Method for regulating and controlling synthesis of ultrafine powder under reticular framework

Abstract

The invention belongs to the technical field of superfine powder processing and manufacturing, and particularly relates to a method for regulating and controlling synthesis of superfine powder under a net-shaped framework. The method comprises the following steps: dissolving a reticular framework molecule polyethylene glycol (PEG) in an aqueous solution to form a micro-reactor, adsorbing with the surface of a generated carbonate crystal by utilizing the matching of the spatial spacing of an alcohol-oxygen bond and the spatial spacing of metal ions exposed on the surface of the crystal, generating steric hindrance and controlling the growth speed of each crystal face; and the granularity and morphology of the powder are further controlled. The method disclosed by the invention is simple and stable, the production cost is low, industrial production is easily realized in continuous precipitation of rare earth enterprises at present, the prepared oxide is controllable in morphology, small in particle size and uniform in dispersion, and the obtained ultrafine powder material has more plastic physical and chemical properties and has a wide market prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrafine powder processing and manufacturing, and specifically relates to a method for regulating and synthesizing ultrafine powder under a mesh frame. Background Art

[0002] With the rapid development of science and technology in recent years, ultrafine powder technology has shown wide application potential in many high-tech fields due to its unique physical and chemical properties, and has become a frontier field of scientific research today. In particular, rare earth elements have shown incomparable application value in many high-tech fields, such as precision ceramics, biomedicine, optoelectronic sensors, polishing and catalysis, due to their unique electronic appearance and structure, which determines their unique physical and chemical properties.

[0003] At present, there are many methods for preparing ultrafine powders, and the appropriate method should be selected according to specific needs and material properties. Liquid phase precipitation is the main method for preparing ultrafine powders in industry, which has the advantages of mild reaction conditions, simple large-scale application, and wide application range. However, most of the small-particle powders produced in industry are made uniformly distributed by methods such as gas crushing and ball milling, which destroys the original morphology of the powder, not only affecting the performance stability of the ultrafine powder, but also increasing the difficulty of subsequent processing and application limitations. Although polyethylene glycol is added in the public documents, it mostly plays a role in dispersion and anti-agglomeration.

[0004] By studying chemical interaction systems, we can deeply explore the subtle differences and characteristics of various materials, and by regulating and controlling at the atomic scale to customize "demand-oriented" materials, it is the key to opening up a new field of material research. At this stage, the problem of ultrafine powder size uniformity and sintering agglomeration in the preparation process is solved to ensure that the prepared powder has excellent performance and application value. Seeking a method for preparing ultrafine powders with controllable particle size can help the rapid development of related industries, meet industry needs, and promote the sustainable and healthy development of related industries. Summary of the invention

[0005] In view of this, in order to solve the problems of large particle size, uneven distribution, and agglomeration between particles of powders prepared by traditional production processes, the present invention provides a method for preparing ultrafine powders, which adopts a liquid phase precipitation method and controls particle growth by adding a mesh framework PEG, thereby effectively solving the problems of sintering agglomeration and particle size uniformity.

[0006] It should be noted that solving the problem of uneven particle size distribution and agglomeration between particles are two important ways to prepare the prior art problems of ultrafine powder in industry. As is known to all, polyethylene glycol (PEG) has two hydrophilic groups of ether group and hydroxyl group but no hydrophobic group due to its unique molecular formula structure, and can be well fused with aqueous solution, and with the change of polymerization degree and addition amount, the carbon chain undergoes conformational changes such as bending and twisting, forming a microreactor of spatial reticular structure, using the spatial spacing of alcohol oxygen bonds to match the spatial spacing of metal ions exposed on the crystal surface, adsorbing on the surface of generated carbonate crystals, generating steric hindrance, controlling the growth rate of each crystal face, and after burning carbonate, the control function of the reticular framework molecular microreactor ends, and the oxide obtained inherits the morphological characteristics of the precursor, thereby controlling the particle size of the final oxide powder. The present invention is simple in process, strong in controllability, and the generated filtrate is recycled, reducing the input of polyethylene glycol (PEG), reducing production costs, and solving the problem of wastewater recovery, so the industrialization transformation of the later achievements has obvious advantages.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A method for preparing ultrafine powder by regulating synthesis under a mesh framework, specifically comprising the following steps:

[0009] (1) preparing a reaction solution of a certain concentration and dissolving the mesh framework PEG therein, then dropping a precipitant solution therein, heating and stirring for a certain period of time, and obtaining a carbonate precipitate;

[0010] (2) Separating the carbonate filter cake through water washing, suction filtration, aging, alcohol washing, drying and other processes;

[0011] (3) Ultrafine powder can be obtained by calcining in a box-type resistance furnace.

[0012] Preferably, the reaction liquid is a soluble rare earth salt solution such as cerium nitrate, cerium chloride, lanthanum nitrate, yttrium nitrate, zirconium nitrate, etc., and the ion concentration in the reaction liquid is 0.1-1 mol / L; the addition amount of the reticular framework PEG is 1-100% of the mass of the prepared oxide powder, preferably 20-80%.

[0013] Preferably, the precipitant solution is a soluble salt containing carbonate ions, specifically ammonium bicarbonate, ammonium carbonate, sodium carbonate, sodium bicarbonate, etc., preferably ammonium bicarbonate commonly used in industrial production; the concentration of the precipitant solution is 0.1-1 mol / L, and the added amount is 1-1.8 times the mass of the prepared oxide powder.

[0014] Furthermore, in step (1), the stirring rate is 200-800 r / min, the precipitation agent drop rate is 5-50 ml / min, and the reaction temperature is 25-80°C.

[0015] Preferably, in step (2), the aging time is 1 to 24 hours, and the selected aging medium is the raw material used in the production process of ultrafine powder so as not to introduce new impurities, such as ammonia water, ammonium bicarbonate, polyethylene glycol, ethanol, pure water, etc.

[0016] Preferably, in step (2), the washing times are 1 to 5 times, and the drying temperature is 30 to 100°C.

[0017] Furthermore, in step (3), the calcination temperature of the box-type resistance furnace is 500-1600° C., the heating rate is 100-500° C. / h, and the insulation time is 1-5h.

[0018] It should be noted that the ultrafine powder prepared by the above method has good particle size uniformity and uniformity. ≤2, particle size (D MAX ) is less than 2μm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The ultrafine powder produced by the method disclosed in the present invention has controllable morphology, small particle size, good dispersibility, and the addition of the PEG network framework can regulate the growth process of the particles, thereby ensuring the uniformity of the particle size and solving the agglomeration problem of the product.

[0021] (2) The preparation method disclosed in the present invention is relatively accurate and can avoid the introduction of impurities, thereby improving the purity of the prepared powder.

[0022] (3) The preparation method disclosed in the present invention has a short process and low cost, and eliminates the industrial process of ball milling or air flow crushing, and can directly obtain products that meet customer needs.

[0023] (4) The preparation method disclosed in the present invention is simple, the reaction process is easy to control, the requirements for equipment are low, the filtrate is refluxed, the process is green and environmentally friendly, and it is easy to realize industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 As a comparative experiment, SEM images of cerium carbonate (a), cerium dioxide (b) and particle size image of cerium oxide (c) prepared in Example 1 without a mesh frame are shown;

[0026] Figure 2 The SEM images of cerium carbonate (a), cerium dioxide (b) and particle size image of cerium oxide (c) prepared in Example 1 of the present invention are shown;

[0027] Figure 3 The SEM image (a) and particle size image (b) of cerium dioxide prepared in Example 2 of the present invention;

[0028] Figure 4 The SEM image (a) and particle size image (b) of cerium dioxide prepared in Example 3 of the present invention;

[0029] Figure 5 The SEM image (a) and particle size image (b) of cerium dioxide prepared in Example 4 of the present invention;

[0030] Figure 6 The SEM image (a) and particle size image (b) of cerium dioxide prepared in Example 5 of the present invention;

[0031] Figure 7 This is a laser particle size analysis diagram of lanthanum oxide prepared in Example 6 of the present invention. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0033] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0034] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0035] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0036] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0037] The invention discloses a method for regulating and synthesizing ultrafine powder under a reticular frame.

[0038] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0039] Example 1

[0040] (1) Take 46.5 ml of 1.25 mol / L cerium nitrate solution and dissolve it in 70 ml of pure water to prepare the solution. 3+ The concentration is 0.5 mol / L, add 8 g of polyethylene glycol (PEG1000) to the cerium salt solution and mix well;

[0041] (2) Weigh 15 g of ammonium bicarbonate and dissolve it in 120 ml of pure water to prepare a precipitant solution;

[0042] (3) adding the precipitant to the cerium salt solution at a rate of 15 ml / min, the reaction temperature is 60° C., the stirring rate is 500 r / min, after the reaction is completed, the mixed solution is filtered and washed with water, placed in a 90° C. water bath pot for aging with pure water for 24 h, washed with alcohol, filtered and dried at a drying temperature of 60° C., and an ultrafine cerium carbonate precursor with controllable morphology and uniform size is obtained;

[0043] (4) The ultrafine cerium carbonate precursor is calcined at a high temperature of 1000°C and a holding time of 2 hours to obtain a cerium oxide powder with a morphology inherited from the precursor and a uniformly dispersed particle size. 90 =0.408μm, R=0.5.

[0044] Example 2

[0045] (1) Take 55 ml of 1.05 mol / L cerium chloride solution and dissolve it in 61.5 ml of pure water to prepare the solution. 3+ The concentration is 0.5 mol / L; 8 g of polyethylene glycol (PEG1000) is added to the cerium salt solution and mixed evenly;

[0046] (2) Weigh 15 g of ammonium bicarbonate and dissolve it in 120 ml of pure water to prepare a precipitant solution;

[0047] (3) adding the precipitant to the cerium salt solution at a rate of 15 ml / min, the reaction temperature is 60° C., the stirring rate is 500 r / min, after the reaction is completed, the mixed solution is filtered and washed with water, placed in a 90° C. water bath pot for aging with pure water for 24 h, washed with alcohol, filtered and dried at a drying temperature of 60° C., to obtain an ultrafine cerium carbonate precursor;

[0048] (4) The ultrafine cerium carbonate salt precursor is calcined at a high temperature of 1000° C. and a holding time of 2 h to obtain ultrafine cerium oxide powder.

[0049] Because Ce 3+ The stability of the Ce-O bond generated by the interaction with the alcohol oxygen bond in PEG is quite different, and the chlorination system is weaker than the nitric acid system. Therefore, the adsorption of the mesh framework molecules on the crystal surface of cerium carbonate is weakened. 90 =1.529μm.

[0050] Example 3

[0051] (1) Take 46.5 ml of 1.25 mol / L cerium nitrate solution and dissolve it in 70 ml of pure water to prepare the solution. 3+ The concentration is 0.5 mol / L; 6 g of polyethylene glycol (PEG1000) is added to the cerium salt solution and mixed evenly;

[0052] (2) Weigh 15 g of ammonium bicarbonate and dissolve it in 120 ml of pure water to prepare a precipitant solution;

[0053] (3) adding the precipitant to the cerium salt solution at a rate of 15 ml / min, the reaction temperature is 60° C., the stirring rate is 500 r / min, after the reaction is completed, the mixed solution is filtered and washed with water, placed in a 90° C. water bath pot for aging with pure water for 24 h, washed with alcohol, filtered and dried at a drying temperature of 60° C., to obtain an ultrafine cerium carbonate precursor;

[0054] (4) The ultrafine cerium carbonate precursor is calcined at a high temperature of 1000° C. and a holding time of 2 h to obtain ultrafine cerium oxide powder.

[0055] Example 4

[0056] (1) Take 46.5 ml of 1.25 mol / L cerium nitrate solution and dissolve it in 70 ml of pure water to prepare the solution. 3+ The concentration is 0.5 mol / L; 6 g of polyethylene glycol (PEG10000) is added to the cerium salt solution and mixed evenly;

[0057] (2) Weigh 18 g of ammonium bicarbonate and dissolve it in 120 ml of pure water to prepare a precipitant solution;

[0058] (3) adding the precipitant to the cerium salt solution at a rate of 15 ml / min, the reaction temperature is 60° C., the stirring rate is 500 r / min, after the reaction is completed, the mixed solution is filtered and washed with water, placed in a 90° C. water bath pot for aging with pure water for 24 h, washed with alcohol, filtered and dried at a drying temperature of 40° C., to obtain an ultrafine cerium carbonate precursor;

[0059] (4) The ultrafine cerium carbonate precursor is calcined at a high temperature of 1000° C. and a holding time of 2 h to obtain ultrafine cerium oxide powder.

[0060] Example 5

[0061] (1) Take 46.5 ml of 1.25 mol / L cerium nitrate solution and dissolve it in 70 ml of pure water to prepare the solution. 3+ The concentration is 0.5 mol / L; 8 g of polyethylene glycol (PEG1000) is added to the cerium salt solution and mixed evenly;

[0062] (2) Weigh 18 g of ammonium bicarbonate and dissolve it in 120 ml of pure water to prepare a precipitant solution;

[0063] (3) adding the precipitant to the cerium salt solution at a rate of 15 ml / min, the reaction temperature is 60° C., the stirring rate is 500 r / min, and after the reaction is completed, the mixed solution is filtered and washed with water, placed in a 90° C. water bath pot for aging with ammonia water for 24 h, washed with alcohol, filtered and dried to obtain an ultrafine cerium carbonate salt precursor;

[0064] (4) The ultrafine cerium carbonate salt precursor is calcined at a high temperature of 500° C. and a holding time of 2 h to obtain ultrafine cerium dioxide powder.

[0065] Example 6

[0066] (1) Take 38 ml of 2.16 mol / L lanthanum nitrate solution and dissolve it in 80 ml of pure water to prepare the solution. 3+ The concentration is 0.5 mol / L; 8 g of polyethylene glycol (PEG1000) is added to the reaction solution and mixed evenly;

[0067] (2) Weigh 15 g of ammonium bicarbonate and dissolve it in 120 ml of pure water to prepare a precipitant solution;

[0068] (3) adding the precipitant to the reaction solution at a rate of 15 ml / min, the reaction temperature is 60° C., the stirring rate is 400 r / min, and after the reaction is completed, the mixed solution is filtered and washed with water, placed in a 90° C. water bath for aging with pure water for 24 h, washed with alcohol, filtered, and then dried at a drying temperature of 45° C. to obtain an ultrafine lanthanum carbonate precursor;

[0069] (4) The ultrafine lanthanum carbonate precursor is calcined at a high temperature of 1000° C. and a holding time of 3 h to obtain ultrafine lanthanum oxide powder.

[0070] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the following comparative examples are used to further illustrate the technical features disclosed in the present invention, but they should not be construed as limiting the present invention. Other improvements made by those skilled in the art based on the above invention content without inventive work are also considered to fall within the scope of protection of the present invention.

[0071] Comparative Example 1

[0072] No network framework cerium particles were added, as a comparative experiment:

[0073] (1) Take 46.5 ml of 1.25 mol / L cerium nitrate solution and dissolve it in 70 ml of pure water to prepare the solution. 3+ The concentration is 0.5mol / L, mix well;

[0074] (2) Weigh 15 g of ammonium bicarbonate and dissolve it in 120 ml of pure water to prepare a precipitant solution;

[0075] (3) adding the precipitant to the cerium salt solution at a rate of 15 ml / min, the reaction temperature is 60° C., the stirring rate is 500 r / min, and after the reaction is completed, the mixed solution is filtered and washed with water, placed in a 90° C. water bath pot for aging with pure water for 24 h, washed with alcohol, filtered and dried at a drying temperature of 60° C. to obtain an irregular cerium carbonate precursor;

[0076] (4) The ultrafine cerium carbonate precursor is calcined at a high temperature of 1000°C and a holding time of 2 hours to obtain cerium oxide powder with flake particles of different sizes agglomerated together. 90 =46.94μm.

[0077] By comparison, it was found that without adding mesh framework PEG, Ce 3+ There is no fixed nucleation site. After the precipitant carbonate is added, it reacts with Ce 3+ The reaction space is uncontrolled, resulting in irregular product morphology and a dramatic increase in particle size. However, the addition of PEG to the mesh framework forms a pre-set, highly ordered reaction system, with the alcohol oxygen bond and Ce 3+It constitutes nucleation sites and controls the growth rate of each crystal face of the precursor carbonate crystal, so that the morphology and particle size of the product can be controlled. By adjusting the amount of the mesh framework PEG and changing the reaction parameters according to the feed-liquid system, ultrafine powders can be obtained.

[0078] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for regulating and synthesizing ultrafine powder under a mesh framework, characterized in that: The method specifically comprises the following steps: (1) preparing a reaction liquid and dissolving the mesh framework molecule PEG therein, then dripping a precipitant solution, heating and stirring to obtain a carbonate precipitate; (2) washing the carbonate precipitate with water, aging, alcohol washing, and drying to separate the carbonate filter cake; (3) The carbonate filter cake is calcined to obtain ultrafine oxide powder.

2. The method according to claim 1, characterized in that The reaction liquid is a rare earth soluble salt solution, and the ion concentration in the reaction liquid is 0.1-1 mol / L.

3. The method according to claim 1, characterized in that The added amount of the mesh framework molecule PEG is 1 to 100% of the mass of the prepared oxide powder.

4. The method according to claim 1, characterized in that The precipitant solution is a salt solution containing carbonate ions, the concentration of the precipitant solution is 0.1-1 mol / L, and the added amount is 1-1.8 times the mass of the prepared oxide powder.

5. The method according to any one of claims 1 to 4, characterized in that: In step (1), the stirring rate is 200-800 r / min, the precipitation agent drop rate is 5-50 ml / min, and the reaction temperature is 25-80°C.

6. The method according to claim 1, characterized in that In step (2), the aging time is 1 to 24 hours, the number of water washings is 1 to 5 times, and the drying temperature is 30 to 100°C.

7. The method according to claim 1, characterized in that In step (3), the calcination temperature is 500-1600° C., the heating rate is 100-500° C. / h, and the insulation time is 1-5h.

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