A method for producing tantalum strip

Abstract

This application provides a method for producing tantalum bars, utilizing graphite reduction of tantalum oxide in two separate additions. After the first addition of tantalum oxide, it undergoes high-temperature reduction in a graphite resistance furnace to obtain tantalum carbide, the product of the tantalum oxide reaction. The mass of tantalum carbide obtained after the first carbonization is used to calculate the mass of tantalum oxide required for the second addition using a batching formula. This mixture is then combined with the material from the first carbonization, shaped, and sintered in a high-temperature reduction furnace using a stepped-heating method to obtain tantalum bars. This application utilizes a batching formula to accurately calculate the mass of tantalum oxide added twice in the carbon reduction method, solving the problem of inaccurate control of the tantalum oxide content in the second addition.

Description

Technical Field

[0001] This application relates to the field of materials, and mainly to a method for producing tantalum bars. Background Technology

[0002] Tantalum bars, as a high-temperature alloy additive, are an indispensable element in the master alloys of steelmaking enterprises and alloy material manufacturers for further processing, possessing advantages such as high temperature resistance and corrosion resistance. The carbon reduction method for producing tantalum bars refers to the process of using graphite or carbon black as a reducing agent, employing a graphite carbonization furnace and a high-temperature reduction furnace to gradually reduce tantalum pentoxide to tantalum carbide. The tantalum reduction powder is then pressed, molded, and finally fired into tantalum bars.

[0003] The carbon reduction process for producing tantalum bars requires two sintering processes. Before the second sintering begins, a certain amount of tantalum oxide is added based on the results of the first sintering. Summary of the Invention

[0004] To address the challenge of accurately controlling the tantalum oxide content during secondary feeding, this application provides a method for producing tantalum bars. The method includes:

[0005] Tantalum oxide and graphite were added to a V-type mixer and mixed for 6 hours to obtain a preliminary mixture.

[0006] The initial mixed material is added to a graphite resistance furnace and kept at a high temperature for 40-60 minutes. Heating is stopped when the initial mixed material turns into yellow lumps to obtain the first sintered material.

[0007] The primary sintering material is ground, analyzed, and mixed to obtain the Ct value of the primary sintering material tantalum carbide. The mass of secondary tantalum oxide is calculated using the batching formula. The primary sintering material and the secondary tantalum oxide are mixed in a V-type mixer for 8 hours to obtain the secondary tantalum material.

[0008] The binder is mixed into the secondary feed material, and the mixture is then added to a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered.

[0009] The tantalum strip to be sintered is placed on a graphite plate in a high-temperature reduction furnace and sintered by step heating to obtain the tantalum strip.

[0010] Tantalum oxide is reduced using graphite, with the tantalum oxide being added in two stages. The first addition of tantalum oxide is followed by sintering in a 110kW graphite resistance furnace. The material must be thoroughly sintered, resulting in a yellow, lumpy appearance. If incomplete sintering is detected, the process must be repeated. For the second addition, the condition from the first sintering is substituted into the batching formula to determine the required mass of tantalum oxide for the second addition, thus resolving the issue of accurately controlling the tantalum oxide content in the second addition.

[0011] Optionally, the mass of graphite in the primary mixture is 15.5 to 16.0% of the mass of tantalum oxide in the primary mixture.

[0012] Optionally, the purity of the tantalum oxide is greater than or equal to 99.6%.

[0013] Optionally, the graphite has a particle size of less than or equal to 200 mesh and a purity of greater than or equal to 92%.

[0014] Optionally, the graphite resistance furnace has a current of 4500-4600A and a voltage of 16-17V.

[0015] Optionally, the abrasive includes:

[0016] The sintered material is added to a vibratory grinding mill and, after being vibrated and ground, is sieved through the outer screen of the vibratory grinding mill to obtain the sintered material.

[0017] Optionally, the ingredient formula is calculated as follows:

[0018] A*K*m*Ct*100 / 99.6=M;

[0019] Where A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide.

[0020] Optionally, the adhesive is shellac, which is dissolved in alcohol.

[0021] Optionally, the stepped heating sintering of the high-temperature reduction furnace specifically includes:

[0022] The temperature was raised from room temperature to 1350℃ in 1 hour, and then kept at 1350℃ for 3 hours.

[0023] The temperature was raised from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours.

[0024] The temperature is raised from 1700℃ to 1900℃ in 1 hour, and then kept at 1900℃ for 15-20 hours.

[0025] Optionally, the pressure rise rate before shutdown of the high-temperature reduction furnace during stepped heating and sintering is less than or equal to 2 Pa / 5 min.

[0026] This application utilizes graphite to reduce tantalum oxide, adding the tantalum oxide in two stages. After the first addition of tantalum oxide, it undergoes high-temperature reduction in a graphite resistance furnace to obtain tantalum carbide, the product of the tantalum oxide reaction. Based on the tantalum carbide obtained after the first carbonization, the mass of tantalum oxide required for the second addition is calculated according to the batching formula. This mixture is then combined with the material from the first carbonization, shaped, and placed in a high-temperature reduction furnace for stepped-heat sintering to obtain tantalum bars. This application uses a batching formula to accurately calculate the mass of tantalum oxide added twice in the carbon reduction method, solving the problem of inaccurate control of the tantalum oxide content in the second addition. Attached Figure Description

[0027] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the tantalum bar production process;

[0029] Figure 2 A schematic diagram illustrating the material feeding process in the tantalum bar production method. Detailed Implementation

[0030] The embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described below do not represent all embodiments consistent with this application. They are merely examples of systems and methods consistent with some aspects of this application as detailed in the claims.

[0031] The carbon reduction method for producing tantalum bars refers to the process of gradually reducing tantalum pentoxide to tantalum carbide using graphite or carbon black as a reducing agent in a graphite carbonization furnace and a high-temperature reduction furnace. The tantalum oxide used is produced through hydrometallurgy and has a purity of over 99.6%. Hydrometallurgical production of tantalum oxide inevitably involves fluorine, which volatilizes during the initial sintering of tantalum carbide in the carbonization furnace. The reduction is achieved by calcining tantalum oxide, and the reduced substances are low-melting-point, volatile components. Lower levels of fluorine and the reduction are preferable.

[0032] Ct is an inherent property of tantalum carbide. The theoretical Ct value of tantalum carbide is calculated as: atomic weight of carbon / (atomic weight of tantalum + atomic weight of carbon), i.e., 12 / (181 + 12) = 0.0621. For sample analysis, the total carbon content is determined using high-frequency infrared absorption spectrometry. The sample is burned in a high-frequency induction furnace with oxygen to produce carbon monoxide and carbon dioxide. The carbon monoxide is then converted into carbon dioxide in a catalytic furnace, and the generated carbon dioxide is detected in an infrared cell.

[0033] Example 1:

[0034] 100 kg of tantalum oxide and 15.5 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.6%, and the graphite had a particle size of no more than 200 mesh and a purity of 92%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 40 minutes. Heating was stopped when the preliminary mixture turned into yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0035] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.063, the m value was 97.9, and the K value was 1.0. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M of the secondary tantalum oxide was calculated to be 45.6. The primary sintered material and the secondary tantalum oxide were then mixed in a 250L V-type mixer for 8 hours to obtain the secondary sintered material.

[0036] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 15 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0037] Example 2:

[0038] 100 kg of tantalum oxide and 16 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.7%, and the graphite had a particle size of no more than 200 mesh and a purity of 95%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 60 minutes. Heating was stopped when the preliminary mixture appeared as yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0039] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.063, the m value was 90.9, and the K value was 0.9. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M value of the secondary tantalum oxide was calculated to be 38.12. The primary sintered material and the secondary tantalum oxide were then mixed in a 250-liter V-type mixer for 8 hours to obtain the secondary sintered material.

[0040] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 20 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0041] Example 3:

[0042] 100 kg of tantalum oxide and 15.6 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.7%, and the graphite had a particle size of no more than 200 mesh and a purity of 96%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 5 minutes. Heating was stopped when the preliminary mixture appeared as yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0043] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.065, the m value was 92.7, and the K value was 1.0. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M value of the secondary tantalum oxide was calculated to be 44.5. The primary sintered material and the secondary tantalum oxide were then mixed in a 250L V-type mixer for 8 hours to obtain the secondary sintered material.

[0044] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 17 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0045] Example 4:

[0046] 100 kg of tantalum oxide and 15.8 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.6%, and the graphite had a particle size of no more than 200 mesh and a purity of 94%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 45 minutes. Heating was stopped when the preliminary mixture turned into yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0047] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.065, the m value was 95.5, and the K value was 0.9. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M of the secondary tantalum oxide was calculated to be 41.3. The primary sintered material and the secondary tantalum oxide were then mixed in a 250L V-type mixer for 8 hours to obtain the secondary sintered material.

[0048] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to stepped heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 18 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0049] Example 5:

[0050] 100 kg of tantalum oxide and 16 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.6%, and the graphite had a particle size of no more than 200 mesh and a purity of 92%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 60 minutes. Heating was stopped when the preliminary mixture appeared as yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0051] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.066, the m value was 96.4, and the K value was 0.9. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M of the secondary tantalum oxide was calculated to be 42.4. The primary sintered material and the secondary tantalum oxide were then mixed in a 250-liter V-type mixer for 8 hours to obtain the secondary sintered material.

[0052] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 19 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0053] Example 6:

[0054] 100 kg of tantalum oxide and 15.7 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.6%, and the graphite had a particle size of no more than 200 mesh and a purity of 92%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 55 minutes. Heating was stopped when the preliminary mixture turned into yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0055] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.064, the m value was 93.5, and the K value was 1.1. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M value of the secondary tantalum oxide was calculated to be 48.7. The primary sintered material and the secondary tantalum oxide were then mixed in a 250L V-type mixer for 8 hours to obtain the secondary sintered material.

[0056] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 16 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0057] Example 7:

[0058] 100 kg of tantalum oxide and 15.5 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.6%, and the graphite had a particle size of no more than 200 mesh and a purity of 92%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 40 minutes. Heating was stopped when the preliminary mixture turned into yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0059] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.063, the m value was 96.4, and the K value was 0.9. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M of the secondary tantalum oxide was calculated to be 40.4. The primary sintered material and the secondary tantalum oxide were then mixed in a 250L V-type mixer for 8 hours to obtain the secondary sintered material.

[0060] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 20 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0061] Example 8:

[0062] 100 kg of tantalum oxide and 16 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.6%, and the graphite had a particle size of no more than 200 mesh and a purity of 92%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 60 minutes. Heating was stopped when the preliminary mixture appeared as yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0063] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.065, the m value was 92.7, and the K value was 1.0. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M value of the secondary tantalum oxide was calculated to be 44.6. The primary sintered material and the secondary tantalum oxide were then mixed in a 250-liter V-type mixer for 8 hours to obtain the secondary sintered material.

[0064] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 15 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0065] Example 9:

[0066] 100 kg of tantalum oxide and 15.9 kg of graphite were added to a 250 L V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The tantalum oxide had a purity of 99.6%, and the graphite had a particle size of no more than 200 mesh and a purity of 92%. The preliminary mixture was then added to a 110 kW graphite resistance furnace. The furnace current was adjusted to 4500-4600 A, the voltage to 16-17 V, and the furnace was held at a high temperature for 50 minutes. Heating was stopped when the preliminary mixture appeared as yellow lumps, resulting in the first sintered material. To achieve better sintering results, it is necessary to ensure that the material is thoroughly sintered. If the material is not thoroughly sintered, a second sintering process is required.

[0067] The primary sintered material was added to a vibratory grinding mill and, after vibratory grinding, passed through the outer screen of the mill to obtain the primary sintered material. Analysis revealed that the Ct value of tantalum carbide in the primary sintered material was 0.065, the m value was 95.8, and the K value was 1.0. Using the batching formula A*K*m*Ct*100 / 99.6=M (A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide), the mass M value of the secondary tantalum oxide was calculated to be 46.1. The primary sintered material and the secondary tantalum oxide were then mixed in a 250L V-type mixer for 8 hours to obtain the secondary sintered material.

[0068] Shellac dissolved in alcohol is mixed into the secondary feed material, and the mixture is then fed into a 500t new fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum bars to be sintered are placed on a graphite plate in a high-temperature reduction furnace and subjected to step-by-step heating sintering: the temperature is increased from room temperature to 1350℃ in 1 hour, and then held at 1350℃ for 3 hours; the temperature is increased from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours; the temperature is increased from 1700℃ to 1900℃ in 1 hour, and then held at 1900℃ for 19 hours to obtain tantalum bars. The pressure rise rate before furnace shutdown is no higher than 2Pa / 5min.

[0069] Similar parts between the embodiments provided in this application can be referred to mutually. The specific implementation methods provided above are only a few examples under the overall concept of this application and do not constitute a limitation on the scope of protection of this application. For those skilled in the art, any other implementation methods extended from the solution of this application without creative effort shall fall within the scope of protection of this application.

Claims

1. A method for producing tantalum bars, characterized in that, include: Tantalum oxide and graphite were added to a V-type mixer and mixed for 6 hours to obtain a preliminary mixture. The initial mixed material is added to a graphite resistance furnace and kept at a high temperature for 40-60 minutes. Heating is stopped when the initial mixed material turns into yellow lumps to obtain the first sintered material. The graphite resistance furnace has a current of 4500-4600A and a voltage of 16-17V. The primary sintering material was abraded, and the Ct value of tantalum carbide in the primary sintering material was obtained by analysis. The mass of secondary tantalum oxide was calculated using the batching formula. The primary sintering material and the secondary tantalum oxide were mixed in a V-type mixer for 8 hours to obtain the secondary tantalum material. Ct is an inherent property of tantalum carbide. The theoretical value of Ct for tantalum carbide is calculated as: atomic weight of carbon / (atomic weight of tantalum + atomic weight of carbon), i.e., 12 / (181 + 12) = 0.0621. The ingredient formula is calculated as follows: A*K*m*Ct*100 / 99.6=M; Where A is a constant of 7.367, K represents the peroxide coefficient, m represents the weight of tantalum carbide, and M represents the weight of tantalum oxide; The binder is mixed into the secondary feed material, and the mixture is then added to a 500t fully automatic hydraulic press for molding to obtain tantalum bars to be sintered. The tantalum strip to be sintered is placed on a graphite plate in a high-temperature reduction furnace and sintered by step heating to obtain the tantalum strip.

2. The method for producing tantalum bars according to claim 1, characterized in that, The mass of graphite in the primary mixture is 15.5 to 16.0% of the mass of tantalum oxide in the primary mixture.

3. The method for producing tantalum bars according to claim 1, characterized in that, The purity of the tantalum oxide is greater than or equal to 99.6%.

4. The method for producing tantalum bars according to claim 1, characterized in that, The graphite has a particle size of less than or equal to 200 mesh and a purity of greater than or equal to 92%.

5. The method for producing tantalum bars according to claim 1, characterized in that, The abrasive includes: The sintered material is added to a vibratory grinding mill and, after being vibrated and ground, is sieved through the outer screen of the vibratory grinding mill to obtain the sintered material.

6. The method for producing tantalum bars according to claim 1, characterized in that, The adhesive is shellac, which is dissolved in alcohol.

7. The method for producing tantalum bars according to claim 1, characterized in that, The stepped heating sintering of the high-temperature reduction furnace specifically includes: The temperature was raised from room temperature to 1350℃ in 1 hour, and then kept at 1350℃ for 3 hours. The temperature was raised from 1350℃ to 1700℃ in 1 hour, and then held at 1700℃ for 3 hours. The temperature is raised from 1700℃ to 1900℃ in 1 hour, and then kept at 1900℃ for 15-20 hours.

8. The method for producing tantalum bars according to claim 7, characterized in that, The pressure rise rate before shutdown of the stepped heating sintering furnace in the high-temperature reduction furnace is less than or equal to 2 Pa / 5 min.

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