A method for deoxidizing a carbon fiber web in an AuCuNi alloy melt

Abstract

The present application relates to a kind of carbon fiber web deoxidation method of AuCuNi alloy melt, belong to precious metal refining field.The present application includes the following steps: S1: AuCuNi alloy is placed into graphite crucible;S2: argon is passed;S3: adjust telescopic ceramic transmission shaft elongation drive carbon fiber deoxidation net immerse into alloy melt and start deoxidation;S4: adjust telescopic ceramic transmission shaft shortening drive carbon fiber deoxidation net and separate from alloy melt, stop deoxidation, and obtain finished deoxidation AuCuNi alloy ingot after cooling.The present application is simple in structure by device, and reduction reaction is carried out between carbon fiber deoxidation net and oxide in AuCuNi alloy melt, so that simple operation is realized, and effective and fast deoxidation is realized, which is beneficial to reduce deoxidation cost and deoxidation difficulty.

Description

Technical Field

[0001] This invention belongs to the field of precious metal refining and relates to a method for deoxidizing AuCuNi alloy melt using carbon fiber mesh. Background Technology

[0002] Gold-copper-nickel alloys, with their excellent chemical stability, resistance to arc erosion, and low contact resistance, are ideal electrical contact materials in low contact pressure and low current environments. However, during the alloy smelting process, gold, due to its high stability, is generally not easily oxidized, while copper and nickel readily react with oxygen to form Cu₂O and NiO oxides, thus affecting the alloy's performance and service life. Therefore, deoxidation of the alloy melt is necessary during the alloy smelting process to reduce or eliminate the impact of oxides on the alloy's performance and service life.

[0003] Currently, vacuum deoxidation is the main method for processing gold-copper-nickel alloys. However, this method is not only energy-intensive and difficult to operate, but also has extremely strict requirements for equipment sealing and the vacuum system, resulting in relatively high costs.

[0004] Therefore, it is necessary to provide a carbon fiber mesh deoxidation method for AuCuNi alloy melt, which simplifies the deoxidation operation of AuCuNi alloy melt, reduces equipment requirements, and thus reduces costs. Summary of the Invention

[0005] To overcome the problems in the prior art, this invention proposes a carbon fiber mesh deoxidation method for AuCuNi alloy melt. By utilizing the carbon fiber deoxidation mesh to undergo a reduction reaction with Cu2O and NiO dissolved in the melt, deoxidation is achieved. This simplifies the deoxidation operation, reduces equipment requirements, lowers deoxidation costs, and increases the contact area between the carbon fiber deoxidation mesh and the AuCuNi alloy melt through the mesh structure, thereby improving the deoxidation speed.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] The deoxygenation method includes the following steps:

[0008] S1: Place the AuCuNi alloy into a graphite crucible 4, which is then placed in a 310S stainless steel reduction vessel 6, which is placed inside an electric resistance furnace 1.

[0009] S2: Open the argon valve, adjust the argon flow rate, and introduce argon into the 310S stainless steel reduction tank 6 through the ceramic inlet pipe 9 set on the side wall of the 310S stainless steel reduction tank 6.

[0010] S3: Turn on the resistance furnace 1 to heat the AuCuNi alloy, melting it into an AuCuNi alloy melt. Adjust the extension of the telescopic ceramic drive shaft 10 to move the connected carbon fiber deoxidizing mesh 5 downwards and immerse it in the AuCuNi alloy melt, starting the deoxidation treatment of the AuCuNi alloy melt. The CO and CO2 generated during the process are discharged through the ceramic exhaust pipe 11 set on the side wall of the 310S stainless steel reduction tank 6. The carbon fiber deoxidizing mesh 5 is clamped and fixed by the carbon fiber mesh ceramic support 13. The carbon fiber mesh ceramic support 13 is fixedly connected to one end of the telescopic ceramic drive shaft 10. The other end of the telescopic ceramic drive shaft 10 passes through the 310S stainless steel reduction tank 6 and the furnace cover 2 of the resistance furnace 1 and is hinged to one end of the second connecting rod. The other end of the second connecting rod is hinged to one end of the first connecting rod. The other end of the first connecting rod is fixedly connected to the drive shaft of the reciprocating motor 12. The telescopic ceramic drive shaft 10 is restricted to moving only axially by the guide plate.

[0011] S4: After the reaction in step S3 is completed, adjust the telescopic ceramic drive shaft 10 to shorten it. The telescopic ceramic drive shaft 10 drives the carbon fiber deoxidizing mesh 5 to move upward and separate from the AuCuNi alloy melt. Then, turn off the resistance furnace 1. After the AuCuNi alloy melt solidifies, turn off the argon valve and cool it to obtain a deoxidized AuCuNi alloy ingot.

[0012] Preferably, during the deoxidation process in step S3, the reciprocating motor 12 is turned on, and the carbon fiber deoxidation mesh 5 is moved up and down in the AuCuNi alloy melt by the reciprocating motor 12. After the deoxidation is completed, the reciprocating motor 12 is turned off.

[0013] Preferably, in step S3, the carbon fiber deoxidizing mesh 5 moves up and down in the AuCuNi alloy melt at a speed of 10-20 mm / s, and the deoxidation time is 40-100 min.

[0014] Preferably, the carbon fiber deoxidizing mesh 5 is composed of multiple carbon fiber meshes stacked together, with the area of ​​a single carbon fiber mesh being 80% of the cross-sectional area of ​​the graphite crucible 4, the thickness of a single carbon fiber mesh being 1 mm, the pore density being 30-40 mesh, and the number of stacked layers of the carbon fiber mesh 5 being 3-6 layers.

[0015] Preferably, in the AuCuNi alloy, the mass ratio of pure gold, pure nickel, and pure copper is 80-86:10:4-10.

[0016] Preferably, in step S2, the argon gas flow rate is 0.6–1.5 L / min·cm. 3 .

[0017] Preferably, in step S3, the AuCuNi alloy is heated to 1000°C to obtain an AuCuNi alloy melt.

[0018] Preferably, in step S3, the carbon fiber deoxidizing mesh 5 is driven downward by the telescopic ceramic drive shaft 10 until it stops when the distance between it and the bottom of the graphite crucible 4 is 60mm.

[0019] Preferably, the ceramic intake pipe 9, the ceramic exhaust pipe 11, and the 310S stainless steel reduction tank 6 are sealed by welding, and a dynamic seal 7 is provided between the telescopic ceramic drive shaft 10 and the 310S stainless steel reduction tank 6.

[0020] Preferably, the lid of the 310S stainless steel reduction tank 6 is sealed to the tank body via a flange 8.

[0021] Preferably, a thermocouple 3 is installed at the bottom of the resistance furnace 1 to measure the temperature in the resistance furnace 1.

[0022] The beneficial effects of this invention are:

[0023] 1. This invention utilizes the reduction reaction between carbon fiber deoxidation mesh and Cu2O and NiO in AuCuNi alloy melt to achieve low-cost and simple deoxidation of AuCuNi alloy melt, with good deoxidation effect and low requirements for deoxidation equipment.

[0024] 2. This invention increases the contact area between the carbon fiber deoxidation mesh and the melt through the mesh structure, thereby effectively improving the deoxidation speed.

[0025] 3. In this invention, the carbon fiber deoxidizing mesh moves up and down in the melt during the deoxidation process, creating a disturbance in the melt and giving it a certain flowability. This increases the probability that Cu2O and NiO dissolved in the melt will come into contact with the carbon fiber deoxidizing mesh for deoxidation, thereby further improving the deoxidation effect and deoxidation speed. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the deoxygenation device used in the method of the present invention.

[0027] Figure 2 This is a schematic diagram of the carbon fiber deoxidation mesh and carbon fiber mesh ceramic support structure of the present invention.

[0028] Figure 3 This is a process flow diagram of the present invention.

[0029] In the diagram, 1-resistance furnace, 2-furnace cover, 3-thermocouple, 4-graphite crucible, 5-carbon fiber deoxidation mesh, 6-310S stainless steel reduction tank, 7-dynamic seal, 8-flange, 9-ceramic inlet pipe, 10-telescopic ceramic drive shaft, 11-ceramic exhaust pipe, 12-reciprocating motor, 13-carbon fiber mesh ceramic support. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments.

[0031] The main chemical reaction process of this invention is as follows:

[0032] 2Cu₂O + C → 4Cu + CO₂

[0033] NiO + C → Ni + CO

[0034] AuCuNi alloys have a high oxygen content, with oxygen mainly existing in the form of NiO and Cu2O. After NiO and Cu2O are formed on the surface of the melt, they can continuously dissolve into the melt.

[0035] In carbon fiber deoxidation mesh, carbon undergoes a reduction reaction with Cu2O and NiO to produce Cu, Ni, CO2, and CO. Since CO and CO2 are insoluble in the melt, they escape from the melt, thereby achieving the purpose of deoxidation.

[0036] Thermodynamic calculations were performed on the deoxygenation process, and the results are shown in Table 1.

[0037] Table 1

[0038]

[0039] 2Cu + 0.5O₂ = Cu₂O ①

[0040] C + O₂ = CO₂ ②

[0041] ② - 2 × ① yields 2Cu₂O + C = 4Cu + CO₂

[0042] According to ΔG 0 The Gibbs free energy of the reduction reaction is calculated using the formula A + BT. The calculation shows that when T = 1000℃, ΔG 0 =-204290<0, therefore the reaction can proceed.

[0043] Ni + 0.5O₂ = NiO ③

[0044] C + 0.5O₂ = CO ④

[0045] From ④ to ③, we can obtain NiO + C = Ni + CO.

[0046] According to ΔG 0 The Gibbs free energy of the reduction reaction is calculated using the formula A + BT. The calculation shows that when T = 1000℃, ΔG 0 =-51310<0, therefore the reaction can proceed.

[0047] In summary, both reactions have Gibbs free energies less than 0, allowing both reactions to proceed. Furthermore, according to the oxygen potential diagram, carbon can reduce Cu₂O and NiO oxides in the AuCuNi alloy melt.

[0048] The deoxygenation model of this invention is as follows:

[0049] Carbon and oxygen exhibit mass transfer in the melt. Assuming the reduction of oxides by carbon is described by unsteady diffusion laws:

[0050]

[0051] In the formula, t is time, in seconds; m s D is the initial mass of carbon in the melt, in grams; c =2×10 -5 cm 2 / s (1000℃) is the diffusion coefficient of carbon in the melt; F is the contact area between carbon and the melt, in cm². 2 V is the volume of the gold-copper-nickel alloy melt, in L.

[0052] From this, we can deduce the mass of carbon consumed during the deoxidation process:

[0053]

[0054] Contact area between carbon and melt:

[0055]

[0056] In the formula, L is the length of a single mesh opening of a single carbon fiber mesh, in cm; r is the radius of the carbon fiber deoxidation mesh, in cm.

[0057] Since only Ni and Cu in the gold-copper-nickel alloy are easily oxidized, the volume of the melt participating in the reduction reaction can be calculated based on the mass ratio of Au:Ni:Cu as 80-86:10:4-10.

[0058] V i =iV(i=0.14, 0.16, 0.18, 0.2) (4)

[0059] In the formula, V i The volume of the melt participating in the reduction reaction in the gold-copper-nickel alloy is expressed in cm. 3 .

[0060] (1) Based on the ratio of the relative molecular masses of Cu2O and C after heating and reduction to Cu and CO2, the required mass n2 of Cu2O can be obtained.

[0061] 2Cu₂O + C = 4Cu + CO₂

[0062]

[0063] In the formula, n1 is the mass of C required for the reduction reaction, in g; n2 is the mass of Cu2O required for the reduction reaction, in g. Based on the oxidation reaction between Cu and O2, the mass of O2 is calculated as follows:

[0064] 4Cu + O₂ = 2Cu₂O

[0065]

[0066] In the formula, n3 is the mass of O2 required for the oxidation reaction, in g.

[0067] (2) The mass n5 of the required NiO can be obtained based on the ratio of the relative molecular masses of NiO and C after heating and reduction to Ni and CO.

[0068] NiO + C = Ni + CO

[0069]

[0070] In the formula, n4 is the mass of C required for the reduction reaction, in g; n5 is the mass of NiO required for the reduction reaction, in g. Based on the oxidation reaction between Ni and O2, the mass of O2 is calculated as follows:

[0071] Ni + O₂ = NiO

[0072]

[0073] In the formula, n6 is the mass of O2 required for the oxidation reaction, in g.

[0074] Δm C =n1+n4 (9)

[0075]

[0076] In the formula, Δm C Let g be the total mass of carbon required for the reduction of Cu2O and NiO. The total mass of oxygen required for the oxidation of Cu and Ni, in g.

[0077] The mass of oxygen after deoxygenation can be obtained using the above formula:

[0078]

[0079] In the formula, m i V represents the oxygen content after deoxygenation, in ppm; m0 represents the mass of oxygen before deoxygenation, in g; M is the molar mass (in g / mol); V m It is the molar volume under standard conditions (in L / mol).

[0080] In this embodiment of the invention, the oxygen content of the AuCuNi alloy after deoxidation is calculated by the carbon consumption calculated by the above model, and the deoxidation efficiency of the carbon fiber mesh is obtained by comparing the oxygen content after deoxidation with the initial oxygen content of the AuCuNi alloy.

[0081] Example 1:

[0082] In this embodiment, the mass ratio of pure gold, pure nickel, and pure copper in the AuCuNi alloy is 86:10:4, and the initial oxygen content of the alloy is 29.4 ppm.

[0083] In this embodiment, the AuCuNi alloy melt is deoxidized using the following method:

[0084] (1) Place the AuCuNi alloy into the graphite crucible 4, place the graphite crucible 4 into the 310S stainless steel reduction vessel 6, and place the 310S stainless steel reduction vessel 6 into the resistance furnace 1.

[0085] (2) Open the argon gas valve and adjust the argon gas flow rate to 0.6 L / min·cm. 3 Argon gas enters the 310S stainless steel reduction vessel 6 through the ceramic inlet pipe 9.

[0086] (3) Turn on the resistance furnace 1 and heat the AuCuNi alloy in the graphite crucible 4 to 1000℃ to melt it. Then adjust the extension of the telescopic ceramic drive shaft 10, thereby causing the carbon fiber mesh ceramic support 13 fixedly connected to it to move downward. As a result, the carbon fiber deoxidized mesh 5, which is clamped and fixed by the carbon fiber mesh ceramic support 13, also moves downward and is immersed in the AuCuNi alloy melt. Before adjusting the extension of the telescopic ceramic drive shaft 10, the carbon fiber deoxidized mesh 5 is located as follows: Figure 1At station I, after adjusting the extension of the telescopic ceramic drive shaft 10, the carbon fiber deoxidizing mesh 5 moves downward to station II as shown in Figure 1. Station II is 60mm away from the bottom of the graphite crucible 4. When the carbon fiber deoxidizing mesh 5 enters the AuCuNi alloy melt, it will undergo a reduction reaction with Cu2O and NiO in the AuCuNi alloy melt to deoxidize. During the deoxidation process, the reciprocating motor 12 is turned on. With the reciprocating rotation of the drive shaft of the reciprocating motor 12, the carbon fiber deoxidizing mesh 5 can move downward to the AuCuNi alloy melt. The carbon fiber deoxidizing mesh 5 moves up and down continuously within the CuNi alloy melt, thus disturbing the AuCuNi alloy melt and giving it a certain degree of fluidity. This increases the contact probability between the dissolved Cu2O and NiO in the AuCuNi alloy melt and the carbon fiber deoxidizing mesh 5. In this embodiment, the carbon fiber deoxidizing mesh 5 moves up and down in the AuCuNi alloy melt at a speed of 10 mm / s, and the deoxidation time is 40 min. In this embodiment, the carbon fiber deoxidizing mesh 5 consists of 3 layers, and the pore density of a single carbon fiber mesh is 30 mesh. The CO and CO2 generated during the deoxidation process escape from the melt and are discharged from the resistance furnace 1 through the ceramic exhaust pipe 11. Due to the continuous introduction of argon gas, excess argon gas is also discharged from the ceramic exhaust pipe 11.

[0087] (4) After deoxidation is completed, turn off the reciprocating motor 12, adjust the telescopic ceramic drive shaft 10 to shorten and drive the carbon fiber deoxidizing net 5 to rise to the desired height. Figure 1 At station I, as shown, the resistance furnace 1 is shut down. After the AuCuNi alloy melt solidifies, the argon valve is closed, and after cooling, a deoxidized AuCuNi alloy ingot is obtained.

[0088] The oxygen content in the AuCuNi alloy ingot after deoxidation in this embodiment is calculated to be 11.2 ppm, the deoxidation amount in this embodiment is 18.2 ppm, and the deoxidation rate is 62%.

[0089] Example 2:

[0090] In this embodiment, the mass ratio of pure gold, pure nickel, and pure copper in the AuCuNi alloy is 84:10:6, and the initial oxygen content of the alloy is 33.6 ppm.

[0091] The deoxygenation method in this embodiment is the same as in Example 1, except that the argon flow rate is 0.9 L / min·cm. 3 During the deoxidation process, the carbon fiber deoxidation mesh 5 moves up and down at a speed of 13 mm / s, and the deoxidation time is 60 min. The carbon fiber deoxidation mesh 5 consists of 4 layers, and the mesh density of a single carbon fiber mesh is 33 mesh.

[0092] The oxygen content in the AuCuNi alloy ingot after deoxidation in this embodiment is calculated to be 11.4 ppm, the deoxidation amount in this embodiment is 22.2 ppm, and the deoxidation rate is 66%.

[0093] Example 3:

[0094] In this embodiment, the mass ratio of pure gold, pure nickel, and pure copper in the AuCuNi alloy is 82:10:8, and the initial oxygen content of the alloy is 37.8 ppm.

[0095] The deoxygenation method in this embodiment is the same as in Example 1, except that the argon flow rate is 1.2 L / min·cm. 3 During the deoxidation process, the carbon fiber deoxidation mesh 5 moves up and down at a speed of 16 mm / s, and the deoxidation time is 80 min. The carbon fiber deoxidation mesh 5 consists of 5 layers, and the mesh density of a single carbon fiber mesh is 36 mesh.

[0096] The oxygen content in the AuCuNi alloy ingot after deoxidation in this embodiment is calculated to be 11.8 ppm, the deoxidation amount in this embodiment is 26 ppm, and the deoxidation rate is 68%.

[0097] Example 4:

[0098] In this embodiment, the mass ratio of pure gold, pure nickel, and pure copper in the AuCuNi alloy is 80:10:10, and the initial oxygen content of the alloy is 42ppm.

[0099] The deoxygenation method in this embodiment is the same as in Example 1, except that the argon flow rate is 1.5 L / min·cm. 3 During the deoxidation process, the carbon fiber deoxidation mesh 5 moves up and down at a speed of 20 mm / s, and the deoxidation time is 100 min. The carbon fiber deoxidation mesh 5 consists of 6 layers, and the mesh density of a single carbon fiber mesh is 40 mesh.

[0100] The oxygen content in the AuCuNi alloy ingot after deoxidation in this embodiment is calculated to be 13.1 ppm, the deoxidation amount in this embodiment is 29.5 ppm, and the deoxidation rate is 70%.

[0101] In summary, carbon fiber deoxidation mesh can be used to effectively and rapidly deoxidize AuCuNi alloy melt. The entire deoxidation process is simple to operate, low in cost, and the deoxidation device has a relatively simple structure, which is conducive to industrial application and promotion.

[0102] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for deoxidizing AuCuNi alloy melt using carbon fiber mesh, characterized in that: The deoxygenation method includes the following steps: S1: Place the AuCuNi alloy into a graphite crucible (4), which is placed in a 310S stainless steel reduction vessel (6), which is placed in a resistance furnace (1). S2: Open the argon valve, adjust the argon flow rate, and introduce argon into the 310S stainless steel reduction tank (6) through the ceramic inlet pipe (9) set on the side wall of the 310S stainless steel reduction tank (6); S3: Turn on the resistance furnace (1) to heat the AuCuNi alloy, so that the AuCuNi alloy melts into AuCuNi alloy melt. Adjust the extension of the telescopic ceramic drive shaft (10) to drive the carbon fiber deoxidizing mesh (5) connected to it to move downward and immerse it in the AuCuNi alloy melt, and start the deoxidation treatment of the AuCuNi alloy melt. The CO and CO2 generated in the process are discharged through the ceramic exhaust pipe (11) set on the side wall of the 310S stainless steel reduction tank (6). The carbon fiber deoxidizing mesh (5) is discharged through the ceramic exhaust pipe (11) set on the side wall of the 310S stainless steel reduction tank (6). The carbon fiber mesh ceramic support (13) is clamped and fixed. The carbon fiber mesh ceramic support (13) is fixedly connected to one end of the telescopic ceramic drive shaft (10). The other end of the telescopic ceramic drive shaft (10) passes through the 310S stainless steel reduction tank (6) and the furnace cover (2) of the resistance furnace (1) and is hinged to one end of the second connecting rod. The other end of the second connecting rod is hinged to one end of the first connecting rod. The other end of the first connecting rod is fixedly connected to the drive shaft of the reciprocating motor (12). The telescopic ceramic drive shaft (10) is restricted to moving only along the axial direction by the guide plate. S4: After the reaction in step S3 is completed, adjust the telescopic ceramic drive shaft (10) to shorten. Drive the carbon fiber deoxidation net (5) upward through the telescopic ceramic drive shaft (10) and detach it from the AuCuNi alloy melt. Then, close the resistance furnace (1). After the AuCuNi alloy melt solidifies, close the argon valve and obtain the deoxidized AuCuNi alloy ingot after cooling. During the deoxidation process in step S3, the reciprocating motor (12) is turned on, and the carbon fiber deoxidation mesh (5) is moved up and down in the AuCuNi alloy melt by the reciprocating motor (12). After the deoxidation is completed, the reciprocating motor (12) is turned off. In step S3, the carbon fiber deoxidizing mesh (5) moves up and down in the AuCuNi alloy melt at a speed of 10-20 mm / s, and the deoxidation time is 40-100 min.

2. The method for deoxidizing AuCuNi alloy melt using carbon fiber mesh according to claim 1, characterized in that: The carbon fiber deoxidation mesh (5) is composed of multiple carbon fiber meshes stacked together. The area of ​​a single carbon fiber mesh is 80% of the cross-sectional area of ​​the graphite crucible (4). The thickness of a single carbon fiber mesh is 1 mm, the pore density is 30-40 mesh, and the number of stacked layers of carbon fiber mesh (5) is 3-6.

3. The method for deoxidizing AuCuNi alloy melt using carbon fiber mesh according to claim 1, characterized in that: In the AuCuNi alloy, the mass ratio of pure gold, pure nickel, and pure copper is 80-86:10:4-10.

4. The method for deoxidizing AuCuNi alloy melt using carbon fiber mesh according to claim 1, characterized in that: In step S2, the argon gas flow rate is 0.6 ~ 1.5 L / min·cm. 3 .

5. The method for deoxidizing AuCuNi alloy melt using carbon fiber mesh according to claim 1, characterized in that: In step S3, the AuCuNi alloy is heated to 1000℃ to obtain AuCuNi alloy melt.

6. The method for deoxidizing AuCuNi alloy melt using carbon fiber mesh according to claim 1, characterized in that: In step S3, the carbon fiber deoxidizing mesh (5) is driven downward by the telescopic ceramic drive shaft (10) and stops when the distance between it and the bottom of the graphite crucible (4) is 60mm.

7. The carbon fiber mesh deoxidation method for AuCuNi alloy melt according to claim 1, characterized in that: The ceramic intake pipe (9), ceramic exhaust pipe (11) and 310S stainless steel reduction tank (6) are sealed by welding, and a dynamic seal (7) is provided between the telescopic ceramic drive shaft (10) and the 310S stainless steel reduction tank (6).

8. The method for deoxidizing AuCuNi alloy melt using carbon fiber mesh according to claim 1, characterized in that: The lid of the 310S stainless steel reduction tank (6) is sealed to the tank body by a flange (8).

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