A method for identifying the end point of a precipitation reaction in rare earth sulfate production

Abstract

The application discloses a method for identifying the end point of a precipitation reaction in rare earth sulfate production, and belongs to the field of intelligent monitoring control. The method receives potential information through a server, and sequentially controls the addition amount of hydrogen peroxide and ammonia water according to the information, and sequentially identifies the end point of the hydrogen peroxide reaction and the final reaction end point. The application can accurately identify the reaction end point, so that the reaction can be timely terminated, 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, slow analysis speed, and thus inaccurate determination of the end point, leading to 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 disclosed to the public before 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 amount of hydrogen peroxide and ammonia water according to the information and sequentially identifies the end point of the hydrogen peroxide reaction and the final reaction end point.

[0006] The method receives potential information through a server and accurately controls the addition amount of hydrogen peroxide for the hydrogen peroxide reaction and the addition amount of ammonia water for the ammonia water reaction, achieving accurate identification of the end point of the precipitation reaction in rare earth sulfate production, timely stopping of the reaction, and intelligent operation of the entire process, including the following steps:

[0007] S1, in the calibration stage: the server receives a set initial potential value, a set reaction end point potential value of the hydrogen peroxide reaction stage, a calculated hydrogen peroxide amount, and a set reaction end point potential value of the ammonia water reaction stage. The initial potential value is denoted as V0, the reaction end point potential value of 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 reaction end point potential value of the ammonia water reaction stage is denoted as the second target potential value, i.e., V目2 ;

[0008] 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.

[0009] 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 ;

[0010] 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.

[0011] 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 >2V3i, it indicates that the feeding was successful. If not, the alarm command will be output.

[0012] 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.

[0013] 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;

[0014] 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.

[0015] S10, the server sends a shut-off instruction to the ammonia dropper, indicating that the reaction has reached its endpoint.

[0016] 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.

[0017] 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.

[0018] Optionally, the addition 双 =0.5 M 双 .

[0019] Optionally, the initial feed amount is 0.375 M. 双 .

[0020] 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。

[0021] Optionally, the k and V 目1 / V2 t The ratio is directly proportional.

[0022] Optionally, in S9, the server also receives a real-time pH value of the pH sensor, and the real-time pH value is denoted as pH t , V4 t and V 目2 , when the difference is within a threshold value, the pH t -7 difference is within a threshold value.

[0023] Optionally, the potential sensor and the pH sensor are installed 5cm-10cm above the uppermost stirring paddle in the gap-type reaction kettle, and the pH sensor is located above the potential sensor.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] On one hand, the application can identify the end point of the reaction of hydrogen peroxide and ammonia water, and on the other hand, the application can accurately determine the end point of the whole reaction through a linkage mode, and a server monitoring is added to improve the purity of the final product. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application 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 present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0027] Figure 1 is the interaction diagram of the application;

[0028] Figure 2 is a schematic diagram of the installation position of the potential sensor and the pH sensor of the application;

[0029] Legend: 1, gap-type reaction kettle, 2, upper stirring paddle, 3, potential sensor, 4, pH sensor, 5, hydrogen peroxide feeding pipe, 6, ammonia water dropping tube. DETAILED DESCRIPTION

[0030] The application will be further described below with reference to the drawings.

[0031] 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.

[0032] In the description of the present application, it is to be understood by the terms "upper", "lower", "front", "back", "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, only for the convenience of describing the present 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 present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0033] The terms "first", "second", "third", "fourth" and the like used in the description and claims of the present application, and the above-mentioned drawings (if any) are used to distinguish similar objects, and do not necessarily have to describe a particular order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] In order to make the purposes, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0035] 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 the same or similar concepts or processes may not be described in some embodiments.

[0036] Please refer to Figures 1-2 , Figure 1 is the interaction diagram of the present application, Figure 2 is a schematic diagram of the installation position of the potential sensor and the pH sensor of the present application.

[0037] A method for identifying the end point of the precipitation reaction in the production of rare earth sulfate, comprising the following steps:

[0038] S1, in the calibration stage: the server receives the set initial potential value, the set reaction end potential value of the hydrogen peroxide reaction stage, the calculated hydrogen peroxide amount and the set reaction end potential value of the ammonia water reaction stage, the initial potential value is denoted as V0, the reaction end potential value of 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 potential value of the ammonia water reaction stage is denoted as the second target potential value, i.e. V 目2 .

[0039] V0 is the potential value of the completely trivalent Ce ion at pH 2-3.

[0040] The first target potential information is the potential of the completely reacted (i.e. perfect reaction end) trivalent Ce ion.

[0041] 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 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 output.

[0042] S3, in the second stage: the server sends a feeding instruction (denoted as hydrogen peroxide feeding instruction) to the hydrogen peroxide feeding pipe 5 to add hydrogen peroxide into the kettle, and the feeding amount is denoted as feeding 双 ; the hydrogen peroxide feeding pipe 5 opens to execute the feeding 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 moment when the hydrogen peroxide feeding instruction is sent is denoted as V2, and V2 t is compared with V2; if V2 t is much greater than V2 (for example, V2 t is more than twice V2), it indicates that the feeding is successful, and S4 is entered; otherwise, an alarm instruction is output.

[0043] In this step, V2 = V1, because there is no change in the materials in the kettle before the hydrogen peroxide feeding instruction is sent, the potential value output by the potential sensor 3 does not change.

[0044] In this step, feeding 双 = 0.5 M 双 .

[0045] S4, in the second stage: the server continues to receive the second real-time potential value V2 t of the potential sensor 3; 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 moment is denoted as the previous moment potential value V2 （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.

[0046] S5, in the second stage: The server continues to receive the second real-time potential value V2 from potential sensor 3. 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.

[0047] If V2 appears in this step t With V 目1 If the absolute value of the difference is within the threshold, it indicates that the initial amount of trivalent Ce ions added to the reactor is less than the production specification, which may be due to insufficient feed. An alarm command will be output to find the cause.

[0048] S6, in the second stage: The server sends a command to hydrogen peroxide feed pipe 5 to replenish hydrogen peroxide into the reactor (referred to as the hydrogen peroxide replenishment command), the replenishment amount is [replenishment amount]. 双i The hydrogen peroxide feed pipe 5 is opened to execute the feeding information, and at the same time the server continues to receive the third real-time potential value V3 from the potential sensor 3. t The real-time potential value of potential sensor 3 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 Much larger than V3i (e.g., V3) t If the amount is more than twice that of V3i, it indicates successful feeding. If not, switch to S7; otherwise, output an alarm command.

[0049] When replenishing the material for the first time, replenish in pairs. i =0.375 M 双 ,

[0050] S7, in the second phase: The server continues to receive the third real-time potential value V3 from potential sensor 3. t The third real-time potential value V3 t The potential value at the current moment is recorded as the potential value V3 received by the server from potential sensor 3 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.

[0051] S8, in the second phase: the server continues to receive the third real-time potential value V3 from potential sensor 3. t Comparison with V3 t With V目1 If the absolute value of the difference is within the threshold, go to S9, if the absolute value of the difference is outside the threshold, repeat S6, S7 and the present step until the absolute value of the difference is within the threshold.

[0052] Supplement 双i = k*Supplement 双(i-1) i is the number of the supplement, i>1, 0<k<1, k is within the range, so that the next supplement is less than the previous supplement, and the closer to the end, the less supplement, thereby avoiding excessive hydrogen peroxide addition.

[0053] Further, in order to reasonably supplement, k is proportional to V 目1 / V2 t in a positive ratio ， V 目1 / V2 t The larger the ratio, the larger k.

[0054] When V3 t and V 目1 the absolute value of the difference is within the threshold, indicating that the hydrogen peroxide reaction has reached the end point, and the next ammonia water reaction stage is initiated.

[0055] S9, in the third stage: the server sends an open instruction to the ammonia water dropping tube 6, the ammonia water dropping tube 6 executes the instruction to continuously and uninterruptedly drop ammonia water into the kettle, and the server receives the fourth real-time potential value V4 t of the potential sensor 3, compares V4 t and V 目2 , if the difference is within the threshold, go to S10, 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.

[0056] When V4 t and V 目2 the absolute value of the difference is within the threshold, indicating that the ammonia water reaction has reached the end point.

[0057] S10, the server sends a close instruction to the ammonia water dropping tube 6, the ammonia water dropping tube 6 executes the instruction to stop dropping ammonia water into the reaction kettle, and the reaction is terminated.

[0058] Further, there is an error in the identification of the end point of the aforementioned S9-S10 ammonia water reaction stage, when the ammonia water is excessively added, 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 adsorbed by cations and charged to cause dispersion, part of which is converted into water-soluble ions and affects V4 t , resulting in identification error. In order to solve this phenomenon, the following operation is performed.

[0059] Again, referring to Figure 2, S9, in the third stage: the server sends an open instruction to the ammonia dropping tube 6, the ammonia dropping tube 6 executes the instruction, continuously and uninterruptedly drops ammonia into the kettle, and the server receives the fourth real-time potential value V4 of the potential sensor 3 t and the real-time pH value of the pH sensor, the real-time pH value is recorded as pH t . Compare V4 t with V 目2 , and compare pH t whether <7, when V4 t and V 目2 the difference is outside the threshold value and pH t <7, continue to compare until the difference is within the threshold value, and pH t -7 difference within the threshold value (0 < threshold value not greater than 2), go to 10.

[0060] When V4 t and V 目2 the difference is within the threshold value, and pH t -7 difference within the threshold value, indicating that the ammonia reaction is just at the end point.

[0061] S10, the server sends a close instruction to the ammonia dropping tube 6, the ammonia dropping tube 6 executes the instruction, stops adding ammonia into the reaction kettle, and the reaction is terminated. Through the linkage control, it avoids the excess ammonia to reduce the product, thereby improving the purity of the product.

[0062] 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 service life is prolonged by avoiding the direct impact of the reaction precipitated particles on the pH sensor 4 and the potential sensor 3. The potential sensor 3 and the pH sensor 4 can be installed on the same bracket.

[0063] 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 they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for 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 end point of a precipitation reaction in the production of rare earth sulfates, characterized by, The method receives potential information through a server and sequentially controls the adding amount of hydrogen peroxide and ammonia water according to the information and sequentially identifies the hydrogen peroxide reaction end point and the final reaction end point, and comprises the following steps: S1, in the calibration stage: the server receives the set initial potential value, the set reaction end potential value of the hydrogen peroxide reaction stage, the calculated hydrogen peroxide amount and the set reaction end potential value of the ammonia water reaction stage, the initial potential value is recorded as V0, the reaction end potential value of the hydrogen peroxide reaction stage is recorded as the first target potential value, that is, V 目1 , the calculated hydrogen peroxide amount is recorded as M 双 , and the set reaction end potential value of the ammonia water reaction stage is recorded as the second target potential value, that is, 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 hydrogen peroxide feeding instruction to the hydrogen peroxide feeding pipe, denoted as hydrogen peroxide feeding instruction, and the feeding amount is denoted as feeding amount 双 ; the hydrogen peroxide feeding pipe opens to execute the feeding information, and the server receives a second real-time potential value of the potential sensor, denoted as V2 t ; S5, in the second phase: the server continues to receive the second real-time potential value V2 of the potential sensor t , compares V2 t with V 目1 , if the absolute value of the difference is within the threshold, outputs an alarm instruction, and if the absolute value of the difference is outside the threshold, goes to S6; S6, in the second stage: the server sends a command to the hydrogen peroxide feeding pipe to add hydrogen peroxide into the tank, denoted as the hydrogen peroxide feeding command, and the feeding amount is the supplement 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 of the potential sensor t The real-time potential value V3i of the potential sensor received by the server at the time of the hydrogen peroxide feeding command is sent is denoted as V3 t V3i is compared, if V3 t >2.0V3i, indicating that the feeding is successful, then S7 is turned to, otherwise, an alarm command is output S7, in the second stage: the server continues to receive the third real-time potential value V3 of the potential sensor t , the third real-time potential value V3 t is the current time potential value, and the potential value of the potential sensor received by the server at the previous time is recorded as the previous time potential value V3 （t-1）， V3 t is compared with V3 （t-1） , if the difference is within the threshold value, turn to S8, if the difference is outside the threshold value, continue to compare until the difference is within the threshold value, and turn to S8; S8, in the second phase: the server continues to receive a third real-time potential value V3 of the potential sensor t , compares V3 t with V 目1 , if the absolute value of the difference is within a threshold, goes to S9, if the absolute value of the difference is outside the threshold, repeats S6, S7 and the comparison V3 t with V 目1 until the absolute value of the difference is within the threshold; S9, in the third stage: the server sends an open instruction to the ammonia dropping tube, the ammonia dropping tube executes the instruction, continuously and uninterruptedly drops ammonia into the kettle, and the server receives a fourth real-time potential value V4 of the potential sensor t , compares V4 t and V 目2 , if the difference is within a threshold value, turn to S10, if the absolute value of the difference is outside the threshold value, continue to compare until the absolute value of the difference is within the threshold value, and turn to S10; S10, the server sends a closing instruction to the ammonia water dropping tube, indicating that the reaction has reached the end point.

2. The method for identifying the end point of the precipitation reaction in the production of rare earth sulfate according to claim 1, characterized by, S3, before S5, further comprises: S4, in the second stage: the server continues to receive the second real-time potential value V2 of the potential sensor t , the second real-time potential value V2 t is the potential value at the current moment, and the potential value of the potential sensor received by the server at the previous moment is denoted as the previous moment potential value V2 （t-1）， , the second real-time potential value V2 t is compared with V2 （t-1） , if the difference is within a threshold value, turn to S5, and if the difference is outside the threshold value, continue to compare until the difference is within the threshold value, and then turn to S5.

3. The method for identifying the end point of the precipitation reaction in the production of rare earth sulfate according to claim 2, characterized by, S3, further comprising: V2 t Comparing with V2, if V2 t >2V2, indicating that the feeding is successful, then turn to S4, otherwise, output an alarm instruction.

4. The method for identifying the end point of a precipitation reaction in the production of a rare earth sulfate according to claim 1, characterized in that, The addition of 双 = 0.5 M 双 .

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

6. The method for identifying the end point of a precipitation reaction in the production of a rare earth sulfate according to claim 1, characterized by, The supplement 双i = k*supplement 双(i-1) , i is the number of the feeding, i > 1, 0 < k < 1.

7. The method for identifying the end point of the precipitation reaction in the production of rare earth sulfate according to claim 6, characterized by, The k is proportional to the ratio of V 目1 / V2 t .

8. The method for identifying the end point of a precipitation reaction in the production of a rare earth sulfate according to claim 1, characterized by, In S9, the server also receives the real-time pH value of the pH sensor, which is denoted as pH t , V4 t and V 目2 are within the threshold, the pH t value is within the threshold of -7.

9. The method for identifying the end point of the precipitation reaction in the production of rare earth sulfate according to claim 8, characterized by, The potential sensor and the PH sensor are installed at 5 cm-10 cm above the uppermost stirring paddle in the gap type reaction kettle, and the PH sensor is located above the potential sensor.

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