Low-grade titanium tailings green environmental protection re-selection process

Abstract

The application discloses a kind of low-grade titanium tailings green environmental protection reselection process, it is a kind of weathering or semi-weathered type ilmenite ore dressing tailings reselection full physical separation method, main steps are: field intensification, pre-screening, high-intensity magnetic separation, check classification, selective grinding, multi-physical field synergistic gravity separation.The application is aimed at weathering type ilmenite ore dressing tailings reselection method, can effectively recover valuable minerals in existing ilmenite ore dressing tailings.Titanium dioxide content in ilmenite tailings is 2.0-4.0%, and more than 80% of -74 μm, which is low-grade fine ilmenite, by ultrasonic dispersion intensification, precise adaptation of high gradient high-intensity magnetic separation equipment parameters, compound force field intensification of whole process physical field separation method, titanium dioxide grade greater than 44%, recovery rate greater than 40% of titanium concentrate is obtained, so that low-grade titanium tailings discarded in tailings is green environmental protection recycled, and the supply capacity of weathering, semi-weathered type titanium resources is greatly improved.

Description

Technical Field

[0001] This invention relates to a physical recovery method for the reprocessing of weathered or semi-weathered ilmenite sand tailings, specifically a green and environmentally friendly reprocessing technology for low-grade titanium tailings, belonging to the field of mineral processing. Background Technology

[0002] With rapid industrial development, my country's demand for high-quality titanium resources is increasing. Due to the superior titanium resources abroad, Chinese manufacturing enterprises have turned their attention to overseas markets. However, developing key technologies and equipment for recovering difficult-to-process titanium ore or titanium tailings domestically is crucial to resolving this contradiction. my country's titanium ore resources are widely distributed, with reserves mainly concentrated in the Panzhihua-Xichang region of Sichuan and Chengde in Hebei. Industrially, a two-stage grinding process is generally used to recover magnetite, while tailings are recovered using a combined "strong magnetic separation-flotation" process for ilmenite. However, the process limits the TiO2 grade in the iron ore tailings to no less than 8%; otherwise, only a flotation feed of less than 15% can be obtained after strong magnetic separation, resulting in high flotation costs. Despite this, current beneficiation technologies only achieve a titanium recovery rate of 40-50%, making it difficult to recover most fine-grained ilmenite, leading to the loss of titanium resources.

[0003] The titanium deposits in the Panxi and Chengde regions are rock deposits, with titanium primarily occurring as vanadium-titanium magnetite, associated with gangue minerals such as olivine and pyroxene, forming a polymetallic symbiotic deposit. Unlike the Panxi and Chengde regions, the titanium deposits in Yunnan are weathering crust type placer deposits, with more complete weathering and higher mud content. Titanium mainly exists in the form of ilmenite and titanomagnetite, associated with feldspar, pyroxene, quartz, and other minerals, with a relatively good degree of mineral liberation. Most deposits are located on the surface, with raw ore titanium dioxide grades as low as 5-8%, and mining methods primarily involve water extraction followed by sand pumping. The beneficiation process generally involves a combined method of multi-stage grinding, high-intensity magnetic separation, and spiral sluice gravity separation, yielding titanium concentrate with a titanium dioxide grade of 40%-45% and a recovery rate of less than 45%. Consequently, most of the ilmenite (TiO2: 2.0%-4.0%) is lost in the spiral sluice tailings, entering the tailings pond, resulting in a serious waste of titanium resources. Currently, there is no effective method for recovering this type of low-grade titanium tailings, mainly because ilmenite has a fine particle size, with particles of -37μm accounting for more than 40%, making it difficult for conventional beneficiation processes and equipment to achieve effective recovery. Chinese patent ZL.102861664B uses a "weak magnetic-strong magnetic" pre-disposal method for low-grade lateritic weathered titanium sand ore, and then uses a conventional "gravity separation-regrinding-gravity separation / flotation" process to obtain titanium concentrate with TiO2 content of 40-50%. However, the patent mainly targets raw materials with a feed particle size of -1 to +0.037mm, which is actually the particle size range that conventional gravity separation equipment can effectively recover. Chinese patent ZL.108993766B employs a combined strong magnetic-flotation process for weathered ilmenite with a TiO2 content of 4.0-10.0%, yielding titanium concentrate with a TiO2 content of 40-50%. However, the process utilizes large amounts of modifiers and collectors, resulting in high production costs and complex wastewater treatment. Chinese patent CN.111389583A uses a ZH combined magnetic separation device for placer-type ilmenite, followed by shaking table gravity separation of the rough concentrate, ensuring a titanium concentrate with a TiO2 content of approximately 45%. However, the overall titanium dioxide recovery rate is not ideal. Summary of the Invention

[0004] The purpose of this invention is to provide a green and environmentally friendly reprocessing technology for low-grade titanium tailings, which is used to address the loss of ilmenite in tailings after beneficiation of weathered and semi-weathered ilmenite. This process is a mineral processing technology that can efficiently recover low-grade fine-grained ilmenite. During the slurry preparation process, the strong stirring effect of ultrasound between particle interfaces is used to wash off the ore slime adsorbed or precipitated on the surface of the ilmenite. The prepared slurry is then passed through a vibrating screen to remove coarse waste rock or wood chips. The slurry under the screen directly enters the strong magnetic separation process. The strong magnetic separation concentrate enters a high-frequency vibrating fine screen. The product on the screen forms a closed-loop circulation with the rod mill. The slurry under the screen is then passed through a separation system consisting of a slime shaking table and a multi-physical field flow film beneficiator to obtain gravity-separated titanium concentrate. Finally, iron is removed by weak magnetic separation to obtain qualified titanium concentrate.

[0005] To achieve the above objectives, the present invention employs the following technical solution: a green and environmentally friendly reprocessing technology for low-grade titanium tailings, comprising the following steps:

[0006] (1) Outdoor strengthening of slurry preparation:

[0007] The tailings are placed in a stirrer equipped with an ultrasonic instrument for slurry preparation. This process ensures the slurry is uniform and dispersed, and also cleans the adsorbed and precipitated mud from the surface of the ilmenite. The resulting slurry has a concentration of 20-30%. The tailings are weathered or semi-weathered ilmenite beneficiation tailings, with a magnetite or titanomagnetite mineral content of less than 5%. The tailings contain 2-4% titanium dioxide, with a particle size of -74μm accounting for more than 80%, of which -37μm accounts for more than 40%.

[0008] (2) Pre-screening:

[0009] The prepared slurry is pre-screened by passing it through a vibrating screen. The coarse-grained waste rock or wood chips on the screen are directly discarded as tailings, while the slurry under the screen enters the strong magnetic separation process. The particle size of the undersize product is more than 90% -0.1mm.

[0010] (3) Strong magnetic pre-enrichment:

[0011] The slurry screened in step (2) is separated by a strong magnetic separator. The separation process is one roughing, one cleaning, and one scavenging. The tailings from the roughing and cleaning processes are combined and then scavenged. The scavenged concentrate is returned to the roughing process to form a closed loop. At the same time, the working parameters of the equipment are precisely adapted based on the differences in particle size and magnetic properties to obtain a strong magnetic concentrate with TiO2>18% and a recovery rate greater than 70%.

[0012] (4) Check the sieving:

[0013] The above-mentioned high-intensity magnetic separation concentrate is screened using a high-frequency vibrating fine screen to obtain oversize and undersize products; the screen aperture size of the high-frequency vibrating fine screen is 0.074mm~0.1mm;

[0014] (5) Grinding:

[0015] The oversize product obtained from the above inspection and screening is ground, and the ground product is returned to step (4) to form a closed loop, achieving selective grinding and reducing the over-grinding of ilmenite; the undersize product enters the gravity separation operation.

[0016] (6) Reselect:

[0017] The screened product enters a slime shaking table for roughing, obtaining shaking table rough concentrate, middlings I, and tailings I. Middlings I is returned to the roughing stage. The rough concentrate then enters a slime shaking table for cleaning, obtaining shaking table concentrate, middlings II, and tailings II. Middlings II is returned to the cleaning stage, and tailings II are discarded directly. Tailings I enters a multi-physics field film beneficiator for scavenging, obtaining film beneficiator rough concentrate, middlings III, and tailings III. Middlings III is returned to the film beneficiator scavenging stage, and tailings III are discarded directly. The film beneficiator rough concentrate then enters a multi-physics field film beneficiator for cleaning, obtaining film beneficiator concentrate, middlings IV, and tailings IV. Middlings IV is returned to the film beneficiator cleaning stage, and tailings IV are discarded directly.

[0018] The shaking concentrate has a TiO2 content >40.0% and an operational recovery rate >40.0%; the film concentrate has a TiO2 content >42.0% and an operational recovery rate >25%.

[0019] (7) Weak magnetic separation:

[0020] The shaker concentrate and film concentrate obtained in step (6) are combined, the slurry concentration is adjusted to 20-30%, and weak magnetic separation is performed with a magnetic field strength of 0.1-0.3T. The resulting magnetic product is magnetite, and the tailings product is the final titanium concentrate. The final titanium concentrate contains TiO2 > 44%, the magnetite contains Fe: 45-55%, and the TiO2 recovery rate in the whole process is > 40.0%.

[0021] Preferably, the stirring speed of the stirrer in step (1) is 300-600 r / min, the ultrasonic frequency is 40-60 kHz, and the power is 1500-2500 W;

[0022] Preferably, the vibrating screen in step (2) is double-layered, with the upper screen having a screen hole size of 0.3-0.5 mm and the lower screen having a screen hole size of 0.15-0.2 mm;

[0023] Preferably, the high-intensity magnetic separator mentioned in step (3) is a high-gradient magnetic separator, and the magnetic media are all rod media. The high-gradient magnetic separator used for coarsening is a non-pulsating high-gradient magnetic separator with a magnetic induction intensity of 1.2T~1.7T, a media rod diameter of 2~4mm, a slurry flow rate of 5~8cm / s, and a ring rotation speed of 2~3.5r / min. The high-gradient magnetic separator used for cleaning is a pulsating high-gradient magnetic separator with a magnetic induction intensity of 0.4T. The magnetic field strength is ~0.8T, the diameter of the medium rod is 4~6mm, the slurry flow rate is 8~12cm / s, the pulsation stroke is 25-35mm, the pulsation frequency is 200~250 times / min, and the ring rotation speed is 2~3r / min; the high gradient magnetic separator used in the scavenging is a non-pulsating high gradient magnetic separator with a magnetic field strength of 1.7~2.0T, a medium rod diameter of 1~2mm, a slurry flow rate of 2~5cm / s, and a ring rotation speed of 2~3r / min;

[0024] Preferably, the purpose of the strong magnetic roughing is to capture most of the magnetic minerals and achieve preliminary enrichment, so a pulseless high-gradient magnetic separator is used to ensure the recovery rate of magnetic minerals while taking into account the grade; the purpose of scavenging is to recover the magnetic minerals missed in the roughing and the finer-grained minerals that are difficult to capture, so a pulseless high-gradient strong magnetic separator with a finer magnetic medium is used to ensure the total recovery rate of magnetic minerals; the purpose of cleaning is to ensure the grade of magnetic minerals while taking into account the recovery rate, so a pulsed high-gradient magnetic separator is used.

[0025] Preferably, the pulseless high-gradient magnetic separator has a strong ability to collect magnetic minerals and emphasizes recovery rate, but it is prone to entraining non-magnetic gangue minerals, so it is suitable for roughing and scavenging; the pulsed high-gradient magnetic separator, by adjusting the pulse stroke and frequency, achieves the loosening of magnetic mineral agglomerations in the magnetic medium, improving grade while taking into account recovery rate.

[0026] Preferably, the grinding equipment in step (5) is a rod mill, with a grinding concentration of 55% to 70% and a filling rate of 35% to 45%;

[0027] Preferably, in step (6), the mud shaking table has a feed concentration of 15-20%, a working slope of 1-2°, and a stroke of 8-16 mm; the multi-physical field flow film concentrator has a feed concentration of 10-20%, a rotation speed of 15-25 r / min, and a vibration frequency of 15-25 Hz; the mud shaking table is preferably a fiberglass mud shaking table; the multi-physical field flow film concentrator is preferably a spherical vibrating rotary concentrator or a spherical vibrating rotary concentrator with an optimized separation surface.

[0028] The beneficial effects of the method of the present invention are:

[0029] a) Ilmenite tailings do not require deep grinding to liberate the individual particles. After field intensification and slurry preparation, they only need to be pre-screened to remove large waste rock particles before entering the beneficiation operation. This process has low energy consumption and is a green mineral processing technology.

[0030] b) Weathered and semi-weathered ilmenite tailings contain a large amount of mud, and a large amount of mud is adsorbed and precipitated on the surface of ilmenite, which seriously affects subsequent beneficiation operations. This invention utilizes ultrasonic combined with mechanical force slurry conditioning technology to clean the surface of ilmenite while weakening the interaction force between particles, thereby obtaining a loose and uniform slurry, which has a beneficial effect on beneficiation operations.

[0031] c) Based on the differences in particle size and magnetic properties, and combined with the different roles of each beneficiation operation in "quality improvement and guaranteed yield", different high-intensity magnetic separators are rationally configured, and the equipment operating parameters are precisely adapted. The key parameters such as field strength, magnetic medium size, and slurry flow rate are to be distributed in a tiered manner in the process. A high-efficiency beneficiation system with multi-dimensional parameter coordinated control is established to achieve efficient recovery and enrichment of valuable metals in titanium tailings of different particle sizes.

[0032] d) Check that the screening and rod mill form a closed-loop grinding system, which reduces the over-grinding of brittle ilmenite on the one hand, and completely liberates the target minerals to achieve selective grinding.

[0033] e) For the rough concentrate obtained by strong magnetic separation pre-enrichment, a combined separation system of shaking table and multi-physical field flow film concentrator was developed to obtain titanium concentrate with a titanium dioxide grade of more than 40%. No flotation modifiers or collectors are required in the process, and there is no complicated wastewater treatment system. It is an environmentally friendly titanium tailings beneficiation process.

[0034] f) Conventional ilmenite beneficiation typically places weak magnetic separation before strong magnetic separation. This invention, however, is tailored to the specific ore type. Based on the characteristic that magnetite in the raw ore has minimal impact on strong magnetic separation, it places weak magnetic separation at the end of the process as a deep-upgrading operation for ilmenite. This invention offers significant advantages. Specifically, placing it before strong magnetic separation requires a large-capacity magnetic separator, resulting in a large footprint, increased operational difficulty, and more complex process management, leading to higher investment and management costs. However, placing weak magnetic separation at the end of the process requires only a small magnetic separator, resulting in a smaller footprint, lower investment costs, easier operation and management, and no impact on the overall beneficiation process. This simplifies the process, saves costs, and reduces energy consumption. Attached Figure Description

[0035] Figure 1 This is a flow chart of a green and environmentally friendly reprocessing technology for low-grade titanium tailings according to the present invention. Detailed Implementation

[0036] The following embodiments further illustrate the present invention in detail, but they are not intended to limit the invention. The descriptions of the embodiments below are merely for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0037] Example 1: Reprocessing of Semi-weathered Titanium Tailings

[0038] Semi-weathered ilmenite is hosted in the weathering crust of gabbro, associated with minerals such as magnetite, hematite, limonite, plagioclase, quartz, and pyroxene. After grinding, multi-stage magnetic separation, grinding, and multi-stage gravity separation, the raw ore yields magnetite, ilmenite, and titanium tailings. The tailings contain 3.42% TiO2, 3.2% magnetite, and 85% of the material is -0.074 mm, of which 55.4% is -0.037 mm. The main gangue minerals are plagioclase, pyroxene, and quartz.

[0039] (1) Outdoor strengthening of slurry preparation:

[0040] The tailings were placed in a stirrer equipped with an ultrasonic instrument to prepare a slurry with a concentration of 25%. The stirring speed was set to 350 r / min, the ultrasonic frequency was 45 kHz, and the power was 1800 W.

[0041] (2) Pre-screening:

[0042] The prepared slurry is pre-screened by passing it through a vibrating double-layer screen. The upper screen has a screen aperture of 0.4 mm, and the lower screen has a screen aperture of 0.15 mm. The oversize product is coarse-grained waste rock or wood chips, which is directly discarded as tailings. The undersize slurry enters the high-intensity magnetic separation process, in which the undersize product has a particle size of -0.1 mm, accounting for 92%.

[0043] (3) Strong magnetic pre-enrichment:

[0044] The undersize slurry from step (2) is separated using a high-gradient magnetic separator. The separation process consists of one roughing, one cleaning, and one scavenging process. The roughing and scavenging processes are performed using a pulseless high-gradient magnetic separator, while the cleaning process is performed using a pulsed high-gradient magnetic separator. The roughing magnetic induction intensity is set to 1.6T, the media rod diameter is 3mm, the slurry flow rate is 6cm / s, and the ring rotation speed is 3r / min. The cleaning magnetic induction intensity is set to 0.5T, the media rod diameter is 4mm, the slurry flow rate is 9cm / s, the pulse stroke is 30mm, the pulse frequency is 235 times / min, and the ring rotation speed is 2.8r / min. The scavenging magnetic field intensity is set to 1.8T, the slurry flow rate is 4cm / s, the media rod diameter is 1.5mm, and the ring rotation speed is 2.5r / min. The roughing tailings and cleaning tailings are combined and then scavenged. The scavenged concentrate is returned to the roughing process to form a closed-loop cycle, resulting in a strong magnetic concentrate with TiO2 content of 20.5% and an operating recovery rate of 75%.

[0045] (4) Check the sieving:

[0046] The high-frequency fine-particle vibrating screen with a screen aperture size of 0.074 mm is used to screen the concentrate to obtain the oversize product and the undersize product.

[0047] (5) Grinding:

[0048] The oversize product obtained from the above inspection and screening is ground. The grinding equipment is a wet rod mill with a grinding concentration of 65% and a media filling rate of 40%. The ground product is returned to step (4) to form a closed loop. The undersize product enters the gravity separation operation.

[0049] (6) Reselect;

[0050] The undersize product enters a slime shaking table for roughing, with a feed concentration of 18%, a working slope of 2°, and a stroke of 10mm, yielding shaking table rough concentrate, middlings I, and tailings I. Middlings I is returned to the roughing stage. The rough concentrate then enters a slime shaking table for cleaning, yielding shaking table concentrate, middlings II, and tailings II. The shaking table concentrate contains 43% TiO2, with an operating recovery rate of 45%. Middlings II is returned to the cleaning stage, while tailings II are directly discarded. Tailings I are then processed in a multi-physics field flow film concentrator, such as a spherical vibrating concentrator. Selected, the multi-physics field film beneficiation machine is set with a feed concentration of 16%, a rotation speed of 20 r / min, and a vibration frequency of 20 Hz. It produces film beneficiation rough concentrate, middlings III, and tailings III. Middlings III are returned to the film beneficiation scavenging operation, and tailings III are directly discarded. The film beneficiation rough concentrate then enters the multi-physics field film beneficiation refining operation to obtain film beneficiation concentrate, middlings IV, and tailings IV. The film beneficiation concentrate has a TiO2 content of 44% and an operation recovery rate of 30%. Middlings IV are returned to the film beneficiation refining operation, and tailings IV are directly discarded.

[0051] (7) Weak magnetic separation operation:

[0052] The shaker concentrate and film concentrate obtained in step (6) were combined, the slurry concentration was adjusted to 25%, and weak magnetic separation was performed with a magnetic field strength of 0.2T. The resulting concentrate was magnetite, with Fe content of 52%, and the tailings product was the final titanium concentrate, with TiO2 content of 46.5%. The overall titanium dioxide recovery rate was 44.5%.

[0053] Example 2: Green and environmentally friendly reprocessing technology for weathered titanium tailings

[0054] Weathered ilmenite is formed from surface gabbro. Over a long period, physicochemical processes cause the dense rock mass to disintegrate, and some substances are leached out, while ilmenite and magnetite remain due to their stable chemical properties. After being extracted and transported by water, the raw ore reaches the concentrator. Multi-stage grinding and multi-stage magnetic-gravity separation are used to obtain titanium concentrate with a titanium dioxide grade of over 40% and a recovery rate of 40-45%. Nearly 50% or more of the valuable metals are lost in the tailings. The target minerals in the titanium tailings are ilmenite and magnetite, while gangue minerals include potassium feldspar, pyroxene, chlorite, hematite, and quartz. The TiO2 grade is 3.85%, the magnetite content is 2.9%, and 90% of the material is -0.074mm, of which 58% is -0.037mm.

[0055] (1) Outdoor strengthening of slurry preparation:

[0056] In a mixing tank equipped with an ultrasonic instrument, the slurry concentration of the tailings was adjusted to 28%, the speed of the agitator was set to 400 r / min, the ultrasonic frequency was 55 kHz, and the power was 2000 W.

[0057] (2) Pre-screening:

[0058] Pre-screening was performed using a linear vibrating screen with two layers. The upper screen had a mesh size of 0.3 mm, and the lower screen had a mesh size of 0.15 mm. The oversize product was coarse-grained waste rock, which was directly discarded as tailings. The undersize slurry entered a high-intensity magnetic separation process. 95% of the undersize product had a particle size of -0.1 mm.

[0059] (3) Strong magnetic pre-enrichment:

[0060] The undersize product (slurry) obtained from pre-screening is passed through a high-gradient magnetic separator for strong magnetic separation. Roughing and scavenging are performed using a pulseless high-gradient magnetic separator, while cleaning is performed using a pulsed high-gradient magnetic separator. The roughing magnetic induction intensity is 1.7T, the media rod diameter is 2.5mm, the slurry flow rate is 7cm / s, and the ring speed is 3.2r / min. The cleaning magnetic induction intensity is 0.6T, the media rod diameter is 5mm, the slurry flow rate is 9cm / s, the pulse stroke is 32mm, the pulse frequency is 260 times / min, and the ring speed is 3r / min. The scavenging magnetic field intensity is 1.8T, the media rod diameter is 1mm, the slurry flow rate is 3cm / s, and the ring speed is 2.0r / min. The roughing and cleaning tailings are combined and then scavenged. The scavenged concentrate is returned to the roughing process, forming a closed-loop separation system to obtain a strong magnetic concentrate with a TiO2 content of 18.6% and an operational recovery rate of 72%.

[0061] (4) Check the sieving:

[0062] The strong magnetic separation concentrate obtained in step (3) is screened using a high-frequency fine particle vibrating screen with a screen aperture size of 0.1 mm. The product on the screen enters the grinding operation, and the product under the screen enters the gravity separation operation.

[0063] (5) Grinding;

[0064] The oversize product obtained in step (4) is ground. The grinding equipment is a wet rod mill with a grinding concentration of 58% and a steel rod filling rate of 42%. The ground product is returned to step (4) to form a closed-loop circulating grinding. The undersize product enters the next stage of gravity separation feeding operation.

[0065] (6) Reselect:

[0066] The qualified product obtained in step (5) is fed into a 6-S type headstock slime shaking table for roughing. The feed concentration is 15%, the working slope is 1.5°, and the stroke is 12mm. The shaker concentrate, middlings I, and tailings I are obtained. Middlings I are returned to the roughing process. The concentrate is then fed into a slime shaking table for further cleaning to obtain shaker concentrate, middlings II, and tailings II. The shaker concentrate has a TiO2 content of 42.5% and an operating recovery rate of 43%. Middlings II are returned to the cleaning process, and tailings II are directly discarded. Tailings I are fed into a multi-physics field flow film concentrator with optimized separation surface. The spherical vibrating rotary concentrator is used for scavenging. The multi-physics field film concentrator is set with a rotation speed of 18 r / min, a vibration frequency of 16 Hz, and a feed concentration of 18%, to obtain film rough concentrate, middlings III, and tailings III. Middlings III are returned to the film concentrator for scavenging, and tailings III are directly discarded. The film rough concentrate then enters the multi-physics field film concentrator for refining, to obtain film concentrate, middlings IV, and tailings IV. The film concentrate has a TiO2 content of 42.5% and a recovery rate of 28%. Middlings IV are returned to the film concentrator for refining, and tailings IV are directly discarded.

[0067] (7) Weak magnetic separation:

[0068] The shaker concentrate and the film separator concentrate were combined, the slurry concentration was adjusted to 28%, and weak magnetic separation was performed with a magnetic field strength of 0.25T. The resulting magnetic product was magnetite with a total iron content of 49%. The tailings product was the final titanium concentrate with a TiO2 grade of 45.5%, and the titanium dioxide recovery rate in the entire process was 47.5%.

[0069] Example 3: Green and environmentally friendly mineral processing technology for weathered and semi-weathered mixed titanium tailings

[0070] The weathered and semi-weathered ilmenite sand deposits in a certain area of ​​Yunnan Province are gabbro-type deposits. After grinding, multi-stage magnetic separation, grinding, and multi-stage gravity separation, the raw ore yields magnetite, ilmenite, and tailings. The tailings have a TiO2 grade of 2.90%, a magnetite mineral content of 4.20%, and a proportion of -0.074mm particles of 88%, of which -0.037mm particles account for 45%. The main gangue minerals are plagioclase, pyroxene, quartz, and kaolinite.

[0071] (1) Outdoor strengthening of slurry preparation:

[0072] The tailings were placed in a stirrer equipped with an ultrasonic instrument for slurry preparation. By making full use of the synergistic effect of ultrasonic waves and mechanical force, a super-dispersed and uniform slurry with a concentration of 28% was prepared. The stirring speed was set to 360 r / min, the ultrasonic frequency was 42 kHz, and the power was 1600 W.

[0073] (2) Pre-screening;

[0074] The prepared slurry is pre-screened by passing it through a vibrating double-layer screen. The upper screen has a screen aperture of 0.3 mm, and the lower screen has a screen aperture of 0.15 mm. The oversize product is coarse-grained waste rock or wood chips, which is directly discarded as tailings. The undersize slurry enters the high-intensity magnetic separation process, in which the undersize product has a particle size of -0.1 mm, accounting for 91.5%.

[0075] (3) Strong magnetic pre-enrichment:

[0076] The undersize slurry from step (2) was separated using a high-gradient magnetic separator. The roughing and scavenging were performed using a pulseless high-gradient magnetic separator, while the cleaning was performed using a pulsed high-gradient magnetic separator. The roughing magnetic induction intensity was set to 1.5T, the media rod diameter to 3mm, the slurry flow rate to 6.5cm / s, and the ring rotation speed to 2.2r / min. The cleaning magnetic induction intensity was set to 0.6T, the media rod diameter to 4.5mm, the slurry flow rate to 9.5cm / s, the pulse stroke to 32mm, the pulse stroke frequency to 260 times / min, and the ring rotation speed to 2.8r / min. The scavenging magnetic field intensity was set to 1.8T, the media rod diameter to 1.5mm, the slurry flow rate to 3.5cm / s, and the ring rotation speed to 2.8r / min. The roughing tailings and cleaning tailings were combined and then scavenged. The scavenged concentrate was returned to the roughing process to form a closed loop, resulting in a high-strength magnetic concentrate with a TiO2 content of 19.7% and an operating recovery rate of 71.7%.

[0077] (4) Check the sieving;

[0078] The high-intensity magnetic separator concentrate is screened using a high-frequency fine-particle vibrating screen with a screen aperture size of 0.074 mm to obtain the oversize product and the undersize product. The oversize product is returned to the grinding operation for further grinding to liberate the monomers, while the undersize product enters the gravity separation operation.

[0079] (5) Grinding;

[0080] The oversize product obtained from the above inspection and screening is ground. The grinding equipment is a wet rod mill with a grinding concentration of 65% and a filling rate of 42%. The ground product is returned to step (4) to form a closed loop. The undersize product enters the gravity separation operation.

[0081] (6) Reselect:

[0082] The undersize product enters a new type of polyester fiberglass slime shaking table for roughing. The feed concentration is 20%, the working slope is 2°, and the stroke is 10mm, yielding shaking table rough concentrate, middlings I, and tailings I. Middlings I is returned to the roughing stage. The rough concentrate then enters a slime shaking table for cleaning, yielding shaking table concentrate, middlings II, and tailings II. The shaking table concentrate has a TiO2 content of 41.7% and an operating recovery rate of 44.5%. Middlings II is returned to the cleaning stage, and tailings II are directly discarded. Tailings I enter a multi-physics field flow film concentrator, such as a two-layer spherical vibrating rotary separator. The ore is scavenged using a multi-physics field film beneficiator with a rotation speed of 20 r / min, a vibration frequency of 22 Hz, and a feed concentration of 16%. This produces a film beneficiator rough concentrate, middlings III, and tailings III. Middlings III are returned to the film beneficiator scavenging operation, while tailings III are discarded directly. The film beneficiator rough concentrate then enters the multi-physics field film beneficiator refining operation to produce a film beneficiator concentrate, middlings IV, and tailings IV. The film beneficiator concentrate has a TiO2 content of 42.5% and a recovery rate of 26.8%. Middlings IV are returned to the film beneficiator refining operation, while tailings IV are discarded directly.

[0083] (7) Weak magnetic separation operation

[0084] The shaker concentrate and the film concentrate obtained in step (6) are combined, the slurry concentration is adjusted to 22%, and weak magnetic separation is performed. The magnetic product obtained by the magnetic field strength is 0.15T is magnetite, with Fe content of 52.5%. The tailings product is the final titanium concentrate, with TiO2 content of 44.5%. The titanium dioxide recovery rate in the whole process is 41.5%.

[0085] It should be noted that the parameters appearing in the embodiments of the present invention are only used to complement the content disclosed in the specification, so that those skilled in the art can understand and read them, and are not intended to limit the conditions under which the present invention can be implemented. Any change in the proportion or adjustment of the components, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

Claims

1. A green and environmentally friendly reprocessing technology for low-grade titanium tailings, characterized in that, Includes the following steps: 1) Enhanced field preparation of slurry: The tailings are placed in a mixer equipped with an ultrasonic instrument for slurry preparation. This process ensures the slurry is uniform and dispersed, and also cleans the adsorbed and precipitated mud from the surface of the ilmenite. The resulting slurry has a concentration of 20-30%. The tailings are weathered or semi-weathered ilmenite beneficiation tailings, with magnetite or titanomagnetite mineral content of less than 5%; the titanium dioxide content in the tailings is 2-4%, and the particle size of -74μm accounts for more than 80%, of which -37μm accounts for more than 40%. 2) Pre-screening: The prepared slurry is pre-screened by passing it through a vibrating screen. The coarse-grained waste rock or wood chips on the screen are directly discarded as tailings, while the slurry under the screen enters the strong magnetic separation operation. The particle size of the under-screen product is more than 90% ~0.1mm. The vibrating screen mentioned in step 2) is double-layered, with the upper screen having a screen aperture size of 0.3~0.5mm and the lower screen having a screen aperture size of 0.15~0.2mm; 3) Strong magnetic pre-enrichment: The slurry screened in step 2) is separated by a strong magnetic separator. The separation process is one roughing, one cleaning, and one scavenging. The tailings from the roughing and cleaning processes are combined and then scavenged. The scavenged concentrate is returned to the roughing process to form a closed loop, resulting in a strong magnetic concentrate with TiO2 > 18% and a recovery rate of over 70%. The high-intensity magnetic separator mentioned in step 3) is a high-gradient magnetic separator, and the magnetic media are all rod media. The high-gradient magnetic separator used for coarsening is a non-pulsating high-gradient magnetic separator with a magnetic induction intensity of 1.2T~1.7T, a media rod diameter of 2~4mm, a slurry flow rate of 5~8cm / s, and a ring rotation speed of 2~3.5r / min. The high-gradient magnetic separator used for cleaning is a pulsating high-gradient magnetic separator with a magnetic induction intensity of 0.4T~0. The magnetic separator used in the scavenging process has a magnetic field strength of 1.7-2.0T, a medium rod diameter of 4-6mm, a slurry flow rate of 8-12cm / s, a pulsation stroke of 25-35mm, a pulsation frequency of 200-250 times / min, and a ring rotation speed of 2-3r / min. The high gradient magnetic separator used in the scavenging process is a non-pulsating high gradient magnetic separator with a magnetic field strength of 1.7-2.0T, a medium rod diameter of 1-2mm, a slurry flow rate of 2-5cm / s, and a ring rotation speed of 2-3r / min. 4) Check the screening: The above-mentioned strong magnetic separation concentrate is screened using a high-frequency vibrating fine screen to obtain the oversize product and the undersize product; the screen aperture size of the high-frequency vibrating fine screen is 0.074mm~0.1mm; 5) Grinding: The oversize product obtained from the above screening is ground, and the ground product is returned to step 4) to form a closed loop, achieving selective grinding and reducing over-grinding of ilmenite; the undersize product enters the gravity separation operation. Step 5) The grinding equipment is a rod mill, with a grinding concentration of 55%~70% and a filling rate of 35%~45%; 6) Reselect: The screened product enters a slime shaking table for roughing to obtain shaking table rough concentrate, middlings I, and tailings I. Middlings I is returned to roughing. The rough concentrate then enters a slime shaking table for cleaning to obtain shaking table concentrate, middlings II, and tailings II. Middlings II is returned to the cleaning operation, and tailings II are directly discarded. Tailings I enter a multi-physics field film beneficiator for scavenging to obtain film rough concentrate, middlings III, and tailings III. Middlings III are returned to the film beneficiation scavenging operation, while tailings III are directly discarded. The film rough concentrate then enters a multi-physics field film beneficiation cleaning operation to obtain film concentrate, middlings IV, and tailings IV. Middlings IV are returned to the film beneficiation cleaning operation, while tailings IV are directly discarded. The shaking table concentrate has a TiO2 content >40.0% and an operational recovery rate >40.0%; the film concentrate has a TiO2 content >42.0% and an operational recovery rate >25%. 7) Weak magnetic selection: Combine the shaking concentrate and the film concentrate obtained in step 6), adjust the slurry concentration to 20-30%, and perform weak magnetic separation with a magnetic field strength of 0.1-0.3T. The resulting magnetic product is magnetite, and the tailings product is the final titanium concentrate. The final titanium concentrate contains >44% TiO2, and the magnetite contains 45-55% Fe, with a TiO2 recovery rate of >40.0% throughout the entire process.

2. The green and environmentally friendly reprocessing technology for low-grade titanium tailings according to claim 1, characterized in that, The stirring speed of the stirrer mentioned in step 1) is 300~600 r / min, the ultrasonic frequency is 40~60 kHz, and the power is 1500~2500 W.

3. The green and environmentally friendly reprocessing technology for low-grade titanium tailings according to claim 1, characterized in that, Step 6) The ore shaking table has a feed concentration of 15-20%, a working slope of 1-2°, and a stroke of 8-16mm; the multi-physical field flow film concentrator has a feed concentration of 10-20%, a rotation speed of 15-25r / min, and a vibration frequency of 15-25Hz.

4. The green and environmentally friendly reprocessing technology for low-grade titanium tailings according to claim 3, characterized in that, The ore slime shaking table is a fiberglass ore slime shaking table; the multi-physics field flow film concentrator is a spherical vibrating rotary concentrator or a spherical vibrating rotary concentrator with an optimized separation surface.

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