Device and method for preparing spherical iron powder from ultra-pure iron concentrate by hydrogen-based flash reduction

Abstract

The application discloses a device for preparing spherical iron powder through hydrogen-based flash reduction of super-pure iron concentrate, which comprises a flash reduction assembly and a fluidized bed assembly. The flash reduction assembly comprises a flash reduction furnace, which has a first chamber and a first discharge port in communication with each other. The first chamber is provided with super-pure iron concentrate and H2-rich reducing gas, and the super-pure iron concentrate is subjected to hydrogen-based flash reduction in the first chamber to generate spherical iron powder. The fluidized bed assembly comprises a fluidized bed, which has a second chamber and a second discharge port in communication with each other. The second chamber is provided with reducing gas comprising CO and H2. The spherical iron powder in the first chamber can enter the second chamber through the first discharge port and is subjected to secondary fine reduction reaction with the reducing gas in the second chamber. The device for preparing spherical iron powder through hydrogen-based flash reduction of super-pure iron concentrate has simple structure, and the produced iron powder has less impurities and high purity. In addition, the device can effectively reduce the emission of CO2 and reduce the environmental load.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgical engineering, in particular, to a device and method for preparing spherical iron powder by hydrogen-based flash reduction of super-pure iron concentrate. BACKGROUND

[0002] Powder metallurgy is a technology that uses a mixture of metal and non-metal powders as raw materials to obtain various materials and products through pressing, sintering and subsequent processing. As a high-performance metal powder, spherical iron powder is mainly used in advanced technologies such as metal additive manufacturing and injection molding, especially in the field of additive manufacturing, which has great significance.

[0003] Currently, the production processes of spherical iron powder mainly include hydroxyl method and atomization method. The hydroxyl method is to react CO with iron at high pressure to obtain oil Fe(CO)5, which is then condensed and collected, and Fe(CO)5 is decomposed to obtain iron powder. The iron powder prepared by this method has good sphericity, close single particle size distribution, low porosity, high purity and other characteristics. However, since the hydroxyl metal gas is highly toxic, a complete closed production system is required, resulting in high production cost.

[0004] The atomization method is to generate high-pressure and high-speed fluid through an atomizing nozzle, which rapidly impacts the molten metal stream to crush the molten stream into fine droplets and rapidly condense to obtain fine metal powder. The commonly used atomizing medium is water or gas, which is called water atomization and gas atomization, respectively. Water atomization has high recovery rate and fast cooling speed, but the powder has high oxygen content and irregular shape, usually in the form of flakes. The powder prepared by gas atomization has small particle size, high sphericity and low oxygen content. The production of spherical powder by atomization method has the defect of high energy consumption, and the nozzle has high requirements.

[0005] Patent 201810309406.6 discloses a method for preparing micron-sized spherical iron powder. Methane is used as the main reducing agent, and the rapid reduction is carried out at a temperature of 1200-1600℃. After the reduction, carburization, melting and solidification processes in the reactor, spherical iron-carbon alloy powder is obtained.

[0006] However, the above-mentioned spherical iron powder preparation method has the disadvantages of complex production process, large equipment investment, high production cost, and high impurity content and low purity of the generated iron powder. SUMMARY

[0007] The present application aims to at least partially solve one of the technical problems in the related art. To this end, an embodiment of the present application proposes a device for preparing spherical iron powder by hydrogen-based flash reduction of super-pure iron concentrate, which has a simple structure and produces iron powder with less impurities and high purity, and can effectively reduce CO2 emissions and reduce environmental load.

[0008] The device for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate according to the embodiment of the application comprises:

[0009] a flash reduction assembly, wherein the flash reduction assembly comprises a flash reduction furnace, the flash reduction furnace has a first chamber, a first discharge port and a feeding port, the first chamber is in communication with the feeding port and the first discharge port, the first chamber is provided with ultra-pure iron concentrate and reducing gas and oxygen-enriched air, the reducing gas in the first chamber comprises H2, the ultra-pure iron concentrate is subjected to a hydrogen flash reduction reaction in the first chamber and generates pre-reduced spherical iron powder;

[0010] a fluidized bed assembly, wherein the fluidized bed assembly comprises a fluidized bed, the fluidized bed has a second chamber and a second discharge port, the second chamber is in communication with the second discharge port and the first discharge port, the second chamber is provided with reducing gas, the pre-reduced spherical iron powder generated in the first chamber can enter the second chamber through the first discharge port and is subjected to a secondary fine reduction reaction with the reducing gas in the second chamber to generate high-metalization-rate spherical iron powder, and the reducing gas in the second chamber comprises CO and H2.

[0011] In the device for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate according to the embodiment of the application, the ultra-pure iron concentrate is first subjected to a reduction reaction with reducing gas in the first chamber and generates pre-reduced spherical iron powder, the reducing gas in the first chamber mainly comprises H2, which improves the purity of the produced spherical iron powder, the pre-reduced spherical iron powder enters the second chamber through the first discharge port, is subjected to a secondary fine reduction reaction with CO and H2 in the second chamber and generates high-metalization-rate spherical iron powder, and the metalization rate of the ultra-pure iron concentrate is improved. Thus, the device for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate according to the embodiment of the application has a simple structure, produces iron powder with less impurities and high purity, and can effectively reduce the emission of CO2 and reduce the environmental load.

[0012] In some embodiments, the first chamber comprises, from top to bottom, a preheating section, a reduction section and a cooling section in sequence, the ultra-pure iron concentrate sequentially passes through the preheating section, the reduction section and the cooling section, the temperature of the reduction section is 1380-1600℃, and the temperature of the cooling section is less than 1000℃.

[0013] In some embodiments, the flash reduction furnace further has a first gas outlet, the first gas outlet is in communication with the first chamber, and the flash reduction assembly further comprises:

[0014] a first discharger, the first discharger is in communication with the first discharge port and the second chamber, so that part of the coarse particle pre-reduced spherical iron powder generated in the first chamber can enter the second chamber through the first discharger;

[0015] a second outlet communicating with the first outlet and the second chamber, so that the fine particle pre-reduced spherical iron powder produced in the first chamber can enter the second chamber through the second outlet.

[0016] In some embodiments, the first outlet is located at the bottom of the flash reduction furnace, and the first outlet is located above the first outlet.

[0017] In some embodiments, the flash reduction assembly further comprises a first separator located between the second outlet and the flash reduction furnace and communicating with the second outlet and the first outlet, the first separator being used to separate the fine particle pre-reduced spherical iron powder entrained in the gas discharged from the first outlet.

[0018] In some embodiments, the flash reduction assembly further comprises a purifier and a composition adjuster, the purifier communicating with the first separator and the composition adjuster, the purifier being used to purify the gas flowing from the first separator into the composition adjuster,

[0019] The composition adjuster communicates with the fluidized bed, and the composition adjuster is used to adjust the proportion of CO and H2 in the gas flowing from the purifier into the composition adjuster and to introduce CO and H2 into the second chamber to meet the production needs of the fluidized bed.

[0020] In some embodiments, the fluidized bed also has a second outlet communicating with the second chamber, the second outlet is located at the bottom of the fluidized bed, and the second outlet is located at the top of the fluidized bed, the fluidized bed assembly comprising:

[0021] A third outlet communicating with the second chamber through the second outlet, the pre-reduced spherical iron powder in the second chamber is subjected to a secondary reduction reaction with the reducing gas in the second chamber to produce high-metalization-rate spherical iron powder, and part of the coarse particle high-metalization-rate spherical iron powder in the second chamber is discharged into the third outlet through the second outlet for storage;

[0022] A fourth outlet communicating with the second outlet and the second chamber, the fine particle high-metalization-rate spherical iron powder entrained in the gas discharged from the second outlet enters the fourth outlet.

[0023] In some embodiments, the fluidized bed assembly further comprises a second separator, which is located between and in communication with the fourth discharge device and the second chamber, and is used to separate fine-particle high-metalization spherical iron powder entrained in gas in the second chamber.

[0024] In some embodiments, the fluidized bed assembly further comprises a discharge bin, which is in communication with the third discharge device and the fourth discharge device, and is used to store high-metalization spherical iron powder in the third discharge device and the fourth discharge device.

[0025] In some embodiments, the device for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate further comprises a pretreatment assembly, which comprises, in sequence, a drying member, a screening member, a lifting member, and a feeding member, the drying member is used to dry the ultra-pure iron concentrate, the screening member is used to screen the ultra-pure iron concentrate, the lifting member is used to lift the ultra-pure iron concentrate from the screening member to the feeding member, the feeding member is in communication with the feeding port, and the feeding member is used to pass the ultra-pure iron concentrate into the first chamber.

[0026] The method for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate according to the embodiments of the present application comprises:

[0027] The ultra-pure iron concentrate is screened to obtain ultra-pure iron concentrate with a particle size of less than 100 μm, and the mass percentage of TFe in the ultra-pure iron concentrate is ≥ 70%;

[0028] The ultra-pure iron concentrate is sprayed into the first chamber of the flash reduction furnace through the feeding port, reducing gas and oxygen-rich air are injected into the first chamber, the ultra-pure iron concentrate is rapidly reduced in the reduction section to generate spherical molten droplets, and the spherical molten droplets rapidly solidify to form pre-reduced spherical iron powder when passing through the cooling zone,

[0029] The reduction temperature of the ultra-pure iron concentrate in the reduction section is 1380-1600℃, and the reduction time is 1-10 s,

[0030] The reducing gas in the first chamber comprises H2, and the content of H2 is greater than 60%, and the metallization rate of the ultra-pure iron concentrate is > 85%;

[0031] The pre-reduced spherical iron powder in the first chamber is discharged into the second chamber of the fluidized bed, reducing gas is injected into the second chamber, and the pre-reduced spherical iron powder is subjected to secondary fine reduction in the second chamber to produce high-metalization spherical iron powder,

[0032] The reduction temperature in the second chamber is 600-900℃, and the reaction time is 10-60 min,

[0033] The reducing gas in the second chamber comprises CO+H2, and the content of CO+H2 is greater than 75%, and the metallization rate of the super-pure iron concentrate is greater than 99%.

[0034] The method for preparing spherical iron powder by hydrogen-based flash reduction of super-pure iron concentrate according to the embodiment of the application has the H2 content in the reducing gas in the first chamber greater than 60%, which reduces the possibility of carburization of the iron powder, improves the purity of the produced spherical iron powder, and further improves the purity of the produced spherical iron powder and the metallization rate of the super-pure iron concentrate through the secondary reduction reaction of the pre-reduced spherical iron powder with the main reducing gas CO+H2 in the second chamber, reduces the emission of CO2, reduces the environmental load, and the production process of the spherical iron powder is simple and saves investment cost. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a schematic diagram of the device for preparing spherical iron powder by hydrogen-based flash reduction of super-pure iron concentrate according to the embodiment of the application.

[0036] The figure mark: 1, flash reduction assembly; 11, flash reduction furnace; 111, first chamber; 112, first discharge port; 113, first gas outlet; 114, feeding port; 12, first discharger; 13, second discharger; 14, first separator; 15, purifier; 16, component adjuster; 2, fluidized bed assembly; 21, fluidized bed; 211, second chamber; 212, second discharge port; 213, second gas outlet; 22, third discharger; 23, fourth discharger; 24, second separator; 25, discharge bin; 3, pretreatment assembly; 31, drying piece; 32, screening piece; 33, lifting piece; 34, feeding piece. DETAILED DESCRIPTION

[0037] The embodiments of the application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.

[0038] As shown in the figure, Figure 1 The device for preparing spherical iron powder by hydrogen-based flash reduction of super-pure iron concentrate according to the embodiment of the application comprises a flash reduction assembly 1 and a fluidized bed assembly 2.

[0039] The flash reduction assembly 1 comprises a flash reduction furnace 11, and the flash reduction furnace 11 has a first chamber 111, a first discharge port 112, and a feeding port 114. The first chamber 111 is in communication with the feeding port 114 and the first discharge port 112. The first chamber 111 has super-pure iron concentrate and reducing gas and oxygen-enriched air therein. The reducing gas in the first chamber 111 comprises H2. The super-pure iron concentrate is subjected to hydrogen flash reduction reaction in the first chamber 111 and generates pre-reduced spherical iron powder.

[0040] The fluidized bed assembly 2 comprises a fluidized bed 21 having a second chamber 211 and a second discharge port 212, the second chamber 211 being in communication with the second discharge port 212 and the first discharge port 112, and having a reducing gas in the second chamber 211, the pre-reduced spherical iron powder generated in the first chamber 111 can enter the second chamber 211 through the first discharge port 112 and perform a secondary fine reduction reaction with the reducing gas in the second chamber 211 to generate high-metalization-rate spherical iron powder, and the reducing gas in the second chamber 211 comprises CO and H2.

[0041] The device for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate according to the embodiment of the present application can improve the purity of the produced spherical iron powder, and the metalization rate of the ultra-pure iron concentrate, and can effectively reduce the emission of CO2 and the environmental load. In addition, the device for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate according to the embodiment of the present application has a simple structure and saves cost.

[0042] In some embodiments, the feeding port 114 of the flash reduction furnace 11 is located at the top of the flash reduction furnace 11 and is in communication with the first chamber 111, and the ultra-pure iron concentrate and the reducing gas are sprayed into the first chamber 111 through the feeding port 114.

[0043] Specifically, the reducing gas comprises one or more of coke oven gas, converter gas, blast furnace gas, natural gas, liquefied gas, shale gas, biomass gas, and hydrogen gas. The content of hydrogen gas is greater than 60%. The oxygen content in the oxygen-enriched air is 50% to 99.5%.

[0044] Specifically, the first chamber 111 of the flash reduction furnace 11 is sequentially divided into a preheating section, a reduction section, and a cooling section from top to bottom. The reaction temperature of the reduction section is 1380℃ to 1600℃, and the temperature of the cooling section is less than 1000℃. In the process of falling into the first chamber 111, the ultra-pure iron concentrate first passes through the reduction section and performs a flash reduction reaction in the reduction section, and then passes through the cooling section to rapidly reduce the temperature to below 1000℃, thereby obtaining pre-reduced spherical iron powder with a metalization rate greater than 85%.

[0045] Specifically, the temperature of the reducing gas in the second chamber 211 is 600℃ to 900℃, and the pre-reduced spherical iron powder and the reducing gas entering the second chamber 211 from the first chamber 111 perform a secondary fine reduction in the second chamber 211, thereby obtaining high-metalization-rate spherical iron powder with a metalization rate greater than 99%.

[0046] Specifically, the mass percentage of TFe in the ultra-pure iron concentrate is ≥70%.

[0047] In some embodiments, the flash reduction furnace 11 further has a first gas outlet 113. The first gas outlet 113 is in communication with the first chamber 111, and the first gas outlet 113 is located above the first discharge outlet 112.

[0048] The flash reduction assembly 1 further comprises a first discharge device 12 and a second discharge device 13. The first discharge device 12 is in communication with the first discharge outlet 112 and the second chamber 211, so that part of the coarse particle pre-reduced spherical iron powder generated in the first chamber 111 can enter the second chamber 211 through the first discharge device 12. The second discharge device 13 is in communication with the second discharge outlet 113 and the second chamber 211, so that part of the fine particle pre-reduced spherical iron powder generated in the first chamber 111 can enter the second chamber 211 through the second discharge device 13.

[0049] Specifically, the mass of the fine particle pre-reduced spherical iron powder is less than that of the coarse particle pre-reduced spherical iron powder, and the first chamber 111 further has gas, so that the tail gas in the first chamber 111 carries the fine particle pre-reduced spherical iron powder from the second discharge outlet 113 into the second discharge device 13 for storage.

[0050] In some embodiments, the flash reduction assembly 1 further comprises a first separator 14, which is located between the second discharge device 13 and the flash reduction furnace 11 and is in communication with the second discharge device 13 and the first gas outlet 113. The first separator 14 is used to separate the fine particle pre-reduced spherical iron powder entrained in the tail gas discharged from the first gas outlet 113.

[0051] Specifically, the gas in the first chamber 111 carries the fine particle pre-reduced spherical iron powder in the first chamber 111 from the first gas outlet 113 into the first separator 14, and the first separator 14 separates the gas and the fine particle pre-reduced spherical iron powder, and discharges the fine particle pre-reduced spherical iron powder into the second discharge device 13.

[0052] In some embodiments, the flash reduction assembly 1 further comprises a purifier 15 and a composition adjuster 16. The purifier 15 is in communication with the first separator 14 and the composition adjuster 16, and the purifier 15 is used to purify the gas flowing from the first separator 14 into the composition adjuster 16.

[0053] Specifically, the purifier 15 is connected to the first separator 14 to purify the gas entering the purifier 15 from the first separator 14, so as to further separate the gas and the fine particle pre-reduced spherical iron powder, thereby further reducing the fine particle iron powder carried in the gas entering the composition adjuster 16.

[0054] The composition adjuster 16 is in communication with the fluidized bed 21, and is configured to adjust the proportions of CO and H2 in the gas flowing from the purifier 15 into the composition adjuster 16 and to introduce the CO and H2 into the second chamber 211 to meet the production needs of the fluidized bed 21.

[0055] Specifically, the composition adjuster 16 is configured to adjust the contents of CO and H2 in the gas inside the composition adjuster 16 so that the contents of CO+H2 are greater than 75%, and to introduce the CO and H2 into the second chamber 211 to perform a secondary fine reduction reaction with the pre-reduced spherical iron powder in the second chamber 211 to generate high metallization rate spherical iron powder, so as to recycle the tail gas in the first chamber 111.

[0056] In some embodiments, the fluidized bed 21 includes a second discharge port 212 at the bottom of the fluidized bed 21 and a second gas outlet 213 at the top of the fluidized bed 21.

[0057] The fluidized bed assembly 2 includes a third discharge device 22 and a fourth discharge device 23. The third discharge device 22 is in communication with the second chamber 211 through the second discharge port 212, and the pre-reduced spherical iron powder in the second chamber 211 performs a secondary fine reduction reaction with the reducing gas in the second chamber 211 to generate high metallization rate spherical iron powder, and part of the coarse particle high metallization rate spherical iron powder in the second chamber 211 is discharged into the third discharge device 22 through the second discharge port 212 for storage.

[0058] The fourth discharge device 23 is in communication with the second chamber 211 through the second gas outlet 213, and the fine particle high metallization rate spherical iron powder generated in the second chamber 211 enters the fourth discharge device 23 through the second gas outlet 213 for storage. Specifically, the mass of the fine particle high metallization rate spherical iron powder is smaller than that of the coarse particle high metallization rate spherical iron powder, and the second chamber 211 has gas therein, and the tail gas in the second chamber 211 carries the fine particle spherical iron powder from the bottom to the top of the second chamber 211 and enters the fourth discharge device 23 through the second gas outlet 213 for storage.

[0059] In some embodiments, the fluidized bed assembly 2 further includes a second separator 24 between the fourth discharge device 23 and the fluidized bed 21 and in communication with the fourth discharge device 23 and the second chamber 211, and the second separator 24 is configured to separate the fine particle high metallization rate spherical iron powder entrained in the tail gas in the second chamber 211.

[0060] Specifically, the tail gas in the second chamber 211 carries the fine high metallization rate spherical iron powder in the second chamber 211 into the second separator 24, the second separator 24 separates the gas and the fine high metallization rate spherical iron powder, and discharges the fine high metallization rate spherical iron powder into the fourth discharge device 23.

[0061] In some embodiments, the fluidized bed assembly 2 further comprises a discharge bin 25, the discharge bin 25 being in communication with the third discharge device 22 and the fourth discharge device 23, and the discharge bin 25 being used for storing the high metallization rate spherical iron powder in the third discharge device 22 and the fourth discharge device 23.

[0062] In some embodiments, the device for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate further comprises a pretreatment assembly 3, the pretreatment assembly 3 comprising a drying member 31, a screening member 32, a lifting member 33 and a feeding member 34 connected in sequence, the drying member 31 being used for drying the ultra-pure iron concentrate, the screening member 32 being used for screening the ultra-pure iron concentrate, the lifting member 33 being used for lifting the ultra-pure iron concentrate from the screening member 32 to the feeding member 34, the feeding member 34 being in communication with the first chamber 111, and the feeding member 34 being used for feeding the ultra-pure iron concentrate into the first chamber 111.

[0063] Specifically, the drying member 31 dries the ultra-pure iron concentrate to a moisture mass fraction of less than 1% in the ore powder, and then feeds the ultra-pure iron concentrate into the screening member 32, and the screening member 32 screens the ultra-pure iron concentrate to obtain the ore powder with a particle size of 20-40 μm.

[0064] In some embodiments, a method for preparing spherical iron powder by hydrogen-based flash reduction of ultra-pure iron concentrate comprises:

[0065] Firstly, the ultra-pure iron concentrate is pretreated.

[0066] Specifically, the ultra-pure iron concentrate is dried by the drying member 31 until the moisture mass fraction in the ultra-pure iron concentrate is less than 1%. Then, the dried ultra-pure iron concentrate is fed into the screening member 32, and the screening member 32 screens the ultra-pure iron concentrate to obtain the ultra-pure iron concentrate with a particle size of less than 100 μm. The ultra-pure iron concentrate is lifted by the lifting member 33 to the feeding member 34 for storage, and the feeding member 34 is in communication with the feeding port 114, so that the ore powder can be sprayed into the first chamber 111 through the feeding port 114. The mass percentage of TFe in the ultra-pure iron concentrate is ≥70%.

[0067] Secondly, the ultra-pure iron concentrate is subjected to a rapid reduction reaction.

[0068] Specifically, the super-pure iron concentrate is injected into the first chamber 111 of the flash reduction furnace 11 through the feeding port 114, and the reducing gas and the oxygen-rich air are injected into the first chamber 111, the super-pure iron concentrate is preheated in the preheating section in the first chamber 111, then is flash-reduced in the reduction section to generate spherical molten droplets, and then the spherical molten droplets are rapidly cooled and solidified to form pre-reduced spherical iron powder when descending through the cooling zone.

[0069] After the rapid reduction reaction of the super-pure iron concentrate is completed, the coarse-grained pre-reduced spherical iron powder generated in the first chamber 111 is stored in the first discharger 12 through the first discharging port 112, and the reducing tail gas in the first chamber 111 enters the first separator 14 through the first gas outlet 113 to separate the fine-grained pre-reduced spherical iron powder carried in the tail gas into the second discharger 13.

[0070] In the above process, the reduction temperature of the super-pure iron concentrate in the reduction section is 1380-1600°C, the reduction time is 1-10s, and the cooling temperature of the spherical molten droplets in the cooling zone is less than 1000°C.

[0071] In the above process, the reducing gas in the first chamber 111 includes H2, and the content of H2 is greater than 60%, which can effectively reduce the possibility of carburization in the reduction process of the super-pure iron concentrate and improve the purity of the generated spherical iron powder. The metallization rate of the super-pure iron concentrate is greater than 85%.

[0072] Specifically, in the flash reduction process, the reduction time of the super-pure iron concentrate powder can be adjusted by adjusting the gas velocity of the reducing gas, the metallization rate of the reduced super-pure iron concentrate can be adjusted by adjusting the reduction temperature and the reduction atmosphere, and in order to maintain the reduction temperature, a proper amount of preheated oxygen-rich air can be introduced into the first chamber 111 to make the combustible gas burn and release heat.

[0073] Thirdly, the pre-reduced spherical iron powder is subjected to a secondary fine reduction reaction.

[0074] The pre-reduced spherical iron powder in the first discharger 12 and the second discharger 13 is discharged into the second chamber 211 of the fluidized bed 21, and the reducing gas is injected into the second chamber 211, so that the pre-reduced spherical iron powder is subjected to a secondary fine reduction in the second chamber 211.

[0075] After the secondary fine reduction reaction is completed, the coarse-grained high-metallization-rate spherical iron powder generated in the second chamber 211 is stored in the third discharger 22 through the second discharging port 212, the reducing tail gas in the second chamber 211 enters the second separator 24 through the second gas outlet 213 to separate the fine-grained high-metallization-rate spherical iron powder carried in the tail gas into the fourth discharger 23 for storage, and then the coarse-grained high-metallization-rate spherical iron powder and the fine-grained high-metallization-rate spherical powder are discharged into the discharging bin 25.

[0076] The reduction temperature in the second chamber 211 is 600-900 DEG C, and the reaction time is 10-60 min.

[0077] The reduction gas in the second chamber 211 includes CO+H2, and the content of CO+H2 is greater than 75%, which can further improve the purity of the spherical iron powder, improve the metallization rate of the ultra-pure iron concentrate, reduce the emission of CO2, and reduce the environmental load. The metallization rate of the ultra-pure iron concentrate is greater than 99%.

[0078] Specifically, the gas in the second chamber 211 can be purified and adjusted and then introduced into the second chamber 211 as a reduction gas, so as to realize the recycling of the tail gas.

[0079] The principle of the method for preparing the spherical iron powder by the hydrogen-based flash reduction of the ultra-pure iron concentrate according to the embodiment of the application is as follows: since the particle size of the ultra-pure iron concentrate is less than 100 μm, and the ultra-pure iron concentrate is in a suspended state in the first chamber 111 during the rapid reduction process, the heat and mass transfer processes between the ultra-pure iron concentrate and the gas are strengthened, so that the reduction reaction can be completed within 1-10 s. The flash reduction temperature in the first chamber 111 ranges from 1380 DEG C to 1600 DEG C, so that the intermediate product FeO generated in the rapid reduction process is melted and naturally shrunk into a spherical shape in the temperature range, so as to facilitate the further reduction to obtain the spherical metallic iron powder. The pre-reduced spherical iron powder in the first chamber 111 is sent into the second chamber 211, and high-temperature reduction gas is introduced into the second chamber 211 to perform secondary fine reduction on the pre-reduced spherical iron powder, so as to obtain the high-metallization-rate spherical iron powder with a metallization rate greater than 99%.

[0080] Therefore, the process for producing the spherical iron powder by using the method for preparing the spherical iron powder by the hydrogen-based flash reduction of the ultra-pure iron concentrate according to the embodiment of the application is simple, and the cost is saved.

[0081] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0082] In addition, the terms "first", "second", etc. are used only for the purpose of description and do not imply or imply relative importance or imply the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0083] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or in communication with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication or interaction of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0084] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0085] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present specification and the features of different embodiments or examples without contradiction.

[0086] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and cannot be construed as limiting the present application, and the changes, modifications, replacements and variations of the above embodiments made by those skilled in the art are within the scope of the present application.

Claims

1. An apparatus for the production of spherical iron powder by ultra-pure iron concentrate hydrogen-based flash reduction, characterized by, Comprise: flash reduction assembly (1), the flash reduction assembly (1) includes flash reduction furnace (11), the flash reduction furnace (11) has first chamber (111), first discharge port (112) and feed port (114), the first chamber (111) and the feed port (114) and the first discharge port (112) are interconnected, the first chamber (111) has ultra-pure iron concentrate and reducing gas and oxygen-enriched air, the reducing gas in the first chamber (111) includes H2, the ultra-pure iron concentrate carries out hydrogen flash reduction reaction in the first chamber (111) and generates pre-reduced spherical iron powder; Fluidized bed assembly (2), the fluidized bed assembly (2) includes fluidized bed (21), the fluidized bed (21) has second chamber (211) and second discharge port (212), the second chamber (211) and the second discharge port (212) and the first discharge port (112) are communicated, the second chamber (211) has reducing gas, the pre-reduced spherical iron powder generated in the first chamber (111) can enter the second chamber (211) through the first discharge port (112) and carry out secondary fine reduction reaction with the reducing gas in the second chamber (211), generate high metallization rate spherical iron powder, the reducing gas in the second chamber (211) includes CO and H2; The fluidized bed (21) also has second gas outlet (213), the second gas outlet (213) and the second chamber (211) are communicated, the second discharge port (212) is located at the bottom of the fluidized bed (21), and the second gas outlet (213) is located at the top of the fluidized bed (21), and the fluidized bed assembly (2) comprises: Third discharge device (22), the third discharge device (22) is communicated with the second chamber (211) through the second discharge port (212), the pre-reduced spherical iron powder in the second chamber (211) carries out secondary fine reduction reaction with the reducing gas in the second chamber (211) and generates high metallization rate spherical iron powder, and part of the coarse particle high metallization rate spherical iron powder in the second chamber (211) is discharged into the third discharge device (22) through the second discharge port (212) for storage; Fourth discharge device (23), the fourth discharge device (23) is communicated through the second gas outlet (213) and the second chamber (211), and the second gas outlet (213) discharges the fine particle high metallization rate spherical iron powder mixed in the gas into the fourth discharge device (23); The first chamber (111) includes preheating section, reduction section and cooling section arranged in sequence from top to bottom, the ultra-pure iron concentrate sequentially passes through the preheating section, the reduction section and the cooling section, the temperature of the reduction section is 1380~1600 ℃, and the temperature of the cooling section is less than 1000 ℃.

2. The apparatus for the production of spherical iron powder by ultra pure iron concentrate hydrogen based flash reduction as claimed in claim 1 wherein, The flash reduction furnace (11) also has a first gas outlet (113), and the first gas outlet (113) is communicated with the first chamber (111), and the flash reduction assembly (1) further comprises: A first discharger (12) is connected with the first discharging port (112) and the second chamber (211) to allow the part of the coarse particle pre-reduced spherical iron powder generated in the first chamber (111) to enter the second chamber (211) through the first discharger (12); A second discharger (13) is connected with the first gas outlet (113) and the second chamber (211) to allow the part of the fine particle pre-reduced spherical iron powder generated in the first chamber (111) to enter the second chamber (211) through the second discharger (13).

3. The apparatus for the production of spherical iron powder by ultra pure iron concentrate hydrogen based flash reduction as claimed in claim 2 wherein, The first discharging port (112) is located at the bottom of the flash reduction furnace (11), and the first gas outlet (113) is located above the first discharging port (112).

4. The apparatus for the production of spherical iron powder by ultra pure iron concentrate hydrogen based flash reduction as claimed in claim 3 wherein, The flash reduction assembly (1) further comprises a first separator (14) located between the second discharger (13) and the flash reduction furnace (11) and connected with the second discharger (13) and the first gas outlet (113), and the first separator (14) is used for separating the fine particle pre-reduced spherical iron powder mixed in the gas discharged from the first gas outlet (113).

5. The apparatus for the production of spherical iron powder by ultra pure iron concentrate hydrogen based flash reduction as claimed in claim 4 wherein, The flash reduction assembly (1) further comprises a purifier (15) and a composition adjuster (16), the purifier (15) is connected with the first separator (14) and the composition adjuster (16), and the purifier (15) is used for purifying the gas flowing from the first separator (14) to the composition adjuster (16), The composition adjuster (16) is connected with the fluidized bed (21), and the composition adjuster (16) is used for adjusting the proportion of CO and H2 in the gas flowing from the purifier (15) to the composition adjuster (16) and introducing CO and H2 into the second chamber (211) to meet the production needs of the fluidized bed (21).

6. The apparatus for the production of spherical iron powder by ultra pure iron concentrate hydrogen based flash reduction as claimed in claim 1 wherein, The fluidized bed assembly (2) further comprises a second separator (24) located between the fourth discharger (23) and the fluidized bed (21) and connected with the fourth discharger (23) and the second chamber (211), and the second separator (24) is used for separating the fine particle high metallization rate spherical iron powder mixed in the gas in the second chamber (211).

7. The apparatus for the production of spherical iron powder by ultra pure iron concentrate hydrogen based flash reduction as claimed in claim 6 wherein, The fluidized bed assembly (2) further comprises a discharging bin (25) connected with the third discharger (22) and the fourth discharger (23), and the discharging bin (25) is used for storing the high metallization rate spherical iron powder in the third discharger (22) and the fourth discharger (23).

8. The apparatus for the production of spherical iron powder by ultra pure iron concentrate hydrogen based flash reduction as claimed in claim 1 wherein, The pre-treatment assembly (3) comprises a drying member (31), a screening member (32), a lifting member (33) and a feeding member (34) connected in sequence, the drying member (31) is used for drying the ultra-pure iron concentrate, the screening member (32) is used for screening the ultra-pure iron concentrate, the lifting member (33) is used for lifting the ultra-pure iron concentrate from the screening member (32) to the feeding member (34), the feeding member (34) is communicated with the feeding port (114), and the feeding member (34) is used for feeding the ultra-pure iron concentrate into the first chamber (111).

9. A process for the production of spherical iron powder by ultra-pure iron concentrate hydrogen-based flash reduction, characterized by, The method comprises the steps of: Screening the ultra-pure iron concentrate to obtain the ultra-pure iron concentrate with a particle size less than 100 μm, and the mass percentage of TFe in the ultra-pure iron concentrate is greater than or equal to 70%; The ultra-pure iron concentrate is sprayed into the first chamber (111) of the flash reduction furnace (11) through the feeding port (114), the reducing gas and the oxygen-rich air are injected into the first chamber (111), the ultra-pure iron concentrate is rapidly reduced in the reduction section to generate spherical molten droplets, and the spherical molten droplets are rapidly cooled and solidified to form pre-reduced spherical iron powder when passing through the cooling zone, The reduction temperature of the ultra-pure iron concentrate in the reduction section is 1380-1600 °C, and the reduction time is 1-10 s, The reducing gas in the first chamber (111) comprises H2, and the content of H2 is greater than 60%, and the metallization rate of the ultra-pure iron concentrate is greater than 85%; The pre-reduced spherical iron powder in the first chamber (111) is discharged into the second chamber (211) of the fluidized bed (21), and the reducing gas is injected into the second chamber (211), the pre-reduced spherical iron powder is subjected to secondary fine reduction in the second chamber (211) to produce high-metallization-rate spherical iron powder, The reduction temperature in the second chamber (211) is 600-900 °C, and the reaction time is 10-60 min, The reducing gas in the second chamber (211) comprises CO+H2, and the content of CO+H2 is greater than 75%, and the metallization rate of the ultra-pure iron concentrate is greater than 99%.

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