A method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation.

Abstract

This invention belongs to the field of mineral processing technology, specifically relating to a method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation. The method includes: first, coarsely crushing the low-grade natural flake graphite ore to obtain a coarse crushed product; then, finely crushing it using a crushing and screening machine to obtain a fine crushed product; grinding the fine crushed product using a sample preparation pulverizer to obtain raw flake graphite ore; mixing the obtained raw flake graphite ore with water to prepare a slurry; then performing ultrasonic pretreatment; adding a pH adjuster to adjust the slurry pH to 6-9; then adding a cationic activator at a dosage of 80-160 g / t; followed by the sequential addition of an inhibitor, collector, and frother; and finally, performing aeration and frothing to obtain a concentrate by flotation. This method can increase the fixed carbon content of low-grade natural flake graphite ore to over 75% through a single roughing process.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cation activation. Background Technology

[0002] Graphite, as a strategic resource, is widely used in new energy, electronics, medical, metallurgical, and aerospace fields due to its unique structure and characteristics such as thermal conductivity, electrical conductivity, lubrication, high temperature resistance, and chemical stability. It has become an indispensable non-metallic material in the development of modern industry and high-tech industries, and occupies an increasingly important position in global economic development.

[0003] Natural graphite ore is mainly divided into flake graphite and microcrystalline graphite. Flake graphite is mainly used as a raw material for advanced technologies such as batteries and atomic energy. With the continuous development of science and technology, high-grade flake graphite ore is becoming increasingly scarce. At the same time, various countries have listed flake graphite ore as a strategic resource and restricted its export. Therefore, the development and utilization of low-grade flake graphite ore is particularly important.

[0004] Currently, flotation is the primary purification step for flake graphite. In low-grade graphite ore, impurities are often embedded with the graphite. Researchers often employ multiple stages of grinding to promote impurity liberation. However, multiple grinding stages reduce the size of large-sized flake graphite, hindering the development and utilization of downstream products. Simultaneously, due to the low grade and high impurity content, the fixed carbon content of the concentrate from the roughing process is low. Therefore, subsequent flotation purification often involves multiple cleaning stages. However, these multiple cleaning stages result in a long experimental process, leading to low flotation efficiency and the excessive use of flotation reagents, which in turn causes environmental pollution and other problems. Therefore, exploring a process to address the issues of protecting large-sized flakes, reducing inclusions, and overcoming the problems of multiple cleaning stages and long flotation processes is crucial.

[0005] Ultrasonic technology, which emerged in the 20th century, is a highly effective auxiliary enhancement method and has seen some development in ore processing in recent years. Ultrasound in aqueous solutions can induce thermal, mechanical, and cavitation effects, among others. Before flotation, ultrasonic technology can effectively improve the true display state of ore particles. For example, ultrasound can remove impurities from the ore surface, exposing new surfaces for adsorption with flotation reagents, reducing impurity inclusions during flotation, and promoting the liberation of impurities from the target minerals.

[0006] CN115025876A describes a beneficiation process for graphite ore. The process involves coarsely crushing the graphite ore using a jaw crusher and finely crushing it using a double-roll crusher, followed by screening. The oversize material is returned to the double-roll crusher, while the undersize material is dried in an oven to constant weight to obtain rough ore. The process flow is as follows: S2: The rough ore undergoes coarse grinding, rough separation, and scavenging; S3: The rough concentrate obtained from the rough separation in step S2 undergoes four grinding and eight separation processes; S4: The middlings are centrally refractory and re-spared, and returned in batches. This method uses multiple crushing and grinding processes to liberate impurities, which can easily damage large-sized flake graphite. Furthermore, the method employs one roughing and eight cleaning processes, resulting in a long flotation process, low efficiency, and repeated use of reagents, causing environmental impact.

[0007] Yang Jianwen's article, "Experimental Study on Beneficiation of Low-Grained Fine-Grained Flake Graphite in Hunan," published in *Mining Machinery*, focuses on a low-grade flake graphite with a fixed carbon content of 4.56%. Using sodium hexametaphosphate and water glass as dispersants and inhibitors, kerosene as a collector, and No. 2 oil as a frother, the fixed carbon content was increased to 21.06% after one roughing process. Finally, through a closed-circuit test of one roughing and five cleaning processes, a graphite concentrate with a fixed carbon content of 92.53% was obtained. Zhang Tao et al.'s article, "Experimental Study on Beneficiation of Low-Grained Large-Grained Flake Graphite Deposit in Inner Mongolia," published in *Comprehensive Utilization of Mineral Resources*, focuses on a beneficiation test of a large-grained flake graphite deposit with a fixed carbon content of 3.55% in Inner Mongolia Autonomous Region, using coal... Oil was used as the collector and No. 2 oil as the frother for a first roughing process, increasing the fixed carbon content of the roughing concentrate to 18.25%. Finally, under the roughing conditions, a graphite concentrate with a fixed carbon content of 95.44% was obtained through a two-stage roughing process, a one-stage scavenging process, a six-stage regrinding process, and a seven-stage cleaning process. Wang Jinling et al. published an article in "China Mining" entitled "Experimental Study on Beneficiation of a Low-Grade Large-Flake Graphite Mine". The article mainly studied the beneficiation of a low-grade large-flake graphite mine with a fixed carbon content of 2.05%. Through a first roughing process, the fixed carbon content was increased to 33.67%. Finally, through a closed-circuit process of one stage of rod milling, one stage of ball milling of the rough concentrate, five stages of stirred milling, and nine-stage cleaning, a graphite concentrate with a fixed carbon content of 95% was obtained.

[0008] All three articles mentioned above used low-grade flake graphite for flotation experiments. A single roughing process yielded a rough concentrate with a maximum fixed carbon content of 33.67%. Due to the low fixed carbon content of the rough concentrate, multiple cleaning and grinding processes were used in the subsequent flotation. Although a graphite concentrate with a purity of about 95% was eventually obtained, such a long and complex experimental process not only increased the amount of reagents used, thus increasing the environmental impact, but also reduced production efficiency. In addition, multiple grinding processes damaged large-sized flake graphite. Summary of the Invention

[0009] To address the problems of insufficient liberation of graphite ore from impurities in conventional flotation processes for low-grade natural flake graphite, leading to severe inclusions during flotation, and the numerous cleaning cycles, long flotation processes, and severe damage to large-sized flake graphite caused by multi-stage grinding, this invention provides a method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cation activation. This method aims to both ensure sufficient liberation of graphite ore from impurities and reduce inclusions, while simultaneously increasing the fixed carbon content of the concentrate in the roughing process, thereby reducing the number of cleaning cycles and shortening the flotation process. Furthermore, the ultrasonic pretreatment employed in this invention reduces the need for multi-stage grinding, protecting large-sized flake graphite. To achieve the above objectives of this invention, the following technical solution is adopted:

[0010] This invention discloses a method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation, comprising the following steps:

[0011] Step 1

[0012] Flake graphite ore is crushed and ground until the grinding particle size of -100 mesh accounts for more than 90% to obtain raw flake graphite ore;

[0013] Step Two

[0014] Flake graphite ore is mixed with water at a slurry concentration of 8 wt.% to 25 wt.% to obtain a slurry; then, it is ultrasonically pretreated for at least 10 minutes to obtain an ultrasonically pretreated slurry; during ultrasonic pretreatment, the ultrasonic frequency is controlled at 18-22 kHz.

[0015] Step 3

[0016] The pH of the ultrasonically pretreated slurry was adjusted to 6-9; and a cationic activator was added at a ratio of 80-160 g / t and stirred evenly for at least 1 minute to obtain the cationic activated slurry; the cationic activator was selected from at least one of NaCl and KCl.

[0017] Step Four

[0018] Inhibitors, collectors, and frothers are added to the cationic activated slurry for roughing to obtain rough concentrate and rough tailings. Inhibitors are added at a dosage of 600-1200 g / t, collectors at a dosage of 280-400 g / t, and frothers at a dosage of 160-280 g / t.

[0019] As a preferred embodiment, the present invention provides a method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation.

[0020] Flake graphite ore with a fixed carbon content of 2.68% to 8.48% is coarsely crushed to 8-35mm or more to obtain coarse crushed product. Then, it is finely crushed to 0.1-3mm or more to obtain fine crushed product.

[0021] The obtained finely crushed product is ground in a pulverizer for 2-5 minutes, with the grinding particle size of -100 mesh accounting for more than 90%, to obtain flake graphite raw ore.

[0022] As a preferred embodiment, the present invention provides a method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cation activation, wherein the obtained flake graphite ore is mixed with water at a slurry concentration of 8% to 25% and stirred for 3 to 5 minutes to obtain a slurry.

[0023] The resulting slurry was subjected to ultrasonic pretreatment for 15–40 minutes.

[0024] As a preferred embodiment, the present invention provides a method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation.

[0025] The ultrasonically pretreated slurry is transferred to a flotation cell and stirred for 1–3 minutes. Then, a pH adjuster is added to adjust the pH of the slurry to 6–9, preferably 7.5–8.5, and stirred for 2–5 minutes.

[0026] As a preferred embodiment, the present invention provides a method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation.

[0027] Add 80–160 g / t of cationic activator to the pH-adjusted slurry and stir for 1–3 min; then add 600–1200 g / t of inhibitor and stir for 2–5 min; next, add 280–400 g / t of collector and stir for 2–5 min; after adding the collector and stirring, add 160–280 g / t of frother. After stirring for 1–3 min, turn on the aeration switch and then scrape the foam for 4–9 min. Filter and dry the scraped foam to obtain flake graphite concentrate, and the remainder is tailings. Cationic activator is added to the pH-adjusted slurry at a ratio of 80-160g cationic activator per ton of slurry, and stirred for 1-3 minutes. Then, inhibitor is added at a ratio of 600-1200g inhibitor per ton of slurry, and stirred for 2-5 minutes. Next, collector is added at a ratio of 280-400g collector per ton of slurry, and stirred for 2-5 minutes. After adding collector and stirring, frother is added at a ratio of 160-280g frother per ton of slurry. After stirring for 1-3 minutes, the aeration switch is turned on, and then the foam is scraped for 4-9 minutes. The scraped foam is filtered and dried to obtain flake graphite concentrate, and the remainder is tailings.

[0028] As a further preferred option, a cationic activator is added to the pH-adjusted slurry at a dosage of 105–145 g / t. As an even more preferred option, a cationic activator is added to the pH-adjusted slurry at a dosage of 109–125 g / t.

[0029] As a further preferred option, the inhibitor is added at a dosage of 600–1000 g / t, and even more preferably at a dosage of 800–1000 g / t. In this invention, if the dosage of the inhibitor is too low, such as 500 g / t, it will result in a low fixed carbon content in the product and a low graphite recovery rate.

[0030] As a further preferred option, the collector is added at a dosage of 285–360 g / t. As an even more preferred option, the collector is added at a dosage of 315–355 g / t. In this invention, excessive use of the collector will not only fail to increase the graphite recovery rate but will also reduce the fixed carbon content.

[0031] As a further preferred option, a foaming agent is added at a dosage of 160–260 g / t. For an even more preferred option, an inhibitor is added at a dosage of 175–265 g / t. In this invention, if the dosage of the foaming agent is too low, such as 140 g / t, it will also result in a low fixed carbon content in the product and a low graphite recovery rate.

[0032] The crusher used in this invention includes a jaw crusher, and the crushing and screening machine is a roller crushing and screening machine.

[0033] The water used in this invention includes deionized water.

[0034] The power of ultrasound is 60-150W.

[0035] The flotation machines used include the XFG5-35 hanging tank flotation machine.

[0036] During the flotation process, the flotation machine impeller is used for stirring, with a rotation speed of 1000-1500 r / min.

[0037] The pH adjusters used were HCl and NaOH.

[0038] The inhibitors used are one or more of water glass, CaO, and sodium carboxymethyl cellulose.

[0039] The collector used is either kerosene or diesel oil.

[0040] The foaming agent used is one of terpineol, methyl isobutyl alcohol, or 2-octanol.

[0041] After turning on the intake switch, the intake volume is 30-60 L / h.

[0042] The fixed carbon content in the graphite concentrate obtained from the first roughing process can reach 75-80%, and the graphite recovery rate is greater than or equal to 89%. After optimization, the graphite recovery rate is greater than or equal to 91%.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] This invention employs ultrasonic equipment to pretreat natural flake graphite ore using ultrasonic technology, which promotes the dissociation of graphite ore from impurities and increases the fixed carbon content in the flotation concentrate during the roughing process. Simultaneously, the invention combines this with the activation treatment of graphite ore using a cationic activator, which enhances the hydrophobicity of the graphite ore, facilitating the separation of graphite ore from impurities and increasing its fixed carbon content. This reduces the number of flotation cleaning cycles and thus lowers the usage of various flotation reagents. Attached Figure Description

[0045] Figure 1 A flowchart of a specific embodiment of the present invention. Detailed Implementation

[0046] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0047] A method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation includes the following steps:

[0048] (1) The natural flake graphite ore with a fixed carbon content of 2.68% to 8.48% is coarsely crushed to 8 to 35 mm with more than 80% of the content to obtain coarse crushed product. Then, it is finely crushed to 0.1 to 3 mm with more than 80% of the content to obtain fine crushed product.

[0049] (2) Grind the finely crushed product using a sample grinding mill for 2-5 minutes, with the grinding particle size of -100 mesh accounting for more than 90%, to obtain flake graphite raw ore;

[0050] (3) Mix the flake graphite ore obtained in step (2) with water at a ratio of 8% to 25% of the slurry concentration, and stir for 3 to 5 minutes to obtain the slurry;

[0051] (4) The slurry obtained in step (3) is subjected to ultrasonic pretreatment for 15 to 40 minutes.

[0052] (5) Transfer the ultrasonically pretreated slurry to the flotation cell and stir for 1 to 3 minutes;

[0053] (6) Add pH adjuster to the slurry obtained in step (5) to adjust the pH of the slurry to 6-9 and stir for 2-5 minutes;

[0054] (7) Add cationic activator to the above-adjusted pH slurry at a dosage of 80-160 g / t and stir for 1-3 min;

[0055] (8) Add inhibitor to the above-mentioned slurry containing cationic activator at a dosage of 600-1200 g / t, and stir for 2-5 min;

[0056] (9) Add the collector to the above-mentioned slurry with added inhibitor at a dosage of 280-400 g / t and stir for 2-5 min;

[0057] (10) Add frother to the above-mentioned slurry containing collector at a dosage of 160-280 g / t. After stirring for 1-3 minutes, turn on the aeration switch and then scrape the foam for 4-9 minutes. Filter and dry the scraped foam to obtain flake graphite concentrate. The rest is tailings.

[0058] In one specific embodiment, the crusher in step (1) is a jaw crusher and the crushing and screening machine is a roller crushing and screening machine.

[0059] In one specific embodiment, the aqueous solution used in step (3) is deionized water.

[0060] In one specific embodiment, the ultrasonic equipment used in step (4) is an intelligent numerical control ultrasonic generator with a power setting of 60-150W, and ultrasonic treatment is performed at room temperature.

[0061] In one specific embodiment, the flotation machine used in step (5) is an XFG5-35 hanging flotation machine.

[0062] In one specific embodiment, the stirring process in steps (5) to (10) is carried out by stirring with a flotation machine impeller at a speed of 1000 to 1500 r / min.

[0063] In one specific embodiment, the pH adjuster used in step (6) is HCl and NaOH.

[0064] In one specific embodiment, the cationic activator used in step (7) is either NaCl or KCl.

[0065] In one specific embodiment, the inhibitor used in step (8) is one or more of water glass, CaO, and sodium carboxymethyl cellulose, and the agent is selected according to the type of impurities in different minerals.

[0066] In one specific embodiment, the collector used in step (9) is either kerosene or diesel oil.

[0067] In one specific embodiment, the foaming agent used in step (10) is one of terpineol, methyl isobutyl alcohol, and octanol.

[0068] In one specific implementation, the air intake volume in step (10) is 30-60 L / h.

[0069] In one specific embodiment, the fixed carbon content of the graphite concentrate obtained in step (10) can reach 78.93%.

[0070] The specific embodiments of the present invention will be further described below with reference to examples, but the present invention is not limited to the scope of the embodiments described herein.

[0071] Example 1

[0072] The XRD results of the natural flake graphite ore produced in the mining area of ​​Inner Mongolia Autonomous Region show that the impurities are mainly mica and quartz, and its composition is shown in Table 1.

[0073] Table 1. Composition of Natural Flake Graphite from a Mining Area in Inner Mongolia Autonomous Region

[0074]

[0075] The natural flake graphite ore is first crushed to 8-35mm or more by an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more by an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 3 minutes by a sample preparation pulverizer to a grinding particle size of -100 mesh or more to obtain flake graphite ore.

[0076] The obtained flake graphite ore was mixed with water at a slurry concentration of 20% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 100W and a frequency of 20KHz for 30 minutes.

[0077] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1200 r / min for 3 min. Then, HCl is added to adjust the pH of the slurry to 8 and stirring is continued for 3 min. Next, cationic activator NaCl is added at a dosage of 110 g / t and stirred for 1 min.

[0078] Add water glass inhibitor at a dosage of 800 g / t to the slurry containing the cationic activator, stir for 3 min, then add kerosene collector at a dosage of 320 g / t and continue stirring for 3 min. Then add terpineol frother at a dosage of 180 g / t. After stirring for 3 min, turn on the aeration switch and set the air intake rate to 40 L / h. Then perform skimming for 7 min. Filter the skimmed foam and dry it at 105℃ to obtain flake graphite concentrate.

[0079] The flotation process was carried out at room temperature for natural flake graphite ore. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 76.53% and recovery rate of 92.14%.

[0080] The graphite concentrate obtained from the roughing process was further refined using 400 g / t of water glass as an inhibitor, 160 g / t of kerosene as a collector, and 90 g / t of terpineol as a frother. After three refinements, the fixed carbon content in the graphite concentrate increased to 94.85%.

[0081] Example 2

[0082] The XRD test results of the natural flake graphite ore produced in a mining area in Henan Province showed that the main impurities were mica, quartz, feldspar and pyrite, and its composition is shown in Table 2.

[0083] Table 2. Composition of Natural Flake Graphite from a Mining Area in Henan Province

[0084]

[0085] The natural flake graphite ore is first crushed to 8-35mm or more by an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more by an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 5 minutes by a sample preparation pulverizer to a grinding particle size of -100 mesh or more to obtain flake graphite raw ore.

[0086] The obtained flake graphite ore was mixed with water at a slurry concentration of 18% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 150W and a frequency of 21KHz for 30 minutes.

[0087] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 min. Then, HCl is added to adjust the pH of the slurry to 8 and stirring is continued for 3 min. Next, cationic activator KCl is added at a dosage of 120 g / t and stirred for 1 min.

[0088] Add 600 g / t water glass and 400 g / t calcium oxide inhibitor to the slurry containing the cationic activator. After stirring for 3 minutes, add diesel collector at a dosage of 350 g / t and continue stirring for 3 minutes. Then add methyl isobutyl methanol frother at a dosage of 260 g / t. After stirring for 3 minutes, turn on the air supply switch and set the air intake rate to 50 L / h. Then perform foam scraping for 6 minutes. Filter the scraped foam and dry it at 105℃ to obtain flake graphite concentrate.

[0089] In the flotation process, roughing flotation of natural flake graphite ore was carried out under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 78.93% and recovery rate of 91.27%.

[0090] The graphite concentrate obtained from the roughing process was further refined using 300 g / t water glass and 200 g / t calcium oxide as inhibitors, 180 g / t diesel oil as collector, and 130 g / t methyl isobutyl methanol as frother. After three refinements, the fixed carbon content in the graphite concentrate increased to 95.37%.

[0091] Example 3

[0092] The XRD test results of the natural flake graphite ore produced in a mining area of ​​Yunnan Province showed that the main impurities were mica, quartz, feldspar and pyrite, and its composition is shown in Table 3.

[0093] Table 3. Composition of Natural Flake Graphite from a Mining Area in Yunnan Province

[0094]

[0095]

[0096] The natural flake graphite ore is first crushed to 8-35mm or more by an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more by an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 3 minutes by a sample preparation pulverizer to a grinding particle size of -100 mesh or more to obtain flake graphite ore.

[0097] The obtained flake graphite ore was mixed with water at a slurry concentration of 25% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 80W and a frequency of 20KHz for 30 minutes.

[0098] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1500 r / min for 3 min. Then, NaOH is added to adjust the pH of the slurry to 9, and stirring is continued for 3 min. Next, cationic activator NaCl is added at a dosage of 140 g / t and stirred for 1 min.

[0099] Add 650 g / t water glass and 500 g / t sodium carboxymethyl cellulose inhibitor to the slurry containing the cationic activator. After stirring for 3 minutes, add 300 g / t diesel collector and continue stirring for 3 minutes. Then add 200 g / t octanol frother. After stirring for 3 minutes, turn on the air supply switch and set the air intake rate to 45 L / h. Then perform frothing for 7 minutes. Filter the froth and dry it at 105°C to obtain flake graphite concentrate.

[0100] In the flotation process, natural flake graphite ore was flotated under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 74.93% and recovery rate of 91.21%.

[0101] The graphite concentrate obtained from the roughing process was further refined using 320 g / t water glass and 250 g / t sodium carboxymethyl cellulose inhibitor, 150 g / t diesel fuel collector, and 100 g / t octanol frother. After four refinements, the fixed carbon content in the graphite concentrate increased to 95.13%.

[0102] Example 4

[0103] The XRD test results of the natural flake graphite ore produced in a mining area in Henan Province show that the main impurities are mica, quartz and feldspar, and its composition is shown in Table 4.

[0104] Table 4. Composition of Natural Flake Graphite from a Mining Area in Henan Province

[0105]

[0106] The natural flake graphite ore is first crushed to 8-35mm or more by an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more by an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 3 minutes by a sample preparation pulverizer to a grinding particle size of -100 mesh or more to obtain flake graphite ore.

[0107] The obtained flake graphite ore was mixed with water at a slurry concentration of 23% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 60W and a frequency of 22KHz for 30 minutes.

[0108] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 min. Then, HCl is added to adjust the pH of the slurry to 7 and stirring is continued for 3 min. Next, cationic activator KCl is added at a dosage of 130 g / t and stirred for 1 min.

[0109] Add 400 g / t water glass and 480 g / t sodium carboxymethyl cellulose inhibitor to the slurry containing the cationic activator. After stirring for 3 minutes, add 290 g / t kerosene collector and continue stirring for 3 minutes. Then add 160 g / t frother terpineol. After stirring for 3 minutes, turn on the aeration switch and set the air intake to 60 L / h. Then perform foam scraping for 8 minutes. Filter the scraped foam and dry it at 105°C to obtain flake graphite concentrate.

[0110] In the flotation process, natural flake graphite ore was flotated under ambient temperature conditions. The flotation product obtained through continuous scale-up testing had the following specifications: fixed carbon content of 75.14% and recovery rate of 89.37%.

[0111] The graphite concentrate obtained from the roughing process was further refined using 200 g / t water glass and 240 g / t sodium carboxymethyl cellulose inhibitor, 150 g / t kerosene collector, and 800 g / t terpineol frother. After three refinements, the fixed carbon content in the graphite concentrate increased to 94.62%.

[0112] Comparative Example 1

[0113] The other conditions are the same as the coarse selection process in Example 2, except that ultrasonic treatment is not performed; that is:

[0114] The obtained flake graphite ore was mixed with water at a pulp concentration of 18% and stirred for 3 minutes to obtain a pulp. The pulp was then transferred to the flotation cell of an XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 minutes. HCl was then added to adjust the pH of the pulp to 8, and stirring was continued for 3 minutes. Next, cationic activator KCl was added at a dosage of 120 g / t and stirred for 1 minute.

[0115] Add 600 g / t water glass and 400 g / t calcium oxide inhibitor to the slurry containing the cationic activator. After stirring for 3 minutes, add diesel collector at a dosage of 350 g / t and continue stirring for 3 minutes. Then add methyl isobutyl methanol frother at a dosage of 260 g / t. After stirring for 3 minutes, turn on the air supply switch and set the air intake rate to 40 L / h. Then perform frothing for 6 minutes. Filter the froth and dry it at 105℃ to obtain flake graphite concentrate.

[0116] In the flotation process, natural flake graphite ore was flotated under ambient temperature conditions. The flotation product obtained through continuous scale-up testing had the following specifications: fixed carbon content of 72.33% and recovery rate of 81.52%.

[0117] Comparative Example 2

[0118] The other conditions are the same as the roughing process in Example 2, except that no cationic activator is added; that is:

[0119] The obtained flake graphite ore was mixed with water at a slurry concentration of 18% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 150W and a frequency of 21KHz for 30 minutes.

[0120] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 min. Then, HCl is added to adjust the pH of the slurry to 8 and stirring is continued for 3 min.

[0121] Add 600 g / t water glass and 400 g / t calcium oxide inhibitor to the above slurry, stir for 3 min, then add 350 g / t diesel collector and continue stirring for 3 min. Then add 260 g / t frother methyl isobutyl methanol. After stirring for 3 min, turn on the air supply switch and set the air intake rate to 40 L / h. Then perform frothing for 6 min. Filter the froth and dry it at 105℃ to obtain flake graphite concentrate.

[0122] The flotation process was carried out at room temperature for natural flake graphite ore. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 58.70% and recovery rate of 87.26%.

[0123] Comparative Example 3

[0124] Other conditions are the same as the roughing process in Example 2, except that: ultrasonic pretreatment is not performed, and no cationic activator is added; that is:

[0125] The obtained flake graphite ore was mixed with water at a pulp concentration of 18% and stirred for 3 minutes to obtain a pulp. The pulp was then transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 minutes. HCl was then added to adjust the pH of the pulp to 8, and stirring was continued for 3 minutes.

[0126] Add 600 g / t water glass and 400 g / t calcium oxide inhibitor to the above slurry, stir for 3 min, then add 350 g / t diesel collector and continue stirring for 3 min. Then add 260 g / t frother methyl isobutyl methanol. After stirring for 3 min, turn on the air supply switch and set the air intake rate to 40 L / h. Then perform frothing for 6 min. Filter the froth and dry it at 105℃ to obtain flake graphite concentrate.

[0127] In the flotation process, natural flake graphite ore was flotated under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 47.39% and recovery rate of 68.71%.

[0128] Comparative Example 4

[0129] The other conditions are the same as the rough selection process in Example 2, except that the inhibitor dosage range is not within the protection range of 600-1200 g / t of this invention.

[0130] The obtained flake graphite ore was mixed with water at a slurry concentration of 18% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 150W and a frequency of 21KHz for 30 minutes.

[0131] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 min. Then, HCl is added to adjust the pH of the slurry to 8 and stirring is continued for 3 min. Next, cationic activator KCl is added at a dosage of 120 g / t and stirred for 1 min.

[0132] Add 300 g / t water glass and 200 g / t calcium oxide inhibitor to the slurry containing the cationic activator. After stirring for 3 minutes, add diesel collector at a dosage of 350 g / t and continue stirring for 3 minutes. Then add methyl isobutyl methanol frother at a dosage of 260 g / t. After stirring for 3 minutes, turn on the air supply switch and set the air intake rate to 40 L / h. Then perform foam scraping for 6 minutes. Filter the scraped foam and dry it at 105℃ to obtain flake graphite concentrate.

[0133] In the flotation process, natural flake graphite ore was flotated under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 38.27% and recovery rate of 53.21%.

[0134] Comparative Example 5

[0135] The other conditions are the same as the roughing process in Example 2, except that the amount of collector used is outside the protection range of 280-400 g / t of this invention.

[0136] The obtained flake graphite ore was mixed with water at a slurry concentration of 18% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 150W and a frequency of 21KHz for 30 minutes.

[0137] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 min. Then, HCl is added to adjust the pH of the slurry to 8 and stirring is continued for 3 min. Next, cationic activator KCl is added at a dosage of 120 g / t and stirred for 1 min.

[0138] Add 600 g / t water glass and 400 g / t calcium oxide inhibitor to the slurry containing the cationic activator. After stirring for 3 minutes, add 500 g / t diesel collector and continue stirring for 3 minutes. Then add 260 g / t frother methyl isobutyl methanol. After stirring for 3 minutes, turn on the air supply switch and set the air intake rate to 40 L / h. Then perform frothing for 6 minutes. Filter the froth and dry it at 105°C to obtain flake graphite concentrate.

[0139] In the flotation process, natural flake graphite ore was flotated under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 49.37% and recovery rate of 56.87%.

[0140] Comparative Example 6

[0141] Other conditions and the roughing process in Example 2 are the same, except that the foaming agent dosage range is not within the protection scope of this invention (160-280 g / t).

[0142] The obtained flake graphite ore was mixed with water at a slurry concentration of 18% and stirred for 3 minutes to obtain a slurry. Then, it was ultrasonically pretreated using an intelligent numerical control ultrasonic generator at a power of 150W and a frequency of 21KHz for 30 minutes.

[0143] After ultrasonic pretreatment, the slurry is transferred to the flotation cell of the XFG5-35 hanging flotation machine and stirred at 1400 r / min for 3 min. Then, HCl is added to adjust the pH of the slurry to 8 and stirring is continued for 3 min. Next, cationic activator KCl is added at a dosage of 120 g / t and stirred for 1 min.

[0144] Add 600 g / t water glass and 400 g / t calcium oxide inhibitor to the slurry containing the cationic activator. After stirring for 3 minutes, add diesel collector at a dosage of 350 g / t and continue stirring for 3 minutes. Then add methyl isobutyl methanol frother at a dosage of 140 g / t. After stirring for 3 minutes, turn on the air supply switch and set the air intake rate to 40 L / h. Then perform foam scraping for 6 minutes. Filter the scraped foam and dry it at 105℃ to obtain flake graphite concentrate.

[0145] In the flotation process, natural flake graphite ore was flotated under ambient temperature conditions. The flotation product obtained through continuous scale-up testing had the following specifications: fixed carbon content of 61.59% and recovery rate of 42.98%.

Claims

1. A method for purifying low-grade flake graphite ore through ultrasonic pretreatment combined with cationic activation, characterized in that, Includes the following steps: Step 1 Flake graphite ore is crushed and ground until the grinding particle size of -100 mesh accounts for more than 90% to obtain raw flake graphite ore; Step Two Flake graphite ore and water are mixed evenly at a slurry concentration of 8wt.% to 25wt.% to obtain a slurry; then ultrasonic pretreatment is performed for at least 10 minutes to obtain an ultrasonically pretreated slurry; during ultrasonic pretreatment, the ultrasonic frequency is controlled at 18-22KHz. Step 3 The pH of the ultrasonically pretreated slurry was adjusted to 6-9; and a cationic activator was added at a ratio of 80-160 g / t and stirred evenly for at least 1 minute to obtain the cationic activated slurry; the cationic activator was selected from at least one of NaCl and KCl. Step Four Inhibitors, collectors, and frothers are added to the cationic activated slurry for roughing to obtain rough concentrate and rough tailings. Inhibitors are added at a dosage of 600-1200 g / t, collectors at a dosage of 280-400 g / t, and frothers at a dosage of 160-280 g / t.

2. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 1, characterized in that: Flake graphite ore with a fixed carbon content of 2.68% to 8.48% is coarsely crushed to 8-35mm or more to obtain coarse crushed product. Then, it is finely crushed to 0.1-3mm or more to obtain fine crushed product. The obtained finely crushed product is ground in a pulverizer for 2-5 minutes, with the grinding particle size of -100 mesh accounting for more than 90%, to obtain flake graphite raw ore.

3. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 1, characterized in that: The obtained flake graphite ore is mixed with water at a slurry concentration of 8wt.% to 25wt.% and stirred for 3 to 5 minutes to obtain a slurry. The resulting slurry was subjected to ultrasonic pretreatment for 15–40 minutes.

4. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 3, characterized in that: The ultrasonically pretreated slurry is transferred to a flotation cell and stirred for 1–3 minutes; then a pH adjuster is added to adjust the pH of the slurry to 6–9 and stirred for 2–5 minutes.

5. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 4, characterized in that: Add 80–160 g / t of cationic activator to the pH-adjusted slurry and stir for 1–3 min; then add 600–1200 g / t of inhibitor and stir for 2–5 min; next, add 280–400 g / t of collector and stir for 2–5 min; after adding the collector and stirring, add 160–280 g / t of frother. After stirring for 1–3 min, turn on the aeration switch and then scrape the foam for 4–9 min. Filter and dry the scraped foam to obtain flake graphite concentrate, and the remainder is tailings.

6. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 5, characterized in that: Add cationic activator to the pH-adjusted slurry at a dosage of 105–145 g / t.

7. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cation activation according to claim 5, characterized in that: Add inhibitors at a dosage of 600–1000 g / t; add collectors at a dosage of 285–360 g / t. Add foaming agent at a dosage of 160-260g / t.

8. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 5, characterized in that: The power of the ultrasound is 60-150W; During the flotation process, the stirring speed is 1000–1500 r / min; The pH adjuster used is selected from at least one of HCl and NaOH; The inhibitors used are one or more of water glass, CaO, and sodium carboxymethyl cellulose; The collector used is either kerosene or diesel oil; The foaming agent used is one of terpineol, methyl isobutyl alcohol, or 2-octanol.

9. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 5, characterized in that: After turning on the intake switch, the intake volume is 30-60 L / h.

10. The method for purifying low-grade flake graphite ore by ultrasonic pretreatment combined with cationic activation according to claim 5, characterized in that: The graphite concentrate obtained from the first roughing process has a fixed carbon content of 75-80%, and the graphite recovery rate is greater than or equal to 89%.

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