A method for beneficiating lithium from a sedimentary lithium-poor clay

Abstract

The present application provides a method for beneficiating and enriching lithium from sedimentary lithium-poor clay, and belongs to the technical field of resource comprehensive utilization. The method of the present application realizes effective enrichment of lithium in the sedimentary lithium-poor clay through the steps of crushing, scrubbing and grading, in cooperation with grinding, flotation for removing calcium, flotation for removing aluminum, and flotation for removing silicon. The gangue removal rate of the sedimentary lithium-poor clay is greater than 60%, the calcium removal rate is greater than 90%, the lithium recovery rate is greater than 60%, and the lithium enrichment ratio can reach 2.34-2.8. The method of the present application is used for beneficiating and enriching the sedimentary lithium-poor clay, and has the advantages of high gangue removal rate, high lithium enrichment ratio, and low metallurgical lithium extraction cost. The process is simple and easy to realize industrialization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resource comprehensive utilization, and particularly relates to a method for beneficiating and enriching lithium from a sedimentary lithium-poor clay. BACKGROUND

[0002] Due to the vigorous support of the state to the new energy industry, the power battery industry has developed rapidly, resulting in rapid expansion of the demand for lithium. Among the lithium ore deposits found in nature, brine type, pegmatite type and sedimentary type are the three main types of ore deposits. The brine type lithium ore deposit belongs to the exogenous type lithium ore deposit, and lithium mainly exists in the form of soluble ions; the pegmatite type lithium ore belongs to the endogenous type lithium ore deposit, and lithium mainly exists in minerals such as spodumene and lepidolite. Most of the sedimentary type lithium ore has low grade, and lithium may exist in clay minerals in the form of adsorption or isomorphism, which is called sedimentary lithium clay.

[0003] The lithium resources in China mainly include spodumene (Xinjiang, Sichuan), lepidolite (Jiangxi), lithium salt lake (Qinghai, Tibet) and lithium clay (Guizhou, Yunnan). At present, there are industrialization cases of spodumene, lepidolite and lithium salt lake, but the lithium resources still cannot meet the demand of the power battery industry, so the lithium clay gradually attracts the attention of domestic researchers.

[0004] At present, the sedimentary lithium clay is usually directly subjected to a wet metallurgical method for direct lithium extraction, and through leaching, impurity removal and purification, lithium precipitation and refining, battery-grade lithium carbonate is obtained. The wet metallurgical method is suitable for the sedimentary lithium clay with high Li2O content. For the sedimentary lithium-poor clay, there are problems such as large amount of ore required per ton of lithium, large amount of slag, and large consumption of composite sulfate / sulfuric acid.

[0005] The prior art discloses a method for enriching lithium from lithium clay ore, which comprises: performing particle crushing; performing primary roughing on the raw ore by using ferric sulfate or ferric nitrate, sodium oleate and cocamine to obtain a rough concentrate and a rough tailing; performing cleaning on the rough concentrate to obtain a first part of the concentrate; performing ball milling on the rough tailing and performing primary flotation to obtain a re-milling rough concentrate and a re-milling rough tailing; performing primary flotation on the re-milling rough concentrate to obtain a second part of the concentrate; and performing primary flotation on the re-milling rough tailing to obtain a cleaning tailing. However, the method uses a plurality of types of collectors with complex components, and the enrichment ratio of the final concentrate obtained by the method is only 2.19-2.34, which still needs to be improved.

[0006] Therefore, it is necessary to propose a method for beneficiating and enriching lithium from the sedimentary lithium-poor clay, which can not only reduce the amount of metallurgical material, but also improve the lithium grade of the feed material, so as to realize effective enrichment of the sedimentary lithium-poor clay. SUMMARY

[0007] The present application aims to overcome the defects in the prior art and provide a method for beneficiating and enriching lithium from a sedimentary lithium-poor clay.

[0008] To achieve the above object, the present application adopts the following technical solutions:

[0009] A method for beneficiating and enriching lithium from a sedimentary lithium-poor clay, comprising the following steps:

[0010] S1. crushing the sedimentary lithium-poor clay to obtain fine mineral particles with a particle size of -(8-35) mm;

[0011] S2. stirring and scrubbing the fine mineral particles obtained in step S1, and then classifying them according to particle size, wherein the particles with a particle size > 2 mm are gangue, the particles with a particle size < 0.01 mm are lithium-enriched product A, and the particles with a particle size of 0.01-2 mm are intermediate particles;

[0012] S3. grinding the intermediate particles obtained in step S2 to obtain a slurry, and then using sodium hydroxide and / or sodium carbonate to condition the slurry, adding water glass, sodium hexametaphosphate, fatty acid and cocamide to the slurry, and then performing flotation to remove calcium to obtain tailings A;

[0013] S4. using water glass and / or sodium hexametaphosphate to condition the tailings A obtained in step S3, adding fatty acid, and then performing flotation to remove aluminum to obtain tailings B;

[0014] S5. using a pH adjuster to adjust the pH of the tailings B obtained in step S4 to 3-4, adding cocamide, and then performing flotation to remove silicon to obtain lithium-enriched product B;

[0015] S6. the lithium-enriched product A obtained in step S2 and the lithium-enriched product B obtained in step S5 are lithium-rich products.

[0016] It should be noted that in this application, the plus or minus sign in the particle size indicates whether the size of the sieve hole can be passed or not; a negative number indicates that it can all pass through the size of the sieve hole, and a positive number indicates that it cannot pass through the size of the sieve hole. For example, fine mineral particles with a particle size of -(8-35) mm can all pass through a sieve hole with a size of 8-35 mm.

[0017] In the method for beneficiating and enriching lithium according to the present application, through the steps of crushing, scrubbing and classifying, in combination with grinding, flotation to remove calcium, flotation to remove aluminum and flotation to remove silicon, the lithium in the sedimentary lithium-poor clay is effectively enriched, and the lithium enrichment ratio can reach 2.34-2.8.

[0018] During the crushing and scrubbing and classifying in steps S1 and S2, based on the particle size characteristics of the sedimentary lithium-poor clay, selective crushing and classifying are performed to achieve the purpose of throwing away calcium-containing gangue under the condition of single scrubbing.

[0019] In the process of reverse floatation and impurity removal (grinding, floatation and calcium removal, floatation and aluminum removal, floatation and silicon removal), the types of reagents are reasonably selected, the reagents belong to the same system, and there is no mutual negative influence between the reagents. In addition to achieving efficient removal of calcium, aluminum, silicon and other impurities in the sedimentary lithium-poor clay, the mixed recycling of the calcium-removal and aluminum-removal backwater is also achieved, and no backwater interference is generated. In the floatation and calcium removal of step S3, sodium hydroxide and / or sodium carbonate are used as the conditioning agent, water glass and / or sodium hexametaphosphate are used as the depressor, and fatty acid and coconut amine are used as the collector; in the floatation and aluminum removal of step S4, water glass and / or sodium hexametaphosphate are used as the conditioning agent, and fatty acid is used as the collector; and in the floatation and silicon removal of step S5, coconut amine is used as the collector.

[0020] In the process of floatation and silicon removal in step S5, the pH of the system is controlled to be 3-4, i.e. a medium-strength acidic condition. The acid consumption is saved, the corrosion to the equipment is reduced, and a high silicon removal efficiency is achieved, thereby obtaining an excellent lithium enrichment ratio.

[0021] Preferably, the floatation and calcium removal, the floatation and aluminum removal, and the floatation and silicon removal each include once roughing, twice scavenging and once cleaning.

[0022] It should be noted that in the present application, the tailings A in step S3 are the tank bottom products generated in the scavenging and cleaning in the process of floatation and calcium removal, and the cleaning froth is calcium-containing gangue; the tailings B in step S4 are the tank bottom products generated in the scavenging and cleaning in the process of floatation and aluminum removal, and the cleaning froth is diaspore; and the lithium enrichment B in step S5 is the tank bottom product generated in the scavenging and cleaning in the process of floatation and silicon removal, and the cleaning froth is quartz impurity.

[0023] Preferably, in step S3, the addition amount of sodium hydroxide is 500-3000 g / t based on the mass of the intermediate particles, the addition amount of sodium carbonate is 1000-6000 g / t, the addition amount of water glass is 1000-4000 g / t, the addition amount of sodium hexametaphosphate is 50-200 g / t, the addition amount of fatty acid is 1000-4000 g / t, and the addition amount of coconut amine is 100-300 g / t.

[0024] In the floatation and calcium removal, the combination of sodium hydroxide and sodium carbonate is used as the conditioning agent, which has the advantages of simple pH adjustment and good buffering performance. When the sedimentary lithium-poor clay contains little mud, sodium carbonate can be used alone; when the sedimentary lithium-poor clay contains little alkaline or acidic mineral, sodium hydroxide can be used alone.

[0025] Preferably, in step S3, the weight ratio of coconut amine to fatty acid is (1-3) : 10.

[0026] Preferably, in step S4, the water glass is added in an amount of 1000-4000 g / t, the sodium hexametaphosphate is added in an amount of 50-200 g / t, and the fatty acid is added in an amount of 500-1500 g / t, based on the mass of the intermediate particles.

[0027] Preferably, in step S5, the cocamine is added in an amount of 50-150 g / t, based on the mass of the intermediate particles.

[0028] The sedimentary lithium-lean clay mainly comprises lithium-containing minerals, calcium-containing gangue, aluminum-containing impurities, and silicon-containing impurities. The lithium-containing minerals are mainly chlorotoid, with a mass percentage of 30-50%; the calcium-containing gangue is mainly calcite and / or dolomite, with a mass percentage of 20-40%; the aluminum-containing impurities are mainly monohydrate, with a mass percentage of 10-15%; and the silicon-containing impurities are mainly quartz, with a mass percentage of 15-40%.

[0029] Preferably, in step S2, the stirring and scrubbing are performed under the following conditions: a concentration of 50-80 wt.%, a stirring speed of 500-1500 rpm, and a scrubbing time of 5-15 min.

[0030] Preferably, in step S2, the classification treatment adopts vibration classification and hydrocyclone classification. The vibration classification can adopt a multi-layer vibrating screen to obtain a +0.2 mm size fraction; and the hydrocyclone classification can adopt a hydrocyclone to obtain a -0.2 mm size fraction.

[0031] Preferably, in step S3, the mass percentage of particles with a particle size of -0.074 mm in the ore slurry is 70-90%.

[0032] The mass percentage of particles with a particle size of -0.074 mm in the ore slurry is 70-90%, indicating that the weight percentage of particles that pass through a 0.074 mm sieve in the ore slurry is 70-90%.

[0033] In step S5, the pH regulator can be an inorganic acid or an organic acid that can generate H + .

[0034] Preferably, in step S5, the pH regulator is at least one of sulfuric acid, phosphoric acid, hydrochloric acid, and hydrofluoric acid.

[0035] More preferably, in step S5, the pH regulator is sulfuric acid.

[0036] By the beneficiation method for enriching lithium according to the present application, the gangue removal rate is >60%, the calcium removal rate is >90%, the lithium recovery rate is >60%, and the lithium enrichment ratio is ≥2.34.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] The present application provides a method for beneficiating lithium from sedimentary lithium-poor clay, through the steps of crushing, scrubbing, grading, in combination with grinding, flotation for removing calcium, flotation for removing aluminum, and flotation for removing silicon, to achieve effective enrichment of lithium in the sedimentary lithium-poor clay, with gangue removal rate >60%, calcium removal rate >90%, lithium recovery rate >60%, and lithium enrichment ratio 2.34-2.8. The method of the present application is simple and easy to realize industrialization, and is beneficial to reducing the cost of metallurgical lithium extraction. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The figure is a flowchart of the method for beneficiating lithium from sedimentary lithium-poor clay according to the present application.

[0040] Figure 2 The figure is a flowchart of the flotation process for removing calcium, aluminum and silicon according to the present application. DETAILED DESCRIPTION

[0041] For the purpose of better illustrating the object, technical scheme and advantages of the present application, the present application will be further described below in conjunction with specific examples and drawings, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and devices used in the present application are conventional reagents, methods and devices in the technical field. Unless otherwise specified, the reagents and materials used in the present application are commercially available.

[0042] Example 1

[0043] The present example provides a method for beneficiating lithium from sedimentary lithium-poor clay.

[0044] The grade of each main component in the sedimentary lithium-poor clay of the present example is: Li2O 0.52%, Ca 14.73%, Al 7.55%, Si 11.30%, wherein the grade refers to the content of the component.

[0045] The method of the present example comprises the following steps:

[0046] S1. Selectively crushing the sedimentary lithium-poor clay to obtain fine mineral particles with particle size of -8mm (all passing through a sieve hole of 8mm);

[0047] S2. Stir scrubbing of fine mineral particles, pulp mass concentration 80%, stirring speed (scrubbing intensity) 500 rpm, scrubbing time 5 min, after scrubbing, vibration screen classification, classification particle size upper limit 2.0 mm; particle size greater than the classification particle size upper limit is directly discarded as gangue, +2 mm particle size yield 51.33%, containing Li2O 0.12%, Ca 21.12%, Li2O loss rate 11.93%, Ca removal rate 77.09%;

[0048] The particle size below the vibration screen enters the hydrocyclone group, and -0.038 mm particle size is separated out and directly used as lithium concentrate A, with a yield of 30.35%, containing Li2O 1.27%, 4.02%, Li2O recovery rate 74.47%.

[0049] The classified intermediate particle size (-2.0+0.038 mm) is used as an intermediate particle for subsequent reverse flotation and impurity removal;

[0050] S3. Grinding of the intermediate particle, controlling the fineness of -0.074 mm to be 70%, and then performing flotation and calcium removal: adding conditioning agent sodium hydroxide 500 g / t + sodium carbonate 1000 g / t for pulp conditioning, adding depressant water glass 1000 g / t (700 g / t for roughing and 300 g / t for cleaning) + sodium hexametaphosphate 50 g / t (50 g / t for roughing), adding fatty acid 1000 g / t (500 g / t for roughing, 250 g / t for first scavenging, and 250 g / t for second scavenging) + cocamide 100 g / t (50 g / t for roughing, 25 g / t for first scavenging, and 25 g / t for second scavenging), through one roughing, two scavenging, and one cleaning, the cleaning froth is used as calcium-containing gangue, with a yield of 8.99%, containing Li2O 0.25%, Ca 22.79%, Li2O loss rate 4.42%, and the tank bottom product of cleaning and scavenging is tailings A, which enters the flotation and aluminum removal operation;

[0051] S4. Flotation and aluminum removal: adding conditioning agent water glass 1000 g / t + sodium hexametaphosphate 50 g / t, adding fatty acid 500 g / t (300 g / t for roughing, 150 g / t for first scavenging, and 50 g / t for second scavenging), through one roughing, two scavenging, and one cleaning, the cleaning froth is used as diaspore, with a diaspore impurity yield of 4.20%, containing Li2O 0.11%, Al 23.11%, Li2O loss rate 0.92%, and the tank bottom product of cleaning and scavenging is tailings B, which enters the flotation and silicon removal operation;

[0052] S5. Floatation desilication: add sulfuric acid to adjust the pH of the slurry to 3, add coconut amine as collector 50 g / t (30 g / t for rough selection, 10 g / t for first scavenging, 10 g / t for second scavenging), and after one rough selection, two scavengings and one cleaning, the foam of the cleaning is the quartz impurities, the yield of the quartz impurities is 2.31%, containing Li2O 0.19%, Si 38.93%, the loss rate of Li2O is 0.83%, and the bottom product of the cleaning and scavenging is combined as the lithium concentrate B;

[0053] S6. The lithium concentrate A obtained in step S2 and the lithium concentrate B obtained in step S5 are the lithium-rich products.

[0054] In this embodiment, the impurity removal rate is 66.83%, the calcium removal rate is 91.05%, the lithium recovery rate is 81.91%, and the lithium enrichment ratio is 2.47.

[0055] Example 2

[0056] The embodiment provides a method for beneficiating and enriching lithium from a sedimentary lithium-poor clay.

[0057] The grade of each main component in the sedimentary lithium-poor clay of the embodiment is: Li2O 0.39%, Ca 9.26%, Al 10.05%, and Si 12.13%, wherein the grade refers to the content of the component.

[0058] The method of the embodiment comprises the following steps:

[0059] S1. Selectively crushing the sedimentary lithium-poor clay so that the particle size of the crushed product is-15 mm (all passing through a sieve hole of 15 mm), to obtain fine mineral particles;

[0060] S2. Stirring and scrubbing the fine mineral particles, with a slurry mass concentration of 65%, a stirring speed (scrubbing intensity) of 1000 rpm, and a scrubbing time of 10 min, and then performing vibration screening grading, with an upper limit of the grading particle size being 0.83 mm; the particle size greater than the upper limit of the grading particle size is directly discarded as gangue, the yield of the +0.83 mm particle size fraction is 24.62%, containing Li2O 0.12%, Ca 23.02%, the loss rate of Li2O is 7.78%, and the calcium removal rate is 61.19%;

[0061] The particle size fraction below the vibration screen enters a hydrocyclone group, and the-0.01 mm particle size fraction is separated out and directly used as the lithium concentrate A, with a yield of 5.59%, containing Li2O 0.49%, Ca 3.55%, and a lithium recovery rate of 7.11%.

[0062] The intermediate particle size fraction (-0.83+0.010 mm) of the grading is used as the intermediate particles, and subsequent reverse floatation and impurity removal are performed.

[0063] S3. The intermediate particles are ground to control the fineness of -0.074 mm to 90%, and then subjected to flotation decalcification: adjusting agent sodium hydroxide 3000 g / t + sodium carbonate 6000 g / t is added for conditioning, inhibitor water glass 4000 g / t (3500 g / t for rough selection, 500 g / t for fine selection) + sodium hexametaphosphate 200 g / t (150 g / t for rough selection, 50 g / t for fine selection) is added, fatty acid 4000 g / t (2000 g / t for rough selection, 1000 g / t for first scavenging, 1000 g / t for second scavenging) + coconut amine 300 g / t (200 g / t for rough selection, 50 g / t for first scavenging, 50 g / t for second scavenging) is added, and after one rough selection, two scavengings and one fine selection, the fine selection froth is taken as the calcium-containing gangue, with a yield of 22.05%, Li2O content of 0.27%, Ca content of 13.65%, Li2O loss rate of 15.66%, and the tank bottom product of fine selection and scavenging is tailings A, which is subjected to flotation dealumination operation;

[0064] S4. Flotation dealumination: adjusting agent water glass 4000 g / t + sodium hexametaphosphate 200 g / t is added, fatty acid 1500 g / t (800 g / t for rough selection, 500 g / t for first scavenging, 200 g / t for second scavenging) is added, and after one rough selection, two scavengings and one fine selection, the fine selection froth is taken as diaspore, with a yield of 16.71% of diaspore impurities, Li2O content of 0.16%, Al content of 20.19%, Li2O loss rate of 6.95%, and the tank bottom product of fine selection and scavenging is tailings B, which is subjected to flotation desilication operation;

[0065] S5. Flotation desilication: sulfuric acid is added to adjust the pH of the slurry to 3.3, and coconut amine is added as collector 100 g / t (70 g / t for rough selection, 20 g / t for first scavenging, 10 g / t for second scavenging), and after one rough selection, two scavengings and one fine selection, the fine selection froth is taken as quartz impurities, with a yield of 13.96% of quartz impurities, Li2O content of 0.17%, Si content of 27.75%, Li2O loss rate of 6.25%, and the tank bottom product of fine selection and scavenging is combined as lithium concentrate B;

[0066] S6. The lithium concentrate A obtained in step S2 and the lithium concentrate B obtained in step S5 are taken as the lithium-rich product.

[0067] In this embodiment, the impurity removal rate is 77.34%, the calcium removal rate is 94.04%, the lithium recovery rate is 63.36%, and the lithium enrichment ratio is 2.80.

[0068] Example 3

[0069] The embodiment provides a method for beneficiating and enriching lithium from a sedimentary type lithium-poor clay.

[0070] The grade of each main component in the sedimentary lithium-lean clay of the embodiment is: Li2O 0.52%, Ca 9.21%, Al 9.95%, Si 11.30%, wherein the grade refers to the component content.

[0071] The method of the embodiment comprises the following steps:

[0072] S1. The sedimentary lithium-lean clay is selectively crushed, so that the particle size of the crushed product is-35 mm (all passes through a sieve hole of 35 mm), to obtain fine ore particles;

[0073] S2. The fine ore particles are stirred and scrubbed, the pulp mass concentration is 50%, the stirring speed (scrubbing intensity) is 1500 rpm, the scrubbing time is 15 min, and after the scrubbing is completed, vibration screening is performed for classification, and the upper limit of the classified particle size is 0.83 mm; the particle size greater than the upper limit of the classified particle size is directly discarded as gangue, the yield of the +0.83 mm particle size fraction is 22.14%, contains Li2O 0.13%, Ca2 0.03%, the loss rate of Li2O is 5.62%, and the removal rate of Ca is 48.16%.

[0074] The particle size fraction below the vibration screen enters a hydrocyclone group, and a-0.02 mm particle size fraction is separated out and directly used as lithium concentrate A, the yield of which is 30.35%, contains Li2O 1.27%, and the recovery rate of Li2O is 74.47%.

[0075] The intermediate particle size fraction (-0.83+0.02 mm) classified is used as an intermediate particle and is subjected to subsequent reverse flotation and gangue removal.

[0076] S3. The intermediate particle is ground, and the fineness of-0.074 mm is controlled to be 80%, and then flotation is performed for calcium removal: 2000 g / t of sodium hydroxide + 4000 g / t of sodium carbonate are added for pulp conditioning, 3000 g / t of water glass (2000 g / t for rough selection and 1000 g / t for fine selection) + 150 g / t of sodium hexametaphosphate (100 g / t for rough selection and 50 g / t for fine selection) are added as depressants, 3000 g / t of fatty acid (1500 g / t for rough selection, 1000 g / t for primary scavenging, and 500 g / t for secondary scavenging) + 200 g / t of cocamide (100 g / t for rough selection, 50 g / t for primary scavenging, and 50 g / t for secondary scavenging) are added, and after one rough selection, two scavengings, and one fine selection, the foam of the fine selection is used as calcium-containing gangue, the yield of which is 18.52%, contains Li2O 0.081%, Ca 14.24%, the loss rate of Li2O is 2.92%, and the tank bottom product of the fine selection and the scavenging is tailings A, which is subjected to flotation for aluminum removal.

[0077] S4. Flotation de-alumination: adding regulator water glass 2000 g / t + sodium hexametaphosphate 150 g / t, adding fatty acid 1000 g / t (500 g / t for roughing, 300 g / t for first scavenging, 200 g / t for second scavenging), one roughing, two scavengings and one cleaning, the cleaning froth is diaspore, the diaspore impurity yield is 14.04%, containing Li2O 0.25%, Al 27.21%, the loss rate of Li2O is 6.68%, the tank bottom product of cleaning and scavenging is tailings B, which enters the flotation desilication operation;

[0078] S5. Flotation desilication: adding sulfuric acid to adjust the pH of the slurry to 4, adding coconut amine as collector 50 g / t (30 g / t for roughing, 10 g / t for first scavenging, 10 g / t for second scavenging), one roughing, two scavengings and one cleaning, the cleaning froth is quartz impurity, the quartz impurity yield is 11.73%, containing Li2O 0.26%, Si 27.47%, the loss rate of Li2O is 6.01%, the tank bottom product of cleaning and scavenging is combined as lithium concentrate B;

[0079] S6. The lithium concentrate A obtained in step S2 and the lithium concentrate B obtained in step S5 are the lithium-rich product.

[0080] In this embodiment, the impurity removal rate is 66.42%, the calcium removal rate is 93.99%, the lithium recovery rate is 78.77%, and the lithium enrichment ratio is 2.34.

[0081] Example 4

[0082] This embodiment provides a method for beneficiating and enriching lithium from a sedimentary lithium-poor clay. Except for step S3, the remaining steps are consistent with example 3.

[0083] Step S3. The intermediate particles are ground to a fineness of 80% passing -0.074 mm, and then subjected to flotation de-calcification: adding regulator sodium hydroxide 2000 g / t + sodium carbonate 4000 g / t for slurry conditioning, adding depressant water glass 3000 g / t (2000 g / t for roughing, 1000 g / t for cleaning) + sodium hexametaphosphate 150 g / t (100 g / t for roughing, 50 g / t for cleaning), adding fatty acid 2500 g / t (1500 g / t for roughing, 600 g / t for first scavenging, 400 g / t for second scavenging) + coconut amine 700 g / t (400 g / t for roughing, 200 g / t for first scavenging, 100 g / t for second scavenging), one roughing, two scavengings and one cleaning, the cleaning froth is calcium-containing gangue, the yield is 18.06%, containing Li2O 0.072%, Ca 15.53%, the loss rate of Li2O is 2.51%, the tank bottom product of cleaning and scavenging is tailings A, which enters the flotation de-alumination operation;

[0084] In this embodiment, the impurity removal rate is 66.31%, the calcium removal rate is 95.84%, the lithium recovery rate is 76.08%, and the lithium enrichment ratio is 2.41.

[0085] Example 5

[0086] This embodiment provides a method for beneficiating lithium from a sedimentary lithium-poor clay. In addition to step S3, the remaining steps are consistent with example 3.

[0087] Step S3. The intermediate particles are ground to a fineness of -0.074 mm of 80%, and then calcium is removed by flotation: conditioning agents sodium hydroxide 2000 g / t + sodium carbonate 4000 g / t are added, depressants water glass 3000 g / t (2000 g / t for roughing, 1000 g / t for cleaning) + sodium hexametaphosphate 150 g / t (100 g / t for roughing, 50 g / t for cleaning) are added, fatty acids 2900 g / t (1500 g / t for roughing, 900 g / t for first scavenging, 500 g / t for second scavenging) are added, and cocamide 300 g / t (150 g / t for roughing, 100 g / t for first scavenging, 50 g / t for second scavenging) are added, and after one roughing, two scavengings, and one cleaning, the cleaning froth is taken as calcium-containing gangue, with a yield of 19.03%, containing Li2O 0.65%, Ca 15.23%, and a Li2O loss rate of 2.35%, and the bottom products of the cleaning and scavenging are combined as tailings A, which are subjected to flotation for aluminum removal;

[0088] In this embodiment, the impurity removal rate is 66.93%, the calcium removal rate is 96.85%, the lithium recovery rate is 76.30%, and the lithium enrichment ratio is 2.45.

[0089] According to examples 3-5, in step S3, when the weight ratio of cocamide to fatty acid is (1-3): 10, the content of cocamide is relatively more, the amount of froth is larger, and more lithium is entrained, so the lithium recovery rate is slightly lower, the calcium removal rate is higher, and the lithium enrichment ratio is relatively higher.

[0090] Comparative Example 1

[0091] This comparative example provides a method for beneficiating lithium from a sedimentary lithium-poor clay. In addition to flotation for silicon removal, the remaining steps are consistent with example 3.

[0092] Flotation for silicon removal: sulfuric acid is added to adjust the pH of the ore slurry to 1.5, and cocamide is added as a collector at 50 g / t (30 g / t for roughing, 10 g / t for first scavenging, 10 g / t for second scavenging), and after one roughing, two scavengings, and one cleaning, the cleaning froth is taken as quartz impurities, with a yield of 9.12%, containing Li2O 0.27%, Si 28.73%, and a Li2O loss rate of 4.81%, and the bottom products of the cleaning and scavenging are combined as lithium enrichment B.

[0093] In the present comparative example, the impurity removal rate is 63.83%, the calcium removal rate is 94.49%, the lithium recovery rate is 79.97%, and the lithium enrichment ratio is 2.21.

[0094] As can be seen from Comparative Example 1, adjusting the slurry to a lower slurry pH does not significantly improve the enrichment index, and instead, because the gangue is carbonate, a large amount of sulfuric acid is consumed, which not only causes difficulties in equipment corrosion and reagent addition, but also leads to a higher reagent cost.

[0095] Comparative Example 2

[0096] The present comparative example provides a method for beneficiating lithium from a sedimentary lithium-poor clay. Except for the flotation desilication, the remaining steps are consistent with Example 3.

[0097] Flotation desilication: sulfuric acid is added to adjust the slurry pH to 4.3, and coconut amine is added as a collector at 50 g / t (30 g / t for roughing, 10 g / t for primary scavenging, and 10 g / t for secondary scavenging), and after one roughing, two scavengings, and one cleaning, the cleaning froth is used as the quartz impurities, the quartz impurities yield is 8.38%, the Li2O content is 0.36%, the Si content is 24.07%, the Li2O loss rate is 5.83%, and the cleaning and scavenging tank bottom products are combined as lithium enrichment B.

[0098] In the present comparative example, the impurity removal rate is 63.07%, the calcium removal rate is 91.82%, the lithium recovery rate is 78.98%, and the lithium enrichment ratio is 2.21.

[0099] As can be seen from Comparative Example 2, when the slurry pH is higher than 4 in step S5, the removal of impurities and the enrichment of lithium are less effective.

[0100] Comparative Example 3

[0101] The present comparative example provides a method for beneficiating lithium from a sedimentary lithium-poor clay, which, compared with Example 3, increases a desulfurization step before the flotation decalcification in step S3, and the remaining steps are consistent with Example 3. Specifically, the step S3 of the present comparative example is:

[0102] Step S3. The intermediate particles are ground to a fineness of 80% passing -0.074 mm, and then desulfurization is performed:

[0103] The reagents used are an acidic pH regulator (sulfuric acid, 3500 g / t), an inhibitor (starch, 150 g / t), a frother (No. 2 oil, 200 g / t), and a sulfur carbon collector (butyl xanthate, 600 g / t), and after one roughing, two scavengings, and one cleaning, the cleaning froth is used as the (sulfur impurities), the impurity yield is 6.25%, the Li2O content is 1.02%, the Si content is 14.25%, the Li2O loss rate is 12.34%, and the cleaning and scavenging tank bottom products enter the flotation decalcification;

[0104] Flotation decalcification: adding conditioning agent sodium hydroxide 2000 g / t + sodium carbonate 4000 g / t, adding depressor water glass 3000 g / t (2000 g / t for rough selection, 1000 g / t for fine selection) + sodium hexametaphosphate 150 g / t (100 g / t for rough selection, 50 g / t for fine selection), adding fatty acid 3000 g / t (1500 g / t for rough selection, 1000 g / t for first scavenging, 500 g / t for second scavenging) + cocamide 200 g / t (100 g / t for rough selection, 50 g / t for first scavenging, 50 g / t for second scavenging), through rough selection, two times of scavenging and one time of fine selection, the foam of fine selection is the calcium-containing gangue, the yield is 18.52%, Li2O content is 0.081%, Ca content is 14.24%, Li2O loss rate is 2.92%, the bottom product of fine selection and scavenging is tailings A, which enters the flotation dealuminization operation.

[0105] In the present example, the impurity removal rate is 63.25%, the calcium removal rate is 91.85%, the lithium recovery rate is 76.48%, and the lithium enrichment ratio is 2.18. When the flotation return water produced in the present example is reused, the yield of the desulfurization operation increases and the lithium loss rate is too large due to the presence of fatty acid in the water.

[0106] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for beneficiating and enriching lithium from sedimentary lithium-poor clay, characterized in that, Includes the following steps: S1. The sedimentary lithium-poor clay is crushed to obtain fine mineral particles with a particle size of -(8~35)mm; S2. Stir and scrub the fine mineral particles obtained in step S1, and then classify them according to their particle size. Particles with a particle size > 2 mm are gangue, particles with a particle size < 0.01 mm are lithium enrichment A, and particles with a particle size of 0.01 to 2 mm are intermediate particles. S3. Grind the intermediate particles obtained in step S2 to obtain a slurry. Adjust the slurry with sodium hydroxide and / or sodium carbonate, add water glass, sodium hexametaphosphate, fatty acid and coconut oil amine, and perform flotation decalcification to obtain tailings A. S4. The tailings A obtained in step S3 are slurried with water glass and / or sodium hexametaphosphate, fatty acids are added, and flotation is performed to remove aluminum to obtain tailings B. S5. Adjust the pH of the system to 3-4 using a pH adjuster for the tailings B obtained in step S4, add coconut oil amine, and perform flotation desilication to obtain lithium-enriched product B. S6. Lithium-enriched product A obtained in step S2 and lithium-enriched product B obtained in step S5 are lithium-rich products. In step S3, based on the mass of the intermediate particles, the amount of sodium hydroxide added is 500-3000 g / t, the amount of sodium carbonate added is 1000-6000 g / t, the amount of water glass added is 1000-4000 g / t, the amount of sodium hexametaphosphate added is 50-200 g / t, the amount of fatty acid added is 1000-4000 g / t, and the amount of cocoaluminamine added is 100-300 g / t.

2. The method for enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, The flotation decalcification, flotation dealuminization, and flotation desiliconization processes all include one roughing stage, two scavenging stages, and one cleaning stage.

3. The method for enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, In step S3, the weight ratio of coconut oil amine to fatty acid is (1-3):

10.

4. The method for enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, In step S4, based on the mass of the intermediate particles, the amount of water glass added is 1000-4000 g / t, the amount of sodium hexametaphosphate added is 50-200 g / t, and the amount of fatty acid added is 500-1500 g / t.

5. The method for beneficiating and enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, In step S5, the amount of coconut oil amine added is 50-150 g / t, based on the mass of the intermediate particles.

6. The method for enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, In step S2, the conditions for stirring and scrubbing are: concentration 50-80 wt.%, stirring speed 500-1500 rpm, and scrubbing time 5-15 min.

7. The method for enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, In step S3, the mass percentage of particles with a size of -0.074 mm in the slurry is 70-90%.

8. The method for enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, In step S2, the grading process employs vibration grading and hydrocyclone grading.

9. The method for enriching lithium from sedimentary lithium-poor clay according to claim 1, characterized in that, In step S5, the pH adjuster is sulfuric acid.

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