A dry separation method for high-speed bauxite

Abstract

This application relates to the field of bauxite beneficiation technology, and more particularly to a dry beneficiation method for high-iron bauxite. High-iron bauxite includes iron minerals and aluminum minerals. The dry beneficiation method includes: sequentially crushing and classifying the high-iron bauxite to obtain coarse-grained raw ore, intermediate-grained raw ore, and fine-grained raw ore; dry gravity separation of the coarse-grained raw ore to obtain a first aluminum mineral and a first iron mineral; photoelectric separation of the intermediate-grained raw ore to obtain a second aluminum mineral and a second iron mineral; dry magnetic separation of the fine-grained raw ore to obtain a third aluminum mineral and a third iron mineral; merging the first, second, and third aluminum minerals to obtain aluminum concentrate; merging the first, second, and third iron minerals to obtain iron mineral crude; and finely cleaning the iron mineral crude to obtain iron concentrate product. This dry beneficiation method improves the separation effect of aluminum and iron minerals in high-iron bauxite by differentiating the raw ore of different particle sizes and using a synergistic all-dry process.

Description

Technical Field

[0001] This application relates to the field of bauxite beneficiation technology, and more particularly to a dry beneficiation method for high-speed bauxite. Background Technology

[0002] High-iron bauxite accounts for approximately 70% of imported bauxite. High-iron bauxite refers to bauxite with a mass content of iron minerals (mainly in the form of hematite and limonite) exceeding 25%. Using high-iron bauxite in alumina production presents several problems: Firstly, because the iron minerals cannot participate in the alumina leaching reaction, they are discharged as red mud, increasing the amount of red mud generated compared to low-iron bauxite, thus increasing the subsequent red mud treatment load. Secondly, the iron minerals in high-iron bauxite can react with the alkali solution in the alumina production leaching system, increasing alkali consumption during alumina production and significantly increasing production costs.

[0003] Therefore, high-iron bauxite needs to be screened to remove iron minerals before alumina production. Currently, traditional sorting technologies include wet chemical leaching, flotation, and magnetic separation. However, traditional sorting technologies have certain limitations and cannot solve the problem of efficient separation of aluminum and iron minerals. They lack efficient, low-consumption, and environmentally friendly iron removal and upgrading technologies, which results in low resource utilization and high environmental pressure for high-iron bauxite, making it difficult to achieve comprehensive recovery and efficient utilization of aluminum and iron minerals. Summary of the Invention

[0004] This application provides a dry separation method for high-iron bauxite to solve the following technical problem: how to improve the separation effect of aluminum minerals and iron minerals in high-iron bauxite.

[0005] In a first aspect, embodiments of this application provide a dry separation method for high-iron bauxite, wherein the high-iron bauxite includes iron minerals and aluminum minerals, and the dry separation method includes: The high-iron bauxite is crushed and classified sequentially to obtain coarse-grained raw ore, intermediate-grained raw ore and fine-grained raw ore; The coarse-grained raw ore is subjected to dry gravity separation to separate aluminum minerals and iron minerals in the coarse-grained raw ore, thereby obtaining the first aluminum mineral and the first iron mineral. The intermediate-sized raw ore is subjected to photoelectric separation to separate aluminum minerals and iron minerals in the intermediate-sized raw ore, thereby obtaining a second aluminum mineral and a second iron mineral. The fine-grained raw ore is subjected to dry magnetic separation to separate aluminum and iron minerals in the fine-grained raw ore to obtain a third aluminum mineral and a third iron mineral. The first aluminum mineral, the second aluminum mineral, and the third aluminum mineral are combined to obtain aluminum concentrate; The first iron mineral, the second iron mineral, and the third iron mineral are combined to obtain crude iron mineral; The crude iron ore is refined to obtain iron concentrate.

[0006] Optionally, the separation density of the dry gravity separation is 2.5 g / cm³. 3 Up to 3.2 g / cm 3 The separation airflow velocity of the dry gravity separation is 1.0 m / s to 3.0 m / s.

[0007] Optionally, the dry gravity separation is carried out using an air-heavy medium fluidized bed as the separation device, and the bed thickness of the air-heavy medium fluidized bed is 40mm to 160mm.

[0008] Optionally, the heavy medium used in the dry gravity separation includes magnetite powder and / or inert magnetic beads.

[0009] Optionally, the photoelectric sorting is performed using an X-ray tube as the sorting device, wherein the voltage of the X-ray tube is 100kV to 160kV and the current of the X-ray tube is 1.0mA to 3.0mA.

[0010] Optionally, the material transport speed of the photoelectric sorting is 2.5 m / s to 4.0 m / s.

[0011] Optionally, the magnetic field strength of the dry magnetic separation is 8000 Gs to 15000 Gs; and / or The material transport speed of the dry magnetic sorting is from 0.5 m / min to 2.5 m / min.

[0012] Optionally, the selection is carried out by dry high-intensity magnetic separation, the magnetic field strength of the selection is 3000 Gs to 7000 Gs, and the selection is carried out 1 to 2 times.

[0013] Optionally, the dry gravity separation, the photoelectric separation, the dry magnetic separation, and the fine separation each include pulse dust removal; the pulse dust removal includes cyclone dust removal and bag dust removal, and the wind speed of the pulse dust removal is 0.8m / min to 1.5m / min.

[0014] Optionally, the dry sorting method further includes: The coarse-grained raw ore is subjected to dry gravity separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine dust from the coarse-grained raw ore, and obtain the first aluminum mineral, the first iron mineral and the first fine dust. The intermediate-sized raw ore is subjected to photoelectric separation and pulse dust removal in sequence to separate aluminum minerals and iron minerals in the intermediate-sized raw ore, and obtain second aluminum minerals, second iron minerals and second fine-sized dust. The fine-grained raw ore is subjected to dry magnetic separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine-grained dust in the fine-grained raw ore, and obtain a third aluminum mineral, a third iron mineral and a third fine-grained dust. The first aluminum mineral, the second aluminum mineral, and the third aluminum mineral are combined to obtain aluminum concentrate; The first iron mineral, the second iron mineral, and the third iron mineral are combined to obtain crude iron mineral; The crude iron ore is sequentially refined and subjected to pulse dust removal to obtain a first iron concentrate product, a middlings product, and a fourth fine-particle dust. The intermediate ore products are returned to the crushing process for sequential processing and pulse dust removal to obtain a second iron concentrate product and a fifth fine-particle dust. The first iron concentrate product and the second iron concentrate product are combined to obtain iron concentrate; The first fine-particle dust, the second fine-particle dust, the third fine-particle dust, and the fourth fine-particle dust are combined to obtain fine-particle dust material; The fine-particle dust is returned to the dry magnetic separator for recycling.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a dry separation method for high-iron bauxite. The method first crushes and classifies the aluminum and iron minerals in the high-iron bauxite, dividing it into three independent ranges: coarse-grained, medium-grained, and fine-grained. This lays the foundation for subsequent matching of specific separation processes to different particle sizes, improving separation accuracy from the source. Subsequently, dry gravity separation is applied to the coarse-grained ore. Utilizing the stable flow field of dry gravity separation, the density difference between aluminum and iron minerals in the coarse-grained ore is precisely utilized to separate aluminum and iron minerals. The efficient separation of materials significantly improves the separation accuracy of aluminum and iron minerals in coarse-grained raw ores. For intermediate-grained raw ores, photoelectric separation technology, based on the difference in atomic numbers of aluminum and iron, identifies and precisely sorts each particle of the intermediate-grained raw ores, simultaneously removing gangue impurities while distinguishing aluminum and iron minerals, greatly improving the aluminum-iron separation efficiency of intermediate-grained raw ores. For fine-grained raw ores, dry magnetic separation is used, relying on the difference that aluminum minerals are non-magnetic while iron minerals have characteristic magnetism, to efficiently separate iron and aluminum minerals in fine-grained raw ores. In summary, this dry separation method, through the combined application of dry gravity separation, photoelectric separation, and dry magnetic separation, achieves full coverage recovery of aluminum minerals across all particle sizes of raw ores, including coarse-grained, medium-grained, and fine-grained raw ores, completely eliminating the blind spots in the recovery of specific particle sizes of aluminum minerals by single separation processes, and maximizing the overall recovery rate of aluminum minerals. Meanwhile, the dry separation method combines the iron minerals produced in each separation stage into iron mineral crude product, and then performs a fine cleaning operation on the iron mineral crude product to deeply remove aluminum minerals and gangue impurities mixed in the iron mineral crude product, and finally obtain a high-grade iron concentrate product. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a dry separation method for high-speed bauxite provided in this application embodiment; Figure 2 This is a schematic diagram of a dry separation method for high-speed bauxite provided in an embodiment of this application. Figure 3 A schematic diagram of another dry separation method for high-speed bauxite provided in this application embodiment; Figure 4This is a detailed flowchart illustrating a dry separation method for high-speed bauxite provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The range descriptions used in this application, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "comprising" and others used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships involved in this document, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained by purchasing from the market or by existing methods.

[0021] It should be noted that current traditional sorting technologies have the following drawbacks: (1) Although chemical leaching can achieve a high iron mineral removal rate, the solvent used in chemical leaching will increase the alkali loss in the alumina leaching process, increase the alumina production cost, and at the same time, chemical leaching will also increase the red mud production. (2) The flotation method requires the addition of chemical agents such as collectors and inhibitors, which will increase the reagent cost of the separation technology of high-iron bauxite and may also introduce organic impurities into the bauxite, affecting the subsequent alumina leaching effect. At the same time, the wastewater containing chemical agents generated by the flotation method poses a risk of secondary pollution. (3) Magnetic separation can remove iron minerals before bauxite enters the alumina production process. However, the current magnetic separation method is mainly wet magnetic separation, which requires a lot of water. Moreover, the magnetic properties of iron minerals in high-iron bauxite are relatively weak. Conventional wet magnetic separation equipment has low separation efficiency, and the removal rate of iron minerals is difficult to meet production requirements.

[0022] Based on the aforementioned deficiencies in the prior art, the embodiments of this application provide the following technical solutions: Figure 1 An exemplary schematic diagram of a dry separation method for high-speed bauxite provided in an embodiment of this application is shown. Figure 2 An exemplary schematic diagram of a dry separation method for high-speed bauxite provided in an embodiment of this application is shown. Figure 3 An exemplary schematic diagram of another dry separation method for high-speed bauxite provided in this application embodiment is shown. like Figures 1 to 3 As shown in the embodiment of this application, a dry separation method for high-iron bauxite is provided. The high-iron bauxite includes iron minerals and aluminum minerals. The dry separation method includes: S1. The high-iron bauxite is crushed and classified sequentially to obtain coarse-grained raw ore, intermediate-grained raw ore and fine-grained raw ore; S2. The coarse-grained raw ore is subjected to dry gravity separation to separate aluminum minerals and iron minerals in the coarse-grained raw ore to obtain the first aluminum mineral and the first iron mineral; S3. Perform photoelectric separation on the intermediate-sized raw ore to separate aluminum minerals and iron minerals in the intermediate-sized raw ore to obtain a second aluminum mineral and a second iron mineral; S4. The fine-grained raw ore is subjected to dry magnetic separation to separate aluminum minerals and iron minerals in the fine-grained raw ore to obtain a third aluminum mineral and a third iron mineral; S5. Combine the first aluminum mineral, the second aluminum mineral, and the third aluminum mineral to obtain aluminum concentrate; S6. Combine the first iron mineral, the second iron mineral, and the third iron mineral to obtain crude iron mineral; S7. The crude iron ore is refined to obtain iron concentrate.

[0023] It should be noted that the precision concept of crushing and grading follows the liberation law of the high-iron bauxite crushing process, which proceeds "from intergrowth to individual particles." Different particle sizes of high-iron bauxite are precisely allocated to three dry separation processes with completely different but complementary separation principles. This allows the advantages of each separation technology to be maximized within its most suitable particle size range. Through this grading and separation strategy that leverages the strengths of each, the recovery rate and product grade of iron and aluminum minerals are maximized across the entire particle size range, while ensuring a smooth and efficient separation process. Furthermore, the division into three different particle sizes is not arbitrary but based on the core principles of mineral processing engineering—selective liberation and the matching of optimal separation methods. This is a precise and scientific design tailored to the characteristics of high-iron bauxite. The crushing goal of high-iron bauxite is to separate valuable minerals (such as gibbsite) and iron minerals (such as hematite and goethite) from their tightly coexisting state, forming independent and individual mineral particles. This process is called liberation. Among the minerals obtained from crushing and grading, coarse-grained raw ore (particle size > 10 mm and < 60 mm): Under this particle size condition, aluminum and iron minerals in coarse-grained raw ore have already undergone preliminary individual separation, eliminating the need for further grinding (to avoid over-grinding and aluminum loss). However, the weight and density differences of the mineral particles themselves are already very significant. Medium-grained raw ore (particle size 1 mm to 10 mm): Within this particle size range, the intergrowth relationship of aluminum and iron minerals in medium-grained raw ore is moderate. It lacks the large inclusions of coarse-grained raw ore and the colloidal agglomeration of fine-grained raw ore. Therefore, X-ray sorting equipment used in photoelectric separation can accurately identify minerals based on differences in X-ray penetration (high penetration of aluminum minerals and low penetration of iron minerals). Fine-grained raw ore (particle size < 1 mm): Under this particle size condition, aluminum and iron minerals in fine-grained raw ore have been fully liberated, and most aluminum and iron minerals have become independent single particles. Within this particle size range, the physical properties of the mineral surface are difficult to distinguish due to the small particle size. However, the magnetic difference between aluminum and iron minerals can be used as the most effective sorting basis.

[0024] It should be noted that the alumina content in this high-iron bauxite is below 40%, the ferric oxide content is above 25%, and the iron minerals mainly exist in the high-iron bauxite in the form of goethite and hematite.

[0025] It should be noted that this application provides a dry separation method for high-speed bauxite. This dry separation method, through a full-chain technology design of "precise matching in grading + full-process dry separation + full-particle-size cascade recovery + closed-loop circulation upgrading + terminal fine selection and purification," fundamentally solves the core pain points of traditional single separation processes, such as poor adaptability, low separation accuracy, insufficient resource recovery rate, and numerous interferences from wet processes. It systematically improves the separation effect of aluminum and iron minerals in high-speed bauxite. The specific mechanism is as follows: I. Pre-crushing and grading: laying a solid foundation for monomer dissociation and precise sorting, eliminating sorting interference at the source.

[0026] 1. Crushing to achieve full individual separation of aluminum and iron minerals: Crushing operations break the intergrowth structure of aluminum and iron minerals in high-iron bauxite, achieving full individual separation of the two minerals, providing a core prerequisite for subsequent physical separation: Only when the minerals are completely separated can precise separation be achieved through differences in physical properties, fundamentally avoiding the problems of separation mixing, insufficient product grade, and incomplete aluminum-iron separation caused by intergrowth.

[0027] 2. Classification operation eliminates the core defects of mixed beneficiation: The liberated high-iron bauxite is precisely divided into three independent particle size ranges: coarse, medium and fine. This completely solves the common problems in the industry caused by the mixing of minerals of different particle sizes, such as disordered flow field of the separation medium, inability to take into account separation parameters, and low target mineral capture efficiency. This lays the foundation for matching dedicated separation processes for different particle sizes and improves the accuracy of separation from the source.

[0028] II. Core Grading and Sorting Strategy: Precise matching of particle size and process to achieve efficient separation of aluminum and iron across all particle sizes.

[0029] This application breaks through the limitations of traditional single-stage separation processes. It matches the most suitable dry separation technology to the differences in physical properties of minerals of different particle sizes, maximizing the separation efficiency of aluminum and iron minerals in each particle size, and avoiding the fatal flaw of single-stage processes: "incomplete separation of coarse-grained ore and insufficient recovery of fine-grained ore." 1. Coarse-grained raw ore: Dry gravity separation, adapting to density differences for efficient separation. Coarse-grained raw ore exhibits a significant density difference between liberated aluminum and iron minerals (iron minerals are much denser than aluminum minerals). Dry gravity separation using an air-heavy fluidized bed allows for precise and efficient separation of aluminum and iron minerals through a stable flow field, perfectly suited to the processing characteristics of coarse-grained raw ore. This separation process solves the problems of insufficient accuracy in photoelectric separation and low capture efficiency in magnetic separation of coarse-grained raw ore. It maximizes the recovery of coarse-grained aluminum minerals while simultaneously separating high-purity iron minerals, significantly improving the separation accuracy of aluminum and iron minerals in coarse-grained raw ore.

[0030] 2. Intermediate-Grain Size Raw Ore: X-ray photoelectric separation enables precise separation through particle-by-particle identification. Intermediate-grain size minerals have a moderate particle size. Photoelectric separation uses X-rays to identify and precisely sort intermediate-grain size raw ore based on the difference in atomic numbers between aluminum and iron (iron has an atomic number of 26, while aluminum has an atomic number of 13), accurately distinguishing aluminum and iron minerals while simultaneously removing gangue impurities. This photoelectric separation method solves the problems of unstable flow fields and reduced separation accuracy associated with gravity separation for intermediate-grain size raw ore, as well as the poor particle size compatibility issues with magnetic separation. It significantly improves the aluminum-iron separation efficiency of intermediate-grain size raw ore, ensuring high-purity separation of aluminum and iron minerals.

[0031] 3. Fine-grained raw ore: Dry magnetic separation solves the industry's challenges in fine-grained ore separation. Fine-grained minerals are extremely small, making gravity separation and photoelectric separation ineffective. Based on the difference between non-magnetic aluminum minerals and characteristic magnetic properties of iron minerals, dry magnetic separation can precisely utilize this difference to efficiently separate iron and aluminum minerals in fine-grained raw ore. Simultaneously, this dry magnetic separation method can enclose and return fine-grained dust recovered from pulse dust collectors for reprocessing, completely preventing the loss of fine-grained minerals. This solves the pain points of low recovery rates and severe fine mud loss in traditional separation processes, achieving efficient separation and maximum recovery of aluminum and iron minerals in fine-grained raw ore.

[0032] III. Consolidation of all particle sizes and final selection: dual quality improvement to enhance the deep separation effect of aluminum and iron.

[0033] 1. Aluminum minerals are consolidated across all particle sizes to achieve full recycling coverage: The first, second, and third aluminum minerals obtained from the separation of coarse, medium, and fine-grained raw ore are combined into aluminum concentrate, achieving full-coverage recovery of aluminum minerals across all particle sizes. This completely eliminates the blind spots in the recovery of specific particle sizes of aluminum minerals by single separation processes, maximizing the overall recovery rate of aluminum minerals. Simultaneously, the precise particle size separation method significantly reduces the iron impurity content in the aluminum concentrate, improving the thoroughness of the separation between aluminum and iron minerals.

[0034] 2. Iron mineral merging + final beneficiation for deep purification: The iron minerals obtained from the three-stage separation are merged into a crude iron mineral product, which is then further purified through beneficiation to deeply remove aluminum minerals and gangue impurities, ultimately yielding a high-grade iron concentrate product. This beneficiation step not only further enhances the deep separation of aluminum and iron minerals but also solves the problems of insufficient iron concentrate grade and severe aluminum mineral inclusions in traditional separation processes, significantly increasing the added value of iron products.

[0035] IV. Full-process optimization: Eliminate sorting interference, consolidate separation effect, and achieve cyclical efficiency improvement.

[0036] 1. The all-dry process eliminates interference from water media, ensuring stable sorting accuracy: In traditional wet separation processes, water as a medium easily leads to the mudding of fine-grained minerals and poor slurry dispersion. Furthermore, the addition of flotation reagents can easily disrupt the separation environment, reducing the separation accuracy of aluminum and iron minerals. The dry separation method of this application employs dry separation throughout the entire process, eliminating the need for water as a separation medium. This fundamentally prevents problems such as mineral mudding, reagent interference, and unstable slurry flow, ensuring long-term stability of the separation accuracy throughout the process. Simultaneously, it avoids the loss of fine-grained minerals with wastewater in wet processes, further consolidating the separation and recovery effects of aluminum and iron minerals.

[0037] 2. Closed-loop recycling of intermediate-grained ore for secondary improvement in sorting efficiency: By constructing a closed-loop recycling system for intermediate-grained ore, intermediate products from the sorting process are returned to the corresponding stage for reprocessing. Minerals that are not fully liberated or poorly sorted undergo secondary sorting, further improving the liberation and separation of aluminum and iron minerals and avoiding the loss of valuable minerals in the intermediate-grained ore. Simultaneously, fine-grained dust recovered by pulse dust collectors is returned to the fine-grained magnetic separation stage, preventing the loss of valuable minerals in the fine-grained dust, achieving full utilization of resources, and further improving the overall separation and recovery effect.

[0038] 3. Pre-sorting reinforces the overall resource recovery effect: The precise sorting of the dry sorting method in this application significantly reduces the content of impurities such as iron and silicon in aluminum concentrate, reduces the amount of red mud produced in the subsequent Bayer process for alumina production, avoids aluminum mineral loss caused by impurities in subsequent processes, and in turn improves the overall recovery effect of aluminum resources, thus achieving full-chain reinforcement of the sorting effect.

[0039] In some optional embodiments, the dry gravity separation has a separation density of 2.5 g / cm³. 3 Up to 3.2 g / cm 3 The separation airflow velocity of the dry gravity separation is 1.0 m / s to 3.0 m / s.

[0040] In these embodiments, the sorting density is 2.5 g / cm³. 3 Up to 3.2 g / cm 3 Dry gravity separation with a separation airflow velocity of 1.0 m / s to 3.0 m / s can form a stable flow field, so as to accurately utilize the density difference to achieve efficient separation of aluminum and iron minerals. This not only maximizes the recovery of coarse-grained aluminum minerals, but also simultaneously separates high-purity iron minerals, greatly improving the separation accuracy of aluminum and iron minerals in coarse-grained raw ore.

[0041] The separation density of this dry gravity separation can be 2.5 g / cm³.3 2.6g / cm 3 2.7g / cm 3 2.8g / cm 3 2.9g / cm 3 3.0g / cm 3 3.1g / cm 3 Or 3.2g / cm 3 .

[0042] The separation airflow velocity of this dry gravity separator can be 1.0 m / s, 1.1 m / s, 1.2 m / s, 1.3 m / s, 1.4 m / s, 1.5 m / s, 2.0 m / s, 2.5 m / s or 3.0 m / s.

[0043] It should be noted that the separation airflow velocity is the primary condition for forming a stable fluidized bed and achieving effective separation. Air-based heavy media fluidized beds suspend dry solid media particles (such as magnetite powder, inert magnetic beads, etc.) through airflow, forming a pseudo-fluid bed with fluid-like properties. A suitable separation airflow velocity ensures that the heavy media fluidized bed maintains uniform and stable fluidization, possessing stable density and good flowability, providing an ideal environment for density-based stratification of coarse-grained raw ore.

[0044] It should be noted that when the separation airflow velocity in dry gravity separation exceeds 3.0 m / s, the heavy medium fluidized bed will fluctuate violently, resulting in uneven separation density. Excessively high separation airflow velocities can also create large bubbles and even cause "surge" and "channeling" phenomena, disrupting the uniformity of the heavy medium fluidized bed and leading to uneven separation density distribution, thus reducing the accuracy of dry gravity separation. Furthermore, excessively high separation airflow velocities can cause material to be blown out, affecting the grade of the overflow product. Conversely, excessively low separation airflow velocities can prevent the heavy medium fluidized bed from fully fluidizing, leading to airflow short-circuiting or mineral particle accumulation, making it difficult for mineral particles to separate into layers. This results in a sharp drop in separation efficiency, or even prevents the completion of dry gravity separation altogether.

[0045] In some optional embodiments, the dry gravity separation is carried out using an air-heavy medium fluidized bed as the separation device, and the bed thickness of the air-heavy medium fluidized bed is 40 mm to 160 mm.

[0046] In these embodiments, an air-heavy fluidized bed with a bed thickness of 40 mm to 160 mm can form a distinct strong product layer (floating matter, aluminum minerals) and a heavy product layer (sinking matter, iron minerals) during dry gravity separation, and the aluminum minerals and iron minerals are separated and discharged by a discharge device (e.g., a scraper or an overflow weir).

[0047] The bed thickness of this air-heavy medium fluidized bed can be 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm or 160mm.

[0048] It should be noted that when the bed thickness of the air-heavy medium fluidized bed exceeds 160mm, the bed resistance during dry gravity separation increases, requiring higher fan pressure. This directly leads to increased energy consumption in dry gravity separation, resulting in excessively long stratification times between aluminum and iron minerals and reducing the throughput of coarse-grained ore. Furthermore, excessive bed thickness can cause already stratified mineral particles to remix due to localized eddies or bubble disturbances, thus reducing the accuracy of dry gravity separation. When the bed thickness of the air-heavy medium fluidized bed is less than 40mm, the stratification space for mineral particles is reduced, resulting in insufficient travel time between aluminum and iron minerals to complete stratification. This leads to poor separation of minerals with similar densities, resulting in iron minerals mixed with aluminum minerals, or aluminum minerals containing iron minerals. Ultimately, this results in extremely poor bed stability of the air-heavy medium fluidized bed, making it susceptible to airflow fluctuations and causing large fluctuations in the grades of the first aluminum and first iron minerals.

[0049] In some alternative embodiments, the heavy medium used in the dry gravity separation includes magnetite powder and / or inert magnetic beads.

[0050] In these embodiments, a heavy medium including magnetite powder and / or inert magnetic beads is used. A stable flow field can be formed by the magnetite powder or inert magnetic beads. These flow fields can accurately utilize density differences to achieve efficient separation of aluminum and iron minerals. This maximizes the recovery of coarse-grained aluminum minerals and simultaneously separates high-purity iron minerals, significantly improving the separation accuracy of aluminum and iron minerals in coarse-grained raw ore.

[0051] In some optional embodiments, the photoelectric sorting is performed using an X-ray tube as the sorting device, the voltage of the X-ray tube being 100kV to 160kV and the current of the X-ray tube being 1.0mA to 3.0mA.

[0052] In these embodiments, X-ray tubes with voltages of 100kV to 160kV and currents of 1.0mA to 3.0mA provide sufficient energy for photoelectric separation to penetrate aluminum and iron minerals in intermediate-grained ore, accurately distinguish between them, and simultaneously remove gangue impurities from the intermediate-grained ore. This significantly improves the aluminum-iron separation efficiency of the intermediate-grained ore and ensures high-purity separation of aluminum and iron minerals in the intermediate-grained ore.

[0053] The voltage of the X-ray tube can be 100kV, 110kV, 120kV, 130kV, 140kV, 150kV or 160kV.

[0054] The current of the X-ray tube can be 1.0mA, 1.1mA, 1.2mA, 1.3mA, 1.4mA, 1.5mA, 2.0mA, 2.5mA or 3.0mA.

[0055] It should be noted that during the photoelectric sorting process, ores of different densities have different absorption capabilities for X-rays. As a result, the signal intensity received by the receiver of the XRT photoelectric sorting machine will vary. The image processing system constructs an internal density image of the ore based on the signal intensity and separates the target mineral from impurities using high-pressure gas.

[0056] It should be noted that the voltage of the X-ray tube determines the maximum energy of the photons emitted by the X-ray tube, ensuring that the X-rays have sufficient ability to penetrate intermediate-grained raw ore. This allows the X-rays to penetrate aluminum and iron mineral particles (especially dense minerals or larger-diameter particles) in the intermediate-grained raw ore, identify the internal composition or density differences of the intermediate-grained raw ore, and produce sufficient image contrast.

[0057] It should be noted that when the X-ray tube voltage is higher than 160kV, although X-rays can penetrate intermediate-grained ore better, the image contrast is lower, making the signal difference between the target mineral and gangue impurities smaller. This makes it difficult for the detector in the XRT photoelectric separator to distinguish subtle density differences, resulting in a decrease in the accuracy of photoelectric separation. When the X-ray tube voltage is lower than 100kV, X-rays cannot penetrate thicker or denser ore in intermediate-grained ore, resulting in very weak or even zero signals received by the detector in the XRT photoelectric separator, making it difficult to effectively identify the ore. This leads to the omission of ore in intermediate-grained ore, causing the loss of target minerals or the mixing of gangue impurities.

[0058] It should be noted that the X-ray current determines the number of X-ray photons (flux), affecting the signal-to-noise ratio and image brightness. When the X-ray tube current exceeds 3.0 mA, the X-ray dose is too high, making the detector in the XRT photoelectric sorting machine prone to overload and saturation, resulting in overexposure and misjudgments. Simultaneously, excessive X-ray tube current leads to increased anode loss, increasing the failure rate of the XRT photoelectric sorting machine. When the X-ray tube current is below 1.0 mA, the X-ray intensity is insufficient, making the detector signal in the XRT photoelectric sorting machine susceptible to noise interference, affecting the sorting process and resulting in poor image quality. This leads to decreased recognition accuracy and reliability in photoelectric sorting; furthermore, dry sorting methods cannot reliably identify the characteristics of intermediate-sized ore particles, reducing both the efficiency and throughput of photoelectric sorting.

[0059] In some alternative embodiments, the material transport speed of the photoelectric sorting is from 2.5 m / s to 4.0 m / s.

[0060] In these embodiments, photoelectric separation with a material transport speed of 2.5 m / s to 4.0 m / s enables uniform photoelectric separation of intermediate-sized ore. This allows the X-rays from photoelectric separation to penetrate the aluminum and iron minerals in the intermediate-sized ore, accurately distinguishing between them and simultaneously removing gangue impurities. This significantly improves the aluminum-iron separation efficiency of the intermediate-sized ore, ensuring high-purity separation of aluminum and iron minerals in the intermediate-sized ore.

[0061] The material transport speed of this photoelectric sorting system can be 2.5m / s, 2.6m / s, 2.7m / s, 2.8m / s, 2.9m / s, 3.0m / s, 3.5m / s, or 4.0m / s.

[0062] It should be noted that the material transport speed in photoelectric sorting is mainly controlled by the conveyor belt, which directly determines the processing capacity and execution time of the XRT photoelectric sorting machine. When the material transport speed exceeds 4.0 m / s, the residence time of intermediate-sized ore in the XRT photoelectric sorting machine is too short, resulting in insufficient X-ray scanning. Simultaneously, the detector of the XRT photoelectric sorting machine has insufficient time to process signals, increasing the false judgment rate. Furthermore, excessively fast material transport speeds can cause intermediate-sized ore to easily deviate from the detection area due to inertia, reducing the accuracy of photoelectric sorting. When the material transport speed is less than 2.5 m / s, intermediate-sized ore cannot meet the detection requirements of photoelectric sorting, and it tends to accumulate and overlap on the transport equipment, obstructing X-ray detection by the X-ray tube, thus hindering the smooth operation of photoelectric sorting.

[0063] In some alternative embodiments, the magnetic field strength of the dry magnetic separation is 8000 Gs to 15000 Gs; and / or The material transport speed of the dry magnetic sorting is from 0.5 m / min to 2.5 m / min.

[0064] In these embodiments, dry magnetic separation with a magnetic field strength of 8000 Gs to 15000 Gs and a material transport speed of 0.5 m / min to 2.5 m / min can efficiently separate iron and aluminum minerals in fine-grained raw ore. In addition, dry magnetic separation can seal and return fine-grained dust recovered by pulse dust removal for reprocessing, completely avoiding the loss of fine-grained minerals and achieving efficient separation and maximum recovery of aluminum and iron minerals in fine-grained raw ore.

[0065] The magnetic field strength of this dry magnetic separator can be 8000Gs, 9000Gs, 10000Gs, 11000Gs, 12000Gs, 13000Gs, 14000Gs or 15000Gs.

[0066] The material transport speed of this dry magnetic separator can be 0.5m / min, 0.6m / min, 0.7m / min, 0.8m / min, 0.9m / min, 1.0m / min, 1.5m / min, 2.0m / min or 2.5m / min.

[0067] It should be noted that a high-gradient permanent magnet drum separator can be used for dry magnetic separation. The high-gradient permanent magnet drum separator provides sufficient magnetic force for dry magnetic separation of weakly magnetic minerals in fine-grained minerals. At the same time, the magnetic field strength of the dry magnetic separation is optimized and adjusted according to the differences in the magnetic strength of different weakly magnetic minerals to achieve the best dry magnetic separation effect.

[0068] It should be noted that when the magnetic field strength of dry magnetic separation exceeds 15000 Gs, the high magnetic field strength will result in severe mechanical inclusions in the fine-grained ore, leading to a decrease in the grade of tertiary aluminum and tertiary iron minerals. When the magnetic field strength of dry magnetic separation is below 8000 Gs, the magnetic field strength is insufficient to capture weakly magnetic mineral particles in the fine-grained ore, causing a large number of valuable mineral particles to be lost with the tailings, thus reducing the recovery rate of the target minerals.

[0069] It should be noted that the material transport speed of dry magnetic separation determines the effective residence time of fine-grained ore in the dry magnetic separation stage. Sufficient operating time is crucial for efficient separation and maximum recovery of aluminum and iron minerals in the fine-grained ore. When the material transport speed exceeds 2.5 m / min, the residence time of fine-grained ore in the dry magnetic separation stage is short, resulting in insufficient separation time and a decreased recovery rate of weakly magnetic mineral particles. When the material transport speed is below 0.5 m / min, the processing capacity of fine-grained ore in the dry magnetic separation stage is insufficient, causing weakly magnetic mineral particles to remain on the surface of the high-gradient permanent magnet drum separator used in the dry magnetic separation for an extended period, leading to material accumulation and a decrease in the efficiency of the dry magnetic separation.

[0070] In some alternative implementations, the selection is carried out by dry high-intensity magnetic separation, with a magnetic field strength of 3000 Gs to 7000 Gs, and the selection is performed once to twice.

[0071] In these embodiments, a magnetic field strength of 3000 Gs to 7000 Gs and a number of selections of 1 to 2 times can screen out target minerals with strong magnetic properties from crude iron ore, thereby obtaining high-purity iron concentrate products.

[0072] The selected magnetic field strength can be 3000Gs, 3500Gs, 4000Gs, 4500Gs, 5000Gs, 5500Gs, 6000Gs, 6500Gs or 7000Gs.

[0073] It should be noted that the controlled beneficiation is carried out by dry high-intensity magnetic separation, and the magnetic field strength of the beneficiation is controlled to be 3000Gs to 7000Gs. This can effectively screen out the target minerals with strong magnetic properties from the iron ore crude product, thereby obtaining a high-purity iron concentrate product.

[0074] It should be noted that when the magnetic field strength during the selection process exceeds 7000 Gs, the iron ore roughage accumulates and coats the surface of the magnetic rollers used in dry high-intensity magnetic separation, affecting the subsequent passage of the iron ore roughage and the separation effect of the selection process. Although it can improve the grade of the iron concentrate, the overall grade improvement is limited. When the magnetic field strength during the selection process is below 3000 Gs, some target minerals in the iron ore roughage that have already been liberated but are fine-sized or have weak magnetic properties cannot be effectively captured during the selection process. These target minerals are lost in subsequent selection processes, resulting in excessive loss of iron concentrate recovery rate.

[0075] In some optional embodiments, the dry gravity separation, the photoelectric separation, the dry magnetic separation, and the fine separation each include pulse dust removal; the pulse dust removal includes cyclone dust removal and bag dust removal, and the wind speed of the pulse dust removal is 0.8 m / min to 1.5 m / min.

[0076] In these embodiments, a pulse dust removal stage is set in the dry gravity separation, photoelectric separation, dry magnetic separation and cleaning process. The fine dust generated in the cleaning and each separation stage can be collected by pulse dust removal, which is beneficial to the subsequent collection of target minerals in these fine dusts by dry magnetic separation to form high-grade and high-yield iron concentrate products.

[0077] The pulse dust collector can have an air velocity of 0.8 m / min, 0.9 m / min, 1.0 m / min, 1.1 m / min, 1.2 m / min, 1.3 m / min, 1.4 m / min or 1.5 m / min.

[0078] Figure 4 A detailed flowchart of a dry separation method for high-speed bauxite provided in an embodiment of this application is illustrated by way of example. In some alternative implementations, such as Figure 4 As shown, the dry sorting method further includes: S201. The coarse-grained raw ore is subjected to dry gravity separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine-grained dust in the coarse-grained raw ore to obtain the first aluminum mineral, the first iron mineral and the first fine-grained dust. S301. The intermediate-sized raw ore is subjected to photoelectric separation and pulse dust removal in sequence to separate aluminum minerals and iron minerals in the intermediate-sized raw ore, and obtain second aluminum minerals, second iron minerals and second fine-sized dust. S401. The fine-grained raw ore is subjected to dry magnetic separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine-grained dust in the fine-grained raw ore, and obtain a third aluminum mineral, a third iron mineral and a third fine-grained dust. S5. Combine the first aluminum mineral, the second aluminum mineral, and the third aluminum mineral to obtain aluminum concentrate; S6. Combine the first iron mineral, the second iron mineral, and the third iron mineral to obtain crude iron mineral; S701. The crude iron ore is sequentially fined and pulse dust removed to obtain a first iron concentrate product, a middlings product, and a fourth fine dust. S702. The middlings product is returned to the crushing process for sequential processing and pulse dust removal to obtain a second iron concentrate product and a fifth fine-particle dust. S8. Combine the first iron concentrate product and the second iron concentrate product to obtain iron concentrate; S9. The first fine-particle dust, the second fine-particle dust, the third fine-particle dust and the fourth fine-particle dust are combined to obtain fine-particle dust material; S10. The fine-particle dust is returned to the dry magnetic sorting system for recycling.

[0079] In these embodiments, fine-grained dust obtained from dry gravity separation, photoelectric separation, dry magnetic separation, and fine selection is collected, as well as fifth-grade fine-grained dust from the crushing of middlings products. Finally, the target minerals in these fine-grained dusts are screened out by dry magnetic separation, thereby improving the grade and yield of iron minerals.

[0080] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0081] Example 1 The high-iron bauxite used includes alumina, iron oxide and silicon oxide components. The mass fraction of alumina is 39.86%, the mass fraction of silicon oxide is 3.04%, and the mass fraction of iron oxide is 31.68%.

[0082] like Figure 3 and Figure 4 As shown, a dry separation method for high-iron bauxite, which includes iron minerals and aluminum minerals, includes: S1. The high-iron bauxite is crushed and classified sequentially to obtain coarse-grained raw ore (>10mm), medium-grained raw ore (1mm to 10mm) and fine-grained raw ore (<1mm). S201. The coarse-grained raw ore is subjected to dry gravity separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine-grained dust in the coarse-grained raw ore to obtain the first aluminum mineral, the first iron mineral and the first fine-grained dust. S301. The intermediate-sized raw ore is subjected to photoelectric separation and pulse dust removal in sequence to separate aluminum minerals and iron minerals in the intermediate-sized raw ore, and obtain second aluminum minerals, second iron minerals and second fine-sized dust. S401. The fine-grained raw ore is subjected to dry magnetic separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine-grained dust in the fine-grained raw ore, and obtain a third aluminum mineral, a third iron mineral and a third fine-grained dust. S5. Combine the first aluminum mineral, the second aluminum mineral, and the third aluminum mineral to obtain aluminum concentrate; S6. Combine the first iron mineral, the second iron mineral, and the third iron mineral to obtain crude iron mineral; S701. The crude iron ore is sequentially fined and pulse dust removed to obtain a first iron concentrate product, a middlings product, and a fourth fine dust. S702. The middlings product is returned to the crushing process for sequential processing and pulse dust removal to obtain a second iron concentrate product and a fifth fine-particle dust. S8. Combine the first iron concentrate product and the second iron concentrate product to obtain iron concentrate; S9. The first fine-particle dust, the second fine-particle dust, the third fine-particle dust and the fourth fine-particle dust are combined to obtain fine-particle dust material; S10. The fine-particle dust is returned to the dry magnetic sorting system for recycling.

[0083] The separation density of dry gravity separation is 3.1 g / cm³. 3 The separation airflow velocity in dry gravity separation is 2.5 m / s.

[0084] Dry gravity separation is carried out using an air-heavy medium fluidized bed as the separation equipment, with a bed thickness of 160 mm.

[0085] The heavy medium used in dry gravity separation is magnetite powder.

[0086] Photoelectric sorting is performed using an X-ray tube as the sorting device. The voltage of the X-ray tube is 140kV and the current of the X-ray tube is 2.0mA.

[0087] The material transport speed of photoelectric sorting is 3.5 m / s.

[0088] The magnetic field strength for dry magnetic separation is 12000 Gs; The material transport speed of dry magnetic separation is 1.5 m / min.

[0089] The selection was carried out by dry high-intensity magnetic separation, and the selection was carried out twice, with magnetic field strengths of 7000 Gs and 3000 Gs respectively.

[0090] Dry gravity separation, photoelectric separation, dry magnetic separation and fine separation each include pulse dust removal; pulse dust removal includes cyclone dust removal and bag dust removal, and the air velocity of pulse dust removal is 1.0m / min.

[0091] Example 2 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The high-iron bauxite used includes alumina, iron oxide and silicon oxide components. The mass fraction of alumina is 35.82%, the mass fraction of silicon oxide is 4.89%, and the mass fraction of iron oxide is 34.23%.

[0092] The separation density of dry gravity separation is 2.7 g / cm³. 3 The separation airflow velocity in dry gravity separation is 1.5 m / s.

[0093] The bed thickness of the air-heavy medium fluidized bed is 100 mm.

[0094] The heavy medium used in dry gravity separation is inert magnetic beads.

[0095] The voltage of the X-ray tube is 100kV, and the current of the X-ray tube is 1.0mA.

[0096] The material transport speed of photoelectric sorting is 2.5 m / s.

[0097] The magnetic field strength for dry magnetic separation is 8000 Gs; The material transport speed of dry magnetic separation is 2.5 m / min.

[0098] The selected magnetic field strength is 4000 Gs, and the selection is performed once.

[0099] The air velocity of the pulse dust collector is 0.8 m / min.

[0100] Example 3 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The high-iron bauxite used includes alumina, iron oxide and silicon oxide components. The mass fraction of alumina is 38.21%, the mass fraction of silicon oxide is 3.17%, and the mass fraction of iron oxide is 33.03%.

[0101] The separation density of dry gravity separation is 3.2 g / cm³. 3 The separation airflow velocity of dry gravity separation is 3.0 m / s.

[0102] The bed thickness of the air-heavy medium fluidized bed is 70 mm.

[0103] The heavy medium used in dry gravity separation is a mixture of magnetite powder and inert magnetic beads (the mass ratio of magnetite powder to inert magnetic beads is 1:1).

[0104] The voltage of the X-ray tube is 120kV, and the current of the X-ray tube is 2.5mA.

[0105] The material transport speed of photoelectric sorting is 4.0 m / s.

[0106] The magnetic field strength for dry magnetic separation is 15000 Gs; The material transport speed of dry magnetic separation is 2.0 m / min.

[0107] The selection was performed twice, with magnetic field strengths of 6000 Gs and 4000 Gs respectively.

[0108] The air velocity for pulse dust removal is 1.5 m / min.

[0109] Example 4 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The high-iron bauxite used includes alumina, iron oxide and silicon oxide components. The mass fraction of alumina is 36.55%, the mass fraction of silicon oxide is 4.05%, and the mass fraction of iron oxide is 33.96%.

[0110] The separation density of dry gravity separation is 2.5 g / cm³. 3 The separation airflow velocity in dry gravity separation is 1.0 m / s.

[0111] The bed thickness of the air-heavy medium fluidized bed is 40 mm.

[0112] The voltage of the X-ray tube is 160kV, and the current of the X-ray tube is 3.0mA.

[0113] The material transport speed of photoelectric sorting is 3.0 m / s.

[0114] The magnetic field strength for dry magnetic separation is 10000 Gs; The material transport speed of dry magnetic separation is 0.5 m / min.

[0115] The selected magnetic field strength is 7000 Gs, and the selection is performed once.

[0116] The air velocity of the pulse dust collector is 1.2 m / min.

[0117] Example 5 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The high-iron bauxite used includes alumina, iron oxide and silicon oxide components, with a mass fraction of 37.48% for alumina, 3.57% for silicon oxide and 33.42% for iron oxide.

[0118] The separation density of dry gravity separation is 2.9 g / cm³. 3 The separation airflow velocity of dry gravity separation is 2.0 m / s.

[0119] The bed thickness of the air-heavy medium fluidized bed is 130 mm.

[0120] The voltage of the X-ray tube is 130kV, and the current of the X-ray tube is 1.5mA.

[0121] The material transport speed of photoelectric sorting is 3.5 m / s.

[0122] The heavy medium used in dry gravity separation is inert magnetic beads.

[0123] The magnetic field strength for dry magnetic separation is 14000 Gs; The material transport speed of dry magnetic separation is 1.0 m / min.

[0124] The selected magnetic field strength is 5000 Gs, and the selection is performed once.

[0125] The air velocity of the pulse dust collector is 1.2 m / min.

[0126] Comparative Example 1 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: Coarse-grained raw ore is obtained solely through crushing without grading.

[0127] Dry gravity separation is performed on coarse-grained raw ore to separate aluminum and iron minerals, thus obtaining aluminum and iron minerals.

[0128] The separation density of dry gravity separation is 3.1 g / cm³. 3 The separation airflow velocity in dry gravity separation is 2.5 m / s.

[0129] The bed thickness of the air-heavy medium fluidized bed is 160 mm.

[0130] Comparative Example 2 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The intermediate-sized ore is obtained by crushing without grading.

[0131] Photoelectric separation is performed on intermediate-sized raw ore to separate aluminum and iron minerals, thus obtaining aluminum and iron minerals.

[0132] The voltage of the X-ray tube is 140kV, and the current of the X-ray tube is 2.0mA.

[0133] The material transport speed of photoelectric sorting is 3.5 m / s.

[0134] Comparative Example 3 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: Fine-grained ore is obtained solely through crushing without grading.

[0135] Dry magnetic separation is performed on fine-grained raw ore to separate aluminum and iron minerals from intermediate-grained raw ore, thus obtaining aluminum and iron minerals.

[0136] The voltage of the X-ray tube is 140kV, and the current of the X-ray tube is 2.0mA.

[0137] The material transport speed of photoelectric sorting is 3.5 m / s.

[0138] Relevant experimental and effect data: Aluminum and iron minerals obtained from each embodiment and comparative example were collected, and the composition of these aluminum and iron minerals was analyzed. The results are shown in Table 1.

[0139] Table 1. Composition distribution of aluminum and iron minerals in each embodiment and comparative example.

[0140] As shown in Table 1, the embodiments of this application provide a dry separation method for high-speed bauxite. This dry separation method, through a full-chain technology design of "precise matching of grades + full-process dry separation + full-particle-level cascade recovery + closed-loop circulation quality improvement + terminal fine selection and purification", fundamentally solves the core pain points of traditional single separation processes, such as poor adaptability, low separation accuracy, insufficient resource recovery rate, and many interferences from wet processes, and systematically improves the separation effect of aluminum minerals and iron minerals in high-speed bauxite.

[0141] Compared to Example 1, Comparative Examples 1 to 3 only formed raw ore of a single particle size through crushing, and used dry gravity separation, photoelectric separation and dry magnetic separation for the needle-like nature of raw ore of different particle sizes. This made it difficult to separate high-grade aluminum or iron minerals from the raw ore of each particle size. As a result, aluminum minerals contained some iron minerals, and iron minerals contained some aluminum minerals, making it difficult to effectively separate aluminum and iron minerals in high-iron bauxite.

[0142] In summary, the embodiments of this application provide a dry separation method for high-iron bauxite. This dry separation method performs differentiated processing on raw ore of different particle sizes. Through a synergistic dry process involving dry gravity separation, photoelectric separation, dry magnetic separation, and fine separation, it can obtain aluminum minerals with an alumina content of more than 45% and iron minerals with an alumina content of less than 20.0% and an iron oxide content of more than 65%. This allows both the aluminum and iron minerals obtained by the dry separation method to be sold as products, indicating that aluminum and iron minerals in high-iron bauxite are efficiently separated.

[0143] In addition, this application provides a dry separation method for high-iron bauxite, which achieves efficient separation of aluminum and iron minerals in high-iron bauxite through the following mechanism: I. Precise sorting by particle size enables simultaneous improvement in the grade and recovery rate of aluminum and iron ore.

[0144] This dry separation method breaks through the limitations of traditional single separation processes. It innovatively adopts a graded separation strategy, employing dry gravity separation, photoelectric separation, dry magnetic separation, and finer dry separation technologies tailored to the physical characteristics of different particle sizes of raw ore. This achieves efficient liberation and precise separation of aluminum and iron minerals in high-iron bauxite. It ensures maximum recovery of aluminum minerals across different particle sizes, while simultaneously recovering the separated iron minerals, ultimately yielding high-quality iron concentrate with an iron oxide content ≥65%. This makes the product value and resource recovery rate of this dry separation method far exceed those of traditional separation processes.

[0145] Second, the all-dry process saves water completely, and is significantly more environmentally friendly and adaptable.

[0146] Traditional wet separation processes (such as wet magnetic separation and flotation) require 5m³ of fuel to process 1 ton of high-iron bauxite. 3 up to 8m 3 Water resources, and generate 1m 3 up to 3m 3 The muddy wastewater requires additional wastewater treatment costs. This dry separation method uses dry separation technology throughout the entire process, eliminating the need for water as a separation medium and fundamentally preventing the generation of mineral processing wastewater and tailings slurry. It not only solves the water pollution and tailings dam safety problems of traditional wet separation processes, but also makes this technology particularly suitable for mineral resource development in water-scarce areas, greatly expanding the usable range of high-iron bauxite resources, and its environmental friendliness is significantly superior to traditional processes.

[0147] Third, resources are fully recycled to achieve the dual goals of reduction and recycling.

[0148] This dry separation method utilizes a closed-loop recycling system for intermediate-grained ore to reprocess intermediate products generated during the dry separation process. Simultaneously, fine-grained dust recovered by pulse dust collectors is returned to the fine-grained ore via a closed-loop dry magnetic separation system, mitigating the problem and preventing the intermediate-grained ore and fine-grained dust from being stockpiled as solid waste. Furthermore, through precise separation, the impurity content in high-iron bauxite is reduced, and red mud production is decreased by 10% to 20% compared to the conventional Bayer process, achieving the dual goals of resource utilization and significant solid waste reduction.

[0149] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A dry separation method for high-iron bauxite, wherein the high-iron bauxite comprises iron minerals and aluminum minerals, characterized in that, The dry sorting method includes: The high-iron bauxite is crushed and classified sequentially to obtain coarse-grained raw ore, intermediate-grained raw ore and fine-grained raw ore; The coarse-grained raw ore is subjected to dry gravity separation to separate aluminum minerals and iron minerals in the coarse-grained raw ore, thereby obtaining the first aluminum mineral and the first iron mineral. The intermediate-sized raw ore is subjected to photoelectric separation to separate aluminum minerals and iron minerals in the intermediate-sized raw ore, thereby obtaining a second aluminum mineral and a second iron mineral. The fine-grained raw ore is subjected to dry magnetic separation to separate aluminum and iron minerals in the fine-grained raw ore to obtain a third aluminum mineral and a third iron mineral. The first aluminum mineral, the second aluminum mineral, and the third aluminum mineral are combined to obtain aluminum concentrate; The first iron mineral, the second iron mineral, and the third iron mineral are combined to obtain crude iron mineral; The crude iron ore is refined to obtain iron concentrate.

2. The dry sorting method according to claim 1, characterized in that, The separation density of the dry gravity separation is 2.5 g / cm³. 3 Up to 3.2 g / cm 3 The separation airflow velocity of the dry gravity separation is 1.0 m / s to 3.0 m / s.

3. The dry sorting method according to claim 1, characterized in that, The dry gravity separation is carried out using an air-heavy medium fluidized bed as the separation equipment, and the bed thickness of the air-heavy medium fluidized bed is 40mm to 160mm.

4. The dry sorting method according to claim 3, characterized in that, The heavy medium used in the dry gravity separation includes magnetite powder and / or inert magnetic beads.

5. The dry sorting method according to claim 1, characterized in that, The photoelectric sorting is performed using an X-ray tube as the sorting device. The voltage of the X-ray tube is 100kV to 160kV, and the current of the X-ray tube is 1.0mA to 3.0mA.

6. The dry sorting method according to claim 1, characterized in that, The material transport speed of the photoelectric sorting is 2.5 m / s to 4.0 m / s.

7. The dry sorting method according to claim 1, characterized in that, The magnetic field strength of the dry magnetic separation is 8000 Gs to 15000 Gs; and / or The material transport speed of the dry magnetic sorting is from 0.5 m / min to 2.5 m / min.

8. The dry sorting method according to claim 1, characterized in that, The selection is carried out by dry high-intensity magnetic separation, with a magnetic field strength of 3000 Gs to 7000 Gs, and the selection is performed once to twice.

9. The dry sorting method according to claim 1, characterized in that, The dry gravity separation, photoelectric separation, dry magnetic separation, and fine separation each include pulse dust removal; the pulse dust removal includes cyclone dust removal and bag dust removal, and the wind speed of the pulse dust removal is 0.8 m / min to 1.5 m / min.

10. The dry sorting method according to claim 9, characterized in that, The dry sorting method further includes: The coarse-grained raw ore is subjected to dry gravity separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine dust from the coarse-grained raw ore, and obtain the first aluminum mineral, the first iron mineral and the first fine dust. The intermediate-sized raw ore is subjected to photoelectric separation and pulse dust removal in sequence to separate aluminum minerals and iron minerals in the intermediate-sized raw ore, and obtain second aluminum minerals, second iron minerals and second fine-sized dust. The fine-grained raw ore is subjected to dry magnetic separation and pulse dust removal in sequence to separate aluminum minerals, iron minerals and fine-grained dust in the fine-grained raw ore, and obtain a third aluminum mineral, a third iron mineral and a third fine-grained dust. The first aluminum mineral, the second aluminum mineral, and the third aluminum mineral are combined to obtain aluminum concentrate; The first iron mineral, the second iron mineral, and the third iron mineral are combined to obtain crude iron mineral; The crude iron ore is sequentially refined and subjected to pulse dust removal to obtain a first iron concentrate product, a middlings product, and a fourth fine-particle dust. The intermediate ore products are returned to the crushing process for sequential processing and pulse dust removal to obtain a second iron concentrate product and a fifth fine-particle dust. The first iron concentrate product and the second iron concentrate product are combined to obtain iron concentrate; The first fine-particle dust, the second fine-particle dust, the third fine-particle dust, and the fourth fine-particle dust are combined to obtain fine-particle dust material; The fine-particle dust is returned to the dry magnetic separator for recycling.

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