Improvement method of tungsten trioxide reduction process

Abstract

The invention relates to an improvement method of a tungsten trioxide reduction process, which comprises the following steps: putting tungsten trioxide into a tubular furnace, and then introducing hydrogen to carry out reduction reaction to obtain tungsten powder; the reduction reaction comprises a first heating section, a first heat preservation section, a second heating section and a second heat preservation section which are sequentially carried out. The reduction reaction is carried out in multiple stages, the temperature gradient of the reduction reaction is controlled, the reduction efficiency is enhanced, and the situation that excessive condensate water is generated due to the fact that the temperature is directly increased to the highest temperature, and normal reaction is affected is avoided; according to the improvement method, a high-performance condenser does not need to be introduced, the equipment cost is reduced, and the performance of the obtained tungsten powder can also be guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of tungsten trioxide reduction, and in particular to an improved method for a tungsten trioxide reduction process. Background Art

[0002] Tungsten trioxide is an important semiconductor material, which is currently widely used in optoelectronic devices, catalysts, battery electrodes and other fields. Tungsten trioxide is also one of the main raw materials for preparing metallic tungsten powder. Through the tubular furnace reduction process, tungsten trioxide is reduced to tungsten powder using hydrogen at high temperature.

[0003] CN 115383128A discloses a method for preparing coarse-grained tungsten powder by reducing tungsten trioxide. Specifically, tungsten trioxide and tungsten hexachloride are placed in a ball mill according to a certain mass ratio and mixed evenly. Then the mixture of tungsten trioxide and tungsten hexachloride is placed in a reduction furnace. Hydrogen is introduced at a relatively low temperature for a first-stage reduction, so that the tungsten hexachloride is volatilized and reduced to metallic tungsten and deposited on the surface of the tungsten trioxide. Then, a mixed gas of hydrogen and water vapor is introduced at a high temperature for a second-stage intensive reduction, so as to promote the growth of tungsten powder particles, thereby preparing coarse-grained tungsten powder.

[0004] CN 109079151A discloses a method for preparing ultra-coarse tungsten powder by high-temperature liquid phase reduction of tungsten oxide. The method comprises the following steps: using tungsten oxide and tungsten powder as raw materials, wherein the particle sizes of the tungsten oxide and the tungsten powder are in the range of 0.2-1.0 μm, mixing the raw materials in a certain mass ratio, wherein the tungsten powder content is 0wt-10wt%, and putting the raw materials into a tubular furnace, introducing argon as a protective gas, and maintaining the temperature for 0-1h after the temperature rises to a set reduction temperature, then turning off the argon, and introducing pure hydrogen into the tubular furnace for reduction, wherein the reduction temperature is 1420-1600°C, and the holding time is 0.5-2.5h, thereby preparing ultra-coarse tungsten powder.

[0005] CN 111570818A discloses a novel reduction furnace with combinable heating belt length and a tungsten powder reduction method thereof, wherein the reduction furnace comprises a heating belt structure; the heating belt structure comprises a plurality of hollow refractory bricks distributed and arranged along the length direction of the furnace tube, each hollow refractory brick is respectively provided with a heating wire, and the heating wires of two adjacent hollow refractory bricks are connected in series through a switch; a plurality of thermocouples can be selectively provided between all two adjacent hollow refractory bricks, and each heating belt of the plurality of heating belts with varying heating belt lengths has a thermocouple. The invention can precisely match the temperature gradient of the reduction furnace and the temperature reaction time of the tungsten powder, so that the produced tungsten powder has the characteristics of uniform particle size distribution, less agglomeration, high crystallinity, etc.

[0006] The above invention uses a tubular furnace to reduce tungsten trioxide to obtain tungsten powder with better performance, but there are still defects in the tungsten trioxide reduction process: first, since a large amount of condensed water will be generated during the reaction, the condenser needs to have a higher cooling capacity, which increases the cost of the equipment; secondly, if the condensed water is not discharged in time, it may affect the normal progress of the reaction and even affect the quality of the product; in addition, excessive condensed water will also have a certain impact on the environment.

[0007] Therefore, how to effectively reduce the condensed water generated during the reduction of tungsten trioxide in a tubular furnace and reduce equipment costs is an urgent problem to be solved in this field. Summary of the invention

[0008] The purpose of the present invention is to provide an improved method for the reduction process of tungsten trioxide, which effectively solves the problem of excessive condensed water when reducing tungsten trioxide in a tubular furnace and reduces equipment costs.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] The present invention provides an improved method for tungsten trioxide reduction process, the improved method comprising the following steps:

[0011] Tungsten trioxide is placed in a tube furnace, and then hydrogen is introduced for reduction reaction to obtain tungsten powder; the reduction reaction includes a first heating stage, a first heat preservation stage, a second heating stage and a second heat preservation stage which are performed in sequence.

[0012] The improved method of tungsten trioxide reduction process provided by the present invention, compared with the traditional one-stage high-temperature reduction reaction, controls the temperature gradient of the reduction reaction by dividing the reduction reaction into multiple stages, effectively avoiding the excessive condensation water caused by directly heating to the highest temperature, thereby affecting the normal progress of the reaction; the improved method does not need to introduce a high-performance condenser, reduces the equipment cost, and the performance of the obtained tungsten powder can also be guaranteed.

[0013] Preferably, the heating rate of the first heating stage is 0.5-3°C / min, for example, it can be 0.5°C / min, 1°C / min, 1.5°C / min, 2°C / min or 3°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] Preferably, the end point of the first heating stage is 500-600°C, for example, 500°C, 520°C, 550°C, 580°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the insulation temperature of the first insulation section is 500-600°C, for example, it can be 500°C, 520°C, 550°C, 580°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the insulation time of the first insulation section is 30-120 min, for example, it can be 30 min, 50 min, 80 min, 100 min or 120 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the heating rate of the second heating stage is 2-5°C / min, for example, it can be 2°C / min, 2.5°C / min, 3°C / min, 4°C / min or 5°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the end point of the second heating stage is 890-910°C, for example, 890°C, 895°C, 900°C, 905°C or 910°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the insulation temperature of the second insulation section is 890-910°C, for example, it can be 890°C, 895°C, 900°C, 905°C or 910°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the insulation time of the second insulation section is 30-60 min, for example, it can be 30 min, 35 min, 40 min, 50 min or 60 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, a condensed water monitoring device is provided in the tubular furnace, and the condensed water monitoring device is connected to a condensed water pipe, and the condensed water pipe is used to discharge the condensed water generated by the reduction reaction.

[0022] As a preferred technical solution of the improved method of the present invention, the improved method comprises the following steps:

[0023] Put tungsten trioxide into a tube furnace, and then introduce hydrogen to perform a reduction reaction to obtain tungsten powder; the reduction reaction includes a first heating section, a first insulation section, a second heating section and a second insulation section, which are performed in sequence; the heating rate of the first heating section is 0.5-3°C / min, and the heating end point is 500-600°C; the insulation temperature of the first insulation section is 500-600°C, and the insulation time is 30-120min; the heating rate of the second heating section is 2-5°C / min, and the heating end point is 890-910°C; the insulation temperature of the second insulation section is 890-910°C, and the insulation time is 30-60min;

[0024] The tubular furnace is provided with a condensed water monitoring device, and the condensed water monitoring device is connected to a condensed water pipe, and the condensed water pipe is used to discharge the condensed water generated by the reduction reaction.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The improved method of tungsten trioxide reduction process provided by the present invention divides the reduction reaction into multiple stages, controls the temperature gradient of the reduction reaction, enhances the reduction efficiency, and avoids directly heating to the highest temperature to cause excessive condensed water to be generated, thereby affecting the normal progress of the reaction; the improved method does not need to introduce a high-performance condenser, reduces the equipment cost, and the performance of the obtained tungsten powder can also be guaranteed. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0028] Example 1

[0029] This embodiment provides an improved method for tungsten trioxide reduction process, and the improved method comprises the following steps:

[0030] Put tungsten trioxide into a tube furnace, and then introduce hydrogen to perform a reduction reaction to obtain tungsten powder; the reduction reaction includes a first heating section, a first insulation section, a second heating section and a second insulation section, which are performed in sequence; the heating rate of the first heating section is 2°C / min, and the heating end point is 550°C; the insulation temperature of the first insulation section is 550°C, and the insulation time is 80min; the heating rate of the second heating section is 4°C / min, and the heating end point is 900°C; the insulation temperature of the second insulation section is 900°C, and the insulation time is 40min;

[0031] The tubular furnace is provided with a condensed water monitoring device, and the condensed water monitoring device is connected to a condensed water pipe, and the condensed water pipe is used to discharge the condensed water generated by the reduction reaction.

[0032] The amount of condensed water produced in this embodiment was measured to be less than that produced in Comparative Example 1, and the performance of the obtained tungsten powder did not change significantly.

[0033] Example 2

[0034] This embodiment provides an improved method for tungsten trioxide reduction process, and the improved method comprises the following steps:

[0035] Put tungsten trioxide into a tube furnace, and then introduce hydrogen to perform a reduction reaction to obtain tungsten powder; the reduction reaction includes a first heating section, a first insulation section, a second heating section and a second insulation section, which are performed in sequence; the heating rate of the first heating section is 0.5°C / min, and the heating end point is 500°C; the insulation temperature of the first insulation section is 500°C, and the insulation time is 120min; the heating rate of the second heating section is 2°C / min, and the heating end point is 890°C; the insulation temperature of the second insulation section is 890°C, and the insulation time is 60min;

[0036] The tubular furnace is provided with a condensed water monitoring device, and the condensed water monitoring device is connected to a condensed water pipe, and the condensed water pipe is used to discharge the condensed water generated by the reduction reaction.

[0037] The amount of condensed water produced in this embodiment was measured to be less than that produced in Comparative Example 1, and the performance of the obtained tungsten powder did not change significantly.

[0038] Example 3

[0039] This embodiment provides an improved method for tungsten trioxide reduction process, and the improved method comprises the following steps:

[0040] Put tungsten trioxide into a tube furnace, and then introduce hydrogen to perform a reduction reaction to obtain tungsten powder; the reduction reaction includes a first heating section, a first insulation section, a second heating section and a second insulation section, which are performed in sequence; the heating rate of the first heating section is 3°C / min, and the heating end point is 600°C; the insulation temperature of the first insulation section is 600°C, and the insulation time is 30min; the heating rate of the second heating section is 5°C / min, and the heating end point is 910°C; the insulation temperature of the second insulation section is 910°C, and the insulation time is 30min;

[0041] The tubular furnace is provided with a condensed water monitoring device, and the condensed water monitoring device is connected to a condensed water pipe, and the condensed water pipe is used to discharge the condensed water generated by the reduction reaction.

[0042] The amount of condensed water produced in this embodiment was measured to be less than that produced in Comparative Example 1, and the performance of the obtained tungsten powder did not change significantly.

[0043] Example 4

[0044] This embodiment provides an improved method for tungsten trioxide reduction process. The difference from Embodiment 1 is that the heating rate of the first heating section is adjusted to 4°C / min, which is the same as the heating rate of the second heating section. The rest is the same as Embodiment 1.

[0045] In this embodiment, the heating rate of the first heating stage is too fast, and the amount of condensed water generated is measured to be less than that generated in Comparative Example 1, and the performance of the obtained tungsten powder is reduced.

[0046] Example 5

[0047] This embodiment provides an improved method for tungsten trioxide reduction process, which differs from Embodiment 1 in that the insulation temperature of the first insulation section is adjusted to 450° C., and the rest is the same as Embodiment 1.

[0048] In this embodiment, the insulation temperature of the first insulation section is too low, and the amount of condensed water generated is measured to be less than the amount of condensed water generated in Comparative Example 1, and the performance of the obtained tungsten powder is reduced.

[0049] Example 6

[0050] This embodiment provides an improved method for tungsten trioxide reduction process, which differs from Embodiment 1 in that the insulation temperature of the first insulation section is adjusted to 650° C., and the rest is the same as Embodiment 1.

[0051] In this embodiment, the insulation temperature of the first insulation section is too high, and the amount of condensed water generated is measured to be less than the amount of condensed water generated in Comparative Example 1, and the performance of the tungsten powder is slightly reduced.

[0052] Example 7

[0053] This embodiment provides an improved method for tungsten trioxide reduction process. The difference from Embodiment 1 is that the heating rate of the second heating section is adjusted to 2°C / min, which is the same as the heating rate of the first heating section. The rest is the same as Embodiment 1.

[0054] In this embodiment, the heating rate of the second heating stage is too slow, and the amount of condensed water generated is measured to be less than that generated in Comparative Example 1, and the performance of the tungsten powder is slightly reduced.

[0055] Comparative Example 1

[0056] This comparative example provides an improved method for the tungsten trioxide reduction process. The difference from Example 1 is that the reduction reaction is adjusted to a heating stage and a heat preservation stage performed sequentially, the heating rate is 4°C / min, the heating end point is 900°C, the heat preservation temperature is 900°C, the heat preservation time is 120min, and the rest is the same as Example 1.

[0057] In this comparative example, the reduction reaction is a conventional heating stage and a heat preservation stage, and a large amount of condensed water is generated, which will affect the normal progress of the reduction reaction.

[0058] In summary, the improved method of tungsten trioxide reduction process provided by the present invention divides the reduction reaction into multiple stages, controls the temperature gradient of the reduction reaction, enhances the reduction efficiency, and avoids directly heating to the highest temperature to cause excessive condensation water, thereby affecting the normal progress of the reaction; the improved method does not need to introduce a high-performance condenser, reduces the equipment cost, and the performance of the obtained tungsten powder can also be guaranteed.

[0059] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. An improved method for tungsten trioxide reduction process, characterized in that: The improved method comprises the following steps: Tungsten trioxide is placed in a tube furnace, and then hydrogen is introduced for reduction reaction to obtain tungsten powder; the reduction reaction includes a first heating stage, a first heat preservation stage, a second heating stage and a second heat preservation stage which are performed in sequence.

2. The improved method according to claim 1, characterized in that: The heating rate of the first heating stage is 0.5-3°C / min; Preferably, the temperature rise end point of the first temperature rise section is 500-600°C.

3. The improved method according to claim 1 or 2, characterized in that: The insulation temperature of the first insulation section is 500-600°C.

4. The improved method according to any one of claims 1 to 3, characterized in that: The insulation time of the first insulation section is 30-120 minutes.

5. The improved method according to any one of claims 1 to 4, characterized in that: The heating rate of the second heating stage is 2-5°C / min.

6. The improved method according to any one of claims 1 to 5, characterized in that: The end point of the second heating stage is 890-910°C.

7. The improved method according to any one of claims 1 to 6, characterized in that: The insulation temperature of the second insulation section is 890-910°C.

8. The improved method according to any one of claims 1 to 7, characterized in that: The insulation time of the second insulation section is 30-60 minutes.

9. The improved method according to any one of claims 1 to 8, characterized in that: The tubular furnace is provided with a condensed water monitoring device, and the condensed water monitoring device is connected to a condensed water pipe, and the condensed water pipe is used to discharge the condensed water generated by the reduction reaction.

10. The improved method according to any one of claims 1 to 9, characterized in that: The improved method comprises the following steps: Put tungsten trioxide into a tube furnace, and then introduce hydrogen to perform a reduction reaction to obtain tungsten powder; the reduction reaction includes a first heating section, a first insulation section, a second heating section and a second insulation section, which are performed in sequence; the heating rate of the first heating section is 0.5-3°C / min, and the heating end point is 500-600°C; the insulation temperature of the first insulation section is 500-600°C, and the insulation time is 30-120min; the heating rate of the second heating section is 2-5°C / min, and the heating end point is 890-910°C; the insulation temperature of the second insulation section is 890-910°C, and the insulation time is 30-60min; The tubular furnace is provided with a condensed water monitoring device, and the condensed water monitoring device is connected to a condensed water pipe, and the condensed water pipe is used to discharge the condensed water generated by the reduction reaction.