Separation method of gibbsite bauxite with high silicon content

Abstract

The invention relates to the technical field of screening and separation of bauxite, in particular to a separation method of gibbsite bauxite with high silicon content. The separation method comprises the following steps: performing primary grading treatment on gibbsite bauxite to obtain coarse-fraction raw ore and fine-fraction raw ore; carrying out photoelectric separation pretreatment on the coarse-fraction raw ore to obtain pre-selected concentrate and pre-selected tailings; the pre-selected tailings are crushed, pre-selected tailing crushed objects and the fine-fraction raw ore are sequentially combined and subjected to secondary grading treatment, and coarse-fraction treated ore and fine-fraction treated ore are obtained; the coarse-fraction treated ore is subjected to first separation, and coarse-fraction concentrate is obtained; the fine-fraction treated ore is subjected to secondary separation, and fine-fraction concentrate is obtained; the pre-selected concentrate, the coarse-fraction concentrate and the fine-fraction concentrate are combined, and aluminum concentrate is obtained; and the coarse-fraction tailings are combined, and separated tailings are obtained. The separation method can obviously improve the grade of the aluminum concentrate.

Description

Technical Field

[0001] This application relates to the field of bauxite screening and separation technology, and in particular to a method for separating high-silicon-content gibbsite-type bauxite. Background Technology

[0002] With the increasing scarcity of high-quality bauxite resources, the industry's reliance on imported bauxite has risen sharply. Currently, the main type of bauxite is gibbsite, characterized by high aluminum and silicon content and a low aluminum-to-silicon ratio. Furthermore, a significant proportion of the bauxite is of medium to low grade, and the trihydrate gibbsite type among these medium to low grade ores is particularly difficult to process. Moreover, as bauxite quality declines, the content of gangue minerals in the bauxite increases, leading to numerous problems in alumina production, such as increased alkali consumption, increased red mud content, rising costs, and declining alumina quality. Therefore, there is an urgent need to improve the quality and efficiency of bauxite resources.

[0003] Currently, the efficient utilization of bauxite resources generally involves first removing impurities from the bauxite through conventional flotation desilication technology. However, conventional flotation desilication technology has the problem of producing low-grade aluminum concentrate. Summary of the Invention

[0004] This application provides a separation method for high-silicon-content gibbsite-type bauxite to solve the following technical problem: how to improve the grade of aluminum concentrate.

[0005] In a first aspect, embodiments of this application provide a method for separating high-silicon-content gibbsite-type bauxite, the separation method comprising: The trihydrate gibbsite type bauxite is subjected to a primary classification process to obtain coarse-grained raw ore and fine-grained raw ore. The coarse-grained raw ore is subjected to photoelectric separation pretreatment to obtain pre-selected concentrate and pre-selected tailings; The pre-selected tailings are crushed to obtain pre-selected tailings crushed material; The pre-selected tailings crushed material and the fine-grained raw ore are sequentially combined and subjected to secondary classification to obtain coarse-grained processed ore and fine-grained processed ore. The coarse-grained ore is first sorted to obtain coarse-grained concentrate; The fine-grained processed ore is subjected to a second sorting to obtain a fine-grained concentrate. The pre-selected concentrate, the coarse-grained concentrate, and the fine-grained concentrate are combined to obtain aluminum concentrate.

[0006] Optionally, the sorting threshold for the photoelectric sorting preprocessing is 12800 to 13200.

[0007] Optionally, the light source intensity for the photoelectric sorting pretreatment is 50kV to 70kV.

[0008] Optionally, the photoelectric sorting pretreatment is performed by feeding with vibration, and the vibration frequency of the photoelectric sorting pretreatment is 30Hz to 40Hz.

[0009] Optionally, the target particle size for the primary grading process is 3 mm to 3.5 mm; and / or The target particle size for the secondary grading process is 0.15 mm to 0.20 mm; and / or The particle size of the trihydrate gibbsite bauxite is ≤20mm.

[0010] Optionally, the first separation is carried out by interference separation, the feed mass concentration of the first separation is 20% to 30%, and the water flow velocity of the first separation is 15 cm / s to 20 cm / s.

[0011] Optionally, the bed density of the first sorting step is 1.9 g / cm³. 3 Up to 2.1 g / cm 3 The pressure difference of the bed in the first sorting is 8 kPa to 10 kPa.

[0012] Optionally, the second sorting is carried out by centrifugal sorting, with a rotation speed of 300 rpm to 450 rpm and a rinsing water flow rate of 600 L / h to 1000 L / h.

[0013] Optionally, the gibbsite bauxite includes gibbsite aluminum minerals, silica minerals, and iron minerals. The silica minerals include at least one of kaolinite, illite, and pyrophyllite, and the iron minerals include goethite and / or hematite.

[0014] Optionally, the components of the gibbsite bauxite include alumina and silicon dioxide, wherein the mass m1 of the alumina and the mass m2 of the silicon dioxide satisfy the following ratio: m1:m2 = (2.5 to 4.0):1.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for separating high-silicon-content gibbsite-type bauxite. The method first separates the gibbsite-type bauxite into coarse-grained and fine-grained raw ore through a primary classification process. Subsequently, the coarse-grained raw ore undergoes photoelectric separation pretreatment. Based on a preset separation threshold, most of the waste rock in the coarse-grained raw ore that does not contain gibbsite can be directly removed, thereby increasing the grade base of the material entering subsequent separation stages. Furthermore, through crushing and secondary classification, the pre-selected tailings and fine-grained raw ore can be reclassified into coarse-grained processed ore and fine-grained processed ore with a narrower particle size range and more uniform properties. This significantly reduces the probability of gangue minerals mixing into the bauxite concentrate, creating favorable conditions for accurate separation of gibbsite and gangue minerals. Finally, a first separation and a second separation operation were carried out on the coarse-grained and fine-grained processed ores, respectively: the first separation removed coarse-grained gangue minerals from the coarse-grained processed ores; the second separation precisely separated fine-grained gibbsite from fine-grained gangue minerals and slime in the fine-grained processed ores, preventing gangue minerals from being carried into the aluminum concentrate. This separation method not only improved the recovery rate of useful minerals, but also fundamentally reduced the contamination of gangue minerals, resulting in a significant improvement in the grade of aluminum concentrate. Attached Figure Description

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

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

[0018] Figure 1 A schematic flowchart of a separation method for high-silicon-content gibbsite-type bauxite provided in this application embodiment; Figure 2 A schematic diagram of the actual process of separating high-silicon-content gibbsite-type bauxite provided in this application embodiment. Detailed Implementation

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

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

[0021] It should be noted that conventional flotation desilication technology has drawbacks such as high initial investment costs, complex process flow, poor applicability to bauxite, and high energy consumption in fine grinding and separation of bauxite, resulting in low-grade aluminum concentrate. Furthermore, the tailings obtained from conventional flotation desilication technology often have fine particle size, high moisture content, and reagent residues, making tailings storage and disposal difficult and increasing the overall cost of conventional flotation desilication technology.

[0022] Based on the aforementioned deficiencies in the prior art, the embodiments of this application provide the following technical solutions: Figure 1 An exemplary schematic diagram of a separation method for high-silicon-content gibbsite-type bauxite provided in an embodiment of this application is shown. Figure 2 An exemplary schematic diagram of the actual process of a separation method for high-silicon-content gibbsite-type bauxite provided in an embodiment of this application is shown. like Figure 1 and Figure 2 As shown in the embodiment of this application, a method for separating high-silicon-content gibbsite-type bauxite is provided, the separation method comprising: S1. Perform a primary classification process on the trihydrate gibbsite-type bauxite to obtain coarse-grained raw ore and fine-grained raw ore; S2. The coarse-grained raw ore is subjected to photoelectric separation pretreatment to obtain pre-selected concentrate and pre-selected tailings; S3. The pre-selected tailings are crushed to obtain pre-selected tailings crushed material; S4. The pre-selected tailings crushed material and the fine-grained raw ore are sequentially combined and subjected to secondary classification to obtain coarse-grained processed ore and fine-grained processed ore; S5. Perform a first sorting on the coarse-grained ore to obtain coarse-grained concentrate; S6. Perform a second sorting on the fine-grained processed ore to obtain fine-grained concentrate; S7. Combine the pre-selected concentrate, the coarse-grained concentrate, and the fine-grained concentrate to obtain aluminum concentrate.

[0023] It should be noted that the equipment used in this photoelectric separation process can be a series-connected vibrating feeder and an XRT intelligent photoelectric separator. The vibrating feeder can be equipped with four inclined discharge ports at its discharge end. These inclined discharge ports can discharge material together and spread it evenly onto each conveyor belt, ensuring the smooth operation of the subsequent XRT intelligent photoelectric separator. The XRT intelligent photoelectric separator has two dual-energy X-ray signals for four-channel processing. By utilizing the different attenuation levels of X-rays penetrating between aluminum concentrate and impurities in coarse-grained raw ore, the grade of the pre-selected concentrate is improved.

[0024] It should be noted that the first separation can use a TBS (teeter bed separator). The operating principle of the first separation is as follows: the coarse-grained ore is fed into the feed well of the TBS teeter bed separator in a tangential direction as a slurry. The slurry is pumped into the distributor at the bottom of the TBS teeter bed separator according to a predetermined pressure and water flow velocity. Then, the slurry is evenly distributed to the bottom of the TBS teeter bed separator by a turbulence plate, forming an upward flowing turbulent water flow and a descending separated material. When the descending separated material meets the upward flowing turbulent water flow, it can form an interference layer or a fluidized bed. The particles in the separated material are disturbed and settle in the TBS teeter bed separator. Since the density of different particles in the separated material is different, the disturbance settling velocity is different, thereby achieving efficient separation of coarse-grained ore. When the TBS interference bed separator reaches a stable operating state, particles with a density higher than the average density of the interference bed in the TBS interference bed separator will enter the sediment stream. This sediment stream can be discharged through the discharge port at the bottom of the TBS interference bed separator, thus achieving material separation. The bottom discharge port of the TBS interference bed separator is controlled by a discharge valve. This discharge valve uses data measured by a density sensor of the interference bed in the TBS interference bed separator. This data is used to control the opening and closing degree of the discharge valve through a chip in the discharge valve.

[0025] It should be noted that the second separation can be carried out using a centrifugal concentrator. The centrifugal drum used in the second separation can be an arc-shaped drum. Compared with the traditional straight drum, the arc-shaped drum is subjected to greater centrifugal force, which can prevent impurity minerals from mixing into the aluminum concentrate, thereby significantly improving the grade of the aluminum concentrate.

[0026] It should be noted that the second separation can use a pump set and a diverter to feed the fine-grained ore into the centrifugal concentrator in batches. Through the action of the pump set and the diverter, the fine-grained ore can flow into the centrifugal concentrator by its own gravity.

[0027] It should be noted that the first separation process yields not only coarse-grained concentrate but also coarse-grained tailings; similarly, the second separation process yields not only fine-grained concentrate but also fine-grained tailings. Combining the coarse-grained tailings and fine-grained tailings yields separated tailings.

[0028] It should be noted that the separation method for high-silicon-content gibbsite bauxite provided in this application systematically solves the pain points of poor adaptability between coarse and fine particle sizes, severe gangue entrainment, and low separation efficiency in conventional gibbsite bauxite separation processes through three core logics: source pre-disposal of waste to improve grade, precise graded separation to control quality, and liberation degree optimization to ensure separation accuracy. Ultimately, this achieves a significant improvement in the grade of the bauxite concentrate. The specific mechanism is as follows: First, the pre-disposal of coarse particles at the source directly raises the base grade of the selected materials.

[0029] 1. Achieving coarse-to-fine path separation through a single hierarchical processing: In gibbsite-type bauxite, the particle size of gibbsite and gangue minerals (quartz, kaolinite, hematite, etc.) varies greatly. A single classification process can separate gibbsite-type bauxite into coarse-grained and fine-grained raw ore, avoiding the efficiency loss of "coarse and fine mixing" in gibbsite-type bauxite and creating conditions for dedicated pre-disposal of coarse-grained raw ore.

[0030] 2. Photoelectric sorting removes large, low-grade waste rock in advance: Photoelectric separation, based on the differences in physical characteristics such as color, density, and atomic number of minerals in gibbsite-type bauxite, can directly remove most of the waste rock (pre-selection tailings) in coarse-grained raw ore that does not contain gibbsite under coarse-grained, non-grinding conditions. This step removes a large amount of gangue minerals that lower the grade at the source, directly increasing the grade base of materials entering subsequent separation stages. At the same time, it avoids the generation of secondary slime from waste rock in gibbsite-type bauxite during subsequent crushing, eliminating the problem of slime adsorbing reagents and carrying gangue into the bauxite concentrate, thus clearing obstacles for subsequent precise separation.

[0031] II. Closed-circuit classification + crushing and dissociation: precise control of the degree of dissociation and particle size stability of the selected materials.

[0032] 1. Targeted crushing, balancing degree of dissociation and prevention of over-wear: Crushing is performed only on the pre-selection tailings containing useful mineral intergrowths, rather than on the whole ore of gibbsite-type bauxite. This crushing process allows for further individual liberation of gibbsite and gangue minerals in the pre-selection tailings, preventing the intergrowths from being mixed into the aluminum concentrate due to insufficient liberation and thus lowering the grade of the aluminum concentrate. It also eliminates over-grinding and mud formation caused by whole ore crushing, reduces the deterioration of the sorting environment by fine mud, and ensures the selectivity of subsequent sorting.

[0033] 2. Secondary grading achieves particle size homogenization, maximizing sorting accuracy: The crushed pre-selected tailings are combined with the original fine-grained ore and then subjected to secondary classification. The mixture of pre-selected tailings crushed material and fine-grained ore is reclassified into coarse-grained and fine-grained processed ore with a narrower particle size range and more uniform properties. Given that the separation accuracy of the sorting equipment is highly dependent on the stability of the feed particle size, feeding a narrow-particle-size mixture can minimize the "sorting parameter mismatch caused by particle size fluctuations," ensuring the sorting equipment is always in optimal working condition. This allows for more precise separation of gibbsite and gangue minerals, significantly reducing the probability of gangue minerals contaminating the aluminum concentrate.

[0034] Third, we offer granular-level dedicated sorting to maximize sorting selectivity and precisely improve quality.

[0035] Conducting first and second separation operations for coarse-grained and fine-grained processed ores respectively is the core step in improving the grade of aluminum concentrate. 1. Coarse-grained ore processing can be adapted to coarse gravity separation processes such as heavy media separation and jigging, or coarse flotation processes, specifically addressing the problem of high liberation degree of coarse-grained minerals, accurately capturing coarse-grained individual gibbsite, and removing coarse-grained gangue minerals. 2. Fine-grained ore processing can be adapted to fine-grained separation processes such as flotation, centrifugal separation, and shaking table, specifically addressing the problems of fine-grained minerals being prone to mud formation and poor separation selectivity. It accurately separates fine-grained gibbsite from fine-grained gangue minerals and slime, preventing gangue minerals from being carried into the aluminum concentrate.

[0036] The particle size separation process completely solves the industry pain point of "incomplete separation of coarse particles and inaccurate separation of fine particles" in conventional mixing processes. It allows gibbsite of different particle sizes to be separated and enriched with the highest efficiency, which not only improves the recovery rate of useful minerals, but also fundamentally reduces the mixing of gangue minerals, thus achieving a leap in the grade of aluminum concentrate.

[0037] IV. Closed-loop quality control throughout the entire process to ensure the quality of the final aluminum concentrate.

[0038] The high-grade pre-selected concentrate obtained from photoelectric separation is combined with the coarse and fine-grained concentrates obtained from particle size separation. All three products are high-grade materials selected from their respective separation stages, with no low-grade intergrowths or waste rock contamination. The coarse-grained tailings after separation are then combined and discharged, and the gibbsite content in the separated tailings has been reduced to an extremely low level. This separation method forms a closed loop for grade control throughout the entire process of "pre-disposal of waste + grading + dissociation + precise separation + product merging," strictly controlling the contamination of gangue minerals from the source, process, and end, ultimately achieving a stable improvement in the grade of aluminum concentrate.

[0039] In some optional embodiments, the sorting threshold of the photoelectric sorting preprocessing is 12800 to 13200.

[0040] In these embodiments, photoelectric sorting pretreatment with a sorting threshold of 12,800 to 13,200 can separate aluminum concentrate and tailings in coarse-grained raw ore, ensuring the purity of pre-selected concentrate and pre-selected tailings and improving the grade of subsequent aluminum concentrate.

[0041] The sorting threshold for the photoelectric sorting preprocessing can be 12800, 12850, 12900, 12950, ​​13000, 13050, 13100, 13150 or 13200.

[0042] It should be noted that the sorting threshold can be the gray value parameter in the XRT photoelectric separator. Using the gray value as the sorting threshold parameter can accurately screen out high-purity pre-selected concentrate.

[0043] It should be noted that when the separation threshold of photoelectric pretreatment is below 12800, the pre-selected concentrate obtained by photoelectric pretreatment will be mixed with some pre-selected tailings, resulting in a decrease in the grade of the final aluminum concentrate; when the separation threshold of photoelectric pretreatment is above 13200, the pre-selected tailings obtained by photoelectric pretreatment will be mixed with some pre-selected concentrate, resulting in a decrease in the yield of the final aluminum concentrate.

[0044] In some optional embodiments, the light source intensity of the photoelectric sorting pretreatment is 50kV to 70kV.

[0045] In these embodiments, photoelectric sorting pretreatment with a light source intensity of 50kV to 70kV can ensure that the X-rays in the photoelectric sorting pretreatment have sufficient energy to penetrate the coarse-grained raw ore, thereby improving the X-ray penetration and avoiding the coarse-grained raw ore particles being too large and affecting the X-ray penetration. This allows for accurate reflection of the pre-selected concentrate and pre-selected tailings of the coarse-grained raw ore, improving the sorting effect of photoelectric sorting pretreatment, and ultimately improving the grade of the subsequent aluminum concentrate.

[0046] The light source intensity for the photoelectric sorting pretreatment can be 50kV, 51kV, 52kV, 53kV, 54kV, 55kV, 60kV, 65kV or 70kV.

[0047] In some alternative embodiments, the photoelectric sorting pretreatment is performed by feeding in a vibratory manner, wherein the vibration frequency of the photoelectric sorting pretreatment is 30 Hz to 40 Hz.

[0048] In these embodiments, photoelectric separation pretreatment with a vibration frequency of 30Hz to 40Hz can ensure that the coarse-grained raw ore is evenly distributed during the photoelectric separation pretreatment stage, allowing the X-rays of the photoelectric separation pretreatment to fully penetrate the coarse-grained raw ore. This can accurately reflect the pre-selected concentrate and pre-selected tailings of the coarse-grained raw ore, improve the separation effect of photoelectric separation pretreatment, and ultimately improve the grade of the subsequent aluminum concentrate.

[0049] The vibration frequency of the photoelectric sorting pretreatment can be 30Hz, 31Hz, 32Hz, 33Hz, 34Hz, 35Hz or 40Hz.

[0050] In some alternative embodiments, the target particle size for the primary grading process is 3 mm to 3.5 mm; and / or The target particle size for the secondary grading process is 0.15 mm to 0.20 mm; and / or The particle size of the trihydrate gibbsite bauxite is ≤20mm.

[0051] In these embodiments, primary classification with a target particle size of 3mm to 3.5mm can separate gibbsite bauxite into coarse and fine-grained raw ore, avoiding the efficiency loss caused by "coarse-fine mixing" in gibbsite bauxite. Furthermore, secondary classification with a target particle size of 0.15mm to 0.20mm can effectively separate aluminum concentrate from the pre-selected tailings crushed material and the fine-grained raw ore, which is beneficial for improving the grade of the final aluminum concentrate. In addition, for gibbsite bauxite with a particle size ≤20mm, X-rays used in photoelectric separation pretreatment can fully penetrate the coarse-grained raw ore to accurately reflect the pre-selected concentrate and pre-selected tailings of the coarse-grained raw ore, improving the separation effect of photoelectric separation pretreatment and ultimately increasing the grade of the subsequent aluminum concentrate.

[0052] The target particle size for this primary grading process can be 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, or 3.5 mm.

[0053] The target particle size for this secondary classification process can be 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, or 0.20 mm.

[0054] In some alternative implementations, the first separation is carried out in a disturbed separation manner, the feed mass concentration of the first separation is 20% to 30%, and the water flow velocity of the first separation is 15 cm / s to 20 cm / s.

[0055] In these embodiments, the first sorting with a feed concentration of 20% to 30% and a water flow rate of 15 cm / s to 20 cm / s can accurately capture coarse-grained individual gibbsites in the coarse-grained processed ore and remove coarse-grained gangue minerals.

[0056] The feed concentration for the first sorting can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%.

[0057] The water flow velocity in the first sorting can be 15cm / s, 16cm / s, 17cm / s, 18cm / s, 19cm / s, or 20cm / s.

[0058] It should be noted that in the first separation process, the feed concentration determines the bed stability and bed density. If the feed concentration is too high, the collision between mineral particles in the coarse-grained ore will intensify, resulting in severe mechanical inclusions in the coarse-grained concentrate. If the feed concentration is too low, the bed density in the first separation will be difficult to maintain, making it easy for fine-grained impurities to be washed into the overflow with the rising water flow, thus affecting the separation effect of the first separation.

[0059] It should be noted that during the first sorting process, the water flow rate can control the particle separation effect of the coarse-grained ore. If the water flow rate is too high, high-density impurity minerals will be washed into the overflow, affecting the sorting effect. If the water flow rate is too low, some aluminum concentrate will settle too quickly, resulting in a low aluminum concentrate yield.

[0060] In some optional embodiments, the bed density of the first sorting is 1.9 g / cm³. 3 Up to 2.1 g / cm 3 The pressure difference of the bed in the first sorting is 8 kPa to 10 kPa.

[0061] In these embodiments, the bed density is 1.9 g / cm³. 3 Up to 2.1 g / cm 3 The first separation with a bed pressure difference of 8 kPa to 10 kPa can accurately capture coarse-grained individual gibbsite in coarse-grained processed ore and remove coarse-grained gangue minerals under specific feed mass concentration and water flow velocity conditions.

[0062] The bed density for this first sorting step can be 1.9 g / cm³. 3 1.95g / cm3 2.0g / cm 3 2.05g / cm 3 Or 2.10 g / cm 3 .

[0063] The bed pressure difference in the first sorting can be 8 kPa, 8.5 kPa, 9.0 kPa, 9.5 kPa, or 10.0 kPa.

[0064] It should be noted that in the first sorting process, the bed density affects the sorting effect. Therefore, the bed density can be adjusted according to the density difference between impurity minerals and target minerals in the coarse-grained ore. The bed pressure differential can shorten the sorting time and improve the stability of the first sorting process. Therefore, the bed pressure differential can be adjusted according to the first sorting requirements of impurity minerals and target minerals in the coarse-grained ore.

[0065] In some alternative embodiments, the second sorting is performed by centrifugal sorting at a rotation speed of 300 rpm to 450 rpm and a rinsing water flow rate of 600 L / h to 1000 L / h.

[0066] In these embodiments, the second sorting with a rotation speed of 300 rpm to 450 rpm and a rinsing water flow rate of 600 L / h to 1000 L / h can accurately separate fine-grained gibbsite from fine-grained gangue minerals and slime, preventing gangue minerals from being entrained in the aluminum concentrate.

[0067] The second sorting speed can be 300rpm, 310rpm, 320rpm, 330rpm, 340rpm, 350rpm, 400rpm, or 450rpm.

[0068] The rinsing water flow rate for the second sorting can be 600L / h, 650L / h, 700L / h, 750L / h, 800L / h, 850L / h, 900L / h, 950L / h, or 1000L / h.

[0069] It should be noted that the centrifugal concentrator used in this second separation process can employ an arc-shaped drum. Under the same conditions, the arc-shaped drum experiences greater centrifugal force than a straight drum, which can prevent impurities from mixing into the aluminum concentrate and maximize the grade of the aluminum concentrate. Furthermore, during the second separation process, the material that flows out first with the fluid is fine-grained aluminum concentrate, while the impurities adhering to the inner wall of the arc-shaped drum are fine-grained tailings.

[0070] In some alternative embodiments, the gibbsite bauxite includes gibbsite aluminum minerals, silica minerals, and iron minerals, wherein the silica minerals include at least one of kaolinite, illite, and pyrophyllite, and the iron minerals include goethite and / or hematite.

[0071] In these embodiments, the use of gibbsite-type bauxite, which includes gibbsite aluminum minerals, silica minerals and iron minerals, including at least one silica mineral among kaolinite, illite and pyrophyllite, and iron minerals including goethite and / or hematite, can cover most gibbsite-type bauxite, which is beneficial to improving the applicability of the separation method.

[0072] It should be noted that the gibbsite-type bauxite may include alumina, silica, and ferric oxide components, with the alumina component having a mass content of ≥40.00%, the silica component having a mass content of ≥10.00%, and the ferric oxide component having a mass content of ≥20%.

[0073] In some alternative embodiments, the components of the gibbsite bauxite include alumina and silicon dioxide, wherein the mass m1 of the alumina and the mass m2 of the silicon dioxide satisfy the following ratio: m1:m2 = (2.5 to 4.0):1.

[0074] In these embodiments, controlling the composition of gibbsite bauxite to include alumina and silica, and controlling the mass ratio of alumina to silica (2.5 to 4.0):1, can ensure that the gibbsite bauxite contains sufficient aluminum minerals, which is beneficial to improving the grade of subsequent aluminum concentrate.

[0075] The mass m1 of the alumina can be 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4.0.

[0076] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0077] Example 1 Gibbsite bauxite comprises alumina, silica, and ferric oxide components. The alumina component has a mass content of 41.35%, the silica component has a mass content of 12.68%, and the ferric oxide component has a mass content of 21.36%.

[0078] like Figure 1 As shown, a method for separating high-silicon-content gibbsite bauxite includes: S1. Perform a primary classification process on the trihydrate gibbsite-type bauxite to obtain coarse-grained raw ore and fine-grained raw ore; S2. The coarse-grained raw ore is subjected to photoelectric separation pretreatment to obtain pre-selected concentrate and pre-selected tailings; S3. Crush the pre-selected tailings to obtain pre-selected tailings crushed material; S4. The pre-selected tailings crushed material and fine-grained raw ore are sequentially combined and subjected to secondary classification to obtain coarse-grained processed ore and fine-grained processed ore. S5. Perform the first separation on the coarse-grained ore to obtain coarse-grained concentrate; S6. Perform a second separation on the fine-grained ore to obtain fine-grained concentrate; S7. Combine the pre-selected concentrate, coarse-grained concentrate, and fine-grained concentrate to obtain aluminum concentrate; S8. Combine the coarse-grained tailings to obtain separated tailings.

[0079] The sorting threshold for photoelectric sorting pretreatment is 13000.

[0080] The light source intensity for photoelectric sorting pretreatment is 60kV.

[0081] The photoelectric sorting pretreatment uses vibration to feed the material, and the vibration frequency of the photoelectric sorting pretreatment is 40Hz.

[0082] The target particle size for the first grading process is 3 mm. The target particle size for the secondary grading process is 0.15 mm; The particle size of trihydrate gibbsite bauxite is 20 mm.

[0083] The first separation is carried out by interference separation. The feed concentration for the first separation is 25%, and the water flow velocity for the first separation is 18 cm / s.

[0084] The bed density for the first sorting is 2 g / cm³. 3 The pressure difference of the bed in the first sorting is 8 kPa.

[0085] The second sorting is carried out by centrifugal sorting at a rotation speed of 370 rpm and a rinsing water flow rate of 700 L / h.

[0086] Gibbsite-type bauxite includes gibbsite aluminum minerals, silica minerals, and iron minerals. The silica minerals include kaolinite, illite, and pyrophyllite, while the iron minerals include goethite and hematite.

[0087] The components of trihydrate gibbsite bauxite include alumina and silicon dioxide, and the mass of alumina m1 and the mass of silicon dioxide m2 satisfy the following condition: m1:m2=3.26:1.

[0088] Example 2 Compared to Example 1, the differences in this example are as follows, while the rest are the same: In the gibbsite-type bauxite, the mass content of alumina is 40.19%, the mass content of silicon oxide is 13.54%, and the mass content of ferric oxide is 20.31%.

[0089] The sorting threshold for photoelectric sorting pretreatment is 13200.

[0090] The light source intensity for photoelectric sorting pretreatment is 50kV.

[0091] The photoelectric sorting pretreatment uses vibration to feed the material, and the vibration frequency of the photoelectric sorting pretreatment is 35Hz.

[0092] The feed concentration for the first separation is 20%, and the water flow velocity for the first separation is 15 cm / s.

[0093] The bed density for the first sorting stage is 1.9 g / cm³. 3 The pressure difference of the bed in the first sorting is 8 kPa.

[0094] The second sorting is carried out by centrifugal sorting at a rotation speed of 370 rpm and a rinsing water flow rate of 700 L / h.

[0095] The mass m1 of alumina and the mass m2 of silicon oxide satisfy the following ratio: m1:m2 = 2.97:1.

[0096] Example 3 Compared to Example 1, the differences in this example are as follows, while the rest are the same: In the gibbsite-type bauxite, the mass content of alumina is 42.21%, the mass content of silicon oxide is 12.17%, and the mass content of ferric oxide is 21.53%.

[0097] The sorting threshold for photoelectric sorting pretreatment is 13000.

[0098] The light source intensity for photoelectric sorting pretreatment is 60kV.

[0099] The photoelectric sorting pretreatment uses vibration to feed the material, and the vibration frequency of the photoelectric sorting pretreatment is 30Hz.

[0100] The first separation is carried out by interference separation. The feed concentration for the first separation is 20%, and the water flow velocity for the first separation is 15 cm / s.

[0101] The bed density for the first sorting stage is 2.0 g / cm³. 3 The pressure difference of the bed in the first sorting is 8 kPa.

[0102] The rotation speed of the second sorting is 400 rpm, and the rinsing water flow rate of the second sorting is 600 L / h.

[0103] The mass m1 of alumina and the mass m2 of silicon oxide satisfy the following ratio: m1:m2 = 3.47:1.

[0104] Example 4 Compared to Example 1, the differences in this example are as follows, while the rest are the same: In the gibbsite-type bauxite, the mass content of alumina is 40.78%, the mass content of silicon oxide is 13.22%, and the mass content of ferric oxide is 20.98%.

[0105] The sorting threshold for photoelectric sorting pretreatment is 12800.

[0106] The light source intensity for photoelectric sorting pretreatment is 70kV.

[0107] The vibration frequency of the photoelectric sorting pretreatment is 40Hz.

[0108] The feed concentration for the first separation is 25%, and the water flow velocity for the first separation is 18 cm / s.

[0109] The bed density for the first sorting stage is 2.0 g / cm³. 3 The pressure difference of the bed in the first sorting is 10 kPa.

[0110] The second sorting speed is 400 rpm, and the rinsing water flow rate for the second sorting is 600 L / h to 1000 L / h.

[0111] The mass m1 of alumina and the mass m2 of silicon oxide satisfy the following condition: m1:m2 = 3.08:1.

[0112] Example 5 Compared to Example 1, the differences in this example are as follows, while the rest are the same: In the gibbsite-type bauxite, the mass content of alumina is 41.89%, the mass content of silicon oxide is 11.29%, and the mass content of ferric oxide is 21.03%.

[0113] The sorting threshold for photoelectric sorting pretreatment is 13000.

[0114] The light source intensity for photoelectric sorting pretreatment is 60kV.

[0115] The vibration frequency of the photoelectric sorting pretreatment is 40Hz.

[0116] The feed concentration for the first separation is 25%, and the water flow velocity for the first separation is 20 cm / s.

[0117] The bed density for the first sorting stage is 2.1 g / cm³. 3 The pressure difference of the bed in the first sorting is 10 kPa.

[0118] The rotation speed of the second sorting is 320 rpm, and the rinsing water flow rate of the second sorting is 800 L / h.

[0119] The mass m1 of alumina and the mass m2 of silicon oxide satisfy the following condition: m1:m2 = 3.51:1.

[0120] Comparative Example 1 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The target particle size for the first grading process is 5 mm. The particle size of trihydrate gibbsite bauxite is 30 mm.

[0121] Comparative Example 2 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The target particle size for the first grading process is 5 mm. The target particle size for the secondary grading process is 0.5 mm.

[0122] Comparative Example 3 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The feed concentration for the first separation is 25%, and the water flow velocity for the first separation is 23 cm / s.

[0123] The bed density for the first sorting stage is 2.2 g / cm³. 3 The pressure difference of the bed in the first sorting is 12 kPa.

[0124] Comparative Example 4 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The feed concentration for the first sorting step is 35%.

[0125] Comparative Example 5 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The second sorting speed is 240 rpm.

[0126] Comparative Example 6 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The rinsing water flow rate for the second sorting is 400 L / h. Relevant experimental and effect data: Aluminum concentrates and tailings obtained from each embodiment and comparative example were collected, and the composition of these aluminum concentrates and tailings was determined. The results are shown in Table 1.

[0127] Table 1. Composition of aluminum concentrate and separated tailings in each embodiment and comparative example.

[0128] As shown in Table 1, the separation method for high-silicon-content gibbsite bauxite provided in this application systematically solves the pain points of poor adaptability of coarse and fine particle separation, severe gangue entrainment, and low separation efficiency in conventional gibbsite bauxite separation processes through three core logics: source pre-disposal of waste to improve grade, precise graded separation to control quality, and liberation degree optimization to ensure separation accuracy. Ultimately, it significantly improves the grade of aluminum concentrate.

[0129] Compared to Example 1, Comparative Example 1 increased the particle size of gibbsite bauxite and the target particle size for the first-stage classification process. This resulted in insufficient light intensity for the photoelectric separation pretreatment to penetrate the ore of gibbsite bauxite, causing some silica minerals in the gibbsite bauxite to be misidentified as aluminum minerals, thus affecting the separation effect of the photoelectric separation pretreatment. At the same time, due to the excessively large particle size of gibbsite bauxite, the degree of liberation of gibbsite bauxite was poor, affecting the separation effect of gibbsite bauxite.

[0130] Compared to Example 1, Comparative Example 2 increases the target particle size for both primary and secondary classification processes. This directly affects the separation index of coarse and fine-grained ore. Based on the complex intergrowth relationship of aluminum and silicon minerals in gibbsite-type bauxite and the characteristics of finer intergrowth particle size, the higher target particle size for classification processes results in insufficient mineral liberation during primary and secondary classification processes. Furthermore, the aluminum-silicon ratio of the tailings obtained from the first and second classification processes is relatively high, while the aluminum-silicon ratio of the aluminum concentrate is relatively low, directly affecting the grade of the aluminum concentrate.

[0131] Compared to Example 1, Comparative Example 3 uses a higher water flow velocity in the first separation process. The excessively high water flow velocity causes high-density fine mineral particles and medium-density mineral particles in the coarse-grained ore to be washed into the overflow of the first separation process. This directly affects the separation effect of the coarse-grained concentrate and the indicators of the final aluminum concentrate and the separated tailings. In addition, Comparative Example 3 uses a higher bed pressure difference in the first separation process, which increases the density of the minerals separated in the first separation process. This causes some silicon minerals to flow out from the overflow port, affecting the effect of the first separation process.

[0132] Compared to Example 1, Comparative Example 4 increases the feed mass concentration in the first separation process. This results in an excessive amount of solids entering the TBS interference bed, which affects the bed layer of the TBS interference bed, weakens its stability, reduces the separation accuracy of the first separation process, and exacerbates the interference between mineral particles in the TBS interference bed. This worsens the settling degree of mineral particles in the first separation process, leading to a decrease in the separation accuracy of the first separation process and affecting its separation effect.

[0133] Compared to Example 1, Comparative Example 5 increases the rotational speed of the centrifugal concentrator used in the second separation process. This increases the centrifugal force on some aluminum minerals in the fine-grained ore, causing some aluminum minerals to adhere to the drum wall of the centrifugal concentrator and be discharged from the outlet of the centrifugal concentrator, affecting the separation effect of the second separation.

[0134] Compared to Example 1, Comparative Example 6 increased the rinsing water flow rate, which caused some of the silicon minerals attached to the centrifugal concentrator used in the second sorting process to be washed out, affecting the sorting effect of the second sorting.

[0135] In summary, the present application provides a separation method for high-silicon-content gibbsite-type bauxite. This separation method, through a grade control closed loop of "pre-disposal of waste + grading + dissociation + precise sorting + product merging", strictly controls the mixing of gangue minerals in all aspects from the source, process, and end, and ultimately achieves a stable improvement in the grade of aluminum concentrate.

[0136] Furthermore, this application provides a method for separating high-silicon-content gibbsite-type bauxite. This method is based on a pre-treatment process involving primary classification and photoelectric separation, a mid-treatment process involving crushing and secondary classification, and further combined with gravity separation of the coarse-grained ore from the first separation and centrifugation of the fine-grained ore from the second separation. This yields a high-quality alumina concentrate with a high aluminum-to-silicon ratio and relatively low impurity content, as well as a reagent-free and neutral tailings. The alumina concentrate can be used as a raw material for Bayer process alumina production, while the tailings can be safely stockpiled or used as backfill material in mines.

[0137] Furthermore, this application provides a method for separating high-silicon-content gibbsite-type bauxite. This method has low operating costs, a simple process, and does not require the addition of any chemical reagents. It can effectively reduce the separation composition of low-grade bauxite, and the separated aluminum concentrate can be used as a high-grade alumina raw material. This effectively reduces the amount of red mud generated in the Bayer process of alumina production, thereby improving the resource utilization rate of bauxite and having significant implications for the sustainable development of the aluminum industry.

[0138] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for separating high-silicon-content gibbsite-type bauxite, characterized in that, The separation method includes: The trihydrate gibbsite type bauxite is subjected to a primary classification process to obtain coarse-grained raw ore and fine-grained raw ore. The coarse-grained raw ore is subjected to photoelectric separation pretreatment to obtain pre-selected concentrate and pre-selected tailings; The pre-selected tailings are crushed to obtain pre-selected tailings crushed material; The pre-selected tailings crushed material and the fine-grained raw ore are sequentially combined and subjected to secondary classification to obtain coarse-grained processed ore and fine-grained processed ore. The coarse-grained ore is first sorted to obtain coarse-grained concentrate; The fine-grained processed ore is subjected to a second sorting to obtain a fine-grained concentrate. The pre-selected concentrate, the coarse-grained concentrate, and the fine-grained concentrate are combined to obtain aluminum concentrate.

2. The separation method according to claim 1, characterized in that, The sorting threshold for the photoelectric sorting preprocessing is 12800 to 13200.

3. The separation method according to claim 1, characterized in that, The light source intensity for the photoelectric sorting pretreatment is 50kV to 70kV.

4. The separation method according to claim 1, characterized in that, The photoelectric sorting pretreatment is performed by feeding the material with vibration, and the vibration frequency of the photoelectric sorting pretreatment is 30Hz to 40Hz.

5. The separation method according to claim 1, characterized in that, The target particle size for the primary grading process is 3 mm to 3.5 mm; and / or The target particle size for the secondary grading process is 0.15 mm to 0.20 mm; and / or The particle size of the trihydrate gibbsite bauxite is ≤20mm.

6. The separation method according to claim 1, characterized in that, The first separation is carried out by interference separation, the feed mass concentration of the first separation is 20% to 30%, and the water flow velocity of the first separation is 15 cm / s to 20 cm / s.

7. The separation method according to claim 6, characterized in that, The density of the first sorting bed is 1.9 g / cm³. 3 Up to 2.1 g / cm 3 The pressure difference of the bed in the first sorting is 8 kPa to 10 kPa.

8. The separation method according to claim 1, characterized in that, The second sorting is carried out by centrifugal sorting, with a rotation speed of 300 rpm to 450 rpm and a rinsing water flow rate of 600 L / h to 1000 L / h.

9. The separation method according to claim 1, characterized in that, The gibbsite-type bauxite includes gibbsite aluminum minerals, silica minerals, and iron minerals. The silica minerals include at least one of kaolinite, illite, and pyrophyllite, and the iron minerals include goethite and / or hematite.

10. The separation method according to claim 1, characterized in that, The components of the trihydrate gibbsite bauxite include alumina and silicon dioxide, and the mass m1 of the alumina and the mass m2 of the silicon dioxide satisfy the following: m1:m2 = (2.5 to 4.0):1.

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