Method for designing and preparing silicon-based high-entropy alloy using photovoltaic silicon waste by means of compensation method

Abstract

The present application discloses a method for designing and preparing a silicon-based high-entropy alloy using photovoltaic silicon waste by means of a compensation method. The method specifically comprises the following steps: (1) pre-treating a silicon wafer cutting slurry; (2) performing high-temperature refining and furnace cooling; (3) crushing the resulting material, melting same with a solvent metal, and performing directional solidification after the metal is completely melted, followed by furnace cooling; (4) cutting and separating the resulting material along an interface between a silicon-rich region and a silicon-based alloy to obtain the silicon-rich region; (5) preparing a target metal material on the basis of a composition ratio of a silicon-based high-entropy alloy; and (6) smelting the silicon-rich region and the target metal material, leaving the smelting product to stand while maintaining the temperature, and pouring the smelting product into a mold, followed by furnace cooling, thereby obtaining the final product. The new idea of using the "compensation method" to design and prepare the silicon-based high-entropy alloy in the present application can shorten an impurity removal process and achieves the preparation of a high-quality high-entropy alloy material by means of rational composition formulation and microstructure control.

Description

A method for designing and preparing silicon-based high-entropy alloy by compensation method using photovoltaic silicon waste

[0001] Cross-reference to Related Applications

[0002] This application claims priority to the Chinese patent application No. 2024111216747, filed on August 15, 2024, and entitled "A method for designing and preparing silicon-based high-entropy alloy by compensation method using photovoltaic silicon waste", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of secondary resource high-value recycling technology, more specifically to a method for designing and preparing silicon-based high-entropy alloy by compensation method using photovoltaic silicon waste. BACKGROUND

[0004] Under the background of promoting the realization of the dual goals of "carbon peak" and "carbon neutrality", the green renewable new energy photovoltaic industry represented by solar energy is showing a rapid development momentum in China.

[0005] Silicon wafer is an important component of solar cells. Currently, its production cutting method is diamond wire cutting technology. This technology has the advantages of high production efficiency, high control precision, low environmental load in production process, easy recovery of cutting waste, and shallow mechanical damage to the surface of silicon wafer. Since 2018, it has gradually become the mainstream technology and completely replaced the original mortar cutting technology in 2019. In the cutting process, the diameter of the diamond wire is 60-80 μm, and the thickness of the silicon wafer is generally 170-180 μm. The diamond wire needs to be embedded in the silicon ingot to be cut, and both of them move relatively. Due to the gap generated by cutting, about 35%-40% of high-purity silicon is lost. The SiO2 oxide formed on the high-speed cutting surface, carbon particles falling off the diamond wire, metal impurities, and organic solvents are mixed together to form diamond wire cutting silicon powder waste.

[0006] Under the background of continuous increase in new installed capacity of photovoltaic installation, the production of silicon wafers is huge, and a large amount of silicon waste will be generated in the production process. According to statistics, about 1000 tons of silicon waste are generated while producing 1 GW of silicon wafers. If it is not recycled and reused, it will cause a lot of resource waste, economic loss, and environmental pollution. The state strongly supports the research and development of solid waste resource utilization technology, so it should vigorously develop secondary utilization of silicon resources, develop green, high-value, and efficient silicon resource processing technology, and realize the gradient disposal and value-added utilization of silicon wafer cutting waste. This not only can reduce silicon resource consumption and carbon emissions, reduce environmental pollution, but also can create huge economic benefits, reduce the production cost of the photovoltaic industry, promote the sustainable development of the photovoltaic industry, and has great practical significance for achieving the "double carbon" goal.

[0007] As the large-scale production of diamond wire cutting technology in our country has been realized in recent years, the recycling of silicon waste is still in the primary stage. There are the following difficulties in the research carried out by domestic and foreign researchers: (1) purification and recycling. The current research still has the shortcomings of failing to realize the synchronous control or removal of the oxidation layer and impurities. (2) Preparation of catalytic materials. The applicable surface properties can be obtained only after complex processing steps. (3) Preparation of lithium ion battery materials. The synthesis cost of nano-silicon anode is high and the actual energy density is low.

[0008] Therefore, how to recycle and reuse the silicon waste is a problem that those skilled in the art need to solve. SUMMARY

[0009] Therefore, the purpose of the present application is to provide a method for designing and preparing silicon-based high-entropy alloys from photovoltaic silicon waste by compensation method. By using the "compensation method", the silicon-based high-entropy alloy with uniform metallographic structure and no segregation is designed and synthesized from photovoltaic silicon waste at one time, so as to solve the problems of difficult removal of the surface oxidation layer of cutting silicon waste and complex impurity elements in the prior art.

[0010] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0011] A method for designing and preparing silicon-based high-entropy alloys from photovoltaic silicon waste by compensation method, specifically comprising the following steps:

[0012] (1) pretreating the silicon wafer cutting slurry to obtain silicon wafer cutting waste;

[0013] (2) high-temperature refining the silicon wafer cutting waste, and cooling in the furnace to obtain refined silicon ingot;

[0014] (3) crushing the refined silicon ingot, and melting with a solvent metal, then directional solidification after the metal is completely melted, and cooling in the furnace to obtain a silicon-based high-entropy alloy precursor;

[0015] (4) cutting and separating the silicon-based high-entropy alloy precursor along the interface between the silicon-rich region and the silicon-based alloy to obtain the silicon-rich region for standby use;

[0016] (5) preparing target metal materials according to the component proportion of the silicon-based high-entropy alloy;

[0017] (6) melting the silicon-rich region and the target metal materials, standing and heat preservation, and pouring into a mold, and cooling in the furnace to obtain the silicon-based high-entropy alloy.

[0018] Further, in the above step (1), the silicon wafer cutting slurry is the silicon-containing cutting waste liquid produced in the production cutting process of single crystal silicon rods and / or polycrystalline silicon rods without any treatment.

[0019] Further, in the step (1), the pretreatment includes solid-liquid separation, dehydration and drying, and the conditions are oxygen isolation or inert gas. Further, the drying is vacuum drying, and the temperature is 60-100℃, preferably 80℃, 85℃ or 90℃; and the pressure is not higher than -0.6 Bar.

[0020] The above further beneficial effect is that, by the pretreatment, the surface oxide layer of the silicon wafer cutting waste can be reduced and oxidation can be prevented.

[0021] Further, in the step (2), the high-temperature refining device is an induction furnace or an electric arc furnace; the high-temperature refining temperature is not lower than 1600℃, preferably 1650℃, 1800℃ or 1850℃; the high-temperature refining pressure is not higher than 50 Pa or inert gas is introduced under normal pressure; and the high-temperature refining time is 0.5-3h, preferably 0.5h or 1h.

[0022] The above further beneficial effect is that, by the high-temperature refining, volatile impurities (including O, P, Al, Ca, etc.) in the silicon wafer cutting waste can be removed.

[0023] Further, in the step (3), the solvent metal is at least one of aluminum (Al), tin (Sn) and copper (Cu).

[0024] The above further beneficial effect is that the solvent metal selected in the application has a certain adsorption effect on the metal impurities in the refined silicon ingot.

[0025] Further, in the step (3), the melting device is a directional solidification resistance furnace or a directional solidification induction furnace; the melting temperature is not lower than 1450℃, preferably 1450℃ or 1500℃; the melting pressure is not higher than 50 Pa or inert gas is introduced under normal pressure; and the directional solidification time is 0.5-80h, preferably 6.5h, 10h or 18h.

[0026] The above further beneficial effect is that, by the melting and directional solidification, part of the Fe, Ti, Ni and other metal impurities can be removed without being completely removed, and a certain amount of solvent metal can be introduced in a controllable manner, and the residual metal impurities and the introduced solvent metal are the target metal materials required for the subsequent preparation of silicon-based high-entropy alloy, thereby shortening the impurity removal process.

[0027] Further, in the step (5), the target metal material is at least four of chromium (Cr), aluminum (Al), iron (Fe), copper (Cu), tin (Sn), germanium (Ge), antimony (Sb), manganese (Mn), cobalt (Co), nickel (Ni), gallium (Ga) and niobium (Nb), preferably chromium, aluminum, iron and copper, or aluminum, tin, germanium, gallium and niobium, or iron, copper, tin, germanium and antimony.

[0028] Further, in the step (6), the melting device is an induction furnace or an arc furnace; the melting temperature is not less than 1450℃, preferably 1550℃, 1800℃ or 2500℃; and the melting pressure is not higher than 50 Pa or under normal pressure with inert gas.

[0029] Further, in the step (6), the standing time is 0.5-2.5 h, preferably 0.5 h.

[0030] Further, in the step (6), the silicon-based high-entropy alloy is Al-Cr-Cu-Fe-Si high-entropy alloy, Nb-Al-Ga-Ge-Si-Sn high-entropy alloy or Ge-Si-Sn-Cu-Fe-Sb high-entropy alloy, the atomic mass percentage of each element is 5%-35%, and the total atomic mass percentage of all elements is 100%. Further, the silicon-based high-entropy alloy is Al2CrCuFeSi high-entropy alloy, Nb3(Al 0.1 Ga 0.1 Ge 0.2 Si 0.3 Sn 0.3 ) high-entropy alloy or Ge2Si2-SnCu 0.5 Fe 0.5 Sb 0.5 high-entropy alloy.

[0031] According to the above technical solution, compared with the prior art, the application has the following advantages:

[0032] 1. The application starts from the perspective of cross-disciplines, and according to the unique physical and chemical properties of diamond wire-cut silicon waste in the photovoltaic industry and the natural "endowment" possessed by the silicon waste as a raw material for preparing silicon-based high-entropy alloy, the method and route of "vacuum refining combined with solvent refining assisted silicon waste purification-alloying design for preparing high-entropy alloy recycling" are carried out by adopting the "compensation concept" first proposed in combination with vacuum refining and electromagnetic melting, which has the advantages of short process, low cost, large-scale value-added utilization, environmental protection, no pollution and sustainable development.

[0033] 2. The application uses vacuum / inert gas atmosphere conditions to avoid secondary oxidation of the raw material, improve the impurity removal effect, and has the advantages of high efficiency and energy saving.

[0034] 3. Since the silicon waste itself contains metal impurities such as iron, nickel, aluminum and copper, the application can omit part of the metal impurity removal process, shorten the purification process, and directly prepare high-entropy alloy by adding target elements to the obtained silicon-based alloy.

[0035] 4、The application utilizes electromagnetic metallurgy technology, controllably introduces a certain amount of solvent metals such as aluminum, tin and copper, further removes non-target impurity elements in the silicon waste material while reducing the smelting temperature, and adds the solvent metals as raw materials for subsequent preparation of silicon-based high-entropy alloy, so as to realize the purpose of preparing silicon-based high-entropy alloy material precursors.

[0036] 5、The new idea of using the "compensation method" to design and prepare silicon-based high-entropy alloy can shorten the impurity removal process, and through reasonable composition adjustment and organization control, high-quality high-entropy alloy materials can be prepared.

[0037] 6、The application is very suitable for preparing multi-component alloy materials (i.e. high-entropy alloy materials) in view of the low silicon recovery rate and the presence of many impurity elements in the diamond wire cutting silicon waste material, aiming to fully utilize the existing resource endowment of silicon waste material and combine it with high-entropy alloy, so as to convert waste into treasure. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all the embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the application.

[0039] Embodiment 1

[0040] The method for preparing silicon-based high-entropy alloy by using photovoltaic silicon waste through the compensation method specifically includes the following steps:

[0041] (1) The untreated silicon-containing powder cutting waste liquid generated in the production cutting process of the single crystal silicon rod is subjected to solid-liquid separation, dehydration, and drying dehydration to constant weight by using a vacuum drying box with a temperature of 85°C and a pressure not higher than-0.6 Bar under oxygen isolation conditions, to obtain silicon wafer cutting waste;

[0042] (2) The silicon wafer cutting waste is placed in a graphite crucible, and then the graphite crucible is placed in a vacuum induction furnace for high-temperature refining, with a furnace pressure not higher than 50 Pa, heating for 0.5 h, and then maintaining at 1650°C for 1 h, and cooling with the furnace, to obtain a refined silicon ingot;

[0043] (3) The refined silicon ingot is crushed and placed with the solvent metal aluminum in a vacuum directional solidification electric resistance furnace for melting, with a temperature of 1450°C and a furnace pressure not higher than 50 Pa, and after the metal is completely melted, the temperature is lowered to the liquidus temperature 1060°C of the Si-Al system, and directional solidification is performed at a rate of 1 μm / s for 18 h, and the furnace is cooled, to obtain a silicon-based high-entropy alloy precursor;

[0044] (4) cutting and separating the silicon-based high-entropy alloy precursor along the interface between the silicon-rich region and the Si-Al alloy to obtain the silicon-rich region for standby;

[0045] (5) preparing target metal materials of chromium, aluminum, iron and copper according to the component proportion of the Al2CrCuFeSi high-entropy alloy;

[0046] (6) placing the silicon-rich region and the target metal materials of chromium, aluminum, iron and copper in a vacuum induction furnace for smelting, with a temperature of 1800℃, a furnace pressure of not higher than 50 Pa, standing for 0.5 h, pouring into a mold and cooling with the furnace to obtain the Al2CrCuFeSi high-entropy alloy.

[0047] Example 2

[0048] The method for preparing a silicon-based high-entropy alloy by using photovoltaic silicon waste through a compensation method specifically includes the following steps:

[0049] (1) performing solid-liquid separation, dehydration and drying dehydration to constant weight on the untreated silicon-containing cutting waste liquid generated in the production cutting process of a single crystal silicon rod under oxygen isolation conditions, using a vacuum drying box with a temperature of 80℃ and a pressure of not higher than -0.6 Bar to obtain silicon wafer cutting waste;

[0050] (2) placing the silicon wafer cutting waste in a graphite crucible, and then placing the graphite crucible in a vacuum induction furnace for high-temperature refining, with a furnace pressure of not higher than 50 Pa, heating for 0.5 h, and then standing for 1 h at 1800℃, and cooling with the furnace to obtain a refined silicon ingot;

[0051] (3) crushing the refined silicon ingot, and placing it and a solvent metal tin in a vacuum directional solidification induction furnace for smelting, with a temperature of 1500℃ and a furnace pressure of not higher than 50 Pa, and then cooling to the liquidus temperature 1332℃ of the Si-Sn system after the metal is completely melted, and directionally solidifying downward at a rate of 2 μm / s for 10 h, and cooling with the furnace to obtain a silicon-based high-entropy alloy precursor;

[0052] (4) cutting and separating the silicon-based high-entropy alloy precursor along the interface between the silicon-rich region and the Si-Sn alloy to obtain the silicon-rich region for standby;

[0053] (5) preparing target metal materials of aluminum, tin, germanium, gallium and niobium according to the component proportion of the Nb3(Al 0.1 Ga 0.1 Ge 0.2 Si 0.3 Sn 0.3 ) high-entropy alloy;

[0054] (6) The silicon-rich region and the target metal material aluminum, tin, germanium, gallium, and niobium are placed in a vacuum induction furnace for smelting, the temperature is 2500°C, the pressure in the furnace is not higher than 50 Pa, and the temperature is kept for 0.5 h, then poured into a mold and cooled in the furnace to obtain Nb3(Al 0.1 Ga 0.1 Ge 0.2 Si 0.3 Sn 0.3 ) high-entropy alloy.

[0055] Example 3

[0056] The method for preparing a silicon-based high-entropy alloy by using photovoltaic silicon waste through a compensation method specifically includes the following steps:

[0057] (1) The silicon-containing powder cutting waste liquid generated in the production cutting process without any treatment is subjected to solid-liquid separation, dehydration, and drying dehydration to constant weight by using a vacuum drying box with a temperature of 90°C and a pressure not higher than -0.6 Bar under oxygen isolation conditions to obtain silicon wafer cutting waste;

[0058] (2) The silicon wafer cutting waste is placed in a graphite crucible, and then the graphite crucible is placed in a vacuum induction furnace for high-temperature refining, the pressure in the furnace is not higher than 50 Pa, and the temperature is kept for 0.5 h at 1850°C, and then cooled in the furnace to obtain a refined silicon ingot;

[0059] (3) The refined silicon ingot is crushed, and then melted with a solvent metal copper in a directional solidification induction furnace, the temperature is 1450°C, and inert gas argon is introduced into the furnace, and then the temperature is lowered to the liquidus temperature 1075°C of the Si-Cu system, and then directional solidification is performed at a rate of 3 μm / s for 6.5 h, and then cooled in the furnace to obtain a silicon-based high-entropy alloy precursor;

[0060] (4) The silicon-based high-entropy alloy precursor is cut and separated along the interface between the silicon-rich region and the Si-Cu alloy to obtain the silicon-rich region for standby use;

[0061] (5) The target metal materials iron, copper, tin, germanium, and antimony are prepared according to the component ratio of Ge2Si2SnCu 0.5 Fe 0.5 Sb 0.5 high-entropy alloy;

[0062] (6) The silicon-rich region and the target metal material iron, copper, tin, germanium, and antimony are placed in a vacuum arc furnace for smelting, the temperature is 1550°C, the pressure in the furnace is not higher than 10 Pa, and the temperature is kept for 0.5 h, then poured into a mold and cooled in the furnace to obtain Ge2Si2SnCu 0.5 Fe 0.5 Sb 0.5 high-entropy alloy.

[0063] Performance test

[0064] 1. Take the Al2CrCuFeSi high-entropy alloy prepared in Example 1, and measure the hardness under a load of 1 kg to reach 782 HV, which has great application potential in the fields of aerospace, aviation, automobiles, ships, weapons, etc. which have higher requirements for material density and hardness.

[0065] 2. Take the Nb3(Al 0.1 Ga 0.1 Ge 0.2 Si 0.3 Sn 0.3 ) high-entropy alloy prepared in Example 2, and measure that the magnetization and resistivity change with temperature to have a superconducting transition at 13 K.

[0066] 3. Take the Ge2Si2SnCu 0.5 Fe 0.5 Sb 0.5 high-entropy alloy prepared in Example 3, crush, ball mill under an argon atmosphere at a speed of 350 rpm for 3.5 h, then assemble a lithium ion battery with the high-entropy alloy as the negative electrode and a lithium sheet as the positive electrode, and test the electrochemical performance, and measure that the first discharge capacity is as high as 1528 mAh / g, the first charge capacity is 1425 mAh / g, and the first coulombic efficiency is as high as 93%, which has very high reactivity and reversibility.

[0067] The above description of the disclosed embodiments enables one skilled in the art to make or use the application. Numerous modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for designing and fabricating silicon-based high-entropy alloys from photovoltaic silicon scrap by compensation method, characterized in that, The method comprises the following steps: (1) pretreating a silicon wafer cutting slurry to obtain silicon wafer cutting waste; (2) high-temperature refining the silicon wafer cutting waste and cooling in the furnace to obtain refined silicon ingot; (3) crushing the refined silicon ingot and melting with a solvent metal, and after the metal is completely melted, directional solidification is performed, and the furnace is cooled to obtain a silicon-based high-entropy alloy precursor; (4) cutting and separating the silicon-based high-entropy alloy precursor along the interface between the silicon-rich region and the silicon-based alloy to obtain a silicon-rich region for standby use; (5) preparing a target metal material according to the component proportions of the silicon-based high-entropy alloy; (6) melting the silicon-rich region and the target metal material, standing and heat preserving, and pouring into a mold, and cooling in the furnace to obtain the silicon-based high-entropy alloy.

2. A method for designing and preparing silicon-based high-entropy alloys from photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (1), the silicon wafer cutting slurry is the unprocessed silicon-containing powder cutting waste liquid generated in the production cutting process of a single crystal silicon rod and / or a polycrystalline silicon rod.

3. A method for designing and preparing silicon-based high-entropy alloys from photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (1), the pretreatment comprises solid-liquid separation, dehydration and drying, and the conditions are oxygen isolation or inert gas.

4. A method for designing and preparing silicon-based high-entropy alloys using photovoltaic silicon waste by compensation method according to claim 1, characterized by, In step (2), the high-temperature refining device is an induction furnace or an electric arc furnace, the temperature is not lower than 1600 DEG C, the pressure is not higher than 50 Pa or inert gas is introduced under normal pressure, and the time is 0.5-3 h.

5. A method for designing and preparing silicon-based high-entropy alloys using photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (3), the solvent metal is at least one of aluminum, tin and copper.

6. [Rule 20.6] A method for designing and preparing a silicon-based high-entropy alloy from photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (3), the melting device is a directional solidification resistance furnace or a directional solidification induction furnace, the temperature is not lower than 1450 DEG C, the pressure is not higher than 50 Pa or inert gas is introduced under normal pressure, and the directional solidification time is 0.5-80 h.

7. [incorporated by reference (Rule 20.6) 24.06.2025] A method for designing and preparing silicon-based high-entropy alloys from photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (5), the target metal material is at least four of chromium, aluminum, iron, copper, tin, germanium, antimony, manganese, cobalt, nickel, gallium and niobium.

8. [incorporated by reference (Rule 20.6) 24.06.2025] A method for designing and preparing a silicon-based high-entropy alloy from photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (6), the melting device is an induction furnace or an electric arc furnace, the temperature is not lower than 1450 DEG C, the pressure is not higher than 50 Pa or inert gas is introduced under normal pressure.

9. [incorporated by reference (Rule 20.6) 24.06.2025] A method for designing and preparing silicon-based high-entropy alloys from photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (6), the standing and heat preserving time is 0.5-2.5 h.

10. [Rule 20.6] A method for designing and preparing a silicon-based high-entropy alloy from photovoltaic silicon scrap by compensation method according to claim 1, characterized in that, In step (6), the silicon-based high-entropy alloy is an Al-Cr-Cu-Fe-Si high-entropy alloy, an Nb-Al-Ga-Ge-Si-Sn high-entropy alloy or a Ge-Si-Sn-Cu-Fe-Sb high-entropy alloy, the atomic mass percentage of each element is 5%-35%, and the total atomic mass percentage of all elements is 100%.