阅读说明：本技术 一种二氧化铀纳米材料的制备方法 (Preparation method of uranium dioxide nano material ) 是由 赵耀林 左峰 聂少尉 肖松涛 刘协春 江莉莉 于 2020-05-27 设计创作，主要内容包括：本发明公开了一种二氧化铀纳米材料的制备方法,属于纳米材料技术领域。所述的制备方法是将硝酸铀酰溶液与氢氧化钠溶液混合均匀,加入反应釜中水热反应,反应产物冷却到室温后水洗涤至pH为7.5-8.5,烘干研磨,所得粉末置于管式炉中通入氢气还原,即制得二氧化铀纳米材料。利用本发明的二氧化铀纳米材料的制备方法,能够大规模制备形貌可控、团聚较轻、粒径均匀、比表面积较高、催化活性好的UO<Sub>2</Sub>陶瓷纳米粉体。(The invention discloses a preparation method of a uranium dioxide nano material, belonging to the technical field of nano materials. The preparation method comprises the steps of uniformly mixing a uranyl nitrate solution and a sodium hydroxide solution, adding the mixture into a reaction kettle for hydrothermal reaction, cooling a reaction product to room temperature, and then adding the cooled reaction productWashing with water until the pH value is 7.5-8.5, drying and grinding, and introducing hydrogen into the obtained powder in a tubular furnace for reduction to obtain the uranium dioxide nano material. By using the preparation method of the uranium dioxide nano material, the UO with controllable morphology, lighter agglomeration, uniform particle size, higher specific surface area and good catalytic activity can be prepared in a large scale 2 Ceramic nano-powder.)

1. A preparation method of a uranium dioxide nano material is characterized by comprising the following steps: the preparation method comprises the steps of uniformly mixing a uranyl nitrate solution and a sodium hydroxide solution, adding the mixture into a reaction kettle for hydrothermal reaction, cooling a reaction product to room temperature, washing the reaction product with water until the pH value is 7.5-8.5, drying and grinding the reaction product, and placing the obtained powder into a tubular furnace to introduce hydrogen for reduction to obtain the uranium dioxide nano material.

2. The method of claim 1, wherein: the concentration of the uranyl nitrate solution is 0.5-1.0mol/L, the concentration of the sodium hydroxide solution is 5-8mol/L, and the mixing volume ratio of the uranyl nitrate solution to the sodium hydroxide solution is 1:20-1: 10.

3. The method of claim 1, wherein: the reaction kettle is a stainless steel high-temperature high-pressure reaction kettle taking polytetrafluoroethylene as a lining.

4. The method of claim 1, wherein: the temperature of the hydrothermal reaction is 80-100 ℃, the pressure is 0.6-0.8MPa, and the time is 18-48 hours.

5. The method of claim 1, wherein: the temperature of the hydrogen reduction is 550-750 ℃, and the time is 2-4 hours.

Technical Field

The invention belongs to the technical field of uranium dioxide nano materials, and relates to a preparation method of a uranium dioxide nano material.

Background

At present, for the preparation of UO₂The precursors of the compound comprise uranyl nitrate, ammonium diuranate, tricarbonic acid oleamide, uranium peroxide and uranyl oxalate.

The uranyl nitrate solution is evaporated, denitrated and decomposed into UO₃Releasing nitrogen monoxide, nitrogen dioxide and other gases, and then using hydrogen to react UO₃Reduction to UO₂. Per 1mol of UO reduced₃25800 calories of heat are released, so the reaction can be automatically carried out after the reaction is started under the condition of large-scale production, and the method is most widely used.

Ammonium diuranate can be decomposed into UO by calcination₃At the temperature of more than 500 ℃, UO can be generated by gaseous hydrogen, ammonia and carbon monoxide₃Reduction to UO₂Reduction of UO at lower temperatures₃Prepared UO₂The material has active property, can spontaneously combust in the air and needs to be discharged under the protection of carbon dioxide.

Calcining uranium salt or other uranium oxide in air at 800 deg.C to obtain U₃O₈If it is to be UO₃Calcining to U₃O₈And then reduced to prepare UO₂The properties of (a) are more stable.

The uranyl tricarbonate amide crystal is put in a closed furnace for thermal decomposition to obtain UO₂。UO₂The physical properties such as particle structure, size and specific surface area are closely related to raw materials, methods and process conditions during preparation.

UO prepared by uranyl nitrate denitration and reduction₂The particles have small particle size, are dense and have small specific surface area. By cleavage of tricarbonamideReduced UO₂The particles have large particle size, are loose and porous and have large specific surface area.

Gao et al, by a hydrothermal method, react for 4 hours at 160 ℃ with uranyl acetate and ethylenediamine as raw materials to obtain nano-uranium dioxide; reacting for 24 hours at 240 ℃ by taking uranyl nitrate and tripropylamine as raw materials to obtain nano uranium dioxide; reacting for 18 hours at 200 ℃ by taking uranyl acetate and hydrazine hydrate as raw materials to obtain the nano uranium dioxide.

In summary, for UO₂The scientists have carried out a plurality of works, but aiming at the field of catalysis, the large-scale preparation of UO with controllable appearance, lighter agglomeration, uniform particle size and larger specific surface area₂The ceramic nano powder still faces great difficulty, so that the development of a new preparation method is urgent.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide a preparation method of a uranium dioxide nano material, so that UO with controllable morphology, light agglomeration, uniform particle size, high specific surface area and good catalytic activity can be prepared in a large scale₂Ceramic nano-powder.

In order to achieve the purpose, in a basic embodiment, the invention provides a preparation method of a uranium dioxide nano material, which comprises the steps of uniformly mixing a uranyl nitrate solution and a sodium hydroxide solution, adding the mixture into a reaction kettle for hydrothermal reaction, cooling a reaction product to room temperature, washing the reaction product with water until the pH value is 7.5-8.5, drying and grinding the reaction product, and placing the obtained powder into a tubular furnace to introduce hydrogen for reduction, so that the uranium dioxide nano material is prepared.

In a preferred embodiment, the invention provides a preparation method of uranium dioxide nano-materials, wherein the concentration of the uranyl nitrate solution is 0.5-1.0mol/L, the concentration of the sodium hydroxide solution is 5-8mol/L, and the mixing volume ratio of the uranyl nitrate solution to the sodium hydroxide solution is 1:20-1: 10.

In a preferred embodiment, the invention provides a preparation method of a uranium dioxide nano material, wherein the reaction kettle is a stainless steel high-temperature high-pressure reaction kettle taking polytetrafluoroethylene as a lining.

In a preferred embodiment, the invention provides a preparation method of a uranium dioxide nano material, wherein the temperature of the hydrothermal reaction is 80-100 ℃, the pressure is 0.6-0.8MPa, and the time is 18-48 hours.

In a preferred embodiment, the invention provides a preparation method of a uranium dioxide nano material, wherein the temperature of hydrogen reduction is 550-750 ℃ and the time is 2-4 hours.

The preparation method of the uranium dioxide nano material has the beneficial effects that (1) sodium hydroxide is used as a precipitator, and the sodium hydroxide is widely used, cheap and easy to prepare. (2) The sodium hydroxide is matched with a hydrothermal method, and is beneficial to obtaining UO with controllable large-scale morphology, lighter agglomeration, uniform particle size, higher specific surface area and good catalytic activity₂Ceramic nano-powder. (3) The hydrogen is used for reducing the intermediate product, so that the method is convenient and quick, and can obtain lower uranium-oxygen ratio.

Drawings

FIG. 1 is an XRD detection spectrum of intermediate products (before hydrogen reduction) of uranium dioxide nano-materials prepared in examples 1-3.

FIG. 2 is an XRD detection spectrum of the final product (after hydrogen reduction) of the uranium dioxide nano-material prepared in examples 1-3.

FIG. 3 is a scanning electron microscope detection spectrum of the final product of the uranium dioxide nanomaterial prepared in example 1.

FIG. 4 is a scanning electron microscope detection spectrum of the final product of the uranium dioxide nanomaterial prepared in example 2.

FIG. 5 is a scanning electron microscope detection spectrum of the final product of the uranium dioxide nanomaterial prepared in example 3.

Detailed Description

The present invention will be described in further detail with reference to the following examples and the accompanying drawings.