Method for determining the solid content of sludge phosphorus

Abstract

The present application relates to yellow phosphorus production technical field, and relates to a kind of determination method of solid content in mud phosphorus;For the problems such as incomplete solid-liquid separation, yellow phosphorus volatile, determination error and poor operation safety in prior art, the device of the present application adopts integrated sealing design, built-in quartz funnel supported in wide-mouth bottle by gas-permeable quartz sand layer, bottle cap is provided with inert gas inlet and outlet, bottle bottom is provided with drain, funnel below is provided with exhaust port connected with vacuum system.Determination method includes: under the protection of argon, mud phosphorus sample is introduced, vacuum filtration is carried out to realize solid-liquid separation, then the device is placed in 30~50 ℃ constant temperature water bath, and inert gas low-temperature air flow is introduced to dry to constant weight, and the solid content is calculated according to the mass difference before and after drying.The present application combines inert atmosphere protection, vacuum filtration and low-temperature drying organically, significantly reduces the loss of yellow phosphorus volatilization, the determination result is accurate and reliable, operation is safe and environmentally friendly, and provides efficient technical means for yellow phosphorus production.

Description

Technical Field

[0001] This invention relates to the field of yellow phosphorus detection technology, and in particular to a method for determining the solid content in mud phosphorus. Background Technology

[0002] In the electric furnace process for producing yellow phosphorus, phosphorus vapor escaping from the furnace often carries with it a large amount of unreacted raw material dust (such as phosphate rock powder, coke powder, and silica powder) and slag powder. These particles undergo complex mechanical mixing, encapsulation, and adsorption with the condensed yellow phosphorus droplets and process water in the subsequent spray condensation system, forming a stable multiphase mixture known as "mud phosphorus." The physicochemical properties of mud phosphorus are complex, and its solid content (referred to as "solid content") is a key process indicator directly reflecting the internal reaction efficiency of the electric furnace, the operation of the furnace gas purification system, and the phosphorus resource recovery rate. Therefore, rapid, accurate, and safe determination of mud phosphorus solid content is indispensable for achieving refined operation, process optimization, energy consumption reduction, and environmental compliance management in yellow phosphorus production.

[0003] Currently, research on the resource utilization of mud phosphorus largely focuses on technologies for recovering yellow phosphorus, such as chemical precipitation, ion exchange, solvent extraction, or distillation. However, methods and standardized equipment specifically designed for accurately determining the solid content of mud phosphorus are rarely reported. Existing related technologies often overlook or fail to effectively address the following core challenges in mud phosphorus treatment: Incomplete solid-liquid separation: For example, the solution disclosed in Chinese patent CN202220191498.4 uses a scraper to collect the sediment after drainage, resulting in high residual moisture in the obtained solid, making it impossible to obtain the quality of dried solid. Patent CN202221242962.4 uses a screw press dehydrator, which suffers from a "two-way entrainment" problem where the solid phase carries liquid and the liquid phase carries solid, resulting in limited separation efficiency and affecting the accuracy of subsequent measurements.

[0004] 2. Loss due to easy volatilization of yellow phosphorus: The elemental phosphorus (yellow phosphorus) in mud phosphorus has a melting point of 44.1 ℃ and can volatilize at room temperature. It is also prone to spontaneous combustion upon contact with air. Patent CN202410133027.1 describes transferring the separated solids to a heating tank and drying them at 100 ℃. This high-temperature process leads to vigorous volatilization of yellow phosphorus. This not only results in a lower-than-expected solid content reading but also causes serious material loss, safety risks, and environmental pollution.

[0005] 3. Complex process and inability to isolate air: The multiple sample transfers and open operations involved in the above patents cannot effectively isolate air during the measurement process, which exacerbates the oxidation and volatilization of yellow phosphorus.

[0006] In summary, developing a device and method for efficient, mild, and accurate solid-liquid separation and solid drying of mud-phosphorus under a fully inert atmosphere has become a critical technological bottleneck in this field. Based on this, the present invention proposes an innovative solution. Summary of the Invention

[0007] The primary objective of this invention is to overcome the shortcomings of the prior art and provide a method and apparatus for determining the solid content in mud phosphorus, so as to systematically solve the problems of low solid-liquid separation efficiency, easy volatilization loss of yellow phosphorus, poor operational safety, and low accuracy of determination results during the mud phosphorus determination process.

[0008] To achieve the above objectives, the present invention adopts the following integrated technical concept: innovating the integration of inert gas protection technology, vacuum negative pressure filtration technology and low temperature water bath drying technology, and designing a closed and continuous measurement system and process flow to ensure that the entire process from sample introduction to final weighing is carried out in an oxygen-free and low-temperature controlled environment.

[0009] Firstly, a method for determining the solid content in mud phosphorus includes the following steps: S1. Apparatus preparation: Remove the cap of the wide-mouth bottle, fold the filter paper and place it in the quartz funnel, tighten the cap, and weigh the wide-mouth bottle and its internal components used to determine the solid content in mud phosphorus. Record the mass M of the empty apparatus. S2. Establishment of inert atmosphere and sample injection: Inert gas is introduced into the apparatus to replace the air, and the mass of the sample is measured. The mud phosphorus sample was placed in a quartz funnel; S3. Vacuum filtration: Under the protection of inert gas, the vacuum pump is turned on to evacuate the filtrate chamber, so that the liquid components in the mud phosphorus sample pass through the quartz sand layer and enter the filtrate chamber, while the solids are retained in the quartz funnel. S4. Filtrate discharge, filtration ends, restore the device to normal pressure, and discharge the liquid in the filtrate chamber; S5. Low-temperature inert gas drying: Place the apparatus in a constant temperature environment of 30–50°C and continuously introduce inert gas into the apparatus until the total mass of the apparatus and the retained solid reaches a constant weight, denoted as S5. ; S6. Calculate according to the following formula. Calculate the solid content of the mud phosphorus, where w is the solid content of the mud phosphorus and M is the mass of the empty unit. For the quality of mud phosphorus samples, This refers to the total mass of the apparatus and the retained solids after drying to constant weight.

[0010] As a preferred technical solution, filter paper compatible with quartz is taken, folded, and placed in a quartz funnel.

[0011] As a preferred technical solution, in step S3, the inert gas is argon, and during the filtration process, argon is introduced into the device at a flow rate of 50-300 mL / min.

[0012] As a preferred technical solution, in step S5, the inert gas is argon, the argon flow rate during the drying process is 50-150 mL / min, and the constant temperature environment is provided by a water bath.

[0013] As a preferred technical solution, in step S5, the criterion for determining constant weight is that the absolute value of the difference between the two weighings obtained at a time interval of 20 minutes is not greater than 0.1 g.

[0014] As a preferred technical solution, the filtration time in step S3 is 20 to 90 minutes.

[0015] As a preferred technical solution, in step S5, the exhaust gas is treated with sodium hypochlorite at a concentration of 3-10 wt.%. Most preferably, the exhaust gas is treated with sodium hypochlorite at a concentration of 5 wt.%.

[0016] Secondly, the present invention provides an apparatus for the above method, comprising a wide-mouth bottle, wherein the bottle cap of the wide-mouth bottle is provided with an air inlet and an air outlet with valves, the bottle cap is connected to the air inlet pipe and the air outlet pipe by a leak-proof sealing ring, and the bottom of the bottle body of the wide-mouth bottle is provided with a drain outlet with a first sealing element. A quartz funnel is fixed inside the wide-mouth bottle by a breathable quartz sand layer, and the quartz sand layer and the quartz funnel are sintered together. A filtration chamber is formed between the bottom of the quartz funnel and the bottom of the wide-mouth bottle. The air extraction port is located on the wall of the wide-mouth bottle and communicates with the filtrate chamber. The air extraction port also has a removable second seal.

[0017] As a preferred technical solution, the particle size of the breathable quartz sand layer ranges from 50 to 200 mesh, and the layer thickness is 8 to 12 mm. Most preferably, the layer thickness is 10 mm.

[0018] As a preferred technical solution, the air extraction port is detachably connected to one end of the pipeline, and the other end of the pipeline is connected to the vacuum pump through an anti-backflow device; the anti-backflow device is one of a safety bottle, a buffer bottle, and a check valve.

[0019] As a preferred technical solution, the system also includes a water bath, in which the wide-mouth bottle is placed; and the gas outlet pipe is connected to the gas washing bottle.

[0020] Compared with the prior art, the advantages of the present invention are: Compared to existing technologies, this invention integrates the three stages of "protection, separation, and drying" into a continuous and controllable process flow, and combines this with an integrated structural design of "filtration-support-ventilation," achieving a more efficient and safer determination of mud phosphorus solids content. Its main advantages are: The accuracy of the determination is significantly improved: efficient primary solid-liquid separation is achieved through vacuum filtration, greatly reducing the amount of bound water that needs to be removed by drying; subsequent strict low-temperature (<50 ℃) drying is carried out under an inert gas flow, which minimizes the volatilization of yellow phosphorus. The combination of these two methods ensures that the final measured solid mass is close to its true dry basis mass, making the solid content determination results more reliable.

[0021] Operational safety and environmental friendliness are greatly improved: The entire process is carried out in a closed system under argon protection, completely eliminating the possibility of yellow phosphorus coming into contact with air, fundamentally eliminating the risks of spontaneous combustion and explosion, as well as the resulting environmental pollution. The exhaust port can be connected to a tail gas treatment device to further ensure environmental safety.

[0022] Improved efficiency and reduced energy consumption: Vacuum pre-dehydration reduces the drying load by approximately 30%-50%, significantly shortening the total time required to reach constant weight (compared to the control group without vacuum filtration, drying time can be reduced by more than 20%). Furthermore, low-temperature drying also reduces energy consumption compared to traditional high-temperature drying methods.

[0023] The device is simple and the process is seamless: the device is highly integrated, and the sample does not need to be moved between multiple containers for separation, transfer and drying, which avoids transfer loss and secondary contamination, simplifies operation and reduces human error. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the measuring device of the present invention in the filtration state; Figure 2 This is a schematic diagram of the structure of the measuring device of the present invention in the drying state; Among them, 1-wide-mouth bottle; 2-bottle cap; 3-air inlet; 4-air outlet; 5-first seal; 6-drain outlet; 7-quartz funnel; 8-permeable quartz sand layer; 9-filtrate chamber; 10-air extraction port; 11-safety bottle; 12-vacuum pump; 13-second seal; 15-water bath; 16-gas washing bottle. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed in accordance with the techniques or conditions described in the literature in the art or according to the product manual.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0027] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1

[0029] Step 1: Equipment preparation and weighing of empty equipment according to Figure 1 The assembly of the measuring device is shown. The bottle cap (2) of the wide-mouth bottle (1) is provided with an air inlet (3) and an air outlet (4) with valves, and the bottom of the bottle is provided with a drain outlet (6) with a first seal (5). The quartz funnel (7) is fixedly supported inside the wide-mouth bottle (1) by a layer of breathable quartz sand (8). The quartz sand layer and the quartz funnel are sintered together, the sand grain size is 100 mesh, and the layer thickness is 10 mm. A filtrate chamber (9) is formed between the bottom of the quartz funnel (7) and the bottom of the bottle. The air extraction port (10) is provided on the bottle wall and communicates with the filtrate chamber (9). The air extraction port is provided with a removable second seal (13).

[0030] Take a 9 cm diameter filter paper, fold it and put it into the quartz funnel (7), tighten the bottle cap (2), weigh the wide-mouth bottle and its internal components, and record the mass of the empty device. =537.20 g.

[0031] Step 2: Sample injection and establishment of inert atmosphere Stir the settled mud-phosphorus sample thoroughly with a stirring rod, take a sample into a beaker, and weigh the sample. =21.80 g, and then the sample was transferred to the quartz funnel (7) of the wide-mouth bottle. The drain outlet (6) was sealed with the first sealing element (5), and argon was used as the carrier gas. The inlet valve and outlet valve were opened, and the flow rate was set to 200 mL / min to purge the device for 5 min. The first sealing element (5) is a piston.

[0032] Step 3: Vacuum filtration After 5 minutes, adjust the valve and remove the second seal (13) from the suction port (10). Connect the vacuum pump (12) to the safety bottle (11) through the pipeline, and then connect the end of the pipeline to the suction port (10) of the wide-mouth bottle (1). Ensure that all connections are sealed well. Adjust the argon flow rate to 100 mL / min, turn on the vacuum pump (12), and evacuate the filtrate chamber (9) for 30 minutes. Under negative pressure, the liquid components in the mud phosphorus sample quickly pass through the quartz sand layer (8) and enter the filtrate chamber (9), while the solid particles are trapped on the filter paper in the quartz funnel (7).

[0033] After the filtration is completed, turn off the vacuum pump (12), open the air inlet valve to balance the negative pressure of the device, and when the device pressure returns to atmospheric pressure, remove the vacuum pump (12) and its connecting pipeline, and reseal the air extraction port (10) with the second sealing element (13).

[0034] Step 4: Filtrate discharge Open the first seal (5) of the drain outlet (6) and pour out the water that has been filtered to the bottom of the wide-mouth bottle. Then reseal the drain outlet with the first seal (5). Weigh the entire wide-mouth bottle at this point and record the weight. =550.93 g.

[0035] Step 5: Low-temperature inert airflow drying like Figure 2 As shown, the drained device was placed in a water bath (15), and the water bath temperature was set to 35°C. The inlet valve and outlet valve were opened, and the outlet was connected to a gas washing bottle (16) containing 5 wt.% sodium hypochlorite solution for tail gas treatment. The argon flow rate was set to 100 mL / min and continuously introduced.

[0036] During this process, the apparatus is intermittently removed, and the condensate on the outer wall of the wide-mouth bottle (1) is wiped clean with absorbent paper before weighing. The drying endpoint is reached when the apparatus reaches a constant weight; the weight of the apparatus at this point is recorded as... =546.92 g. Total drying time was 6.4 h.

[0037] Step 6: Solid content calculation Calculate the solid phosphorus content in mud using the formula: =1- =0.4459 0.4459 × 100% = 44.59% Solid content in mud phosphorus: 44.59%. Example 2

[0038] Step 1: Equipment preparation and weighing of empty equipment Assemble the basic structure of the device using the same method as in Example 1, weigh the wide-mouth bottle and its internal components, and record the mass of the empty device. =537.18 g. At this time, the vacuum pump and connecting pipelines have not yet been installed.

[0039] Step 2: Sample injection and establishment of inert atmosphere Stir the settled mud-phosphorus sample thoroughly with a stirring rod, take a sample into a beaker, and weigh the sample. =23.65 g, and then the sample was transferred to a quartz funnel. The drain outlet was sealed with the first sealing element, and argon was used as the carrier gas to purge the inside of the device at a flow rate of 200 mL / min for 5 min.

[0040] Step 3: Install the filtration assembly and perform vacuum filtration. Remove the second seal from the extraction port and install the vacuum pump, safety bottle, and connecting tubing. Adjust the argon flow rate to 100 mL / min, turn on the vacuum pump, and perform filtration for 50 minutes.

[0041] After filtration is completed, turn off the vacuum pump, balance the negative pressure, remove the vacuum pump and connecting pipeline, and reseal the extraction port with the second sealing element.

[0042] Step 4: Filtrate discharge Open the drain outlet and pour out the water that has been filtered to the bottom of the wide-mouthed bottle. Then reseal the drain outlet. Weigh the entire wide-mouthed bottle at this point and record the weight. =551.98 g.

[0043] Step 5: Low-temperature inert airflow drying Place the drained apparatus in a water bath at 30°C. Connect the outlet to a gas washing bottle containing a 5 wt.% sodium hypochlorite solution and set the argon flow rate to 100 mL / min. Weigh intermittently until constant weight is achieved and record the result. =547.87 g. Total drying time was 6.5 h.

[0044] Step 6: Solid content calculation =1- =0.4520 0.4520 × 100% = 45.20% Solid content in mud phosphorus: 45.20%. Example 3

[0045] Step 1: Equipment preparation and weighing of empty equipment Assemble the basic structure of the device using the same method as in Example 1, weigh the wide-mouth bottle and its internal components, and record the mass of the empty device. =537.24 g. At this time, the vacuum pump and connecting pipelines have not yet been installed.

[0046] Step 2: Sample injection and establishment of inert atmosphere Stir the settled mud-phosphorus sample thoroughly with a stirring rod, take a sample into a beaker, and weigh the sample. =31.34 g, and then the sample was transferred to a quartz funnel. The drain outlet was sealed with the first sealing element, and argon was used as the carrier gas to purge the inside of the device at a flow rate of 200 mL / min for 5 min.

[0047] Step 3: Install the filtration assembly and perform vacuum filtration. Remove the second seal from the extraction port and install the vacuum pump, safety bottle, and connecting tubing. Adjust the argon flow rate to 100 mL / min, turn on the vacuum pump, and perform filtration for 30 minutes.

[0048] After filtration is completed, turn off the vacuum pump, balance the negative pressure, remove the vacuum pump and connecting pipeline, and reseal the extraction port with the second sealing element.

[0049] Step 4: Filtrate discharge Open the drain outlet and pour out the water that has been filtered to the bottom of the wide-mouthed bottle. Then reseal the drain outlet. Weigh the entire wide-mouthed bottle at this point and record the weight. 2 = 556.98 g.

[0050] Step 5: Low-temperature inert airflow drying Place the drained apparatus in a water bath at 50°C. Connect the outlet to a gas washing bottle containing a 5 wt.% sodium hypochlorite solution and set the argon flow rate to 100 mL / min. Weigh intermittently until constant weight is achieved and record the result. =550.24 g. Total drying time was 4.6 h.

[0051] Step 6: Solid content calculation =1- =0.4148 0.4148 × 100% = 41.48% Solid content in mud phosphorus: 41.48%.

[0052] Comparative Example 1 (without vacuum filtration) Step 1: Equipment preparation and weighing of empty equipment Assemble the basic structure of the device using the same method as in Example 1, weigh the wide-mouth bottle and its internal components, and record the mass of the empty device. =537.22 g.

[0053] Step 2: Sample injection and establishment of inert atmosphere Stir the settled mud-phosphorus sample thoroughly with a stirring rod, take a sample into a beaker, and weigh the sample. =20.47 g, and then the sample was transferred to a quartz funnel. The drain outlet was sealed with the first sealing element, and argon was used as the carrier gas to purge the inside of the device at a flow rate of 200 mL / min for 5 min.

[0054] Step 3: Natural filtration (without installing a vacuum pump) After 5 minutes, close the valve, do not install the vacuum pump or connecting pipeline, keep the air extraction port sealed with the second seal, and let the mud phosphorus sample filter naturally by gravity for 30 minutes.

[0055] Step 4: Filtrate discharge Open the drain outlet and pour out the water that has filtered to the bottom of the wide-mouthed bottle. Then reseal the drain outlet. Weigh the entire wide-mouthed bottle at this point and record the weight. 2 = 551.28 g.

[0056] Step 5: Low-temperature inert airflow drying Place the drained apparatus in a water bath at 35°C. Connect the outlet to a gas washing bottle containing a 5 wt.% sodium hypochlorite solution and set the argon flow rate to 100 mL / min. Weigh intermittently until constant weight is achieved and record the result. 3 = 546.05 g. Total drying time is 8.2 h.

[0057] Step 6: Solid content calculation =1- =0.4317 0.4317 × 100% = 43.17% Solid content in mud phosphorus: 43.17%.

[0058] Comparative Example 2 (High-Temperature Drying) Step 1: Equipment preparation and weighing of empty equipment Assemble the basic structure of the device using the same method as in Example 1, weigh the wide-mouth bottle and its internal components, and record the mass of the empty device. =537.19 g.

[0059] Step 2: Sample injection and establishment of inert atmosphere Stir the settled mud-phosphorus sample thoroughly with a stirring rod, take a sample into a beaker, and weigh the sample. =24.72 g, and then the sample was transferred to a quartz funnel. The drain outlet was sealed with the first sealing element, and argon was used as the carrier gas to purge the inside of the device at a flow rate of 200 mL / min for 5 min.

[0060] Step 3: Install the filtration assembly and perform vacuum filtration. Remove the second seal from the extraction port and install the vacuum pump, safety bottle, and connecting tubing. Adjust the argon flow rate to 100 mL / min, turn on the vacuum pump, and perform filtration for 30 minutes.

[0061] After filtration is completed, turn off the vacuum pump, balance the negative pressure, remove the vacuum pump and connecting pipeline, and reseal the extraction port with the second sealing element.

[0062] Step 4: Filtrate discharge Open the drain outlet and pour out the water that has been filtered to the bottom of the wide-mouthed bottle. Then reseal the drain outlet. Weigh the entire wide-mouthed bottle at this point and record the weight. 2 = 551.28 g.

[0063] Step 5: High-temperature drying Place the drained apparatus in a water bath at 100°C. Connect the outlet to a gas washing bottle containing a 5 wt.% sodium hypochlorite solution and set the argon flow rate to 100 mL / min. Weigh intermittently until constant weight is achieved and record the result. 3 = 547.17 g. Total drying time is 2.2 h.

[0064] Step 6: Solid content calculation =1- =0.4037 0.4037 × 100% = 40.37% Solid content in mud phosphorus: 40.37%.

[0065] Analysis and comparison I. Improvement of final results by vacuum filtration Comparative Example 1 (vacuum filtration + 35°C drying) and Comparative Example 1 (no vacuum filtration, only gravity filtration + 35°C drying) Table 1: The above indicates that vacuum filtration can effectively remove most of the free water in mud phosphorus, significantly reduce the drying load, thereby greatly shortening the subsequent drying time and improving the measurement efficiency.

[0066] II. The effect of low-temperature drying on the control of yellow phosphorus volatilization Comparative Example 1 (vacuum filtration + drying at 35°C) and Comparative Example 2 (vacuum filtration + drying at 100°C) Table 2: The above indicates that high-temperature drying leads to significant volatilization of yellow phosphorus in mud phosphorus, resulting in a systematically low solid content measurement value. The low-temperature drying method of 30–50℃ used in this invention effectively inhibits yellow phosphorus volatilization and ensures the accuracy of the measurement results.

[0067] Note: Yellow phosphorus has a melting point of 44.1℃. Even at 35℃, it remains in a solid state, exhibiting extremely low saturated vapor pressure and a very slow volatilization rate. During the several-hour drying process, the mass of yellow phosphorus lost through volatilization accounts for a negligible proportion of the total solid mass.

[0068] III. Exhaust Gas Treatment Effect In all embodiments and comparative examples, the gas outlet was connected to a gas washing bottle containing a 5 wt.% sodium hypochlorite solution. Testing showed that the trace amounts of yellow phosphorus volatilized during the drying process were completely oxidized to non-toxic phosphate by sodium hypochlorite, and the exhaust emissions met environmental protection requirements.

[0069] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for determining the solid content in mud phosphorus, characterized in that, Includes the following steps: S1. Apparatus preparation: Remove the cap of the wide-mouth bottle, fold the filter paper and place it in the quartz funnel, tighten the cap, and weigh the wide-mouth bottle and its internal components used to determine the solid content in mud phosphorus. Record the mass M of the empty apparatus. S2. Establishment of inert atmosphere and sample injection: Inert gas is introduced into the apparatus to replace the air, and the mass of the sample is measured. The mud phosphorus sample was placed in a quartz funnel; S3. Vacuum filtration: Under the protection of inert gas, the vacuum pump is turned on to evacuate the filtrate chamber, so that the liquid components in the mud phosphorus sample pass through the quartz sand layer and enter the filtrate chamber, while the solids are retained in the quartz funnel. S4. Filtrate discharge, filtration ends, restore the device to normal pressure, and discharge the liquid in the filtrate chamber; S5. Low-temperature inert gas drying: Place the apparatus in a constant temperature environment of 30–50°C and continuously introduce inert gas into the apparatus until the total mass of the apparatus and the retained solid reaches a constant weight, denoted as S5. ; S6. Calculate according to the following formula. Calculate the solid content of mud phosphorus.

2. The method according to claim 1, characterized in that: In step S3, the inert gas is argon, and during the filtration process, argon is introduced into the device at a flow rate of 50–300 mL / min.

3. The method according to claim 1, characterized in that: In step S5, the inert gas is argon, the argon flow rate during the drying process is 50-150 mL / min, and the constant temperature environment is provided by a water bath.

4. The method according to claim 1, characterized in that: In step S5, the criterion for determining constant weight is that the absolute value of the difference between two consecutive weighings at a time interval of 20 minutes is not greater than 0.1 g.

5. The method according to claim 1, characterized in that: In step S3, the filtration time is 20 to 90 minutes.

6. The method according to claim 1, characterized in that: In step S5, the exhaust gas is treated with sodium hypochlorite at a concentration of 3-10 wt.%.

7. An apparatus for use in the method according to any one of claims 1 to 6, characterized in that: The bottle includes a wide-mouth bottle, the bottle cap of which is provided with an air inlet and an air outlet with valves, the bottle cap is connected to the air inlet pipe and the air outlet pipe by a leak-proof sealing ring, and the bottom of the bottle body of the wide-mouth bottle is provided with a drain outlet with a first sealing element. A quartz funnel is fixed inside the wide-mouth bottle by a breathable quartz sand layer, and the quartz sand layer and the quartz funnel are sintered together. A filtration chamber is formed between the bottom of the quartz funnel and the bottom of the wide-mouth bottle. The air extraction port is located on the wall of the wide-mouth bottle and communicates with the filtrate chamber. The air extraction port also has a removable second seal.

8. The apparatus according to claim 7, characterized in that: The permeable quartz sand layer has a particle size range of 50–200 mesh and a layer thickness of 8–12 mm.

9. The apparatus according to claim 7, characterized in that: The air extraction port is detachably connected to one end of the pipe, and the other end of the pipe is connected to the vacuum pump via an anti-backflow device; the anti-backflow device is one of a safety bottle, a buffer bottle, and a check valve.

10. The apparatus according to claim 7, characterized in that: It also includes a water bath, in which the wide-mouth bottle is placed; the gas outlet pipe is connected to the gas washing bottle.

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