Lithium residue comprehensive recycling method

Abstract

The present application relates to the technical field of lithium residue treatment, and particularly relates to a comprehensive recycling method of lithium residue. The method comprises the following steps: performing pulp treatment on the lithium residue to obtain a suspension; performing grading treatment on the suspension to obtain coarse-grained lithium residue and fine-grained lithium residue; performing lithium flotation treatment on the coarse-grained lithium residue to obtain lithium concentrate and primary flotation tailings; performing grinding treatment on the primary flotation tailings to obtain grinding material; mixing the grinding material and the fine-grained lithium residue, and then performing weak magnetic separation treatment to obtain iron concentrate and tailings after weak magnetic separation; performing strong magnetic separation treatment on the tailings after weak magnetic separation to obtain weak magnetic material and tailings after strong magnetic separation; performing gravity separation treatment on the weak magnetic material to obtain tantalum-niobium concentrate and iron-rich material; and performing sulfur flotation treatment on the tailings after strong magnetic separation to obtain silicon-aluminum powder and gypsum. The present application provides a comprehensive recycling method of lithium residue, which recycles lithium concentrate and tantalum-niobium under grading treatment, and the products have high grade and recovery rate, and efficient comprehensive recycling of lithium residue is realized.

Description

Technical Field

[0001] This invention relates to the field of lithium slag treatment technology, and specifically to a method for the comprehensive recycling and utilization of lithium slag. Background Technology

[0002] With the rapid development of the lithium battery industry, the demand for lithium salts is constantly increasing. The largest sources of lithium salt resources are salt lake brine and spodumene. However, lithium extraction from brine is costly and involves complex processes, so currently, lithium salt products are mainly produced from hard lithium ore. Using spodumene to extract lithium salts produces 8-10 tons of lithium slag for every ton of lithium carbonate produced. Statistics show that in 2022, my country's basic lithium salt production was as follows: lithium carbonate 395,000 tons, lithium hydroxide 246,400 tons, and lithium chloride 22,200 tons, generating over 4 million tons of lithium slag annually. With the rapid increase in demand for lithium products, the large-scale stockpiling of lithium acid leaching residue has led to serious environmental problems. Currently, lithium acid leaching residue from spodumene is mainly used in the cement, concrete, and other building materials industries. How to efficiently and comprehensively recycle and utilize lithium acid leaching residue, turning waste into treasure, has become an urgent issue.

[0003] In the prior art, patent CN 111302708A discloses a comprehensive utilization technology and implementation method for large-volume lithium slag waste. This method uses lithium slag, admixtures, activators, water-reducing agents and chelating agents to prepare lithium slag oligomers. Although this patent solves the problem of lithium slag waste utilization rate, it is not effective in the high-value utilization method of lithium slag.

[0004] Patent CN103601230A discloses a method for the comprehensive utilization of lithium slag to produce chemical raw materials. It obtains calcium chloride, ammonium fluoride, silica, aluminum salts and ammonium sulfate through steps such as reaction of lithium slag with hydrochloric acid and filtration. This patent has high requirements for equipment and the steps are complicated and difficult to operate. Its industrial application needs further investigation.

[0005] Patent CN113511848A discloses a comprehensive utilization method for lithium slag, a by-product of lithium ore. This patent uses lithium slag and alkali to prepare water glass, and then mixes the residue with fly ash, red mud, cement and sand to prepare non-fired bricks. This patent involves strong alkali and does not comprehensively recover the valuable components in the lithium slag.

[0006] Patent CN106082739A discloses a novel lithium slag powder, its preparation method, and its application. This patent utilizes the chemical reaction between Ca(OH)2 in alkaline lithium slag and amorphous Si and Al in acidic lithium slag to produce solid hydrated calcium silicate and calcium aluminate, thereby solving the problems of prolonged initial setting time and significant reduction in 3-day strength when acidic lithium slag is used as a cement admixture. However, these patented technologies remain at the low-value stage and do not better realize the high-value utilization of spodumene-derived lithium slag.

[0007] Patent CN108273826A discloses a method for the full-phase high-value recycling of lithium slag. This patent obtains pyrophyllite raw material for glass fiber through slurry preparation, carbonate reaction, and magnetic separation. However, this method requires the crystallization and recovery of sulfate products, which has disadvantages such as high cost and makes it difficult to achieve industrial application.

[0008] Patent CN108147658A obtains pyrophyllite raw materials for glass fiber through steps such as slurry preparation, physical mineral processing and desulfurization, and magnetic separation to remove iron. Although this patent achieves high-value utilization of lithium slag, it does not comprehensively recover and utilize gypsum, tantalum, niobium, lithium and other components in the lithium slag.

[0009] Patent CN214488258U discloses a comprehensive recycling system for lithium slag, which utilizes technologies such as pre-grinding, water circulation classification, flotation desulfurization, and weak-strong magnetic separation for iron removal to comprehensively utilize lithium extraction waste from spodumene. However, this system fails to comprehensively recover lithium and iron from the lithium slag, resulting in resource waste.

[0010] Patent CN113976309A discloses a method for the comprehensive recovery of lithium, tantalum, niobium, silica-alumina micro powder, iron concentrate, and gypsum from lithium slag. This patent obtains coarse-grained niobium-tantalum rich material and coarse-grained iron concentrate through gravity separation-weak magnetic separation, and obtains high-purity gypsum concentrate and high-silicon, high-aluminum, low-iron, and low-sulfur silica-alumina micro powder through flotation and weak-magnetic-strong magnetic separation. Although this patent achieves high-value comprehensive utilization of lithium slag, the Li2O recovery rate is only about 21%, and the lithium recovery rate is low, failing to achieve efficient utilization of valuable components in lithium slag.

[0011] Therefore, it is necessary to provide a comprehensive recycling method for lithium slag, which is of great significance. Summary of the Invention

[0012] To address the problem of low comprehensive utilization efficiency of lithium slag, this invention provides a method for the comprehensive recycling of lithium slag. Through graded treatment, lithium concentrate and tantalum-niobium are recovered, and the products have high grade and recovery rate, achieving efficient comprehensive recycling of lithium slag.

[0013] This invention discloses a method for comprehensive recycling and utilization of lithium slag, comprising the following steps:

[0014] 1) Pulping treatment: The lithium slag is pulped to obtain a suspension;

[0015] 2) Grading treatment: The suspension obtained in step 1) is graded to obtain coarse-grained lithium slag and fine-grained lithium slag.

[0016] 3) Lithium flotation treatment: The coarse-grained lithium slag obtained in step 2) is subjected to lithium flotation treatment to obtain lithium concentrate and primary flotation tailings;

[0017] 4) Grinding treatment: The gravity separation tailings obtained in step 3) are ground to obtain grinding feed;

[0018] 5) Weak magnetic separation treatment: The grinding material obtained in step 5) and the fine-grained lithium slag obtained in step 2) are mixed and subjected to weak magnetic separation treatment to obtain iron concentrate and tailings after weak magnetic separation.

[0019] 6) Strong magnetic separation treatment: The tailings obtained in step 5) after weak magnetic separation are subjected to strong magnetic separation treatment to obtain weak magnetic material and tailings after strong magnetic separation.

[0020] 7) Re-separation treatment: The weakly magnetic material obtained in step 6) is subjected to re-separation treatment to obtain tantalum-niobium concentrate and iron-rich material;

[0021] 8) Sulfur flotation treatment: The tailings obtained from the strong magnetic separation in step 6) are subjected to sulfur flotation treatment to obtain silica-alumina micro powder and gypsum.

[0022] In one specific embodiment of the present invention, step 1) pulping treatment, wherein the lithium slag is the tailings obtained after lithium extraction by spodumene sulfuric acid leaching, and the moisture content of the tailings is 15-25%.

[0023] In one specific embodiment of the present invention, the slurry concentration of the suspension is 30-60%.

[0024] In one specific embodiment of the present invention, step 2) is a grading process in which the grading adopts any one or any combination of several of the following: a hydrocyclone classifier, a mechanical vibration classifier, and a spiral classifier.

[0025] In one specific embodiment of the present invention, step 3) lithium flotation treatment, wherein the pulp concentration of the lithium flotation treatment is 25-40%.

[0026] In one specific embodiment of the present invention, step 3) lithium flotation treatment includes the following steps:

[0027] 31) Lithium slag roughing: Sodium carbonate and a roughing lithium collector are added to coarse-grained lithium slag. The amount of sodium carbonate is 100-200 g / t and the amount of the roughing lithium collector is 600-1000 g / t. Roughing treatment is carried out to obtain lithium slag roughing concentrate and lithium slag roughing tailings.

[0028] 32) Primary Concentrate Refinement: Add sodium carbonate to the lithium slag rough concentrate obtained in step 31) with a dosage of 50-100 g / t, and perform primary concentrate refinement to obtain refined concentrate and primary refinement tailings.

[0029] 33) Primary scavenging of tailings: Sodium carbonate and primary scavenging lithium scavenging agent are added to the lithium slag tailings obtained in step 31). The amount of sodium carbonate is 50-100 g / t and the amount of primary scavenging lithium scavenging agent is 200-250 g / t. The tailings are then subjected to primary scavenging treatment to obtain primary scavenging concentrate and primary scavenging tailings.

[0030] 34) Middlings Concentrate Scavenging: The tailings from the primary cleaning process obtained in step 32) and the scavenged concentrate obtained in step 33) are mixed and then sodium carbonate and a lithium scavenging agent for middlings concentrate are added. The amount of sodium carbonate is 50-80 g / t and the amount of lithium scavenging agent for middlings concentrate is 100-200 g / t. Middlings concentrate scavenging is performed to obtain middlings concentrate and middlings concentrate tailings. The middlings concentrate tailings are returned to the primary scavenging process in step 33).

[0031] 35) Secondary Concentrate Refinement: Sodium carbonate is added to the refined concentrate obtained in step 32) primary refinement. The amount of sodium carbonate is 20-50 g / t. Secondary concentrate refinement is carried out to obtain lithium concentrate and secondary refinement tailings. The secondary refinement tailings are combined with the middlings scavenging tailings obtained in step 34) middlings scavenging and returned to step 32) primary refinement.

[0032] In one specific embodiment of the present invention, the roughing lithium catcher, the primary scavenging lithium catcher, and the middlings scavenging lithium catcher are composed of dodecylamine and C n H 2n-1 BrO2 is mixed in a molar ratio of 1:(10-20), where n represents a natural number from 10 to 18.

[0033] In one specific embodiment of the present invention, the C n H 2n-1 BrO2 is C n-1 H 2n-2 BrCOOH, the C n-1 H 2n- 2BrCOOH is produced by C n-1 H 2n-1 The reaction is prepared by reacting COOH with Br2 at a molar ratio of 1:1.5, wherein the reaction temperature is 70-90℃ and the reaction time is 1-3h.

[0034] In one specific embodiment of the present invention, step 4) grinding treatment, wherein the grinding adopts any one or any combination of ball mill, vertical mill, and tower mill; the slurry concentration of the grinding material is 40-60%.

[0035] In one specific embodiment of the present invention, step 5) weak magnetic separation treatment, the magnetic field strength is 0.05-0.2T, and the slurry concentration is 20-30%.

[0036] In one specific embodiment of the present invention, step 6) involves strong magnetic separation, with a magnetic field strength of 1 to 1.5 T and a slurry concentration of 10 to 20%.

[0037] In one specific embodiment of the present invention, step 7) is a gravity separation process, wherein the gravity separation is carried out using a shaking table and a spiral chute, and the pulp concentration of the gravity separation is 10-20%.

[0038] In one specific embodiment of the present invention, step 8) sulfur flotation treatment is carried out using a flotation column, and the pulp concentration of the sulfur flotation treatment is 10-20%.

[0039] In one specific embodiment of the present invention, the sulfur flotation treatment includes the following steps:

[0040] 81) Strong magnetic separation tailings roughing: Add a roughing modifier and a roughing sulfur collector to the strong magnetic separation tailings. The amount of the roughing modifier is 1500-2000 g / t and the amount of the roughing sulfur collector is 100-200 g / t. Perform strong magnetic separation tailings roughing treatment to obtain tailings roughing concentrate and tailings roughing tailings.

[0041] 82) Primary scavenging of tailings: Add a primary scavenging modifier and a primary scavenging sulfur catcher to the rough tailings obtained in step 81). The dosage of the primary scavenging modifier is 500-1000 g / t, and the dosage of the primary scavenging sulfur catcher is 50-100 g / t. Perform primary scavenging treatment on the tailings to obtain primary scavenging concentrate and primary scavenging tailings.

[0042] 83) Tailings Refinement: Add a refinement agent to the rough tailings obtained in step 81), the amount of which is 500-1000 g / t, and perform tailings refinement treatment to obtain gypsum and refined tailings. Return the refined tailings and the tailings concentrate obtained from the first scavenging of tailings in step 82) to the strong magnetic separation of tailings roughing in step 81.

[0043] 84) Secondary scavenging of tailings: Add a secondary scavenging modifier and a secondary scavenging sulfur collector to the tailings obtained in step 82) after primary scavenging. The amount of the secondary scavenging modifier is 300-500 g / t, and the amount of the secondary scavenging sulfur collector is 20-50 g / t. Perform secondary scavenging of tailings to obtain secondary scavenged tailings concentrate and silica-alumina micro powder. Return the secondary scavenged tailings concentrate to the primary scavenging of tailings in step 82).

[0044] In one specific embodiment of the present invention, the coarse selection modifier, the primary scavenging modifier, the fine selection modifier, and the secondary scavenging modifier are all selected from any one of water glass, sulfuric acid, and sodium hydroxide. The coarse selection sulfur trapping agent, the primary scavenging sulfur trapping agent, and the secondary scavenging sulfur trapping agent are all selected from any one or more of cocoamphoacetate, lauroamphoacetate, coconut oil fatty acid alanine salt, castor oil salt, oleate, and naphthenate.

[0045] In this invention, the tantalum content (calculated as Ta2O5) and niobium content (calculated as Nb2O5) in the comprehensively recycled lithium slag are both below 100 ppm; preferably, the tantalum and niobium content is 50 to 100 ppm.

[0046] This invention discloses a comprehensive lithium slag recycling method that prioritizes lithium enrichment through classification, followed by flotation separation of lithium concentrate, achieving efficient and comprehensive lithium recovery from lithium slag. The method reduces grinding volume, saves energy, and lowers processing costs through pre-classification followed by grinding. Grinding-magnetic separation-gravity separation effectively enriches tantalum and niobium minerals in the lithium slag, yielding tantalum and niobium minerals with grades higher than 100 ppm. Silica-alumina micropowder and gypsum are also separated. Lithium flotation is performed using a lithium attractant and sodium carbonate, resulting in a simple flotation process with stable chemical composition and properties. This invention's comprehensive lithium slag recycling method can efficiently recover tantalum and niobium substances from lithium slag with tantalum and niobium oxide levels below 100 ppm, with a recovery rate of >50%. Attached Figure Description

[0047] Figure 1 This is a process flow diagram of the comprehensive recycling method for lithium slag of the present invention;

[0048] Figure 2 This is a process flow diagram of the coarse-grained lithium slag lithium flotation treatment of the present invention;

[0049] Figure 3 This is a process flow diagram of the sulfur flotation treatment of tailings by strong magnetic separation according to the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0051] Based on the appendix Figure 1-3 A method for comprehensive recycling and utilization of lithium slag includes the following steps:

[0052] 1) Pulping treatment: The lithium slag is pulped to obtain a suspension;

[0053] 2) Grading treatment: The suspension obtained in step 1) is graded to obtain coarse-grained lithium slag and fine-grained lithium slag.

[0054] 3) Lithium flotation treatment: The coarse-grained lithium slag obtained in step 2) is subjected to lithium flotation treatment to obtain lithium concentrate and primary flotation tailings;

[0055] 4) Grinding treatment: The gravity separation tailings obtained in step 3) are ground to obtain grinding feed;

[0056] 5) Weak magnetic separation treatment: The grinding material obtained in step 5) and the fine-grained lithium slag obtained in step 2) are mixed and subjected to weak magnetic separation treatment to obtain iron concentrate and tailings after weak magnetic separation.

[0057] 6) Strong magnetic separation treatment: The tailings obtained in step 5) after weak magnetic separation are subjected to strong magnetic separation treatment to obtain weak magnetic material and tailings after strong magnetic separation.

[0058] 7) Re-separation treatment: The weakly magnetic material obtained in step 6) is subjected to re-separation treatment to obtain tantalum-niobium concentrate and iron-rich material;

[0059] 8) Sulfur flotation treatment: The tailings obtained from the strong magnetic separation in step 6) are subjected to sulfur flotation treatment to obtain silica-alumina micro powder and gypsum.

[0060] In some instances, in step 1), the slurry preparation process involves using tailings obtained from lithium extraction by spodumene leaching with sulfuric acid; preferably, the moisture content of the tailings is 15–25%.

[0061] In some instances, the slurry concentration of the suspension is 30–60%.

[0062] In some instances, step 2) involves grading, which employs any one or a combination of several of the following: hydrocyclone classifier, mechanical vibration classifier, and spiral classifier.

[0063] In some instances, step 3) involves lithium flotation treatment, where the pulp concentration for lithium flotation treatment is 25–40%.

[0064] In some instances, step 3) lithium flotation treatment includes the following steps:

[0065] 31) Lithium slag roughing: Sodium carbonate and a roughing lithium collector are added to coarse-grained lithium slag. The amount of sodium carbonate is 100-200 g / t and the amount of the roughing lithium collector is 600-1000 g / t. Roughing treatment is carried out to obtain lithium slag roughing concentrate and lithium slag roughing tailings.

[0066] 32) Primary Concentrate Refinement: Add sodium carbonate to the lithium slag rough concentrate obtained in step 31) with a dosage of 50-100 g / t, and perform primary concentrate refinement to obtain refined concentrate and primary refinement tailings.

[0067] 33) Primary scavenging of tailings: Sodium carbonate and primary scavenging lithium scavenging agent are added to the lithium slag tailings obtained in step 31). The amount of sodium carbonate is 50-100 g / t and the amount of primary scavenging lithium scavenging agent is 200-250 g / t. The tailings are then subjected to primary scavenging treatment to obtain primary scavenging concentrate and primary scavenging tailings.

[0068] 34) Middlings Concentrate Scavenging: The tailings from the primary cleaning process obtained in step 32) and the scavenged concentrate obtained in step 33) are mixed and then sodium carbonate and a lithium scavenging agent for middlings concentrate are added. The amount of sodium carbonate is 50-80 g / t and the amount of lithium scavenging agent for middlings concentrate is 100-200 g / t. Middlings concentrate scavenging is performed to obtain middlings concentrate and middlings concentrate tailings. The middlings concentrate tailings are returned to the primary scavenging process in step 33).

[0069] 35) Secondary Concentrate Refinement: Add sodium carbonate to the concentrate obtained from the primary refinement in step 32), with a dosage of 20-50 g / t, to perform secondary concentrate refinement to obtain lithium concentrate and secondary refinement tailings; the secondary refinement tailings are combined with the middlings scavenging tailings obtained from the middlings scavenging in step 34) and returned to the primary refinement in step 32).

[0070] In some instances, the roughing lithium catcher, the primary scavenging lithium catcher, and the middlings scavenging lithium catcher are composed of dodecylamine and C n H 2n-1 BrO2 is mixed in a molar ratio of 1:(10-20), where n represents a natural number from 10 to 18.

[0071] In some instances, C n H 2n-1 BrO2 is C n-1 H 2n-2 BrCOOH, from C n-1 H 2n-1 After melting COOH, it reacts with Br2 at 70–90℃ in a molar ratio of 1:1.5 for 2 hours to obtain the product; it is understandable that C n-1 H 2n-2 BrCOOH contains both -Br and -COOH groups; C n-1 H 2n-2The lithium collector composed of BrCOOH and dodecylamine exhibits a strong chemical bond between the polar groups in the molecule and the cations on the surface of spodumene, thus demonstrating a good lithium collection effect. At the same time, by preferentially separating the lithium, the interference of other components in the lithium slag on lithium collection is reduced. Through lithium flotation treatment, lithium resources in the lithium slag can be recovered more effectively.

[0072] In some instances, step 4) involves grinding, using any one or more of ball mills, vertical mills, and tower mills; the slurry concentration of the grinding feed is 40–60%.

[0073] In some instances, step 5) involves weak magnetic separation with a magnetic field strength of 0.05–0.2 T and a pulp concentration of 20–30%.

[0074] In some instances, weak magnetic separation processes employ weak magnetic field separators.

[0075] In some instances, step 6) involves strong magnetic separation with a magnetic field strength of 1–1.5 T and a pulp concentration of 10–20%.

[0076] In some instances, strong magnetic separation processes employ strong magnetic field separators.

[0077] In some instances, step 7) involves re-separation, which is performed using a shaking table and a spiral chute, with a pulp concentration of 10–20%.

[0078] In some instances, step 8) involves sulfur flotation, which is performed using a flotation column, with a pulp concentration of 10–20%.

[0079] In some instances, sulfur flotation treatment includes the following steps:

[0080] 81) Roughing of tailings by strong magnetic separation: Add roughing modifier and roughing sulfur catcher to the tailings by strong magnetic separation. The amount of roughing modifier is 1500-2000 g / t and the amount of roughing sulfur catcher is 100-200 g / t. Roughing treatment of tailings by strong magnetic separation is carried out to obtain roughing concentrate and roughing tailings.

[0081] 82) Primary scavenging of tailings: Add a primary scavenging modifier and a primary scavenging sulfur catcher to the rough tailings obtained in step 81). The dosage of the primary scavenging modifier is 500-1000 g / t, and the dosage of the primary scavenging sulfur catcher is 50-100 g / t. Perform primary scavenging treatment on the tailings to obtain primary scavenging concentrate and primary scavenging tailings.

[0082] 83) Concentrate Refinement: Add a refinement modifier to the tailings rough concentrate obtained in step 81), the amount of which is 500-1000 g / t, and perform tailings refinement treatment to obtain gypsum and refined tailings. Return the refined tailings and the tailings primary scavenging concentrate obtained in step 82) to step 81) strong magnetic separation tailings roughing.

[0083] 84) Secondary scavenging of tailings: Add secondary scavenging modifier and secondary scavenging sulfur catcher to the tailings obtained from the primary scavenging of tailings in step 82). The amount of secondary scavenging modifier is 300-500 g / t, and the amount of secondary scavenging sulfur catcher is 20-50 g / t. Perform secondary scavenging of tailings to obtain secondary scavenged tailings concentrate and silica-alumina powder. Return the secondary scavenged tailings concentrate to the primary scavenging of tailings in step 82).

[0084] In some examples, the roughing agent, primary scavenging agent, cleaning agent, and secondary scavenging agent are all selected from any one of water glass, sulfuric acid, and sodium hydroxide. The roughing sulfur trapping agent, primary scavenging sulfur trapping agent, and secondary scavenging sulfur trapping agent are all selected from any one or more of cocoamphoacetic acid and its salts, lauroamphoacetic acid and its salts, coconut oil fatty acid alanine and its salts, ricinoleic acid and its salts, oleic acid and its salts, and naphthenic acid and its salts. Cocoaamphoacetic acid and its salts are preferably sodium cocoamphoacetate; lauroamphoacetic acid and its salts are preferably sodium lauroamphoacetate; coconut oil fatty acid alanine and its salts are preferably sodium coconut oil fatty acid alanine; ricinoleic acid and its salts are preferably sodium ricinoleate; oleic acid and its salts are preferably sodium oleate; and naphthenic acid and its salts are preferably sodium naphthenate.

[0085] Example 1

[0086] This embodiment focuses on the treatment of lithium extraction slag from a lithium company in Sichuan. The main component analysis results of the lithium slag are shown in Table 1.

[0087] Table 1

[0088]

[0089]

[0090] To comprehensively recycle and utilize this lithium slag, a method for comprehensive recycling and utilization of lithium slag is provided, the specific steps of which are as follows:

[0091] 1. Add water to lithium slag and stir to make a slurry with a slurry concentration of 50%.

[0092] 2. The suspension is classified using a hydrocyclone to obtain fine-grained lithium slag and coarse-grained lithium slag; wherein the fine-grained lithium slag contains more than 90% -325 mesh.

[0093] 3. Lithium flotation is performed on coarse-grained lithium slag, with a pulp concentration of 35%. The lithium flotation process is as follows: lithium slag roughing - primary concentrate cleaning - primary tailings scavenging - middlings cleaning - secondary concentrate cleaning. Specifically, the Na2CO3 dosage in the lithium slag roughing process is 200 g / t, and the lithium collector dosage is 1000 g / t; the Na2CO3 dosage in the primary concentrate cleaning is 100 g / t; the Na2CO3 dosage in the secondary concentrate cleaning is 50 g / t; the Na2CO3 dosage in the primary tailings scavenging is 100 g / t, and the lithium collector dosage is 200 g / t; the Na2CO3 dosage in the middlings cleaning is 80 g / t, and the lithium collector dosage is 200 g / t. The lithium collector consists of dodecylamine and C... 11 H 22 BrCOOH is mixed in a molar ratio of 1:15; the lithium concentrate obtained from the secondary beneficiation of the concentrate is dehydrated and dried to obtain the finished lithium concentrate product.

[0094] 4. After concentrating the flotation underflow slurry, it is added to a ball mill for grinding to obtain grinding feed; wherein, the grinding media is steel balls, the grinding concentration is 55%, and the grinding fineness is -325 mesh with a content greater than 90%.

[0095] 5. The grinding material is subjected to weak magnetic separation. The slurry concentration of the weak magnetic separation is 30% and the magnetic field strength is 0.1T, to obtain weak magnetic separation tailings and iron concentrate. The weak magnetic separation tailings are then subjected to strong magnetic separation. The slurry concentration of the strong magnetic separation is 25% and the magnetic field strength is 1.2T.

[0096] 6. The weakly magnetic material obtained from the strong magnetic separation operation is subjected to gravity separation using a spiral sluice and a shaking table. The slurry concentration of the gravity separation operation is 20%. The tantalum-niobium rough concentrate is obtained by gravity separation using a spiral sluice, and then the tantalum-niobium rough concentrate is further refined using a shaking table to obtain tantalum-niobium concentrate. The tailings from the gravity separation process are combined together to obtain iron-rich material.

[0097] 7. Sulfur flotation is performed on the tailings from the high-intensity magnetic separation using flotation columns, with a sulfur flotation pulp concentration of 15%. The sulfur flotation process is as follows: high-intensity magnetic separation tailings roughing – primary tailings scavenging – tailings cleaning – secondary tailings scavenging. Specifically, the water glass dosage for the high-intensity magnetic separation tailings roughing is 1500 g / t, and the sodium cocoamphoacetate dosage is 200 g / t; the water glass dosage for the tailings cleaning is 500 g / t; the water glass dosage for the primary tailings scavenging is 1000 g / t, and the sodium cocoamphoacetate dosage is 80 g / t; the water glass dosage for the secondary tailings scavenging is 500 g / t, and the sodium cocoamphoacetate dosage is 30 g / t. The products obtained from the sulfur flotation are filtered and dried to obtain gypsum and silica-alumina micro powder.

[0098] Example 2

[0099] This embodiment addresses the same lithium slag as in Example 1, providing a method for the comprehensive recycling and utilization of lithium slag. The specific steps are as follows:

[0100] 1. Add water to lithium slag and stir to make a slurry with a slurry concentration of 40%.

[0101] 2. The suspension is classified using a mechanical vibrating screen with a mesh size of 200 mesh to obtain fine-grained lithium slag and coarse-grained lithium slag.

[0102] 3. Lithium flotation is performed on coarse-grained lithium slag, with a pulp concentration of 30%. The lithium flotation process is as follows: lithium slag roughing - primary concentrate cleaning - primary tailings scavenging - middlings cleaning - secondary concentrate cleaning. Specifically, the Na2CO3 dosage in the lithium slag roughing process is 100 g / t, and the lithium collector dosage is 600 g / t; the Na2CO3 dosage in the primary concentrate cleaning is 80 g / t; the Na2CO3 dosage in the secondary concentrate cleaning is 30 g / t; the Na2CO3 dosage in the primary tailings scavenging is 50 g / t, and the lithium collector dosage is 200 g / t; the Na2CO3 dosage in the middlings cleaning is 50 g / t, and the lithium collector dosage is 100 g / t. The lithium collector consists of dodecylamine and C... 11 H 22 BrCOOH is mixed at a molar ratio of 1:15. The lithium concentrate obtained from the secondary beneficiation of the concentrate is then dehydrated and dried to obtain the finished lithium concentrate product.

[0103] 4. After concentrating the lithium flotation underflow slurry, it is added to a vertical mill for grinding to obtain grinding material; wherein, the grinding media for grinding is steel forging, the grinding concentration is 55%, and the grinding fineness is -325 mesh with a content greater than 90%.

[0104] 5. The grinding material is subjected to weak magnetic separation. The slurry concentration of the weak magnetic separation is 25% and the magnetic field strength is 0.15T. The weak magnetic separation tailings and iron concentrate are obtained. The weak magnetic separation tailings are then subjected to strong magnetic separation. The slurry concentration of the strong magnetic separation is 20% and the magnetic field strength is 1.5T.

[0105] 6. The weakly magnetic material obtained from the strong magnetic separation operation is subjected to gravity separation using a spiral sluice and a shaking table. The slurry concentration of the gravity separation operation is 15%. The tantalum-niobium rough concentrate is obtained by gravity separation using a spiral sluice, and then the tantalum-niobium rough concentrate is further refined using a shaking table to obtain tantalum-niobium concentrate. The tailings from the gravity separation operation are combined together as iron-rich material.

[0106] 7. Sulfur flotation is performed on the tailings from the high-intensity magnetic separation using flotation columns, with a sulfur flotation pulp concentration of 15%. The sulfur flotation process is as follows: high-intensity magnetic separation tailings roughing – primary tailings scavenging – tailings cleaning – secondary tailings scavenging. Specifically, the water glass dosage for the high-intensity magnetic separation tailings roughing is 2000 g / t, and the coconut oil fatty acid sodium alanine dosage is 200 g / t; the water glass dosage for the tailings cleaning is 1000 g / t; the water glass dosage for the primary tailings scavenging is 1000 g / t, and the coconut oil fatty acid sodium alanine dosage is 100 g / t; the water glass dosage for the secondary tailings scavenging is 500 g / t, and the coconut oil fatty acid sodium alanine dosage is 50 g / t. The obtained products are filtered and dried to obtain gypsum and silica-alumina micro powder.

[0107] Example 3

[0108] This embodiment addresses the same lithium slag as in Example 1, providing a method for the comprehensive recycling and utilization of lithium slag. The specific steps are as follows:

[0109] 1. Add water to lithium slag and stir to make a slurry with a slurry concentration of 50%.

[0110] 2. The suspension is classified using a spiral classifier to obtain fine-grained lithium slag and coarse-grained lithium slag; wherein the content of -325 mesh in the fine-grained lithium slag is greater than 90%.

[0111] 3. Lithium flotation is performed on coarse-grained lithium slag, with a pulp concentration of 35%. The lithium flotation process is as follows: lithium slag roughing - primary concentrate cleaning - primary tailings scavenging - middlings cleaning - secondary concentrate cleaning. Specifically, the Na2CO3 dosage in the lithium slag roughing process is 150 g / t, and the lithium collector dosage is 800 g / t; the Na2CO3 dosage in the primary concentrate cleaning is 70 g / t; the Na2CO3 dosage in the secondary concentrate cleaning is 20 g / t; the Na2CO3 dosage in the primary tailings scavenging is 80 g / t, and the lithium collector dosage is 200 g / t; the Na2CO3 dosage in the middlings cleaning is 60 g / t, and the lithium collector dosage is 150 g / t. The lithium collector consists of dodecylamine and C... 11 H 22 BrCOOH is mixed at a molar ratio of 1:15. The lithium concentrate obtained from the secondary beneficiation of the concentrate is then dehydrated and dried to obtain the finished lithium concentrate product.

[0112] 4. After concentrating the flotation underflow slurry, it is fed into a tower mill for grinding to obtain grinding feed; wherein, the grinding media is steel balls, the grinding concentration is 50%, and the grinding fineness is -325 mesh with a content greater than 95%.

[0113] 5. The grinding material is subjected to weak magnetic separation. The slurry concentration of the weak magnetic separation is 30% and the magnetic field strength is 0.2T, to obtain weak magnetic separation tailings and iron concentrate. The weak magnetic separation tailings are then subjected to strong magnetic separation. The slurry concentration of the strong magnetic separation is 25% and the magnetic field strength is 1.3T.

[0114] 6. The weakly magnetic material obtained from the strong magnetic separation operation is subjected to gravity separation using a spiral sluice and a shaking table. The slurry concentration for the gravity separation operation is 20%. The tantalum-niobium rough concentrate is obtained by gravity separation using a spiral sluice, and then the tantalum-niobium rough concentrate is further refined using a shaking table to obtain tantalum-niobium concentrate. The tailings from the gravity separation operation are combined together as iron-rich material.

[0115] 7. Sulfur flotation is performed on the tailings from the high-intensity magnetic separation using flotation columns, with a sulfur flotation pulp concentration of 10%. The sulfur flotation process is as follows: high-intensity magnetic separation tailings roughing – primary tailings scavenging – tailings cleaning – secondary tailings scavenging. Specifically, the dosage of sodium hydroxide in the high-intensity magnetic separation tailings roughing is 1800 g / t, and the dosage of sodium ricinoleate is 150 g / t; the dosage of sodium hydroxide in the tailings cleaning is 500 g / t; the dosage of sodium hydroxide in the primary tailings scavenging is 800 g / t, and the dosage of sodium ricinoleate is 70 g / t; the dosage of sodium hydroxide in the secondary tailings scavenging is 400 g / t, and the dosage of sodium ricinoleate is 30 g / t. The obtained products are filtered and dried to obtain gypsum and silica-alumina micropowder.

[0116] Comparative Example 1

[0117] This comparative example treats the same lithium slag as in Example 1, and provides a method for the comprehensive recycling and utilization of lithium slag. The specific steps are as follows:

[0118] 1. Add water to lithium slag and stir to make a slurry with a slurry concentration of 50%.

[0119] 2. Lithium flotation is performed on the suspension, with a pulp concentration of 35%. The lithium flotation process is as follows: lithium slag roughing - primary concentrate cleaning - primary tailings scavenging - middlings cleaning - secondary concentrate cleaning. Specifically, the Na2CO3 dosage in the lithium slag roughing process is 150 g / t, and the lithium collector dosage is 800 g / t; the Na2CO3 dosage in the primary concentrate cleaning is 70 g / t; the Na2CO3 dosage in the secondary concentrate cleaning is 20 g / t; the Na2CO3 dosage in the primary tailings scavenging is 80 g / t, and the lithium collector dosage is 200 g / t; the Na2CO3 dosage in the middlings cleaning is 60 g / t, and the lithium collector dosage is 150 g / t. The lithium collector consists of dodecylamine and C... 11 H 22 BrCOOH is mixed with molar ratio 1:15.

[0120] The lithium concentrate obtained from the secondary beneficiation of the concentrate is dehydrated and dried to obtain the finished lithium concentrate product.

[0121] 3. After concentrating the flotation underflow slurry, it is fed into a tower mill for grinding to obtain grinding feed; wherein, the grinding media is steel balls, the grinding concentration is 50%, and the grinding fineness is -325 mesh with a content greater than 95%.

[0122] 4. The grinding material is subjected to weak magnetic separation. The slurry concentration for weak magnetic separation is 30% and the magnetic field strength is 0.2T. The tailings obtained from weak magnetic separation are then subjected to strong magnetic separation. The slurry concentration for strong magnetic separation is 25% and the magnetic field strength is 1.3T.

[0123] 5. The weakly magnetic material obtained from the strong magnetic separation operation is subjected to gravity separation using a spiral sluice and a shaking table. The slurry concentration of the gravity separation operation is 20%. The tantalum-niobium rough concentrate is obtained by gravity separation using a spiral sluice, and then the tantalum-niobium rough concentrate is further refined using a shaking table to obtain tantalum-niobium concentrate. The tailings from the gravity separation operation are combined together as iron-rich material.

[0124] 6. Sulfur flotation was performed on the tailings from the high-intensity magnetic separation using flotation columns, with a sulfur flotation pulp concentration of 0%. The sulfur flotation process consisted of high-intensity magnetic separation tailings roughing, primary tailings scavenging, tailings cleaning, and secondary tailings scavenging. Specifically, the water glass dosage for the high-intensity magnetic separation tailings roughing was 1800 g / t, and the sodium cocoamphoacetate dosage was 150 g / t; the water glass dosage for the tailings cleaning was 700 g / t; the water glass dosage for the primary tailings scavenging was 800 g / t, and the sodium cocoamphoacetate dosage was 70 g / t; and the water glass dosage for the secondary tailings scavenging was 400 g / t, and the sodium cocoamphoacetate dosage was 30 g / t. The obtained products were filtered and dried to obtain gypsum and silica-alumina micro powder.

[0125] Compositional Analysis: The lithium concentrate, tantalum-niobium concentrate, iron-rich material, gypsum, and silica-alumina micro powder obtained in Examples 1-3 and Comparative Example 1 were subjected to compositional analysis. The lithium concentrate was analyzed according to GB / T 17413.1-2010 Chemical Analysis Methods for Lithium, Rubidium, and Cesium Ores. The tantalum and niobium in the tantalum-niobium concentrate were analyzed according to GB / T 15076.1-2017 Chemical Analysis Methods for Tantalum and Niobium Part 1: Determination of Tantalum Content in Niobium by Inductively Coupled Plasma Atomic Emission Spectrometry and GB / T 15076.2-2019 Chemical Analysis Methods for Tantalum and Niobium Part 2: Determination of Niobium Content in Tantalum by Inductively Coupled Plasma Atomic Emission Spectrometry and Chromatographic Gravimetric Method, respectively. The purity of the gypsum was determined according to GB / T The purity of the silica-alumina micropowder was determined according to GB / T14506.31-2019 Chemical Analysis Methods for Silicate Rocks Part 31: Determination of 12 Components Including Silica by Lithium Metaborate Fusion-Inductively Coupled Plasma Atomic Emission Spectrometry.

[0126] The yield, Li2O grade, and Li2O recovery rate of lithium concentrate in Examples 1-3 and Comparative Example 1 are statistically analyzed in Table 2.

[0127] Table 2

[0128] Yield (%) <![CDATA[Li2O grade (%)]]> <![CDATA[Recovery rate of Li2O (%)]]> Example 1 4.27 5.83 46.97 Example 2 3.85 5.96 43.29 Example 3 4.31 5.61 45.62 Comparative Example 1 6.12 2.63 30.37

[0129] The yield, grade, and recovery results of tantalum-niobium concentrates in Examples 1-3 and Comparative Example 1 are statistically shown in Table 3.

[0130] Table 3

[0131]

[0132]

[0133] The yield, grade, and recovery rate of the gypsum products in Examples 1-3 and Comparative Example 1 are statistically shown in Table 4.

[0134] Table 4

[0135]

[0136] The yield, grade, and recovery rate of the silicon-aluminum micropowder products of Examples 1-3 and Comparative Example 1 are statistically shown in Table 5.

[0137] Table 5

[0138]

[0139] The yield, Fe2O3 grade, and Fe2O3 recovery rate of iron concentrate in Examples 1-3 and Comparative Example 1 are statistically analyzed in Table 6.

[0140] Table 6

[0141]

[0142]

[0143] The yield, Fe2O3 grade, and Fe2O3 recovery rate of the iron-rich materials in Examples 1-3 and Comparative Example 1 are statistically analyzed in Table 7.

[0144] Table 7

[0145] Implementation Items Yield (%) <![CDATA[Fe2O3 grade (%)]]> <![CDATA[Recovery rate of Fe2O3(%)]]> Example 1 13.69 3.97 47.67 Example 2 12.42 4.21 45.87 Example 3 13.13 4.02 46.30 Comparative Example 1 19.41 2.53 43.08

[0146] As shown in Tables 2-7, compared with Comparative Example 1, Examples 1-3 have a higher recovery rate of lithium, tantalum, niobium and other substances in lithium slag. This indicates that by classifying the lithium slag suspension, lithium concentrate that meets the quality requirements of chemical-grade spodumene and high-grade tantalum and niobium concentrate can be obtained respectively. The gypsum products obtained in Examples 1-3 can be used in the building materials industry, the silica-alumina micro powder can be directly used in the ceramics industry, and the iron-rich material can be used as cement filler, thus realizing the comprehensive recycling and utilization of lithium slag.

Claims

1. A method for comprehensive recycling and utilization of lithium slag, characterized in that, Includes the following steps: 1) Pulping treatment: The lithium slag is pulped to obtain a suspension; 2) Grading treatment: The suspension obtained in step 1) is graded according to particle size to obtain coarse-grained lithium slag and fine-grained lithium slag. 3) Lithium flotation treatment: The coarse-grained lithium slag obtained in step 2) is subjected to lithium flotation treatment to obtain lithium concentrate and primary flotation tailings; 4) Grinding treatment: Grind the primary flotation tailings obtained in step 3) to obtain grinding feed; 5) Weak magnetic separation treatment: The grinding material obtained in step 4) and the fine-grained lithium slag obtained in step 2) are mixed and subjected to weak magnetic separation treatment to obtain iron concentrate and tailings after weak magnetic separation. 6) Strong magnetic separation treatment: The tailings obtained in step 5) after weak magnetic separation are subjected to strong magnetic separation treatment to obtain weak magnetic material and tailings after strong magnetic separation. 7) Re-selection process: The weakly magnetic material obtained in step 6) is subjected to re-selection process to obtain tantalum-niobium concentrate and iron-rich material; 8) Sulfur flotation treatment: The tailings obtained in step 6) after strong magnetic separation are subjected to sulfur flotation treatment to obtain silica-alumina micro powder and gypsum.

2. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 1) Pulping treatment, wherein the lithium slag is the tailings obtained after lithium extraction by spodumene sulfuric acid leaching, and the moisture content of the tailings is 15-25%.

3. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 1) Pulping treatment, wherein the slurry concentration of the suspension is 30-60%.

4. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 2) Grading process, wherein the grading adopts any one or any combination of several of the following: hydrocyclone classifier, mechanical vibration classifier, and spiral classifier.

5. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 3) Lithium flotation treatment, wherein the pulp concentration of the lithium flotation treatment is 25-40%.

6. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 3) Lithium flotation treatment, which includes the following steps: 31) Lithium slag roughing: Sodium carbonate and a roughing lithium collector are added to coarse-grained lithium slag. The amount of sodium carbonate is 100-200 g / t and the amount of the roughing lithium collector is 600-1000 g / t. Roughing treatment is carried out to obtain lithium slag roughing concentrate and lithium slag roughing tailings. 32) Primary Concentrate Refinement: Add sodium carbonate to the lithium slag rough concentrate obtained in step 31) with a dosage of 50-100 g / t, and perform primary concentrate refinement to obtain refined concentrate and primary refinement tailings. 33) Primary scavenging of tailings: Sodium carbonate and primary scavenging lithium catcher are added to the lithium slag tailings obtained from the roughing in step 31). The amount of sodium carbonate is 50-100 g / t and the amount of primary scavenging lithium catcher is 200-250 g / t. The tailings are then subjected to primary scavenging treatment to obtain primary scavenging concentrate and primary flotation tailings. 34) Middlings Concentrate Scavenging: The tailings from the primary cleaning process obtained in step 32) and the scavenged concentrate obtained in step 33) are mixed and then sodium carbonate and a lithium scavenging agent for middlings concentrate are added. The amount of sodium carbonate is 50-80 g / t and the amount of lithium scavenging agent for middlings concentrate is 100-200 g / t. Middlings concentrate scavenging is performed to obtain middlings concentrate and middlings concentrate tailings. The middlings concentrate tailings are returned to the primary scavenging process in step 33). 35) Secondary Concentrate Refinement: Sodium carbonate is added to the refined concentrate obtained in step 32) primary refinement. The amount of sodium carbonate is 20-50 g / t. Secondary concentrate refinement is carried out to obtain lithium concentrate and secondary refinement tailings. The secondary refinement tailings are combined with the middlings scavenging tailings obtained in step 34) middlings scavenging and returned to step 32) primary refinement.

7. The method for comprehensive recycling and utilization of lithium slag according to claim 6, characterized in that: The roughing lithium catcher, the primary scavenging lithium catcher, and the mid-concentrate scavenging lithium catcher are composed of dodecylamine and C. n H 2n-1 BrO2 is mixed in a molar ratio of 1:(10-20), where n represents a natural number from 10 to 18.

8. The method for comprehensive recycling and utilization of lithium slag according to claim 6, characterized in that: The C n H 2n-1 BrO2 is C n- 1H 2n-2 BrCOOH, the C n-1 H 2n-2 BrCOOH is produced by C n-1 H 2n-1 The reaction is prepared by reacting COOH with Br2 at a molar ratio of 1:1.5, wherein the reaction temperature is 70-90℃ and the reaction time is 1-3h.

9. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 4) Grinding treatment, wherein the grinding is carried out using any one or more of ball mills, vertical mills, and tower mills; the slurry concentration of the grinding material is 40-60%.

10. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 5) Weak magnetic separation treatment, with a magnetic field strength of 0.05 to 0.2 T and a pulp concentration of 20 to 30%.

11. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 6) Strong magnetic separation treatment, with a magnetic field strength of 1 to 1.5T and a pulp concentration of 10 to 20%.

12. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 7) Gravity separation, wherein the gravity separation is carried out using a shaking table and a spiral chute, and the pulp concentration of the gravity separation is 10-20%.

13. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 8) Sulfur flotation treatment, which is carried out using a flotation column, and the pulp concentration of the sulfur flotation treatment is 10-20%.

14. The method for comprehensive recycling and utilization of lithium slag according to claim 1, characterized in that: Step 8) Sulfur flotation treatment, which includes the following steps: 81) Roughing of tailings after strong magnetic separation: Add a roughing modifier and a roughing sulfur collector to the tailings after strong magnetic separation. The amount of the roughing modifier is 1500-2000 g / t and the amount of the roughing sulfur collector is 100-200 g / t. Perform roughing treatment on the tailings after strong magnetic separation to obtain roughing concentrate and roughing tailings. 82) Primary scavenging of tailings: Add a primary scavenging modifier and a primary scavenging sulfur catcher to the rough tailings obtained in step 81). The dosage of the primary scavenging modifier is 500-1000 g / t, and the dosage of the primary scavenging sulfur catcher is 50-100 g / t. Perform primary scavenging of tailings to obtain primary scavenged tailings concentrate and primary scavenged tailings. 83) Tailings Refinement: Add a refinement agent to the rough tailings obtained in step 81), the amount of which is 500-1000 g / t, and perform tailings refinement treatment to obtain gypsum and refined tailings. Return the refined tailings and the tailings concentrate obtained from the first scavenging of tailings in step 82) to the roughing of tailings after strong magnetic separation in step 81). 84) Secondary scavenging of tailings: Add a secondary scavenging modifier and a secondary scavenging sulfur collector to the tailings obtained in step 82) after primary scavenging. The amount of the secondary scavenging modifier is 300-500 g / t, and the amount of the secondary scavenging sulfur collector is 20-50 g / t. Perform secondary scavenging of tailings to obtain secondary scavenged tailings concentrate and silica-alumina micro powder. Return the secondary scavenged tailings concentrate to the primary scavenging of tailings in step 82).

15. The method for comprehensive recycling and utilization of lithium slag according to claim 14, characterized in that: The coarse screening modifier, primary scavenging modifier, fine screening modifier, and secondary scavenging modifier are all selected from any one of water glass, sulfuric acid, and sodium hydroxide.

16. The method for comprehensive recycling and utilization of lithium slag according to claim 14, characterized in that: The coarse sulfur collector, the primary scavenging sulfur collector, and the secondary scavenging sulfur collector are all selected from any one or more of the following: cocoamphoacetic acid or its salts, lauroamphoacetic acid salts, coconut oil fatty acid alanine salts, castor oil salts, oleates, and naphthenates.

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