Method for extracting magnesium from uranium-bearing humites

Abstract

The application discloses a kind of boron magnesio-iron ore containing uranium magnesium extraction beneficiation methods, adopt multi-section closed circuit crushing classification, stage grinding gradient magnetic separation, strong magnetic weak magnetic combined impurity removal, targeted magnesium extraction combination process, first simultaneously realize the efficient recovery of iron, uranium valuable elements, then grade enrichment magnesium-containing minerals from iron tailings, finally through the targeted purification process of precipitation and high gradient magnetic separation impurity removal, dehydration, calcination preparation high-purity magnesium powder;The application has the advantages that: whole-process closed loop is efficient, realize the collaborative comprehensive recovery of iron, uranium, magnesium in boron magnesio-iron ore, and the problems of low magnesium recovery rate, insufficient product purity, complex process and high environmental pressure in the existing process are solved; No strong acid and strong alkali and other high-pollution reagents are used throughout the process, the equipment combination is compact, the process parameters are controllable, the energy consumption and production cost are low, it is suitable for industrial large-scale production, and the comprehensive utilization rate of boron magnesio-iron ore resources is improved.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a mineral processing technology for extracting magnesium ore from iron tailings of uranium-boron-magnesium iron ore. Background Technology

[0002] Boron-magnesium iron ore, a strategic symbiotic mineral resource in my country, has the chemical composition (Mg,Fe)2Fe(BO3)O2, with MgO content reaching 22%~42%. It also contains associated valuable elements such as B2O3 (6%~8.5%) and TFe (26%~32%). The proven reserves in the Liaodong region alone reach 280 million tons, making it a mineral resource with comprehensive recovery value for boron, magnesium, and iron. With the continuous growth in global demand for magnesium resources from lightweight materials, chemical flame retardants, and other fields, and the increasing depletion of easily beneficiated single magnesium ore resources, extracting magnesium from boron-magnesium iron ore has become a direction for alleviating the supply and demand contradiction of magnesium resources and improving the comprehensive utilization rate of mineral resources.

[0003] The mineralogical characteristics of boromagnesite present the following challenges to magnesium ore extraction: First, the close intergrowth of minerals such as boromagnesite, magnetite, and serpentine in the ore, along with their complex intergrowth structure and fine-grained boromagnesite, makes it difficult to effectively separate valuable minerals from gangue minerals using conventional mechanical separation. Second, magnesium is mainly found in magnesium-bearing minerals such as boromagnesite and serpentine, and exists in a symbiotic state with iron and boron. Conventional separation processes can easily lead to interference between magnesium and other valuable elements, making separation difficult. Third, impurities such as S, Al2O3, and SiO2 in the ore can easily be mixed into the magnesium product during the separation process, affecting product purity and industrial applications.

[0004] The currently disclosed boron-magnesium iron ore processing technologies mainly focus on the recovery of boron and iron. The special process for magnesium ore extraction is not yet perfect. The existing related technologies have the following defects: (1) Some processes adopt multi-stage grinding and multiple reagent adjustment processes, which have high energy consumption and high production costs. Moreover, the magnesium recovery rate is generally lower than 75%, resulting in serious resource waste. (2) Wet leaching technology mostly uses high-concentration inorganic or organic acids. Although it can improve the leaching rate, it is highly corrosive to equipment, puts great pressure on environmental protection, and is prone to insufficient purity of magnesium products due to iron interference. (3) Selective reduction-magnetic separation process requires the use of binders to form agglomerates, which increases production costs and may also introduce impurities such as Na, K, and Si, affecting the quality of magnesium products. At the same time, this process has strict requirements on the particle size and grade of raw materials, and its application scope is limited. (4) Existing processes mostly focus on the recovery of single elements and fail to achieve the synergistic separation of boron, magnesium, and iron, resulting in low comprehensive utilization rate of resources and poor economic benefits during magnesium extraction.

[0005] In summary, existing borosilicate ore processing technologies suffer from problems such as low magnesium ore recovery rates, insufficient product purity, complex processes, high costs, and significant environmental impact, making it difficult to meet the demands of industrial-scale magnesium ore extraction. Therefore, developing a beneficiation process that adapts to the mineral characteristics of borosilicate ore, achieves magnesium ore separation, and balances comprehensive resource utilization with environmental protection requirements has significant industrial application value and strategic importance. Summary of the Invention

[0006] This invention provides a method for magnesium extraction and beneficiation from uranium-boron-magnesium iron ore, the technical solution of which is as follows:

[0007] A method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore, used to process uranium-boron-magnesium iron ore with a TFe content of 26%~32%, MgO content of 22%~42%, and B2O3 content of 6%~8.5%, includes the following steps:

[0008] S1 Crushing and Grading Steps

[0009] Raw ore with a particle size of 300mm~1000mm is processed by coarse crushing and medium crushing in sequence and then sent to dry screening. The material on the screen is returned to the medium crushing, and the material under the screen is processed by high-pressure roller mill and then transported to the powder silo.

[0010] S2 Wet Screening - Tailings Sweeping Step

[0011] After the material in the ore bin is mixed with water to form a slurry, it is transported to a wet screening machine. The material over the screen is subjected to a dry tailings discharge treatment. Magnetic minerals are returned to the intermediate crusher, and non-magnetic minerals are discharged as surrounding rock. The material under the screen is sent to a wet tailings discharge magnetic separation machine. The wet tailings discharge tailings are sent to a scavenging process. The concentrate from the scavenging process is combined with the concentrate from the wet tailings discharge and sent to a ball mill. The tailings from the scavenging process are sent to the uranium gravity separation process.

[0012] S3 First-stage grinding-classification-magnetic separation steps

[0013] The ore discharge from ball mill 1 is sent to hydraulic classification 1 for classification. The classified sediment is returned to ball mill 1, and the classification overflow is sent to magnetic separation 1 for treatment. The tailings from magnetic separation 1 are sent to scavenging 2 for treatment. The concentrate from scavenging 2 is combined with the concentrate from magnetic separation 1 and then sent to high frequency screening. The tailings from scavenging 2 are sent to hydraulic classification 2.

[0014] S4 Two-Stage Grinding - Classification - Magnetic Separation Steps

[0015] The oversize material from the high-frequency screening is sent to the concentration magnetic separation treatment. The concentration magnetic separation concentrate is sent to the ball mill II for grinding. The grinding discharge and the concentration magnetic separation tailings are returned to the high-frequency screening. The undersize material from the high-frequency screening is processed sequentially by magnetic separation II and magnetic separation III. The magnetic separation III concentrate is vacuum filtered to produce iron concentrate. The tailings from magnetic separation II and magnetic separation III are combined and sent to scavenging III for processing. The scavenging III concentrate is returned to the high-frequency screening. The scavenging III tailings are sent to hydraulic classification III.

[0016] S5 Magnesium Ore Pre-Enrichment and Uranium Recovery Procedures

[0017] The sediment from hydraulic classification II and hydraulic classification III is combined and sent to the uranium gravity separation process. The overflow from hydraulic classification II and hydraulic classification III is combined and sent to the inclined plate sedimentation tank for treatment.

[0018] S6 Magnesium Ore Purification and Finished Product Preparation Steps

[0019] The overflow water from the inclined plate sedimentation tank is sent to the large well, and the sedimentation bottom flow is sent to the vertical ring magnetic separator for treatment; the concentrate from the vertical ring magnetic separator is sent to the large well, and the tailings from the vertical ring magnetic separator are sent to the plate and frame filter press for dewatering treatment. The dewatered filter cake is calcined to produce magnesium concentrate, and the filter water from the plate and frame filter press is sent to the large well.

[0020] In step S1, a jaw crusher is used for coarse crushing with a discharge opening of 170mm; a cone crusher is used for medium crushing with a discharge opening of 45mm; a double-layer circular vibrating screen with a screen opening of 12mm is used for dry screening; and the working pressure of the high-pressure roller mill is set to 90bar.

[0021] In step S2, wet screening uses a linear screen with a 5mm aperture; wet tail throwing uses a drum magnetic separator with a magnetic field strength of 120KA / m~165KA / m; and scavenging uses a drum magnetic separator with a magnetic field strength of 350KA / m~500KA / m.

[0022] In step S3, ball milling I uses an overflow ball mill, and the proportion of -0.074mm particles in the ground product is 45%~55%; hydraulic classification I uses a hydrocyclone with a diameter of 500mm; magnetic separation I uses a drum magnetic separator with a magnetic field strength of 120KA / m~165KA / m; scavenging II uses a drum magnetic separator with a magnetic field strength of 350KA / m~500KA / m; and high-frequency screening uses a five-layer high-frequency screen with a screen aperture of 0.1mm.

[0023] In step S4, ball milling II uses an overflow ball mill, and the proportion of -0.074mm particles in the ground product is 80%~85%; magnetic separation II and magnetic separation III use drum magnetic separators with a magnetic field strength of 120KA / m~165KA / m; scavenging III uses a drum magnetic separator with a magnetic field strength of 350KA / m~500KA / m; the filtrate produced by vacuum filtration is returned to magnetic separation II as makeup water.

[0024] In step S5, a hydrocyclone with a diameter of 500 mm and an operating pressure of 0.08 MPa to 0.11 MPa is used for hydraulic classification II; a hydrocyclone with a diameter of 100 mm and an operating pressure of 0.08 MPa to 0.11 MPa is used for hydraulic classification III; flocculants are added during the treatment process in the inclined plate sedimentation tank.

[0025] In step S6, the vertical ring magnetic separator adopts a vertical ring pulsating high gradient magnetic separator with a rotation frequency of 15Hz, an excitation current of 650A, and an excitation voltage of 25V; the plate and frame filter press adopts a programmable diaphragm plate and frame filter press.

[0026] This invention has the following characteristics:

[0027] 1. By combining grinding and sorting, magnesium minerals are enriched and iron and uranium elements are recovered simultaneously, thereby improving resource utilization.

[0028] 2. By setting up a sorting process, magnesium minerals can be separated from iron- and boron-containing minerals, providing a pathway for the utilization of magnesium resources in borosilicate ore.

[0029] 3. This invention adopts a combined magnetic and gravity beneficiation process, which does not use strong acid or strong alkali reagents, and the wastewater can be treated and reused, meeting the environmental protection requirements for mineral beneficiation. Attached Figure Description

[0030] Figure 1 is a flowchart of the working process of the present invention. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] This implementation plan targets uranium-boron-magnesium iron ore with a TFe content of 26%~32%, MgO content of 22%~42%, and B2O3 content of 6%~8.5%. It adopts a combined magnetic and gravity beneficiation process of "crushing-wet tailings disposal-two-stage grinding and magnetic separation-uranium-magnesium diversion and recovery-magnesium extraction and purification" to achieve the separation and recovery of the three components of iron, uranium, and magnesium.

[0033] Raw material preparation

[0034] (a) Properties of the raw ore

[0035] Mineral composition: Iron minerals are mainly found in magnetite; magnesium is mainly found in boromagnesite and serpentine; boron is mainly found in boromagnesite with a small amount in borophorite; uranium minerals are crystalline uranium ore; and sulfur exists as pyrrhotite and pyrite. The minerals in the ore are closely interrelated, with a complex interlocking structure; magnetite and boromagnesite are fine-grained. Raw material specifications: The raw ore has a particle size of 300mm~1000mm and contains no large pieces of waste rock or impurities.

[0036] (II) Requirements for raw material pretreatment

[0037] After the raw ore arrives at the site, it is piled up evenly to prevent it from getting wet and clumping, ensuring continuous feeding in the crushing process; large pieces of waste rock in the raw ore are sorted and removed in advance.

[0038] List of core equipment and technical parameters

[0039] sheet

[0040] Process Stage Equipment Name Model / Specification Key technical parameters Crushing system Jaw crusher 170mm discharge port Cone crusher (medium crusher) Adapt to medium-breakage requirements 45mm discharge port Double-layer circular vibrating screen (dry screening) 12mm sieve aperture High-pressure roller mill Work pressure 90 bar Linear screen (wet screening) 5mm sieve aperture Grinding and Classification System Overflow ball mill (ball mill type 1) Grinding particle size - 0.074mm accounts for 45%~55% Overflow ball mill (ball mill II) Grinding particle size - 0.074mm accounts for 80%~85% Hydrocyclone (Hydraulic Classification 1) 500mm in diameter Used for classifying grinding products in a first stage Hydrocyclone (Hydraulic Classification II) 500mm in diameter Pressure 0.08 MPa ~ 0.11 MPa Hydrocyclone (Hydraulic Classification III) 100mm in diameter Pressure 0.08 MPa ~ 0.11 MPa Five-layer high frequency screen 0.1mm sieve aperture Magnetic separation system Drum magnetic separator (wet tailings removal / magnetic separation type I / II / III) Weak magnetic type Magnetic field strength 120KA / m~165KA / m Drum magnetic separator (sweeping type I / II / III) Strong magnetic type Magnetic field strength 350 kA / m ~ 500 kA / m Concentrated magnetic separator Suitable for high-frequency screen material sorting Vertical ring pulsating high gradient magnetic separator Rotation frequency 15Hz, excitation current 650A, excitation voltage 25V Magnesium extraction auxiliary system Inclined plate sedimentation tank Programmable diaphragm plate and frame filter press Calcination equipment Suspension calcining furnace Large well / sedimentation tank NXZ-9 Auxiliary equipment Pump pool, slurry pump belt conveyor

[0041] Detailed implementation steps

[0042] S1 Closed-Circuit Crushing and Classification Process

[0043] Primary crushing: Raw ore with a particle size of 300mm~1000mm is conveyed to the jaw crusher via belt. The discharge opening is set to 170mm. The raw ore is crushed to a particle size of -170mm. The crushed material is then conveyed to the intermediate crushing process via belt.

[0044] Medium crushing operation: After coarse crushing, the material is fed into a cone crusher with a discharge opening of 45mm to crush the material to a particle size of -45mm. The crushed material is then conveyed by belt to a double-layer circular vibrating screen for dry screening.

[0045] Dry grading closed circuit: The screen aperture of the double-layer circular vibrating screen is set to 12mm. The material with a diameter of +12mm on the screen is returned to the intermediate crusher by belt for further crushing, forming a closed-circuit crushing cycle to ensure that the crushed particle size meets the standard; the material with a diameter of -12mm on the screen is conveyed to the high-pressure roller mill by belt.

[0046] High-pressure roller mill: -12mm material is fed into the high-pressure roller mill, and the working pressure is set to 90 bar. The ore is roller-pressed to achieve the separation of minerals along the grain boundaries and avoid over-grinding which would damage the structure of magnesium-containing minerals. The high-pressure roller mill discharge is conveyed to the powder silo for buffering via belt.

[0047] S2 Wet Screening - Tailings Scavenging Process

[0048] Wet grading: The material in the powder ore bin is conveyed to the pump pool by belt, mixed with water to prepare a qualified slurry, and then conveyed by the slurry pump to a linear screen with a screen size of 5mm for wet grading.

[0049] Dry tailings treatment: The material exceeding 5mm from the wet screening screen is conveyed to the dry tailings process by belt conveyor. Magnetic minerals are separated by magnetic separation and returned to the intermediate crusher for recycling via belt conveyor. Non-magnetic minerals are discharged separately as surrounding rock, thus reducing the subsequent grinding load.

[0050] Wet tailings disposal and scavenging: The material undersized by wet screening (-5mm) is fed into a wet tailings magnetic separator, where a weak magnetic field with a strength of 120KA / m~165KA / m is used for separation to obtain iron-containing mixed concentrate and tailings; the tailings are sent to scavenging stage 1, where a strong magnetic field with a strength of 350KA / m~500KA / m is used for secondary scavenging to recover a small amount of iron-containing minerals entrained therein; the concentrate from scavenging stage 1 and the wet tailings disposal concentrate are combined and sent to ball mill stage 1; the tailings from scavenging stage 1 are sent to the uranium gravity separation process to achieve early diversion and recovery of uranium ore.

[0051] S3 Single-stage grinding-classification-magnetic separation process

[0052] First-stage closed-circuit grinding: The mixed concentrate is fed into an overflow ball mill (ball mill one) for first-stage grinding, controlling the proportion of -0.074mm particles in the grinding product to 45%~55%, ensuring the initial liberation of iron minerals and magnesium-containing minerals.

[0053] Closed-loop hydraulic classification: The discharge from ball mill 1 is fed into a 500mm diameter hydrocyclone (hydraulic classification 1) for classification. The underflow is returned to ball mill 1 via a slurry pump, forming a closed-loop grinding system to ensure that the grinding particle size is stable and meets the standards. The overflow from the classification is sent to magnetic separation 1 for treatment.

[0054] Gradient magnetic separation: The overflow from the graded separation is fed into a drum magnetic separator (magnetic separation one) with a magnetic field strength of 120KA / m~165KA / m for weak magnetic separation, separating magnetite concentrate and tailings rich in magnesium and boron; the tailings from magnetic separation one are fed into a drum magnetic separator (scavenging separation two) with a magnetic field strength of 350KA / m~500KA / m for strong magnetic scavenging, recovering a small amount of magnetite entrained therein; the concentrate from scavenging separation two is combined with the concentrate from magnetic separation one and fed into a five-layer high-frequency screen with a screen aperture of 0.1mm; the tailings from scavenging separation two are fed into hydraulic classification two, realizing the first step of pre-enrichment of magnesium ore.

[0055] S4 Two-stage grinding-classification-multi-stage magnetic separation process

[0056] Two-stage closed-circuit grinding: The material oversize by the high-frequency screening is fed into a thickening magnetic separator for magnetic enrichment. The thickened magnetic separator concentrate is fed into an overflow ball mill (ball mill II) for two-stage deep grinding, controlling the proportion of -0.074mm particles in the grinding product to 80%~85%, ensuring complete liberation of magnetite. The grinding discharge from ball mill II and the thickening magnetic separator tailings are returned to the high-frequency screening, forming a two-stage closed-circuit grinding system.

[0057] Multi-stage magnetic separation purification: The undersize material from the high-frequency screening is sequentially fed into magnetic separation stage II and magnetic separation stage III for two-stage weak magnetic refining. The magnetic field strength is controlled at 120KA / m~165KA / m. The concentrate from magnetic separation stage III is sent to a vacuum filter for dewatering to produce the final iron concentrate. The tailings from magnetic separation stage II and magnetic separation stage III are combined and sent to scavenging stage III, where a strong magnetic field with a strength of 350KA / m~500KA / m is used for scavenging to recover the small amount of magnetite entrained therein. The concentrate from scavenging stage III is returned to the high-frequency screening for recycling and separation. The tailings from scavenging stage III are sent to hydraulic classification stage III to achieve the second step of pre-enrichment of magnesium ore.

[0058] Filtrate reuse: The filtrate produced by vacuum filtration is returned to the magnetic separation process II as makeup water, realizing closed-loop water resource reuse.

[0059] S5 Magnesium Ore Pre-Enrichment and Uranium Recovery Process

[0060] Graded desliming and separation: The second hydraulic stage uses a hydrocyclone with a diameter of 500 mm and an operating pressure of 0.08 MPa to 0.11 MPa, while the third hydraulic stage uses a hydrocyclone with a diameter of 100 mm and an operating pressure of 0.08 MPa to 0.11 MPa. The tailings from the two stages of iron ore beneficiation are graded and deslimed separately. The sludge from the two hydraulic stages is combined and sent to the uranium gravity separation process to recover uranium ore. The proportion of magnesium-containing minerals in the overflow from the classification is significantly increased. After being combined, the sludge is sent to an inclined plate sedimentation tank for precipitation and enrichment.

[0061] Sedimentation and enrichment: A small amount of flocculant is added to the inclined plate sedimentation tank to accelerate the sedimentation of magnesium-containing minerals, realize the separation of magnesium-containing minerals from fine-particle sludge, complete the deep pre-enrichment of magnesium ore, and reduce the processing load for subsequent purification processes.

[0062] S6 Magnesia Ore Purification and Finished Product Preparation Process

[0063] High-gradient magnetic separation for impurity removal: The overflow water from the inclined plate sedimentation tank is sent to the large well for centralized treatment, and the sedimentation underflow is sent to the vertical ring pulsating high-gradient magnetic separator. The rotating frequency is controlled at 15Hz, the excitation current is 650A, and the excitation voltage is 25V. The high-gradient magnetic field removes the fine ferromagnetic impurities entrained in the underflow, greatly improving the purity of magnesium ore. The concentrate from the vertical ring magnetic separator is sent to the large well for centralized treatment.

[0064] Dehydration and calcination purification: The tailings from the vertical ring magnetic separator are sent to a programmable diaphragm plate and frame filter press for deep dehydration. The dehydrated filter cake is sent to a rotary kiln for calcination to remove bound water and residual organic impurities from the minerals, ultimately yielding high-grade magnesium concentrate. The filter water produced by the plate and frame filter press is sent to a large well for centralized treatment.

Claims

1. A method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore, used to process uranium-boron-magnesium iron ore with a TFe content of 26%~32%, MgO content of 22%~42%, and B2O3 content of 6%~8.5%, characterized in that, Includes the following steps: S1 Crushing and Grading Process The raw ore is processed by coarse crushing and medium crushing in sequence and then sent to dry screening. The material on the screen is returned to the medium crushing to form a closed-circuit crushing cycle, and the material under the screen is processed by high-pressure roller mill and then sent to the powder ore silo for buffering. S2 Wet Screening-Tail-Scavenging Process After the material in the powder ore bin is mixed with water to form a slurry, it is conveyed to the wet screening. The material over the screen is subjected to dry tailings treatment, in which magnetic minerals are returned to the intermediate crushing and recycling process, and non-magnetic minerals are discharged separately as surrounding rock. The material under the screen is sent to the wet tailings magnetic separation process, and the wet tailings are sent to the scavenging process. The concentrate from the scavenging process is combined with the concentrate from the wet tailings and sent to the ball mill. The tailings from the scavenging process are sent to the uranium gravity separation process. S3 One-stage grinding-classification-magnetic separation process The discharge from ball mill 1 is sent to hydraulic classification 1 for classification. The classified sediment is returned to ball mill 1 to form a closed-circuit grinding system. The classification overflow is sent to magnetic separation 1 for treatment. The tailings from magnetic separation 1 are sent to scavenging separation 2 for treatment. The concentrate from scavenging separation 2 is combined with the concentrate from magnetic separation 1 and sent to high frequency screening. The tailings from scavenging separation 2 are sent to hydraulic classification 2. S4 Two-stage grinding-classification-multi-stage magnetic separation process The oversize material from the high-frequency screening is sent to the concentration magnetic separation treatment. The concentration magnetic separation concentrate is sent to the ball mill II for grinding. The grinding discharge and the concentration magnetic separation tailings are returned to the high-frequency screening to form a two-stage closed-circuit grinding system. The undersize material from the high-frequency screening is sequentially treated by two-stage magnetic separation II and magnetic separation III. The magnetic separation III concentrate is vacuum filtered to produce the final iron concentrate. The tailings from magnetic separation II and magnetic separation III are combined and sent to the scavenging III treatment. The scavenging III concentrate is returned to the high-frequency screening for recycling and separation. The scavenging III tailings are sent to the hydraulic classification III. S5 Magnesium Ore Pre-Enrichment and Uranium Recovery Process The sediment from hydraulic classification II and hydraulic classification III is combined and sent to the uranium gravity separation process. The overflow from hydraulic classification II and hydraulic classification III is combined and sent to the inclined plate sedimentation tank for sedimentation and enrichment treatment. S6 Magnesium Ore Purification and Finished Product Preparation Process The overflow water from the inclined plate sedimentation tank is sent to the large well, and the sedimentation bottom flow is sent to the vertical ring magnetic separator for impurity removal and purification. The concentrate from the vertical ring magnetic separator is sent to the large well, and the tailings from the vertical ring magnetic separator are sent to the plate and frame filter press for dewatering. The dewatered filter cake is calcined to produce the final magnesium concentrate, and the filter water from the plate and frame filter press is sent to the large well.

2. The method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore as described in claim 1, characterized in that, In step S1, a closed-circuit crushing system consisting of three-stage crushing and high-pressure roller mill is used to achieve precise control of ore particle size and preliminary mineral liberation: a jaw crusher is used for coarse crushing, with the discharge opening controlled at 170mm, to crush the raw ore to a particle size of -170mm; a cone crusher is used for intermediate crushing, with the discharge opening controlled at 45mm, to crush the material to a particle size of -45mm; a double-layer circular vibrating screen with a screen aperture of 12mm is used for dry screening, and the material above the screen with a +12mm aperture is returned to the intermediate crusher for further crushing, forming a closed-circuit cycle; the material below the screen with a -12mm aperture is sent to a high-pressure roller mill with a working pressure of 90bar for processing.

3. The method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore as described in claim 1, characterized in that, In step S2, a combination of wet grading, dry tailings throwing, and gradient magnetic separation tailings throwing is used to achieve pre-diversion: wet screening uses a linear screen with a 5mm screen aperture to achieve secondary control of ore particle size; the surrounding rock separated by dry tailings throwing is discharged from the system in advance; wet tailings throwing uses a drum magnetic separator with a magnetic field strength of 120KA / m~165KA / m; scavenging one uses a strong magnetic drum magnetic separator with a magnetic field strength of 350KA / m~500KA / m. Iron-containing minerals are recovered through gradient magnetic fields, while uranium-containing and magnesium-containing tailings are diverted in advance.

4. The method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore as described in claim 1, characterized in that, In step S3, ball milling I uses an overflow ball mill to ensure the initial liberation of iron minerals from magnesium-containing minerals; hydraulic classification I uses a 500mm diameter hydrocyclone to control the grinding particle size and avoid over-grinding; magnetic separation I uses a weak magnetic drum separator with a magnetic field strength of 120KA / m~165KA / m, and scavenging II uses a strong magnetic drum separator with a magnetic field strength of 350KA / m~500KA / m. Through gradient magnetic separation, iron minerals are enriched and recovered, while the tailings from scavenging II, which are rich in magnesium minerals, are directionally fed into hydraulic classification II to achieve the first step of pre-enrichment of magnesium ore.

5. The method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore as described in claim 1, characterized in that, In step S3, ball milling I uses an overflow ball mill, and the proportion of -0.074mm particles in the ground product is 45%~55%; hydraulic classification I uses a hydrocyclone with a diameter of 500mm; magnetic separation I uses a drum magnetic separator with a magnetic field strength of 120KA / m~165KA / m; scavenging II uses a drum magnetic separator with a magnetic field strength of 350KA / m~500KA / m; and high-frequency screening uses a five-layer high-frequency screen with a screen aperture of 0.1mm.

6. The method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore as described in claim 1, characterized in that, In step S4, ball milling II uses an overflow ball mill, and the proportion of -0.074mm particles in the ground product is 80%~85%; magnetic separation II and magnetic separation III use drum magnetic separators with a magnetic field strength of 120KA / m~165KA / m; scavenging III uses a drum magnetic separator with a magnetic field strength of 350KA / m~500KA / m; the filtrate produced by vacuum filtration is returned to magnetic separation II as makeup water.

7. The method for magnesium extraction and beneficiation of uranium-boron-magnesium iron ore as described in claim 1, characterized in that, In step S5, a hydrocyclone with a diameter of 500 mm and an operating pressure of 0.08 MPa to 0.11 MPa is used for hydraulic classification II; a hydrocyclone with a diameter of 100 mm and an operating pressure of 0.08 MPa to 0.11 MPa is used for hydraulic classification III; flocculants are added during the treatment process in the inclined plate sedimentation tank.

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