Method for improving beneficiation indexes of spodumene ore

Abstract

The application discloses a method for improving the beneficiation index of spodumene ore. The method comprises the following steps: S1, crushing and grinding; S2, flotation, wherein the flotation process comprises pre-flotation, two-stage roughing, two-stage scavenging and three-stage cleaning in sequence; and S3, re-flotation, wherein the re-flotation process comprises two-stage roughing, two-stage scavenging and three-stage cleaning in sequence. The application discards the traditional tailing thickening and regrinding and stage grinding and beneficiation process, and innovatively adopts a cyclone to classify the tailing of the flotation, and only the coarse-grained part is regrinded and reselected. Waste rocks are pre-removed through color selection, the easy-to-float minerals are reduced to enter the subsequent flotation system, and the load of the pre-flotation operation is reduced. The application discards the traditional tailing thickening and regrinding and stage grinding and beneficiation process. The process effectively alleviates the problems of high investment and operation cost and complex process caused by the full-tailing regrinding or stage grinding and beneficiation, and avoids the deterioration of the flotation environment caused by the overgrinding of the fine-grained minerals.

Description

Technical Field

[0001] This invention relates to the field of polymetallic ore beneficiation technology, specifically to a method for improving the beneficiation index of spodumene ore. Background Technology

[0002] In recent years, the global demand for lithium resources has been continuously increasing, driven by the growing demand in the new energy vehicle and energy storage sectors, as well as the sustained growth of the 3C product market. Global lithium resources are mainly divided into brine-type lithium deposits (accounting for 67%) and hard-rock lithium deposits (accounting for 33%). Brine-type lithium deposits have long production cycles, low capacity assurance rates, and are mainly located in high-altitude areas, where transportation is inconvenient and infrastructure construction is difficult. In contrast, hard-rock lithium deposits are more widely distributed. In my country, hard-rock lithium resources are mainly distributed in four provinces and autonomous regions: Sichuan, Xinjiang, Jiangxi, and Hunan. Sichuan, in particular, is rich in lithium resources, accounting for approximately 50% of the country's hard-rock lithium deposits, and its lithium deposits are primarily spodumene deposits. Currently, spodumene mines in Xinjiang and Sichuan are under development. Industrial production practices in operational spodumene beneficiation plants have revealed the following problems in the spodumene beneficiation process: 1) In production practice, although hydrocyclones and high-frequency vibrating screens are used for two-stage classification in the grinding stage to control product particle size, there are still phenomena such as concentrate drop-off and coarse particle drop-off in spodumene separation. These are mainly concentrated in the coarse particle area of ​​+0.15mm to +0.074mm, and the spodumene loss rate in this area can account for more than 30% of the total tailings.

[0003] 2) Production practice shows that when the ball mill discharges ore, the ore is mostly biotite, amphibole, and magnetite, which are dark in color and hard in texture. Biotite and amphibole are easily floatable minerals, which have a significant impact on the concentrate index during flotation and separation, and can easily lead to unqualified concentrate grades.

[0004] 3) In spodumene separation, fine slime has a significant impact on production indicators. Especially when the spodumene ore contains layered silicate minerals such as kaolinite, montmorillonite, illite, and chlorite, a large amount of slime is generated after grinding. When this slime enters the flotation system, it easily leads to a deterioration in spodumene separation indicators.

[0005] To reduce the impact of slime, spodumene separation mostly employs single-stage or multi-stage hydrocyclone classification to remove slime-containing minerals after grinding, making the deslimed spodumene ore easier to float. To minimize the impact of easily floatable minerals such as biotite and amphibole on spodumene separation, industrial practice uses a single-stage pre-flotation to remove biotite and amphibole. The product from the flotation cell then enters the spodumene flotation system. Regarding the phenomenon of coarse spodumene particles and concentrate falling into the flotation cell, some research recommends using shallow-cell flotation machines or small flotation machines to reduce the rising height of flotation foam and allow the spodumene concentrate to float quickly. Other research suggests a process of regrinding the flotation pulp and staged grinding followed by staged separation.

[0006] Although the above-mentioned process can partially solve the problem of spodumene ore beneficiation, it is still difficult to obtain spodumene concentrate products with high beneficiation performance. The main reasons are as follows: 1) Although the hydrocyclone desliming process can remove most of the fine mud and the process flow is relatively complete, when there is a lot of fine mud, the removal of a large amount of fine mud can easily lead to an increase in the loss rate of spodumene. In addition, the hydrocyclone desliming process does not systematically consider the fine mud in the crushing dust and the fine mud generated during grinding, resulting in the selection of hydrocyclones that are too large and too numerous, the loss rate of spodumene is high, and the operation and management are relatively complex and difficult.

[0007] 2) During the pre-flotation of biotite, amphibole, and magnetite, residual spodumene collector in the grinding return water of the concentrator will enter the pre-flotation system, causing the spodumene ore to float. If the amount of biotite and amphibole is large, the flotation machine will scrape off a lot of bubbles, which can easily lead to the loss of spodumene metal.

[0008] 3) Using shallow-cell flotation machines and small-scale flotation machines can reduce the rising height of flotation foam in spodumene flotation, and using double-sided flotation scraping can accelerate the discharge speed of flotation foam. However, in the construction of large-scale mines, if a small-scale flotation machine solution is used, there will be many flotation series, high energy consumption, and greater difficulty in equipment management and reagent addition.

[0009] 4) When using a process of regrinding and re-concentrating flotation tailings or staged grinding and separation, the entire tailings need to be thickened, regrinded, and then floated again. This is equivalent to building a complete tailings thickening + grinding + flotation + reagent addition system. This results in excessive overall investment, high reagent consumption, and continued regrinding of the entire tailings can easily lead to severe mudification of fine-grained tailings, deteriorating the flotation environment.

[0010] Therefore, it is of great significance to develop a method that can improve the beneficiation index of spodumene ore. Summary of the Invention

[0011] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for improving the beneficiation indicators of spodumene ore, which can significantly improve the overall recovery rate of spodumene.

[0012] According to one aspect of the present invention, a method for improving the beneficiation index of spodumene ore is provided, comprising the following steps: S1. Crushing and grinding: The crushed lithium spodumene ore is subjected to coarse crushing, semi-autogenous grinding and screening, wherein the undersize material of the screening enters the primary cyclone classification, and the overflow of the primary cyclone classification enters the flotation process. S2. Flotation: The flotation process includes pre-flotation, two-stage roughing, two-stage scavenging, and three-stage cleaning in sequence; the large-size components of the pre-flotation enter the first-stage roughing; the small-size components of the first-stage roughing enter the second-stage and / or third-stage cleaning; the large-size components of the first-stage roughing enter the second-stage roughing; in the second-stage roughing and third-stage cleaning, the small-size components of the previous stage enter the next stage, and the small-size components of the third-stage cleaning are the concentrate; The large-particle-size components from the second-stage roughing process undergo a second-stage scavenging process; the small-particle-size components from each scavenging stage are returned to the previous stage for recycling; the large-particle-size components from the second-stage scavenging stage enter the second-stage cyclone classification. The underflow from the secondary cyclone stage enters the tertiary cyclone stage after passing through ball mill II; the overflow from the tertiary cyclone stage enters the re-flotation process. S3. Secondary flotation: Lithium concentrate is obtained after secondary flotation, wherein the secondary flotation process includes two stages of roughing, two stages of scavenging and three stages of cleaning in sequence.

[0013] The method according to embodiments of the present invention has at least the following beneficial effects: Considering the characteristics of spodumene ore, the present invention employs a modified SABC crushing process. Based on the characteristics of ores such as amphibole and magnetite—high hardness and dark color—and the clean surface of minerals after semi-autogenous grinding, the washing step is eliminated in the process, allowing stubborn rocks to directly enter the color sorting step. By pre-removing waste rock through color sorting, the amount of easily floatable minerals entering the subsequent flotation system is reduced, lowering the load on pre-flotation operations. Therefore, strong foam pulling is unnecessary; only light foam pulling is required for stable operation, thus reducing the loss rate of spodumene in the pre-flotation system by more than 80%. Addressing the problem of coarse minerals easily "falling off the spool" during flotation, the present invention abandons the traditional tailings thickening and regrinding and staged grinding processes, innovatively employing cyclone classification of flotation tailings, regrinding and re-sorting only the coarse-grained portion. This process effectively alleviates the problems of high investment and operating costs and complex processes caused by full tailings regrinding or staged grinding, while avoiding the deterioration of the flotation environment caused by over-grinding of fine-grained minerals. The main flotation process adopts a "two roughing, two scavenging, three cleaning" structure: the concentrate from roughing stage 1 directly enters cleaning stage 2 or 3, allowing easily floatable spodumene to be produced as early as possible and reducing its retention and drop-off risk in the system; the concentrate from roughing stage 2 enters cleaning stage 1, and its tailings flow by gravity to scavenging stage 1 and scavenging stage 2 in sequence; the concentrate from cleaning stage 1 enters cleaning stage 2 and cleaning stage 3 in sequence; the middlings from each scavenging and cleaning operation are returned to the previous stage for processing in sequence, forming a reasonable middlings cycle.

[0014] In summary, through color sorting and waste disposal, coarse tailings classification, regrinding and re-selection, and optimized flotation circuit design, the process of this invention achieves a spodumene loss rate of less than 8% in the pre-flotation section, increases the recovery rate of coarse spodumene in tailings to over 75%, and improves the overall spodumene recovery rate by 3%-5% compared to traditional technologies. It also has significant advantages in terms of scale, investment and operating costs.

[0015] According to some embodiments of the present invention, the color sorting is performed in two particle sizes: -25mm to +10mm and -10mm to +3mm. The color sorting uses narrow-size feed, which effectively separates gangue minerals and prevents them from entering the flotation system, thereby significantly reducing the loss of spodumene during the pre-flotation stage.

[0016] According to some embodiments of the present invention, the crushing process employs at least one of a jaw crusher, a cone crusher, or a high-pressure roller crusher.

[0017] According to some embodiments of the present invention, the method further includes a step of dust removal using a cyclone dust collector and a bag filter during the crushing process. A large amount of dust is generated at the material discharge point after crushing. A conventional combination of cyclone dust collector and bag filter is used for dust removal. The dust removed is not returned to the production system but is collected in ton bags. The collected dust is directly poured into the tailings dam, avoiding the generation of secondary fine mud in the grinding system and reducing the impact of fine mud on spodumene separation.

[0018] According to some embodiments of the present invention, the underflow of the first-stage cyclone classification is circulated after passing through ball mill I for the first-stage cyclone classification.

[0019] According to some embodiments of the present invention, the particle size limit of the first-stage cyclone classification is -0.074 mm. Preferably, -0.074 mm particles account for 55%-85% of the overflow.

[0020] According to some embodiments of the present invention, the tailings concentration after the second-stage scavenging in step S2 is 16-20%.

[0021] According to some embodiments of the present invention, the undercurrent concentration of the secondary swirl stage is 10%-15%, and the undercurrent concentration is 55%-60%.

[0022] According to some embodiments of the present invention, the concentration of the three-stage cyclone splitter is controlled between 30% and 40% before entering the re-flotation process.

[0023] According to some embodiments of the present invention, sodium carbonate and sodium hydroxide are added during the ball milling II process, wherein the amount of Na2CO3 is 450-1400 g / (t.feed) and the amount of NaOH is 60-350 g / (t.feed). The feed is calculated based on the weight of the regrinded fines.

[0024] According to some embodiments of the present invention, the method further includes a vigorous stirring treatment before re-flotation.

[0025] According to some embodiments of the present invention, the vigorous stirring time is greater than 45 minutes.

[0026] According to some embodiments of the present invention, the high-intensity stirring process is carried out by using a 4-5 stage stirring tank for high-intensity stirring.

[0027] According to some embodiments of the present invention, the reagents added during the vigorous stirring process are Na2CO3, NaOH, MgCl2 and a collector.

[0028] According to some embodiments of the present invention, the amount of Na2CO3 is 450-1400 g / (t. feed), the amount of NaOH is 60-350 g / (t. feed), the amount of MgCl2 is 200-500 g / (t. feed), and the amount of the collector is 1500-2000 g / (t. feed).

[0029] According to some embodiments of the present invention, the collector is modified oleic acid.

[0030] According to some embodiments of the present invention, the high-intensity stirring treatment is carried out by high-intensity stirring in a four-stage stirring tank, wherein Na2CO3, NaOH, MgCl2 and a collector are added sequentially in the first to fourth stage stirring tanks.

[0031] According to some embodiments of the present invention, the high-intensity stirring treatment is carried out by high-intensity stirring in a 5-stage stirring tank, wherein Na2CO3, NaOH, MgCl2 and a collector are added sequentially in the 1st to 4th stage stirring tanks, and no reagent is added in the 5th stage.

[0032] According to some embodiments of the present invention, the mass concentrations of Na2CO3, NaOH, MgCl2 and the collector are each independently selected from 8 to 12%.

[0033] According to some embodiments of the present invention, the pH of the slurry in the third-stage mixing tank during the high-intensity stirring process is 9-10.

[0034] According to some embodiments of the present invention, the total amount of sodium carbonate added during the vigorous stirring and ball milling II is 1500-2000 g / (t. feed).

[0035] According to some embodiments of the present invention, the total amount of sodium hydroxide added during the vigorous stirring and ball milling II is 200-500 g / (t. feed).

[0036] According to some embodiments of the present invention, in the re-flotation, the small-diameter components of the first-stage rougher enter the second-stage cleaner and / or the third-stage cleaner; the large-diameter components of the first-stage rougher enter the second-stage rougher; in the second-stage rougher and the third-stage cleaner, the small-diameter components of the previous stage enter the next process, and the small-diameter components of the third-stage cleaner are concentrate. The large-diameter components from the second-stage roughing process are subjected to a second-stage scavenging process; the small-diameter components from each stage of scavenging are returned to the previous process for recycling, and the large-diameter components from the second-stage scavenging process are discarded as tailings.

[0037] According to some embodiments of the present invention, the secondary flotation separation process includes the following parameters: 1) the roughing flotation time is greater than 50 min; 2) the flotation times for the first-stage to third-stage cleaning stages are each independently greater than 20 min; 3) the flotation aeration rate corresponding to the cross-sectional area of ​​the unit flotation machine is controlled between 0.8-1.4 m³. 3 / m 2 ;4) Variable frequency speed control for scraping bubbles, with the scraping speed controlled at 15-20 rpm.

[0038] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the operation process of the spodumene beneficiation method of the present invention. Detailed Implementation

[0040] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available. Unless otherwise specified, the same parameter value is the same in all embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, references to terms such as "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] In the description of this invention, the use of I, II, etc., is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0043] Unless otherwise specified, "concentration" in this invention refers to mass concentration.

[0044] In the following examples, the collector used is LF802 from Panzhihua Chirui Mining and Metallurgical Technology Development Co., Ltd.

[0045] This invention proposes a method for improving the beneficiation index of spodumene ore, such as... Figure 1 As shown. Specifically, it includes the following steps: S1. Crushing and grinding: The crushed lithium spodumene ore is subjected to coarse crushing, semi-autogenous grinding and screening, wherein the oversize material of the screening is subjected to color sorting, the target product of the color sorting is returned to the semi-autogenous grinding for recycling, and the other products are discarded as tailings. The undersize material from the screening process enters the first-stage cyclone classification, the overflow from the first-stage cyclone classification enters the flotation process, and the underflow is recycled after passing through ball mill I for the first-stage cyclone classification. S2. Flotation: The flotation process includes pre-flotation, two-stage roughing, two-stage scavenging, and three-stage cleaning in sequence; the large-size components of the pre-flotation enter the first-stage roughing; the small-size components of the first-stage roughing enter the second-stage and / or third-stage cleaning; the large-size components of the first-stage roughing enter the second-stage roughing; in the second-stage roughing and third-stage cleaning, the small-size components of the previous stage enter the next stage, and the small-size components of the third-stage cleaning are the concentrate; The large-particle-size components from the second-stage roughing process undergo a second-stage scavenging process; the small-particle-size components from each scavenging stage are returned to the previous stage for recycling; the large-particle-size components from the second-stage scavenging stage enter the second-stage cyclone classification. The underflow from the secondary cyclone stage is processed through ball mill II and then enters the tertiary cyclone stage; the underflow from the secondary cyclone stage is discarded as tailings; the overflow from the tertiary cyclone stage enters the re-flotation process; the underflow from the tertiary cyclone stage is recycled for ball mill II. S3. Secondary Flotation: The secondary flotation process includes two stages of roughing, two stages of scavenging, and three stages of cleaning in sequence; in the secondary flotation, the small-size components from the first stage roughing enter the second and / or third stages of cleaning; the large-size components from the first stage roughing enter the second stage roughing; in the second stage roughing and the third stage cleaning, the small-size components from the previous stage enter the next stage, and the small-size components from the third stage cleaning become concentrate; The large-diameter components from the second-stage roughing process are subjected to a second-stage scavenging process; the small-diameter components from each stage of scavenging are returned to the previous process for recycling, and the large-diameter components from the second-stage scavenging process are discarded as tailings.

[0046] In this invention, when jaw crusher / cone crusher / high-pressure roller crushing of spodumene ore is used, a large amount of dust will be generated at the material drop point after crushing. This invention uses a combination process of conventional cyclone dust collector + bag dust collector for dust removal. The dust after dust removal is not returned to the production system, but is recycled using ton bags. The recycled dust is directly poured into the tailings dam.

[0047] The crushing and grinding system adopts a modified SABC process flow, namely coarse crushing + semi-autogenous grinding + ball milling + screening for crushing of spodumene. The spodumene discharged from the semi-autogenous grinding has a clean surface, is mostly black ore, and has uniform particle size. A first-stage color sorting is used to discard black biotite and amphibole in the spodumene, using narrow-size rejection to separate the spodumene into -25mm to +10mm and -10mm to +3mm particles. Color sorting is then used for rejection, with a rejection rate of ≥80%. After easily floatable minerals in the spodumene no longer enter the flotation system, the pressure in the pre-flotation system is reduced, and heavy frothing is replaced with light frothing. The loss rate of spodumene in the pre-flotation system can be reduced by more than 80%.

[0048] To address the issue of coarse particles falling into the regrinding tank, this invention abandons the traditional flotation tailings thickening and regrinding, staged grinding, and staged separation processes, and instead adopts a flotation tailings hydrocyclone classification, coarse particle regrinding, and re-separation process. The process involves the spodumene ore flotation tailings first undergoing hydrocyclone classification II, with a classification particle size limit of -0.074 mm. The -0.074 mm particles flow into the hydrocyclone overflow as tailings, while the +0.074 mm particles enter the regrinding system.

[0049] The regrinding system is a closed-circuit grinding process. Specifically, the underflow of hydrocyclone stage II with a particle size of +0.074mm and the regrinding product are pumped together into hydrocyclone stage III. The underflow of hydrocyclone stage III flows into the ball mill, and the overflow of hydrocyclone stage III flows into the coarse particle reflotation system. The regrinding process requires that the overflow of hydrocyclone stage II be controlled at 70%-75% of the particle size of -0.074mm.

[0050] The flotation process adopts a two-roughing, two-scavenging, three-cleaning process. The concentrate from roughing stage 1 is fed into cleaning stage 2 or 3 to ensure that easily floatable concentrates are discharged from the flotation system as early as possible and to prevent concentrates from falling into the trough. The concentrate from roughing stage 2 is fed into cleaning stage 1, and the tailings from roughing stage 2 flow by gravity to scavenging stage 1 and scavenging stage 2 in sequence. The concentrate from roughing stage 2 is fed into cleaning stage 1, and the concentrate from cleaning stage 1 is fed into cleaning stage 2 and cleaning stage 3 in sequence. The middlings from scavenging stage 1 to scavenging stage 2 and cleaning stage 1 to cleaning stage 3 are returned to the previous stage of separation in sequence.

[0051] Before flotation, vigorous stirring is performed using 4-5 stage mixing tanks, with a stirring time exceeding 45 minutes. The reagent formulation consists of adding Na2CO3, NaOH, MgCl2, and a collector. The dosage of Na2CO3 is 1500-2000 g / (t.feed), NaOH is 200-500 g / (t.feed), MgCl2 is 200-500 g / (t.feed), and the dosage of the collector-modified oleic acid is 1500-2000 g / (t.feed).

[0052] The flotation system is a low-alkali environment with a pulp pH of 9-10. 30%-70% of the Na₂CO₃ and NaOH are added to the grinding system at a concentration of 10% (see previous instructions for dosage). The remaining Na₂CO₃ and NaOH are added to the first and second stirred tanks, respectively. MgCl₂ and the low-temperature collector (modified oleic acid), both at a concentration of 10%, are added to the third and fourth stirred tanks, respectively.

[0053] After adopting the tailings classification, regrinding, and re-selection process, the recovery rate of spodumene flotation can exceed 75%, and the overall recovery rate of spodumene separation can be improved by 3%-5%. The classification of flotation tailings is based on 100 mesh, with the portion above 100 mesh entering the regrinding and re-selection process. The fineness of the product after grinding is required to be controlled at -0.074 mm, accounting for 70%~75%.

[0054] The meaning of the plus or minus sign for particle size in this invention is explained as follows: + represents exceeding the particle size, and - represents being below the particle size.

[0055] Unless otherwise specified, the parameters in Example 2 are the same as in Example 1.

[0056] Example 1 This example provides a method for improving the beneficiation performance of spodumene ore. The specific process is as follows: Using a spodumene mine in Sichuan Province as the processing target, the raw ore has a lithium oxide grade of 1.1%. The crushing and grinding process employs the SABC process, where the crushed spodumene ore undergoes coarse crushing, semi-autogenous grinding, and screening. Dust from the crushing stage is collected in ton bags and directly discharged to the tailings dam. The oversize material obtained from screening (the stubborn rocks produced in the semi-autogenous grinding stage) is separated using a color sorter. The amount of stubborn rocks is 25% of the raw ore. Color sorting is performed in three sizes: -25mm to +10mm, -10mm to +3mm, and -3mm. The discard rate of stubborn rocks is 85%, and the Li₂O grade in the discarded rocks is only 0.1%-0.3%. The remaining color-sorted product is recycled into the semi-autogenous grinding process.

[0057] The screened material (the slurry after crushing and grinding, with a screen aperture of 1-3mm, 2mm in this example) is classified by cyclone separation (60%-65% of which are -200 mesh) and then undergoes a process of pre-flotation + flotation classification (two-stage roughing, two-stage scavenging and three-stage cleaning) + regrinding and classification + re-flotation (two-stage roughing, two-stage scavenging and three-stage cleaning).

[0058] In this process, the large-diameter fraction from the pre-flotation stage (i.e., the overflow, the portion above +20μm) enters the rougher stage 1; the small-diameter fraction from the rougher stage 1 enters the cleaner stages 2 and 3; the large-diameter fraction from the rougher stage 1 enters the rougher stage 2; in the rougher stage 2 and 3 cleaner stages, the small-diameter fraction from the previous stage enters the next stage, and the small-diameter fraction from the cleaner stage 3 becomes the concentrate; the large-diameter fraction from the rougher stage 2 undergoes a two-stage scavenging process (referred to as scavenging stage 1 and scavenging stage 2, respectively); the small-diameter fraction from each scavenging stage returns to the previous stage for recycling; the large-diameter fraction from scavenging stage 2... The tailings from the flotation (tailings from the first separation, specifically tailings 2, require further classification, regrinding, and re-selection due to coarse particles) are classified using φ250mm×16 hydrocyclones. The underflow concentration (pulp weight concentration) is 55%, the overflow concentration (pulp weight concentration) is 10%, and the final tailings concentration (pulp weight concentration) is 16%. The underflow from the second-stage hydrocyclone classification is then processed through ball mill II before entering the third-stage hydrocyclone classification. The overflow from the third-stage hydrocyclone classification enters the re-flotation process. The underflow from the third-stage hydrocyclone is returned to the regrinding ball mill, and the overflow concentration from the third-stage hydrocyclone is controlled between 30% and 40% before entering the re-flotation system. The coarse-grained grinding fineness of the tailings (cyclone overflow) is -0.074mm, accounting for 72%, and the coarse-grained tailings yield is 15%. The pH of the overflow slurry is 9-10. Sodium carbonate and sodium hydroxide are added to the regrinding system, with the addition amounts of sodium carbonate and sodium hydroxide being 1400g / t and 350g / t, respectively.

[0059] The reflotation system employs five stages of agitation before roughing. Na₂CO₃ and NaOH are added in the first and second stages at 600 g / t and 150 g / t respectively. MgCl₂ and modified oleic acid are added in the third and fourth stages at 500 g / t and 2000 g / t respectively. The fifth stage is a blank agitation stage with no added reagents. The overall agitation time is greater than 45 minutes (each stage has equal agitation time, and the agitator's installed power is 1.5 kW / m²). 3 (Volume considerations).

[0060] In the second flotation, the small-size components from the first rougher enter the second and / or third cleaning stages; the large-size components from the first rougher enter the second rougher; in the second and third rougher stages, the small-size components from the previous stage enter the next stage, and the small-size components from the third cleaning stage become the concentrate. The large-diameter components from the second-stage roughing process are subjected to a second-stage scavenging process; the small-diameter components from each stage of scavenging are returned to the previous process for recycling, and the large-diameter components from the second-stage scavenging process are discarded as tailings.

[0061] The flotation process adopts a two-stage roughing, two-stage scavenging, and three-stage cleaning process. The grade of coarse-grained tailings is 1.3%, the operating recovery rate is 78%, the concentrate grade is 5%, and the overall recovery rate is increased by 3.5% to over 80%, resulting in good mine profitability.

[0062] The total time for roughing and scavenging flotation should be greater than 50 minutes, and the time for each of the three cleaning stages (cleaning stage 1 to cleaning stage 3) should be greater than 20 minutes. The parameters for each flotation stage should be controlled as follows: the flotation aeration rate should be controlled between 0.8 and 1.4 m³ / s, based on the cross-sectional area of ​​the flotation machine. 3 / m 2 The foam scraping process requires variable frequency speed control, with the scraping speed controlled at 15-20 rpm.

[0063] The parameter settings for flotation and refloatation are the same.

[0064] Example 2 This example provides a method for improving the beneficiation performance of spodumene ore. The specific process is as follows: Using a spodumene mine in Xinjiang as the processing target, the raw ore has a lithium oxide grade of 0.98%. The crushing and grinding process employs the SABC process, where the crushed spodumene ore undergoes coarse crushing, semi-autogenous grinding, and screening. Dust from the crushing stage is collected in ton bags and directly discharged to the tailings dam. The oversize material obtained from screening (the stubborn rock produced in the semi-autogenous grinding stage) is separated using a color sorter. The amount of stubborn rock is 25% of the raw ore. Color sorting is performed in three sizes: -25mm to +10mm, -10mm to +3mm, and -3mm. The discard rate of stubborn rock is 75%, and the Li₂O grade of the waste rock is 0.15%-0.35%.

[0065] The screened material (mineral slurry after crushing and grinding, with a screen aperture of 1-3mm, 2mm in this embodiment) is classified by cyclone separation and then subjected to a process of pre-flotation + flotation classification (two-stage roughing, two-stage scavenging and three-stage cleaning) + regrinding and classification + re-flotation (two-stage roughing, two-stage scavenging and three-stage cleaning).

[0066] The pre-flotation large-diameter components (i.e., overflow, the portion above +20μm) enter the rougher stage 1; the small-diameter components of the rougher stage 1 enter the cleaner stages 2 and 3; the large-diameter components of the rougher stage 1 enter the rougher stage 2; in the rougher stage 2 and 3 cleaner stages, the small-diameter components of the previous stage enter the next process, and the small-diameter components of the cleaner stage 3 become concentrate; the large-diameter components of the rougher stage 2 undergo a two-stage scavenging process (referred to as scavenging stage 1 and scavenging stage 2 in sequence); the small-diameter components of each scavenging stage return to the previous process for recycling; the large-diameter components of scavenging stage 2 enter the two-stage hydrocyclone classification (flotation tailings are classified using φ250mm×18 hydrocyclones, with a classification underflow concentration of 60%, a classification overflow concentration of 15%, and a tailings concentration of 20% after flotation); the underflow from the two-stage hydrocyclone classification enters the three-stage hydrocyclone classification after ball milling II; the overflow from the three-stage hydrocyclone classification enters the re-flotation process.

[0067] The underflow from the secondary hydrocyclone directly enters the regrinding ball mill. The ball mill discharge enters the tertiary hydrocyclone for controlled classification. The underflow from the tertiary hydrocyclone returns to the regrinding ball mill. The overflow concentration from the tertiary hydrocyclone is controlled between 30% and 40% before entering the reflotation system. The coarse-grained tailings have a grinding fineness of -0.074mm, accounting for 75%, with a coarse-grained tailings yield of 10%. Sodium carbonate and sodium hydroxide are added to the regrinding system, with addition amounts of 1260g / t and 350g / t, respectively. Before reflotation, a five-stage stirring process is employed. Na₂CO₃ and NaOH are added in the first and second stages at dosages of 540 g / t and 150 g / t, respectively, with the pulp pH set to 10. MgCl₂ and modified oleic acid are added in the third and fourth stages at dosages of 450 g / t and 1500 g / t, respectively. The fifth stage is a blank stirring process without added reagents. The overall stirring time is greater than 45 minutes (each stage has equal stirring time, and the agitator's installed power is 1.5 kW / m²). 3 (Volume considerations).

[0068] In the second flotation, the small-size components from the first rougher enter the second and / or third cleaning stages; the large-size components from the first rougher enter the second rougher; in the second and third rougher stages, the small-size components from the previous stage enter the next stage, and the small-size components from the third cleaning stage become the concentrate. The large-diameter components from the second-stage roughing process are subjected to a second-stage scavenging process; the small-diameter components from each stage of scavenging are returned to the previous process for recycling, and the large-diameter components from the second-stage scavenging process are discarded as tailings.

[0069] The flotation process adopts a two-stage roughing, two-stage scavenging, and three-stage cleaning process. The grade of the coarse-grained tailings is 1.25%, the operating recovery rate is 75%, the concentrate grade is 5%, the overall concentrate recovery rate is increased by 3% to more than 78%, and the mine has good profitability.

[0070] The total time for roughing and scavenging flotation should be greater than 50 minutes, and the time for each of the three cleaning stages (cleaning stage 1 to cleaning stage 3) should be greater than 20 minutes. The parameters for each flotation stage should be controlled as follows: the flotation aeration rate should be controlled between 0.8 and 1.4 m³ / s, based on the cross-sectional area of ​​the flotation machine. 3 / m 2 The foam scraping process requires variable frequency speed control, with the scraping speed controlled at 15-20 rpm.

[0071] The parameter settings for flotation and refloatation are the same.

[0072] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for improving the beneficiation index of spodumene ore, characterized in that: Includes the following steps: S1. Crushing and grinding: The crushed lithium spodumene ore is subjected to coarse crushing, semi-autogenous grinding and screening, wherein the oversize material of the screening is subjected to color sorting, the target product of the color sorting is returned to the semi-autogenous grinding for recycling, and the other products are discarded as tailings. The undersize material from the screening process enters the primary cyclone classification stage, and the overflow from the primary cyclone classification stage enters the flotation process. S2. Flotation: The flotation process includes pre-flotation, two-stage roughing, two-stage scavenging, and three-stage cleaning in sequence; the large-size components of the pre-flotation enter the first-stage roughing; the small-size components of the first-stage roughing enter the second-stage and / or third-stage cleaning; the large-size components of the first-stage roughing enter the second-stage roughing; in the second-stage roughing and third-stage cleaning, the small-size components of the previous stage enter the next stage, and the small-size components of the third-stage cleaning are the concentrate; The large-particle-size components from the second-stage roughing process undergo a second-stage scavenging process; the small-particle-size components from each scavenging stage are returned to the previous stage for recycling; the large-particle-size components from the second-stage scavenging stage enter the second-stage cyclone classification. The underflow from the secondary cyclone stage enters the tertiary cyclone stage after passing through ball mill II; the overflow from the tertiary cyclone stage enters the re-flotation process. S3. Secondary flotation: Lithium concentrate is obtained after secondary flotation, wherein the secondary flotation process includes two stages of roughing, two stages of scavenging and three stages of cleaning in sequence.

2. The method for improving the beneficiation index of spodumene ore according to claim 1, characterized in that: The crushing process employs at least one of jaw crusher, cone crusher, or high-pressure roller crusher.

3. The method for improving the beneficiation index of spodumene ore according to claim 1, characterized in that: The method also includes the step of using a cyclone dust collector and a bag filter for dust removal during the crushing process.

4. The method for improving the beneficiation index of spodumene ore according to claim 1, characterized in that: The underflow from the first-stage cyclone classification is circulated after passing through ball mill I for further first-stage cyclone classification.

5. The method for improving the beneficiation index of spodumene ore according to claim 1, characterized in that: The particle size limit for the first-stage cyclone classification is -0.074 mm.

6. The method for improving the beneficiation index of spodumene ore according to claim 1, characterized in that: The ball mill II contains sodium carbonate and sodium hydroxide, wherein the amount of Na2CO3 is 450-1400 g / (t.feed) and the amount of NaOH is 60-350 g / (t.feed).

7. The method for improving the beneficiation index of spodumene ore according to claim 1 or 6, characterized in that: The method further includes a strong stirring treatment before the re-flotation separation in step S3. The strong stirring treatment is carried out by strong stirring in a 4-5 stage stirring tank. The reagents added during the strong stirring process are Na2CO3, NaOH, MgCl2 and a collector.

8. The method for improving the beneficiation index of spodumene ore according to claim 7, characterized in that: The total amount of sodium carbonate added during the high-intensity stirring and ball milling II process is 1500-2000 g / (t.feed).

9. The method for improving the beneficiation index of spodumene ore according to claim 1, characterized in that: In the re-flotation, the small-size components from the first-stage rougher enter the second-stage and / or third-stage cleaner; the large-size components from the first-stage rougher enter the second-stage rougher; in the second-stage rougher and the third-stage cleaner, the small-size components from the previous stage enter the next process, and the small-size components from the third-stage cleaner become concentrate. The large-diameter components from the second-stage roughing process are subjected to a second-stage scavenging process; the small-diameter components from each stage of scavenging are returned to the previous process for recycling, and the large-diameter components from the second-stage scavenging process are discarded as tailings.

10. The method for improving the beneficiation index of spodumene ore according to claim 9, characterized in that: The secondary flotation separation process includes the following parameters: 1) the roughing flotation time is greater than 50 min; 2) the flotation times for the first to third stage cleaning stages are each independently greater than 20 min; 3) the flotation aeration rate per unit cross-sectional area of ​​the flotation machine is controlled between 0.8 and 1.4 m³. 3 / m 2 ;4) Variable frequency speed control for scraping bubbles, with the scraping speed controlled at 15-20 rpm.

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