A beneficiation method for lithium extraction by magnetic suspension of iron-lithium mica ore

Abstract

The application provides a beneficiation method for lithium extraction from iron lepidolite ore by magnetic suspension, which adopts a process flow of "high-gradient high-intensity magnetic separation pre-concentration-flotation recovery-flotation tailings returning to magnetic separation operation" to separate and recover the iron lepidolite, and the magnetic separation operation adopts a high-gradient magnetic separator to recover the iron lepidolite through one or more high-intensity magnetic separation operations and preliminarily separate the iron lepidolite from muscovite and other gangues; the magnetic products obtained through the magnetic separation operation are combined and subjected to flotation, and a high-efficiency iron lepidolite flotation collector LYP is used to obtain high-quality iron lepidolite concentrate; the flotation tailings are returned to the high-gradient magnetic separation operation, and finally the efficient separation of the iron lepidolite is realized. The application is a new beneficiation method for iron lepidolite ore, which is stable, efficient, has strong adaptability, good separation effect and high recovery index, and is suitable for popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and in particular relates to a mineral processing method for lithium extraction from lithium iron ore using magnetic levitation. Background Technology

[0002] Lithium is an important strategic resource, also known as an energy metal, and is a crucial raw material for batteries, light alloys, and nuclear reactors. Lithium iron ore (LEM) is one of the main lithium-extraction minerals, typically found in granite pegmatite deposits, closely associated with muscovite, feldspar, quartz, carbonates, and calcium-bearing minerals. During beneficiation, the ore easily becomes muddy, producing a large number of fine mud particles that strongly adsorb flotation reagents without selectively covering the surface of coarse minerals, thus deteriorating the slurry environment. Furthermore, the associated feldspar and quartz minerals have similar surface properties to LEM, making separation difficult. The associated carbonates and calcium-bearing minerals exhibit strong chemical adsorption with anionic components such as oleic acid in common cationic / anionic collectors, making them easily float. The associated muscovite minerals have essentially the same crystal lattice and surface properties as the target mineral, LEM, making separation by flotation difficult. The current mainstream beneficiation method for lithium mica ore is to grind the ore and remove the fine mud of -25μm or even -38μm as waste. After desliming, the coarse sand is floated. A large amount of fine lithium mica is lost in the removed fine mud. In other words, a large amount of lithium mica is lost with the fine mud. The obtained lithium mica concentrate contains a large amount of muscovite, feldspar, quartz, carbonate minerals and calcium-containing minerals, resulting in low beneficiation recovery rate and low concentrate grade.

[0003] Chinese invention patent CN 111298978 B, entitled "A Method for Flotation of Lithium Mica without Desliming," discloses a beneficiation method for lithium mica. It proposes adding sodium hexametaphosphate as a dispersant during grinding to enhance the dispersion of fine mud. Then, the roughing and two scavenging froth processes are combined and refined three times. The middlings from the refined process are combined again, and the resulting froth product is regrinded and returned to the roughing process. This method eliminates the desliming process, improving the recovery of lithium mica to some extent. However, its "strong pull and strong pressure" beneficiation method cannot effectively improve the separation of lithium mica from gangue, especially from muscovite, and is not well-suited for lithium mica ores containing large amounts of muscovite.

[0004] Chinese invention patent CN 1149180036 A, entitled "A method for directional enrichment of mica and efficient separation of lithium mica and muscovite", discloses a mica beneficiation method. It proposes to obtain mica flotation concentrate based on conventional flotation process, and then obtain higher grade mica concentrate through high-gradient magnetic separation. This method improves the separation effect of lithium iron phosphate mica from muscovite and gangue to a certain extent. However, the magnetic separation operation results in a high lithium content in the non-magnetic product and a low lithium recovery rate in the final concentrate product. In other words, the method has low resource utilization and unsatisfactory recovery effect.

[0005] Therefore, by innovating the process flow and optimizing the beneficiation reagents for lithium iron ore, and developing a beneficiation method with low lithium loss rate, good separation effect, high recovery index and strong adaptability, significant economic and social benefits can be achieved in improving the recovery effect of lithium iron ore and the utilization level of this resource. Summary of the Invention

[0006] The purpose of this invention is to provide a stable, efficient, effective separation, adaptable, and high-recovery-index maglev combined lithium extraction method for lithium iron ore, aiming to solve the problems of large lithium loss, low lithium mica recovery index, and poor separation effect between lithium mica and gangue minerals in existing lithium iron ore beneficiation technologies.

[0007] This invention is implemented as follows: a beneficiation method for combined magnetic levitation and lithium extraction from lithium iron phosphate mica ore, comprising the following steps:

[0008] (1) Grind the raw lithium mica ore into a fine powder;

[0009] (2) Add water to the finely ground slurry to adjust the slurry concentration to 8-30%;

[0010] (3) After adjusting the concentration in step (2), the slurry is subjected to strong magnetic separation to obtain magnetic products and tailings; wherein the strong magnetic separation operation conditions are: the magnetic medium is one of rod medium, mesh medium or steel wool medium, the excitation intensity is 1.0 to 1.8T, the pulsation frequency is 100 to 200 rpm, and the number of magnetic separation operation stages is 1 to 3 stages.

[0011] (4) The magnetic product obtained in step (3) is concentrated to a pulp concentration of 20-35%.

[0012] (5) The slurry concentrated in step (4) is subjected to flotation roughing of lithium mica to obtain lithium mica rough concentrate and flotation tailings I; wherein the process conditions for lithium mica roughing are: first add 100-500 g / t of dispersant sodium hexametaphosphate for 3-5 min, then add 200-1500 g / t of collector LYP for 2-3 min;

[0013] (6) The flotation tailings I obtained in step (5) are scavenged 1 to 2 times to obtain flotation tailings and scavenged ore. The scavenged ore is returned to the previous operation in sequence, and the flotation tailings are returned to the strong magnetic separation operation in step (3). The scavenging process conditions for flotation tailings I are as follows: add 0 to 250 g / t of dispersant sodium hexametaphosphate, the operation time is 3 to 5 min, and add 50 to 800 g / t of collector LYP, the action time is 2 to 3 min.

[0014] (7) The lithium mica rough concentrate obtained in step (5) is finely treated 1 to 2 times to obtain lithium mica concentrate and finely treated middlings. The finely treated middlings are returned to the previous layer of operation in sequence. The finely treated lithium mica rough concentrate process conditions are: 0 to 200 g / t of dispersant sodium hexametaphosphate and operation time of 3 to 5 min.

[0015] Preferably, in step (1), the grinding fineness is -0.074 mm and the content is 25-75%.

[0016] Preferably, in step (3), the equipment used for strong magnetic separation is a pulsed high gradient magnetic separator, and the raw material selected in the magnetic separation operation after the first stage is the non-magnetic product of the previous magnetic separation operation.

[0017] Preferably, the collector LYP is obtained by mixing cottonseed oil, safflower seed oil, cocoamine, octadecyltrimethylammonium chloride and anhydrous ethanol in a mass ratio of 3:(2-3):(2-3):2:(0-20) and stirring until homogeneous.

[0018] This invention overcomes the shortcomings of existing technologies and provides a beneficiation method for combined magnetic levitation and lithium extraction from lithium iron phosphate mica ore, which has the following technical features:

[0019] (1) Based on the fact that lithium emargite contains iron and manganese elements in its mineral lattice due to isomorphism, and has a significant difference in specific magnetic susceptibility compared with gangue minerals such as muscovite, feldspar, quartz, carbonates and calcium-containing minerals, this invention uses a high-gradient magnetic separator in combination with multiple field strengths and multiple media to efficiently recover lithium emargite. This avoids the desliming operation, recovers fine-grained lithium emargite, and improves the recovery effect of lithium emargite. It also initially realizes the separation of lithium emargite from gangue minerals such as muscovite, feldspar, quartz, carbonates and calcium-containing minerals, especially avoiding the fact that muscovite floats up with lithium emargite during the flotation process, which would affect the quality of the concentrate.

[0020] (2) This invention uses LYP as a collector to selectively adsorb lepidolite minerals and enhance the collecting ability of lepidolite. Specifically, cottonseed oil and safflower oil are rich in linoleic acid, which, as the main anionic component, has a higher degree of unsaturation and a lower complexing ability with carbonates and calcium-containing gangue. This avoids the strong adsorption of oleic acid, the main anionic component, with carbonates and calcium-containing gangue in traditional lepidolite flotation anionic-cationic combined collectors, and significantly reduces the gangue mineral content in the concentrate. In addition, cottonseed oil, safflower oil, and cocoamine undergo specific adsorption on the mineral surface. Specifically, the anionic and cationic components achieve multilayer adsorption through intermolecular association. Octadecyltrimethylammonium chloride's strong foaming properties enhance the mineralization effect of the foam in the slurry, thereby improving the collection effect of lepidolite, especially fine-grained lepidolite. This collector addresses the problem of safflower seed oil, cottonseed oil, and cocoamine easily solidifying under low winter temperatures in high-latitude regions, making it difficult to formulate in mineral processing and resulting in poor dispersion in the slurry. Adding different proportions of anhydrous ethanol as a solvent significantly lowers the collector's freezing point and improves its adaptability to low-temperature slurry environments. The collector LYP used in this invention was developed through extensive reagent adsorption and flotation experiments; its reagent composition and proportions are not publicly disclosed or easily conceived in this technical field.

[0021] (3) The present invention adopts the process flow of “high gradient strong magnetic separation pre-enrichment-flotation recovery-flotation tailings return to magnetic separation operation” to sort and recover lithium mica, which improves the recovery effect of lithium mica and the quality of concentrate. This creative idea, process flow structure and complete technology as a whole are not publicly disclosed and are not easy to think of in the field of lithium extraction from lithium mica ore. It is a new mineral processing method with stability, high efficiency, strong adaptability, good separation effect and high recovery index.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] ①This invention solves the problem of the loss of a large amount of fine-particle lithium mica in the fine mud during the conventional desliming and flotation process of lithium iron ore beneficiation, and greatly improves the lithium resource recovery effect.

[0024] ②This invention solves the problem of the inability to separate lithium iron ore and muscovite during the flotation and recovery process of lithium iron ore mica, and significantly improves the quality of lithium iron ore mica concentrate.

[0025] ③ This invention solves the problems of low collection capacity and poor selectivity of traditional reagent systems, resulting in poor separation effect from gangue minerals, as well as the problems of low freezing point and poor adaptability of traditional collectors to low-temperature slurry environments, thereby improving the low-temperature resistance of collectors and the separation efficiency of lepidolite. Attached Figure Description

[0026] Figure 1This is a flowchart of the steps in Example 4 of the present invention's beneficiation method for combined lithium extraction from lithium iron ore and mica using magnetic levitation. Figure 2 This is a flowchart of the steps in Example 5 of the beneficiation method for combined lithium extraction from lithium iron ore and mica using magnetic levitation according to the present invention. Figure 3 This is a flowchart of the steps in Example 6 of the present invention for the combined lithium extraction from iron-lithium mica ore using magnetic levitation. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] Example 1

[0029] 30g cottonseed oil, 30g safflower seed oil, 20g cocoamine, and 20g octadecyltrimethylammonium chloride were mixed and formulated as raw materials. The mixing process was carried out in a constant temperature water bath at 60℃ and normal pressure. A beaker was used as a container, and a stirrer was used for stirring (stirring time was 30 min). No other auxiliary facilities or additives were required. After uniform mixing, the collector LYP was obtained.

[0030] Example 2

[0031] 30g cottonseed oil, 25g safflower seed oil, 20g cocoamine, and 25g octadecyltrimethylammonium chloride were mixed and formulated as raw materials. The mixing process was carried out in a constant temperature water bath at 60℃ and normal pressure. A beaker was used as a container, and a stirrer was used for stirring (stirring time was 30 min). No other auxiliary facilities or additives were required. After uniform mixing, the collector LYP was obtained.

[0032] Example 3

[0033] 30g cottonseed oil, 30g safflower seed oil, 20g cocoamine, 30g octadecyltrimethylammonium chloride, and 150g anhydrous ethanol were mixed and formulated as raw materials. The mixing process was carried out in a constant temperature water bath at 60℃ and normal pressure, using a beaker as a container and a stirrer (stirring time was 30 min). No other auxiliary facilities or additives were required. After uniform mixing, the collector LYP was obtained.

[0034] Example 4

[0035] The selected ore is lepidolite ore from northern Jiangxi province. The raw ore contains 0.41% Li₂O. The main constituent minerals in the ore are lepidolite (11.36%), muscovite (7.89%), quartz (30.48%), feldspar (37.25%), kaolinite (4.07%), calcite (3.28%), carbonate minerals (1.96%), and chlorite (0.68%). Lithium is mainly found in lepidolite, and the mineral distribution is complex, exhibiting significant weathering. The lepidolite concentrate obtained using traditional desliming flotation technology contains 1.93% Li₂O with a Li₂O recovery rate of 73.60%.

[0036] The low-grade lithium iron ore was separated using the magnetic levitation combined lithium extraction method for lithium iron ore of the present invention, employing the collector LYP from Example 1. Figure 1 The selection steps are as follows:

[0037] (1) Grind the raw lithium mica ore into fine powder with a grinding fineness of -0.074 mm and a content of 45%;

[0038] (2) Add water to the finely ground slurry to adjust the slurry concentration to 16%;

[0039] (3) After adjusting the concentration in step (2), the slurry is subjected to two-stage high gradient magnetic separation to obtain two magnetic products and tailings; the operating conditions of strong magnetic separation I are: the magnetic medium is rod medium, the excitation intensity is 1.2T, and the pulsation frequency is 100rpm; the operating conditions of strong magnetic separation II are: the magnetic medium is rod medium, the excitation intensity is 1.5T, and the pulsation frequency is 150rpm.

[0040] (4) Combine the magnetic products obtained in step (3) and concentrate them. The concentration of the slurry after concentration is 30%.

[0041] (5) The slurry concentrated in step (4) is subjected to flotation roughing of lithium mica to obtain lithium mica rough concentrate and flotation tailings I; wherein the process conditions for lithium mica roughing are: first add 150g / t of dispersant sodium hexametaphosphate for 5min, then add 400g / t of collector LYP for 3min.

[0042] (6) The flotation tailings I obtained in step (5) are scavenged once to obtain flotation tailings and scavenged ore. The scavenged ore is returned to the previous operation, and the flotation tailings are returned to the magnetic separation operation in step (3). The scavenging process conditions for flotation tailings I are: 50g / t of dispersant sodium hexametaphosphate is added, the operation time is 3 min, and 100g / t of collector LYP is added, the action time is 2 min.

[0043] (7) The lithium mica rough concentrate obtained in step (5) is refined once to obtain lithium mica concentrate and refined middlings. The refined middlings are returned to the previous layer of operation in sequence. The process conditions for refining the rough concentrate are: 100g / t of dispersant sodium hexametaphosphate and operation time of 3 min.

[0044] The lithium mica concentrate obtained in this embodiment contains 2.78% Li2O and has a recovery rate of 83.27%.

[0045] Example 5

[0046] The ore selected for beneficiation was low-grade lepidolite ore from southern Jiangxi province. The raw ore contained 0.23% Li₂O. The main constituent minerals in the ore were lepidolite (17.22%), muscovite (14.17%), quartz (36.49%), feldspar (21.25%), calcite (2.17%), other carbonate minerals (5.96%), and phosphogypsum (1.61%). Lithium was mainly found in lepidolite. LA-ICP-MS analysis showed that the Li grade in the lepidolite mineral lattice decreased, equivalent to a Li₂O content of 1.31%, and the mineral embedding characteristics were complex. The lepidolite concentrate obtained by whole-sludge flotation contained 0.63% Li₂O with a Li₂O recovery rate of 88.11%.

[0047] The low-grade lithium iron ore was separated using the magnetic levitation combined lithium extraction method for lithium iron ore of the present invention, employing the collector LYP from Example 2. Figure 2 The selection steps are as follows:

[0048] (1) The raw lithium mica ore was extracted and ground to a fineness of -0.074 mm with a content of 38%;

[0049] (2) Add water to the finely ground slurry to adjust the slurry concentration to 15%;

[0050] (3) The slurry after adjusting the concentration in step (2) is subjected to three-stage high gradient magnetic separation to obtain three magnetic products and tailings; the operating conditions of strong magnetic separation I are: the magnetic medium is rod medium, the excitation intensity is 1.0T, and the pulsation frequency is 100rpm; the operating conditions of strong magnetic separation II are: the magnetic medium is rod medium, the excitation intensity is 1.4T, and the pulsation frequency is 150rpm; the operating conditions of strong magnetic separation III are: the magnetic medium is rod medium, the excitation intensity is 1.7T, and the pulsation frequency is 150rpm.

[0051] (4) Combine the magnetic products obtained in step (3) and concentrate them. The concentration of the slurry after concentration is 25%.

[0052] (5) The slurry concentrated in step (4) is subjected to flotation roughing of lithium mica to obtain lithium mica rough concentrate and flotation tailings I; wherein the lithium mica roughing process conditions are: first add 100g / t of dispersant sodium hexametaphosphate for 5min, then add 500g / t of collector LYP for 3min.

[0053] (6) The flotation tailings I obtained in step (5) are scavenged once to obtain flotation tailings and scavenged ore. The scavenged ore is returned to the previous operation, and the flotation tailings are returned to the magnetic separation operation in step (3). The scavenging process conditions for flotation tailings I are: 100g / t of dispersant sodium hexametaphosphate is added, the operation time is 3 min, and 100g / t of collector LYP is added, the action time is 2 min.

[0054] (7) The lithium iron ore concentrate obtained in step (5) is refined twice to obtain lithium iron ore concentrate and two refined middlings. These refined middlings are returned to the previous operation in sequence. The process conditions for refining the concentrate twice are as follows: in the refining operation I, 100g / t of dispersant sodium hexametaphosphate is added and the operation time is 3min; in the refining operation II, 50g / t of dispersant sodium hexametaphosphate is added and the operation time is 3min.

[0055] The lithium mica concentrate obtained in this embodiment contains 1.06% Li2O and has a recovery rate of 93.63%.

[0056] Example 6

[0057] The ore selected was a lepidolite ore from Inner Mongolia. The raw ore contained 0.37% Li₂O. The main constituent minerals in the ore were lepidolite (10.51%), muscovite (4.17%), quartz (30.24%), feldspar (46.45%), calcite (1.91%), fluorite (1.19%), and other carbonate minerals (2.24%). Lithium was mainly found in lepidolite, and the mineral distribution was complex. The lepidolite concentrate obtained using a traditional desliming flotation process contained 2.61% Li₂O with a Li₂O recovery rate of 77.24%.

[0058] The low-grade lithium iron ore was separated using the magnetic levitation combined lithium extraction method for lithium iron ore of the present invention, employing the collector LYP from Example 3. Figure 3 The selection steps are as follows:

[0059] (1) Grind the raw lithium mica ore into fine powder with a fineness of -0.074 mm and a content of 70%;

[0060] (2) Add water to the finely ground slurry to adjust the slurry concentration to 10%;

[0061] (3) The slurry after adjusting the concentration in step (2) is subjected to three-stage high gradient magnetic separation to obtain three magnetic products and tailings; the operating conditions of strong magnetic separation I are: the magnetic medium is rod medium, the excitation intensity is 1.3T, and the pulsation frequency is 100rpm; the operating conditions of strong magnetic separation II are: the magnetic medium is rod medium, the excitation intensity is 1.5T, and the pulsation frequency is 150rpm; the operating conditions of strong magnetic separation III are: the magnetic medium is mesh medium, the excitation intensity is 1.8T, and the pulsation frequency is 170rpm;

[0062] (4) Combine the magnetic products obtained in step (3) and concentrate them. The concentration of the slurry after concentration is 25%.

[0063] (5) The slurry concentrated in step (4) is subjected to flotation roughing of lithium mica to obtain lithium mica rough concentrate and flotation tailings I; wherein the lithium mica roughing process conditions are: first add 300g / t of dispersant sodium hexametaphosphate for 5min, then add 1200g / t of collector LYP for 3min.

[0064] (6) The flotation tailings I obtained in step (5) are scavenged twice to obtain flotation tailings and scavenged ore. The scavenged ore is returned to the previous operation in sequence, and the flotation tailings are returned to the magnetic separation operation in step (3). The flotation tailings scavenging process conditions are as follows: in scavenging operation I, 150g / t of dispersant sodium hexametaphosphate is added, the operation time is 3min, and 400g / t of collector LYP is added, the action time is 2min. In scavenging operation II, 300g / t of collector LYP is added, the action time is 2min.

[0065] (7) The lithium iron ore concentrate obtained in step (5) is refined twice to obtain lithium iron ore concentrate and two refined middlings. These refined middlings are returned to the previous operation in sequence. The process conditions for refining the concentrate twice are as follows: in the refining operation I, 50 g / t of dispersant sodium hexametaphosphate is added and the operation time is 3 min. In the refining operation II, 50 g / t of dispersant sodium hexametaphosphate is added and the operation time is 3 min.

[0066] The lithium mica concentrate obtained in this embodiment contains 3.11% Li2O and has a recovery rate of 84.75%.

[0067] In the above embodiments, the contents not described in detail in this specification are known prior art to those skilled in the art. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A beneficiation method for combined magnetic levitation and lithium extraction from lithium iron phosphate mica ore, characterized in that, Includes the following steps: (1) Grind the raw lithium mica ore into fine powder; (2) Add water to the finely ground slurry to adjust the slurry concentration to 8-30%; (3) After adjusting the concentration in step (2), the slurry is subjected to strong magnetic separation to obtain magnetic products and tailings; wherein the strong magnetic separation operation conditions are: the magnetic medium is one of rod medium, mesh medium or steel wool medium, the excitation intensity is 1.0 ~ 1.8T, the pulsation frequency is 100 ~ 200rpm, and the number of magnetic separation operation stages is 1 ~ 3 stages; (4) The magnetic product obtained in step (3) is concentrated to a pulp concentration of 20-35%; (5) The slurry concentrated in step (4) is subjected to flotation roughing of lithium mica to obtain lithium mica rough concentrate and flotation tailings I; wherein the process conditions for lithium mica roughing are: first add 100-500 g / t of dispersant sodium hexametaphosphate for 3-5 min, then add 200-1500 g / t of collector LYP for 2-3 min; (6) The flotation tailings I obtained in step (5) are scavenged 1 to 2 times to obtain flotation tailings and scavenged ore. The scavenged ore is returned to the previous operation in sequence, and the flotation tailings are returned to the strong magnetic separation operation in step (3). The scavenging process conditions for flotation tailings I are as follows: add 0 to 250 g / t of dispersant sodium hexametaphosphate, the operation time is 3 to 5 min, and add 50 to 800 g / t of collector LYP, the action time is 2 to 3 min. (7) The lithium mica rough concentrate obtained in step (5) is finely treated 1 to 2 times to obtain lithium mica concentrate and finely treated middlings. The finely treated middlings are returned to the previous layer of operation in sequence. The finely treated lithium mica rough concentrate process conditions are: 0 to 200 g / t of dispersant sodium hexametaphosphate and operation time of 3 to 5 min. The collector LYP is obtained by mixing cottonseed oil, safflower oil, cocoamine, octadecyltrimethylammonium chloride and anhydrous ethanol in a mass ratio of 3:(2-3):(2-3):2:(0-20) and stirring until homogeneous.

2. The beneficiation method for combined magnetic levitation and lithium extraction from lithium iron phosphate mica ore as described in claim 1, characterized in that, In step (1), the grinding fineness is -0.074 mm and the content is 25-75%.

3. The beneficiation method for combined magnetic levitation and lithium extraction from lithium iron ore mica ore as described in claim 1, characterized in that, In step (3), the equipment used for strong magnetic separation is a pulsed high gradient magnetic separator, and the raw materials selected in the magnetic separation operation after the first stage are the non-magnetic products of the previous magnetic separation operation.

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