Bipolar pulsing device, preparation apparatus and preparation method of chloroauric acid

Abstract

This invention relates to the field of fluid pulse technology, disclosing a bidirectional pulse device, a preparation apparatus for chloroauric acid, and a preparation method. The bidirectional pulse device is used to form a bidirectional pulsed laminar flow; the chloroauric acid preparation apparatus includes the bidirectional pulse device; and the preparation method for chloroauric acid is implemented based on the aforementioned preparation apparatus. The preparation method for chloroauric acid includes multiple cyclic steps. The cyclic steps include a forward electrolysis step and a reverse perturbation step, the reverse perturbation step including a flushing sub-step and a backflow sub-step. The bidirectional pulse device, preparation apparatus, and method of this invention can effectively suppress anode passivation when using an electrolyte system with high chloride ion concentration and low pH for the electrolytic preparation of chloroauric acid, thereby achieving higher chloroauric acid yield and current efficiency even when using a gold anode with lower purity.

Description

Technical Field

[0001] This invention relates to the field of fluid pulse technology, and in particular to a bidirectional pulse device, a preparation apparatus for chloroauric acid, and a preparation method thereof. Background Technology

[0002] Chloroauric acid (HAuCl4) is a precursor for electroplating, nanomaterial synthesis, and catalyst preparation. Its industrial production has long relied on chemical methods, such as the aqua regia process and the chlorine-hydrochloric acid process. While these traditional methods are technically mature, they generally suffer from inherent drawbacks such as complex processes, the use of highly corrosive or toxic raw materials (nitric acid, chlorine), the generation of large amounts of harmful waste gases such as nitrogen oxides, high operational risks, and large fluctuations in product purity.

[0003] The electrochemical method for preparing chloroauric acid uses gold as the anode and directly oxidizes and dissolves chloroauric acid in hydrochloric acid medium via electrolysis. Theoretically, it has the potential to be a clean process with strong controllability and high atom economy.

[0004] However, under optimized electrolysis conditions of high chloride ion concentration and low pH, the [AuCl4] generated at the anode reaction... - Complex ions readily reach supersaturation near the anode surface, forming chloroauric acid microcrystal deposits. This not only physically hinders the continued dissolution of gold and reduces current efficiency, but also causes severe uneven current distribution on the anode surface. Abnormal increases in local current density accelerate passivation in that area, which in turn further exacerbates deposition, creating a vicious cycle that leads to rapid instability of the electrolysis process and a decrease in yield. Summary of the Invention

[0005] Therefore, the purpose of this invention is to overcome the problem of decreased chloroauric acid yield caused by anode passivation during the electrochemical preparation of chloroauric acid, and to provide a bidirectional pulse device, chloroauric acid preparation equipment and preparation method. When using an electrolyte system with high chloride ion concentration and low pH for the electrolytic preparation of chloroauric acid, anode passivation can be effectively suppressed, so that even when using a gold anode with lower purity, a higher chloroauric acid yield and current efficiency can be obtained.

[0006] To address the aforementioned technical problems, in a first aspect, the present invention provides a bidirectional pulse device for forming a bidirectional pulsed laminar flow; the bidirectional pulse device includes:

[0007] A bidirectional pump; the A port of the bidirectional pump is connected to a tailpipe, which is inserted into the fluid; the B port of the bidirectional pump is connected to a piping assembly, which is connected to at least one set of nozzle assemblies, which are placed in the fluid;

[0008] Each nozzle assembly includes multiple nozzles, each nozzle comprising a converging section and a stabilizing section; the total cone angle of the converging section is less than 30°; the larger end of the converging section is connected to the piping assembly, and the smaller end of the converging section is connected to the stabilizing section; the length of the stabilizing section is greater than the length of the converging section; the spray direction of the nozzle of the stabilizing section forms an angle of -60° to -30° with the normal vector of the target area.

[0009] Secondly, the present invention provides an apparatus for preparing chloroauric acid, comprising:

[0010] An electrolytic cell, wherein a first mounting buckle is provided on the cell wall furthest from the cathode in the anode chamber of the electrolytic cell;

[0011] The aforementioned bidirectional pulse device, wherein: a first buckle is provided on the tail tube, the first buckle is connected to the first mounting buckle, and the end of the tail tube extends into the electrolyte; it includes multiple sets of nozzle assemblies; at least some of the nozzle assemblies are equally spaced on the side of the anode facing the cathode; the vertical distance between the nozzle of the nozzle assembly and the anode surface is 2mm to 3mm, and the spray direction of the nozzle orifice forms an angle of -60° to -30° with the normal vector of the anode.

[0012] Thirdly, the present invention provides a method for preparing chloroauric acid, which is based on the above-mentioned chloroauric acid preparation equipment; the preparation method includes performing cyclic steps multiple times until a predetermined electrolysis endpoint is reached;

[0013] The cyclic steps include:

[0014] Forward electrolysis step: Turn off the bidirectional pump, use gold as the anode, graphite as the cathode, and a saturated calomel electrode as the reference electrode, control the potential of the anode relative to the reference electrode to +1.25V, perform electrolytic oxidation of gold to prepare chloroauric acid, and continue for the first duration;

[0015] Reverse perturbation step: Start the bidirectional pump and control the potential of the anode relative to the reference electrode to -0.3V; the reverse perturbation step includes the following steps performed sequentially:

[0016] Flushing sub-step: Control the bidirectional pump to rotate in the first direction, use the tailpipe to draw electrolyte, and spray it onto the anode surface through the nozzle; during the flushing sub-step, the first total flow rate of the pipeline assembly is the first target total flow rate, and lasts for a second duration;

[0017] Back-suction step: Control the bidirectional pump to rotate in a second direction opposite to the first direction, so that the nozzle produces a suction effect, forming a flow field pointing towards the nozzle near the anode surface, which is used to guide the gold species that were stripped or suspended near the anode surface in the flushing step away, so as to prevent them from being adsorbed on the anode surface again; in the back-suction step, the second total flow rate of the tailpipe is the second target total flow rate, and it lasts for a third duration.

[0018] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0019] The bidirectional pulse device described in this invention, by combining a bidirectional pump with a nozzle having a tapering section and a stabilizing section, can not only create laminar flow to flush the target area (e.g., the electrode surface) and clean the deposits on the electrode surface, but also create a suction flow field near the electrode surface pointing towards the nozzle, guiding the flushed gold particles away from the electrode surface to prevent them from re-adsorbing onto the electrode surface. Therefore, when preparing chloroauric acid using an electrolytic device with a bidirectional pulse device, anolyte passivation can be suppressed, thereby achieving higher yields and current efficiency.

[0020] Furthermore, the total cone angle of the nozzle's tapering section is less than 30°, ensuring a smooth acceleration of the ejected fluid and preventing vortices caused by excessive angle. The longer steady-flow section eliminates velocity fluctuations in the accelerated fluid, ensuring a uniform and stable jet flow field at the nozzle. The inclined jet design provides shear force parallel to the electrode surface to effectively remove deposits and prevent anodic passivation, while also avoiding pitting or damage to the electrode surface caused by vertical impacts, which could affect the forward electrolysis reaction.

[0021] The method for preparing chloroauric acid described in this invention, by cyclically executing forward electrolysis and reverse perturbation steps, can promptly remove deposits on the anode surface. This effectively suppresses anode passivation when using an electrolyte system with high chloride ion concentration and low pH for the electrolytic preparation of chloroauric acid, thereby achieving higher chloroauric acid yield and current efficiency even when using a gold anode with lower purity.

[0022] Specifically, the reverse disturbance step also includes a flushing sub-step and a back-suction sub-step. The flushing sub-step can create a laminar flow to flush away the deposits on the anode surface; the back-suction sub-step can create a flow field near the anode surface pointing towards the nozzle to guide the flushed gold species away from the anode surface and prevent them from being re-adsorbed onto the anode surface.

[0023] Furthermore, the electrolyte in the anode chamber is Cl. - A 1.0 mol / L hydrochloric acid solution with a pH of 1.0 contains 8.0 mmol of H₂O₂; the electrolyte in the cathode chamber is Cl₂. -A 1.0 mol / L sodium chloride aqueous solution is used to ensure that chloride ions can continuously migrate through the anion exchange membrane under anodic reaction conditions of high chloride ion concentration and low pH, thus maintaining the stability of the electrolysis process. Attached Figure Description

[0024] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0025] Figure 1 This is a schematic diagram of a bidirectional pulse device in an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of a nozzle structure in an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of a nozzle assembly in an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of a mounting ring structure in an embodiment of the present invention.

[0029] Figure 5 This is a schematic diagram of a cleaning component in an embodiment of the present invention.

[0030] Figure 6 This is a schematic diagram of another structure of the nozzle assembly in an embodiment of the present invention.

[0031] Figure 7 This is a schematic diagram of the electrolysis equipment in an embodiment of the present invention.

[0032] Explanation of reference numerals in the accompanying drawings: 1. Bidirectional pump; 2. Tailpipe; 3. Piping assembly; 31. First piping; 32. Second piping; 4. Nozzle assembly; 41. Nozzle; 411. Flow stabilizing section; 412. Gradient section; 413. Connecting section; 42. Mounting frame; 43. Mounting ring; 421. Normal vector of the mounting frame; 431. Central axis of the mounting ring; 5. Electrolytic cell; 51. Anode; 52. Reference electrode; 53. Cathode; 54. Anion exchange membrane; 61. Three-way valve; 62. Cleaning piping; 63. Cleaning source; 64. Cleaning pump; 7. Telescopic assembly; 71. Mounting bracket; 72. First mounting pipe; 73. Second mounting pipe; 731. Adjustment through hole; 74. Limiting rod. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0034] In the industrial chloroauric acid electrolyzer 5, when operating under high chloride ion concentration and low pH electrolysis conditions, [AuCl4] near the surface of the anode 51... - The concentration of the complex ion rapidly increases, reaching saturation, leading to the formation of chloroauric acid microcrystals in localized areas of the anode 51 surface. As deposits accumulate on the anode 51 surface, the current density in the corresponding area increases abnormally, accelerating the formation of the passivation layer. This passivation layer hinders the gold dissolution process, for example, increasing electrolytic current fluctuations and decreasing yield. Therefore, this invention provides a bidirectional pulse device, a chloroauric acid preparation apparatus, and a preparation method.

[0035] The bidirectional pulse device of the present invention is used to generate bidirectional fluid pulses. Specifically, by controlling the flow direction and intensity of the fluid, periodic flushing and suction effects are formed in the target area to achieve the transfer of substances in the fluid or to achieve surface cleaning of the target area.

[0036] Example 1: This example discloses a bidirectional pulse device for generating bidirectional fluid pulses.

[0037] The bidirectional pulse device of this embodiment includes a bidirectional pump 1, a tailpipe 2, a piping assembly 3, and a nozzle assembly 4, for generating bidirectional fluid pulses. Further, the bidirectional pulse device of this embodiment also includes a cleaning assembly for cleaning the piping 62, piping assembly 3, and nozzle assembly 4. Even further, the bidirectional pulse device of this embodiment also includes at least one set of telescopic components 7 for adjusting the longitudinal coordinate of the nozzle assembly 4, i.e., for adjusting the height of the nozzle assembly 4.

[0038] refer to Figure 1 In this embodiment, the A port of the bidirectional pump 1 is connected to the tailpipe 2, which is inserted into the fluid, thereby enabling the bidirectional pump 1 to draw fluid from or deliver fluid to the fluid. The B port of the bidirectional pump 1 is connected to the piping assembly 3, which is connected to at least one set of nozzle assemblies 4, which are placed in the fluid.

[0039] In application, by controlling the operating direction of the bidirectional pump 1, fluid can be drawn from the tailpipe 2 and sprayed out through the nozzle assembly 4, or drawn in through the nozzle assembly 4 and discharged through the tailpipe 2. For example, the bidirectional pump 1 can be a centrifugal pump or gear pump driven by a reversible motor, and the direction of fluid delivery can be switched by changing the rotation direction of the motor.

[0040] In practical applications, the tailpipe 2, pipeline assembly 3, and nozzle assembly 4 in this embodiment are made of insulating materials. Furthermore, the insulating materials are polytetrafluoroethylene, polypropylene, polyvinyl chloride, or fluorinated ethylene propylene copolymer.

[0041] In actual implementation, the tailpipe 2 is provided with a first buckle for connecting with the first connecting buckle of the equipment containing the fluid, so as to prevent the end of the tailpipe 2 from being separated from the fluid due to the fluid force or other external forces, or to prevent the tailpipe 2 from moving in the fluid due to the fluid force or other external forces, thereby generating unnecessary flow field disturbances.

[0042] Furthermore, both the first snap-fit ​​and the first connecting snap-fit ​​are made of insulating material. Furthermore, the first snap-fit ​​and the first connecting snap-fit ​​can be connected by a threaded structure or by a plug-in structure.

[0043] The piping assembly 3 of the present invention includes two structures.

[0044] The first type of pipe assembly 3 includes a first pipe 31 and a second pipe 32. Furthermore, the pipe assembly 3 may also include a channel plate.

[0045] When applying, refer to Figure 1 and Figure 5 One end of the first pipe 31 is connected to port B of the bidirectional pump 1, and the other end of the first pipe 31 is connected to at least one set of second pipes 32, each set of second pipes 32 being connected to the nozzle assembly 4. Further, refer to... Figure 1 and Figure 5 The second conduit 32 includes multiple branch pipes that connect to the nozzle assembly 4. The inner diameter of each branch pipe is the same as the maximum inner diameter of the nozzle assembly 4. Furthermore, the branch pipe can be a flexible hose.

[0046] In practical applications, the first pipe 31 is equipped with a second clip, which can be used to connect with the second connecting clip of the equipment containing fluid. This prevents the pipe assembly 3 from detaching from the fluid due to fluid force or other external forces, or from exerting a pulling or pushing force on the nozzle assembly 4, causing the nozzle assembly 4 to shift its position; or prevents the pipe assembly 3 from moving in the fluid due to fluid force or other external forces, thereby causing unnecessary flow field disturbance. Both the second clip and the second connecting clip are made of insulating material. Furthermore, the second clip and the second connecting clip can be connected by a threaded structure or by a plug-in structure.

[0047] In actual implementation, the trough plate is used to accommodate at least a portion of the first conduit 31. The trough plate has at least one slot for at least one through which the second conduit 32 passes. The trough plate can be installed above a device containing fluid.

[0048] The second type of piping assembly 3 includes: a first piping 31 and a second piping 32.

[0049] In application, one end of the first pipe 31 is connected to port B of the bidirectional pump 1, and the other end of the first pipe 31 is connected to at least one second pipe 32, and each second pipe 32 is connected to the nozzle assembly 4.

[0050] In practical applications, refer to Figure 6 The second conduit 32 can be a rigid conduit, and multiple mounting holes are provided on the second conduit 32 along the Z-axis direction for mounting the nozzle assembly 4. Furthermore, the angle between the axis of symmetry of the mounting hole and the XOY plane is -60° to -30°.

[0051] The telescopic component 7 in this embodiment includes: a mounting bracket 71 and a telescopic structure.

[0052] In application, the telescopic structure is mounted on the mounting bracket 71. When the piping assembly 3 is the first type of piping assembly 3, the mounting bracket 71 can be installed at the bottom of the electrolytic cell 5, as shown in the reference. Figure 1 and Figure 3 When the piping assembly 3 is of the second structure, the mounting bracket 71 can be installed above the electrolytic cell 5, or on the wall of the electrolytic cell 5, as shown in the reference. Figure 6 .

[0053] Furthermore, the mounting bracket 71 can be slidably connected to the device containing the fluid. For example, the mounting bracket 71 can be moved along the X-axis and / or Y-axis to adjust the X-axis and / or Y-axis coordinates of the mounting bracket 71.

[0054] In practical applications, the telescopic component 7 is made of insulating material. Furthermore, the insulating material may also include glass fiber reinforced nylon, polyetheretherketone, or polysulfone.

[0055] Furthermore, the telescopic structure includes a limiting rod 74 and a first mounting tube 72 and a second mounting tube 73 that are telescopically slidingly fitted.

[0056] Specifically, one end of the first mounting tube 72 is mounted on the mounting bracket 71, and the other end of the first mounting tube 72 has a positioning through hole; one end of the second mounting tube 73 is connected to the nozzle assembly 4, and the other end of the second mounting tube 73 has a plurality of equally spaced adjustment through holes 731 along the extension direction of the mounting tube. By replacing the adjustment through holes 731 that are connected to the positioning through hole, and by replacing the adjustment through holes 731 that are connected to and aligned with the positioning through hole, the contraction length or extension length of the telescopic structure can be adjusted, that is, the Z-axis coordinate of the nozzle assembly 4 can be adjusted.

[0057] In actual implementation, the limiting rod 74 passes through the positioning through hole and the adjusting through hole 731 to fix the length of the current telescopic structure. Furthermore, fasteners, such as nuts, are also included on both sides of the limiting rod 74 to prevent the limiting rod 74 from slipping out of the positioning through hole and / or adjusting through hole 731.

[0058] When the pipeline assembly 3 is the pipeline assembly 3 of the first structure, the nozzle assembly 4 of the present invention includes: a plurality of nozzles 41, a mounting frame 42 and a ring array.

[0059] When applying, the mounting surface of mounting frame 42 should be parallel to the target area. (See reference) Figure 3 and Figure 4 The mounting frame 42 is provided with a ring array, which includes a plurality of mounting rings 43. The first side of the mounting ring 43 is connected to the branch pipe of the pipeline assembly 3, and the second side of the mounting ring 43 opposite to the first side is connected to the nozzle 41.

[0060] In practical applications, multiple mounting rings 43 are evenly spaced along the Z-axis, meaning that multiple mounting rings 43 are arranged in a row along the Z-axis. Furthermore, a first gasket is provided on the first side of each mounting ring 43, and the first side of the mounting ring 43 is threadedly connected to the branch pipe of the pipeline assembly 3; a second gasket is provided on the second side of each mounting ring 43, and the second side of the mounting ring 43 is threadedly connected to the nozzle 41.

[0061] In actual implementation, refer to Figure 4 The central axis 431 of the mounting ring forms an angle of -60° to -30° with the normal vector 421 of the mounting frame, such that the spray direction of the nozzle 41 forms an angle of -60° to -30° with the normal vector of the target area. Further, the spray direction of the nozzle 41 forms an angle of -60° to -45° with the normal vector of the target area. Preferably, the spray direction of the nozzle 41 forms an angle of -45° with the normal vector of the target area.

[0062] When the piping assembly 3 is of the second structure, the nozzle assembly 4 of the present invention includes a plurality of nozzles 41, the nozzles 41 being connected to mounting holes. In application, the spray direction of the nozzles 41 forms an angle of -60° to -30° with the normal vector of the target area. Further, the spray direction of the nozzles 41 forms an angle of -60° to -45° with the normal vector of the target area. Preferably, the spray direction of the nozzles 41 forms an angle of -45° with the normal vector of the target area.

[0063] The nozzle 41 in this embodiment includes a connecting section 413, a tapering section 412, and a flow stabilizing section 411 connected in sequence. (Refer to...) Figure 2 .

[0064] In application, when the pipe assembly 3 is a pipe assembly 3 of the first structure, one end of the connecting section 413 is connected to the branch pipe of the pipe assembly 3, and the inner diameter of the connecting section 413 is equal to the inner diameter of the branch pipe; when the pipe assembly 3 is a pipe assembly 3 of the second structure, one end of the connecting section 413 is connected to the second pipe 32 of the pipe assembly 3, and the inner diameter of the connecting section 413 is equal to the inner diameter of the second pipe 32.

[0065] The inner diameter of the connecting section 413 is constant throughout. The large end of the tapered section 412 connects to the connecting section 413, and the inner diameter of the large end of the tapered section 412 is the same as that of the connecting section 413. The small end of the tapered section 412 connects to the flow stabilizing section 411, and the inner diameter of the small end of the tapered section 412 is the same as that of the flow stabilizing section 411, and the inner diameter of the flow stabilizing section 411 is constant throughout. Furthermore, the tapered section 412 has a tapered structure, and the total cone angle of the tapered section 412 is less than 30°. Preferably, in order to reduce the resistance of the fluid contraction process and improve the flushing efficiency, the total cone angle of the tapered section 412 is 15° to 20°, which also ensures that the fluid has completed a smooth transition before entering the flow stabilizing section 411.

[0066] In practical applications, the length of the stabilizing section 411 is greater than the length of the tapering section 412 to ensure that the jet forms a uniform laminar flow when it leaves the nozzle 41, thereby improving the uniformity of the scouring. Specifically, the length of the stabilizing section 411 is 10 mm to 30 mm; the length of the tapering section 412 is 5 mm to 15 mm. Preferably, the length of the stabilizing section 411 is 15 mm; the length of the tapering section 412 is 5 mm to 7 mm, which ensures smooth fluid acceleration and the formation of a stable laminar flow, while also improving the compactness of the structure to ensure the feasibility of the manufacturing process.

[0067] The cleaning components in this embodiment include: a three-way valve 61, a cleaning pipeline 62, a cleaning source 63, and a cleaning pump 64. (See reference...) Figure 5 .

[0068] In application, the electrolyte in the chloroauric acid preparation system is highly acidic and corrosive. Prolonged operation may cause blockage or reduced efficiency of the pipeline assembly 3 and nozzle 41 due to the accumulation of impurities. The cleaning component of this embodiment can clean the pipeline system by periodically or as needed by introducing the cleaning source 63 without disassembling the device.

[0069] Specifically, the first end of the three-way valve 61 is connected to port B of the bidirectional pump 1, the second end of the three-way valve 61 is connected to the first pipe 31 of the piping assembly 3, the third end of the three-way valve 61 is connected to one end of the cleaning pipe 62, and the other end of the cleaning pipe 62 is connected to the cleaning source 63. A cleaning pump 64 is installed on the cleaning pipe 62. The cleaning pump 64 can be a unidirectional pump, and the cleaning source 63 can be a 5wt% dilute hydrochloric acid solution or deionized water stored in a tank.

[0070] In practical applications, when cleaning of the piping assembly 3 and nozzle 41 is not required, the bidirectional pump 1 is turned off; and the third end of the three-way valve 61 is closed, while the first and second ends of the three-way valve 61 are opened. When cleaning of the piping assembly 3 and nozzle 41 is required, the first end of the three-way valve 61 is closed, while the third and second ends of the three-way valve 61 are opened; and the cleaning pump 64 is started to pump the cleaning source 63 into the cleaning piping 62, which then enters the piping assembly 3 and nozzle 41 through the three-way valve 61 to flush the piping assembly 3 and nozzle 41.

[0071] In practical applications, when the cleaning source 63 is not deionized water, after rinsing the pipeline assembly 3 and nozzle 41 with the cleaning source 63, the cleaning source 63 in the cleaning assembly needs to be replaced with deionized water. The deionized water is then pumped into the cleaning pipeline 62 and enters the pipeline assembly 3 and nozzle 41 through the three-way valve 61 to remove residue from the pipeline assembly 3 and nozzle 41.

[0072] Example 2: This example discloses an apparatus for preparing chloroauric acid.

[0073] The chloroauric acid preparation equipment in this embodiment includes an electrolysis device and a bidirectional pulse device as described in Example 1.

[0074] The electrolysis apparatus of this embodiment includes an electrolytic cell 5 and a potentiostat.

[0075] In application, the electrolytic cell 5 includes anion exchange membrane 54, which divides the electrolytic cell 5 into a cathode chamber and an anode chamber. The cathode chamber contains a cathode 53, and the anode chamber contains an anode 51 and a reference electrode 52. Figure 7 .

[0076] In practical applications, the anode 51, cathode 53, and reference electrode 52 are connected to the corresponding terminals of the potentiostat. Specifically, the anode 51 is connected to the WE terminal of the potentiostat, the cathode 53 is connected to the CE terminal of the potentiostat, and the reference electrode 52 is connected to the REF terminal of the potentiostat.

[0077] In actual implementation, a first mounting buckle is provided on the tank wall furthest from the cathode 53 in the anode chamber of the electrolytic cell 5. Furthermore, a first mounting buckle is also provided on the tank wall on the side furthest from the cathode 53 in the anode chamber.

[0078] The bidirectional pulse device in this embodiment includes a first latch, which is disposed on the tail tube 2 and connected to the first mounting buckle. This allows the end of the tail tube 2 to extend into the electrolyte and be fixed in the anode chamber away from the cathode 53, thereby preventing the extraction or discharge operation of the tail tube 2 from interfering with the flow field between the cathode 53 and the anode 51. Furthermore, the horizontal height of the first mounting buckle is lower than the preset electrolyte level in the electrolytic cell 5 to ensure that the end of the tail tube 2 is always immersed in the electrolyte.

[0079] In application, the bidirectional pulse device comprises multiple nozzle assemblies 4, with at least some nozzle assemblies 4 being equally spaced on the side of the anode 51 facing the cathode 53. The vertical distance between the nozzle 41 of the nozzle assembly 4 and the surface of the anode 51 is 2mm to 3mm, and the spray direction of the nozzle 41 forms an angle of -60° to -30° with the normal vector of the anode 51.

[0080] In practical applications, multiple nozzle assemblies 4 are equally spaced on the side of the anode 51 facing away from the cathode 53, as shown in the reference. Figure 1 Alternatively, multiple nozzle assemblies 4 can be equally spaced on the side of the anode 51 facing the cathode 53, as shown in the reference. Figure 7 b. For example, at least three sets of nozzle assemblies 4 are equally spaced on the side of the anode 51 facing the cathode 53. In other embodiments, the multiple sets of nozzle assemblies 4 are divided into two large groups, wherein the first large group of nozzle assemblies 4 is equally spaced on the side of the anode 51 facing the cathode 53; and the second large group of nozzle assemblies 4 is equally spaced on the side of the anode 51 facing away from the cathode 53, see reference. Figure 7 c. It is worth noting that the number of nozzle assemblies 4 in the second group can be less than the number of nozzle assemblies 4 in the first group.

[0081] In actual implementation, the bidirectional pulse device also includes a first flow meter, a second flow meter, a primary filter, and a secondary filter. The first flow meter detects the first total flow rate flowing through the first pipe 31, and the second flow meter detects the second total flow rate flowing through the tailpipe 2. The primary filter is installed inside the first pipe 31, and the secondary filter is installed inside the tailpipe 2.

[0082] Example 3: This example discloses a method for preparing chloroauric acid.

[0083] The method for preparing chloroauric acid in this embodiment can be implemented based on the chloroauric acid preparation equipment described in Example 2.

[0084] The method for preparing chloroauric acid in this embodiment includes performing cyclic steps multiple times until a predetermined electrolysis endpoint is reached.

[0085] When applied, the cyclic steps include: a forward electrolysis step and a reverse perturbation step.

[0086] In practical applications, the predetermined electrolysis endpoint can be a cumulative dissolved gold mass greater than or equal to 80% of the initial mass of anode 51. That is, the cycle stops when the cumulative dissolved gold mass is greater than or equal to 80% of the initial mass of anode 51.

[0087] Furthermore, the predetermined electrolysis endpoint can also be defined as the average current of the forward electrolysis steps in three consecutive cycles being less than or equal to 50% of the average current of the forward electrolysis steps in the first cycle. That is, the cycle is stopped when the average current of the forward electrolysis steps in three consecutive cycles is less than or equal to 50% of the average current of the forward electrolysis steps in the first cycle. Specifically, during the duration of the forward electrolysis step, the current value flowing through the anode 51 is acquired in real time at a frequency of 1Hz using a potentiostat, and the average current during the forward electrolysis step is calculated.

[0088] The forward electrolysis step of this embodiment includes: turning off the bidirectional pump 1, using gold as the anode 51, graphite as the cathode 53, and a saturated calomel electrode as the reference electrode 52, and keeping the potential of the anode 51 relative to the reference electrode 52 constant at +1.25V, performing electrolytic oxidation of gold to prepare chloroauric acid, and continuing for a first duration.

[0089] When applied, the first duration is 25 to 35 minutes.

[0090] In practical applications, as electrolysis proceeds, the concentration of chloroauric acid near the surface of anode 51 increases, increasing the risk of passivation. Therefore, as the number of cycles increases, the first duration can be gradually shortened. For example, with each additional cycle, the first duration is reduced by 1 to 3 minutes until it reaches 15 minutes, at which point the first duration no longer changes with the number of cycles.

[0091] In actual implementation, the main electrochemical dissolution reaction occurring in the forward electrolysis step is: Au + 4Cl⁻. - →[AuCl4] - +3e - Near the surface of anode 51, [AuCl4] - The concentration increases rapidly and easily reaches saturation, which in turn induces the precipitation of chloroauric acid microcrystals HAuCl4·xH2O, thereby covering the active sites on the surface of anode 51, resulting in a sharp increase in local current density, and thus triggering passivation of anode 51.

[0092] In Cl - At higher concentrations, at an anode potential of 1.25V (vs. SCE), a chlorine evolution side reaction occurs: 2Cl₂ - →Cl2(g)+2e -The generated chlorine gas will partially dissolve and hydrolyze, forming oxidizing substances such as hypochlorous acid. On the one hand, it may oxidize gold, forming gold black or micron-sized gold particles on or near the surface of anode 51, further clogging the surface or changing its electrochemical properties. On the other hand, it will cause fluctuations in electrolyte composition, generate corrosive gases, and form bubbles that adhere to the surface of anode 51, exacerbating local current unevenness and passivation.

[0093] When there are oxides or impurities on the surface of anode 51, a local oxygen evolution side reaction may occur: 2H2O→O2(g)+4H + +4e - Oxygen bubbles can interfere with mass transfer.

[0094] The reverse disturbance step in this embodiment includes: starting the bidirectional pump 1 and switching the potential of the anode 51 to -0.3V relative to the reference electrode 52, and then sequentially executing the flushing sub-step and the back suction sub-step.

[0095] In application, a potential buffering step is performed before the flushing sub-step. The potential buffering step includes: switching the potential of the anode 51 relative to the reference electrode 52 from +1.25V to 0V, starting the bidirectional pump 1 to rotate in a first direction, and when the first total flow rate of the bidirectional pump 1 is greater than or equal to 90% of the first target total flow rate, switching the potential of the anode 51 relative to the reference electrode 52 from 0V to -0.3V.

[0096] If the potential of anode 51 is switched directly from +1.25V to -0.3V, the 1.55V potential difference will generate a huge instantaneous current, which will impact the electrodes and power supply equipment. In the potential buffering step, the potential of anode 51 is first switched from +1.25V to 0V. The gold in anode 51 is neither oxidized nor significantly reduced, allowing the current to transition smoothly and the flow field to stabilize.

[0097] After the first total flow rate is greater than or equal to 90% of the first target total flow rate, the potential of anode 51 is switched to -0.3V to ensure that the scouring flow field has been fully established. At this time, electrochemical reduction is performed on the surface of anode 51 to remove the passivation film or adsorbents on the surface of anode 51. This allows the reduction products to be carried away in time, which can enhance the synergistic effect of the two passivation removal mechanisms of fluid scouring and electrochemical reduction.

[0098] In practical applications, in order to effectively flush away deposits on the surface of the anode 51 without causing turbulent impact damage to the surface of the anode 51, and to avoid bubble entrainment, the first target total flow rate ensures that the average flow velocity at each nozzle 41 orifice is between 0.10 m / s and 0.40 m / s. Preferably, the first target total flow rate ensures that the average flow velocity at each nozzle 41 orifice is between 0.15 m / s and 0.25 m / s.

[0099] The flushing sub-step of this embodiment includes: controlling the bidirectional pump 1 to rotate in the first direction, using the tail pipe 2 to extract electrolyte, and spraying it onto the surface of the anode 51 in the form of a laminar jet through the nozzle 41.

[0100] In application, during the flushing sub-step, the first total flow rate of the pipeline assembly 3 is the first target total flow rate, and this continues for a second duration. Furthermore, to ensure that the laminar jet can cover the edge and central regions of the anode 51 surface, or even the entire anode 51 surface, uniform flushing is achieved, avoiding the accumulation of local deposits. In this embodiment, the second duration is 90 to 150 seconds. Preferably, the second duration in this embodiment is 100 to 120 seconds.

[0101] In practical applications, the laminar jet generates parallel shear force on the surface of anode 51, mechanically stripping and removing the loose passivation film, chloroauric acid microcrystals, adsorbed bubbles, and impurities formed during the forward electrolysis step. While the anode 51 potential of -0.3V vs. SCE is insufficient to cause significant gold deposition, it may reduce some high-valence gold oxides on the anode 51 surface, such as trivalent gold, converting them into metallic gold or lower-valence, easily soluble species. This loosens the passivation layer structure, making it easier for the fluid to wash away. Specifically, this includes the reaction: Au₂O₃ + 6H₂O + +6e - → 2Au + 3H₂O; [AuCl₄] - +3e - →Au+4Cl - (slow).

[0102] The back-suction step of this embodiment includes: controlling the bidirectional pump 1 to rotate in a second direction opposite to the first direction, so that the nozzle 41 generates a suction effect, forming a flow field pointing towards the nozzle 41 near the surface of the anode 51, which is used to guide the gold species that are stripped or suspended near the surface of the anode 51 in the rinsing step away, so as to prevent them from being adsorbed on the surface of the anode 51 again.

[0103] In application, the gold species shall include at least one of these substances: tetrachloroalloyate ion [AuCl4] - Trichlorohydroxyl alloying acid anion [AuCl3(OH)] - Dichlorodihydroxy acid anion [AuCl2(OH)2] - ; hydrated chloroauric acid molecule HAuCl4·nH2O; hydrated chloroauric acid crystals, such as HAuCl4·2H2O, HAuCl4·3H2O, HAuCl4·4H2O; monochloroalloy anion [AuCl2] -; Oxides of gold, such as gold(III) oxide and its hydrates; Hydroxyoxides of gold, such as AuO(OH); Mixed-phase chlorooxides of gold, such as AuCl X (OH) 3-X ·nH2O, 0 < x < 3; Metallic gold particles, such as gold black, nanoscale gold particles, and micron-scale gold particles.

[0104] In actual application, in the back-suction step, the second total flow rate of the tail pipe 2 is the second target total flow rate. In order to both effectively suction and avoid overly disturbing the overall concentration distribution of the electrolyte, the second target total flow rate is 20% to 40% of the first target total flow rate.

[0105] In addition, the back-suction step lasts for a third duration. Further, in order to form a stable flow field pointing to the nozzle 41 to guide the migration of gold species and avoid local depletion of the electrolyte due to long-term suction, the third duration in this embodiment is 5 seconds to 10 seconds.

[0106] During the actual implementation process, when the nozzle 41 changes from spraying to suction, it can suck away the attachments in the depressions on the surface of the anode 51, further cleaning the surface of the anode 51; at the same time, it can form a weak flow field pointing to the nozzle 41 near the surface of the anode 51 to guide and transport the gold species suspended near the surface of the anode 51 after the flushing step. If the gold species near the surface of the anode 51 are not removed in time, the gold species will randomly attach to the surface of the anode 51 again after the solution perturbation stops. In addition, the potential of the anode 51 remains at -0.3V, which can inhibit the re-oxidation of any gold species brought back to the near-electrode region by the back-suction flow field and may continue to reduce the residual surface oxides on the surface of the anode 51 that have not been completely washed away.

[0107] It is worth noting that the flushing and suction effects in this embodiment suck away a part of the electrolyte near the surface of the anode 51 where gold species have been locally enriched, and at the same time draw fresh or electrolyte with a lower gold species concentration from the main body of the electrolytic cell 5, accelerating the renewal of the electrolyte near the surface of the anode 51 and providing more favorable initial conditions with a steeper concentration gradient for the forward electrolysis step of the next execution of the cyclic step.

[0108] Example 4: In this example, chloroauric acid is prepared according to the preparation method of chloroauric acid recorded in Example 3.

[0109] In this example, 10 groups of experimental groups are set up to prepare chloroauric acid.

[0110] Experimental group 1: The anode 51 is a 99.99% gold plate; the electrolytic device recorded in Example 2 is used, that is, the bidirectional pulse device is not installed, and an electrolysis method including a forward electrolysis step and a reverse electrolysis step is used to prepare chloroauric acid.

[0111] The anion exchange membrane 54 of the electrolytic cell 5 is a FAA-3-PK-130 type membrane with a thickness of 130 μm, a width of 90 mm, and a height of 120 mm. The anion exchange membrane 54 is installed in the middle of the electrolytic cell 5, which is made of plexiglass, via a flange frame to divide the electrolytic cell 5 into a cathode chamber and an anode chamber of equal volume.

[0112] The inner cavities of the cathode chamber and the anode chamber are all 10 cm in length, width, and height. Cathode 53 is placed in the cathode chamber; anode 51 and reference electrode 52 are placed in the anode chamber. The distance between the Luggin capillary port of the reference electrode 52 (saturated calomel electrode) and the surface of the anode 51 is approximately 5 mm, and its installation position is on the side of the anode 51 facing away from the cathode 53. Cathode 53, anode 51, and anion exchange membrane 54 are arranged parallel to each other, with a distance of 4 cm between cathode 53 and anion exchange membrane 54, and a distance of 4 cm between anode 51 and anion exchange membrane 54. Anode 51 is a gold plate with a purity of 99.99%, a thickness of 2 mm, a width of 60 mm, and a height of 60 mm; cathode 53 is a graphite plate with a thickness of 5 mm, a width of 80 mm, and a height of 80 mm.

[0113] The electrolysis method used in this embodiment, which includes forward electrolysis steps and reverse electrolysis steps, involves cyclically executing the forward electrolysis steps and reverse electrolysis steps until a predetermined electrolysis endpoint is reached.

[0114] Forward electrolysis step: Using gold as the anode 51, graphite as the cathode 53, and a saturated calomel electrode as the reference electrode 52, the potential of the anode 51 relative to the reference electrode 52 is constantly controlled at +1.25V to electrolytically oxidize gold to prepare chloroauric acid, and this process is continued for a first duration. The first duration is 28 minutes, and the experimental temperature is room temperature, approximately 25°C.

[0115] Reverse electrolysis step: The potential of the anode 51 relative to the reference electrode 52 is switched from +1.25V to -0.3V; and this is continued for a fourth duration of 118 seconds.

[0116] Electrolyte preparation:

[0117] Take 1600 mL of deionized water in a beaker. In a fume hood, slowly add approximately 166 mL of concentrated hydrochloric acid (36%, density 1.18). At this point, Cl... - The concentration is close to 1.0 mol / L. Monitor with a pH meter, and adjust the pH to 1.0 by adding concentrated hydrochloric acid or NaOH solution. Then replenish the Cl₂ using solid NaCl. - The concentration was increased to 1.0 mol / L to obtain a mixed solution.

[0118] Add 800 mL of the mixture to the cathode chamber as the electrolyte for the cathode chamber.

[0119] Take 800 mL of the mixture into another beaker, add 1.36 mL of 30 wt% hydrogen peroxide solution (containing 8 mmol H2O2), stir well, and then add it to the anode chamber as the electrolyte for the anode chamber.

[0120] Experimental Group 2: The difference between Experimental Group 2 and Experimental Group 1 is the distance between the electrodes and the preparation of the electrolyte.

[0121] Distance between electrodes: The cathode 53, anode 51 and anion exchange membrane 54 are arranged in parallel to each other, and the distance between the cathode 53 and the anion exchange membrane 54 is 5cm, and the distance between the anode 51 and the anion exchange membrane 54 is 5cm.

[0122] Electrolyte preparation: The electrolyte in the anode chamber is 800 mL, Cl... - A 1.0 mol / L hydrochloric acid solution with a pH of 1.0 contains 8.0 mmol H₂O₂; the cathode electrolyte is 800 mL Cl₂. - A 1.0 mol / L sodium chloride aqueous solution ensures that chloride ions can continuously migrate through the anion exchange membrane 54 under the anode reaction conditions of high chloride ion concentration and low pH, thus maintaining the stable progress of the electrolysis process.

[0123] Specifically, the electrolyte for the anolyte chamber is prepared as follows: Measure approximately 800 mL of deionized water into a beaker. Inside a fume hood, use a pipette to add 85.0 mL of concentrated hydrochloric acid (36% by mass, density 1.18 g / mL), and stir. At this point, the solution contains Cl... - The concentration is approximately 1.0 mol / L, and the pH value is approximately 1.0. To avoid introducing Na... + The pH was adjusted to 1.0 using diluted hydrochloric acid solution. Next, 1.36 mL of 30 wt% hydrogen peroxide solution was added and stirred until homogeneous. Finally, the volume was brought to 800 mL with deionized water to obtain the anolyte electrolyte.

[0124] Preparation of the cathode electrolyte: Weigh 46.77 g of sodium chloride (NaCl, analytical grade) into a beaker, add approximately 800 mL of deionized water, and stir until completely dissolved. Dilute to 800 mL with deionized water to obtain Cl... - The cathode electrolyte has a concentration of approximately 1.0 mol / L.

[0125] Experimental Group 3: The difference between Experimental Group 3 and Experimental Group 2 is that the anode 51 is a gold plate with a purity of 99.00%.

[0126] Experimental Group 4: Anode 51 is a gold plate with a purity of 99.00%; chloroauric acid is prepared using the electrolysis equipment described in Example 2 and the electrolysis method described in Example 3.

[0127] In application, the piping assembly 3 is a second-structure piping assembly 3, with three second pipes 32 and three sets of nozzle assemblies 4, which are equally spaced on the side of the anode 51 facing the cathode 53. Each nozzle assembly 4 includes nine nozzles 41, equally distributed along the height of the anode 51, with a spacing of approximately 7.5 mm between the nozzles 41. The vertical distance between the nozzles 41 and the surface of the anode 51 is approximately 2.5 mm, and the spray direction of the nozzles 41 forms an angle of -45° with the normal vector of the anode 51. The total cone angle of the tapered section 412 is 18°, the inner diameter of the large end of the tapered section 412 is 3.0 mm, the inner diameter of the small end of the tapered section 412 is 1.0 mm, and the length of the tapered section 412 is 6.4 mm; the length of the flow stabilizing section 411 is 15 mm.

[0128] In practical applications, during the flushing sub-step: the first target total flow rate is 4.23 mL / s, making the average flow velocity of nozzle 41 approximately 0.20 m / s, and the second duration is 110 seconds.

[0129] In the back suction step: the second target total flow rate is 30% of the first target total flow rate, that is, the second target total flow rate is 1.27 mL / s, so that the average back suction speed of nozzle 41 is 0.06 m / s, and the third duration is 8 seconds.

[0130] Experimental Group 5: The difference between Experimental Group 5 and Experimental Group 4 is that six sets of nozzle assemblies 4 are set up. Among them, three sets of nozzle assemblies 4 are set at equal intervals on the side of the anode 51 facing the cathode 53; the other three sets of nozzle assemblies 4 are set at equal intervals on the side of the anode 51 away from the cathode 53.

[0131] Experimental Group 6: The difference between Experimental Group 6 and Experimental Group 5 is that the average flow velocity at the nozzle 41 orifice is 0.5 m / s.

[0132] Experimental Group 7: The difference between Experimental Group 7 and Experimental Group 5 is that the average flow velocity at the nozzle 41 orifice is 0.05 m / s.

[0133] Experimental Group 8: The difference between Experimental Group 8 and Experimental Group 5 is that the second duration is 80 seconds.

[0134] Experimental Group 9: The difference between Experimental Group 9 and Experimental Group 5 is that the third duration is 12 seconds.

[0135] Experimental Group 10: The difference between Experimental Group 10 and Experimental Group 5 is that the third duration is 3 seconds.

[0136] The chloroauric acid yield and current efficiency of experimental groups 1 to 10 are detailed in Table 1. The current efficiency is the percentage of the theoretically required electricity for effective gold dissolution relative to the actual total electricity consumed.

[0137] Table 1. Chloroauric acid yield and current efficiency in experimental groups 1 to 10

[0138] .

[0139] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A bidirectional pulse device, characterized in that, For generating bidirectional fluid pulses; the bidirectional pulse device includes: A bidirectional pump; the A port of the bidirectional pump is connected to a tailpipe, which is inserted into the fluid; the B port of the bidirectional pump is connected to a piping assembly, which is connected to at least one set of nozzle assemblies, which are placed in the fluid; Each nozzle assembly includes multiple nozzles, each nozzle comprising a converging section and a stabilizing section; the total cone angle of the converging section is less than 30°; the larger end of the converging section is connected to the piping assembly, and the smaller end of the converging section is connected to the stabilizing section; the length of the stabilizing section is greater than the length of the converging section; the spray direction of the nozzle of the stabilizing section forms an angle of -60° to -30° with the normal vector of the target area.

2. The bidirectional pulse device according to claim 1, characterized in that, It also includes a cleaning component, the cleaning component comprising: A three-way valve, the first end of which is connected to port B of the bidirectional pump, the second end of which is connected to the pipeline assembly, and the third end of which is connected to the cleaning pipeline, which is connected to the cleaning source, and a cleaning pump is installed on the cleaning pipeline.

3. The bidirectional pulse device according to claim 1, characterized in that, Also includes: At least one set of telescopic components, each set of said telescopic components including: Mounting bracket, wherein the mounting bracket is provided with a telescopic structure; The telescopic structure includes a limiting rod and a first mounting tube and a second mounting tube with telescopic sliding fit; one end of the first mounting tube is mounted on the mounting bracket, and the other end of the first mounting tube has a positioning through hole; one end of the second mounting tube is connected to the nozzle assembly, and the other end of the second mounting tube has a plurality of equally spaced adjustment through holes; the limiting rod passes through the positioning through hole and the adjustment through hole.

4. The bidirectional pulse device according to claim 1, characterized in that, Each of the nozzle assemblies further includes: The mounting frame has a ring array, which includes multiple mounting rings arranged along the Z-axis. The central axis of the mounting rings forms an angle of -60° to -30° with the normal vector of the mounting frame. The first side of the mounting ring is connected to the pipeline assembly, and the second side of the mounting ring is connected to the nozzle.

5. The bidirectional pulse device according to claim 1, characterized in that, The piping assembly includes: A first pipeline, one end of which is connected to the bidirectional pump, and the other end of which is connected to at least one set of second pipelines, each set of second pipelines being connected to the nozzle, wherein the inner diameter of the second pipeline is the same as the inner diameter of the large end of the tapered section.

6. The bidirectional pulse device according to claim 5, characterized in that, The second pipeline has multiple mounting holes along the Z-axis direction, and the mounting holes are used to install the nozzle; The angle between the axis of symmetry of the mounting hole and the XOY plane is -60° to -30°.

7. An apparatus for preparing chloroauric acid, characterized in that, include: An electrolytic cell, wherein a first mounting buckle is provided on the cell wall furthest from the cathode in the anode chamber of the electrolytic cell; The bidirectional pulse device according to any one of claims 1 to 6, wherein: the tail tube is provided with a first buckle, the first buckle is connected to the first mounting buckle, and the end of the tail tube extends into the electrolyte; It includes multiple nozzle assemblies; at least some of the nozzle assemblies are equally spaced on the side of the anode facing the cathode; the vertical distance between the nozzle of the nozzle assembly and the anode surface is 2mm to 3mm, and the spray direction of the nozzle orifice forms an angle of -60° to -30° with the normal vector of the anode.

8. A method for preparing chloroauric acid, characterized in that, The preparation method is based on the chloroauric acid preparation equipment as described in claim 7; the preparation method includes performing cyclic steps multiple times until a predetermined electrolysis endpoint is reached. The cyclic steps include: Forward electrolysis step: Turn off the bidirectional pump, use gold as the anode, graphite as the cathode, and a saturated calomel electrode as the reference electrode, control the potential of the anode relative to the reference electrode to +1.25V, perform electrolytic oxidation of gold to prepare chloroauric acid, and continue for the first duration; Reverse perturbation step: Start the bidirectional pump and control the potential of the anode relative to the reference electrode to -0.3V; the reverse perturbation step includes the following steps performed sequentially: Flushing sub-step: Control the bidirectional pump to rotate in the first direction, use the tailpipe to draw electrolyte, and spray it onto the anode surface through the nozzle; during the flushing sub-step, the first total flow rate of the pipeline assembly is the first target total flow rate, and lasts for a second duration; Back-suction step: Control the bidirectional pump to rotate in a second direction opposite to the first direction, so that the nozzle produces a suction effect, forming a flow field pointing towards the nozzle near the anode surface, which is used to guide the gold species that were stripped or suspended near the anode surface in the flushing step away, so as to prevent them from being adsorbed on the anode surface again; in the back-suction step, the second total flow rate of the tailpipe is the second target total flow rate, and it lasts for a third duration.

9. The method for preparing chloroauric acid according to claim 8, characterized in that, The reverse perturbation step further includes: Potential buffering step: Switch the potential of the anode relative to the reference electrode from +1.25V to 0V, start the bidirectional pump to rotate in the first direction, and when the first total flow rate of the bidirectional pump is greater than or equal to 90% of the first target total flow rate, switch the potential of the anode relative to the reference electrode from 0V to -0.3V.

10. The method for preparing chloroauric acid according to claim 8, characterized in that, The first duration is 25 to 35 minutes; The second duration is 90 to 150 seconds; The third duration is 5 to 10 seconds; The first target total flow rate results in an average flow velocity of 0.10 m / s to 0.40 m / s for each of the nozzles. The second target total flow is 20% to 40% of the first target total flow; The predetermined electrolysis endpoint includes a cumulative dissolved gold mass greater than or equal to 80% of the initial anode mass, or an average current in the forward electrolysis steps of three consecutive cycles less than or equal to 50% of the average current in the forward electrolysis steps of the first cycle. The gold species include at least one of the following: tetrachloroalloy ion, trichloro-1-hydroxyalloy ion, dichloro-2-hydroxyalloy ion, hydrated chloroauric acid molecule, hydrated chloroauric acid crystal, monochloroalloy ion, gold oxide, gold hydroxy oxide, gold chloride oxide mixed phase, and metallic gold microparticles.

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