Device and method for reducing metal oxide through hydrogen metallurgy

Abstract

The embodiment of the invention relates to a device and method for reducing metal oxide through hydrogen metallurgy, and belongs to the technical field of metallurgy. The embodiment of the invention aims to solve the technical problems of large hydrogen flow, serious waste, high cost and long reduction process period in the existing hydrogen metallurgical industry. The device for reducing the metal oxide through hydrogen metallurgy comprises a furnace body, a furnace tube is arranged in the furnace body in a penetrating mode, the two ends of the furnace tube extend out of the furnace body and are fixed through a furnace tube support, and the furnace tube support is fixedly arranged on the furnace body; a graphite crucible assembly and a furnace plug are sequentially arranged in the furnace tube from bottom to top, and a gap exists between the graphite crucible assembly and the furnace plug. According to the device provided by the embodiment of the invention, the inside of the graphite crucible is firstly filled with the reducing gas hydrogen, the lower gas guide cover enables the hydrogen entering the graphite crucible to be dispersed in the material, and the unreacted gas is blocked by the gas guide cover above the graphite crucible, flows back in the graphite crucible, participates in the reaction again and is reused, so that the reaction efficiency is improved. The hydrogen utilization rate is effectively improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of metallurgical technology, and in particular, to a device and method for hydrogen metallurgical reduction of metal oxides. Background Art

[0002] The transformation of the metallurgical industry towards high quality and low carbonization has become an inevitable development trend. Among them, hydrogen metallurgical technology is a new green and low-carbon metallurgical technology in the metallurgical industry. It is the most promising and inevitable development direction to replace coke metallurgy and significantly reduce carbon dioxide emissions in the metallurgical process.

[0003] Hydrogen is a non-polluting, widely available, highly efficient and reducible gas. It can significantly reduce carbon dioxide emissions during the metallurgical process and achieve low-carbon or even zero-carbon emission goals. In addition, as a reducing agent, hydrogen also has significant advantages such as accelerating reduction reactions and improving metallurgical efficiency. To this end, countries are committed to developing hydrogen metallurgical technology that "replaces carbon with hydrogen" to get rid of dependence on "carbon metallurgy" and achieve new metallurgical technologies that are efficient, clean and sustainable. At present, the use of hydrogen reduction in steel metallurgy is still in the exploratory stage, and there are few reports of successful industrial cases.

[0004] For small varieties of rare metals (tungsten, molybdenum, indium, etc.), most of them can be prepared by directly reducing their metal oxides through hydrogen metallurgy. Taking the preparation of metallic molybdenum as an example, molybdenum is an important refractory metal, which is mainly used in the production of molybdenum-based alloys and non-ferrous metal composite materials. It is mainly prepared by reducing its oxides with hydrogen. The production cost, quality and performance of the reduction process mainly depend on the hydrogen flow rate, material layer thickness, temperature, etc. in the production process. However, hydrogen metallurgical technology is also facing many problems at present, and reducing costs is one of the key issues. Hydrogen is a relatively high-cost secondary energy source, and the cost of green hydrogen is even higher. At present, in the hydrogen smelting process, the amount of hydrogen used is large, the contact with the material is insufficient, and the waste is serious, which not only leads to high cost of the reduction process, but also a long reduction production cycle. The existing Chinese patent with publication number CN201289294Y discloses a hydrogen reduction furnace for processing ultrafine metal tungsten powder. By increasing the length of the furnace tube, four temperature control zones are provided on the furnace tube so that the temperature in the furnace can be controlled to reduce tungsten oxide to prepare metal tungsten powder. However, there are problems of large hydrogen flow and serious waste during the reduction process. The existing Chinese patent with authorization publication number CN107199348B discloses a tungsten oxide hydrogen reduction system, which includes a reduction furnace device, a hydrogen condensation and dehydration device and a drying device connected end to end to form a loop, which can effectively reduce the difficulty of workers' operation and reduce equipment costs compared to traditional technologies. However, the problems of large hydrogen consumption, low utilization rate and serious waste have not been solved. Summary of the invention

[0005] In view of this, the embodiments of the present application provide an apparatus and method for reducing metal oxides by hydrogen metallurgy. Through the gas flow path design of the vertical tubular furnace and the fine processing of the graphite crucible assembly, hydrogen can directly enter the graphite crucible to fully contact the material and undergo a reduction reaction. At the same time, the unreacted hydrogen can reflux in the graphite crucible to be further fully utilized, thereby greatly improving the utilization rate of hydrogen, ensuring that the material is fully reduced, and shortening the reduction production cycle, thereby solving the problems of large hydrogen flow, serious waste, high cost and long reduction process cycle in the existing hydrogen metallurgical industry.

[0006] In a first aspect, an embodiment of the present application provides a device for reducing metal oxides by hydrogen metallurgy, comprising a furnace body, wherein a furnace tube is inserted into the furnace body, and both ends of the furnace tube extend outside the furnace body and are fixed by a furnace tube bracket, wherein the furnace tube bracket is fixedly arranged on the furnace body; a graphite crucible assembly and a furnace plug are sequentially arranged in the furnace tube from bottom to top, and there is a gap between the graphite crucible assembly and the furnace plug;

[0007] It also includes a hollow support, the hollow support is used to support the graphite crucible assembly to be fixed in the furnace tube, and the hollow support is also used to introduce reaction gas into the graphite crucible assembly;

[0008] The graphite crucible assembly comprises a graphite crucible, which is a cylindrical structure with openings at both ends. Both ends of the graphite crucible are provided with gas guide covers, and the gas guide covers are provided with dense sieve-like through holes.

[0009] In some embodiments, which may include the above embodiments, the hollow pillar is disposed flush with the bottom of the graphite crucible.

[0010] In some embodiments that may include the above embodiments, the gas guide cover is provided with a protrusion toward the inside of the graphite crucible, the protrusion is adapted to the port of the graphite crucible, the protrusion is connected to the gas guide cover, and dense sieve-like through holes are also provided around the protrusion.

[0011] In some embodiments that may include the above embodiments, an external thread is further provided around the protruding portion, the graphite crucible port is provided with an internal thread matched with the external thread, and the protrusion and the graphite crucible are threadedly connected.

[0012] In some embodiments, which may include the above embodiments, the diameter of the through hole is less than 10 mm.

[0013] In some embodiments, which may include the above embodiments, the hollow struts are stainless steel struts.

[0014] In some embodiments that may include the above embodiments, the furnace tube is a quartz tube, and a vacuum gauge is also provided on the furnace body.

[0015] A second aspect of the embodiment of the present application further provides a method for reducing metal oxides by hydrogen metallurgy, using the above-mentioned device for reducing metal oxides by hydrogen metallurgy, comprising the following steps:

[0016] Step 1: placing the metal oxide powder to be reduced in a graphite crucible, and covering both ends of the graphite crucible with gas guide covers, and then placing the covered graphite crucible into a device for hydrogen metallurgical reduction of metal oxides containing a hollow pillar;

[0017] Step 2: The lower end of the graphite crucible is horizontally placed on a hollow support, the furnace is evacuated, and the air in the furnace is replaced with an inert gas;

[0018] Step 3: After the inert gas replacement in step 2 is completed, the reducing gas H2 is introduced into the graphite crucible through the hollow pillar, and the heating system of the hydrogen metallurgical reduction device of the metal oxide is turned on to maintain the temperature after reaching a certain temperature, and then the reduction reaction is carried out;

[0019] Step 4: Pour the metal powder obtained by reduction in step 3 out of the graphite crucible and collect it to obtain a single metal powder.

[0020] It should be noted that the present application is different from the conventional tubular furnace in which the reducing gas first enters the furnace tube and then penetrates into the crucible to react with the material. The present application effectively increases production capacity and improves production efficiency. The present application can set the reaction temperature and heating rate according to the conventional reduction temperature of the metal oxide, and set the hydrogen flow rate according to the mass of the metal oxide to be reduced. By regulating the reduction parameters (reduction temperature, heating rate, hydrogen flow rate), the particle size of the metal powder after reduction can be controlled, and after collection, vibration particle size screening can be performed.

[0021] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0022] 1. In the embodiment of the present application, the structural design of the hydrogen metallurgical reduction device for metal oxides is adopted. The reducing gas hydrogen first fills the inside of the graphite crucible. The gas guide cover at the bottom disperses the hydrogen entering the graphite crucible in the material. The unreacted gas is blocked by the gas guide cover at the top. The unreacted gas refluxes in the graphite crucible, re-participates in the reaction, and is reused, thereby effectively improving the utilization rate of hydrogen.

[0023] 2. In the embodiment of the present application, the structural design of the hydrogen metallurgical reduction device for metal oxides allows hydrogen to directly enter the graphite crucible, fully contact the material and undergo a reduction reaction, thereby ensuring that the material is fully reduced while shortening the reduction production cycle; at the same time, the unreacted hydrogen is refluxed in the graphite crucible to be further fully utilized, greatly improving the utilization rate of hydrogen and solving the problems of large hydrogen flow, serious waste and high cost in the hydrogen metallurgical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Schematic diagram of gas flow dispersion in the furnace tube of the embodiment of the present application;

[0026] Figure 2 A cross-sectional view of a device for hydrogen metallurgical reduction of metal oxides according to an embodiment of the present application;

[0027] Figure 3 A schematic diagram of the side structure of the gas guide cover according to an embodiment of the present application;

[0028] Figure 4 A schematic diagram of the front structure of the gas guide cover according to an embodiment of the present application;

[0029] Figure 5 A sample of metal Cu powder prepared by reducing CuO in Example 2 of the present application;

[0030] Figure 6 SEM image of metallic Mo powder prepared by reducing MoO in Example 3 of the present application;

[0031] Figure 7 Figure 4 of the present application shows a sample of metallic Fe powder prepared by reducing Fe2O3.

[0032] Description of reference numerals:

[0033] 1. Furnace tube; 2. Furnace tube bracket; 3. Graphite crucible; 4. Gas guide cover; 5. Furnace plug; 6. Hollow pillar; 7. Through hole. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] It should be explained that hydrogen metallurgy is a smelting method that uses hydrogen to replace carbon or other reducing agents used in traditional metallurgy to reduce various metal oxides to produce metals through chemical reactions. This method can reduce carbon dioxide emissions from the source and is an important way to achieve low-carbon metallurgy and significantly reduce carbon dioxide emissions.

[0036] Unless otherwise specified, the experimental methods used in the examples of this application are all conventional methods.

[0037] In the following examples, unless otherwise specified, all raw materials can be obtained by commercial purchase or conventional methods.

[0038] Example 1

[0039] like Figure 1-4 As shown, an embodiment of the present application provides a device for hydrogen metallurgical reduction of metal oxides, including a furnace body, a furnace tube 1 is penetrated in the furnace body, both ends of the furnace tube 1 extend outside the furnace body and are fixed by furnace tube brackets 2, and the furnace tube brackets 2 are fixedly arranged on the furnace body; a graphite crucible assembly and a furnace plug 5 are arranged in sequence from bottom to top in the furnace tube 1, a stainless steel pipe is connected to the air outlet at the upper end of the furnace tube 1, and the furnace plug 5 is fixedly connected to the stainless steel pipe by threads to realize the fixation of the furnace plug 5 in the furnace tube 1, and there is a gap between the graphite crucible assembly and the furnace plug 5.

[0040] Furthermore, it also includes a hollow pillar 6, which is used to support the graphite crucible assembly to be fixed in the furnace tube 1, and the hollow pillar 6 is also used to introduce reaction gas into the graphite crucible assembly; illustratively, the hollow pillar 6 is a stainless steel pillar.

[0041] Specifically, the graphite crucible assembly includes a graphite crucible 3, which is a cylindrical structure with openings at both ends. The height of the graphite crucible 3 is adjusted according to the charge mass and the heating temperature zone of the tubular furnace, and is preferably 300 mm or 500 mm; gas guide covers 4 are provided at both ends of the graphite crucible 3, and dense sieve-like through holes 7 are provided on the gas guide covers 4.

[0042] Exemplarily, the hollow pillar 6 is arranged flush with the bottom of the graphite crucible 3 , which can effectively ensure that the hydrogen enters the graphite crucible 3 in a dispersed manner from the through holes 7 on the gas guide cover 4 at the bottom of the graphite crucible 3 .

[0043] Furthermore, the gas flow guide cover 4 is provided with a projection toward the inside of the graphite crucible 3, and the projection is adapted to the port of the graphite crucible 3. Preferably, the projection is cylindrical, and more preferably, the height of the projection is 8-30 mm; the projection is connected to the gas flow guide cover 4, and dense sieve-like through holes 7 are also provided around the projection; illustratively, the diameter of the through holes 7 is less than 10 mm, preferably less than 5 mm, and more preferably less than 3 mm. While the graphite crucible 3 acts as a loading container and a heating element during the smelting process, the design of the projection and the sieve-like through hole gas flow guide cover can disperse the gas flow entering the graphite crucible 3 in the graphite crucible 3 and fully react with the material; at the same time, the graphite crucible 3 can reflux the reaction gas passing through the graphite crucible 3, prolong the contact time between the gas and the material, and reduce the waste of raw gas.

[0044] Specifically, an external thread is provided around the protruding part, and an internal thread matching the external thread is provided at the port of the graphite crucible 3. The protrusion and the graphite crucible 3 are threadedly connected, which is convenient for disassembly and assembly for loading, unloading and other operations.

[0045] Furthermore, the furnace tube 1 is a quartz tube, and a vacuum gauge is also provided on the furnace body. The vacuum gauge is a prior art and will not be described in detail in this application.

[0046] In addition, the hollow pillar 6 and the graphite crucible assembly can be disassembled and replaced as the use time increases, which can effectively avoid equipment pollution and reduce equipment maintenance costs.

[0047] Example 2

[0048] The method for reducing copper oxide by hydrogen metallurgy in this embodiment adopts the device for reducing metal oxide by hydrogen metallurgy in Embodiment 1, and comprises the following steps:

[0049] Step 1: Place 10 g of CuO powder to be reduced in a graphite crucible, cover both ends of the graphite crucible with gas guide covers, and then place the covered graphite crucible into a device for hydrogen metallurgical reduction of metal oxides (i.e., a vertical tube furnace) containing a hollow pillar;

[0050] Step 2: The lower end of the graphite crucible is horizontally placed on a hollow support, and the furnace is evacuated. When the vacuum gauge of the furnace body shows less than 800Pa, argon gas is used to replace the air in the furnace, and the replacement cycle is repeated 5 times;

[0051] Step 3: After the argon replacement in step 2 is completed, the reducing gas H2 is introduced into the graphite crucible through the hollow pillar at a flow rate of 40 ml / min, and the tubular furnace heating system is turned on at 10°C / min to reach the required temperature of 500°C for reduction, and the temperature is kept for 90 minutes to carry out the reduction reaction;

[0052] Step 4: Pour the copper powder obtained by reduction in step 3 out of the graphite crucible and collect it. After vibration particle size screening, the Cu powder with the required particle size can be obtained. The metal Cu powder sample is shown in the figure Figure 5 shown.

[0053] Example 3

[0054] The method for hydrogen metallurgical reduction of molybdenum oxide in this embodiment adopts the device for hydrogen metallurgical reduction of metal oxide in Example 1, comprising the following steps:

[0055] Step 1: Place 10 g of MoO2 powder to be reduced in a graphite crucible, cover both ends of the graphite crucible with gas guide covers, and then place the covered graphite crucible into a device for hydrogen metallurgical reduction of metal oxides (i.e., a vertical tube furnace) containing a hollow pillar;

[0056] Step 2: The lower end of the graphite crucible is horizontally placed on a hollow support, and the furnace is evacuated. When the vacuum gauge of the furnace body shows less than 800Pa, argon gas is used to replace the air in the furnace, and the replacement cycle is repeated 5 times;

[0057] Step 3: After the argon replacement in step 2 is completed, the reducing gas H2 is introduced into the graphite crucible through the hollow pillar at a flow rate of 60 ml / min, and the tubular furnace heating system is turned on at 10°C / min to reach the required temperature of 1000°C for reduction, and the temperature is kept for 120 minutes to carry out the reduction reaction;

[0058] Step 4: Pour the metal molybdenum powder obtained by reduction in step 3 out of the graphite crucible and collect it. After vibration particle size screening, Mo powder with required particle size can be obtained. The SEM image of the metal Mo powder is as follows: Figure 6 shown.

[0059] Example 4

[0060] The device and method for reducing ferric oxide by hydrogen metallurgy in this embodiment adopts the device for reducing metal oxide by hydrogen metallurgy in Embodiment 1, and comprises the following steps:

[0061] Step 1: Place 10 g of Fe2O3 powder to be reduced in a graphite crucible, cover both ends of the graphite crucible with gas guide covers, and then place the covered graphite crucible into a device for hydrogen metallurgical reduction of metal oxides (i.e., a vertical tube furnace) containing a hollow pillar;

[0062] Step 2: The lower end of the graphite crucible is horizontally placed on a hollow support, and the furnace is evacuated. When the vacuum gauge of the furnace body shows less than 800Pa, argon gas is used to replace the air in the furnace, and the replacement cycle is repeated 5 times;

[0063] Step 3: After the argon replacement in step 2 is completed, the reducing gas H2 is introduced into the graphite crucible through the hollow pillar at a flow rate of 60 ml / min, and the tubular furnace heating system is turned on at 10°C / min to reach the required temperature of 900°C for reduction, and the temperature is kept for 90 minutes for reduction reaction;

[0064] Step 4: Pour out the elemental Fe powder obtained by reduction in step 3 from the graphite crucible and collect it. After vibration particle size screening, Fe powder with required particle size can be obtained. The metal Fe powder sample is shown in the figure Figure 7 shown.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A device for hydrogen metallurgical reduction of metal oxides, characterized in that: The furnace body comprises a furnace tube, the furnace body is penetrated by a furnace tube, the two ends of the furnace tube extend outside the furnace body and are fixed by a furnace tube bracket, and the furnace tube bracket is fixedly arranged on the furnace body; a graphite crucible assembly and a furnace plug are arranged in sequence from bottom to top in the furnace tube, and there is a gap between the graphite crucible assembly and the furnace plug; It also includes a hollow support, the hollow support is used to support the graphite crucible assembly to be fixed in the furnace tube, and the hollow support is also used to introduce reaction gas into the graphite crucible assembly; The graphite crucible assembly comprises a graphite crucible, which is a cylindrical structure with openings at both ends. Both ends of the graphite crucible are provided with gas guide covers, and the gas guide covers are provided with dense sieve-like through holes.

2. The device for hydrogen metallurgical reduction of metal oxides according to claim 1, characterized in that: The hollow pillar is arranged flush with the bottom of the graphite crucible.

3. The device for hydrogen metallurgical reduction of metal oxides according to claim 1, characterized in that: The gas guide cover is protruded toward the inside of the graphite crucible, the protrusion is matched with the port of the graphite crucible, the protrusion is connected with the gas guide cover, and dense sieve-like through holes are also arranged around the protrusion.

4. The device for hydrogen metallurgical reduction of metal oxides according to claim 3, characterized in that: The protrusion is also provided with external threads around it, the port of the graphite crucible is provided with internal threads matching the external threads, and the protrusion and the graphite crucible are threadedly connected.

5. The device for hydrogen metallurgical reduction of metal oxides according to claim 3, characterized in that: The diameter of the through hole is less than 10 mm.

6. The device for hydrogen metallurgical reduction of metal oxides according to claim 1, characterized in that: The hollow support is a stainless steel support.

7. The device for hydrogen metallurgical reduction of metal oxides according to claim 1, characterized in that: The furnace tube is a quartz tube, and a vacuum gauge is also arranged on the furnace body.

8. A method for hydrogen metallurgical reduction of metal oxides, characterized in that: The device for metallurgical reduction of metal oxides using hydrogen according to any one of claims 1 to 7 comprises the following steps: Step 1: placing the metal oxide powder to be reduced in a graphite crucible, and covering both ends of the graphite crucible with gas guide covers, and then placing the covered graphite crucible into a device for hydrogen metallurgical reduction of metal oxides containing a hollow pillar; Step 2: The lower end of the graphite crucible is horizontally placed on a hollow support, the furnace is evacuated, and the air in the furnace is replaced with an inert gas; Step 3: After the inert gas replacement in step 2 is completed, the reducing gas H2 is introduced into the graphite crucible through the hollow pillar, and the heating system of the hydrogen metallurgical reduction device of the metal oxide is turned on to maintain the temperature after reaching a certain temperature, and then the reduction reaction is carried out; Step 4: Pour the metal powder obtained by reduction in step 3 out of the graphite crucible and collect it to obtain a single metal powder.

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