阅读说明：本技术 一种大比表面纳米氧化镧的制备方法 (Preparation method of large-specific-surface nano lanthanum oxide ) 是由 王鹭 于 2021-08-20 设计创作，主要内容包括：本发明属于新材料领域,特别涉及一种大比表面纳米氧化镧的制备方法。称取顺-9-十八碳烯酸加入氯化镧溶液中并使其均匀分散,然后滴加氢氧化钠溶液后,采用水浴加热反应釜水浴陈化,水浴结束后进行水洗,再用乙醇均匀浸润氢氧化镧并抽干,取出灼烧。本发明在短时间内能控制颗粒为纳米级又解决了氢氧化镧生成后因料水不分离,无法进行水洗除杂质的问题。顺-9-十八碳烯酸的加入能包裹并控制沉淀离子的生长速度,可以使过饱和度控制在适当范围内,从而达到控制粒子生长均匀的目的。通过乙醇清洗对颗粒所带结晶水和游离水也有部分去除,并有利于提高颗粒分散性。(The invention belongs to the field of new materials, and particularly relates to a preparation method of large-specific-surface nano lanthanum oxide. Weighing cis-9-octadecenoic acid, adding into lanthanum chloride solution, uniformly dispersing, dropwise adding sodium hydroxide solution, heating in water bath, aging in water bath in a reaction kettle, washing with water after water bath is finished, uniformly soaking lanthanum hydroxide with ethanol, drying, taking out, and firing. The invention can control the particles to be nano-scale in a short time and solves the problem that the water cannot be washed to remove impurities because the material and the water are not separated after the lanthanum hydroxide is generated. The addition of cis-9-octadecenoic acid can wrap and control the growth speed of the precipitated ions, and can control the supersaturation degree in a proper range, thereby achieving the purpose of controlling the uniform growth of particles. The ethanol washing also partially removes the crystal water and the free water carried by the particles, and is beneficial to improving the particle dispersibility.)

1. A preparation method of nano lanthanum oxide with large specific surface area is characterized by comprising the following steps: firstly, weighing cis-9-octadecenoic acid, adding the cis-9-octadecenoic acid into a lanthanum chloride solution, and uniformly dispersing the cis-9-octadecenoic acid; then, sodium hydroxide solution is dripped into the mixture by adopting positive precipitation; and after the dropwise addition is finished, the reaction kettle is heated in a water bath for water bath aging, water washing is carried out after the water bath is finished, the lanthanum hydroxide is uniformly soaked in ethanol and is dried by pumping, and the lanthanum hydroxide is taken out for burning.

2. The method for preparing the nano lanthanum oxide with the large specific surface area as claimed in claim 1, wherein the addition amount of the cis-9-octadecenoic acid is 20-30% of the mass of the metered lanthanum oxide.

3. The method for preparing nano lanthanum oxide with large specific surface area according to claim 1, wherein the molar ratio of lanthanum chloride to sodium hydroxide is 1: 3-1: 3.5.

4. the method for preparing nano lanthanum oxide with large specific surface area according to claim 1, wherein the water bath temperature is 60-70 ℃ and the aging time is 4 hours.

5. The method for preparing nano lanthanum oxide with large specific surface area according to claim 1, wherein the firing temperature is 800 ℃, and the temperature is kept for 3-5 hours.

6. The nano lanthanum oxide with large specific surface area prepared by the method of any one of claims 1 to 5, wherein the nano lanthanum oxide has a particle size of 30 to 100nm and a BET of 30 to 40 m/g.

Technical Field

The invention belongs to the field of new materials, and particularly relates to a preparation method of large-specific-surface nano lanthanum oxide.

Background

The rare earth element has a unique 4f electronic structure, a large atomic magnetic moment and the like, so that the rare earth element has a plurality of excellent properties such as optical, magnetic, electric and catalytic properties. Many researchers have used rare earth elements as additives to improve the properties of materials. Lanthanum oxide belongs to rare earth oxide, is one of important products in light rare earth, and has good physical and chemical properties, so the lanthanum oxide is widely applied to the fields of civil use, military use, high technology and the like. For example, lanthanum oxide is widely applied in the fields of rare earth glass, ceramics, catalysts, fluorescent powder, lasers, heating elements, cathode materials, reduction of exhaust emission and the like.

The nanometer lanthanum oxide has small particles, the activity of the nanometer lanthanum oxide is higher than that of other rare earth elements, and the nanometer preparation method of other elements cannot be used for reference to prepare the nanometer lanthanum oxide. In order to prepare the nanometer lanthanum oxide with uniformity, the patent CN111017980A adopts a hydrothermal method, the equipment needs high temperature and high pressure, and the reaction time needs 90 hours. Also, the sol-gel method takes 48 hours for preparation, and the current methods are not favorable for production, have too long reaction time, have low yield due to equipment limitation and have too high cost.

Disclosure of Invention

The invention aims to overcome the defects of the existing production method and provide a preparation method of nano lanthanum oxide which is easy to produce.

The preparation method of the large specific surface area nano lanthanum oxide comprises the following steps: firstly, cis-9-octadecenoic acid is weighed and added into a lanthanum chloride solution to be uniformly dispersed in the lanthanum chloride. Then, sodium hydroxide solution is dropwise added by adopting a normal precipitation method. After the dropwise addition, the reaction kettle is heated in a water bath for aging. And (4) after the water bath is finished, washing with water, uniformly infiltrating lanthanum hydroxide with ethanol, drying by pumping, taking out and firing.

Wherein the addition amount of cis-9-octadecenoic acid is 20-30% of the mass of the metered lanthanum oxide.

The molar ratio of lanthanum chloride to sodium hydroxide is 1: 3-1: 3.5, too little results in non-molding of the particles, and too much results in poor dispersibility of the particles.

The water bath temperature is 60-70 ℃, and the aging time is 4 hours.

The temperature range has little influence on the growth of particles during aging, has better effect on the activity of cis-9-octadecenoic acid, can better separate lanthanum hydroxide from water in slurry, and can better clean chlorine radicals and free alkali. And the packing of lattice bases in each particle is minimized.

The washing time is about 4 hours, and the required effect can be achieved.

Soaking lanthanum hydroxide in ethanol, stirring thoroughly, and pumping to dry. As cis-9-octadecenoic acid is wrapped on the surface of the particles, a small part of crystal water is remained, and caustic soda of lanthanum oxide is affected, so that the product quality does not reach the standard. The influence of cis-9-octadecenoic acid on causticizing alkali of lanthanum oxide is solved by ethanol cleaning.

The burning temperature is 800 ℃, and the heat preservation time is 3-5 hours.

Has the advantages that:

(1) the preparation method has the advantages that a high-temperature high-pressure reaction kettle is not needed, the reaction preparation time is shortened, the particles can be controlled to be nanoscale in a short time, and the problem that impurities cannot be removed by water washing due to the fact that material water is not separated after lanthanum hydroxide is generated is solved.

(2) Cis-9-octadecenoic acid is added into the raw material, can wrap and control the growth speed of the precipitated ions, and can control the supersaturation degree in a proper range, thereby achieving the purpose of controlling the uniform growth of particles.

(3) The ethanol washing also partially removes the crystal water and the free water carried by the particles, and is beneficial to improving the particle dispersibility.

Description of the drawings:

FIG. 1 is an SEM image of lanthanum oxide prepared in example 1;

FIG. 2 is an SEM image of lanthanum oxide prepared in example 2;

FIG. 3 is an SEM image of lanthanum oxide prepared in example 3;

FIG. 4 is an SEM photograph of lanthanum oxide prepared in comparative example 2;

FIG. 5 is an SEM photograph of lanthanum oxide prepared in comparative example 3;

fig. 6 is an SEM image of lanthanum oxide prepared in comparative example 4.

Detailed Description

The present invention will be described in detail with reference to specific examples.

Example 1

10KG lanthanum oxide is prepared.

Firstly weighing 2KG cis-9-octadecenoic acid, adding into 0.4mol/L lanthanum chloride solution, and uniformly dispersing in lanthanum chloride. Then, 0.6mol/L sodium hydroxide solution is dropwise added into the solution by adopting a positive precipitation method, wherein the molar ratio of lanthanum chloride to sodium hydroxide is 1: 3.1. after the dropwise addition, the temperature in the reaction kettle is controlled by adopting a water bath at 60 ℃ for aging for 4 hours, and the reaction kettle is washed for about 4 hours after the water bath is finished. Then the lanthanum hydroxide is evenly soaked by 2KG ethanol and finally the lanthanum hydroxide is pumped to dryness. Taking out and putting into a cart furnace. The temperature is 800 ℃, and the temperature is kept for 5 hours.

The obtained nano lanthanum oxide has the particle size of 30-100nm, good particle dispersibility, BET: 35 m/g. Chloride is less than 50ppm, sodium ion is less than 200ppm, and LOI is less than 1.

Example 2

Preparation of 10KG lanthanum oxide

Firstly, 3KG cis-9-octadecenoic acid is weighed and added into a 0.4mol/L lanthanum chloride solution, and the solution is uniformly dispersed in the lanthanum chloride. Then, 0.6mol/L sodium hydroxide solution is dropwise added into the solution by adopting a positive precipitation method, wherein the molar ratio of lanthanum chloride to sodium hydroxide is 1: 3.5. after the dropwise addition, the temperature in the reaction kettle is controlled by adopting a 70 ℃ water bath for aging for 4 hours, and the reaction kettle is washed for about 3.5 hours after the water bath is finished. Then the lanthanum hydroxide is evenly soaked by 2KG ethanol and finally the lanthanum hydroxide is pumped to dryness. Taking out and putting into a cart furnace, keeping the temperature at 800 ℃ for 4 hours.

The obtained nano lanthanum oxide has the particle size of 30-100nm, good particle dispersibility, BET: 28 m/g. Chloride is less than 50ppm, sodium ion is less than 200ppm, and LOI is less than 1.

Example 3

10KG lanthanum oxide is prepared.

Firstly weighing 2.5KG cis-9-octadecenoic acid, adding into 0.4mol/L lanthanum chloride solution, and uniformly dispersing in lanthanum chloride. Then, 0.6mol/L sodium hydroxide solution is dropwise added into the solution by adopting a positive precipitation method, wherein the molar ratio of lanthanum chloride to sodium hydroxide is 1: 3.3. after the dropwise addition, the temperature in the reaction kettle is controlled by adopting a water bath at 60 ℃ for aging for 4 hours, and the reaction kettle is washed for about 4 hours after the water bath is finished. Then the lanthanum hydroxide is evenly soaked by 2KG ethanol and finally the lanthanum hydroxide is pumped to dryness. Taking out and putting into a cart furnace at the temperature of 800 ℃, and preserving heat for 3 hours.

The obtained nano lanthanum oxide has the particle size of 30-100nm, good particle dispersibility, BET: 31 m/g. Chloride is less than 50ppm, sodium ion is less than 200ppm, and LOI is less than 1.

Comparative example 1

10KG lanthanum oxide is prepared.

And (2) dropwise adding 0.6mol/L sodium hydroxide solution into 0.4mol/L lanthanum chloride solution by adopting a positive precipitation method, wherein the molar ratio of lanthanum chloride to sodium hydroxide is 1: 3.1. after the dropwise addition, the temperature in the reaction kettle is controlled by adopting a water bath at 60 ℃ for aging for 4 hours, and after the water bath is finished, the reaction kettle is washed by water, so that a precipitated product is in a rice milk state, and the lanthanum hydroxide and the water are difficult to separate, and the production and the preparation cannot be carried out.

Comparative example 2

The addition amount of cis-9-octadecenoic acid is 1KG, and the water washing time is about 6 hours. The rest is the same as example 1.

The particle diameter of the nanometer lanthanum oxide obtained by burning is 50-150 nm. BET: 15 m/g. 1100ppm of chloride, 2300ppm of sodium ions and LOI less than 1.

Comparative example 3

The addition amount of cis-9-octadecenoic acid is 4KG, and the water washing time is about 3 hours. The rest is the same as example 1.

The particle diameter of the nanometer lanthanum oxide obtained by burning is 30-100 nm. BET of 26 m/g. Chloride is less than 50ppm, sodium is less than 200ppm, and LOI is 2.1.

Comparative example 4

10KG lanthanum oxide is prepared.

Firstly weighing 2KG cis-9-octadecenoic acid, adding into 0.4mol/L lanthanum chloride solution, and uniformly dispersing in lanthanum chloride. Then, 0.6mol/L sodium hydroxide solution is dropwise added into the solution by adopting a positive precipitation method, wherein the molar ratio of lanthanum chloride to sodium hydroxide is 1: 3.1. after the dropwise adding is finished, the temperature in the reaction kettle is controlled by adopting a water bath at 60 ℃ for aging for 4 hours, and after the water bath is finished, the reaction kettle is washed for about 4 hours and finally drained. Taking out and putting into a cart furnace at the temperature of 800 ℃ for 5 hours.

The particle size of the nanometer lanthanum oxide obtained by burning is 30-100nm, the particle dispersibility is better, and the BET: 25 m/g. Chloride is less than 50pm, sodium is less than 200ppm, and LOI is 5.1.