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

The invention relates to CO-CO₂Method for preparing superfine tungsten by reducing yellow tungsten, blue tungsten and purple tungsten with mixed gasA process for the preparation of a flour comprising the steps and conditions of: putting the raw materials into a furnace, and pushing a reaction boat to a position of a constant temperature zone; introducing Ar or CO before temperature rising₂The air in the furnace is evacuated, and then the temperature is raised to a roasting temperature set value between 500 ℃ and 1000 ℃ at the speed of 10 ℃/min and is switched into CO-CO₂Supplying gas by using the mixed gas; constant temperature roasting at 500-1000 deg.c CO-CO₂The CO content in the mixed atmosphere is 50-90% by volume; 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, wherein the mass loss rate of tungsten is within 21 percent.

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. CO-CO₂The method for preparing the superfine tungsten powder by reducing tungsten oxide in mixed atmosphere is characterized by comprising the following steps and conditions:

finally, the temperature is reduced and controlled, the mixed atmosphere is cut off, and protective gas Ar or CO is introduced₂Cooling to room temperature to obtain tungsten powder with particle size of 0.05-0.3 μm;

by adjusting CO-CO₂Preparing tungsten powder with different particle sizes according to the proportion of the mixed atmosphere;

the mass loss rate of the yellow tungsten, the blue tungsten and the purple tungsten is within 21 percent.

2. CO-CO according to claim 1₂The method for preparing the superfine tungsten powder by reducing tungsten oxide in mixed atmosphere is characterized by comprising the following steps: ar or CO with the flow rate of 500ml/min is introduced before the temperature is raised₂And (5) evacuating the air in the horizontal tube furnace.

3. CO-CO according to claim 1₂The method for preparing the superfine tungsten powder by reducing tungsten oxide in mixed atmosphere is characterized by comprising the following steps: finally, the temperature is reduced and controlled, the mixed atmosphere is cut off, and protective gas Ar or CO with the flow rate of 300ml/min is introduced₂。

4. CO-CO according to claim 1₂The method for preparing the superfine tungsten powder by reducing tungsten oxide in mixed atmosphere comprises the following steps: weighing 20g of yellow tungsten, putting the yellow tungsten into a reaction boat, and pushing the reaction boat to a furnace constant temperature zone; firstly setting the heating rate at 10 ℃/min, introducing 500ml/min Ar to evacuate air in the horizontal tubular furnace before heating, and introducing CO-CO when the temperature is raised to 1000 DEG C₂Mixed gas of 1800ml/min CO gas and 200ml/mCO of in₂Introducing gas into a mixed gas cylinder to form CO-CO₂Mixing the gas, and roasting for 2 hours; then cooling and cutting off CO-CO₂Mixing gas, switching to introduce 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.