Method for recovering nickel and verifying whether recovered nickel can be used for preparing diamond

Abstract

The invention discloses a method for recovering nickel and verifying whether the recovered nickel can be used for preparing diamond, which utilizes equipment such as an intermediate frequency furnace and the like to secondarily utilize waste nickel (Ni) after diamond synthesis to prepare new recovered nickel (Ni), thereby effectively improving the defects of low production benefit of enterprises, low production cost and the like caused by high production raw material cost in the diamond manufacturing process. According to the method and the device, the problems of the nickel (Ni) treatment mode and cost after diamond production are solved, the production benefits of enterprises can be effectively improved, the nickel (Ni) is repeatedly utilized, and damage to the environment is reduced. And meanwhile, the nickel (Ni) is utilized for two times and even multiple times, so that the method is a technical breakthrough in the technical field of diamonds, and a novel idea is provided for the same industry.

Description

Technical Field

[0001] This invention relates to the field of diamond synthesis technology, and in particular to a method for recovering nickel and verifying whether recovered nickel can be used to prepare diamond. Background Technology

[0002] Nickel (Ni) can form a stable alloy interface with carbon atoms in diamond, thereby improving the bonding strength between diamond tools and the metal matrix. This strong bonding makes diamond tools less prone to spalling during processing, extending tool life and cutting efficiency. The addition of nickel can significantly improve the bending and compressive strength of diamond tools. Through infiltration in a high-temperature molten state, nickel interacts with the diamond surface to form a stable alloy interface, enhancing the bonding strength between diamond particles and the tool as a whole. Nickel (Ni) powder has excellent thermal conductivity, effectively transferring heat from diamond particles to the tool matrix, preventing diamond from burning or deforming due to high temperatures. This helps improve the wear resistance and lifespan of diamond tools. Nickel (Ni) powder can form a protective film, preventing diamond particles from reacting with oxygen in the air, reducing diamond oxidation and damage. This helps maintain the sharpness and cutting performance of diamond particles. The addition of nickel (Ni) powder can also increase the hardness, strength, and toughness of diamond tools, improving their compressive and impact resistance. This allows diamond tools to maintain stable performance under high loads and harsh environments. Using recycled nickel (Ni) reduces the need for new nickel (Ni), thereby lowering production costs. Recycling resources is not only environmentally friendly but also brings economic benefits to businesses.

[0003] Currently, the high cost of raw materials in diamond production leads to low production efficiency for enterprises. The methods of handling nickel (Ni) after diamond production are not environmentally friendly and can easily cause environmental pollution. There are also problems such as the inability to reuse nickel (Ni) and high costs. Summary of the Invention

[0004] The purpose of this invention is to provide a method for recycling nickel and a method for verifying whether recycled nickel (Ni) can be used to prepare diamonds. This effectively improves the low production efficiency of enterprises due to high raw material costs during diamond production, as well as the methods and costs of nickel (Ni) disposal after diamond production. It can effectively improve enterprise production efficiency and adhere to green principles by reusing nickel (Ni), reducing environmental damage. Furthermore, the secondary and multiple uses of nickel (Ni) represent a technological breakthrough in the field of diamond technology, providing a new approach for the industry.

[0005] This invention discloses a method for recovering nickel, comprising the following steps:

[0006] Step 1: Extract waste nickel from the treated electrolyte after diamond production and reprocess it into a catalyst;

[0007] Step 2: Mix the graphite and masterbatch powder that have been baked in a high-temperature oven with the catalyst in a certain proportion;

[0008] Step 3: Granulate the mixed materials;

[0009] Step 4: The granulated material is initially pressed to form graphite cores;

[0010] Step 5: Place the initially pressed graphite core into a vacuum furnace for firing.

[0011] Step 6: Press the fired core column a second time;

[0012] Step 7: Assemble the core column, which has been mixed, granulated, pressed, and fired, with the pyrophyllite-related accessories;

[0013] Step 8: Conduct a machine test on the assembled assembly blocks;

[0014] Step 9: After the core is completed, acid pickling is performed to obtain the data of the synthesized diamond;

[0015] Step 10: Compare the data of diamonds made from recycled nickel and diamonds made from normal nickel under multiple sets of the same pressure and power to verify whether recycled nickel is suitable for making diamonds.

[0016] Preferably, the process for recycling waste nickel in step 1 is as follows: pretreatment → high-temperature purification → nickel content analysis and cutting → formula calculation → alloy smelting and water atomization treatment.

[0017] Preferred from any of the above schemes, the specific process for recycling waste nickel in step 1 is as follows: ① Pre-treatment: a1, demolding the recycled electrolytic waste nickel plates; b1, pre-treating the recycled nickel by baking it at a high temperature above 180℃ in a high-temperature oven. ② High-temperature purification, using a medium-frequency furnace, with a purification temperature of 1400-1600℃: a2, alloying the pre-treated and baked recycled nickel plates at high temperature; b2, cooling the alloyed molten iron in a mold. ③ Nickel (Ni) content analysis and cutting: a3, performing spectral testing on the demolded bars using a spectrometer to determine the distribution and proportion of iron-nickel (Ni) content; b3, cutting and storing the bars using gantry shears. ④ Calculating the proportion: a4, calculating the formula based on the proportion of recycled nickel and weighing the formula. ⑤ Smelting alloy and water atomization treatment: a5, smelting and alloying the prepared raw materials; b5, atomizing them into powder; c5, baking and sieving.

[0018] The intermediate frequency furnace and its subsequent steps are as follows:

[0019] A. Operation of medium-frequency furnace:

[0020] (1) Turn on the circulating water and check whether each drain outlet is draining normally;

[0021] (2) Clean up debris inside the furnace;

[0022] (3) Check whether the switches of the medium frequency furnace are all in the off position and whether the frequency knob is in the zero position;

[0023] (4) Turn on the closing power supply, rotate the switch pause knob to pause, and press the main power closing button. You will hear a click, indicating that the power switch has been successfully closed.

[0024] (5) Rotate the pause knob to the on position, then slowly rotate the frequency knob until it reaches the maximum.

[0025] (6) Check whether the high-pressure pump water circuit switch is open and whether the drainage is smooth;

[0026] (7) Turn on the nitrogen flow meter inside the atomizing can to 6m³;

[0027] (8) Tilting the rotating furnace opening, place the iron rod to be fired and the remaining materials in, and cover with a fiberglass pad;

[0028] (9) Because the furnace opening diameter is small and the material can only be fed in a limited way, the material should be added and melted again after the furnace has melted.

[0029] (10) When adding fuel in the middle, tilt the furnace opening slightly and wear fireproof equipment;

[0030] (11) When the ammeter of the medium frequency furnace slowly drops, it means that the iron rod has turned red and has melted when it slowly rises.

[0031] (12) Wear protective gear and continuously observe the changes in molten iron and the combustion temperature through goggles during the process;

[0032] (13) Place the dried strainer at the atomizing feed inlet, ready to pour the material;

[0033] (14) When the molten iron appears light yellow and there are no snowflake-like floating particles when viewed through the goggles, it is ready to be poured out of the furnace;

[0034] (15) Before unloading, turn on the high-pressure pump and the person receiving the material should check whether the pressure gauge of the high-pressure pump is within the range.

[0035] (16) Pour the material at a constant and slow speed during the pouring process. Do not speed up or stop suddenly to prevent the outside from being damaged.

[0036] (17) After the contents have been poured out, the leaking pot should be repaired, the residue removed, and the leak replaced before it can be used again.

[0037] B. Material receiving operator's operation:

[0038] (1) Requirements for water injection in atomizing irrigation system: turn on the water injection pump and observe the water level rise until the water level reaches the water level mark line, then turn off the water injection pump.

[0039] (2) When you hear the high-pressure pump start, the material pouring begins. Check the high-pressure pump pressure regularly to see if it is within the allowable range.

[0040] (3) When the high-pressure pump is turned off, the material pouring above is finished, and the receiving worker starts to release the material. If the material cannot be released, shake the water pipe up and down.

[0041] (4) Place the discharged water into the collection tank for sedimentation and adsorption. Wait five minutes and observe the water clarity. Discharge the water once it meets the discharge standard. Continue to refill the atomizing tank with water during the process.

[0042] (5) After the water has been drained, proceed with the material collection process. Use a shovel to collect the material into a tray;

[0043] C. Vacuum oven operation:

[0044] (1) Clean up debris inside the furnace;

[0045] (2) Turn on the oven and set the temperature to 175℃;

[0046] (3) Measure the furnace temperature. At this time, the keypad displays the furnace temperature.

[0047] (4) Arrange the material received on the tray neatly inside the furnace, close the furnace door, and check whether the furnace venting valve is closed;

[0048] (5) Open the vacuum pump pipeline valve in front of the oven, turn on the circulating water valve, set the water ring pump time relay, and start vacuuming;

[0049] (6) Observe whether the pointer of the vacuum pressure gauge moves;

[0050] (7) Set the time relay time according to the thickness and humidity of the raw material until the raw material is dry (it should be consistent with the time setting of the water ring pump).

[0051] In any of the above schemes, it is preferred to use a medium-frequency furnace for high-temperature purification, with a purification temperature of 1400-1600℃.

[0052] Specifically, the purification temperature can be any value within the range of 1400-1600℃, such as 1400℃, 1450℃, 1500℃, 1550℃, or 1600℃.

[0053] In any of the above schemes, it is preferred to use a medium-frequency furnace and a high-pressure pump for alloy melting and water atomization treatment.

[0054] In any of the above schemes, the preferred method is that in step 2, the mass mixing ratio of graphite + masterbatch to catalyst is 4:6 (using the same weight of graphite and masterbatch, but one using a normal catalyst and the other using a recycled nickel catalyst). When baking the graphite and masterbatch in a high-temperature oven, the temperature should be ≥180℃ and the time ≥6 hours. After preparation, the materials are added to a multi-dimensional mixer and run for 6-8 hours. Too short a running time can easily lead to uneven mixing of the three components, while too long a running time can cause the catalyst powder, being heavier than the graphite and masterbatch, to disperse entirely on the periphery, resulting in a thinner consistency. Both of these factors will affect the final quality of the synthesized diamond.

[0055] In any of the above schemes, the preferred method is that in step 2, the mass ratio of graphite + masterbatch to catalyst is 4:6, and the graphite and masterbatch are baked in a high-temperature oven at 180°C for 6 hours. Too short a baking time can lead to uneven mixing of the three components, while too long a baking time can cause the catalyst powder, being heavier than the graphite and masterbatch, to disperse entirely on the periphery, resulting in a thinner mixture. Both of these factors will affect the final quality of the synthesized diamond.

[0056] In any of the above embodiments, it is preferred that, in step 3, granulation is completed on a granulator, and the mixed material is added to the granulator for two granulation passes. The reason for granulation twice is to control the density. If granulation is done only once, the density will be too low, requiring a large pressing pressure. If granulation is done too many times, the density may be too high, resulting in a low pressing height. Both too low and too high density will affect the subsequent pressing.

[0057] In any of the above-mentioned schemes, the preferred embodiment is that, in step 4, the weight range and specifications of the initially pressed graphite core are: 42.5×35mm, weight between 149-149.2g, and diameter 41.4mm. Controlling the weight to 149-149.2g is to maintain an appropriate weight after vacuum furnace sintering to provide a threshold for subsequent secondary pressing. If the weight is too heavy, the subsequent pressing height will be too high; if the weight is too light, the subsequent pressing height will be too low, both of which will affect the core specifications and thus the final diamond synthesis.

[0058] In any of the above schemes, the preferred method is that, in step 5, the vacuum furnace firing process when the pressed graphite core is placed in a vacuum furnace for firing is as follows: a. After 30 minutes, the temperature is raised to 400°C and held for 15 minutes; b. After 180 minutes, the temperature is raised to 900°C and held for 15 minutes; c. After 120 minutes, the temperature is raised to 1100°C and held for 720 minutes; d. After heating is completed, the temperature naturally drops to 900°C, nitrogen is started, the blower is turned on, and nitrogen is replenished periodically after the blower is started.

[0059] The primary purpose of the heating process is to reduce the oxides of elements such as Fe and Ni in the catalyst of the core column. The addition of inert nitrogen gas at 900℃ is to increase the cooling rate, prevent oxidation, and replenish nitrogen, making the synthesized diamond more golden and translucent.

[0060] In any of the above embodiments, it is preferred that, in step 6, when the fired core column is pressed a second time, the pressing weight is 148.2-148.3g, the diameter is 42.4-42.5mm, and the height is 34.9±0.1mm. This size can perfectly fit with assembly accessories such as pyrophyllite.

[0061] In any of the above schemes, it is preferred that, in step 7, the pyrophyllite needs to undergo pre-treatment in an oven, the treatment method including: a. heating from room temperature to 150℃ in 90 minutes and holding for 240 minutes; b. heating from 150℃ to 200℃ in 90 minutes and holding for 240 minutes; c. heating from 200℃ to 250℃ in 90 minutes and holding for 240 minutes; d. heating from 250℃ to 280℃ in 90 minutes and holding for 240 minutes; e. naturally cooling from 280℃ to 60℃ and continuously holding at that temperature.

[0062] Pyrophyllite (Al2Si4O) 10 (OH)2) is a layered silicate mineral with excellent thermal stability and mechanical strength under high temperature and high pressure conditions. The main purpose of baking pyrophyllite in an oven is: (1) to remove moisture (including adsorbed water and structural water). Adsorbed water (surface water): Pyrophyllite will adsorb moisture from the air in the natural environment. High temperature baking (usually 200-300℃) can remove this part of the water. If the residual moisture evaporates when heated in the high pressure chamber, it may cause a sudden increase in vapor pressure, leading to pyrophyllite cracking or unstable pressure in the synthesis chamber. Structural water (hydroxyl OH) - The chemical structure of pyrophyllite contains hydroxyl groups (Al2Si4O). 10 (OH)2), at higher temperatures (such as above 500℃), will dehydroxylate and transform into an anhydrous phase (such as metakaolinite). However, in diamond synthesis, it is usually only necessary to remove adsorbed water to avoid excessive dehydration leading to embrittlement of pyrophyllite. (2) Improve pressure uniformity and sealing: Moisture will reduce the plasticity and fluidity of pyrophyllite. After baking, its deformation under high pressure becomes more uniform, which can better transmit pressure and seal the synthesis cavity to prevent pressure leakage. (3) Avoid contamination of synthesis raw materials: Moisture may participate in high-temperature chemical reactions and affect the diamond nucleation environment. It reacts with metal catalysts (such as Fe, Ni, Co) to cause oxidation and reduce catalytic efficiency. After baking, the chemical properties of pyrophyllite are more stable, reducing the introduction of impurities. 4. Process standardization requirements: The water content of different batches of pyrophyllite may vary greatly. Pre-baking can unify the material properties and ensure the repeatability and controllability of the synthesis process. The baked pyrophyllite needs to be sealed and stored to prevent re-absorption of moisture.

[0063] In any of the above solutions, it is preferred that, in step 7, the specifications of pyrophyllite and related accessories are as shown in the table below:

[0064]

[0065] In any of the above schemes, it is preferred that in step 8, the synthesis is carried out in a six-sided press, and the pressure required for synthesizing diamond is 5.5-6 GPa and the temperature is 1600-1800℃.

[0066] The process pressures are shown in the table below:

[0067]

[0068] The power parameters are shown in the table below:

[0069]

[0070] The total process time is 9 minutes and 17 seconds, with a heating time of 386 seconds. The pressure and power will be adjusted appropriately depending on the synthesis process.

[0071] In any of the above schemes, the preferred method for acid washing in step 9 includes: a. crushing the synthesized core column using a four-column press; b. pouring the crushed material into a glass beaker, adding concentrated sulfuric acid and concentrated hydrochloric acid in a volume ratio of 1:1, ensuring the amount of concentrated sulfuric acid and concentrated hydrochloric acid added covers the crushed material in the beaker as much as possible; c. heating the beaker in a heating furnace until the yellow smoke slowly turns into white smoke, then removing it from the heating furnace to cool; d. after the material in the beaker from step c has cooled to room temperature, washing it and adding aqua regia (concentrated hydrochloric acid: concentrated nitric acid volume ratio = 3:1), repeating step c; e. after step d is completed, repeating steps c and d until the graphite and catalyst encasing the diamond are removed; f. after cleaning, pouring the diamond into a beaker containing water and baking it until the acid from the acid washing is removed.

[0072] This invention also provides a verification method (a method for verifying whether recycled nickel (Ni) can be used to prepare diamond in the same way as normal nickel (Ni)). The method compares the data of diamonds prepared from recycled nickel and diamonds prepared from normal nickel under multiple sets of the same pressure and power to verify whether recycled nickel (Ni) is suitable for diamond production. The verification comparison is mainly based on three aspects: particle size, yield, and ash content. The final data is obtained by comparing diamonds synthesized from recycled nickel (Ni) and diamonds synthesized from normal nickel (Ni).

[0073] Preferably, the instrument for detecting ash in step 10 is a muffle furnace with a sintering temperature of 980℃. The principle of using a muffle furnace (box-type resistance furnace) to sinter diamond and detect its ash content is mainly based on the high-temperature oxidation method. By burning the carbon (C) component in the diamond, the remaining inorganic matter is the ash. The following are the detailed principles, steps and precautions: 1. Detection principle: High-temperature oxidation of diamond (carbon): Diamond will be completely oxidized to CO2 gas and volatilized under high temperature (usually 600–1000℃) and oxygen conditions. The reaction formula is: C (diamond) + O2 → CO2↑. Ash residue: Non-carbon components in diamond (such as metal catalysts, mineral inclusions, surface adsorbents, etc.) cannot be oxidized and volatilized. They are ultimately retained in the form of solid residue (ash). The ash content is calculated by weighing. 2. Experimental steps: (1) Sample preparation (sample form): Diamond powder, granules or broken synthetic diamond blocks. Pretreatment: Clean surface contaminants with organic solvents (such as acetone, alcohol). After drying, weigh accurately (recorded as m1, with an accuracy of 0.1 mg). (2) Muffle furnace sintering temperature setting: select 980℃ (to ensure complete oxidation of diamond and avoid excessive temperature leading to ash melting). Oxidation environment: introduce air or oxygen to accelerate oxidation (if the muffle furnace has no gas interface, the furnace can be opened to utilize natural convection). Time control: maintain high temperature for 2–4 hours until the sample reaches constant weight (no further mass loss). (3) Ash weighing and calculation: Cooling: turn off the muffle furnace and remove the crucible after the temperature drops below 200℃ (to avoid thermal shock cracking). Weighing: weigh the residue mass using a precision balance (recorded as m2).

[0074] Ash content calculation: Ash content (%) = .

[0075] Beneficial effects

[0076] This invention provides a method for recovering nickel and verifying whether recovered nickel (Ni) can be used to prepare diamonds. It effectively improves the low production efficiency of enterprises due to high raw material costs during diamond production, as well as the methods and costs of nickel (Ni) disposal after diamond production. It can effectively improve enterprise production efficiency and, in accordance with the green principles of the Civil Code, reuse nickel (Ni) to reduce environmental damage. Furthermore, the secondary and multiple uses of nickel (Ni) represent a technological breakthrough in the field of diamond technology, providing a new approach for the industry.

[0077] This invention utilizes equipment such as medium-frequency furnaces to recycle waste nickel (Ni) after diamond synthesis, producing new recycled nickel (Ni). This effectively improves enterprise production efficiency, reduces diamond raw material costs, and adheres to the green principles in the Civil Code, reusing nickel (Ni) and reducing environmental damage.

[0078] This invention utilizes the detection of diamonds synthesized from recycled nickel using a six-sided top press to verify the usability of recycled nickel (Ni) and compares it with diamonds synthesized from normal nickel. This provides a practical verification of the product and has stronger scientific validity and persuasiveness. Attached Figure Description

[0079] Figure 1 This is a diagram of the mixing process in Example 1;

[0080] Figure 2 This is a picture of the actual product after secondary granulation;

[0081] Figure 3 The graphite column after the second pressing;

[0082] Figure 4 The graphite column after synthesis;

[0083] Figure 5 A photograph of a normal nickel sample as seen with the naked eye;

[0084] Figure 6 Images of recovered nickel as seen with the naked eye;

[0085] Figure 7 This is a visual comparison of normal nickel on the left and recovered nickel on the right.

[0086] Figure 8 This is a normal electron microscope image of nickel.

[0087] Figure 9 This is an electron microscope image of the recovered nickel. Detailed Implementation

[0088] The following embodiments are further illustrations of the present invention and serve as explanations of the technical content of the present invention. However, the essence of the present invention is not limited to the embodiments described below. Those skilled in the art can and should know that any simple changes or substitutions based on the spirit of the present invention should fall within the protection scope claimed by the present invention.

[0089] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0090] Example 1

[0091] A method for recovering nickel and verifying whether recovered nickel can be used to prepare diamond includes the following steps: Step 1: Extracting waste nickel from the treated electrolyte after diamond production and reprocessing it into a catalyst: ① Pre-treatment: a1, demolding the recovered electrolytic waste nickel plate; b1, pre-treating the recovered nickel (Ni) by baking it at a high temperature above 180℃ for 3 hours in a high-temperature oven. ② High-temperature purification: a2, alloying the pre-treated and baked recovered nickel plate at a high temperature of 1400-1600℃ for 20 minutes using a medium-frequency furnace; b2, cooling the high-temperature alloyed molten iron to below 100℃ for 24 hours. ③ Nickel (Ni) content analysis and cutting: a3, performing spectral analysis on the demolded rods using a spectrometer to determine the distribution and proportion of iron-nickel (Ni) content to calculate the formula based on the nickel content proportion; b3, cutting and storing the rods using gantry shears. ④ Formula calculation: a4, calculating the formula based on the recovered nickel proportion and weighing the formula. ⑤ Alloy smelting and water atomization treatment: a5, use a medium frequency furnace and a high pressure pump to smelt and alloy the prepared raw materials; b5, atomize them into powder; c5, bake and sieve.

[0092] High-temperature purification is carried out using a medium-frequency furnace at a purification temperature of 1400-1600℃. The medium-frequency furnace and subsequent steps are as follows:

[0093] A. Operation of the medium frequency furnace: (1) Turn on the circulating water and check whether each drain outlet is draining normally. (2) Clean the debris inside the furnace. (3) Check whether the medium frequency furnace switches are all in the off state and whether the frequency knob is in the zero position. (4) Turn on the power supply, turn the switch pause knob to pause, and press the main power switch button. At this time, you will hear a click, and the power switch is successfully closed. (5) Rotate the switch pause knob to open. Slowly rotate the frequency knob until it reaches the maximum. (6) Check whether the high pressure pump water circuit switch is open and whether the drainage is smooth. (7) Turn on the nitrogen flow meter in the atomizing tank to 6m³. (8) Rotate the furnace opening at an angle to put in the iron rod to be fired and the remaining material, and cover it with a glass fiber pad. (9) Since the furnace opening diameter is small and the material can be put in a limited way, continue to add material to melt after it melts. (10) When adding material in the middle, tilt the furnace opening slightly and wear fireproof equipment. (11) When the medium frequency furnace ammeter slowly drops, it means that the iron rod has turned red and has melted when it slowly rises. (12) Wear protective gear and continuously check the changes in molten iron and combustion temperature through goggles during the process. (13) Place the baked molten iron in the atomizing charging port, ready to pour the material. (14) When the molten iron turns light yellow and there are no snowflake-like floating particles, it is ready to be poured into the furnace. (15) Before pouring the material, turn on the high-pressure pump and check whether the pressure gauge of the high-pressure pump is within the range. (16) Pour the material at a uniform and slow speed during the process, without sudden speeding or stopping, to prevent damage to the outside. (17) After pouring the material, the molten iron in the inlet should be repaired, slag removed, and the leak replaced before it can be used again.

[0094] B. Receiving worker's operation: (1) When the atomizing tank is filled with water, turn on the water pump and observe the water level rise. Stop the water pump when the water level reaches the mark. (2) When the high-pressure pump starts, the material pouring begins. Check the pressure of the high-pressure pump regularly to see if it is within the allowable range. (3) When the high-pressure pump is turned off, the material pouring ends. The receiving worker starts to release the material. If the material cannot be released, shake the water pipe up and down. (4) Put the released water into the collection tank for sedimentation and adsorption. Wait for five minutes and observe the clarity of the water. Release the water when it reaches the release standard. Continue to refill the atomizing tank with water during the process. (5) After the water is released, carry out the material collection process. Use a shovel to collect the material into the tray.

[0095] C. Vacuum oven operation: (1) Clean the debris inside the oven. (2) Turn on the oven and set the temperature to 175℃. (3) Measure the temperature inside the oven; the keypad will display the temperature inside the oven. (4) Arrange the material collected in the tray neatly inside the oven. Close the oven door and check if the oven vent valve is closed. (5) Open the vacuum pump pipeline valve before the oven. Open the circulating water valve and set the water ring pump time relay to start vacuuming. (6) Observe whether the pointer of the vacuum pressure gauge moves. (7) Set the time relay time according to the thickness and humidity of the raw material. Continue until the raw material is dry (it should be consistent with the water ring pump time setting). The obtained recycled nickel metal powder is as follows: Figure 3 As shown, Figure 4 For the comparison of recycled nickel and normal nickel.

[0096] Step two: After completing the nickel recovery process, the graphite and masterbatch powder, dried in a high-temperature oven, are mixed with the catalyst in a specific ratio. The graphite and masterbatch powder are then dried in a high-temperature oven at 180℃ for at least 6 hours. The mass mixing ratio of graphite, masterbatch powder, and catalyst is m(graphite + masterbatch powder):mcatalyst = 4:6. The same graphite and masterbatch powder are used, but one uses a normal catalyst and the other uses a nickel recovery catalyst. After preparation, the two materials are added to two multi-dimensional mixers and run for 6-8 hours (the mixing time is the same for both mixers). The mixing process is as follows: Figure 1 As shown.

[0097] Step 3: Granulate the mixed materials: Add the mixed materials to a granulator for two granulation processes, achieving a particle size of 3-4 mm. Figure 2 As shown.

[0098] Step four: The granulated material is initially pressed into graphite cores. The cores are 42.5×35mm in size, weighing between 149-149.2g, and approximately 41.4mm in diameter.

[0099] Step 5: After pressing, place the sample in a vacuum furnace for sintering.

[0100] Step six: After sintering, a second pressing is performed, with the pressure controlled at 14-15 MPa. The weight of the second pressing is 148.2-148.3 g, the diameter is 42.4-42.5 mm, and the height is 34.9 ± 0.1 mm. The graphite column after the second pressing is as follows: Figure 3 As shown.

[0101] Step 7: Press the 3-4mm secondary granules after mixing and granulation. The resulting graphite column will resemble... Figure 4 As shown, the fired core is assembled with pyrophyllite and other accessories;

[0102] The specifications for pyrophyllite and related accessories are shown in Table 1 below:

[0103] Table 1

[0104]

[0105] Step 8: Conduct a machine test on the assembled assembly blocks, with a pressure of 40-50.5-61.5 MPa and the power remaining constant.

[0106] The synthesis was carried out in a six-sided top press, and the process pressure and power parameters are shown in Tables 2 and 3 below:

[0107] Table 2

[0108]

[0109] Table 3

[0110]

[0111] The total process time is 9 minutes and 17 seconds, with a heating time of 386 seconds. The pressure and power will be adjusted appropriately depending on the synthesis process.

[0112] Step 9: After completing the diamond synthesis, perform acid washing: a. Crush the synthesized core using a four-column press; b. Pour the crushed material into a 5L glass beaker, add concentrated sulfuric acid and concentrated hydrochloric acid (volume ratio approximately 1:1), ensuring the concentrated sulfuric acid and hydrochloric acid completely cover the crushed material in the beaker; c. Heat the beaker in a furnace until the yellow smoke gradually turns into white smoke, then remove it from the furnace and cool it; d. After the material in the beaker from step c has cooled to room temperature, wash it and add aqua regia (concentrated hydrochloric acid: concentrated nitric acid volume ratio = 3:1), repeating step c; e. After step d is completed, repeat steps c and d until the graphite and catalyst coating the diamond is removed; f. After cleaning, pour the diamond into a beaker containing water and bake it until the acid from the acid washing is removed. Step 10: After acid washing, weigh the output, screen the particles using a sieve machine, and determine the ash content using a muffle furnace. The sintering temperature is 980℃, and the time is not less than 6 hours. The principle of sintering diamond and detecting its ash content using a muffle furnace (box-type resistance furnace) is mainly based on high-temperature oxidation. By burning the carbon (C) component in the diamond, the remaining inorganic matter is the ash. The following are the detailed principles, steps, and precautions: 1. Detection principle: High-temperature oxidation of diamond (carbon): Diamond will be completely oxidized into CO2 gas and volatilized under high temperature (usually 600–1000℃) and aerobic conditions. The reaction formula is: C (diamond) + O2 → CO2↑. Ash residue: Non-carbon components in diamond (such as metal catalysts, mineral inclusions, surface adsorbates, etc.) cannot be oxidized and volatilized, and are ultimately retained in the form of solid residue (ash). The ash content is calculated by weighing. 2. Experimental steps: (1) Sample preparation (sample form): diamond powder, granules or broken synthetic diamond blocks. Pretreatment: clean surface contaminants with organic solvents (such as acetone, alcohol). After drying, weigh accurately (record as m1, accuracy must be 0.1 mg). (2) Muffle furnace sintering temperature setting: select 980℃ (to ensure complete oxidation of diamond and avoid excessive temperature leading to ash melting). Oxidation environment: introduce air or oxygen to accelerate oxidation (if the muffle furnace has no gas interface, the furnace can be opened to utilize natural convection). Time control: maintain high temperature for 2–4 hours until the sample reaches constant weight (no further mass loss). (3) Ash weighing and calculation: Cooling: turn off the muffle furnace and remove the crucible after the temperature drops below 200℃ (to avoid thermal shock breakage). Weighing: weigh the residue mass with a precision balance (record as m2).

[0113] Ash content calculation: Ash content (%) = .

[0114] The test data obtained under pressures of 40-50.5-61.5 MPa are shown in Tables 4 and 5 below:

[0115] Table 4

[0116]

[0117] Ash content 1.88%

[0118] Table 5

[0119]

[0120] Ash content 1.56%

[0121] The yield, particle size, and ash content of both normal and recycled nickel are within the acceptable range for diamond production, with minimal differences. Therefore, the method of using recycled nickel to produce diamonds is feasible. Visually, diamonds made from normal and recycled nickel appear similar. Figure 5 , Figure 6 , Figure 7 Normal nickel diamond observed under a microscope Figure 8 Observe the recovery of nickel as Figure 9 .

[0122] Example 2

[0123] A method for recovering nickel and verifying whether recovered nickel can be used to prepare diamond includes the following steps: Step 1: Extracting waste nickel from the treated electrolyte after diamond production and reprocessing it into a catalyst: ① Pre-treatment: a1, demolding the recovered electrolytic waste nickel plate; b1, pre-treating the recovered nickel (Ni) by baking it at a high temperature above 180℃ for 3 hours in a high-temperature oven. ② High-temperature purification: a2, alloying the pre-treated and baked recovered nickel plate at a high temperature of 1400-1600℃ for 20 minutes using a medium-frequency furnace; b2, cooling the high-temperature alloyed molten iron to below 100℃ for 24 hours. ③ Nickel (Ni) content analysis and cutting: a3, performing spectral analysis on the demolded rods using a spectrometer to determine the distribution and proportion of iron-nickel (Ni) content to calculate the formula based on the nickel content proportion; b3, cutting and storing the rods using gantry shears. ④ Formula calculation: a4, calculating the formula based on the recovered nickel proportion and weighing the formula. ⑤ Alloy smelting and water atomization treatment: a5, use a medium frequency furnace and a high pressure pump to smelt and alloy the prepared raw materials; b5, atomize them into powder; c5, bake and sieve.

[0124] The intermediate frequency furnace and its subsequent steps are as follows: A. Operation of the intermediate frequency furnace: (1) Turn on the circulating water and check whether each drain outlet is draining normally. (2) Clean the debris inside the furnace. (3) Check whether the intermediate frequency furnace switches are all in the closed state and whether the frequency knob is in the zero position. (4) Turn on the power supply, turn the switch pause knob to pause, and press the main power switch button. At this time, you will hear a click, and the power switch is successfully closed. (5) Rotate the switch pause knob to open. Slowly rotate the frequency knob until it reaches the maximum. (6) Check whether the high pressure pump water circuit switch is open and whether the drainage is smooth. (7) Turn on the nitrogen flow meter in the atomizing tank to 6m³. (8) Rotate the furnace opening at an angle to put in the iron rod to be fired and the remaining material, and cover it with a glass fiber pad. (9) Since the furnace opening diameter is small and the material can be put in a limited way, continue to add material to melt after melting. (10) When adding material in the middle, tilt the furnace opening slightly and wear fireproof equipment. (11) When the ammeter of the intermediate frequency furnace slowly drops, it means that the iron rod has turned red-hot and has melted when it slowly rises. (12) Wear protective gear and continuously check the changes in the molten iron and the combustion temperature through the goggles. (13) Place the baked molten iron pot at the atomizing charging port and prepare to pour the material. (14) When the molten iron turns light yellow and there are no snowflakes floating on it, it is ready to be poured into the furnace. (15) Before pouring the material, turn on the high-pressure pump and check whether the pressure gauge of the high-pressure pump is within the range. (16) Pour the material at a uniform and slow speed during the pouring process. Do not speed up or stop suddenly to prevent damage to the outside. (17) After pouring the material, the molten iron pot should be repaired, slag removed, and the leak replaced before it can be used again.

[0125] B. Receiving worker's operation: (1) When the atomizing tank is filled with water, turn on the water pump and observe the water level rise. Stop the water pump when the water level reaches the mark. (2) When the high-pressure pump starts, the material pouring begins. Check the pressure of the high-pressure pump regularly to see if it is within the allowable range. (3) When the high-pressure pump is turned off, the material pouring ends. The receiving worker starts to release the material. If the material cannot be released, shake the water pipe up and down. (4) Put the released water into the collection tank for sedimentation and adsorption. Wait for five minutes and observe the clarity of the water. Release the water when it reaches the release standard. Continue to refill the atomizing tank with water during the process. (5) After the water is released, carry out the material collection process. Use a shovel to collect the material into the tray.

[0126] C. Vacuum Oven Operation: (1) Clean the debris inside the furnace. (2) Turn on the oven and set the temperature to 175℃. (3) Measure the temperature inside the furnace; the keypad will display the temperature inside the furnace. (4) Arrange the material collected in the tray neatly inside the furnace. Close the furnace door and check if the oven vent valve is closed. (5) Open the vacuum pump pipeline valve before the oven. Open the circulating water valve and set the water ring pump time relay to start vacuuming. (6) Observe whether the pointer of the vacuum pressure gauge moves. (7) Set the time relay time according to the thickness and humidity of the raw material. Continue until the raw material is dry (it must be consistent with the water ring pump time setting).

[0127] Step D, Step Two: After completing the nickel recycling process, mix the graphite and masterbatch (dried in a high-temperature oven) with the catalyst in a specific ratio. Dry the graphite and masterbatch in a high-temperature oven at 180℃ for at least 6 hours. The mass mixing ratio of graphite, masterbatch, and catalyst is m(graphite + masterbatch):mcatalyst = 4:6. Use the same graphite and masterbatch, but use a different catalyst (one normal and one recycled nickel). After mixing, add both materials to two multi-dimensional mixers and run them for 6-8 hours (the mixing time is the same for both mixers). Step Three: Granulate the mixed materials. Add the mixed materials to a granulator for two passes of granulation, achieving a particle size of 3-4 mm. Step Four: Perform initial pressing of the granulated materials to form graphite cores. The cores should be 42.5 × 35 mm in size, weighing 149-149.2 g, with a diameter of approximately 41.4 mm. Step 5: After pressing, place the material in a vacuum furnace for sintering. Step 6: After sintering, perform a second pressing, controlling the pressure at 14-15 MPa. The weight of the second pressing is 148.2-148.3 g, the diameter is 42.4-42.5 mm, and the height is 34.9 ± 0.1 mm. Step 7: Press the 3-4 mm second-stage granules after mixing and granulation, and assemble the fired core column with pyrophyllite and other accessories. Step 8: Conduct a machine test on the assembled block, with a pressure of 41-50.5-62 MPa and constant power. Step Nine: After completing the diamond synthesis, perform acid washing: a. Crush the synthesized core using a four-column press; b. Pour the crushed material into a 5L glass beaker, add concentrated sulfuric acid and concentrated hydrochloric acid (volume ratio approximately 1:1), ensuring the sulfuric acid and hydrochloric acid completely cover the crushed material in the beaker; c. Heat the beaker in a furnace until the yellow smoke gradually turns into white smoke, then remove it from the furnace and cool; d. Once the material in the beaker from step c has cooled to room temperature, wash it and add aqua regia (concentrated hydrochloric acid: concentrated nitric acid volume ratio = 3:1), repeating step c; e. After step d is completed, repeat steps c and d until the graphite and catalyst coating the diamond is removed; f. After cleaning, pour the diamond into a beaker containing water and bake it until the acid from the acid washing is removed. After acid washing, weigh the yield, sieve the particles using a sieve machine, and determine the ash content using a muffle furnace.

[0128] The test data obtained under pressures of 41-50.5-62 MPa are shown in Tables 6 and 7 below:

[0129] Table 6

[0130]

[0131] Ash content: 2.01%

[0132] Table 7

[0133]

[0134] Ash content: 1.93%

[0135] The yield, particle size, and ash content of both normal nickel and recycled nickel are within the range of diamond specifications, and the differences are not significant. Therefore, the method of using recycled nickel to make diamonds is feasible.

[0136] Example 3

[0137] A method for recovering nickel and verifying whether recovered nickel can be used to prepare diamond includes the following steps: Step 1: Extracting waste nickel from the treated electrolyte after diamond production and reprocessing it into a catalyst: ① Pre-treatment: a1, demolding the recovered electrolytic waste nickel plate; b1, pre-treating the recovered nickel (Ni) by baking it at a high temperature above 180℃ for 3 hours in a high-temperature oven. ② High-temperature purification: a2, alloying the pre-treated and baked recovered nickel plate at a high temperature of 1400-1600℃ for 20 minutes using a medium-frequency furnace; b2, cooling the high-temperature alloyed molten iron to below 100℃ for 24 hours. ③ Nickel (Ni) content analysis and cutting: a3, performing spectral analysis on the demolded rods using a spectrometer to determine the distribution and proportion of iron-nickel (Ni) content to calculate the formula based on the nickel content proportion; b3, cutting and storing the rods using gantry shears. ④ Formula calculation: a4, calculating the formula based on the recovered nickel proportion and weighing the formula. ⑤ Alloy smelting and water atomization treatment: a5, use a medium frequency furnace and a high pressure pump to smelt and alloy the prepared raw materials; b5, atomize them into powder; c5, bake and sieve.

[0138] The intermediate frequency furnace and its subsequent steps are as follows: A. Operation of the intermediate frequency furnace: (1) Turn on the circulating water and check whether each drain outlet is draining normally. (2) Clean the debris inside the furnace. (3) Check whether the intermediate frequency furnace switches are all in the closed state and whether the frequency knob is in the zero position. (4) Turn on the power supply, turn the switch pause knob to pause, and press the main power switch button. At this time, you will hear a click, and the power switch is successfully closed. (5) Rotate the switch pause knob to open. Slowly rotate the frequency knob until it reaches the maximum. (6) Check whether the high pressure pump water circuit switch is open and whether the drainage is smooth. (7) Turn on the nitrogen flow meter in the atomizing tank to 6m³. (8) Rotate the furnace opening at an angle to put in the iron rod to be fired and the remaining material, and cover it with a glass fiber pad. (9) Since the furnace opening diameter is small and the material can be put in a limited way, continue to add material to melt after melting. (10) When adding material in the middle, tilt the furnace opening slightly and wear fireproof equipment. (11) When the ammeter of the intermediate frequency furnace slowly drops, it means that the iron rod has turned red-hot and has melted when it slowly rises. (12) Wear protective gear and continuously check the changes in the molten iron and the combustion temperature through the goggles. (13) Place the baked molten iron pot at the atomizing charging port and prepare to pour the material. (14) When the molten iron turns light yellow and there are no snowflakes floating on it, it is ready to be poured into the furnace. (15) Before pouring the material, turn on the high-pressure pump and check whether the pressure gauge of the high-pressure pump is within the range. (16) Pour the material at a uniform and slow speed during the pouring process. Do not speed up or stop suddenly to prevent damage to the outside. (17) After pouring the material, the molten iron pot should be repaired, slag removed, and the leak replaced before it can be used again.

[0139] B. Receiving worker's operation: (1) When the atomizing tank is filled with water, turn on the water pump and observe the water level rise. Stop the water pump when the water level reaches the mark. (2) When the high-pressure pump starts, the material pouring begins. Check the pressure of the high-pressure pump regularly to see if it is within the allowable range. (3) When the high-pressure pump is turned off, the material pouring ends. The receiving worker starts to release the material. If the material cannot be released, shake the water pipe up and down. (4) Put the released water into the collection tank for sedimentation and adsorption. Wait for five minutes and observe the clarity of the water. Release the water when it reaches the release standard. Continue to refill the atomizing tank with water during the process. (5) After the water is released, carry out the material collection process. Use a shovel to collect the material into the tray.

[0140] C. Vacuum Oven Operation: (1) Clean the debris inside the furnace. (2) Turn on the oven and set the temperature to 175℃. (3) Measure the temperature inside the furnace; the keypad will display the temperature inside the furnace. (4) Arrange the material collected in the tray neatly inside the furnace. Close the furnace door and check if the oven vent valve is closed. (5) Open the vacuum pump pipeline valve before the oven. Open the circulating water valve and set the water ring pump time relay to start vacuuming. (6) Observe whether the pointer of the vacuum pressure gauge moves. (7) Set the time relay time according to the thickness and humidity of the raw material. Continue until the raw material is dry (it must be consistent with the water ring pump time setting).

[0141] Step D, Step Two: After completing the nickel recycling process, mix the graphite and masterbatch (dried in a high-temperature oven) with the catalyst in a specific ratio. Dry the graphite and masterbatch in a high-temperature oven at 180℃ for at least 6 hours. The mass mixing ratio of graphite, masterbatch, and catalyst is m(graphite + masterbatch):mcatalyst = 4:6. Use the same graphite and masterbatch, but use a different catalyst (one normal and one recycled nickel). After mixing, add both materials to two multi-dimensional mixers and run them for 6-8 hours (the mixing time is the same for both mixers). Step Three: Granulate the mixed materials. Add the mixed materials to a granulator for two passes of granulation, achieving a particle size of 3-4 mm. Step Four: Perform initial pressing of the granulated materials to form graphite cores. The cores should be 42.5 × 35 mm in size, weighing 149-149.2 g, with a diameter of approximately 41.4 mm. Step 5: After pressing, place the material in a vacuum furnace for sintering. Step 6: After sintering, perform a second pressing, controlling the pressure at 14-15 MPa. The weight of the second pressing is 148.2-148.3 g, the diameter is 42.4-42.5 mm, and the height is 34.9 ± 0.1 mm. Step 7: Press the 3-4 mm second-stage granules after mixing and granulation, and assemble the fired core with pyrophyllite and other accessories. Step 8: Conduct a machine test on the assembled block, with a pressure of 40-50-61 MPa and constant power. Step 9: After completing the diamond synthesis, perform acid washing: a. Crush the synthesized core using a four-column press; b. Pour the crushed material into a 5L glass beaker, add concentrated sulfuric acid and concentrated hydrochloric acid (volume ratio approximately 1:1), ensuring the concentrated sulfuric acid and hydrochloric acid completely cover the crushed material in the beaker; c. Heat the beaker in a furnace until the yellow smoke gradually turns into white smoke, then remove it from the furnace and cool it; d. After the material in the beaker from step c has cooled to room temperature, wash it and add aqua regia (concentrated hydrochloric acid: concentrated nitric acid volume ratio = 3:1), repeating step c; e. After step d is completed, repeat steps c and d until the graphite and catalyst coating the diamond is removed; f. After cleaning, pour the diamond into a beaker containing water and bake it until the acid from the acid washing is removed. Step 10: After pickling is completed, weigh the output, use a screening machine to screen the particle size, and use a muffle furnace to determine the ash content.

[0142] The test data obtained under pressures of 40-50-61 MPa are shown in Tables 8 and 9 below:

[0143] Table 8

[0144]

[0145] Ash content: 1.03%

[0146] Table 9

[0147]

[0148] Ash content: 1.32%

[0149] The yield, particle size, and ash content of both normal nickel and recycled nickel are within the range of diamond specifications, and the differences are not significant. Therefore, the method of using recycled nickel to make diamonds is feasible.

[0150] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method of recovering nickel and verifying whether the recovered nickel can produce diamond, characterized by, The method comprises the following steps: Step 1: extracting waste nickel from the used diamond-making electrolyte, and making the catalyst again; Step 2: mixing the high-temperature oven-dried graphite and the mother powder with the catalyst according to the proportion; Step 3: granulating the mixed material; Step 4: primary pressing the granulated material to form a graphite core column; Step 5: placing the primary pressed graphite core column into a vacuum furnace for baking; Step 6: secondary pressing the baked core column; Step 7: assembling the core column with talc-related accessories after mixing, granulating, pressing and baking; Step 8: performing machine test on the assembled block; Step 9: acid washing the core column after the machine test to obtain the synthesized diamond data; Step 10: comparing the data of the diamond made of recycled nickel with the data of the diamond made of normal nickel under the same pressure and power to verify whether the recycled nickel is suitable for making diamond.

2. The method of claim 1, wherein the recovered nickel is verified to be capable of producing diamond. The process of recycling waste nickel in step 1 is: early pretreatment, high-temperature purification, analysis of nickel content, calculation of proportioning, alloy smelting and water atomization treatment.

3. The method of claim 2, wherein the recovered nickel is used to produce diamond. 3 The high-temperature purification is performed by using a medium-frequency furnace, and the purification temperature is 1400-1600 DEG C.

4. The method of claim 2, wherein the recovered nickel is verified to be capable of producing diamond. The alloy smelting and water atomization treatment are performed by using a medium-frequency furnace and a high-pressure pump.

5. The method of claim 1, wherein the recovered nickel is verified to be capable of producing diamond. In step 2, the mass mixing proportion of graphite, mother powder and catalyst is graphite + mother powder: catalyst = 4:6, and the temperature for drying the graphite and mother powder by using a high-temperature oven is greater than or equal to 180 DEG C, and the time is greater than or equal to 6 hours.

6. The method of claim 1, wherein the recovered nickel is verified to be capable of producing diamond. In step 5, the method for placing the pressed graphite core column into a vacuum furnace for baking is as follows: a. heating to 400 DEG C for 30 minutes and keeping for 15 minutes; b. heating to 900 DEG C for 180 minutes and keeping for 15 minutes; c. heating to 1100 DEG C for 120 minutes and keeping for 720 minutes; d. after heating is completed, the temperature naturally decreases to 900 DEG C, nitrogen is filled, and the fan is started, and the fan is started after the nitrogen is supplemented.

7. The method of claim 1, wherein the recovered nickel is verified to be capable of producing diamond. In step 6, the pressing weight of the secondary pressed core column is 148.2-148.3 g, the diameter is 42.4-42.5 mm, and the height is 34.9±0.1 mm.

8. The method of claim 1, wherein the recovered nickel is verified to be capable of producing diamond. In step 7, the talc needs to be oven-dried for early treatment, and the treatment method comprises the following steps: a. heating from room temperature to 150 DEG C for 90 minutes and keeping for 240 minutes; b. heating from 150 DEG C to 200 DEG C for 90 minutes and keeping for 240 minutes; c. heating from 200 DEG C to 250 DEG C for 90 minutes and keeping for 240 minutes; d. heating from 250 DEG C to 280 DEG C for 90 minutes and keeping for 240 minutes; e. naturally cooling from 280 DEG C to 60 DEG C and keeping for 240 minutes.

9. The method of claim 1, wherein the recycled nickel is produced by a method comprising: In step 9, the specific operation method of acid washing comprises the following steps: ​ a. crushing the synthesized core column by using a four-column press; b. pouring the crushed material into a glass beaker, adding concentrated sulfuric acid and concentrated hydrochloric acid, and the volume ratio of concentrated sulfuric acid to concentrated hydrochloric acid is 1:1; c. placing the beaker on a heating furnace for heating until the yellow smoke emitted slowly becomes white smoke, and then taking the beaker off the heating furnace for cooling; d. After the material in the beaker of step c is cooled to room temperature, it is washed and added to aqua regia, and step c is repeated; e. After step d is completed, steps c and d are repeated until the graphite that surrounds the diamond and the catalyst are removed; f. After being washed clean, the diamond is poured into a beaker with water and baked until the acid in the pickling is removed.

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