Grinding separation method for improving lepidolite concentrate flotation index

Abstract

The invention provides a grinding and selecting method for improving lepidolite concentrate flotation indexes, and belongs to the technical field of beneficiation. The grinding and selecting method comprises the steps that S1, lepidolite minerals are placed in a ceramic ball mill to be ground; s2, products obtained after ore grinding are graded, and the products are subjected to size mixing; s3, a flotation combined inhibitor and a collecting agent are added into the lepidolite flotation pulp for roughing, and rough concentrate and rough tailings are obtained; s4, the rough concentrate is subjected to third-time concentration, and concentrate is obtained; the coarse tailings are subjected to two-stage scavenging, and tailings are obtained; middlings obtained in the concentration process and the scavenging process are returned to the previous stage. According to the invention, a good flotation environment is created for medicament action by adopting a combined ore grinding method of precise proportioning of the ceramic ball mill and the ceramic balls; and meanwhile, the combined inhibitor is adopted, gangue minerals are effectively inhibited, flotation separation of lepidolite and gangue minerals is further achieved, and the lepidolite grading index is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ore dressing, and particularly relates to a grinding and separation method for improving the flotation index of lepidolite concentrate. Background Art

[0002] Lithium, as an important emerging strategic resource, is widely used in fields such as battery materials, aerospace, glass ceramics, and metallurgical chemistry. In recent years, with the proposal of the "dual carbon" goal, the new energy industry has become a hot spot for future development in China. As an important raw material for new energy batteries, the consumption of lithium shows a steadily increasing trend year by year. The lithium industry has become an important cornerstone for China to develop the new energy industry.

[0003] With the rise of the lithium industry, the development and utilization of lithium resources have become particularly important. China has rich lithium resources, accounting for 13.57% of the world's total. Most of them exist in salt lake brines. The lepidolite ore in Yichun, Jiangxi is one of the largest lithium ore resources in the world. As an important raw material for new energy batteries, the consumption of lithium shows a steadily increasing trend year by year, and the demand for lepidolite as an important raw material for lithium batteries has increased sharply. Since the gangue minerals in lepidolite are mainly quartz and feldspar, in the traditional steel ball medium grinding process, due to the large specific gravity of the steel balls, through-cracking is likely to occur. During the grinding process of lepidolite minerals, a large amount of fine mud minerals are very likely to be produced, which has an adverse impact on the subsequent flotation recovery operation. Therefore, the concentrate grade of lepidolite is generally about 3%, and the ore dressing recovery rate is generally below 70%.

[0004] At present, the beneficiation of lepidolite minerals is based on the research and development of flotation reagents or the improvement of processes. For example, CN 118179752 A discloses a method for enhancing the flotation of lepidolite ore based on high-entropy collectors. Under the condition of a relatively low dosage of high-entropy collectors, the enhanced flotation of lepidolite is achieved, the hydrophobicity difference between lepidolite and gangue minerals is increased, and the flotation foam structure and ore-carrying capacity are optimized. CN 115608520 A discloses a method for flotation of lepidolite without desliming. Utilizing the good flotability characteristics of lepidolite within a wide pH value range, a technological process for flotation of lepidolite without desliming is adopted. By using the flocculation flotation method, while improving the grade of lepidolite concentrate, the recovery rate of lithium is significantly increased. CN 109759224 B discloses a method for improving the grade of flotation concentrate of lepidolite ore. The floated product of lepidolite after grinding is directly fed into a hydrocyclone for desliming treatment. The classified sand products are added with reagents for one roughing and two scavenging operations. The roughing concentrate product is ground again in an Isa mill. After that, through one roughing and three cleaning operations, finally, lepidolite concentrate with a lithium grade of more than 3.30% and a lithium recovery rate of more than 80% is obtained. Although the Isa mill improves the flotation concentrate index to a certain extent, as a regrinding equipment, its processing capacity is limited, and no suitable ceramic ball medium ratio is formulated according to the properties of lepidolite ore. Therefore, there is an urgent need for a suitable grinding method and combined inhibition to disperse slime and inhibit gangue minerals, so as to improve the flotation concentrate index of lepidolite. Summary of the Invention

[0005] The present invention proposes a new grinding and beneficiation method for improving the flotation index of lepidolite concentrate. Aiming at the characteristics of easy slime formation during the grinding of lepidolite minerals, by introducing a ceramic ball medium grinding scheme, an accurate ceramic ball ratio for lepidolite grinding is formulated. Through the combined grinding method of a ceramic ball mill and an accurate ceramic ball ratio, the slime formation phenomenon of lepidolite minerals is effectively reduced, and the iron contamination in the grinding products is alleviated, thereby further realizing the flotation separation of lepidolite and gangue minerals, and the grinding process is simple. In the process without desliming, by using a combined inhibitor to inhibit gangue minerals, and finally, through the combined grinding-flotation beneficiation process, the flotation concentrate index of lepidolite is improved.

[0006] Specifically, the grinding and beneficiation method for improving the flotation index of lepidolite concentrate includes:

[0007] Step S1: Place the lepidolite minerals in a ceramic ball mill for grinding;

[0008] Step S2: Adjust the pulp of the product obtained after grinding to obtain lepidolite flotation pulp;

[0009] Step S3: Add a flotation combined inhibitor and a collector to the lepidolite flotation pulp for roughing to obtain rough concentrate and rough tailings;

[0010] Step S4: The rough concentrate is further subjected to three rounds of cleaning to obtain the concentrate; the rough tailings are further subjected to two rounds of scavenging to obtain the tailings; the middlings obtained during the cleaning process and the scavenging process are returned to the previous stage of re-separation. The middlings in the cleaning process and the scavenging process refer to the ores that have not entered the second and third rounds of cleaning or the second round of scavenging process.

[0011] Further, in step S1, the lining plate of the ceramic ball mill is a ceramic inner lining; the grinding balls are nano-ceramic balls, and the ratio of the grinding balls is 30 mm: 25 mm: 20 mm = 30%:40%:30% (by mass. Using different ratios of ceramic balls can reduce over-grinding during the grinding of lepidolite ore and improve the particle size distribution of the product); the percentage of the solid material mass contained in the pulp, i.e., the grinding concentration, is 65 - 70%.

[0012] Further, in step S2, the yield of -0.075 mm (i.e., passing through 200 meshes) accounts for 65 - 70%.

[0013] Further, in step S2, the pulp is adjusted to a pulp concentration of 35 - 40 wt%.

[0014] Further, in step S3, the combined flotation inhibitor is 10% sulfuric acid and sodium hexametaphosphate, and the dosages are 1600 - 2000 g / t and 300 - 400 g / t respectively; the flotation collector is dodecylamine, and the dosage is 500 - 600 g / t; the action time of the reagent is 3 min.

[0015] Further, in step S4, a combined inhibitor composed of 10% sulfuric acid and sodium hexametaphosphate is added during the first cleaning, and the dosages are 800 - 1000 g / t and 150 - 200 g / t respectively, and the action time of the reagent is 3 min; a collector composed of dodecylamine is added during the first scavenging, and the dosage is 250 - 300 g / t, and the action time of the reagent is 3 min.

[0016] Further, in step S4, no reagents are added during the second cleaning, the third cleaning, and the second scavenging.

[0017] The beneficial effects brought by the technical solution provided by the embodiments of the present invention at least include:

[0018] (1) Using a ceramic ball mill + ceramic balls greatly reduces the iron contamination phenomenon of traditional steel medium grinding, providing favorable conditions for the flotation operation. In addition to avoiding the iron contamination caused by traditional steel medium grinding, it also reduces over-grinding. By using a ceramic ball mixed ball diameter ratio, the average particle size of the grinding product is improved, and the average particle size is increased by up to 20%.

[0019] (2) During the flotation process, the synergistic effect of reagents mainly composed of sulfuric acid and sodium hexametaphosphate is adopted to achieve the selective inhibition of gangue minerals, creating conditions for improving the flotation indexes of lepidolite concentrate.

[0020] (3) The technological process of the present invention is simple, and it can realize flotation under the condition of not desliming. The grade of the flotation lepidolite concentrate reaches more than 4%, and the recovery rate is more than 80%, realizing the efficient recovery and utilization of lepidolite minerals. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a schematic diagram of the ceramic ball-milled ore product in Example 1 of the present invention, where (a) and (b) are the surface morphologies of the lepidolite milled products, Figure (c) represents the contact angle of the lepidolite milled products, and Figure (d) is the test result of the surface elements and their relative contents of the lepidolite milled products by SEM-EDS.

[0023] Figure 2 It is a schematic diagram of the steel ball-milled ore product in Comparative Example 1 of the present invention, where (a) and (b) are the surface morphologies of the lepidolite milled products, Figure (c) represents the contact angle of the lepidolite milled products, and Figure (d) is the test result of the surface elements and their relative contents of the lepidolite milled products by SEM-EDS.

[0024] Figure 3 It is a particle size distribution diagram of lepidolite minerals after milling with ceramic balls and steel balls in Example 2 and Comparative Example 2 of the present invention.

[0025] Figure 4 It is a schematic diagram of the lepidolite flotation process flow in Example 1 and Comparative Example 1 of the present invention.

[0026] Figure 5 It is a schematic diagram of the technological process of the present invention. Detailed Embodiments

[0027] The following will describe the technical solutions in the present invention with reference to the drawings.

[0028] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to give examples, illustrations or explanations. Any embodiment or design described as an "example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or designs. Rather, the use of the word "example" is intended to present concepts in a specific manner. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or either of the two can be selected.

[0029] In the embodiments of the present invention, "image" and "picture" can sometimes be used interchangeably. It should be noted that when the difference is not emphasized, the meanings they express are the same. "Of", "corresponding" and "correspondent" can sometimes be used interchangeably. It should be noted that when the difference is not emphasized, the meanings they express are the same.

[0030] In the embodiments of the present invention, sometimes a subscript such as W1 may be miswritten as a non-subscript form such as W1. When the difference is not emphasized, the meanings they express are the same.

[0031] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0032] Embodiment 1

[0033] This example uses pure lepidolite minerals from Pakistan (lepidolite purity exceeds 95%), and the main components are as follows:

[0034] Table 1 Chemical element analysis results of pure lepidolite minerals

[0035]

[0036] The specific operations are as follows:

[0037] Put the pure lepidolite minerals into a ceramic ball mill for grinding. The grinding medium used is nano-ceramic balls, and the specification ratio is 30 mm: 25 mm: 20 mm = 30%: 40%: 30%, and the mixed ball diameter is 25 mm. Weigh 2 g and put it into a 40 mL flotation cell, add 35 mL of deionized water, and adopt Figure 1 a simple one-stage roughing process. Add a pH adjuster (10% sulfuric acid) to adjust the pulp to pH = 3, stir for 3 min, add an inhibitor (the dosage of sodium hexametaphosphate is 50 mg / L), stir for 3 min, add a collector (the dosage of dodecylamine is 50 mg / L), stir for another 3 min, then inflate and start scraping foam, and the scraping foam time is 3 min. Filter, dry and weigh the collected foam products and the products in the cell respectively. And calculate the recovery rate, and the results are shown in Table 2.

[0038] Table 2 Flotation recovery rate of lepidolite under different grinding methods

[0039]

[0040] Comparative Example 1

[0041] The specific operating conditions are the same as those in Example 1, except that the mill used is a 2 L drum-type steel ball mill, the grinding medium used is steel balls, and the specification ratio is 30 mm: 25 mm: 20 mm = 30%:40%:30%, and the mixed ball diameter is 25 mm. The flotation results are shown in Table 2

[0042] From the flotation results in Table 2, it can be seen that under pure mineral conditions, ceramic ball grinding significantly improves the flotation recovery rate of lepidolite compared with steel ball grinding, and effectively reduces the output of fine-grained minerals. The SEM-EDS and contact angles of the ceramic ball and steel ball grinding products of pure lepidolite minerals are respectively as Figure 1 and Figure 2 shown. It can be seen that the iron medium pollution of the steel ball grinding product is relatively serious. The particle size screening results of the ceramic ball and steel ball grinding products of pure lepidolite minerals are as Figure 3 shown. By calculation, it can be obtained that ceramic ball grinding effectively improves the over-grinding phenomenon, and the average particle size of the grinding product is about 20% higher than that of the steel ball grinding product

[0043] Example 2

[0044] This example uses actual lepidolite minerals, and the main components are as follows

[0045] Table 3 Chemical element analysis results of actual lepidolite ore

[0046]

[0047] Flotation uses the Figure 2 shown process, and the specific operations are

[0048] Put 200 g of actual lepidolite ore into a ceramic ball mill for grinding. The grinding medium used is nano-ceramic balls, and the specification ratio is 30 mm: 25 mm: 20 mm = 30%:40%:30%, with a mixed ball diameter of 25 mm. Ensure that the proportion of -0.075 mm is approximately 65 - 70%; after pulp preparation, pour it into a 0.75 L flotation cell, then successively add the inhibitor and collector described in this case, stir for 3 min, start foaming, and foam for 3 min. Conduct one roughing (10% sulfuric acid and sodium hexametaphosphate, with dosages of 1600 - 2000 g / t and 300 - 400 g / t respectively, the addition amount of dodecylamine is 500 - 600 g / t, and the reagent action time is 3 min), one cleaning (the addition amounts of 10% sulfuric acid and sodium hexametaphosphate are 800 - 1000 g / t and 150 - 200 g / t respectively, and the reagent action time is 3 min), one scavenging (the addition amount of dodecylamine is 250 - 300 g / t, and the reagent action time is 3 min), two cleanings, three cleanings, and two scavengings are all blank flotations without adding reagents, and the middlings are returned according to the flotation process sequence. The concentrate product is scraped to the concentrate basin with the foam, the tailings product remains in the flotation cell, the concentrate and tailings are filtered, dried, and weighed separately, the grade of the concentrate is detected and the recovery rate is calculated, where K, X, and N represent the concentrate, tailings, and middlings products respectively. Figure 3 Table 3 shows the particle size screening results of lepidolite products under grinding with different grinding media. Table 4 shows the grade and recovery rate results of the actual ore flotation of lepidolite in Example 2 and Comparative Example 2.

[0049] Table 4 Recovery Rate of Lepidolite Actual Ore Flotation under Different Grinding Methods

[0050]

[0051] Comparative Example 2

[0052] The specific operating conditions are the same as those in Example 2, except that the mill used is a steel ball mill, the grinding medium used is steel balls, and the specification ratio is Φ30 mm:Φ25 mm:Φ20 mm = 30%:40%:30%, with a mixed ball diameter of 25 mm. The flotation results are shown in Table 4.

[0053] From the flotation results in Table 4, it can be seen that under actual ore conditions, ceramic ball grinding significantly improves the flotation index of lepidolite concentrate compared to steel ball grinding.

[0054] Comparative Example 3

[0055] The specific operating conditions are the same as those in Example 2, except that the inhibitor used is sodium hexametaphosphate with a dosage of 300 - 400 g / t, and the flotation results are shown in Table 5.

[0056] Table 5 Recovery Rate of Lepidolite Actual Ore Flotation under Different Inhibitor Conditions

[0057]

[0058] As can be seen from the flotation results in Table 5, under the actual ore conditions, the combined inhibitor of sulfuric acid and sodium hexametaphosphate significantly improved the flotation indexes of lepidolite concentrate compared with single inhibitors.

[0059] The above is only a specific implementation manner 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 can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims described.

Claims

1. A grinding and separation method for improving the flotation index of lepidolite concentrate, characterized in that, Including: Step S1: Place the lepidolite mineral in a ceramic ball mill for grinding; Step S2: Classify and adjust the pulp of the product obtained after grinding to obtain a lepidolite flotation pulp; Step S3: Add a flotation combined inhibitor and a collector to the lepidolite flotation pulp for rough selection to obtain rough concentrates and rough tailings; Step S4: Re-concentrate the rough concentrates three times to obtain concentrates; re-scavenge the rough tailings twice to obtain tailings; the middlings obtained during the concentration process and the scavenging process are returned to the previous stage for re-selection.

2. The method according to claim 1, characterized in that, In step S1, the ceramic ball mill liner is a ceramic inner lining; the grinding balls are nano-ceramic balls, and the proportion of the grinding balls is 30 mm: 25 mm: 20 mm = 30%:40%:30%; the grinding concentration is 65 - 70%.

3. The method according to claim 1, wherein In step S2, the grinding fineness is that -0.075 mm accounts for 65 - 70%.

4. The method according to claim 1, characterized in that In step S2, adjust the pulp to a flotation pulp concentration of 35 - 40 wt%.

5. The method according to claim 1, wherein In step S3, the flotation combined inhibitor is 10% sulfuric acid and sodium hexametaphosphate, and the dosages are 1600 - 2000 g / t and 300 - 400 g / t respectively; the flotation collector is dodecylamine, and the dosage is 500 - 600 g / t; the reagent action time is 3 min.

6. The method according to claim 1, wherein In step S4, a combined inhibitor composed of 10% sulfuric acid and sodium hexametaphosphate is added during the first concentration, and the dosages are 800 - 1000 g / t and 150 - 200 g / t respectively, and the reagent action time is 3 min; a collector composed of dodecylamine is added during the first scavenging, and the dosage is 250 - 300 g / t, and the reagent action time is 3 min.

7. The method according to claim 1, characterized in that, In step S4, no reagents are added during the second concentration, the third concentration, and the second scavenging.

Images