Device and method for preparing nanodiamond powder by underwater electroexplosion of metal wire

Abstract

The present invention discloses a device and a method for preparing nanodiamond powder by electro-exploding a metal wire in water. A wire feeding mechanism is fixedly installed in an explosion container, and the wire feeding mechanism is connected with a metal wire. Two electrodes are arranged in the explosion container, and the two electrodes are connected with a high-voltage pulse capacitor, and the high-voltage pulse capacitor is connected with a high-voltage DC power supply. The preparation method includes: grinding amorphous carbon solid waste; washing the remaining carbon source powder with deionized water; preparing a carbon source powder mixed solution with deionized water; feeding the mixed solution into the explosion container, connecting the two electrodes with the two ends of the metal wire, charging the high-voltage pulse capacitor by the high-voltage DC power supply for explosion, discharging the mixed solution inside the explosion container from the discharge port, and separating out the solid; removing the nano-metal powder in the solid; and drying to obtain the nanodiamond powder. Using amorphous carbon solid waste as a raw material, the raw material is synthesized into nanodiamond powder by the high temperature and high pressure generated by electro-explosion, realizing the resource utilization of solid waste and reducing pollution and carbon emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of nano-diamond powder preparation, and particularly to an apparatus and method for preparing nano-diamond powder by electro-exploding a metal wire in water. Background Art

[0002] Nano-diamond is a high-value industrial material and can be used in ultra-precision polishing, lubricating oil additives, biomedicine, stealth materials, etc. The existing widely used methods for preparing nano-diamond are mostly high-temperature and high-pressure synthesis methods, such as TNT explosion synthesis, high-temperature and high-pressure autoclave synthesis, etc. However, the former method has high costs and is difficult to be widely promoted and industrialized; the latter is mostly used for small-scale laboratory applications, with complex processes and low yields.

[0003] The electro-explosion of a metal wire refers to a physical phenomenon in which, in a certain medium (such as inert gas, water, etc.) environment, when a strong pulsed current passes through a conductor wire, the physical state of the conductor material itself changes rapidly, and electrical energy is quickly converted into other forms of energy (such as thermal energy, plasma radiation energy, shock wave energy, etc.). The preparation of nano-powder materials by electro-explosion can be used as a pure physical method (such as preparing nano-powder in an inert gas environment) or as a comprehensive preparation method (by controlling the chemical reaction between the high-temperature and high-pressure metal vapor and the environmental medium after the explosion). Currently, there is no report at home and abroad on the apparatus and process for synthesizing nano-diamond powder from amorphous carbon solid waste using the high temperature and high pressure generated by electro-explosion.

[0004] The main technical defects of the existing nano-diamond powder preparation technology are as follows:

[0005] Firstly, from the process aspect: the existing processes for synthesizing nano-diamond powder often have problems such as high costs, the preparation process being limited by the site and equipment, being unable to balance economy and yield, and the industrialization promotion path being unclear.

[0006] From the energy consumption aspect: the high-temperature and high-pressure autoclave method has high energy consumption and complex preparation, which is not conducive to popularization and application under the current international background of carbon neutrality.

[0007] From the reactor aspect: both the TNT explosion method and the high-temperature and high-pressure autoclave method have strict requirements for the reactor (temperature and pressure resistance, sufficient firmness and stability).

[0008] From the cost aspect: the TNT explosion method with a large synthesis output has high costs and cannot be promoted and applied. Summary of the Invention

[0009] The purpose of the present invention is to provide an apparatus and method for preparing nano-diamond powder by electro-exploding a metal wire in water to solve the problems existing in the above-mentioned prior art.

[0010] To achieve the above object, the present invention provides the following solutions: The present invention provides a device for preparing nanodiamond powder by electro-exploding a metal wire in water, including an explosion container. A wire feeding mechanism is fixedly arranged at the top outside of the explosion container. The wire feeding mechanism is connected with a metal wire, and the metal wire is located inside the explosion container. Two electrodes are arranged inside the explosion container. The two electrodes are electrically connected to a high-voltage pulse capacitor, and the high-voltage pulse capacitor is electrically connected to a high-voltage DC power supply. An inlet is opened on one side of the explosion container, and an outlet is opened at the bottom of the explosion container. Both the inlet and the outlet are communicated with the inside of the explosion container.

[0011] Preferably, a first observation window and a second observation window for observing the inside of the explosion container are arranged at the bottom of the explosion container.

[0012] Preferably, the two electrodes are slidably connected to the inside of the explosion container.

[0013] Preferably, the explosion container is made of stainless steel material.

[0014] A method for preparing nanodiamond powder by electro-exploding a metal wire in water includes the following steps:

[0015] a. Crush and grind the amorphous carbon solid waste, and remove large particles and impurities by screening.

[0016] b. Wash the remaining carbon source powder with deionized water, and precipitate and separate to remove the abrasive particles of the residual amorphous carbon solid waste.

[0017] c. Prepare a carbon source powder mixture with deionized water.

[0018] d. Feed the mixture into the explosion container through the inlet, and the automatic wire feeding mechanism automatically feeds the metal wire into the container. Adjust the two electrodes to be respectively connected to both ends of the metal wire. After the electrodes are in contact and connected with the metal wire, the high-voltage DC power supply charges the high-voltage pulse capacitor. After charging is completed, an explosion occurs. Repeat the process of this stage, and electro-explode the metal wire repeatedly in the mixture.

[0019] e. After completing the explosion process in step d, the mixture inside the explosion container is discharged from the outlet, and the mixture is filtered to separate the solid.

[0020] f. Remove the nano-metal powder generated due to the electro-explosion of the metal wire in the solid.

[0021] g. Remove the residual amorphous carbon particles in the solid.

[0022] h. The remaining solid particles are washed and dried to obtain nanodiamond powder.

[0023] Preferably, in step d, the automatic wire feeding mechanism automatically feeds the metal wire to a position 200 mm below the liquid level in the container.

[0024] Preferably, in step f, pickling or electrolysis is used to remove the nano metal powder generated by the electro-explosion of the metal wire in the solid.

[0025] Preferably, in step g, any one of perchloric acid, sulfuric acid, nitric acid, and potassium permanganate is used to dissolve the amorphous carbon particles.

[0026] Preferably, the particle size of the nano diamond powder obtained in step h is controlled within 10 - 50 nm.

[0027] The present invention discloses the following technical effects: The present invention designs a device and method for preparing nano diamond powder by electro-exploding metal wire in water. Using amorphous carbon solid waste as raw material, the raw material is synthesized into nano diamond powder through the high temperature and high pressure generated by electro-explosion, realizing the resource utilization of solid waste and reducing pollution and carbon emissions; The present invention is the first in China to use electro-explosion of metal wire in water instead of explosive explosion to prepare nano diamond powder; Convert the difficult-to-treat amorphous carbon solid waste into high-value-added nano diamond powder; The production process of this device is safer and more efficient, and can achieve unattended production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a schematic structural diagram of the electro-explosion device in water of the present invention;

[0030] Figure 2 It is a process flow chart for preparing nano diamond powder of the present invention.

[0031] Wherein: 1, automatic wire feeding mechanism; 2, explosion container; 3, electrode; 4, feed inlet; 5, first observation window; 6, discharge outlet; 7, second observation window; 8, high voltage DC power supply; 9, high voltage pulse capacitor; 10, metal wire. DETAILED DESCRIPTION OF THE INVENTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Embodiment 1: In this embodiment of the electro-explosion method, taking the metal wire 10 as an example, iron wires with a diameter of 0.5 - 1 mm and a purity of 90 - 99.5% can be used; the distance between the electrodes 3 is set to be adjustable within 0 - 200 mm; the set value of the power supply charging voltage is 20 - 35 kV; the explosion interval is set to 0.5 - 10 seconds.

[0035] Refer to Figure 1-2 , this embodiment provides a device for preparing nanodiamond powder by electro-exploding a metal wire in water, including an explosion container 2. A wire feeding mechanism is fixedly arranged at the top outside the explosion container 2. The wire feeding mechanism is connected to a metal wire 10, and the metal wire 10 is located inside the explosion container 2. Two electrodes 3 are arranged inside the explosion container 2. The two electrodes 3 are electrically connected to a high-voltage pulse capacitor 9. After being charged by the power supply, it instantaneously discharges through the electrodes 3 to connect the metal wire 10. The electric energy accumulated in the capacitor is instantaneously applied to the metal wire 10, causing it to overload and undergo an electro-explosion. The high-voltage pulse capacitor 9 is electrically connected to a high-voltage DC power supply 8, and the high-voltage DC power supply 8 charges the high-voltage pulse capacitor 9 to provide the basic energy for the explosion. An inlet 4 is opened on one side of the explosion container 2, and an outlet 6 is opened at the bottom of the explosion container 2. Both the inlet 4 and the outlet 6 are communicated with the inside of the explosion container 2.

[0036] Advantages of the electro-explosion method:

[0037] High energy conversion efficiency. It is easy to convert electrical energy into heat energy relying on the resistance of the metal wire 10 in the discharge circuit; the particle size distribution of the prepared material is more uniform and the purity is high. Pulsed discharge can simultaneously vaporize the entire metal wire 10, and the vaporization effect is more uniform than that obtained by vaporizing from the metal surface with pulsed laser and particle beam. By controlling the surrounding environmental medium well, high purity of the nano powder can be ensured (the purity of the metal nano material can reach 99%); the process parameters are convenient to adjust. By adjusting parameters such as capacitance, charging voltage, and the size of the explosion wire, the particle size can be effectively controlled; the method has strong versatility. Various types of nano powder materials can be prepared by the electro-explosion method; no harmful substances are produced and the environment is not damaged, which is a "green" method for preparing nano powder.

[0038] The automatic wire feeding mechanism 1 of this device can feed the target metal wire 10 into the explosion container 2 according to the set automation program, and control the explosion area by adjusting the positions of the electrodes 3 at both ends of the metal wire 10. The automatic wire feeding mechanism 1 of this device can use a motor to drive the rotation of the rotating shaft for wire feeding, where the metal wire 10 is wound around the rotating shaft or the roller, or manual wire feeding can also be used for wire feeding; existing wire feeding mechanisms, devices, etc. can all be used as the wire feeding mechanism of the present invention.

[0039] There is sufficient explosion space reserved inside the explosion space. The bottom of the explosion container 2 is provided with a first observation window 5 and a second observation window 7 for observing the inside of the explosion container 2. The two electrodes 3 are slidably connected to the inside of the explosion container 2. The explosion container 2 is made of stainless steel material. Operators can observe the inside of the explosion container 2 through the first observation window 5 and the second observation window 7, and can conduct multi-directional observations from the bottom of the explosion container 2 to monitor the preparation process in real time.

[0040] A method for preparing nanodiamond powder by electro-exploding a metal wire 10 in water includes the following steps:

[0041] a. Crush and grind the amorphous carbon solid waste, and remove large particles and impurities by screening; (The production raw material used in the process of this device is solid waste containing a large amount of amorphous carbon, such as the solid waste powder generated during the processing of carbon fiber composites, or the powder ground from block waste, or the solid waste generated during the processing of carbon nanomaterials such as carbon nanotubes and graphene.)

[0042] b. Wash the remaining carbon source powder with deionized water, and precipitate and separate to remove the abrasive particles of the residual amorphous carbon solid waste.

[0043] c. Prepare a carbon source powder mixture with deionized water.

[0044] d. Feed the mixture into the explosion container 2 through the feed port 4, and the automatic wire feeding mechanism 1 automatically feeds the metal wire 10 to a position 200 mm below the liquid level in the container. Adjust the two electrodes 3 to be respectively connected to both ends of the metal wire 10. After the electrode 3 is in contact and connected with the metal wire 10, the high-voltage DC power supply 8 charges the high-voltage pulse capacitor 9. After charging is completed, an explosion occurs; repeat the process of this stage, and repeatedly explode the metal wire 10 in the mixture.

[0045] e. After completing the explosion process in step d, the mixture inside the explosion container 2 is discharged from the discharge port 6, and the mixture is filtered to separate the solid.

[0046] f. Use the pickling method or the electrolysis method to remove the nano-metal powder generated due to the electro-explosion of the metal wire 10 in the solid; the pickling method usually uses hydrochloric acid, sulfuric acid, nitric acid, etc.

[0047] g. Dissolve the residual amorphous carbon particles in the solid with any one of perchloric acid, sulfuric acid, nitric acid, and potassium permanganate;

[0048] h. The remaining solid particles are washed and dried to obtain nano-diamond powder, and the particle size can be adjusted to be between 50 - 10 nm by controlling the process parameters.

[0049] The present invention realizes the substitution of production raw materials. In order to embody the concept of solid waste resource utilization and pollution reduction and carbon emission reduction, the present invention uses amorphous carbon solid waste as the production raw material. In the actual preparation of diamond powder, high-purity graphite powder can also be used as the raw material. Substitution of the explosion method. The present invention uses the electro-explosion method to generate high temperature and high pressure. If there is a newly invented technology that can generate high temperature and high pressure instantly, it can also be substituted. Substitution of some links in the complete production process. The production process of the present invention purifies the powder step by step through each link and discharges impurities. If the purification link is integrated and different purification methods and agents are used, it can also be substituted.

[0050] Example 2: The difference between this example and Example 1 is only that this example uses a metal foil instead of the metal wire 10 to prepare nano-diamond powder; the device used for preparation and the method steps for preparation are the same as those of the method using the metal wire 10.

[0051] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0052] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing nanodiamond powder by electro-exploding a metal wire in water, and an apparatus for preparing nanodiamond powder by electro-exploding a metal wire in water, characterized in that: The device for preparing nanodiamond powder by electro-exploding a metal wire in water includes an explosion container (2). A wire feeding mechanism is fixedly arranged at the top outside the explosion container (2). The wire feeding mechanism is connected to a metal wire (10), and the metal wire (10) is located inside the explosion container (2). Two electrodes (3) are arranged inside the explosion container (2). The two electrodes (3) are electrically connected to a high-voltage pulse capacitor (9), and the high-voltage pulse capacitor (9) is electrically connected to a high-voltage DC power supply (8). An inlet (4) is provided on one side of the explosion container (2), and an outlet (6) is provided at the bottom of the explosion container (2). Both the inlet (4) and the outlet (6) are communicated with the inside of the explosion container (2). The method for preparing nanodiamond powder by electro-exploding a metal wire in water includes the following steps: a. Crush and grind the amorphous carbon solid waste, and remove large particles and impurities by screening; b. Wash the remaining carbon source powder with deionized water, and precipitate and separate to remove the abrasive particles of the residual amorphous carbon solid waste; c. Prepare a carbon source powder mixture with deionized water; d. Feed the mixture into the explosion container (2) through the inlet (4), and the automatic wire feeding mechanism (1) automatically feeds the metal wire (10) into the container. Adjust the two electrodes (3) to be respectively connected to both ends of the metal wire (10). After the electrode (3) is in contact and connected with the metal wire (10), the high-voltage DC power supply (8) charges the high-voltage pulse capacitor (9). After charging is completed, an explosion occurs. Repeat the process of step d, and repeatedly explode the metal wire (10) in the mixture; e. After the explosion process in step d is completed, the mixture inside the explosion container (2) is discharged from the outlet (6), and the mixture is filtered to separate the solid; f. Remove the nano-metal powder generated by the electro-explosion of the metal wire (10) in the solid; g. Remove the residual amorphous carbon particles in the solid; h. The remaining solid particles are washed and dried to obtain nanodiamond powder.

2. The method for preparing nano-diamond powder by electro-exploding metal wire in water according to claim 1, characterized in that: A first observation window (5) and a second observation window (7) for observing the inside of the explosion container (2) are provided at the bottom of the explosion container (2).

3. The method for preparing nanodiamond powder by electro-exploding a metal wire in water according to claim 1, characterized in that: The two electrodes (3) are slidably connected to the inside of the explosion container (2).

4. The method for preparing nanodiamond powder by electro-exploding a metal wire in water according to claim 1, characterized in that: The explosion container (2) is made of stainless steel material.

5. The method for preparing nano-diamond powder by electro-exploding a metal wire in water according to claim 1, wherein: In step d, the automatic wire feeding mechanism (1) automatically feeds the metal wire (10) to a position 200 mm below the liquid level in the container.

6. The method for preparing nanodiamond powder by electro-exploding a metal wire in water according to claim 1, wherein: In step f, the nano-metal powder generated by the electro-explosion of the metal wire (10) in the solid is removed by pickling or electrolysis.

7. The method for preparing nanodiamond powder by electro-exploding a metal wire in water according to claim 1, wherein: In step g, any one of perchloric acid, sulfuric acid, nitric acid, and potassium permanganate is used to dissolve the amorphous carbon particles.

8. The method for preparing nanodiamond powder by electro-exploding a metal wire in water according to claim 1, wherein: The particle size of the nanodiamond powder obtained in step h is controlled within 10 - 50 nm.

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