End point identification method for precipitation reaction in rare earth sulfate production

Abstract

The invention discloses an end point identification method for precipitation reaction in rare earth sulfate production, which belongs to the field of intelligent monitoring control, and comprises the following steps: receiving potential information through a server, sequentially controlling the addition amount of hydrogen peroxide and ammonia water according to the information, and sequentially identifying a hydrogen peroxide reaction end point and a final reaction end point. The reaction endpoint can be accurately identified, so that the reaction can be terminated in time, and the purity of the rare earth sulfate is finally improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of intelligent monitoring control, and more particularly, to a method for identifying the end point of a precipitation reaction in rare earth sulfate production. BACKGROUND

[0002] In the existing production of rare earth sulfate (such as Ce(SO4)2), the batch precipitation process has two reaction end points due to the two reaction processes of hydrogen peroxide and ammonia water. The existing method controls the end point of the hydrogen peroxide reaction by calculating the reactants before initial feeding, which lacks effective control and thus cannot determine the end point. The end point of the ammonia water reaction is determined by chemical analysis (such as chromatographic analysis) or by taking pictures of the precipitate, which has the problems of difficult sampling time control and slow analysis speed, resulting in inaccurate determination of the end point time and insufficient or excessive reaction.

[0003] The above background art is for the convenience of understanding the present application and is not the known art publicly known to the public before the filing of the present application. SUMMARY

[0004] To solve the above problems, the present application provides a method for identifying the end point of a precipitation reaction in rare earth sulfate production, which can accurately identify the reaction end point and thus terminate the reaction in time, ultimately improving the purity of rare earth sulfate.

[0005] A method for identifying the end point of a precipitation reaction in rare earth sulfate production, which receives potential information through a server and sequentially controls the addition amounts of hydrogen peroxide and ammonia water according to the information and sequentially identifies the end points of the hydrogen peroxide reaction and the final reaction.

[0006] The method receives potential information through a server and accurately controls the addition amounts of hydrogen peroxide for the hydrogen peroxide reaction and ammonia water for the ammonia water reaction, which realizes accurate identification of the end point of the precipitation reaction in rare earth sulfate production, timely termination of the reaction, and intelligent operation of the entire process, including the following steps: S1, in the calibration stage: the server receives a set initial potential value, a set reaction end point potential value in the hydrogen peroxide reaction stage, a calculated hydrogen peroxide amount, and a set reaction end point potential value in the ammonia water reaction stage. The initial potential value is denoted as V0, the reaction end point potential value in the hydrogen peroxide reaction stage is denoted as the first target potential value, i.e., V 目1 , the calculated hydrogen peroxide amount is denoted as M 双 , and the set reaction end point potential value in the hydrogen peroxide reaction stage is denoted as the second target potential value, i.e., V 目2 ; S2, in the first stage: the server receives the first real-time potential value of the potential sensor, the first real-time potential value is recorded as V1, and V1 is compared with V0, if the difference between V1 and V0 is within the set threshold, it indicates that the materials in the kettle are correct, and S3 is entered; if the difference between V1 and V0 is outside the set threshold, an alarm instruction is outputted; S3, in the second stage: the server sends a feeding instruction to the hydrogen peroxide feeding pipe to add hydrogen peroxide into the kettle, which is recorded as the hydrogen peroxide feeding instruction, and the feeding amount is recorded as feeding 双 , the hydrogen peroxide feeding pipe opens to execute the feeding information, and the server receives the second real-time potential value of the potential sensor, which is recorded as V2 t ; S5, in the second stage: the server continues to receive the second real-time potential value V2 t of the potential sensor, and compares V2 t with V 目1 , if the absolute value of the difference is within the threshold, an alarm instruction is outputted, and if the absolute value of the difference is outside the threshold, S6 is entered; S6, in the second stage: the server sends a hydrogen peroxide feeding instruction to the hydrogen peroxide feeding pipe to add hydrogen peroxide into the kettle, which is recorded as the hydrogen peroxide feeding instruction, and the feeding amount is recorded as feeding 双i , the hydrogen peroxide feeding pipe opens to execute the feeding information, and the server continues to receive the third real-time potential value V3 t of the potential sensor, the real-time potential value of the potential sensor received by the server at the moment when the hydrogen peroxide feeding instruction is sent is recorded as V3i, V3 t is compared with V3i, if V3 t >2V3i, it indicates that the feeding is successful, and S7 is entered, otherwise, an alarm instruction is outputted; S7, in the second stage: the server continues to receive the third real-time potential value V3 t of the potential sensor, the third real-time potential value V3 t is the current potential value, and the potential value of the potential sensor received by the server at the previous moment is recorded as the previous potential value V3 （t-1）， , V3 t is compared with V3 （t-1） , if the difference is within the threshold, S8 is entered, if the difference is outside the threshold, the comparison is continued until the difference is within the threshold, and S8 is entered; S8, in the second stage: the server continues to receive the third real-time potential value V3 t of the potential sensor, and compares V3 t with V 目1 , if the absolute value of the difference is within the threshold, S9 is entered, if the absolute value of the difference is outside the threshold, S6, S7 and the comparison between V3 t and V 目1 are repeated until the absolute value of the difference is within the threshold; S9, in the third stage: The server sends an opening instruction to the ammonia dripper, which executes the instruction and continuously drips ammonia into the reactor. At the same time, the server receives the fourth real-time potential value V4 from the potential sensor. t Comparison with V4 t With V 目2 If the difference is within the threshold, proceed to S10; if the absolute value of the difference is outside the threshold, continue comparing until the absolute value of the difference is within the threshold, then proceed to S10. S10, the server sends a shut-off instruction to the ammonia dropper, indicating that the reaction has reached its endpoint.

[0007] Optionally, after S3 and before S5, the following is also included: S4, in the second phase: the server continues to receive the second real-time potential value V2 from the potential sensor. t The second real-time potential value V2 t The potential value at the current moment is recorded as the potential value V2 received by the server from the potential sensor at the previous moment. （t-1）， Comparison V2 t With V2 （t-1） If the difference is within the threshold, proceed to S5; if the difference is outside the threshold, continue comparing until the difference is within the threshold, then proceed to S5.

[0008] Optionally, S3 also includes: V2 t Compare with V2, if V2 t If the value is >2V2, it indicates that the feeding was successful. Then proceed to S4. Otherwise, output an alarm command.

[0009] Optionally, the addition 双 =0.5 M 双 .

[0010] Optionally, the initial feed amount is 0.375 M. 双 .

[0011] Optionally, the supplement 双i = k*supplement 双(i-1) , where i is the number of times material is replenished, i>1, 0 <k<1。

[0012] Optionally, the k and V 目1 / V2 t The ratio is directly proportional.

[0013] Optionally, in S9, the server also receives the real-time pH value from the pH sensor, and the real-time pH value is recorded as pH. t V4 t With V 目2 When the difference is within the threshold, pH is also required. t -7 The difference is within the threshold.

[0014] Optionally, the potential sensor and the pH sensor are installed at 5 cm to 10 cm above the uppermost stirring slurry in the gap type reaction kettle, and the pH sensor is above the potential sensor.

[0015] Compared with the prior art, the application has the following beneficial effects: On one hand, the application can identify the end point of the reaction of hydrogen peroxide and ammonia, and on the other hand, the application can accurately determine the whole end point through a linkage mode, and a server monitoring is added to improve the purity of the final product. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0017] Figure 1 is the interaction diagram of the application; Figure 2 is a schematic diagram of the installation position of the potential sensor and the pH sensor of the application; The specific embodiments of the application will be described in detail below. DETAILED DESCRIPTION

[0018] The application will be further described below with reference to the drawings.

[0019] In the description of the application, it should be noted that unless otherwise explicitly specified and limited, the terms “installation”, “connection”, “linkage” should be understood in a broad sense, for example, it can be fixed connection, or indirect connection through an intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0020] In the description of the application, it should be understood that the terms “upper”, “lower”, “front”, “rear”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In the description of the application, the meaning of “multiple” is two or more, unless otherwise specified and limited.

[0021] The terms "first", "second", "third", "fourth" etc. (if any) in the description and claims of this application and in the above abstract are used for distinguishing between similar objects, not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of these terms herein is to be construed to cover the embodiments of the application described herein, for example, the embodiments of the application described herein can be carried out in other sequences than the one described herein, unless the context clearly indicates otherwise. Furthermore, the terms "comprising" and "including" and any of their derivatives, are intended to be construed as encompassing not only the listed members, but also others not specifically listed. For example, a process, method, system, product, or apparatus that comprises a list of steps or units is not necessarily limited to those steps or units specifically listed, but can include additional steps or units not specifically listed or inherent to such process, method, product, or apparatus.

[0022] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0023] The technical solutions of the present application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and some embodiments can not be described again for the same or similar concepts or processes.

[0024] Please refer to Figures 1-2 , Figure 1 is the interactive diagram of the present application, Figure 2 is a schematic diagram of installation positions of the potential sensor and the pH sensor of the present application.

[0025] A method for identifying the end point of a precipitation reaction in rare earth sulfate production, comprising the following steps: S1, in the calibration stage: the server receives a set initial potential value, a set reaction end point potential value in the hydrogen peroxide reaction stage, a calculated hydrogen peroxide amount, and a set reaction end point potential value in the ammonia water reaction stage, the initial potential value is denoted as V0, the reaction end point potential value in the hydrogen peroxide reaction stage is denoted as the first target potential value, i.e. V 目1 , the calculated hydrogen peroxide amount is denoted as M 双 , and the set reaction end point potential value in the hydrogen peroxide reaction stage is denoted as the second target potential value, i.e. V 目2 .

[0026] V0 is the potential value of a completely trivalent Ce ion at pH 2-3.

[0027] The first target potential information is the potential when the trivalent Ce ion is completely reacted (i.e. perfect reaction end point).

[0028] S2, in the first stage: the server receives the first real-time potential value of the potential sensor 3, which is denoted as V1, and compares it with V0. If the difference between V1 and V0 is within a set threshold, it indicates that the material in the tank is correct, and S3 is entered. If the difference between V1 and V0 is outside the set threshold, an alarm instruction is output.

[0029] S3, in the second stage: the server sends a dosing instruction (denoted as hydrogen peroxide dosing instruction) to the hydrogen peroxide dosing pipe 5 to add hydrogen peroxide into the tank, and the dosing amount is denoted as dosing amount 双 , the hydrogen peroxide dosing pipe 5 opens to execute the dosing information, and the server receives the second real-time potential value of the potential sensor 3, which is denoted as V2 t , the real-time potential value of the potential sensor 3 received by the server at the time when the hydrogen peroxide dosing instruction is sent is denoted as V2, V2 t is compared with V2 t . If V2 t is much greater than V2 (for example, V2 is more than twice V2), it indicates that the dosing is successful, and S4 is entered. If not, an alarm instruction is output.

[0030] In this step, V2 = V1. Before the hydrogen peroxide dosing instruction is sent, the material in the tank does not change, and the potential value output by the potential sensor 3 does not change.

[0031] In this step, dosing amount 双 = 0.5 M 双 .

[0032] S4, in the second stage: the server continues to receive the second real-time potential value V2 of the potential sensor 3 t , the second real-time potential value V2 t is the current potential value, and the potential value of the potential sensor 3 received by the server at the previous time is denoted as the previous potential value V2 （t-1）， . V2 t is compared with V2 （t-1） . If the difference is within the threshold, S5 is entered. If the difference is outside the threshold, the comparison is continued until the difference is within the threshold, and S5 is entered.

[0033] S5, in the second stage: the server continues to receive the second real-time potential value V2 of the potential sensor 3 t , and V2 t is compared with V 目1 . If the absolute value of the difference is within the threshold, an alarm instruction is output. If the absolute value of the difference is outside the threshold, S6 is entered.

[0034] If V2t V 目1 If the absolute value of the difference is within the threshold, it means that the initial amount of trivalent Ce ions in the tank is less than the specified amount for production, and the input may be insufficient. An alarm instruction is output to find the cause.

[0035] S6, in the second stage: the server sends a hydrogen peroxide supplement instruction to the hydrogen peroxide feeding pipe 5 to supplement hydrogen peroxide into the tank, and the supplement amount is 双i The hydrogen peroxide feeding pipe 5 opens to execute the supplement information, and the server continues to receive the third real-time potential value V3 t of the potential sensor 3 at this time. The real-time potential value V3i of the potential sensor 3 received by the server at the time when the hydrogen peroxide supplement instruction is sent is recorded, and V3 t is compared with V3i. If V3 t is much larger than V3i (for example, V3 t is more than twice V3i), it means that the supplement is successful, and S7 is turned to, otherwise, an alarm instruction is output.

[0036] When supplementing for the first time, 0.375 M i of hydrogen peroxide is supplemented. 双 , S7, in the second stage: the server continues to receive the third real-time potential value V3 t of the potential sensor 3. The third real-time potential value V3 t is the potential value at the current time, and the potential value V3 （t-1）， of the potential sensor 3 received by the server at the previous time is recorded as the potential value at the previous time. t is compared with V3 （t-1） . If the difference is within the threshold, S8 is turned to, and if the difference is outside the threshold, the comparison is continued until the difference is within the threshold, and S8 is turned to.

[0037] S8, in the second stage: the server continues to receive the third real-time potential value V3 t of the potential sensor 3. V3 t is compared with V 目1 . If the absolute value of the difference is within the threshold, S9 is turned to, and if the absolute value of the difference is outside the threshold, S6, S7 and the present step are repeated until the absolute value of the difference is within the threshold.

[0038] The supplement amount of hydrogen peroxide is 双i = k*supplement amount of hydrogen peroxide 双(i-1) , i is the number of times of supplement, i>1, 0<k<1, and k is within the range, so that the supplement amount of the next time is less than the supplement amount of the previous time, and the supplement amount is less as the end point is approached, thereby avoiding excessive addition of hydrogen peroxide.

[0039] Further, in order to reasonably supplement, k is proportional to V 目1 / V2 t , and V目1 V2 t The greater the ratio, the greater k.

[0040] When V3 t is greater than V 目1 , it indicates that the hydrogen peroxide reaction has reached the end point, and the next ammonia water reaction stage is initiated.

[0041] S9, in the third stage: the server sends an open instruction to the ammonia water dropping tube 6, and the ammonia water dropping tube 6 executes the instruction to continuously and uninterruptedly drop ammonia water into the kettle, while the server receives the fourth real-time potential value V4 t of the potential sensor 3 and compares V4 t with V 目2 . If the difference is within the threshold, go to S10, and if the absolute value of the difference is outside the threshold, continue to compare until the absolute value of the difference is within the threshold, and go to S10.

[0042] When the absolute value of the difference between V4 t and V 目2 is within the threshold, it indicates that the ammonia water reaction has reached the end point.

[0043] S10, the server sends a close instruction to the ammonia water dropping tube 6, and the ammonia water dropping tube 6 executes the instruction to stop dropping ammonia water into the reaction kettle, and the reaction is terminated.

[0044] Further, there is an error in the end point recognition of the aforementioned ammonia water reaction stage of S9-S10, when the ammonia water is excessively dropped, the absolute value of the difference between V4 t and V 目2 is also within the threshold, at this time, a part of the precipitate (product of the ammonia water reaction) is charged due to the adsorption of cations and causes dispersion, part of which is converted into water-soluble ions and affects V4 t , causing recognition errors. In order to solve this phenomenon, the following operations are performed.

[0045] Again referring to Figure 2 , S9, in the third stage: the server sends an open instruction to the ammonia water dropping tube 6, and the ammonia water dropping tube 6 executes the instruction to continuously and uninterruptedly drop ammonia water into the kettle, while the server receives the fourth real-time potential value V4 t of the potential sensor 3 and the real-time pH value of the pH sensor, which is recorded as pH t . Compare V4 t with V 目2 , and compare whether pH t is < 7, when the difference between V4 t and V 目2 is outside the threshold and pH t < 7, continue to compare until the difference is within the threshold and pH t-7 difference is within the threshold value (0< threshold value is not greater than 2), go to 10.

[0046] When V4 t With V 目2 Difference is within the threshold value, and pH t -7 difference is within the threshold value, indicating that the ammonia water reaction is just to the end point.

[0047] S10, the server sends a closing instruction to the ammonia dropping tube 6, and the ammonia dropping tube 6 executes the instruction to stop dropping ammonia water into the reaction kettle, and the reaction is terminated. Through the linkage control, the excess ammonia water is avoided to cause the product to be reduced, thereby improving the purity of the product.

[0048] In the present application, in order to detect accuracy, the potential sensor and the PH sensor can reflect the overall situation of the reaction system in the whole reaction kettle and prevent mechanical collision and turbulence. The potential sensor 3 and the PH sensor 4 are installed at 5 cm ~10 cm above the uppermost stirring paddle 2 in the gap type reaction kettle 1. The PH sensor 4 is located above the potential sensor 3. The stirring paddle drives the fluid downward at this position. The turbulence is weak but the mixing is uniform at this position. The reaction precipitated particles are avoided to directly impact the sensor PH sensor 4 and the potential sensor 3, thereby prolonging the service life. The potential sensor 3 and the PH sensor 4 can be installed on the same bracket.

[0049] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for identifying the endpoint of a precipitation reaction in rare earth sulfate production, characterized in that, This method receives potential information from a server and sequentially controls the addition of hydrogen peroxide and ammonia based on this information, and sequentially identifies the hydrogen peroxide reaction endpoint and the final reaction endpoint, including the following steps: S1, During the calibration phase: The server receives the set initial potential value, the set reaction endpoint potential value for the hydrogen peroxide reaction stage, the calculated amount of hydrogen peroxide, and the set reaction endpoint potential value for the ammonia reaction stage. The initial potential value is recorded as V0, and the reaction endpoint potential value for the hydrogen peroxide reaction stage is recorded as the first target potential value, i.e., V 目1 The calculated amount of hydrogen peroxide is denoted as M. 双 The set endpoint potential value of the hydrogen peroxide reaction stage is the second target potential value, i.e., V. 目2 ; S2, in the first stage: The server receives the first real-time potential value from the potential sensor, which is recorded as V1, and compares it with V0. If the difference between V1 and V0 is within the set threshold, it indicates that the material in the vessel is correct, and proceeds to S3; if the difference between V1 and V0 is outside the set threshold, an alarm command is output. S3, in the second stage: The server sends a hydrogen peroxide addition command to the hydrogen peroxide addition pipe to add hydrogen peroxide into the reactor, denoted as the hydrogen peroxide addition command, and the addition amount is denoted as the addition amount. 双 The hydrogen peroxide feed pipe is opened to execute the feed information. At the same time, the server receives the second real-time potential value from the potential sensor, which is recorded as V2. t ; S5, in the second phase: The server continues to receive the second real-time potential value V2 from the potential sensor. t Comparison with V2 t With V 目1 If the absolute value of the difference is within the threshold, an alarm command is output; if the absolute value of the difference is outside the threshold, proceed to S6. S6, in the second stage: The server sends a command to the hydrogen peroxide feeding pipe to replenish hydrogen peroxide into the reactor, denoted as the hydrogen peroxide replenishment command, and the replenishment amount is [replenishment amount]. 双i The hydrogen peroxide feed pipe is opened to execute the replenishment request, and at the same time the server continues to receive the third real-time potential value V3 from the potential sensor. t The real-time potential value of the potential sensor received by the server at the moment the hydrogen peroxide replenishment command is issued is recorded as V3i. t Compared to V3i, if V3 t If the value is >2.0V3i, it indicates that the feeding was successful. Then switch to S7. Otherwise, output an alarm command. S7, in the second phase: The server continues to receive the third real-time potential value V3 from the potential sensor. t The third real-time potential value V3 t The current potential value is recorded as the potential value V3 received by the server from the potential sensor at the previous moment. （t-1）， Comparison V3 t With V3 （t-1） If the difference is within the threshold, proceed to S8; if the difference is outside the threshold, continue comparing until the difference is within the threshold, then proceed to S8. S8, in the second phase: The server continues to receive the third real-time potential value V3 from the potential sensor. t Comparison with V3 t With V 目1 If the absolute value of the difference is within the threshold, proceed to S9; if the absolute value of the difference is outside the threshold, repeat S6, S7, and comparison V3. t With V 目1 Until the absolute value of the difference reaches the threshold; S9, in the third stage: The server sends an opening instruction to the ammonia dripper, which executes the instruction and continuously drips ammonia into the reactor. At the same time, the server receives the fourth real-time potential value V4 from the potential sensor. t Comparison with V4 t With V 目2 If the difference is within the threshold, proceed to S10; if the absolute value of the difference is outside the threshold, continue comparing until the absolute value of the difference is within the threshold, then proceed to S10. S10, the server sends a shut-off instruction to the ammonia dropper, indicating that the reaction has reached its endpoint.

2. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 1, characterized in that, After S3 and before S5, it also includes: S4, in the second phase: the server continues to receive the second real-time potential value V2 from the potential sensor. t The second real-time potential value V2 t The potential value at the current moment is recorded as the potential value V2 received by the server from the potential sensor at the previous moment. （t-1）， Comparison V2 t With V2 （t-1） If the difference is within the threshold, proceed to S5; if the difference is outside the threshold, continue comparing until the difference is within the threshold, then proceed to S5.

3. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 2, characterized in that, S3 also includes: V2 t Compare with V2, if V2 t If the value is >2V2, it indicates that the feeding was successful. Then proceed to S4. Otherwise, output an alarm command.

4. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 1, characterized in that, Said plus 双 =0.5 M 双 .

5. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 1, characterized in that, The initial feed volume was 0.375 M. 双 .

6. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 1, characterized in that, The supplement 双i = k*supplement 双(i-1) , where i is the number of times material is replenished, i>1, 0 <k<1。 7. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 6, characterized in that, The k and V 目1 / V2 t The ratio is directly proportional.

8. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 1, characterized in that, In S9, the server also receives the real-time pH value from the pH sensor, and the real-time pH value is recorded as pH. t V4 t With V 目2 When the difference is within the threshold, pH is also required. t -7 The difference is within the threshold.

9. The method for identifying the endpoint of the precipitation reaction in rare earth sulfate production according to claim 8, characterized in that, The potential sensor and pH sensor are installed 5 cm to 10 cm above the topmost agitator in the intermittent reactor, with the pH sensor located above the potential sensor.

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