process of the equipment, the whole process of mud phosphorus from feeding, dehydration, phosphorus evaporation, residue discharge to tail gas treatment is realized continuous operation, with the advantages of continuous high efficiency, accurate temperature control, high yellow phosphorus recovery rate, low energy consumption, safety and environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of phosphorus chemical technology, specifically relating to a continuous dehydration and phosphorus extraction equipment and process for mud phosphorus. Background Technology

[0002] Sludge phosphorus is an amorphous, latex-like mixture produced during the production of yellow phosphorus, mainly containing yellow phosphorus, moisture, silt, and silicate impurities. Direct discharge not only results in a severe waste of yellow phosphorus resources but also causes persistent pollution to soil, water, and the atmosphere, threatening ecological security and human health. Therefore, developing efficient and clean sludge phosphorus dehydration and phosphorus extraction technologies is a crucial step for the phosphorus chemical industry to achieve resource recycling and clean production.

[0003] Currently, the mainstream process for treating mud phosphorus is the rotary distillation process. This process involves loading mud phosphorus into a rotating distillation vessel, using yellow phosphorus tail gas as a heat source for external heating, and evaporating moisture and yellow phosphorus sequentially under vacuum conditions. The yellow phosphorus is then recovered after spray cooling. However, this process has significant drawbacks: First, it employs intermittent operation, with a single batch processing cycle lasting 6-8 hours, requiring cooling and manual slag removal, resulting in low production efficiency and high labor intensity. Second, the rotary distillation vessel uses direct external heating with yellow phosphorus tail gas, and each mud phosphorus treatment involves heating and cooling processes, leading to severe thermal deformation and corrosion, and a short service life, typically only 3-4 months. Third, each heating and cooling cycle results in significant energy loss and high processing costs. Fourth, the tail gas treatment system is simple and prone to secondary pollution.

[0004] To address the aforementioned issues, existing patents (such as CN99126936.5) have proposed a medium-temperature vacuum phosphorus extraction process. However, this method remains an intermittent operation with limited temperature control precision, failing to fundamentally improve the yellow phosphorus recovery rate, and resulting in incomplete exhaust gas purification and insufficient environmental friendliness. Furthermore, existing technologies generally suffer from common problems such as uneven distribution of phosphorus mud on the heating surface and the inability to precisely control the heating temperature in segments along the material's direction of travel. Additionally, due to the high degree of equipment openness, there are safety risks such as spontaneous combustion and leakage of yellow phosphorus, making it difficult to meet the requirements of large-scale, continuous, safe, and clean industrial production.

[0005] Therefore, there is an urgent need to develop a new type of mud phosphorus dewatering and phosphorus extraction equipment and process that can achieve continuous feeding, uniform material distribution, segmented precise temperature control, efficient phosphorus stripping, and compliant exhaust gas emissions, in order to overcome the shortcomings of existing technologies and improve resource recovery efficiency and environmental protection level. Summary of the Invention

[0006] The purpose of this invention is to provide a continuous dehydration and phosphorus extraction equipment for mud phosphorus, which achieves continuous feeding, uniform distribution, precise segmented heating, efficient phosphorus stripping, and compliant exhaust gas emission, thereby improving the clean and efficient recovery of yellow phosphorus and achieving the dual goals of reducing energy consumption, ensuring operational safety, and balancing resource recovery and environmental governance.

[0007] The technical solution adopted by the present invention to solve the above problems is: a continuous dehydration and phosphorus extraction equipment for mud phosphorus, comprising a feeding system, a vacuum heating and evaporation system, a residue discharge system, a gas recovery and treatment system, and a vacuum system; The feeding system includes a mud-phosphorus feed tank, a conveying pump, and multiple mud-phosphorus feed pumps. The conveying pumps are respectively connected to an external mud-phosphorus storage device and the mud-phosphorus feed tank. The bottom of the mud-phosphorus feed tank is provided with a main pipe, and the outlet end of the main pipe branches to the feed ends of multiple mud-phosphorus feed pumps.

[0008] The vacuum heating evaporation system includes a vacuum-sealed cavity, multiple mud-phosphorus distributors, multiple layers of continuous horizontal running belts, multiple rollers, and multiple layers of heat-conducting oil heating plates. The vacuum-sealed cavity is a closed structure with a feed port on one side connected to the discharge end of the mud-phosphorus feed pump and a residue discharge port on the other side. Multiple mud-phosphorus distributors are installed inside the vacuum-sealed cavity and close to the feed port. Each mud-phosphorus distributor is connected to the discharge end of each mud-phosphorus feed pump. The multiple belts are arranged at intervals in the vertical direction. Each belt includes an upper horizontal section and a lower return section. The two ends of each belt are respectively fitted onto the corresponding rollers, which are connected to the drive motor. The heat-conducting oil heating plates are fixed on the upper horizontal running section of each belt. The heat-conducting oil heating plates are divided into multiple independent heating sections along the belt running direction, and each heating section is equipped with an independent temperature control device.

[0009] The residue discharge system includes a receiving tank and a screw conveyor. The receiving tank is located below the residue outlet of the vacuum-sealed cavity, and the screw conveyor is connected to the receiving tank.

[0010] The gas recovery and treatment system includes a yellow phosphorus cooling spray tower and an alkaline scrubbing tower. The air inlet of the yellow phosphorus cooling spray tower is connected to the vacuum port at the top of the vacuum sealing chamber, and the air inlet of the alkaline scrubbing tower is connected to the tail gas outlet of the yellow phosphorus cooling spray tower. The vacuum port at the top of the vacuum-sealed cavity is connected in sequence to the yellow phosphorus cooling spray tower, the alkali washing tower, and the vacuum pump via vacuum pipelines.

[0011] Preferably, one end of the mud and phosphorus distributor is fixed to one side of the belt feed end, and the other end is driven by a servo motor to swing back and forth along the belt running direction. The bottom of the mud and phosphorus distributor discharge end is provided with multiple spray holes. With the left and right swing of the mud and phosphorus distributor, the mud and phosphorus are evenly distributed on the belt, avoiding local accumulation that leads to uneven heating.

[0012] More preferably, the bottom of the discharge end of the mud-phosphorus distributor is provided with a detachable perforated plate, on which multiple spray holes are evenly distributed. Different specifications of perforated plates have different hole diameters, and the hole diameter of the spray holes can be adjusted by replacing the perforated plate.

[0013] Preferably, the belt is a polytetrafluoroethylene coated aramid belt to prevent mud and phosphorus from adhering to the belt and to extend the service life of the belt.

[0014] Preferably, the number of heating sections of the heat transfer oil heating plate is 3 to 5, and the temperature control device is a temperature sensor and a temperature control valve.

[0015] Preferably, the mud-phosphorus feed tank is equipped with a level gauge, and the vacuum pipeline is equipped with a vacuum pressure gauge and a regulating valve.

[0016] Preferably, the yellow phosphorus cooling spray tower is equipped with a spraying device inside, and the cooling medium is industrial water.

[0017] Preferably, the alkaline washing tower is filled with an alkaline washing solution, which is a sodium hydroxide aqueous solution with a mass percentage concentration of 5%-10%.

[0018] Another object of the present invention is to provide a continuous dehydration and phosphorus extraction process for mud phosphorus, using the above-mentioned equipment, including the following steps: (1) Pretreatment: Start the heat transfer oil heating plate and vacuum pump to make the temperature and vacuum in the vacuum sealing cavity reach the preset value; start the drive motor to drive the drum to rotate and drive the multi-layer belt to run continuously horizontally.

[0019] (2) Feeding and spreading: Start the conveying pump to transport the external mud and phosphorus to the mud and phosphorus feed tank; the mud and phosphorus are diverted to multiple mud and phosphorus feed pumps through the main pipeline, and after being pressurized, they are transported to each mud and phosphorus distributor in the vacuum-sealed cavity. Each mud and phosphorus distributor sprays the mud and phosphorus evenly onto the multi-layer belt.

[0020] (3) Vacuum heating and evaporation: Under the condition that the vacuum pump maintains the negative pressure inside the vacuum sealed cavity, the multi-layer belt carries the mud phosphorus horizontally from the feed end to the discharge end. The heat transfer oil heating plate heats the mud phosphorus on the belt in sections, so that the water and yellow phosphorus in the mud phosphorus evaporate into gaseous state in sequence and enter the upper vacuum port of the vacuum sealed cavity for discharge.

[0021] (4) Residue discharge: After evaporation, the mud and phosphorus residue is carried by the belt to the discharge end, falls into the receiving tank below, and is continuously discharged by the screw conveyor.

[0022] (5) Gas recovery and tail gas treatment: Under the action of the vacuum system, the water vapor and yellow phosphorus gas mixture in the vacuum-sealed cavity enters the yellow phosphorus cooling spray tower through the vacuum port at the top. The yellow phosphorus gas is condensed and precipitated into liquid yellow phosphorus and discharged from the bottom of the tower for collection. The remaining tail gas enters the alkaline washing tower, is absorbed and purified by alkaline washing liquid, and is then discharged into the air.

[0023] Preferably, in step (3), the heat transfer oil heating plate is divided into multiple heating sections along the belt running direction, and the temperature of each heating section gradually increases from the belt feed end to the discharge end. The temperature of the dehydration section is controlled at 100°C to 150°C, and the temperature of the phosphorus stripping section is controlled at 150°C to 250°C.

[0024] Preferably, in step (3), the running speed of the belt is controlled at 0.5-1.5 m / min; the vacuum degree of the vacuum sealing cavity is controlled at -0.06~-0.09 MPa.

[0025] Preferably, in step (5), the spraying temperature of the yellow phosphorus cooling spray tower is controlled between 40°C and 70°C.

[0026] Compared with the prior art, the advantages of the present invention are as follows: (1) Achieve continuous operation and improve processing efficiency: Through the coordinated operation of the feeding system, vacuum heating and evaporation system and residue discharge system, this invention achieves continuous operation of the entire process of mud phosphorus from feeding, dewatering, phosphorus stripping, residue discharge to gas recovery. It effectively overcomes the defects of low efficiency and high labor intensity of intermittent operation in the existing technology, greatly improves the industrial scale and efficiency of mud phosphorus treatment, and is suitable for large-scale mass production application.

[0027] (2) Precise temperature control and high yellow phosphorus recovery rate: The heat transfer oil heating plate is divided into multiple independent heating sections along the belt running direction. Each heating section can be individually temperature controlled. The temperature gradually increases from 100℃ to 250℃, realizing segmented and precise control of water evaporation and yellow phosphorus evaporation. This avoids the problem of yellow phosphorus loss due to excessively high temperature or incomplete evaporation due to excessively low temperature. The yellow phosphorus recovery rate can reach more than 90%, which is significantly improved, and the resource recovery benefits are significant.

[0028] (3) Safe and environmentally friendly, effectively controlling secondary pollution: The entire treatment process is carried out in a vacuum-sealed chamber, avoiding the safety hazards of yellow phosphorus coming into contact with air and causing combustion or leakage, and greatly improving operational safety; at the same time, yellow phosphorus is recovered through a yellow phosphorus cooling spray tower and tail gas is treated through an alkaline washing tower, achieving efficient recovery of yellow phosphorus, compliant emission of tail gas and resource utilization of residue, and compliant emission of wastewater and exhaust gas.

[0029] (4) The equipment has a compact structure and low energy consumption: the multi-layer belt stacking design greatly saves the equipment floor space; the segmented temperature control design can accurately supply heat according to the different needs of mud phosphorus dehydration and phosphorus stripping, avoiding the energy waste of the traditional overall heating method; the belt is made of high temperature resistant and non-phosphorus-stick polytetrafluoroethylene coated aramid belt, which reduces equipment wear and maintenance costs and extends the service life of the equipment.

[0030] (5) Significant economic and social benefits: This invention achieves efficient recovery of yellow phosphorus from mud phosphorus, improving the utilization rate of phosphorus resources; under vacuum conditions, the evaporation temperature of yellow phosphorus can be reduced to about 180°C, which greatly reduces the processing temperature and significantly reduces energy consumption; at the same time, it solves the environmental pollution problem caused by mud phosphorus stockpiling and protects the ecological environment; the equipment is stable in operation and easy to maintain, which can reduce the production cost and environmental protection cost of enterprises, and has important economic and social benefits and promotion and application value. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the mud phosphorus continuous dehydration and phosphorus extraction equipment in Embodiment 1 of the present invention.

[0032] Figure 2 This is a schematic diagram of the structure of the mud phosphorus continuous dehydration and phosphorus extraction equipment in Embodiment 2 of the present invention.

[0033] Wherein: 1 is mud phosphorus feed tank, 2 is conveying pump, 3 is main pipeline, 4 is mud phosphorus feed pump, 5 is vacuum sealed cavity, 6 is mud phosphorus distributor, 7 is belt, 8 is roller, 9 is heat transfer oil heating plate, 10 is receiving tank, 11 is screw conveyor, 12 is vacuum port, 13 is yellow phosphorus cooling spray tower, 14 is alkali washing tower, 15 is vacuum pump, and 16 is vacuum pipeline. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0035] like Figure 1 As shown, this is the mud-phosphorus continuous dewatering and phosphorus extraction equipment in Example 1.

[0036] A continuous dewatering and phosphorus extraction device for mud phosphorus includes a feeding system, a vacuum heating and evaporation system, a residue discharge system, a gas recovery and treatment system, and a vacuum system; The feeding system includes a mud-phosphorus feed tank 1, a conveying pump 2, and three mud-phosphorus feed pumps 4 connected in parallel. The conveying pump 2 is connected to an external mud-phosphorus storage device and the mud-phosphorus feed tank 1, specifically: the external mud-phosphorus storage device is connected to the feed end of the conveying pump 2, and the discharge end of the conveying pump 2 is connected to the top feed inlet of the mud-phosphorus feed tank 1. The bottom of the mud-phosphorus feed tank 1 is equipped with a main pipe 3, and the outlet end of the main pipe 3 branches to the feed ends of the three mud-phosphorus feed pumps 4 to realize the diversion and conveying of mud-phosphorus. The mud-phosphorus feed tank 1 is equipped with a level gauge to monitor the mud-phosphorus liquid level in the tank in real time to ensure stable feeding.

[0037] The vacuum heating evaporation system includes a vacuum-sealed chamber 5, three mud and phosphorus distributors 6, three layers of continuous horizontal running belts 7, six rollers 8, and three layers of heat-conducting oil heating plates 9, wherein belt 7 is a polytetrafluoroethylene coated aramid belt. The vacuum-sealed cavity 5 is a closed structure. One side has a feed inlet connected to the discharge end of the mud-phosphorus feed pump 4, and the other side has a residue discharge outlet. The mud-phosphorus distributor 6 is installed inside the vacuum-sealed cavity 5 near the feed inlet. Multiple mud-phosphorus distributors 6 are connected one-to-one with the discharge ends of each mud-phosphorus feed pump 4. Specifically, the mud-phosphorus distributor 6 adopts a cantilever beam structure. One end (fixed end) is installed on a fixed support at the feed inlet of the vacuum-sealed cavity 5 via a rotary joint. The rotary joint serves as both the feed inlet and the rotation fulcrum. Its feed end is connected to the discharge end of the mud-phosphorus feed pump 4 via a pipe. The discharge end of the rotary joint is connected to the main pipe of the mud-phosphorus distributor 6. A servo motor is installed on the fixed support and drives the main pipe of the mud-phosphorus distributor 6 to reciprocate around the rotary joint via an eccentric wheel and connecting rod. The reciprocating swing direction is along the running direction of the belt 7. The bottom of the material end is provided with multiple evenly distributed spray holes (the bottom of the discharge end of the mud and phosphorus distributor 6 is provided with a detachable perforated plate, on which multiple spray holes are evenly distributed. Different specifications of perforated plates have different hole diameters, and the hole diameter of the spray holes can be adjusted by replacing the perforated plate). With the left and right swing of the mud and phosphorus distributor 6, the mud and phosphorus are ensured to be evenly distributed on the belt 7, avoiding local accumulation that would lead to uneven heating. The three layers of belts 7 are arranged at intervals in the vertical direction. The two ends of each layer of belt 7 are respectively fitted onto the corresponding rollers 8. The rollers 8 are connected to the drive motor. The drive motor drives the rollers 8 to rotate, thereby driving the belt 7 to run continuously horizontally, realizing the continuous conveying of mud and phosphorus. Each layer of belt 7 includes an upper horizontal section and a lower return section. The heat transfer oil heating plate 9 is fixed on the side wall of the vacuum sealed cavity 5 by a support bracket and is only arranged below the upper horizontal running section of the belt 7, avoiding the area of ​​the rollers 8 at both ends. The bottom of the support bracket is equipped with an adjusting screw to adjust the gap between the upper surface of the heat transfer oil heating plate 9 and the lower surface of the belt 7. The gap is controlled within the range of 5-15mm. The heat transfer oil heating plate 9 is fixed under each layer of belt 7, which not only supports the belt 7, but also provides a heat source for the mud and phosphorus on the belt 7. The heat transfer oil heating plate 9 is divided into three independent heating sections along the running direction of the belt 7. Each heating section is equipped with an independent temperature control device, which is a temperature sensor and a temperature control valve. It can realize individual temperature control. The temperature can be freely controlled from 100℃ to 250℃ from the feed end to the discharge end of the belt, so as to meet the different temperature requirements of mud and phosphorus dehydration and yellow phosphorus evaporation.

[0038] The residue discharge system includes a receiving tank 10 and a screw conveyor 11. The receiving tank 10 is located below the residue discharge port of the vacuum-sealed cavity 5 and is used to receive the mud and phosphorus residue falling from the discharge end of the belt 7. The screw conveyor 11 is connected to the receiving tank 10 and is used to continuously discharge the mud and phosphorus residue in the receiving tank 10 to achieve the harmless disposal or secondary utilization of the residue.

[0039] The gas recovery and treatment system includes a yellow phosphorus cooling spray tower 13 and an alkaline scrubbing tower 14. The inlet of the yellow phosphorus cooling spray tower 13 is connected to two vacuum ports 12 at the top of the vacuum-sealed cavity 5 via a pipe to receive a mixture of water vapor and yellow phosphorus gas extracted from the vacuum-sealed cavity 5. The yellow phosphorus cooling spray tower 13 is equipped with a spraying device that sprays a cooling medium, which is industrial water, to condense the yellow phosphorus gas into liquid yellow phosphorus. The liquid yellow phosphorus is discharged and collected from the outlet at the bottom of the yellow phosphorus cooling spray tower. The inlet of the alkaline scrubbing tower 14 is connected to the tail gas outlet of the yellow phosphorus cooling spray tower 13. The alkaline scrubbing tower 14 is filled with an alkaline scrubbing liquid (preferably sodium hydroxide solution) to absorb acidic impurities in the tail gas.

[0040] The vacuum system includes a vacuum pump 15 and a vacuum pipeline 16. The vacuum port 12 at the top of the vacuum-sealed cavity 5 is connected in sequence to the yellow phosphorus cooling spray tower 13, the alkaline washing tower 14, and the vacuum pump 15 through the vacuum pipeline 16. After the vacuum pump 15 is started, the mixture of water vapor and yellow phosphorus vapor in the vacuum-sealed cavity 5 is extracted through the vacuum port 12 and first enters the yellow phosphorus cooling spray tower 13 to condense the yellow phosphorus vapor into liquid yellow phosphorus. The uncondensed tail gas then enters the alkaline washing tower 14 for absorption and purification. The purified gas is finally discharged through the vacuum pump 15. The vacuum pipeline 16 is equipped with a vacuum pressure gauge and a regulating valve for monitoring and adjusting the vacuum level.

[0041] A continuous dehydration and phosphorus extraction process for mud phosphorus, using the aforementioned equipment, processes mud phosphorus raw materials. The main components of the mud phosphorus raw materials are: yellow phosphorus content 30.6 wt%, moisture content 55.2 wt%, and solid impurities (mud, silicates, etc.) 14.2 wt%. The specific steps are as follows: (1) Pretreatment: Start the heating system of the heat transfer oil heating plate 9 and set the temperature of each heating section as follows: first section (dehydration section) 120℃, second section (transition section) 180℃, third section (phosphorus stripping section) 230℃. Start the vacuum pump 15 and extract the gas in the vacuum sealed cavity 5 through the vacuum pipeline 16, and adjust the regulating valve on the vacuum pipeline to stabilize the vacuum degree in the vacuum sealed cavity 5 at -0.07MPa (gauge pressure). At the same time, start the drive motor to drive the drum 8 to rotate, and drive the three-layer continuous horizontal belt 7 to run at a speed of 0.8m / min.

[0042] (2) Feeding and Distribution: Start the conveying pump 2 to transport the mud and phosphorus from the external mud and phosphorus storage device to the mud and phosphorus feeding tank 1. Monitor the liquid level in the tank using a level gauge and maintain the liquid level in the mud and phosphorus feeding tank 1 between 1 / 2 and 2 / 3 of the tank volume. The mud and phosphorus flows out through the main pipe 3 at the bottom of the mud and phosphorus feeding tank 1 and is distributed to three parallel mud and phosphorus feeding pumps 4. Each mud and phosphorus feeding pump 4 pressurizes the mud and phosphorus and then delivers it to the three corresponding mud and phosphorus distributors 6 in the vacuum-sealed cavity 5. Start the servo motor of the mud and phosphorus distributor 6 to drive the mud and phosphorus distributor 6 to swing back and forth along the belt running direction at a frequency of 15 times / minute. At the same time, the mud and phosphorus is evenly sprayed onto the surface of the three-layer belt 7 through the spray hole at the bottom of the discharge end of the mud and phosphorus distributor 6. On-site observation shows that the mud and phosphorus coverage thickness on the belt surface is uniform, with no local accumulation.

[0043] (3) Vacuum heating and evaporation: Under the continuous action of vacuum pump 15, a stable vacuum environment of -0.07MPa is maintained inside the vacuum sealed cavity 5. The three-layer belt 7 carries the mud phosphorus from the feed end to the discharge end and moves horizontally continuously. The horizontal length of the belt is 10.0 meters. During the movement, the mud phosphorus passes through three heating sections in sequence: the first section (dehydration section, temperature 120℃): the free water and some bound water in the mud phosphorus evaporate rapidly into water vapor, and the water vapor enters the upper space of the vacuum sealed cavity 5 under the action of vacuum; the second section (transition section, temperature 180℃): the residual water continues to evaporate, and at the same time the temperature of the mud phosphorus further increases, preparing for the evaporation of yellow phosphorus; the third section (phosphorus evaporation section, temperature 230℃): the yellow phosphorus in the mud phosphorus reaches the boiling point and is rapidly vaporized into yellow phosphorus vapor under vacuum conditions, which also enters the upper space of the vacuum sealed cavity 5. The total residence time of the mud phosphorus on the belt is 12.5 minutes.

[0044] (4) Residue discharge: After the moisture and yellow phosphorus have evaporated, the mud-phosphorus slag is carried by the conveyor belt 7 to the discharge end and automatically falls into the receiving tank 10 below under gravity. The test results showed that no residual elemental yellow phosphorus was detected in the mud-phosphorus slag, the phosphate content (calculated as P2O5) was 11.3%, and the moisture content was less than 0.1 wt%. The screw conveyor 11 is started to continuously discharge the mud-phosphorus slag in the receiving tank 10.

[0045] (5) Gas recovery and tail gas treatment: Under the action of the vacuum system, the mixture of water vapor and yellow phosphorus vapor in the upper space of the vacuum-sealed cavity 5 is extracted through the vacuum port 12 at the top and enters the yellow phosphorus cooling spray tower 13 through the pipeline. The spray device in the yellow phosphorus cooling spray tower 13 sprays industrial water at 45°C, and the yellow phosphorus vapor is condensed and precipitated into liquid yellow phosphorus, which is deposited at the bottom of the tower and periodically discharged and collected from the outlet. According to statistics, in this embodiment, the amount of yellow phosphorus that can be recovered from processing 1 ton of mud phosphorus is 298.5 kg, which is equivalent to a yellow phosphorus recovery rate of 97.5%.

[0046] The exhaust gas (mainly containing a small amount of uncondensed water vapor and trace amounts of acidic impurities) after being treated by the yellow phosphorus cooling spray tower 13 enters the alkaline scrubbing tower 14. The alkaline scrubbing tower 14 contains an 8wt% sodium hydroxide solution. Acidic impurities in the exhaust gas (such as P2O5, H3PO4, etc.) are absorbed by the alkaline solution. The purified exhaust gas is finally discharged through the vacuum pump 15. Testing shows that the phosphorus content in the exhaust gas is <1.0 mg / m³. 3 The phosphate content meets the requirements of GB 16297-1996 "Integrated Emission Standard for Air Pollutants".

[0047] Furthermore, this embodiment operated continuously for 72 hours with stable equipment operation and consistent parameter control. No safety incidents such as spontaneous combustion or leakage of yellow phosphorus occurred during this period. The liquid level in the mud phosphorus feed tank 1, the vacuum degree in the vacuum sealing chamber 5, the temperatures of each heating section, the spray temperature of the yellow phosphorus cooling spray tower 13, and the concentration of the washing liquid in the alkali washing tower 14 were all maintained within the set ranges. During shutdown inspection, no obvious mud phosphorus adhered to the surface of the conveyor belt 7, and the spray holes of the mud phosphorus distributor 6 were unblocked, indicating that equipment maintenance was simple. Example 2

[0048] like Figure 2 As shown, this is the mud-phosphorus continuous dehydration and phosphorus extraction equipment in Example 2.

[0049] A continuous dehydration and phosphorus extraction process for mud phosphorus uses the same equipment as in Example 1 to process the mud phosphorus raw material. The only difference in equipment is that there are five mud phosphorus feed pumps 4, five layers of belt conveyors 7, five mud phosphorus distributors 6, ten rollers 8, and five layers of heat transfer oil heating plates 9. The main components of the mud phosphorus raw material are: yellow phosphorus content 24.8 wt%, moisture content 58.6 wt%, and solid impurities (mud, silicates, etc.) 16.6 wt%. The specific steps are as follows: (1) Pretreatment: Start the heating system of the heat transfer oil heating plate 9 and set the temperature of each heating section as follows: first section (dehydration section) 100℃, second section (dehydration / transition section) 150℃, third section (transition section) 200℃, fourth section (phosphorus stripping section) 230℃, fifth section (phosphorus stripping section) 250℃ (this embodiment uses five-section heating to improve temperature control accuracy). Start the vacuum pump 15 to stabilize the vacuum degree in the vacuum sealing cavity 5 at -0.09MPa (gauge pressure). Start the drive motor to drive the five-layer continuously horizontally running belt 7 to run at a speed of 0.6m / min.

[0050] (2) Feeding and Distribution: Start the conveying pump 2 to transport the mud and phosphorus from the external mud and phosphorus storage device to the mud and phosphorus feeding tank 1. Monitor the liquid level in the tank using a level gauge and maintain the liquid level in the mud and phosphorus feeding tank 1 between 1 / 2 and 2 / 3 of the tank volume. The mud and phosphorus flows out through the main pipe 3 at the bottom of the mud and phosphorus feeding tank 1 and is distributed to five parallel mud and phosphorus feeding pumps 4. Each mud and phosphorus feeding pump 4 pressurizes the mud and phosphorus and then delivers it to the five mud and phosphorus distributors 6 in the vacuum-sealed cavity 5. The five mud and phosphorus distributors 6 correspond to the five belts 7. Start the servo motor of the mud and phosphorus distributor 6 to drive the mud and phosphorus distributor 6 to swing back and forth along the belt running direction at a frequency of 12 times / minute. At the same time, the mud and phosphorus is evenly sprayed onto the surface of the five belts 7 through the replaceable nozzles at the bottom of the mud and phosphorus distributor 6. On-site observation shows that the mud and phosphorus coverage thickness on the belt surface is uniform, with no local accumulation.

[0051] (3) Vacuum heating and evaporation: Under a vacuum environment of -0.09 MPa, belt 7 runs at a speed of 0.6 m / min, with a total belt length of 10.0 m. The mud phosphorus passes through five heating sections on the belt in sequence: the first section (100℃): mainly evaporates free water; the second section (150℃): continues to evaporate moisture, and the residual moisture is basically evaporated; the third section (200℃): the mud phosphorus temperature rises, and yellow phosphorus begins to evaporate; the fourth section (230℃): yellow phosphorus evaporates in large quantities; the fifth section (250℃): the residual yellow phosphorus is completely evaporated, ensuring that the residual amount of yellow phosphorus in the mud phosphorus slag is extremely low. The total residence time of the mud phosphorus on the belt is about 16.7 minutes to accommodate the full treatment of mud phosphorus with high moisture content.

[0052] (4) Residue discharge: Same as in Example 1. The residue of elemental yellow phosphorus in the mud phosphorus slag was not detected, the phosphate content (calculated as P2O5) was 10.8%, and the moisture content was less than 0.1 wt%. The mud phosphorus slag was discharged by screw conveyor 11.

[0053] (5) Gas recovery and tail gas treatment: Under the action of the vacuum system, the mixture of water vapor and yellow phosphorus vapor in the upper space of the vacuum-sealed cavity 5 is extracted through the vacuum port 12 at the top and enters the yellow phosphorus cooling spray tower 13 through the pipeline. The spray device in the yellow phosphorus cooling spray tower 13 sprays industrial water at 50°C, and the yellow phosphorus vapor is condensed and precipitated into liquid yellow phosphorus, which is deposited at the bottom of the tower and periodically discharged and collected from the outlet. According to statistics, in this embodiment, the amount of yellow phosphorus that can be recovered from processing 1 ton of mud phosphorus is 238.1 kg, which is equivalent to a yellow phosphorus recovery rate of 96.0%.

[0054] The exhaust gas (mainly containing a small amount of uncondensed water vapor and trace amounts of acidic impurities) after being treated by the yellow phosphorus cooling spray tower 13 enters the alkaline scrubbing tower 14. The alkaline scrubbing tower 14 contains an 8wt% sodium hydroxide solution. The acidic impurities in the exhaust gas (such as P2O5, H3PO4, etc.) are absorbed by the alkaline solution. The purified exhaust gas is finally discharged by the vacuum pump 15. The yellow phosphorus content in the exhaust gas is found to be <1.0 mg / m³. 3 The phosphate content meets the requirements of GB 16297-1996 "Integrated Emission Standard for Air Pollutants".

[0055] Furthermore, this embodiment operated continuously for 72 hours with stable equipment operation and consistent parameter control. No safety incidents such as spontaneous combustion or leakage of yellow phosphorus occurred during this period. The liquid level in the mud phosphorus feed tank 1, the vacuum degree in the vacuum sealing chamber 5, the temperatures of each heating section, the spray temperature of the yellow phosphorus cooling spray tower 13, and the concentration of the washing liquid in the alkali washing tower 14 were all maintained within the set ranges. During shutdown inspection, no obvious mud phosphorus adhered to the surface of the conveyor belt 7, and the spray holes of the mud phosphorus distributor 6 were unblocked, indicating that equipment maintenance was simple.

[0056] In addition to the above embodiments, the present invention also includes other embodiments. All technical solutions formed by equivalent transformation or equivalent substitution should fall within the protection scope of the claims of the present invention.

Claims

1. A continuous dewatering and phosphorus extraction device for mud phosphorus, characterized in that: It includes a feeding system, a vacuum heating and evaporation system, a residue discharge system, a gas recovery and treatment system, and a vacuum system; The feeding system includes a mud-phosphorus feed tank (1), a conveying pump (2) and multiple mud-phosphorus feed pumps (4). The conveying pump (2) is connected to an external mud-phosphorus storage device and the mud-phosphorus feed tank (1). The bottom of the mud-phosphorus feed tank (1) is provided with a main pipe (3). The outlet end of the main pipe (3) is branched to the feed end of multiple mud-phosphorus feed pumps (4). The vacuum heating evaporation system includes a vacuum sealed cavity (5), multiple mud and phosphorus distributors (6), multiple layers of continuous horizontal running belts (7), multiple rollers (8), and multiple layers of heat transfer oil heating plates (9). The vacuum sealed cavity (5) has a feed port on one side connected to the discharge end of the mud and phosphorus feed pump (4), and a residue discharge port on the other side. The mud and phosphorus distributors (6) are installed in the vacuum sealed cavity (5) and are connected to the discharge ends of each mud and phosphorus feed pump (4) in a corresponding manner. The multiple layers of belts (7) are fitted on the rollers (8) and driven by a drive motor. The heat transfer oil heating plates (9) are fixed below each layer of belts (7). The heat transfer oil heating plates (9) are divided into multiple independent heating sections along the belt running direction, and each heating section is equipped with an independent temperature control device. The residue discharge system includes a receiving tank (10) and a screw conveyor (11). The receiving tank (10) is located below the residue discharge port of the vacuum-sealed cavity (5), and the screw conveyor (11) is connected to the receiving tank (10). The gas recovery and treatment system includes a yellow phosphorus cooling spray tower (13) and an alkaline washing tower (14). The air inlet of the yellow phosphorus cooling spray tower (13) is connected to the vacuum port (12) at the top of the vacuum sealing cavity (5), and the air inlet of the alkaline washing tower (14) is connected to the tail gas outlet of the yellow phosphorus cooling spray tower (13). The vacuum system includes a vacuum pump (15) and a vacuum pipeline (16). The vacuum port (12) at the top of the vacuum sealed cavity (5) is connected in sequence to the yellow phosphorus cooling spray tower (13), the alkali washing tower (14) and the vacuum pump (15) through the vacuum pipeline 16.

2. The continuous dewatering and phosphorus extraction equipment for mud and phosphorus according to claim 1, characterized in that: The mud and phosphorus distributor (6) is fixed at one end to the feed end of the belt, and the other end is driven by a servo motor to swing back and forth along the belt running direction. The bottom of the discharge end of the mud and phosphorus distributor is provided with multiple spray holes.

3. The continuous dewatering and phosphorus extraction equipment for mud and phosphorus according to claim 1, characterized in that: The belt (7) is a polytetrafluoroethylene coated aramid belt. The belt (7) includes an upper horizontal section and a lower return section. The heat transfer oil heating plate (9) is fixed on the upper horizontal running section of each belt.

4. The continuous dewatering and phosphorus extraction equipment for mud and phosphorus according to claim 1, characterized in that: The number of heating sections of the heat transfer oil heating plate (9) is 3 to 5, and the temperature control device is a temperature sensor and a temperature control valve.

5. The continuous dewatering and phosphorus extraction equipment for mud and phosphorus according to claim 1, characterized in that: The mud-phosphorus feed tank (1) is equipped with a level gauge, and the vacuum pipeline (16) is equipped with a vacuum pressure gauge and a regulating valve.

6. The continuous dewatering and phosphorus extraction equipment for mud and phosphorus according to claim 1, characterized in that: The yellow phosphorus cooling spray tower (13) is equipped with a spraying device inside, and its cooling medium is industrial water.

7. The continuous dewatering and phosphorus extraction equipment for mud and phosphorus according to claim 1, characterized in that: The alkaline washing tower (14) is filled with alkaline washing liquid.

8. A continuous dewatering and phosphorus extraction process for mud phosphorus, using the equipment described in any one of claims 1 to 7, characterized in that: Includes the following steps: (1) Pretreatment: Start the heat transfer oil heating plate (9) and vacuum pump (15) to make the temperature and vacuum degree in the vacuum sealing cavity (5) reach the preset value; start the drive motor to drive the drum (8) to rotate and drive the multi-layer belt (7) to run continuously horizontally; (2) Feeding and spreading: Start the conveying pump (2) to transport the external mud and phosphorus to the mud and phosphorus feed tank (1); the mud and phosphorus are diverted to multiple mud and phosphorus feed pumps (4) through the main pipeline (3), and after being pressurized, they are transported to each mud and phosphorus distributor (6) in the vacuum sealed cavity (5). Each mud and phosphorus distributor (6) sprays the mud and phosphorus evenly onto the multi-layer belt (7); (3) Vacuum heating evaporation: Under the condition that the vacuum pump (15) maintains the negative pressure inside the vacuum sealed cavity (5), the multi-layer belt (7) carries the mud phosphorus horizontally from the feed end to the discharge end. The heat transfer oil heating plate (9) heats the mud phosphorus on the belt in sections, so that the water and yellow phosphorus in the mud phosphorus evaporate into gaseous state in sequence, enter the upper space of the vacuum sealed cavity (5), and are discharged through the vacuum port (12); (4) Residue discharge: After evaporation, the mud and phosphorus residue is transported to the discharge end by the belt (7), falls into the receiving tank (10) below, and is continuously discharged by the screw conveyor (11); (5) Gas recovery and tail gas treatment: Under the action of the vacuum system, the mixture of water vapor and yellow phosphorus gas in the vacuum sealed cavity (5) enters the yellow phosphorus cooling spray tower (13) through the vacuum port (12) at the top. The yellow phosphorus gas is condensed and precipitated into liquid yellow phosphorus and discharged from the bottom of the tower for collection. The remaining tail gas enters the alkaline washing tower (14), and is discharged after being absorbed and purified by alkaline washing liquid.

9. The continuous dewatering and phosphorus extraction process for mud phosphorus according to claim 8, characterized in that: In step (3), the heat transfer oil heating plate (9) is divided into multiple heating sections along the belt running direction. The temperature of each heating section gradually increases from the belt feed end to the discharge end. The temperature of the dehydration section is controlled at 100℃ to 150℃, and the temperature of the phosphorus stripping section is controlled at 150℃ to 250℃.

10. The continuous dewatering and phosphorus extraction process for mud phosphorus according to claim 8, characterized in that: In step (3), the running speed of the belt (7) is controlled at 0.5-1.5 m / min; the vacuum degree of the vacuum sealing cavity (5) is controlled at -0.06~-0.09 MPa.

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