Sustainable beryllium waste recycling method

Abstract

The invention discloses a sustainable beryllium waste recycling method, and belongs to the technical field of beryllium materials. The method comprises the following steps: pickling beryllium waste; carrying out ultrasonic cleaning on the pickled beryllium waste, and then carrying out vacuum drying; the beryllium waste materials subjected to vacuum drying are subjected to airflow impact, and beryllium powder is obtained; the beryllium powder and the salpeter solution are mixed and stirred for 23-27 h at the temperature of 70-90 DEG C according to the proportion that 18-24 L of salpeter solution is added into every 2-4 kg of beryllium powder, and then suction filtration, washing, vacuum drying and mixed screening are sequentially conducted; and sequentially carrying out cold isostatic pressing, degassing, hot isostatic pressing and acid pickling on the beryllium powder subjected to mixed screening. The components of the prepared beryllium powder and the performance of the beryllium blank can both meet the product requirements, the beryllium waste industrial treatment capacity is high, the utilization rate of limited beryllium resources is guaranteed, the recycling cost is low, the purposes of quality improvement and efficiency improvement are achieved, sustainable development of the beryllium material industry is facilitated, and support is provided for the market competitiveness of enterprises.

Description

Technical Field

[0001] The present invention belongs to the technical field of beryllium materials, and in particular relates to a sustainable beryllium waste recycling and utilization method. Background Art

[0002] Beryllium metal is a strategic and critical material, boasting exceptional properties such as low density, high melting point, and high specific stiffness. It also boasts the smallest thermal neutron absorption cross-section of any metal and exceptional nuclear and thermal properties, earning it the reputation of a space metal and a metal of the nuclear age. Beryllium has crucial applications in aerospace and strategic nuclear energy. However, beryllium and its compounds are highly toxic and classified as Class I pollutants. Furthermore, its scarcity and high cost severely restrict the development of the beryllium material industry and the expansion of its applications.

[0003] Since beryllium material production produces beryllium waste of different properties, such as beryllium metal scraps sintered at high temperature and high pressure during material processing and unqualified products and scraps produced during the forming process, existing recycling methods are only applicable to the recycling and reuse of beryllium waste of a certain nature, and the recycling cost is high, and the ability to industrially process beryllium waste is low, which cannot support the market competitiveness of enterprises. Summary of the Invention

[0004] The purpose of the present invention is to provide a sustainable beryllium waste recycling and reuse method. The composition of the beryllium powder prepared by this method and the performance of the beryllium blank can meet product requirements. The ability to industrially process beryllium waste is high, the utilization rate of limited beryllium resources is guaranteed, and the recycling cost is low, achieving the purpose of improving quality and efficiency, which is beneficial to the sustainable development of the beryllium material industry and provides support for the market competitiveness of enterprises.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A sustainable beryllium waste recycling and cyclic utilization method, the sustainable beryllium waste recycling and cyclic utilization method comprising the following steps:

[0007] Step S1, using a nitric acid solution with a mass concentration of 25-35% to pickle the beryllium waste for 17-24 hours;

[0008] Step S2, ultrasonically cleaning the pickled beryllium waste at a temperature of 40-50° C. and a frequency of 28-29 kHz, and then vacuum drying;

[0009] Step S3, subjecting the vacuum-dried beryllium waste to airflow impact to obtain beryllium powder;

[0010] Step S4, adding 18 to 24 L of nitric acid solution for every 2 to 4 kg of beryllium powder, stirring the beryllium powder and the nitric acid solution at a temperature of 70 to 90° C. for 23 to 27 hours, and then filtering, rinsing, vacuum drying, and sieving in sequence;

[0011] Step S5: cold isostatic pressing, degassing, hot isostatic pressing and pickling are performed on the mixed and sieved beryllium powder in sequence to obtain a beryllium blank.

[0012] Furthermore, in the step S1, the beryllium waste includes beryllium processing chips and beryllium slag;

[0013] The beryllium slag is crushed unqualified waste beryllium and leftover beryllium materials.

[0014] Furthermore, in the step S2, the degreasing medium in the ultrasonic cleaning is CT-206B weak alkaline degreasing agent;

[0015] The ultrasonic cleaning time is 45 to 55 minutes.

[0016] Furthermore, in step S2, the vacuum degree of the vacuum drying is 2×10 -2 ~6×10 -2 Pa, the vacuum drying temperature is 110-130°C, and the vacuum drying time is 12-15h.

[0017] Furthermore, in step S3, the purity of the nitrogen gas impacted by the airflow is greater than 99.1%, and the pressure is 0.9-1.1 MPa.

[0018] Furthermore, in the step S4, the nitric acid solution includes concentrated nitric acid with a concentration of 65-71% and water;

[0019] The volume ratio of the concentrated nitric acid to water is 1.5-1.9:15-19.

[0020] Furthermore, in step S4, the filtration pressure is 1×10 4 ~4×10 4 Pa, temperature is 20-30℃, time is 1-3h;

[0021] In the step S4, the flushing medium is water;

[0022] In step S4, the vacuum degree of the vacuum drying is 2×10 -2 ~6×10 -2 Pa, temperature is 80-90℃, time is 20-25h;

[0023] In step S4, a double sieve of 280-300 mesh and 220-240 mesh is used for mixed screening.

[0024] Furthermore, in step S5, the purity of the mixed beryllium powder after sieving is ≥98.6%.

[0025] Furthermore, in step S5, the cold isostatic pressing pressure is 190-220 MPa, and the time is 15-19 minutes;

[0026] In step S5, the degassing temperature is 650-700° C. and the degassing time is 8-10 hours;

[0027] In step S5, the hot isostatic pressing pressure is 110-120 MPa, the temperature is 1040-1080° C., and the time is 6-8 hours;

[0028] In step S5, pickling is performed using a nitric acid solution with a mass concentration of 25-35%.

[0029] Furthermore, in step S5, the beryllium blank has a tensile strength of ≥495 MPa, a yield strength of ≥450 MPa, an elastic modulus of ≥291000 MPa, an elongation of ≥1.8%, and a hardness HRB of ≥90.

[0030] In summary, the solution proposed in the present invention has the following technical effects:

[0031] The present invention realizes the recovery of beryllium metal waste generated in the beryllium material processing process through high-temperature and high-pressure sintering, as well as unqualified products and scraps generated in the forming process, and solves the problems of removing metal impurities and grease from beryllium waste, and the difficulty in reshaping the recovered powder, so that the composition of the recovered beryllium powder and the performance of the beryllium blank can meet product requirements, thereby improving the ability to industrially process beryllium waste and the utilization rate of limited beryllium resources; the present invention can greatly reduce costs, improve quality and efficiency, ensure the sustainable development of the beryllium material industry, and provide logistical support for improving the market competitiveness of enterprises. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] This embodiment provides a sustainable beryllium waste recycling and cyclic utilization method, which includes the following steps:

[0034] Step S1: using a nitric acid solution with a mass concentration of 25-35% to pickle the beryllium waste for 17-24 hours.

[0035] The beryllium waste in this embodiment includes beryllium processing chips and beryllium slag, which is crushed unqualified waste beryllium and beryllium scraps. The beryllium processing chips in this embodiment are collected under a negative pressure greater than 18,500 Pa using an automatic collection device with backflush filtration, with a collection rate of >93%. Under closed conditions, a jaw crusher is used to crush the unqualified beryllium products and scraps into beryllium slag.

[0036] In this embodiment, the mass concentration of the nitric acid solution during the pickling process is controlled to be 25-35%, and the time is 17-24 hours (i.e., hours), so that the nitric acid solution and impurities (such as Fe, etc.) in the beryllium waste can fully and stably react, thereby avoiding the generation of a large amount of harmful gases during the pickling process, reducing acid mist during the pickling process, and ensuring production safety.

[0037] Step S2: ultrasonically clean the pickled beryllium waste at a temperature of 40-50° C. and a frequency of 28-29 kHz, and then vacuum dry the waste beryllium.

[0038] In order to effectively remove impurities and pickling solution remaining on the surface of the beryllium waste, ensure the cleaning effect, and avoid damaging the surface of the beryllium waste, this embodiment uses CT-206B weak alkaline degreasing agent as the degreasing medium in an ultrasonic cleaning tank. The pickled beryllium waste (including beryllium processing chips and beryllium slag) is ultrasonically cleaned for 45 to 55 minutes at a constant temperature of 40 to 50°C and a frequency of 28 to 29 kHz.

[0039] In order to quickly vaporize the water at a lower temperature and prevent the beryllium waste from being oxidized, the vacuum degree of the vacuum drying is controlled at 2×10 -2 ~6×10 -2 To ensure the quality and effect of vacuum drying, the vacuum drying temperature is controlled at 110-130°C in this embodiment to fully vaporize the water and effectively dry it. The drying time is controlled at 12-15 hours, thereby ensuring the drying quality and improving production efficiency.

[0040] Step S3: performing air flow impact on the vacuum-dried beryllium waste to obtain beryllium powder.

[0041] In order to prevent oxidation during the preparation of beryllium powder, avoid chemical reactions between impurity gases and beryllium, and at the same time crush the beryllium waste into fine powder particles to obtain an ideal particle size distribution and meet the beryllium powder particle size requirements of different applications, the air flow impact parameter conditions in this embodiment are: nitrogen purity >99.1%, and the air flow impact pressure is 0.9-1.1 MPa.

[0042] Step S4: adding 18 to 24 L of nitric acid solution to every 2 to 4 kg of beryllium powder, stirring the beryllium powder and the nitric acid solution at a temperature of 70 to 90° C. for 23 to 27 hours, and then filtering, rinsing, vacuum drying, and sieving in sequence.

[0043] To fully remove impurity elements (such as Fe, Al, etc.) and surface oxide films from the beryllium powder, regularize the beryllium powder particle morphology, ensure a stable chemical state and microstructure on the beryllium powder surface, and enhance the uniformity of the beryllium powder particles, this embodiment uses a ratio of 2-4 kg of beryllium powder to 18-24 L of nitric acid solution, followed by high-temperature (70-90°C) acid washing for 23-27 hours. The nitric acid solution comprises concentrated nitric acid with a concentration of 65-71% and water, with a volume ratio of 1.5-1.9:15-19.

[0044] In order to facilitate the washing of the acid on the powder, this embodiment uses a 0.5-1.5 μm filter cloth for filtration, and the filtration pressure is 1×10 4 ~4×10 4 Pa, temperature is 20-30℃, time is 1-3h.

[0045] In this embodiment, the vacuum degree of vacuum drying is controlled at 2×10 -2 ~6×10 -2 The purpose of the vacuum drying process is to quickly vaporize the water at a relatively low temperature to prevent oxidation of the beryllium waste. Furthermore, in order to fully vaporize the water, effectively dry the waste, ensure drying quality, and improve production efficiency, the vacuum drying process in this embodiment is controlled at a temperature of 80-90°C and a time of 20-25 hours. Water is used for rinsing in this embodiment.

[0046] In order to ensure the uniformity of beryllium powder particles and facilitate subsequent molding, this embodiment uses double sieves of 280-300 mesh and 220-240 mesh for mixed screening.

[0047] Step S5: cold isostatic pressing, degassing, hot isostatic pressing and pickling are performed on the mixed and sieved beryllium powder in sequence to obtain a beryllium blank.

[0048] The purity of the sieved beryllium powder in this embodiment is ≥98.6%. In order to improve the density of the beryllium powder and ensure a uniform internal structure of the beryllium powder blank, the cold isostatic pressing pressure in this embodiment is controlled to be 190-220 MPa and the time is 15-19 minutes.

[0049] In order to extract the gas in the beryllium billet and ensure the performance of the beryllium billet, the degassing temperature in this embodiment is controlled to be 650-700° C. and the time is 8-10 hours.

[0050] In order to ensure the uniformity of the beryllium billet, improve the densification degree and mechanical properties of the beryllium billet, and optimize the microstructure of the beryllium billet, the hot isostatic pressing pressure in this embodiment is controlled to be 110-120 MPa, the temperature to be 1040-1080° C., and the time to be 6-8 hours.

[0051] In this step, a nitric acid solution with a mass concentration of 25-35% is used for pickling to facilitate the removal of the ladle jacket.

[0052] The beryllium blank in this embodiment has a tensile strength of ≥495 MPa, a yield strength of ≥450 MPa, an elastic modulus of ≥291000 MPa, an elongation of ≥1.8%, and a hardness HRB of ≥90.

[0053] The technical solution of the above embodiment is described below through specific examples:

[0054] Example 1:

[0055] Step S1: using a nitric acid solution with a mass concentration of 30% to pickle beryllium chips for 20 hours.

[0056] Step S2: At a temperature of 45°C and a frequency of 29 kHz, use CT-206B weak alkaline degreasing agent to ultrasonically clean the pickled beryllium chips for 50 minutes, then -2 The sample was dried under vacuum for 13 h at a vacuum degree of 0.05 Pa and a temperature of 120°C.

[0057] Step S3: Under a pressure of 1.0 MPa, nitrogen with a purity of 99.15% is used to perform airflow impact on the vacuum-dried beryllium chips to obtain beryllium powder.

[0058] Step S4: add 18 L of nitric acid solution to every 4 kg of beryllium powder, stir the beryllium powder and nitric acid solution at 80°C for 25 hours, and then add 18 L of nitric acid solution to the beryllium powder at 3×10 4 Pa pressure and 25 ° C temperature, after filtering with 1 μm filter cloth for 2 hours, and then rinse with water, then, at 4 × 10 -2 The mixture was dried under vacuum for 22 hours at a temperature of 85° C. and a vacuum degree of 0.001 Pa. Finally, the mixture was sieved with a double sieve of 290 mesh and 230 mesh to obtain beryllium powder with a purity of 98.8%.

[0059] The nitric acid solution includes concentrated nitric acid with a concentration of 68% and water, and the volume ratio of concentrated nitric acid to water is 1.6:18.

[0060] Step S5: The sieved beryllium powder (i.e., beryllium powder with a purity of 98.8%) is cold isostatically pressed at a pressure of 200 MPa for 17 minutes, degassed at a temperature of 680° C. for 9 hours, and then hot isostatically pressed at a pressure of 115 MPa and 1060° C. for 7 hours. Finally, the beryllium powder is pickled with a nitric acid solution with a mass concentration of 30% to obtain a beryllium blank.

[0061] The beryllium blank of this embodiment has a tensile strength of 520 MPa, a yield strength of 470 MPa, an elastic modulus of 292,000 MPa, an elongation of 1.8%, and a hardness (HRB) of 92.

[0062] Example 2:

[0063] Step S1: using a nitric acid solution with a mass concentration of 25% to pickle beryllium chips for 17 hours.

[0064] Step S2: At a temperature of 40°C and a frequency of 28 kHz, use CT-206B weak alkaline degreasing agent to ultrasonically clean the pickled beryllium chips for 45 minutes. -2 The sample was dried under vacuum for 12 h at a vacuum degree of 0.05 Pa and a temperature of 110 °C.

[0065] Step S3: Under a pressure of 0.9 MPa, nitrogen with a purity of 99.2% is used to perform airflow impact on the vacuum-dried beryllium chips to obtain beryllium powder.

[0066] Step S4: add 18 L of nitric acid solution to every 2 kg of beryllium powder, stir the beryllium powder and nitric acid solution at 70°C for 23 hours, and then add 1×10 4 Pa pressure and 20 ° C temperature, after filtering with 0.5 μm filter cloth for 1 hour, and then rinse with water, then, at 2 × 10 -2 Pa and a temperature of 80° C., vacuum) for 20 h. Finally, the mixture was sieved using a double sieve of 280 mesh and 220 mesh to obtain beryllium powder with a purity of 98.7%.

[0067] The nitric acid solution includes concentrated nitric acid with a concentration of 65% and water, and the volume ratio of concentrated nitric acid to water is 1.9:15.

[0068] Step S5: The sieved beryllium powder (i.e., beryllium powder with a purity of 98.7%) is cold isostatically pressed at a pressure of 190 MPa for 15 minutes, degassed at a temperature of 650° C. for 8 hours, and then hot isostatically pressed at a pressure of 110 MPa and 1040° C. for 6 hours. Finally, the beryllium powder is pickled with a nitric acid solution with a mass concentration of 25% to obtain a beryllium blank.

[0069] The beryllium blank of this embodiment has a tensile strength of 510 MPa, a yield strength of 465 MPa, an elastic modulus of 291,000 MPa, an elongation of 2.1%, and a hardness (HRB) of 91.

[0070] Example 3:

[0071] Step S1: using a nitric acid solution with a mass concentration of 35% to pickle the beryllium slag for 24 hours.

[0072] Step S2: At a temperature of 50°C and a frequency of 28KHz, use CT-206B weak alkaline degreasing agent to ultrasonically clean the pickled beryllium chips for 55 minutes, then -2 The sample was dried under vacuum for 15 h at a vacuum degree of 0.05 Pa and a temperature of 130 °C.

[0073] Step S3: Under a pressure of 1.1 MPa, nitrogen with a purity of 99.3% is used to perform airflow impact on the vacuum-dried beryllium slag to obtain beryllium powder.

[0074] Step S4: add 24 L of nitric acid solution to every 2 kg of beryllium powder, stir the beryllium powder and nitric acid solution at 90°C for 27 hours, and then heat the mixture at 4×10 4 Pa pressure and 30 ° C temperature, after filtering with 1.5 μm filter cloth for 3 hours, and then rinsed with water, then, at 6 × 10 -2 The mixture was dried under vacuum for 25 hours at a temperature of 90° C. and a vacuum degree of 0.001 Pa. Finally, the mixture was sieved with a double sieve of 300 mesh and 240 mesh to obtain beryllium powder with a purity of 98.6%.

[0075] The nitric acid solution includes concentrated nitric acid with a concentration of 71% and water, and the volume ratio of concentrated nitric acid to water is 1.5:19.

[0076] Step S5: The sieved beryllium powder (i.e., beryllium powder with a purity of 98.6%) is cold isostatically pressed at a pressure of 220 MPa for 19 minutes, degassed at a temperature of 700° C. for 10 hours, and then hot isostatically pressed at a pressure of 120 MPa and 1080° C. for 8 hours. Finally, the beryllium powder is pickled with a nitric acid solution with a mass concentration of 35% to obtain a beryllium blank.

[0077] The beryllium blank of this embodiment has a tensile strength of 495 MPa, a yield strength of 450 MPa, an elastic modulus of 294,000 MPa, an elongation of 2.4%, and a hardness (HRB) of 90.

[0078] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A sustainable beryllium waste recycling and utilization method, characterized in that: The sustainable beryllium waste recycling and utilization method comprises the following steps: Step S1, using a nitric acid solution with a mass concentration of 25-35% to pickle the beryllium waste for 17-24 hours; Step S2, ultrasonically cleaning the pickled beryllium waste at a temperature of 40-50° C. and a frequency of 28-29 kHz, and then vacuum drying; Step S3, subjecting the vacuum-dried beryllium waste to airflow impact to obtain beryllium powder; Step S4, adding 18 to 24 L of nitric acid solution for every 2 to 4 kg of beryllium powder, stirring the beryllium powder and the nitric acid solution at a temperature of 70 to 90° C. for 23 to 27 hours, and then filtering, rinsing, vacuum drying, and sieving in sequence; Step S5: cold isostatic pressing, degassing, hot isostatic pressing and pickling are performed on the mixed and sieved beryllium powder in sequence to obtain a beryllium blank.

2. The sustainable beryllium waste recycling and utilization method according to claim 1, characterized in that: In the step S1, the beryllium waste includes beryllium processing chips and beryllium slag; The beryllium slag is crushed unqualified waste beryllium and leftover beryllium materials.

3. The sustainable beryllium waste recycling and utilization method according to claim 2, characterized in that: In the step S2, the degreasing medium in the ultrasonic cleaning is CT-206B weak alkaline degreasing agent; The ultrasonic cleaning time is 45 to 55 minutes.

4. The sustainable beryllium waste recycling and utilization method according to claim 3, characterized in that: In step S2, the vacuum degree of the vacuum drying is 2×10 -2 ~6×10 -2 Pa, the vacuum drying temperature is 110-130°C, and the vacuum drying time is 12-15h.

5. The sustainable beryllium waste recycling and utilization method according to any one of claims 1 to 4, characterized in that: In step S3, the purity of the nitrogen gas impacted by the airflow is greater than 99.1%, and the pressure is 0.9-1.1 MPa.

6. The sustainable beryllium waste recycling and utilization method according to claim 5, characterized in that: In step S4, the nitric acid solution includes concentrated nitric acid with a concentration of 65-71% and water; The volume ratio of the concentrated nitric acid to water is 1.5-1.9:15-19.

7. The sustainable beryllium waste recycling and utilization method according to claim 6, characterized in that: In step S4, the filtration pressure is 1×10 4 ~4×10 4 Pa, temperature is 20-30℃, time is 1-3h; In the step S4, the flushing medium is water; In step S4, the vacuum degree of the vacuum drying is 2×10 -2 ~6×10 -2 Pa, temperature is 80-90℃, time is 20-25h; In step S4, a double sieve of 280-300 mesh and 220-240 mesh is used for mixed screening.

8. The sustainable beryllium waste recycling and utilization method according to claim 7, characterized in that: In step S5, the purity of the mixed beryllium powder after sieving is ≥98.6%.

9. The sustainable beryllium waste recycling and utilization method according to claim 8, characterized in that: In step S5, the cold isostatic pressing pressure is 190-220 MPa and the time is 15-19 minutes; In step S5, the degassing temperature is 650-700° C. and the degassing time is 8-10 hours; In step S5, the hot isostatic pressing pressure is 110-120 MPa, the temperature is 1040-1080° C., and the time is 6-8 hours; In step S5, pickling is performed using a nitric acid solution with a mass concentration of 25-35%.

10. The sustainable beryllium waste recycling and utilization method according to claim 9, characterized in that: In step S5, the beryllium blank has a tensile strength of ≥495 MPa, a yield strength of ≥450 MPa, an elastic modulus of ≥291000 MPa, an elongation of ≥1.8%, and a hardness HRB of ≥90.