A modified talcum powder, its preparation method and application

Abstract

The present invention belongs to the technical field of inorganic powder processing, and provides a modified talc powder, a preparation method and an application thereof. The method of the present invention obtains a high-silica talc ore with a high silica content through optical sorting and screening; then, through demagnetization treatment, the iron in the high-silica talc ore is removed to further improve the purity of the high-silica talc ore; a grinding aid is added to perform secondary grinding on the non-magnetic talc ore, which improves the grinding speed of the non-magnetic talc ore and reduces the agglomeration effect, facilitating subsequent surface modification; then, a modifier is used to perform surface modification on the fine talc powder, and a polymer organic layer is coated on the surface of the fine talc powder to improve the compatibility between the modified talc powder and EVA, thereby improving the modification effect on EVA. The modified talc powder obtained by the method provided by the present invention has a high silica content, a high activation degree, and good compatibility with EVA, and can be well applied to EVA foaming materials. In addition, the method provided by the present invention realizes the utilization of low-grade talc ore.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic powder processing, and particularly relates to a modified talc powder, a preparation method thereof, and an application thereof. Background Art

[0002] Talc powder is a white hydrophobic powder, belonging to the natural monoclinic system. Its main component is magnesium silicate hydrate, with MgO 31.7%, SiO 2 63.5%, and water 4.8%. Its molecular formula is Mg 3 [Si 4 O 10 (OH) 2 , with a hardness of 1 and a specific gravity of 2.7 - 2.8. Talc powder usually exists in the form of dense massive, lamellar, radial, and fibrous aggregates, and its appearance is colorless transparent or white, but it shows light green, light yellow, light brown, or even light red due to the presence of a small amount of impurities. Due to its excellent physical and chemical properties such as lubricity, anti - adhesion, good covering power, softness, good gloss, and high temperature resistance, talc powder has been widely used in industries such as cosmetics, medicine, papermaking, coatings, and shoe materials.

[0003] EVA foaming materials have good surface gloss and chemical stability, and have characteristics such as anti - aging, ozone - resistance, and non - toxicity; in addition, EVA high - foaming sheets also have good softness and elasticity. Therefore, EVA foaming materials are widely used in shoe materials (slippers, mid - soles of sports shoes). When talc powder is added to EVA shoe materials, it has the following characteristics: 1. Effectively reduce costs; 2. Can improve product performance, such as enhancing the rigidity of EVA shoe materials, increasing the impact strength, and improving the scratch - resistance performance; 3. Make the melt in the preparation process of EVA shoe materials have better fluidity and improve the processing performance; 4. Improve the molding rate in the preparation process of EVA shoe materials, increase the output of finished products, and reduce energy consumption; 5. Improve the melt strength of EVA foaming materials and prevent the merging of bubbles.

[0004] Since natural pure talc ore is rare, talc ore is often associated with other mineral impurities. Common associated minerals include pyrite, chlorite, magnesite, and calcite, resulting in very low purity of talc ore and little silica content. Many low - grade talc ores with silica content of 25% - 30% cannot be directly ground for use in industries such as shoe materials, plastics, and rubbers, causing waste of resources; in addition, the compatibility between talc powder directly ground from low - grade talc ore and EVA resin is relatively poor, and directly adding this type of talc powder to EVA resin is likely to cause various production problems due to compatibility issues. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a modified talc powder, a preparation method thereof, and an application thereof. The modified talc powder obtained by the method provided by the present invention has good compatibility with EVA.

[0006] To achieve the above-mentioned invention object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing modified talc powder from low-grade talc ore, comprising the following steps:

[0008] The low-grade talc ore is successively subjected to first crushing and optical sorting and screening to obtain high-silica talc ore;

[0009] The high-silica talc ore is successively subjected to first grinding and demagnetization treatment to obtain non-magnetic talc ore;

[0010] The non-magnetic talc ore and a grinding aid are mixed and subjected to second grinding to obtain fine talc powder;

[0011] The fine talc powder and a modifier are mixed and subjected to surface modification to obtain the modified talc powder;

[0012] Calculated as silicon dioxide, the mass percentage content of silicon in the low-grade talc ore is 25% - 30%;

[0013] The modifier includes a modification monomer, a solvent and a crosslinking agent.

[0014] Preferably, calculated as silicon dioxide, the mass percentage content of silicon in the high-silica talc ore is 48% - 50%.

[0015] Preferably, calculated as silicon dioxide and iron(III) oxide, the mass percentage content of silicon in the non-magnetic talc ore is 57% - 60%, and the mass percentage content of iron ≤ 0.5%.

[0016] Preferably, the grinding aid includes an alcohol, sodium polyacrylate and a coupling agent; the mass ratio of the alcohol, sodium polyacrylate and the coupling agent is 5 - 6:1 - 2:2 - 3.

[0017] Preferably, the mass of the grinding aid is 0.5‰ - 0.7‰ of the mass of the non-magnetic talc ore.

[0018] Preferably, the modification monomer includes methyl methacrylate, butyl acrylate and divinylbenzene; the mass ratio of methyl methacrylate, butyl acrylate and divinylbenzene is 12 - 15:3 - 5:1 - 2;

[0019] The solvent includes toluene or an ethyl acetate - absolute ethanol mixed solvent;

[0020] The crosslinking agent includes 2,2'-azobisisobutyronitrile and / or benzoyl peroxide.

[0021] Preferably, the mass ratio of the modification monomer and the solvent is 16 - 22:24 - 28;

[0022] The mass of the crosslinking agent is 0.2-0.5% of the total mass of the modified monomer and the solvent.

[0023] Preferably, the mass of the modifier is 6-10‰ of the mass of the fine talc powder.

[0024] The present invention also provides modified talc powder obtained by the method according to the above technical solution. Calculated as silicon dioxide, the mass percentage content of silicon in the modified talc powder is 57.88-59.10%; the activation degree is 94.9-97.4%.

[0025] The present invention also provides the application of the modified talc powder according to the above technical solution in an EVA foaming material.

[0026] The present invention provides a method for preparing modified talc powder from low-grade talc ore, comprising the following steps: successively performing first crushing and optical sorting and screening on the low-grade talc ore to obtain high-silica talc ore; successively performing first grinding and demagnetization treatment on the high-silica talc ore to obtain non-magnetic talc ore; mixing the non-magnetic talc ore with a grinding aid and performing second grinding to obtain fine talc powder; mixing the fine talc powder with a modifier and performing surface modification to obtain the modified talc powder; calculated as silicon dioxide, the mass percentage content of silicon in the low-grade talc ore is 25%-30%; the modifier includes a modified monomer, a solvent and a crosslinking agent. The method of the present invention obtains high-silica talc ore with a high silicon dioxide content through optical sorting and screening; then through demagnetization treatment, the iron in the high-silica talc ore is removed to further improve the purity of the high-silica talc ore; adding a grinding aid to perform second grinding on the non-magnetic talc ore can improve the grinding speed of the non-magnetic talc ore while reducing the agglomeration effect, facilitating subsequent surface modification; then using the modifier to perform surface modification on the fine talc powder to coat a polymer organic layer on the surface of the fine talc powder, improving the compatibility between the modified talc powder and EVA, and further improving the modification effect on EVA. The modified talc powder obtained by the method provided by the present invention has a high silicon dioxide content, a high activation degree, and good compatibility with EVA, and can be well applied to an EVA foaming material. In addition, the method provided by the present invention realizes the utilization of low-grade talc ore.

[0027] The present invention also provides modified talc powder obtained by the method according to the above technical solution. Calculated as silicon dioxide, the mass percentage content of silicon in the modified talc powder is 57.88-59.10%; the activation degree is 94.9-97.4%. The modified talc powder provided by the present invention has a high silicon dioxide content and a high activity.

[0028] The present invention also provides the application of the modified talc powder according to the above technical solution in an EVA foaming material. The modified talc powder obtained by the method provided by the present invention has a high silicon dioxide content, a high activation degree, and good compatibility with EVA, and can be well applied to an EVA foaming material. Detailed implementation mode

[0029] The present invention provides a method for preparing modified talc powder from low-grade talc ore, comprising the following steps:

[0030] The low-grade talc ore is successively subjected to first crushing and optical sorting and screening to obtain high-silica talc ore;

[0031] The high-silica talc ore is successively subjected to first grinding and demagnetization treatment to obtain non-magnetic talc ore;

[0032] The non-magnetic talc ore and a grinding aid are mixed and subjected to second grinding to obtain fine talc powder;

[0033] The fine talc powder and a modifier are mixed and subjected to surface modification to obtain the modified talc powder;

[0034] Calculated as silicon dioxide, the mass percentage content of silicon in the low-grade talc ore is 25% to 30%;

[0035] The modifier includes a modified monomer, a solvent and a crosslinking agent.

[0036] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0037] The present invention successively subjects the low-grade talc ore to first crushing and optical sorting and screening to obtain high-silica talc ore.

[0038] In the present invention, calculated as silicon dioxide, the mass percentage content of silicon in the low-grade talc ore is 25% to 30%.

[0039] Before the first crushing, the present invention preferably further includes cleaning; the cleaning reagent preferably includes water; the present invention does not specifically limit the number of cleaning times and the amount of the cleaning reagent, as long as the sediment impurities adhered to the surface of the low-grade talc ore can be removed.

[0040] In the present invention, the particle size of the first crushed material obtained by the first crushing is preferably 20 to 50 mm. In the present invention, the number of times of the first crushing is preferably 2 times.

[0041] In the present invention, the optical sorting and screening is preferably carried out in an optical sorter.

[0042] In the present invention, calculated as silicon dioxide, the mass percentage content of silicon in the high-silica talc ore is preferably 48% to 50%.

[0043] After obtaining the high-silica talc ore, the present invention successively subjects the high-silica talc ore to first grinding and demagnetization treatment to obtain non-magnetic talc ore.

[0044] In the present invention, the first grinding method is preferably a Raymond mill, and the particle size of the first ground material obtained by the first grinding is preferably such that the mass content of the powder with a particle size of 80 to 200 mesh is ≥ 90%. The present invention does not specifically limit the rotation speed and time of the first grinding, as long as the material with the specified particle size can be ground.

[0045] In the present invention, the demagnetization treatment is preferably carried out in a magnetic separator; the magnetic strength of the demagnetization treatment is preferably 7500 to 20000 Oersteds, and more preferably 10000 to 20000 Oersteds.

[0046] In the present invention, based on iron oxide, the mass percentage of iron in the non-magnetic talc ore is preferably ≤ 0.5%; based on silicon dioxide, the mass percentage of silicon is preferably 57% to 60%.

[0047] After obtaining the non-magnetic talc ore, the present invention mixes the non-magnetic talc ore and a grinding aid, and performs a second grinding to obtain fine talc powder.

[0048] In the present invention, the grinding aid preferably includes an alcohol, sodium polyacrylate, and a coupling agent; the mass ratio of the alcohol, sodium polyacrylate, and the coupling agent is preferably 5 to 6:1 to 2:2 to 3, and more preferably 6:2:2. In the present invention, the alcohol preferably includes one or more of ethylene glycol, diethylene glycol, and esterified alcohol, and more preferably ethylene glycol; the esterified alcohol preferably includes one or more of esterified alcohol HE-a, esterified alcohol HE-C, and esterified alcohol HE-F. In the present invention, the coupling agent preferably includes one or more of a titanate coupling agent, an aluminum-titanium composite coupling agent, and an aluminate coupling agent, and more preferably a titanate coupling agent. In the present invention, the titanate coupling preferably includes one or more of titanate coupling agent HY201, titanate coupling TC-F, and titanate coupling TC-130. In the present invention, the aluminum-titanium composite coupling agent preferably includes one or more of aluminum-titanium composite coupling agent JTW-1618, aluminum-titanium composite coupling agent OL-AT1618, and aluminum-titanium composite coupling agent HY-133. In the present invention, the aluminate coupling agent preferably includes one or more of aluminate coupling agent dl411, aluminate coupling agent GR-AL18, and aluminate coupling agent LS62.

[0049] In the present invention, the mass of the grinding aid is preferably 0.5‰ to 0.7‰ of the mass of the non-magnetic talc ore, and more preferably 0.6‰.

[0050] In the present invention, the rotation speed of the second grinding is preferably 3000 to 4000 rpm, and more preferably 3200 to 3800 rpm; the time is preferably 1 to 1.5 h.

[0051] In the present invention, the second grinding is preferably carried out in a ball mill, and the ball mill preferably has a fully ceramic inner lining. In the present invention, the medium for the second grinding is preferably zirconia.

[0052] In the present invention, the non-magnetic talc ore and the grinding aid are preferably independently conveyed to the ball mill by a conveyor belt for the second grinding; the feeding speed of the non-magnetic talc ore is preferably 1500 - 2000 kg / h, more preferably 1600 - 1900 kg / h, and still more preferably 1700 - 1800 kg / h; the feeding speed of the grinding aid is preferably 80 - 100 kg / h.

[0053] In the present invention, the particle size of the fine talc powder is preferably 2.5 - 3 μm.

[0054] After obtaining the fine talc powder, in the present invention, the fine talc powder and the modifier are mixed and surface-modified to obtain the modified talc powder.

[0055] In the present invention, the modifying monomers preferably include methyl methacrylate, butyl acrylate, and divinylbenzene; the mass ratio of methyl methacrylate, butyl acrylate, and divinylbenzene is preferably 12 - 15:3 - 5:1 - 2.

[0056] In the present invention, the solvent preferably includes toluene or an ethyl acetate - absolute ethanol mixed solvent, more preferably toluene; the volume ratio of ethyl acetate to absolute ethanol in the ethyl acetate - absolute ethanol mixed solvent is preferably 1:1.

[0057] In the present invention, the cross-linking agent preferably includes azobisisobutyronitrile and / or benzoyl peroxide, more preferably azobisisobutyronitrile.

[0058] In the present invention, the mass ratio of the modifying monomer to the solvent is preferably 16 - 22:24 - 28.

[0059] In the present invention, the mass of the cross-linking agent is preferably 0.2 - 0.5% of the total mass of the modifying monomer and the solvent, more preferably 0.3 - 0.4%.

[0060] In the present invention, the mass of the modifier is preferably 6 - 10‰ of the mass of the fine talc powder.

[0061] In the present invention, the temperature for mixing the fine talc powder and the modifier is preferably 70 - 75°C.

[0062] In the present invention, the temperature for the surface modification is preferably 75 - 85°C, more preferably 80°C; the time is preferably 2 h.

[0063] In the present invention, the surface modification is preferably carried out in a surface modification machine.

[0064] After the surface modification, the present invention preferably further includes evaporation, drying and sieving in sequence. In the present invention, although the absolute pressure of the evaporation is preferably 8 kPa and the temperature is ≥85 °C. The present invention does not specifically limit the operation of the parameters of the drying, as long as the material can be dried.

[0065] The present invention also provides modified talcum powder obtained by the method of the above technical solution. In the present invention, calculated as silicon dioxide, the mass percentage content of silicon in the modified talcum powder is preferably 57.88-59.10%; the activation degree is preferably 94.9-97.4%. In the present invention, the particle size of the modified talcum powder is 2.5-3 μm.

[0066] The present invention also provides the application of the modified talcum powder of the above technical solution in EVA foaming materials. The present invention does not specifically limit the dosage of the modified talcum powder in the EVA foaming material, and it can be set according to the reagent requirements.

[0067] The following combines examples to elaborate in detail on the talcum powder provided by the present invention, its preparation method and application, but they cannot be understood as limiting the protection scope of the present invention.

[0068] Example 1

[0069] A method for preparing modified talcum powder from low-grade talc ore, comprising the following steps:

[0070] The low-grade talc ore with a mass percentage of silicon of 25% - 30% calculated as silicon dioxide is washed and first crushed to obtain ore pieces sized 20 - 50 mm; the ore is conveyed by a conveyor belt to an optical separator for optical separation and screening, and the ore is screened based on different reflectivities of the ore to obtain a high-silicon talc ore with a mass percentage of silicon of 48% - 50% calculated as silicon dioxide; then the high-silicon talc ore is ground into a powder with a particle size of 80 - 200 mesh and a mass percentage > 90% using a Raymond mill; afterwards, it is demagnetized using a magnetic separator with a magnetic intensity of 7500 Oersteds to obtain non-magnetic talc ore (calculated as ferric oxide, the mass percentage of iron in the non-magnetic talc ore ≤ 0.5%; calculated as silicon dioxide, the mass percentage of silicon is 57% - 60%); the non-magnetic talc ore enters a ball mill with a fully ceramic inner lining at a feeding speed of 1800 kg / h, and fully zirconium beads are used, supplemented with a grinding aid (the mass ratio of alcohol (ethylene glycol), sodium polyacrylate, and coupling agent (titanate coupling agent HY201) is 6:2:2, the mass of the grinding aid is 0.5‰ of the mass of the non-magnetic talc ore, and the feeding speed of the grinding aid is 80 kg / h), and it is secondarily ground at 3200 rpm for 1.5 h to obtain fine talc powder with a particle size of 2.5 - 3.0 μm; the fine talc powder is pneumatically conveyed into a surface modifier, and while maintaining the temperature at 75 ± 5 °C, a modifier is continuously added (the mass ratio of methyl methacrylate (MMA), butyl acrylate (BA), divinylbenzene (DVB), toluene, and azobisisobutyronitrile is 14:5:1:26:0.18, and the mass of the modifier is 6‰ of the mass of the fine talc powder), and after the addition of the modifier is completed, surface modification is maintained at 80 ± 5 °C for 2 h; after surface modification, the solvent and unreacted substances are distilled off (absolute pressure is 8 kPa, temperature is not less than 85 °C), and then it is dried and sieved to obtain modified talc powder.

[0071] The GB / T19281 - 2014 method is used to measure the performance of the obtained modified talc powder, and the results are shown in Table 1.

[0072] Table 1 Detection results of different batches of modified talc powder obtained in Example 1

[0073]

[0074] Example 2

[0075] A method for preparing modified talc powder from low-grade talc ore, comprising the following steps:

[0076] The low-grade talc ore with a mass percentage of silicon of 25% - 30% calculated as silicon dioxide is washed and first crushed to obtain ore pieces sized 20 - 50 mm; the ore is conveyed by a conveyor belt to an optical separator for optical separation and screening, and the ore is screened based on different reflectivities of the ore to obtain high-silica talc ore with a mass percentage of silicon of 48% - 50% calculated as silicon dioxide; then the high-silica talc ore is ground into a powder with a particle size of 80 - 200 meshes by a Raymond mill, and the mass percentage of the powder is > 90%; then it is demagnetized by a magnetic separator with a magnetic intensity of 15,000 Oersteds to obtain non-magnetic talc ore (calculated as ferric oxide, the mass percentage of iron in the non-magnetic talc ore is ≤ 0.5%; calculated as silicon dioxide, the mass percentage of silicon is 57% - 60%); the non-magnetic talc ore enters a ball mill with a fully ceramic inner lining at a feeding speed of 1800 kg / h, and fully zirconium beads are used, supplemented with a grinding aid (the mass ratio of alcohol (ethylene glycol), sodium polyacrylate and coupling agent (titanate coupling agent HY201) is 6:2:2, the mass of the grinding aid is 0.6‰ of the mass of the non-magnetic talc ore, and the feeding speed of the grinding aid is 80 kg / h), and it is ground for the second time at 3200 rpm for 1.5 h to obtain fine talc powder with a particle size of 2.5 - 3.0 μm; the fine talc powder is conveyed by wind to a surface modifier, and under the condition of maintaining the temperature at 75 ± 5 °C, a modifier is continuously added (the mass ratio of methyl methacrylate (MMA), butyl acrylate (BA), divinylbenzene (DVB), toluene, and azobisisobutyronitrile is 14:5:1:26:0.18, and the mass of the modifier is 8‰ of the mass of the fine talc powder), and after the addition of the modifier is completed, surface modification is maintained at 80 ± 5 °C for 2 h; after surface modification, the solvent and unreacted substances are distilled off (the absolute pressure is 8 kPa, and the temperature is not less than 85 °C), and then it is dried and sieved to obtain modified talc powder.

[0077] The performance of the obtained modified talc powder is measured by the method of GB / T19281 - 2014, and the results are shown in Table 2.

[0078] Table 2 Detection results of different batches of modified talc powder obtained in Example 2

[0079]

[0080] Example 3

[0081] A method for preparing modified talc powder using low-grade talc ore, comprising the following steps:

[0082] Low-grade talc ore with a silicon mass percentage of 25% - 30% calculated as silicon dioxide is washed and first crushed to obtain ore pieces sized 20 - 50 mm; the ore is conveyed by a conveyor belt to an optical separator for optical separation and screening, and the ore is screened based on different reflectivities of the ore to obtain high-silicon talc ore with a silicon mass percentage of 48% - 50% calculated as silicon dioxide; then the high-silicon talc ore is ground into a powder with a particle size of 80 - 200 mesh by a Raymond mill, and the mass percentage of the powder is > 90%; then it is demagnetized by a magnetic separator with a magnetic strength of 20,000 oersteds to obtain non-magnetic talc ore (calculated as iron(III) oxide, the iron mass percentage in the non-magnetic talc ore is ≤ 0.5%; calculated as silicon dioxide, the silicon mass percentage is 57% - 60%); the non-magnetic talc ore enters a ball mill with a fully ceramic lining at a feeding speed of 1800 kg / h, using fully zirconium beads, supplemented with a grinding aid (the mass ratio of alcohol (ethylene glycol), sodium polyacrylate, and coupling agent (titanate coupling agent HY201) is 6:2:2, the mass of the grinding aid is 0.7‰ of the mass of the non-magnetic talc ore, and the feeding speed of the grinding aid is 80 kg / h), and is secondarily ground at 3500 rpm for 1.2 h to obtain fine talc powder with a particle size of 2.5 - 3.0 μm; the fine talc powder is pneumatically conveyed to a surface modifier, and while maintaining the temperature at 75 ± 5 °C, a modifier is continuously added (the mass ratio of methyl methacrylate (MMA), butyl acrylate (BA), divinylbenzene (DVB), toluene, and azobisisobutyronitrile is 14:5:1:26:0.18, and the mass of the modifier is 10‰ of the mass of the fine talc powder), and after the addition of the modifier is completed, surface modification is maintained at 80 ± 5 °C for 2 h; after surface modification, the solvent and unreacted substances are distilled off (absolute pressure is 8 kPa, temperature is not less than 85 °C), and then it is dried and sieved to obtain modified talc powder.

[0083] The properties of the obtained modified talc powder were determined by the method of GB / T19281 - 2014, and the results are shown in Table 3.

[0084] Table 3 Detection results of different batches of modified talc powder obtained in Example 3

[0085]

[0086] It can be seen from Tables 1 - 3 that: the silicon content (calculated as silicon dioxide) of the obtained modified talc powder has been significantly increased, all increased to more than 57.88%, and the increase in silicon content is beneficial to improving the rigidity, impact strength, and scratch resistance of EVA foaming materials; the activation degrees have all reached more than 94.9%, and the higher the activation degree, the better the compatibility between the modified talc powder and EVA, effectively improving production efficiency, enhancing product quality, and reducing the defective rate of products.

[0087] Comparative Example 1

[0088] The difference from Example 1 is that divinylbenzene is omitted from the modifying monomers in the modifier.

[0089] Comparative Example 2

[0090] The difference from Example 1 is that butyl acrylate is omitted from the modifying monomers in the modifier.

[0091] Comparative Example 3

[0092] The difference from Example 1 is that the mass of the modifier is 12‰ of the mass of the fine talc powder.

[0093] Comparative Example 4

[0094] The difference from Example 1 is that the mass of the modifier is 2‰ of the mass of the fine talc powder.

[0095] The properties of the modified talc powders obtained in Comparative Examples 1 to 4 were measured by the method of GB / T19281-2014, and the results are shown in Table 4.

[0096] Table 4 Detection results of the modified talc powders obtained in Comparative Examples 1 to 4

[0097]

[0098] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing modified talc powder from low-grade talc ore, characterized in that, it comprises the following steps: Sequentially subject the low-grade talc ore to first crushing and optical sorting and screening to obtain high-silica talc ore; Sequentially subject the high-silica talc ore to first grinding and demagnetization treatment to obtain non-magnetic talc ore; Mix the non-magnetic talc ore with a grinding aid and perform second grinding to obtain fine talc powder; the grinding aid includes alcohol, sodium polyacrylate and a coupling agent; the mass ratio of the alcohol, sodium polyacrylate and the coupling agent is 5-6:1-2:2-3; the mass of the grinding aid is 0.5‰-0.7‰ of the mass of the non-magnetic talc ore; the alcohol includes one or more of ethylene glycol, diethylene glycol and esterified alcohol, and the coupling agent includes one or more of titanate coupling agent, aluminum-titanium composite coupling agent and aluminate coupling agent; Mix the fine talc powder with a modifier and perform surface modification to obtain the modified talc powder; Based on silicon dioxide, the mass percentage content of silicon in the low-grade talc ore is 25%-30%; Based on silicon dioxide, the mass percentage content of silicon in the high-silica talc ore is 48%-50%; The modifier includes a modified monomer, a solvent and a cross-linking agent; The modified monomer includes methyl methacrylate, butyl acrylate and divinylbenzene; the mass ratio of methyl methacrylate, butyl acrylate and divinylbenzene is 12-15:3-5:1-2; the cross-linking agent includes azobisisobutyronitrile and / or benzoyl peroxide; the mass ratio of the modified monomer and the solvent is 16-22:24-28; the mass of the cross-linking agent is 0.2-0.5% of the total mass of the modified monomer and the solvent; the mass of the modifier is 6-10‰ of the mass of the fine talc powder.

2. The method according to claim 1, characterized in that, Based on silicon dioxide and iron(III) oxide, the mass percentage content of silicon in the non-magnetic talc ore is 57%-60%, and the mass percentage content of iron ≤ 0.5%.

3. The method according to claim 1, characterized in that, The solvent includes toluene or an ethyl acetate-anhydrous ethanol mixed solvent.

4. The modified talc powder obtained by the method according to any one of claims 1 to 3, characterized in that, Based on silicon dioxide, the mass percentage content of silicon in the modified talc powder is 57.88%-59.10%; the activation degree is 94.9%-97.4%.

5. Use of the modified talc powder according to claim 4 in an EVA foaming material.

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