A production method and system for preparing sodium phosphate by using phosphorus-containing waste gas

Abstract

The present application belongs to the field of yellow phosphorus tail gas, and particularly relates to a production method for preparing phosphate by using yellow phosphorus tail gas. The method comprises the following steps: S1, preparing yellow phosphorus tail gas and generating phosphorus-containing waste gas during the preparation process of the yellow phosphorus tail gas; S2, reacting the prepared yellow phosphorus tail gas with a stripping agent to generate waste lye containing sodium sulfide, sodium carbonate and sodium phosphate; S3, adding an oxidizing agent into the waste lye, and reacting the sodium sulfide in the waste lye with the oxidizing agent to generate elemental sulfur and sodium hydroxide; S4, removing the elemental sulfur in the waste lye, and leaving sodium carbonate, sodium phosphate and sodium hydroxide in the waste lye; and S5, adding the phosphorus-containing waste gas into the waste lye, and reacting the phosphorus-containing waste gas with water to generate phosphoric acid, and reacting the phosphoric acid with sodium carbonate and sodium hydroxide to generate sodium phosphate. The present application provides a production method for preparing phosphate by using yellow phosphorus tail gas, and aims to solve the problems of complicated preparation process and high cost of the prior art.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of yellow phosphorus tail gas, and particularly relates to a production method and system for preparing sodium phosphate by using phosphorus-containing waste gas. BACKGROUND

[0002] Yellow phosphorus tail gas is a kind of waste gas, which has certain pollution to the environment. Therefore, in order to avoid the pollution of yellow phosphorus tail gas to the environment, the yellow phosphorus tail gas is often used as a raw material to prepare formate, so as to realize the treatment of the yellow phosphorus tail gas. Meanwhile, the formate prepared by the yellow phosphorus tail gas also has certain economic value, which is beneficial to improving the economic benefits.

[0003] However, in the process of preparing formate by using the yellow phosphorus tail gas in the prior art, a transition product sodium sulfide is generated. In order to remove the generated transition product sodium sulfide, the following steps are usually included: first, an acid substance is used to react with the sodium sulfide to generate hydrogen sulfide; second, the hydrogen sulfide is subjected to oxidation combustion to generate sulfur dioxide; and third, the sodium sulfide is generated by reacting the lye with the sulfur dioxide. The above steps are relatively complicated, and thus the steps of the whole preparation process of the phosphate are relatively complicated, and the cost is relatively high. SUMMARY

[0004] The application provides a production method for preparing a phosphate by using a yellow phosphorus tail gas, and aims to solve the problems of complicated steps and high cost in the preparation process of the phosphate in the prior art.

[0005] In order to achieve the above-mentioned purpose, the application provides a production method for preparing sodium phosphate by using phosphorus-containing waste gas, which includes the following steps

[0006] S1, preparing a yellow phosphorus tail gas, and generating phosphorus-containing waste gas in the preparation process of the yellow phosphorus tail gas;

[0007] S2, reacting the prepared yellow phosphorus tail gas with a stripping agent to generate waste lye, and the waste lye containing sodium sulfide, sodium carbonate and sodium phosphate;

[0008] S3, adding an oxidizing agent into the waste lye, and reacting the sodium sulfide in the waste lye with the oxidizing agent to generate elemental sulfur and sodium hydroxide;

[0009] S4, removing the elemental sulfur in the waste lye, and the waste lye remaining with sodium carbonate, sodium phosphate and sodium hydroxide;

[0010] S5, adding the phosphorus-containing waste gas into the waste lye, and generating phosphoric acid by the phosphorus-containing waste gas and water, and reacting the phosphoric acid with the sodium carbonate and the sodium hydroxide to generate sodium phosphate.

[0011] The scheme discloses a production method for preparing a phosphate, which only needs to use an oxidizing agent to react with sodium sulfide to generate elemental sulfur when a transition product sodium sulfide is treated, and then the elemental sulfur is filtered.

[0012] Preferably, in order to improve the reaction efficiency of the stripping agent and the yellow phosphorus tail gas, the stripping agent is sprayed to be in contact with the yellow phosphorus tail gas in S2 to generate waste lye through reaction.

[0013] Alternatively, in order to improve the reaction efficiency of the stripping agent and the yellow phosphorus tail gas, the yellow phosphorus tail gas is injected into the stripping agent in S2 to generate waste lye through reaction.

[0014] Preferably, in order to ensure that the sodium sulfide can be fully reacted with the oxidizing agent, the total amount of the oxidizing agent and the total amount of the waste lye are in a ratio of 0.25:1 in S3.

[0015] Preferably, in order to avoid waste of the oxidizing agent, the content of the sodium sulfide in the waste lye is detected in S3, and when the content of the sodium sulfide is lower than a threshold value, the addition of the oxidizing agent is stopped. When the content of the sodium sulfide is detected to be lower than the threshold value, it is indicated that the sodium sulfide has been fully reacted. Therefore, the addition of the oxidizing agent is stopped at this time, so as to avoid waste of the oxidizing agent due to excessive addition of the oxidizing agent.

[0016] Preferably, in order to realize the reaction with sodium oxide and avoid generation of a by-product which is difficult to handle, the oxidizing agent is hydrogen peroxide in S3. When the oxidizing agent reacts with the sodium sulfide, no by-product which is difficult to handle is generated.

[0017] Preferably, in order to remove the elemental sulfur, the elemental sulfur in the waste lye is removed through filtration in S4. The removal effect of the elemental sulfur is better through the filtration.

[0018] Preferably, in order to ensure that the reaction of the phosphorus-containing waste gas is complete and avoid leakage of residual phosphorus-containing waste gas, the concentration of sodium carbonate and / or sodium hydroxide is detected in S5, and when the concentration of the sodium carbonate and / or the sodium hydroxide is lower than a threshold value, the addition of the phosphorus-containing waste gas into the waste lye is stopped.

[0019] Preferably, in order to ensure that the reaction of the phosphorus-containing waste gas is complete and avoid leakage of residual phosphorus-containing waste gas, the PH value of the waste lye is detected in S5, and when the PH value is in a predetermined range, the addition of the phosphorus-containing waste gas into the waste lye is stopped.

[0020] The second aspect of the present application discloses a production system using the above production method, which comprises

[0021] a reaction chamber;

[0022] a tail gas supply module in communication with the reaction chamber, the tail gas supply module configured to release a yellow phosphorus tail gas into the reaction chamber;

[0023] a stripping agent release module in communication with the reaction chamber, the stripping agent release module configured to release a stripping agent into the reaction chamber;

[0024] an oxidizing agent release module in communication with the reaction chamber, the oxidizing agent release module configured to add an oxidizing agent into the reaction chamber; and

[0025] a phosphorus-containing waste gas release module in communication with the reaction chamber, the phosphorus-containing waste gas release module configured to release a phosphorus-containing waste gas.

[0026] In the present solution, the reaction chamber is used to carry out the reaction, the tail gas supply module supplies the yellow phosphorus tail gas into the reaction chamber, and the stripping agent release module releases the stripping agent into the reaction chamber. The yellow phosphorus tail gas and the stripping agent react to generate waste lye. Then, the oxidizing agent release module can add the oxidizing agent into the reaction chamber, and the oxidizing agent reacts with the sodium sulfide to generate elemental sulfur and sodium hydroxide. Finally, the phosphorus-containing waste gas release module adds the phosphorus-containing waste gas into the reaction chamber, the phosphorus-containing waste gas reacts with water to generate phosphoric acid, and the phosphoric acid reacts with sodium carbonate and sodium hydroxide to generate sodium phosphate.

[0027] Preferably, in order to avoid excessive addition of the oxidizing agent, the present solution further comprises a first detection module, which is arranged in the reaction chamber and is configured to detect the content of sodium sulfide. The first detection module is configured to detect the content of sodium sulfide, and when the content of sodium sulfide is too low, the addition of the oxidizing agent is stopped.

[0028] In order to avoid excessive addition of the phosphorus-containing waste gas, the present solution further comprises a second detection module, which is arranged in the reaction chamber and is configured to detect the content of sodium carbonate and / or sodium hydroxide. The content of sodium carbonate and / or sodium hydroxide is detected, and when the content of sodium carbonate and / or sodium hydroxide is lower than a threshold value, the addition of the phosphorus-containing waste gas is stopped to avoid excessive addition of the phosphorus-containing waste gas.

[0029] The present solution has the following advantages: first, when the intermediate product sodium sulfide is treated, only the oxidizing agent is used to react with the sodium sulfide to generate elemental sulfur, and then the elemental sulfur is filtered, so that the steps are simple and the cost is low.

[0030] Second, the oxidizing agent and the sodium sulfide also generate sodium hydroxide, and the sodium hydroxide can generate sodium phosphate in the subsequent reaction, which further improves the yield of sodium phosphate.

[0031] Thirdly, the phosphorus-containing waste gas in the production process of yellow phosphorus tail gas is used in the preparation process of sodium phosphate, the phosphorus-containing waste gas is effectively utilized, the phosphorus-containing waste gas is avoided from polluting the environment, and the utilization rate of the phosphorus-containing waste gas is improved. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A flow chart of a production method for preparing a phosphate salt by using yellow phosphorus tail gas in Example 1.

[0033] Figure 2 A schematic diagram of a reaction chamber in Example 7

[0034] Figure 3 A schematic diagram of a reaction chamber in Example 8.

[0035] BRIEF DESCRIPTION OF DRAWINGS: Reaction chamber 1, connecting pipe 2, delivery pump 3, atomizing nozzle 4, filter 5, observation part 6, phosphorus-containing waste gas release module 7, cleaning pump 8. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments clearer and more apparent, the present application will be further described in detail below in combination with the drawings and embodiments. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments are not meant to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0037] In the present disclosure, the orientation words such as "inner" and "outer" are defined according to the contour of the corresponding parts themselves unless otherwise stated. The terms such as "first", "second" and the like used in the present disclosure are used to distinguish one element from another element, and do not have sequentiality and importance.

[0038] Example 1

[0039] Basically as shown in the accompanying Figure 1 A production method for preparing a phosphate salt by using yellow phosphorus tail gas, comprising the following steps

[0040] S1, preparing yellow phosphorus tail gas, in which phosphorus-containing waste gas is generated in the preparation process of yellow phosphorus tail gas. The main component in the phosphorus-containing waste gas is phosphorus pentoxide gas. The process of preparing yellow phosphorus tail gas can refer to the prior art. The prepared phosphorus-containing waste gas is temporarily stored, and the phosphorus-containing waste gas is not discharged to avoid environmental pollution caused by leakage of the phosphorus-containing waste gas.

[0041] S2, releasing the stripping agent to react with the phosphorus tail gas, the stripping agent is preferably sodium hydroxide solution. The phosphorus tail gas reacts with the stripping agent to generate waste lye, the generated waste lye contains sodium sulfide, sodium carbonate and sodium phosphate. The released stripping agent is in mist form to improve the reaction rate of the stripping agent with the phosphorus tail gas.

[0042] S3, adding hydrogen peroxide to the waste lye, the sodium sulfide in the waste lye reacts to generate elemental sulfur and sodium hydroxide. The chemical formula of the reaction between sodium sulfide and hydrogen peroxide is: 2Na2S+2H2O2-→2S+4NaOH. The total amount of hydrogen peroxide added is 0.25 times the total amount of waste lye.

[0043] S4, filtering to remove the elemental sulfur in the waste lye, the elemental sulfur is in solid form. In order to achieve better removal effect of the elemental sulfur, at least two times of filtration can be performed to remove the elemental sulfur. After filtering the elemental sulfur, the waste lye remains sodium carbonate, sodium phosphate and sodium hydroxide.

[0044] In order to determine the removal effect of the elemental sulfur, visual detection method is used for detection. The visual detection method is to observe the turbidity of the waste lye by visual observation. When the removal effect of the elemental sulfur is better, the turbidity of the waste lye is lower. When the waste lye contains more elemental sulfur, the turbidity of the waste lye is higher. The detection efficiency is higher by using the visual detection method.

[0045] S5, adding the phosphorus-containing waste gas generated in step S1 into the waste lye. The phosphorus-containing waste gas dissolves in the waste lye to generate phosphoric acid, which reacts with sodium carbonate and sodium hydroxide to generate sodium phosphate. By allowing the phosphorus-containing waste gas to react with the waste lye, the harmless treatment of the phosphorus-containing waste gas is achieved. At the same time, during the reaction process, the phosphorus-containing waste gas is continuously added, and the concentrations of sodium carbonate and sodium hydroxide in the waste lye are detected at intervals. When the concentrations of sodium carbonate and sodium hydroxide are lower than the threshold value, the addition of the phosphorus-containing waste gas into the waste lye is stopped. No other by-products are generated during the above preparation process, and the prepared sodium phosphate has high purity.

[0046] The chemical formula of the phosphorus-containing waste gas dissolved in water is: P2O5+3H2O-→2H3PO4.

[0047] The chemical formula of the reaction between phosphoric acid and sodium carbonate is: 2H3PO4+3Na2CO3-→2Na3PO4+3CO2↑+3H2O.

[0048] The chemical formula of the reaction between phosphoric acid and sodium hydroxide is: H3PO4+3NaOH-→Na3PO4+3H2O.

[0049] Example 2

[0050] The difference between this example and example 1 is that step S2 is different.

[0051] S2, the desorption agent is stored in a container, and then the yellow phosphorus tail gas is injected into the desorption agent, so that the yellow phosphorus tail gas reacts with the desorption agent to generate waste lye containing sodium sulfide, sodium carbonate and sodium phosphate. During the reaction, the solubility of sodium hydroxide in the waste lye is intermittently detected, and when the content of sodium hydroxide is lower than the threshold value, the addition of yellow phosphorus tail gas is stopped to avoid unreacted yellow phosphorus tail gas leakage.

[0052] Example 3

[0053] The difference between this embodiment and Example 1 is that step S3 is different. The content of sodium sulfide in the waste lye is detected, and when the content of sodium sulfide is lower than the threshold value, the addition of the oxidizing agent is stopped.

[0054] By detecting the content of sodium sulfide, the amount of oxidizing agent added is accurately controlled, and the problem of waste of oxidizing agent is solved.

[0055] Example 4

[0056] The difference between this embodiment and Example 1 is that step S3 is different.

[0057] S3, ozone is added to the waste lye containing sodium sulfide, sodium carbonate and sodium phosphate, so that the sodium sulfide in the waste lye generates elemental sulfur and sodium hydroxide.

[0058] The chemical formula of the reaction of sodium sulfide with ozone is: Na2S + O3 + H2O -→ S + 2NaOH + O2↑.

[0059] Example 5

[0060] The difference between this embodiment and Example 1 is that step S5 is different.

[0061] S5, the phosphorus-containing waste gas is added to the waste lye, the phosphorus-containing waste gas reacts with water to generate phosphoric acid, and the phosphoric acid reacts with sodium carbonate and sodium hydroxide to generate sodium phosphate. At the same time, the pH value of the waste lye is detected, and when the pH value is within a predetermined range, the addition of the phosphorus-containing waste gas to the waste lye is stopped.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that in S3, the total amount of hydrogen peroxide added is 0.1:1 compared to the total amount of waste lye.

[0064] After step S3 is completed, the content of sodium sulfide in the waste lye is detected.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 1 is that in S3, the total amount of hydrogen peroxide added is 0.5:1 compared to the total amount of waste lye.

[0067] After step S3 is completed, the content of sodium sulfide in the waste lye is detected.

[0068] By detecting the content of sodium sulfide in the waste lye after the completion of step S3 of example 1, comparative example 1 and comparative example 2, the following table can be obtained.

[0069] Table 1

[0070]

[0071]

[0072] From the results of table 1, the following conclusions can be drawn:

[0073] (1) When the ratio of the total amount of hydrogen peroxide added to the total amount of waste lye is greater than or equal to 0.25:1, the sodium sulfide in the waste lye can be completely oxidized by the hydrogen peroxide, and there will be no sodium sulfide remaining in the waste lye.

[0074] (2) When the ratio of the total amount of hydrogen peroxide added to the total amount of waste lye is less than 0.25:1, the sodium sulfide in the waste lye cannot be completely reacted, and there will be sodium sulfide remaining in the waste lye, which can affect the subsequent process.

[0075] Therefore, it is preferred that the ratio of the total amount of hydrogen peroxide added to the total amount of waste lye is 0.25:1, which can ensure that the sodium sulfide is completely reacted and also avoids waste of hydrogen peroxide.

[0076] Example 6

[0077] This embodiment provides a production system using the production method described in example 1, which includes

[0078] A reaction chamber, which can be a reaction cavity in the prior art. The inside of the reaction cavity is used to contain the waste lye.

[0079] A tail gas supply module, which is a preparation pipeline of yellow phosphorus tail gas in the prior art. The preparation pipeline is in communication with the reaction chamber. The yellow phosphorus tail gas can be released into the inside of the reaction chamber.

[0080] A desorption agent release module, which can be a nozzle. The nozzle is in connection with a container storing the desorption agent. The desorption agent release module can release the desorption agent into the inside of the reaction chamber when the desorption agent release module works. When the desorption agent is released into the inside of the reaction chamber, the desorption agent reacts with the yellow phosphorus tail gas to generate the waste lye. After the yellow phosphorus tail gas and the desorption agent are mixed, the waste lye contains sodium sulfide, sodium carbonate and sodium phosphate.

[0081] The oxidizing agent release module can also be a nozzle. The type of nozzle is adapted to the type of oxidizing agent. For example, when the oxidizing agent is ozone, the nozzle is a gas nozzle; when the oxidizing agent is hydrogen peroxide, the nozzle is a liquid nozzle. After the oxidizing agent is added to the waste lye, the sodium sulfide in the waste lye reacts with the oxidizing agent to generate elemental sulfur and sodium hydroxide. The elemental sulfur in the waste lye can be separated from the waste lye by manual filtration. The waste lye after the separation of the elemental sulfur still contains sodium carbonate, sodium phosphate, and sodium hydroxide.

[0082] To avoid adding too much oxidizing agent, a first detection module is arranged inside the reaction chamber. The first detection module can be a detector for detecting sodium sulfide in the prior art, which is mainly used to detect the content of sodium sulfide. When the first detector detects that the content of sodium sulfide is lower than a threshold value, the addition of oxidizing agent into the reaction chamber is stopped to avoid too much oxidizing agent.

[0083] The phosphorus-containing waste gas release module is in communication with the reaction chamber and is used for releasing phosphorus-containing waste gas. The phosphorus-containing waste gas release module can be a gas tank, which can release phosphorus-containing waste gas into the reaction chamber. The phosphorus-containing waste gas container can be connected with a preparation pipeline of yellow phosphorus tail gas, so that the phosphorus-containing waste gas generated during the preparation of yellow phosphorus tail gas is stored and released in the subsequent treatment process.

[0084] The phosphorus-containing waste gas is dissolved in the waste lye to generate phosphoric acid, which reacts with sodium carbonate and sodium hydroxide to generate sodium phosphate. By allowing the phosphorus-containing waste gas to react with the waste lye, the harmless treatment of the byproduct phosphorus-containing waste gas is achieved. At the same time, no other excess byproducts are generated in the above preparation process, and the purity of the prepared sodium phosphate is also high.

[0085] To avoid adding too much phosphorus-containing waste gas, a second detection module is also arranged inside the reaction chamber. The second detection module can detect the content of sodium carbonate and sodium hydroxide. When the content of sodium carbonate and sodium hydroxide is detected to be lower than a threshold value, the addition of phosphorus-containing waste gas is stopped to avoid adding too much phosphorus-containing waste gas.

[0086] Example 7

[0087] The difference between this embodiment and example 6 is that this embodiment provides a reaction chamber 1 adapted to the above production method. The inside of the reaction chamber 1 is a cavity, and the inside of the reaction chamber 1 is used to contain waste lye and carry out reactions.

[0088] The two sides of the reaction chamber 1 of this embodiment are respectively provided with a tail gas supply module and a releasing agent release module. The tail gas supply module releases yellow phosphorus tail gas into the inside of the reaction chamber 1, and the releasing agent release module releases releasing agent into the inside of the reaction chamber 1, and the releasing agent is in an atomized state. The oxidizing agent release module and the phosphorus-containing waste gas release module 7 are connected with the inside of the reaction chamber 1, so that the oxidizing agent and the phosphorus-containing waste gas can be released into the inside of the reaction chamber 1.

[0089] The reaction chamber 1 is provided with a connecting pipe 2, the inlet of the connecting pipe 2 is located at the lower end of the reaction chamber 1, the outlet of the connecting pipe 2 is arranged at the upper end of the reaction chamber 1, and a delivery pump 3 is arranged on the connecting pipe 2. The delivery pump 3 can suck the waste lye in the reaction chamber 1 and spray it into the reaction chamber 1 again, so as to accelerate the reaction rate of the yellow phosphorus tail gas and the stripping agent. At the same time, an atomizing nozzle 4 is arranged at the outlet of the connecting pipe 2, so as to realize the atomization of the waste lye and further improve the reaction rate.

[0090] In order to determine the reaction state, a stripping agent detection device is further arranged on the connecting pipe 2, which can detect the concentration change of the stripping agent, and then judge whether the reaction has been completed. The stripping agent detection device can be a detection device for detecting the concentration of sodium hydroxide in the prior art.

[0091] In the embodiment, a first three-way joint is arranged on the connecting pipe 2, one outlet of the first three-way joint is communicated with the atomizing nozzle 4, and the other outlet of the first three-way joint is connected to a filtering pipe. A filter 5 is arranged on the filtering pipe, which is used to filter out elemental sulfur in the filtering step. The filtering pipe further comprises an observation part 6 which is a transparent pipe. The observation part 6 is arranged on a section of the filtering pipe. An external operator can observe the turbidity state of the waste lye in the filtering pipe through the observation part 6. When the waste lye is relatively turbid, it indicates that the elemental sulfur has not been completely filtered out. When the waste lye is relatively clean, it indicates that the filtering effect of the elemental sulfur is good. At the same time, in order to ensure that the liquid can move along the predetermined path, valves are arranged at the two outlets of the first three-way joint. When the valve of the first three-way joint communicated with the atomizing nozzle 4 is opened, the waste lye can return to the inside of the reaction chamber 1 from the atomizing nozzle 4. When the valve corresponding to the filtering pipe is opened, the waste lye flows back into the reaction chamber 1 from the filtering pipe after being filtered.

[0092] It can be understood that in the embodiment, the atomization and backflow of the waste lye and the filtering of the elemental sulfur are realized by the connecting pipe 2 and a delivery pump 3 at the same time, which has low cost and high practicability.

[0093] In order to improve the reaction efficiency of the phosphorus-containing waste gas and the waste lye, the discharge pipe of the phosphorus-containing waste gas can also be connected to the connecting pipe 2 in the embodiment. A valve is arranged at the connection between the phosphorus-containing waste gas and the connecting pipe 2. When it is needed to add the phosphorus-containing waste gas into the reaction chamber 1, the valve at the connection between the phosphorus-containing waste gas and the connecting pipe 2 is opened, and the valves corresponding to the atomizing nozzle 4 and the filter 5 are closed. The phosphorus-containing waste gas is released into the reaction chamber 1 from the inlet of the connecting pipe 2. Since the inlet of the connecting pipe 2 is located at the lower end of the reaction chamber 1, the phosphorus-containing waste gas is directly released into the waste lye, so as to accelerate the reaction rate of the phosphorus-containing waste gas and the waste lye.

[0094] Embodiment 8

[0095] The embodiment is improved on the basis of Embodiment 7. Since the connecting pipe 2 is used for atomization, filtration and phosphorus-containing waste gas release at the same time, and the connecting pipe 2 is repeatedly used, after the filtration step is completed, there will be some elemental sulfur residues in the inner wall of the first tee joint and the inner wall of the connecting pipe 2 and other positions. Among them, with the re-atomization step, the elemental sulfur enters the atomization nozzle 4, and the elemental sulfur has the risk of blocking the atomization nozzle 4.

[0096] In order to solve the problem of blocking the atomization nozzle 4 caused by elemental sulfur, as shown in Figure 3 The embodiment also has a cleaning pump 8 on the connecting pipe 2. One end of the cleaning pump 8 communicates with the connecting pipe 2, and the other end of the cleaning pump 8 can communicate with the outside. The cleaning pump 8 works before the reaction starts, and the valve corresponding to the atomization nozzle 4 is opened. The cleaning pump 8 works to suck the elemental sulfur residues in the first tee joint and the inner wall of the connecting pipe 2 and release them to the outside, thereby realizing the cleaning of the first tee joint and the inner wall of the connecting pipe 2, and solving the problem of blocking the atomization nozzle 4 by elemental sulfur. Of course, the cleaning pump 8 is also provided with a valve, and when cleaning is not needed, the valve is in a closed state, thereby avoiding leakage.

[0097] Embodiment 9

[0098] The embodiment is improved on the basis of Embodiment 8. In order to make the cleaning effect of the cleaning pump 8 better, the cleaning pump 8 is preferably set as a forward and reverse pump in the embodiment, that is, the cleaning pump 8 can inject cleaning liquid into the connecting pipe 2, or can suck the cleaning liquid from the connecting pipe 2. Therefore, in order to supply the cleaning pump 8 with cleaning liquid and discharge the liquid, the mouth of the cleaning pump 8 is provided with a second tee joint. One end of the second tee joint is used for liquid discharge, and the other end of the second tee joint is connected with a cleaning liquid storage pool. Therefore, when cleaning is needed, the cleaning pump 8 is forward, and the cleaning liquid is injected into the connecting pipe 2. This process can flush away the residual elemental sulfur; then, the cleaning pump 8 is reversed, and the cleaning pump 8 extracts and discharges the injected cleaning liquid outward, avoiding the residues of the cleaning liquid and the elemental sulfur in the reaction chamber 1 and the connecting pipe 2. The two outlets of the second tee joint are also respectively provided with valves, thereby ensuring that the second tee joint can adapt to the working mode of the cleaning pump 8. At the same time, in order to realize the cleaning of the delivery pump 3, avoid the residues of the elemental sulfur in the gap inside the delivery pump 3, the delivery pump 3 can also be preferably a forward and reverse pump. When the cleaning pump 8 is forward and the cleaning liquid is injected into the connecting pipe 2, the delivery pump 3 is reversed, so that the cleaning liquid can normally flow through the inside of the delivery pump 3, realizing the flushing of the elemental sulfur inside the delivery pump 3; when the cleaning pump 8 is reversed and the cleaning liquid is extracted outward, the delivery pump 3 is forward, so that the cleaning liquid can normally flow through the delivery pump 3, avoiding the hindrance to the discharge of the cleaning liquid.

[0099] The above-mentioned are only embodiments of the present application, and the common knowledge of specific structures and characteristics in the scheme is not described too much. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the patent. The protection scope claimed in this application should be subject to the content of its claims, and the specific implementation mode and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A production method for producing sodium phosphate by using a phosphorus-containing waste gas, characterized by comprising: The method comprises the following steps ​ S1, preparing yellow phosphorus tail gas, and generating phosphorus-containing waste gas during the preparation of the yellow phosphorus tail gas; S2, reacting the prepared yellow phosphorus tail gas with an extracting agent to generate waste lye containing sodium sulfide, sodium carbonate and sodium phosphate; S3, adding an oxidizing agent into the waste lye, and reacting the sodium sulfide in the waste lye with the oxidizing agent to generate elemental sulfur and sodium hydroxide; S4, removing the elemental sulfur in the waste lye, and leaving sodium carbonate, sodium phosphate and sodium hydroxide in the waste lye; S5, adding the phosphorus-containing waste gas into the waste lye, and reacting the phosphorus-containing waste gas with water to generate phosphoric acid, and reacting the phosphoric acid with sodium carbonate and sodium hydroxide to generate sodium phosphate, In the S3, the ratio of the total amount of the added oxidizing agent to the total amount of the waste lye is 0.25:1, In the S3, the content of the sodium sulfide in the waste lye is detected, and when the content of the sodium sulfide is lower than a threshold value, the adding of the oxidizing agent is stopped, In the S5, the concentration of the sodium carbonate and / or the sodium hydroxide is detected, and when the concentration of the sodium carbonate and / or the sodium hydroxide is lower than a threshold value, the adding of the phosphorus-containing waste gas into the waste lye is stopped, In the S5, the PH value of the waste lye is detected, and when the PH value is within a predetermined range, the adding of the phosphorus-containing waste gas into the waste lye is stopped.

2. The production method according to claim 1, characterized by: In the S2, the extracting agent is sprayed to contact with the yellow phosphorus tail gas to react to generate the waste lye; Or; In the S2, the yellow phosphorus tail gas is injected into the extracting agent to react to generate the waste lye.

3. The production method according to claim 1, characterized by: In the S4, the elemental sulfur in the waste lye is removed by filtration.

4. A production system for producing a product by using the production method according to any one of claims 1 to 3, characterized by: Comprise a reaction chamber; a tail gas supply module, which is in communication with the reaction chamber, and which is used to release the yellow phosphorus tail gas into the reaction chamber; an extracting agent release module, which is in communication with the reaction chamber, and which is used to release the extracting agent into the reaction chamber; an oxidizing agent release module, which is in communication with the reaction chamber, and which is used to add the oxidizing agent into the reaction chamber; and a phosphorus-containing waste gas release module, which is in communication with the reaction chamber, and which is used to release the phosphorus-containing waste gas.

5. The production system of claim 4, wherein: Further comprise a first detection module, which is arranged in the reaction chamber, and which is used to detect the content of the sodium sulfide; And / or Further comprise a second detection module, which is arranged in the reaction chamber, and which is used to detect the content of the sodium carbonate and / or the sodium hydroxide.

Images