阅读说明：本技术 一种铝热法生产钨的硼化物的方法 (Method for producing boride of tungsten by thermit process ) 是由 张洪涛 于 2020-07-28 设计创作，主要内容包括：一种铝热法生产钨的硼化物的方法,将三氧化钨粉、三氧化二硼粉和铝粉混料器中混合均匀,装入真空自蔓延炉的石英坩埚中,抽至真空后,关闭真空泵；启动循环水泵,确保真空自蔓延炉的炉体持续水循环；将反应炉中钨丝送电,加热至1000℃—1200℃,引燃铝粉,自蔓延反应开始进行,炉内压力接近0Pa时,启动H150滑阀真空泵,抽至真空；反应结束后,待炉内温度降至50℃,关闭循环水泵；出炉,精整,得到钨的硼化物块体。本发明通过铝热还原法及自蔓延法实现了生产周期短、产量高、节能的目标,工艺一步完成,生产成本低,且产品纯度高。合成在密闭的真空反应器中进行,解决了还原成品易氧化的问题,生产过程环保。(A method for producing tungsten boride by an aluminothermic process comprises the steps of uniformly mixing tungsten trioxide powder, diboron trioxide powder and aluminum powder in a mixer, filling the mixture into a quartz crucible of a vacuum self-propagating furnace, vacuumizing the quartz crucible, and then closing a vacuum pump; starting a circulating water pump to ensure the continuous water circulation of the furnace body of the vacuum self-propagating furnace; the tungsten wire in the reaction furnace is powered on and heated to 1000-1200 ℃, aluminum powder is ignited, the self-propagating reaction starts, and when the pressure in the furnace is close to 0Pa, an H150 slide valve vacuum pump is started and is pumped to vacuum; after the reaction is finished, the circulating water pump is closed when the temperature in the furnace is reduced to 50 ℃; discharging and finishing to obtain the tungsten boride block. The invention realizes the aims of short production period, high yield and energy saving by an aluminothermic reduction method and a self-propagating method, and has the advantages of one-step completion of the process, low production cost and high product purity. The synthesis is carried out in a closed vacuum reactor, the problem that the reduction finished product is easy to oxidize is solved, and the production process is environment-friendly.)

1. A method for producing tungsten boride by an aluminothermic method is characterized by comprising the following steps: the method comprises the following specific steps:

feeding raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder according to a stoichiometric ratio, wherein the particle size of tungsten trioxide is 325 meshes, the particle size of diboron trioxide is 325 meshes, and mixing the materials in a 250-liter V-shaped mixer for more than 5 hours to obtain a uniform mixed material;

(2) the uniform mixed materials are produced into the boride of tungsten by adopting a vacuum self-propagating furnace, the vacuum self-propagating furnace comprises a furnace body and a furnace cover, a cooling water jacket I and a cooling water jacket II are respectively arranged on the furnace body and the furnace cover, a water outlet I communicated with the cooling water jacket I is arranged at the upper part of the furnace body, a water inlet I communicated with the cooling water jacket I is arranged at the lower part of the furnace body, a vacuum pipeline is arranged at the top of the furnace body, and the vacuum pipeline is connected with a vacuum pump; a water outlet II and a water inlet II which are communicated with the cooling water jacket II are respectively arranged at the top of the furnace cover, a pair of electrodes are fixed on the furnace cover and positioned on the outer side of the cooling water jacket II, and tungsten filaments are arranged on the two electrodes and extend into the crucible; an explosion-proof valve is arranged on the outer wall of the furnace body; circulating water pumps are respectively arranged on the water inlet I and the water inlet II; putting the uniform mixed material obtained in the step (1) into a quartz crucible of a vacuum self-propagating furnace, closing a furnace cover, transmitting power to start a vacuum pump, pumping till the vacuum degree reaches 1-3 Pa, and stopping power; starting circulating water pumps arranged on the water inlet I and the water inlet II to ensure the continuous water circulation of the furnace body of the vacuum self-propagating furnace and cool the aluminothermic reaction furnace body for later use;

(3) the method comprises the steps of feeding power to a tungsten wire in a reaction furnace, heating to 1000-1200 ℃, igniting aluminum powder, starting a self-propagating reaction, immediately observing a vacuum gauge of the self-propagating furnace, starting a vacuum pump when the pressure in the furnace is close to 0Pa, pumping to a vacuum degree of 1-3 Pa, and preventing material oxidation caused by opening a furnace cover;

(4) after the reaction in the step (3) is finished, the temperature in the furnace is reduced to 50 DEG CClosing circulating water pumps arranged on the water inlet I and the water inlet II; discharging to obtain layered boride of tungsten and Al₂O₃Separating out the upper layer of aluminum oxide; finishing, namely grinding the aluminum oxide adhered to the surface of the tungsten boride by using a corneometer to obtain the tungsten boride block.

2. The aluminothermic process for producing borides of tungsten according to claim 1, characterized in that: the granularity of the aluminum powder is less than or equal to 200 meshes so as to ensure high reduction efficiency.

3. The aluminothermic process for producing borides of tungsten according to claim 1, characterized in that: the electrode power of the heating tungsten wire is more than 5 kw.

4. The aluminothermic process for producing borides of tungsten according to claim 1, characterized in that: when producing tungsten boride, the molar ratio of the raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder is 2:1: 6.

5. The aluminothermic process for producing borides of tungsten according to claim 1, characterized in that: when producing tungsten diboride, the molar ratio of the raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder is 1:1: 4.

6. The aluminothermic process for producing borides of tungsten according to claim 1, characterized in that: when producing tungsten pentaboride, the molar ratio of the raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder is 4:5: 18.

7. The aluminothermic process for producing borides of tungsten according to claim 1, characterized in that: the purity of the tungsten trioxide is 99.9 percent, the purity of the boron trioxide is 99.5 percent, and the purity of the aluminum powder is 99.8 percent.

8. The aluminothermic process for producing borides of tungsten according to claim 1, characterized in that: the vacuum pump is an H150 slide valve vacuum pump.

Technical Field

The invention relates to a method for producing tungsten boride by an aluminothermic process, in particular to a method for producing tungsten boride by an aluminothermic process, which is widely applied to the industries of structural materials, wear-resistant materials, electrode materials and the like.

Background

The W-B compound has high melting point, high hardness, high conductivity, wear resistance, high temperature resistance and corrosion resistance, and has neutron and gamma ray comprehensive shielding performance, so that the W-B compound is widely applied to the fields of structural materials, wear-resistant materials, electrode materials and the like. The tungsten boride (molecular formula WB) has the excellent performance of a W-B compound, and has wide future application prospect.

At present, the method for synthesizing W-B series compounds is less, the main method is a high-temperature high-pressure synthesis method of tungsten and boron, the composition of the synthesized tungsten boride phase is complex, and a single phase cannot be obtained, so that the difficulty in preparing the tungsten boride compound with high purity is higher. And the synthesis temperature is higher, which causes the volatilization loss of boron powder and increases the production cost.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for producing tungsten boride by an aluminothermic method, realizes the aims of short production period, high yield and energy conservation by an aluminothermic reduction method and a self-propagating method, and has the advantages of one-step completion of the process, low production cost and high product purity. The synthesis is carried out in a closed vacuum reactor, the problem that the reduction finished product is easy to oxidize is solved, and the production process is environment-friendly.

The technical scheme of the invention is as follows:

a method for producing boride of tungsten by a thermit process comprises the following steps:

feeding raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder according to a stoichiometric ratio, wherein the particle size of tungsten trioxide is 325 meshes, the particle size of diboron trioxide is 325 meshes, and mixing the materials in a 250-liter V-shaped mixer for more than 5 hours to obtain a uniform mixed material;

(2) the uniform mixed materials are produced into the boride of tungsten by adopting a vacuum self-propagating furnace, the vacuum self-propagating furnace comprises a furnace body and a furnace cover, a cooling water jacket I and a cooling water jacket II are respectively arranged on the furnace body and the furnace cover, a water outlet I communicated with the cooling water jacket I is arranged at the upper part of the furnace body, a water inlet I communicated with the cooling water jacket I is arranged at the lower part of the furnace body, a vacuum pipeline is arranged at the top of the furnace body, and the vacuum pipeline is connected with an H150 slide valve vacuum pump; a water outlet II and a water inlet II which are communicated with the cooling water jacket II are respectively arranged at the top of the furnace cover, a pair of electrodes are fixed on the furnace cover and positioned on the outer side of the cooling water jacket II, and tungsten filaments are arranged on the two electrodes and extend into the crucible; an explosion-proof valve is arranged on the outer wall of the furnace body; circulating water pumps are respectively arranged on the water inlet I and the water inlet II; putting the uniform mixed material obtained in the step (1) into a quartz crucible of a vacuum self-propagating furnace, closing a furnace cover, transmitting power to start an H150 slide valve vacuum pump, pumping till the vacuum degree reaches 1 Pa-3 Pa, and stopping power; starting circulating water pumps arranged on the water inlet I and the water inlet II to ensure the continuous water circulation of the furnace body of the vacuum self-propagating furnace and cool the aluminothermic reaction furnace body for later use;

(3) the method comprises the steps of feeding power to a tungsten wire in a reaction furnace, heating to 1000-1200 ℃, igniting aluminum powder, starting a self-propagating reaction, immediately observing a vacuum gauge of the self-propagating furnace, starting an H150 slide valve vacuum pump when the pressure in the furnace is close to 0Pa, pumping to a vacuum degree of 1-3 Pa, and preventing the material from being oxidized due to opening of a furnace cover;

(4) after the reaction in the step (3) is finished, closing circulating water pumps arranged on the water inlet I and the water inlet II when the temperature in the furnace is reduced to 50 ℃; discharging to obtain layered boride of tungsten and Al₂O₃Separating out the upper layer of aluminum oxide; finishing, namely grinding the aluminum oxide adhered to the surface of the tungsten boride by using a corneometer to obtain the tungsten boride block.

Furthermore, the granularity of the aluminum powder is less than or equal to 200 meshes so as to ensure high reduction efficiency.

Further, the electrode power of the heating tungsten wire is more than 5 kw.

Further, when producing tungsten boride, the molar ratio of the raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder is 2:1: 6.

Further, when producing tungsten diboride, the molar ratio of the raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder is 1:1: 4.

Further, when producing tungsten pentaboride, the molar ratio of the raw materials of tungsten trioxide powder, diboron trioxide powder and aluminum powder is 4:5: 18.

Further, the purity of the tungsten trioxide is 99.9%, the purity of the diboron trioxide is 99.5%, and the purity of the aluminum powder is 99.8%.

By adopting the technical scheme, the method has the following beneficial effects:

the method for producing the boride of tungsten by the thermit method realizes the aims of short production period, high yield and energy conservation by the thermit reduction method and the self-propagating method, and has the advantages of one-step completion of the process, low production cost and high product purity. The synthesis is carried out in a closed vacuum reactor, the problem that the reduction finished product is easy to oxidize is solved, and the production process is environment-friendly. The high-purity tungsten boride compounds with molecular formulas of WB, WB2, W2B5 and the like can be prepared by adjusting the raw material adding proportion, and the process is controllable.

Drawings

FIG. 1 is a schematic structural view of an apparatus for producing tungsten boride according to the present invention;

in the figure: 1-furnace body, 2-furnace cover, 3-crucible, 4-cooling water jacket I, 5-water outlet I, 6-water inlet I, 7-cooling water jacket II, 8-water outlet II, 9-water inlet II, 10-vacuum pipeline, 11-H150 slide valve vacuum pump, 12-electrode, 13-tungsten filament and 14-explosion-proof valve.

FIG. 2 is an X-ray diffraction pattern of WB of the present invention (corresponding to example 1);

FIG. 3 is a report of the particle size distribution of WB of the present invention (corresponding to example 1);

FIG. 4 is a schematic diagram of WB (corresponding to example 1) according to the present invention.

Detailed Description

The present invention will be explained in more detail by the following examples, but the present invention is not limited to the following examples.

Firstly, the following description is made on the raw materials in the following three embodiments, and the description thereof will not be repeated in the following cases:

a. tungsten trioxide powder with the granularity of 325 meshes and the purity of 99.9 percent;

b. diboron trioxide powder with the granularity of 325 meshes and the purity of 99.5 percent;

c. aluminum powder with a particle size of 200 meshes or less and a purity of 99.8%.