Method for preparing pellets from rich ore powder

Abstract

The invention provides a method for preparing pellets from rich ore powder. The method comprises the steps that rich ore powder is subjected to at least four-stage double-roller crushing and at least two-stage four-roller crushing in sequence, and rich ore pelletizing powder is prepared; wherein the at least four stages of roller crushing comprise at least two stages of hard alloy column nail roller-to-roller crushing performed firstly and at least two stages of smooth roller-to-roller crushing performed later; a smooth roll adopted for smooth roll pair crushing is hollow and comprises a circular truncated cone section with the side surface serving as a smooth roll grinding face and a cylindrical section connected with one end of the bottom face, with the large area, of the circular truncated cone section, and circular holes consistent with the crushing size fraction are formed in the side surface of the circular truncated cone section. The side surface of the cylindrical section is provided with a circular hole with the diameter larger than that of the circular hole in the side surface of the circular truncated cone section. And the rich ore pelletizing powder is sequentially subjected to pelletizing material preparation, pelletizing, screening, material distribution and roasting, and the pellets are obtained. According to the method, the large-granularity rich ore powder can be ground to the qualified pelletizing granularity, and then the problem that qualified pellets are difficult to produce from the large-granularity rich ore powder is solved.

Description

Technical Field

[0001] The invention relates to the technical field of pellet preparation, and in particular to a method for preparing pellets by using rich ore powder. Background Art

[0002] Pellet ore has become an indispensable high-quality charge for blast furnace ironmaking due to its uniform particle size, high iron grade, high mechanical strength, and good metallurgical properties. Pellet production has high requirements for iron concentrate raw materials, usually requiring them to have suitable particle size composition and specific surface area, low crystal water mass fraction, and reasonable chemical composition. At present, the main raw material for producing pellets is magnetite concentrate. With the rapid development of the steel industry, high-quality and stable magnetite concentrate resources are becoming increasingly scarce. Therefore, the development of a technical solution for preparing pellets using rich ore powder can reduce the ore blending cost of pellet preparation and broaden the source of iron concentrate for pellet preparation.

[0003] In the current research on the use of rich ore powder to prepare pellets, the research focus is mostly on the selection, proportioning and choice of binder of rich ore powder, and there is a lack of research and improvement on the process flow of preparing pellets with rich ore powder. Such research lacks integrity and systematicness and cannot fundamentally solve the problem that it is difficult to produce qualified pellets with large-particle rich ore powder.

[0004] The current process of preparing pellets from rich ore powder usually uses a dry ball mill or a high-pressure roller mill to simply grind the rich ore powder, and then uses the ground rich ore powder to produce pellets. Using a dry ball mill or a high-pressure roller mill to simply grind the rich ore powder can only partially solve the problem of small specific surface area and unqualified particle size of the material. At present, there is still a lack of a method that can fundamentally solve the problem that large-sized rich ore powder is difficult to grind to a qualified pelletizing particle size.

[0005] In summary, there is still a need to study new technical solutions for preparing pellets from rich ore powder, which can solve the problem that large-particle rich ore powder is difficult to grind to a qualified pelletizing size, and can solve the problem that large-particle rich ore powder is difficult to produce qualified pellets. Summary of the invention

[0006] The purpose of the present invention is to provide a new technical solution for preparing pellets from rich ore powder, so as to grind large-particle rich ore powder to a qualified pelletizing particle size, thereby solving the problem that large-particle rich ore powder is difficult to produce qualified pellets.

[0007] In order to achieve the above object, the present invention provides a method for preparing pellets using rich ore powder, the method comprising:

[0008] The rich ore powder is subjected to at least four-stage double-roller crushing and at least two-stage four-roller crushing in sequence to prepare rich ore pelletizing powder; wherein the at least four-stage double-roller crushing includes at least two stages of carbide column nail roller double-roller crushing performed first and at least two stages of smooth roller double-roller crushing performed later; the smooth roller used in the smooth roller double-roller crushing is hollow and includes a truncated cone section and a cylindrical section, the cylindrical section is connected to one end of the bottom surface with a large area of ​​the truncated cone section, the side surface of the truncated cone section is used as the grinding surface of the smooth roller, the side surface of the truncated cone section is provided with circular holes consistent with the crushing particle size, and the side surface of the cylindrical section is provided with circular holes with a diameter larger than the diameter of the circular holes on the side surface of the truncated cone section, the smooth roller can realize that the materials crushed to the corresponding particle size fall into the inner cavity of the truncated cone section of the smooth roller through the circular holes on the side surface of the truncated cone section, and then roll down to the inner cavity of the cylindrical section of the smooth roller, and then fall out of the smooth roller through the circular holes on the side surface of the cylindrical section of the smooth roller;

[0009] The rich ore pelletizing powder is sequentially subjected to pelletizing material preparation, pelletizing, screening, distribution and roasting to obtain the pelletized ore.

[0010] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the iron-rich powder includes at least one of hematite powder and magnetite powder.

[0011] According to a preferred embodiment of the method for preparing pellets using rich ore powder, the total iron content (TFe) of the iron-rich powder is not less than 66%.

[0012] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the particle size of the iron-rich powder does not exceed 8 mm.

[0013] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the diameter of the circular holes on the side surface of the cylindrical segment is more than twice the diameter of the circular holes on the side surface of the truncated cone segment.

[0014] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the at least four-stage roller crushing is a four-stage roller crushing, including two-stage carbide spike roller crushing performed first and two-stage smooth roller crushing performed later; the four-stage roller crushing is used to crush the material to a diameter below the A particle size, a diameter below the B particle size, a diameter below the C particle size, and a diameter below the D particle size in sequence; the A particle size is 4-40 mm, the B particle size is 2-4 mm, the C particle size is 1-2 mm, and the D particle size is 0.5-1 mm;

[0015] Furthermore, the diameter of the circular holes on the cylindrical section side surface of the smooth roller used in the first-stage smooth roller-to-roller crushing is 2C particle size, and the diameter of the circular holes on the truncated cone section side surface is C particle size, and the diameter of the circular holes on the cylindrical section side surface of the smooth roller used in the next-stage smooth roller-to-roller crushing is 2D particle size, and the diameter of the circular holes on the truncated cone section side surface is D particle size;

[0016] Furthermore, the at least two-stage four-roller crushing is a two-stage four-roller crushing; the two-stage four-roller crushing can successively crush the material to below the diameter E particle size and below the diameter F particle size; the E particle size is 0.1-0.5mm, and the F particle size is 0.074-0.1mm.

[0017] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the two smooth rollers used in the smooth roller-to-roller crushing are arranged on the same horizontal plane, the two smooth rollers have the same truncated cone segment structure, and one end of the bottom surface of the large truncated cone segment of each smooth roller is flush with one end of the bottom surface of the small truncated cone segment of the other smooth roller, and there is no gap between the grinding surfaces of the two smooth rollers;

[0018] This preferred technical solution is more conducive to the concentration of the material flow, while increasing the crushing time, providing tangential force while providing lateral crushing force, thereby enhancing the crushing effect, and does not set a gap between the two rollers to ensure the crushing quality.

[0019] According to a preferred embodiment of the method for preparing pellets using rich ore powder, the mass content of particles with a particle size of no more than 0.074 mm in the rich ore powder is not less than 85%, based on the total mass of the rich ore powder as 100%.

[0020] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the matrix material of the cemented carbide spike roller is 42CrMo or 40Cr.

[0021] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the matrix material of the smooth roller is 42CrMo or 40Cr.

[0022] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, each pair of roller crushers and each level of four-roller crushers are powered by a motor capable of providing a torque of more than 190 N / m in combination with a reducer;

[0023] Furthermore, the reducer adopts a DCY500-50 reducer;

[0024] Furthermore, the motor adopts a Y3553-4 motor.

[0025] According to a preferred embodiment of the method for preparing pelletized ore using rich ore powder, the preparation of pelletizing material includes:

[0026] Use rich ore pelletizing powder and solid binder, and optionally dust removal ash for batching;

[0027] Mixing the batched material with a liquid binder to obtain a mixture;

[0028] Add water to the mixture to obtain pelletizing material;

[0029] Furthermore, the solid binder includes at least one of bentonite and starch; the ratio of bentonite and starch can be adjusted according to the actual requirements of the raw ball index;

[0030] Furthermore, based on the mass of the pelletizing material being 100%, the moisture content of the pelletizing material is 8-12%;

[0031] Further, the pelletizing material preparation includes:

[0032] The prepared rich ore pelletizing powder is transported to the top of the batching room by a belt conveyor, and unloaded into the rich ore pelletizing powder silo; a disc feeder with variable frequency speed regulation and an electronic belt scale are provided under the rich ore pelletizing powder silo, a pressure-type silo top bag dust collector is provided on the top of the rich ore pelletizing powder silo, and a weighing level meter is provided in the rich ore pelletizing powder silo to detect the material level and control the operation of the feeding system;

[0033] Solid binder is blown into the solid binder silo with the aid of compressed air; a direct-supported belt scale is installed under the solid binder silo, a pressure-type silo-top bag dust collector is installed on the top of the solid binder silo, and a weighing level meter is installed on the solid binder silo to detect the material level and control the operation of the feeding system;

[0034] Optionally, pneumatic conveying is used to transport the internally circulating dust, i.e., dust removal ash, from a pneumatic pipeline to a dust removal ash silo; a direct-supporting belt scale is provided under the dust removal silo, a pressure-type silo-top bag dust collector is provided on the top of the solid binder silo, and a weighing level meter is provided in the dust removal silo to detect the material level and control the operation of the feeding system;

[0035] The rich ore ball-making powder silo, the solid binder silo, and the dust removal ash silo are unloaded according to the set value and transported to the mixing chamber by the belt conveyor. The materials are mixed in the mixing chamber to obtain a mixed material;

[0036] The mixed material is transported to the mixed material silo by a belt conveyor, and discharged into the mixed material silo by a plough discharger, and a liquid binder is added to obtain a mixed material;

[0037] The mixed material is conveyed to the briquetting machine through a belt conveyor equipped with a belt scale, and water is added to obtain pelletizing material;

[0038] Furthermore, each silo is made of steel structure, lined with wear-resistant and anti-sticking lining plates, and a vibrator is installed in the cone section to prevent blockage.

[0039] According to a preferred embodiment of the method for preparing pellets using rich ore powder, the pelletizing is performed using a briquetting machine.

[0040] According to a preferred embodiment of the method for preparing pellets using rich ore powder, the roasting is carried out using a roasting system composed of three main machines, namely, a chain grate, a rotary kiln and an annular cooler;

[0041] Furthermore, the calcination includes drying and preheating the pellets obtained by pelletizing on a chain grate, calcining and consolidating in a rotary kiln, and cooling in a ring cooler;

[0042] Furthermore, drying and preheating on the chain grate includes: sequentially undergoing blast drying, exhaust drying, first-stage preheating, and second-stage preheating; wherein the first-stage preheating is performed using a hot air flow of more than 700° C. (preferably 700-800° C.), and the second-stage preheating is performed using a hot air flow of more than 1000° C. (preferably 1000-1100° C.);

[0043] During the first preheating process, the hot air flow allows the pellets to continue drying and begin oxidation, ensuring that the pellets can withstand the high temperature during the second preheating process;

[0044] During the second stage preheating process, the pellets are further heated and oxidized, and part of the consolidation and hardening is completed, so that the pellets have a certain strength and can withstand the impact when they fall from the chain grate to the rotary kiln, and will not be broken during the rotary motion of the rotary kiln;

[0045] Furthermore, the exhaust drying is performed using a hot air flow of 400-500°C; during the exhaust drying process, air is drawn downward from the top of the material layer to dehydrate and dry the pellets, so that the pellets can withstand the high temperature in the first stage preheating process without bursting; in a specific embodiment, the exhaust drying is performed using the recovered hot exhaust gas from the second stage preheating;

[0046] Furthermore, the calcination temperature during the calcination consolidation process in the rotary kiln is 1250-1280°C;

[0047] Furthermore, during the roasting and consolidation process in the rotary kiln, the pellets are subjected to heat radiation in the kiln, and are roasted while rolling, thereby obtaining uniform strength; the rotation speed of the rotary kiln and the residence time of the pellets in the rotary kiln (usually 25-35 minutes) can be adjusted according to the different raw materials;

[0048] Furthermore, cooling in the ring cooler includes: the pellets are sequentially subjected to first-stage cooling, second-stage cooling, and third-stage cooling, so that the pellet temperature reaches below 150°C;

[0049] Furthermore, the hot air at about 1050-1150°C obtained by the first stage cooling is recycled, and the hot air flow obtained by the first stage cooling is recycled as the hot air flow used for the second stage preheating;

[0050] Furthermore, the hot air at nearly 650-750℃ obtained by the second stage cooling is recycled, and the hot air flow obtained by the second stage cooling is recycled as a supplementary heat source for the first stage preheating;

[0051] Furthermore, the hot air at nearly 300-400°C obtained by the three-stage cooling is recycled, and the hot air flow obtained by the three-stage cooling is recycled as a heat source for blast drying;

[0052] The cooling air volume is automatically adjusted through the cooling machine damper to control the temperature of the reheated air obtained from each cooling section.

[0053] The technical solution provided by the present invention can effectively replace iron ore concentrate with rich ore powder to prepare pellets with an FeO content of no more than 1%, thereby reducing the cost of raw material procurement. Compared with the traditional pellet preparation process, the technical solution provided by the present invention does not require drying pretreatment and high-pressure roller grinding processes, saving construction investment. The technical solution provided by the present invention uses a special pair of rollers and a four-roller series process to crush the rich ore powder, thereby grinding the large-particle rich ore powder to a qualified pelletizing particle size, thereby solving the problem that it is difficult to produce qualified pellets with large-particle rich ore powder, and providing a new direction and new ideas for the development of the pellet industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 The figure is a schematic flow chart of the method for preparing pelletized ore using rich ore powder in Example 1 of the present invention.

[0055] Figure 2 Schematic diagram of the structure of the smooth roller used for smooth roller-to-roller crushing. DETAILED DESCRIPTION

[0056] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below. Here, the exemplary embodiments of the present invention and their description are used to explain the present invention, but are not intended to limit the present invention.

[0057] In the description of this specification, the terms "include", "including", "have", "contain", etc. are all open terms, which mean including but not limited to. The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", etc. mean that the specific features, structures or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps is not limited and can be appropriately adjusted as needed.

[0058] Example 1

[0059] The embodiment of the present invention provides a method for preparing pelletized ore using rich ore powder, the process of which is as follows: Figure 1 As shown, the method includes:

[0060] 1. Crushing of raw materials with rich ore powder, including:

[0061] The rich ore powder enters the crushing system and is successively crushed by four-stage double-roller crushing and two-stage four-roller crushing to prepare rich ore pelletizing powder;

[0062] The four-stage roller crushing includes two stages of carbide spike roller crushing performed first and two stages of smooth roller crushing performed later.

[0063] like Figure 2 As shown, the smooth roller used in the smooth roller-to-roller crushing is hollow and includes a truncated cone section and a cylindrical section. The cylindrical section is connected to one end of the bottom surface with a larger area of ​​the truncated cone section. The side surface of the truncated cone section is used as the grinding surface of the smooth roller. The diameter of the circular holes on the side surface of the cylindrical section of the smooth roller used in the first-stage smooth roller-to-roller crushing is 2 mm, and the diameter of the circular holes on the side surface of the truncated cone section is 1 mm. The diameter of the circular holes on the side surface of the cylindrical section of the smooth roller used in the next-stage smooth roller-to-roller crushing is 1 mm, and the diameter of the circular holes on the side surface of the truncated cone section is 0.5 mm. m, the smooth roller can realize that the materials crushed to the corresponding particle size fall into the inner cavity of the smooth roller truncated cone segment through the circular holes on the side surface of the truncated cone segment, and then roll down to the inner cavity of the smooth roller cylindrical segment, and then fall out of the smooth roller through the circular holes on the side surface of the smooth roller cylindrical segment; the two smooth rollers used in the smooth roller-to-roller crushing are arranged on the same horizontal plane, the truncated cone segments of the two smooth rollers have the same structure, and one end of the bottom surface with a larger area of ​​the truncated cone segment of each smooth roller is flush with one end of the bottom surface with a smaller area of ​​the truncated cone segment of the other smooth roller, and there is no gap between the grinding surfaces of the two smooth rollers;

[0064] Four-stage roller crushing is four-stage roller crushing, including two-stage carbide spike roller crushing and two-stage smooth roller crushing. Four-stage roller crushing can crush materials to diameters below 4mm, diameters below 2mm, diameters below 1mm, and diameters below 0.5mm in sequence. Two-stage four-roller crushing can crush materials to diameters below 0.1mm and diameters below 0.074mm in sequence.

[0065] The matrix material of the carbide pin roller is 42CrMo, and the matrix material of the smooth roller is 42CrMo;

[0066] Each pair of roller crushers and each level of four-roll crushers are powered by Y3553-4 motors and DCY500-50 reducers.

[0067] Among them, the processing capacity of the crushing system is 70t / h;

[0068] The iron-rich powder used in this embodiment includes a mixture of hematite powder and magnetite powder in a mass ratio of 1:1, the total iron content (TFe) of the iron-rich powder is 66%, and the particle size of the iron-rich powder is 0-8mm (excluding 0); the mass content of particles with a particle size not exceeding 0.074mm in the finally prepared rich ore pelletizing powder is not less than 85% (based on the total mass of the rich ore pelletizing powder as 100%).

[0069] 2. Use rich ore ball powder and solid binder, and optionally dust removal ash to prepare a mixed material, including:

[0070] The prepared rich ore pelletizing powder is transported to the top of the batching room by a belt conveyor, and unloaded into the rich ore pelletizing powder silo; a disc feeder with variable frequency speed regulation and an electronic belt scale are provided under the rich ore pelletizing powder silo, a pressure-type silo top bag dust collector is provided on the top of the rich ore pelletizing powder silo, and a weighing level meter is provided in the rich ore pelletizing powder silo to detect the material level and control the operation of the feeding system;

[0071] The bentonite is blown into the bentonite silo with the help of compressed air; a direct-supported belt scale is installed under the bentonite silo, a pressure-type bag dust collector is installed on the top of the solid binder silo, and a weighing level meter is installed in the bentonite silo to detect the material level and control the operation of the feeding system;

[0072] A direct-support belt scale is installed under the dust ash silo, a pressure-type bag dust collector is installed on the top of the solid binder silo, and a weighing level meter is installed in the dust ash silo to detect the material level and control the operation of the feeding system;

[0073] The rich ore pelletizing powder silo, bentonite silo and dust ash silo are unloaded according to the set value (83:15.5:1.5) and transported to the mixing chamber via a belt conveyor. The materials are mixed in the mixing chamber to obtain a mixed material. Among them, the mixing chamber is equipped with a continuous high-power mixer with vertical mixing and a processing capacity of 250t / h. Each silo adopts a steel structure, lined with wear-resistant and anti-sticking lining plates, and a vibrator is installed in the cone section to prevent blockage.

[0074] 3. Mixing the mixed material with a liquid binder (aqueous starch solution) to obtain a mixed material, comprising:

[0075] The mixed material is transported to the mixture silo by a belt conveyor, and unloaded into the mixture silo through a plough-type unloader, and then a liquid binder is added to the mixture silo to obtain a mixture; the mixture silo is equipped with a material level display, and a variable frequency speed-regulating disc feeder is installed under the silo; the belt conveyor used to transport the material to the mixing room is equipped with a moisture detector to detect the moisture content of the mixture, thereby controlling the amount of water added to the mixture silo; each silo adopts a steel structure, lined with wear-resistant and anti-sticking lining plates, and a vibrator is installed in the cone section to prevent blockage.

[0076] 4. Add water to the mixture to obtain pelletizing material, and then make pellets, including:

[0077] The mixture in the mixture silo is conveyed to the briquetting machine by a belt conveyor equipped with a belt scale, water is added to the mixture in the briquetting machine to obtain pelletizing material, and the pelletizing material is pelletized by the briquetting machine to obtain pellets; wherein, the belt conveyor is provided with a moisture detector to detect the moisture content of the mixture, so as to control the amount of water added in the briquetting machine; taking the mass of the pelletizing material as 100%, the moisture content of the pelletizing material is 10%.

[0078] 5. Screening of pellets, including:

[0079] The pellets made by the briquetting machine are screened with a 16mm sieve. The material that falls off the sieve is the screened material, and the material that remains on the sieve is the screen residue.

[0080] The screened material is recycled and specifically transported together with the mixed material in the mixed material silo to the briquetting machine for recycling.

[0081] 6. Balling for material distribution, including:

[0082] The screened material is transported to the raw ball distribution system (aperture 8mm) in the chain grate room by a collecting belt conveyor for distribution. The material remaining on the distribution system is the product after distribution, and the material falling off the distribution system is the distribution residue.

[0083] The cloth residue is recycled, specifically, it is transported together with the mixed material in the mixed material silo to the briquetting machine for recycling.

[0084] 7. The pellets are dried and preheated using a chain grate, including:

[0085] The product after spreading is sequentially passed through the blast drying section on the chain grate for blast drying, the exhaust drying section for exhaust drying, the preheating section I for primary preheating, and the preheating section II for secondary preheating.

[0086] Among them, the blast drying section uses the nearly 350℃ reheated air obtained by three-stage cooling of the ring cooler as the heat source for blast drying of the pellets;

[0087] The exhaust drying section uses the reheated air at about 400℃ obtained by the second stage preheating of the chain grate preheating section II as the heat source to exhaust dry the pellets; during the exhaust drying process, air is drawn downward from the top of the material layer to dehydrate and dry the pellets, so that the pellets can withstand the high temperature in the first stage preheating process without bursting;

[0088] In the first stage of preheating, a hot air flow of about 750°C is used to pass through the material layer to preheat the pellets; in the second stage of the ring cooler, the 700°C reheated air obtained by the second stage cooling is used as a supplementary heat source for the first stage preheating;

[0089] Among them, the preheating stage II uses the first cooling stage of the ring cooler to obtain 1050℃ reheated air through the material layer to perform the second preheating of the pellets.

[0090] 8. The production waste gas discharged by the chain grate enters the electrostatic precipitator for dust removal, and the obtained dust ash is transported to the dust ash silo by pneumatic conveying through the pneumatic pipeline.

[0091] 9. The pellets are roasted and consolidated using a rotary kiln, including:

[0092] The pellets that have been dried and preheated in the grate machine fall into the rotary kiln. The pellets are subjected to heat radiation in the kiln, and are baked and consolidated while rolling, thereby obtaining uniform strength. The temperature in the rotary kiln is 1250-1280℃, and the pellets stay in the rotary kiln for 30 minutes.

[0093] 10. The pellets are cooled by a ring cooler to obtain pellets, including:

[0094] The pellets calcined and consolidated in the rotary kiln enter the ring cooler, and are sequentially cooled through the first cooling section, the second cooling section, the third cooling section, and the third cooling section, so that the pellet temperature reaches below 150°C to obtain pelletized mineral products;

[0095] Among them, the cooling air volume is adjusted by the damper of the ring cooler so that the first stage cooling can obtain nearly 1100℃ reheated air, the second stage cooling can obtain nearly 700℃ reheated air, and the third stage cooling can obtain nearly 350℃ reheated air.

[0096] The FeO content of the pellets obtained in this embodiment is less than 1%.

[0097] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing pelletized ore using rich ore powder, the method comprising: The rich ore powder is subjected to at least four-stage double-roller crushing and at least two-stage four-roller crushing in sequence to prepare rich ore pelletizing powder; wherein the at least four-stage double-roller crushing includes at least two stages of carbide column nail roller double-roller crushing performed first and at least two stages of smooth roller double-roller crushing performed later; the smooth roller used in the smooth roller double-roller crushing is hollow and includes a truncated cone section and a cylindrical section, the cylindrical section is connected to one end of the bottom surface with a large area of ​​the truncated cone section, the side surface of the truncated cone section is used as the grinding surface of the smooth roller, the side surface of the truncated cone section is provided with circular holes consistent with the crushing particle size, and the side surface of the cylindrical section is provided with circular holes with a diameter larger than the diameter of the circular holes on the side surface of the truncated cone section, the smooth roller can realize that the materials crushed to the corresponding particle size fall into the inner cavity of the truncated cone section of the smooth roller through the circular holes on the side surface of the truncated cone section, and then roll down to the inner cavity of the cylindrical section of the smooth roller, and then fall out of the smooth roller through the circular holes on the side surface of the cylindrical section of the smooth roller; The rich ore pelletizing powder is sequentially subjected to pelletizing material preparation, pelletizing, screening, distribution and roasting to obtain the pelletized ore.

2. The method according to claim 1, wherein: The iron-rich powder includes at least one of hematite powder and magnetite powder; The total iron content of the iron-rich powder is not less than 66%; The particle size of the iron-rich powder does not exceed 8 mm.

3. The method according to claim 1, wherein: The diameter of the circular hole on the side surface of the cylindrical section is more than twice the diameter of the circular hole on the side surface of the truncated cone section.

4. The method according to claim 1, wherein: The at least four-stage roller crushing is a four-stage roller crushing, including two-stage carbide spike roller crushing performed first and two-stage smooth roller crushing performed later; the four-stage roller crushing is used to crush the material to a diameter below the A particle size, a diameter below the B particle size, a diameter below the C particle size, and a diameter below the D particle size in sequence; the A particle size is 4-40mm, the B particle size is 2-4mm, the C particle size is 1-2mm, and the D particle size is 0.5-1mm; The at least two-stage four-roller crushing is a two-stage four-roller crushing; the two-stage four-roller crushing can successively crush the material to a diameter below the E particle size and a diameter below the F particle size; the E particle size is 0.1-0.5mm, and the F particle size is 0.074-0.1mm.

5. The method according to claim 1, wherein: The two smooth rollers used in the smooth roller-to-roller crushing are set on the same horizontal plane, the frustum segment structures of the two smooth rollers are the same, and the bottom end of the frustum segment of each roller with a larger area is flush with the bottom end of the frustum segment of the other roller with a smaller area, and there is no gap between the grinding surfaces of the two smooth rollers.

6. The method according to claim 1, wherein: Taking the total mass of the rich ore pelletizing powder as 100%, the mass content of particles with a particle size not exceeding 0.074 mm in the rich ore pelletizing powder is not less than 85%.

7. The method according to claim 1, wherein: Pelletizing material preparation includes: Use rich ore pelletizing powder and solid binder, and optionally dust removal ash for batching; Mixing the batched material with a liquid binder to obtain a mixture; Water is added to the mixture to obtain pelletizing material.

8. The method according to claim 1, wherein: The roasting is carried out using a roasting system consisting of three main machines: a chain grate, a rotary kiln and a ring cooler; the roasting includes: the pellets obtained by pelletizing are dried and preheated on the chain grate, roasted and consolidated in the rotary kiln, and cooled in the ring cooler.

9. The method according to claim 8, wherein: Drying and preheating on the chain grate include: sequentially undergoing blast drying, exhaust drying, first stage preheating, and second stage preheating; wherein the first stage preheating is performed using a hot air flow of 700-800°C; wherein the second stage preheating is performed using a hot air flow of 1000-1100°C; wherein the exhaust drying is performed using a hot air flow of 400-500°C; The calcination temperature during the calcination consolidation process in the rotary kiln is 1250-1280°C; The cooling in the ring cooler includes: the pellets are sequentially subjected to first stage cooling, second stage cooling, and third stage cooling, so that the pellet temperature reaches below 150°C.

10. The method according to claim 9, wherein: The 1050-1150℃ hot air is recovered from the first stage cooling, and the hot air flow obtained from the first stage cooling is recycled as the hot air flow for the second stage preheating; The 650-750℃ hot air is recovered from the second stage cooling, and the hot air flow obtained from the second stage cooling is recycled as a supplementary heat source for the first stage preheating; The 300-400℃ hot air is recovered by three-stage cooling, and the hot air flow obtained by three-stage cooling is recovered as a heat source for blast drying.

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