Method for purification of low-grade flake graphite ore by direct-reverse ion flotation

Abstract

The present application relates to a kind of positive-negative ion activation purification method for low-grade flake graphite ore of reverse flotation;Belong to mineral processing technical field.The present application includes: flake graphite ore is crushed, grinding to grinding granularity-150 mesh is more than 90%, and flake graphite raw ore is obtained;Then it is added to the flotation tank, mixed with water, and the slurry is obtained, pH adjusting agent is added to the slurry, and the pH of slurry is adjusted to 6~9, then various appropriate reagents are sequentially added for positive flotation, and graphite concentrate is obtained;Then the obtained graphite concentrate is mixed with water and added to the flotation tank, and the slurry is prepared;Then pH adjusting agent is added, and the pH of slurry is adjusted to 5~8, then ion activator is added, and then various appropriate reagents are sequentially added for reverse flotation, and the remaining slurry in the flotation tank is flake graphite concentrate.The present application can improve the fixed carbon content of low-grade natural flake graphite ore to more than 87% by one positive flotation and one reverse flotation.

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 forward and reverse flotation ion activation. Background Technology

[0002] Graphite, a material with a variety of unique physical and chemical properties, plays an increasingly important role in modern society. It not only possesses excellent electrical and thermal conductivity, but also outstanding corrosion resistance, high-temperature resistance, and lubricity, making it an indispensable material in many fields such as battery manufacturing, chemical engineering, metal smelting, electronic devices, aerospace, and environmental protection.

[0003] Natural graphite ore is mainly divided into flake graphite and microcrystalline graphite. Flake graphite is primarily used as a raw material for advanced technologies such as batteries and nuclear energy. However, with the acceleration of global industrialization, there are signs of a shortage of high-grade flake graphite ore. Therefore, strengthening research on low-grade flake graphite ore and exploring more economical and efficient purification methods is of great significance for the development of high-precision technologies related to graphite products and for promoting the effective utilization of resources.

[0004] Currently, flotation is the primary purification step for flake graphite. During direct flotation, some large-sized flake graphite pieces are difficult to adhere to bubbles and reach the surface due to their size. Therefore, multi-stage grinding is often used to reduce graphite size, or the air intake is increased to form larger bubbles. However, these large bubbles easily carry small impurities to the surface during their ascent, leading to a decrease in the fixed carbon content of the graphite concentrate. Therefore, exploring a process to solve the problem of small impurity entrainment during flotation while protecting large-sized flake graphite is extremely important. Summary of the Invention

[0005] To address the problems of severe entrainment of large-sized flake graphite during direct flotation and the potential damage to large-sized flake graphite during multi-stage grinding, this invention provides a method for ion activation and purification of low-grade flake graphite ore using direct and reverse flotation. This method aims to both protect large-sized flake graphite and remove impurities entrained during direct flotation, thereby increasing its fixed carbon content. To achieve the above objectives, the following technical solution is adopted:

[0006] This invention discloses a method for purifying low-grade flake graphite ore through forward and reverse flotation ion activation, comprising the following steps:

[0007] Step 1: Crushing and Grinding

[0008] Flake graphite ore is crushed and ground until the grinding particle size of -150 mesh accounts for more than 90% to obtain raw flake graphite ore;

[0009] Step 2: Positive Flotation

[0010] The obtained flake graphite ore is added to a flotation cell, water is added and mixed to obtain a slurry. A pH adjuster is added to the slurry to adjust the pH to 6-9. Then, inhibitor A, collector A and frother A are added in sequence, and then flotation is carried out to obtain graphite concentrate.

[0011] Step 3 Reverse Flotation

[0012] The obtained graphite concentrate is mixed with water and added to a flotation cell to prepare a slurry. Then, a pH adjuster is added to adjust the pH of the slurry to 5-8. Then, an ion activator is added, followed by the sequential addition of inhibitor B, collector B and frother B, and each is stirred. Then, the aeration switch is turned on to carry out reverse flotation. The remaining slurry in the flotation cell is filtered and dried to obtain flake graphite concentrate.

[0013] The ionic activator is selected from at least one of MgCl2, AlCl3 and CaCl2;

[0014] The inhibitor B used in the reverse flotation process is selected from at least one of carboxymethyl cellulose and MF (formaldehyde condensate of sodium methylnaphthalene sulfonate);

[0015] Collector B used in the reverse flotation process is selected from at least one of monoamines, alkyl polyamine ethers, ether monoamines, N-alkylamides, dodecylamine, octadecylamine, kerosene, and sodium oleate;

[0016] The frother B used in the reverse flotation process is selected from at least one of terpineol and octanol;

[0017] During the reverse flotation process, add ion activator at a dosage of 80-320 g / t, add inhibitor B at a dosage of 700-1300 g / t, add collector B at a dosage of 260-420 g / t, and add frother at a dosage of 150-300 g / t.

[0018] This invention discloses a method for ion activation and purification of low-grade flake graphite ore using forward and reverse flotation. The flake graphite ore is first coarsely crushed to obtain a coarse crushed product, and then finely crushed using a crushing and screening machine to obtain a fine crushed product. The fine crushed product is then ground using a crusher to make the mineral particle size of -150 mesh account for more than 90%, thus obtaining raw flake graphite ore.

[0019] The flake graphite ore includes low-grade natural flake graphite ore. In this invention, low-grade natural flake graphite ore includes natural flake graphite ore with a fixed carbon content of less than or equal to 8.5%.

[0020] In industrial applications, natural flake graphite ore is coarsely crushed to 8-35mm with more than 70% of the particles to obtain coarse crushed products. Then, it is finely crushed to 0.1-3mm with more than 70% of the particles to obtain fine crushed products. The obtained fine crushed products are then ground in a sample preparation pulverizer for 2-5 minutes, with a grinding particle size of -150 mesh or more than 90%, to obtain raw flake graphite ore.

[0021] To further enhance its application value, this invention requires a certain fixed carbon content in natural flake graphite ore, specifically a fixed carbon content of 2% or greater, at which point its industrial application value is significantly increased. Of course, a lower fixed carbon content can also be used in this invention, but the cost will be slightly higher.

[0022] In industrial applications, the flake graphite ore obtained from grinding is added to a flotation cell, deionized water is added for mixing, and the mixture is stirred for 2–5 minutes to obtain a flake graphite ore slurry. A pH adjuster is added to adjust the pH of the slurry to 6–9, and the mixture is stirred for 2–5 minutes. Then, inhibitor A and collector A are added sequentially and stirred for 2–5 minutes each. Frothing agent A is then added, and after stirring for 1–3 minutes, the aeration switch is turned on. The froth is then scraped for 3–12 minutes, and the scraped froth is the graphite concentrate. The slurry concentration of the flake graphite ore slurry is 8 wt.%–25 wt.%, preferably 15 wt.%–25 wt.%. The dosage of inhibitor A is 700–1300 g / t, preferably 880–1260 g / t; the dosage of collector A is 260–420 g / t; and the dosage of frother A is 150–300 g / t.

[0023] The crusher used in this invention includes a jaw crusher, and the crushing and screening machine includes a roller crushing and screening machine. Of course, other crushers and crushing and screening machines can also be used in this invention.

[0024] The water used in this invention includes deionized water.

[0025] The flotation machine used in this invention is preferably an XFG5-35 hanging tank flotation machine, but other flotation machines can also be used in this invention.

[0026] The stirring process described in this invention uses a flotation machine impeller for stirring, with a rotation speed of 800-1500 r / min.

[0027] The pH adjuster used in this invention is one of HCl, NaOH and CaO.

[0028] The inhibitor A used in the positive flotation process of this invention is one or more of water glass, CaO, and sodium carboxymethyl cellulose.

[0029] The collector A used in the positive flotation process of this invention is one or more of kerosene and diesel oil.

[0030] The frother A used in the positive flotation process of this invention is one or more of terpineol, methyl isobutyl alcohol, and 2-octanol.

[0031] The air intake rate for the positive flotation process in this invention is 40-60 L / h.

[0032] This invention discloses a method for ion activation and purification of low-grade flake graphite ore using forward and reverse flotation. During reverse flotation, the obtained graphite concentrate is mixed with water at a pulp concentration of 10wt%–20wt% and added to the flotation cell. The mixture is stirred for 2–5 minutes to obtain a pulp. Then, a pH adjuster is added to adjust the pulp pH to 5–8, and the mixture is stirred for 2–5 minutes. An ion activator is added to the pH-adjusted pulp, and the mixture is stirred for 2–5 minutes. Inhibitor B, collector B, and frother B are added sequentially to the pulp containing the ion activator, and the mixture is stirred separately. The aeration switch is then turned on, and reverse flotation is performed. After reverse flotation is completed, the remaining pulp in the flotation cell is the flake graphite concentrate.

[0033] After the flotation process is completed, the remaining slurry in the flotation cell is filtered and dried to obtain flake graphite concentrate.

[0034] In industrial applications, the aeration switch is turned on, and then the frothing process is performed for 4–9 minutes to complete the reverse frothing. After the reverse frothing is completed, the remaining slurry in the flotation cell is filtered and dried to obtain flake graphite concentrate.

[0035] In this invention, an ion activator is added at a dosage of 80–320 g / t during the reverse flotation process. This is because the ion activator used in this invention can react with or selectively adsorb onto the surface of impurities such as quartz, thereby activating the surface and enhancing the adsorption with the collector. However, if too little activator is added, the activation effect will be unsatisfactory, while too much activator will lead to the formation of too many activation sites on the mineral surface, resulting in a decrease in the selectivity of the collector and thus inhibiting the effective flotation separation of the target mineral. Different activators have different chemical interactions and adsorption characteristics with the target mineral surface. Other activators may not be able to form effective chemical bonds and adsorption with the specific functional groups and ions on the surface, thus failing to activate the surface. Moreover, ion hydration strongly affects the ion arrangement at the gas-liquid interface. The enrichment or depletion of ions at the gas-liquid interface changes the liquid film strength of the bubbles, thereby inhibiting bubble bonding, resulting in smaller and more stable average bubble size. The presence of smaller bubbles is more conducive to bonding with smaller minerals during the reverse flotation process, thus facilitating the separation of impurities and minerals.

[0036] As a preferred embodiment, the present invention provides a method for ion activation and purification of low-grade flake graphite ore using forward and reverse flotation. During reverse flotation...

[0037] The obtained graphite concentrate is mixed with water at a ratio of 10% to 20% of the slurry concentration and added to the flotation cell. The mixture is stirred for 2 to 5 minutes to obtain the slurry.

[0038] Add a pH adjuster to the obtained slurry to adjust the pH of the slurry to 5-8, and stir for 2-5 minutes.

[0039] As a preferred embodiment, the present invention provides a method for ion activation and purification of low-grade flake graphite ore using forward and reverse flotation. During reverse flotation...

[0040] Add ion activator to the pH-adjusted slurry at a dosage of 170–220 g / t and stir for 2–5 minutes.

[0041] For natural flake graphite ore with impurities mainly consisting of mica, quartz, feldspar, and silicates, the preferred ion activator is at least one of CaCl2 and MgCl2.

[0042] As a further preferred option, for natural flake graphite minerals whose impurities are mainly mica, quartz, feldspar and silicates, the ion activator is composed of a mixture of CaCl2 and MgCl2.

[0043] As a further preferred option, for natural flake graphite ore with impurities mainly consisting of mica, quartz, feldspar, and silicates, the ion activator is composed of a mixture of MgCl2 and CaCl2, and the amount of MgCl2 added in the ion activator is greater than or equal to the amount of CaCl2 added.

[0044] As a further preferred option, for natural flake graphite ore with impurities mainly consisting of mica, quartz, feldspar, and silicates, the amount of MgCl2 added to the ion activator is 95–125 g / t, and the amount of CaCl2 added is 75–90 g / t.

[0045] As a preferred embodiment, the present invention provides a method for ion activation and purification of low-grade flake graphite ore using forward and reverse flotation. During reverse flotation...

[0046] Add an inhibitor to the slurry after adding the ion activator at a dosage of 1000-1300 g / t and stir for 2-5 minutes. Then add a collector to the slurry with the inhibitor at a dosage of 150-300 g / t and stir for 2-5 minutes. Then add a frother to the slurry with the collector at a dosage of 180-240 g / t. After stirring for 1-3 minutes, turn on the aeration switch and then perform frothing for 4-9 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite concentrate, i.e., graphite concentrate from the reverse flotation process. The froth scraped off is the tailings.

[0047] The pH adjuster used in the reverse flotation process of this invention is one of HCl and H2SO4.

[0048] The collector B used in the reverse flotation process of this invention is first mixed with hydrochloric acid or acetic acid in a ratio of 1:0.8 to 1:1.6, and then diluted with hot water at a temperature of 35 to 50°C to a 0.5% to 2% aqueous solution and stirred thoroughly to prepare the collector. The amount of collector used is relative to the amount of the collector used before mixing with acid and hot water.

[0049] The air intake rate for the reverse flotation process in this invention is 20-50 L / h.

[0050] The graphite concentrate obtained by the reverse flotation process of this invention has a fixed carbon content of ≥80%, and after optimization, the fixed carbon content is ≥85%, or even ≥90%.

[0051] In this invention, the obtained large-size flake graphite, for a single large-size flake graphite, has an equivalent radius of 10 micrometers or more on the side with the largest area, which can be 15 micrometers or more or more than 20 micrometers after optimization.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0053] This invention first employs an appropriate process and parameters to remove most impurities from flake graphite ore using only one direct flotation. Then, a reverse flotation is performed on the direct flotation concentrate, and an appropriate amount and a special type of ion activator are added during the reverse flotation process. This not only protects the large-sized flake graphite from damage but also removes small-particle impurities entrained during the direct flotation process. Moreover, the reverse flotation process, under the synergistic effect of ion activation and flotation process and parameters, can significantly increase the fixed carbon content of the concentrate. Attached Figure Description

[0054] Figure 1 This is a flowchart illustrating a specific embodiment of the present invention.

[0055] Figure 2 The images shown are SEM-EDS images of the positive flotation concentrate in Example 1, where (a) is a 2000x backscattered image of the positive flotation concentrate and (b) is a local surface scan energy spectrum of the positive flotation concentrate.

[0056] Figure 3 This is a SEM-EDS image of the entrainment of the concentrate in Example 1.

[0057] Figure 4 This is a whole SEM-EDS image of the reverse flotation concentrate in Example 1.

[0058] Figure 5 This is a partial SEM-EDS image of the reverse flotation concentrate in Example 1.

[0059] from Figure 1The process of one specific embodiment of the present invention can be seen in the diagram.

[0060] exist Figure 2 In backscattered images, elements with different atomic numbers exhibit different brightness; the higher the atomic number, the brighter the contrast. From Figure 2 (a) It can be seen that the white substance is an impurity, while the black substance is graphite. A large number of impurities still exist in the positive flotation concentrate, and it is obvious that most of the impurities are smaller than the graphite. Measurements show that the impurity size is mostly 6–12 μm, while the graphite size is mostly 18–30 μm. Combined with… Figure 2 (a) Figure 2 (b) It can be seen that the main impurity is silicon, and it also contains a small amount of aluminum, indicating that it contains a large amount of quartz and a small amount of aluminosilicate.

[0061] from Figure 3 It can be seen that a large number of small impurities are aggregated and carried away from the liquid surface by bubbles, resulting in a decrease in the fixed carbon content in the concentrate.

[0062] from Figure 4 It can be seen that, Figure 4 and Figure 2 (a) Backscatter images of the concentrates from direct flotation and reverse flotation at 2000x magnification, respectively. After reverse flotation, Figure 4 Most of the impurities were removed, indicating that the reverse flotation process can effectively remove small-sized impurities.

[0063] from Figure 5 It can be seen that most of the impurities have been removed, with only a very small amount of impurities remaining. Moreover, the surface of the flake graphite is smooth, and the large-sized flake graphite is well protected. Detailed Implementation

[0064] 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.

[0065] A method for purifying low-grade flake graphite ore through forward and reverse flotation ion activation includes the following steps:

[0066] (1) The natural flake graphite ore with a fixed carbon content of 2.68% to 7.98% is coarsely crushed to 8 to 35 mm with more than 70% content to obtain coarse crushed product. Then, it is finely crushed to 0.1 to 3 mm with more than 70% content to obtain fine crushed product.

[0067] (2) Grind the finely crushed product using a sample grinding mill for 2-5 minutes, with the grinding particle size of -150 mesh accounting for more than 90%, to obtain flake graphite raw ore;

[0068] (3) The flake graphite ore obtained in step (2) is mixed with water at a ratio of 8% to 25% of the slurry concentration and added to the flotation cell. The mixture is stirred for 2 to 5 minutes to obtain the slurry.

[0069] (4) Add pH adjuster to the above slurry to adjust the pH of the slurry to 6-9, and stir for 2-5 minutes;

[0070] (5) Add inhibitor to the above-adjusted pH slurry at a dosage of 700-1300 g / t and stir for 2-5 min;

[0071] (6) Add the collector to the above-mentioned slurry with added inhibitor at a dosage of 260-420 g / t and stir for 2-5 min;

[0072] (7) Add frother to the slurry containing the collector at a dosage of 150-300 g / t. After stirring for 1-3 minutes, turn on the aeration switch and then scrape the foam for 3-12 minutes. Filter and dry the scraped foam to obtain the flake graphite rough concentrate, i.e. the graphite concentrate of the positive flotation process. The rest is tailings.

[0073] (8) Mix the graphite concentrate obtained in step (7) with water at a ratio of 10% to 20% of the slurry concentration and add it to the flotation cell. Stir for 2 to 5 minutes to obtain the slurry.

[0074] (9) Add pH adjuster to the slurry obtained in step (8) to adjust the pH of the slurry to 5-8 and stir for 2-5 minutes;

[0075] (10) Add ion activator to the above-adjusted pH slurry at a dosage of 80-320 g / t and stir for 2-5 min;

[0076] (11) Add inhibitor to the slurry after adding ion activator at a dosage of 500-1300 g / t and stir for 2-5 min;

[0077] (12) Add collector to the above-mentioned slurry with added inhibitor at a dosage of 120-380 g / t and stir for 2-5 min;

[0078] (13) Add frother to the slurry with collector added above at a dosage of 100-240 g / t. After stirring for 1-3 minutes, turn on the aeration switch and then scrape the foam for 4-9 minutes. After the foam scraping is completed, filter and dry the remaining slurry in the flotation cell to obtain flake graphite concentrate, i.e. graphite concentrate of reverse flotation process, and the scraped foam is tailings.

[0079] 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.

[0080] In one specific embodiment, the aqueous solution used in step (3) is deionized water.

[0081] In one specific implementation, the flotation machine used in step (3) is an XFG5-35 hanging flotation machine.

[0082] In one specific embodiment, the stirring process in steps (3) to (7) is carried out by stirring with a flotation machine impeller at a speed of 800 to 1500 r / min.

[0083] In one specific embodiment, the pH adjuster used in step (4) is one of HCl, NaOH and CaO.

[0084] In one specific embodiment, the inhibitor used in step (5) is one or more of water glass, CaO, and sodium carboxymethyl cellulose.

[0085] In one specific embodiment, the collector used in step (6) is either kerosene or diesel oil.

[0086] In one specific embodiment, the foaming agent used in step (7) is one of terpineol, methyl isobutyl alcohol, and octanol.

[0087] In one specific implementation, the air intake volume in step (7) is 40-60 L / h.

[0088] In one specific embodiment, the pH adjuster used in step (9) is one of HCl and H2SO4.

[0089] In one specific embodiment, the ionic activator used in step (10) is one or more of MgCl2, AlCl3 and CaCl2.

[0090] In one specific embodiment, the inhibitor used in step (11) is one or more of carboxymethyl cellulose and MF.

[0091] In one specific embodiment, the collector used in step (12) is one or more of the following: monoamine, alkyl polyamine ether, ether monoamine, N-alkylamide, dodecylamine, octadecylamine, kerosene and sodium oleate.

[0092] In one specific embodiment, the monoamine, alkyl polyamine ether, ether monoamine, N-alkylamide, dodecylamine and octadecylamine in the collector used in step (12) are first mixed with hydrochloric acid or acetic acid in a ratio of 1:0.8 to 1:1.6, and then diluted with hot water at a temperature of 35 to 50°C to a 0.5% to 2% aqueous solution and stirred thoroughly to prepare the collector. The amount of collector used is relative to the amount of the collector used before mixing with acid and hot water.

[0093] In one specific embodiment, the foaming agent used in step (13) is one of terpineol and octanol.

[0094] In one specific implementation, the air intake volume in step (13) is 20-50 L / h.

[0095] In one specific embodiment, the fixed carbon content of the graphite concentrate obtained in step (13) can reach 91.37%.

[0096] 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.

[0097] Example 1-1

[0098] The XRD test results of the natural flake graphite ore produced in a mining area in Hunan Province showed that the main impurities were mica, quartz, feldspar and silicates, and its composition is shown in Table 1.

[0099] Table 1. Composition of natural flake graphite (wt%) in a mining area of ​​Hunan Province

[0100]

[0101] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0102] The obtained flake graphite ore was mixed with water at a pulp concentration of 25% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0103] Add 500 g / t water glass and 400 g / t sodium carboxymethyl cellulose inhibitor to the pH-adjusted slurry and stir for 3 min. Then add kerosene at a dosage of 320 g / t and stir for 3 min. Next, add terpineol at a dosage of 220 g / t. After stirring for 1 min, turn on the aeration switch and adjust the air intake to 50 L / h. Then perform froth scraping for 9 min. Filter and dry the scraped froth to obtain flake graphite positive flotation concentrate.

[0104] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0105] Add ion activator to the pH-adjusted slurry at a dosage of 120 g / t MgCl2 and 80 g / t CaCl2, and stir for 4 min;

[0106] Add 700 g / t of inhibitor MF (formaldehyde condensate of sodium methylnaphthalene sulfonate) and 600 g / t of carboxymethyl cellulose to the above-mentioned slurry after adding ion activator, and stir for 3 min;

[0107] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0108] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0109] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. After continuous scale-up testing, the flotation product exhibited the following characteristics: fixed carbon content of 91.37% and recovery rate of 74.55%.

[0110] Recovery rate calculation: Assuming the graphite content in the raw ore is A, and the graphite content in the concentrate obtained after one flotation is B1, then the recovery rate R1 of one flotation is...

[0111]

[0112] If multiple flotation processes are performed, and the recovery rates for each flotation are R1, R2, R3, ..., R... n The total recovery rate R after multiple selections is:

[0113] R = R1 × R2 × R3 × … × R n

[0114] The graphite concentrate obtained by reverse flotation was further refined using 300 g / t of water glass as a depressant, 160 g / t of kerosene as a collector, and 110 g / t of terpineol as a frother. After one refinement, the fixed carbon content in the graphite concentrate increased to 95.31%.

[0115] Examples 1-2

[0116] The other conditions are the same as in Example 1-1, except that:

[0117] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0118] Add ion activator to the pH-adjusted slurry at a dosage of 200 g / t MgCl2 and stir for 4 min;

[0119] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0120] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0121] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0122] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 88.61% and recovery rate of 69.38%.

[0123] Examples 1-3

[0124] The other conditions are the same as in Example 1-1, except that:

[0125] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0126] Add ion activator to the pH-adjusted slurry at a dosage of 200 g / t CaCl2 and stir for 4 min;

[0127] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0128] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0129] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0130] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 87.92% and recovery rate of 68.41%.

[0131] Examples 1-4

[0132] The other conditions are the same as in Example 1-1, except that:

[0133] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0134] Add ion activator to the pH-adjusted slurry at a dosage of 100 g / t CaCl2 + 100 g / t MgCl2, and stir for 4 min;

[0135] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0136] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0137] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0138] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 90.17% and recovery rate of 73.32%.

[0139] Examples 1-5

[0140] The other conditions are the same as in Example 1-1, except that:

[0141] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0142] Add ion activator to the pH-adjusted slurry at a dosage of 120 g / t CaCl2 + 80 g / t MgCl2, and stir for 4 min;

[0143] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0144] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0145] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0146] In the flotation process, natural flake graphite ore was subjected to forward and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 89.56% and recovery rate of 71.35%.

[0147] Example 2

[0148] The XRD results of the natural flake graphite ore produced in a mining area in Yunnan Province show that the main impurities are mica, quartz, feldspar and pyrite, and its composition is shown in Table 2.

[0149] Table 2. Composition of natural flake graphite (wt%) from a mining area in Yunnan Province

[0150]

[0151] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0152] The obtained flake graphite ore was mixed with water at a pulp concentration of 15% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. NaOH was added to the pulp to adjust the pH of the pulp to 9 and stirred for 3 minutes.

[0153] Add 1100 g / t water glass inhibitor to the pH-adjusted slurry and stir for 3 minutes; then add 260 g / t diesel oil and stir for 3 minutes; then add 210 g / t methyl isobutyl methanol and stir for 1 minute. Turn on the aeration switch and adjust the air intake to 50 L / h. Then perform froth scraping for 8 minutes. Filter and dry the scraped froth to obtain flake graphite positive flotation concentrate.

[0154] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 10% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 6, and the mixture was stirred for 3 minutes.

[0155] Add 180 g / t MgCl2 of ion activator to the pH-adjusted slurry and stir for 4 min;

[0156] Add inhibitor MF 1300g / t to the slurry after adding the ion activator and stir for 3min;

[0157] Next, 190 g / t N-alkylamide and hydrochloric acid were mixed in a 1:1 ratio, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation tank. At the same time, 80 g / t sodium oleate was added and stirred for 4 min.

[0158] Add 200g / t of frother terpineol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0159] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 89.16% and recovery rate of 72.91%.

[0160] Example 3

[0161] 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 and feldspar, and its composition is shown in Table 3.

[0162] Table 3. Composition of Natural Flake Graphite from a Mining Area in Henan Province

[0163]

[0164] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0165] The obtained flake graphite ore was mixed with water at a pulp concentration of 20% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0166] Add 1250 g / t water glass inhibitor to the pH-adjusted slurry and stir for 3 minutes; then add 250 g / t kerosene and stir for 3 minutes; then add 240 g / t terpineol and stir for 1 minute. Turn on the aeration switch and adjust the air intake to 50 L / h. Then perform froth scraping for 9 minutes. Filter and dry the scraped froth to obtain flake graphite positive flotation concentrate.

[0167] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0168] Add 180 g / t AlCl3 ion activator to the pH-adjusted slurry and stir for 3 min;

[0169] Add 1200 g / t of carboxymethyl cellulose inhibitor to the slurry after adding the ion activator, and stir for 3 min;

[0170] Next, 280 g / t alkyl polyamine ether was mixed with acetic acid at a ratio of 1:1.3, then diluted with 45°C hot water to a 1.5% aqueous solution and stirred thoroughly before being added to the flotation tank and stirred for 3 minutes.

[0171] Add 240 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0172] In the flotation process, natural flake graphite ore was subjected to forward and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 88.64% and recovery rate of 71.03%.

[0173] Comparative Example 1

[0174] The other conditions are the same as the forward flotation process in Example 1, except that reverse flotation is not performed; that is:

[0175] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0176] The obtained flake graphite ore was mixed with water at a pulp concentration of 25% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0177] Add 500 g / t water glass and 400 g / t sodium carboxymethyl cellulose inhibitor to the pH-adjusted slurry and stir for 3 min. Then add kerosene at a dosage of 320 g / t and stir for 3 min. Next, add terpineol at a dosage of 220 g / t. After stirring for 1 min, turn on the aeration switch and adjust the air intake to 50 L / h. Then perform frothing for 9 min. Filter and dry the froth to obtain flake graphite positive flotation concentrate.

[0178] 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 53.27% and recovery rate of 82.30%.

[0179] Comparative Example 2

[0180] Other conditions are the same as the forward-reverse flotation process in Example 1, except that no ion activator is added during the reverse flotation process; that is:

[0181] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0182] The obtained flake graphite ore was mixed with water at a pulp concentration of 25% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0183] Add 500 g / t water glass and 400 g / t sodium carboxymethyl cellulose inhibitor to the pH-adjusted slurry and stir for 3 min. Then add kerosene at a dosage of 320 g / t and stir for 3 min. Next, add terpineol at a dosage of 220 g / t. After stirring for 1 min, turn on the aeration switch and adjust the air intake to 50 L / h. Then perform froth scraping for 9 min. Filter and dry the scraped froth to obtain flake graphite positive flotation concentrate.

[0184] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0185] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the pH-adjusted slurry and stir for 3 min;

[0186] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0187] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0188] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 83.91% and recovery rate of 72.13%.

[0189] Comparative Example 3

[0190] Other conditions are the same as the forward-reverse flotation process in Example 1, except that the amount of ion activator used in the reverse flotation process is not within the protection range of 80-320 g / t of this invention.

[0191] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0192] The obtained flake graphite ore was mixed with water at a pulp concentration of 25% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0193] Add 500 g / t water glass and 400 g / t sodium carboxymethyl cellulose inhibitor to the pH-adjusted slurry and stir for 3 min. Then add 320 g / t kerosene and stir for 3 min. Next, add 220 g / t terpineol and stir for 1 min. Then turn on the aeration switch and adjust the air intake to 50 L / h. Then perform frothing for 9 min. Filter and dry the froth to obtain flake graphite positive flotation concentrate.

[0194] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0195] Add ion activator to the pH-adjusted slurry at a dosage of 240 g / t MgCl2 and 160 g / t CaCl2, and stir for 4 min;

[0196] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0197] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0198] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0199] In the flotation process, natural flake graphite ore was subjected to forward and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 79.33% and recovery rate of 67.60%.

[0200] Comparative Example 4

[0201] Other conditions are the same as the forward-reverse flotation process in Example 1, except that the amount of inhibitor used in the reverse flotation process is outside the protection range of 500-1300 g / t of this invention.

[0202] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0203] The obtained flake graphite ore was mixed with water at a pulp concentration of 25% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0204] Add 500 g / t water glass and 400 g / t sodium carboxymethyl cellulose inhibitor to the pH-adjusted slurry and stir for 3 min. Then add 320 g / t kerosene and stir for 3 min. Next, add 220 g / t terpineol and stir for 1 min. Then turn on the aeration switch and adjust the air intake to 50 L / h. Then perform frothing for 9 min. Filter and dry the froth to obtain flake graphite positive flotation concentrate.

[0205] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0206] Add ion activator to the pH-adjusted slurry at a dosage of 120 g / t MgCl2 and 80 g / t CaCl2, and stir for 4 min;

[0207] Add 800 g / t of inhibitor MF and 800 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0208] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0209] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0210] In the flotation process, natural flake graphite ore was subjected to forward and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 78.63% and recovery rate of 62.80%.

[0211] Comparative Example 5

[0212] Other conditions are the same as the forward-reverse flotation process in Example 1, except that the collector dosage in the reverse flotation process is not within the 120-380 g / t range protected by this invention.

[0213] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0214] The obtained flake graphite ore was mixed with water at a pulp concentration of 25% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0215] Add 500 g / t water glass and 400 g / t sodium carboxymethyl cellulose inhibitor to the pH-adjusted slurry and stir for 3 min. Then add 320 g / t kerosene and stir for 3 min. Next, add 220 g / t terpineol and stir for 1 min. Then turn on the aeration switch and adjust the air intake to 50 L / h. Then perform frothing for 9 min. Filter and dry the froth to obtain flake graphite positive flotation concentrate.

[0216] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0217] Add ion activator to the pH-adjusted slurry at a dosage of 120 g / t MgCl2 and 80 g / t CaCl2, and stir for 4 min;

[0218] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0219] Next, 240 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 180 g / t kerosene was added and stirred for 4 minutes.

[0220] Add 190 g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30 L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0221] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 81.29% and recovery rate of 68.35%.

[0222] Comparative Example 6

[0223] Other conditions are the same as the forward-reverse flotation process in Example 1, except that the amount of frother used in the reverse flotation process is not within the 100-240 g / t range protected by this invention.

[0224] The natural flake graphite ore is first crushed to 8-35mm or more (70% or more) using an XPC-100X60 jaw crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm or more (70% or more) using an XPS-Ф250×150 roller crusher and screener to obtain a fine crushed product. The obtained fine crushed product is then ground for 4 minutes using a sample preparation pulverizer, with a grinding particle size of -150 mesh or more (90% or more) to obtain the raw flake graphite ore.

[0225] The obtained flake graphite ore was mixed with water at a pulp concentration of 25% and added to the flotation cell. The pulp was stirred for 3 minutes to obtain a pulp. HCl was added to the pulp to adjust the pH of the pulp to 8 and stirred for 3 minutes.

[0226] Add 500 g / t water glass and 400 g / t sodium carboxymethyl cellulose inhibitor to the pH-adjusted slurry and stir for 3 min. Then add 320 g / t kerosene and stir for 3 min. Next, add 220 g / t terpineol and stir for 1 min. Then turn on the aeration switch and adjust the air intake to 50 L / h. Then perform frothing for 9 min. Filter and dry the froth to obtain flake graphite positive flotation concentrate.

[0227] The graphite concentrate obtained from the positive flotation was mixed with water at a pulp concentration of 15% and added to the flotation cell. The mixture was stirred for 3 minutes to obtain a pulp. H2SO4 was added to the obtained pulp to adjust the pH of the pulp to 7, and the mixture was stirred for 3 minutes.

[0228] Add ion activator to the pH-adjusted slurry at a dosage of 120 g / t MgCl2 and 80 g / t CaCl2, and stir for 4 min;

[0229] Add 700 g / t of inhibitor MF and 600 g / t of carboxymethyl cellulose to the slurry after adding the ion activator, and stir for 3 min;

[0230] Next, 160 g / t dodecylamine and hydrochloric acid were mixed in a ratio of 1:1.2, then diluted with 40°C hot water to a 1% aqueous solution and stirred thoroughly before being added to the flotation cell. At the same time, 100 g / t kerosene was added and stirred for 4 minutes.

[0231] Add 300g / t of frother octanol to the slurry containing the collector. After stirring for 1 minute, turn on the aeration switch and set the air intake to 30L / h. Then, perform frothing for 7 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite reverse flotation concentrate.

[0232] In the flotation process, natural flake graphite ore was subjected to direct and reverse flotation under ambient temperature conditions. The flotation product obtained after continuous scale-up testing had the following specifications: fixed carbon content of 86.11% and recovery rate of 72.68%.

Claims

1. A method for ion activation and purification of low-grade flake graphite ore using forward and reverse flotation, characterized in that, Includes the following steps: Step 1: Crushing and Grinding Flake graphite ore is crushed and ground until the grinding particle size of -150 mesh accounts for more than 90% to obtain raw flake graphite ore; Step 2: Positive Flotation The obtained flake graphite ore is added to a flotation cell, water is added and mixed to obtain a slurry. A pH adjuster is added to the slurry to adjust the pH to 6-9. Then, inhibitor A, collector A and frother A are added in sequence, and then flotation is carried out to obtain graphite concentrate. Step 3 Reverse Flotation The obtained graphite concentrate is mixed with water and added to a flotation cell to prepare a slurry. Then, a pH adjuster is added to adjust the pH of the slurry to 5-8. Then, an ion activator is added, followed by the sequential addition of inhibitor B, collector B and frother B, and each is stirred. Then, the aeration switch is turned on to carry out reverse flotation. The remaining slurry in the flotation cell is filtered and dried to obtain flake graphite concentrate. The ionic activator is selected from at least one of MgCl2, AlCl3 and CaCl2; The inhibitor B used in the reverse flotation process is selected from at least one of carboxymethyl cellulose and sodium methylnaphthalene sulfonate formaldehyde condensate; Collector B used in the reverse flotation process is selected from at least one of monoamines, alkyl polyamine ethers, ether monoamines, N-alkylamides, dodecylamine, octadecylamine, kerosene, and sodium oleate; The frother B used in the reverse flotation process is selected from at least one of terpineol and 2-octanol; During the reverse flotation process, add ion activator at a dosage of 80-320 g / t and inhibitor B at a dosage of 700-1300 g / t; Add collector B at a dosage of 260–420 g / t and foaming agent at a dosage of 150–300 g / t.

2. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: First, the flake graphite ore is coarsely crushed to obtain coarse crushed product. Then, it is finely crushed using a crushing and screening machine to obtain fine crushed product. The fine crushed product is then ground using a crusher to make the mineral particle size of -150 mesh account for more than 90%, thus obtaining the raw flake graphite ore.

3. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: Natural flake graphite ore is coarsely crushed to 8-35mm (70% or more) using a crusher to obtain a coarse crushed product. Then, it is finely crushed to 0.1-3mm (70% or more) using a crushing and screening machine to obtain a fine crushed product. The obtained fine crushed product is then ground in a sample preparation pulverizer for 2-5 minutes, with a grinding particle size of -150 mesh (90% or more) to obtain raw flake graphite ore.

4. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: The raw flake graphite ore obtained from grinding is added to a flotation cell, deionized water is added for mixing, and the mixture is stirred for 2-5 minutes to obtain a raw flake graphite ore slurry. A pH adjuster is added to adjust the pH of the slurry to 6-9, and the mixture is stirred for 2-5 minutes. Then, inhibitor A and collector A are added sequentially and stirred for 2-5 minutes each. Frothing agent A is then added. After stirring for 1-3 minutes, the aeration switch is turned on, and the froth is scraped for 3-12 minutes. The scraped froth is the graphite concentrate. The slurry concentration of the raw flake graphite ore slurry is 8wt%-25wt%. The dosage of inhibitor A is 700-1300 g / t; the dosage of collector A is 260-420 g / t; and the dosage of frother A is 150-300 g / t.

5. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 4, characterized in that: The pulp concentration of flake graphite ore pulp is 15wt%~25wt%; the dosage of inhibitor A is 880~1260g / t.

6. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: The inhibitor A used in the positive flotation process is one or more of water glass, CaO, and sodium carboxymethyl cellulose. Collector A used in the positive flotation process is one or more of kerosene and diesel oil; The frother A used in the positive flotation process is one or more of terpineol, methyl isobutyl alcohol, and 2-octanol; The air intake for the positive flotation process is 40-60 L / h.

7. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: During reverse flotation, the obtained graphite concentrate is mixed with water at a pulp concentration of 10wt% to 20wt% and added to the flotation cell. The mixture is stirred for 2 to 5 minutes to obtain a pulp. Then, a pH adjuster is added to adjust the pH of the pulp to 5 to 8, and the mixture is stirred for 2 to 5 minutes. An ion activator is added to the pH-adjusted pulp, and the mixture is stirred for 2 to 5 minutes. Inhibitor B, collector B, and frother B are added to the pulp containing the ion activator in sequence and stirred separately. Then, the aeration switch is turned on, and reverse flotation is performed. After the reverse flotation is completed, the remaining pulp in the flotation cell is the flake graphite concentrate.

8. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: During reverse flotation, The obtained graphite concentrate is mixed with water at a ratio of 10% to 20% of the slurry concentration and added to the flotation cell. The mixture is stirred for 2 to 5 minutes to obtain the slurry. Add a pH adjuster to the obtained slurry to adjust the pH of the slurry to 5-8, and stir for 2-5 minutes; During reverse flotation, add ion activator to the slurry after pH adjustment at a dosage of 170-220 g / t and stir for 2-5 minutes.

9. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: For natural flake graphite minerals whose main impurities are mica, quartz, feldspar and silicates, the ionic activator is at least one of CaCl2 and MgCl2.

10. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 9, characterized in that: The ionic activator is composed of a mixture of CaCl2 and MgCl2.

11. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 9, characterized in that: The ionic activator is composed of a mixture of MgCl2 and CaCl2, and the amount of MgCl2 added to the ionic activator is greater than or equal to the amount of CaCl2 added.

12. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 10, characterized in that: The amount of MgCl2 added to the ionic activator is 95~125g / t, and the amount of CaCl2 added is 75~90g / t.

13. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: During reverse flotation, Add an inhibitor to the slurry after adding the ion activator at a dosage of 1000-1300 g / t and stir for 2-5 minutes. Then add a collector to the slurry with the inhibitor at a dosage of 150-300 g / t and stir for 2-5 minutes. Then add a frother to the slurry with the collector at a dosage of 180-240 g / t. After stirring for 1-3 minutes, turn on the aeration switch and then perform frothing for 4-9 minutes. After the frothing is finished, filter and dry the remaining slurry in the flotation cell to obtain flake graphite concentrate, i.e., graphite concentrate from the reverse flotation process. The froth scraped off is the tailings.

14. The method for purifying low-grade flake graphite ore by forward and reverse flotation ion activation according to claim 1, characterized in that: The pH adjuster used in the reverse flotation process is either HCl or H2SO4; Collector B used in the reverse flotation process is first mixed with hydrochloric acid or acetic acid in a ratio of 1:0.8 to 1:1.6, and then diluted with hot water at a temperature of 35 to 50°C to a 0.5% to 2% aqueous solution and stirred thoroughly to prepare the collector. The amount of collector used is relative to the amount of the collector used before mixing with acid and hot water. The air intake for the reverse flotation process is 20–50 L / h.

Images