Method for preparing high-purity nano magnesium oxide by taking industrial magnesium oxide as raw material

Abstract

The invention relates to the field of novel chemical materials, in particular to a method for preparing high-purity nano magnesium oxide by taking industrial magnesium oxide as a raw material, which comprises the following steps: carrying out acidolysis on the industrial magnesium oxide as the raw material and sulfuric acid to generate a magnesium sulfate solution, adding a small amount of high-purity magnesium oxide, filtering to obtain a refined magnesium sulfate solution, adding a surfactant into the solution, and stirring to obtain the high-purity nano magnesium oxide. Dropwise adding an oxalic acid solution to obtain a modified magnesium oxalate intermediate; and grinding the magnesium oxalate intermediate, and heating and decomposing in a roasting furnace to obtain the high-purity nano magnesium oxide product. The industrial magnesium oxide is used as the raw material, the refining impurity removal and intermediate surface treatment technology is adopted, the high-purity nanometer magnesium oxide is controllably prepared, the additional value of the industrial magnesium oxide is improved, the high-purity nanometer magnesium oxide with the average particle size being 30 nm and the purity being 99.9% is obtained, and the high-purity nanometer magnesium oxide can be widely applied to the fields of high-thermal-conductivity substrate materials, lithium battery positive electrode materials and catalysts. The large-scale production of the high-purity nano magnesium oxide is realized, and the technology has great industrial value and practical significance.

Description

Technical Field

[0001] The invention relates to the field of new chemical materials, and in particular to a method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as a raw material. Background Art

[0002] As a new type of inorganic functional material with great potential, high-purity nano-magnesium oxide has shown broad application prospects in many important fields in recent years, attracting widespread attention from the scientific research and industry communities.

[0003] In the field of lithium battery electrode materials, the unique properties of high-purity nano magnesium oxide can significantly improve the performance of lithium batteries. It can be used as an electrode additive to effectively improve the structural stability and electrochemical properties of electrode materials, improve the battery's charge and discharge efficiency, cycle life and safety, and thus provide strong support for the widespread application of lithium batteries in electric vehicles and portable electronic devices. In terms of high-heat-resistant substrate materials, high-purity nano magnesium oxide has become an ideal material for manufacturing high-heat-resistant substrates due to its excellent high-temperature resistance and good insulation. This substrate can maintain stable performance under high-temperature conditions, provide reliable support and protection for electronic components, and is widely used in aerospace and high-end electronic equipment that require extremely high heat resistance. In the field of catalysts, high-purity nano magnesium oxide has a large specific surface area and abundant active sites, which can significantly improve the activity and selectivity of catalytic reactions, and plays an important role in catalytic reactions in the fields of petrochemicals and environmental protection. In addition, high-purity nano magnesium oxide also has good antibacterial properties and can be used to prepare antibacterial materials. It has potential application value in the fields of food packaging, medical and health care, and daily necessities.

[0004] At present, there are many methods for preparing nano magnesium oxide, mainly including sol-gel method, hydrothermal uniform precipitation method and direct precipitation method. Most of these preparation methods use magnesium sulfate and magnesium chloride as raw materials, and first obtain intermediates such as magnesium hydroxide and magnesium carbonate (or basic magnesium carbonate) through specific chemical reactions. Subsequently, these intermediates are calcined and decomposed to obtain nano magnesium oxide. However, there is a more prominent problem in these existing preparation methods, that is, the purity of the prepared nano magnesium oxide is generally not high, mostly less than 99.9%. The low purity will greatly limit the application of nano magnesium oxide in some high-end fields, for example, in the field where lithium battery electrode materials and high heat-resistant substrate materials have extremely high purity requirements, low-purity nano magnesium oxide cannot meet its performance requirements.

[0005] In addition, from the perspective of the use of raw materials, there are relatively few studies and practices on the production of nano-magnesium oxide using industrial magnesium oxide as raw material, and there are almost no cases of producing high-purity nano-magnesium oxide directly using industrial magnesium oxide as raw material. As a bulk industrial raw material with a wide source and relatively low cost, if an effective method for preparing high-purity nano-magnesium oxide using industrial magnesium oxide as raw material can be developed, it can not only solve the problem of low purity in existing preparation methods, but also reduce production costs, improve resource utilization, and have significant economic and social benefits. Therefore, we proposed a method for preparing high-purity nano-magnesium oxide using industrial magnesium oxide as raw material, aiming to explore a new way to prepare high-purity nano-magnesium oxide that is more efficient, more economical and can produce high-purity nano-magnesium oxide. Summary of the invention

[0006] The purpose of the present invention is to solve the problems in the existing background technology. In order to achieve the above invention purpose, the present invention provides the following technical scheme: a method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material, comprising the following steps: step 1, using industrial magnesium oxide as raw material, reacting with sulfuric acid solution to obtain magnesium sulfate solution;

[0007] Step 2, adding a chelating agent to the magnesium sulfate solution to remove impurities, and filtering to obtain a refined magnesium sulfate solution;

[0008] Step 3, mixing the surfactant with the oxalic acid solution, adding the mixture to the refined magnesium sulfate solution, and filtering to obtain a modified magnesium oxalate intermediate;

[0009] Step 4, grinding the magnesium oxalate intermediate until there is no particle feeling;

[0010] Step 5, placing the ground magnesium oxalate powder in a calcining furnace for heating and decomposition to obtain a high-purity nano magnesium oxide product;

[0011] Step 6: Mix the filter residue obtained by refining and removing impurities from the magnesium sulfate solution, the filtrate obtained by filtering magnesium oxalate, and lightly burned magnesium oxide to react with each other to prepare a medium and trace element fertilizer.

[0012] As a preferred technical solution of the present invention, the chelating agent includes phosphoric acid or magnesium oxide.

[0013] As a preferred technical solution of the present invention, the surfactant CTAB, DTAB, or one of them has a concentration of 1% to 2% by mass.

[0014] As a preferred technical solution of the present invention, the preparation of surfactant CTAB includes the following steps: Step 1, weighing 5g of hexadecyltrimethylammonium bromide (CTAB) and 245ml of deionized water;

[0015] Step 2: Add CTAB powder into deionized water and stir evenly to obtain a CTAB surfactant solution with a mass fraction of 2%.

[0016] As a preferred technical solution of the present invention, the surfactant is mixed with an oxalic acid solution, added dropwise to the above-mentioned refined magnesium sulfate solution, and filtered to obtain modified magnesium oxalate crystals.

[0017] As a preferred technical solution of the present invention, the preparation of the magnesium sulfate solution comprises the following steps:

[0018] Step 1, weigh 10g of magnesium oxide powder into a beaker, and add 250mL of deionized water;

[0019] Step 2: Place the beaker in a water bath, set the temperature to 80°C, set the speed to 650 r / min, uniformly add 26 mL of 50% sulfuric acid, react for 30 minutes, filter the solution, and obtain a filtrate magnesium sulfate solution.

[0020] As a preferred technical solution of the present invention, the ground magnesium oxalate is placed in a roasting furnace for heating and decomposition to obtain a high-purity nano magnesium oxide product. The roasting temperature is 500° C. to 700° C. and the roasting time is 1 hour.

[0021] As a preferred technical solution of the present invention, the average particle size of the high-purity nano magnesium oxide is 30 nm and the purity is 99.9%.

[0022] As a preferred technical solution of the present invention, the preparation of modified magnesium oxalate includes the following steps:

[0023] Step 1, weigh 5 g of hexadecyltrimethylammonium bromide (CTAB) into a beaker, add 245 mL of deionized water, and stir evenly with a glass rod until the CTAB is completely dissolved to prepare a 2% concentration of CTAB surfactant solution;

[0024] Step 2, weigh 35g oxalic acid (C 2 H 2 O 4 ·2H 2 O), measure 300mL of deionized water, and mix the two to prepare oxalic acid solution;

[0025] Step 3, add 30 mL of 2% CTAB solution to the pure magnesium sulfate solution, stir at a constant speed for 10 minutes, and then add oxalic acid solution, or mix the two and then add, and stir at a constant speed for 40 minutes; after the reaction is completed, filter the precipitate;

[0026] Step 4: After washing the filter residue with deionized water for three times, place it in a vacuum drying oven for drying. The temperature is set to 100° C. and the drying time is 1 h to obtain a modified magnesium oxalate precursor.

[0027] As a preferred technical solution of the present invention, the industrial magnesium oxide is an industrial magnesium oxide product, and the industrial magnesium oxide product has the characteristics of a bulk product.

[0028] Compared with the prior art, the present invention has the following beneficial effects: In the scheme of the present invention:

[0029] 1. Using bulk industrial magnesium oxide as the raw material for the preparation of high-purity nano magnesium oxide has opened up a new path for the industrial production of high-purity nano magnesium oxide. Industrial magnesium oxide has a wide range of sources and low costs. Compared with the magnesium sulfate and magnesium chloride raw materials used in traditional preparation methods, it can effectively reduce production costs and reduce dependence on specific raw materials. This makes large-scale industrial production of high-purity nano magnesium oxide possible, which helps promote the widespread application of high-purity nano magnesium oxide in various fields and promote the development of related industries.

[0030] 2. The present invention successfully prepared a high-purity nano-magnesium oxide product with an average particle size of 30nm and a purity of up to 99.9%. Nano-scale magnesium oxide with small particle size has a large specific surface area and unique physical and chemical properties, which enables it to show more excellent performance in the fields of lithium battery electrode materials, high heat-resistant substrate materials, catalysts, and antibacterial. The high purity ensures the stability and reliability of the product in high-end application scenarios, can meet the strict requirements of these fields for material purity, and enhance the market competitiveness of the product.

[0031] 3. In the preparation process of the present invention, the filter residue obtained by refining and removing impurities from the magnesium sulfate solution is mixed with the filtrate obtained by filtering magnesium oxalate and lightly burned magnesium oxide to react and prepare medium and trace element fertilizer. The gas released by calcining magnesium oxalate is oxidized and carbonized to produce magnesium carbonate. This measure not only achieves zero emission in the process and avoids the pollution of the environment caused by waste, but also makes full use of the waste in the production process and converts it into products with economic value. Medium and trace element fertilizer plays an important role in the agricultural field. It can supplement a variety of nutrients to the soil, improve soil fertility, and promote the growth and development of crops. This way of recycling resources embodies the concept of green chemistry and sustainable development, and has good environmental and social benefits.

[0032] 4. The high-purity nano magnesium oxide products and medium and trace element fertilizers prepared by the present invention have broad market application prospects. The potential demand for high-purity nano magnesium oxide in multiple high-end fields is huge, and it is expected to bring considerable economic benefits to enterprises. At the same time, the production of medium and trace element fertilizers and magnesium carbonate not only solves the problem of waste disposal, but also opens up new profit growth points for enterprises. In addition, the zero-emission characteristics of the process meet the requirements of national environmental protection policies, help to enhance the social image of enterprises, and have significant social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1A schematic diagram of the method provided by the present invention;

[0034] Figure 2 A schematic diagram of the XRD spectrum of nano-magnesium oxide provided by the present invention;

[0035] Figure 3 This is a scanning electron microscope image of the nano-magnesium oxide provided by the present invention. DETAILED DESCRIPTION

[0036] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0037] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features and technical solutions in the embodiments can be combined with each other without conflict. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0038] Embodiment 1: A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as a raw material, comprising the following steps: Step 1, using industrial magnesium oxide as a raw material, reacting with a sulfuric acid solution to obtain a magnesium sulfate solution;

[0039] Step 2, adding a chelating agent to the magnesium sulfate solution to remove impurities, and filtering to obtain a refined magnesium sulfate solution;

[0040] Step 3, mixing the surfactant with the oxalic acid solution, adding the mixture to the refined magnesium sulfate solution, and filtering to obtain a modified magnesium oxalate intermediate;

[0041] Step 4, grinding the magnesium oxalate intermediate until there is no particle feeling;

[0042] Step 5, placing the ground magnesium oxalate powder in a calcining furnace for heating and decomposition to obtain a high-purity nano magnesium oxide product;

[0043] Step 6: Mix the filter residue obtained by refining and removing impurities from the magnesium sulfate solution, the filtrate obtained by filtering magnesium oxalate, and lightly burned magnesium oxide to react with each other to prepare a medium and trace element fertilizer.

[0044] Chelating agents include phosphoric acid and magnesium oxide.

[0045] The surfactant CTAB, DTAB, or one of them has a concentration of 2% by mass.

[0046] The preparation of surfactant CTAB includes the following steps: Step 1, weighing 5 g of hexadecyltrimethylammonium bromide (CTAB) and 245 ml of deionized water;

[0047] Step 2: Add CTAB powder into deionized water and stir evenly to obtain a CTAB surfactant solution with a mass fraction of 2%.

[0048] The surfactant is mixed with the oxalic acid solution, added dropwise into the above-mentioned refined magnesium sulfate solution, and filtered to obtain modified magnesium oxalate crystals.

[0049] The preparation of magnesium sulfate solution comprises the following steps:

[0050] Step 1, weigh 10g of magnesium oxide powder into a beaker, and add 250mL of deionized water;

[0051] Step 2: Place the beaker in a water bath, set the temperature to 80°C, set the speed to 650 r / min, uniformly add 26 mL of 50% sulfuric acid, react for 30 minutes, filter the solution, and obtain a filtrate magnesium sulfate solution.

[0052] The ground magnesium oxalate is placed in a roasting furnace for heating and decomposition to obtain a high-purity nano magnesium oxide product. The roasting temperature is 500° C. to 700° C. and the roasting time is 1 hour.

[0053] The average particle size of high-purity nano magnesium oxide is 30nm and the purity is 99.9%.

[0054] The preparation of modified magnesium oxalate comprises the following steps:

[0055] Step 1, weigh 5 g of hexadecyltrimethylammonium bromide (CTAB) into a beaker, add 245 mL of deionized water, and stir evenly with a glass rod until the CTAB is completely dissolved to prepare a 2% concentration of CTAB surfactant solution;

[0056] Step 2, weigh 35 g of oxalic acid (C2H2O4·2H2O), measure 300 mL of deionized water, and mix the two to prepare an oxalic acid solution;

[0057] Step 3, add 30 mL of 2% CTAB solution to the pure magnesium sulfate solution, stir at a constant speed for 10 minutes, and then add oxalic acid solution, or mix the two and add dropwise, and stir at a constant speed for 40 minutes; after the reaction is completed, filter the precipitate;

[0058] Step 4: After washing the filter residue with deionized water for three times, place it in a vacuum drying oven for drying. The temperature is set to 100° C. and the drying time is 1 h to obtain a modified magnesium oxalate precursor.

[0059] Industrial magnesium oxide is an industrial magnesium oxide product, which contains bulk product characteristics.

[0060] Embodiment 2: A method for preparing high-purity nano-magnesium oxide using industrial magnesium oxide as raw material, comprising the following steps: first, using industrial magnesium oxide as raw material, reacting with sulfuric acid solution to obtain magnesium sulfate solution, and removing impurities from the magnesium sulfate solution using a chelating agent to obtain a refined magnesium sulfate solution; second, mixing a surfactant with oxalic acid, and adding the mixture dropwise to the refined magnesium sulfate solution to prepare modified magnesium oxalate; third, grinding the modified magnesium oxalate until there is no particle feeling; and fourth, placing the ground magnesium oxalate powder in a roasting furnace for heating and decomposition to obtain a high-purity nano-magnesium oxide product.

[0061] The invention uses industrial magnesium oxide as a raw material to prepare a refined magnesium sulfate solution, which is reacted with oxalic acid to prepare a modified magnesium oxalate intermediate, thereby achieving magnesium oxalate crystal form control; and adopts a heating decomposition technology to obtain high-purity nano magnesium oxide.

[0062] The specific implementation principle of the present invention is:

[0063] (1) Preparation of 2% CTAB: Weigh 5 g of hexadecyltrimethylammonium bromide (CTAB) and 245 ml of deionized water; add CTAB powder into the deionized water and stir evenly to obtain a 2% CTAB surfactant solution.

[0064] (2) Preparation of magnesium sulfate solution: Weigh 10 g of magnesium oxide powder and put it into a beaker, add 250 mL of deionized water, place the beaker in a water bath, set the temperature to 80° C., set the speed to 650 r / min, uniformly add 26 mL of 50% sulfuric acid, react for 30 minutes, filter the solution, and obtain a filtrate magnesium sulfate solution.

[0065] A chelating agent (phosphoric acid or magnesium oxide) is added to the magnesium sulfate solution, and after stirring for a certain period of time, the solution is filtered to obtain a purified magnesium sulfate solution.

[0066] (3) Preparation of modified magnesium oxalate: Weigh 5 g of hexadecyltrimethylammonium bromide (CTAB) into a beaker, add 245 mL of deionized water, and stir evenly with a glass rod until the CTAB is completely dissolved to prepare a 2% concentration of CTAB surfactant solution.

[0067] Weigh 35 g of oxalic acid (C2H2O4·2H2O) and 300 mL of deionized water, and mix the two to prepare an oxalic acid solution.

[0068] 30 mL of 2% CTAB solution was added dropwise to the pure magnesium sulfate solution, and the mixture was stirred at a constant speed for 10 min, and then the oxalic acid solution was added dropwise, or the two were mixed and added dropwise, and the mixture was stirred at a constant speed for 40 min. After the reaction was completed, the precipitate was filtered.

[0069] The filter residue was washed three times with deionized water and then placed in a vacuum drying oven for drying. The temperature was set to 100° C. and the drying time was 1 h to obtain a modified magnesium oxalate precursor.

[0070] (4) Grinding: Grind the modified magnesium oxalate precursor until the modified magnesium oxalate is free of particles.

[0071] (5) Preparation of high-purity nano-magnesium oxide: The ground magnesium oxalate was loaded into a magnetic boat and sealed, and placed in a high-temperature tube furnace. The calcination temperature was set to 625°C, the heating rate was 10°C / min, and the calcination time was 1h. After the calcination was completed, the calcined product was taken out and naturally cooled to room temperature, and then ground again to obtain a uniform nano-magnesium oxide product.

[0072] (6) Medium and trace element fertilizers: The residue from the refined magnesium sulfate solution, the filtrate from the filtered magnesium oxalate, and lightly burned magnesium oxide are reacted according to the standard ingredients for medium and trace element fertilizers to produce medium and trace element fertilizers, thereby ensuring zero emissions in the process.

[0073] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the above specific implementation methods. Therefore, any modification or replacement of the present invention; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the invention are included in the scope of the claims of the present invention.

Claims

1. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material, characterized in that: The following steps are involved: Step 1, using industrial magnesium oxide as a raw material, reacting with sulfuric acid solution to obtain a magnesium sulfate solution; Step 2, adding a chelating agent to the magnesium sulfate solution to remove impurities, and filtering to obtain a refined magnesium sulfate solution; Step 3, mixing the surfactant with the oxalic acid solution, adding the mixture to the refined magnesium sulfate solution, and filtering to obtain a modified magnesium oxalate intermediate; Step 4, grinding the magnesium oxalate intermediate until there is no particle feeling; Step 5, placing the ground magnesium oxalate powder in a calcining furnace for heating and decomposition to obtain a high-purity nano magnesium oxide product; Step 6: Mix the filter residue obtained by refining and removing impurities from the magnesium sulfate solution, the filtrate obtained by filtering magnesium oxalate, and lightly burned magnesium oxide to react with each other to prepare a medium and trace element fertilizer.

2. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 1, characterized in that: The chelating agent includes phosphoric acid or magnesium oxide.

3. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 2, characterized in that: The surfactant is CTAB, DTAB, or one of them, and the concentration mass percentage is 1-2%.

4. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 3, characterized in that: The preparation of surfactant CTAB includes the following steps: Step 1, weigh 5 g of hexadecyltrimethylammonium bromide (CTAB) and 245 ml of deionized water; Step 2: Add CTAB powder into deionized water and stir evenly to obtain a CTAB surfactant solution with a mass fraction of 2%.

5. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 4, characterized in that: The surfactant is mixed with the oxalic acid solution, added dropwise into the refined magnesium sulfate solution, and filtered to obtain modified magnesium oxalate crystals.

6. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 5, characterized in that: The magnesium sulfate solution preparation comprises the following steps: Step 1, weigh 10g of magnesium oxide powder into a beaker, and add 250mL of deionized water; Step 2: Place the beaker in a water bath, set the temperature to 80°C, set the speed to 650 r / min, uniformly add 26 mL of 50% sulfuric acid, react for 30 minutes, filter the solution, and obtain a filtrate magnesium sulfate solution.

7. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 6, characterized in that: The ground magnesium oxalate is placed in a roasting furnace for heating and decomposition to obtain a high-purity nano magnesium oxide product. The roasting temperature is 500° C. to 700° C. and the roasting time is 1 hour.

8. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 7, characterized in that: The average particle size of the high-purity nano magnesium oxide is 30 nm and the purity is 99.9%.

9. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 8, characterized in that: The preparation of modified magnesium oxalate comprises the following steps: Step 1, weigh 5 g of hexadecyltrimethylammonium bromide (CTAB) into a beaker, add 245 mL of deionized water, and stir evenly with a glass rod until the CTAB is completely dissolved to prepare a 2% concentration of CTAB surfactant solution; Step 2, weigh 35 g of oxalic acid (C2H2O4·2H2O), measure 300 mL of deionized water, and mix the two to prepare an oxalic acid solution; Step 3, add 30 mL of 2% CTAB solution to the pure magnesium sulfate solution, stir at a constant speed for 10 minutes, and then add oxalic acid solution, or mix the two and then add, and stir at a constant speed for 40 minutes; after the reaction is completed, filter the precipitate; Step 4: After washing the filter residue with deionized water for three times, place it in a vacuum drying oven for drying. The temperature is set to 100° C. and the drying time is 1 h to obtain a modified magnesium oxalate precursor.

10. A method for preparing high-purity nano magnesium oxide using industrial magnesium oxide as raw material according to claim 9, characterized in that: The industrial magnesium oxide is an industrial magnesium oxide product, and the industrial magnesium oxide product has the characteristics of a bulk product.

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