CN108907218B

CN108907218B - CO-CO2Method for preparing superfine tungsten powder by reducing tungsten oxide in mixed atmosphere

Info

Publication number: CN108907218B
Application number: CN201810830094.3A
Authority: CN
Inventors: 姜平国; 刘文杰; 肖义钰; 廖春发; 邱廷省
Original assignee: Jiangxi University of Science and Technology
Current assignee: Jiangxi University of Science and Technology
Priority date: 2018-07-26
Filing date: 2018-07-26
Publication date: 2021-11-19
Anticipated expiration: 2038-07-26
Also published as: CN108907218A

Abstract

本发明涉及CO‑CO₂混合气体还原黄钨、蓝钨、紫钨制备超细钨粉的方法，包括以下步骤和条件：将原料放进炉子，反应舟推至恒温带位置；升温前通Ar或CO₂排空炉中空气，然后按10℃/min的速率升温至500‑1000℃间的焙烧温度设定值时切换成CO‑CO₂混合气体供气；恒温焙烧，还原焙烧温度为500‑1000℃间的设定值，焙烧时CO‑CO₂混合气氛中CO含量为50％‑90％体积比；焙烧还原时间为1‑2小时；最后降温控制，切断混合气氛，通入保护气体Ar或CO₂，温度降到室温即得到粒度为0.05‑0.3μm的钨粉，钨的质量损失率在21％以内。The invention relates to a method for preparing ultrafine tungsten powder by reducing yellow tungsten, blue tungsten and violet tungsten with CO-CO ₂ mixed gas. Or CO ₂ to evacuate the air in the furnace, then switch to CO-CO ₂ mixed gas supply when heating up to the calcination temperature set value between 500-1000 ℃ at a rate of 10 ℃/min; constant temperature calcination, the reduction calcination temperature is 500 The set value between ‑1000℃, the CO content in the CO‑CO ₂ mixed atmosphere during roasting is 50%‑90% by volume; the roasting reduction time is 1‑2 hours; the final cooling control is performed, the mixed atmosphere is cut off, and protective gas is introduced Ar or CO ₂ , and the temperature drops to room temperature to obtain tungsten powder with a particle size of 0.05-0.3 μm, and the mass loss rate of tungsten is within 21%.

Description

CO-CO2Method for preparing superfine tungsten powder by reducing tungsten oxide in mixed atmosphere

Technical Field

The invention relates to a preparation technology of ultrafine tungsten powder, in particular to CO-CO₂A method for preparing ultrafine tungsten powder by reducing yellow tungsten, blue tungsten and purple tungsten by mixed gas.

Background

Tungsten ore resources in China are very rich, the tungsten ore is mainly scheelite in type, the reserves are huge, the tungsten ore occupies more than half of the total reserves in the world, and the tungsten ore plays an important role in development and utilization of the tungsten resources and industrial production. The method has extremely important and irreplaceable application in the fields of national defense industry, aerospace industry, mechanical manufacturing industry and the like. At present, the yellow tungsten, the blue tungsten and the purple tungsten can be used for preparing the superfine tungsten powder by hydrogen reduction, but the superfine tungsten powder prepared by taking the purple tungsten as a raw material has the most excellent performance from the aspect of product performance, the blue tungsten is inferior, and finally the yellow tungsten is used. Therefore, the process for preparing the ultrafine tungsten powder by using hydrogen to reduce the purple tungsten basically in the industry produces the ultrafine tungsten powder under the conditions of a thin material layer and large hydrogen flow, and has unstable quality and low production efficiency.

Disclosure of Invention

The invention aims to provide CO-CO₂Method for preparing superfine tungsten powder by reducing tungsten oxide in mixed atmosphere by using CO-CO₂The tungsten powder with the granularity of 0.05-0.3 mu m can be prepared by reducing yellow tungsten, blue tungsten and purple tungsten by the mixed gas.

The reduction roasting temperature, the heat preservation time and the CO-CO of the yellow tungsten, the blue tungsten and the purple tungsten₂The proportion of mixed atmosphere and the flow rate of gas are different, and the prepared tungsten powder has different particle sizes.

The technical scheme of the invention is as follows: CO-CO₂The method for preparing the superfine tungsten powder by reducing tungsten oxide in mixed atmosphere comprises the following steps and conditions:

firstly, putting raw materials into a furnace, putting yellow tungsten or blue tungsten or purple tungsten into a reaction boat, and pushing the reaction boat to a constant temperature zone position of a reaction tube in a horizontal tube furnace;

secondly, the temperature is increased, and Ar or CO is introduced before the temperature is increased₂Evacuating air in the horizontal tubular furnace, heating the furnace at a rate of 10 ℃/min, and switching to CO-CO when the temperature is raised to a roasting temperature set value between 500 ℃ and 1000 DEG C₂Supplying gas by using the mixed gas;

then constant temperature roasting is carried out again, the reduction roasting temperature is a set value between 500 ℃ and 1000 ℃, and CO-CO is generated during roasting₂The CO content in the mixed atmosphere is 50-90% by volume; CO 2₂The gas flow is 50-200ml/min, the CO gas flow is 50-1800ml/min, and the roasting reduction time is 1-2 hours;

finally, the temperature is reduced and controlled, the mixed atmosphere is cut off, and protective gas Ar or CO is introduced₂And cooling to room temperature to obtain tungsten powder with the particle size of 0.05-0.3 mu m.

The method has the advantages of short process flow, simple equipment, no pollution and good economic benefit. Can use CO-CO at lower cost₂The yellow tungsten, the blue tungsten and the purple tungsten are directly reduced in the mixed atmosphere, the mass loss rate of the yellow tungsten, the blue tungsten and the purple tungsten is within 21 percent, and the prepared tungsten powder with the granularity of 0.05-0.3 mu m has uniform granularity and excellent appearance.

Detailed Description

Example 1: 20g of yellow tungsten is weighed into a reaction boat and pushed to a furnace constant temperature zone. Firstly, the heating rate is set at 10 ℃/min, and 500ml/min CO is introduced before heating₂Evacuating air, introducing 200ml/min CO gas and 200ml/min CO when the roasting temperature reaches 500 deg.C₂Gas, baking time 2 hours. Then cooling, cutting off CO gas flow, and continuously introducing 300ml/min protective gas CO₂And the temperature is reduced to room temperature. Under the condition, the mass loss rate of the yellow tungsten is 20.7 percent, and the obtained tungsten powder has the granularity of 0.05-0.1 mu m and accounts for 82.8 percent.

Practice ofExample 2: 20g of blue tungsten is weighed into a reaction boat and pushed to a furnace constant temperature zone. Firstly setting the heating rate at 10 ℃/min, introducing 500ml/min Ar to exhaust air before heating, and introducing CO-CO when the roasting temperature reaches 800 DEG C₂Mixing gas, wherein 800ml/min of CO gas and 200ml/min of CO gas are mixed₂Introducing gas into a mixed gas cylinder to form CO-CO₂And (4) mixing the gases. The calcination time was 1.5 hours. Then cooling and cutting off CO-CO₂And (4) mixing the gases, switching to and introducing 300ml/min of protective gas Ar, and cooling to room temperature. Under the condition, the mass loss rate of blue tungsten is 20.1 percent, and the obtained tungsten powder has the granularity of 0.05-0.1 mu m and accounts for 90.1 percent.

Example 3: 20g of purple tungsten is weighed and put into a reaction boat and pushed to a furnace constant temperature zone. Firstly, the heating rate is set at 10 ℃/min, and 500ml/min CO is introduced before heating₂Evacuating air, introducing 1400ml/min CO gas and 200ml/min CO when the roasting temperature is 900 deg.C₂Gas, baking time 1 hour. Then cooling, cutting off CO gas flow, and continuously introducing 300ml/min protective gas CO₂And the temperature is reduced to room temperature. Under the condition, the mass loss rate of the purple tungsten is 19.1 percent, and the obtained tungsten powder has the granularity of 0.05-0.1 mu m and accounts for 96.2 percent.

Example 4: 20g of yellow tungsten is weighed into a reaction boat and pushed to a furnace constant temperature zone. Firstly setting the heating rate at 10 ℃/min, introducing 500ml/min Ar to exhaust air before heating, and introducing CO-CO when the roasting temperature reaches 1000 DEG C₂Mixing gas, wherein 1800ml/min CO gas and 200ml/min CO gas are mixed₂Introducing gas into a mixed gas cylinder to form CO-CO₂Mixing the gas, and roasting for 2 hours. Then cooling and cutting off CO-CO₂And (4) mixing the gases, switching to and introducing 300ml/min of protective gas Ar, and cooling to room temperature. Under the condition, the mass loss rate of the yellow tungsten is 20.7 percent, and the obtained tungsten powder has the granularity of 0.05-0.2 mu m and accounts for 97.1 percent.

Claims

1. a CO- _CO mixed atmosphere reduction tungsten oxide prepares the method for ultrafine tungsten powder, it is characterized in that, comprise the following steps and conditions:

First put the raw material into the furnace, place yellow tungsten or blue tungsten or purple tungsten in the reaction boat, and push the reaction boat to the constant temperature zone position of the reaction tube in the horizontal tube furnace;

Secondly, heat up, evacuate the air in the horizontal tube furnace by passing Ar or CO ₂ before the temperature rise, then heat up the furnace at a rate of 10°C/min, and switch to CO- CO ₂ mixed gas supply;

Roasting at constant temperature again, the reduction roasting temperature is the set value between 500-1000 ° C, the CO content in the CO-CO ₂ mixed atmosphere during roasting is 50%-90% volume ratio; the CO ₂ gas flow rate is 50-200ml/min, The CO gas flow is 50-1800ml/min, and the roasting reduction time is 1-2 hours;

Finally, the temperature is controlled, the mixed atmosphere is cut off, the protective gas Ar or CO ₂ is introduced, and the temperature is lowered to room temperature to obtain tungsten powder with a particle size of 0.05-0.3 μm;

Tungsten powder with different particle sizes can be prepared by adjusting the ratio of CO-CO ₂ mixed atmosphere;

The mass loss rate of yellow tungsten, blue tungsten and purple tungsten is within 21%.

2. a kind of CO-CO according to claim ₁ mixed atmosphere reduction tungsten oxide prepares the method for ultra-fine tungsten powder, it is characterized in that: before heating up, the flow rate of feeding is 500ml/min Ar or CO ₂ emptying horizontal type Air in a tube furnace.

3. a kind of CO-CO according to claim ₁ The method for preparing ultrafine tungsten powder by reducing tungsten oxide in mixed atmosphere, is characterized in that: the last temperature control is controlled, and the mixed atmosphere is cut off, and the inflow flow is the protective gas of 300ml/min Ar or CO ₂ .

4. a kind of CO-CO according to claim ₁ The method for preparing ultrafine tungsten powder by reducing tungsten oxide in mixed atmosphere, is embodied as: take 20g yellow tungsten and put it into the reaction boat, and push it to the constant temperature zone of the furnace; The rate was set at ₁₀ °C/min, and the air in the horizontal tube furnace was evacuated by passing 500ml/min of Ar before the temperature rise. The _CO2 gas of /min is passed into the mixed gas bottle to form a CO- _CO2 mixed gas, and the roasting time is 2 hours; then the temperature is lowered, the CO- _CO2 mixed gas is cut off, and the protective gas Ar of 300ml/min is switched and passed in, and the temperature is lowered to room temperature ; Under this condition, the mass loss rate of yellow tungsten is 20.7%, and the particle size of the obtained tungsten powder is 0.05-0.2 μm, accounting for 97.1%.