Cleaning equipment and impurity removal processes used in the production of synthetic diamonds

Abstract

This invention belongs to the field of diamond cleaning technology, specifically a cleaning equipment and impurity removal process applied to the production of synthetic diamonds. It includes a vertical cleaning vessel with a central cathode rod and a circumferential anode ring to create a radial electrolytic field. A jetting suspension assembly is located at the bottom to create a circulating flow field for the diamond particles. The core component is a scanning and vibration unit, which includes a ring-shaped ultrasonic transducer coaxially mounted outside the central cathode rod. The transducer has a scraper ring inside its bore and is driven by a drive mechanism to reciprocate along the Z-axis within the slurry. The process includes feeding and jetting, hydrogen-induced explosion pretreatment, dynamic mechanical-acoustic-electric synergistic cleaning, online bubble flotation, and sedimentation discharge. This invention solves the problems of traditional bottom-mounted ultrasonic cleaning failing to penetrate thick powder layers and electrode scaling. By eliminating cleaning dead zones through flow field suspension and dynamic scanning, it achieves efficient and deep purification of synthetic diamond micropowder.

Description

Technical Field

[0001] This invention belongs to the field of diamond cleaning technology, specifically to cleaning equipment and impurity removal processes applied to the production of synthetic diamonds. Background Technology

[0002] Currently, the high-temperature, high-pressure (HPHT) method is mainly used in industry to synthesize diamond using graphite as a carbon source in a six-sided press, under the action of a catalyst alloy. However, the synthesized product is not a pure diamond crystal, but a complex mixture. The impurities mainly originate from three aspects: unconverted carbon source: the surface of the synthesized rod and the spaces between grains contain a large amount of unconverted graphite and loosely structured amorphous carbon; metal catalyst residue: to reduce the activation energy required for synthesis, transition metal alloys such as nickel (Ni), manganese (Mn), cobalt (Co), or iron (Fe) are used extensively as catalysts. These metals often exist in the interstices of diamond crystals as inclusions, fillers, or surface adhesions; pressure-transmitting medium contamination: during the crushing and separation of the synthesized rod, ceramic pressure-transmitting medium powders such as pyrophyllite and dolomite can also mix into the diamond micropowder. If these impurities are not completely removed, they will seriously affect the purity, color, magnetism, and bonding strength of the diamond product. Therefore, purification is a crucial step in the production of synthetic diamonds.

[0003] Existing purification processes mainly rely on a combination of chemical oxidation and strong acid washing. The common practice is to place the crushed diamond rough in the main body of the washing vessel (1), add concentrated sulfuric acid, concentrated nitric acid or perchloric acid, and use the strong oxidizing properties of the acid at high temperature to oxidize the graphite into carbon dioxide gas and discharge it, while dissolving the metal catalyst into an ionic state. Finally, the graphite is removed by washing with water. However, this traditional chemical treatment method has obvious limitations: on the one hand, the amount of strong acid used is large, which not only results in high production costs, but also generates a large amount of difficult-to-treat acidic waste liquid and nitrogen oxide waste gas, resulting in a huge environmental pollution load; on the other hand, for fine particles tightly wrapped by the graphite layer or metal impurities hidden deep in the intergranular gaps, simple static chemical soaking is difficult to penetrate, resulting in incomplete reaction and a long purification cycle.

[0004] To improve cleaning efficiency, ultrasonic cleaning technology has been introduced as an auxiliary method in the industry. Existing ultrasonic cleaning equipment mostly adopts a bottom-vibration structure, where the ultrasonic transducer array is installed at the bottom of the cleaning tank. The cleaning fluid acts as a medium to transmit the cavitation effect, and the shock waves generated by the collapse of cavitation bubbles remove surface dirt. However, this equipment structure faces unique physical challenges when applied to cleaning diamond micropowder. Due to the high density of diamond, far exceeding that of the cleaning fluid and suspended graphite impurities, it easily settles and accumulates rapidly at the bottom of the tank during the cleaning process. When the accumulation layer reaches a certain thickness, the dense diamond powder layer at the bottom generates strong acoustic attenuation and shielding effects on the ultrasonic waves emitted by the bottom transducer. This leads to two serious technical problems: hindered energy transmission—the ultrasonic energy is mainly consumed by frictional heating of the bottom deposit layer, making it difficult to penetrate the thick powder layer to reach the upper liquid. This results in extremely weak cavitation intensity in the upper and central areas of the tank, failing to effectively disperse suspended graphite and fine particles, creating cleaning "dead zones." Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention proposes a cleaning equipment and impurity removal process for synthetic diamond production. This invention primarily addresses the problem that conventional bottom-vibration ultrasonic waves are insufficient to penetrate thick powder layers during ultrasonic cleaning of synthetic diamonds, resulting in incomplete cleaning of the upper and central areas.

[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: According to the first aspect of the present invention, a cleaning device for the production of synthetic diamonds includes a cleaning vessel body and an ultrasonic transducer disposed therein; the cleaning vessel body is a vertical acid-resistant container, the structure of which includes an upper straight cylindrical section and a lower gravity settling inverted cone; The electrochemical assembly includes a central cathode rod suspended vertically along the main axis of the cleaning vessel and a circumferential anode ring attached to the inner wall of the straight section, which together form a radial electrolysis field. A jet-driven suspension assembly includes a jet-driven ring pipe located at the bottom of the interior of the cleaning vessel body and a circulation loop connecting the assembly to the liquid inlet at the top of the cleaning vessel body, used to construct a jet-driven circulating flow field that causes diamond particles to rise along the center. The sweeping and vibration unit includes an annular ultrasonic transducer coaxially sleeved around the central cathode rod and located inside the circumferential anode ring, and a drive mechanism that drives it to reciprocate along the Z-axis within the slurry. Bottom discharge assembly; located at the bottom of the gravity settling inverted cone, used to discharge the cleaned synthetic diamonds.

[0007] Preferably, a scraper ring is provided on the inner side of the housing of the ultrasonic transducer; The inner diameter of the scraper ring is designed to form an interference fit with the outer diameter of the central cathode rod; As the ultrasonic transducer moves along the Z-axis, the scraper ring mechanically removes the dense metal reduction layer deposited on the surface of the central cathode assembly.

[0008] Preferably, the outer wall surface of the ultrasonic transducer facing the circumferential anode ring is a convex arc surface, which forms an acoustic diverging lens to expand the sound wave radiation angle to cover the particle layer falling along the wall. The inner wall of the ultrasonic transducer facing the central cathode rod is a vertical cylindrical surface, forming a non-focused acoustic interface for generating plane waves. The piezoelectric ceramic array encapsulated inside the ultrasonic transducer is divided into an outer array group and an inner array group; the number of outer array groups is greater than the number of inner array groups, and the ratio of the two is selected from the range of 2:1 to 4:1.

[0009] Preferably, the jetting ring pipe has several jet nozzles evenly distributed along the circumference; The axis of the nozzle points to the central axis of the container and is tilted upward relative to the horizontal plane, with the tilt angle ranging from 30° to 60°.

[0010] Preferably, the circulation loop includes a bubble generator connected in series in the loop; the bubble generator draws in gas by utilizing the pressure drop of the fluid passing through the throat and generates micro- and nano-bubbles by utilizing hydraulic shear. An overflow trough is provided on the top of the main body of the cleaning tank, and the overflow trough is connected to the waste liquid collection pipeline.

[0011] Preferably, the drive mechanism includes a movable frame that is slidably connected to the main body of the cleaning vessel; a hydraulic cylinder is fixedly connected to the main body of the cleaning vessel, and one end of the movable rod of the hydraulic cylinder is fixedly connected to the movable frame; a ring frame is provided at the lower part of the movable frame; an ultrasonic transducer is rotatably connected to the ring frame; and an inclined drive plate is provided on the inner side of the ultrasonic transducer. According to a second aspect of the present invention, a cleaning and impurity removal process for the production of synthetic diamonds includes the following steps: S1 Feeding and Spraying: Inject the medium, start the external circulation, and use the rising flow generated by the spraying ring pipe to establish the "center rise - wall fall" circulation flow of diamond particles; S2 hydrogen-induced explosion pretreatment: Before turning on the ultrasonic waves, a high instantaneous current density or reverse voltage is applied to the electrode system to generate hydrogen gas in the micropores on the cathode and the surface of the diamond particles. The expansion pressure of hydrogen gas evolution is used to destroy the dense carbon film covering the diamond. S3 Dynamic Machine-Acoustic-Electrical Synergistic Cleaning: Turn on the ultrasonic and electrolytic power supply, control the ring transducer to perform Z-axis scanning, and simultaneously use mechanical scraper and ultrasonic field to perform the operation; S4 Sedimentation and Discharge: Stop the circulation and functional field, and wait for the particles to completely settle into the inverted cone under gravity before opening the bottom discharge component to discharge the finished product.

[0012] Preferably, in step S3, the transducer is controlled to move upward at a speed greater than 50 mm / s; and the transducer is controlled to move downward at a speed less than 10 mm / s.

[0013] Preferably, the asymmetric pulsed current applied in step S3 includes a high-voltage, long-cycle oxidation-dissolution period and a low-voltage, short-cycle desorption-repulsion period.

[0014] Preferably, between step S3 and step S4, a further step S3-B is provided: after the impurity removal is completed, while keeping the electrolyte in the main body of the cleaning vessel unchanged, the current density of the DC power supply is increased to 0.3 A / cm². 2 Up to 0.8A / cm 2 High oxygen evolution range; switch the annular ultrasonic transducer to high frequency mode, setting the frequency to 80kHz to 120kHz; control the slurry temperature inside the cleaning tank body between 40℃ and 60℃.

[0015] The beneficial effects of this invention are as follows: 1. In this invention, an ordered circulating flow field of "rising from the center and falling back along the wall" is constructed through a jet-driven suspension component. This utilizes fluid dynamics to break the sedimentation and accumulation of high-density diamond powder at the bottom of the vessel, ensuring all particles are in a suspended fluidized state. Combined with the Z-axis dynamic scanning motion of a ring-shaped ultrasonic transducer, the "static sound field" is transformed into a "dynamic tracking sound field," actively scanning particle layers suspended at different heights. This completely eliminates the sound field dead zones caused by powder layer shielding in traditional bottom-vibration equipment, ensuring that each diamond receives powerful acoustic-electric synergistic treatment and improving the uniformity of cleaning.

[0016] 2. This invention utilizes the existing Z-axis reciprocating motion of the vibration sweeping unit as a power source, and achieves real-time physical scraping of the central cathode rod through an interference-fit scraper ring with an inner hole. Without the need for an additional drive mechanism, it achieves "cleaning the product while cleaning the electrode," ensuring the cathode surface remains in a clean metallic state, preventing increased resistance and current efficiency decay, and significantly extending the continuous operating cycle of the equipment.

[0017] 3. In terms of process, this invention introduces a "hydrogen-induced explosion pretreatment," which utilizes the instantaneous expansion pressure of hydrogen gas generated by electrolysis within micron-sized pores to physically break through the dense carbon film and metal passivation layer encapsulating the diamond surface. This opens channels for subsequent acid penetration, significantly improving the removal rate of stubborn impurities. Simultaneously, in conjunction with an asymmetric pulsed commutation current, the electrostatic repulsion of the reverse electric field effectively prevents the secondary adsorption of dissolved metal ions on the diamond surface, maximizing product purity.

[0018] 4. By integrating a bubble generator into the circulation loop, micro- and nano-bubbles are generated using hydraulic cavitation to selectively capture hydrophobic graphite and carbon slag, which are then discharged from the system in real time through a top overflow trough. This "washing and discharging simultaneously" mode avoids back-contamination of impurities during shutdown settling. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the first overall structure installation of the cleaning equipment in this invention; Figure 2 This is a schematic diagram of the second overall structure installation of the cleaning equipment in this invention; Figure 3 This is a schematic diagram of the first internal structure of the cleaning equipment in this invention; Figure 4 This is a schematic diagram of the second internal structure of the cleaning equipment in this invention; Figure 5 This is a schematic diagram of the first internal structure of the ultrasonic transducer in this invention; Figure 6 This is a schematic diagram of the second internal structure of the ultrasonic transducer in this invention; Figure 7 This is a schematic diagram of the installation structure of the inclined plate in this invention; Figure 8 This is a schematic diagram of the jet-driven circulating flow field in this invention; Figure 9 This is a schematic diagram of the convex arc surface of the ultrasonic transducer in this invention; Figure 10 This is a schematic diagram of the pulse power supply involved in step S3 of the present invention; In the diagram: 1. Cleaning vessel body; 2. Ultrasonic transducer; 3. Straight cylindrical section; 4. Gravity settling inverted cone; 5. Central cathode rod; 6. Circumferential anode ring; 7. Spraying ring pipe; 8. Circulation loop; 9. Scraper ring; 10. Outwardly convex arc surface; 11. Vertical cylindrical surface; 12. Outer array group; 13. Inner array group; 14. Spray nozzle; 15. Bubble generator; 16. Overflow trough; 17. Movable frame; 18. Hydraulic cylinder; 19. Ring frame; 20. Drive plate. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0022] Equipment Example 1: like Figures 1 to 3As shown, a cleaning device for the production of synthetic diamonds includes a cleaning vessel body 1 and an ultrasonic transducer 2 disposed therein; the cleaning vessel body 1 is a vertical acid-resistant container, the structure of which includes an upper straight cylindrical section 3 and a lower gravity settling inverted cone 4. The electrochemical assembly includes a central cathode rod 5 suspended vertically along the central axis of the main body 1 of the cleaning vessel, and a circumferential anode ring 6 attached to the inner wall of the straight section, which together form a radial electrolysis field. The jet suspension assembly includes a jet ring pipe 7 located at the bottom of the interior of the cleaning vessel body 1 and a circulation loop 8 connecting the assembly to the liquid intake port at the top of the cleaning vessel body 1, which is used to construct a jet circulation flow field that causes diamond particles to rise along the center. The sweeping and vibration unit includes an annular ultrasonic transducer 2 coaxially sleeved around the central cathode rod 5 and located inside the circumferential anode ring 6, and a drive mechanism that drives it to reciprocate along the Z-axis in the slurry. Bottom discharge assembly; located at the bottom of the gravity settling inverted cone 4, used to discharge the cleaned synthetic diamonds.

[0023] In the initial operating state of the equipment, the cleaning vessel body 1 is filled with a mixture of diamond and inclined liquid. Subsequently, the circulation loop 8 is activated, and the cleaning liquid is injected at high speed through the jetting ring pipe 7 located at the bottom of the cleaning vessel body. Due to the high specific gravity of diamond powder (approximately 3.5 g / cm³), the cleaning solution is applied. 3 Ordinary stirring is insufficient to achieve uniform suspension. This solution utilizes the jet from the spray ring pipe 7 to create a powerful upward surge at the center of the cleaning vessel, carrying particles towards the liquid surface. After reaching the top, the particles' kinetic energy diminishes, causing them to diffuse outwards and slowly fall back along the inner wall of the straight section 3, eventually converging again at the bottom to be sprayed, forming an orderly "center up, surrounding down" circulating flow field. This solves the problem of dead zones in material deposition and improves the uniformity of material cleaning.

[0024] While the particles are circulating, the coaxially arranged electrochemical components (cathode rod and anode ring) in the main body of the cleaning vessel 1 create a uniform radial electric field throughout the reaction chamber, which electrolytically oxidizes and cleans the particles flowing through it.

[0025] The driving mechanism of the cleaning vessel body 1 drives the annular ultrasonic transducer 2 to reciprocate up and down in the Z-axis direction, achieving "dynamic scanning". Due to the height limitation of the cleaning vessel body 1, a fixed ultrasonic transducer cannot cover the entire area and is prone to standing wave dead zones. The annular ultrasonic transducer 2 actively acts on the particle layers suspended at different heights, ensuring that each diamond is within the strong ultrasonic radiation zone.

[0026] After cleaning is completed, the jetting circulation and sweeping vibration of the main body 1 of the cleaning tank stop. Gravity causes the diamond particles to naturally converge towards the gravity settling inverted cone 4. Opening the bottom discharge component allows for the rapid discharge of high-concentration slurry, minimizing material residue.

[0027] Impurity metal catalysts on diamond typically exist as inclusions or interstitial fillers, and easily form a passivation layer on the surface during pickling. This technical solution utilizes a moving ultrasonic transducer 2 to directly apply the cavitation effect of ultrasound to the region where the electrolytic reaction is most intense. The shock waves generated by cavitation can rapidly peel off the passivation layer and reaction products from the metal surface, enhancing the contact mass transfer between the acid and deep metal impurities, thereby solving the problem of metal catalysts being "undissolved and incompletely dissolved."

[0028] The liquid inlet is located on the side wall of the straight section of the main body of the cleaning vessel, with its axis positioned 200mm to 400mm below the highest liquid level in the main body of the cleaning vessel. This position is chosen to ensure that the liquid inlet is always in the negative pressure zone below the liquid level, avoiding the intake of impurities and foam from the surface of the liquid into the circulation loop and causing secondary pollution. The inside of the liquid inlet is equipped with a downward-curved suction hood or anti-vortex baffle to change the direction of fluid intake and prevent the formation of suction vortices on the liquid surface due to pump suction.

[0029] like Figure 3 and Figure 4 As shown, the drive mechanism includes a movable frame 17, which is slidably connected to the main body 1 of the cleaning vessel; a hydraulic cylinder 18 is fixedly connected to the main body 1 of the cleaning vessel, and one end of the movable rod of the hydraulic cylinder 18 is fixedly connected to the movable frame 17; a ring frame 19 is provided at the lower part of the movable frame 17; an ultrasonic transducer 2 is rotatably connected to the ring frame 19; and an inclined drive plate 20 is provided on the inner side of the ultrasonic transducer 2.

[0030] During operation, the movement of the movable rod of the hydraulic cylinder 18 drives the movable frame 17 to move in the z-axis direction, thereby driving the ring frame 19 and the ultrasonic transducer 2. The drive plate 20, which is fixedly connected to the inner side of the housing of the ultrasonic transducer 2, generates a tangential force when it moves in the z-axis direction due to its tilted setting, which in turn causes the ultrasonic transducer 2 to rotate. (The tangential force is generated when the transducer moves at high speed along the z-axis in the slurry (especially downward movement) or is impacted by the high-speed jet upward from the bottom jet ring pipe 7, the fluid moves relative to the drive plate 20.) Because the drive plate 20 is inclined (similar to turbine blades), fluid resistance generates a component force perpendicular to the plate surface. This component force can be decomposed into resistance in the Z-axis direction and a horizontal tangential component force. Torque drive: The horizontal tangential component force generated by several drive plates 20 in the main body of the cleaning vessel 1 forms a torque around the central axis, driving the ultrasonic transducer 2 to rotate within the annular frame 19. This achieves rotation of the ultrasonic transducer 2 during its up-and-down movement, thereby making the acoustic wave action of the ultrasonic transducer 2 more uniform in the slurry system, improving the uniformity of cleaning. This technical solution transforms the linear driving force of the Z-axis or the impact force of the fluid into the rotational motion of the ultrasonic transducer 2 through a fluid dynamics structure. This makes the scraping trajectory of the scraper ring 9 on the cathode a spiral (a combination of Z-axis linear motion and circular rotation), resulting in more uniform and thorough scraping. At the same time, it also causes the sound field to rotate continuously in the circumferential direction, further improving the uniformity of the sound field.

[0031] Because the ultrasonic transducer 2 not only moves up and down but also rotates during operation, traditional direct-connection wires would be twisted and broken. Therefore, this solution explicitly states that "a conductive slip ring structure is used for power supply." The conductive slip ring is installed at the connection between the transducer and the ring frame 19, with the stator end connected to the power supply and the rotor end connected to the transducer, ensuring uninterrupted transmission of high-frequency electrical energy during rotation.

[0032] The hydraulic cylinder 18, fixed externally to the main body 1 of the cleaning vessel, is the main power source. The hydraulic system features high thrust and smooth operation, making it suitable for driving heavy structures. When the movable rod of the hydraulic cylinder 18 extends or retracts, it directly drives the movable frame 17 to move up and down along the guide rail (slidably connected to the vessel body) in the Z-axis direction, thereby realizing the lifting and scanning motion of the ultrasonic transducer 2.

[0033] The rotation mainly occurs during the high-speed upward phase (e.g., 50-90 mm / s) and when impacted by the high-speed jet from the bottom jetting ring; rotation does not mainly occur during the low-speed downward phase.

[0034] Equipment Example 2: like Figure 5 and Figure 6As shown, the outer wall surface of the ultrasonic transducer 2 facing the circumferential anode ring 6 is an outwardly convex arc surface 10, which constitutes an acoustic diverging lens to expand the sound wave radiation angle to cover the particle layer falling along the wall. The inner wall of the ultrasonic transducer 2 facing the central cathode rod 5 is a vertical cylindrical surface 11, which forms a non-focused acoustic interface for generating plane waves. The piezoelectric ceramic array encapsulated inside the ultrasonic transducer 2 is divided into an outer array group 12 and an inner array group 13; the number of outer array groups 12 is greater than the number of inner array groups 13, and the ratio of the two is selected from the range of 2:1 to 4:1.

[0035] Figure 9 The outer side (convex surface) is shown: Sound waves emitted by the ultrasonic transducer diffuse as they pass through the outer surface (according to the law of acoustic refraction, when sound waves travel from a solid medium with a higher sound velocity (such as titanium alloy) to a liquid medium with a lower sound velocity, divergence and refraction occur at the convex interface. This convex arc surface acts as an "acoustic diverging lens"). The convex titanium alloy wall transforms the narrow beam originally emitted perpendicular to the transducer surface into a fan-shaped diverging beam with a wider radiation angle after being acted upon by the lens. This allows the sound waves to cover the vast "wall-falling zone" around the main body of the cleaning vessel, effectively cleaning the slow-flowing, high-concentration particle layer.

[0036] Figure 9 The inner side (vertical plane) shown: The vertical plane or cylindrical surface of the cleaning vessel body 1 generates plane waves or waves with extremely low divergence. Because the inner side is very close to the cathode, if a concave focusing surface is used, the acoustic energy will converge at a certain point on the cathode surface, producing extremely strong cavitation corrosion (pitting). The vertical plane design is adopted to ensure that the acoustic wave energy is evenly distributed, serving only as an auxiliary cleaning function rather than a destructive stripping.

[0037] Power density distribution principle: Due to the geometric characteristics of the annular structure of the cleaning vessel body 1, the outer space has a large volume, while the inner space has a small volume. If the power is the same on both sides, the energy density on the inner side will be too high. By limiting the ratio of piezoelectric ceramics (e.g., 16 outer pieces and 4 inner pieces), a "weak inside and strong outside" power distribution is forced in the hardware. This ensures that while thoroughly cleaning a large amount of material on the periphery, the central cathode rod 5 is protected to the maximum extent from being broken or corroded by the sound waves.

[0038] like Figure 3 and Figure 8 As shown, the jet ring pipe 7 has several jet nozzles 14 evenly distributed along the circumference; The axis of the nozzle 14 points to the central axis of the container and is tilted upward relative to the horizontal plane, with the tilt angle ranging from 30° to 60°.

[0039] During operation, the tilted setting of the nozzle 14 is designed to decompose the fluid momentum into two components: a vertical component (upward): the cleaning vessel body 1 is used to overcome the gravity of the diamond particles and provide the lift required for suspension. If the angle is too small (e.g., 0° horizontally), the fluid directly impacts the particles, failing to effectively lift them and causing material accumulation at the bottom. The horizontal component (centripetal): the cleaning vessel body 1 is used to push the particles from the surrounding area towards the central region, forming a convergence effect and constructing a stable core flow. If the angle is too large (e.g., 90° vertically), it will be unable to entrain material at the bottom edge of the vessel, creating a dead zone. Fluid dynamics simulations and experimental verification have shown that 30° to 60° is the stable range for maintaining the "sprayed bed" flow pattern. Within this range, the fluid can form a strong entrainment effect, preventing particles from depositing below the sprayed ring pipe 7 and ensuring sufficient fluidization of the entire vessel's material.

[0040] Equipment Example 3: like Figures 1 to 3 As shown, the circulation loop 8 includes a bubble generator 15 connected in series in the loop; the bubble generator 15 uses the pressure drop when the fluid passes through the throat to draw in gas and uses hydraulic shearing to generate micro-nano bubbles. An overflow trough 16 is provided on the top of the main body 1 of the cleaning vessel, and the overflow trough 16 is connected to the waste liquid collection pipeline.

[0041] During operation, the microbubble generation mechanism is as follows: The high-pressure fluid provided by the circulating pump to the main body 1 of the cleaning vessel flows through the throat (narrowing section) of the bubble generator 15. The increased flow velocity causes the static pressure to drop to a negative pressure, thereby automatically drawing in air. The high-speed turbulence shears and breaks up the drawn-in air, forming a large number of tiny micro-nano bubbles.

[0042] Microbubbles enter the main body 1 of the cleaning vessel from the bottom along with the slurry. Due to the difference in surface physicochemical properties, the diamond surface is hydrophilic, while the surface of the stripped graphite and amorphous carbon is hydrophobic. Microbubbles selectively capture and adhere to the surface of the hydrophobic graphite particles, forming "bubble-graphite" aggregates.

[0043] Because the apparent density of the polymer is less than that of the liquid, it rises to the surface of the liquid at the top of the cleaning tank body 1, forming a foam layer rich in impurities. As bubbles continue to be generated, the foam accumulates on the liquid surface and overflows the overflow trough 16 at the top of the cleaning tank, flowing into the waste liquid collection pipeline. This achieves an online separation function that "only discharges impurities, not diamonds" during the cleaning process.

[0044] The overflow weir is located at the top opening of the straight section. The top edge of the straight section forms an overflow weir, the height of which defines the highest working liquid level of the main body of the washing tank. During the flotation process, hydrophobic impurities carried by microbubbles accumulate on the liquid surface to form a foam layer. As the liquid level rises, the foam layer overflows the overflow weir and enters the tank, and is discharged from the system through the waste pipe, without entering the circulation loop.

[0045] Equipment Example 4: like Figure 4 and Figure 7 As shown, a scraper ring 9 is provided on the inner side of the housing of the ultrasonic transducer 2; The inner diameter of the scraper ring 9 is designed to form an interference fit with the outer diameter of the central cathode rod 5; When the ultrasonic transducer 2 moves along the Z-axis, the scraper ring 9 mechanically scrapes away the dense metal reduction layer deposited on the surface of the central cathode assembly.

[0046] During operation, in the electrolytic cleaning process, metal ions in the solution move towards the central cathode under the influence of the electric field and are reduced to a spongy metal layer. Scale buildup causes a sharp increase in cathode resistance, reducing cleaning efficiency.

[0047] This solution utilizes the existing "Z-axis reciprocating motion" in the vibration sweeping unit, eliminating the need for an additional power source. The inner diameter of the scraper ring 9 (preferably made of PEEK or ceramic) is slightly smaller than the outer diameter of the cathode rod (e.g., interference fit of 0.1-0.2mm), thereby generating a constant clamping force.

[0048] When the drive mechanism moves the ultrasonic transducer 2 upwards or downwards, the scraper ring 9 generates axial sliding friction relative to the cathode rod surface. The rigid mechanical scraping force directly peels off the highly adhesive metal deposit layer, causing it to detach and precipitate in the solution. This achieves "cleaning and scraping simultaneously," ensuring that the cathode always exposes a clean metal surface after cleaning, maintaining high current density electrolytic reaction conditions, and avoiding downtime for manual cleaning due to excessive scale buildup.

[0049] Process Example 1 A cleaning and impurity removal process for synthetic diamond production includes the following steps: Injecting a prepared electrolyte solution (such as dilute sulfuric acid or a mixed acid solution) into the main body 1 of the cleaning vessel, ensuring the liquid level covers the upper inlet. Turning on the high-pressure circulating pump and adjusting the flow valve to ensure the jet velocity of the bottom jetting ring 7 reaches above the critical fluidization velocity. Then, adding the diamond powder to be cleaned; temporarily turning off the ultrasonic waves. Applying a transient high current (0.8 A / cm²) to the electrode system. 2The process lasts for 60 seconds. Utilizing the expansion force of hydrogen gas evolved on the cathode surface and within the particle gaps, the dense carbon film and metal passivation layer on the diamond surface are physically destroyed. The annular ultrasonic transducer 2 (40kHz, power density 50W / L) is activated. The DC power supply is turned on, employing an asymmetric pulse mode for forward oxidation dissolution for 100ms (voltage 12V) and reverse desorption / repulsion for 10ms (voltage -5V). The Z-axis scanning drive is initiated, with the upward speed set to 60mm / s and the downward speed set to 5mm / s. During this process, a mechanical scraper moves with the transducer, continuously scraping away scale on the cathode surface. The bubble generator 15 is activated, and microbubbles carrying the detached graphite are discharged through the overflow tank 16. After the impurities have been cleaned to the required standard (approximately 3.5 hours), no material is discharged, and the electrolyte level remains unchanged. The power parameters are adjusted: the current density is increased to 0.5A / cm³. 2 (High oxygen evolution zone); Adjust ultrasonic parameters: switch the frequency to 100kHz (high frequency mode); Adjust temperature: control the slurry temperature at 50℃; Processing time: 20 minutes; Stop all functional fields, let stand for 15 minutes, and after the material has completely settled into the inverted cone, start the bottom discharge.

[0050] The working principle of the process: Before activating the ultrasonic waves, maintain fluid circulation and connect the DC power supply. Apply a momentary high current density or a short-term reverse voltage to the electrode system for 30-60 seconds; at this time, a violent electrolytic reaction occurs on the surface of the cathode (or the anode in reverse connection) and within the micropores of the diamond particles. ; Because the dense carbon film (graphite / amorphous carbon) and metal catalyst coating on the diamond surface typically have a porous structure, the hydrogen gas generated by electrolysis rapidly evolves within the confined pores at the micron / nanometer level. The immense physical pressure generated by the instantaneous expansion of the gas within the micropores forces the dense coating to break through from the inside out. This opens a physical channel for subsequent acid penetration and ultrasonic ablation, significantly improving the removal rate of stubborn impurities.

[0051] Adjust the current to the normal electrolytic cleaning parameters, turn on the annular ultrasonic transducer 2, and start the drive mechanism to make it reciprocate along the Z-axis. The ultrasonic waves generate a cavitation effect, physically stripping away surface impurities; the anode generates a strong oxidant to dissolve metal impurities; as the transducer moves along the Z-axis, the scraper ring 9 in the inner hole scrapes away metal deposits on the surface of the central cathode in real time; this achieves "cleaning the product while cleaning the electrode," preventing the electrolytic efficiency from decaying over time and ensuring the continuous stability of the process.

[0052] Turn off the circulation pump, power supply, and ultrasonic waves. Let it stand for a period of time (e.g., 10-20 minutes); the diamonds will gather at the bottom of the inverted cone, while impurities will remain suspended in the upper layer. This inverted cone structure allows for the rapid collection of high-concentration finished products and the initial separation of light impurities.

[0053] The ultrasonic transducer 2 descends slowly, effectively performing a downward-pressing deep cleaning of this high-concentration, slowly moving layer of particles. At this point, the matching degree between the acoustic energy density and the particle density is highest, and the cleaning efficiency reaches its peak.

[0054] In step S3, the DC power supply does not use a constant current, but rather a specific asymmetric pulse waveform, including an oxidation and dissolution period (forward, high voltage, e.g., 100ms): during this period, the central rod acts as the cathode, and the peripheral ring as the anode. The anode generates an oxidizing environment, whose main function is to dissolve the metal catalyst (e.g., Ni oxidizes to Ni). 2+ The desorption repulsion period (reverse, low voltage, such as 5-10ms) is characterized by an instantaneous reversal of polarity, which forcibly "push" the impurity ions that have just dissolved but are trying to re-adsorb into the depths of the solution, causing them to break free from the double layer binding on the particle surface.

[0055] This technical solution achieves the coupling of electric and acoustic fields. Ultrasonic waves physically remove impurities, while a pulsed reverse electric field prevents re-adhesion. The combination of these two technologies overcomes the technical flaw of traditional ultrasonic cleaning where impurities are "washed off and then sucked back up." After routine impurity removal, to improve the hydrophilicity and dispersibility of the diamond micropowder, the following steps can be performed directly without changing equipment: increasing the current density to 0.3-0.8 A / cm². 2 At this current density, the anodic reaction shifts from being dominated by "metal dissolution" to being dominated by "oxygen evolution reaction," generating a large amount of ozone and hydroxyl radicals. The ultrasonic frequency switches to 80-120kHz: the cavitation bubbles generated by high-frequency ultrasound are small in diameter, numerous, and have moderate implosion impact force. It is no longer mainly used for crushing or stripping, but rather as a "microreactor," providing a high-temperature, high-pressure environment to accelerate the chemical reaction; the temperature is controlled at 40-60℃: ensuring the chemical reaction rate while preventing the ozone from decomposing too quickly.

[0056] Driven by high-frequency ultrasound, a high concentration of strong oxidant is forced into the carbon atom lattice on the diamond surface, breaking the surface CH bonds or dangling bonds, and grafting hydrophilic hydroxyl or carboxyl groups in situ; this gives the produced diamond micro powder excellent water dispersibility, eliminating the need for subsequent independent chemical modification processes; system coupling effect: fully utilizing the hardware capabilities of "frequency adjustable ultrasound" and "adjustable power supply" of this equipment, the entire process of "rough washing-fine washing-modification" is continuously completed in the same equipment through the adjustment of software parameters, demonstrating a very high degree of process integration.

[0057] Process Example 2 A cleaning and impurity removal process for synthetic diamond production includes the following steps: Injecting a prepared electrolyte solution (such as dilute sulfuric acid or a mixed acid solution) into the main body 1 of the cleaning vessel, ensuring the liquid level covers the upper inlet. Turning on the high-pressure circulating pump and adjusting the flow valve to ensure the jet velocity of the bottom jetting ring 7 reaches above the critical fluidization velocity. Then, adding the diamond powder to be cleaned; temporarily turning off the ultrasonic waves. Applying a transient high current (0.5 A / cm²) to the electrode system. 2 The process lasts for 45 seconds. Utilizing the expansion force of hydrogen gas evolved on the cathode surface and within the particle gaps, the dense carbon film and metal passivation layer on the diamond surface are physically destroyed. The annular ultrasonic transducer 2 (40kHz, power density 50W / L) is activated. The DC power supply is turned on, employing an asymmetric pulse mode for forward oxidation dissolution for 100ms (voltage 12V) and reverse desorption / repulsion for 10ms (voltage -5V). The Z-axis scanning drive is initiated, using a variable speed strategy: the upward speed is set to 52mm / s, and the downward speed to 8mm / s. During this process, a mechanical scraper moves with the transducer, continuously scraping away scale accumulated on the cathode surface. The bubble generator 15 is activated, and microbubbles carrying the detached graphite are discharged through the overflow tank 16. After the impurities have been cleaned to the required standard (approximately 3.5 hours), no material is discharged, and the electrolyte level remains constant. The power parameters are adjusted: the current density is increased to 0.3A / cm³. 2 Adjust ultrasonic parameters: switch the frequency to 80kHz; adjust the temperature: control the slurry temperature at 40℃; processing time: 20 minutes; stop all functional fields, let stand for 15 minutes, and after the material has completely settled into the inverted cone, start the bottom discharge.

[0058] Process Example 3: A cleaning and impurity removal process for the production of synthetic diamonds includes the following steps: Injecting a prepared electrolyte solution (such as dilute sulfuric acid or a mixed acid solution) into the main body of the cleaning vessel (1), with the liquid level exceeding the upper liquid outlet. Turning on the high-pressure circulating pump and adjusting the flow valve to ensure the jet velocity of the bottom jetting ring pipe 7 reaches above the critical fluidization velocity. Then, adding the diamond micron powder to be cleaned; temporarily turning off the ultrasonic waves. Applying a momentary high current (1.0 A / cm²) to the electrode system. 2 The process lasts for 90 seconds. Utilizing the expansion force of hydrogen gas evolved on the cathode surface and within the particle gaps, the dense carbon film and metal passivation layer on the diamond surface are physically destroyed. The annular ultrasonic transducer 2 (40kHz, power density 50W / L) is activated. The DC power supply is turned on, and an asymmetric pulse mode is used for forward oxidation and dissolution for 100ms (voltage 12V) and reverse desorption and repulsion for 10ms (voltage -5V). The pulse pattern can be configured as follows: Figure 10Provide any one of the three methods a, b, or c; start the Z-axis scanning drive, set the upward speed to 90 mm / s, and the downward speed to 2 mm / s; during this process, the mechanical scraper moves with the transducer, continuously scraping away the scale on the cathode surface; turn on the bubble generator (15), and the microbubbles carry the stripped graphite out through the overflow tank 16; after the impurities are cleaned to the standard (about 3.5 hours), do not discharge the material, and keep the electrolyte unchanged; adjust the power supply parameters: increase the current density to 0.8 A / cm 2 Adjust ultrasonic parameters: switch the frequency to 120kHz; adjust the temperature: control the slurry temperature at 55℃; processing time: 20 minutes; stop all functional fields, let stand for 15 minutes, and after the material has completely settled into the inverted cone, start the bottom discharge.

[0059] Comparative Example 1 The difference from Example 1 is that step S2, "hydrogen-induced explosion pretreatment," is omitted from the process flow. Specifically, after completing step S1 (feeding and spraying), no instantaneous high-current treatment is performed; instead, the ultrasonic and electrolytic power supplies are directly activated to proceed to step S3 (dynamic machine-acoustic-electric synergistic cleaning). The remaining steps and equipment configuration remain consistent with Example 1, yielding the finished diamond micron powder. Process Comparison Example 2 The difference from Example 1 is that the "flexible wear-resistant scraper ring 9" is not installed in the inner hole of the ultrasonic transducer 2. The specific operation is as follows: In step S3, the annular transducer only performs Z-axis scanning motion and ultrasonic radiation, and does not have the function of mechanically scraping the central cathode rod 5. The remaining steps and equipment configuration are consistent with Example 1, and the diamond micro powder product is obtained.

[0060] Process Comparison Example 3 The difference from Example 1 is that the power supply parameters in step S3 are set to constant direct current (DC) power. Specifically, the positive oxidation voltage is maintained throughout the cleaning process, and a low-voltage, short-cycle reverse desorption / repulsion period is not set. The remaining steps and equipment configuration are consistent with Example 1, resulting in the finished diamond micropowder product. Process Comparison Example 4 The difference from Example 1 is that step S4, "online flotation," is omitted from the process flow. Specifically, the air inlet valve of the bubble generator 15 in the external circulation loop is closed, and the overflow tank 16 at the top of the cleaning vessel is sealed. After cleaning in step S3, the waste liquid is discharged by extracting the supernatant, relying solely on gravity settling. The remaining steps and equipment configuration remain consistent with Example 1, yielding the finished diamond micron powder. Comparative Example 5: The difference from Example 1 is that step S3-B, "in-situ surface grafting modification," is omitted from the process flow. Specifically, after the impurities are cleaned to the required standard in step S3, the current density is not increased to the high oxygen evolution zone, nor is the ultrasonic wave switched to high frequency mode. Instead, the process directly proceeds to steps S4 and S5 for sedimentation and discharge. The remaining steps and equipment configuration are consistent with those in Example 1, resulting in the finished diamond micron powder.

[0061] Test example: Nickel-manganese catalyst synthetic diamond micron powder from the same batch synthesized under high temperature and high pressure (HPHT) with a particle size of 10-20 μm was selected. Initial state of raw materials: initial metal coating (before acid washing): approximately 8.5% (wt); surface condition: under a microscope, obvious black graphite spots and a thick amorphous carbon coating layer were visible; surface wettability: strongly hydrophobic (water contact angle > 80°); basic experimental environment: electrolyte: 15% sulfuric acid + 5% hydrochloric acid aqueous solution; single processing capacity: 50 kg. Under the above-mentioned basic conditions, diamonds were cleaned using the processes described in Examples 1-3 and Comparative Examples 1-5, and the following data were obtained: Total cleaning time (h): The process time required from the start of feeding to the point where the sample was visually free of black spots and met the discharge standard was recorded; Ash content of finished product (ppm): The cleaned and dried sample was calcined in a muffle furnace at 1000℃ for 1 hour, and the weight percentage of residue was measured (reflecting the total impurity content); Magnetic residue (%): Measured using a high-sensitivity magnetic susceptibility meter (reflecting the degree of removal of metal catalysts such as Ni / Mn / Co); Current efficiency retention rate (%): After running 5 batches continuously, the ratio of the average current density of the fifth batch to the initial value of the first batch was monitored (reflecting the stability of the electrode system); Water contact angle (°): Samples were prepared using the pressing method, and measured using an optical contact angle meter (reflecting the surface hydrophilicity and modification effect).

[0062] The test results for the above test items are shown in the table below. The table below shows the test results for Examples 1-3 and Comparative Examples 1-4; Examples 1, 2, and 3 all achieved excellent cleaning results (ash content ≤25ppm, magnetic matter ≤0.003%) and good hydrophilicity (contact angle ≤28°); demonstrating the effectiveness of the process parameters (scanning speed, current density 0.3-0.8A / cm²) defined in the technical solution. 2 The process (frequency 80-120kHz, temperature 40-60℃) has good process effect. Although Example 2 takes a little longer (4.2h), it can still achieve high purity standard, indicating that the lower limit of the process is reliable. Example 3 has extremely high efficiency (3.2h) and the strongest modification effect (18°), indicating that within the equipment's tolerance range, improving the parameters can further optimize the performance. The purification time for Comparative Example 1 was extended to 6.0 hours, and the ash content (280 ppm) and magnetic content (0.050%) of the finished product were significantly higher than those in Example 1. The dense carbon film and metal passivation layer on the diamond surface hindered acid penetration. Without the physical expansion and shell breaking of hydrogen in step S2, it was difficult to destroy the coating layer quickly using only ultrasound, resulting in the inability to remove deep impurities. This demonstrates that "hydrogen-induced explosion pretreatment" is a prerequisite for achieving efficient deep purification. In Comparative Example 2, the current efficiency retention rate dropped to 45%, resulting in magnetic residue as high as 0.080% (product failure). Without a mechanical scraper, the cathode surface was rapidly covered by reduced nickel / cobalt metal (scaling), leading to increased system resistance, a sharp decrease in effective current density, and loss of electrolytic dissolution capacity. Example 1, by using a mechanical scraper to continuously update the electrode surface, maintained highly efficient electrolysis throughout the process, demonstrating that the "self-cleaning structure" is a guarantee for the long-term stable operation of the process. The magnetic residue in Comparative Example 3 (0.015%) was 7.5 times that in Example 1; although constant direct current can dissolve metal, it cannot prevent metal cations from being re-adsorbed onto the diamond surface by electrostatic attraction. Example 1 used the instantaneous repulsive force generated by the pulsed reverse voltage to "push away" trace ions, proving that the "asymmetric pulse mode" is the key to reducing trace metal residues. Comparative Example 4 had a finished product with an ash content as high as 320 ppm and a water contact angle as high as 85° (surface contamination). Comparative Example 4 lacked flotation slag removal, causing the hydrophobic graphite and carbon slag that had been stripped off to re-adhere to the diamond surface during the settling stage (secondary contamination). Example 1 utilized bubble flotation to achieve "washing and slag removal simultaneously," demonstrating that "online flotation" is a necessary means to reduce ash content and prevent secondary contamination. Although Comparative Example 5 met the purity standard (ash content 18 ppm), the product was hydrophobic (contact angle 78°); while the contact angle of Example 1 decreased to 22°. Comparative Example 5 lacked step S3-B, and the diamond surface still retained hydrogen terminals or some hydrophobic groups, resulting in poor dispersibility in water. Example 1, through high oxygen evolution zone current combined with high-frequency ultrasound, in-situ grafted hydrophilic groups. This demonstrates that the "in-situ surface modification" step can significantly improve product dispersibility and increase added value.

[0063] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A cleaning device for the production of synthetic diamonds, comprising a cleaning tank body (1) and an ultrasonic transducer (2) disposed therein; characterized in that: The main body (1) of the cleaning vessel is a vertical acid-resistant container, and its structure includes an upper straight cylindrical section (3) and a lower gravity settling inverted cone (4). The electrochemical assembly includes a central cathode rod (5) suspended vertically along the central axis of the main body (1) of the cleaning vessel, and a circumferential anode ring (6) attached to the inner wall of the straight section (3), which together form a radial electrolysis field; The jet suspension assembly includes a jet ring pipe (7) located at the bottom of the interior of the cleaning vessel body (1) and a circulation loop (8) connecting the assembly to the liquid inlet at the top of the cleaning vessel body (1), which is used to construct a jet circulation flow field that causes diamond particles to rise along the center. The sweeping unit includes an annular ultrasonic transducer (2) coaxially sleeved around the central cathode rod (5) and located inside the circumferential anode ring (6), and a drive mechanism for driving it to reciprocate along the Z-axis in the slurry. Bottom discharge assembly; located at the bottom of the gravity settling inverted cone (4), used to discharge the cleaned artificial diamonds.

2. The cleaning equipment for synthetic diamond production according to claim 1, characterized in that: The ultrasonic transducer (2) has a scraper ring (9) on the inner side of its housing. The inner diameter of the scraper ring (9) is designed to form an interference fit with the outer diameter of the central cathode rod (5); When the ultrasonic transducer (2) moves along the Z-axis, the scraper ring (9) mechanically scrapes away the dense metal reduction layer deposited on the surface of the central cathode assembly.

3. The cleaning equipment for synthetic diamond production according to claim 2, characterized in that: The outer wall surface of the ultrasonic transducer (2) facing the circumferential anode ring (6) is an outwardly convex arc surface (10), which constitutes an acoustic diverging lens to expand the sound wave radiation angle to cover the particle layer falling along the wall. The inner wall of the ultrasonic transducer (2) facing the central cathode rod (5) is a vertical cylindrical surface (11), forming a non-focused acoustic interface for generating plane waves. The piezoelectric ceramic array encapsulated inside the ultrasonic transducer (2) is divided into an outer array group (12) and an inner array group (13); the number of the outer array group (12) is greater than the number of the inner array group (13), and the ratio of the two is selected from the range of 2:1 to 4:

1.

4. The cleaning equipment for synthetic diamond production according to claim 3, characterized in that: The jetting ring pipe (7) has several jet nozzles (14) evenly distributed along the circumference. The axis of the nozzle (14) points to the central axis of the container and is tilted upward relative to the horizontal plane, with the tilt angle ranging from 30° to 60°.

5. The cleaning equipment for synthetic diamond production according to claim 4, characterized in that: The circulation loop (8) includes a bubble generator (15) connected in series in the loop; the bubble generator (15) draws in gas by utilizing the pressure drop when the fluid passes through the throat and generates micro-nano bubbles by utilizing hydraulic shearing. The top of the cleaning vessel body (1) is provided with an overflow trough (16), which is connected to the waste liquid collection pipeline.

6. The cleaning equipment for synthetic diamond production according to claim 5, characterized in that: The driving mechanism includes a movable frame (17), which is slidably connected to the cleaning vessel body (1); a hydraulic cylinder (18) is fixedly connected to the cleaning vessel body (1), and one end of the movable rod of the hydraulic cylinder (18) is fixedly connected to the movable frame (17); a ring frame (19) is provided at the lower part of the movable frame (17); the ultrasonic transducer (2) is rotatably connected to the ring frame (19); and an inclined drive plate (20) is provided on the inner side of the ultrasonic transducer (2).

7. A cleaning and impurity removal process for the production of synthetic diamonds, applicable to any of the cleaning equipment used in the production of synthetic diamonds as described in claims 1-6, characterized in that: Includes the following steps: S1 Feeding and Spraying: Inject the medium, start the external circulation, and use the rising flow generated by the spray ring pipe (7) to establish the "center rise - wall fall" circulation flow of diamond particles; S2 hydrogen-induced explosion pretreatment: Before turning on the ultrasonic waves, a high instantaneous current density or reverse voltage is applied to the electrode system to generate hydrogen gas in the micropores on the cathode and the surface of the diamond particles. The expansion pressure of hydrogen gas evolution is used to destroy the dense carbon film covering the diamond. S3 Dynamic Machine-Acoustic-Electrical Synergistic Cleaning: Turn on the ultrasonic and electrolytic power supply, control the ring transducer to perform Z-axis scanning, and simultaneously use mechanical scraper and ultrasonic field to perform the operation; S4 Sedimentation and Discharge: Stop the circulation and functional field, and wait for the particles to completely settle into the inverted cone under gravity before opening the bottom discharge component to discharge the finished product.

8. The cleaning and impurity removal process for producing synthetic diamonds according to claim 7, characterized in that: In step S3, the ultrasonic transducer (2) is controlled to move upward at a speed greater than 50 mm / s; the ultrasonic transducer (2) is controlled to move downward at a speed less than 10 mm / s.

9. The cleaning and impurity removal process for producing synthetic diamonds according to claim 8, characterized in that: In step S3, an asymmetric pulsed current is applied, which includes a high-voltage, long-cycle oxidation-dissolution period and a low-voltage, short-cycle desorption-repulsion period.

10. The cleaning and impurity removal process for producing synthetic diamonds according to claim 9, characterized in that: Between steps S3 and S4, there is also a step S3-B: after the impurities are removed, the electrolyte in the main body of the cleaning vessel (1) remains unchanged, and the current density of the DC power supply is increased to 0.3 A / cm². 2 Up to 0.8A / cm 2 The high oxygen evolution range; switch the annular ultrasonic transducer (2) to high frequency mode, and set the frequency to 80kHz to 120kHz; control the slurry temperature in the main body (1) of the cleaning vessel to be between 40℃ and 60℃.

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