Gravity concentration and impurity removal beneficiation system for treating low-grade bauxite
Patent Information
- Application Number
- AU2025390487
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-11-26
- Filing Date
- 2025-03-14
- Publication Date
- 2026-09-17
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Chinese Patent Application No. 202411699532.9, filed on November 26, 2024. The disclosure of the aforementioned application is hereby incorporated by reference in its entirety. TECHNICAL FIELD
[0002] The disclosure relates to the technical field of mineral processing, and in particular, to a gravity separation beneficiation system for impurity removal from a low-grade bauxite. BACKGROUND
[0003] As high-grade bauxite resources are increasingly depleted, an aluminum-silicon ratio of bauxite used by alumina enterprises has dropped significantly. Currently, industrialized impurity removal technologies for bauxite mainly include a flotation desulfurization technology for a high-sulfur bauxite and a flotation desiliconization technology for a low-grade bauxite. However, the flotation desulfurization technology and the flotation desiliconization technology have problems such as a high cost, a complex process, a high energy consumption for fine grinding and liberation of ores, and difficulties in stockpile and disposal caused by reagent residues, a fine particle size and a high water content in a flotation tailing, resulting in a low profit margin for alumina enterprises when using bauxite concentrate to produce alumina, and thus a development of a desiliconization technology for the low-grade bauxite is severely restricted. SUMMARY
[0004] The disclosure aims to solve at least one of the technical problems existing in the conventional technologies or related art.
[0005] To this end, the disclosure provides a gravity separation beneficiation system for impurity removal from a low-grade bauxite.
[0006] In view of this, according to an embodiment of the disclosure, a gravity separation beneficiation system for impurity removal from a low-grade bauxite is proposed, including: a crushing unit, configured to crush a raw material to obtain a crushed material; a pretreatment and classification unit, configured to pretreat the crushed material, and classify the crushed material after being pretreated according to a preset dimension to obtain a first size fraction material and a second size fraction material, where a particle size of the first size fraction material is greater than a particle size of the second size fraction material; a first gravity separation unit, configured to perform a gravity separation for impurity removal on the first size fraction material to obtain a first size fraction gravity separation concentrate and a first size fraction gravity separation tailing; a second gravity separation unit, configured to perform a gravity separation for impurity removal on the second size fraction material to obtain a second size fraction gravity separation concentrate and a second size fraction gravity separation tailing; and a sedimentation and filter press unit, configured to sediment and pressure filter the second size fraction gravity separation concentrate and the second size fraction gravity separation tailing to obtain a dewatered second size fraction product. BRIEF DESCRIPTION OF DRAWINGS
[0007] Various other advantages and benefits will become clear to a person of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the disclosure. Moreover, throughout the drawings, the same reference numerals are used to denote the same components. In the drawings:
[0008] FIG. 1 is a schematic architecture diagram of a gravity separation beneficiation system for impurity removal from a low-grade bauxite according to some embodiments of the disclosure.
[0009] FIG. 2 is a schematic structural diagram of a gravity separation beneficiation system for impurity removal from a low-grade bauxite according to some embodiments of the disclosure.
[0010] FIG. 3 is a schematic structural diagram of a first dense medium cyclone of a gravity separation beneficiation system for impurity removal from a low-grade bauxite according to some embodiments of the disclosure;
[0011] FIG. 4 is a schematic structural diagram of a first dual-channel medium draining and washing screen of a gravity separation beneficiation system for impurity removal from a low-grade bauxite according to some embodiments of the disclosure, from one angle;
[0012] FIG. 5 is a schematic structural diagram of the first dual-channel medium draining and washing screen of a gravity separation beneficiation system for impurity removal from a low-grade bauxite according to some embodiments of the disclosure, from another angle;
[0013] FIG. 6 is a schematic structural diagram of a double-drum centrifugal concentrator of a gravity separation beneficiation system for impurity removal from a low-grade bauxite according to some embodiments of the disclosure, from one angle;
[0014] FIG. 7 is a schematic structural diagram of the double-drum centrifugal concentrator of the gravity separation beneficiation system for impurity removal from a low-grade bauxite according to some embodiments of the disclosure, from another angle.
[0015] Corresponding relationships between reference symbols and component names is as follows: 100, crushing unit; 101, crusher; 102, rod mill; 200, pretreatment and classification unit; 201, storage tank; 203, raw material slurry pump; 204, 3 mm linear screen; 205, ore washing equipment; 206, 0.5 mm classification linear screen; 207, high-frequency rotary vibrating screen; 300, first gravity separation unit; 301, first dense medium mixing barrel; 302, first slurry pump; 303, first dense medium cyclone; 3031, underflow port; 3032, overflow port; 3033, central overflow pipe; 304, first dual-channel medium draining and washing screen; A, medium draining zone; B, medium washing zone; C, dewatering zone; 3041, medium draining discharge port; 3042, medium washing discharge port; 3043, partition plate; 3044, overflow feed port; 3045, underflow feed port; 3046, overflow discharge port; 3047, underflow discharge port; 3048, spray pipe; 305, second dense medium mixing barrel; 306, second slurry pump; 307, second dense medium cyclone; 308, second dual-channel medium draining and washing screen; 400, second gravity separation unit; 401, feeding mixing barrel; 402, double-drum centrifugal concentrator; 4021, first drum body; 4022, second drum body; 403, automatic control cabinet; 404, second size fraction tailing mixing barrel; 405, second size fraction tailing slurry pump; 406, second size fraction concentrate mixing barrel; 407, second size fraction concentrate slurry pump; 408, barrel pump; 500, dense medium recovery and reuse unit; 501, first magnetic separator; 502, second magnetic separator; 600, sedimentation and filter press unit; 601, second size fraction gravity separation tailing settling tank; 602, second size fraction gravity separation concentrate settling tank, DETAILED DESCRIPTION
[0016] In order to better understand the above technical solution, the technical solution of the embodiments of the disclosure will be described in detail below with reference to the drawings and specific embodiments. It should be understood that the embodiments of the disclosure and the specific features in the embodiments are detailed descriptions of the technical solution of the embodiments of the disclosure, rather than limitations on the technical solution of the disclosure. In the absence of conflict, the embodiments of the disclosure and the technical features in the embodiments may be combined with each other.
[0017] As shown in FIG. 1 to FIG. 7, according to an embodiment of the disclosure, a gravity separation beneficiation system for impurity removal from a low-grade bauxite is proposed, including: a crushing unit 100, configured to crush a raw material to obtain a crushed material; a pretreatment and classification unit 200, configured to pretreat the crushed material, and classify the crushed material after being pretreated according to a preset dimension to obtain a first size fraction material and a second size fraction material, where a particle size of the first size fraction material is greater than a particle size of the second size fraction material; a first gravity separation unit 300, configured to perform a gravity separation for impurity removal on the first size fraction material to obtain a first size fraction gravity separation concentrate and a first size fraction gravity separation tailing; a second gravity separation unit 400, configured to perform a gravity separation for impurity removal on the second size fraction material to obtain a second size fraction gravity separation concentrate and a second size fraction gravity separation tailing; and a sedimentation and filter press unit 600, configured to sediment and pressure filter the second size fraction gravity separation concentrate and the second size fraction gravity separation tailing to obtain a dewatered second size fraction product.
[0018] It can be understood that the gravity separation beneficiation system for impurity removal from the low-grade bauxite provided by the embodiments of the disclosure includes a crushing unit 100, a pretreatment and classification unit 200, a first gravity separation unit 300, a second gravity separation unit 400, and a sedimentation and filter press unit 600. The crushing unit 100 is configured to crush a raw material to obtain a crushed material. Subsequently, after the crushed material is washed and pretreated by the pretreatment and classification unit 200, the crushed material after being pretreated is classified according to a preset dimension to obtain a first size fraction material and a second size fraction material. A particle size of the first size fraction material is greater than a particle size of the second size fraction material. The first gravity separation unit 300 performs a gravity separation for impurity removal on the first size fraction material to obtain a first size fraction gravity separation concentrate and a first size fraction gravity separation tailing. The second gravity separation unit 400 performs a gravity separation for impurity removal on the second size fraction material to obtain a second size fraction gravity separation concentrate and a second size fraction gravity separation tailing. The sedimentation and filter press unit 600 performs a settling and pressure filtration operation on the second size fraction gravity separation concentrate and the second size fraction gravity separation tailing to obtain a dewatered second size fraction product. Compared with a flotation technology, in the gravity separation beneficiation system for impurity removal from the low-grade bauxite, slurry conditioning operations and reagent addition flotation operations are not required, and no chemical reagents are added throughout the gravity separation for impurity removal process. Meanwhile, there is no need to perform operations for removing the chemical reagents from the obtained first size fraction gravity separation concentrate, the first size fraction gravity separation tailing, the second size fraction gravity separation concentrate, and the second size fraction gravity separation tailing. Therefore, a operating cost is low and a process is simple. The dewatered second size fraction product includes the dewatered second size fraction gravity separation concentrate and the dewatered second size fraction gravity separation tailing. The dewatered first size fraction gravity separation tailing and the dewatered second size fraction gravity separation concentrate are aluminum concentrates with a high aluminum-silicon ratio and a low impurity content, have a high quality, and are suitable for manufacturing alumina, and thus are capable of improving a quality of an alumina product. The dewatered second size fraction gravity separation tailing has a high silicon dioxide content and is capable of being used as a material product in a building materials industry, eliminating requirements for harmless treatment or stockpile disposal of a tailing as required in a flotation technology, so that a utilization efficiency is improved, thereby reducing a treatment cost, and thus increasing a profit.
[0019] It should be noted that the raw material is a low-grade bauxite.
[0020] It should be noted that a low-grade bauxite is a type of bauxite resource having an aluminum-silicon ratio of less than 4, and thus the low-grade bauxite cannot be directly used for producing alumina by a Bayer process, and is even difficult to upgrade through conventional mineral processing methods.
[0021] It should be noted that the low-grade bauxite has an alumina content ranging from 50 % to 55 %, a silica content of more than 20 %. In the low-grade bauxite, an illite content is more than 20 %, and an aluminum-silicon ratio ranges from 2.0 to 2.75. In some embodiments, the selected low-grade bauxite has an alumina content of 53.56 %, a silica content of 21.36%. In the low-grade bauxite, an illite content is 23%, and an aluminum-silicon ratio is 2.50.
[0022] It can be understood that the pretreatment and classification unit 200 may be provided with a storage tank 201, a raw material slurry pump 203, a 3 mm linear screen 204, an ore washing equipment 205, a 0.5 mm classification linear screen 206, and a high-frequency rotary vibrating screen 207. The raw material, after being crushed by the crushing unit 100, may be placed into the storage tank 201. The crushed material is pumped by the raw material slurry pump 203 into the 3 mm linear screen 204 for classification. An oversize material (that is, an ore material on the screen, hereinafter referred to as "oversize material") of the 3 mm linear screen 204 has a relatively large particle size and needs to be returned to the crushing unit 100 for further treatment. An undersize material (that, an ore material passing through the screen, hereinafter referred to as "undersize material") of the 3 mm linear screen 204 enters the ore washing equipment 205 for washing. The washed undersize material then enters the 0.5 mm classification linear screen 206 for classification. A crushed material with a particle size ranging from -3 mm to +0.5 mm, that is, the crushed material with a particle size of less than 3 mm and greater than 0.5 mm, enters the first gravity separation unit 300. A crushed material with a particle size of less than 0.5 mm enters the high-frequency rotary vibrating screen 207 for classification. A crushed material with a particle size ranging from -5 mm to +0.15 mm is ground again by the rod mill 102, and a crushed material with a particle size of -0.15 mm, i.e., a crushed material with a particle size of less than 0.15 mm, enters the second gravity separation unit 400.
[0023] It should be noted that the sedimentation and filter press unit 600 may send the second size fraction gravity separation concentrate into a second size fraction gravity separation concentrate settling tank 602, and send the second size fraction gravity separation tailing into a second size fraction gravity separation tailing settling tank 601, and the materials, after settled for a period of time, are fed into a plate and frame filter press to be pressed into a filter cake.
[0024] In some examples, as shown in FIG. 1 and FIG. 2, the gravity separation beneficiation system for impurity removal from the low-grade bauxite also includes: a dense medium recovery and reuse unit 500, configured to process products obtained after the gravity separation for impurity removal is performed on the first size fraction material to obtain a dense medium, and configured to recover and reuse the dense medium. The products are the first size fraction gravity separation concentrate and the first size fraction gravity separation tailing.
[0025] It can be understood that, when the first gravity separation unit 300 performs the gravity separation for impurity removal separation operation on the first size fraction material, a dense medium is required. The dense medium may be a suspension prepared from water, a ferrosilicon powder, and a magnetite powder. A density of the suspension may be determined according to a process flow. The dense medium recovery and reuse unit 500 may be provided with a dense medium recovery magnetic separator. After the first gravity separation unit 300 performs a medium draining and washing process on the products, the drained and washed medium may be recovered by the dense medium recovery magnetic separator for reusing or sending back to a dense medium mixing barrel of the first gravity separation unit 300 for use. Therefore, product damage is reduced and costs are saved. The aforementioned products are the first size fraction gravity separation concentrate and the first size fraction gravity separation tailing obtained after the gravity separation for impurity removal is performed on the first size fraction material by the first gravity separation unit 300.
[0026] In some examples, as shown in FIG. 2, the crushing unit 100 includes: a crusher 101, which may be a jaw crusher and / or a cone crusher; and a rod mill 102. A discharge port of the rod mill 102 is a peripheral discharge port at an end head. Rods of the rod mill 102 occupy 1 / 4 to 1 / 2 of an internal volume of the rod mill 102. A liquid-to-solid ratio of a liquid inside the rod mill 102 to the raw material ranges from 0.4 to 0.65. The crushed material processed by the rod mill 102 has a particle size of -3 mm, and the crushed material having a particle size ranging from -3 mm to +0.5 mm accounts for 50% to 65% of the crushed material.
[0027] It can be understood that the crushing unit 100 may be provided with the crusher 101 and the rod mill 102 to progressively reduce the particle size of the crushed material. The crushed material finally processed by the rod mill 102 is an ore material having a particle size of -3 mm, and the crushed material having a particle size ranging from -3 mm to +0.5 mm accounts for 50% to 65% of the crushed material.
[0028] It should be noted that a specific value of a maximum crushed particle size of the crushed material may be determined based on basic properties of the selected crushed material and through process mineralogy research. The value of the maximum crushed particle size directly affects an efficiency of a gravity separation. By determining the maximum crushed particle size of the crushed material, the number of steel rods in the rod mill 102 and the liquid-to-solid ratio can be adjusted.
[0029] In some embodiments, the maximum crushed particle size of the crushed material is 3 mm, a volume of the steel rods is 2 / 5 of the internal volume of the rod mill 102, and the liquid-to-solid ratio is 0.55. In this crushed material, the crushed material having a particle size ranging from -3 mm to +0.5 mm accounts for 60%.
[0030] In some examples, the first size fraction material after being processed by the pretreatment and classification unit 200 has a particle size ranging from -n mm to +0.5 mm. n is a maximum particle size of the first size fraction material, and ranges from 1 mm to 4 mm. The second size fraction material after being processed by the pretreatment and classification unit 200 has a particle size of -0.15 mm. The crushed material with a particle size ranging from -0.5 mm to +0.15 mm after being processed by the pretreatment and classification unit 200 is returned to the rod mill 102 for further grinding, so as to improve a classification accuracy of the first size fraction material and the second size fraction material. Thus, misclassification is avoided and waste of the low-grade bauxite is reduced.
[0031] In some embodiments, n may be 3, the first size fraction material has a particle size ranging from -3 mm to +0.5 mm and accounts for 60%. The second size fraction material has a particle size of -0.15 mm and accounts for 40%.
[0032] In some examples, as shown in FIG. 1 to FIG. 3, the first gravity separation unit 300 includes: a first gravity separation impurity removal assembly and a second gravity separation impurity removal assembly. A primary gravity separation for impurity removal is performed on the first size fraction material by the first gravity separation impurity removal assembly to obtain a primary gravity separation concentrate and the first size fraction gravity separation tailing. A secondary gravity separation for impurity removal is performed on the primary gravity separation concentrate by the second gravity separation impurity removal assembly to obtain the first size fraction gravity separation concentrate and a secondary gravity separation tailing. The secondary gravity separation tailing is returned to the first gravity separation impurity removal assembly for the gravity separation for impurity removal again.
[0033] It can be understood that the first gravity separation unit 300 may be provided with the first gravity separation impurity removal assembly and the second gravity separation impurity removal assembly, and a particle size screened by the first gravity separation unit 300 is larger than a particle size screened by the second gravity separation unit 400. The first size fraction material separated by the pretreatment and classification unit 200 may first pass through the first gravity separation impurity removal assembly to be subjected to the primary gravity separation for impurity removal separation, thereby obtaining the primary gravity separation concentrate and the first size fraction gravity separation tailing, so as to implement a roughing process. After the roughing is completed, the secondary gravity separation for impurity removal is performed on the primary gravity separation concentrate by the second gravity separation impurity removal assembly to obtain the first size fraction gravity separation concentrate and the secondary gravity separation tailing, and the secondary gravity separation tailing are re-fed into the first gravity separation impurity removal assembly for further treatment. Through the roughing and cleaning process flows, a grade and a recovery rate of the first size fraction concentrate can be ensured, and thus a utilization rate of the low-grade bauxite is improved. Thus, the separation of the aluminum mineral and the impurity mineral can be better achieved.
[0034] In some examples, for an operation of the primary gravity separation for impurity removal by the first gravity separation impurity removal assembly, a separation density ranges from 1.5 g / cm3 to 1.9 g / cm3, and a feed pressure ranges from 0.08 MPa to 0.12 Mpa. For an operation of the secondary gravity separation for impurity removal operation by the second gravity separation impurity removal assembly, a separation density ranges from 2.0 g / cm3 to 2.9 g / cm3, and a feed pressure ranges from 0.14 MPa to 0.2 MPa.
[0035] It can be understood that the separation density of the primary gravity separation for impurity removal operation is less than the separation density of the secondary gravity separation for impurity removal operation of the second gravity separation impurity removal assembly, and the feed pressure of the primary gravity separation for impurity removal operation is less than the feed pressure of the secondary gravity separation for impurity removal operation. The separation density and the feed pressure are set as described above, so that the roughing and cleaning process flows can be achieved, thereby ensuring the grade and the recovery rate of the first size fraction concentrate, and improving the utilization rate of the low-grade bauxite. Thus, the separation of the aluminum mineral and the impurity mineral can be better achieved.
[0036] In some embodiments, the primary gravity separation for impurity removal operation has a separation density of 1.85 g / cm3 and a feed pressure of 0.1 MPa. The secondary gravity separation impurity removal operation has a separation density of 2.0 g / cm3 and a feed pressure of 0.16 MPa.
[0037] In some examples, as shown in FIG. 2 to FIG. 5, the first gravity separation impurity removal assembly includes: a first dense medium mixing barrel 301, a first slurry pump 302, a first dense medium cyclone 303, and a first dual-channel medium draining and washing screen 304. The second gravity separation impurity removal assembly includes: a second dense medium mixing barrel 305, a second slurry pump 306, a second dense medium cyclone 307, and a second dual-channel medium draining and washing screen 308. During the primary gravity separation for impurity removal operation, the first size fraction material enters the first dense medium mixing barrel 301, and is pumped by the first slurry pump 302 into the first dense medium cyclone 303. After an overflow and an underflow of the first dense medium cyclone 303 are separated from the dense medium by the first dual-channel medium draining and washing screen 304, an overflow oversize material which remains on the first dense medium cyclone 303 is the first size fraction gravity separation tailing, and an underflow oversize material which remains on the first dense medium cyclone 303 is the primary gravity separation concentrate. During the secondary gravity separation for impurity removal operation, the primary gravity separation concentrate enters the second dense medium mixing barrel 305, and is pumped by the second slurry pump 306 into the second dense medium cyclone 307. After an overflow and an underflow of the second dense medium cyclone 307 are separated from the dense medium by the second dual-channel medium draining and washing screen 308, an underflow oversize material which remains on the second dense medium cyclone 307 is the first size fraction gravity separation concentrate, and an overflow oversize material which remains on the second dense medium cyclone 307 is the secondary gravity separation tailing. The secondary gravity separation tailing is returned to the first dense medium mixing barrel 301 to repeat a process of the primary gravity separation for impurity removal operation.
[0038] It can be understood that the first gravity separation impurity removal assembly may be provided with the first dense medium mixing barrel 301, the first slurry pump 302, the first dense medium cyclone 303, and the first dual-channel medium draining and washing screen 304. When the primary gravity separation for impurity removal operation is performed, a first dense medium suspension may be prepared first. Then, the first size fraction material is fed into the first dense medium mixing barrel 301, and is pumped by the first slurry pump 302 into the first dense medium cyclone 303. A screening operation is performed by the first dense medium cyclone 303, and the first dense medium cyclone 303 is connected to the first dual-channel medium draining and washing screen 304. The overflow of the first dense medium cyclone 303 enters the first dual-channel medium draining and washing screen 304 through an overflow feed port 3044. The underflow of the first dense medium cyclone 303 enters the first dual-channel medium draining and washing screen 304 through an underflow feed port 3045, and then a medium draining and washing operation is performed by the first dual-channel medium draining and washing screen 304. An overflow oversize material, after the medium draining and washing operation is completed, is discharged through an overflow discharge port 3046, and the processed overflow oversize material is the first size fraction gravity separation tailing. An underflow oversize material, after the medium draining and washing operation is completed, is discharged through an underflow discharge port 3047, and the processed underflow oversize material remaining on the first dense medium cyclone 303 is the primary gravity separation concentrate, thereby achieving a coarse screening operation on the first size fraction material.
[0039] It can be understood that the second gravity separation impurity removal assembly may be provided with the second dense medium mixing barrel 305, the second slurry pump 306, the second dense medium cyclone 307, and the second dual-channel medium draining and washing screen 308. When the secondary gravity separation for impurity removal operation is performed, a second dense medium suspension may be prepared first. Then, the primary gravity separation concentrate is fed into the second dense medium mixing barrel 305, and is pumped by the second slurry pump 306 into the second dense medium cyclone 307. A screening operation is performed by the second dense medium cyclone 307, and the second dense medium cyclone 307 is connected to the second dual-channel medium draining and washing screen 308. The overflow and the underflow of the second dense medium cyclone 307 are respectively subjected to the medium draining and washing operation by the second dual-channel medium draining and washing screen 308. A processed overflow oversize material is the secondary gravity separation tailing, and an underflow oversize material remaining on the second dense medium cyclone 303 is the first size fraction gravity separation concentrate, thereby achieving a fine screening operation on the first size fraction material. The secondary gravity separation tailing needs to be re-fed into the first gravity separation impurity removal assembly for a coarse screening operation, and then fed into the second gravity separation impurity removal assembly for the fine screening operation, so as to ensure the grade and the recovery rate of the first size fraction concentrate, and improve the utilization rate of the low-grade bauxite. Thus, the separation of the aluminum mineral and the impurity mineral can be better achieved.
[0040] It should be noted that a density of the first dense medium suspension is less than a density of the second dense medium suspension.
[0041] It should be noted that, as shown in FIG. 4 and FIG. 5, the first dual-channel medium draining and washing screen 304 is provided with two under-screen discharge ports, namely, a medium draining discharge port 3041 and a medium washing discharge port 3042. A suspension flowing out from the medium draining discharge port 3041 may be directly returned to the dense medium mixing barrel. A material flowing out from the medium washing discharge port 3042 is the dense medium and water. The dense medium is the dense medium removed from a product by spraying, and then the dense medium flows into a dense medium recovery magnetic separator for recovering the dense medium and is returned to the dense medium mixing barrel for reuse. A screen surface is provided with a partition plate 3043, and a position of the partition plate 3043 may be adjusted according to basic properties of an ore. Moreover, the first dual-channel medium draining and washing screen 304 and the second dual-channel medium draining and washing screen 308 may adopt the same structure.
[0042] As shown in FIG. 4, in some embodiments, a length of a screen surface of the dual-channel medium draining and washing screen is 4 m. The screen surface of the dual-channel medium draining and washing screen is divided into: a medium draining zone A from a feed end to 2 m, a medium washing zone B from 2 m to 3.5 m, with a plurality of spray pipes 3048 added above the medium washing zone B (the specific number thereof may be determined according to an on-site effect), and a dewatering zone C from 3.5 m to 4 m.
[0043] In some examples, the first dense medium cyclone 303 and the second dense medium cyclone 307 form a two-stage series dense medium cyclone. An included angle between the two-stage series dense medium cyclone and the horizontal plane ranges from 15° to 20°. A cone angle of the two-stage series dense medium cyclone ranges from 20° to 40°. A diameter of an underflow port 3031 of the two-stage series dense medium cyclone ranges from 20 mm to 30 mm. A diameter of the overflow port 3032 of the two-stage series dense medium cyclone ranges from 60 mm to 70 mm. A length of a central overflow pipe 3033 of the two-stage series dense medium cyclone ranges from 300 mm to 450 mm. The diameter of the underflow port 3031 of the second dense medium cyclone 307 is less than the diameter of the underflow port 3031 of the first dense medium cyclone 303.
[0044] It can be understood that the first dense medium cyclone 303 and the second dense medium cyclone 307 may constitute a two-stage series dense medium cyclone, so that the underflow oversize material of the first dense medium cyclone 303, that is, the primary gravity separation concentrate can be quickly fed into the second dense medium cyclone 307, thereby shortening a process route and improving an efficiency. Moreover, both the first dense medium cyclone 303 and the second dense medium cyclone 307 form an included angle with the horizontal plane to achieve a better separation effect. The diameters of the overflow ports 3032 and the lengths of the central overflow pipes 3033 of the first dense medium cyclone 303 and the second dense medium cyclone 307 may adopt the same parameters, and the diameter of the underflow port 3031 of the second dense medium cyclone 307 is less than the diameter of the underflow port 3031 of the first dense medium cyclone 303, so as to ensure that the second dense medium cyclone 307 has a higher screening accuracy, thereby ensuring a grade of the first size fraction concentrate.
[0045] In some embodiments, as shown in FIG. 3, the included angle between the first dense medium cyclone 303 and the horizontal plane is 20°, the diameter of the underflow port 3031 is 25 mm, the diameter of the overflow port 3032 is 60 mm, and the length of the central overflow pipe 3033 is 400 mm.
[0046] In some examples, as shown in FIG. 6 and FIG. 7, the second gravity separation unit 400 includes: a double-drum centrifugal concentrator 402. The double-drum centrifugal concentrator 402 is provided with a first drum body 4021 and a second drum body 4022. An inclination angle of a sloped surface of the first drum body 4021 and an inclination angle of a sloped surface of the second drum body 4022 range from 2° to 8°. The first drum body 4021 is configured to perform a primary centrifugal impurity removal on the second size fraction material to obtain a primary impurity removal tailing and a primary impurity removal concentrate. The second drum body 4022 is configured to perform a secondary centrifugal impurity removal on the primary impurity removal tailing to obtain the second size fraction gravity separation tailing and a secondary impurity removal concentrate. The primary impurity removal concentrate and the secondary impurity removal concentrate are mixed to form the second size fraction gravity separation concentrate. A diameter of the first drum body 4021 is less than a diameter of the second drum body 4022.
[0047] It can be understood that the second gravity separation unit 400 is provided with a feeding mixing barrel 401, the double-drum centrifugal concentrator 402, a second size fraction tailing mixing barrel 404, a second size fraction tailing slurry pump 405, a second size fraction concentrate mixing barrel 406, a second size fraction concentrate slurry pump, and a barrel pump 408. The second size fraction material may be pumped by the barrel pump 408 into the feeding mixing barrel 401, and then flows by gravity into the double-drum centrifugal concentrator 402. The second size fraction material first flows into the first drum body 4021 for a primary centrifugal impurity removal. The primary centrifugal impurity removal tailing flows with water into the second drum body 4022 for a secondary centrifugal impurity removal. The secondary centrifugal impurity removal tailing directly flows out as a second size fraction centrifugal tailing. After a feed is stopped, a flushing water is turned on to flush out a primary centrifugal concentrate attached to a side wall of the first drum body 4021 and a secondary centrifugal concentrate attached to a side wall of the second drum body 4022, which are combined to form a second size fraction centrifugal concentrate. The second size fraction centrifugal tailing flows into the second size fraction tailing mixing barrel 404, and a slurry is pumped by the second size fraction tailing slurry pump 405 into the sedimentation and filter press unit 600 for settling and pressure filtration. The second size fraction centrifugal concentrate flows into the second size fraction concentrate mixing barrel 406, and a slurry is pumped by the second size fraction concentrate slurry pump into the sedimentation and filter press unit 600 for settling and pressure filtration.
[0048] It should be noted that the inclination angle of the sloped surface of the first drum body 4021 and the inclination angle of the sloped surface of the second drum body 4022 range from 2° to 8°, and the inclination angle of the first drum body 4021 is greater than the inclination angle of the sloped surface of the second drum body 4022. In some embodiments, the inclination angle of the first drum body 4021 is 6°, and the inclination angle of the sloped surface of the second drum body 4022 is 2°.
[0049] It can be understood that the double-drum centrifugal concentrator 402 may also be provided with a feed port, a discharge port, a flushing water pipe, a rinsing water pipe, and an automatic control cabinet 403. The automatic control cabinet 403 may be used to control a drum frequency of the first drum body 4021 and a drum frequency of the second drum body 4022, and a range of the drum frequencies is controlled to range from 20 Hz to 40 Hz. An amount of rinsing water is controlled to range from 300 L / h to 500 L / h. An automation program is provided in the automatic control cabinet, and is divided into an initial stage, a feeding stage, an ore cutoff stage, a rinsing stage, and an ending stage. An operation time may be set for each stage. The initial stage occurs only once each time the machine is started, and then the sequence cycles in order. The set drum frequencies and the amount of the rinsing water can directly affect a gravity separation for impurity removal effect of the centrifugal concentrator. A setting of a time for each stage can increase a throughput of the equipment without affecting the gravity separation effect. The feed port and the discharge port are connected to a cylinder, an air pump, and an air compressor to achieve an automatic control. In some implementations, when entering the feeding stage, a material inlet will swing toward a feed inlet, and the discharge port will swing toward a tailing discharge port. The second size fraction material will flow into the centrifugal concentrator for separation, and the second size fraction gravity separation tailing will flow out immediately. When entering the ore cutoff stage, the material inlet will swing toward a circulation return port, and a material is pumped back into the feeding mixing barrel 401 by the barrel pump 408 for circulation. After a preset time, the drum frequencies automatically decrease to be 10 Hz. When entering the rinsing stage, the discharge port will quickly swing toward a concentrate discharge port, and a flushing water solenoid valve opens. When the system enters the ending stage, the drum frequencies automatically increase to set values. A feeding mode is a gravity flow feeding, and a feed amount may be controlled by adjusting a size of a valve opening.
[0050] In some embodiments, the automatic control cabinet 403 may control the drum frequencies of the first drum body 4021 and the second drum body 4022 to be 30 Hz, and control the amount of the rinsing water to be 400 L / h. Set times for the five stages of the automation program are 10 s, 30 s, 6 s, 10 s, and 5 s, respectively.
[0051] In some examples, the dense medium used by the first gravity separation unit 300 includes a ferrosilicon powder and a magnetite powder. A ratio of the ferrosilicon powder to the magnetite powder is 1:3. Particle sizes of the ferrosilicon powder and the magnetite powder each are less than 0.038 mm.
[0052] It can be understood that the dense medium recovery magnetic separator may be provided with a first magnetic separator 501 and a second magnetic separator 502. The first magnetic separator 501 is used for recover the dense medium from the primary gravity separation concentrate and the first size fraction gravity separation tailing. The second magnetic separator 502 is used to recover the dense medium from the first size fraction gravity separation concentrate and the secondary gravity separation tailing.
[0053] In some embodiments, when the selected low-grade bauxite has an alumina content of 53.56%, a silica content of 21.36%, an illite content of 23%, and an aluminum-silicon ratio of 2.50. By using the above exemplary parameters, a first size fraction concentrate with a yield of 40.10%, an alumina content of 66.65%, and an aluminum-silicon ratio of 7.61 is obtained; and a second size fraction concentrate with a yield of 11.15%, an alumina content of 59.36%, and an aluminum-silicon ratio of 5.31 is obtained. Thus, an efficient utilization of the low-grade bauxite is achieved. The experimental results are shown in Table 1, where A / S represents the aluminum-silicon ratio.
[0054] Table 1 Test results of Example 1 Product Yield / % Al2O3 / % SiO2 / % Fe2O3 / % A / S Coarse concentrate 40.10 66.65 8.76 7.61 7.61 Coarse tailing 33.08 38.50 33.15 1.16 1.16 Fine concentrate 11.15 59.36 11.19 4.85 5.31 Fine tailing 15.67 35.48 28.72 1.23 1.24 Low-grade bauxite 100.00 51.64 20.23 4.17 2.55
[0055] Compared with the related art, the disclosure includes at least the following beneficial effects: the gravity separation beneficiation system for impurity removal from the low-grade bauxite provided by the embodiments of the disclosure includes a crushing unit, a pretreatment and classification unit, a first gravity separation unit, a second gravity separation unit, and a sedimentation and filter press unit. The crushing unit is configured to crush a raw material to obtain a crushed material. Subsequently, after the crushed material is washed and pretreated by the pretreatment and classification unit, the crushed material after being pretreated is classified according to a preset dimension to obtain a first size fraction material and a second size fraction material. A particle size of the first size fraction material is greater than a particle size of the second size fraction material. The first gravity separation unit performs a gravity separation for impurity removal on the first size fraction material to obtain a first size fraction gravity separation concentrate and a first size fraction gravity separation tailing; the second gravity separation unit performs a gravity separation for impurity removal on the second size fraction material to obtain a second size fraction gravity separation concentrate and a second size fraction gravity separation tailing. The sedimentation and filter press unit performs a settling and pressure filtration operation on the second size fraction gravity separation concentrate and the second size fraction gravity separation tailing to obtain a dewatered second size fraction product. Compared with a flotation technology, in the gravity separation beneficiation system for impurity removal from the low-grade bauxite, slurry conditioning operations and reagent addition flotation operations are not required, and no chemical reagents are added throughout the gravity separation for impurity removal process. Meanwhile, there is no need to perform operations for removing the chemical reagents from the obtained first size fraction gravity separation concentrate, the first size fraction gravity separation tailing, the second size fraction gravity separation concentrate, and the second size fraction gravity separation tailing. Therefore, a operating cost is low and a process is simple. The dewatered second size fraction product includes the dewatered second size fraction gravity separation concentrate and the dewatered second size fraction gravity separation tailing. The dewatered first size fraction gravity separation tailing and the dewatered second size fraction gravity separation concentrate are aluminum concentrates with a high aluminum-silicon ratio and a low impurity content, have a high quality, and are suitable for manufacturing alumina, and thus are capable of improving a quality of an alumina product. The dewatered second size fraction gravity separation tailing has a high silicon dioxide content and is capable of being used as a material product in a building materials industry, eliminating requirements for harmless treatment or stockpile disposal of a tailing as required in a flotation technology, so that a utilization efficiency is improved, thereby reducing a treatment cost, and thus increasing a profit.
[0056] In the disclosure, the terms "first", "second", "third" are used for descriptive purposes only, and shall not be construed as indicating or implying relative importance. The term "plurality" means two or more, unless otherwise explicitly defined. The terms "mounting", "connected", "connection", "fixing" and the like shall be interpreted broadly. For example, the "connected" may mean a fixed connection, a detachable connection, or an integral connection; the " connection " may mean a direct connection or an indirect connection via an intermediate medium. A person with ordinary skill in the art may understand the specific meanings of the above terms in the disclosure according to the specific circumstances.
[0057] In the description of the disclosure, it should be understood that the terms “upper”, “lower”, “left”, “right”, “front”, “rear”, or the like, indicating orientation or positional relationships based on the orientation or positional relationships shown in the drawings, are merely for the convenience of describing the disclosure and simplifying the description, and do not indicate or imply that the referred device or unit must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they shall not be construed as limitations on the disclosure.
[0058] In the description of this specification, the terms “one embodiment”, “some embodiments”, “specific embodiment” and the like are used for indicating that a particular feature, structure, material, or characteristic described in combination with the embodiment or example is included in at least one embodiment or example of the disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
[0059] The above are only preferred embodiments of the disclosure, and are not intended to limit the disclosure. Various modifications and changes may be made to the disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, or the like, made within the spirit and principles of the disclosure shall be included within the protection scope of the disclosure.
Claims
1. A gravity separation beneficiation system for impurity removal from a low-grade bauxite, comprising:a crushing unit, configured to crush a raw material to obtain a crushed material;a pretreatment and classification unit, configured to pretreat the crushed material and classify the crushed material after being pretreated according to a preset dimension to obtain a first size fraction material and a second size fraction material, wherein a particle size of the first size fraction material is greater than a particle size of the second size fraction material;a first gravity separation unit, configured to perform a gravity separation for impurity removal on the first size fraction material to obtain a first size fraction gravity separation concentrate and a first size fraction gravity separation tailing;a second gravity separation unit, configured to perform a gravity separation for impurity removal on the second size fraction material to obtain a second size fraction gravity separation concentrate and a second size fraction gravity separation tailing; anda sedimentation and filter press unit, configured to sediment and pressure filter the second size fraction gravity separation concentrate and the second size fraction gravity separation tailing to obtain a dewatered second size fraction product.
2. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 1, further comprising:a dense medium recovery and reuse unit, configured to process products obtained after the gravity separation for impurity removal is performed on the first size fraction material, to obtain a dense medium, and configured to recover and reuse the dense medium;wherein the products are the first size fraction gravity separation concentrate and the first size fraction gravity separation tailing.
3. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 1, wherein the crushing unit comprises a crusher and a rod mill, wherein,a discharge port of the rod mill is a peripheral discharge port at an end head, and rods of the rod mill occupy 1 / 4 to 1 / 2 of an internal volume of the rod mill;a liquid-to-solid ratio of a liquid inside the rod mill to the raw material ranges from 0.4 to 0.65; andthe crushed material processed by the rod mill has a particle size of -3 mm, and the crushed material having a particle size ranging from -3 mm to +0.5 mm accounts for 50% to 65% of the crushed material.
4. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 3, wherein,the first size fraction material, after being processed by the pretreatment and classification unit, has a particle size ranging from -n mm to +0.5 mm, wherein n is a maximum particle size of the first size fraction material, and ranges from 1 mm to 4 mm;the second size fraction material, after being processed by the pretreatment and classification unit, has a particle size of -0.15 mm; andthe crushed material with the particle size ranging from -0.5 mm to +0.15 mm, after being processed by the pretreatment and classification unit, is returned to the rod mill for further grinding.
5. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 2, wherein the first gravity separation unit comprises a first gravity separation impurity removal assembly and a second gravity separation impurity removal assembly, wherein,a primary gravity separation for impurity removal is performed on the first size fraction material by the first gravity separation impurity removal assembly to obtain a primary gravity separation concentrate and the first size fraction gravity separation tailing; anda secondary gravity separation for impurity removal is performed on the primary gravity separation concentrate by the second gravity separation impurity removal assembly to obtain the first size fraction gravity separation concentrate and a secondary gravity separation tailing, the secondary gravity separation tailing being returned to the first gravity separation impurity removal assembly for the gravity separation for impurity removal again.
6. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 5, wherein,for an operation of the primary gravity separation for impurity removal by the first gravity separation impurity removal assembly, a separation density ranges from 1.5 g / cm3 to 1.9 g / cm3, a feed pressure ranging from 0.08 MPa to 0.12 MPa; andfor an operation of the secondary gravity separation for impurity removal by the second gravity separation impurity removal assembly, a separation density ranges from 2.0 g / cm3 to 2.9 g / cm3, a feed pressure ranging from 0.14 MPa to 0.2 MPa.
7. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 6, wherein the first gravity separation impurity removal assembly comprises: a first dense medium mixing barrel, a first slurry pump, a first dense medium cyclone, and a first dual-channel medium draining and washing screen, and wherein the second gravity separation impurity removal assembly comprises: a second dense medium mixing barrel, a second slurry pump, a second dense medium cyclone, and a second dual-channelmedium draining and washing screen;during the operation of the primary gravity separation for impurity removal, the first size fraction material enters the first dense medium mixing barrel, and is pumped by the first slurry pump into the first dense medium cyclone; after an overflow and an underflow of the first dense medium cyclone are separated from the dense medium by the first dual-channel medium draining and washing screen, an overflow oversize material which remains on the first dense medium cyclone is the first size fraction gravity separation tailing, and an underflow oversize material which remains on the first dense medium cyclone is the primary gravity separation concentrate;during the operation of the secondary gravity separation for impurity removal , the primary gravity separation concentrate enters the second dense medium mixing barrel, and is pumped by the second slurry pump into the second dense medium cyclone; after an overflow and an underflow of the second dense medium cyclone are separated from the dense medium by the second dual-channel medium draining and washing screen, an underflow oversize material which remains on the second dense medium cyclone is the first size fraction gravity separation concentrate, and an overflow oversize material which remains on the second dense medium cyclone is the secondary gravity separation tailing, the secondary gravity separation tailing being returned to the first dense medium mixing barrel to repeat a process of the primary gravity separation for impurity removal operation.
8. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 7, wherein,the first dense medium cyclone and the second dense medium cyclone constitute a two-stage series dense medium cyclone, and an included angle between the two-stage series dense medium cyclone and a horizontal plane ranges from 15° to 20°; a cone angle of the two-stage series dense medium cyclone ranges from 20° to 40°; a diameter of an underflow port of the two-stage series dense medium cyclone ranges from 20 mm to 30 mm; a diameter of an overflow port of the two-stage series dense medium cyclone a diameter of 60 mm to 70 mm; and a length of a central overflow pipe of the two-stage series dense medium cyclone ranges from 300 mm to 450 mm;wherein the diameter of the underflow port of the second dense medium cyclone is less than the diameter of the underflow port of the first dense medium cyclone.
9. The gravity separation beneficiation system for impurity removal from the low-grade bauxite according to claim 1, wherein the second gravity separation unit comprises:a double-drum centrifugal concentrator provided with a first drum body and a second drum body, wherein an inclination angle of a sloped surface of the first drum body and an inclination angle of a sloped surface of the second drum body range from 2° to 8°, the firstdrum body being configured to perform a primary centrifugal impurity removal on the second size fraction material to obtain a primary impurity removal tailing and a primary impurity removal concentrate, the second drum body being configured to perform a secondary centrifugal impurity removal on the primary impurity removal tailing to obtain the second size5 fraction gravity separation tailing and a secondary impurity removal concentrate, wherein the primary impurity removal concentrate and the secondary impurity removal concentrate are mixed to form the second size fraction gravity separation concentrate;wherein a diameter of the first drum body is less than a diameter of the second drum body.
10. The gravity separation beneficiation system for impurity removal from the low-grade10 bauxite according to claim 7, wherein,a dense medium used by the first gravity separation unit comprises a ferrosilicon powder and a magnetite powder, a ratio of the ferrosilicon powder to the magnetite powder being 1:3, particle sizes of the ferrosilicon powder and the magnetite powder each being less than 0.038mm.