A kind of highly dispersed nano high-purity magnesium oxide powder and preparation method thereof

Abstract

The present invention provides a highly dispersed nanometer high-purity magnesium oxide powder and a preparation method thereof, and belongs to the field of magnesium oxide powder. The preparation method of the highly dispersed nanometer high-purity magnesium oxide powder adopts the following raw materials for preparation: alkyl magnesium chloride, reaction aid, surfactant, water; the alkyl magnesium chloride is at least one of the following: methyl magnesium chloride, ethyl magnesium chloride, cyclohexyl magnesium chloride; the reaction aid is at least one of the following: tetraethyl ammonium chloride, tetramethyl ammonium bromide, triethyl methyl ammonium chloride. The preparation method of the highly dispersed nanometer high-purity magnesium oxide powder of the present invention has a narrow powder particle size distribution, good preparation process stability, simple process, low production energy consumption, and low production cost; it can realize the integrated preparation of highly crystalline, highly dispersed, and high-purity nanometer magnesium oxide powder.

Description

Technical Field

[0001] The invention relates to the field of magnesium oxide powder, in particular to highly dispersed nanometer high-purity magnesium oxide powder and a preparation method thereof. Background Art

[0002] Existing nano magnesium oxide powders generally use magnesium chloride and urea as raw materials, and use chemical precipitation to obtain magnesium hydroxide, which is then washed with water, washed with alcohol, and replaced by water / alcohol azeotropic distillation, and then dried to obtain nano-grade magnesium hydroxide powder, which is then calcined at high temperature to obtain nano magnesium oxide powder. However, during its preparation process, the powder particle size distribution is wide; and the powder is very easy to agglomerate. After the nano magnesium oxide powder is hard agglomerated, it needs to be further finely ground with the help of fine grinding equipment to obtain a nano product, and the production process stability is poor.

[0003] Furthermore, the existing nano-magnesium oxide powder has the problem of low crystallinity. In the preparation process of nano-magnesium oxide powder, if a suitable reaction aid is not used, the nano-magnesium oxide powder prepared by chemical synthesis has many internal defects and low crystallinity.

[0004] Further, the existing chemical synthesis method of nano magnesium oxide powder still has the problems of poor continuity of production process, cumbersome process and high production cost, and it is impossible to realize the integrated preparation of high crystallization, high dispersion and high purity nano magnesium oxide powder. For the chemical synthesis method, it is necessary to consider how to improve the crystallinity and dispersibility of nano magnesium oxide powder at the same time during the preparation process. If the crystallization performance is low during the preparation process, high-purity nano magnesium oxide powder cannot be obtained; to overcome this defect, it is necessary to cooperate with high-temperature calcination during the preparation process to improve the crystallization performance of magnesium oxide powder, but during the high-temperature calcination process, the particles of magnesium oxide powder will increase and lose the original nano characteristics, and it is necessary to further use grinding equipment to restore nano-ization, the preparation process is cumbersome, the production cycle is long, and the production cost and production energy consumption are high. At the same time, if the dispersibility of magnesium oxide powder is poor during the preparation process, it is usually necessary to use grinding equipment with solvents, dispersing aids and means to carry out nano high dispersion, which further greatly increases the production cost and production energy consumption.

[0005] Therefore, in view of the above-mentioned technical defects, an integrated preparation method for highly crystalline, highly dispersed, and high-purity nano-magnesium oxide powder is provided, which has a narrow powder particle size distribution, good preparation process stability, a simple process, low production energy consumption, and low production cost, which has important technical significance. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a highly dispersed nano high-purity magnesium oxide powder and a preparation method thereof. The nano high-purity magnesium oxide powder has a narrow powder particle size distribution, good preparation process stability, a simple process, low production energy consumption, and low production cost; and can realize the integrated preparation of highly crystalline, highly dispersed, and high-purity nano magnesium oxide powder.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing highly dispersed nano high-purity magnesium oxide powder, using the following raw materials for preparation: alkyl magnesium chloride, reaction aid, surfactant, water;

[0009] The alkyl magnesium chloride is at least one of the following: methyl magnesium chloride, ethyl magnesium chloride, cyclohexyl magnesium chloride;

[0010] The reaction aid is at least one of the following: tetraethylammonium chloride, tetramethylammonium bromide, triethylmethylammonium chloride;

[0011] The surfactant is at least one of the following: polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer P123, polyoxyethylene-polyoxypropylene ether block copolymer F127, octadecyl trimethyl ammonium bromide;

[0012] The water is not particularly limited and can be tap water or deionized water.

[0013] The preparation method of the highly dispersed nano high-purity magnesium oxide powder comprises the following steps: a surfactant is uniformly dispersed in water to form spherical micelles, alkyl magnesium chloride is added, the surface of the spherical micelles is coated with alkyl, magnesium ions penetrate into the spherical micelles, and then Mg(OH) is formed under the action of a reaction aid. x (CO) y (NH2) z -R, spherical Mg(OH) is obtained by drying x (CO) y (NH2) z -R powder, and then calcined to obtain highly dispersed nano high-purity magnesium oxide powder.

[0014] The spherical Mg(OH) x (CO) y (NH2) z -R powder, x is 1, y is 1, z is any number from 1 to 3, and R is an alkyl group; preferably, x is 1, y is 1, and z is any number from 1 to 2.

[0015] The alkyl group is methyl or ethyl.

[0016] Among them, the reaction aid used can bond with magnesium ions in aqueous solution to form Mg(OH) x (NH) y At the same time, the alkyl group methyl in alkyl magnesium chloride can x (NH) y Hydrophobic surface functional groups are formed on the surface, and repulsion is generated between them; thus, in the subsequent drying and calcination process, the high dispersibility of the single-particle powder can be maintained, and finally a highly dispersed nano-high-purity magnesium oxide powder is obtained. Furthermore, the long-chain surfactant used can form continuous spherical micelles in water, and the magnesium ions are enriched inside the spherical micelles, and the negative ions are directed outward, which is conducive to the subsequent reaction with the reaction aid.

[0017] Furthermore, the mass ratio of the alkyl magnesium chloride to water is 35-55:45-65.

[0018] The amount of surfactant used is 0.01-0.15% of the mass of alkyl magnesium chloride;

[0019] The dosage of the reaction aid is 0.5-3% of the mass of the alkyl magnesium chloride.

[0020] The method for preparing highly dispersed nano high-purity magnesium oxide powder comprises the following steps:

[0021] Step S001, adding a surfactant to water at a temperature of 60-80°C, further adding alkyl magnesium chloride under high-speed stirring conditions of 1000 r / min or more, mixing and stirring for 0.5 h or more, standing and cooling for 2 h or more, to obtain a transparent low-viscosity slurry with a viscosity of 400-500 Pa·s.

[0022] Step S002, adding a reaction aid to the transparent low-viscosity slurry, mixing and stirring for 0.5 h or more at a temperature of 60-80° C. under high-speed stirring conditions of 1000 r / min or more to obtain a white uniform solution, and letting it stand for 1 h or more to obtain a white precipitate slurry.

[0023] Step S003, after centrifuging the white precipitate slurry, wash the solid matter with water for 2-3 times to obtain a white precipitate.

[0024] Step S004, in a normal pressure environment, control the baking temperature to be 75-95° C., bake the white precipitate for 5 hours or more to obtain a white single powder.

[0025] Step S005, calcining the white single powder, controlling the calcination heating rate to 2-2.5°C / min, heating to 900-1300°C, and calcining for 3 hours to obtain highly dispersed nano high-purity magnesium oxide powder.

[0026] A highly dispersed nanometer high-purity magnesium oxide powder, wherein the particles of the magnesium oxide powder have a highly densified nearly spherical structure; the particle size d50 of the highly dispersed nanometer high-purity magnesium oxide powder is 20-35nm, the magnesium oxide content is ≥99.9wt%, the crystallinity is >99%, and the pH value is ≤10.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The method for preparing highly dispersed nano-high purity magnesium oxide powder of the present invention comprises the following steps: using alkyl magnesium chloride, a reaction aid and a surfactant, wherein the surfactant is uniformly dispersed in water to form spherical micelles, and then alkyl magnesium chloride is added. The surface of the spherical micelles is coated with alkyl groups, and magnesium ions penetrate into the spherical micelles. Then, under the action of the reaction aid, Mg(OH) x (CO) y (NH2) z -R, spherical Mg(OH) is obtained by drying x (CO) y (NH2) z -R powder, and then calcining to obtain highly dispersed nano high-purity magnesium oxide powder; the prepared nano high-purity magnesium oxide powder has a narrow powder particle size distribution, good preparation process stability, simple process, low production energy consumption, and low production cost; it can achieve the integrated preparation of high-crystallization, high-dispersion, and high-purity nano magnesium oxide powder.

[0029] (2) The method for preparing highly dispersed nano-sized high-purity magnesium oxide powder of the present invention can effectively avoid the problems of wide powder particle size distribution, easy powder agglomeration and poor process stability in the existing magnesium oxide powder preparation process; the production process has good continuity and a simple process, and can simultaneously improve the crystallinity and dispersibility of the magnesium oxide powder while effectively avoiding the problem of magnesium oxide powder particles increasing and losing their original nano properties during the calcination process. There is no need to use grinding equipment to restore nano-size after calcination, which effectively simplifies the process flow and shortens the production cycle; further, the preparation method of the present invention can obtain highly dispersed nano-sized magnesium oxide powder in one step, without the problem of powder agglomeration during the preparation process, and there is no need to use grinding equipment in combination with solvents and dispersing aids after calcination to carry out high dispersion treatment of nano-sized powders, which further greatly reduces production costs and energy consumption.

[0030] (3) The method for preparing highly dispersed nano-high purity magnesium oxide powder of the present invention has a simple process flow. Compared with magnesium oxide powder prepared by the existing process, the production cost per unit mass of nano-magnesium oxide powder is reduced by more than 90%; and the highly crystalline and highly dispersed nano-scale magnesium oxide powder that can be prepared in one step has high powder purity, few impurities, and a magnesium oxide content of more than 99.9wt%.

[0031] (4) The highly dispersed nano-high purity magnesium oxide powder of the present invention has a particle size d50 of 20-35 nm, a magnesium oxide content ≥99.9wt%, a crystallinity of >99%, a pH value ≤10, no agglomeration during the preparation and subsequent application process, and high dispersibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is an electron microscope photograph of the highly dispersed nano-high purity magnesium oxide powder prepared in Example 1. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described.

[0034] Example 1

[0035] like Figure 1 As shown, this embodiment provides a highly dispersed nano high-purity magnesium oxide powder, and the specific specifications are shown in Table 1:

[0036] Table 1 Specific specifications of highly dispersed nano high purity magnesium oxide powder of Example 1

[0037]

[0038] The highly dispersed nanometer high-purity magnesium oxide powder is prepared from the following raw materials: alkyl magnesium chloride, reaction aid, surfactant and water.

[0039] The alkyl magnesium chloride is ethyl magnesium chloride.

[0040] The reaction aid is tetraethylammonium chloride.

[0041] The surfactant is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer P123.

[0042] Wherein, the mass ratio of alkyl magnesium chloride to water is 40:60.

[0043] The amount of surfactant used is 0.1% of the mass of alkyl magnesium chloride;

[0044] The dosage of the reaction aid is 1.5% of the mass of the alkyl magnesium chloride.

[0045] Specifically, the specific weight portions of the above raw materials are as follows:

[0046] 40 parts of ethyl magnesium chloride;

[0047] 60 parts of water;

[0048] P123 0.04 parts;

[0049] 0.6 parts of tetraethylammonium chloride.

[0050] This embodiment also provides a method for preparing the aforementioned highly dispersed nano-high purity magnesium oxide powder. After the surfactant is uniformly dispersed in water to form spherical micelles, alkyl magnesium chloride is added, the surface of the spherical micelles is coated with alkyl, and magnesium ions penetrate into the spherical micelles. Then, under the action of the reaction aid, Mg(OH) x (CO) y (NH2) z -R, spherical Mg(OH) is obtained by drying x (CO) y (NH2) z -R powder, and then calcined to obtain highly dispersed nano high-purity magnesium oxide powder.

[0051] Wherein, the spherical Mg(OH) x (CO) y (NH2) z In -R powder, x=1, y=1, z=1, and R is C2H5.

[0052] The method for preparing highly dispersed nano high-purity magnesium oxide powder comprises the following steps:

[0053] Step S001, adding a surfactant to water at a temperature of 60° C., further adding alkyl magnesium chloride under high-speed stirring conditions of 1200 r / min, mixing and stirring for 0.5 h, standing and cooling for 2 h, to obtain a transparent low-viscosity slurry with a viscosity of 500 Pa·s.

[0054] Step S002, adding a reaction aid to the transparent low-viscosity slurry, stirring at 1200 r / min and 60° C., mixing and stirring for 0.5 h or more to obtain a white uniform solution, and letting it stand for 1 h or more to obtain a white precipitate slurry.

[0055] Step S003, after centrifuging the white precipitate slurry, washing the solid matter three times with water of equal mass to obtain a white precipitate.

[0056] Step S004, in a normal pressure environment, the baking temperature is controlled to be 85° C., and the white precipitate is baked for 5 hours to obtain a white single powder.

[0057] Step S005, calcining the white single powder, controlling the calcination heating rate to 2°C / min, heating to 1250°C, and calcining for 3 hours to obtain highly dispersed nano high-purity magnesium oxide powder.

[0058] The method for preparing highly dispersed nanometer high-purity magnesium oxide powder of the present embodiment has a narrow powder particle size distribution, good preparation process stability, simple process, low production energy consumption and low production cost; nanometer magnesium oxide powder in a highly crystalline and highly dispersed state can be obtained in one step, there is no powder agglomeration problem in the preparation process, and there is no need to use grinding equipment in combination with solvents and dispersing aids to carry out high dispersion treatment of nanometer powders after calcination, which further greatly reduces production costs and energy consumption.

[0059] Example 2

[0060] This embodiment provides a highly dispersed nano-high purity magnesium oxide powder, and the specific specifications are shown in Table 2:

[0061] Table 2 Specific specifications of highly dispersed nano high purity magnesium oxide powder of Example 2

[0062]

[0063] The highly dispersed nanometer high-purity magnesium oxide powder is prepared from the following raw materials: alkyl magnesium chloride, reaction aid, surfactant and water.

[0064] The alkyl magnesium chloride is a combination of methyl magnesium chloride and cyclohexyl magnesium chloride; the mass ratio of the methyl magnesium chloride to the cyclohexyl magnesium chloride is 1:1.

[0065] The reaction aid is tetramethylammonium bromide.

[0066] The surfactant is polyoxyethylene-polyoxypropylene ether block copolymer F127.

[0067] Wherein, the mass ratio of alkyl magnesium chloride to water is 50:50.

[0068] The amount of surfactant used is 0.15% of the mass of alkyl magnesium chloride;

[0069] The dosage of the reaction aid is 2% of the mass of the alkyl magnesium chloride.

[0070] Specifically, the specific weight portions of the above raw materials are as follows:

[0071] 25 parts of methylmagnesium chloride;

[0072] 25 parts of cyclohexylmagnesium chloride;

[0073] 50 parts water;

[0074] F127 0.075 parts;

[0075] 1 part of tetramethylammonium bromide.

[0076] This embodiment also provides a method for preparing the aforementioned highly dispersed nano-high purity magnesium oxide powder. After the surfactant is uniformly dispersed in water to form spherical micelles, alkyl magnesium chloride is added, the surface of the spherical micelles is coated with alkyl, and magnesium ions penetrate into the spherical micelles. Then, under the action of the reaction aid, Mg(OH) x (CO) y (NH2) z -R, spherical Mg(OH) is obtained by drying x (CO) y (NH2) z -R powder, and then calcined to obtain highly dispersed nano high-purity magnesium oxide powder; at the same time, in this process, cyclohexyl magnesium chloride did not form an alkyl group, which serves to accelerate the penetration of magnesium ions and the subsequent chemical reaction with the reaction aid.

[0077] Wherein, the spherical Mg(OH) x (CO) y (NH2) z In -R powder, x=1, y=1, z=2, and R is CH3.

[0078] The method for preparing highly dispersed nano high-purity magnesium oxide powder comprises the following steps:

[0079] Step S001, adding a surfactant to water at a temperature of 70°C, further adding alkyl magnesium chloride under high-speed stirring conditions of 1150 r / min, mixing and stirring for 0.5 h, standing and cooling for 2 h, to obtain a transparent low-viscosity slurry with a viscosity of 500 Pa·s.

[0080] Step S002, adding a reaction aid to the transparent low-viscosity slurry, stirring at 1150 r / min and 70° C. for 1 h to obtain a white uniform solution, and letting it stand for 1.5 h to obtain a white precipitate slurry.

[0081] Step S003, after centrifuging the white precipitate slurry, washing the solid matter three times with water of equal mass to obtain a white precipitate.

[0082] Step S004, in a normal pressure environment, the baking temperature is controlled to be 75° C., and the white precipitate is baked for 6 hours to obtain a white single powder.

[0083] Step S005, calcining the white single powder, controlling the calcination heating rate to 2°C / min, heating to 1100°C, and calcining for 3 hours to obtain highly dispersed nano high-purity magnesium oxide powder.

[0084] The method for preparing highly dispersed nanometer high-purity magnesium oxide powder of the present embodiment has a narrow powder particle size distribution, good preparation process stability, simple process, low production energy consumption and low production cost; nanometer magnesium oxide powder in a highly crystalline and highly dispersed state can be obtained in one step, there is no powder agglomeration problem in the preparation process, and there is no need to use grinding equipment in combination with solvents and dispersing aids to carry out high dispersion treatment of nanometer powders after calcination, which further greatly reduces production costs and energy consumption.

[0085] Example 3

[0086] This embodiment provides a highly dispersed nano high-purity magnesium oxide powder, and the specific specifications are shown in Table 3:

[0087] Table 3 Specific specifications of highly dispersed nano high purity magnesium oxide powder of Example 3

[0088]

[0089] The highly dispersed nanometer high-purity magnesium oxide powder is prepared from the following raw materials: alkyl magnesium chloride, reaction aid, surfactant and water.

[0090] The alkyl magnesium chloride is a combination of methyl magnesium chloride and ethyl magnesium chloride; the mass ratio of the methyl magnesium chloride to the ethyl magnesium chloride is 1:1.

[0091] The reaction aid is triethylmethylammonium chloride.

[0092] The surfactant is octadecyltrimethylammonium bromide.

[0093] Wherein, the mass ratio of alkyl magnesium chloride to water is 35:65.

[0094] The amount of surfactant used is 0.1% of the mass of alkyl magnesium chloride;

[0095] The dosage of the reaction aid is 3% of the mass of the alkyl magnesium chloride.

[0096] Specifically, the specific weight portions of the above raw materials are as follows:

[0097] 17.5 parts of methylmagnesium chloride;

[0098] 17.5 parts of ethyl magnesium chloride;

[0099] 65 parts of water;

[0100] 0.035 parts of octadecyltrimethylammonium bromide;

[0101] 1.05 parts of triethylmethylammonium chloride.

[0102] This embodiment also provides a method for preparing the aforementioned highly dispersed nano-high purity magnesium oxide powder. After the surfactant is uniformly dispersed in water to form spherical micelles, alkyl magnesium chloride is added, the surface of the spherical micelles is coated with alkyl, and magnesium ions penetrate into the spherical micelles. Then, under the action of the reaction aid, Mg(OH) x (CO) y (NH2) z -R, spherical Mg(OH) is obtained by drying x (CO) y (NH2) z -R powder, and then calcined to obtain highly dispersed nano high-purity magnesium oxide powder. At the same time, in this process, the ethyl group is enriched inwardly in the spherical micelles, and the methyl group is enriched outwardly in the spherical micelles. The presence of the ethyl group does not show its surface functionality in this embodiment.

[0103] Wherein, the spherical Mg(OH) x (CO) y (NH2) z In -R powder, x=1, y=1, z=2, and R is CH3.

[0104] The method for preparing highly dispersed nano high-purity magnesium oxide powder comprises the following steps:

[0105] Step S001, adding a surfactant to water at a temperature of 80° C., further adding alkyl magnesium chloride under high-speed stirring at 1350 r / min, mixing and stirring for 1 hour, standing and cooling for 2 hours, to obtain a transparent low-viscosity slurry with a viscosity of 600 Pa·s.

[0106] Step S002, adding a reaction aid to the transparent low-viscosity slurry, stirring at 1350 r / min and 80° C. for 2 h to obtain a white uniform solution, and letting it stand for 1 h to obtain a white precipitate slurry.

[0107] Step S003, after centrifuging the white precipitate slurry, washing the solid matter three times with water of equal mass to obtain a white precipitate.

[0108] Step S004, in a normal pressure environment, the baking temperature is controlled to be 80° C., and the white precipitate is baked for 5 hours to obtain a white single powder.

[0109] Step S005, calcining the white single powder, controlling the calcination heating rate to 2.2°C / min, heating to 960°C, and calcining for 3 hours to obtain highly dispersed nano high-purity magnesium oxide powder.

[0110] The method for preparing highly dispersed nanometer high-purity magnesium oxide powder of the present embodiment has a narrow powder particle size distribution, good preparation process stability, simple process, low production energy consumption and low production cost; nanometer magnesium oxide powder in a highly crystalline and highly dispersed state can be obtained in one step, there is no powder agglomeration problem in the preparation process, and there is no need to use grinding equipment in combination with solvents and dispersing aids to carry out high dispersion treatment of nanometer powders after calcination, which further greatly reduces production costs and energy consumption.

[0111] Comparative Example 1

[0112] Comparative Example 1 adopts the technical solution of Example 1, except that ammonium acetate is used instead of tetraethylammonium chloride, a reaction aid, and the amount of ammonium acetate is kept the same as that of tetraethylammonium chloride.

[0113] In the preparation process of magnesium oxide powder in comparative example 1, Mg(OH)2•3H2O is formed under the action of reaction aid ammonium acetate, and spherical Mg(OH)2•3H2O powder is obtained by drying, and then magnesium oxide powder is obtained by calcination. In this process, the ethyl group of ethyl magnesium chloride will be enriched inward along with magnesium ions, and alkylated powder cannot be formed.

[0114] The specific specifications of the magnesium oxide powder of Comparative Example 1 are shown in Table 4:

[0115] Table 4 Specific specifications of magnesium oxide powder of Comparative Example 1

[0116]

[0117] It can be seen that during the preparation process of the magnesium oxide powder of Comparative Example 1, there is agglomeration of the powder, and hard agglomerates are generated during the sintering process. The main reason is that the powder prepared in Comparative Example 1 does not carry relevant groups. Although the crystal grains of the powder can reach the nanoscale (35nm), the agglomeration is serious during the preparation process, and chemical forces are generated between the grains during the subsequent sintering process, resulting in a large particle size of the magnesium oxide powder finally obtained.

[0118] In summary, the preparation method of highly dispersed nano high-purity magnesium oxide powder of the present invention comprises the following steps: using alkyl magnesium chloride, a reaction aid, and a surfactant, wherein the surfactant is uniformly dispersed in water to form spherical micelles, and then alkyl magnesium chloride is added, and the surface of the spherical micelles is coated with alkyl groups, and magnesium ions penetrate into the spherical micelles, and then, under the action of the reaction aid, Mg(OH) is formed. x (CO) y (NH2) z -R, spherical Mg(OH) is obtained by drying x (CO) y (NH2) z-R powder, and then calcining to obtain highly dispersed nano high-purity magnesium oxide powder; the prepared nano high-purity magnesium oxide powder has a narrow powder particle size distribution, good preparation process stability, simple process, low production energy consumption, and low production cost; it can achieve the integrated preparation of high-crystallization, high-dispersion, and high-purity nano magnesium oxide powder.

[0119] Unless otherwise specified, all percentages used in the present invention are by mass.

[0120] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing highly dispersed nano high-purity magnesium oxide powder, characterized in that: The following raw materials are used for preparation: alkyl magnesium chloride, reaction aid, surfactant and water; The alkyl magnesium chloride is at least one of the following: methyl magnesium chloride, ethyl magnesium chloride, cyclohexyl magnesium chloride; The reaction aid is at least one of the following: tetraethylammonium chloride, tetramethylammonium bromide, triethylmethylammonium chloride; The surfactant is at least one of the following: polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, polyoxyethylene-polyoxypropylene ether block copolymer, octadecyl trimethyl ammonium bromide; The method for preparing highly dispersed nano high-purity magnesium oxide powder comprises the following steps: Step S001, adding a surfactant to water at a temperature of 60-80° C., adding alkyl magnesium chloride under high-speed stirring conditions of 1000 r / min or more, mixing and stirring evenly, and then standing and cooling to obtain a transparent low-viscosity slurry; Step S002, adding a reaction aid to the transparent low-viscosity slurry, mixing and stirring at a high-speed stirring condition of 1000 r / min or more and at a temperature of 60-80° C. to obtain a white uniform solution, and standing for 1 hour or more to obtain a white precipitate slurry; Step S003, after centrifuging the white precipitate slurry, the solid matter is washed with water to obtain a white precipitate; Step S004, baking the white precipitate in a normal pressure environment to obtain a white single powder; Step S005, calcining the white single powder to obtain highly dispersed nano high-purity magnesium oxide powder.

2. The method for preparing highly dispersed nano high-purity magnesium oxide powder according to claim 1, characterized in that: The mass ratio of the alkyl magnesium chloride to water is 35-55:45-65.

3. The method for preparing highly dispersed nano high-purity magnesium oxide powder according to claim 1, characterized in that: The amount of the surfactant is 0.01-0.15% of the mass of the alkyl magnesium chloride; The dosage of the reaction aid is 0.5-3% of the mass of the alkyl magnesium chloride.

4. The method for preparing highly dispersed nano high-purity magnesium oxide powder according to claim 1, characterized in that: In the step S001, the viscosity of the transparent low-viscosity slurry is 400-500 Pa·s.

5. The method for preparing highly dispersed nano high-purity magnesium oxide powder according to claim 1, characterized in that: In step S004, the baking temperature is 75-95° C., and the baking time is 5 hours or more.

6. The method for preparing highly dispersed nano high-purity magnesium oxide powder according to claim 1, characterized in that: In the step S005, the calcination temperature is increased at a rate of 2-2.5°C / min, the temperature is increased to 900-1300°C, and the temperature is maintained for calcination for 3 hours.

7. A highly dispersed nano high-purity magnesium oxide powder, characterized in that: The highly dispersed nano-high purity magnesium oxide powder is prepared by the preparation method according to any one of claims 1 to 6; the particle size d50 of the highly dispersed nano-high purity magnesium oxide powder is 20-35 nm, the magnesium oxide content is ≥99.9wt%, the crystallinity is >99%, and the pH is ≤10.

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