A beneficiation method for high-talc molybdenum ore based on mineral crystal anisotropy

Abstract

This invention discloses a beneficiation method for high-talc molybdenum ore based on the anisotropy of mineral crystals, comprising the following steps: 1) grinding of the raw ore; 2) molybdenum pre-selection; 3) regrinding with planetary ball mill; 4) molybdenum reverse flotation; and 5) molybdenum direct flotation. Based on the anisotropy of mineral crystals, this invention changes the grinding method by using planetary ball milling, exposing more easily oxidized and hydrophilic end faces of molybdenite before it enters the flotation stage, reducing the difference in hydrophilicity and hydrophobicity of the mineral surface controlled by flotation. Then, by adding the oxidant sodium persulfate and the combined inhibitors dextran and polyepoxysuccinic acid, the hydrophilicity of the molybdenite surface is synergistically enhanced, resulting in talc concentrate and molybdenum rough concentrate. The grade of the molybdenum rough concentrate is then improved through molybdenum direct flotation. This beneficiation method eliminates the need for pre-selection to remove talc, reducing the loss of molybdenum ore during desliming. Using this method, a molybdenum grade of not less than 50% and a molybdenum recovery rate of not less than 72% can be obtained in the molybdenum concentrate, achieving efficient flotation separation of high-talc molybdenum ore.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a beneficiation method for high talc molybdenum ore based on the anisotropy of mineral crystals. Background Technology

[0002] Molybdenum possesses excellent properties such as electrical and thermal conductivity, wear resistance, and corrosion resistance, playing a crucial role in strategic emerging industries such as national defense, aerospace, and more. Molybdenite is the most valuable molybdenum mineral, accounting for over 99% of the world's molybdenum production. my country has abundant molybdenum reserves, but its resource endowment is poor, with a large proportion of low-grade, fine-grained, and complex molybdenum ores. In recent years, with rapid economic development, the demand for molybdenum has also increased, making the efficient development of difficult-to-process molybdenum ore resources particularly important.

[0003] High-talc molybdenum ore is a typical difficult-to-process molybdenum ore. While reserves of this type of ore are relatively abundant, researchers both domestically and internationally have conducted extensive research on its beneficiation. Although some progress has been made, the beneficiation indicators remain unsatisfactory. Because both molybdenite and talc have good natural hydrophobicity, and talc is soft and easily turns into mud, leading to a tendency for slime to form, talc severely interferes with molybdenite flotation during the beneficiation process, thus hindering the efficient utilization of this type of resource.

[0004] For the flotation of high-talc molybdenum ore, the conventional flotation process, "raw ore grinding—talc removal—molybdenum pre-selection—conventional ball milling and regrinding—molybdenum positive flotation (talc-suppressed molybdenum flotation)," is widely used both domestically and internationally. However, this process has the following problems: ① Because both talc and molybdenite have good natural floatability, some molybdenum is lost in the desliming product during talc removal; ② During molybdenum positive flotation, talc not only severely interferes with molybdenite flotation but also enters the molybdenum concentrate along with the molybdenite, reducing the molybdenum concentrate grade; ③ During molybdenum positive flotation, the use of macromolecular inhibitors (such as carboxymethyl cellulose, lignin sulfonate, humic acid, etc.) to suppress talc not only results in large reagent dosages and high reagent costs but also poor selectivity and a certain inhibitory effect on molybdenum. Therefore, using this conventional flotation process results in low molybdenum grade and recovery rate in the molybdenum concentrate. Furthermore, using this conventional flotation process presents significant challenges in wastewater treatment and reuse.

[0005] Therefore, developing new methods for efficient beneficiation of high-talc molybdenum ore to achieve efficient flotation separation of molybdenite and talc is key to solving the problem of efficient recovery of molybdenum metal resources. Summary of the Invention

[0006] The purpose of this invention is to propose a highly efficient beneficiation method for high-talc molybdenum ore based on the anisotropy of mineral crystals. Unlike conventional molybdenum beneficiation processes, this invention adopts a process flow of "raw ore grinding—molybdenum pre-selection—planetary ball milling and regrinding—molybdenum reverse flotation (molybdenum-suppressing talc)—molybdenum forward flotation," which can obtain high-grade and high-recovery molybdenum concentrate products.

[0007] The beneficiation method for high-talc molybdenum ore provided by this invention includes the following steps:

[0008] (1) Grinding of raw ore: After crushing the raw ore, wet ball milling is performed to obtain slurry 1;

[0009] (2) Molybdenum pre-selection: gangue inhibitor and slurry dispersant water glass + sodium hexametaphosphate, molybdenum collector butyl xanthate and kerosene, and frother methyl isobutyl methanol (MIBC) were added to slurry 1 in sequence to carry out molybdenum pre-selection and obtain pre-selected molybdenum concentrate and tailings 1;

[0010] (3) Planetary ball mill regrinding: The pre-selected molybdenum concentrate obtained in step (2) is regrinded using a planetary ball mill to obtain slurry 2;

[0011] (4) Molybdenum reverse flotation (molybdenum-suppressed talc): Sodium carbonate is added to slurry 2 to adjust the pH value of the slurry to the set range, and then sodium persulfate, dextran, polyepoxysuccinic acid (PESA) and MIBC are added in sequence to carry out molybdenum reverse flotation to obtain talc concentrate and molybdenum rough concentrate.

[0012] (5) Molybdenum positive flotation: Add collector butyl xanthate, inhibitor water glass + sodium hexametaphosphate, collector kerosene and MIBC to the molybdenum rough concentrate obtained in step (4) in sequence to carry out molybdenum positive flotation to obtain molybdenum concentrate and tailings 2.

[0013] The relative content of talc in the high-talc molybdenum ore is 10%-30%.

[0014] Preferably, in step (1), the fineness of the raw ore grinding is -0.074 mm, accounting for 75% to 90%.

[0015] Preferably, in step (2), the molybdenum pre-selection process consists of one roughing, three scavenging, and three pre-cleaning stages. The roughing concentrate after roughing enters the pre-cleaning stage, and the roughing tailings are scavenged. The specific process flow and reagent system for molybdenum pre-selection are as follows:

[0016] Roughing: Add 300-2000 g / t of water glass and 100-2000 g / t of sodium hexametaphosphate to slurry 1 simultaneously, and stir for 2-3 minutes. The mass ratio of water glass to sodium hexametaphosphate is (3-2):1. Then add 50-600 g / t of butyl xanthate and stir for 2-3 minutes; 25-200 g / t of kerosene and stir for 2-3 minutes; 0-100 g / t of methyl isobutyl methanol (MIBC) and stir for 1-2 minutes. Perform flotation and skim-over for 3-6 minutes.

[0017] Scavenging step 1: Add 25-300g / t of butyl xanthate in sequence, stir for 2-3 minutes; add 13-100g / t of kerosene, stir for 2-3 minutes, and perform flotation and skimming for 1-5 minutes;

[0018] Scavenging step 2: Add 12-150 g / t of butyl xanthate in sequence, stir for 2-3 min; add 7-50 g / t of kerosene, stir for 2-3 min, and perform flotation and skimming for 1-5 min;

[0019] Scavenging step 3: Add 6-75 g / t of benzoyl peroxide in sequence, stir for 2-3 min; add 3-25 g / t of kerosene, stir for 2-3 min, and then perform flotation and skimming for 1-5 min;

[0020] Pre-selection 1: Simultaneously add 150-1000g / t of water glass and 50-1000g / t of sodium hexametaphosphate, stir for 2-3 minutes, and perform flotation and skimming for 2-5 minutes, wherein the mass ratio of water glass to sodium hexametaphosphate is (3-2):1;

[0021] Pre-selection 2: Add 75-500g / t of water glass, stir for 2-3 minutes, and perform flotation and skimming for 1-5 minutes;

[0022] Pre-selection step 3: Blank selection, flotation and bubble scraping for 1-5 minutes.

[0023] Preferably, in step (2), all intermediate mines are returned to the previous level operation in sequence.

[0024] Preferably, in step (3), the fineness of the pre-selected molybdenum concentrate after regrinding is -0.037 mm, accounting for 80% to 95%.

[0025] Preferably, in step (4), sodium carbonate is used to adjust the pH of the slurry to 8.0-9.5.

[0026] Preferably, in step (4), the molecular formula of the polyepoxysuccinic acid is HO(C4R2O5M2). n H, with a relative molecular mass of 400-1500, has the following structural formula:

[0027]

[0028] Where n = 2 - 10, and M is Na + H + or NH4 + R is H or C 14 alkyl.

[0029] Preferably, in step (4), the process flow of molybdenum reverse flotation is one roughing, two scavenging, and two cleaning stages. The roughing concentrate after roughing enters the cleaning stage, and the roughing tailings enter the scavenging stage. The specific process flow and reagent system of molybdenum reverse flotation are as follows:

[0030] Roughing: Add sodium carbonate to adjust the pulp pH to 8.0-9.5, then add sodium persulfate 50-300 g / t, stirring for 2-3 min; dextran 50-300 g / t, stirring for 2-3 min; PESA 25-150 g / t, stirring for 2-3 min; MIBC 0-30 g / t, stirring for 1-2 min; and flotation skimming for 3-6 min. The mass ratio of sodium persulfate, dextran, and PESA is (3-1):1:(2-0.2).

[0031] Sweeping and Selecting Method 1: Add 0-15 g / t of MIBC, stir for 1-2 minutes, and skim off the bubbles for 1-4 minutes;

[0032] Scavenging 2: Add 0-7 g / t of MIBC, stir for 1-2 minutes, and skim off the bubbles for 1-3 minutes;

[0033] Selected Method 1: Add 12-75g / t of PESA, stir for 2-3 minutes, and skim off the bubbles during flotation for 2-3 minutes;

[0034] Selected option 2: Add 6-35g / t of PESA, stir for 2-3 minutes, and perform flotation and skimming for 1-3 minutes.

[0035] Preferably, in step (4), all intermediate mines are returned to the previous level operation in sequence.

[0036] Preferably, in step (5), the process flow of molybdenum positive flotation is one roughing, two scavenging, and two cleaning stages. The roughing concentrate after roughing enters the cleaning stage, and the roughing tailings enter the scavenging stage. The specific process flow and reagent system of molybdenum positive flotation are as follows:

[0037] Roughing: First, add 50-500 g / t of butyl xanthate and stir for 2-3 minutes. Then, simultaneously add 200-1000 g / t of water glass and 100-1000 g / t of sodium hexametaphosphate and stir for 2-3 minutes. Next, add 3-100 g / t of kerosene and stir for 2-3 minutes, then add 0-100 g / t of MIBC and stir for 1-2 minutes. Perform flotation and skimming for 1-5 minutes. The mass ratio of water glass to sodium hexametaphosphate is (3-2):1.

[0038] Scavenging method 1: Add 1-50g / t of kerosene, stir for 2-3 minutes, and perform flotation and skimming for 1-3 minutes;

[0039] Scavenging and separation 2: Add 1-25g / t of kerosene, stir for 2-3 minutes, and perform flotation and skimming for 1-3 minutes;

[0040] Selected Method 1: Simultaneously add 100-500 g / t of water glass and 50-500 g / t of sodium hexametaphosphate, stir for 2-3 minutes, and perform flotation and skimming for 1-3 minutes; wherein the mass ratio of water glass to sodium hexametaphosphate is (3-2):1;

[0041] Selected option 2: Add 0-250g / t of water glass and 0-250g / t of sodium hexametaphosphate, stir for 2-3 minutes, and perform flotation and skimming for 1-2 minutes.

[0042] Preferably, in step (5), all intermediate mines are returned to the previous level operation in sequence.

[0043] In this invention, both kerosene and MIBC are non-water-soluble agents, and are added directly using a syringe according to the dosage requirements;

[0044] In steps (2) and (5), water glass, sodium hexametaphosphate, and butyl xanthate are added to the slurry in the form of solutions, wherein the mass concentration of the water glass solution is 3% to 5%, the mass concentration of the sodium hexametaphosphate solution is 3% to 5%, and the mass concentration of the butyl xanthate solution is 0.5% to 2%.

[0045] In step (4), sodium persulfate, dextran, and PESA are added to the slurry in the form of solutions, wherein the mass concentration of the sodium persulfate solution is 0.5% to 2%, the mass concentration of the dextran solution is 0.5% to 2%, and the mass concentration of the PESA solution is 0.5% to 2%.

[0046] The beneficiation method described in this invention is applicable not only to the beneficiation of high-talc molybdenum ore but also to the beneficiation of pre-refined molybdenum concentrate (molybdenite / talc mixed concentrate). When beneficiating pre-refined molybdenum concentrate (molybdenite / talc mixed concentrate), the latter part of the beneficiation method described in this invention can be directly applied: "planetary ball milling and regrinding of molybdenite / talc mixed concentrate—molybdenum reverse flotation (molybdenum suppression and talc flotation)—molybdenum direct flotation".

[0047] In this invention, "g / t" refers to the amount of reagent added relative to the raw ore or molybdenum pre-selected concentrate (molybdenite / talc mixed concentrate). For example, the amount of water glass added is 500g / t. Depending on the beneficiation target, this means that 500g of water glass needs to be added to process 1 ton of raw ore or molybdenum pre-selected concentrate.

[0048] The principle of this invention:

[0049] Both molybdenite and talc are layered minerals. During grinding, due to their different bond-breaking mechanisms, they expose two crystal planes with distinct surface physicochemical properties (such as wettability, surface electrical properties, and surface oxidizability): the basal plane and the end face. Studies have found that the basal plane of molybdenite is hydrophobic, while the end face is hydrophilic. Furthermore, the basal plane is less susceptible to oxidation and more stable, while the end face is easily oxidized. Unlike conventional ball milling, which only reduces the particle size of minerals, planetary ball milling involves the grinding balls and grinding jar moving together under the combined influence of rotational deflection forces. This generates high energy that pulverizes the sample. The centrifugal force acting on the jar drives the grinding balls in the direction of rotation. Due to the different speeds of the grinding jar wall and the balls, friction and impact occur between the sample and the grinding wall, releasing enormous energy. Planetary ball milling is a high-energy ball milling technology. Under the action of external mechanical forces, it not only reduces the particle size and increases the specific surface area of ​​minerals, but also causes lattice deformation, dislocations, and defects, leading to the transformation from crystalline to amorphous states. It may also induce chemical reactions such as decomposition and redox reactions. Meanwhile, changes in particle size also affect the electronic structure of the solid, particularly altering the band gap. Studies have found that different grinding conditions can effectively change the facet ratio of molybdenite, thereby controlling its flotation recovery rate. Among these, planetary ball milling resulted in the highest number of exposed facets, the largest facet ratio, and the worst floatability for molybdenite as the particle size decreased. In contrast, the floatability of talc remained unaffected by grinding conditions and particle size changes; the talc surface remained strongly hydrophobic (e.g., ...). Figure 1 (As shown). This illustrates that, unlike other grinding methods, planetary ball milling allows for pre-adjustment of the hydrophilicity / hydrophobicity of molybdenite and talc surfaces during the grinding stage before flotation. This increases the number of hydrophilic end faces of molybdenite, making its surface more hydrophilic, thus providing a basis for further expanding the hydrophilic / hydrophobic difference between the two surfaces using reagents in the subsequent flotation operation, reducing the difficulty of flotation control. Therefore, based on the anisotropy of mineral crystals, this invention innovatively proposes a new flotation process: "raw ore grinding—molybdenum pre-selection—planetary ball milling regrinding—molybdenum reverse flotation (molybdenum suppression and talc flotation)—molybdenum forward flotation (improving molybdenum grade)". In this process, talc is no longer removed beforehand, thereby reducing molybdenum loss in this operation. Through planetary ball milling, more hydrophilic end faces of molybdenite are exposed. Based on this, by adding flotation reagents, the inhibition of molybdenite is strengthened, further expanding the hydrophilic / hydrophobic difference between the surfaces of molybdenite and talc, achieving efficient reverse flotation separation of molybdenite and talc. To ensure the molybdenum grade in the molybdenum concentrate, the reverse flotation molybdenum concentrate is subjected to further molybdenum flotation to further improve the molybdenum grade.

[0050] In addition, unlike oxidized talc, molybdenite is a sulfide mineral with redox properties. After planetary ball milling and regrinding, reverse flotation occurs, and molybdenite and talc mainly exist in fine-grained form. The finer the molybdenite particle size, the more exposed end faces it has, which are easily oxidized. First, the addition of sodium persulfate oxidant oxidizes the molybdenite end faces to form MoO3, generating more low-coordination-number surface metal atoms. This provides metal active sites for PESA and dextran adsorption, promoting high-density adsorption of both on the molybdenite surface and enhancing its hydrophilicity. Second, high-molecular-weight dextran has a flocculating effect, selectively adsorbing onto the surface of fine-grained molybdenite in the slurry. Through bridging, it flocculates the fine-grained molybdenite, increasing its apparent particle size and preventing it from floating with talc into the talc concentrate. This strengthens the inhibition of fine-grained molybdenite and ensures molybdenum recovery. Third, PESA has a strong metal ion complexing ability, capable of complexing Mg produced by the dissolution of talc surface in the slurry. 2+ Ions weaken the interactions between minerals, which is more conducive to the flotation separation of molybdenite and talc. Fourth, molybdenum concentrate obtained by reverse flotation is subjected to molybdenum direct flotation. Studies have shown that suppressed molybdenite can regain its floatability under the action of collectors. Xanthate collectors have good selective collecting ability for sulfide molybdenite. Preferential addition of butyl xanthate can form a hydrophobic layer on the surface of molybdenite, which hinders the adsorption of water glass + sodium hexametaphosphate on the surface of molybdenite. Then, the addition of kerosene can efficiently collect molybdenite. This operation can enhance the separation of molybdenite and talc by changing the order of adding inhibitors and collectors, and further improve the molybdenum grade in molybdenum concentrate.

[0051] The beneficial effects of this invention are:

[0052] For refractory molybdenum ores with high talc content, this invention, based on the anisotropy of mineral crystals, employs a process flow of "raw ore grinding—molybdenum pre-selection—planetary ball milling regrinding—molybdenum reverse flotation (suppressing molybdenum flotation of talc)—molybdenum direct flotation (improving molybdenum grade)". Regrinding utilizes planetary ball milling, and by controlling the grinding fineness, more hydrophilic end faces of molybdenite are exposed. Then, a combination of sodium persulfate as an oxidant and dextran + PESA as an organic inhibitor is used to suppress the flotation of talc from molybdenite, achieving efficient reverse flotation separation of the two. The molybdenum rough concentrate obtained from reverse flotation is then subjected to direct flotation to float molybdenum. By adding a collector first and then an inhibitor, molybdenum loss is reduced, and while ensuring molybdenum recovery, the molybdenum grade is effectively improved. Using this invention's process to separate refractory molybdenum ores with high talc content, a molybdenum concentrate product with a molybdenum grade of not less than 50% and a molybdenum recovery rate of not less than 72% can be obtained.

[0053] This invention avoids pre-selective removal of some talc, thus reducing the loss of molybdenite during talc removal in conventional flotation processes. In the regrinding operation, by changing the conventional grinding method to planetary ball milling, more hydrophilic and easily oxidized end faces are induced in molybdenite, reducing its floatability and significantly reducing the difficulty of controlling the hydrophilic / hydrophobic differences of mineral surfaces solely through flotation reagents. In the reverse flotation operation, the synergistic effect of oxidants and inhibitors selectively inhibits molybdenite while largely not inhibiting talc, thereby achieving efficient flotation separation of molybdenite and talc. The molybdenite inhibitor described in this invention is a combination of PESA and the conventional polymeric inhibitor dextran; the reagent has good water solubility, is simple to prepare, and is easy to implement industrially. Attached Figure Description

[0054] Figure 1 The effects of different grinding methods on the flotation behavior of molybdenite and talc;

[0055] Figure 2 The flotation process flow of Example 1 is as follows;

[0056] Figure 3 The flotation process flow is shown in Comparative Example 8;

[0057] Figure 4 The flotation process flow is shown in Example 7;

[0058] Figure 5 The flotation process flow is for Comparative Example 9. Detailed Implementation

[0059] In the following examples and comparative examples, all the reagents used were commercially available. The molecular weight of the dextran was 396.4.

[0060] Example 1

[0061] A high-talc molybdenum ore deposit (1) in Henan Province was obtained and analyzed. The main valuable element in the ore was molybdenum (0.12%), with grades of Fe 10.56%, SiO₂ 46.82%, MgO 16.11%, CaO 11.40%, and Al₂O 35.62%. Molybdenum phase analysis showed that molybdenum accounted for 83.53% of the sulfide phases in the ore. Combined with mineral composition analysis, the molybdenum mineral in the ore was molybdenite, with other metallic sulfides mainly being magnetite, and non-metallic minerals mainly being tremolite (with minor amounts of actinolite and diopside) (relative content 38%) and talc (relative content 18%).

[0062] The raw ore sample was first crushed and ball-milled to a thickness of -0.074 mm (84%). The finely ground slurry was then poured into a flotation cell for flotation testing. The test procedure and reagent regimen are as follows: Figure 2 In this embodiment, all reagent dosages are relative to the amount added from the raw ore. The specific steps are as follows:

[0063] (1) Molybdenum pre-selection: The finely ground slurry undergoes one roughing, three scavenging, and three pre-selection processes. The roughing concentrate from the roughing process enters the pre-selection process, while the roughing tailings are scavenged to obtain pre-selected molybdenum concentrate and tailings 1. The specific reagent regimes are as follows:

[0064] First roughing: Add 300g / t of water glass and 150g / t of sodium hexametaphosphate to the grinding product at the same time, and stir for 2 minutes; then add 60g / t of butyl xanthate, and stir for 2 minutes; 30g / t of kerosene, and stir for 2 minutes; 5g / t of MIBC, and stir for 1 minute; and perform flotation and skimming for 4 minutes.

[0065] Three scavenging processes: Scavenging 1: Add 30g / t of butyl xanthate sequentially, stir for 2 min; add 20g / t of kerosene sequentially, stir for 2 min, and perform flotation and skimming for 3 min; Scavenging 2: Add 15g / t of butyl xanthate sequentially, stir for 2 min; add 10g / t of kerosene sequentially, stir for 2 min, and perform flotation and skimming for 2 min; Scavenging 3: Add 7g / t of butyl xanthate sequentially, stir for 2 min; add 5g / t of kerosene sequentially, stir for 2 min, and perform flotation and skimming for 2 min.

[0066] Three pre-selection processes: Pre-selection 1: Add 150g / t of water glass and 50g / t of sodium hexametaphosphate simultaneously, stir for 2 minutes, and perform flotation and skimming for 3 minutes; Pre-selection 2: Add 75g / t of water glass, stir for 2 minutes, and perform flotation and skimming for 2 minutes; Pre-selection 3: Blank selection, flotation and skimming for 2 minutes; Return all middlings sequentially.

[0067] (2) Planetary ball mill regrinding: The pre-selected molybdenum concentrate obtained in step (1) is regrinded to a fineness of -0.037mm accounting for 85%, and the regrinded product is obtained;

[0068] (3) Molybdenum reverse flotation (molybdenum-suppressed talc): The regrinding product obtained in step (2) undergoes a roughing, a scavenging, and a cleaning process. The roughing concentrate is then processed into the cleaning concentrate, and the roughing tailings are scavenged to obtain talc concentrate and molybdenum rough concentrate, respectively. The specific reagent system is as follows:

[0069] First roughing: Add 500g / t sodium carbonate (to pH 9.0), 100g / t sodium persulfate, stir for 2 min, 100g / t dextran, stir for 2 min, 30g / t PESA, stir for 2 min, 5g / t MIBC, stir for 1 min, and perform flotation and skimming for 3 min;

[0070] Two-stage scavenging: Scavenging 1: MIBC 5g / t, stirring for 1min, flotation and bubble scraping for 2min; Scavenging 2: MIBC 3g / t, stirring for 1min, flotation and bubble scraping for 1.5min;

[0071] Secondary purification: Purification 1: PESA 15g / t, stirring for 2min, flotation and skimming for 2.5min; Purification 2: PESA 7g / t, stirring for 2min, flotation and skimming for 2min; all middlings are returned sequentially.

[0072] (4) Molybdenum positive flotation (to improve molybdenum grade): The molybdenum rough concentrate obtained in step (3) is subjected to one roughing, two scavenging, and two cleaning processes. The rough concentrate after roughing enters the cleaning process, and the rough tailings are scavenged to obtain molybdenum concentrate and tailings 2, respectively. The specific reagent system is as follows:

[0073] First roughing: Add 70g / t of butyl xanthate and stir for 2 minutes. Then add 200g / t of water glass and 100g / t of sodium hexametaphosphate and stir for 2 minutes. Next, add 5g / t of kerosene and stir for 2 minutes. Add 5g / t of MIBC and stir for 1 minute. Perform flotation and skimming for 3 minutes.

[0074] Secondary scavenging: Scavenging 1: Add 3g / t of kerosene, stir for 2min, and skim off the bubbles for 2min; Scavenging 2: Add 2g / t of kerosene, stir for 2min, and skim off the bubbles for 2min;

[0075] Secondary refining: Refining 1: Add 100g / t of water glass and 50g / t of sodium hexametaphosphate simultaneously, stir for 2 minutes, and perform flotation and skimming for 2 minutes; Refining 2: Blank refining, flotation and skimming for 1.5 minutes; Return all middlings sequentially.

[0076] In the three flotation cycles described above, all middlings were returned sequentially. After the flotation process was executed six times and equilibrium was reached, the quality and grade of the flotation concentrate and tailings obtained in each test remained basically unchanged. Samples of the stabilized concentrate and tailings were sent for chemical analysis. The results of the closed-circuit test are shown in Table 1.

[0077] Comparative Example 1

[0078] The process flow and reagent system are basically the same as in Example 1, except that the grinding fineness of the planetary ball mill regrinding is -0.037 mm in 70% of cases, while other conditions remain unchanged. The results of the closed-circuit test are shown in Table 1.

[0079] Example 2

[0080] The process flow and reagent system are basically the same as in Example 1, except that the grinding fineness of the planetary ball mill regrinding is -0.037 mm in 80% of cases, while other conditions remain unchanged. The results of the closed-circuit test are shown in Table 1.

[0081] Example 3

[0082] The process flow and reagent system are basically the same as in Example 1, except that the grinding fineness of the planetary ball mill regrinding is -0.037 mm in 95% of cases, while other conditions remain unchanged. The results of the closed-circuit test are shown in Table 1.

[0083] Comparative Example 2

[0084] The process flow and reagent system are basically the same as in Example 1, except that the planetary ball mill regrinding is replaced with ordinary ball mill regrinding, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0085] Comparative Example 3

[0086] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added in the roughing stage of the molybdenum reverse flotation process is replaced with sodium persulfate 230g / t, and dextran and PESA are not added, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0087] Comparative Example 4

[0088] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added in the roughing stage of the molybdenum reverse flotation is replaced with dextran 230g / t, and sodium persulfate and PESA are not added, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0089] Comparative Example 5

[0090] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added in the roughing stage of the molybdenum reverse flotation is replaced with PESA 230 g / t, and sodium persulfate and dextran are not added, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0091] Comparative Example 6

[0092] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added in the roughing stage of the molybdenum reverse flotation process is replaced with sodium persulfate 100g / t + dextran 130g / t, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0093] Comparative Example 7

[0094] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added in the roughing stage of the molybdenum reverse flotation process is replaced with sodium persulfate 100g / t + PESA 130g / t, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0095] Example 4

[0096] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added during the roughing stage of the molybdenum reverse flotation is replaced with sodium persulfate 50g / t + dextran 50g / t + PESA 50g / t, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0097] Example 5

[0098] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added during the roughing stage of the molybdenum reverse flotation is replaced with sodium persulfate 200g / t + dextran 100g / t + PESA 100g / t, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0099] Example 6

[0100] The process flow is basically the same as in Example 1, except that the sodium persulfate 100g / t + dextran 100g / t + PESA 30g / t added during the roughing stage of the molybdenum reverse flotation is replaced with sodium persulfate 300g / t + dextran 150g / t + PESA 150g / t, while other conditions remain unchanged. The closed-circuit test results are shown in Table 1.

[0101] Comparative Example 8

[0102] The raw ore in this embodiment is the same as in Example 1, with the same grinding fineness of -74μm (84%). The separation of molybdenite and talc uses the following process: "Talc removal from raw ore—molybdenum pre-selection—ordinary ball milling and regrinding—molybdenum and talc positive flotation separation". All reagent dosages in this embodiment are relative to the amount added from the raw ore. The specific process steps are as follows:

[0103] 1) Talc removal: After grinding the raw ore, two-stage desliming is carried out. First stage desliming: MIBC 8g / t, stirring for 2min, flotation for 3min; Second stage desliming: MIBC 8g / t, stirring for 2min, flotation for 3min; The concentrates from the two stages of desliming are combined into desliming product (discarded);

[0104] 2) Molybdenum Pre-selection: The deslimed tailings undergo one roughing, three scavenging, and three pre-selection processes to obtain pre-selected molybdenum concentrate and tailings 1. The specific details of the one roughing, three scavenging, and three pre-selection processes are as follows:

[0105] First roughing: Add 300g / t of water glass and 150g / t of sodium hexametaphosphate to the grinding product at the same time, and stir for 2 minutes; then add 60g / t of butyl xanthate, and stir for 2 minutes; 30g / t of kerosene, and stir for 2 minutes; 5g / t of MIBC, and stir for 1 minute; and perform flotation and skimming for 4 minutes.

[0106] Three scavenging processes: Scavenging 1: Add 30g / t of butyl xanthate sequentially, stir for 2 min; add 20g / t of kerosene, stir for 2 min, and perform flotation and skimming for 3 min; Scavenging 2: Add 15g / t of butyl xanthate sequentially, stir for 2 min; add 10g / t of kerosene, stir for 2 min, and perform flotation and skimming for 2 min; Scavenging 3: Add 10g / t of butyl xanthate sequentially, stir for 2 min; add 5g / t of kerosene, stir for 2 min, and perform flotation and skimming for 2 min.

[0107] Three pre-selection processes: Pre-selection 1: Add 150g / t of water glass and 50g / t of sodium hexametaphosphate simultaneously, stir for 2 minutes, and perform flotation and skimming for 3 minutes; Pre-selection 2: Add 75g / t of water glass, stir for 2 minutes, and perform flotation and skimming for 2 minutes; Pre-selection 3: Blank selection, flotation and skimming for 2 minutes; Return all middlings sequentially.

[0108] 3) Ball milling and regrinding: The pre-selected molybdenum concentrate is regrinded by ordinary ball milling to a fineness of -0.037mm accounting for 85%, and the regrinded pre-selected molybdenum concentrate is obtained.

[0109] 4) Molybdenum and talc separation by direct flotation: The regrinded pre-selected molybdenum concentrate undergoes one roughing, three scavenging, and four cleaning processes to obtain molybdenum concentrate and tailings 2. The specific steps of the one roughing, three scavenging, and four cleaning processes are as follows:

[0110] First roughing: Add 150g / t of sodium sulfite and stir for 2 min; add 100g / t of water glass and 2g / t of carboxymethyl cellulose and stir for 2 min; add 100g / t of mercaptoacetic acid and stir for 2 min; add 7g / t of kerosene and stir for 2 min; add 2g / t of MIBC and stir for 1 min; then perform flotation and skim frothing for 2.5 min.

[0111] Three scavenging processes: Scavenging 1: kerosene 5g / t, stirring for 2min, flotation skimming for 1.5min; Scavenging 2: kerosene 5g / t, stirring for 2min, flotation skimming for 1.5min; Scavenging 3: kerosene 3g / t, stirring for 2min, MIBC 2g / t, flotation skimming for 1.5min.

[0112] Four refining processes: Refining 1: Add 50 g / t of sodium sulfite sequentially, stir for 2 min; add 30 g / t of water glass and 0.5 g / t of carboxymethyl cellulose sequentially, stir for 2 min, and perform flotation skimming for 5 min; Refining 2: Add 0.5 g / t of carboxymethyl cellulose sequentially, stir for 2 min; add 2 g / t of MIBC sequentially, stir for 2 min, and perform flotation skimming for 4 min; Refining 3: Add 0.2 g / t of carboxymethyl cellulose sequentially, stir for 2 min, and perform flotation skimming for 4 min; Refining 4: Blank refining, flotation skimming for 4 min; all middlings are returned sequentially. Closed-circuit test results are shown in Table 1.

[0113] Table 1. Closed-circuit test results of Examples 1-6 and Comparative Examples 1-8 / %

[0114]

[0115]

[0116]

[0117] A comparison of Examples 1-3 (re-grinding fineness of -0.037 mm accounting for 85%, 80%, and 95%, respectively) with Comparative Example 1 (re-grinding fineness of -0.037 mm accounting for 70%) shows that when the planetary ball mill retrinding fineness is 80-95%, the molybdenum grade in the obtained molybdenum concentrate is 50.96%-51.12%, and the molybdenum recovery rate is 73.38%-78.97%. When the planetary ball mill retrinding fineness is too coarse, with -0.037 mm accounting for 70%, the exposed amount of the hydrophilic and easily oxidized end face of molybdenite is insufficient. This results in insufficient synergistic regulation of the hydrophilicity of the molybdenite surface by oxidants and inhibitors in the molybdenum-talc reverse flotation operation. Consequently, some molybdenite floats to the surface with the talc, and the molybdenum loss rate in the talc concentrate increases significantly to 15.05%. Compared to Example 1, in Example 3, when the regrinding fineness increased to 95% (-0.037 mm), both the molybdenum grade and recovery rate in the molybdenum concentrate decreased. This indicates that at this grinding fineness, the molybdenite particle size was too fine, making it difficult to suppress. The fine particles also floated to the talc concentrate with the talc, increasing the molybdenum loss rate in the talc concentrate from 0.85% to 4.78%. This demonstrates that both excessively coarse and excessively fine grinding fineness in planetary mills are detrimental to molybdenum enrichment and recovery. Comparative Example 2 shows that, compared to Example 1, using a conventional ball mill for regrinding, with the same regrinding fineness of 85% (-0.037 mm), the molybdenum suppression effect in the reverse flotation operation was poor, resulting in a molybdenum loss rate as high as 50.73% in the talc concentrate. Sodium persulfate alone (Comparative Example 3) and PESA alone (Comparative Example 5) as depressants had weak inhibitory effects on molybdenite, with molybdenum loss rates in the talc concentrate reaching 30.25% and 35.70%, respectively. Using dextran alone (Comparative Example 4) as a collector, excessive dosage inhibited the separation of both talc and molybdenite, resulting in a large amount of talc being trapped in the molybdenum concentrate, with a molybdenum grade of only 1.12%. The combination of sodium persulfate and dextran (Comparative Example 6) or sodium persulfate and PESA (Comparative Example 7) showed poor selective separation of molybdenite and talc, with molybdenum losses of 34.31% and 28.68% in the talc concentrate, respectively, and low molybdenum concentrate grades of 22.58% and 19.08%, respectively. The comparative analysis of these results indicates that, using the new process proposed in this invention, the grinding method (planetary ball mill) and grinding fineness in the grinding operation, as well as the synergistic effect of the oxidant (sodium persulfate) and inhibitor (dextran / PESA) in the flotation operation, are crucial. Under optimal conditions, the separation effect of high-talc molybdenum ore is the best.In Examples 1 and 4-6, the primary roughing stage of the molybdenum reverse flotation process used a combination of sodium persulfate, dextran, and PESA. The dosage of sodium persulfate was 50-300 g / t, the dosage of dextran was 50-300 g / t, and the dosage of PESA was 25-150 g / t, with a weight ratio of (3-1):1:(2-0.2). The resulting molybdenum concentrate had a molybdenum grade of 50.05%-51.22% (all greater than 50%), and a molybdenum recovery rate of 72.07%-79.18% (all greater than 72%). This indicates that appropriate dosages of oxidant and depressant can effectively and selectively inhibit molybdenite. Within this range, low dosages of oxidant and depressant resulted in weak molybdenum inhibition, leading to a high molybdenum content lost in the talc concentrate. Conversely, excessively high dosages of oxidant and depressant resulted in stronger molybdenum inhibition, leading to a lower molybdenum concentrate recovery rate. The above demonstrates that the appropriate type and dosage of oxidants and inhibitors play a crucial role in the selective separation of talc and molybdenite. Using a conventional positive flotation separation process for molybdenum using talc inhibitors (Comparative Example 8), the molybdenum loss rate in the desliming product was 5.16%, the molybdenum grade in the molybdenum concentrate was 43.34%, and the molybdenum recovery rate was 69.90%. Compared to the new flotation process of this invention (Example 1), the new process resulted in a 7.78% increase in molybdenum grade and a 9.07% increase in molybdenum recovery rate in the obtained molybdenum concentrate. This indicates that for the flotation separation of high-talc molybdenum ores, the new beneficiation method proposed in this invention can significantly improve molybdenum separation indicators and obtain qualified molybdenum concentrate products.

[0118] Example 7

[0119] The molybdenite / talc mixed concentrate was obtained from the tailings after talc removal at a high-talc molybdenum mine beneficiation plant in Henan Province. This was the frothy product (thickening mill bottom flow) of molybdenum flotation (one roughing, three scavenging, and two pre-cleaning processes). Because talc is prone to mud formation, it severely interferes with molybdenite flotation through mud covering and mechanical entrainment. The beneficiation plant first removed some talc through pre-desliming, then enriched molybdenum through molybdenum flotation circulation to obtain a pre-concentrated molybdenum concentrate (molybdenite / talc mixed concentrate). The Mo recovery rate in this pre-concentrated molybdenum concentrate was 82%. The mixed concentrate contained 15.96% Mo and 10.07% MgO. The gangue mainly consisted of talc and tremolite, with minor amounts of dolomite, calcite, mica, and other gangues. The concentrated molybdenum pre-concentrated concentrate (hereinafter referred to as "feed") was regrinded using a planetary ball mill to a fineness of -0.037 mm (82%). Flotation separation tests were then conducted, and the test procedure is as follows: Figure 4 In this embodiment, all reagent dosages are relative to the amount added to the molybdenum pre-selected concentrate (a mixed concentrate of molybdenite / talc, hereinafter referred to as "feed"). The specific steps are as follows:

[0120] (1) Molybdenum reverse flotation (molybdenum-suppressed talc): The regrinded product undergoes a first roughing, a second scavenging, and a second cleaning process to obtain talc concentrate and molybdenum rough concentrate, respectively. The process flow and reagent system for the first roughing, second scavenging, and second cleaning process are as follows:

[0121] First roughing: Add 1000 g / t Na2CO3 (to pH 9.5), 1000 g / t sodium persulfate, stir for 2 min, add 600 g / t dextran, stir for 2 min, add 150 g / t PESA (to feed), stir for 2 min, add 49 g / t MIBC, stir for 1 min, and perform flotation skimming for 5 min;

[0122] Secondary scavenging: Scavenging 1: Add 28g / t of MIBC, stir for 1min, and perform flotation and bubble scraping for 2.5min; Scavenging 2: Add 14g / t of MIBC, stir for 1min, and perform flotation and bubble scraping for 2min;

[0123] Secondary refining: Refining 1: Add 90 g / t of PESA, stir for 2 min, and perform flotation and skimming for 2.5 min; Refining 2: Add 45 g / t of PESA, stir for 2 min, and perform flotation and skimming for 2 min; Return all middlings sequentially.

[0124] (2) Molybdenum positive flotation (to improve molybdenum grade): The molybdenum rough concentrate undergoes a first roughing, a second scavenging, and a second cleaning process to obtain molybdenum concentrate and tailings 2. The process flow and reagent system for the first roughing, second scavenging, and second cleaning process are as follows:

[0125] First roughing: Add 300g / t of butyl xanthate and stir for 2 min; then simultaneously add 800g / t of water glass and 400g / t of sodium hexametaphosphate and stir for 2 min; 20g / t of kerosene and stir for 2 min; 21g / t of MIBC and stir for 1 min; flotation and skimming for 3.5 min.

[0126] Two scavenging processes: Scavenging 1: Add 14g / t of kerosene, stir for 2 minutes, and skim off bubbles for 2 minutes; Scavenging 2: Add 7g / t of kerosene, stir for 2 minutes, and skim off bubbles for 1.5 minutes.

[0127] Two fine selection processes: Fine selection 1: Add 400g / t of water glass and 200g / t of sodium hexametaphosphate simultaneously, stir for 2 minutes, and perform flotation and bubble scraping for 2.5 minutes; Fine selection 2: Add 200g / t of water glass, stir for 2 minutes, and perform flotation and bubble scraping for 1.5 minutes.

[0128] In the three flotation cycles described above, all middlings were returned sequentially. After the flotation process was executed six times and equilibrium was reached, the quality and grade of the flotation concentrate and tailings obtained in each test remained basically unchanged. Samples of the stabilized concentrate and tailings were sent for chemical analysis. The results of the closed-circuit test are shown in Table 2.

[0129] Comparative Example 9

[0130] The concentrated molybdenite and talc mixed concentrate (same as in Example 7) was regrinded using a conventional ball mill to achieve a regrinding fineness of -0.037 mm (82%). The regrinded product was then separated using a positive flotation process, employing a process flow of one roughing, three scavenging, and four cleaning stages. All reagent dosages in this comparative example refer to the addition amounts of the pre-cleaned molybdenum concentrate (molybdenite / talc mixed concentrate). The one roughing, three scavenging, and four cleaning stages are as follows:

[0131] First roughing: Add 200g / t of sodium metabisulfite and stir for 2 min; add 150g / t of water glass and 3g / t of carboxymethyl cellulose and stir for 2 min; add 7g / t of kerosene and stir for 2 min; add 4g / t of MIBC and stir for 1 min; then perform flotation and skim-over for 3 min.

[0132] Three scavenging processes: Scavenging 1: Add 6g / t of kerosene, stir for 2min, and skim off bubbles for 2min; Scavenging 2: Add 3g / t of kerosene, stir for 2min, and skim off bubbles for 2min; Scavenging 3: Add 2g / t of kerosene, stir for 2min, add 2g / t of MIBC, and skim off bubbles for 1.5min.

[0133] Four refining processes: Refining 1: Add 100g / t of sodium metabisulfite and stir for 2 min; then add 50g / t of water glass and 1g / t of carboxymethyl cellulose, stir for 2 min, and perform flotation and bubble scraping for 4.5 min; Refining 2: Add 1g / t of carboxymethyl cellulose in sequence, stir for 2 min, then add 2g / t of MIBC, stir for 2 min, and perform flotation and bubble scraping for 4 min; Refining 3: Add 0.5g / t of carboxymethyl cellulose, stir for 2 min, and perform flotation and bubble scraping for 4 min; Refining 4: Blank refining, and perform flotation and bubble scraping for 3.5 min.

[0134] The results of the closed-circuit test are shown in Table 2.

[0135] Table 2 Closed-circuit test results of Example 7 and Comparative Example 9 / %

[0136]

[0137] As shown in Table 2, for the flotation separation of molybdenum pre-selected concentrate, the new process "mixed concentrate planetary ball milling and regrinding—molybdenum reverse flotation (molybdenum suppression and talc flotation)—molybdenum forward flotation (improving molybdenum grade)" was adopted. In the reverse flotation operation, sodium persulfate was added as an oxidant, and dextran + PESA as an inhibitor to synergistically suppress molybdenite (Example 7). This resulted in a molybdenum grade of 50.88% in the molybdenum concentrate, a molybdenum recovery rate of 93.20%, and a total molybdenum recovery rate of 76.42%. In contrast, the conventional flotation process using talc to suppress molybdenite (Comparative Example 9) resulted in a molybdenum grade of only 42.25% in the molybdenum concentrate, a molybdenum recovery rate of 64.62%, and a total molybdenum recovery rate of 52.99%. The new process increased the molybdenum grade by 8.63% and the total molybdenum recovery rate by 23.43%. Regarding the recovery of molybdenum pre-selected concentrate (molybdenite / talc mixed concentrate), this demonstrates that the new separation method of this invention can significantly improve molybdenum separation indicators and obtain qualified molybdenum concentrate products.

Claims

1. A method for separating high-talc molybdenum ore, comprising the following steps: (1) grinding the raw ore: after crushing the raw ore, wet ball milling is performed to obtain ore slurry 1; (2) molybdenum pre-separation: water glass + sodium hexametaphosphate, butyl xanthate, kerosene, MIBC are sequentially added to the ore slurry 1 for molybdenum pre-separation to obtain pre-separation molybdenum concentrate and tailings 1; (3) planetary ball milling regrinding: the pre-separation molybdenum concentrate obtained in step (2) is regrinded by planetary ball milling to obtain ore slurry 2, and the regrinding fineness is 80% to 95% of -0.037 mm; (4) molybdenum reverse flotation: sodium carbonate is added to the ore slurry 2 to adjust the pH value of the ore slurry to a set range, and then sodium persulfate, dextran, PESA and MIBC are sequentially added for molybdenum reverse flotation to obtain talc concentrate and molybdenum rough concentrate, and the mass ratio of sodium persulfate, dextran and PESA is (3-1) : 1 : (2-0.2) ; (5) molybdenum direct flotation: butyl xanthate, water glass + sodium hexametaphosphate and kerosene are sequentially added to the molybdenum rough concentrate obtained in step (4) for molybdenum direct flotation to obtain molybdenum concentrate and tailings 2; The PESA has a molecular formula of HO(C4R2O5M2) n H, with a relative molecular mass of 400-1500 and a structural formula of: ； wherein n = 2-10, M is Na + , H + or NH4 + , R is H or C 14 alkyl.

2. The method of claim 1, wherein, In step (1), the grinding fineness of the raw ore is 75% to 90% of -0.074 mm.

3. The method of claim 1 wherein, In step (2), the process flow of the molybdenum pre-separation is one roughing, three scavenging and three pre-concentration, and the roughing concentrate after roughing is subjected to pre-concentration, and the tailings after roughing are subjected to scavenging.

4. The sorting method according to claim 1 or 3, characterized in that, The specific process flow and reagent system of the molybdenum pre-separation are as follows: Roughing: water glass 300-2000 g / t + sodium hexametaphosphate 100-2000 g / t are simultaneously added to the ore slurry 1, stirring for 2-3 min, and the mass ratio of water glass to sodium hexametaphosphate is (3-2) : 1; then butyl xanthate 50-600 g / t is added, stirring for 2-3 min; kerosene 25-200 g / t is added, stirring for 2-3 min; MIBC 0-100 g / t is added, stirring for 1-2 min, and the froth is scraped for 3-6 min; Scavenging 1: butyl xanthate 25-300 g / t is added, stirring for 2-3 min; kerosene 13-100 g / t is added, stirring for 2-3 min, and the froth is scraped for 1-5 min; Scavenging 2: butyl xanthate 12-150 g / t is added, stirring for 2-3 min; kerosene 7-50 g / t is added, stirring for 2-3 min, and the froth is scraped for 1-5 min; Scavenging 3: butyl xanthate 6-75 g / t is added, stirring for 2-3 min; kerosene 3-25 g / t is added, stirring for 2-3 min, and the froth is scraped for 1-5 min; Pre-concentration 1: water glass 150-1000 g / t + sodium hexametaphosphate 50-1000 g / t are simultaneously added, stirring for 2-3 min, and the froth is scraped for 2-5 min, and the mass ratio of water glass to sodium hexametaphosphate is (3-2) : 1; Pre-concentration 2: water glass 75-500 g / t is added, stirring for 2-3 min, and the froth is scraped for 1-5 min; Pre-concentration 3: blank concentration, and the froth is scraped for 1-5 min.

5. The method of claim 1 wherein, In step (4), the pH value of the ore slurry is adjusted to 8.0-9.5 by sodium carbonate.

6. The method of claim 1 wherein, In step (4), the process flow of the molybdenum reverse flotation is once roughing, twice scavenging and twice cleaning, the roughing concentrate after roughing enters cleaning, and the roughing tailings enter scavenging; the specific process flow and reagent system of the molybdenum reverse flotation are as follows: Roughing: adding sodium carbonate to adjust the pH of the ore pulp to 8.0-9.5, then adding sodium persulfate 50-300 g / t in turn, stirring for 2-3 min, adding dextran 50-300 g / t, stirring for 2-3 min, adding PESA 25-150 g / t, stirring for 2-3 min, adding MIBC 0-30 g / t, stirring for 1-2 min, and floating for 3-6 min, wherein the mass ratio of the three reagents of sodium persulfate, dextran and PESA is (3-1):1:(2-0.2); Scavenging I: adding MIBC 0-15 g / t, stirring for 1-2 min, and floating for 1-4 min; Scavenging II: adding MIBC 0-7 g / t, stirring for 1-2 min, and floating for 1-3 min; Cleaning I: adding PESA 12-75 g / t, stirring for 2-3 min, and floating for 2-3 min; Cleaning II: adding PESA 6-35 g / t, stirring for 2-3 min, and floating for 1-3 min.

7. The method of claim 1 wherein, In step (5), the process flow of the molybdenum direct flotation is once roughing, twice scavenging and twice cleaning, the roughing concentrate after roughing enters cleaning, and the roughing tailings enter scavenging.

8. The method of claim 1 or 7, wherein, In step (5), the specific process flow and reagent system of the molybdenum direct flotation are as follows: Roughing: adding butyl xanthate 50-500 g / t first, stirring for 2-3 min, then adding water glass 200-1000 g / t+hexametaphosphate 100-1000 g / t at the same time, stirring for 2-3 min, then adding kerosene 3-100 g / t in turn, stirring for 2-3 min, adding MIBC 0-100 g / t, stirring for 1-2 min, and floating for 1-5 min; wherein the mass ratio of water glass to hexametaphosphate is (3-2):1; Scavenging I: adding kerosene 1-50 g / t, stirring for 2-3 min, and floating for 1-3 min; Scavenging II: adding kerosene 1-25 g / t, stirring for 2-3 min, and floating for 1-3 min; Cleaning I: adding water glass 100-500 g / t+hexametaphosphate 50-500 g / t at the same time, stirring for 2-3 min, and floating for 1-3 min; wherein the mass ratio of water glass to hexametaphosphate is (3-2):1; Cleaning II: water glass 0-250 g / t+hexametaphosphate 0-250 g / t, stirring for 2-3 min, and floating for 1-2 min.

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