A method for improving the grade of lepidolite concentrate

Abstract

The present invention discloses a method for improving the grade of lepidolite concentrate, which relates to the technical field of lepidolite ore dressing and includes: S1, crushing and screening the original lepidolite ore to obtain the crushed minerals; S2, adjusting the minerals in step S1 into pulp, adding a dispersant and a regulator, stirring evenly and then performing de-sludging treatment to obtain sand deposits; S3, adding water to the sand deposits obtained in step S2 to form a slurry, and adding a collector for flotation operation, wherein the collector contains oleylamine, dodecylamine, cocoamine, ethyl ether, kerosene, water and ethanol, to obtain rough concentrate and rough tailings; S4, performing cleaning on the rough concentrate obtained in step S3 to obtain the cleaned lepidolite concentrate. The beneficial effects of the present invention are that the lithium oxide grade in the lithium concentrate treated by the method of the present invention is above 3.3%, the lithium recovery rate of the single cleaned concentrate is >84%, and the overall process is relatively simple and the process is stable.

Description

Technical Field

[0001] The present invention relates to the technical field of spodumene beneficiation, and particularly relates to a method for improving the grade of spodumene concentrate. Background Art

[0002] Lithium metal, due to its light weight and high combustion temperature, is widely used in the manufacture of power batteries for new energy vehicles. With the growth of the global demand for new energy vehicles in recent years, the demand for lithium salts, the key raw materials for batteries, has been continuously increasing.

[0003] China has the world's largest associated spodumene ore resources, and spodumene is one of the most important resources for extracting lithium elements. Therefore, improving the utilization rate of spodumene resources is of great significance for promoting the high-quality development of the lithium industry. Spodumene in China, especially in Jiangxi, faces natural limitations such as complex composition and low grade, resulting in difficulties in refining and the quality of the produced lithium carbonate being difficult to reach the battery grade level. In recent years, although there have been breakthroughs in spodumene lithium extraction technology, improving the grade of spodumene concentrate remains the key point at present.

[0004] The beneficiation of spodumene mainly uses the flotation method, and many patents solve the flotation process problems of spodumene from different aspects.

[0005] The patent with the application number 201910003073.9 discloses a method for improving the grade of spodumene ore flotation concentrate. The spodumene ore is ground to 65 - 85% passing - 100 mesh, then deslimed, and then the flotation reagents are fully mixed with the pulp. One roughing and two scavenging operations are carried out, and the fineness of the grinding product is controlled. After that, one roughing and three cleaning operations are carried out. Finally, the lithium grade of the spodumene concentrate is above 3.30%, and the lithium recovery rate is above 80%. However, the steps are complex and the cost is relatively high.

[0006] The patent with the application number 202210672590.7 discloses a beneficiation method for spodumene. The spodumene raw ore is successively subjected to grinding, desliming, and pulp conditioning, then a pH adjuster and a collector are added for roughing to obtain a roughing concentrate and a roughing tailing; the roughing concentrate is subjected to cleaning to obtain a cleaning concentrate; a collector is added to the roughing tailing for scavenging to obtain a spodumene scavenging concentrate and a tailing; the collectors used include coconut amine, glacial acetic acid, octanol, and pyrrolidine. This flotation has a wide adaptation range, and the collectors used are easily dissolved and dispersed in the pulp and adsorbed on the surface of spodumene, realizing the efficient recovery of spodumene resources.

[0007] Although the above two patents have solved some problems in the flotation process, due to the lack of a dispersant in the flotation process, the distribution of mineral particles is unreasonable, the electrostatic interaction between mineral particles is strong, and it is not easy to disperse, resulting in unsatisfactory desliming effect, thus affecting the subsequent flotation effect. Summary of the Invention

[0008] The object of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method for improving the grade of lepidolite concentrate.

[0009] The technical solution of the present invention is as follows:

[0010] A method for improving the grade of lepidolite concentrate, comprising the following steps:

[0011] S1. Crushing and screening the original lepidolite ore to obtain the crushed minerals;

[0012] S2. Adjusting the minerals in step S1 into pulp, adding a dispersant and a regulator, stirring evenly and then performing desliming treatment to obtain sand deposits;

[0013] S3. Adding water to the sand deposits obtained in step S2 to form a slurry, adding a collector for flotation operation, wherein the collector comprises oleylamine, dodecylamine, cocoamine, ether, kerosene, water and ethanol, to obtain rougher concentrate and rougher tailings;

[0014] S4. Beneficiating the rougher concentrate obtained in step S3 to obtain the lepidolite beneficiated concentrate.

[0015] Preferably, in step S1, the original lepidolite ore is crushed by a jaw crusher, the outlet width of the crusher is adjusted to 4 - 10 cm, after crushing, it is screened through a 40-mesh sieve, the large-particle minerals on the sieve are returned to the jaw crusher for secondary crushing and screening, and the cycle of crushing and screening is carried out 3 - 5 times.

[0016] Preferably, in step S2, the pulp concentration is 25 - 60%, the regulator is sodium carbonate, and the addition amount of the regulator is 50 - 150 g / t.

[0017] Preferably, in step S2, the dispersant is one or more of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate, the addition amount of the dispersant is 50 - 150 g / t, and the mass ratio of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate is 2 - 7:2 - 5:1 - 3.

[0018] Preferably, in step S3, the addition amount of the collector is 150 - 600 g / t; by mass percentage, the collector comprises 20 - 30% of oleylamine, 15 - 25% of dodecylamine, 2 - 8% of cocoamine, 10 - 25% of ether, 2 - 3% of kerosene, 18 - 20% of water, and 5 - 10% of ethanol.

[0019] Preferably, in step S3, the slurry concentration is controlled to be 15 - 40%.

[0020] Preferably, in step S3, the power of the flotation machine is 120 W, the rotation speed is 1000 - 2800 r / min, the rotation speed of the scraper is 25 - 30 r / min, and the flotation time is 15 - 30 min.

[0021] Preferably, in step S4, during the cleaning process, the dosage of the collector is 0 - 150 g / t, the power of the flotation machine is 120 W, the rotation speed is 1000 - 2800 r / min, the rotation speed of the scraper is 25 - 30 r / min, and the flotation time is 15 - 30 min.

[0022] Preferably, the tailings obtained from the cleaning in step S4 are returned to step S3 for rougher separation again.

[0023] Preferably, it further includes adding a collector to the rougher separation tailings obtained in step S3 for scavenging. During scavenging, the dosage of the collector is 10 - 300 g / t, the flotation time is 20 - 40 min, and scavenged concentrate and scavenged tailings are obtained; the scavenged concentrate is returned to step S3 for rougher separation again.

[0024] The present invention has at least one of the following beneficial effects:

[0025] On the one hand, in the present invention, sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate are added as dispersants to the slurry after low - grade lepidolite is crushed and screened. After the pulp is stirred by the dispersant, the fine mud attached to the lepidolite flakes in the lepidolite mineral can be removed as much as possible, greatly improving the effect of desliming, which is beneficial to improving the subsequent flotation effect of lepidolite; on the other hand, a collector containing oleylamine, dodecylamine, cocoamine, ether, kerosene, water, and ethanol is added during flotation. Through the combined action of each component in the collector, the flotation effect can be greatly improved, so that the lithium oxide grade in the lithium concentrate treated by the method of the present invention is above 3.3%, and the lithium recovery rate of the single - cleaning concentrate > 84%, significantly improving the comprehensive utilization value of lepidolite resources; and the overall process is relatively simple, the process is stable, environmentally friendly, and has long - term and practical significance for sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow chart of a method for improving the grade of lepidolite concentrate in a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The process flow of the ore - dressing method for improving the grade of lepidolite concentrate described in the present invention is as Figure 1 shown, and it can be seen from Figure 1 that the ore - dressing method includes the following steps:

[0028] (1) Put the low-grade raw lepidolite ore into a jaw crusher for crushing. Adjust the outlet width of the crusher to 4 - 10 cm. After crushing, sieve it through a 40-mesh sieve. Return the large particles on the sieve to the jaw crusher for secondary crushing and sieving. Repeat the crushing and sieving process 3 - 5 times to obtain the ore under 40 mesh.

[0029] (2) Adjust the ore under 40 mesh obtained in step (1) into a slurry with a mass fraction of 25 - 60%. Add a dispersant and a regulator respectively, stir evenly, and pass it through a hydrocyclone for de-sludging treatment to remove the tailing slurry and obtain the sand deposit.

[0030] The dispersant is one or more of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate. The total addition amount of the dispersant is 50 - 150 g / t.

[0031] When the dispersant is a mixture of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate, the ratio of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate is 2 - 7:2 - 5:1 - 3.

[0032] The regulator is sodium carbonate, and the addition amount of the regulator is 50 - 150 g / t.

[0033] (3) Add water to the sand deposit obtained in step (2) to adjust the slurry, control the slurry concentration at 15 - 40%, add a collector for rough selection. The addition amount of the collector is 150 - 600 g / t. The power of the flotation machine is 120 W, the rotation speed is 1000 - 2800 r / min, and the rotation speed of the scraper is 25 - 30 r / min to obtain the rough concentrate and the rough tailings.

[0034] (4) Conduct cleaning on the rough concentrate obtained in step (3). The addition amount of the cleaning collector is 0 - 150 g / t to obtain the cleaned concentrate of lepidolite. The tailings obtained from cleaning are returned to step (3) for rough selection.

[0035] Continue to add a collector to the rough tailings obtained in step (3) for scavenging. The addition amount of the scavenging collector is 10 - 300 g / t to obtain the scavenged concentrate of lepidolite and the tailings. The scavenged concentrate is returned to step (3) for rough selection again.

[0036] The concentration of the cleaning slurry is 10 - 50%.

[0037] During the cleaning process, the power, rotation speed, and scraper rotation speed of the flotation machine remain unchanged, but the air inflow should be reduced; the air inflow during scavenging is increased.

[0038] The collectors described in steps (3) and (4) include oleylamine, dodecylamine, cocoamine, ethyl ether, kerosene, water, and ethanol. By mass percentage, oleylamine is 20 - 30%, dodecylamine is 15 - 25%, cocoamine is 2 - 8%, ethyl ether is 10 - 25%, kerosene is 2 - 3%, water is 18 - 20%, and ethanol is 5 - 10%.

[0039] The lithium ore described in the present invention mainly targets the Yichun lepidolite ore, and the main components in this ore are lepidolite, potassium feldspar, and quartz. Among them, the Li2O grade is between 0.2 - 0.6%, the content of symbiotic potassium feldspar is 10 - 13%, Al2O3 is 15 - 18%, and the quartz content is 60 - 70%.

[0040] Through the method of the present invention, the finally obtained lepidolite concentrate contains more than 3.3% lithium, and the lithium recovery rate is more than 84%.

[0041] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the relevant art should understand that the embodiments are only to help understand the present invention and should not be regarded as specific limitations to the present invention.

[0042] The following low-grade lepidolite raw ore is mined from Yichun City.

[0043] Example 1

[0044] (1) Put the low-grade lepidolite raw ore into a jaw crusher for crushing. The outlet width of the crusher is adjusted to 4 - 10 cm. After crushing, take an average sample to measure the metallic lithium as 0.3267%. Pass the crushed ore through a 40-mesh sieve. The minerals on the sieve are returned to the crusher for crushing and then sieved again. Repeat this process 3 times.

[0045] (2) Collect the minerals under 40 meshes, make them into a slurry with a mass fraction of 30%, add a mixture of 120 g / t of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate and 100 g / t of sodium carbonate regulator. The mass ratio of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate is 4:5:1. Pass the slurry into a hydrocyclone for desliming treatment. Discard the tailing slurry to obtain the sand.

[0046] (3) Collect the sand obtained in step (2), add water to make it into a 30% slurry, and directly add 300 g / t of collector for rough selection at normal temperature (25 - 35°C). The reaction time is 15 min. The power of the flotation machine is 120 W, the rotation speed is 2000 r / min, and the rotation speed of the scraper is 25 r / min to obtain the rough concentrate and tailings;

[0047] (4) Place the concentrate and tailings obtained in step (3) into the flotation machine for cleaning and scavenging respectively. When cleaning, add 150 g / t of collector for flotation for 15 min. The power of the flotation machine is 120 W, the rotation speed is 2000 r / min, and the rotation speed of the scraper is 25 r / min;

[0048] When scavenging, the addition amount of the collector is 50 g / t, and the flotation time is 30 min. Finally, filter and dry the slurry separated by flotation.

[0049] The weighed concentrate is 92.4g, the middlings is 26.3g, the scavenged ore is 33.23g, and the tailings is 348.13g.

[0050] The collectors described in steps (3) and (4) contain 30% oleylamine, 20% dodecylamine, 5% coconut amine, 20% ether, 2% kerosene, 18% water and 5% ethanol by mass percentage.

[0051] Table 1.1 is the test data of each component in the lepidolite ore, and Table 1.2 is the test data of each component in the lepidolite ore after flotation separation by the method of this embodiment.

[0052] Table 1.1 Test data of raw lepidolite

[0053] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.7033 5.47 4.48 17.68 71.67 ％

[0054] Table 1.2 Flotation separation results

[0055] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 500 0.3568 0.7682 -- Concentrate 92.4 1.801 3.8776 93.28 Middlings 26.3 0.417 0.8978 6.15 Scavenger concentrate 33.23 0.135 0.2907 2.51 Tailings 348.13 0.0208 0.0448 4.06

[0056] It can be seen from Table 1.1 and Table 1.2 that the metallic lithium content and lithium oxide content in the lithium mica ore of this embodiment are only 0.3267% and 0.7033% respectively. After desludging in step (2), the metallic lithium content and lithium oxide content in the sediment increase to 0.3568% and 0.7682% respectively. After roughing and concentrating in steps (3) and (4), the metallic lithium content and lithium oxide content in the concentrating concentrate increase to 1.801% and 3.8776% respectively. The lithium recovery rate is as high as 93.28%.

[0057] Example 2

[0058] (1) 0.75 kg of raw lepidolite ore was put into an orthorhombic crusher for crushing. After crushing, an average sample was taken to measure the lithium content of 0.3267%. The crushed ore was sieved through a 40-mesh sieve, and the mineral on the sieve was returned to the crusher for crushing and sieved again, and this process was repeated 3 times to obtain a mineral under 40 mesh;

[0059] (2) collecting the minerals below 40 mesh in step (1) to prepare a slurry with a mass fraction of 35%, passing the slurry into a cyclone, adding 90 g / t of a mixture of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate and 100 g / t of a sodium carbonate adjuster, the mass ratio of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate being 3:2:1, and desludging to obtain sediment;

[0060] (3) The sand collected after the desliming in step (2) is weighed, and the moisture content is measured and converted into dry weight, which is 800 g. Then, rough selection is carried out at room temperature (25 - 35 °C). During rough selection, a mixed amine collector with a dosage of 500 g / t is directly added, and stirring and flotation are carried out for 30 min. The power of the flotation machine is 120 W, the rotation speed is 2000 r / min, and the rotation speed of the scraper is 25 r / min, to obtain rough concentrate and tailings;

[0061] (4) The concentrate and tailings obtained in step (3) are respectively placed in the flotation machine for cleaning and scavenging. During cleaning, no flotation reagent is added and flotation is carried out for 15 min. The power of the flotation machine is 120 W, the rotation speed is 2000 r / min, and the rotation speed of the scraper is 25 r / min;

[0062] During scavenging, the dosage of the flotation reagent is 100 g / t and the flotation time is 30 min. Finally, the slurry separated by flotation is filtered and dried.

[0063] The weighed concentrate is 90.4 g, the middlings is 19.7 g, the scavenged concentrate is 30.23 g, and the tailings is 358.13 g.

[0064] Among them, the collector described in steps (3) and (4) contains 25% oleylamine, 25% dodecylamine, 5% coconut amine, 25% ether, 2% kerosene, 13% water, and 5% ethanol by mass percentage.

[0065] Table 2.1 shows the test data of each component in the original lepidolite ore, and Table 2.2 shows the test data of each component in the minerals after the flotation separation of the original lepidolite ore by the method of this example.

[0066] Table 2.1 Test data of the original lepidolite ore

[0067] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.7033 5.47 4.48 17.68 71.67 ％

[0068] Table 2.2 Flotation separation results

[0069] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 500 0.3568 0.7682 -- Concentrate 90.4 1.701 3.6623 86.19 Middlings 19.7 0.537 1.1562 5.93 Scavenger concentrate 30.23 0.195 0.4198 3.30 Tailings 358.13 0.0248 0.0534 4.98

[0070] It can be seen from Table 2.1 and Table 2.2 that the contents of metallic lithium and lithium oxide in the original lepidolite ore of this example are only 0.3267% and 0.7033%. After desliming in step (2), the contents of metallic lithium and lithium oxide in the sand increase to 0.3568% and 0.7682%. After rough selection and cleaning in steps (3) and (4), the contents of metallic lithium and lithium oxide in the cleaned concentrate increase to 1.701% and 3.6623%, and the recovery rate of lithium is as high as 86.19%.

[0071] Example 3

[0072] (1) 0.5 kg of raw lepidolite ore was put into an orthorhombic crusher for crushing. After crushing, an average sample was taken to measure the lithium content of 0.2860%. The crushed ore was sieved through a 40-mesh sieve, and the mineral on the sieve was returned to the crusher for crushing and sieved again, and the process was repeated 3 times to obtain a mineral powder below 40 mesh;

[0073] (2) collecting the minerals below 40 mesh obtained in step (2) to prepare a slurry with a mass fraction of 30%, passing the slurry into a cyclone, adding 80 g / t of a mixture of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate and 100 g / t of a sodium carbonate adjusting agent, wherein the mixing ratio of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate is 2:2:1, and desludging to obtain desludging and sedimentation;

[0074] (3) collecting the desludging sediment obtained in step (2), weighing and measuring the moisture content to convert it into a dry weight of 400 g, and performing roughing at room temperature (25-35° C.), directly adding 600 g / t of mixed amine collector for stirring and flotation for 30 min, the power of the flotation machine is 120 W, the rotation speed is 2000 r / min, and the speed of the scraper is 25 r / min, to obtain roughing concentrate and tailings;

[0075] (4) placing the concentrate and tailings obtained in step (3) in a flotation machine for concentrating and scavenging respectively, adding 50 g / t of flotation reagent for flotation for 15 min during concentrating, the power of the flotation machine is 120 W, the rotation speed is 2000 r / min, and the scraper rotation speed is 25 r / min;

[0076] During the sweeping process, the amount of flotation reagent added is 50g / t and the flotation time is 30min. Finally, the slurry separated by flotation is filtered and dried.

[0077] The weighed concentrate is 61.33g, the middlings is 12.34g, the scavenged ore is 6.91g, and the tailings is 318.57g.

[0078] The collectors described in steps (3) and (4) comprise, by weight percentage, 25% oleylamine, 25% dodecylamine, 5% coconut amine, 10% ether, 18% water and 17% ethanol.

[0079] Table 3.1 is the test data of each component in the lepidolite ore, and Table 3.2 is the test data of each component in the lepidolite ore after flotation separation by the method of this embodiment.

[0080] Table 3.1 Lepidolite ore test data

[0081] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.6157 7.37 6.26 15.93 69.82 ％

[0082] Table 3.2 Flotation separation results

[0083] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 400 0.2845 0.6125 -- Concentrate 61.33 1.562 3.3630 84.18 Middlings 12.34 0.8483 1.8264 9.20 Scavenger concentrate 6.91 0.188 0.4048 1.14 Tailings 318.57 0.0213 0.0459 5.96

[0084] As can be seen from Table 3.1 and Table 3.2, the contents of metallic lithium and lithium oxide in the raw lepidolite ore of this embodiment are only 0.2860% and 0.6157% respectively. After desliming in step (2), the contents of metallic lithium and lithium oxide in the sand are 0.2845% and 0.6125% respectively, slightly lower than those in the raw lepidolite ore. This may be due to detection errors, or it may be because the particle size of mica flakes in the raw lepidolite ore is very small. During desliming, some mica with fine particle size will be removed together with the tailings, resulting in a decrease in the lithium content in the sand after desliming. After rough selection and concentration in steps (3) and (4), the contents of metallic lithium and lithium oxide in the concentrated concentrate increase to 1.562% and 3.3630% respectively, and the recovery rate of lithium is as high as 84.18%.

[0085] Comparative Example 1

[0086] This comparative example provides a method for improving the grade of lepidolite concentrate. Referring to the beneficiation method described in Example 1, the difference is only that: in step (2), no dispersant is added, and desliming is directly carried out with a hydrocyclone, and the others are the same as in Example 1.

[0087] Table 4.1 Test Data of Raw Lepidolite Ore

[0088] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.7033 5.47 4.48 17.68 71.67 ％

[0089] Table 4.2 Flotation Separation Results

[0090] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 500 0.3102 0.6678 -- Concentrate 58.4 1.2021 2.5881 45.27 Middlings 27.9 0.9839 2.1183 17.70 Scavenger concentrate 48.52 0.1932 0.4160 6.04 Tailings 358.13 0.1124 0.2420 25.96

[0091] As can be seen from Table 4.1 and Table 4.2, the contents of metallic lithium and lithium oxide in the raw lepidolite ore in this comparative example are only 0.3267% and 0.7033% respectively; after desliming in step (2), the contents of metallic lithium and lithium oxide in the sand are 0.3102% and 0.6678% respectively, lower than those in the raw lepidolite ore. This may be because when no dispersant is added, the desliming by the hydrocyclone is not complete enough, resulting in some fine slime with fine particle size still adhering to the lepidolite flakes, reducing the floatability and affecting the lithium recovery rate and the lithium grade of the concentrate in flotation. After rough selection and concentration in steps (3) and (4), the contents of metallic lithium and lithium oxide in the concentrated concentrate are 1.2021 and 2.5881% respectively, and the recovery rate of lithium is only 45.27%.

[0092] Comparative Example 2

[0093] This comparative example provides a method for improving the grade of lepidolite concentrate. Referring to the beneficiation method described in Example 1, the difference is only that: in steps (2) and (3), the collector in the flotation reagent is 50% oleylamine and 50% water.

[0094] Table 5.1 Test Data of Lepidolite Raw Ore

[0095] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.7033 5.47 4.48 17.68 71.67 ％

[0096] Table 5.2 Flotation Separation Results

[0097] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 500 0.3568 0.7682 -- Concentrate 21.4 1.2021 2.5881 14.42 Middlings 10.31 1.019 2.1939 5.89 Scavenger concentrate 48.52 1.2032 2.5905 32.72 Tailings 418.13 0.2724 0.5865 63.84

[0098] It can be seen from Table 5.1 and Table 5.2 that in this comparative example, the contents of metallic lithium and lithium oxide in the lepidolite raw ore are only 0.3267% and 0.7033% respectively. After desliming in step (2), the contents of metallic lithium and lithium oxide in the sand concentrate increase to 0.3568% and 0.7682% respectively. After rough selection and cleaning in steps (3) and (4), the contents of metallic lithium and lithium oxide in the cleaned concentrate are 1.2021 and 2.5881% respectively, and the recovery rate of lithium is only 14.42%.

[0099] Comparative Example 3

[0100] This comparative example provides a method for improving the grade of lepidolite concentrate. Referring to the beneficiation method described in Example 1, the difference is only that in steps (2) and (3), the collector in the flotation reagent is 50% coconut amine and 50% water.

[0101] Table 6.1 Test Data of Lepidolite Raw Ore

[0102] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.7033 5.47 4.48 17.68 71.67 ％

[0103] Table 6.2 Flotation Separation Results

[0104] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 500 0.3568 0.7682 -- Concentrate 32.4 1.4021 3.0187 25.46 Middlings 16.21 1.019 2.1939 9.26 Scavenger concentrate 43.52 0.982 2.1142 23.96 Tailings 402.13 0.1824 0.3927 41.11

[0105] It can be seen from Table 6.1 and Table 6.2 that in this comparative example, the contents of metallic lithium and lithium oxide in the lepidolite raw ore are only 0.3267% and 0.7033% respectively. After desliming in step (2), the contents of metallic lithium and lithium oxide in the sand concentrate increase to 0.3568% and 0.7682% respectively. After rough selection and cleaning in steps (3) and (4), the contents of metallic lithium and lithium oxide in the cleaned concentrate increase to 1.4021% and 3.0187% respectively, and the recovery rate of lithium is only 25.46%.

[0106] Comparative Example 4

[0107] This comparative example provides a method for improving the grade of lepidolite concentrate. Referring to the beneficiation method described in Example 1, the difference is only that in steps (2) and (3), the collector in the flotation reagent is 50% dodecylamine and 50% water.

[0108] Table 7.1 Test Data of Lepidolite Raw Ore

[0109] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.7033 5.47 4.48 17.68 71.67 ％

[0110] Table 7.2 Flotation Separation Results

[0111] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 500 0.3568 0.7682 -- Concentrate 39.4 1.38 2.9711 30.48 Middlings 19.21 0.919 1.9786 9.90 Scavenger concentrate 39.52 0.982 2.1142 21.75 Tailings 392.13 0.1724 0.3712 37.89

[0112] As can be seen from Table 7.1 and Table 7.2, in this comparative example, the metal lithium content and lithium oxide content in the raw lepidolite ore are only 0.3267% and 0.7033% respectively. After desliming in step (2), the metal lithium content and lithium oxide content in the sand deposit increase to 0.3568% and 0.7682% respectively. After rough selection and cleaning in steps (3) and (4), the metal lithium content and lithium oxide content in the cleaned concentrate increase to 1.38% and 2.9711% respectively, and the lithium recovery rate is only 30.48%.

[0113] Comparative Example 5

[0114] This comparative example provides a method for improving the grade of lepidolite concentrate. Referring to the ore dressing method described in Example 1, the difference is only that: in steps (2) and (3), the collector in the flotation reagent is 35% oleylamine, 30% dodecylamine, 15% coconut amine, and 20% water.

[0115] Table 8.1 Test Data of Raw Lepidolite Ore

[0116] Raw material <![CDATA[Li2O]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> Unit Lepidolite ore 0.7033 5.47 4.48 17.68 71.67 ％

[0117] Table 8.2 Flotation Separation Results

[0118] Flotation minerals Mass / g Elemental lithium / % Lithium oxide / % Lithium recovery rate / % Sand after desliming 500 0.3568 0.7682 -- Concentrate 67.36 1.48 3.1864 55.88 Middlings 21.21 0.819 1.7633 9.74 Scavenger concentrate 43.52 0.872 1.8774 21.27 Tailings 362.13 0.091 0.1959 18.47

[0119] As can be seen from Table 8.1 and Table 8.2, in this comparative example, the metal lithium content and lithium oxide content in the raw lepidolite ore are only 0.3267% and 0.7033% respectively. After desliming in step (2), the metal lithium content and lithium oxide content in the sand deposit increase to 0.3568% and 0.7682% respectively. After rough selection and cleaning in steps (3) and (4), the metal lithium content and lithium oxide content in the cleaned concentrate increase to 1.48% and 3.1864% respectively, and the lithium recovery rate is only 55.88%.

[0120] Based on Examples 1-3 and Comparative Examples 1-5, the following can be obtained:

[0121] 1. As can be seen from Examples 1-3, the lithium oxide grade in the lithium concentrate treated by the method of the present invention is above 3.3%, and the lithium recovery rate of the single cleaned concentrate > 84%.

[0122] 2. By comparing Comparative Example 1 (without adding a dispersant) with Example 1, it can be seen that compared with Example 1, in Comparative Example 1, due to the absence of a dispersant, the degree of desliming of the raw ore is incomplete, and the lithium oxide grade and recovery rate of the finally obtained lepidolite concentrate are significantly lower than those in Example 1.

[0123] 3. By comparing Example 1 with Comparative Examples 2 - 5, the collectors added in Comparative Examples 2 - 5 are different from that in Example 1, resulting in the lithium oxide grade and recovery rate of the finally obtained lepidolite concentrate being significantly lower than those in Example 1. Specifically:

[0124] The collector in Comparative Example 2 is only oleylamine. Since oleylamine is insoluble in water, the lithium oxide grade and recovery rate of the lepidolite concentrate obtained in Comparative Example 2 are lower than those in Example 1.

[0125] The collector in Comparative Example 3 is only cocoamine. The solubility of cocoamine in water is also very poor, resulting in the lithium oxide grade and recovery rate of the lepidolite concentrate obtained in Comparative Example 3 being lower than those in Example 1.

[0126] The collector in Comparative Example 4 is only dodecylamine. Dodecylamine is slightly soluble in water and has poorer selectivity, resulting in the lithium oxide grade and recovery rate of the lepidolite concentrate obtained in Comparative Example 4 being lower than those in Example 1.

[0127] The collector in Comparative Example 5 does not add ethyl ether. Ethyl ether is an excellent fat-soluble solvent that can dissolve oily organic substances such as dodecylamine, oleylamine, and cocoamine, and can be miscible with water in any proportion, which is beneficial to making the reaction system more homogeneous and giving full play to the flotation performance of the reagent. As a result, the lithium oxide grade and recovery rate of the lepidolite concentrate obtained in Comparative Example 5 are lower than those in Example 1.

[0128] In summary, by selecting the appropriate types of dispersants and collectors in the present invention, the components act synergistically, so that the lithium oxide grade in the lithium concentrate of the present invention is above 3.3%, and the lithium recovery rate of the single-concentration concentrate > 84%.

[0129] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent replacements or changes, should be covered by the protection scope of the present invention.

Claims

1. A method for improving the grade of lepidolite concentrate, characterized in that, It includes the following steps: S1. Crush and screen the raw lepidolite ore to obtain the crushed mineral; S2. Adjust the mineral in step S1 into pulp, add a dispersant and a regulator, stir evenly and then carry out de-sludging treatment to obtain the sand deposit; S3. Add water to the sand deposit obtained in step S2 to make a slurry, add a collector for flotation operation, wherein the collector contains oleylamine, dodecylamine, cocoamine, ether, kerosene, water and ethanol, to obtain the rougher concentrate and the rougher tailings; S4. Carry out cleaning on the rougher concentrate obtained in step S3 to obtain the cleaned lepidolite concentrate; In step S2, the dispersant is one or more of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate. The addition amount of the dispersant is 50 - 150 g / t, and the mass ratio of sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate is 2 - 7:2 - 5:1 - 3; The addition amount of the collector is 150 - 600 g / t; by mass percentage, the collector contains 20 - 30% oleylamine, 15 - 25% dodecylamine, 2 - 8% cocoamine, 10 - 25% ether, 2 - 3% kerosene, 18 - 20% water, and 5 - 10% ethanol.

2. The method for improving the grade of lepidolite concentrate according to claim 1, characterized in that, In step S1, the raw lepidolite ore is crushed by a jaw crusher, the outlet width of the crusher is adjusted to 4 - 10 cm, and after crushing, it is screened through a 40-mesh sieve. The large-particle minerals on the sieve are returned to the jaw crusher for secondary crushing and screening, and the crushing and screening are cycled 3 - 5 times.

3. A method for improving the grade of lepidolite concentrate according to claim 1, characterized in that, In step S2, the pulp concentration is 25 - 60%, the regulator is sodium carbonate, and the addition amount of the regulator is 50 - 150 g / t.

4. A method for improving the grade of lepidolite concentrate according to claim 1, characterized in that, In step S3, the slurry concentration is controlled to be 15 - 40%.

5. A method for improving the grade of lepidolite concentrate according to claim 1, characterized in that, In step S3, the power of the flotation machine is 120 W, the rotation speed is 1000 - 2800 r / min, the rotation speed of the scraper is 25 - 30 r / min, and the flotation time is 15 - 30 min.

6. A method for improving the grade of lepidolite concentrate according to claim 1, characterized in that, In step S4, during cleaning, the addition amount of the collector is 0 - 150 g / t, the power of the flotation machine is 120 W, the rotation speed is 1000 - 2800 r / min, the rotation speed of the scraper is 25 - 30 r / min, and the flotation time is 15 - 30 min.

7. A method for improving the grade of lepidolite concentrate according to claim 1, characterized in that, The tailings obtained by cleaning in step S4 are returned to step S3 for re-roughering.

8. A method for improving the grade of lepidolite concentrate according to claim 1, characterized in that, It also includes continuing to add a collector to the rougher tailings obtained in step S3 for scavenging. During scavenging, the addition amount of the collector is 10 - 300 g / t, the flotation time is 20 - 40 min, to obtain the scavenged concentrate and the scavenged tailings; the scavenged concentrate is returned to step S3 for re-roughering.

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