Method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting

Abstract

The present invention discloses a method for removing silicon dioxide from the surface of silicon powder cut by diamond wire cutting, which is specifically implemented according to the following steps: step 1, filter the waste material cut by diamond, vacuum dry the solid obtained by filter pressing to obtain a dry sample, weigh the carbon precursor and the dry sample and mix them in deionized water or ethanol, and place the mixed solution in a water bath stirring pot for pre-curing, dry it after pre-curing, grind and sieve it to obtain an initial sample; step 2, place the initial sample obtained in step 1 in a high-temperature heating device for heating and heat preservation, pyrolyze the carbon precursor into amorphous carbon and coat it on the initial sample, and then heat it to a preset temperature for heat preservation, remove silicon dioxide, and obtain pure silicon powder. The method for removing silicon dioxide from the surface of silicon powder cut by diamond wire cutting of the present invention uses a carbon precursor to provide a carbon source, forms a coating layer on the surface of silicon powder, and removes silicon dioxide by carbon thermal reaction to obtain pure silicon powder.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic materials, and in particular relates to a method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting. Background Art

[0002] The diamond wire cutting process is a kind of multi-wire cutting technology, which was developed to improve the mortar silicon carbide cutting process. In the diamond wire cutting process, a steel wire with a uniform surface coating of fine diamond particles is required. The wire wheel rotates forward and reverse quickly and rhythmically to achieve the reciprocating motion of the steel wire. The blade material involved in the cutting rubs against the silicon material, and the silicon material is cut into more than 2,000 pieces at a time. The cutting process will produce about 40% of cutting waste. The silicon content in the cutting waste is extremely high and the powder particle size is fine. If it is directly discharged without treatment, it will not only cause a waste of silicon resources, but also cause pollution to the environment. According to statistics, in 2023, my country's polysilicon production will be about 1.43 million tons, silicon wafer production will be 622GW, national crystalline silicon battery production will be 545 GW, and national crystalline silicon module production will exceed 499 GW. my country's photovoltaic industry still maintains a vigorous development momentum, and the output of cutting waste has also increased year by year with the output and consumption of crystalline silicon. If high-purity silicon can be effectively recycled from cutting waste, it will not only greatly save production costs, but also reduce environmental pollution and waste of raw materials caused by direct waste discharge. The main components of cutting waste include crystalline silicon, silicon dioxide and metal impurities. Due to the high specific surface area of ​​silicon powder and its easy oxidation during cutting and storage, amorphous silicon dioxide is generated on the outer surface of silicon powder. Ordinary mechanical separation or magnetic separation cannot separate the two. The removal of silicon dioxide on the surface of silicon powder has become a major problem in the recycling of cutting waste.

[0003] In current research at home and abroad, the patent name is a method for purifying silicon waste to prepare high-purity silicon, and the application number is CN200810058570.0. This patent uses vacuum evaporation and directional condensation to refine and purify silicon waste, remove metal and non-metallic impurities in silicon waste, and finally obtain high-purity silicon. However, its process is relatively complicated and the instrument cost is high, which is not conducive to large-scale production. At the same time, the energy consumption required for high-temperature treatment is high, which does not conform to the current concepts of "green" and "environmental protection". The patent name is a method for preparing high-purity silicon using silicon cutting waste, and the application number is CN202011458320.3. This patent mixes silicon cutting waste, slag-making agent and fluorine-free and chlorine-free slag, and performs slag refining in an inert atmosphere. After slag silicon separation, block silicon and fluorine-free and chlorine-free residue are obtained. The use of slag-making agent brings new costs to the enterprise, and the slag-making efficiency and the amount of slag-making agent used need to be considered. At the same time, the temperature required for silicon oxide separation and melting is high, and the process energy consumption is large. In order to avoid the high energy consumption problem caused by the separation of silicon oxide, some scientific researchers use acid pickling to remove the silicon oxide layer on the surface of silicon powder. The acid leaching method has low energy consumption, simple operation, and can leach most of the metal impurities in the waste. The patent name is a method for preparing high-quality silicon carbide using waste silicon micropowder, and the application number is CN201910213152.2. This patent uses different types of pickling solutions-hydrochloric acid, sulfuric acid, hydrofluoric acid, one or more combinations of two or more to remove metal impurities and silicon oxide in the obtained sample. However, a large amount of wastewater and waste residue will be generated during the acid leaching process, which is complicated and difficult to handle, and is easy to cause certain pollution to the environment. In addition, the acid leaching impurity removal process cannot completely remove non-metallic impurities such as boron, phosphorus, and silicon oxide in diamond cutting waste, and the purity of the obtained product cannot reach the level of chemical silicon; the patent name is a method for preparing 6N high-purity silicon using cutting silicon waste, and the application number is CN202210568885.X. This patent uses a metal thermal reduction method to in-situ reduce the oxide layer on the surface of cutting silicon waste. However, the large amount of metal reducing agents used and the high cost are not conducive to enterprise production, and they are prone to introduce new impurities into the obtained samples.

[0004] In summary, the current research status cannot meet the requirements of achieving high impurity removal rate and realizing industrialization at the same time, saving production costs and bringing extremely high economic benefits. At the same time, the silicon oxide impurities contained in the silicon powder remain on the surface of the silicon powder in a combined manner, and it is difficult to completely remove them by conventional acid leaching impurity removal and high-temperature melting processes. How to remove the surface silicon dioxide and realize the high added value of silicon powder under the premise of green environmental protection is a problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting, using a carbon precursor to provide a carbon source, forming a coating layer on the surface of the silicon powder, and removing silicon dioxide by carbon thermal reaction to obtain pure silicon powder.

[0006] The technical solution adopted by the present invention is a method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting, which is specifically implemented according to the following steps:

[0007] Step 1, filter the waste material removed by diamond cutting, vacuum dry the solid obtained by filter pressing to obtain a dry sample, weigh the carbon precursor and the dry sample, mix them in deionized water or ethanol, and place the mixed solution in a water bath stirring pot for pre-curing, and dry and grind and sieve after pre-curing to obtain an initial sample;

[0008] Step 2, placing the initial sample obtained in step 1 into a high-temperature heating device for heating and heat preservation, pyrolyzing the carbon precursor into amorphous carbon coating the initial sample, and then heating to a preset temperature for heat preservation, removing silicon dioxide, and obtaining pure silicon powder.

[0009] The technical solution of the present invention is also characterized in that:

[0010] The specific calculation formula for the amount of carbon precursor weighed in step 1 is:

[0011] (1);

[0012] In the formula, m CP is the mass of carbon precursor, K is the residual carbon rate of carbon precursor, M SiO2 is the relative atomic mass of silicon dioxide, M C is the relative atomic mass of carbon, m SiO2 is the mass of silicon dioxide.

[0013] The vacuum drying temperature in step 1 is 50-70°C, and the vacuum drying time is 10 h.

[0014] In step 1, the pre-curing temperature is 50-70°C and the drying temperature is 100-120°C.

[0015] The mesh size of the dried sample in step 1 is 200 mesh and the particle size is 75 μm.

[0016] The waste material of the dried sample in step 1 has a moisture content of less than 5% and a silicon dioxide content of 5%-30%.

[0017] In step 2, the heating and holding temperature is 800-900°C, the holding time is 2-3 h, and the heating rate is 5-10°C / min.

[0018] In step 2, the preset temperature is 1200-1500 °C, the holding time is 3-5 h, and the heating rate is 3-5 °C / min.

[0019] In step 1, the carbon precursor is a mixture of one or more of phenolic resin, glucose, starch or sugar alcohol.

[0020] The beneficial effects of the present invention are:

[0021] The method for removing silicon dioxide from the surface of diamond wire-cut silicon powder provided by the present invention adopts diamond wire-cut waste as raw material, which has low cost and high purity, and reduces the pollution of waste treatment. A carbon precursor is selected as a carbon source, which provides raw materials for carbon thermal reduction reaction after pyrolysis, and the amorphous free carbon after pyrolysis is distributed between each powder grain, hindering the diffusion path of the grains, reducing agglomeration, and making the grains smaller. At the same time, carbon coating is combined with carbon thermal reduction reaction to remove silicon dioxide, and more CO, CO2, and SiO gases are generated in the reaction, which makes the reaction out of equilibrium, promotes the reaction to proceed in the forward direction, and reduces the reaction temperature requirement. Compared with directional solidification and arc granulation assisted vacuum melting technology, it has lower energy consumption, simpler and more convenient process, and is suitable for large-scale production in factories. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic flow diagram of a method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting of the present invention;

[0023] Figure 2 is an XRD schematic diagram of silicon powder obtained by removing silicon dioxide in Example 3 of the present invention;

[0024] Figure 3 is a SEM schematic diagram of the initial sample coated with the carbon precursor in Example 3 of the present invention;

[0025] Figure 4 This is a SEM schematic diagram at 1000 times magnification of silicon powder obtained by removing silicon dioxide in Example 3 of the present invention;

[0026] Figure 5 This is a SEM schematic diagram at 2000 times magnification of silicon powder obtained by removing silicon dioxide in Example 3 of the present invention;

[0027] Figure 6 This is a SEM schematic diagram at 5000 times magnification of the silicon powder obtained by removing silicon dioxide in Example 3 of the present invention. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The present invention provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting, such as Figure 1 As shown, the specific implementation steps are as follows:

[0030] Step 1, filter the waste material removed by diamond cutting, vacuum dry the solid obtained by filter pressing to obtain a dry sample, weigh the carbon precursor and the dry sample, mix them in deionized water or ethanol, and place the mixed solution in a water bath stirring pot for pre-curing, and dry and grind and sieve after pre-curing to obtain an initial sample;

[0031] Among them, the specific calculation formula for the weighing amount of the carbon precursor in step 1 is:

[0032] (1);

[0033] In the formula, m CP is the mass of carbon precursor, K is the residual carbon rate of carbon precursor, M SiO2 is the relative atomic mass of silicon dioxide, M C is the relative atomic mass of carbon, m SiO2 is the mass of silicon dioxide.

[0034] In step 1, the vacuum drying temperature is 50-70°C, the vacuum drying time is 10 h, the pre-curing temperature is 50-70°C, the drying temperature is 100-120°C, the mesh size of the dried sample is 200 mesh, the particle size is 75 μm, the moisture content of the dried sample waste is less than 5%, and the silicon dioxide content is 5%-30%; the carbon precursor is a mixture of one or more of phenolic resin, glucose, starch or sugar alcohol.

[0035] Step 2, placing the initial sample obtained in step 1 into a high-temperature heating device for heating and heat preservation, pyrolyzing the carbon precursor into amorphous carbon coating the initial sample, and then heating to a preset temperature for heat preservation, removing silicon dioxide, and obtaining pure silicon powder.

[0036] In step 2, the heating and holding temperature is 800-900 °C, the holding time is 2-3 h, the heating rate is 5-10 °C / min, the preset temperature is 1200-1500 °C, the holding time is 3-5 h, and the heating rate is 3-5 °C / min.

[0037] Example 1

[0038] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0039] Step 1, filter the obtained waste material, vacuum dry the separated solid at 50°C, grind and sieve to obtain a dry sample after drying for 10 hours, the moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh 0.5 g of phenolic resin and dissolve it in 20 ml of ethanol solution, add 5 g of dry sample to mix, place it in a water bath stirring pot at 50°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 100°C for curing, then grind and sieve to obtain an initial sample.

[0040] Step 2, placing the initial sample obtained in step 1 into a high-temperature tube furnace and heating it to 800 °C for pyrolysis, the holding time is 3 h, the heating rate is 5 °C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1200 °C for carbon thermal reduction, the heating rate is 3 °C / min, and after the holding time is 3 h, the silicon dioxide is removed by carbon thermal reduction to obtain pure silicon powder.

[0041] Example 2

[0042] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0043] Step 1, filter the obtained waste material, vacuum dry the separated solid at 60°C, grind and sieve to obtain a dry sample after drying for 10 hours, the moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh a total of 0.5 g of a mixture of phenolic resin and glucose and dissolve it in 20 ml of ethanol solution, add 5 g of the dry sample to mix, place it in a water bath stirring pot at 60°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 110°C for curing, then grind and sieve to obtain an initial sample.

[0044] Step 2, placing the initial sample obtained in step 1 in a high-temperature tube furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1300 ° C for carbon thermal reduction, the heating rate is 3 ° C / min, and after the holding time is 4 h, carbon thermal reduction is used to remove silicon dioxide to obtain pure silicon powder.

[0045] Example 3

[0046] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, and the specific steps are as follows:

[0047] Step 1, filter the obtained waste material, vacuum dry the separated solid at 70°C, grind and sieve to obtain a dry sample after drying for 10 hours, the moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh 0.5 g of starch and dissolve it in 20 ml of ethanol solution, add 5 g of dry sample to mix, place it in a water bath stirring pot at 70°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 120°C for curing, then grind and sieve to obtain an initial sample.

[0048] Step 2, placing the initial sample obtained in step 1 in a high-temperature tube furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1300 ° C for carbon thermal reduction, the heating rate is 3 ° C / min, and after the holding time is 4 h, carbon thermal reduction is used to remove silicon dioxide to obtain pure silicon powder.

[0049] in, Figure 2 XRD pattern of pure silicon powder obtained by removing silicon dioxide; Figure 3 is the SEM image of the sample coated with carbon precursor; Figure 2 It can be seen that the obtained sample phase diagram is pure elemental silicon; Figure 3 It can be seen that there are carbon particles on the surface of the initial sample, combined with the sample composition changes in Table 1, it proves that the carbon is successfully coated. Figure 4-6 It can be seen that pure silicon powder was successfully prepared.

[0050] Example 4

[0051] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0052] Step 1, filter the obtained waste material, vacuum dry the separated solid at 70°C, grind and sieve to obtain a dry sample after drying for 10 hours, the waste material moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh 0.5 g of sugar alcohol and dissolve it in 20 ml of ethanol solution, add 5 g of dry sample to mix, place it in a water bath stirring pot at 70°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 120°C for curing, then grind and sieve to obtain an initial sample.

[0053] Step 2, placing the initial sample obtained in step 1 into a high-temperature tubular furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1300 ° C for carbon thermal reduction, the heating rate is 4 ° C / min, and after the holding time is 4 h, the carbon thermal reduction removes silicon dioxide to obtain pure silicon powder.

[0054] Example 5

[0055] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0056] Step 1, filter the obtained waste material, vacuum dry the separated solid at 70°C, grind and sieve to obtain a dry sample after drying for 10 hours, the waste material moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh a total of 1.5 g of a mixture of sugar alcohol and starch and dissolve it in 20 ml of ethanol solution, add 5 g of the dry sample to mix, place it in a water bath stirring pot at 70°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 120°C for curing, then grind and sieve to obtain an initial sample.

[0057] Step 2, placing the initial sample obtained in step 1 in a high-temperature tubular furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1500 ° C for carbon thermal reduction, the heating rate is 5 ° C / min, after the holding time is 5 h, the carbon thermal reduction removes silicon dioxide to obtain pure silicon powder.

[0058] Example 6

[0059] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0060] Step 1, filter the obtained waste material, vacuum dry the separated solid at 70°C, grind and sieve to obtain a dry sample after drying for 10 hours, the moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh 3 g of glucose and dissolve it in 20 ml of ethanol solution, add 5 g of dry sample to mix, place it in a water bath stirring pot at 70°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 120°C for curing, then grind and sieve to obtain an initial sample.

[0061] Step 2, placing the initial sample obtained in step 1 in a high-temperature tubular furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1500 ° C for carbon thermal reduction, the heating rate is 5 ° C / min, after the holding time is 5 h, the carbon thermal reduction removes silicon dioxide to obtain pure silicon powder.

[0062] Example 7

[0063] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0064] Step 1, filter the obtained waste material, vacuum dry the separated solid at 70°C, grind and sieve to obtain a dry sample after drying for 10 hours, the moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh a total of 3 g of a mixture of phenolic resin and starch and dissolve it in 20 ml of ethanol solution, add 5 g of the dry sample to mix, place it in a water bath stirring pot at 70°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 120°C for curing, then grind and sieve to obtain an initial sample.

[0065] Step 2, placing the initial sample obtained in step 1 in a high-temperature tubular furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1500 ° C for carbon thermal reduction, the heating rate is 5 ° C / min, after the holding time is 5 h, the carbon thermal reduction removes silicon dioxide to obtain pure silicon powder.

[0066] Example 8

[0067] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0068] Step 1, filter the obtained waste material, vacuum dry the separated solid at 70°C, grind and sieve to obtain a dry sample after drying for 10 hours, the moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh a total of 3 g of a mixture of glucose and starch and dissolve it in 20 ml of ethanol solution, add 5 g of the dry sample to mix, place it in a water bath stirring pot at 70°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 120°C for curing, then grind and sieve to obtain an initial sample.

[0069] Step 2, placing the initial sample obtained in step 1 in a high-temperature tubular furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1500 ° C for carbon thermal reduction, the heating rate is 5 ° C / min, after the holding time is 5 h, the carbon thermal reduction removes silicon dioxide to obtain pure silicon powder.

[0070] Example 9

[0071] This embodiment provides a method for removing silicon dioxide from the surface of silicon powder by diamond wire sawing, such as Figure 1 As shown, the specific steps are as follows:

[0072] Step 1, filter the obtained waste material, vacuum dry the separated solid at 70°C, grind and sieve to obtain a dry sample after drying for 10 hours, the moisture content of the dry sample is less than 5%, the silicon dioxide content is 5%-30%, the mesh size is 200 mesh, and the particle size is 75 μm; weigh a total of 3 g of a mixture of phenolic resin and sugar alcohol and dissolve it in 20 ml of ethanol solution, add 5 g of the dry sample to mix, place it in a water bath stirring pot at 70°C for pre-curing, and heat and stir for 3 hours; take it out and place it in a vacuum drying oven to dry at 120°C for curing, then grind and sieve to obtain an initial sample.

[0073] Step 2, placing the initial sample obtained in step 1 in a high-temperature tubular furnace and heating it to 850 ° C for pyrolysis, the holding time is 2 h, the heating rate is 7 ° C / min, so that the carbon precursor powder is pyrolyzed into amorphous carbon coated on the initial sample, and the temperature is raised to 1500 ° C for carbon thermal reduction, the heating rate is 5 ° C / min, after the holding time is 5 h, the carbon thermal reduction removes silicon dioxide to obtain pure silicon powder.

[0074] Table 1 Element contents inside the samples before and after coating in Example 3

[0075]

[0076] Table 2 Internal element content of pure silicon powder in different embodiments

[0077]

[0078] As shown in Table 1, the C content of the sample increased significantly before and after coating, indicating that the carbon precursor was successfully coated. As shown in Table 2, the contents of Si, O and C in the pure silicon powder obtained after removing silicon dioxide from Examples 1 to 9, it can be seen that the oxygen content in the sample powder in the implementation case was reduced to less than 2.5%, and SiO2 was basically removed. The method for removing silicon dioxide from the surface of diamond wire-cut silicon powder of the present invention removes silicon dioxide by carbon coating combined with carbon thermal reduction reaction, and generates more CO, CO2, and SiO gases in the reaction, so that the reaction is out of equilibrium, promotes the reaction to proceed in the forward direction, and reduces the reaction temperature requirement. Compared with directional solidification and arc granulation assisted vacuum melting technology, it has lower energy consumption, simpler and more convenient process, and is suitable for large-scale production in factories.

Claims

1. A method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting, characterized in that: Follow the steps below to implement it: Step 1, filter the waste material removed by diamond cutting, vacuum dry the solid obtained by filter pressing to obtain a dry sample, weigh the carbon precursor and the dry sample, mix them in deionized water or ethanol, and place the mixed solution in a water bath stirring pot for pre-curing, and dry and grind and sieve after pre-curing to obtain an initial sample; Step 2, placing the initial sample obtained in step 1 in a high-temperature heating device for heating and heat preservation, pyrolyzing the carbon precursor into amorphous carbon coating the initial sample, and then heating to a preset temperature for heat preservation, removing silicon dioxide, and obtaining pure silicon powder; The preset temperature in step 2 is 1200-1300°C, the holding time is 3-5 h, and the heating rate is 3-5°C / min.

2. The method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting according to claim 1, characterized in that: The vacuum drying temperature in step 1 is 50-70° C., and the vacuum drying time is 10 h.

3. The method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting according to claim 1, characterized in that: In step 1, the pre-curing temperature is 50-70°C, and the drying temperature is 100-120°C.

4. The method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting according to claim 1, characterized in that: The mesh size of the dried sample in step 1 is 200 mesh.

5. The method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting according to claim 1, characterized in that: The waste moisture content of the dried sample in step 1 is less than 5%, and the silicon dioxide content is 5%-30%.

6. The method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting according to claim 1, characterized in that: The heating and insulation temperature in step 2 is 800-900°C, the insulation time is 2-3 h, and the heating rate is 5-10°C / min.

7. The method for removing silicon dioxide from the surface of silicon powder by diamond wire cutting according to claim 1, characterized in that: The carbon precursor in step 1 is a mixture of one or more of phenolic resin, glucose, starch or sugar alcohol.

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