A combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores

Abstract

This utility model discloses a combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores, including a silicon block cleaning unit, a silicon core cleaning unit, and a waste liquid utilization unit. Its advantages are: by directing the high-concentration waste acid generated from silicon block pickling to the main etching process of the silicon core, where acid purity requirements are lower, the system achieves resource-based cascade utilization of waste acid, directly saving on hazardous waste outsourcing costs and reducing the consumption of fresh acid for silicon core cleaning, while also lowering the wastewater treatment load. Secondly, it reduces the total amount of waste acid and wastewater generated at the source, alleviating environmental treatment pressure and aligning with the concepts of green manufacturing and circular economy. Simultaneously, the system uses waste acid for the main etching process and high-purity acid for reinforcement etching, combined with final-stage fresh ultrapure water rinsing, effectively preventing secondary contamination of the silicon core by impurities in the waste liquid, ensuring that the final cleanliness of the silicon core meets requirements.

Description

Technical Field

[0001] This utility model relates to the field of polycrystalline silicon production technology, specifically to a combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores. Background Technology

[0002] Electronic-grade polycrystalline silicon requires extremely high purity, typically above 11N. As the core raw materials for pulling monocrystalline silicon, silicon blocks and silicon cores must have their surface metal impurities and particulate contaminants removed through a strict wet chemical cleaning process. Their cleanliness directly determines the quality and electrical properties of the final monocrystalline silicon.

[0003] Currently, manufacturers of electronic-grade polysilicon generally use independent automated cleaning lines to process silicon ingots and silicon cores. While the processes of silicon ingot cleaning lines and silicon core cleaning lines are similar, typically including alkaline washing, acid washing, rinsing, and drying, they operate completely independently. The main disadvantages of this independent operation model are: firstly, although the waste acid in the silicon ingot acid washing tank no longer meets the high cleanliness requirements of the silicon ingot itself, it still has a high acid concentration and etching ability, yet it is directly treated as hazardous waste, resulting in extremely high treatment costs and a serious waste of chemical resources; secondly, the rinsing wastewater generated from silicon ingot cleaning is also directly discharged, increasing the load on the wastewater treatment system and environmental pressure; and thirdly, the lack of coordination between the two cleaning systems prevents optimal resource allocation. Utility Model Content

[0004] To address the above problems, the purpose of this invention is to provide a combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores. This system can selectively and controllably utilize the waste acid generated from silicon block cleaning and the rinsing wastewater from specific stages in the silicon core cleaning process, which has lower requirements for the cleaning medium. This enables the cascade utilization of chemicals and significantly reduces the cost of hazardous waste treatment and the consumption of fresh chemicals.

[0005] This utility model is implemented by the following technical solution: A combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores includes a silicon block cleaning unit, a silicon core cleaning unit, and a waste liquid utilization unit. The silicon block cleaning unit includes a silicon block alkaline washing tank, a silicon block alkaline rinsing tank, a silicon block acid washing assembly, a silicon block acid rinsing assembly, and a silicon block drying tank arranged sequentially along the process flow. The silicon core cleaning unit includes a silicon core alkaline washing tank, a silicon core alkaline rinsing tank, a silicon core acid washing assembly, a silicon core acid rinsing assembly, and a silicon core drying tank arranged sequentially along the process flow. The waste liquid utilization unit includes a waste acid conveying pipeline and a wastewater conveying pipeline. The two ends of the waste acid conveying pipeline are respectively connected to the outlet of the waste acid buffer tank of the silicon block pickling assembly and the inlet of the silicon core pickling tank of the silicon core pickling assembly. A first flow control valve and an acid concentration monitoring device are installed on the waste acid conveying pipeline. The two ends of the wastewater conveying pipeline are respectively connected to the outlet of the wastewater buffer tank of the silicon block acid rinsing assembly and the inlet of the silicon core acid rinsing tank of the silicon core acid rinsing assembly. A second flow control valve and a water quality monitoring device are installed on the wastewater conveying pipeline.

[0006] Furthermore, the silicon block pickling assembly includes a silicon block acid mixing tank and at least two silicon block pickling tanks arranged in series along the process flow. The outlet of the silicon block acid mixing tank is connected to the inlet of the last silicon block pickling tank via a pipeline. The outlets of the silicon block pickling tanks other than the first-stage silicon block pickling tank are connected to the inlets of the silicon block pickling tanks preceding them. The outlet of the first-stage silicon block pickling tank is connected to the inlet of the waste acid storage tank via a pipeline.

[0007] Furthermore, the silicon core acid washing assembly includes a main etching tank; the outlet of the waste acid buffer tank is connected to the inlet of the main etching tank through the waste acid conveying pipeline, and the outlet of the main etching tank is connected to the inlet of the waste acid storage tank through a pipeline.

[0008] Furthermore, the silicon core acid washing assembly also includes a silicon core acid mixing tank and a reinforcing etching tank disposed along the process flow after the main etching tank; the outlet of the silicon core acid mixing tank is connected to the inlet of the reinforcing etching tank through a pipeline, and the outlet of the reinforcing etching tank is connected to the inlet of the main etching tank through a pipeline.

[0009] Furthermore, the silicon block acid rinsing assembly includes at least three silicon block acid rinsing tanks arranged sequentially along the process flow. The inlets of all silicon block acid rinsing tanks except the last one are connected to the outlets of the silicon block acid rinsing tanks following the last one. The outlets of all silicon block acid rinsing tanks except the first one are connected to the inlets of the silicon block acid rinsing tank preceding the first one. The outlet of the first-stage silicon block acid rinsing tank is connected to the inlet of the wastewater buffer tank via a pipeline. The outlet of the ultrapure water storage tank is connected to the inlet of the final stage silicon block acid rinsing tank via a pipeline.

[0010] Furthermore, the silicon core acid rinsing assembly includes at least three silicon core acid rinsing tanks arranged sequentially along the process flow. The outlet of the last-stage silicon core acid rinsing tank is connected to the inlet of the second-to-last-stage silicon core acid rinsing tank via a pipeline. The outlet of the wastewater buffer tank is connected to the inlet of the second-to-last-stage silicon core acid rinsing tank via a wastewater conveying pipeline. The outlet of the second-to-last-stage silicon core acid rinsing tank is connected to the inlet of the silicon core acid rinsing tank preceding it. The outlet of the first-stage silicon core acid rinsing tank is connected to the inlet of the wastewater storage tank. The outlet of the ultrapure water storage tank is connected to the inlet of the final stage silicon core acid rinsing tank via a pipeline; the outlet of the first stage silicon core acid rinsing tank is connected to the inlet of the wastewater storage tank via a pipeline.

[0011] Furthermore, the acid concentration monitoring device is a conductivity analyzer.

[0012] Furthermore, the water quality monitoring device is a resistivity analyzer.

[0013] Advantages of this utility model: First, by directing the high-concentration waste acid generated from silicon block pickling to the main etching process of silicon cores, where acid purity requirements are lower, the system achieves resource-based, tiered utilization of waste acid. This directly saves on hazardous waste outsourcing costs, reduces the consumption of fresh acid for silicon core cleaning, and lowers the wastewater treatment load. Second, it reduces the total amount of waste acid and wastewater generated at the source, alleviating environmental protection pressure and aligning with the concepts of green manufacturing and a circular economy. Simultaneously, the system uses waste acid for primary etching and high-purity acid for reinforcement etching, combined with final-stage fresh ultrapure water rinsing, effectively preventing secondary contamination of the silicon cores by impurities in the waste liquid, ensuring that the final cleanliness of the silicon cores meets requirements. Furthermore, by organically coupling the previously isolated silicon blocks with the silicon core cleaning line, the system optimizes the material and chemical flow within the factory, improving resource utilization efficiency and the level of intelligence in the production process. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the system connection in this embodiment.

[0015] In the diagram: Silicon block cleaning unit 1, silicon block alkaline washing tank 11, silicon block alkaline rinsing tank 12, silicon block acid pickling assembly 13, silicon block acid mixing tank 131, silicon block acid pickling tank 132, waste acid buffer tank 133, silicon block acid rinsing assembly 14, silicon block acid rinsing tank 141, wastewater buffer tank 142, silicon block drying tank 15, silicon core cleaning unit 2, silicon core alkaline washing tank 21, silicon core alkaline rinsing tank 22, silicon core acid pickling assembly 23, main etching. Tank 231, Reinforcing Etching Tank 232, Waste Acid Storage Tank 233, Silicon Core Acid Mixing Tank 234, Silicon Core Acid Rinsing Assembly 24, Silicon Core Acid Rinsing Tank 241, Wastewater Storage Tank 242, Silicon Core Drying Tank 25, Waste Liquid Utilization Unit 3, Waste Acid Transport Pipeline 31, First Flow Control Valve 32, Conductivity Analyzer 33, Wastewater Transport Pipeline 34, Second Flow Control Valve 35, Resistivity Analyzer 36, Ultrapure Water Storage Tank 4. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Example 1 like Figure 1 The system shown is a combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores, including a silicon block cleaning unit 1, a silicon core cleaning unit 2, and a waste liquid utilization unit 3. The silicon block cleaning unit 1 includes a silicon block alkaline washing tank 11, a silicon block alkaline rinsing tank 12, a silicon block acid washing assembly 13, a silicon block acid rinsing assembly 14, and a silicon block drying tank 15 arranged sequentially along the process flow. The silicon core cleaning unit 2 includes a silicon core alkaline washing tank 21, a silicon core alkaline rinsing tank 22, a silicon core acid washing assembly 23, a silicon core acid rinsing assembly 24, and a silicon core drying tank 25 arranged sequentially along the process flow. Waste liquid utilization unit 3 includes a waste acid conveying pipeline 31 and a wastewater conveying pipeline 34. The two ends of the waste acid conveying pipeline 31 are respectively connected to the outlet of the waste acid buffer tank 133 of the silicon block acid washing assembly 13 and the inlet of the silicon core acid washing tank of the silicon core acid washing assembly 23. A first flow control valve 32 and an acid concentration monitoring device are installed on the waste acid conveying pipeline 31. The acid concentration monitoring device is a conductivity analyzer 33. The two ends of the wastewater conveying pipeline 34 are respectively connected to the outlet of the wastewater buffer tank 142 of the silicon block acid rinsing assembly 14 and the inlet of the silicon core acid rinsing tank 241 of the silicon core acid rinsing assembly 24. A second flow control valve 35 and a water quality monitoring device are installed on the wastewater conveying pipeline 34. The water quality monitoring device is a resistivity analyzer 36.

[0018] Specifically, the silicon block pickling assembly 13 includes a silicon block acid mixing tank 131 and at least two silicon block pickling tanks 132 arranged in series along the process flow. The outlet of the silicon block acid mixing tank 131 is connected to the inlet of the last silicon block pickling tank 132 via a pipeline. The outlets of the silicon block pickling tanks 132 other than the first-stage silicon block pickling tank 132 are all connected to the inlet of the silicon block pickling tank 132 preceding it. The outlet of the first-stage silicon block pickling tank 132 is connected to the inlet of the waste acid storage tank 233 via a pipeline.

[0019] The silicon core pickling assembly 23 includes a main etching tank 231; the outlet of the waste acid buffer tank 133 is connected to the inlet of the main etching tank 231 through the waste acid conveying pipeline 31, and the outlet of the main etching tank 231 is connected to the inlet of the waste acid storage tank 233 through a pipeline.

[0020] The silicon core acid washing assembly 23 also includes a silicon core acid mixing tank 234 and a reinforcing etching tank 232 disposed after the main etching tank 231 along the process flow; the outlet of the silicon core acid mixing tank 234 is connected to the inlet of the reinforcing etching tank 232 through a pipeline, and the outlet of the reinforcing etching tank 232 is connected to the inlet of the main etching tank 231 through a pipeline.

[0021] The silicon block acid rinsing assembly 14 includes at least three silicon block acid rinsing tanks 141 arranged sequentially along the process flow. The inlets of the silicon block acid rinsing tanks 141, except for the last silicon block acid rinsing tank 141, are connected to the outlets of the silicon block acid rinsing tanks 141 that follow the last stage. The outlets of the silicon block acid rinsing tanks 141, except for the first stage silicon block acid rinsing tank 141, are connected to the inlets of the silicon block acid rinsing tanks 141 that precede the first stage. The outlet of the first stage silicon block acid rinsing tank 141 is connected to the inlet of the wastewater buffer tank 142 via a pipeline. The outlet of the ultrapure water storage tank 4 is connected to the inlet of the final stage silicon block acid rinsing tank 141 via a pipeline.

[0022] The silicon core acid rinsing assembly 24 includes at least three silicon core acid rinsing tanks 241 arranged sequentially along the process flow. The outlet of the last silicon core acid rinsing tank 241 is connected to the inlet of the second-to-last silicon core acid rinsing tank 241 via a pipeline. The outlet of the wastewater buffer tank 142 is connected to the inlet of the second-to-last silicon core acid rinsing tank 241 via a wastewater conveying pipeline 34. The outlet of the second-to-last silicon core acid rinsing tank 241 is connected to the inlet of the silicon core acid rinsing tank 241 preceding it. The outlet of the first silicon core acid rinsing tank 241 is connected to the inlet of the wastewater storage tank 242. The outlet of the ultrapure water storage tank 4 is connected to the inlet of the last silicon core acid rinsing tank 241 via a pipeline. The outlet of the first silicon core acid rinsing tank 241 is connected to the inlet of the wastewater storage tank 242 via a pipeline.

[0023] Job Description: In this embodiment, several silicon blocks from the same batch are placed in a PFA basket, and the silicon block handling robot grabs the PFA basket and passes it sequentially through the silicon block alkaline washing tank 11, the silicon block alkaline rinsing tank 12, two counter-current silicon block acid washing tanks 132, three counter-current silicon block acid rinsing tanks 141, and the silicon block drying tank 15; and several silicon cores from the same batch are placed in a squirrel-cage fixture, and the silicon core handling robot grabs the squirrel-cage fixture and passes it sequentially through the silicon core alkaline washing tank 21, the silicon core alkaline rinsing tank 22, the main etching tank 231, the reinforcing etching tank 232, three silicon core acid rinsing tanks 241, and the silicon core drying tank 25.

[0024] Specifically, the silicon blocks in the PFA basket are first treated with alkaline solution in the silicon block alkaline washing tank 11, and then rinsed with pure water in the silicon block alkaline rinsing tank 12 to remove residual alkaline solution from the surface of the silicon blocks. Next, they are sequentially etched in the first-stage silicon block acid washing tank 132 for 10 minutes and the second-stage silicon block acid washing tank 132 for 8 minutes to complete the acid washing treatment. Then, they are sequentially rinsed in the first-stage silicon block acid rinsing tank 141, the second-stage silicon block acid rinsing tank 141 and the third-stage silicon block acid rinsing tank 141 to remove residual acid from the surface of the silicon blocks. Finally, they are placed in the silicon block drying tank 15, thus completing the cleaning of the silicon blocks.

[0025] The silicon cores in the cage fixture are first treated with alkaline solution in the silicon core alkaline washing tank 21, and then rinsed with pure water in the silicon core alkaline rinsing tank 22 to remove residual alkaline solution from the surface of the silicon cores. Next, they are acid-washed in the main etching tank 231. Three silicon cores are randomly sampled from the cage fixture after acid washing in the main etching tank 231, and their surface metal content is tested. If the surface metal content test results of the three sampled silicon cores all meet the expected cleaning effect, it is determined that the acid washing has met the standard. Therefore, there is no need to enter the reinforcement etching tank 232 for secondary acid washing with high-purity acid. Instead, they directly enter the first-stage silicon core acid rinsing tank 241, the second-stage silicon core acid rinsing tank 241, and the third-stage silicon core acid rinsing tank 241 to complete the rinsing of residual acid solution from the surface of the silicon cores. Finally, they enter the silicon core drying tank 25, thus completing the cleaning of the silicon cores. If the surface metal content test results of the three sampled silicon cores do not all meet the expected cleaning effect, it is determined that the acid washing is not up to standard. In this case, they need to enter the reinforcement etching tank 232 for secondary acid washing with high-purity acid, and then enter the first-stage silicon core acid rinsing tank 241, the second-stage silicon core acid rinsing tank 241 and the third-stage silicon core acid rinsing tank 241, and finally enter the silicon core drying tank 25.

[0026] In the above process, the silicon blocks are subjected to secondary etching in the second-stage silicon block pickling tank 132 using a mixed acid solution with a volume ratio of HNO3:HF:H2O = 1:3:12. The etching time is about 10 minutes, and the total etching depth is about 5μm. After etching, the concentration of waste acid generated in the second-stage silicon block pickling tank 132 decreases to about 60% of the original concentration. The waste acid then enters the first-stage silicon block pickling tank 132 for preliminary pickling and etching of the silicon blocks. The waste acid generated in the first-stage silicon block pickling tank 132 enters the waste acid conveying pipeline 31. After being temporarily stored in the acid buffer tank 133, the silicon core is initially acid-etched in the main etching tank 231, thereby reusing the waste acid. At the same time, the fresh mixed acid solution in the reinforcing etching tank 232 enhances the etching of the silicon core to ensure the acid-washing effect. The waste acid generated in the reinforcing etching tank 232 is returned to the main etching tank 231 to reinforce the acid concentration in the main etching tank 231, thereby improving the acid-washing effect of the main etching tank 231 and reducing the amount of fresh mixed acid solution used in the reinforcing etching tank 232.

[0027] In addition, the fresh ultrapure water with a resistivity ≥18.2MΩ·cm in the ultrapure water storage tank 4 enters the third-stage silicon block acid rinsing tank 141 and the third-stage silicon core acid rinsing tank 241 for final fine rinsing to ensure surface cleanliness and ensure that surface impurity ions of the silicon blocks after rinsing in the third-stage silicon block acid rinsing tank 141 and the silicon cores after rinsing in the third-stage silicon core acid rinsing tank 241 can be completely removed. After that, the rinsing wastewater flows back to the corresponding second-stage rinsing tank to perform a second rinsing on the silicon blocks and silicon cores respectively. Then, the wastewater in the second-stage silicon block acid rinsing tank 141 flows back to the first-stage silicon block acid rinsing tank 141 to perform a preliminary rinsing on the silicon blocks and remove most of the acid attached to the surface of the silicon blocks. Wastewater from the first-stage silicon block acid rinsing tank 141 is temporarily stored in the wastewater buffer tank 142 before entering the second-stage silicon core acid rinsing tank 241. Wastewater generated in the second-stage silicon core acid rinsing tank 241 flows back to the first-stage silicon core acid rinsing tank 241 for primary rinsing of the silicon core, removing most of the acid adhering to the surface of the silicon core.

[0028] In this embodiment, the conductivity of the waste acid entering the waste acid buffer tank 133 is detected by the conductivity analyzer 33 on the waste acid conveying pipeline 31 to indirectly reflect the concentration of the waste acid; and the resistivity of the waste acid entering the waste water buffer tank 142 is detected by the resistivity analyzer 36 on the waste water conveying pipeline 34 to indirectly reflect the cleanliness of the waste water; when the detected values ​​fail to meet the corresponding preset thresholds, the valve openings of the first flow control valve 32 and the second flow control valve 35 are adjusted to control the conveying volume of waste acid and waste water, and fresh high-purity acid and ultrapure water are added to meet the cleaning requirements.

[0029] In this embodiment, the waste acid and primary rinsing water generated from the cleaning of silicon blocks, which no longer meet the high cleanliness requirements of the silicon blocks themselves, are used in a targeted and controllable manner in the silicon core cleaning process where the requirements for the cleaning medium are lower. This significantly reduces the cost of hazardous waste treatment and the consumption of fresh high-purity chemicals, achieves the cascade utilization of resources, alleviates environmental pressure, and ensures that the cleaning quality of the silicon cores is fully qualified through precise process control.

[0030] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores, characterized in that, It includes a silicon block cleaning unit, a silicon core cleaning unit, and a waste liquid utilization unit; The silicon block cleaning unit includes a silicon block alkaline washing tank, a silicon block alkaline rinsing tank, a silicon block acid washing assembly, a silicon block acid rinsing assembly, and a silicon block drying tank arranged sequentially along the process flow. The silicon core cleaning unit includes a silicon core alkaline washing tank, a silicon core alkaline rinsing tank, a silicon core acid washing assembly, a silicon core acid rinsing assembly, and a silicon core drying tank arranged sequentially along the process flow. The waste liquid utilization unit includes a waste acid conveying pipeline and a wastewater conveying pipeline. The two ends of the waste acid conveying pipeline are respectively connected to the outlet of the waste acid buffer tank of the silicon block pickling assembly and the inlet of the silicon core pickling tank of the silicon core pickling assembly. A first flow control valve and an acid concentration monitoring device are installed on the waste acid conveying pipeline. The two ends of the wastewater conveying pipeline are respectively connected to the outlet of the wastewater buffer tank of the silicon block acid rinsing assembly and the inlet of the silicon core acid rinsing tank of the silicon core acid rinsing assembly. A second flow control valve and a water quality monitoring device are installed on the wastewater conveying pipeline.

2. The combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores according to claim 1, characterized in that, The silicon block pickling assembly includes a silicon block acid mixing tank and at least two silicon block pickling tanks arranged in series along the process flow. The outlet of the silicon block acid mixing tank is connected to the inlet of the last silicon block pickling tank via a pipeline. The outlets of the silicon block pickling tanks other than the first-stage silicon block pickling tank are connected to the inlets of the silicon block pickling tanks preceding them. The outlet of the first-stage silicon block pickling tank is connected to the inlet of the waste acid storage tank via a pipeline.

3. The combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores according to claim 1, characterized in that, The silicon core pickling assembly includes a main etching tank; the outlet of the waste acid buffer tank is connected to the inlet of the main etching tank through the waste acid conveying pipeline, and the outlet of the main etching tank is connected to the inlet of the waste acid storage tank through a pipeline.

4. The combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores according to claim 3, characterized in that, The silicon core acid washing assembly also includes a silicon core acid mixing tank and a reinforcing etching tank disposed along the process flow after the main etching tank; the outlet of the silicon core acid mixing tank is connected to the inlet of the reinforcing etching tank through a pipeline, and the outlet of the reinforcing etching tank is connected to the inlet of the main etching tank through a pipeline.

5. The combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores according to claim 1, characterized in that, The silicon block acid rinsing assembly includes at least three silicon block acid rinsing tanks arranged sequentially along the process flow. The inlets of all silicon block acid rinsing tanks except the last one are connected to the outlets of the silicon block acid rinsing tanks following the last one. The outlets of all silicon block acid rinsing tanks except the first one are connected to the inlets of the silicon block acid rinsing tank preceding the first one. The outlet of the first-stage silicon block acid rinsing tank is connected to the inlet of the wastewater buffer tank via a pipeline. The outlet of the ultrapure water storage tank is connected to the inlet of the final stage silicon block acid rinsing tank via a pipeline.

6. The combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores according to claim 1, characterized in that, The silicon core acid rinsing assembly includes at least three silicon core acid rinsing tanks arranged sequentially along the process flow. The outlet of the last-stage silicon core acid rinsing tank is connected to the inlet of the second-to-last-stage silicon core acid rinsing tank via a pipeline. The outlet of the wastewater buffer tank is connected to the inlet of the second-to-last-stage silicon core acid rinsing tank via a wastewater conveying pipeline. The outlet of the second-to-last-stage silicon core acid rinsing tank is connected to the inlet of the silicon core acid rinsing tank preceding it. The outlet of the first-stage silicon core acid rinsing tank is connected to the inlet of the wastewater storage tank. The outlet of the ultrapure water storage tank is connected to the inlet of the final stage silicon core acid rinsing tank via a pipeline; the outlet of the first stage silicon core acid rinsing tank is connected to the inlet of the wastewater storage tank via a pipeline.

7. The combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores according to claim 1, characterized in that, The acid concentration monitoring device is a conductivity analyzer.

8. The combined cleaning system for electronic-grade polycrystalline silicon blocks and silicon cores according to claim 1, characterized in that, The water quality monitoring device is a resistivity analyzer.

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