Method for fine-fraction desulfurization of high-sulfur bauxite

Abstract

The invention provides a fine-fraction desulfurization method for high-sulfur bauxite, and belongs to the field of bauxite beneficiation. The method comprises the steps that the high-sulfur bauxite is subjected to primary ore grinding, and first ore pulp is obtained; the first ore pulp is subjected to first-section flotation desulfurization, and aluminum rough concentrate and sulfur concentrate are obtained respectively; the aluminum rough concentrate is subjected to secondary ore grinding, and second ore pulp is obtained; performing ultrasonic pretreatment on the second ore pulp to obtain third ore pulp; and the third ore pulp is subjected to microbubble flotation to obtain aluminum concentrate. According to the method, the second ore pulp is subjected to ultrasonic pretreatment, the ore pulp is pretreated through ultrasonic waves, covering films or oxide layers on the surfaces of fine-fraction mineral particles can be removed, the negative influence of free metal ions in the ore pulp on flotation is reduced, then the aluminum concentrate is obtained through microbubble flotation, and therefore the problem of fine-fraction flotation inclusion is solved, microbubble flotation is achieved, and the flotation efficiency is improved. The fine-fraction desulfurization effect is improved, and the comprehensive utilization of high-sulfur bauxite resources is realized.

Description

Technical Field

[0001] The present application relates to the technical field of bauxite beneficiation, and in particular to a method for desulfurization of fine-grained high-sulfur bauxite. Background Art

[0002] With the reduction of domestic bauxite resources and the advancement of resource exploration and mining technology, the comprehensive utilization of deep bauxite resources has been put on the agenda. With the increase of underground depth, the sulfur content of most deep bauxite resources increases sharply, reaching 6% or even higher. The premise of desulfurization and utilization of such resources is to achieve the dissociation of sulfur minerals. However, due to the uneven particle size and complex distribution relationship of sulfur minerals in the ore, more fine particles are produced after dissociation.

[0003] The surface energy of the dissociated fine-grained minerals increases significantly due to their large surface area, and they have a high adsorption capacity for the reagents, but their selective adsorption is poor and they are easily mixed; at the same time, the volume of fine-grained minerals is small, and the possibility of collision with flotation bubbles is small, so the volume of bubbles needs to be reduced to increase the contact probability. The existing high-sulfur bauxite desulfurization methods mostly use conventional flotation desulfurization methods or refloatation combined methods, which cannot solve the problem of serious inclusions caused by the large surface area of ​​fine particles; conventional flotation machines rely on mechanical stirring, and generally have large bubbles, and the flotation effect on fine particles is not good; the mineralizer of the flotation column and flotation cell is difficult to produce microbubbles. Therefore, there is an urgent need for a high-sulfur bauxite fine-grained flotation desulfurization technology to solve the problem of fine-grained flotation inclusions and realize microbubble flotation, improve the desulfurization effect of fine particles, and realize the comprehensive utilization of high-sulfur bauxite resources. Summary of the invention

[0004] The present 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] The present application provides a method for fine-grained desulfurization of high-sulfur bauxite, the method comprising:

[0006] Grinding the high-sulfur bauxite once to obtain a first slurry;

[0007] The first slurry is subjected to a first stage of flotation desulfurization to obtain a rough aluminum concentrate and a sulfur concentrate respectively;

[0008] Grinding the aluminum coarse concentrate for the second time to obtain a second slurry;

[0009] subjecting the second slurry to ultrasonic pretreatment to obtain a third slurry; and

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

[0011] Optionally, the power density of the ultrasonic pretreatment is 3W / cm 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 particle size of less than 0.038 mm accounts for ≥90% of the total number of particles of the second mineral material.

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

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

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

[0016] Optionally, the microbubble flotation uses a transmission-free 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 comprises:

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

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

[0021] The sealing connectors between the built-in microporous tube and the upper sealing cavity and the lower sealing cavity include a ceramic ring, a sealing gasket, and a sealing baffle;

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

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

[0024] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0025] The embodiment of the present application provides a method for fine-grained desulfurization of high-sulfur bauxite, firstly grinding the high-sulfur bauxite once to obtain a first pulp, and then flotation desulfurization to obtain aluminum coarse concentrate and sulfur concentrate, thereby preferentially removing sulfur minerals with coarse embedded particle size; secondly grinding the aluminum coarse concentrate twice to obtain a second pulp, which can further realize the dissociation of sulfur minerals in the fine-grained grade; ultrasonic pretreatment of the second pulp again to obtain a third pulp, and ultrasonic pretreatment of the pulp can remove the covering film or oxide layer on the surface of fine-grained mineral particles, and reduce the negative impact of free metal ions in the pulp on flotation; finally, the third pulp is subjected to microbubble flotation using a non-transmission flotation cell to obtain aluminum concentrate. In this way, the problem of fine-grained flotation inclusion is solved and microbubble flotation is realized, the fine-grained desulfurization effect is improved, and the comprehensive utilization of high-sulfur bauxite resources is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the description, are used to explain the principles of the present application.

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1 A schematic flow chart of a method for fine-grained desulfurization of high-sulfur bauxite provided in an embodiment of the present application;

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

[0030] Figure 3 A schematic diagram of the structure of a microbubble mineralizer provided in an embodiment of the present application;

[0031] Reference numerals:

[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. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0034] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0035] In addition, in the description of the specification of the present application, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second", etc. are only used 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 article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "the following at least one item (items)" or similar expressions refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple. "Parts" such as parts by weight and parts by mass indicate the proportional relationship between the components. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, the mass ratio of substance A, substance B, and substance C is 1:2:3, then substance A, substance B, and substance C should correspond one-to-one with the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0036] Unless otherwise specified, various 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 flow chart of a method for fine-grained desulfurization of high-sulfur bauxite provided in an embodiment of the present application; Figure 2 A schematic diagram of the actual process of a method for fine-grade desulfurization of high-sulfur bauxite provided in an embodiment of the present application.

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

[0039] S1, grinding the high-sulfur bauxite once to obtain a first slurry;

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

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

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

[0043] S2, subjecting the first slurry to a flotation desulfurization step to obtain a rough aluminum concentrate and a sulfur concentrate;

[0044] Through the first stage flotation desulfurization, the sulfur minerals with coarse embedded particle size can be removed preferentially.

[0045] In some embodiments, the one-stage flotation desulfurization process includes one roughing step, one or multiple cleaning steps, and one or multiple scavenging steps.

[0046] It is easy for those skilled in the art to understand that multiple concentrations are beneficial to enriching aluminum concentrate, and multiple scavengings are beneficial to enriching sulfur concentrate.

[0047] S3, grinding the aluminum coarse concentrate for a second time to obtain a second slurry;

[0048] In some embodiments, in the second slurry, the number of particles with a particle size of less than 0.038 mm accounts for ≥90% of the total number of particles of the second mineral material.

[0049] Those skilled in the art will appreciate that the aluminum rough concentrate contains aluminum minerals and sulfur minerals that are not easily dissociated, so the second slurry needs to be ground to a level with a relatively fine overall particle size.

[0050] S4, subjecting the second slurry to ultrasonic pretreatment to obtain a third slurry; and

[0051] During the ultrasonic pretreatment process, ultrasonic pretreatment of the pulp can remove the covering film or oxide layer on the surface of fine-grained mineral particles, reduce the negative impact of free metal ions in the pulp on flotation, and further sort the aluminum and sulfur minerals in the fine-grained particles.

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

[0053] It will be understood by those skilled in the art that ultrasonic pretreatment of the slurry can remove the mineral covering film and oxide layer on the surface of the sulfur mineral particles, reduce the free metal ions (Fe 3+ , Ca 2+ Mg 2+The negative impact of ultrasonic pretreatment on flotation, etc., is reduced, thereby improving the flotation effect. A certain oscillation cleaning intensity and corresponding time are required. However, if the intensity is too high or the cleaning time is too long, there will be a waste of energy consumption. Therefore, limiting the power density and time of the ultrasonic pretreatment to the above range is conducive to achieving the best cleaning effect and energy efficiency. For example, the power density of the ultrasonic pretreatment can be 3W / cm 2 、3.5W / cm 2 , 4W / cm 2 , 4.5W / cm 2 , 4.8W / cm 2 , 5W / cm 2 The ultrasonic pretreatment time 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 equipment, and the like.

[0055] S5. Performing microbubble flotation on the third slurry to obtain aluminum concentrate.

[0056] Those skilled in the art can understand that the first-stage / second-stage flotation desulfurization requires conventional flotation desulfurization agents such as pH adjusters, inhibitors, collectors, and frothers. Those skilled in the art can understand that the flotation ore from each operation of the first-stage / second-stage flotation desulfurization needs to be returned to the previous operation to form a closed-circuit mineral processing.

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

[0058] Microbubble flotation combined with the exclusive microbubble mineralization non-transmission flotation tank flotation achieves the effective removal of sulfur minerals in the fine-grained grade. The sulfur content in the aluminum concentrate can be reduced to below 0.5%, which can be used for alumina production, and the sulfur concentrate can be used as a raw material for sulfuric acid production.

[0059] Those skilled in the art can understand that in some embodiments of the present application, the transmission-free flotation cell is the bauxite sedimentation flotation equipment described in Chinese Patent 201810687799.4. The main innovation of the embodiments of the present application is the design of a microbubble mineralizer, which is more suitable for fine particle flotation.

[0060] Figure 3 This is a schematic diagram of the structure of the microbubble mineralizer provided in an embodiment of the present application.

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

[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 8; wherein,

[0063] The upper sealed cavity 1 and the lower sealed cavity 2 are connected by flanges and have a microporous tube 4 built in;

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

[0065] The sealing element of 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 the present application, the mineralization process of the microbubble mineralizer includes: a. the slurry enters the inner hole of the microporous tube 4 from the upper flange of the upper sealed cavity 1 through a slurry pump, and the slurry delivery pressure is 0.08MPa~0.50MPa; b. air enters the external cavity of the microporous tube 4 through the air inlet pipe 3, and after mixing with the slurry under the action of air pressure or self-priming, microbubbles are generated and discharged through the lower flange outlet of the lower sealed cavity 2.

[0068] Those skilled in the art will appreciate that in some embodiments of the present application, the microbubble mineralizer achieves mixing of microbubbles and slurry. It includes conventional foam generation by directly pressing gas into the slurry through a pressure higher than the slurry pressure, and by using a venturi-type microporous tube, a vacuum will be generated at the slurry passing through the smallest tube hole, sucking in the air of the external cavity, reducing the air pressure requirement, and even self-priming when the slurry pressure is high, which can achieve energy saving and avoid clogging after returning to the slurry. Exemplary, the slurry delivery pressure can be 0.08MPa, 0.10MPa, 0.20MPa, 0.30MPa, 0.40MPa, 0.50MPa, etc.

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

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

[0071] Those skilled in the art will appreciate that in some embodiments of the present application, the material of the straight tube or the venturi-type microporous tube can be ceramic material or organic polymer material. Both the straight tube and the venturi-type microporous tube can achieve microbubble generation, and both must have a certain porosity to ensure sufficient gas volume. At the same time, a smaller pore size is required to generate microbubbles. Exemplarily, 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 the porosity 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.

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

[0074] It can be seen that the embodiment of the present application grinds the high-sulfur bauxite once to obtain the first pulp, and obtains the aluminum coarse concentrate and the sulfur concentrate through a flotation desulfurization, thereby preferentially removing the sulfur minerals with coarse embedded particle size; grinds the aluminum coarse concentrate twice to obtain the second pulp, which can further realize the dissociation of sulfur minerals in the fine particle size; ultrasonic pretreatment is performed on the second pulp to obtain the third pulp, and ultrasonic pretreatment of the pulp can remove the covering film or oxide layer on the surface of the fine-grained mineral particles, reducing the negative impact of free metal ions in the pulp on flotation; the third pulp is subjected to microbubble flotation using a non-transmission flotation cell to obtain aluminum concentrate, and the microbubble mineralizer of the present application can use a Venturi-type microporous tube to reduce the intake pressure and improve the phenomenon of pulp blocking micropores, thereby achieving energy saving and extending the service life. The sulfur content in the aluminum concentrate obtained by the present application can be reduced to below 0.5%, which can be used for alumina production, and the sulfur concentrate can be used as a raw material for sulfuric acid production. Illustratively, the sulfur content of the 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 the sulfur concentrate can be 36%, 37%, 38%, 39%, 40%, 41%, 42%, etc.

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

[0076] (1) Efficient separation of fine-grained sulfur minerals: Through two grinding processes combined with flotation, the first grinding preferentially removes coarse sulfur minerals (embedded particle size > 50μm), and the second grinding refines the aluminum concentrate into ultra-fine particles (particle size < 0.038mm, accounting for ≥ 90%), fully dissociating fine sulfur minerals (such as gypsum and pyrite), solving the problem that traditional single grinding is difficult to process fine embedded sulfur minerals (< 50μm). Combined with ultrasonic pretreatment, the surface oxide layer and metal ions (Fe3+, Ca 2+, etc.), exposing the fresh surface of sulfur minerals and improving the subsequent flotation selectivity.

[0077] (2) Process synergy reduces sulfur content to industrial standards: The "roughing-cleaning-scavenging" multi-stage flotation and micro-bubble flotation technology are used in synergy, and the sulfur content of aluminum concentrate is stable at ≤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 raw material to achieve 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: Venturi microporous tubes are used to reduce the air intake pressure by using the slurry self-absorption vacuum, avoid slurry blockage, extend the equipment life, and reduce energy consumption compared to traditional flotation machines. At the same time, the equipment structure is simplified to reduce 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 xanthate). At the same time, high-grade sulfur concentrate (≥35%) can be sold as a by-product, offsetting the cost of desulfurization and improving overall economic efficiency.

[0080] (5) Adapting to complex ore characteristics: In view of the high sulfur content and complex distribution of high-sulfur bauxite, the ore dispersion and mineral symbiosis can be adapted through step-by-step dissociation and sorting (first coarse then fine, first sulfur then aluminum), which is particularly suitable for deep buried deposits with discontinuous ore layers.

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

[0082] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.

[0083] Example 1

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

[0085] Sa: Grind the high-sulfur bauxite with a sulfur content of 7.42% once to obtain the first pulp, and then obtain aluminum rough concentrate and sulfur concentrate through "one roughing, two cleaning and three scavenging";

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

[0087] Sc: The second pulp obtained from Sb was pretreated with an ultrasonic oscillator with a power density of 3W / cm 2 , the time is 3 minutes to obtain the third slurry;

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

[0089] During the flotation process, the ores from each operation are returned step by step, and finally 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% are obtained.

[0090] Example 2

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

[0092] Sa: Grind the high-sulfur bauxite with a sulfur content of 7.42% once to obtain the first pulp, and then obtain aluminum rough concentrate and sulfur concentrate through "one roughing, two cleaning and two scavenging";

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

[0094] Sc: The second pulp obtained from Sb was pretreated with an ultrasonic oscillator with a power density of 4 W / cm 2 , the time is 2 minutes to obtain the third slurry;

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

[0096] During the flotation process, the ores from each operation are returned step by step, and finally 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% are obtained.

[0097] Example 3

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

[0099] Sa: Grind the high-sulfur bauxite with a sulfur content of 8.44% once to obtain the first pulp, and then obtain aluminum rough concentrate and sulfur concentrate through "one roughing, two cleaning and three scavenging";

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

[0101] Sc: The second pulp obtained from Sb was pretreated with an ultrasonic oscillator with a power density of 4 W / cm 2 , the time is 3 minutes to obtain the third slurry;

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

[0103] During the flotation process, the ores from each operation are returned step by step, and finally 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% are obtained.

[0104] Example 4

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

[0106] Sa: Grind the high-sulfur bauxite with a sulfur content of 9.49% once to obtain the first pulp, and then obtain aluminum rough concentrate and sulfur concentrate through "one roughing, two cleaning and three scavenging";

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

[0108] Sc: The second pulp obtained from Sb was pretreated with an ultrasonic oscillator with a power density of 3W / cm 2 , the time is 7 minutes to obtain the third slurry;

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

[0110] During the flotation process, the ores from each operation are returned step by step, and finally 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% are obtained.

[0111] Example 5

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

[0113] Sa: Grind the high-sulfur bauxite with a sulfur content of 14.53% once to obtain the first pulp, and then obtain aluminum rough concentrate and sulfur concentrate through "one roughing, two cleaning and three scavenging";

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

[0115] Sc: The second pulp obtained from Sb was pretreated with an ultrasonic oscillator with a power density of 5W / cm 2 , the time is 5 minutes to obtain the third slurry;

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

[0117] During the flotation process, the ores from each operation are returned step by step, and finally 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% are obtained.

[0118] Comparative Example 1

[0119] The difference between this comparative example and Example 1 is that the Sc ultrasonic pretreatment step is not performed, and the other conditions are the same. The final aluminum concentrate yield is 80.02% and the sulfur content is 0.72%, and the sulfur concentrate yield is 19.98% and the sulfur content is 34.26%.

[0120] Comparative Example 2

[0121] The difference between this comparative example and Example 1 is that, in the Sd step, flotation is carried out in a non-transmission flotation cell after mineralization by a microbubble mineralizer, and the other conditions are the same, and finally an aluminum concentrate with a yield of 78.56% and a sulfur content of 0.68% and a sulfur concentrate with a yield of 21.44% and a sulfur content of 32.11% are obtained.

[0122] Comparative Example 3

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

[0124] Comparative Example 4

[0125] The comparative example of Chinese patent CN201910444464.4 discloses a method for refloating and desulfurizing high-sulfur bauxite. For sedimentary high-sulfur bauxite with a sulfur content of 7.42%, the grinding product fineness is -0.074mm, accounting for 76.39%. A shaking table is used to refloat and desulfurize the high-sulfur bauxite slurry. The inclination angle of the shaking table is 2.5°, the stroke is 11mm, and the stroke is 250 times / min. The refloating sulfur concentrate and the refloating aluminum concentrate are obtained; the refloating aluminum concentrate is obtained. Flotation desulfurization is directly carried out using a non-transmission flotation cell. The pH value of the slurry is adjusted to 9.0 using a pH adjuster, and then a collector, a frother, an activator and a depressant are added. The flotation desulfurization process includes one roughing selection, three cleaning selections and three scavenging selections. The flotation aluminum concentrate obtained by flotation is the final aluminum concentrate, with a yield of 79.22% and a sulfur content of 0.61%. The flotation sulfur concentrate obtained by flotation and the gravity-separated sulfur concentrate obtained by gravity-separation are combined into a comprehensive sulfur concentrate, with a yield of 20.78% and a sulfur content of 33.38%.

[0126] Comparative Example 5

[0127] The comparative example of Chinese patent CN201910444464.4 discloses a method for refloating and desulfurizing high-sulfur bauxite. For sedimentary high-sulfur bauxite with a sulfur content of 9.49%, the fineness of the grinding product is -0.074mm, accounting for 80.21%. A shaking table is used to carry out refloating and desulfurizing of the high-sulfur bauxite slurry. The inclination angle of the shaking table is 2.5°, the stroke is 11mm, and the stroke is 250 times / min. Gravity-selected sulfur concentrate and gravity-selected aluminum concentrate are obtained; the gravity-selected aluminum concentrate is mined Flotation desulfurization is directly carried out using a non-transmission flotation cell. The pH value of the slurry is adjusted to 9.0 using a pH adjuster, and then a collector, a frother, an activator and an inhibitor are added. The flotation desulfurization process includes one roughing selection, three cleaning selections and three scavenging selections. The flotation aluminum concentrate obtained by flotation is the final aluminum concentrate, with a yield of 73.76% and a sulfur content of 0.68%. The flotation sulfur concentrate obtained by flotation and the gravity-selected pyrite obtained by gravity-selection are combined into a comprehensive sulfur concentrate, with a yield of 26.24% and a sulfur content of 34.25%.

[0128] The various operating indicators and results of Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 1:

[0129] Table 1 Various operating indicators and results of Examples 1 to 5 and Comparative Examples 1 to 5

[0130]

[0131]

[0132] As can be seen from Table 1, Examples 1 to 5 adopt the technical implementation scheme of the present invention, and can obtain aluminum concentrate with a sulfur content of ≤0.5%, and a sulfur concentrate with a sulfur content of ≥36%; from the comparison of Examples 1 and 2 with Comparative Examples 1, 2, 3, and 4, and from the comparison of Example 4 with Comparative Example 5, it can be seen that under the same sulfur content conditions, the re-flotation combined desulfurization effect is worse than the direct desulfurization. However, because the sedimentary high-sulfur bauxite is generally embedded in a finer particle size, the sulfur content of the aluminum concentrate after re-selection desulfurization is still high, which is quite different from that in the examples, and the desulfurization effect on the fine particle size is not as good as the implementation scheme of this technology.

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

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

[0135] In the embodiments of the present application, the technical problem of fine-grained flotation inclusions in high-sulfur bauxite can be solved and micro-bubble flotation can be achieved. The sulfur content in the obtained aluminum concentrate can be reduced to below 0.5%, which can be used for alumina production, and 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 particle size, and has a broad application prospect.

[0136] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for desulfurization of fine-grained high-sulfur bauxite, the method comprising: Grinding the high-sulfur bauxite once to obtain a first slurry; The first slurry is subjected to a first stage of flotation desulfurization to obtain a rough aluminum concentrate and a sulfur concentrate respectively; Grinding the aluminum coarse concentrate for the second time to obtain a second slurry; The second slurry is subjected to ultrasonic pretreatment to obtain a third slurry; as well as The third slurry is subjected to microbubble flotation to obtain aluminum concentrate.

2. The method according to claim 1, characterized in that The power density of the ultrasonic pretreatment is 3W / cm 2 ~5W / cm 2 The ultrasonic pretreatment time is 2 min to 10 min.

3. The method according to claim 1, characterized in that In the second ore slurry, the number of particles with a particle size of less than 0.038 mm accounts for ≥90% of the total number of the second mineral particles.

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

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

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

7. The method according to claim 1, characterized in that The microbubble flotation uses a driveless flotation cell with a microbubble mineralizer.

8. The method according to claim 7, characterized in that The slurry delivery pressure in the microbubble mineralizer is 0.08MPa to 0.50MPa.

9. The method according to claim 8, characterized in that The microbubble mineralizer comprises: An upper sealing cavity (1), a lower sealing cavity (2), an air inlet pipe (3), a microporous tube (4), a ceramic ring (5), a sealing gasket (6), a sealing baffle (7), and an O-ring (8); wherein: The upper sealed cavity (1) and the lower sealed cavity (2) are connected by flanges and have a microporous tube (4) built in. The sealing connection parts between the built-in microporous tube (4) and the upper sealing cavity (1) and the lower sealing cavity (2) include a ceramic ring (5), a sealing gasket (6), and a sealing baffle (7); The sealing element of the flange connection is an O-ring (8).

10. The method according to claim 9, characterized in that The microporous tube (4) is a straight tube or a Venturi type tube, the opening rate of the microporous tube (4) is ≥70%, and the pore size of the microporous tube (4) is 20 μm to 150 μm.

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