Method for recovering Ru or Ir in waste material

Abstract

The invention discloses a method for recovering Ru or Ir in waste materials, which comprises the following steps: 1) sequentially carrying out sand blasting, crushing, acid pickling, cleaning and drying on waste raw materials to obtain raw materials; wherein the waste raw materials are used residual targets and / or refractory oxide crystal growth vessel waste materials; 2) adding the raw materials into a crucible and placing the crucible in a magnetic suspension smelting furnace; preheating a mold, and placing the mold under the crucible; after vacuumizing, inert atmosphere and hydrogen are introduced, magnetic levitation smelting is started, after the temperature is increased to the smelting temperature, heat preservation is conducted, and molten metal is obtained; and then under the condition that magnetic levitation is not closed, molten metal is poured into the mold, after pouring is completed, the magnetic levitation is closed, a vibrator below the mold is started to vibrate the mold, after the vibrator is closed, the molten metal is condensed, and the recycled ruthenium ingot or iridium ingot is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of precious metal recycling, and particularly relates to a method for recycling Ru or Ir from waste materials. Background Art

[0002] Ru and Ir metals have characteristics such as high melting point, high strength, corrosion resistance, and wear resistance, which have enabled their wide application in fields such as electronics, aerospace, medical treatment, and chemical reactors. However, Ru and Ir belong to scarce precious metal resources, with a content of only one in a billion in the earth's crust. Moreover, the melting points of Ru and Ir metals are both at 2300 °C, and it is difficult to recycle and utilize them again.

[0003] Currently, the used Ru or Ir residual targets and refractory oxide crystal growth vessel waste materials (the material of the vessels is Ru or Ir) are mainly recycled by smelting methods, and the main methods are high-frequency induction smelting method and electron beam smelting method. Among them, although the high-frequency induction smelting method can achieve rapid melting of ruthenium and iridium metals, due to its non-contact heating characteristics, it is difficult to precisely control the local temperature, which may cause incomplete melting of ruthenium or iridium in some areas or incomplete removal of impurities; thus, the purity of ruthenium or iridium products obtained by the high-frequency induction smelting method is insufficient. The temperature gradient on the surface of the molten pool is relatively large during the electron beam smelting process, which affects the uniformity of the product; moreover, the secondary electrons and backscattered electrons generated during the electron beam smelting process are likely to introduce trace amounts of impurity elements, reducing the purity of ruthenium or iridium products. In summary, based on the current smelting recycling methods, high-purity ruthenium or iridium products cannot be obtained, so it is very necessary to develop a new method for recycling Ru or Ir from waste materials. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide a method for recycling Ru or Ir from waste materials.

[0005] The present invention provides a method for recycling Ru or Ir from waste materials, including the following steps: (1) Sandblasting, crushing, pickling, cleaning, and drying the waste raw materials in sequence to obtain raw materials; wherein, the waste raw materials are used residual targets and / or refractory oxide crystal growth vessel waste materials; (2) Adding the raw materials into a crucible and placing it in a magnetic levitation smelting furnace; preheating the mold and placing it directly below the crucible; after evacuating, introducing an inert atmosphere and hydrogen, starting magnetic levitation smelting, heating up to the smelting temperature, and holding for heat preservation to obtain a metal liquid; then, without turning off the magnetic levitation, pouring the metal liquid into the mold, after pouring, turning off the magnetic levitation, starting the vibrator below the mold to vibrate the mold, and after turning off the vibrator, allowing the metal liquid to condense to obtain the recycled ruthenium ingot or iridium ingot.

[0006] Preferably, in the step (1), it is broken into pieces with a size of ≤ 100 mm, and more preferably 50 - 100 mm.

[0007] Preferably, in the step (1), the pickling solution used for pickling is composed of a nitric acid solution and a hydrochloric acid solution with a volume ratio of 1:(2 - 4); the concentration of the nitric acid solution is 20 - 30 wt%, and the concentration of the hydrochloric acid solution is 15 - 20 wt%.

[0008] Preferably, in the step (1), the temperature of the pickling is 100 - 120 °C, and the pickling time is 1.5 - 4 h.

[0009] More preferably, the pickling is first stirred and pickled for 1 - 3 h, and then pickled for 0.5 - 1 h without stirring.

[0010] Preferably, in the step (1), the cleaning is performed by ultrasonic cleaning with pure water; wherein: the number of ultrasonic cleaning times is 2 - 4 times, the ultrasonic cleaning time for each time is 20 - 30 min, the ultrasonic cleaning power is 30 - 50 kHz, and the ultrasonic cleaning temperature is 40 - 50 °C.

[0011] Preferably, in the step (1), the drying is performed by vacuum drying; the vacuum drying temperature is 120 - 130 °C, and the vacuum drying time is 2 - 3 h.

[0012] Preferably, in the step (2), during the process of adding the raw materials to the crucible, the small pieces of raw materials are placed at the bottom layer, and the large pieces of raw materials are placed at the upper layer.

[0013] Preferably, in the step (2), the preheating temperature of the mold is 500 - 600 °C.

[0014] Preferably, in the step (2), the feeding rate of hydrogen is 50 - 150 mL / min.

[0015] Preferably, in the step (2), the melting temperature is 2380 - 2500 °C, and the holding time is 3 - 5 min.

[0016] Preferably, in the step (2), the time for vibrating the mold is 10 - 15 min.

[0017] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: (1) In the recovery method of the present invention, the electromagnetic levitation melting method is adopted. Electromagnetic levitation melting can reduce the contact between the molten metal and the crucible, thereby avoiding the entry of crucible element impurities into the molten metal at high temperature, which affects the purity of the recovered iridium ingot or ruthenium ingot; moreover, in the pouring process of the present invention, the electromagnetic levitation is not turned off, which can basically ensure that the crucible impurities do not enter the metal ingot, further ensuring the purity of the iridium ingot or ruthenium ingot.

[0018] (2) In the recovery method of the present invention, hydrogen is introduced during the magnetic levitation melting process. Under the protection of hydrogen, oxidation during the high-temperature melting of ruthenium or iridium can be avoided, and part of the oxidized ruthenium or iridium can be reduced under high-temperature hydrogen protection (at a temperature of 1000 °C and above), thereby improving the purity and recovery rate of ruthenium ingots or iridium ingots.

[0019] (3) In the recovery method of the present invention, the mold is preheated to avoid excessive temperature difference between the mold and the molten metal during pouring, which may cause the mold to crack, resulting in pollution and loss of the molten metal.

[0020] (4) In the recovery method of the present invention, vibration is carried out after pouring. Vibration effectively reduces the internal pores of the ingot, making the material utilization rate higher and improving the production quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a process flow chart of the present invention.

[0022] Figure 2 It is a heating program chart in Example 1.

[0023] Figure 3 It is a physical picture of the Ir ingot prepared in Example 1.

[0024] Figure 4 It is a physical picture of the Ir ingot prepared in Comparative Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0025] As described above, the present invention provides a method for recovering Ru or Ir from waste materials, including the following steps: (1) After the waste raw materials are successively subjected to sandblasting, crushing, pickling, cleaning and drying, raw materials are obtained; wherein, the waste raw materials are used residual targets and / or waste refractory oxide crystal growth vessels; (2) Add the raw materials into a crucible and place it in a magnetic levitation melting furnace; after preheating the mold, place it directly below the crucible; after evacuating, introduce an inert atmosphere and hydrogen, start magnetic levitation melting, heat up to the melting temperature, keep warm, and obtain molten metal; then, without closing the magnetic levitation, pour the molten metal into the mold. After pouring, close the magnetic levitation, start the vibrator below the mold to vibrate the mold, and after closing the vibrator, let the molten metal condense to obtain the recovered ruthenium ingot or iridium ingot.

[0026] In the present invention, the magnetic levitation melting method is used to recover ruthenium or iridium from waste raw materials, which can enable Ru or Ir to reach melting quickly, not only reducing metal loss, but also effectively improving processing efficiency.

[0027] In the present invention, a maglev melting method is adopted to recover ruthenium or iridium from waste raw materials. During the maglev melting process, the molten metal does not come into contact with the crucible, and the pouring process is also carried out without turning off the maglev. Therefore, the molten metal hardly contacts the crucible. Thus, under high-temperature conditions, the impurities in the crucible do not enter the molten metal, which can improve the purity of the recovered ruthenium ingot or iridium ingot.

[0028] Since the melting temperature of ruthenium or iridium is relatively high, in the recovery method of the present invention, after preheating the mold, the large temperature difference between the molten metal and the mold can be avoided, which may cause cracking of the mold, resulting in a decrease in the purity of the molten metal or leakage, and reducing the loss rate of ruthenium or iridium.

[0029] In the recovery method of the present invention, the molten metal is vibrated after pouring, which can reduce the pores in the ingot and improve the quality of the ruthenium ingot or iridium ingot.

[0030] The main components Ru or Ir in the waste raw materials also contain one or more of impurities such as oxides of Fe, Al, Cu, and In.

[0031] Preferably, in the step (1), it is broken into fragments with a size of ≤100 mm, more preferably 50 - 100 mm, including but not limited to 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc.

[0032] In the present invention, controlling the size of the broken fragments can reduce the loss rate of ruthenium or iridium. If the fragment size is too large, the maglev melting time will increase, the cost will increase, the loss rate will also increase, and uneven melting may occur. If the fragment size is too small, there will be splashing of small fragments during maglev melting, resulting in raw material loss.

[0033] Preferably, in the step (1), the pickling acid solution used consists of a nitric acid solution and a hydrochloric acid solution with a volume ratio of 1:(2 - 4); the concentration of the nitric acid solution is 20 - 30 wt%, and the concentration of the hydrochloric acid solution is 15 - 20 wt%.

[0034] In the present invention, ruthenium or iridium metal is relatively stable in an acidic solution. By pickling, the acid-soluble impurities in the waste raw materials can be well removed, thereby improving the purity of the recovered product.

[0035] Preferably, in the step (1), the pickling temperature is 100 - 120 °C, including but not limited to 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, etc.; the pickling time is 1.5 - 4 h, including but not limited to 1.5 h, 2.0 h, 2.5 h, 3.0 h, 3.5 h, 4.0 h, etc.

[0036] Further preferably, for the pickling, first stir and pickle for 1 - 3 h, and then pickle for 0.5 - 1 h without stirring.

[0037] Preferably, in the step (1), ultrasonic cleaning is carried out using pure water; wherein: the number of ultrasonic cleaning times is 2 - 4 times, including but not limited to 2 times, 3 times or 4 times; The ultrasonic cleaning time for each time is 20 - 30 min, including but not limited to 20 min, 22 min, 25 min, 28 min, 30 min, etc.; The ultrasonic cleaning power is 30 - 50 kHz, including but not limited to 30 kHz, 35 kHz, 40 kHz, 45 kHz, 50 kHz, etc.; The ultrasonic cleaning temperature is 40 - 50 °C, including but not limited to 40 °C, 42 °C, 45 °C, 48 °C, 50 °C, etc.

[0038] In the present invention, ultrasonic cleaning is carried out after pickling, which can play a role in cleaning, reduce adhesive impurities, and improve the purity of the recovered iridium ingot or ruthenium ingot.

[0039] Preferably, in the step (1), vacuum drying is adopted; the vacuum drying temperature is 120 - 130 °C, including but not limited to 120 °C, 122 °C, 125 °C, 128 °C, 130 °C, etc.; the vacuum drying time is 2 - 3 h, including but not limited to 2.0 h, 2.2 h, 2.5 h, 2.8 h, 3.0 h, etc.

[0040] Preferably, in the step (2), during the process of adding raw materials to the crucible, small pieces of raw materials are placed at the bottom layer, and large pieces of raw materials are placed at the upper layer.

[0041] In the present invention, placing small pieces of raw materials at the bottom layer and large pieces of raw materials at the upper layer can greatly reduce the splashing of small pieces of materials during magnetic levitation melting and reduce the loss rate of Ru or Ir.

[0042] Preferably, in the step (2), the preheating temperature of the mold is 500 - 600 °C, including but not limited to 500 °C, 520 °C, 540 °C, 550 °C, 560 °C, 580 °C, 600 °C, etc.

[0043] Preferably, in the step (2), the feeding rate of hydrogen is 50 - 150 mL / min, including but not limited to 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min, 100 mL / min, 110 mL / min, 120 mL / min, 130 mL / min, 140 mL / min, 150 mL / min, etc.

[0044] Preferably, in the step (2), the melting temperature is 2380~2500°C, including but not limited to 2380°C, 2400°C, 2420°C, 2440°C, 2450°C, 2460°C, 2480°C, 2500°C, etc.; the heat preservation time is 3~5 min, including but not limited to 3.0 min, 3.5 min, 4.0 min, 4.5 min, 5.0 min, etc.

[0045] Preferably, in the step (2), the vibration time of the mold is 10~15 min, including but not limited to 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.

[0046] To facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings of the specification and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0047] The process flow chart of the method for recovering Ru or Ir from waste materials in the present invention is as Figure 1 shown, and the specific method can be seen in the embodiments.

[0048] Example 1 1) The refractory oxide crystal growth vessel waste iridium metal material is subjected to sandblasting treatment using a sandblaster to remove the adhesives on the surface of the iridium metal waste material; when sandblasting, 120# sand is used, the sandblasting air pressure is 5-6 Pa, rotary sandblasting is adopted, and the sandblasting time is 5 min; after sandblasting, it is necessary to observe whether there are still adhesives that have not been cleaned up. If there are adhesives that have not been cleaned up, the local position is sandblasted again according to the above process; finally, the sandblasted iridium metal waste material is obtained.

[0049] 2) The sandblasted iridium metal waste material is put into a crusher for crushing, and the fragment size is controlled to be between 50 and 100 mm during crushing to obtain crushed material.

[0050] 3) The crushed material is placed in an acid pickling tank, and a mixed acid solution composed of hydrochloric acid and nitric acid (where the volume ratio of hydrochloric acid to nitric acid in the mixed acid is 3:1; the concentration of hydrochloric acid is 15 wt%; the concentration of concentrated nitric acid is 30 wt%) is slowly poured until the mixed acid solution completely submerges the crushed material, then it is heated to 110°C, and stirred at this temperature for 2 h, then the stirring is stopped, and it is continuously boiled at this temperature for 45 min. After stopping heating, the acid is drained and the crushed material is taken out to obtain the pickled crushed material.

[0051] 4) Place the pickled crushed material in an ultrasonic cleaning tank and perform ultrasonic cleaning three times with pure water. Among them: the temperature of ultrasonic cleaning is 45°C, the frequency of ultrasonic cleaning is 40 kHz, and the time for each ultrasonic cleaning is 25 min. After ultrasonic cleaning, take out the crushed material and let it dry. Then vacuum dry it at 120°C for 2.5 h to obtain the Ir raw material.

[0052] 5) Preheat the mold in a heating furnace for 1.5 - 2 h to make the mold temperature reach 600°C. Add 15 kg of Ir raw material into a D120 mm water-cooled copper crucible. When feeding, place small pieces of material at the bottom of the crucible and cover the small pieces with large pieces of material to reduce the splashing of the material out of the crucible. Then place the water-cooled crucible in a magnetic levitation melting furnace. Take out the mold with a temperature of 600°C from the heating furnace and place it on the vibrating plate under the water-cooled crucible to fix it. After closing the furnace door, use a vacuum pump to evacuate, and then introduce nitrogen to clean the furnace chamber. Repeat the operations of evacuation and nitrogen introduction 2 - 3 times to ensure the purity of the furnace atmosphere. Then introduce hydrogen into the furnace at a rate of 100 mL / min. Turn on the heating device of the magnetic levitation melting furnace and control the heating program of the magnetic levitation melting furnace (the heating program process can be seen Figure 2 ), heat up to 2450 - 2500°C in 8 - 9 min, and the raw material is completely melted into a metal liquid (the metal liquid will be suspended in the center of the crucible). Keep it at this temperature for 4 min, and then turn the handle to pour the metal liquid into the funnel of the mold. After pouring, turn off the heating device, turn on the vibrator under the mold to vibrate for 13 min, then turn off the vibrator and let the metal liquid slowly condense to obtain an Ir ingot.

[0053] In this embodiment, through the magnetic levitation melting process, the entire melting process only takes 12 - 14 min. The obtained Ir ingot has no oxide layer on the surface and no pores inside (specifically visible Figure 3 ). Through GDMS inspection, no new impurities are introduced into the Ir ingot, the oxygen content can be controlled within 30 ppm, and the purity reaches 99.99%. The overall Ir metal loss rate during the melting process is 0.95%.

[0054] Comparative Example 1 It is basically the same as Example 1, the difference is that: in step 5), after the magnetic levitation melting and holding is completed, turn off the heating device and then perform pouring.

[0055] The obtained Ir ingot in this comparative example has no oxide layer on the surface and no pores inside. Through GDMS inspection, trace amounts of copper impurities are detected inside the Ir ingot (the copper comes from the copper element in the water-cooled crucible); the oxygen content can be controlled within 30 ppm, and the purity reaches 99.9%; the overall Ir metal loss rate during the melting process is 0.96%.

[0056] Comparative Example 2 Basically the same as Example 1, with the difference that in step 5), the preheating temperature of the mold is 200 °C.

[0057] In this comparative example, the surface of the Ir ingot has no oxide layer and there are a small number of pores inside. Through GDMS inspection, no new impurities are introduced into the ingot, and the oxygen content can be controlled within 30 ppm. However, when the molten solution is injected into the mold, due to excessive temperature deviation, cracks are generated in the mold, and there is an obvious phenomenon of cracking and leakage of the Ir metal liquid when vibration is turned on, resulting in the leakage of the Ir material being contaminated, and the loss rate of the Ir metal is 23.14%.

[0058] Comparative Example 3 Basically the same as Example 1, with the difference that in step 5), after pouring, no vibration treatment is carried out.

[0059] The surface of the Ir ingot prepared in this comparative example has no oxide layer and a large number of pores are formed inside (visible Figure 4 ), through GDMS inspection, no new impurities are introduced into the ingot, and the oxygen content can be controlled within 30 ppm. The metal loss rate during the melting process is 0.96%.

[0060] Example 2 1) Use a sandblaster to sandblast the ruthenium residue target metal waste used in semiconductor manufacturing sputtering to remove the adhesives on the surface of the ruthenium metal waste; when sandblasting, use sand with a size of 120#, the sandblasting air pressure is 5 - 6 Pa, the sandblasting adopts rotary sandblasting, and the sandblasting time is 5 min; after sandblasting, it is necessary to observe whether there are still adhesives that are not cleaned up. If there are adhesives that are not cleaned up, then according to the above process, sandblast the local position; finally, obtain the sandblasted iridium metal waste.

[0061] 2) Put the sandblasted ruthenium metal waste into a crusher for crushing, and control the fragment size to be between 50 and 100 mm during crushing to obtain crushed material.

[0062] 3) Place the crushed material in an acid pickling tank, slowly pour in a mixed acid solution composed of hydrochloric acid and nitric acid (where the volume ratio of hydrochloric acid to nitric acid is 2:1; the concentration of hydrochloric acid is 20 wt%; the concentration of concentrated nitric acid is 20 wt%) until the mixed acid solution completely submerges the crushed material, then heat to 120 °C, and stir at this temperature for 1.5 h, then stop stirring, continue to boil statically at this temperature for 1 h, stop heating, drain the acid, and then take out the crushed material to obtain the pickled crushed material.

[0063] 4) Place the pickled crushed material in an ultrasonic cleaning tank and perform ultrasonic cleaning 4 times with pure water. Among them: the temperature of ultrasonic cleaning is 40 °C, the frequency of ultrasonic cleaning is 50 kHz, and the time of each ultrasonic cleaning is 20 min. After ultrasonic cleaning, take out the crushed material and let it dry. Then, vacuum dry it at 130 °C for 3 h to obtain the Ru raw material.

[0064] 5) Preheat the mold in a heating furnace for 1.5 - 2 h to make the mold temperature reach 550 °C. Add 15 kg of Ru raw material into a D120 mm water-cooled copper crucible. When feeding, place small pieces of material at the bottom of the crucible and cover large pieces of material on top of the small pieces to reduce the ejection of materials from the crucible. Then, place the water-cooled crucible in a magnetic levitation melting furnace. Take out the mold with a temperature of 550 °C from the heating furnace and place it on the vibrating plate below the water-cooled crucible for fixation. After closing the furnace door, use a vacuum pump to evacuate the air, and then introduce nitrogen to clean the furnace chamber. Repeat the operations of evacuating the air and introducing nitrogen 2 - 3 times to ensure the purity of the furnace atmosphere. Then, introduce hydrogen into the furnace at a rate of 80 mL / min. Turn on the heating device of the magnetic levitation melting furnace and control the heating program of the magnetic levitation melting furnace to raise the temperature to 2450 - 2500 °C in 8 - 9 min. The raw material is completely melted into a metal liquid (the metal liquid will be suspended in the center of the crucible). Keep it at this temperature for 5 min, then turn the handle to pour the metal liquid into the funnel of the mold. After pouring, turn off the heating device and turn on the vibrator below the mold to vibrate for 15 min, then turn off the vibrator and let the metal liquid slowly solidify to obtain the Ru ingot.

[0065] In this embodiment, through the magnetic levitation melting process, the entire melting process only takes 13 - 15 min. The obtained Ru ingot has no oxide layer on the surface and no pores inside. Through GDMS inspection, no new impurities are introduced into the Ru ingot, the oxygen content can be controlled within 30 ppm, and the purity reaches 99.9995%. The overall Ru metal loss rate during the melting process is 0.95%.

[0066] Example 3 1) Use a sandblaster to sandblast the waste iridium metal material in the refractory oxide crystal growth vessel to remove the adhesives on the surface of the iridium metal waste. When sandblasting, use 120# sand, the sandblasting air pressure is 5 - 6 Pa, and rotary sandblasting is used. The sandblasting time is 6 min. After sandblasting, it is necessary to observe whether there are still adhesives not cleaned up. If there are adhesives not cleaned up, perform sandblasting on the local position according to the above process. Finally, obtain the sandblasted iridium metal waste.

[0067] 2) Put the sandblasted iridium metal waste into a crusher for crushing. When crushing, control the fragment size to be between 50 - 100 mm to obtain the crushed material.

[0068] 3) Place the crushed materials in a pickling tank, and slowly pour in a mixed acid solution composed of hydrochloric acid and nitric acid (where the volume ratio of hydrochloric acid to nitric acid is 4:1; the concentration of hydrochloric acid is 20 wt%; the concentration of concentrated nitric acid is 25 wt%) until the mixed acid solution completely submerges the crushed materials. Then heat to 115 °C and stir at this temperature for 3 h. Then stop stirring and continue to boil quietly at this temperature for 30 min. After stopping heating, drain the acid and take out the crushed materials to obtain the pickled crushed materials.

[0069] 4) Place the pickled crushed materials in an ultrasonic cleaning tank and perform ultrasonic cleaning three times with pure water. Among them: the temperature of ultrasonic cleaning is 50 °C, the frequency of ultrasonic cleaning is 60 kHz, and the time of each ultrasonic cleaning is 30 min. After ultrasonic cleaning, take out the crushed materials and let them dry. Then vacuum dry at 120 °C for 3 h to obtain the Ir raw materials.

[0070] 5) Place the mold in a heating furnace and preheat it for 1.5 - 2 h so that the mold temperature can reach 500 °C. Add 10 kg of Ir raw materials into a water-cooled crucible with a diameter of D120 mm. When feeding, place small pieces of materials at the bottom of the crucible and cover large pieces of materials on top of the small pieces to reduce the splashing of materials out of the crucible. Then place the water-cooled crucible in a magnetic levitation melting furnace. Take out the mold with a temperature of 500 °C from the heating furnace and place it on the vibrating plate under the water-cooled crucible to fix it. After closing the furnace door, use a vacuum pump to evacuate, and then introduce nitrogen to clean the furnace chamber. Repeat the operations of evacuating and introducing nitrogen 2 - 3 times to ensure the purity of the furnace atmosphere. Then introduce hydrogen into the furnace at a rate of 120 mL / min. Turn on the heating device of the magnetic levitation melting furnace, control the heating program of the magnetic levitation melting furnace, and heat up to 2400 - 2500 °C in 7 - 8 min. The raw materials are completely melted into a metal liquid (the metal liquid will levitate in the center of the crucible). Continue to keep warm at this temperature for 5 min, then turn the handle and pour the metal liquid into the funnel of the mold. After pouring, turn off the heating device, turn on the vibrator under the mold and vibrate for 10 min, then turn off the vibrator and let the metal liquid slowly condense to obtain an Ir ingot.

[0071] In this embodiment, through the magnetic levitation melting process, the entire melting process only takes 12 - 14 min. The obtained Ir ingot has no oxide layer on the surface and no pores inside. Through GDMS inspection, no new impurities are introduced into the Ir ingot, the oxygen content can be controlled within 30 ppm, and the purity reaches 99.99%. The overall loss rate of Ir metal during the melting process is 0.94%.

[0072] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for recovering Ru or Ir from waste materials, characterized in that, It includes the following steps: 1) After the waste raw materials are successively subjected to sandblasting, crushing, pickling, cleaning and drying, raw materials are obtained; wherein: the waste raw materials are used residual targets and / or waste materials of refractory oxide crystal growth vessels; 2) The raw materials are added into a crucible and placed in a magnetic levitation melting furnace; after the mold is preheated, it is placed directly below the crucible; after vacuum pumping, an inert atmosphere and hydrogen are introduced, magnetic levitation melting is started, and after the temperature is raised to the melting temperature, heat preservation is carried out to obtain molten metal; then, without closing the magnetic levitation, the molten metal is poured into the mold, and after pouring, the magnetic levitation is closed, the vibrator below the mold is started to vibrate the mold, and after the vibrator is closed, the molten metal is condensed to obtain the recycled ruthenium ingot or iridium ingot.

2. The method for recovering Ru or Ir from waste materials according to claim 1, wherein In the step (1), the crushing is carried out until the fragment size is ≤100 mm.

3. The method for recovering Ru or Ir from waste materials according to claim 1, characterized in that, In the step (1), the pickling solution used for pickling is composed of nitric acid and hydrochloric acid with a volume ratio of 1:(2 - 4); the concentration of nitric acid is 20 - 30 wt%, and the concentration of hydrochloric acid is 15 - 20 wt%.

4. The method for recovering Ru or Ir from waste materials according to claim 1, characterized in that, In the step (1), the temperature of the pickling is 100 - 120 °C, and the pickling time is 1.5 - 4 h.

5. The method for recovering Ru or Ir from waste materials according to claim 1, wherein In the step (2), during the process of adding the raw materials into the crucible, small pieces of raw materials are placed at the bottom layer, and large pieces of raw materials are placed at the upper layer.

6. The method for recovering Ru or Ir from waste materials according to claim 1, wherein, In the step (2), the preheating temperature of the mold is 500 - 600 °C.

7. The method for recovering Ru or Ir from waste materials according to claim 1, wherein In the step (2), the introduction speed of hydrogen is 50 - 150 mL / min.

8. The method for recovering Ru or Ir from waste materials according to claim 1, characterized in that, In the step (2), the melting temperature is 2380 - 2500 °C, and the heat preservation time is 3 - 5 min.

9. The method for recovering Ru or Ir from waste materials according to claim 1, characterized in that, In the step (2), the vibration time of the mold is 10 - 15 min.

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