Efficient separation method for low-grade iron lepidolite ore

Abstract

The efficient separation method comprises the following steps that the low-grade iron lepidolite ore with the lithium oxide grade being 0.1%-0.3% is taken, the low-grade iron lepidolite ore with the lithium oxide grade being 0.1%-0.3% is crushed and then coarsely ground till the particle size is-0.6 mm, coarsely ground ore is obtained, and the proportion of the coarsely ground ore with the particle size being-0.6 mm + 0.3 mm is 50%-55%; modified water glass is adopted for stirring and dispersing the roughly-ground minerals, then a high-background magnetic separator with the background magnetic field intensity being 2-4 T is adopted for first-stage magnetic separation pre-enrichment, lepidolite rough concentrate is obtained, and tailing materials are removed; and regrinding the lepidolite rough concentrate product to obtain reground minerals, and carrying out flotation purification on the reground minerals to obtain a lepidolite flotation concentrate product and a flotation tailing product. After rough grinding, a high-background magnetic field strong magnetic separation method is adopted for pre-enrichment, a large number of siliceous nonmetallic minerals such as muscovite, sericite, quartz and feldspar with the surface properties similar to those of lepidolite are removed, and the follow-up flotation operation handling capacity and reagent cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ore dressing, in particular to a high-efficiency separation method for low-grade lepidolite ore. Background Art

[0002] With the continuous development of the new energy industry, the demand and price of lithium carbonate required as a positive electrode material have continued to rise, resulting in an increasing demand for lithium mineral resources year by year. With the gradual development of high-quality lithium mineral resources, it is of great significance to carry out research and development of technologies for the development and utilization of low-grade and difficult-to-separate lepidolite mineral resources. During the formation of some lepidolite ores, metal ions such as iron and manganese enter the mineral lattice, significantly causing the lithium oxide grade in the lepidolite to decrease, which significantly increases the cost of producing lithium carbonate from this type of high-iron lepidolite resource. In order to reduce the development and utilization cost of low-grade iron lepidolite ores, it is urgent to carry out research on short-process and efficient separation methods for this type of lithium mineral resources.

[0003] At present, the main beneficiation process for lepidolite with a lithium oxide grade below 0.3% is the grinding-desliming-direct flotation process. Due to the low grade of this type of lepidolite, fine grinding and multi-stage concentration processes are usually required to obtain a higher concentrate grade. In addition, due to the small differences in the surface properties of minerals such as lepidolite, muscovite and biotite, it is difficult to obtain high-grade lithium concentrate products using a single flotation process. In addition, the fine grinding operation leads to a significant increase in mud content, and the desliming operation significantly increases the amount of lithium loss. Summary of the Invention

[0004] The present invention proposes an efficient separation method for low-grade lepidolite ore. After coarse grinding, a high-background magnetic field strong magnetic separation method is used for pre-enrichment, thereby removing a large amount of siliceous non-metallic minerals such as muscovite, sericite, quartz and feldspar with surface properties similar to lepidolite, thereby reducing the subsequent flotation operation processing volume and reagent costs.

[0005] The technical solution of the present invention is achieved as follows: a method for efficiently separating low-grade lepidolite ore, comprising the following steps:

[0006] (1) taking a low-grade iron lithium mica ore with a lithium oxide grade of 0.1%-0.3%, crushing and coarse-grinding it to a particle size of -0.6 mm to obtain a coarse-ground mineral, wherein the particle size of -0.6 mm+0.3 mm accounts for 50-55% of the coarse-ground mineral;

[0007] (2) using modified water glass to stir and disperse the coarsely ground minerals, and then using a high background magnetic separator with a background magnetic field strength of 2-4T to perform a magnetic separation pre-enrichment to obtain a lepidolite coarse concentrate with a yield of 20%-30% and a lithium oxide grade of 0.5%-1.2%, and removing 70%-80% of the tailings material with a lithium oxide grade of less than 0.05%, and the lithium recovery rate of the magnetic separation operation is greater than 92%;

[0008] (3) Regrinding the lepidolite coarse concentrate product to obtain regrinded minerals, and flotation-purifying the regrinded minerals to obtain lepidolite flotation concentrate products and flotation tailings products.

[0009] Furthermore, in step (2), the synthesis method of modified water glass is as follows: water glass, citric acid and phosphoric acid are mixed in a mass ratio of 5:1:1, heated and stirred for reaction for 1-2 hours, and the reaction temperature is controlled to be 80-100°C. After the reaction is completed, modified water glass is obtained.

[0010] Furthermore, in step (2), the amount of modified water glass is 500-1000 g / t.

[0011] Furthermore, in step (3), the grinding fineness of the regrinding operation is -0.1 mm, accounting for 30%-50%.

[0012] Furthermore, in step (3), the flotation operation method is as follows: regrinding the mineral to adjust the pH value of the pulp to 8.0-10.0, adding 150-250g / t of collector and 50-100g / t of depressant to perform a roughing operation to obtain a roughing concentrate and a roughing tailing;

[0013] The rougher concentrate is subjected to two rounds of concentrating, with 30-50 g / t of inhibitor added during concentrating, to obtain a lepidolite flotation concentrate product with a lithium oxide grade of 1.8%-2.5% and a lithium oxide recovery rate greater than 92%. The rougher tailings product is subjected to two rounds of scavenging, with 100-200 g / t of collector added during scavenging, to obtain a flotation tailings product with a lithium grade of less than 0.1%.

[0014] Furthermore, the inhibitor is water glass or sodium hexametaphosphate; and the collector is coconut amine or dodecylamine.

[0015] The present method can achieve a separation index of a full-process lithium recovery rate greater than 85%.

[0016] Beneficial effects of the present invention:

[0017] According to the weak magnetic property of lepidolite, the invention combines modified water glass with coarse grinding to fully disperse the coarsely ground minerals, then adopts high background field strength magnetic separation. Only one stage of magnetic separation is used to achieve pre-enrichment of low-grade lepidolite ore, and removes 70%-80% of siliceous non-metallic mineral tailings such as muscovite, sericite, quartz and feldspar, which have surface properties similar to lepidolite. On the one hand, the problem of difficulty in flotation separation due to similar surface properties is reduced, and the lithium grade of the concentrate is significantly improved. On the other hand, the pre-enrichment process greatly improves the flotation feed grade, greatly reduces the flotation operation processing volume and the amount of reagents used, and significantly improves the lepidolite flotation operation recovery rate.

[0018] The present invention adopts a stage grinding-stage separation method, greatly increases the grinding fineness, reduces the over-crushing of lepidolite, reduces the lithium loss problem during desliming and flotation operations, reduces the water flow and foam entrainment of fine mud minerals during flotation, and improves the flotation concentrate grade. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 4 is a process flow chart of the separation method of the present invention. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] like Figure 1 As shown, a method for efficiently separating low-grade iron lithium mica ore comprises the following steps:

[0024] (1) A low-grade iron lithium mica ore with a lithium oxide grade of 0.1% in Jiangxi Province was crushed and coarsely ground to a particle size of -0.6 mm to obtain coarse ground minerals, wherein the particle size of the coarse ground minerals is -0.6 mm + 0.3 mm, accounting for 52%;

[0025] (2) The coarsely ground minerals were stirred and dispersed using modified water glass, and then a high-background magnetic separator with a background magnetic field strength of 4T was used for pre-enrichment by magnetic separation to obtain a lepidolite coarse concentrate with a concentrate yield of 20% and a lithium oxide grade of 0.56%. 80% of the tailings material with a lithium oxide grade of 0.025% was removed, and the recovery rate of the magnetic separation operation was 92.35%;

[0026] The amount of modified water glass is 600 g / t. The synthesis method of the modified water glass is as follows: water glass, citric acid and phosphoric acid are mixed in a mass ratio of 5:1:1, heated and stirred for reaction for 1 hour, and the reaction temperature is controlled at 80° C. After the reaction is completed, the modified water glass is obtained;

[0027] (3) regrinding and flotation purification of the lepidolite coarse concentrate, wherein the regrinding operation has a grinding fineness of -0.1 mm accounting for 40%, the pulp pH value is adjusted to 9.0, 150 g / t of a collector coconut amine and 50 g / t of an inhibitor sodium hexametaphosphate are added to perform a roughing operation to obtain a roughing concentrate and a roughing tailing;

[0028] The rougher concentrate was subjected to two rounds of cleaning, with 30 g / t of sodium hexametaphosphate as the inhibitor added each time, to obtain a flotation concentrate product with a lithium oxide grade of 1.8% and a flotation recovery rate of 92.65%. The rougher tailings were subjected to two rounds of scavenging, with 100 g / t of coconut amine as the collector added each time, to obtain a flotation tailings product with a lithium grade of 0.023%. This method can achieve a sorting index of 85.59% lithium recovery rate for the entire process.

[0029] Comparative Example 1

[0030] The same sample as Example 1 was taken, and a conventional on-site grinding-desliming flotation process was adopted. The ore was ground to a mineral particle size of less than -0.1 mm. The desliming operation removed fine mud with a lithium oxide grade of 0.085% and a yield of 12%. The pH value of the slurry was then adjusted to 9.0, and flotation was carried out using a one-rough, three-fine, and two-sweep process. The amount of collector coconut amine used in the roughing process was 250 g / t, and the amount of inhibitor sodium hexametaphosphate used was 100 g / t. The amount of inhibitor sodium hexametaphosphate used in each fine selection was 50 g / t. A full-process lithium concentrate product with a lithium oxide grade of 1.65% and a lithium recovery rate of 70.86% was obtained. The roughing tailings product was scavenged twice, and 100 g / t of collector coconut amine was added during each scavenging process to obtain a flotation tailings product with a lithium grade of 0.07%.

[0031] Through Example 1 and Comparative Example 1, by adopting the process flow of the present invention, the amount of collector used in flotation operation was reduced by 22.22%, the amount of inhibitor used was reduced by 56%, the lithium grade of flotation concentrate was increased by 0.15 percentage points, and the lithium recovery rate of the whole process was increased by 14.73 percentage points.

[0032] Comparative Example 2

[0033] (1) The same sample as in Example 1 was taken and coarsely ground to a particle size of -0.3 mm after crushing to obtain a coarsely ground mineral. For the coarsely ground sample, a 1.5T background magnetic field high gradient strong magnetic separation process was first used for separation to obtain a magnetic concentrate and a magnetic tailings. The magnetic concentrate yield was 12.56%, the lithium oxide grade was 0.52% of the lepidolite coarse concentrate, the magnetic tailings had a lithium oxide grade of 0.054%, and the magnetic separation operation recovery rate was 74.91%.

[0034] (2) The magnetic concentrate is regrinded and flotated for purification. The grinding fineness of the regrinding operation is -0.1mm, accounting for 40%. The product after regrinding is deslimed to remove the fine mud with a lithium oxide grade of 0.086% and a yield of 10.55%. Then the pH value of the ore pulp is adjusted to 9.0, and flotation is carried out using a one-roughing, three-fine, and two-sweeping process. The amount of collector coconut amine used in the roughing process is 250g / t, and the amount of inhibitor sodium hexametaphosphate used in the inhibitor sodium hexametaphosphate is 100g / t. The amount of inhibitor sodium hexametaphosphate used in each fine process is 50g / t. Finally, a full-process lithium concentrate product with a lithium oxide grade of 1.74% and a lithium oxide recovery rate of 63.67% is obtained. The roughing tailings product is scavenged twice, and 100g / t of collector coconut amine is added in each scavenging process to obtain a flotation tailing product with a lithium grade of 0.03%.

[0035] Through Example 1 and Comparative Example 2, by adopting the process flow of the present invention, the lithium recovery rate of the whole process increased by 21.92 percentage points.

[0036] Example 2

[0037] like Figure 1 As shown, a method for efficiently separating low-grade iron lithium mica ore comprises the following steps:

[0038] (1) A low-grade iron lithium mica ore with a lithium oxide grade of 0.3% in Hunan Province was crushed and coarsely ground to a particle size of -0.6 mm to obtain a coarsely ground mineral, wherein the particle size of the coarsely ground mineral is -0.6 mm + 0.3 mm, accounting for 55%;

[0039] (2) The coarsely ground minerals were stirred and dispersed using modified water glass, and then a high-background magnetic separator with a background magnetic field strength of 4T was used for pre-enrichment by magnetic separation to obtain a lepidolite coarse concentrate with a concentrate yield of 30% and a lithium oxide grade of 0.8%, and 70% of the tailings with a lithium oxide grade of 0.03% were removed. The recovery rate of the first-stage magnetic separation operation was 94.65%;

[0040] The amount of modified water glass is 1000 g / t. The synthesis method of the modified water glass is as follows: water glass, citric acid, and phosphoric acid are mixed in a mass ratio of 5:1:1, heated and stirred for reaction for 2 hours, and the reaction temperature is controlled at 100° C. After the reaction is completed, the modified water glass is obtained;

[0041] (3) regrinding and flotation purification of the lepidolite coarse concentrate, wherein the regrinding operation has a grinding fineness of -0.1 mm accounting for 30%, the pulp pH value is adjusted to 8.0, 250 g / t of a collector coconut amine and 80 g / t of an inhibitor sodium hexametaphosphate are added to perform a roughing operation to obtain a roughing concentrate and a roughing tailing;

[0042] The rougher concentrate was subjected to two rounds of cleaning, with 50 g / t of sodium hexametaphosphate as the inhibitor added each time, to obtain a flotation concentrate product with a lithium oxide grade of 2.2% and a flotation recovery rate of 93.83%. The rougher tailings were subjected to two rounds of scavenging, with 120 g / t of coconut amine as the collector added each time, to obtain a flotation tailings product with a lithium grade of 0.07%. This method can achieve a sorting index of a full-process lithium recovery rate of 88.81%.

[0043] Comparative Example 3

[0044] The same sample as Example 2 was taken, and a conventional on-site grinding-desliming flotation process was adopted. The ore was ground to a mineral particle size of less than -0.1 mm. The desliming operation removed fine mud with a lithium oxide grade of 0.28% and a yield of 15%. The pH value of the slurry was then adjusted to 9.0, and flotation was carried out using a one-rough, two-fine, two-sweep process. The amount of collector coconut amine used during roughing was 350 g / t, the amount of inhibitor sodium hexametaphosphate used was 120 g / t, and the amount of inhibitor sodium hexametaphosphate used during each fine selection was 80 g / t. A full-process lithium concentrate product with a lithium oxide grade of 1.85% and a lithium recovery rate of 74.32% was obtained. The roughing tailings product was scavenged twice, and 150 g / t of collector coconut amine was added during the scavenging to obtain a flotation tailings product with a lithium grade of 0.12%.

[0045] Through Example 2 and Comparative Example 3, by adopting the process flow of the present invention, the amount of collector used in flotation operation was reduced by 24.62%, the amount of inhibitor used was reduced by 35.71%, the lithium grade of flotation concentrate was increased by 0.35 percentage points, and the lithium recovery rate of the whole process was increased by 14.49 percentage points.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for efficiently separating low-grade iron lithium mica ore, characterized in that: The following steps are involved: (1) taking a low-grade iron lithium mica ore with a lithium oxide grade of 0.1%-0.3%, crushing and coarse-grinding it to a particle size of -0.6 mm to obtain a coarse-ground mineral, wherein the particle size of -0.6 mm+0.3 mm accounts for 50-55% of the coarse-ground mineral; (2) using modified water glass to stir and disperse the coarsely ground minerals, and then using a high background magnetic separator with a background magnetic field strength of 2-4T to perform a magnetic separation pre-enrichment to obtain a lepidolite coarse concentrate with a yield of 20%-30% and a lithium oxide grade of 0.5%-1.2%, and removing 70%-80% of the tailings material with a lithium oxide grade of less than 0.05%, and the lithium recovery rate of the magnetic separation operation is greater than 92%; (3) Regrinding the lepidolite coarse concentrate product to obtain regrinded minerals, and flotation-purifying the regrinded minerals to obtain lepidolite flotation concentrate products and flotation tailings products.

2. A method for efficiently separating low-grade iron lithium mica ore according to claim 1, characterized in that: In step (2), the synthesis method of modified water glass is as follows: water glass, citric acid and phosphoric acid are mixed in a mass ratio of 5:1:1, heated and stirred for reaction for 1-2 hours, and the reaction temperature is controlled to be 80-100°C. After the reaction is completed, modified water glass is obtained.

3. A method for efficiently separating low-grade iron lithium mica ore according to claim 1 or 2, characterized in that: In step (2), the amount of modified water glass is 500-1000g / t.

4. The method for efficiently separating low-grade iron lithium mica ore according to claim 1, wherein: In step (3), the grinding fineness of the regrinding operation is -0.1 mm, accounting for 30%-50%.

5. The method for efficiently separating low-grade iron lithium mica ore according to claim 1, wherein: In step (3), the flotation operation method is as follows: regrinding the mineral to adjust the pH value of the pulp to 8.0-10.0, adding 150-250g / t of collector and 50-100g / t of inhibitor to perform a roughing operation to obtain a roughing concentrate and a roughing tailing; The rougher concentrate is subjected to two rounds of concentrating, with 30-50 g / t of inhibitor added during concentrating, to obtain a lepidolite flotation concentrate product with a lithium oxide grade of 1.8%-2.5% and a lithium oxide recovery rate greater than 92%. The rougher tailings product is subjected to two rounds of scavenging, with 100-200 g / t of collector added during scavenging, to obtain a flotation tailings product with a lithium grade of less than 0.1%.

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