Method for directly regenerating germanium and bismuth from BGO waste target material

Abstract

The invention discloses a method for directly regenerating germanium and bismuth from a BGO waste target material, which belongs to the technical field of resource regeneration, and has the beneficial effects that through a self-made reduction-vacuum integrated furnace, through the processes of ball milling, charging, nitrogen feeding and oxygen discharging, reduction and ingot casting, nitrogen feeding and hydrogen discharging, furnace shutdown and discharging and the like, the germanium and bismuth can be directly regenerated; according to the method, germanium and bismuth metals can be directly regenerated from the BGO waste target material; and the method has the advantages of high direct recovery rate of germanium and bismuth, simple process operation, low production cost, no secondary pollution and the like.

Description

Technical Field

[0001] The invention relates to the technical field of resource recycling, in particular to a method for directly regenerating germanium and bismuth from BGO waste target materials. Background Art

[0002] BGO is the abbreviation of bismuth germanate, the general name of Bi2O3-GeO2 series compounds. It is a colorless and transparent inorganic oxide crystal with a cubic structure. It is insoluble in water. When excited by high-energy particles or high-energy rays (x-rays, y-rays), it can emit green fluorescence with a peak wavelength of 480nm. By recording the intensity and position of the fluorescence, the energy and position of the incident electrons, gamma rays, etc. can be calculated; this is the "eye" function of BGO, which can be used as a "detector" for high-energy particles.

[0003] With the discovery of BGO's luminescent properties, research on its scintillation properties and its application as a detection material for X-rays, gamma rays, positrons and charged particles has sprung up. BGO crystals have the advantages of strong radiation blocking ability, high scintillation efficiency, excellent energy resolution and non-deliquescent properties. They are a new generation of scintillation crystal materials with excellent performance. They are widely used in high-energy physics, nuclear physics, space physics, nuclear medicine, geological exploration and other industrial fields. Their application scope and volume have begun to gradually increase.

[0004] At present, the production utilization rate of BGO target materials and back-end products in the industry is not high. Some BGO targets will become waste during production and use, resulting in resource waste. The main components of BGO waste targets are bismuth germanate and other trace impurities. Germanium is a high-value rare metal and strategic, and bismuth is also an important metal resource. Therefore, the germanium and bismuth in this part of waste targets must be fully recycled and utilized.

[0005] The existing BGO waste target regeneration technology mainly adopts hydrometallurgical technology, that is, after the waste target material is crushed, it is chlorinated and distilled with hydrochloric acid to obtain germanium tetrachloride, and then high-purity germanium dioxide or zone melting germanium ingots and other products are produced by conventional germanium production process; the bismuth enters the distillation waste acid, and after neutralization and precipitation, bismuth concentrate is obtained, and then sent to the bismuth plant for bismuth extraction.

[0006] The significant disadvantages of the above wet recovery process are long process flow, large amount of acid and alkali, high cost, high environmental pressure, etc. In summary, it is very important and meaningful to develop a simple and efficient process for recovering germanium and bismuth metals from BGO waste targets. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for regenerating germanium and bismuth from BGO waste target material.

[0008] The present invention comprises the following steps:

[0009] 1) Ball milling: crush the waste BGO target and ball mill it to get BGO powder;

[0010] 2) Loading: The BGO powder obtained in the ball milling step is placed in a graphite container and placed in a heating chamber in a homemade reduction-vacuum distillation integrated furnace;

[0011] 3) Nitrogen ventilation and oxygen exhaust: nitrogen is introduced into the furnace to exhaust the air in the furnace;

[0012] 4) Reduction and ingot casting: Stop introducing nitrogen and introduce hydrogen into the furnace; in the first stage, the heating chamber is heated to the first stage set temperature and then kept at a constant temperature; in the second stage, the heating chamber is heated to the second stage set temperature and then kept at a constant temperature; in the third stage, the heating chamber is heated to the third stage set temperature and then kept at a constant temperature; in the fourth stage, the heating chamber is heated to the fourth stage set temperature and then kept at a constant temperature; in the fifth stage, the heating chamber is heated to the fifth stage set temperature and then kept at a constant temperature;

[0013] 5) Nitrogen ventilation to discharge hydrogen: stop introducing hydrogen and introduce nitrogen to discharge hydrogen in the furnace;

[0014] 6) Vacuum distillation: Stop the nitrogen gas and start the vacuum system. After the pressure in the collection chamber of the furnace drops to a certain negative pressure, continue to keep the heating chamber at a certain high temperature range and keep the temperature constant;

[0015] 7) Shut down the furnace and discharge the materials: turn off the vacuum system, introduce nitrogen, and turn off the heating system of the heating chamber. Stop introducing nitrogen after the heating chamber and the collecting chamber naturally cool down to below the safe temperature. After the heating chamber and the collecting chamber continue to naturally cool down to a lower temperature range, open the reduction-vacuum distillation integrated furnace, and the germanium ingot can be taken out from the graphite boat in the heating chamber. After conventional surface corrosion, it can be sold or further purified to produce the melted germanium ingot for sale. Bismuth metal can be obtained in the collecting chamber and can be sold directly.

[0016] The present invention increases the surface area of ​​the BGO material through the ball milling step, so as to improve the speed and efficiency of the subsequent hydrogen reduction reaction on the material.

[0017] The present invention uses the graphite boat as a container through the loading step, which can also play the role of a medium frequency induction heating source without causing pollution. Compared with a quartz boat, the graphite boat is easier to separate when the germanium ingot is discharged.

[0018] The present invention discharges the air in the reduction-vacuum integrated furnace with nitrogen at room temperature through the nitrogen-passing and oxygen-discharging step, thereby eliminating the explosion hazard when hydrogen is passed.

[0019] The present invention reduces a small part of bismuth germanate in the material to germanium metal and bismuth metal slowly by passing hydrogen at a relatively low temperature in the first stage through the reduction and ingot casting steps, wherein bismuth also adheres to BGO powder in the form of liquid bismuth beads, thereby reducing the scouring and entrainment of BGO powder by airflow; from the second stage to the fourth stage, the temperature is gradually increased and constant temperature reduction is performed in three different temperature sections, so as to reduce energy consumption by a stepwise temperature reduction method; in the fifth stage, the heating chamber is heated to 950-1000° C., so as to increase the temperature to further fully reduce the germanium and bismuth, and to completely melt the germanium and bismuth to form an alloy solution.

[0020] The present invention uses nitrogen to discharge hydrogen in the reduction-vacuum integrated furnace through the nitrogen-passing hydrogen discharge step, thereby eliminating potential safety hazards during vacuum distillation.

[0021] The present invention uses the characteristic of germanium having a higher boiling point than bismuth to evaporate bismuth and condense it into liquid in a collection chamber through the vacuum distillation step under negative pressure, and the germanium remains in the graphite container in liquid state, thereby achieving the purpose of separating germanium from bismuth.

[0022] The product obtained by the furnace stopping and discharging step meets the quality requirements of ZGe-1 brand zone melting germanium ingot in the industry standard GB / T 11071 "Zone Melting Germanium Ingot"; the obtained metal bismuth can be sold directly.

[0023] In summary, the present invention uses a self-made reduction-vacuum integrated furnace, and can directly produce germanium ingots only through pyrolysis, which are sold after conventional surface corrosion or produced by regional melting and purification. The germanium-bismuth recovery process is simple, and the production is efficient and low-cost; and the metal recovery is thorough, with a germanium recovery rate of more than 98.5%; and a bismuth recovery rate of more than 96%. At the same time, the present invention has obvious cleaning characteristics: only nitrogen, hydrogen, etc. are used in the auxiliary materials, and no wastewater and waste residue are generated in the entire process, with significant environmental benefits.

[0024] Preferably, in the ball milling step, the BGO powder after ball milling is sieved through 150 mesh. The purpose of material particle size control is to increase the contact area between the material and hydrogen and improve the reaction rate.

[0025] Preferably, in the charging step, the BGO powder charging thickness is 3 to 8 cm to ensure the sufficiency of the subsequent reduction reaction.

[0026] Preferably, in the nitrogen-passing and oxygen-exhausting step, nitrogen is passed into the BGO powder in the heating chamber to exhaust the air in the reduction-vacuum integrated furnace, so as to eliminate the explosion hazard when hydrogen is passed.

[0027] Preferably, in the reduction and ingot casting steps, the heating chamber is heated to 580-620°C in the first stage and then kept at a constant temperature for 2-3 hours; the heating chamber is heated to 650-690°C in the second stage and kept at a constant temperature for 2-3 hours; the heating chamber is heated to 730-770°C in the third stage and kept at a constant temperature for 2-3 hours; the heating chamber is heated to 830-870°C in the fourth stage and kept at a constant temperature for 3-4 hours; the heating chamber is heated to 950-1000°C in the fifth stage and kept at a constant temperature for 1-2 hours;

[0028] Preferably, in the nitrogen-passing and hydrogen-exhausting step, the hydrogen is stopped and nitrogen is passed for 20 to 30 minutes to drive out the hydrogen in the furnace, so as to eliminate the potential safety hazard during vacuum distillation.

[0029] Preferably, in the vacuum distillation step, after the vacuum degree in the furnace is less than 50 Pa, the temperature of the heating chamber is controlled to be 950-1000° C. and kept constant for 4-6 hours;

[0030] Preferably, in the vacuum distillation step, the vacuum system is turned off and nitrogen is introduced, the heating system is turned off, and the introduction of nitrogen is stopped after the temperatures of the heating chamber and the collection chamber are no greater than 150° C.;

[0031] Preferably, in the furnace stopping and discharging step, after the temperature of the heating chamber and the collecting chamber is no more than 40° C., the furnace can be opened to take out the germanium ingot and the metallic bismuth.

[0032] Beneficial Effects

[0033] A method for directly regenerating germanium and bismuth from BGO waste target material prepared by the technical solution of the present invention has the following beneficial effects:

[0034] In this case, a self-made reduction-vacuum integrated furnace is used, and the processes include ball milling, charging, nitrogen oxygen removal, reduction and ingot casting, nitrogen hydrogen removal, furnace shutdown and discharge. This method can directly regenerate germanium and bismuth metals from BGO waste target materials; and has the advantages of high direct recovery rate of germanium and bismuth, simple process operation, low production cost, and no secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure of a homemade reduction-vacuum integrated furnace for the method of directly regenerating germanium and bismuth from BGO waste target materials described in the present invention.

[0036] Figure 2 The figure is a schematic diagram of the process flow of a method for directly regenerating germanium and bismuth from BGO waste target material according to the present invention.

[0037] Figure 3 This is a schematic diagram of the equations for the reduction and ingot casting steps of the method for directly regenerating germanium and bismuth from BGO waste target material according to the present invention.

[0038] In the figure: 1. Collection chamber; 2. Heating chamber; 3. Vacuum system; 4. Heating system; DETAILED DESCRIPTION

[0039] The reduction-vacuum integrated furnace used in this case includes a collection chamber 1, a heating chamber 2, a vacuum system 3, a heating system 4, etc. The collection chamber 1 is located on one side of the heating chamber 2. The collection chamber 1 and the heating chamber 2 can be connected through a pipeline 6. The vacuum system 3 is connected to the collection chamber 1 to extract the gas in the collection chamber 1 and the heating chamber 2 to reduce the pressure in the reduction-vacuum integrated furnace; the heating system 4 is arranged in the heating chamber 2 to achieve heating and cooling in the heating chamber 2. The application of the vacuum system 3 and the heating system 4 in the reduction-vacuum integrated furnace belongs to the prior art. The reduction-vacuum integrated furnace used in the present invention only uses the vacuum system 3 and the heating system 4 in the prior art, and does not innovate the structure in each system. Therefore, the internal structure of the vacuum system 3 and the heating system 4 will not be described in detail. It also includes a control system (not shown in the figure) for controlling the vacuum system 3 and the heating system 4 to work normally.

[0040] Example 1

[0041] A method for regenerating germanium and bismuth from spent BGO targets comprises:

[0042] 1) Ball milling: crush the waste BGO target material and ball mill it to obtain BGO powder, which is then sieved through 150 mesh;

[0043] 2) Loading: The BGO powder obtained in the ball milling step is placed in a graphite container and placed in a heating chamber in a homemade reduction-vacuum distillation integrated furnace, with a loading thickness of 8 cm;

[0044] 3) Nitrogen ventilation and oxygen removal: nitrogen is introduced into the furnace for 15 minutes;

[0045] 4) Reduction and ingot casting: Stop nitrogen and introduce hydrogen into the furnace; in the first stage, the heating chamber is heated to 620°C and kept at a constant temperature for 2 hours; in the second stage, the heating chamber is heated to 690°C and kept at a constant temperature for 2 hours; in the third stage, the heating chamber is heated to 770°C and kept at a constant temperature for 2 hours; in the fourth stage, the heating chamber is heated to 870°C and kept at a constant temperature for 3 hours; in the fifth stage, the heating chamber is heated to 1000°C and kept at a constant temperature for 1 hour;

[0046] 5) Nitrogen-assisted hydrogen removal: Stop introducing hydrogen and introduce nitrogen for 30 minutes;

[0047] 6) Vacuum distillation: stop introducing nitrogen, start the vacuum system, wait until the pressure in the collection chamber of the furnace is less than or equal to 48Pa, continue to maintain the temperature of the heating chamber at 1000°C, and keep the constant temperature for 4 hours;

[0048] 7) Stop the furnace and discharge the materials: turn off the vacuum system, introduce nitrogen, and turn off the heating system of the heating chamber. Stop introducing nitrogen after the heating chamber and the collecting chamber naturally cool down to 150°C; turn on the reduction-vacuum distillation integrated furnace after the heating chamber and the collecting chamber naturally cool down to 40°C, and then take out the germanium ingot from the graphite boat in the heating chamber and sell it after conventional surface corrosion; metallic bismuth can be obtained in the collecting chamber and sold directly.

[0049] By using the method of this embodiment, the final direct recovery rate of germanium is 98.2%, and the recovery rate of bismuth is 95.8%.

[0050] Example 2

[0051] 1) Ball milling: crush the waste BGO target material and ball mill it to obtain BGO powder, which is then sieved through 150 mesh;

[0052] 2) Loading: The BGO powder obtained in the ball milling step is placed in a graphite container and placed in a heating chamber in a homemade reduction-vacuum distillation integrated furnace, with a loading thickness of 5 cm;

[0053] 3) Nitrogen ventilation and oxygen removal: nitrogen is introduced into the furnace for 15 minutes;

[0054] 4) Reduction and ingot casting: Stop nitrogen and introduce hydrogen into the furnace; in the first stage, the heating chamber is heated to 600°C and kept at a constant temperature for 2.5 hours; in the second stage, the heating chamber is heated to 670°C and kept at a constant temperature for 2.5 hours; in the third stage, the heating chamber is heated to 750°C and kept at a constant temperature for 2.5 hours; in the fourth stage, the heating chamber is heated to 850°C and kept at a constant temperature for 3.5 hours; in the fifth stage, the heating chamber is heated to 980°C and kept at a constant temperature for 2 hours;

[0055] 5) Nitrogen-assisted hydrogen removal: Stop introducing hydrogen and introduce nitrogen for 25 minutes;

[0056] 6) Vacuum distillation: Stop the nitrogen gas, start the vacuum system, wait until the pressure in the collection chamber is less than or equal to 45Pa, continue to maintain the heating chamber temperature at 980°C, and keep the constant temperature for 5 hours;

[0057] 7) Stop the furnace and discharge the materials: turn off the vacuum system, introduce nitrogen, and turn off the heating system of the heating chamber. Stop introducing nitrogen after the heating chamber and the collecting chamber naturally cool down to 130°C; turn on the reduction-vacuum distillation integrated furnace after the heating chamber and the collecting chamber naturally cool down to 40°C, and take out the germanium ingot from the graphite boat in the heating chamber. After conventional surface corrosion, it can be sold or produced into zone melting germanium ingots for sale after regional smelting and purification. Bismuth metal can be obtained in the collecting chamber and can be sold directly.

[0058] By using the method of this embodiment, the final direct recovery rate of germanium is 97.8%, and the recovery rate of bismuth is 96.5%.

[0059] Example 3

[0060] 1) Ball milling: crush the waste BGO target material and ball mill it to obtain BGO powder, which is then sieved through 150 mesh;

[0061] 2) Loading: The BGO powder obtained in the ball milling step is placed in a graphite container and placed in a heating chamber in a homemade reduction-vacuum distillation integrated furnace, with a loading thickness of 3 cm;

[0062] 3) Nitrogen ventilation and oxygen removal: nitrogen is introduced into the furnace for 10 minutes;

[0063] 4) Reduction and ingot casting: Stop nitrogen and introduce hydrogen into the furnace; in the first stage, the heating chamber is heated to 580°C and kept at this temperature for 3 hours; in the second stage, the heating chamber is heated to 650°C and kept at this temperature for 3 hours; in the third stage, the heating chamber is heated to 730°C and kept at this temperature for 3 hours; in the fourth stage, the heating chamber is heated to 830°C and kept at this temperature for 4 hours; in the fifth stage, the heating chamber is heated to 960°C and kept at this temperature for 2 hours;

[0064] 5) Nitrogen-assisted hydrogen removal: Stop introducing hydrogen and introduce nitrogen for 20 minutes;

[0065] 6) Vacuum distillation: Stop the nitrogen gas, start the vacuum system, wait until the pressure in the collection chamber is less than or equal to 40Pa, continue to maintain the heating chamber temperature at 960°C for 6 hours;

[0066] 7) Stop the furnace and discharge the materials: turn off the vacuum system, introduce nitrogen, and turn off the heating system of the heating chamber. Stop introducing nitrogen after the heating chamber and the collecting chamber naturally cool down to 100°C; turn on the reduction-vacuum distillation integrated furnace after the heating chamber and the collecting chamber naturally cool down to 35°C, and take out the germanium ingot from the graphite boat in the heating chamber. After conventional surface corrosion, it can be sold or after regional smelting and purification, it can be produced into regional melting germanium ingots for sale; metallic bismuth can be obtained in the collecting chamber and can be sold directly.

[0067] By using the method of this embodiment, the final direct recovery rate of germanium is 96.7%, and the recovery rate of bismuth is 96.2%.

[0068] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention; on the contrary, any changes and modifications made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A method for directly regenerating germanium and bismuth from BGO waste target material, characterized in that The following steps are involved: 1) Ball milling: crush the waste BGO target and ball mill it to get BGO powder; 2) Loading: The BGO powder obtained in the ball milling step is placed in a graphite container and placed in a heating chamber in a homemade reduction-vacuum distillation integrated furnace; 3) Nitrogen ventilation and oxygen exhaust: nitrogen is introduced into the furnace to exhaust the air in the furnace; 4) Reduction and ingot casting: Stop introducing nitrogen and introduce hydrogen into the furnace; in the first stage, the heating chamber is heated to the first stage set temperature and then kept at a constant temperature; in the second stage, the heating chamber is heated to the second stage set temperature and then kept at a constant temperature; in the third stage, the heating chamber is heated to the third stage set temperature and then kept at a constant temperature; in the fourth stage, the heating chamber is heated to the fourth stage set temperature and then kept at a constant temperature; in the fifth stage, the heating chamber is heated to the fifth stage set temperature and then kept at a constant temperature; 5) Nitrogen ventilation to exhaust hydrogen: stop introducing hydrogen and introduce nitrogen to exhaust hydrogen in the furnace; 6) Vacuum distillation: Stop the nitrogen gas and start the vacuum system. After the pressure in the collection chamber of the furnace drops to a certain negative pressure, continue to keep the heating chamber at a certain high temperature range and keep the temperature constant; 7) Shut down the furnace and discharge the materials: turn off the vacuum system, introduce nitrogen, and turn off the heating system of the heating chamber. Stop introducing nitrogen after the heating chamber and the collecting chamber naturally cool down to below the safe temperature. After the heating chamber and the collecting chamber continue to naturally cool down to a lower temperature range, open the reduction-vacuum distillation integrated furnace, and the germanium ingot can be taken out from the graphite boat in the heating chamber. After conventional surface corrosion, it can be sold or further purified to produce the melted germanium ingot for sale. Bismuth metal can be obtained in the collecting chamber and can be sold directly.

2. A method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the ball milling step, the BGO powder after the ball milling is crushed and sieved through 150 mesh.

3. A method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the charging step, the BGO powder charging thickness is 3 to 8 cm.

4. A method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the nitrogen-passing and oxygen-exhausting step, the nitrogen passing time is 10 to 15 minutes.

5. A method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the reduction and ingot casting steps, in the first stage, the heating chamber is heated to 580-620°C and then kept at a constant temperature for 2-3 hours; in the second stage, the heating chamber is heated to 650-690°C and kept at a constant temperature for 2-3 hours; in the third stage, the heating chamber is heated to 730-770°C and kept at a constant temperature for 2-3 hours; in the fourth stage, the heating chamber is heated to 830-870°C and kept at a constant temperature for 3-4 hours; in the fifth stage, the heating chamber is heated to 950-1000°C and kept at a constant temperature for 1-2 hours.

6. A method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the nitrogen-passing and hydrogen-expelling step, the nitrogen passing time is 20 to 30 minutes.

7. A method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the vacuum distillation step, after the vacuum degree in the furnace is less than 50 Pa, the temperature of the heating chamber is controlled to be 950-1000° C. and kept constant for 4-6 hours.

8. The method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the furnace stopping and discharging step, the vacuum system is turned off and nitrogen is introduced, the heating system is turned off, and the introduction of nitrogen is stopped after the temperatures of the heating chamber and the collecting chamber are no greater than 150°C.

9. A method for directly regenerating germanium and bismuth from BGO waste target according to claim 1, characterized in that In the step of stopping the furnace and discharging materials, after the temperature of the heating chamber and the collecting chamber is no more than 40° C., the furnace can be opened to take out the germanium ingot and the metallic bismuth.

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