Method for preparing beryllium copper master alloy from beryllium cloth bag powder waste

Abstract

The invention discloses a method for preparing beryllium-copper master alloy from beryllium cloth bag powder waste, and belongs to the technical field of metal materials, the method comprises the following steps: filling the beryllium cloth bag powder waste, pure copper powder, a grinding aid and zirconium oxide balls into a bin body of a horizontal stirring ball mill, and then carrying out ball milling under the protection of inert gas to obtain beryllium-copper mixed powder; the beryllium-copper mixed powder is loaded into a cold pressing mold to be subjected to cold pressing forming, and a beryllium-copper round cake is obtained; burdening the beryllium copper round cake and electrolytic copper according to the beryllium and copper contents in the beryllium copper mother alloy, filling a crucible of a vacuum suspension smelting furnace, and carrying out vacuum suspension smelting under the protection of strong cold circulating water to obtain beryllium copper alloy liquid; and then turning over the crucible, casting the beryllium copper alloy liquid into the mold in vacuum, cooling to a certain temperature, opening the furnace, and air-cooling to the room temperature. The beryllium copper master alloy is uniform in component, few in impurity element, high in purity and low in oxygen content, the technological process is short, energy consumption is low, and high-value utilization of beryllium cloth bag powder is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal materials, and in particular relates to a method for preparing a beryllium copper master alloy by using waste beryllium cloth bag powder. Background Art

[0002] Metallic beryllium has a lower density, higher specific stiffness and lower thermal expansion coefficient than other metals, and has broad application prospects in aerospace and high-end materials. A large amount of waste beryllium bag powder is generated during the preparation of beryllium materials. After testing and analyzing it, it was found that the beryllium content in the bag powder is high and the recycling value is large. Due to the small particle size and high toxicity of the bag powder, it is difficult to recycle, and there is currently no process technology solution with excellent recycling effect.

[0003] Beryllium copper alloy is the most widely used alloy in the beryllium alloy series. It combines the high stiffness, low density, high thermal stability of beryllium with the high toughness and high conductivity of copper, making it have excellent strength, hardness, electrical conductivity, corrosion resistance, wear resistance and good thermal conductivity. It has great application prospects in aerospace, marine engineering, petrochemical and other fields. Beryllium copper master alloy is one of the key raw materials for the production of beryllium bronze materials. The impurity content of its raw materials greatly affects the quality of beryllium bronze products. How to use beryllium bag powder to prepare high-purity beryllium copper master alloy is a difficult problem that needs to be solved to achieve high-value utilization of beryllium bag powder waste.

[0004] The Chinese patent with application number 202111110328.5 discloses a "method for preparing a master alloy for beryllium bronze based on electroslag smelting of beryllium bag powder waste". First, the beryllium bag powder waste is mixed with water, isostatically pressed into a rod shape and then dried. Then, pure copper is heated and melted to obtain molten copper. Multiple beryllium rods are cast into a T-shaped hollow graphite mold for demolding to obtain a consumable electrode for electroslag remelting. Finally, a beryllium copper master alloy ingot is prepared by adjusting the electroslag remelting process parameters. However, there are the following shortcomings: the target beryllium content of the beryllium copper master alloy is difficult to control, and the beryllium content is restricted by the beryllium copper sandwich electrode formed by the casting of the beryllium rod and the copper liquid, and the composition is difficult to control. In addition, the beryllium copper sandwich electrode is formed by inserting multiple beryllium coppers into the copper liquid in sequence during the casting process. The discontinuous distribution of the beryllium rods affects the beryllium composition in the beryllium copper master alloy. At the same time, the beryllium copper sandwich electrode is exposed to air during the casting process, which will increase the oxygen content in the beryllium copper master alloy and increase the number of inclusions. The recycling process of the beryllium bag powder waste is complicated.

[0005] Currently, there is no simple and efficient method for processing beryllium bag powder waste. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing a beryllium copper master alloy by using waste beryllium bag powder. The method can quickly obtain a beryllium copper master alloy with uniform composition, few impurity elements, high purity and low oxygen content, and the process flow is relatively short and the energy consumption is low, thereby realizing the high-value utilization of beryllium bag powder.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing beryllium copper master alloy using beryllium bag powder waste, the method comprising:

[0009] Step S1, after loading beryllium bag powder waste, pure copper powder, grinding aid and zirconium oxide balls into a horizontal stirring ball mill, ball milling is performed under the protection of inert gas to obtain beryllium copper mixed powder;

[0010] In the step S1, the mass ratio of the beryllium bag powder to the pure copper powder is 20-40:60-80;

[0011] The grinding aid is 0.5-2.0% of the total mass of the beryllium bag powder and the pure copper powder;

[0012] Step S2, placing the beryllium copper mixed powder into a cold pressing mold, maintaining the pressure at a pressure of 260 to 350 MPa for 5 to 15 minutes, to obtain a beryllium copper round cake;

[0013] Step S3, the beryllium copper round cake and the electrolytic copper are mixed according to the beryllium and copper contents in the beryllium copper master alloy, and are loaded into a crucible of a vacuum suspension smelting furnace, and vacuum suspension smelting is performed under the protection of strong cooling circulating water to obtain a beryllium copper alloy liquid; then the crucible is turned over, and the beryllium copper alloy liquid is vacuum cast into a mold, and after cooling to 80-120° C., the furnace is opened and air-cooled to room temperature to obtain a beryllium copper master alloy ingot.

[0014] Furthermore, in the step S1, the ball-to-material ratio of the ball mill is 10 to 30:1.

[0015] Furthermore, in the step S1, the process parameters of the ball milling are: the stirring shaft speed is 500 to 1200 rpm, and the ball milling time is 1 to 4 hours.

[0016] Furthermore, in the step S1, the median particle size of the beryllium bag powder waste is less than or equal to 20 microns, and the purity is greater than or equal to 95%;

[0017] The median particle size of the pure copper powder is less than or equal to 75 microns, and the purity is greater than or equal to 99.8%.

[0018] Further, in the step S1, the median particle size of the beryllium bag powder waste is 12 to 15 microns, and the purity is 97.5 to 98.5%;

[0019] The median particle size of the pure copper powder is 68 to 72 microns.

[0020] Furthermore, in step S1, the grinding aid is one or a mixture of two or more of stearic acid, anhydrous ethanol and polyethylene glycol.

[0021] Furthermore, in step S3, the inlet temperature of the strong cooling circulating water is 15-17°C, the outlet temperature is 20-23°C, and the temperature difference between the outlet temperature and the inlet temperature is 4-6°C.

[0022] Furthermore, in step S3, the specific process of the vacuum suspension smelting includes:

[0023] The vacuum degree in the vacuum suspension melting furnace is 4.3~5.2×10 -3 Pa, then fill with argon until the pressure in the vacuum suspension melting furnace is 38-42 kPa, then increase the melting power to 120-160 kW at a rate of 42-58 kW / min until the temperature reaches 1060-1080°C, and melt for 4-10 minutes;

[0024] Continue to increase the smelting power to 200-240 kW at a rate of 42-58 kW / min until the temperature reaches 1100-1250°C, and perform suspension refining for 10-20 minutes.

[0025] Furthermore, in step S3, the turning angle of the crucible is 120-135°.

[0026] Furthermore, in step S3, the mold is made of stainless steel.

[0027] In summary, the technical solution of the present invention has the following technical effects:

[0028] The invention uses waste beryllium bag powder as raw material, adopts mechanical ball milling to mix waste beryllium bag powder and pure copper powder to form beryllium copper mixed powder, and then obtains beryllium copper round cakes through cold pressing, thereby reducing the difficulty of pressing and molding waste beryllium bag powder; through the beryllium content in beryllium copper master alloy, beryllium copper round cakes and electrolytic copper are added, and beryllium copper master alloy ingots are obtained through vacuum suspension smelting and vacuum casting, thereby realizing high-value resource recycling of waste beryllium bag powder; the invention adopts vacuum suspension smelting and vacuum casting, thereby inhibiting grain growth and forming fine-grained structure; in addition, the vacuum suspension smelting and vacuum casting of the invention are both carried out under the protection of strong cold circulating water, thereby avoiding beryllium segregation to a great extent, ensuring the uniformity of beryllium content in beryllium copper master alloy ingots, reducing the impurity content of beryllium copper master alloy ingots, and can be used as an intermediate alloy to prepare high-beryllium copper and low-beryllium copper alloys. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] This embodiment provides a method for preparing beryllium copper master alloy using beryllium bag powder waste, the method comprising:

[0031] Step S1: After the waste beryllium bag powder, pure copper powder, grinding aid and zirconium oxide balls are loaded into a horizontal stirring ball mill, ball milling is performed under the protection of inert gas to obtain beryllium copper mixed powder.

[0032] In this embodiment, waste beryllium bag powder and pure copper powder are added to the chamber of a horizontal high-energy stirring ball mill, and zirconium oxide balls are added. By replacing the gas in the chamber, the ball milling is ensured to be carried out under the protection of an inert gas (such as argon gas) during the experiment to obtain a beryllium copper mixed powder.

[0033] The median particle size of the waste beryllium bag powder in this embodiment is less than or equal to 20 microns, preferably 12-15 microns, and the purity is greater than or equal to 95%, preferably 97.5-98.5%. The median particle size of the pure copper powder is less than or equal to 75 microns, preferably 68-72 microns, and the purity is greater than or equal to 99.8%.

[0034] The mass ratio of beryllium bag powder and pure copper powder in this embodiment is 20-40:60-80, the grinding aid is 0.5-2.0% of the total mass of the beryllium bag powder and pure copper powder, and the grinding aid is one or a mixture of two or more of stearic acid, anhydrous ethanol and polyethylene glycol. The ball-to-material ratio of ball milling is 10-30:1, that is, the mass ratio of zirconium oxide balls to the total mass of beryllium bag powder waste, pure copper powder and grinding aid is 10-30:1.

[0035] The process parameters of the ball milling in this embodiment are: the stirring shaft speed is 500-1200 rpm, and the ball milling time is 1-4 hours.

[0036] Step S2, placing the beryllium copper mixed powder into a cold pressing mold, maintaining the pressure at a pressure of 260 to 350 MPa for 5 to 15 minutes, and obtaining a beryllium copper round cake.

[0037] By placing the beryllium copper mixed powder into a cold pressing mold and selecting a suitable molding pressure and holding pressure (ie cold pressing) time, a plurality of beryllium copper round cakes are obtained. The inner diameter of the cold pressing mold in this embodiment is Φ60 mm.

[0038] Step S3, the beryllium copper round cake and the electrolytic copper are mixed according to the beryllium and copper contents in the beryllium copper master alloy, and are loaded into a crucible of a vacuum suspension smelting furnace, and vacuum suspension smelting is performed under the protection of strong cooling circulating water to obtain a beryllium copper alloy liquid; then the crucible is turned over 120-135 degrees, and the beryllium copper alloy liquid is vacuum cast into a stainless steel mold, and after cooling to 80-120° C., the furnace is opened and air-cooled to room temperature to obtain a beryllium copper master alloy ingot.

[0039] The vacuum suspension melting and vacuum casting in this embodiment are both carried out under the protection of strong cooling circulating water, the inlet temperature of the strong cooling circulating water is 15-17°C, the outlet temperature is 20-23°C, and the temperature difference between the outlet temperature and the inlet temperature is 4-6°C.

[0040] The specific process of vacuum suspension melting in this embodiment includes:

[0041] The vacuum degree in the vacuum suspension melting furnace is 4.3~5.2×10 -3 Pa, then fill with argon until the pressure in the vacuum suspension melting furnace is 38-42 kPa, then increase the melting power to 120-160 kW at a rate of 42-58 kW / min until the temperature reaches 1060-1080°C, and melt for 4-10 minutes;

[0042] Continue to increase the smelting power to 200-240 kW at a rate of 42-58 kW / min until the temperature reaches 1100-1250°C, and carry out suspension refining for 10-20 minutes (i.e. observe the suspension state of the molten metal in the crucible through the observation window, start timing when a "small peak" appears, and complete the refining after maintaining it for 10-20 minutes).

[0043] This embodiment adopts vacuum suspension melting and vacuum casting to prepare beryllium copper master alloy. Its high melting temperature rise rate and short melting cycle can further inhibit grain growth and form fine-grained structure.

[0044] The inner diameter of the crucible in this embodiment is Φ80mm×240mm. The inner diameter of the stainless steel mold is Φ100mm~Φ150mm.

[0045] Embodiment 1:

[0046] Step S1, beryllium bag powder waste with a median particle size of 15 microns and a purity of 97.5%, pure copper powder with a median particle size of 72 microns and a purity of 99.8%, and stearic acid are loaded into the bin of a horizontal high-energy stirring ball mill, and then zirconium oxide balls are added according to a ball-to-material ratio of 10:1, and the air in the bin is replaced by a vacuum pump and argon gas, so that the atmosphere in the bin is argon gas, and then the stirring shaft is rotated at 800 rpm for 2 hours to obtain a beryllium copper mixed powder.

[0047] The mass ratio of the beryllium bag powder to the pure copper powder is 20:80, and the mass of the stearic acid is 1.5% of the total mass of the beryllium bag powder and the pure copper powder.

[0048] Step S2, placing the beryllium copper mixed powder into a cold pressing mold, maintaining the pressure at a pressure of 350 MPa for 5 minutes, and obtaining a beryllium copper round cake.

[0049] Step S3: The beryllium copper round cake and electrolytic copper are mixed according to the beryllium content of 9.98wt% in the beryllium copper master alloy and loaded into the crucible of the vacuum suspension melting furnace. The automatic vacuum system is turned on, and the vacuum gauge is turned on, and the vacuum degree in the suspension melting furnace is waited to reach 5.2×10 -3 Pa or less. Turn off the vacuum gauge, turn off the automatic vacuum system, open the argon filling valve, and when the argon pressure in the furnace reaches 40kPa, close the argon filling valve. Turn on the smelting control system, and under the protection of strong cold circulating water, gradually increase the smelting power to 120kW at a rate of 42kW / min until the temperature reaches 1060℃, and smelt for 10 minutes. Increase the smelting power to 220kW at a rate of 42kW / min, so that the smelting temperature reaches 1180℃; observe the suspension morphology of the molten metal in the crucible through the observation window, start timing when a "small peak" appears, and complete the refining after 10 minutes. Turn off the smelting control system, turn the crucible 130°, and vacuum cast the beryllium copper alloy liquid into a stainless steel mold with an inner diameter of Φ100mm through a funnel. After cooling to 100℃, open the furnace and air cool to room temperature to obtain a beryllium copper master alloy ingot.

[0050] The inlet temperature of the forced cooling circulating water in this embodiment is 16°C, the outlet temperature is 20°C, and the temperature difference between the outlet temperature and the inlet temperature is 4°C.

[0051] The drilling samples were tested by ICP spectrometer, and the test results of the beryllium copper master alloy ingot of this implementation are as follows:

[0052] Be: 9.81wt%, Ni: 0.15wt%, Co: 0.035wt%, Al: 0.055wt%, Si: 0.065wt%, Pb: <0.0020wt%, Fe: 0.080wt%.

[0053] Embodiment 2:

[0054] Step S1, beryllium bag powder waste with a median particle size of 12 microns and a purity of 98.5%, pure copper powder with a median particle size of 68 microns and a purity of 99.85%, stearic acid, and polyethylene glycol are loaded into the bin of a horizontal high-energy stirring ball mill, and then zirconium oxide balls are added according to a ball-to-material ratio of 30:1, and the air in the bin is replaced by a vacuum pump and argon gas, so that the atmosphere in the bin is argon gas, and then the stirring shaft is rotated at 1200 rpm for 1 hour to obtain a beryllium copper mixed powder.

[0055] The mass ratio of the beryllium bag powder to the pure copper powder is 40:60, and the sum of the mass of stearic acid and polyethylene glycol is 0.5% of the total mass of the beryllium bag powder and the pure copper powder.

[0056] Step S2, placing the beryllium copper mixed powder into a cold pressing mold, maintaining the pressure at a pressure of 260 MPa for 15 minutes, and obtaining a beryllium copper round cake.

[0057] Step S3: Beryllium copper round cakes and electrolytic copper are mixed according to the beryllium content of 10.12wt% in the beryllium copper master alloy, and loaded into the crucible of the vacuum suspension melting furnace. Turn on the automatic vacuum system, turn on the vacuum gauge, and wait for the vacuum degree in the suspension melting furnace to reach 4.3×10 -3 Pa or less. Turn off the vacuum gauge, turn off the automatic vacuum system, open the argon filling valve, and when the argon pressure in the furnace reaches 38kPa, close the argon filling valve. Turn on the smelting control system, and under the protection of strong cold circulating water, gradually increase the smelting power to 160kW at a rate of 58kW / min until the temperature reaches 1080℃ and smelt for 6 minutes. Increase the smelting power to 240kW at a rate of 58kW / min, so that the smelting temperature reaches 1250℃; observe the suspension morphology of the molten metal in the crucible through the observation window, start timing when a "small peak" appears, and complete the refining after 15 minutes. Turn off the smelting control system, turn the crucible 120°, and vacuum cast the beryllium copper alloy liquid into a stainless steel mold with an inner diameter of Φ100mm through a funnel. After cooling to 120℃, open the furnace and air cool to room temperature to obtain a beryllium copper master alloy ingot.

[0058] The inlet temperature of the forced cooling circulating water in this embodiment is 17°C, the outlet temperature is 23°C, and the temperature difference between the outlet temperature and the inlet temperature is 6°C.

[0059] The drilling samples were tested by ICP spectrometer, and the test results of the beryllium copper master alloy ingot of this implementation are as follows:

[0060] Be: 10.06wt%, Ni: 0.17wt%, Co: 0.026wt%, Al: 0.051wt%, Si: 0.063wt%, Pb: <0.0020wt%, Fe: 0.073wt%.

[0061] Embodiment 3:

[0062] Step S1, beryllium bag powder waste with a median particle size of 20 microns and a purity of 95%, pure copper powder with a median particle size of 75 microns and a purity of 99.8%, and polyethylene glycol are loaded into the bin of a horizontal high-energy stirring ball mill, and then zirconium oxide balls are added according to a ball-to-material ratio of 20:1, and the air in the bin is replaced by a vacuum pump and argon gas, so that the atmosphere in the bin is argon gas, and then the stirring shaft is rotated at 500 rpm for 4 hours to obtain a beryllium copper mixed powder.

[0063] The mass ratio of the beryllium bag powder to the pure copper powder is 30:70, and the polyethylene glycol accounts for 2.0% of the total mass of the beryllium bag powder and the pure copper powder.

[0064] Step S2, placing the beryllium copper mixed powder into a cold pressing mold, maintaining the pressure at 300 MPa for 10 minutes, and obtaining a beryllium copper round cake.

[0065] Step S3: The beryllium copper round cake and electrolytic copper are mixed according to the beryllium content of 9.76wt% in the beryllium copper master alloy and loaded into the crucible of the vacuum suspension melting furnace. The automatic vacuum system is turned on, and the vacuum gauge is turned on, and the vacuum degree in the suspension melting furnace is waited to reach 5.0×10 -3 Pa or less. Turn off the vacuum gauge, turn off the automatic vacuum system, open the argon filling valve, and when the argon pressure in the furnace reaches 42kPa, close the argon filling valve. Turn on the smelting control system, and under the protection of strong cold circulating water, gradually increase the smelting power to 140kW at a rate of 55kW / min until the temperature reaches 1060℃, and smelt for 4 minutes. Increase the smelting power to 200kW at a rate of 55kW / min, so that the smelting temperature reaches 1100℃; observe the suspension morphology of the molten metal in the crucible through the observation window, start timing when a "small peak" appears, and complete the refining after 20 minutes. Turn off the smelting control system, turn the crucible 135°, and vacuum cast the beryllium copper alloy liquid into a stainless steel mold with an inner diameter of Φ100mm through a funnel. After cooling to 80℃, open the furnace and air cool to room temperature to obtain a beryllium copper master alloy ingot.

[0066] The inlet temperature of the forced cooling circulating water in this embodiment is 15°C, the outlet temperature is 20°C, and the temperature difference between the outlet temperature and the inlet temperature is 5°C.

[0067] The drilling samples were tested by ICP spectrometer, and the test results of the beryllium copper master alloy ingot of this implementation are as follows:

[0068] Be: 9.72wt%, Ni: 0.15wt%, Co: 0.020wt%, Al: 0.054wt%, Si: 0.065wt%, Pb: <0.0020wt%, Fe: 0.069wt%.

[0069] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for preparing beryllium copper master alloy using beryllium bag powder waste, characterized in that: The method comprises: Step S1, after loading beryllium bag powder waste, pure copper powder, grinding aid and zirconium oxide balls into a horizontal stirring ball mill, ball milling is performed under the protection of inert gas to obtain beryllium copper mixed powder; In the step S1, the mass ratio of the beryllium bag powder to the pure copper powder is 20-40:60-80; The grinding aid is 0.5-2.0% of the total mass of the beryllium bag powder and the pure copper powder; Step S2, placing the beryllium copper mixed powder into a cold pressing mold, maintaining the pressure at a pressure of 260 to 350 MPa for 5 to 15 minutes, to obtain a beryllium copper round cake; Step S3, the beryllium copper round cake and the electrolytic copper are mixed according to the beryllium and copper contents in the beryllium copper master alloy, and are loaded into a crucible of a vacuum suspension smelting furnace, and vacuum suspension smelting is performed under the protection of strong cooling circulating water to obtain a beryllium copper alloy liquid; then the crucible is turned over, and the beryllium copper alloy liquid is vacuum cast into a mold, and after cooling to 80-120° C., the furnace is opened and air-cooled to room temperature to obtain a beryllium copper master alloy ingot.

2. The method according to claim 1, characterized in that In the step S1, the ball-to-material ratio of the ball mill is 10 to 30:

1.

3. The method according to claim 2, characterized in that In the step S1, the process parameters of the ball milling are: the stirring shaft speed is 500 to 1200 rpm, and the ball milling time is 1 to 4 hours.

4. The method according to claim 3, characterized in that In the step S1, the median particle size of the beryllium bag powder waste is less than or equal to 20 microns, and the purity is greater than or equal to 95%; The median particle size of the pure copper powder is less than or equal to 75 microns, and the purity is greater than or equal to 99.8%.

5. The method according to claim 4, characterized in that In the step S1, the median particle size of the beryllium bag powder waste is 12 to 15 microns, and the purity is 97.5 to 98.5%; The median particle size of the pure copper powder is 68 to 72 microns.

6. The method according to claim 5, characterized in that In the step S1, the grinding aid is one or a mixture of two or more of stearic acid, anhydrous ethanol and polyethylene glycol.

7. The method according to any one of claims 1 to 6, characterized in that: In step S3, the inlet temperature of the strong cooling circulating water is 15-17°C, the outlet temperature is 20-23°C, and the temperature difference between the outlet temperature and the inlet temperature is 4-6°C.

8. The method according to claim 7, characterized in that In step S3, the specific process of the vacuum suspension smelting includes: The vacuum degree in the vacuum suspension melting furnace is 4.3~5.2×10 -3 Pa, then fill with argon until the pressure in the vacuum suspension melting furnace is 38-42 kPa, then increase the melting power to 120-160 kW at a rate of 42-58 kW / min until the temperature reaches 1060-1080°C, and melt for 4-10 minutes; Continue to increase the smelting power to 200-240 kW at a rate of 42-58 kW / min until the temperature reaches 1100-1250°C, and perform suspension refining for 10-20 minutes.

9. The method according to claim 8, characterized in that In the step S3, the turning angle of the crucible is 120-135°.

10. The method according to claim 9, characterized in that In step S3, the mold is made of stainless steel.