An apparatus and method for hydrogen metallurgy to reduce metal oxides

Abstract

The embodiment of the present application relates to a device and method for hydrogen metallurgy to reduce metal oxides, belonging to the technical field of metallurgy. The embodiment of the present application aims to solve the technical problems of large hydrogen flow rate, serious waste, high cost and long reduction process cycle in the existing hydrogen metallurgy industry. The device for hydrogen metallurgy to reduce metal oxides in the embodiment of the present application includes a furnace body, a furnace tube is penetrated in the furnace body, and both ends of the furnace tube extend outside the furnace body and are fixed by 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 there is a gap between the graphite crucible assembly and the furnace plug. For the device provided by the embodiment of the present application, the reducing gas hydrogen first fills the inside of the graphite crucible, and the gas diversion cover below disperses the hydrogen entering the graphite crucible in the material. The unreacted gas is blocked by the gas diversion cover above the graphite crucible and refluxes in the graphite crucible to participate in the reaction again and be reused, effectively improving the hydrogen utilization rate.

Description

Technical Field

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

[0002] With the national strategic goal of "carbon peaking and carbon neutrality" and the promulgation and implementation of relevant policies, the transformation of the metallurgical industry towards high quality and low carbon has become an inevitable development trend. Among them, hydrogen metallurgy technology is a new green and low-carbon metallurgy technology in the metallurgical industry, and 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 gas with no pollution, wide sources, high efficiency and good reducibility. It can significantly reduce carbon dioxide emissions in the metallurgical process and achieve the goal of low-carbon or even zero-carbon emissions. Moreover, as a reducing agent, hydrogen also has significant advantages such as accelerating the reduction reaction and improving metallurgical efficiency. Therefore, various countries are committed to researching and developing hydrogen metallurgy technology of "replacing carbon with hydrogen" to get rid of the dependence on "carbon metallurgy" and achieve a new metallurgy technology with high efficiency, cleanliness and sustainable development. At present, the use of hydrogen reduction in iron and steel metallurgy is still in the exploratory stage, and there are few reported industrial success cases. It can be seen that hydrogen metallurgy reduction technology is a major challenge faced by China and even the world.

[0004] For small varieties of rare metals (such as tungsten, molybdenum, indium, etc.), at present, most of them can be directly reduced by hydrogen metallurgy to prepare their metal oxides. Taking the preparation of metal molybdenum as an example, molybdenum is an important refractory metal, mainly used in the production of molybdenum-based alloys and non-ferrous metal composite materials, etc. It is mainly prepared by reducing its oxide with hydrogen. The production cost, quality and performance of the reduction process mainly depend on the hydrogen flow rate, material layer thickness, temperature, etc. during the production process. However, at present, hydrogen metallurgy technology also faces many problems, and reducing costs is one of the key issues. Hydrogen is a secondary energy source with relatively high costs, and the cost of green hydrogen is even higher. In the current hydrogen smelting process, the amount of hydrogen used is large, the contact with the material is insufficient, and the waste is serious. This not only leads to high costs in the reduction process, but also a long reduction production cycle. The Chinese patent with the publication number CN201289294Y discloses a hydrogen reduction furnace for processing ultrafine metal tungsten powder. By increasing the length of the furnace tube and providing four temperature control zones on the furnace tube, the temperature in the furnace can be controlled to reduce tungsten oxide to prepare metal tungsten powder. It has the problem of large hydrogen flow rate and serious waste during the reduction process; the Chinese patent with the authorized 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 operation difficulty of workers and can reduce equipment costs compared with traditional technologies, but still does not solve the problems of large hydrogen consumption, low utilization rate and serious waste. 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 further provided on the furnace body.

[0015] The second aspect of the embodiments of the present application further provides a method for hydrogen metallurgy to reduce metal oxides. Using the above device for hydrogen metallurgy to reduce metal oxides, it includes the following steps:

[0016] Step 1: Place the metal oxide powder to be reduced in a graphite crucible, cover both ends of the graphite crucible with a gas diversion cover, and then place the covered graphite crucible into the device for hydrogen metallurgy to reduce metal oxides containing a hollow support column;

[0017] Step 2: Horizontally place the lower end of the graphite crucible on the hollow support column, evacuate the furnace chamber, and displace the air in the furnace chamber with an inert gas;

[0018] Step 3: After the inert gas displacement in Step 2 is completed, introduce the reducing gas H2 into the graphite crucible through the hollow support column. At the same time, turn on the heating system of the device for hydrogen metallurgy to reduce metal oxides and keep it at a certain temperature for heat preservation to carry out the reduction reaction;

[0019] Step 4: Pour out and collect the metal powder obtained by reduction in Step 3 from the graphite crucible to obtain the metal elemental powder.

[0020] It should be noted that this application is different from the conventional way of the reduction gas first entering the furnace tube and then infiltrating into the crucible to react with the material. This application effectively increases production capacity and improves production efficiency; this application can set the reaction temperature and heating rate according to the conventional reduction temperature of the metal oxide, and set the hydrogen gas flow rate introduced according to the mass of the metal oxide to be reduced. By adjusting the reduction parameters (reduction temperature, heating rate, hydrogen gas flow rate), the particle size of the reduced metal powder can be controlled, and after collection, vibration particle size screening can be carried out.

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

[0022] 1. In the embodiments of the present application, through the structural design of the device for hydrogen metallurgy to reduce metal oxides, the reducing gas hydrogen first fills the inside of the graphite crucible. The gas diversion cover below disperses the hydrogen entering the graphite crucible in the material. Blocked by the gas diversion cover above, the unreacted gas refluxes in the graphite crucible and participates in the reaction again for reuse, effectively improving the hydrogen utilization rate;

[0023] 2. In the embodiments of the present application, through the structural design of the hydrogen metallurgy reduction metal oxide device, hydrogen directly enters the graphite crucible to fully contact the material and undergo a reduction reaction. While ensuring that the material is fully reduced, the reduction production cycle is shortened. At the same time, the unreacted hydrogen refluxes in the graphite crucible to be further fully utilized, greatly improving the utilization rate of hydrogen, and solving the problems of large hydrogen flow rate, serious waste, and high cost in the hydrogen metallurgy industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

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

[0026] Figure 2 Cross-sectional view of the device for hydrogen metallurgy reduction of metal oxides in the embodiments of the present application;

[0027] Figure 3 Schematic side view of the gas diversion cover in the embodiments of the present application;

[0028] Figure 4 Schematic front view of the gas diversion cover in the embodiments of the present application;

[0029] Figure 5 Sample diagram of the metal Cu powder prepared by reducing CuO in Embodiment 2 of the present application;

[0030] Figure 6 SEM diagram of the metal Mo powder prepared by reducing MoO in Embodiment 3 of the present application;

[0031] Figure 7 Sample diagram of the metal Fe powder prepared by reducing Fe2O3 in Embodiment 4 of the present application.

[0032] Description of the reference numerals:

[0033] 1. Furnace tube; 2. Furnace tube support; 3. Graphite crucible; 4. Gas diversion cover; 5. Furnace plug; 6. Hollow support; 7. Through hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[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 gas 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] Further, the gas guide cover 4 protrudes into the interior of the graphite crucible 3, and the protrusion is adapted to the port of the graphite crucible 3. Preferably, the protruding part is cylindrical, and more preferably, the height of the protruding part is 8-30 mm; the protruding part is communicated with the gas guide cover 4, and a dense sieve-shaped through hole 7 is also arranged around the protruding part; Exemplarily, the diameter of the through hole 7 is less than 10 mm, preferably less than 5 mm, and more preferably less than 3 mm. While the graphite crucible 3 functions as a charging container and a heating element during the smelting process, through the design of the protruding part and the sieve-shaped through hole gas guide cover, the airflow entering the graphite crucible 3 can be dispersed in the graphite crucible 3, fully reacting with the material; at the same time, the graphite crucible 3 can make the reaction gas passing through the graphite crucible 3 flow back, prolonging the contact time between the gas and the material and reducing the waste of raw material gas.

[0044] Specifically, an external thread is further arranged around the protruding part, and an internal thread adapted to the external thread is arranged at the port of the graphite crucible 3. The protruding part and the graphite crucible 3 are threadedly connected, which is convenient for disassembly and assembly for operations such as charging and discharging.

[0045] Further, the furnace tube 1 is a quartz tube, and a vacuum gauge is also arranged on the furnace body. The vacuum gauge is a prior art and will not be elaborated herein.

[0046] In addition, the hollow support 6 and the graphite crucible assembly can be detachably replaced as the usage time prolongs, which can effectively avoid equipment contamination and reduce equipment maintenance costs.

[0047] Example 2

[0048] The method for hydrogen metallurgy to reduce copper oxide in this example uses the device for hydrogen metallurgy to reduce metal oxides in Example 1, and includes the following steps:

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

[0050] Step 2: Horizontally place the lower end of the graphite crucible on the hollow support, evacuate the furnace chamber. When the vacuum gauge on the furnace body shows less than 800 Pa, then use argon to replace the air in the furnace chamber, and circulate the replacement 5 times.

[0051] Step 3: After the argon replacement in Step 2 is completed, introduce the reducing gas H2 into the graphite crucible through the hollow support at a flow rate of 40 ml / min. At the same time, start the heating system of the tube furnace at 10 °C / min, reach the required reduction temperature of 500 °C, and keep it warm for 90 min to carry out the reduction reaction.

[0052] Step 4. Pour out and collect the copper powder reduced in Step 3 from the graphite crucible. After vibration particle size screening, Cu powder meeting the required particle size requirements can be obtained. The sample diagram of the metallic Cu powder is as shown in Figure 5 shown.

[0053] Example 3

[0054] In the method for hydrogen metallurgy reduction of molybdenum oxide in this example, the device for hydrogen metallurgy reduction of metal oxides in Example 1 is adopted, and it includes the following steps:

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

[0056] Step 2. Horizontally place the lower end of the graphite crucible on the hollow support, evacuate the furnace chamber. When the vacuum gauge of the furnace body shows less than 800 Pa, then use argon to displace the air in the furnace chamber, and circulate the displacement 5 times;

[0057] Step 3. After the argon displacement in Step 2 is completed, introduce the reducing gas H2 into the graphite crucible through the hollow support at a flow rate of 60 ml / min. At the same time, start the heating system of the tube furnace at 10 °C / min, reach the required reduction temperature of 1000 °C, and keep it warm for 120 min to carry out the reduction reaction;

[0058] Step 4. Pour out and collect the metallic molybdenum powder reduced in Step 3 from the graphite crucible. After vibration particle size screening, Mo powder meeting the required particle size requirements can be obtained. The SEM diagram of the metallic Mo powder is as shown in Figure 6 shown.

[0059] Example 4

[0060] In the device and method for hydrogen metallurgy reduction of iron(III) oxide in this example, the device for hydrogen metallurgy reduction of metal oxides in Example 1 is adopted, and it includes the following steps:

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

[0062] Step 2. Horizontally place the lower end of the graphite crucible on the hollow support, evacuate the furnace chamber. When the vacuum gauge of the furnace body shows less than 800 Pa, then use argon to displace the air in the furnace chamber, and circulate the displacement 5 times;

[0063] Step 3: After the argon replacement in Step 2 is completed, introduce the reducing gas H2 into the graphite crucible through the hollow support column at a flow rate of 60 ml / min. At the same time, turn on the heating system of the tube furnace at a rate of 10 °C / min until the reduction temperature of 900 °C is reached, and keep the temperature for 90 min to carry out the reduction reaction;

[0064] Step 4: Pour out and collect the elemental Fe powder obtained by reduction in Step 3 from the graphite crucible. After vibrating particle size screening, Fe powder meeting the required particle size requirements can be obtained. The sample diagram of the metallic Fe powder is as 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, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions 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, the graphite crucible is a cylindrical structure with two ends open, 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; 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.

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 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.

4. The device for hydrogen metallurgical reduction of metal oxides according to claim 1, characterized in that: The diameter of the through hole is less than 10 mm.

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

6. 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.

7. 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 6 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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