Reselection, impurity removal and mineral separation system for treating low-grade bauxite

Abstract

The embodiment of the invention discloses a reselection impurity removal mineral separation system for treating low-grade bauxite, which comprises a crushing unit for crushing raw materials to obtain crushed materials; the pre-treatment grading unit is used for pre-treating the crushed materials and carrying out grading treatment on the pre-treated crushed materials according to a preset size so as to obtain first-size-fraction materials and second-size-fraction materials, and the granularity of the first-size-fraction materials is larger than that of the second-size-fraction materials; the first gravity separation unit is used for carrying out gravity separation, impurity removal and separation on the first-size-fraction materials so as to obtain first-size-fraction gravity separation concentrate and first-size-fraction gravity separation tailings; the second gravity separation unit is used for carrying out gravity separation, impurity removal and separation on the second-size-fraction material to obtain second-size-fraction gravity separation concentrate and second-size-fraction gravity separation tailings; and the settling and filter-pressing unit is used for settling and filter-pressing the gravity concentrate of the second fraction to obtain a dehydrated product of the second fraction. By means of the arrangement, the aluminum concentrate with the high aluminum oxide content, the high aluminum-silicon ratio and the relatively low impurity content can be obtained, the tailings with the high silicon dioxide content can be obtained, the whole system has the advantages that the operation cost is low, the process is simple, no chemical agent is added in the whole reselection impurity removal process, the concentrate is suitable for producing aluminum oxide, and the tailings are applied to the building material industry. The method can effectively reduce the ore consumption of alumina production from low-grade bauxite and reduce the red mud amount.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of mineral processing, and in particular to a re-selection and impurity removal system for processing low-grade bauxite. Background Art

[0002] With the increasing depletion of high-grade bauxite resources, the aluminum-silicon ratio of alumina enterprises has dropped significantly. The bauxite impurity removal technologies that have been industrialized are mainly high-sulfur bauxite flotation desulfurization technology and low-quality bauxite flotation desiliconization technology. Flotation technology has the disadvantages of high cost, complex process, high energy consumption of ore fine grinding and dissociation, and difficulty in storage and disposal due to residual reagents, fine particle size and high water content in the tailings. As a result, alumina enterprises have a low profit margin in producing alumina using aluminum concentrate, which seriously limits the industrialization and promotion of bauxite flotation desiliconization technology. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] To this end, the present invention provides a re-selection and impurity removal ore dressing system for processing low-grade bauxite.

[0005] In view of this, according to an embodiment of the present application, a re-selection and impurity removal system for processing low-grade bauxite is proposed, comprising:

[0006] A crushing unit, used for crushing raw materials to obtain crushed materials;

[0007] A pretreatment and grading unit, used for pretreatment of the crushed material, and grading the crushed material after pretreatment according to a preset size to obtain a first-grade material and a second-grade material, wherein the particle size of the first-grade material is greater than that of the second-grade material;

[0008] The first gravity separation unit is used for gravity separation and impurity removal of the first particle size material to obtain the first particle size gravity separation concentrate and the first particle size gravity separation tailings;

[0009] The second gravity separation unit is used for gravity separation and impurity removal of the second size material to obtain the second size gravity separation concentrate and the second size gravity separation tailings;

[0010] The sedimentation and filtration unit is used for sedimentation and filtration of the second particle size gravity separation concentrate and the second particle size gravity separation tailings to obtain a dehydrated second particle size product.

[0011] In a feasible implementation, it also includes:

[0012] The medium recovery and reuse unit is used to obtain the medium by processing the product obtained after the first-grade material is re-selected, impurity-removed and separated, and to recover and reuse the above medium.

[0013] In a feasible embodiment, the above-mentioned crushing unit includes:

[0014] jaw crushers, cone crushers and rod mills;

[0015] Among them, the discharge port of the rod mill is the peripheral discharge of the end, and the rod body of the rod mill occupies 1 / 4 to 1 / 2 of the cavity volume of the rod mill; the liquid-to-solid ratio of the liquid in the cavity of the rod mill and the raw material is 0.4 to 0.65; the crushed material after being processed by the rod mill is ore with a particle size of -3mm, and the material with a particle size of -3+0.5mm accounts for 50% to 65% of the crushed material.

[0016] In a feasible implementation manner, the particle size of the first-grade material obtained after being processed by the pretreatment and classification unit is -n+0.5 mm, wherein n is the maximum particle size of the first-grade material, and the value range of n is 1 mm to 4 mm;

[0017] The particle size of the second-grade material obtained after being processed by the pretreatment and classification unit is -0.15 mm;

[0018] The material with a particle size of -0.5+0.15 mm obtained after being processed by the pretreatment and classification unit is returned to the rod mill for further grinding.

[0019] In a feasible implementation manner, the first reselection unit includes:

[0020] The first gravity separation impurity removal component and the second gravity separation impurity removal component, the first size material is subjected to a first gravity separation impurity removal separation by the first gravity separation impurity removal component to obtain a first gravity separation concentrate and a first size gravity separation tailings; the first gravity separation concentrate is subjected to a second gravity separation impurity removal separation by the second gravity separation impurity removal component to obtain the first size gravity separation concentrate and a second gravity separation tailings, and the second gravity separation tailings are returned to the first gravity separation impurity removal component for another gravity separation impurity removal.

[0021] In a feasible implementation manner, the separation density of the first gravity separation and impurity removal operation of the first gravity separation and impurity removal component is 1.5 g / cm 3 Up to 1.9 / cm 3 , the feeding pressure is 0.08Mpa to 0.12Mpa;

[0022] The separation density of the secondary gravity separation and impurity removal operation of the second gravity separation and impurity removal component is 2.0g / cm 3 Up to 2.9 / cm 3 , the feeding pressure is 0.14Mpa to 0.2Mpa.

[0023] In a feasible embodiment, the first gravity separation and impurity removal component comprises: a first heavy medium stirring barrel, a first slurry pump, a first heavy medium cyclone, and a first dual-channel medium removal and washing screen; the second gravity separation and impurity removal component comprises: a second heavy medium stirring barrel, a second slurry pump, a second heavy medium cyclone, and a second dual-channel medium removal and washing screen;

[0024] During the above-mentioned primary gravity separation and impurity removal operation, the above-mentioned first-grade material enters the above-mentioned first heavy medium stirring barrel, and is pumped into the above-mentioned first heavy medium cyclone through the above-mentioned first slurry pump. After the overflow and underflow of the above-mentioned first heavy medium cyclone pass through the above-mentioned first double-channel de-medium washing screen to separate the medium, the ore on the overflow screen of the above-mentioned first heavy medium cyclone is the above-mentioned first-grade gravity separation tailings, and the ore on the underflow screen of the above-mentioned first heavy medium cyclone is the above-mentioned primary gravity separation concentrate;

[0025] During the secondary gravity separation and impurity removal process, the primary gravity separation concentrate enters the second heavy medium stirring barrel, and is pumped into the second heavy medium cyclone through the second slurry pump. After the overflow and underflow of the second heavy medium cyclone pass through the second double-channel de-medium washing screen to separate the medium, the ore on the underflow screen of the second heavy medium cyclone is the first-grade gravity separation concentrate, and the ore on the overflow screen of the second heavy medium cyclone is the secondary gravity separation tailings, which return to the first heavy medium stirring barrel to repeat the primary gravity separation and impurity removal process.

[0026] In a feasible embodiment, the first heavy medium cyclone and the second heavy medium cyclone constitute a two-stage series heavy medium cyclone, the placement angle of the two-stage series heavy medium cyclone and the angle between the horizontal plane are 15° to 20°; the cone angle of the two-stage series heavy medium cyclone is 20° to 40°; the bottom flow port diameter of the two-stage series heavy medium cyclone is 20mm to 30mm; the overflow port diameter of the two-stage series heavy medium cyclone is 60mm to 70mm; the length of the central overflow pipe of the two-stage series heavy medium cyclone is 300mm to 450mm;

[0027] Wherein, the diameter of the underflow port of the second heavy medium cyclone is smaller than the diameter of the underflow port of the first heavy medium cyclone.

[0028] In a feasible implementation manner, the second reselection unit includes:

[0029] A double-drum centrifugal concentrator, wherein the double-drum centrifugal concentrator is provided with a first drum body and a second drum body, wherein the inclined surfaces of the first drum body and the second drum body have an inclination angle of 2° to 8°, wherein the first drum body is used to perform a primary centrifugal impurity removal on the second particle size to obtain a primary impurity-removed tailing and a primary impurity-removed concentrate; and the second drum body is used to perform a secondary centrifugal impurity removal on the primary impurity-removed tailing to obtain a second particle size gravity-removed tailing and a secondary impurity-removed concentrate, wherein the primary impurity-removed concentrate and the secondary impurity-removed concentrate are combined into a second particle size gravity-removed concentrate;

[0030] Wherein, the diameter of the first rotating drum body is smaller than the diameter of the second rotating drum body.

[0031] In a feasible implementation, the heavy medium used in the first gravity selection unit includes ferrosilicon powder and magnet powder, the ratio of the ferrosilicon powder to the magnet powder is 1:3, and the particle sizes of the ferrosilicon powder and the magnet powder are both less than 0.038 mm.

[0032] Compared with the prior art, the present invention at least includes the following beneficial effects: the re-selection and impurity removal ore dressing system for processing low-grade bauxite provided in the embodiment of the present application includes a crushing unit, a pre-treatment classification unit, a first re-selection unit, a second re-selection unit and a sedimentation filter press unit. Among them, the crushing unit is used to crush the raw material to obtain the crushed material, and then the crushed material is cleaned and pre-treated by the pre-treatment classification unit, and the pre-treated crushed material is graded according to the preset size to obtain the first particle size material and the second particle size material, wherein the particle size of the first particle size material is greater than the particle size of the second particle size material. The first particle size material is re-selected and impurities are separated by the first re-selection unit to obtain the first particle size re-selection concentrate and the first particle size re-selection tailings; the second particle size material is re-selected and impurities are separated by the second re-selection unit to obtain the second particle size re-selection concentrate and the second particle size re-selection tailings. The second particle size re-selection concentrate and the second particle size re-selection tailings are subjected to sedimentation and filtration by the sedimentation filter press unit to obtain a dehydrated second particle size product. The re-selection and impurity removal system for treating low-grade bauxite provided by the present application can obtain aluminum concentrate with high alumina content, high aluminum-silicon ratio, and relatively low impurity content, and obtain tailings with high silicon dioxide content. The whole system has low operating costs, simple processes, and no chemical agents are added during the whole re-selection and impurity removal process. The concentrate is suitable for the production of alumina, and the tailings are used in the building materials industry. It can effectively reduce the ore consumption of low-grade bauxite in the production of alumina and reduce the amount of red mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0034] Figure 1 A schematic diagram of the architecture of a system for re-selecting and removing impurities from low-grade bauxite provided in an embodiment of the present application;

[0035] Figure 2 A schematic structural diagram of a system for re-selecting and removing impurities from low-grade bauxite provided in an embodiment of the present application;

[0036] Figure 3 A schematic structural diagram of a first heavy medium cyclone according to an embodiment of the present application;

[0037] Figure 4 A schematic structural diagram of a first dual-channel media removal and washing screen at an angle according to an embodiment of the present application;

[0038] Figure 5 A schematic structural diagram of a first dual-channel media removal and washing screen from another angle according to an embodiment of the present application;

[0039] Figure 6 A schematic structural diagram of a double-drum centrifugal concentrator at one angle according to an embodiment of the present application;

[0040] Figure 7 A schematic structural diagram of a double-drum centrifugal ore concentrator from another angle according to an embodiment of the present application.

[0041] in, Figures 1 to 7 The corresponding relationship between the reference numerals and the component names is as follows:

[0042] 100 crushing unit, 101 crusher, 102 rod mill, 200 pretreatment classification unit, 201 storage tank, 203 raw material slurry pump, 204 3mm linear screen, 205 ore washing equipment, 206 0.5mm classification linear screen, 207 high-frequency rotary vibrating screen, 300 first gravity separation unit, 301 first heavy medium mixing barrel, 302 first slurry pump, 303 first heavy medium cyclone, 304 first double-channel de-medium washing screen, A de-medium zone, B washing zone, C dehydration zone, 3041 de-medium discharge port, 3042 washing discharge port, 3043 partition, 3044 overflow feed port, 3045 underflow feed port, 3046 overflow discharge port, 3047 underflow discharge port, 3048 spray pipe, 305 second heavy medium mixing barrel, 306 second slurry pump, 307 second heavy medium cyclone, 3 08 second double-channel de-mediating 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 particle size tailings mixing barrel, 405 second particle size tailings slurry pump, 406 second particle size concentrate mixing barrel, 407 second particle size concentrate slurry pump, 408 barrel pump, 500 medium recovery and reuse unit, 501 first magnetic separator, 502 second magnetic separator, 600 sedimentation filter press unit, 601 second particle size gravity separation tailings sedimentation tank, 602 second particle size gravity separation concentrate sedimentation tank. DETAILED DESCRIPTION

[0043] In order to better understand the above-mentioned technical scheme, the technical scheme of the embodiments of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical scheme of the embodiments of the present application, rather than limitations on the technical scheme of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0044] like Figures 1 to 7 As shown, according to an embodiment of the present application, a re-selection and impurity removal system for processing low-grade bauxite is proposed, comprising: a crushing unit 100, used for crushing raw materials to obtain crushed materials;

[0045] The pretreatment and grading unit 200 is used to pretreatment the above-mentioned crushed material, and to grade the above-mentioned crushed material after pretreatment according to preset sizes to obtain first particle size material and second particle size material, wherein the particle size of the above-mentioned first particle size material is larger than the particle size of the above-mentioned second particle size material; the first gravity separation unit 300 is used to gravity-separate and remove impurities from the above-mentioned first particle size material to obtain first particle size gravity separation concentrate and first particle size gravity separation tailings; the second gravity separation unit 400 is used to gravity-separate and remove impurities from the above-mentioned second particle size material to obtain second particle size gravity separation concentrate and second particle size gravity separation tailings; the sedimentation and filtration unit 600 is used to sediment and filter the above-mentioned second particle size gravity separation concentrate and the above-mentioned second particle size gravity separation tailings to obtain a dehydrated second particle size product.

[0046] It can be understood that the re-selection and impurity removal system for processing low-grade bauxite provided in the embodiment of the present application includes a crushing unit 100, a pre-treatment classification unit 200, a first re-selection unit 300, a second re-selection unit 400 and a sedimentation filter press unit 600. Among them, the crushing unit 100 is used to crush the raw material to obtain a crushed material, and then the crushed material is cleaned and pre-treated by the pre-treatment classification unit 200, and the pre-treated crushed material is graded according to a preset size to obtain a first particle size material and a second particle size material, wherein the particle size of the first particle size material is greater than that of the second particle size material. The first particle size material is re-selected and impurities are separated by the first re-selection unit 300 to obtain a first particle size re-selection concentrate and a first particle size re-selection tailing; the second particle size material is re-selected and impurities are separated by the second re-selection unit 400 to obtain a second particle size re-selection concentrate and a second particle size re-selection tailing. The second-grade gravity separation concentrate and the second-grade gravity separation tailings are subjected to sedimentation and pressure filtration by the sedimentation and pressure filtration unit 600 to obtain a dehydrated second-grade product. The gravity separation and impurity removal system for treating low-grade bauxite provided in this application can obtain an aluminum concentrate with a high alumina content, a high aluminum-silicon ratio, and a relatively low impurity content, and obtain tailings with a high silica content. The entire system has low operating costs, a simple process, and no chemical agents are added during the entire gravity separation and impurity removal process. The concentrate is suitable for the production of alumina, and the tailings are used in the building materials industry. It can effectively reduce the ore consumption of low-grade bauxite in the production of alumina and reduce the amount of red mud.

[0047] It should be noted that the aluminum oxide content of low-grade bauxite is 50% to 55%, the silicon dioxide content is more than 20%, the illite content in the raw ore is more than 20%, and the aluminum-silicon ratio is 2.0 to 2.75. For example, the aluminum oxide content of the selected low-grade bauxite is 53.56%, the silicon dioxide content is 21.36%, the illite content in the raw ore is 23%, and the aluminum-silicon ratio is 2.50.

[0048] It can be understood that the pretreatment classification unit 200 can be provided with a storage tank 201, a raw material slurry pump 203, a 3mm linear screen 204, a washing device 205, a 0.5mm grading linear screen 206 and a high-frequency rotary vibrating screen 207. After the crushing unit 100 crushes the raw material, it can be placed in the storage tank 201, and the raw material slurry pump 203 is used to drive the 3mm linear screen 204 for classification. The ore on the screen has a large particle size and needs to be returned to the crushing unit 100 for further processing. The ore under the screen enters the washing device 205 for cleaning. After the cleaning is completed, the ore under the screen enters the 0.5mm grading linear screen 206 for classification, wherein the ore with a particle size of -3+0.5mm enters the first gravity separation unit 300; the material with a particle size less than 0.5mm enters the high-frequency rotary vibrating screen 207 for classification, wherein the ore of -5+0.15mm is ground again by the rod mill 102, and the ore of -0.15mm enters the second gravity separation unit 400.

[0049] It should be noted that the sedimentation filter press unit 600 can send the second grade gravity separation concentrate into the second grade gravity separation concentrate sedimentation tank 602, and send the second grade gravity separation tailings into the second grade gravity separation tailings sedimentation tank 601, and after a period of sedimentation, it is pumped into the plate filter press and filtered into a filter cake.

[0050] In some examples, such as Figure 1 and Figure 2 As shown, it also includes: a medium recovery and reuse unit 500, which is used to process the product obtained after the first particle size material is re-selected and separated to obtain a medium, and recover the above medium for reuse.

[0051] It is understandable that the first gravity separation unit 300 needs to use heavy medium when performing gravity separation and impurity removal on the first particle size material. The heavy medium can be a suspension of water, ferrosilicon powder and magnetic powder. The density of the suspension can be determined according to the process flow. The medium recovery and reuse unit 500 can be provided with a heavy medium recovery magnetic separator. After the first gravity separation unit 300 performs the medium removal and washing process on the material, the medium removed and washed out can be reused by the heavy medium recovery magnetic separator or re-entered into the heavy medium mixing barrel of the first gravity separation unit 300 for use, thereby reducing raw material damage and saving costs.

[0052] In some examples, such as Figure 2 As shown, the crushing unit 100 includes: a jaw crusher 101, a cone crusher 101 and a rod mill 102; wherein, the discharge port of the rod mill 102 is the peripheral discharge of the end, and the rod body of the rod mill 102 occupies 1 / 4 to 1 / 2 of the cavity volume of the rod mill 102; the liquid-to-solid ratio of the liquid in the cavity of the rod mill 102 and the raw material is 0.4 to 0.65; the crushed material after being processed by the rod mill 102 is an ore with a particle size of -3mm, and the material with a particle size of -3+0.5mm accounts for 50% to 65% of the crushed material.

[0053] It can be understood that the crushing unit 100 can be provided with a jaw crusher 101, a cone crusher 101 and a rod mill 102 to gradually reduce the particle size of the material. The crushed material after being processed by the last rod mill 102 is an ore with a particle size of -3mm, and the material with a particle size of -3+0.5mm accounts for 50% to 65% of the crushed material.

[0054] It should be noted that the specific value of the maximum crushing particle size of the ore can be determined according to the basic properties of the selected ore and through process mineralogy research. The value of the maximum crushing particle size of the ore can directly affect the effect of gravity separation. By determining the maximum crushing particle size of the ore, the number of steel bars in the rod mill 102 and the liquid-solid ratio can be adjusted.

[0055] For example, the maximum crushing particle size of the ore is 3 mm, the volume of the steel rod is 2 / 5 of the volume of the rod mill 102 cavity, the liquid-solid ratio is 0.55, and the proportion of -3+0.5 mm in this material is 60%.

[0056] In some examples, the particle size of the first particle size material obtained after being processed by the pretreatment grading unit 200 is -n+0.5mm, wherein n is the maximum particle size of the first particle size material, and the value range of n is 1mm to 4mm; the particle size of the second particle size material obtained after being processed by the pretreatment grading unit 200 is -0.15mm; wherein the material with a particle size of -0.5+0.15mm obtained after being processed by the pretreatment grading unit 200 is returned to the rod mill 102 for further grinding, so as to improve the grading accuracy of the first particle size material and the second particle size material, avoid misclassification, and reduce raw material waste.

[0057] Exemplarily, n can be 3, the first particle size material is -3+0.5 mm, accounting for 60%; the second particle size material is -0.15 mm, accounting for 40%.

[0058] In some examples, such as Figures 1 to 3 As shown, the first gravity separation unit 300 comprises: a first gravity separation impurity removal component and a second gravity separation impurity removal component. The first size material is subjected to a first gravity separation impurity removal separation by the first gravity separation impurity removal component to obtain a first gravity separation concentrate and a first size gravity separation tailings; the first gravity separation concentrate is subjected to a second gravity separation impurity removal separation by the second gravity separation impurity removal component to obtain a first size gravity separation concentrate and a second gravity separation tailings, and the second gravity separation tailings are returned to the first gravity separation impurity removal component for another gravity separation impurity removal.

[0059] It is understandable that the first gravity separation unit 300 may be provided with a first gravity separation impurity removal component and a second gravity separation impurity removal component, and the screening particle size of the first gravity separation unit 300 is greater than the screening particle size of the second gravity separation unit 400. Among them, the first-grade material separated by the pretreatment classification unit 200 can first be subjected to a first gravity separation impurity removal separation by the first gravity separation impurity removal component to obtain a first gravity separation concentrate and a first-grade gravity separation tailings to achieve a roughing process. After the roughing is completed, the first gravity separation concentrate is subjected to a second gravity separation impurity removal separation by the second gravity separation impurity removal component to obtain a first-grade gravity separation concentrate and a second gravity separation tailings, and the second gravity separation tailings are re-introduced into the first gravity separation impurity removal component for further processing. Through the roughing and concentrating process, the grade and recovery rate of the first-grade concentrate can be guaranteed, and the utilization rate of low-grade bauxite can be improved. And the separation of aluminum minerals and impurity minerals can be better achieved.

[0060] In some examples, the separation density of the first gravity separation and impurity removal operation of the first gravity separation and impurity removal component is 1.5 g / cm 3 Up to 1.9 / cm 3 The feeding pressure is 0.08Mpa to 0.12Mpa; the separation density of the secondary gravity separation and impurity removal operation of the above-mentioned second gravity separation and impurity removal component is 2.0g / cm 3 Up to 2.9 / cm 3 , the feeding pressure is 0.14Mpa to 0.2Mpa.

[0061] It can be understood that the sorting density of the primary re-selection and impurity removal operation is less than the sorting density of the secondary re-selection and impurity removal operation of the second re-selection and impurity removal component, and the feeding pressure of the primary re-selection and impurity removal operation is less than the feeding pressure of the secondary re-selection and impurity removal operation. The sorting density and feeding pressure can be set as above to realize the roughing and concentrating process flow, ensure the grade and recovery rate of the first particle size concentrate, and improve the utilization rate of low-grade bauxite. And it can better realize the separation of aluminum minerals and impurity minerals.

[0062] For example, the separation density of a gravity separation operation is 1.85 g / cm 3 The feeding pressure is 0.1Mpa; the separation density of the secondary gravity separation and impurity removal operation is 2.0g / cm 3 , the feeding pressure is 0.16Mpa.

[0063] In some examples, such as Figures 2 to 5As shown, the first re-selection impurity removal component includes: a first heavy medium stirring barrel 301, a first slurry pump 302, a first heavy medium cyclone 303, and a first double-channel de-medium washing screen 304; the second re-selection impurity removal component includes: a second heavy medium stirring barrel 305, a second slurry pump 306, a second heavy medium cyclone 307, and a second double-channel de-medium washing screen 308; during the above-mentioned one-time re-selection impurity removal operation, the first particle size material enters the first heavy medium stirring barrel 301, and is pumped into the first heavy medium cyclone 303 through the first slurry pump 302. The overflow and underflow of the first heavy medium cyclone 303 pass through the first double-channel de-medium washing screen 304 to separate the medium, and then remain in the first heavy medium cyclone 303. The overflow screen ore is the first-grade gravity-separation tailings, and the bottom-flow screen ore remaining in the first heavy medium cyclone 303 is the primary gravity-separation concentrate; in the secondary gravity-separation impurity removal process, the primary gravity-separation concentrate enters the second heavy medium stirring barrel 305, and is pumped into the second heavy medium cyclone 307 through the second slurry pump 306. After the overflow and bottom flow of the second heavy medium cyclone 307 pass through the second double-channel de-medium washing screen 308 to separate the medium, the bottom-flow screen ore remaining in the second heavy medium cyclone 307 is the first-grade gravity-separation concentrate, and the overflow screen ore remaining in the second heavy medium cyclone 307 is the secondary gravity-separation tailings, which return to the first heavy medium stirring barrel 301 to repeat the primary gravity-separation impurity removal process.

[0064] It can be understood that the first gravity separation and impurity removal component can be provided with a first heavy medium stirring barrel 301, a first slurry pump 302, a first heavy medium cyclone 303, and a first dual-channel de-medium washing screen 304. Specifically, when performing a gravity separation and impurity removal operation, the first heavy medium suspension can be prepared first, and then the first particle size material can be put into the first heavy medium stirring barrel 301, and then pumped into the first heavy medium cyclone 303 through the first slurry pump 302, and the first heavy medium cyclone 303 is used for screening, and the first heavy medium cyclone 303 is connected to the first dual-channel de-medium washing screen 304, wherein the overflow of the first heavy medium cyclone 303 enters the first dual-channel de-medium washing screen 304 through the overflow feed port 3044; the underflow of the first heavy medium cyclone 303 enters the first dual-channel de-medium washing screen 304 through the underflow feed port 3045, and then the de-medium washing operation is performed through the first dual-channel de-medium washing screen 304. The overflow screen ore after the stripping and washing operation is completed is output through the overflow discharge port 3046, and the processed overflow screen ore is the first-grade gravity separation tailings. The underflow screen ore after the stripping and washing operation is completed is output through the underflow discharge port 3047, and the underflow screen ore remaining in the first heavy medium cyclone 303 after processing is the primary gravity separation concentrate, thereby realizing the coarse screening operation of the first-grade material.

[0065] It can be understood that the second gravity separation impurity removal component can be provided with a second heavy medium stirring barrel 305, a second slurry pump 306, a second heavy medium cyclone 307, and a second double-channel de-mediation and washing screen 308. Specifically, when performing the secondary gravity separation and impurity removal operation, the second heavy medium suspension can be prepared first, and then the primary gravity separation concentrate is put into the first heavy medium stirring barrel 301, and then pumped into the second heavy medium cyclone 307 through the second slurry pump 306, and the second heavy medium cyclone 307 is screened, and the second heavy medium cyclone 307 is connected to the second double-channel de-mediation and washing screen 308, wherein the overflow and underflow of the second heavy medium cyclone 307 are respectively de-mediated and washed through the second double-channel de-mediation and washing screen 308. The treated overflow screen ore is the secondary gravity separation tailings, and the underflow screen ore remaining in the first heavy medium cyclone 303 is the first-grade gravity separation concentrate, thereby realizing the fine screening operation of the first-grade material. The secondary gravity separation tailings need to be put back into the first gravity separation impurity removal component for coarse screening, and then put into the second gravity separation impurity removal component for fine screening to ensure the grade and recovery rate of the first particle size concentrate, improve the utilization rate of low-grade bauxite, and better separate aluminum minerals from impurity minerals.

[0066] It should be noted that the density of the first heavy medium suspension is less than the density of the second heavy medium suspension.

[0067] It should be noted that if Figure 4 and Figure 5 As shown, the first dual-channel de-medium washing screen 304 is provided with two under-screen discharge ports, namely, the de-medium discharge port 3041 and the washing discharge port 3042. The suspension flowing out of the de-medium discharge port 3041 can be directly returned to the heavy medium mixing barrel; the heavy medium and water attached to the product are sprayed off and flow into the heavy medium recovery magnetic separator to recover the heavy medium and return to the heavy medium mixing barrel for reuse. The screen surface is provided with a partition 3043, and the position of the partition 3043 can be adjusted according to the basic properties of the ore. The first dual-channel de-medium washing screen 304 and the second dual-channel de-medium washing screen 308 can use the same structure.

[0068] Exemplarily, the layout of the double-channel de-mediation and media washing screen surface is that the screen surface length is 4m, from the feed section to 2m is the de-mediation zone A, 2m to 3.5m is the media washing zone B, and multiple spray pipes 3048 are added to the upper end of the media washing zone B, and the specific number depends on the on-site effect. 3.5m to 4m is the dehydration zone C.

[0069] In some examples, the first heavy medium cyclone 303 and the second heavy medium cyclone 307 constitute a two-stage series heavy medium cyclone, and the placement angle of the two-stage series heavy medium cyclone and the angle between the horizontal plane are 15° to 20°; the cone angle of the two-stage series heavy medium cyclone is 20° to 40°; the bottom flow port diameter of the two-stage series heavy medium cyclone is 20mm to 30mm; the overflow port diameter of the two-stage series heavy medium cyclone is 60mm to 70mm; the length of the central overflow pipe of the two-stage series heavy medium cyclone is 300mm to 450mm; wherein, the bottom flow port diameter of the second heavy medium cyclone 307 is smaller than the bottom flow port diameter of the first heavy medium cyclone 303.

[0070] It can be understood that the first heavy medium cyclone 303 and the second heavy medium cyclone 307 can constitute a two-stage series heavy medium cyclone, so that the first heavy medium cyclone 303 The concentrate on the bottom flow screen can be quickly put into the second heavy medium cyclone 307, shortening the process route and improving efficiency. And the first heavy medium cyclone 303 and the second heavy medium cyclone 307 form an angle with the horizontal plane to achieve a better sorting effect. Among them, the overflow port diameter and the center overflow pipe length of the first heavy medium cyclone 303 and the second heavy medium cyclone 307 can use the same parameters, and the bottom flow port diameter of the second heavy medium cyclone 307 is smaller than the bottom flow port diameter of the first heavy medium cyclone 303, so as to ensure that the second heavy medium cyclone 307 has a higher screening accuracy, so as to ensure the grade of the first particle size concentrate.

[0071] For example, Figure 3 As shown, the first heavy medium cyclone 303 is placed at an angle of 20° to the horizontal plane, the bottom flow port diameter is 25 mm, the overflow port diameter is 60 mm, and the center overflow pipe length is 400 mm.

[0072] In some examples, such as Figure 6 and Figure 7 As shown, the second gravity separation unit 400 includes: a double-drum centrifugal concentrator 402, which is provided with a first drum body 4021 and a second drum body 4022, the inclined angles of the first drum body 4021 and the second drum body 4022 are 2° to 8°, the first drum body 4021 is used for performing a centrifugal impurity removal on the second particle size to obtain a first impurity-removed tailing and a first impurity-removed concentrate; the second drum body 4022 is used for performing a second centrifugal impurity removal on the first impurity-removed tailing to obtain a second particle size gravity separation tailing and a second impurity-removed concentrate, wherein the first impurity-removed concentrate and the second impurity-removed concentrate are combined into a second particle size gravity separation concentrate; wherein the diameter of the first drum body 4021 is smaller than the diameter of the second drum body 4022.

[0073] It can be understood that the second re-selection unit 400 is provided with a feed mixing barrel 401, a double-drum centrifugal concentrator 402, a second-grade tailings mixing barrel 404, a second-grade tailings slurry pump 405, a second-grade concentrate mixing barrel 406, a second-grade concentrate slurry pump and a barrel pump 408. Among them, the second-grade material can be pumped into the feed mixing barrel 401 by the barrel pump 408, and enter the double-drum centrifugal concentrator 402 by gravity. The second-grade material will first flow into the first drum body 4021 for primary centrifugal impurity removal. The tailings after the primary centrifugal impurity removal will flow into the second drum body 4022 with the water flow for secondary centrifugal impurity removal. The tailings after the secondary centrifugal impurity removal will flow out directly as the second-grade centrifugal tailings. After the ore is cut off, the flushing water is turned on to flush out the primary centrifugal concentrate attached to the side wall of the first drum body 40214021 and the secondary centrifugal concentrate on the side wall of the second drum body 4022, and merge them into the second-grade centrifugal concentrate. The second-grade centrifugal tailings flow into the second-grade tailings stirring barrel 404, and the slurry is pumped into the sedimentation filter press unit 600 for sedimentation filter press by the second-grade tailings slurry pump 405. The second-grade centrifugal concentrate flows into the second-grade concentrate stirring barrel 406, and the slurry is pumped into the sedimentation filter press unit 600 for sedimentation filter press by the second-grade concentrate slurry pump.

[0074] It should be noted that the inclined surfaces of the first drum body 4021 and the second drum body 4022 have an inclination angle of 2° to 8°, and the inclination angle of the first drum body 4021 is greater than the inclination angle of the second drum body 4022. For example, the inclination angle of the first drum body 4021 is 6°, and the inclination angle of the inclined surface of the second drum body 4022 is 2°.

[0075] It is understandable that the double-drum centrifugal concentrator 402 can also be provided with a feed port, an automatic control cabinet 403, a discharge port, a flushing water pipe, a rinsing water pipe and an automatic control cabinet 403. Among them, the automatic control cabinet 403 can be used to control the drum frequency of the first drum body 4021 and the second drum body 4022, and the control range is 20Hz to 40Hz; the amount of rinsing water is controlled to be 300L / h to 500L / h; and an automatic program is set under automatic control, which is divided into the initial stage, the ore feeding stage, the ore breaking stage, the flushing stage and the end stage. The operation time can be set for each stage. The initial stage only appears once each time the machine is turned on, and it is cyclically carried out in this order. Setting the drum frequency and the amount of rinsing water can directly affect the effect of the centrifugal concentrator's gravity separation and impurity removal; the setting of the time for each stage can increase the equipment's processing capacity without affecting the gravity separation effect. The feed port and the discharge port are connected to the cylinder, air pump and air compressor to realize automatic control. Specifically, when entering the feeding stage, the feed port will swing towards the feed port, and the discharge port will swing towards the tailings discharge port. The material will flow into the centrifugal concentrator for sorting, and the tailings will flow out immediately; when entering the ore-breaking stage, the feed port will swing towards the circulation return port, and the material will be pumped back to the feeding mixing barrel 401 through the barrel pump 408 for circulation. After the preset time, the drum frequency will automatically decrease to 10hz; when entering the flushing stage, the discharge port will quickly swing towards the concentrate discharge port, and the flushing water solenoid valve will open; when the system enters the end stage, the drum frequency automatically rises to the set value; the feeding method is gravity feeding, and the feeding amount can be controlled by adjusting the valve size.

[0076] Exemplarily, the automatic control cabinet 403 can control the drum frequency of the first drum body 4021 and the second drum body 4022 to be 30 Hz, control the amount of rinsing water to be 400 L / h, and the five stage setting times of the automation program are 10s, 30s, 6s, 10s and 5s respectively.

[0077] In some examples, the heavy medium used in the first re-selection unit 300 includes ferrosilicon powder and magnet powder, the ratio of the ferrosilicon powder to the magnet powder is 1:3, and the particle sizes of the ferrosilicon powder and the magnet powder are both less than 0.038 mm.

[0078] It can be understood that the heavy medium recovery magnetic separator can be provided with a first magnetic separator 501 and a second magnetic separator 502, wherein the first magnetic separator 501 is used to recover the heavy medium of the primary gravity separation concentrate and the first particle size gravity separation tailings; the second magnetic separator 502 is used to recover the heavy medium of the first particle size gravity separation concentrate and the secondary gravity separation tailings.

[0079] For example, when the selected low-grade bauxite has an alumina content of 53.56%, a silica content of 21.36%, an illite content of 23% in the raw ore, and an aluminum-silicon ratio of 2.50, the above exemplary parameters are used to obtain a first-grade concentrate with a yield of 40.10%, an alumina content of 66.65%, and an aluminum-silicon ratio of 7.61; a second-grade concentrate with a yield of 11.15%, an alumina content of 59.36%, and an aluminum-silicon ratio of 5.31, achieving efficient utilization of low-grade bauxite. The specific experimental results are shown in Table 1, where A / S is the aluminum-silicon ratio.

[0080] Table 1 Test results of Example 1

[0081] product Yield / % <![CDATA[Al2O3 / %]]> <![CDATA[SiO2 / %]]> <![CDATA[Fe2O3 / %]]> A / S Coarse concentrate 40.10 66.65 8.76 7.61 7.61 Coarse tailings 33.08 38.50 33.15 1.16 1.16 Fine Concentrate 11.15 59.36 11.19 4.85 5.31 Fine tailings 15.67 35.48 28.72 1.23 1.24 Ore 100.00 51.64 20.23 4.17 2.55

[0082] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0083] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0084] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0085] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A re-selection and impurity removal system for processing low-grade bauxite, characterized in that: include: A crushing unit, used for crushing raw materials to obtain crushed materials; A pretreatment and grading unit, used for pretreatment of the crushed material, and grading the crushed material after pretreatment according to a preset size to obtain a first particle size material and a second particle size material, wherein the particle size of the first particle size material is greater than that of the second particle size material; A first gravity separation unit is used for gravity separation and impurity removal of the first particle size material to obtain a first particle size gravity separation concentrate and a first particle size gravity separation tailings; A second gravity separation unit is used for gravity separation and impurity removal of the second particle size material to obtain a second particle size gravity separation concentrate and a second particle size gravity separation tailings; The sedimentation and filtration unit is used for sedimentation and filtration of the second particle size gravity separation concentrate and the second particle size gravity separation tailings to obtain a dehydrated second particle size product.

2. The system for re-selection and impurity removal of low-grade bauxite according to claim 1 is characterized in that: Also includes: The medium recovery and reuse unit is used to obtain the medium by processing the product obtained after the first-grade material is re-selected, impurity-removed and separated, and to recover and reuse the medium.

3. The system for re-selection and impurity removal of low-grade bauxite according to claim 1, characterized in that: The crushing unit comprises: jaw crushers, cone crushers and rod mills; Among them, the discharge port of the rod mill is the peripheral discharge of the end, and the rod body of the rod mill occupies 1 / 4 to 1 / 2 of the cavity volume of the rod mill; the liquid-to-solid ratio of the liquid in the cavity of the rod mill and the raw material is 0.4 to 0.65; the crushed material after being processed by the rod mill is ore with a particle size of -3mm, and the material with a particle size of -3+0.5mm accounts for 50% to 65% of the crushed material.

4. The system for re-selection and impurity removal of low-grade bauxite according to claim 3 is characterized in that: The particle size of the first-grade material obtained after being processed by the pretreatment and classification unit is -n+0.5 mm, wherein n is the maximum particle size of the first-grade material, and the value range of n is 1 mm to 4 mm; The particle size of the second particle size material obtained after being processed by the pretreatment classification unit is -0.15 mm; The material with a particle size of -0.5+0.15 mm obtained after being processed by the pretreatment and classification unit is returned to the rod mill for further grinding.

5. The system for re-selection and impurity removal of low-grade bauxite according to claim 2, characterized in that: The first reselection unit comprises: The first gravity separation impurity removal component and the second gravity separation impurity removal component are used for the first particle size material to undergo a first gravity separation impurity removal separation to obtain a first gravity separation concentrate and a first particle size gravity separation tailings; the first gravity separation concentrate is subjected to a second gravity separation impurity removal separation by the second gravity separation impurity removal component to obtain a first particle size gravity separation concentrate and a second gravity separation tailings, and the second gravity separation tailings are returned to the first gravity separation impurity removal component for another gravity separation impurity removal.

6. The system for re-selection and impurity removal of low-grade bauxite according to claim 5, characterized in that: The separation density of the first gravity separation and impurity removal component in a gravity separation and impurity removal operation is 1.5 g / cm 3 Up to 1.9 / cm 3 , the feeding pressure is 0.08Mpa to 0.12Mpa; The separation density of the secondary gravity separation and impurity removal operation of the second gravity separation and impurity removal component is 2.0g / cm 3 Up to 2.9 / cm 3 , the feeding pressure is 0.14Mpa to 0.2Mpa.

7. The system for re-selection and impurity removal of low-grade bauxite according to claim 6, characterized in that: The first gravity separation and impurity removal component includes: a first heavy medium stirring barrel, a first slurry pump, a first heavy medium cyclone, and a first double-channel medium removal and washing screen; the second gravity separation and impurity removal component includes: a second heavy medium stirring barrel, a second slurry pump, a second heavy medium cyclone, and a second double-channel medium removal and washing screen; During the primary gravity separation and impurity removal operation, the first particle size material enters the first heavy medium stirring barrel, and is pumped into the first heavy medium cyclone through the first slurry pump. After the overflow and underflow of the first heavy medium cyclone pass through the first double-channel de-medium washing screen to separate the medium, the ore on the overflow screen of the first heavy medium cyclone is the first particle size gravity separation tailings, and the ore on the underflow screen of the first heavy medium cyclone is the primary gravity separation concentrate; During the secondary gravity separation and impurity removal process, the primary gravity separation concentrate enters the second heavy medium stirring barrel, and is pumped into the second heavy medium cyclone through the second slurry pump. After the overflow and underflow of the second heavy medium cyclone pass through the second double-channel de-medium washing screen to separate the medium, the ore on the underflow screen of the second heavy medium cyclone is the first particle size gravity separation concentrate, and the ore on the overflow screen of the second heavy medium cyclone is the secondary gravity separation tailings, which returns to the first heavy medium stirring barrel to repeat the primary gravity separation and impurity removal process.

8. The system for re-selection and impurity removal of low-grade bauxite according to claim 7, characterized in that: The first heavy medium cyclone and the second heavy medium cyclone constitute a two-stage series heavy medium cyclone, the placement angle of the two-stage series heavy medium cyclone and the angle between the horizontal plane are 15° to 20°; the cone angle of the two-stage series heavy medium cyclone is 20° to 40°; the bottom flow port diameter of the two-stage series heavy medium cyclone is 20mm to 30mm; the overflow port diameter of the two-stage series heavy medium cyclone is 60mm to 70mm; the central overflow pipe length of the two-stage series heavy medium cyclone is 300mm to 450mm; Wherein, the diameter of the bottom flow port of the second heavy medium cyclone is smaller than the diameter of the bottom flow port of the first heavy medium cyclone.

9. The system for re-selection and impurity removal of low-grade bauxite according to claim 1, characterized in that: The second reselection unit comprises: A double-drum centrifugal concentrator, wherein the double-drum centrifugal concentrator is provided with a first drum body and a second drum body, wherein the inclined surfaces of the first drum body and the second drum body have an inclination angle of 2° to 8°, wherein the first drum body is used to perform a primary centrifugal impurity removal on the second particle size to obtain a primary impurity-removed tailing and a primary impurity-removed concentrate; and the second drum body is used to perform a secondary centrifugal impurity removal on the primary impurity-removed tailing to obtain a second particle size gravity-removed tailing and a secondary impurity-removed concentrate, wherein the primary impurity-removed concentrate and the secondary impurity-removed concentrate are combined into a second particle size gravity-removed concentrate; Wherein, the diameter of the first rotating drum body is smaller than the diameter of the second rotating drum body.

10. The system for re-selection and impurity removal of low-grade bauxite according to claim 7, characterized in that: The heavy medium used in the first gravity separation unit includes ferrosilicon powder and magnet powder, the ratio of the ferrosilicon powder to the magnet powder is 1:3, and the particle sizes of the ferrosilicon powder and the magnet powder are both less than 0.038 mm.

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