A stainless steel acid concentration detection, analysis and replenishment control system

Abstract

The invention discloses a control system for detecting, analyzing and replenishing the acid concentration of stainless steel acid solution, comprising: an automatic acid concentration detection and analysis device and an automatic acid concentration replenishment device; the automatic acid concentration detection and analysis device comprises: an online acid concentration analyzer, a precipitation device, an acid solution collection pipeline group and an acid solution sampling pipeline group; the automatic acid concentration replenishment device comprises: a control device with a PLC program, a nitric acid raw acid tank, a nitric acid delivery pipeline group, a hydrofluoric acid raw acid tank and a hydrofluoric acid delivery pipeline group; the control device is in communication with each control element in the automatic acid concentration detection and analysis device and the automatic acid concentration replenishment device. The above system can automatically collect the mixed acid in the mixed acid circulation tank and precipitate, filter, sample and analyze the mixed acid, and automatically control the nitric acid raw acid tank and the hydrofluoric acid raw acid tank to replenish the mixed acid circulation tank with the acid raw liquid according to the analysis results, so as to realize the unmanned automatic control mode of online analysis and replenishment of the acid concentration of stainless steel pickling.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel annealing and pickling, and in particular to a stainless steel acid solution acid concentration detection, analysis and replenishment control system. Background Art

[0002] During the continuous casting, hot rolling and heat treatment processes, scale will be generated on the surface of stainless steel during the heat treatment process. The presence of scale will affect the quality of the final product. Therefore, the stainless steel needs to be descaled before entering the subsequent processes. This is especially important for stainless steel that needs to have a unique surface.

[0003] The scale formed on the surface of stainless steel is dense and strong, and it is difficult to remove it easily. The current method of removing scale from stainless steel is pretreatment + pickling. Among them, pickling can not only remove the scale on the surface of stainless steel on the basis of pretreatment, but also remove the chromium-poor layer of the raw material, and generate a static oxide film, which gives the stainless steel surface corrosion resistance. Therefore, stainless steel pickling is an important process in the stainless steel processing process.

[0004] The types of acids used for stainless steel pickling include nitric acid, hydrofluoric acid, sulfuric acid, hydrochloric acid and phosphoric acid. Among them, sulfuric acid is mainly used for pickling Cr stainless steel. Since the temperature has a greater impact on the pickling effect of sulfuric acid than the concentration of the acid, sulfuric acid is more often used in low-concentration and high-temperature environments. Hydrofluoric acid has a lower boiling point and stronger toxicity than hydrochloric acid, so it is necessary to be very careful when using it. Hydrochloric acid and hydrofluoric acid not only have an erosive effect on the oxide scale, but also on the metal material itself. Therefore, hydrochloric acid and hydrofluoric acid are rarely used alone. Usually, nitric acid and mixed acid obtained by mixing nitric acid and hydrochloric acid are used more often. However, the effect of mixed acid obtained by mixing nitric acid and hydrochloric acid is not very significant compared with the effect of using hydrochloric acid alone, so mixed acid obtained by mixing nitric acid and hydrochloric acid is not used as acid solution. Since the mixed acid obtained by mixing nitric acid and hydrofluoric acid has the best pickling effect, an excellent surface can be obtained in a short time, and the risk of air corrosion is also small, which has nothing to do with the type of steel, the mixed acid obtained by mixing nitric acid and hydrofluoric acid is widely used for pickling of stainless steel.

[0005] Nitric acid is an oxidant that can promote the floating degradation of stainless steel and has a maintenance property that will not damage the corrosion-resistant film on the surface of stainless steel. Hydrofluoric acid is a reducing agent. The increase in solution concentration and temperature will make the reducing property stronger. The mixed acid obtained by mixing nitric acid and hydrofluoric acid as the pickling acid is to utilize the protective effect between the protective layer of the metal formed by the reduction effect of hydrofluoric acid and oxide scale and the floating degradation of nitric acid, and at the same time, the concentration and temperature changes of nitric acid and hydrofluoric acid are used to adjust the degree of pickling.

[0006] In the mixed acid pickling process of stainless steel, the concentration and temperature changes of nitric acid and hydrofluoric acid are key parameter indicators of the pickling quality of stainless steel surface. Different steel grades need to be pickled according to different acid concentrations and temperature control conditions. At the same time, the pickling concentration and temperature need to be maintained in a stable state, and only a small amount of fluctuation is allowed within the appropriate range.

[0007] At present, the continuous annealing mixed acid production line used by domestic stainless steel manufacturers uses offline laboratory analysis method for the detection and analysis of acid concentration of acid solution, that is, the acid solution samples currently in use are manually collected and sent to the laboratory, and the acid concentration analysis value is obtained by the experimenter manually operating the analysis instrument. The production personnel perform acid concentration replenishment operations based on the acid concentration analysis result value. The acid concentration replenishment is divided into fully manual or semi-automatic methods. The number of acid concentration replenishment and the number of acid concentration analysis are basically the same frequency, or the production personnel need to adjust the acid concentration replenishment frequency based on experience. Since the offline laboratory acid concentration analysis requires manual transfer of acid solution samples for testing, it also determines that the time spent on its analysis is related to the distance between the laboratory and the production line. The closer the distance, the faster the analysis results are obtained, and the longer the distance, the slower the analysis results are obtained. In addition, the use of laboratory acid concentration analysis instruments is operated by different experimenters. Although the test methods are consistent, the operating habits of different experimenters will also lead to different degrees of differences in acid concentration analysis values. Since the offline laboratory acid concentration analysis method often has the disadvantages of long time consumption and large errors, this directly affects the timely replenishment of acid concentration. If the acid concentration is too low due to untimely replenishment, the removal effect of the oxide scale on the stainless steel surface will be poor, which will affect the quality of the final product; if the acid concentration is increased due to excessive replenishment, it will lead to waste of acid consumption costs and increase costs. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a stainless steel acid liquid acid concentration detection analysis and replenishment control system which can automatically collect mixed acid in a mixed acid circulation tank and precipitate, filter, sample and analyze the mixed acid, and automatically control a nitric acid original acid tank and a hydrofluoric acid original acid tank to replenish the acid stock solution in the mixed acid circulation tank according to the analysis result. The system can replenish the acid stock solution lacking in the mixed acid circulation tank in time, and the replenished acid solution can not only meet the pickling concentration requirement, but also effectively reduce the acid waste rate.

[0009] In order to solve the problem that the pickling concentration cannot be replenished to the appropriate concentration in time, and there is always too much or too little acid stock solution replenishment, the present invention aims to ensure that the acid solution always meets the pickling concentration requirements under the condition of low waste rate. The technical solution adopted by the present invention is: the above-mentioned stainless steel acid solution acid concentration detection, analysis and replenishment control system comprises: acid concentration automatic detection and analysis equipment and acid concentration automatic replenishment equipment; The acid concentration automatic detection and analysis equipment comprises: an online acid concentration analyzer, a precipitation device, an acid liquid collection pipeline group and an acid liquid sampling pipeline group; The acid liquid collection pipeline group comprises: at least one acid liquid collection pipeline, and an acid liquid collection pump and a first valve are sequentially arranged on each acid liquid collection pipeline from the inlet to the outlet direction; the number of the acid liquid collection pipelines is consistent with the number of mixed acid circulation tanks and corresponds one to one, the inlet of each acid liquid collection pipeline extends into the acid liquid in the corresponding mixed acid circulation tank, and the outlet of each acid liquid collection pipeline is connected to the acid liquid inlet of the precipitation device; The acid sampling pipeline group comprises: an acid sampling pipeline, on which a sampling pump is arranged, the outlet of the acid sampling pipeline is connected to the sample inlet of the online acid concentration analyzer, and the inlet of the acid sampling pipeline extends into the clear liquid of the corresponding precipitation device; The acid concentration automatic replenishment equipment comprises: a control device with a PLC program, a nitric acid raw acid tank, a nitric acid delivery pipeline group, a hydrofluoric acid raw acid tank and a hydrofluoric acid delivery pipeline group; The nitric acid delivery pipeline group comprises: at least one nitric acid delivery pipeline, on each nitric acid delivery pipeline, a first acid pump and a second valve are sequentially arranged from the inlet to the outlet direction; the number of the nitric acid delivery pipelines is consistent with the number of mixed acid circulation tanks and corresponds one to one, the inlet of each nitric acid delivery pipeline is connected to the outlet of the nitric acid raw acid tank, and the outlet of each nitric acid delivery pipeline is connected to the first acid liquid inlet of the corresponding mixed acid circulation tank; The hydrofluoric acid delivery pipeline group comprises: at least one hydrofluoric acid delivery pipeline, on each hydrofluoric acid delivery pipeline, a second acid pump and a third valve are sequentially arranged from the inlet to the outlet direction; the number of the hydrofluoric acid delivery pipelines is consistent with the number of mixed acid circulation tanks and corresponds one to one, the inlet of each hydrofluoric acid delivery pipeline is connected to the outlet of the hydrofluoric acid raw acid tank, and the outlet of each hydrofluoric acid delivery pipeline is connected to the second acid liquid inlet of the corresponding mixed acid circulation tank; The control device is communicatively connected with the online acid concentration analyzer, the pump start and close control device of the acid liquid collection pump, the start and close control device of the first valve, the pump start and close control device of the sampling extraction pump, the pump start and close control device of the first acid addition pump, the start and close control device of the second valve, the pump start and close control device of the second acid addition pump, and the start and close control device of the third valve.

[0010] The control device can calculate the acid concentration replenishment amount according to the detection and analysis result value of the online acid concentration analyzer. This calculation was originally calculated manually by people. Now, this set of calculation formulas is simply compiled into the PLC program, and the calculation is performed by the PLC program. This set of calculation formulas belongs to mature technology, so this set of calculation formulas is not attached here separately. Those skilled in the art are familiar with this set of calculation formulas. After the control device calculates the corresponding nitric acid stock solution replenishment amount and hydrofluoric acid stock solution replenishment amount, it controls the opening and closing time of the first valve and the opening and closing time of the second valve as needed to achieve the required amount of nitric acid stock solution replenishment and hydrofluoric acid stock solution replenishment.

[0011] Furthermore, in the aforementioned stainless steel acid liquid acid concentration detection, analysis and replenishment control system, a flushing port is provided on the sedimentation device, a flushing pipe is connected to the flushing port, and a water valve is provided on the flushing pipe; a drain port is provided at the bottom of the sedimentation device, a drain pipe is connected to the drain port, and a drain valve is provided on the drain pipe; the control device is communicated with the opening and closing control device of the water valve and the opening and closing control device of the drain valve, and the control device can automatically control the opening and closing of the water valve and the opening and closing of the drain valve under the control of the PLC program.

[0012] Furthermore, in the aforementioned stainless steel acid liquid acid concentration detection, analysis and replenishment control system, the water valve and the drain valve are both electromagnetic valves.

[0013] Furthermore, in the aforementioned stainless steel acid liquid acid concentration detection, analysis and replenishment control system, an overflow port is provided on the precipitation device, an overflow pipe is connected to the overflow port, and an overflow valve is provided on the overflow pipe; the control device and the opening and closing control device of the overflow valve are both communicated with each other.

[0014] Furthermore, in the aforementioned stainless steel acid liquid acid concentration detection, analysis and replenishment control system, the first valve, the second valve and the third valve are all pneumatic valves.

[0015] Furthermore, in the aforementioned stainless steel acid liquid acid concentration detection analysis and replenishment control system, the mass percentage concentration of the nitric acid stock solution in the nitric acid original acid tank is 68%±2%; the mass percentage concentration of the hydrofluoric acid stock solution in the hydrofluoric acid original acid tank is 55%±2%; the ratio of the nitric acid stock solution to the hydrofluoric acid stock solution in the mixed acid circulation tank is 3±0.2:1. A more preferred solution is: the mass percentage concentration of the nitric acid stock solution in the nitric acid original acid tank is 68%; the mass percentage concentration of the hydrofluoric acid stock solution in the hydrofluoric acid original acid tank is 55%; the ratio of the nitric acid stock solution to the hydrofluoric acid stock solution in the mixed acid circulation tank is 3:1.

[0016] The beneficial effects of the present invention are as follows: the above-mentioned stainless steel acid liquid acid concentration detection, analysis and replenishment control system can automatically collect the mixed acid in the mixed acid circulation tank and precipitate, filter, sample and analyze the mixed acid, and automatically control the nitric acid original acid tank and the hydrofluoric acid original acid tank to replenish the acid stock solution to the mixed acid circulation tank according to the analysis results, which can not only reduce the waste rate of the acid stock solution, but also ensure that the acid solution always meets the pickling concentration requirements, thereby realizing the unmanned automatic control mode of online analysis and replenishment of stainless steel pickling acid concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a partial flow chart of a stainless steel acid solution acid concentration detection, analysis and replenishment control system described in this embodiment.

[0018] in: 1. Mixed acid circulation tank; 2. Acid collection pump; 3. First valve; 4. Sedimentation device; 5. Water valve; 6. Overflow valve; 7. Drain valve; 8. Sampling pump; 9. Online acid concentration analyzer; 10. Nitric acid tank; 11. First acid pump; 12. Second valve; 13. Hydrofluoric acid tank; 14. Second acid pump; 15. Third valve; 100. Acid collection pipeline; 200. Acid sampling pipeline; 300. Flushing pipe; 400. Overflow pipe; 500. Drain pipe; 600. Nitric acid delivery pipeline; 700. Hydrofluoric acid delivery pipeline. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] Example embodiments will be described more fully below with reference to the accompanying drawings, but the example embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, the purpose of providing these embodiments is to make the present disclosure thorough and complete and to enable those skilled in the art to fully understand the scope of the present disclosure.

[0021] A stainless steel acid solution acid concentration detection, analysis and replenishment control system described in this embodiment includes: acid concentration automatic detection and analysis equipment and acid concentration automatic replenishment equipment.

[0022] like Figure 1 As shown, the acid concentration automatic detection and analysis equipment in this embodiment includes: an online acid concentration analyzer 9, a precipitation device 4, an acid liquid collection pipeline group and an acid liquid sampling pipeline group.

[0023] The acid collection pipeline group includes: at least one acid collection pipeline 100, and an acid collection pump 2 and a first valve 3 are sequentially arranged on each acid collection pipeline 100 from the inlet to the outlet. The number of the acid collection pipelines 100 is consistent with the number of the mixed acid circulation tanks 1 and corresponds one to one. The inlet of each acid collection pipeline 100 extends into the acid in the corresponding mixed acid circulation tank 1, and the outlet of each acid collection pipeline 100 is connected to the acid inlet of the precipitation device 4. In order to understand the structure more intuitively, Figure 1 A schematic diagram is drawn in which one group of mixed acid circulation tanks is used as an example. When there are more than two groups of mixed acid circulation tanks, the principle is the same.

[0024] Among them, the acid sampling pipeline group includes: an acid sampling pipeline 200, on which a sampling extraction pump 8 is arranged, the outlet of the acid sampling pipeline 200 is connected to the sample inlet of the online acid concentration analyzer 9, and the inlet of the acid sampling pipeline 200 extends into the clear liquid of the corresponding precipitation device 4.

[0025] like Figure 1As shown, the acid concentration automatic replenishing equipment in this embodiment includes: a control device with a PLC program, a nitric acid raw acid tank 10, a nitric acid delivery pipeline group, a hydrofluoric acid raw acid tank 13 and a hydrofluoric acid delivery pipeline group.

[0026] Wherein, the nitric acid delivery pipeline group includes: at least one nitric acid delivery pipeline 600, on each nitric acid delivery pipeline 600, a first acid pump 11 and a second valve 12 are sequentially arranged from the inlet to the outlet direction; the number of the nitric acid delivery pipelines 600 is consistent with the number of the mixed acid circulation tanks 1 and corresponds one to one, the inlet of each nitric acid delivery pipeline 600 is connected to the outlet of the nitric acid raw acid tank 10, and the outlet of each nitric acid delivery pipeline 600 is connected to the first acid liquid inlet of the corresponding mixed acid circulation tank 1.

[0027] Wherein, the hydrofluoric acid delivery pipeline group includes: at least one hydrofluoric acid delivery pipeline 700, and a second acid pump 14 and a third valve 15 are sequentially arranged on each hydrofluoric acid delivery pipeline 700 from the inlet to the outlet direction; the number of the hydrofluoric acid delivery pipelines 700 is consistent with the number of the mixed acid circulation tanks 1 and corresponds one to one, the inlet of each hydrofluoric acid delivery pipeline 700 is connected to the outlet of the hydrofluoric acid original acid tank 13, and the outlet of each hydrofluoric acid delivery pipeline 700 is connected to the second acid liquid inlet of the corresponding mixed acid circulation tank 1.

[0028] The control device is communicatively connected with the online acid concentration analyzer 9, the pump start and close control device of the acid liquid collection pump 2, the start and close control device of the first valve 3, the pump start and close control device of the sampling extraction pump 8, the pump start and close control device of the first acid addition pump 11, the start and close control device of the second valve 12, the pump start and close control device of the second acid addition pump 14, and the start and close control device of the third valve 15.

[0029] The first valve 2, the second valve 12 and the third valve 15 are preferably pneumatic valves.

[0030] In order to ensure the accuracy of each acid concentration detection and analysis, in this embodiment, a flushing port is provided on the precipitation device 4, a flushing pipe 300 is connected to the flushing port, and a water valve 5 is provided on the flushing pipe 300; the control device is communicated with the opening and closing control device of the water valve 5, and the control program is programmed into the PLC program. The control device can automatically control the opening and closing of the water valve 5 under the control of the PLC program. Among them, the water valve 5 is preferably an electromagnetic valve.

[0031] The bottom of the sedimentation device 4 has a drain port, a drain pipe 500 is connected to the drain port, and a drain valve 7 is arranged on the drain pipe 500. The control device is in communication with the opening and closing control device of the drain valve 7, and the control program is programmed into the PLC program. The control device can automatically control the opening and closing of the drain valve 7 under the control of the PLC program.

[0032] The drain valve 7 is preferably an electromagnetic valve.

[0033] By flushing and draining, it is ensured that the subsequently collected acid liquid will not be affected by the previously collected acid sample when entering the precipitation device, thereby improving the accuracy of each acid concentration detection and analysis.

[0034] The nitric acid stock solution in the nitric acid tank 10 and the hydrofluoric acid stock solution in the hydrofluoric acid tank 13 are mixed in a certain ratio and put into the mixed acid circulation tank 1. At this time, the mixed acid in the mixed acid circulation tank 1 is used to pickle the stainless steel. In this embodiment, the mass percentage concentration of the nitric acid stock solution in the nitric acid tank 10 is 68%±2%; the mass percentage concentration of the hydrofluoric acid stock solution in the hydrofluoric acid tank 13 is 55%±2%; the ratio of the nitric acid stock solution to the hydrofluoric acid stock solution in the mixed acid circulation tank 1 is 3±0.2:1.

[0035] A more preferred solution is: the mass percentage concentration of the nitric acid stock solution in the nitric acid original acid tank 10 is 68%; the mass percentage concentration of the hydrofluoric acid stock solution in the hydrofluoric acid original acid tank 13 is 55%; and the ratio of the nitric acid stock solution to the hydrofluoric acid stock solution in the mixed acid circulation tank 1 is 3:1.

[0036] An overflow pipe 400 is also provided on the sedimentation device 4 , and an overflow valve 6 is provided on the overflow pipe 400 . An opening and closing control device of the overflow valve 6 is in communication with the control device.

[0037] During the operation of the automatic acid concentration detection and analysis equipment, the control device controls the automatic acid concentration detection and analysis equipment to work according to a certain time rule, such as completing an automatic acid concentration collection, precipitation, filtration, sampling, detection and analysis cycle every 30 minutes. The specific working process is as follows: the control device sends a signal to the pump start-stop control device of the acid liquid collection pump 2 and the start-stop control device of the first valve 3 to start the acid liquid collection pump 2, open the first valve 3, and extract a certain amount of mixed acid in the mixed acid circulation tank 1 into the precipitation device 4, and then the control device sends a signal to the pump start-stop control device of the acid liquid collection pump 2 and the start-stop control device of the first valve 3 to close the acid liquid collection pump 2 and the first valve 3. At this time, the mixed acid pumped into the precipitation device 4 is precipitated in the precipitation device 4, and a clear liquid is formed on the upper layer after precipitation. The control device sends a signal to the pump start and stop control device of the sampling pump 8 according to the set sedimentation time, and waits for the sedimentation to be completed, so that the sampling pump 8 is opened, and a certain amount of clear liquid in the sedimentation device 4 is extracted into the online acid concentration analyzer 9. Then the control device sends a signal to the pump start and stop control device of the sampling pump 8 to close the sampling pump 8. The online acid concentration analyzer 9 sends the analysis result to the control device after detection and analysis. At the same time, the control system sends a signal to the start and stop control device of the water valve 5 to open the water valve 5, and water enters the sedimentation device through the flushing pipe 300 to flush the sedimentation device. The control system sends a signal to the start and stop control device of the drainage valve 7 according to the set drainage time, so that the drainage valve 7 is opened to drain the water in the sedimentation device. The control device sends a signal to the start and stop control device of the water valve 5 according to the set water closing time, so that the water valve 5 is closed. The control device sends a signal to the start and stop control device of the drainage valve 7 according to the set drainage closing time, so that the drainage valve 7 is closed, and a cycle process is completed. During operation, the next cycle process can be started immediately after the previous cycle process ends.

[0038] The online acid concentration analyzer 9 is used to automatically collect, precipitate, filter, sample, analyze and discharge the mixed acid used in the stainless steel production process. The concentration analysis principle is to use the different properties of the conductivity of nitric acid, hydrofluoric acid and metal fluoride in the mixed acid, and to calculate the concentration value by adding additives to measure the change in the conductivity of nitric acid, hydrofluoric acid and metal fluoride. The additives are sulfuric acid and ferric nitrate solution, which can be directly purchased on the market.

[0039] In the mixed acid, nitric acid is a strong acid, and the conductivity changes greatly, while HF is a weak acid, and the amplitude is small. When Fe is present, HF releases H+ during the process of forming FeF2+, which greatly increases the conductivity. Therefore, if additives are added, the conductivity will be greatly improved with the HF content. The concentration of HF is determined by this increased conductivity, and the calculated concentration is guaranteed by the nitric acid concentration and temperature. The metal ions dissolved in the oxide scale and the base material will dissolve in the state of various fluorine compounds. If metal and compound substances (F-, SCN-, EDTA-, etc.) are added to the pickling solution, the concentration of H+ increases the conductivity by combining with the existing compounds, and the increase is proportional to the ability of the metal to combine with HF (metal concentration).

[0040] During the operation of the automatic acid concentration replenishment equipment, the control device compares the acid concentration obtained by the online acid concentration analyzer 9 with the acid concentration set in the control device. After calculating the replenishment amount of nitric acid stock solution and the replenishment amount of hydrofluoric acid stock solution based on the comparison, the control device sends a signal to the pump start and stop control device of the first acid pump 11 and the pump start and stop control device of the second acid pump 12, and controls the opening time of the first acid pump 11 and the opening time of the second acid pump 12 as required to replenish the corresponding amount of acid stock solution into the mixed acid circulation tank 1.

[0041] Develop a matching acid concentration analyzer data interactive HMI screen to realize the visualization of the pickling concentration replenishment function of each roll during the stainless steel pickling process. The online acid analyzer data is connected with the control device through communication to form an online detection and analysis of mixed acid concentration and a fully automatic matching system for mixed acid concentration replenishment, laying the foundation for product quality optimization, reducing the waste rate of acid stock solution, reducing processing costs, and realizing unmanned control mode of online analysis and replenishment of stainless steel pickling acid concentration.

[0042] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A stainless steel acid solution acid concentration detection, analysis and supply control system, characterized in that: include: Acid concentration automatic detection and analysis equipment and acid concentration automatic replenishment equipment; The acid concentration automatic detection and analysis equipment comprises: an online acid concentration analyzer, a precipitation device, an acid liquid collection pipeline group and an acid liquid sampling pipeline group; The acid liquid collection pipeline group comprises: at least one acid liquid collection pipeline, and an acid liquid collection pump and a first valve are sequentially arranged on each acid liquid collection pipeline from the inlet to the outlet direction; the number of the acid liquid collection pipelines is consistent with the number of mixed acid circulation tanks and corresponds one to one, the inlet of each acid liquid collection pipeline extends into the acid liquid in the corresponding mixed acid circulation tank, and the outlet of each acid liquid collection pipeline is connected to the acid liquid inlet of the precipitation device; The acid sampling pipeline group comprises: an acid sampling pipeline, on which a sampling pump is arranged, the outlet of the acid sampling pipeline is connected to the sample inlet of the online acid concentration analyzer, and the inlet of the acid sampling pipeline extends into the clear liquid of the corresponding precipitation device; The acid concentration automatic replenishment equipment comprises: a control device with a PLC program, a nitric acid raw acid tank, a nitric acid delivery pipeline group, a hydrofluoric acid raw acid tank and a hydrofluoric acid delivery pipeline group; The nitric acid delivery pipeline group comprises: at least one nitric acid delivery pipeline, on each nitric acid delivery pipeline, a first acid pump and a second valve are sequentially arranged from the inlet to the outlet direction; the number of the nitric acid delivery pipelines is consistent with the number of mixed acid circulation tanks and corresponds one to one, the inlet of each nitric acid delivery pipeline is connected to the outlet of the nitric acid raw acid tank, and the outlet of each nitric acid delivery pipeline is connected to the first acid liquid inlet of the corresponding mixed acid circulation tank; The hydrofluoric acid delivery pipeline group comprises: at least one hydrofluoric acid delivery pipeline, on each hydrofluoric acid delivery pipeline, a second acid pump and a third valve are sequentially arranged from the inlet to the outlet direction; the number of the hydrofluoric acid delivery pipelines is consistent with the number of mixed acid circulation tanks and corresponds one to one, the inlet of each hydrofluoric acid delivery pipeline is connected to the outlet of the hydrofluoric acid raw acid tank, and the outlet of each hydrofluoric acid delivery pipeline is connected to the second acid liquid inlet of the corresponding mixed acid circulation tank; The control device is communicatively connected with the online acid concentration analyzer, the pump start and close control device of the acid liquid collection pump, the start and close control device of the first valve, the pump start and close control device of the sampling extraction pump, the pump start and close control device of the first acid addition pump, the start and close control device of the second valve, the pump start and close control device of the second acid addition pump, and the start and close control device of the third valve.

2. A stainless steel acid solution acid concentration detection, analysis and replenishment control system according to claim 1, characterized in that: A flushing port is provided on the sedimentation device, a flushing pipe is connected to the flushing port, and a water valve is provided on the flushing pipe; a drain port is provided at the bottom of the sedimentation device, a drain pipe is connected to the drain port, and a drain valve is provided on the drain pipe; the control device is communicated with the opening and closing control device of the water valve and the opening and closing control device of the drain valve.

3. A stainless steel acid solution acid concentration detection, analysis and replenishment control system according to claim 2, characterized in that: The water valve and the drain valve are both electromagnetic valves.

4. A stainless steel acid solution acid concentration detection, analysis and replenishment control system according to claim 1, 2 or 3, characterized in that: An overflow port is arranged on the sedimentation device, an overflow pipe is connected to the overflow port, and an overflow valve is arranged on the overflow pipe; the control device is communicated with the opening and closing control device of the overflow valve.

5. A stainless steel acid solution acid concentration detection, analysis and replenishment control system according to claim 1, characterized in that: The first valve, the second valve and the third valve are all pneumatic valves.

6. A stainless steel acid solution acid concentration detection, analysis and supply control system according to claim 1, characterized in that: The mass percentage concentration of the nitric acid stock solution in the nitric acid original acid tank is 68%±2%; the mass percentage concentration of the hydrofluoric acid stock solution in the hydrofluoric acid original acid tank is 55%±2%; the ratio of the nitric acid stock solution to the hydrofluoric acid stock solution in the mixed acid circulation tank is 3±0.2:

1.

7. A stainless steel acid solution acid concentration detection, analysis and replenishment control system according to claim 1, characterized in that: The mass percentage concentration of the nitric acid stock solution in the nitric acid original acid tank is 68%; the mass percentage concentration of the hydrofluoric acid stock solution in the hydrofluoric acid original acid tank is 55%; and the ratio of the nitric acid stock solution to the hydrofluoric acid stock solution in the mixed acid circulation tank is 3:1.

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