A method for preparing copper-silicon alloy by vortex thermoelectric coupling

Abstract

The present application relates to a kind of copper silicon alloy prepared by vortex thermoelectric coupling method, belong to metallurgical technical field.The pure copper of metal is used as raw material, and copper melt is obtained by induction furnace electric heating rapid melting, vortex is generated in copper melt under the action of mechanical stirring;SiO2 is used as raw material, Mg powder is used as reducing agent, and the mixture is introduced into copper melt by vortex generated by stirring, and magnesium hot reduction reaction occurs in situ to generate Si element, which is dispersedly distributed in Cu melt by mechanical stirring, and additional induction coil is used for heat preservation smelting, so that reduced slag and copper silicon melt are fully separated, wherein excess SiO2 in raw material, excess SiO2 and MgO are slagging, and MgO-SiO2 smelting slag is covered on copper melt to play a protective role.A certain temperature is used to overflow slagging method to discharge MgO-SiO2 smelting slag on the upper layer of melt, and MgO-SiO2-Al2O3 refractory material is prepared after adding Al2O3 and mixing, and the lower layer homogeneous CuSi alloy melt is rapidly cooled by water-cooled crystallizer, there is no waste discharge in the whole process, and copper silicon alloy is realized by clean preparation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgy, and particularly relates to a method for preparing copper-silicon alloy through vortex heat-electric coupling. BACKGROUND

[0002] Copper alloy refers to an alloy formed by adding one or more other elements to pure copper. The alloying characteristics of copper alloy are extremely excellent, and can form various characteristic alloys with most non-metallic and metallic elements. At present, copper alloy has formed nearly ten thousand kinds of product series, two hundred and fifty-five alloy grades, which meet the needs of various industries. After melting, the copper alloy has high hardness and strength, excellent electrical conductivity, and is used to prepare large-scale integrated circuit lead frame and contact materials. The addition of silicon element can form a strengthening phase with other elements, further improving the strength and electrical conductivity of the material.

[0003] Cu-Si-Ni alloy belongs to the age-hardening type alloy, and its biggest feature is that it has very high strength. In recent years, Cu-Si-Ni alloy has been greatly developed as a lead frame material. Kobe Steel in Japan recently developed a KLFA85 alloy based on KLF-1 alloy, which has a strength of more than 800 MPa and an electrical conductivity of 40% IACS. The strength of the alloy is higher than that of Fe-Ni42 alloy, and the electrical conductivity is more than ten times that of Fe-Ni42 alloy. In addition to Japan, many countries in South Korea, Europe and the United States have developed their own Cu-Si-Ni series lead frame alloys. China is late in the development of this type of alloy. According to market demand, it is urgent to develop China's own Cu-Si-Ni series lead frame materials to replace imported materials. According to the literature, it is found that the development of new alloy materials and appropriate component design are the basis for realizing high performance. Through consulting relevant literature, it is found that copper-silicon alloy is a good elastic alloy, but the strength and electrical conductivity of copper-silicon binary alloy are low. In order to develop a copper-silicon alloy with performance reaching or exceeding that of tin-phosphor bronze QSn6.5-0.1, the copper-silicon binary alloy needs to be optimized.

[0004] Currently, the preparation process of CuSi alloy has non-vacuum melting method and vacuum melting method. The patent with application number 202110896167.0 takes electrolytic Cu plate and Si powder as raw materials, and puts the prepared raw materials into the crucible in the order of putting Si powder first and then putting electrolytic copper plate according to the mass ratio of 5:1; then the mechanical pump is started, and when the vacuum pressure in the furnace is less than 0.08 MPa, the Roots pump is started and the composite vacuum gauge is opened; when the pressure in the furnace reaches the heating condition, heating and melting are started; then casting is carried out under vacuum; CuSi20 is prepared by combining vacuum melting and vacuum casting; but the above patent takes high-purity electrolytic copper plate and Si powder as raw materials, which increases the cost of raw materials, and the vacuum degree is high and the process is complicated, so how to reduce the production cost of the existing production technology and prepare copper-silicon alloy with performance comparable to or even better than commercial alloy to obtain good economic benefit is the research direction of CuSi alloy. SUMMARY

[0005] To solve the above problems, the present application provides a method for preparing copper-silicon alloy by vortex thermoelectric coupling, which specifically comprises preparing Cu block, SiO2 powder and Mg powder, and then adding the prepared Cu block, SiO2 powder and Mg powder into the copper melt according to the mass of the desired copper-silicon alloy. The molar ratio of the generated magnesium oxide to the excess added silicon oxide is 1:1 for slag making. The mixture of SiO2 powder and Mg powder is added into the melt by mechanical stirring to generate vortex in the copper melt. The high-temperature melt is subjected to electromagnetic induction slag conditioning under the protection of the molten slag to ensure effective separation of the slag and the gold. The melting temperature is 1600-1750℃, and the time is 15 minutes. Finally, the copper-silicon alloy and the melting slag of MgO·SiO2 are obtained by cooling and solidification. The MgO·SiO2 slag is directly discharged by overflow slagging method to prepare MgO-Al2O3-SiO2 refractory material.

[0006] A method for preparing copper-silicon alloy by vortex thermoelectric coupling, comprising the following steps:

[0007] (1) Taking metal copper as raw material, melting to obtain copper melt by induction heating to 1250-1300℃, and forming vortex in the copper melt by vortex mechanical stirring;

[0008] (2) After drying SiO2 powder at 150℃ for 24h, mix it with Mg powder, and then obtain the mixture by ball milling and briquetting. The mixture is added into the copper melt by vortex method. The mixture reacts under the high-temperature environment of the melt and the vortex stirring to obtain alloy melt, realizing in-situ addition of Si in the Cu melt, and the melting slag is covered on the CuSi melt;

[0009] (3) The alloy melt is heated and melted under the action of electromagnetic field, and Si element is obtained by metal thermal reduction, and homogeneous copper-silicon alloy melt and reduced melting slag are obtained under the action of stirring;

[0010] (4) the MgO-SiO2 smelting slag on the upper layer of the alloy melt is directly discharged by overflow slagging method to prepare MgO-Al2O3-SiO2 refractory material; and the CuSi alloy melt on the lower layer of the alloy melt is cast and cooled to obtain CuSi alloy ingot after solidification.

[0011] Further, the vortex in step (2) uses straight-blade open turbine paddle stirring, and the stirring speed is 100-150 rpm.

[0012] Further, the addition amount of SiO2 in step (2) is proportioned according to the chemical reaction equation (1), so that the Si content in the alloy is 18%-22%, i.e. x is between 0.5-0.65 mol; meanwhile, the MgO generated in the reaction and the excess SiO2 form MgO-SiO2 slag, so that the melting point of the slag is between 1500-1600℃;

[0013] Cu+3xSiO2+2xMg=[Cu-xSi]+2x(MgO-SiO2) (1)

[0014] Further, the ball milling in step (2) is mixed on a high-energy ball mill for 30-50 min, and the pressure of the compacted body is 15-20 Mpa.

[0015] Further, the heating smelting temperature in step (3) is 1600-1750℃, the time is 5-15 min, and the electromagnetic frequency of the electromagnetic field is 2000-5000 Hz.

[0016] Further, the MgO-Al2O3-SiO2 refractory material in step (4) is prepared by adding different proportions of Al2O3 in the MgO-SiO2 smelting slag to obtain different grades of forsterite refractory materials.

[0017] Further, the cooling of the CuSi alloy melt in step (4) is carried out in a water-cooled crystallizer at a solidification speed of 5-10℃ / s.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] (1) low production cost, compared with vacuum smelting, the process uses cheap SiO2 as raw material, and the requirement for vacuum degree is low in the in-situ reduction by magnesium heat in a non-vacuum environment;

[0020] (2) superior homogeneity, compared with traditional metallurgical methods, the process uses the synergistic effect of electromagnetic stirring and mechanical stirring to make the Si element uniformly and dispersedly distributed in the Cu matrix, and the cooling rate of the CuSi melt in the water-cooled crystallizer ensures the solution of the segregation problem caused in the solidification process.

[0021] (3) High resource utilization rate. The obtained reducing slag can be directly used to prepare MgO-Al2O3-SiO2 refractory materials. The Cu melt is isolated from air under the action of protective slag, and the burn-off rate is reduced. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for preparing copper-silicon alloys using eddy current thermoelectric coupling according to the present invention. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] A method for preparing copper-silicon alloys via eddy current thermoelectric coupling, such as... Figure 1 As shown, it includes the following steps:

[0026] (1) Prepare Cu blocks, SiO2 powder and Mg powder according to the composition of the CuSi25 alloy ingot to be prepared. Put 5 kg of Cu blocks into an induction furnace and heat it to 1300℃ so that the Cu blocks are completely melted and in a molten state. Add the mechanical stirring system.

[0027] (2) Place the SiO2 required for the reaction in an oven at 150°C for 24 hours. When mixing the materials, put 3572g of SiO2 powder and 953g of Mg powder into a mixing tank and mix them in a ball mill for 40 minutes. Press the mixture at 20 MPa, set the stirring speed to 150 rpm, and disperse it in the melt under the combined action of mechanical stirring and electromagnetic stirring. The mixture undergoes a reduction reaction under the high temperature environment of the melt and the action of eddy current stirring, realizing the in-situ addition of Si in the Cu melt. The smelting slag covers the copper melt, isolating it from the air and playing a protective role. Finally, a high temperature melt composed of alloy melt and MgO·SiO2 reduction slag is obtained.

[0028] (3) The high-temperature melt is smelted into alloy slag under the action of an electromagnetic field. The electromagnetic induction parameters are: 5000Hz, smelting temperature 1700℃, and smelting time 15min. The upper layer forms MgO·SiO2 slag, and the lower layer forms CuSi alloy melt. The elemental Si obtained by metallothermic reduction is used to obtain a homogeneous copper-silicon alloy melt and a melt of reduced smelting slag under stirring. This ensures that the slag also presents a molten state and improves the separation effect of slag and gold.

[0029] (4) The upper MgO-SiO2 slag is discharged by overflow slagging method to prepare MgO-Al2O3-SiO2 refractory material; the lower part of the CuSi alloy melt is cast into a water-cooled crystallizer to rapidly solidify into a copper-silicon alloy ingot, the Si content in the copper-silicon alloy is 23-25%, and the cooling rate is 15 ℃ / s.

[0030] Example 2

[0031] A method for preparing a copper-silicon alloy by vortex-thermal-electric coupling, as shown in Figure 1 , includes the following steps:

[0032] (1) According to the composition of the CuSi23 alloy ingot to be prepared, Cu blocks, SiO2 powder and Mg powder are prepared, 5 kg of Cu blocks are put into an induction furnace, heated to 1300 ℃ to completely melt the Cu blocks into a melt state, and a mechanical stirring system is added;

[0033] (2) The SiO2 required for the reaction is placed in an oven at 150 ℃ for 24 h. When mixing the ingredients, 3201 g of SiO2 powder and 854 g of Mg powder are put into a mixing tank, mixed on a ball mill for 40 min, and the mixed material is pressed at 18 Mpa, the stirring speed is set to 130 rpm, and the mixed material is dispersed in the melt under the synergistic action of mechanical stirring and electromagnetic stirring, the mixed material undergoes a reduction reaction under the action of vortex stirring in a high-temperature melt environment, realizing in-situ addition of Si in the Cu melt, the smelting slag is covered on the copper melt to isolate air and play a protective role, and finally a high-temperature melt composed of alloy melt and MgO-SiO2 reduction slag is obtained;

[0034] (3) The high-temperature melt is subjected to alloy slag smelting under the action of an electromagnetic field, the electromagnetic induction parameters are: 4500 Hz, the smelting temperature is 1650 ℃, and the smelting time is 13 min, the upper layer forms MgO-SiO2 slag, and the lower layer forms CuSi alloy melt; Si element obtained by metal thermal reduction and homogeneous copper-silicon alloy melt and reduction smelting slag melt are obtained under the action of stirring; ensure that the slag also presents a melt state to improve the separation effect of slag and gold;

[0035] (4) The upper MgO-SiO2 slag is discharged by overflow slagging method to prepare MgO-Al2O3-SiO2 refractory material; the lower part of the CuSi alloy melt is cast into a water-cooled crystallizer to rapidly solidify into a copper-silicon alloy ingot, the Si content in the copper-silicon alloy is 23-25%, and the cooling rate is 15 ℃ / s.

[0036] Example 3

[0037] A method for preparing a copper-silicon alloy by vortex-thermal-electric coupling, as shown in Figure 1 , includes the following steps:

[0038] (1) According to the composition of the CuSi20 alloy ingot to be prepared, Cu blocks, SiO2 powder and Mg powder are prepared, 5 kg of Cu blocks are put into an induction furnace, heated to 1300°C to completely melt the Cu blocks into a molten state, and a mechanical stirring system is added;

[0039] (2) SiO2 required for the reaction is placed in an oven at 150°C for 24h. When mixing the ingredients, 2679g of SiO2 powder and 714g of Mg powder are put into a mixing tank, mixed on a ball mill for 40min, and the mixed material is pressed into a compact at 16Mpa, and the stirring speed is set to 130rpm. The compact is added to the melt in batches by the vortex generated by mechanical stirring to obtain an alloy melt. The mixed material undergoes a reduction reaction under the action of high-temperature molten environment and vortex stirring, realizes in-situ addition of Si in the Cu melt, and the smelting slag covers the copper melt to isolate air and play a protective role;

[0040] (3) The high-temperature melt is subjected to alloy slag smelting under the action of an electromagnetic field. The electromagnetic induction parameters are: 3500Hz, smelting temperature 1630°C, and smelting time 12min. The upper layer forms MgO·SiO2 slag, and the lower layer forms CuSi alloy melt. The Si element obtained by metal thermal reduction is dispersed in the melt under the synergistic action of mechanical stirring and electromagnetic stirring, and finally a high-temperature melt composed of alloy melt and MgO·SiO2 reduction slag is obtained. The slag also presents a molten state to improve the separation effect of slag and metal;

[0041] (4) The upper layer MgO·SiO2 slag is discharged by overflow slagging method to prepare MgO-Al2O3-SiO2 refractory material; the lower part CuSi alloy melt is cast into a water-cooled crystallizer for rapid solidification into a copper-silicon alloy ingot. The Si content in the copper-silicon alloy is 18-21%, and the cooling rate is 12°C / s.

[0042] Example 4

[0043] A method for preparing a copper-silicon alloy by vortex thermoelectric coupling, as shown in Figure 1 , comprising the following steps:

[0044] (1) According to the composition of the CuSi18 alloy ingot to be prepared, Cu blocks, SiO2 powder and Mg powder are prepared, 5 kg of Cu blocks are put into an induction furnace, heated to 1300°C to completely melt the Cu blocks into a molten state, and a mechanical stirring system is added;

[0045] (2) Put the required SiO2 for the reaction in the oven at 150°C for 24 hours. When mixing the ingredients, put 2353g of SiO2 powder and 627g of Mg powder into the mixing tank, mix for 40 minutes on the ball mill, press the mixture to 15Mpa, set the stirring speed to 120rpm, and disperse it in the melt under the combined action of mechanical stirring and electromagnetic stirring. The mixture undergoes a reduction reaction in the high-temperature environment of the melt and under the action of vortex stirring, realizing in-situ addition of Si in the Cu melt. The smelting slag covers the copper melt, isolating air and providing protection. Finally, a high-temperature melt composed of alloy melt and MgO·SiO2 reduction slag is obtained;

[0046] (3) The high-temperature melt is subjected to alloy slag smelting under the action of an electromagnetic field. The electromagnetic induction parameters are: 3000Hz, smelting temperature 1600°C, and smelting time 10 minutes. The upper layer forms MgO·SiO2 slag, and the lower layer forms CuSi alloy melt. Si is obtained by metal thermal reduction, and a homogeneous copper-silicon alloy melt and reduction slag melt are obtained under the action of stirring. The slag also presents a molten state, improving the separation effect of slag and metal;

[0047] (4) The upper layer of MgO·SiO2 slag is removed by overflow slagging method to prepare MgO-Al2O3-SiO2 refractory material. The lower part of the CuSi alloy melt is cast into a water-cooled crystallizer for rapid solidification into a copper-silicon alloy ingot. The Si content in the copper-silicon alloy is 17-19%, and the cooling rate is 11°C / s.

[0048] Example 5

[0049] A method for preparing a copper-silicon alloy by vortex heat and thermoelectric coupling, as shown in Figure 1 , comprising the following steps:

[0050] (1) Prepare Cu blocks, SiO2 powder and Mg powder according to the composition of the CuSi15 alloy ingot to be prepared. Put 5kg of Cu blocks into an induction furnace, heat to 1300°C to completely melt the Cu blocks into a molten state, and add a mechanical stirring system.

[0051] (2) The SiO2 required for the reaction is placed in an oven at 150°C for 24 hours. The mixed ratio of SiO2 powder and Mg powder is 3.75:1 by weight when mixing the ingredients, and is put into a mixing tank, mixed on a ball mill for 40 minutes, and the mixture is pressed into a compact at 15Mpa, with the stirring speed set at 120rpm, and dispersed in the melt by the combined action of mechanical stirring and electromagnetic stirring. The final high-temperature melt is composed of alloy melt and MgO·SiO2 reduction slag. The mixture is subjected to a reduction reaction in the high-temperature melt environment and under the action of eddy current stirring, realizing in-situ addition of Si in the Cu melt. The smelting slag is covered on the copper melt to protect it from air;

[0052] (3) The high-temperature melt is subjected to alloy slag smelting under the action of an electromagnetic field. The electromagnetic induction parameters are: 2000Hz, smelting temperature 1600°C, and smelting time 5min. The upper layer forms MgO·SiO2 slag, and the lower layer forms CuSi alloy melt. The Si element obtained by metal thermal reduction is homogeneous under the action of stirring, and the copper-silicon alloy melt and the reduction smelting slag melt are obtained. The slag is also in a molten state to improve the separation effect of slag and metal;

[0053] (4) The upper layer of MgO·SiO2 slag is discharged by overflow slagging method to prepare MgO-Al2O3-SiO2 refractory material. The lower part of the CuSi alloy melt is cast into a water-cooled crystallizer for rapid solidification into a copper-silicon alloy ingot. The Si content in the copper-silicon alloy is 14-16%, and the cooling rate is 10°C / s.

Claims

1. A method for preparing copper-silicon alloys via eddy current thermoelectric coupling, characterized in that, Includes the following steps: (1) Using metallic copper as raw material, copper melt is obtained by induction heating to 1250-1300℃, and eddy current is formed in the copper melt by eddy current mechanical stirring; (2) After drying SiO2 powder at 150℃ for 24h, it is mixed with Mg powder. The resulting mixture is ball-milled and then pressed into a blank. It is then added to the copper melt by eddy current. The mixture undergoes a reduction reaction under the high temperature environment of the melt and the eddy current stirring action to obtain an alloy melt, thereby realizing the in-situ addition of Si to the Cu melt. The smelting slag covers the CuSi melt. (3) The alloy melt is heated and smelted under the action of an electromagnetic field, and Si element is obtained through metal thermal reduction. A homogeneous copper-silicon alloy melt and reduction smelting slag are obtained under the action of stirring. (4) The MgO·SiO2 smelting slag on the upper layer of the alloy melt is directly discharged by overflow slag discharge method to prepare MgO-Al2O3-SiO2 refractory material; the CuSi alloy melt in the lower layer of the alloy melt is cast, cooled and solidified to obtain CuSi alloy ingot. Step (2) The amount of SiO2 added is according to the chemical reaction equation (1) to ensure that the Si content in the alloy is between 18% and 22%, that is, x is between 0.5 and 0.65 mol; at the same time, the MgO produced by the reaction forms MgO·SiO2 slag with the excess SiO2, so that the melting point of the slag is between 1500℃ and 1600℃. Cu+3xSiO2+2xMg=[Cu-xSi]+2x(MgO·SiO2) (1).

2. The method for preparing copper-silicon alloys by eddy current thermoelectric coupling according to claim 1, characterized in that, The vortex described in step (2) is stirred using a straight-blade open turbine propeller with a stirring speed of 100~150 rpm.

3. The method for preparing copper-silicon alloys by eddy current thermoelectric coupling according to claim 1, characterized in that, The ball milling in step (2) is performed by mixing on a high-energy ball mill for 30-50 minutes, and the pressing pressure is 15-20 MPa.

4. The method for preparing copper-silicon alloys by eddy current thermoelectric coupling according to claim 1, characterized in that, The heating and melting temperature in step (3) is 1600~1750℃, the time is 5-15 min, and the electromagnetic frequency of the electromagnetic field is 2000Hz-5000Hz.

5. The method for preparing copper-silicon alloys by eddy current thermoelectric coupling according to claim 1, characterized in that, The MgO-Al2O3-SiO2 refractory material mentioned in step (4) is a magnesium olivine refractory material of different grades made by adding different proportions of Al2O3 to MgO·SiO2 smelting slag.

6. The method for preparing copper-silicon alloys by eddy current thermoelectric coupling according to claim 1, characterized in that, The CuSi alloy melt cooling in step (4) is carried out in a water-cooled crystallizer at a solidification rate of 5~10℃ / s.

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