A method for desulfurization of fine fraction of high-sulfur bauxite

Abstract

The application provides a high-sulfur bauxite fine particle grade desulfurization method, and belongs to the bauxite beneficiation field. The method comprises the following steps: performing primary grinding on the high-sulfur bauxite to obtain a first ore slurry; performing one-stage flotation desulfurization on the first ore slurry to obtain an aluminum rough concentrate and a sulfur concentrate respectively; performing secondary grinding on the aluminum rough concentrate to obtain a second ore slurry; performing ultrasonic pretreatment on the second ore slurry to obtain a third ore slurry; and performing micro-bubble flotation on the third ore slurry to obtain an aluminum concentrate. The application performs ultrasonic pretreatment on the second ore slurry, the ultrasonic wave can remove the covering film or the oxidation layer on the surface of the fine particle grade mineral particles, reduces the negative influence of the free metal ions in the ore slurry on the flotation, and then the aluminum concentrate is obtained through micro-bubble flotation, thereby solving the fine particle grade flotation inclusion and realizing the micro-bubble flotation, improving the fine particle grade desulfurization effect, and realizing the comprehensive utilization of the high-sulfur bauxite resources.

Description

Technical Field

[0001] This application relates to the field of bauxite beneficiation technology, and in particular to a method for fine-grained desulfurization of high-sulfur bauxite. Background Technology

[0002] With the depletion of domestic bauxite resources and the advancement of resource exploration and mining technologies, the comprehensive utilization of deep bauxite resources has been put on the agenda. As the burial depth increases, the sulfur content of most deep bauxite resources rises sharply, reaching 6% or even higher. The prerequisite for desulfurization utilization of such resources is to achieve the dissociation of sulfur minerals. However, due to the uneven particle size and complex intercalation relationship of sulfur minerals in the ore, a large number of fine particles are generated after dissociation.

[0003] After dissociation, fine-grained minerals have a larger surface area and significantly increased surface energy, resulting in higher adsorption capacity for reagents. However, their selective adsorption is poor, making them prone to inclusion. Simultaneously, the small size of these fine-grained minerals reduces the likelihood of collisions with flotation bubbles, necessitating a reduction in bubble volume to increase contact probability. Existing desulfurization methods for high-sulfur bauxite often employ conventional flotation or a combination of gravity and flotation, which cannot address the severe inclusion problem caused by the large surface area of ​​fine-grained minerals. Conventional flotation machines rely on mechanical agitation, generally producing large bubbles that are ineffective for fine-grained flotation. Furthermore, the mineralizers in flotation columns and cells struggle to generate microbubbles. Therefore, a new flotation desulfurization technology for fine-grained high-sulfur bauxite is urgently needed to address inclusions in fine-grained flotation, achieve microbubble flotation, improve desulfurization efficiency, and realize the comprehensive utilization of high-sulfur bauxite resources. Summary of the Invention

[0004] This application provides a method for desulfurization of fine-grained high-sulfur bauxite to solve the following technical problem: how to improve the desulfurization effect of fine-grained high-sulfur bauxite.

[0005] This application provides a method for fine-grained desulfurization of high-sulfur bauxite, the method comprising:

[0006] The high-sulfur bauxite is ground once to obtain the first slurry;

[0007] The first slurry was subjected to a first-stage flotation desulfurization process to obtain aluminum crude concentrate and sulfur concentrate, respectively.

[0008] The aluminum concentrate is then subjected to secondary grinding to obtain a second slurry;

[0009] The second slurry is pretreated with ultrasound to obtain the third slurry; and

[0010] The third slurry was subjected to microbubble flotation to obtain aluminum concentrate.

[0011] Optionally, the power density of the ultrasonic pretreatment is 3 W / cm². 2 ~5W / cm2 The ultrasonic pretreatment time is 2 min to 10 min.

[0012] Optionally, in the second slurry, the number of particles with a diameter <0.038 mm accounts for ≥90% of the total number of particles in the second ore.

[0013] Optionally, the sulfur content of the aluminum concentrate is ≤0.5% by mass fraction.

[0014] Optionally, the sulfur concentrate has a sulfur content of ≥36% by mass fraction.

[0015] Optionally, the sulfur content of the high-sulfur bauxite is ≥6% by mass fraction.

[0016] Optionally, the microbubble flotation uses a driveless flotation cell with a microbubble mineralizer.

[0017] Optionally, the slurry delivery pressure in the microbubble mineralizer is 0.08 MPa to 0.50 MPa.

[0018] Optionally, the microbubble mineralizer includes:

[0019] Upper sealing cavity, lower sealing cavity, air inlet pipe, microporous tube, ceramic ring, sealing gasket, sealing baffle, O-ring; among which,

[0020] The upper and lower sealing cavities are connected by flanges and have built-in microporous tubes;

[0021] The sealing connection between the built-in microporous tube and the upper and lower sealing cavities includes a ceramic ring, a sealing gasket, and a sealing baffle.

[0022] The sealing element for the flange connection is an O-ring.

[0023] Optionally, the microporous tube is a straight tube or a Venturi tube, the porosity of the microporous tube is ≥70%, and the pore size of the microporous tube is 20μm to 150μm.

[0024] The technical solutions provided in this application have the following advantages compared with the prior art:

[0025] This application provides a method for fine-grained desulfurization of high-sulfur bauxite. First, the high-sulfur bauxite is ground once to obtain a first slurry, which is then subjected to a first-stage flotation desulfurization process to obtain alumina concentrate and sulfur concentrate, thereby preferentially removing coarse-grained sulfur minerals. Next, the alumina concentrate is ground a second time to obtain a second slurry, which further liberates the sulfur minerals in the fine-grained stage. Then, the second slurry is ultrasonically pretreated to obtain a third slurry. Ultrasonic pretreatment of the slurry removes the coating or oxide layer on the surface of the fine-grained mineral particles, reducing the negative impact of free metal ions in the slurry on flotation. Finally, the third slurry is subjected to microbubble flotation in a non-driven flotation cell to obtain the alumina concentrate. This method solves the problem of inclusions in fine-grained flotation and achieves microbubble flotation, improving the fine-grained desulfurization effect and realizing the comprehensive utilization of high-sulfur bauxite resources. Attached Figure Description

[0026] 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.

[0027] 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.

[0028] Figure 1 A schematic flowchart illustrating a method for fine-grained desulfurization of high-sulfur bauxite provided in this application embodiment;

[0029] Figure 2 This is a schematic diagram of the actual process of a method for fine-grained desulfurization of high-sulfur bauxite provided in an embodiment of this application;

[0030] Figure 3 This is a schematic diagram of the structure of the microbubble mineralizer provided in the embodiments of this application;

[0031] Figure label:

[0032] 1-Upper sealing cavity, 2-Lower sealing cavity, 3-Inlet pipe, 4-Microporous tube, 5-Ceramic ring, 6-Sealing gasket, 7-Sealing baffle, 8-O-ring seal. Detailed Implementation

[0033] 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.

[0034] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0035] Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts representation," such as parts by weight or parts by mass, indicates the proportional relationship between components. In the proportional relationships discussed in this article, parameters described by proportion should be understood as the first term of the proportion in the order of description, while the proportion figure should be understood as the second term. For example, if the mass ratio of substance A, substance B, and substance C is 1:2:3, then substances A, B, and C should correspond one-to-one with the proportion figure in the proportion in the order of description, i.e., the mass of substance A : the mass of substance B : the mass of substance C = 1:2:3.

[0036] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0037] Figure 1 A schematic flowchart illustrating a method for fine-grained desulfurization of high-sulfur bauxite provided in this application embodiment; Figure 2 This is a schematic diagram of the actual process of a method for fine-grained desulfurization of high-sulfur bauxite provided in an embodiment of this application.

[0038] like Figure 1 and Figure 2 As shown, this application provides a method for fine-grained desulfurization of high-sulfur bauxite, the method comprising:

[0039] S1. The high-sulfur bauxite is ground once to obtain the first slurry;

[0040] In some embodiments, the sulfur content of the high-sulfur bauxite is ≥6% by mass fraction.

[0041] Those skilled in the art will understand that the high-sulfur bauxite is buried deep underground, generally has a high sulfur content (≥6%), complex sulfur mineral intercalation, and often contains sulfur minerals with an intercalation particle size of less than 50 μm.

[0042] Those skilled in the art will understand that the primary grinding is a conventional grinding fineness determined based on the coarser particle size of the sulfur minerals embedded in the ore.

[0043] S2. The first slurry is subjected to a first-stage flotation desulfurization to obtain aluminum crude concentrate and sulfur concentrate, respectively.

[0044] A single flotation desulfurization process can preferentially remove coarse-grained sulfur minerals.

[0045] In some embodiments, the flotation desulfurization process includes one roughing, one or more cleaning processes, and one or more scavenging processes.

[0046] It is readily understood by those skilled in the art that multiple screenings are beneficial for enriching aluminum concentrate, and multiple scavengings are beneficial for enriching sulfur concentrate.

[0047] S3. The aluminum concentrate is subjected to secondary grinding to obtain a second slurry;

[0048] In some embodiments, the number of particles with a diameter <0.038 mm in the second slurry accounts for ≥90% of the total number of particles in the second ore.

[0049] Those skilled in the art will understand that the aluminum concentrate contains aluminum and sulfur minerals that are not easily liberated, therefore the second slurry needs to be ground to a finer overall particle size.

[0050] S4. The second slurry is subjected to ultrasonic pretreatment to obtain the third slurry; and

[0051] During ultrasonic pretreatment, ultrasonic waves can remove the coating or oxide layer on the surface of fine-grained mineral particles, reduce the negative impact of free metal ions in the slurry on flotation, and further separate aluminum and sulfur minerals in the fine particles.

[0052] In some embodiments, the power density of the ultrasonic pretreatment is 3 W / cm². 2 ~5W / cm 2 The ultrasonic pretreatment time is 2 min to 10 min.

[0053] Those skilled in the art will understand that ultrasonic pretreatment of slurry can remove the mineral coating and oxide layer on the surface of sulfur mineral particles, and reduce the amount of free metal ions (Fe) in the slurry. 3+ Ca 2+ Mg 2+To mitigate the negative impacts of ultrasonic pretreatment on flotation and improve flotation efficiency, a certain intensity and duration of oscillation cleaning are required. However, excessive intensity or prolonged cleaning time leads to energy waste. Therefore, limiting the power density and time of the ultrasonic pretreatment to the aforementioned range is beneficial for achieving optimal cleaning results and energy efficiency. For example, the power density of the ultrasonic pretreatment can be 3 W / cm². 2 3.5W / cm 2 4W / cm 2 4.5W / cm 2 4.8W / cm 2 5W / cm 2 The time for the ultrasonic pretreatment can be 2 min, 4 min, 6 min, 8 min, 9 min, 10 min, etc.

[0054] In some embodiments, the ultrasonic pretreatment equipment includes an ultrasonic oscillator, an ultrasonic industrial cleaning machine, an ultrasonic slurry pretreatment device, etc.

[0055] S5. The third slurry is subjected to microbubble flotation to obtain aluminum concentrate.

[0056] Those skilled in the art will understand that the primary / secondary flotation desulfurization requires conventional flotation desulfurization reagents such as pH adjusters, inhibitors, collectors, and frothers. Those skilled in the art will also understand that the ore from each stage of the primary / secondary flotation desulfurization process needs to be returned to the previous stage to form a closed-loop concentrator.

[0057] In some embodiments, the microbubble flotation uses a driveless flotation cell with a microbubble mineralizer.

[0058] Microbubble flotation combined with a dedicated microbubble mineralization flotation cell without transmission achieves effective removal of medium-sulfur minerals in fine particles. The sulfur content in aluminum concentrate can be reduced to below 0.5%, which can be used for alumina production. The sulfur concentrate can be used as a raw material for sulfuric acid production.

[0059] Those skilled in the art will understand that in some embodiments of this application, the driveless flotation cell is the bauxite settling flotation equipment described in Chinese Patent 201810687799.4. The main innovation of the embodiments of this application is the design of a microbubble mineralizer, which is more suitable for the flotation of fine particles.

[0060] Figure 3 This is a schematic diagram of the structure of the microbubble mineralizer provided in the embodiments of this application.

[0061] like Figure 3 As shown, in some embodiments, the microbubble mineralizer includes:

[0062] Upper sealing cavity 1, lower sealing cavity 2, air inlet pipe 3, microporous tube 4, ceramic ring 5, sealing gasket 6, sealing baffle 7, O-ring seal 8; among which,

[0063] The upper sealing cavity 1 and the lower sealing cavity 2 are connected by flanges and have built-in microporous tubes 4;

[0064] The sealing connection between the built-in microporous tube 4 and the upper sealing cavity 1 and the lower sealing cavity 2 includes a ceramic ring 5, a sealing gasket 6, and a sealing baffle 7.

[0065] The sealing element for the flange connection is an O-ring 8.

[0066] In some embodiments, the slurry delivery pressure in the microbubble mineralizer is 0.08 MPa to 0.50 MPa.

[0067] In some embodiments of this application, the mineralization process of the microbubble mineralizer includes: a. The slurry enters the inner hole of the microporous tube 4 through the upper flange of the upper sealing cavity 1 via a slurry pump, and the slurry delivery pressure is 0.08MPa to 0.50MPa; b. Air enters the outer cavity of the microporous tube 4 through the air inlet pipe 3, and after mixing with the slurry under air pressure or self-priming, microbubbles are generated and discharged through the lower flange outlet of the lower sealing cavity 2.

[0068] Those skilled in the art will understand that in some embodiments of this application, the microbubble mineralizer achieves the mixing of microbubbles and slurry. This includes conventional foam generation by directly injecting gas into the slurry at a pressure higher than the slurry pressure, and the use of a Venturi-type microporous tube to create a vacuum at the smallest orifice of the slurry, drawing in air from the external cavity. This reduces the air pressure requirement, and even allows for self-drawing when the slurry pressure is high, achieving energy savings and preventing clogging after slurry return. For example, the slurry delivery pressure can be 0.08 MPa, 0.10 MPa, 0.20 MPa, 0.30 MPa, 0.40 MPa, 0.50 MPa, etc.

[0069] In some embodiments, the microporous tube is a straight tube or a Venturi tube, the porosity of the microporous tube is ≥70%, and the pore size of the microporous tube is 20μm to 150μm.

[0070] The microbubble mineralizer of this application can adopt a venturi-type microporous tube, which can reduce the inlet air pressure and improve the phenomenon of slurry clogging the micropores, thereby achieving energy saving and extending the service life.

[0071] Those skilled in the art will understand that, in some embodiments of this application, the straight tube or Venturi microporous tube can be made of ceramic or organic polymer. Both straight tubes and Venturi microporous tubes can generate microbubbles, and both require a certain porosity to ensure sufficient gas flow. Simultaneously, the generation of microbubbles requires a small pore size. For example, the pore size can be 20, 30, 50, 80, 100, 120, 150 μm, etc. Regardless of the pore size, the porosity must be ≥70%, and can be 70%, 72%, 75%, 78%, 80%, 85%, etc.

[0072] In some embodiments, the sulfur content of the aluminum concentrate is ≤0.5% by mass fraction.

[0073] In some embodiments, the sulfur concentrate has a sulfur content of ≥36% by mass fraction.

[0074] Therefore, the embodiments of this application involve primary grinding of high-sulfur bauxite to obtain a first slurry, followed by a first-stage flotation desulfurization process to obtain alumina concentrate and sulfur concentrate, thereby preferentially removing coarse-grained sulfur minerals. The alumina concentrate is then subjected to secondary grinding to obtain a second slurry, which further liberates fine-grained sulfur minerals. The second slurry undergoes ultrasonic pretreatment to obtain a third slurry. Ultrasonic pretreatment removes the coating or oxide layer on the surface of fine-grained mineral particles, reducing the negative impact of free metal ions in the slurry on flotation. The third slurry is then subjected to microbubble flotation in a non-driven flotation cell to obtain alumina concentrate. The microbubble mineralizer of this application can employ a Venturi-type microporous tube to reduce inlet pressure and improve the phenomenon of slurry clogging micropores, achieving energy saving and extending the service life. The sulfur content in the alumina concentrate obtained by this application can be reduced to below 0.5%, making it suitable for alumina production, while the sulfur concentrate can be used as a raw material for sulfuric acid production. For example, the sulfur content of aluminum concentrate can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc., and the sulfur content of sulfur concentrate can be 36%, 37%, 38%, 39%, 40%, 41%, 42%, etc.

[0075] In summary, the desulfurization method for high-sulfur bauxite provided in this application has the following advantages:

[0076] (1) High-efficiency separation of fine-grained sulfur minerals: Through a two-stage grinding and flotation process, the first grinding preferentially removes coarse-grained sulfur minerals (embryophyll size > 50 μm), while the second grinding refines the aluminum concentrate into ultrafine particles (particle size < 0.038 mm, accounting for ≥ 90%), fully liberating fine-grained sulfur minerals (such as gypsum and pyrite), solving the problem of traditional single grinding being unable to handle micro-embryophyllized sulfur minerals (< 50 μm). Combined with ultrasonic pretreatment, the oxide layer and metal ions (Fe3+, Ca2+) on the mineral surface are removed. 2Interference such as + exposes the fresh surface of sulfur minerals, thereby improving the selectivity of subsequent flotation.

[0077] (2) Process synergy reduces sulfur content to industrial standards: By employing a multi-stage flotation process of "roughing-cleaning-scavenging" combined with microbubble flotation technology, the sulfur content of aluminum concentrate is stably ≤0.5%, meeting the requirements of Bayer process alumina production; the sulfur content of sulfur concentrate is ≥35%, which can be directly used as sulfuric acid feedstock, achieving comprehensive resource recovery. Compared with traditional flotation, this method significantly breaks through the bottleneck of sulfur removal through process optimization.

[0078] (3) Energy saving and equipment innovation: The Venturi microporous tube is adopted, which utilizes the self-priming vacuum of the slurry to reduce the air intake pressure, avoids backflow blockage, and extends the equipment life. The energy consumption is lower than that of traditional flotation machines. At the same time, the equipment structure is simplified, reducing mechanical wear and maintenance costs.

[0079] (4) Significant environmental and economic benefits: Ultrasonic pretreatment reduces the interference of free metal ions on flotation reagents and reduces the amount of collectors (such as xanthates) used. At the same time, high-grade sulfur concentrate (≥35%) can be sold as a by-product to offset desulfurization costs and improve overall economic efficiency.

[0080] (5) Adapting to complex ore characteristics: In response to the characteristics of high sulfur content and complex intercalation of high sulfur bauxite, the step-by-step separation and sorting (coarse first and fine, sulfur first and aluminum first) adapts to the ore dispersion and mineral symbiosis relationship, which is especially suitable for ore deposits with deep burial and discontinuous ore layers.

[0081] (6) Synergistic enhancement of ultrasound and microbubbles: Ultrasonic cleaning improves the floatability of mineral surfaces, while microbubbles enhance the adsorption efficiency of fine minerals and bubbles. The combination of the two breaks through the traditional flotation limit for fine particles.

[0082] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0083] Example 1

[0084] This embodiment provides a method for fine-grained desulfurization of high-sulfur bauxite, including the following steps:

[0085] Sa: High-sulfur bauxite with a sulfur content of 7.42% is ground once to obtain the first slurry, which is then subjected to "one roughing, two cleaning, and three scavenging" to obtain aluminum rough concentrate and sulfur concentrate;

[0086] Sb: The aluminum concentrate obtained from Sa is subjected to secondary grinding, and the fineness of the second slurry is -0.038mm, accounting for 91.23%;

[0087] Sc: The second slurry obtained from Sb was pretreated using an ultrasonic oscillator with a power density of 3 W / cm³. 2 The third slurry was obtained in 3 minutes;

[0088] Sd: The third slurry obtained from Sc is subjected to microbubble flotation in a non-driven flotation cell to obtain aluminum concentrate, wherein the slurry pressure of the microporous mineralizer is 0.14 MPa and the air pressure is 0.08 MPa.

[0089] During the flotation process, the ore was returned step by step from each operation, ultimately yielding an aluminum concentrate with a yield of 81.71% and a sulfur content of 0.43%, and a sulfur concentrate with a yield of 18.29% and a sulfur content of 38.65%.

[0090] Example 2

[0091] This embodiment provides a method for fine-grained desulfurization of high-sulfur bauxite, including the following steps:

[0092] Sa: High-sulfur bauxite with a sulfur content of 7.42% is ground once to obtain the first slurry, which is then subjected to "one roughing, two cleaning, and two scavenging" to obtain aluminum rough concentrate and sulfur concentrate;

[0093] Sb: The aluminum concentrate obtained from Sa is subjected to secondary grinding, and the fineness of the second slurry is -0.038mm, accounting for 95.41%;

[0094] Sc: The second slurry obtained from Sb was pretreated using an ultrasonic oscillator with a power density of 4 W / cm³. 2 The third slurry was obtained in 2 minutes;

[0095] Sd: The third slurry obtained from Sc is subjected to microbubble flotation in a non-driven flotation cell to obtain aluminum concentrate. The slurry pressure of the microporous mineralizer is 0.32 MPa, and the air is self-absorbed.

[0096] During the flotation process, the ore was returned step by step from each operation, ultimately yielding an aluminum concentrate with a yield of 81.86% and a sulfur content of 0.37%, and a sulfur concentrate with a yield of 18.14% and a sulfur content of 39.24%.

[0097] Example 3

[0098] This embodiment provides a method for fine-grained desulfurization of high-sulfur bauxite, including the following steps:

[0099] Sa: High-sulfur bauxite with a sulfur content of 8.44% is ground once to obtain the first slurry, which is then subjected to "one roughing, two cleaning, and three scavenging" to obtain aluminum rough concentrate and sulfur concentrate;

[0100] Sb: The aluminum concentrate obtained from Sa is subjected to secondary grinding, and the fineness of the second slurry is -0.038mm, accounting for 93.29%;

[0101] Sc: The second slurry obtained from Sb was pretreated using an ultrasonic oscillator with a power density of 4 W / cm³. 2 The third slurry was obtained in 3 minutes;

[0102] Sd: The third slurry obtained from Sc is subjected to microbubble flotation in a non-driven flotation cell to obtain aluminum concentrate, wherein the slurry pressure of the microporous mineralizer is 0.2MPa and the air pressure is 0.1MPa.

[0103] During the flotation process, the ore was returned step by step from each operation, ultimately yielding an aluminum concentrate with a yield of 78.98% and a sulfur content of 0.39%, and a sulfur concentrate with a yield of 21.02% and a sulfur content of 38.69%.

[0104] Example 4

[0105] This embodiment provides a method for fine-grained desulfurization of high-sulfur bauxite, including the following steps:

[0106] Sa: High-sulfur bauxite with a sulfur content of 9.49% is ground once to obtain the first slurry, which is then subjected to "one roughing, two cleaning, and three scavenging" to obtain aluminum rough concentrate and sulfur concentrate;

[0107] Sb: The aluminum concentrate obtained from Sa is subjected to secondary grinding, and the fineness of the second pulp is -0.038mm, accounting for 94.53%;

[0108] Sc: The second slurry obtained from Sb was pretreated using an ultrasonic oscillator with a power density of 3 W / cm³. 2 The third slurry was obtained in 7 minutes;

[0109] Sd: The third slurry obtained from Sc is subjected to microbubble flotation in a non-driven flotation cell to obtain aluminum concentrate, wherein the slurry pressure of the microporous mineralizer is 0.15MPa and the air pressure is 0.12MPa.

[0110] During the flotation process, the ore was returned step by step from each operation, ultimately yielding an aluminum concentrate with a yield of 77.24% and a sulfur content of 0.44%, and a sulfur concentrate with a yield of 22.76% and a sulfur content of 40.21%.

[0111] Example 5

[0112] This embodiment provides a method for fine-grained desulfurization of high-sulfur bauxite, including the following steps:

[0113] Sa: High-sulfur bauxite with a sulfur content of 14.53% is ground once to obtain the first slurry, which is then subjected to "one roughing, two cleaning, and three scavenging" to obtain aluminum rough concentrate and sulfur concentrate.

[0114] Sb: The aluminum concentrate obtained from Sa is subjected to secondary grinding, and the fineness of the second slurry is -0.038mm, accounting for 96.33%;

[0115] Sc: The second slurry obtained from Sb was pretreated using an ultrasonic oscillator with a power density of 5 W / cm³. 2 The third slurry was obtained after 5 minutes;

[0116] Sd: The third slurry obtained from Sc is subjected to microbubble flotation in a non-driven flotation cell to obtain aluminum concentrate, wherein the slurry pressure of the microporous mineralizer is 0.35MPa and the air pressure is 0.15MPa.

[0117] During the flotation process, the ore was returned step by step from each operation, ultimately yielding an aluminum concentrate with a yield of 65.61% and a sulfur content of 0.47%, and a sulfur concentrate with a yield of 34.39% and a sulfur content of 41.35%.

[0118] Comparative Example 1

[0119] The difference between this comparative example and Example 1 is that the ultrasonic pretreatment step was omitted, while the rest were the same. The final yield of aluminum concentrate was 80.02% with a sulfur content of 0.72%, and the yield of sulfur concentrate was 19.98% with a sulfur content of 34.26%.

[0120] Comparative Example 2

[0121] The difference between this comparative example and Example 1 is that the Sd step was not mineralized by a microbubble mineralizer and was followed by flotation in a non-drive flotation cell. The other steps were the same, and the final yield of aluminum concentrate was 78.56% with a sulfur content of 0.68%, and sulfur concentrate yield was 21.44% with a sulfur content of 32.11%.

[0122] Comparative Example 3

[0123] This comparative example adopts a flotation desulfurization method for high-sulfur bauxite disclosed in Chinese patent CN201310228614.0. Sedimentary high-sulfur bauxite with a sulfur content of 7.42% is ground, and the fineness of the grinding product is -0.074mm, accounting for 76.39%. The pH of the grinding product is adjusted to 8 with lime. After closed-circuit flotation desulfurization through "one roughing, three scavenging, and three cleaning", the yield of aluminum concentrate is 77.95% with sulfur content of 0.93%, and the yield of sulfur concentrate is 22.05% with sulfur content of 30.36%.

[0124] Comparative Example 4

[0125] This comparative example, Chinese patent CN201910444464.4, discloses a method for combined gravity flotation desulfurization of high-sulfur bauxite. For sedimentary high-sulfur bauxite with a sulfur content of 7.42%, and a grinding product fineness of -0.074 mm accounting for 76.39%, a shaking table is used for gravity separation desulfurization of the high-sulfur bauxite slurry. The shaking table uses a table inclination angle of 2.5°, a stroke of 11 mm, and a stroke rate of 250 times / min, yielding gravity-separated sulfur concentrate and gravity-separated aluminum concentrate. The resulting gravity-separated aluminum concentrate... Desulfurization was carried out directly using a non-driven flotation cell. The pH of the pulp was adjusted to 9.0 using a pH adjuster, followed by the addition of a collector, frother, activator, and depressant. The flotation desulfurization process consisted of one roughing, three cleaning, and three scavenging stages. The flotation aluminum concentrate obtained was the final aluminum concentrate, with a yield of 79.22% and a sulfur content of 0.61%. The flotation sulfur concentrate obtained was combined with the gravity sulfur concentrate obtained from gravity separation to form a composite sulfur concentrate, with a yield of 20.78% and a sulfur content of 33.38%.

[0126] Comparative Example 5

[0127] This comparative example, Chinese patent CN201910444464.4, discloses a method for combined gravity flotation desulfurization of high-sulfur bauxite. For sedimentary high-sulfur bauxite with a sulfur content of 9.49%, and a grinding product fineness of -0.074mm accounting for 80.21%, a shaking table is used for gravity separation desulfurization of the high-sulfur bauxite slurry. The shaking table has a table inclination angle of 2.5°, a stroke of 11mm, and a stroke rate of 250 times / min, yielding gravity-separated sulfur concentrate and gravity-separated aluminum concentrate. The obtained gravity-separated aluminum concentrate is then... Desulfurization was carried out directly using a non-driven flotation cell. The pH of the pulp was adjusted to 9.0 using a pH adjuster, followed by the addition of a collector, frother, activator, and depressant. The flotation desulfurization process consisted of one roughing, three cleaning, and three scavenging stages. The flotation aluminum concentrate obtained was the final aluminum concentrate, with a yield of 73.76% and a sulfur content of 0.68%. The flotation sulfur concentrate obtained was combined with the gravity pyrite concentrate obtained from gravity separation to form a composite sulfur concentrate, with a yield of 26.24% and a sulfur content of 34.25%.

[0128] The operational indicators and results of Examples 1-5 and Comparative Examples 1-5 are shown in Table 1:

[0129] Table 1. Operational indicators and results for Examples 1-5 and Comparative Examples 1-5

[0130]

[0131]

[0132] As can be seen from Table 1, all five examples using the technical implementation scheme of the present invention can achieve a sulfur content of ≤0.5% in aluminum concentrate and ≥36% in sulfur concentrate. A comparison of Examples 1 and 2 with Comparative Examples 1, 2, 3, and 4, and a comparison of Example 4 with Comparative Example 5, shows that under the same sulfur content conditions, the combined gravity flotation desulfurization effect is better than direct desulfurization. However, because sedimentary high-sulfur bauxite generally has a finer particle size, the sulfur content of the aluminum concentrate after gravity separation desulfurization is still relatively high, showing a significant difference compared to the examples. The desulfurization effect on fine particles is not as good as the implementation scheme of this technology.

[0133] Furthermore, one or more technical solutions in the embodiments of this application have at least the following technical effects or advantages:

[0134] In the embodiments of this application, the sulfur content of aluminum concentrate is ≤0.5%, and the sulfur content of sulfur concentrate is ≥36%.

[0135] This application embodiment solves the technical problem of fine-grained flotation inclusions in high-sulfur bauxite and achieves microbubble flotation. The sulfur content in the obtained bauxite concentrate can be reduced to below 0.5%, which can be used for alumina production. The sulfur concentrate can be used as a raw material for sulfuric acid production. It can provide technical support for domestic high-sulfur bauxite resources with fine intercalated particles and has broad application prospects.

[0136] 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 herein.

Claims

1. A method for fine-grained desulfurization of high-sulfur bauxite, the method comprising: The high-sulfur bauxite is ground once to obtain the first slurry; The first slurry was subjected to a first-stage flotation desulfurization process to obtain aluminum crude concentrate and sulfur concentrate, respectively. The aluminum concentrate is then subjected to secondary grinding to obtain a second slurry; The second slurry was pretreated with ultrasound to obtain the third slurry; as well as The third slurry was subjected to microbubble flotation to obtain aluminum concentrate; The power density of the ultrasonic pretreatment is 3 W / cm². 2 ~5W / cm 2 The ultrasonic pretreatment time is 2 min to 10 min; The microbubble flotation uses a driveless flotation cell with a microbubble mineralizer; The slurry delivery pressure in the microbubble mineralizer is 0.08 MPa to 0.50 MPa; The microbubble mineralizer includes: Upper sealing cavity (1), lower sealing cavity (2), air inlet pipe (3), microporous tube (4), ceramic ring (5), sealing gasket (6), sealing baffle (7), O-ring seal (8); among which, The upper sealing cavity (1) and the lower sealing cavity (2) are connected by flanges and have built-in microporous tubes (4); The sealing connection between the built-in microporous tube (4) and the upper sealing cavity (1) and the lower sealing cavity (2) includes a ceramic ring (5), a sealing gasket (6), and a sealing baffle (7); The sealing element for the flange connection is an O-ring (8); The microporous tube (4) is a straight tube or a Venturi tube, the porosity of the microporous tube (4) is ≥70%, and the pore size of the microporous tube (4) is 20μm~150μm.

2. The method according to claim 1, characterized in that, In the second slurry, the number of particles with a diameter <0.038 mm accounts for ≥90% of the total number of particles in the second slurry.

3. The method according to claim 1, characterized in that, The sulfur content of the aluminum concentrate is ≤0.5% by mass fraction.

4. The method according to claim 1, characterized in that, The sulfur content of the sulfur concentrate is ≥36% by mass fraction.

5. The method according to claim 1, characterized in that, The sulfur content of the high-sulfur bauxite is ≥6% by mass fraction.

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