CN113816348A - Low-temperature solid-liquid separation method for phosphorus sludge and medicament formula - Google Patents

Abstract

The invention discloses a low-temperature solid-liquid separation method for sludge phosphorus, namely a formula, wherein the separation method comprises a dissolving process, a low-temperature solid-liquid separation process, a rectification process and a final product refining, rinsing, storing and packaging process.

Description

Low-temperature solid-liquid separation method for phosphorus sludge and medicament formula

Technical Field

The invention relates to the technical field of sludge phosphorus solid-liquid separation, in particular to a low-temperature solid-liquid separation method for sludge phosphorus and a medicament formula.

Background

The sludge phosphorus is one of main byproducts generated in the production process of the yellow phosphorus, belongs to dangerous solid wastes in the phosphorus chemical industry, and the treatment and utilization of the sludge phosphorus are very important problems in the production of the yellow phosphorus, which not only affect the recovery rate and the production cost of the phosphorus in the industrial production of the yellow phosphorus, but also cause serious environmental pollution problems, so that almost all domestic yellow phosphorus manufacturers discuss the treatment and utilization of the sludge phosphorus to achieve good environmental, economic and social benefits, thereby realizing the strategic and strategic development of human sustainable development.

However, in the actual use process, the solid-liquid separation process of the sludge phosphorus is not mature, so that an environment-friendly separation technology with low cost is urgently needed.

Disclosure of Invention

The invention aims to provide a low-temperature solid-liquid separation method for sludge phosphorus and a medicament formula, so as to overcome the defects of the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

a low-temperature solid-liquid separation method for sludge phosphorus comprises a dissolving process, a low-temperature solid-liquid separation process, a rectification process, and refining, rinsing, storing and packaging of a final product.

As a further scheme of the invention: the dissolving process comprises the steps of injecting cold sewage into a dissolving tank; after the phosphorous sludge in the storage tank is heated and dissolved by hot water or steam, a submerged pump is used for pumping the phosphorous sludge to a dissolving tank, the material pumped into the dissolving tank is kept stand for 25-40min by utilizing the specific gravity difference characteristic of the material, the phosphorous is completely settled at the bottom of the dissolving tank, the water is positioned at the upper part of the dissolving tank, the phosphorous sludge is isolated from the air, the spontaneous combustion phenomenon of the yellow phosphorous is avoided, a cold sewage circulating pump is started to operate, the cold sewage pump is sent into the dissolving tank to replace hot water for cooling, the replaced hot water overflows to a cold sewage pool from a top filling overflow port, and the temperature is circularly cooled until the temperature of the dissolving tank is reduced to 20-28 ℃.

As a further scheme of the invention: : and after the temperature of the dissolving tank is reduced to 20-28 ℃, opening a valve from a nitrogen making machine, performing air replacement on the dissolving tank until the oxygen content is less than or equal to 0.2%, slowly opening a bottom valve of an extractant collector, injecting an extractant into the dissolving tank and mixing the extractant with the phosphorus sludge, starting a stirrer to uniformly mix the mixed solution, and standing for 150min to ensure that the extractant is fully mixed with the phosphorus sludge.

As a further scheme of the invention: : in the low-temperature solid-liquid separation process, suspension liquid formed by mixing and dissolving an extracting agent and phosphorus sludge is fed into a centrifuge, whether filter cloth of the centrifuge is flat or not is checked before feeding, and then a cover of the centrifuge is covered; opening a nitrogen valve, carrying out nitrogen replacement on the interior of the centrifuge cavity and the rear end of a feed delivery pipe valve until the oxygen content is less than or equal to 0.2%, opening a water spraying valve, enabling flowing water to flow in along the inner wall, and enabling a spray head arranged in the centrifuge cavity to spray in an atomized manner after the valve is opened; in order to avoid static electricity generated by friction, the static electricity is grounded, after the centrifuge is started to normally run in an idle state, a manual valve of a discharge valve of a dissolving tank is opened, when the oxygen content is less than or equal to 0.2%, a chain automatic valve is automatically opened, materials automatically flow into a centrifuge cavity from a material conveying pipe of the dissolving tank for centrifugal separation, filtrate automatically flows into a heater through a U-shaped liquid seal device, and a filter screen is cleaned by clean water.

As a further scheme of the invention: : after the filter screen is cleaned, feeding for the second time, before feeding for the second time, opening an automatic emptying valve of an inlet pipe of the centrifugal machine, slightly filling nitrogen into the cavity of the centrifugal machine for replacement until the oxygen content is less than or equal to 0.2%, filling water into the cavity of the centrifugal machine, opening the centrifugal machine, checking whether the filter cloth of the centrifugal machine is flat or replacing the filter cloth, and then covering a cover of the centrifugal machine; opening a nitrogen valve, carrying out nitrogen replacement on the interior of a centrifuge cavity and the rear end of a material conveying pipe valve until the oxygen content is less than or equal to 0.2%, opening a water spraying valve, opening a spray head arranged in the centrifuge cavity after the valve is opened to enable the interior of the centrifuge cavity to be in atomized spray, starting the centrifuge to normally operate in a no-load state, opening a manual valve of a discharge valve of a dissolving tank, automatically opening a linked automatic valve when the oxygen content is less than or equal to 0.2%, automatically flowing materials into the centrifuge cavity from a material conveying pipe of the dissolving tank for centrifugal separation, and automatically flowing filtrate into a heater through a U-shaped liquid seal device.

As a further scheme of the invention: : the rectification process refers to the preparation work of a heater before the centrifugal machine is started; firstly, 30-40cm of clean water is injected into a heater, and then nitrogen from a nitrogen making machine is used for replacing the heater; until the oxygen content is less than or equal to 0.2%, the material from the centrifuge automatically flows into the heater by utilizing the height difference, after the material flows out, the centrifuge is stopped, the self-regulating valve at the outlet of the centrifuge is remotely closed, the water inlet self-control valve of the centrifuge is opened through remote control, the centrifuge is immediately filled with water, and the phenomenon that mixed gas explosion occurs when a centrifuge cover is opened when residual medicament in the centrifuge is continuously volatilized to clean filter cakes of the centrifuge is ensured.

After the centrifuge cavity is filled with water, slowly opening a nitrogen valve from a nitrogen making machine, slightly filling nitrogen into a heater, then opening a steam valve from a boiler, heating materials in the heater by steam through a steam coil pipe, continuously gasifying and volatilizing an extractant in the materials due to temperature rise to escape from the water surface, entering a condenser, continuously liquefying the gasified and volatilized extractant to form a liquid after entering the condenser, automatically flowing to a recovery tank with water, and storing and recycling; the pressure of the system is exhausted through a breather valve at the top of the recovery tank, after all the extractant is volatilized, the distillation residue in the heater is the yellow phosphorus and water, the product is remotely controlled through a remote control valve, a valve at the bottom of the heater is opened, the product automatically flows into a liquid seal tank and is sent to a refining process through a pump for refining, and the refined qualified product is packaged and sold.

Compared with the prior art, the invention has the beneficial effects that: in the process of processing and recovering the products, the invention uses the physical properties of the materials in the whole process, does not generate other products such as chemical reaction in the process, basically realizes full-sealing operation in operation, has no pollution on site, is the most ideal process for solving the phosphorus mud treatment process in the yellow phosphorus industry, has short supply after technical breakthrough and market shortage, and has huge potential and greater profitability for leading the market.

Drawings

FIG. 1 is a schematic flow diagram of the dissolution process of the present invention;

FIG. 2 is a schematic flow diagram of a low temperature solid-liquid process of the present invention;

FIG. 3 is a block diagram of a process flow of a rectification process of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-3, the present invention provides a technical solution:

by utilizing the property that yellow phosphorus is easy to dissolve in carbon disulfide (solvent), the yellow phosphorus is subjected to the process operations of dissolving, filtering, distilling and the like in the experimental process, and a plurality of tests show that more ideal data are obtained, and then the yellow phosphorus is subjected to the operation of a pilot plant (the used equipment at that time is the pilot plant development tests of an enamel stirred tank, a centrifugal machine, a reboiler, a condenser, a recoverer and the like), so that the process is very smooth, the recovery rate of the solvent reaches 70%, the mass purity content of the product reaches 99.5% (the qualified product is 99.95%) and the product can reach the qualified product after being treated by a refining process.

At present, a plurality of patents are provided on the technical network, but an industrial production device is not yet published, in recent years, due to the strict regulation of the state on the emission behavior of environmental protection pollutants, the coming policy is intensified year by year, the advanced process for treating the phosphorus mud which is a byproduct in the yellow phosphorus industry is in the forefront, however, in the process of processing and recovering products, the method uses the physical properties of materials in the whole course, the process does not generate other products such as chemical reaction and the like, the full-sealing operation is basically realized in the operation, no pollution is caused on the site, the method is the most ideal process for solving the phosphorus mud treatment process in the yellow phosphorus industry, after the technology breaks through, the market supply is not in demand, and the method has huge potential for leading the market and larger profitability.

In the embodiment, a low-temperature solid-liquid separation method for phosphorus sludge is characterized in that the physical characteristics of 10R, boiling point and large density difference of yellow phosphorus in carbon disulfide are utilized, solid-phase yellow phosphorus in phosphorus sludge is rapidly dissolved at low temperature, the yellow phosphorus in phosphorus sludge is dissolved and enters a liquid phase and is deposited at the bottom of a container, solid-phase dust is suspended in a liquid seal middle layer, after standing and layering, a phosphorus-containing solution is conveyed to a rectification process through centrifugal separation equipment for rectification, and carbon disulfide with a low boiling point continuously overflows from the top of a tower through heating and enters a condensation recovery system for recycling;

in the rectification process, carbon disulfide has a low boiling point and rapidly escapes from the liquid level, the R value is continuously reduced, yellow phosphorus is continuously separated out along with the change of the reduced R value, and finally, after the rectification of the carbon disulfide is finished, the materials left by the rectification equipment are the yellow phosphorus and water, and the yellow phosphorus is further refined and rinsed by the conveying equipment until the yellow phosphorus is qualified.

The production process comprises the following steps:

fourthly, operation indexes:

serial number	Index name	Operating range	Unit of	Remarks for note
					1	System pressure	0.3	kPa
2	Temperature of extraction	≤20	Degree of rotation
					3	Temperature of rectification	150	Degree of rotation
4	O2％	≤0.5	％
					5	Product content	≥99.9	％
6	Phosphorus content of residue	≤6	％

The main production device of the device comprises a dissolving process, a low-temperature solid-liquid separation process, a rectification process, and refining, rinsing, storing and packaging of a final product.

The following process flow is described according to the working procedures:

first, dissolving process flow block diagram

1. The process flow diagram of the dissolution process is shown in figure 1 below:

2. summary of the Process flow for the dissolution procedure

First, 1m of cold waste water was poured into a dissolution tank (stirred tank). After the phosphorus sludge in the storage tank is heated and dissolved by hot water or steam, a submerged pump is used for pumping the phosphorus sludge into a dissolving tank (the existing dissolving tank), the material pumped into the dissolving tank is kept still for 30min by utilizing the characteristic of material specific gravity difference, the phosphorus sludge after the keeping still has large specific gravity (1.5g/m3), the specific gravity of water (1g/m3) is that the phosphorus sludge is completely settled at the bottom of the dissolving tank, water is positioned at the upper part of the dissolving tank and is isolated from the air, the spontaneous combustion phenomenon of yellow phosphorus is avoided, a cold sewage circulating pump is started to operate, the cold sewage pump is sent into the dissolving tank to replace hot water for cooling, the replaced hot water overflows to a cold sewage pool from a top filling overflow port, and the temperature is lowered circularly until the temperature of the dissolving tank is lowered to 25 ℃.

When the temperature of the dissolving tank is reduced to 25 ℃, a valve from a nitrogen making machine is opened, air replacement is carried out on the dissolving tank until the oxygen content is less than or equal to 0.2 percent, then a bottom valve of an extractant collector is slowly opened, the extractant metered by a liquid level sensor is mixed with the phosphorus sludge into the dissolving tank according to the proportion of 100:11, a stirrer is started to uniformly mix the mixed solution, and the mixture is kept stand for 120min, so that the solvent is fully mixed with the phosphorus sludge.

Second, low-temperature solid-liquid separation process flow block diagram

1. The process flow block schematic diagram of the low-temperature solid-liquid separation process 2:

2. overview of the Process flow of Low temperature solid-liquid separation

Before feeding, opening the centrifuge, checking whether the filter cloth of the centrifuge is flat or not, and then covering the centrifuge cover. Opening a nitrogen valve, performing nitrogen replacement on the inner part of a cavity of the centrifuge and the rear end of a valve of a conveying pipe until the oxygen content is less than or equal to 0.2 percent, opening a water spraying valve (flowing in along the inner wall), enabling a spray head arranged in the cavity of the centrifuge to spray in an atomized state (generating static electricity by friction and grounding) after the valve is opened, inputting the frequency of the centrifuge to 25hz, starting a manual valve of a discharge valve of a dissolving tank after the centrifuge is started to normally run in a no-load mode, automatically opening a chain automatic valve when the oxygen content is less than or equal to 0.2 percent, enabling materials to flow into the cavity of the centrifuge from the conveying pipe of the dissolving tank for centrifugal separation, enabling filtrate to flow into a heater through a U-shaped liquid sealer, and cleaning a filter screen through clear water

Before the second feeding, opening an automatic emptying valve of an inlet pipe of the centrifuge, slightly filling nitrogen into the cavity of the centrifuge for replacement until the oxygen content is less than or equal to 0.2%, filling water into the cavity of the centrifuge, opening the centrifuge, checking whether the filter cloth of the centrifuge is flat or replacing the filter cloth, and then covering a cover of the centrifuge. Opening a nitrogen valve, carrying out nitrogen replacement on the interior of a cavity of the centrifuge and the rear end of a valve of a material conveying pipe until the oxygen content is less than or equal to 0.2%, opening a water spraying valve, opening a spray head arranged in the cavity of the centrifuge after the valve is opened to enable the cavity of the centrifuge to be in atomized spray, inputting the frequency of 25hz of the centrifuge, starting the idle normal operation of the centrifuge, opening a manual valve of a discharge valve of a dissolving tank, automatically opening a linked automatic valve when the oxygen content is less than or equal to 0.2%, automatically flowing materials from the material conveying pipe of the dissolving tank into the cavity of the centrifuge for centrifugal separation, and automatically flowing filtrate into a heater through a U-shaped liquid seal device.

Third, the process flow of the rectification process is a block diagram

1. Process flow block schematic diagram of rectification process 3

2. The process flow of the rectification procedure is summarized as follows:

the heater is prepared prior to the centrifuge being started. Firstly, 30-40cm of clear water (buffering and static elimination) is injected into a heater (a water injection pipe), and then nitrogen from a nitrogen making machine is used for replacing the inside of the heater; until the oxygen content is replaced to be less than or equal to 0.2 percent (synchronous replacement with the centrifuge), the material from the centrifuge automatically flows into the heater by utilizing the high potential difference, after the material flows out, the centrifuge is stopped, the self-regulating valve at the outlet of the centrifuge is remotely closed, the water inlet self-control valve of the centrifuge is remotely controlled to be opened, the centrifuge is immediately filled with water, and the phenomenon that when the filter cake of the centrifuge is cleaned, the mixed gas is exploded to hurt people when the centrifuge cover is opened due to continuous volatilization of the residual medicament in the centrifuge is ensured.

After the centrifuge cavity is filled with water, slowly opening a nitrogen valve from a nitrogen making machine, slightly filling nitrogen into a heater, then opening a steam valve from a boiler, raising the temperature of materials in the heater by steam through a steam coil pipe, continuously gasifying and volatilizing an extractant in the materials due to the temperature rise to escape from the water surface, entering a condenser, continuously liquefying the gasified and volatilized extractant after entering the condenser to form a liquid, automatically flowing to a recovery tank with water, and storing and recycling. The pressure of the system is exhausted through a breather valve at the top of the recovery tank, after all the extractant is volatilized, the distillation residue in the heater is the yellow phosphorus and water, the product is remotely controlled through a remote control valve, a valve at the bottom of the heater is opened, the product automatically flows into a liquid seal tank and is sent to a refining process through a pump for refining, and the refined qualified product is packaged and sold.

The following operation is started in the rectification process after the steam is more than or equal to 0.3 Mpa:

1. opening an inlet and outlet valve of the cooler, starting a cooling water pump and ensuring that cooling water circulates normally;

2. slightly opening a nitrogen valve to replace the heater; in the rectification process, the nitrogen valve is kept slightly open and the inside of the heater is kept at positive pressure.

3. Open the drain valve of the steam outlet and the condensed water in the drain pipe, and close the drain valve after draining. Then slowly opening the inlet valve and introducing steam into the heater. When the temperature in the heater reaches 30 ℃, closing the steam inlet valve and keeping the temperature for 40 min; observing and recording the recovery amount of the extracting agent; then slowly opening the steam inlet valve, closing the steam inlet valve after the temperature of the heater reaches 50 ℃, and keeping the temperature for 40 min; observing and recording the recovery amount of the extracting agent; slowly opening the steam inlet valve again, slowly heating to 80 ℃, closing the steam inlet valve, and keeping the temperature for 30 min; observing and recording the recovery amount of the extracting agent; calculating the ratio of the addition amount to the recovery amount of the dissolved phosphorus, sampling the sampling valve at the outlet of the heater after the ratio reaches 70-80%, rinsing the sampling valve with cooling water, and observing the cooling condition of the separated phosphorus.

4. In the process of rectifying the solvent by the heater, the temperature in the heater is well controlled, and the phenomenon that the temperature is too high and the solvent is not recycled is avoided at the initial stage.

5. The condenser temperature in the rectification process is the normal temperature of water (the lower the temperature is, the better the refrigerant can be selected according to the situation), and the pressure is 120-130kpa.

Thirdly, automatically controlling linkage requirements of the system:

1. the pressure of the dissolving tank is more than or equal to 0.1MPa and is linked with the opening of an emptying valve of the dissolving tank;

2. the oxygen content in the centrifuge is less than or equal to 0.2 percent and is linked with the feed valve;

3. the temperature of the heater is interlocked with the self-regulating valve of the steam inlet;

introduction of equipment composition

One, one) dissolving tank

1. The system comprises an on-site thermometer, a pressure gauge, a liquid level meter, a remote transmission temperature, a remote transmission pressure, a remote transmission liquid level meter and an oxygen content analyzer;

2. the automatic emptying valve, the flame arrester on the automatic emptying valve and the emptying pipe are intermittently emptied, and open fire does not exist within the range of more than 3m or 10 m higher than the platform;

3. a solvent adding pipe and a valve, a phosphorus removing pipe and a valve, and a cleaning water pipe and a valve;

4. an outlet of the dissolving tank: a manual valve, an automatic cut-off valve, a sight glass valve and a cleaning water pipe joint;

II) centrifuge

1、≤0.2％；

2. The electrostatic resistance is less than or equal to 1 omega.

III) Heater

1. The remote oxygen analyzer comprises an on-site thermometer, a pressure gauge, a liquid level meter, a remote temperature display, a remote pressure display, a remote liquid level display and a remote oxygen content analyzer;

2. heater outlet pipe: two manual valves, a blowdown valve and a sight glass valve.

The production device is constructed and put into operation:

after the pilot plant test is finished, the team rapidly adjusts the industrial structure through sharp market insights, rapidly enters the industries of chemical engineering, environmental protection and the like on the basis of ensuring that the building and security industry keeps the growth rate, and builds a set of production device in the last year, but because the team has weak professional technical strength and insufficient knowledge on production equipment and process, several safe accidents occur successively in the production process, and the reasons of the accidents always have several points:

1. the produced nitrogen of the purchased nitrogen making unit is unqualified, and the content of the nitrogen making unit is only 86 percent through chromatographic analysis and comparison, so that two times of explosion occur in the centrifugal separation process.

2. The dissolving tank for processing and installation is manufactured by self, unreasonable setting and illegal operation of operators are set, and in the process of re-inspection, under the conditions that nitrogen is not added and water is not added in the dissolving tank for sealing, the operators uncover a water sealing cover of the dissolving tank, so that solvent gas volatilized and accumulated in the tank overflows a tank body, and a flash explosion phenomenon occurs.

The debugging work reveals various reasons of unreasonable equipment type selection, unsafe equipment design, insufficient understanding of operators on solvent properties and harmfulness and the like, and for the reason, the debugging is suspended, a knowledgeable and competent team with experience in operation and equipment in the carbon disulfide industry must be searched for management and operation, and development is conscientiously carried out.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

The invention discloses a low-temperature solid-liquid separation method for sludge phosphorus, namely a formula, wherein the separation method comprises a dissolving process, a low-temperature solid-liquid separation process, a rectification process and a final product refining, rinsing, storing and packaging process.

Claims (6)

1. A low-temperature solid-liquid separation method for sludge phosphorus is characterized by comprising the following steps: the separation method comprises a dissolving process, a low-temperature solid-liquid separation process, a rectification process, and refining, rinsing, storing and packaging of a final product.

2. The low-temperature solid-liquid separation method for the phosphorus sludge according to claim 1, which is characterized in that: the dissolving process comprises the steps of injecting cold sewage into a dissolving tank; after the phosphorous sludge in the storage tank is heated and dissolved by hot water or steam, a submerged pump is used for pumping the phosphorous sludge to a dissolving tank, the material pumped into the dissolving tank is kept stand for 25-40min by utilizing the specific gravity difference characteristic of the material, the phosphorous is completely settled at the bottom of the dissolving tank, the water is positioned at the upper part of the dissolving tank, the phosphorous sludge is isolated from the air, the spontaneous combustion phenomenon of the yellow phosphorous is avoided, a cold sewage circulating pump is started to operate, the cold sewage pump is sent into the dissolving tank to replace hot water for cooling, the replaced hot water overflows to a cold sewage pool from a top filling overflow port, and the temperature is circularly cooled until the temperature of the dissolving tank is reduced to 20-28 ℃.

3. The low-temperature solid-liquid separation method for the phosphorus sludge according to claim 2, characterized in that: and after the temperature of the dissolving tank is reduced to 20-28 ℃, opening a valve from a nitrogen making machine, performing air replacement on the dissolving tank until the oxygen content is less than or equal to 0.2%, slowly opening a bottom valve of an extractant collector, injecting an extractant into the dissolving tank and mixing the extractant with the phosphorus sludge, starting a stirrer to uniformly mix the mixed solution, and standing for 150min to ensure that the extractant is fully mixed with the phosphorus sludge.

4. The low-temperature solid-liquid separation method for the phosphorus sludge according to claim 1, which is characterized in that: in the low-temperature solid-liquid separation process, suspension liquid formed by mixing and dissolving an extracting agent and phosphorus sludge is fed into a centrifuge, whether filter cloth of the centrifuge is flat or not is checked before feeding, and then a cover of the centrifuge is covered; opening a nitrogen valve, carrying out nitrogen replacement on the interior of the centrifuge cavity and the rear end of a feed delivery pipe valve until the oxygen content is less than or equal to 0.2%, opening a water spraying valve, enabling flowing water to flow in along the inner wall, and enabling a spray head arranged in the centrifuge cavity to spray in an atomized manner after the valve is opened; in order to avoid static electricity generated by friction, the static electricity is grounded, after the centrifuge is started to normally run in an idle state, a manual valve of a discharge valve of a dissolving tank is opened, when the oxygen content is less than or equal to 0.2%, a chain automatic valve is automatically opened, materials automatically flow into a centrifuge cavity from a material conveying pipe of the dissolving tank for centrifugal separation, filtrate automatically flows into a heater through a U-shaped liquid seal device, and a filter screen is cleaned by clean water.

5. The low-temperature solid-liquid separation method for the phosphorus sludge according to claim 4, characterized in that: after the filter screen is cleaned, feeding for the second time, before feeding for the second time, opening an automatic emptying valve of an inlet pipe of the centrifugal machine, slightly filling nitrogen into the cavity of the centrifugal machine for replacement until the oxygen content is less than or equal to 0.2%, filling water into the cavity of the centrifugal machine, opening the centrifugal machine, checking whether the filter cloth of the centrifugal machine is flat or replacing the filter cloth, and then covering a cover of the centrifugal machine; opening a nitrogen valve, carrying out nitrogen replacement on the interior of a centrifuge cavity and the rear end of a material conveying pipe valve until the oxygen content is less than or equal to 0.2%, opening a water spraying valve, opening a spray head arranged in the centrifuge cavity after the valve is opened to enable the interior of the centrifuge cavity to be in atomized spray, starting the centrifuge to normally operate in a no-load state, opening a manual valve of a discharge valve of a dissolving tank, automatically opening a linked automatic valve when the oxygen content is less than or equal to 0.2%, automatically flowing materials into the centrifuge cavity from a material conveying pipe of the dissolving tank for centrifugal separation, and automatically flowing filtrate into a heater through a U-shaped liquid seal device.

6. The low-temperature solid-liquid separation method for the phosphorus sludge according to claim 1, which is characterized in that: the rectification process refers to the preparation work of a heater before the centrifugal machine is started; firstly, 30-40cm of clean water is injected into a heater, and then nitrogen from a nitrogen making machine is used for replacing the heater; until the oxygen content is less than or equal to 0.2%, the material from the centrifuge automatically flows into the heater by utilizing the height difference, after the material flows out, the centrifuge is stopped, the self-regulating valve at the outlet of the centrifuge is remotely closed, the water inlet self-control valve of the centrifuge is opened through remote control, the centrifuge is immediately filled with water, and the phenomenon that mixed gas explosion occurs when a centrifuge cover is opened when residual medicament in the centrifuge is continuously volatilized to clean filter cakes of the centrifuge is ensured.

After the centrifuge cavity is filled with water, slowly opening a nitrogen valve from a nitrogen making machine, slightly filling nitrogen into a heater, then opening a steam valve from a boiler, heating materials in the heater by steam through a steam coil pipe, continuously gasifying and volatilizing an extractant in the materials due to temperature rise to escape from the water surface, entering a condenser, continuously liquefying the gasified and volatilized extractant to form a liquid after entering the condenser, automatically flowing to a recovery tank with water, and storing and recycling; the pressure of the system is exhausted through a breather valve at the top of the recovery tank, after all the extractant is volatilized, the distillation residue in the heater is the yellow phosphorus and water, the product is remotely controlled through a remote control valve, a valve at the bottom of the heater is opened, the product automatically flows into a liquid seal tank and is sent to a refining process through a pump for refining, and the refined qualified product is packaged and sold.

Images