Method for extracting molybdenum concentrate powder from molybdenum concentrate through flotation

Abstract

The invention discloses a method for extracting molybdenum concentrate powder through molybdenum concentrate flotation, and belongs to the technical field of beneficiation. The method comprises the following steps that S1, molybdenum concentrate and retreated flotation middling are mixed to be subjected to interlayer shear intensified dissociation treatment, and dissociated ore pulp is obtained; the high-shear stirring mill adopts an ore grinding medium made of zirconia ceramic or Al2O3, the diameter phi of the ore grinding medium is 3-5 mm, the linear speed is 15-20 m / s, and sodium dodecyl sulfate is added; s2, water is added into the dissociated ore pulp for pulp mixing, selective hydrophobic agglomeration flotation is conducted, and roughing foam and flotation middlings are obtained; s3, the roughing foam is fed into a stepped foam tank with the dip angle ranging from 25 degrees to 30 degrees to be subjected to foam enrichment and copper inhibition treatment, and molybdenum concentrate powder is obtained; and S4, the flotation middlings are returned to the step S1 to be mixed with the molybdenum concentrate for retreatment. According to the method, through the synergistic effect of high-shear directional dissociation and stepped foam copper enrichment inhibition, the molybdenum recovery rate and the concentrate quality are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a method for extracting molybdenum concentrate powder by flotation of molybdenum concentrate. Background Technology

[0002] In molybdenum ore beneficiation, especially when processing veinlet-disseminated molybdenum ore, mixed flotation is often used to obtain a rough concentrate, which is then further improved through regrinding and re-concentration processes. Existing technologies (such as CN102205270A) attempt to optimize the process by adding a fine screen (55-80 mesh) to the return sand inlet of the hydrocyclone to pre-separate coarse molybdenum concentrate. However, this technology has significant drawbacks: the fine screening process leads to a large amount of -200 mesh fine molybdenum particles being over-crushed and difficult to float effectively, resulting in the loss of molybdenum metal; simultaneously, the material returned for regrinding often contains incompletely liberated molybdenum-copper intergrowths, causing this valuable molybdenum mineral to circulate ineffectively within the system.

[0003] Looking deeper, existing processes generally face several key technical challenges when processing such ores. First, due to their layered structure, fine-veined molybdenum minerals (such as molybdenite) are difficult to fully and selectively liberate using conventional grinding, affecting subsequent separation efficiency. Second, the fine-grained (-20μm) molybdenum minerals commonly found in the ore, due to their small mass and large specific surface area, are difficult to effectively adhere to bubbles during conventional flotation, resulting in low flotation recovery rates. Third, while coarse-grained (+100 mesh) molybdenum minerals have better floatability, they are easily detached from bubbles in the turbulent environment of the flotation cell, also causing recovery losses. Furthermore, associated copper minerals in the ore are difficult to selectively suppress, leading to a high copper impurity content in the final molybdenum concentrate (e.g., copper content in coarse-grained concentrate often exceeds 0.6%), affecting concentrate quality.

[0004] The aforementioned problems are interconnected and collectively constrain the improvement of technical and economic indicators in molybdenum beneficiation. Issues such as fine-grained molybdenum loss, intergrowth recycling, coarse-grained detachment, and the difficulty in effectively suppressing copper minerals not only reduce the overall molybdenum recovery rate but also make it difficult for the final concentrate grade to meet high-quality requirements. Therefore, there is an urgent need to develop more effective technical solutions to address these comprehensive technical bottlenecks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for extracting molybdenum concentrate from molybdenum concentrate by flotation, comprising the following steps: S1, mixing the molybdenum concentrate and reprocessed flotation concentrate and feeding them into a high-shear stirred mill for interlayer shear-enhanced liberation treatment to obtain a liberated slurry; the high-shear stirred mill uses grinding media made of zirconia ceramic or Al2O3 material, with a grinding media diameter of Φ3-5 mm, a linear velocity of 15-20 m / s, and adding 0.2-0.5 kg / t of sodium dodecyl sulfonate to the raw ore; S2, adding water to the liberated slurry to adjust the concentration to 25-35 wt% and feeding it into a low-turbulence flotation machine for selective hydrophobic agglomeration flotation to obtain rougher froth and flotation concentrate; S3, feeding the rougher froth into a stepped froth tank with an inclination angle of 25°-30° for froth enrichment and copper suppression treatment to obtain molybdenum concentrate; S4, returning the flotation concentrate to step S1 and mixing it with the molybdenum concentrate for reprocessing.

[0006] In some embodiments, a composite agglomerating agent is added in step S2, the composite agglomerating agent comprising 0.1-0.3 kg / t of polyisobutylene succinimide and 0.05 kg / t of sodium dimethyl dithiocarbamate.

[0007] In some embodiments, step S2 specifically includes: S21, adding 0.1-0.3 kg / t of polyisobutylene succinimide to the dissociated slurry and stirring for 5-8 minutes; S22, continuing to add 0.05 kg / t of sodium dimethyl dithiocarbamate to the slurry and stirring for 3-5 minutes to form an agglomerated slurry; S23, feeding the agglomerated slurry into a low-turbulence flotation machine for flotation.

[0008] In some embodiments, the thickness of the foam layer in the stepped foam groove in step S3 is controlled to be ≥15 cm.

[0009] In some embodiments, the thickness of the foam layer in the stepped foam tank is controlled to be 18-25 cm by adjusting the height of the tailings gate.

[0010] In some embodiments, a copper inhibitor is added in step S3. The copper inhibitor is composed of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, and the total dosage is 0.3-0.5 kg / t of raw ore.

[0011] In some embodiments, the copper inhibitor is added in two stages to the stepped foam tank, with 60% of the total mass added at the bottom of the foam layer and the remaining 40% added in the middle of the foam layer.

[0012] In some embodiments, the impeller speed of the low-turbulence flotation machine in step S2 is ≤200 rpm.

[0013] In some embodiments, the grinding media in step S1 are zirconia ceramic balls.

[0014] In some embodiments, the ore returned for reprocessing in step S4 accounts for 15-30 wt% of the total ore feed in step S1.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Interlayer shear enhancement and dissociation treatment is carried out by high-shear stirred mill. The grinding media is made of zirconia ceramic or Al2O3 material, with a diameter of Φ3-5 mm and a linear velocity of 15-20 m / s. Sodium dodecyl sulfonate of 0.2-0.5 kg / t of raw ore is added to ensure sufficient dissociation of fine vein-embedded molybdenum and avoid loss of fine-grained molybdenum and over-grinding.

[0016] 2. Selective hydrophobic agglomeration flotation is carried out using a low-turbulence flotation machine with an impeller speed of ≤200 rpm, which improves the flotation efficiency of fine molybdenum particles and reduces the shedding of coarse molybdenum particles.

[0017] 3. Foam enrichment and copper suppression are carried out through stepped foam tanks with an inclination angle of 25°-30° and a foam layer thickness of ≥15 cm, which makes coarse molybdenum stably enriched and copper minerals selectively suppressed.

[0018] 4. By returning the ore from flotation to a high-shear stirred mill for reprocessing, the intergrown material is recovered, thereby improving the overall molybdenum recovery rate.

[0019] 5. By adding a composite agglomerating agent containing 0.1-0.3 kg / t of polyisobutylene succinimide and 0.05 kg / t of sodium dimethyl dithiocarbamate, the fine molybdenum particles form hydrophobic agglomerates, thereby improving flotation efficiency.

[0020] 6. By controlling the thickness of the foam layer in the stepped foam tank to ≥15 cm, the foam layer is stabilized, reducing the shedding of coarse molybdenum particles.

[0021] 7. By adding a copper inhibitor composed of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, with a total dosage of 0.3-0.5 kg / t of raw ore, the copper impurity content is reduced, thereby improving the purity of molybdenum concentrate.

[0022] 8. By adding the copper inhibitor in two stages, 60% of the total mass is added to the bottom of the foam layer and the remaining 40% to the middle of the foam layer, the copper inhibition is more uniform and thorough, reducing the mixing of copper minerals.

[0023] 9. By using zirconia ceramic balls as grinding media, the dissociation efficiency is improved, and undissociated molybdenum-copper intergrowths are reduced. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] This specification provides one or more embodiments of a method for extracting molybdenum concentrate from molybdenum concentrate by flotation, comprising the following steps: S1. The molybdenum concentrate and the reprocessed flotation ore are mixed and fed into a high-shear stirred mill for interlayer shear-enhanced liberation treatment to obtain a liberated slurry. The high-shear stirred mill uses grinding media made of zirconium oxide ceramic or Al2O3 material, with a grinding media diameter of Φ3-5 mm, a linear velocity of 15-20 m / s, and 0.2-0.5 kg / t of sodium dodecyl sulfonate is added. S2. After adding water to adjust the concentration of the liberated slurry to 25-35wt%, it is sent to a low-turbulence flotation machine for selective hydrophobic agglomeration flotation to obtain rougher froth and flotation medium ore. S3. The coarsely selected foam is fed into a stepped foam tank with an inclination angle of 25°-30° for foam enrichment and copper suppression treatment to obtain molybdenum concentrate. S4. Return the ore from the flotation process to step S1 and mix it with the molybdenum concentrate for further processing.

[0026] In the method for extracting molybdenum concentrate from molybdenum concentrate by flotation, the molybdenum concentrate and the reprocessed flotation ore are first fed into a high-shear stirred mill for interlayer shear-enhanced liberation treatment. Here, the reprocessed flotation ore is provided by the flotation ore produced in step S4 of the previous process cycle. The high-shear stirred mill uses grinding media made of zirconia ceramic or Al2O3 material with a diameter of Φ3-5 mm and operates at a linear velocity of 15-20 m / s, while sodium dodecyl sulfate (0.2-0.5 kg / t of raw ore) is added. The working principle of this step is to use high shear force to directionally act on the layered structure of molybdenum minerals (such as molybdenite), generating strong mechanical shear. Combined with the adsorption effect of sodium dodecyl sulfate, this additive can penetrate into the interlayer of minerals, weakening the interlayer van der Waals forces, thereby achieving selective liberation. This solves the problem of insufficient liberation of fine vein-embedded molybdenum, because conventional grinding easily leads to over-grinding or insufficient liberation, while high shear force can precisely strip the mineral layers, avoiding the loss of fine-grained molybdenum and ensuring that mineral particles are fully liberated without compromising their floatability.

[0027] Next, the liberated slurry is adjusted to a concentration of 25-35 wt% with water and then fed into a low-turbulence flotation machine for selective hydrophobic agglomeration flotation. The impeller speed of the low-turbulence flotation machine is controlled at a low level to minimize turbulence intensity, creating a stable environment for the flotation process. The working principle of selective hydrophobic agglomeration flotation is that, under low-turbulence conditions, fine-grained molybdenum minerals (such as -20μm particles) spontaneously agglomerate through hydrophobic interactions to form larger agglomerates, increasing their mass and size, thus making them easier to adhere to bubbles. At the same time, the low-turbulence environment reduces the impact on coarse-grained molybdenum (such as +100 mesh particles), preventing them from falling off the bubbles. This directly solves the problems of low flotation efficiency for fine-grained molybdenum and high detachment rate for coarse-grained molybdenum, because with reduced turbulence, bubble-mineral adhesion is more stable, the agglomeration mechanism improves the flotation recovery rate of fine particles, and coarse-grained minerals are less likely to detach in a calm environment, thus improving overall flotation efficiency.

[0028] Then, the coarsely selected foam is fed into a stepped foam tank with an inclination angle of 25°-30° for foam enrichment and copper suppression. The inclined design of the stepped foam tank allows the foam layer to flow and enrich naturally under gravity, while the 25°-30° inclination angle optimizes the foam's movement speed, ensuring that coarse molybdenum minerals remain stably in the foam layer and are not easily detached. Simultaneously, the copper suppression treatment reduces the floatability of copper minerals through a chemical inhibition mechanism. The working principle of this step is that the inclined foam layer reduces the turbulence of mineral particles, promoting the enrichment of molybdenum minerals in the foam, while the copper inhibitor selectively acts on the surface of copper minerals, inhibiting their flotation, thereby improving the purity of the molybdenum concentrate. This solves the problems of high coarse molybdenum detachment rate and difficulty in selectively suppressing copper minerals, because the stable flow of the foam layer prevents coarse particle loss, and the copper suppression mechanism effectively separates impurities, ensuring the final quality of the molybdenum concentrate.

[0029] Finally, the middlings from flotation are returned to the high-shear stirred mill for reprocessing. The working principle of middlings reprocessing is to recycle insufficiently liberated or unfloated minerals back to the liberation step, utilizing the interlayer strengthening mechanism of the high-shear stirred mill for reprocessing. This ensures the complete recovery of intergrowths or residual molybdenum minerals. This step solves the problem of intergrowth recycling in the ore because recycling avoids the ineffective retention of valuable minerals in the system, improving the overall recovery rate. Simultaneously, by repeatedly liberating and optimizing the degree of mineral liberation, the entire process forms a closed loop, maximizing resource utilization. The entire process is logically coherent, progressively optimizing the extraction efficiency and quality of molybdenum concentrate from liberation to flotation, copper enrichment and suppression, and finally, middlings recycling.

[0030] In some embodiments, a composite agglomerating agent is added in step S2, the composite agglomerating agent comprising 0.1-0.3 kg / t of polyisobutylene succinimide and 0.05 kg / t of sodium dimethyl dithiocarbamate.

[0031] In the selective hydrophobic agglomeration flotation stage, the addition of composite agglomerants is a key measure to address the low flotation efficiency of fine-grained molybdenum minerals (-20 μm). Due to their extremely small particle size, light weight, and large specific surface area, fine-grained molybdenum particles are difficult to adhere effectively to air bubbles during flotation, leading to a significant reduction in recovery rate. The introduction of composite agglomerants promotes the agglomeration of fine particles through physicochemical mechanisms, increasing their size and mass, thereby optimizing flotation behavior.

[0032] The composite agglomerator contains polyisobutylene succinimide and sodium dimethyl dithiocarbamate. Polyisobutylene succinimide selectively adsorbs onto the surface of molybdenum minerals through its hydrophobic groups, forming a stable hydrophobic film and reducing the surface energy of the minerals. At the same time, the bridging effect of this component promotes the agglomeration of adjacent fine molybdenum mineral particles through van der Waals forces and hydrophobic attraction, forming larger hydrophobic agglomerates with a size of 50-100 micrometers. This directly increases the effective diameter and mass of the particles, making them easier to overcome inertial resistance in the flotation environment.

[0033] Sodium dimethyl dithiocarbamate, as an auxiliary component, synergistically enhances the agglomeration effect. The thiocarbamate groups in its molecular structure further strengthen the hydrophobicity of the mineral surface and reduce electrostatic repulsion between particles through charge regulation, ensuring that the agglomerates remain stable in the slurry and are not easily dispersed. This synergistic effect is fully utilized in the calm environment of a low-turbulence flotation machine (impeller speed ≤200 rpm), and the reduction in turbulence intensity prevents mechanical damage to the agglomerates.

[0034] Ultimately, the hydrophobic agglomerates formed, due to their increased size and mass, have a significantly higher probability of adhesion during bubble collisions, enabling efficient recovery of fine molybdenum particles. This mechanism completely solves the core problem of low flotation efficiency for fine particles, avoids metal loss, and ensures overall optimization of flotation efficiency through the continuity and selectivity of the entire process.

[0035] In some embodiments, step S2 specifically includes: adding 0.1-0.3 kg / t of polyisobutylene succinimide to the dissociated slurry and stirring for 5-8 minutes; continuing to add 0.05 kg / t of sodium dimethyl dithiocarbamate to the slurry and stirring for 3-5 minutes to form an agglomerated slurry; and feeding the agglomerated slurry into a low-turbulence flotation machine for flotation.

[0036] In implementing this method, polyisobutylene succinimide is first added to the dissociated slurry at a dosage of 0.1 to 0.3 kg per ton of raw ore, and stirred for 5 to 8 minutes. During this stage, the molecular structure of polyisobutylene succinimide selectively adsorbs onto the surface of fine molybdenum minerals (-20 μm) through hydrophobic groups, forming a stable hydrophobic film layer, reducing the surface energy of the minerals. At the same time, its bridging effect promotes adjacent fine particles to approach and aggregate through van der Waals forces and hydrophobic attraction, forming larger agglomerates with a size of 50-100 micrometers. This significantly increases the effective diameter and mass of the particles, solving the problem that fine molybdenum particles are difficult to adhere to air bubbles due to their small size and light weight, thus improving flotation efficiency.

[0037] Next, sodium dimethyl dithiocarbamate is added to the slurry at a rate of 0.05 kg per ton of raw ore, and stirred for 3 to 5 minutes to form an agglomerated slurry. The thiocarbamate groups of sodium dimethyl dithiocarbamate synergistically enhance the hydrophobicity of the mineral surface and reduce electrostatic repulsion between particles through charge regulation, ensuring that the agglomerates remain stable and not easily dispersed in the slurry environment. This mechanism consolidates the integrity of the agglomerates, prevents the redispersibility of fine particles, further optimizes the agglomeration effect, and creates favorable conditions for subsequent flotation.

[0038] Finally, the agglomerated slurry is fed into a low-turbulence flotation machine for flotation. The calm characteristics of the low-turbulence environment (impeller speed ≤200 rpm) avoid mechanical damage to the agglomerates, and the probability of adhesion of the formed hydrophobic agglomerates during bubble collision is greatly increased, so that fine molybdenum particles can be recovered efficiently, and the core bottleneck of low flotation efficiency is completely overcome.

[0039] In some embodiments, the thickness of the foam layer in the stepped foam groove in step S3 is controlled to be ≥15 cm.

[0040] When implementing this method, the foam layer thickness in the stepped foam tank in step S3 is controlled to be ≥15 cm. This parameter is achieved by adjusting the height of the tailings gate. The working principle is as follows: the increase in foam layer thickness significantly prolongs the residence time of molybdenum mineral particles carried by bubbles. Especially for coarse-grained (+100 mesh) molybdenum minerals, under the inclined structure (inclination angle 25°-30°) of the stepped foam tank, the thicker foam layer provides a more stable hydrodynamic environment, effectively buffering turbulent disturbances, thereby reducing the probability of coarse molybdenum particles falling off the bubble surface due to inertial impact or gravity. At the same time, a foam layer thickness of ≥15 cm ensures that the continuous flow and enrichment process of foam is smoother, allowing bubbles sufficient space for selective separation. Coarse molybdenum minerals can be gradually concentrated in the foam layer without being easily lost, thereby optimizing the adhesion stability between minerals and bubbles. The beneficial effects of this mechanism are: the loss rate of coarse molybdenum particles is greatly reduced, significantly improving the total molybdenum recovery rate and avoiding the problem of coarse particle loss caused by the excessively thin foam layer in the existing technology; the improved foam enrichment efficiency also synergistically enhances the grade and purity of the concentrate, because the stable foam layer reduces the mixing of impurity minerals, ultimately overcoming the bottleneck of coarse molybdenum recovery and realizing efficient and continuous concentrate production.

[0041] In some embodiments, the thickness of the foam layer in the stepped foam tank is controlled to be 18-25 cm by adjusting the height of the tailings gate.

[0042] In implementing this method, the thickness of the foam layer in the stepped foam tank is precisely controlled within the range of 18-25 cm by adjusting the height of the tailings gate. The working principle of this mechanism is as follows: by raising or lowering the tailings gate height, the discharge rate of the slurry can be adjusted in real time, thereby dynamically maintaining the foam layer thickness within the optimized range. When the gate height increases, the slurry outflow slows down, and the foam layer thickens to the upper limit of 25 cm; conversely, lowering the gate height accelerates slurry discharge, causing the foam layer to thin to the lower limit of 18 cm. This adjustment ensures that the foam layer thickness is always in the ideal state of 18-25 cm. The physical principle behind this is that this thickness range significantly extends the residence time of coarse-grained molybdenum minerals (+100 mesh) carried by the bubbles.

[0043] In some embodiments, a copper inhibitor is added in step S3. The copper inhibitor is composed of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, and the total dosage is 0.3-0.5 kg / t of raw ore.

[0044] In implementing this method, the copper inhibitor added in step S3 consists of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, with the total dosage controlled at 0.3-0.5 kg / t of raw ore. This combination specifically addresses the problem of selective inhibition of copper minerals. Specifically, mercaptoacetic acid, as a sulfur-containing organic compound, has thiol (-SH) groups that preferentially form stable chelate complexes with copper ions on the surface of copper minerals (such as chalcopyrite), thereby covering the surface of the copper minerals and reducing their hydrophobicity, preventing them from effectively adhering to air bubbles. Simultaneously, sodium humate, as a natural high-molecular-weight organic acid, adsorbs onto the surface of copper minerals through its carboxyl and phenolic hydroxyl functional groups, further altering the surface charge and enhancing hydrophilicity, synergistically strengthening the inhibition effect. This 1:2 mass ratio optimizes the intermolecular synergistic effect: sodium humate provides a wide range of adsorption sites to "anchor" copper minerals, while mercaptoacetic acid precisely targets copper ion sites, ensuring the selectivity of the inhibition process and avoiding interference with the floatability of molybdenum minerals (such as molybdenite).

[0045] In the foam enrichment environment of the stepped foam tank, the addition of copper inhibitor combined with the dynamic flow of the foam layer further enhances the inhibition efficiency. The foam layer thickness is maintained at ≥15 cm (e.g., adjusted to 18-25 cm via tailings gates), combined with an inclined structure at an angle of 25°-30°, creating a low-turbulence, highly stable fluid environment. After the copper inhibitor is uniformly dispersed in the foam layer, its molecules can fully contact and act on the copper mineral particles. Due to the slow flow of the foam and the continuous rise of the bubbles, the copper minerals, after being encapsulated by the inhibitor, gradually settle or are carried away by the water flow, while the molybdenum minerals continue to accumulate with the bubbles. This process benefits from the buffering effect of the foam layer, reducing turbulent disturbances, making the copper inhibition reaction more thorough, and significantly increasing the probability of selective inhibition of copper minerals.

[0046] Through the above mechanism, the copper inhibitor effectively reduces the contamination of copper minerals in the concentrate, solving the problem of high copper impurity content (e.g., exceeding 0.6%) in the background technology. The synergistic effect of mercaptoacetic acid and sodium humate not only blocks the flotation path of copper minerals but also optimizes the purity of the concentrate. This is because the stable foam environment ensures the continuity of the inhibition reaction, preventing the reactivation or escape of copper minerals. Thus, while improving the grade of molybdenum concentrate, it achieves efficient and selective inhibition of copper minerals.

[0047] In some embodiments, the copper inhibitor is added in two stages to the stepped foam tank, with 60% of the total mass added at the bottom of the foam layer and the remaining 40% added in the middle of the foam layer.

[0048] In implementing this method, the copper inhibitor was designed to be added in two stages: first, 60% of the total mass was added to the bottom of the foam layer in the stepped foam tank, and the remaining 40% was added to the middle of the foam layer. This staged addition strategy specifically optimizes the copper inhibition process because the bottom of the foam layer is the inlet area of ​​the coarsely selected foam, where the concentration of copper minerals is relatively high. The initial addition of most of the copper inhibitor allows it to immediately utilize the thiol groups of mercaptoacetic acid to preferentially form stable chelate complexes with copper ions. At the same time, sodium humate adsorbs onto the surface of copper minerals through its carboxyl and phenolic hydroxyl functional groups, changing the surface charge and enhancing hydrophilicity, thus quickly establishing the initial inhibition layer. The addition of the remaining portion in the middle ensures that the concentration of copper inhibitor is continuously replenished as the foam slowly rises to the overflow port, preventing the copper minerals from being reactivated or escaping due to turbulent disturbances during the dynamic flow of the foam. This addition method fully utilizes the low turbulence and high stability environment created by the inclination angle (25°-30°) and foam layer thickness (≥15 cm) of the stepped foam tank, making the copper inhibition reaction more uniform and thorough, thereby significantly improving the selective inhibition efficiency of copper minerals, effectively reducing the mixing of copper impurities in molybdenum concentrate, and improving the purity and overall quality of the concentrate.

[0049] In some embodiments, the impeller speed of the low-turbulence flotation machine in step S2 is ≤200 rpm.

[0050] In the selective hydrophobic agglomeration flotation step of this method, the impeller speed of the low-turbulence flotation machine is controlled at 200. At speeds below rpm, the turbulence intensity within the flotation cell is significantly reduced, thereby decreasing fluid shear forces and bubble disturbance. This low-turbulence environment first helps maintain the stability of fine-particle hydrophobic molybdenum agglomerates (approximately 50-100 μm in size) induced by polyisobutylene succinimide (PIBSI), preventing agglomerate disintegration under high shear. This effectively solves the problem of low flotation efficiency caused by the difficulty in adhering to bubbles due to the small mass and large specific surface area of ​​fine-particle molybdenum (-20 μm), thus improving the recovery rate of fine-particle molybdenum. Simultaneously, the lower impeller speed reduces bubble breakage and slurry turbulence, lowering the probability of coarse-particle molybdenum (+100 mesh) detaching from bubbles and avoiding the loss of coarse-particle molybdenum minerals during flotation. Finally, this speed control synergistically optimizes the entire hydrophobic agglomeration process, not only improving the overall recovery rate of molybdenum concentrate but also enhancing flotation selectivity by reducing turbulence interference. This provides a more stable roughing froth input for subsequent stepped froth enrichment steps, thereby indirectly improving the purity and quality of the final molybdenum concentrate.

[0051] In some embodiments, the grinding media in step S1 are zirconia ceramic balls.

[0052] In implementing this method for extracting molybdenum concentrate by flotation, zirconia ceramic balls are used as the grinding media in step S1. The working principle is that the zirconia ceramic balls, with their high hardness and wear resistance, generate strong directional shear forces at high linear velocities (15-20 m / s), directly acting on the finely vein-embedded molybdenum minerals (such as the MoS2 layered structure of molybdenite). Combined with the added sodium dodecyl sulfate additive, this weakens the interlayer forces of the minerals, thereby efficiently stripping the mineral layers and achieving selective liberation. This mechanism solves the problem of insufficient liberation of finely vein-embedded molybdenum, avoids the ineffective circulation of unliberated molybdenum-copper intergrowths in the system, and reduces the over-grinding loss of fine molybdenum particles. In terms of beneficial effects, this design significantly improves liberation efficiency and selectivity, ensuring a purer liberated slurry in subsequent hydrophobic agglomeration flotation steps, indirectly optimizing the overall molybdenum recovery rate and concentrate quality. Simultaneously, by reducing turbulence interference and mineral loss, it provides a fundamental support for the economic efficiency and stability of the entire process.

[0053] In some embodiments, the ore returned for reprocessing in step S4 accounts for 15-30 wt% of the total ore feed in step S1.

[0054] In implementing this method for extracting molybdenum concentrate from flotation, the ore from the flotation process in step S4 is returned to step S1 for reprocessing. The returned ore accounts for 15-30 wt% of the total feed to step S1. This proportion is optimized for overall process efficiency by precisely controlling the material circulation rate. The working principle is that the ore from the flotation process mainly contains insufficiently liberated molybdenum minerals (such as veinlet molybdenite) and molybdenum-copper intergrowths. These materials were not effectively recovered in the initial flotation and are returned to a high-shear stirred mill for further interlayer shear-enhanced liberation treatment, combined with the auxiliary effect of sodium dodecyl sulfate. This design can further strip away the layered structure of minerals and release the encapsulated molybdenum particles. A ratio of 15-30 wt% ensures sufficient return to recover valuable molybdenum minerals, while avoiding excessively high ratios that could lead to system overload, increased energy consumption, or decreased dissociation efficiency, thus effectively interrupting ineffective recycling chains. Beneficially, this design significantly reduces fine-particle molybdenum loss and the retention of intergrowths in the system, improving molybdenum metal recovery. Simultaneously, by maintaining material balance and reducing turbulence interference, it optimizes the stability of subsequent flotation steps, indirectly enhancing the purity of the final molybdenum concentrate and the overall economic sustainability of the process.

[0055] The method of the present invention will now be described in detail with reference to embodiments, comparative examples and experimental data.

[0056] Example 1 This embodiment provides a specific implementation method for extracting molybdenum concentrate from molybdenum concentrate by flotation.

[0057] S1. The molybdenum concentrate and the reprocessed flotation ore are mixed and fed into a high-shear stirred mill for interlayer shear-enhanced liberation treatment. The high-shear stirred mill uses zirconia ceramic grinding media with a diameter of 4 mm and a linear velocity of 18 m / s. Sodium dodecyl sulfonate of 0.35 kg / t of raw ore is added. After the treatment, a liberated slurry is obtained.

[0058] S2. Add water to the liberated slurry to adjust the concentration to 30 wt%, and then feed it into a low-turbulence flotation machine with the impeller speed set to 200 rpm. Add 0.2 kg / t of polyisobutylene succinimide to the slurry and stir for 7 minutes. Then add 0.05 kg / t of sodium dimethyl dithiocarbamate and stir for 4 minutes to form an agglomerated slurry. Then, perform selective hydrophobic agglomerated flotation on the agglomerated slurry to obtain roughing froth and flotation medium.

[0059] S3. The roughing foam is fed into a stepped foam tank with an inclination angle of 28° for foam enrichment and copper inhibition treatment. The thickness of the foam layer in the stepped foam tank is controlled to be 22 cm by adjusting the height of the tailings gate. A copper inhibitor is added to the foam tank. The copper inhibitor is composed of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, with a total dosage of 0.4 kg / t of raw ore. The addition is carried out in two stages: 60% of the total mass is added to the bottom of the foam layer, and the remaining 40% is added to the middle of the foam layer. After the treatment, molybdenum concentrate is obtained.

[0060] S4. The flotation ore is returned to step S1 and mixed with molybdenum concentrate for reprocessing, wherein the flotation ore returned for reprocessing accounts for 23 wt% of the total feed in step S1.

[0061] Example 2 This embodiment provides a specific implementation method for extracting molybdenum concentrate from molybdenum concentrate by flotation.

[0062] S1. The molybdenum concentrate and the reprocessed flotation ore are mixed and fed into a high-shear stirred mill for interlayer shear-enhanced liberation treatment. The high-shear stirred mill uses zirconia ceramic grinding media with a diameter of 3 mm and a linear velocity of 15 m / s. Sodium dodecyl sulfonate of 0.3 kg / t of raw ore is added. After the treatment, a liberated slurry is obtained.

[0063] S2. Add water to the liberated slurry to adjust the concentration to 25 wt%, and then feed it into a low-turbulence flotation machine with the impeller speed set to 180 rpm. Add 0.15 kg / t of polyisobutylene succinimide to the slurry and stir for 7 minutes. Then add 0.04 kg / t of sodium dimethyl dithiocarbamate and stir for 4 minutes to form an agglomerated slurry. Then, perform selective hydrophobic agglomerated flotation on the agglomerated slurry to obtain roughing froth and flotation medium.

[0064] S3. The roughing foam is fed into a stepped foam tank with an inclination angle of 25° for foam enrichment and copper inhibition treatment. The thickness of the foam layer in the stepped foam tank is controlled to 20 cm by adjusting the height of the tailings gate. A copper inhibitor is added to the foam tank. The copper inhibitor is composed of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, with a total dosage of 0.3 kg / t of raw ore. The addition is carried out in two stages: 60% of the total mass is added to the bottom of the foam layer, and the remaining 40% is added to the middle of the foam layer. After the treatment, molybdenum concentrate is obtained.

[0065] S4. The flotation ore is returned to step S1 and mixed with molybdenum concentrate for reprocessing, wherein the flotation ore returned for reprocessing accounts for 20 wt% of the total feed amount in step S1.

[0066] Example 3 This embodiment provides a specific implementation method for extracting molybdenum concentrate from molybdenum concentrate by flotation.

[0067] S1. The molybdenum concentrate and the reprocessed flotation ore are mixed and fed into a high-shear stirred mill for interlayer shear-enhanced liberation treatment. The high-shear stirred mill uses zirconia ceramic grinding media with a diameter of 6 mm and a linear velocity of 22 m / s. Sodium dodecyl sulfonate of 0.5 kg / t of raw ore is added. After the treatment, a liberated slurry is obtained.

[0068] S2. Add water to the liberated slurry to adjust the concentration to 30 wt%, and then send it to a low-turbulence flotation machine with the impeller speed set to 300 rpm. Add 0.3 kg / t of polyisobutylene succinimide to the slurry and stir for 7 minutes. Then add 0.1 kg / t of sodium dimethyl dithiocarbamate and stir for 4 minutes to form an agglomerated slurry. Then, perform selective hydrophobic agglomerated flotation on the agglomerated slurry to obtain roughing froth and flotation medium.

[0069] S3. The roughing foam is fed into a stepped foam tank with an inclination angle of 28° for foam enrichment and copper suppression treatment. The thickness of the foam layer in the stepped foam tank is controlled to be 30 cm by adjusting the height of the tailings gate. A copper inhibitor is added to the foam tank. The copper inhibitor is composed of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, with a total dosage of 0.6 kg / t of raw ore. The addition is carried out in two stages: 60% of the total mass is added to the bottom of the foam layer, and the remaining 40% is added to the middle of the foam layer. After the treatment, molybdenum concentrate is obtained.

[0070] S4. The flotation ore is returned to step S1 and mixed with molybdenum concentrate for reprocessing, wherein the flotation ore returned for reprocessing accounts for 30 wt% of the total feed amount in step S1.

[0071] Comparative Example 1 This comparative example provides a method for extracting molybdenum concentrate by flotation from molybdenum concentrate. The difference from Example 1 is that the diameter of the grinding media is Φ2 mm.

[0072] Comparative Example 2 This comparative example provides a method for extracting molybdenum concentrate by flotation from molybdenum concentrate. The difference from Example 1 is that the amount of polyisobutylene succinimide used is 0.05 kg / t of raw ore.

[0073] Comparative Example 3 This comparative example provides a method for extracting molybdenum concentrate by flotation of molybdenum concentrate. The difference from Example 1 is that the thickness of the foam layer in the stepped foam tank is controlled to be 10 cm.

[0074] Comparative Example 4 This comparative example provides a method for extracting molybdenum concentrate from molybdenum concentrate by flotation. The difference from Example 1 is that the ore returned for reprocessing in the flotation accounts for 40 wt% of the total feed amount in S1.

[0075] The products corresponding to the above embodiments and comparative examples were tested using the following methods: 1. Molybdenum recovery rate (%): First, take a sample of molybdenum concentrate raw material, and after acid hydrolysis (nitric acid: hydrochloric acid = 3:1), determine the mass of molybdenum in the molybdenum concentrate using a spectrometer. Then, determine the mass of molybdenum in the molybdenum powder using the same method. Finally, calculate the molybdenum recovery rate: Molybdenum recovery rate (%) = (mass of molybdenum in molybdenum powder / mass of molybdenum in molybdenum concentrate) × 100%.

[0076] 2. Copper impurity content (%): The copper content in the molybdenum concentrate sample was analyzed using inductively coupled plasma atomic emission spectrometry. After acid hydrolysis (nitric acid to hydrochloric acid volume ratio 3:1), the copper mass was determined and the content was calculated: Copper impurity content (%) = (copper mass / total sample mass) × 100%.

[0077] 3. Particle size screening pass rate (%): A standard sieve with a 200-mesh sieve (75 μm aperture) was used for vibration screening for 10 minutes at a fixed amplitude. The particles that passed through the sieve were collected, weighed using an electronic balance (accuracy 0.001 g), and the following calculation was made: Particle size screening pass rate (%) = (mass of passing particles / total sample mass) × 100%.

[0078] Table 1 Performance Test Results

[0079] Experimental Results Analysis In Example 1, the molybdenum recovery rate reached 98.5%, the copper impurity content was 0.12%, and the particle size distribution rate was 93.5%. This indicates that the method performs well in terms of efficient molybdenum metal recovery, impurity control, and fine particle recovery, achieving synergistic optimization of metal recovery rate and product purity.

[0080] In Example 2, the molybdenum recovery rate was 97.2%, the copper impurity content was 0.15%, and the particle size distribution was 89.2%. The performance was slightly lower than that of Example 1, but it still maintained a high recovery rate, indicating that the method can still achieve stable results under different parameters.

[0081] In Example 3, the molybdenum recovery rate reached 99.1%, the copper impurity content was 0.09%, and the particle size screening pass rate was 96.8%, reaching the highest level, highlighting the significant role of optimized parameters in efficient molybdenum metal recovery, deep copper suppression, and particle size improvement.

[0082] In Comparative Example 1, the molybdenum recovery rate was only 95.0%, the copper impurity content was 0.18%, and the particle size screening pass rate was 85.4%, which was poor overall. The metal loss increased, reflecting that the grinding media was too small (Φ2 ​​mm), resulting in insufficient dissociation and directly affecting the recovery efficiency.

[0083] In Comparative Example 2, the molybdenum recovery rate dropped significantly to 92.3%, the copper impurity content was 0.21%, and the particle size screening pass rate was 78.9%. Insufficient agglomerant dosage led to the failure of hydrophobic agglomeration, which was the main reason for the simultaneous deterioration of metal recovery rate and particle size index.

[0084] In Comparative Example 3, the molybdenum recovery rate was 94.8%, the copper impurity content was 0.28%, and the particle size screening pass rate was 83.6%. The foam layer was too thin (10 cm), which seriously weakened the copper suppression effect, resulting in increased impurity entrainment and indirectly dragging down the recovery rate.

[0085] In Comparative Example 4, the molybdenum recovery rate dropped to 89.6%, the copper impurity content was 0.31%, and the particle size screening pass rate was 72.3%, which was the worst performance. The excessively high proportion of middlings recycling (40wt%) caused impurity accumulation, resulting in a comprehensive deterioration of metal recovery rate, product purity, and particle size.

[0086] Overall, all embodiments achieved molybdenum recovery rates ≥97.2%, copper impurities ≤0.15%, and particle size pass rates ≥89.2%, significantly better than the comparative examples. This indicates that the method, through optimized grinding and dissociation, hydrophobic agglomeration, and foam copper suppression, maximizes molybdenum metal recovery while ensuring purity and particle size control. This contrasts with the performance degradation caused by the parameter settings in the comparative examples, verifying the overall superiority of the flotation extraction method.

[0087] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A method for extracting molybdenum concentrate powder by flotation of molybdenum concentrate, characterized in that, Includes the following steps: S1. The molybdenum concentrate and the reprocessed flotation ore are mixed and fed into a high-shear stirred mill for interlayer shear-enhanced liberation treatment to obtain a liberated slurry. The high-shear stirred mill uses grinding media made of zirconium oxide ceramic or Al2O3 material, with a grinding media diameter of Φ3-5 mm, a linear velocity of 15-20 m / s, and 0.2-0.5 kg / t of sodium dodecyl sulfonate is added. S2. After adding water to adjust the concentration of the liberated slurry to 25-35wt%, it is sent to a low-turbulence flotation machine for selective hydrophobic agglomeration flotation to obtain rougher froth and flotation medium ore. S3. The coarsely selected foam is fed into a stepped foam tank with an inclination angle of 25°-30° for foam enrichment and copper suppression treatment to obtain molybdenum concentrate. S4. Return the ore from the flotation process to step S1 and mix it with the molybdenum concentrate for further processing.

2. The method according to claim 1, characterized in that, In step S2, a composite agglomerating agent is added, which comprises 0.1-0.3 kg / t of polyisobutylene succinimide and 0.05 kg / t of sodium dimethyl dithiocarbamate.

3. The method according to claim 2, characterized in that, The S2 step specifically includes: S21. Add 0.1-0.3 kg / t of polyisobutylene succinimide to the dissociated slurry and stir for 5-8 minutes; S22. Continue to add 0.05 kg / t of sodium dimethyl dithiocarbamate to the raw ore and stir for 3-5 minutes to form an agglomerated slurry; S23. Feed the agglomerated slurry into a low-turbulence flotation machine for flotation.

4. The method according to claim 1, characterized in that, In step S3, the thickness of the foam layer in the stepped foam tank is controlled to be ≥15 cm.

5. The method according to claim 4, characterized in that, The thickness of the foam layer in the stepped foam tank is controlled to be 18-25 cm by adjusting the height of the tailings gate.

6. The method according to claim 1 or 4, characterized in that, In step S3, a copper inhibitor is added. The copper inhibitor is composed of mercaptoacetic acid and sodium humate in a mass ratio of 1:2, and the total dosage is 0.3-0.5 kg / t of raw ore.

7. The method according to claim 6, characterized in that, The copper inhibitor is added in two stages to the stepped foam tank. The first stage adds 60% of the total mass to the bottom of the foam layer, and the remaining 40% to the middle of the foam layer.

8. The method according to claim 1, characterized in that, In step S2, the impeller speed of the low-turbulence flotation machine is ≤200 rpm.

9. The method according to claim 1, characterized in that, In step S1, the grinding media is zirconia ceramic balls.

10. The method according to claim 1, characterized in that, In step S4, the ore returned for reprocessing in flotation accounts for 15-30 wt% of the total feed in step S1.

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