Beneficiation method for improving molybdenum index by using low-alkali flotation environment

Abstract

The present application relates to copper-molybdenum ore dressing technical field, specifically a kind of beneficiation method for recovering copper-molybdenum sulfide ore using low-alkali flotation environment.The method comprises the following steps, S1: after grinding copper-molybdenum sulfide ore, molybdenum reverse flotation is carried out, to obtain molybdenum rough concentrate and copper-sulfur mixed concentrate;S2: the molybdenum rough concentrate is subjected to molybdenum cleaning, to obtain molybdenum concentrate and gangue;S3: the copper-sulfur mixed concentrate is subjected to copper flotation, to obtain copper concentrate and final tailings.The present application carries out molybdenum reverse flotation in low-alkali environment, avoiding the strong inhibition of high-alkali environment on molybdenite.The present application does not add lime in the molybdenum reverse flotation stage, avoiding the introduction of a large amount of calcium ions from the source, which effectively prevents the formation of hydrophilic calcium molybdate film or calcium hydroxide, calcium carbonate and other precipitates on the surface of molybdenite, thereby maintaining the hydrophobicity and good floatability of the surface of molybdenite, and avoiding the problem of molybdenum recovery rate reduction caused by calcium ion pollution in traditional high-alkali process.

Description

Technical Field

[0001] This invention relates to the field of copper-molybdenum ore beneficiation technology, specifically a beneficiation method for recovering copper-molybdenum sulfide ore using a low-alkali flotation environment. Background Technology

[0002] Copper-molybdenum deposits refer to porphyry-type metallic deposits where copper and molybdenum are coexisting minerals. They mainly exist in the form of sulfide minerals, and are therefore also known in a narrow sense as copper-molybdenum sulfide deposits. Copper minerals mainly exist in the form of chalcopyrite, bornite, and chalcocite, while molybdenum minerals mainly exist in the form of molybdenite. Other minerals include sulfide gangue minerals such as pyrite, as well as other gangue minerals such as quartz and feldspar.

[0003] Separating copper-molybdenum ores requires overcoming several challenges. First, molybdenite and chalcopyrite are closely associated and have similar floatability, making separation by liberation and flotation difficult. Second, copper-sulfur coexistence is common, making the separation of chalcopyrite and pyrite more challenging.

[0004] The current traditional method for recovering copper-molybdenum ore is to first suppress sulfur to float copper and molybdenum, and then suppress copper to float molybdenum. Specifically, a large amount of lime is added to the slurry as a pyrite inhibitor to create a highly alkaline environment (pH > 10.5), enabling the mixed flotation of copper-molybdenum minerals with sulfur minerals to obtain a mixed copper-molybdenum concentrate. However, this method has significant drawbacks. First, the highly alkaline environment partially inhibits the flotation of molybdenite, resulting in a low molybdenum recovery rate in the mixed concentrate. Second, the large amount of lime and calcium ions remaining in the mixed concentrate severely interferes with subsequent copper-molybdenum separation, leading to difficulties in separation, high reagent consumption, and unsatisfactory molybdenum concentrate grade and recovery rate.

[0005] To overcome the above problems, there is an urgent need for a method different from traditional methods to recover copper and molybdenum from copper-molybdenum sulfide ores in a low-alkali flotation environment. Summary of the Invention

[0006] The purpose of this invention is to provide a mineral processing method for recovering copper-molybdenum sulfide ores using a low-alkali flotation environment, so as to achieve at least the effect of efficiently recovering high-grade molybdenum concentrate and copper concentrate and improving the molybdenum recovery rate.

[0007] The objective of this invention is achieved through the following technical solution: A mineral processing method for improving molybdenum content using a low-alkali flotation environment includes the following steps: S1: After grinding the copper-molybdenum sulfide ore, molybdenum reverse flotation is performed to obtain molybdenum rough concentrate and copper-sulfur mixed concentrate; S2: The molybdenum rough concentrate is subjected to molybdenum beneficiation to obtain molybdenum concentrate and gangue; S3: The copper-sulfur mixed concentrate is subjected to copper flotation to obtain copper concentrate and final tailings.

[0008] In some embodiments, the flotation reagents used in the molybdenum reverse flotation include a pH adjuster, a molybdenum inhibitor, a copper-sulfur collector, and a frother, adjusting the pulp pH to 7-9.

[0009] In some examples, the pH adjuster includes at least one of sodium carbonate or sodium bicarbonate; the molybdenum inhibitor includes at least one of dextrin and gum arabic; the copper-sulfur collector includes butyl xanthate; and the foaming agent includes at least one of MIBC and HCCL.

[0010] In some examples, step S1, the molybdenum reverse flotation, includes a coarse flotation, a fine flotation, and a scavenging process.

[0011] For example, the roughing flotation process involves adjusting the pH of the pulp to 7-9 using a pH adjuster, followed by adding the molybdenum inhibitor, copper-sulfur collector, and frother for flotation, resulting in roughing concentrate a and roughing tailings a. The flotation process of the first concentrate is to add the frother and molybdenum inhibitor to the slurry of the rough concentrate a and carry out flotation to obtain middlings a and the copper-sulfur mixed concentrate. Middlings a is then returned. The flotation process of the first scavenger is to add the frother and copper-sulfur collector to the slurry of the roughing tailings a and then float it to obtain middlings b and the molybdenum rough concentrate. Middlings b is then returned.

[0012] In some embodiments, the flotation reagents used in the copper flotation include copper collectors, carbon inhibitors, and quicklime, and the pulp pH is adjusted to 11-12.

[0013] In some examples, the copper collector includes at least one of isobutyl xanthate and allyl isothiourea; the carbon inhibitor includes at least one of ferric chloride, sodium hexametaphosphate, and water glass.

[0014] In some examples, the copper flotation process includes a coarse flotation, a fine flotation, and a scavenging process.

[0015] For example, the roughing flotation process involves adjusting the pH of the pulp to 11-12 using quicklime, then adding the copper collector and carbon inhibitor for flotation, resulting in roughing concentrate A and roughing tailings A.

[0016] The flotation process of the first concentrate involves adding the carbon inhibitor to the rougher concentrate A for flotation to obtain middlings A and the copper concentrate, with middlings A being returned.

[0017] The flotation process of the first scavenging step involves adding the copper collector to the roughing tailings A for flotation to obtain middlings B and the final tailings, with middlings B being returned.

[0018] It is worth noting that while highly alkaline environments can suppress pyrite, they also suppress molybdenite. Furthermore, the large introduction of calcium ions can form a hydrophilic film or precipitate on the surface of molybdenite, significantly reducing the floatability of both pyrite and molybdenite, thus lowering the molybdenum recovery rate in the copper-molybdenum mixed concentrate. Conversely, in low-alkaline environments, the suppression of molybdenite weakens, but the suppression of pyrite also weakens, allowing some pyrite to enter the copper-molybdenum mixed concentrate, leading to a lower concentrate grade.

[0019] Based on this, the present invention provides a method for reverse flotation of molybdenum concentrate in a low-alkali environment. First, molybdenum reverse flotation is performed under low-alkali conditions, using a molybdenum depressant to selectively inhibit molybdenite, while butyl xanthate is used as a collector to float chalcopyrite and pyrite, thus achieving preliminary separation of molybdenite from copper-sulfur minerals under low-alkali conditions. Subsequently, the rough molybdenum concentrate is further refined to separate gangue, obtaining a high-grade molybdenum concentrate. Finally, copper flotation is performed on the mixed minerals of chalcopyrite and pyrite to separate copper concentrate and final tailings. This method achieves efficient molybdenum recovery under low-alkali conditions, avoiding many drawbacks of high-alkali processes and preventing the introduction of calcium ions from affecting the recovery rate of molybdenum concentrate.

[0020] The beneficial effects of this invention are: 1. This invention performs molybdenum reverse flotation in a low-alkali environment, avoiding the strong inhibition of molybdenite by a high-alkali environment. The low-alkali flotation process can significantly improve the molybdenum recovery rate, better maintain the natural floatability of molybdenite, and achieve efficient separation of molybdenite from copper-sulfur minerals.

[0021] 2. This invention does not add lime in the molybdenum reverse flotation stage, thus avoiding the introduction of a large amount of calcium ions from the source. This effectively prevents calcium ions from forming a hydrophilic calcium molybdate film or calcium hydroxide, calcium carbonate and other precipitates on the surface of molybdenite, thereby maintaining the hydrophobicity and good floatability of the molybdenite surface and avoiding the problem of decreased molybdenum recovery rate caused by calcium ion contamination in traditional high-alkali processes. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the mineral processing flow in Embodiment 1 of the present invention. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0024] Example 1 This embodiment provides a mineral processing method for improving molybdenum content using a low-alkali flotation environment. The specific method is as follows: 1) Grinding: Take 1 t of copper-molybdenum sulfide ore A (containing 0.70% copper, 0.012% molybdenum, and 3.25% sulfur) for grinding. The grinding fineness is -0.074 mm, accounting for 65%.

[0025] 2) Molybdenum reverse flotation: The ground slurry is fed into the flotation cell, sodium carbonate is added to adjust the pH of the slurry to 8±0.5, and then molybdenum reverse flotation is carried out. The flotation regime is as follows:

[0026] Reverse flotation employs a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: Dextrin, butyl xanthate and MIBC are added to the milled slurry for roughing to obtain roughing concentrate and roughing tailings; First-stage refining: MIBC and dextrin are added to the roughing concentrate for refining to obtain middlings (returned to roughing) and copper-sulfur mixed concentrate; First scavenging: MIBC and butyl xanthate are added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and molybdenum concentrate.

[0027] 3) Molybdenum Concentration: The rough molybdenum concentrate is regrinded to a fineness of -0.043 mm or higher (over 90%). 1000 g / t of water glass and 150 g / t of kerosene are added to the slurry as a gangue dispersant, and flotation is performed to obtain molybdenum concentrate and gangue slag.

[0028] 4) Copper flotation: The pH of the copper-sulfur mixed concentrate pulp was adjusted to 11.5±0.5 using quicklime, followed by copper flotation. The flotation regime is as follows:

[0029] Copper flotation employs a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: Isobutyl xanthate and sodium hexametaphosphate are added to the copper-sulfur mixed concentrate for roughing to obtain rough concentrate and rough tailings; First refining: Sodium hexametaphosphate is added to the rough concentrate for refining to obtain middlings (returned to rough concentrate) and copper concentrate; First scavenging: Isobutyl xanthate is added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and final tailings.

[0030] 5) The closed-circuit test yielded the following results: molybdenum concentrate grade 35.86%, molybdenum recovery rate 74.57%; copper concentrate grade 23.81%, copper recovery rate 94.72%.

[0031] Example 2 This embodiment provides a mineral processing method for improving molybdenum index using a low-alkali flotation environment. The method is the same as in Embodiment 1, except for the reagent formulation, as detailed below: This embodiment provides a mineral processing method for improving molybdenum content using a low-alkali flotation environment. The specific method is as follows: 1) Grinding: Take 1 t of copper-molybdenum sulfide ore A (containing 0.70% copper, 0.012% molybdenum, and 3.25% sulfur) for grinding. The grinding fineness is -0.074 mm, accounting for 65%.

[0032] 2) Molybdenum reverse flotation: The ground slurry is fed into the flotation cell, sodium carbonate is added to adjust the pH of the slurry to 8±0.5, and then molybdenum reverse flotation is carried out. The flotation regime is as follows:

[0033] Reverse flotation employs a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: Dextrin, butyl xanthate and MIBC are added to the milled slurry for roughing to obtain roughing concentrate and roughing tailings; First-stage refining: HCl and dextrin are added to the roughing concentrate for refining to obtain middlings (returned to roughing) and copper-sulfur mixed concentrate; First scavenging: HCCL and butyl xanthate are added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and molybdenum concentrate.

[0034] 3) Molybdenum Concentration: The rough molybdenum concentrate is regrinded to a fineness of -0.043 mm or higher (over 90%). 1000 g / t of water glass and 150 g / t of kerosene are added to the slurry as a gangue dispersant, and flotation is performed to obtain molybdenum concentrate and gangue slag.

[0035] 4) Copper flotation: The pH of the copper-sulfur mixed concentrate pulp was adjusted to 11.5±0.5 using quicklime, followed by copper flotation. The flotation regime is as follows:

[0036] Copper flotation employs a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: Propylene isothiourea and water glass are added to the copper-sulfur mixed concentrate for roughing to obtain rough concentrate and rough tailings; First refinement: Water glass is added to the rough concentrate for further refinement, resulting in middlings (returned to rough concentrate) and copper concentrate; First scavenging: Propylene isothiourea is added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and final tailings.

[0037] 5) The closed-circuit test yielded the following results: molybdenum concentrate grade 38.26%, molybdenum recovery rate 71.69%; copper concentrate grade 23.59%, copper recovery rate 95.04%.

[0038] Example 3 This embodiment provides a mineral processing method for improving molybdenum content using a low-alkali flotation environment. The method is the same as in Embodiment 1, except that the source of the raw ore used is different, as detailed below: 1) Grinding: Take 1 t of copper-molybdenum sulfide ore B (containing 0.65% copper, 0.021% molybdenum, and 1.58% carbon) and grind it to a fineness of -0.074 mm, accounting for 65%.

[0039] 2) Molybdenum reverse flotation: The ground slurry is fed into the flotation cell, sodium carbonate is added to adjust the pH of the slurry to 8±0.5, and then molybdenum reverse flotation is carried out. The flotation regime is as follows:

[0040] Reverse flotation employs a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: Dextrin, butyl xanthate and MIBC are added to the milled slurry for roughing to obtain roughing concentrate and roughing tailings; First-stage refining: MIBC and dextrin are added to the roughing concentrate for refining to obtain middlings (returned to roughing) and copper-sulfur mixed concentrate; First scavenging: MIBC and butyl xanthate are added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and molybdenum concentrate.

[0041] 3) Molybdenum Concentration: The rough molybdenum concentrate is regrinded to a fineness of -0.043 mm or higher (over 90%). 1000 g / t of water glass and 150 g / t of kerosene are added to the slurry as a gangue dispersant, and flotation is performed to obtain molybdenum concentrate and gangue slag.

[0042] 4) Copper flotation: The pH of the copper-sulfur mixed concentrate pulp was adjusted to 11.5±0.5 using quicklime, followed by copper flotation. The flotation regime is as follows:

[0043] Copper flotation employs a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: Isobutyl xanthate and sodium hexametaphosphate are added to the copper-sulfur mixed concentrate for roughing to obtain rough concentrate and rough tailings; First refining: Sodium hexametaphosphate is added to the rough concentrate for refining to obtain middlings (returned to rough concentrate) and copper concentrate; First scavenging: Isobutyl xanthate is added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and final tailings.

[0044] 5) The closed-circuit test yielded the following results: molybdenum concentrate grade 42.75%, molybdenum recovery rate 80.26%; copper concentrate grade 24.71%, copper recovery rate 94.86%.

[0045] Comparative Example 1 This comparative example provides a conventional method for beneficiating copper-molybdenum sulfide ores, as follows: 1) Grinding: Take copper-molybdenum sulfide ore A1t and grind it to a fineness of -0.074mm, accounting for 65%.

[0046] 2) Copper-molybdenum-sulfur mixed flotation: The ground ore pulp is fed into the flotation cell, using a traditional high-alkali lime process. A large amount of quicklime is added to adjust the pulp pH to 11-12 for copper-molybdenum-sulfur mixed flotation. The flotation regime is as follows:

[0047] The copper-molybdenum-sulfur mixed flotation adopts a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: BK345, BK404C and MIBC are added to the post-grind slurry for roughing to obtain roughing concentrate and roughing tailings; First-stage refining: BK345, BK404C and MIBC are added to the roughing concentrate for refining to obtain middlings (returned to roughing) and copper-molybdenum mixed concentrate; First scavenging: BK345, BK404C and MIBC are added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and tailings (mainly containing pyrite).

[0048] 3) Copper-molybdenum separation: The copper-molybdenum mixed concentrate is regrinded to a fineness of -0.043 mm or higher (over 90%). Copper inhibitor (KMD135, Na2S:NaHS=3:7), carbon inhibitor, and molybdenum collector are added to the pulp for copper-molybdenum separation flotation. The flotation regime is as follows:

[0049] The copper-molybdenum separation flotation adopts a flotation process consisting of one roughing, one cleaning, and one scavenging step: First roughing: KMD135, sodium hexametaphosphate and BK404C are added to the slurry after grinding for roughing to obtain roughing concentrate and roughing tailings; First stage: Carbonaceous inhibitor and KMD135 are added to the roughing concentrate for further cleaning to obtain middlings (returned to roughing) and molybdenum concentrate; First scavenging: Carbonaceous depressant and BK404C are added to the roughing tailings for scavenging to obtain middlings (returned to roughing) and copper concentrate.

[0050] 4) The closed-circuit test yielded the following results: molybdenum concentrate grade 35.91%, molybdenum recovery rate 65.72%; copper concentrate grade 23.64%, copper recovery rate 94.53%.

[0051] As can be seen, pyrite is strongly inhibited by lime under high-alkali conditions, but molybdenite is also strongly inhibited, resulting in a molybdenum recovery rate of only 65.72%, significantly lower than in the embodiments of this invention. This indicates that the high-alkali lime process significantly inhibits molybdenite. Simultaneously, a large number of calcium ions form a hydrophilic calcium molybdate film or calcium hydroxide / calcium carbonate precipitate on the surface of molybdenite, further deteriorating its floatability and leading to molybdenum loss. In contrast, this invention achieves preliminary and efficient separation of molybdenite and copper-sulfur minerals by first performing molybdenum reverse flotation under low-alkali conditions, selectively inhibiting molybdenite using dextrin and other inhibitors, and capturing copper-sulfur minerals with butyl xanthate. Furthermore, no lime is added throughout the process, preventing the introduction of calcium ions at the source and protecting the natural hydrophobic surface of molybdenite. Subsequently, the molybdenum concentrate is regrinded and refined to obtain a high-grade molybdenum concentrate. Finally, the copper-sulfur mixed concentrate is subjected to high-alkali copper flotation to ensure copper recovery. This process not only increases the molybdenum recovery rate by up to 15 percentage points compared to traditional high-alkali processes but also maintains a copper recovery rate of over 94%, demonstrating excellent performance.

[0052] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A mineral processing method for improving molybdenum index using a low-alkali flotation environment, characterized in that, Includes the following steps: S1: After grinding the copper-molybdenum sulfide ore, molybdenum reverse flotation is performed to obtain molybdenum rough concentrate and copper-sulfur mixed concentrate; S2: The molybdenum rough concentrate is subjected to molybdenum beneficiation to obtain molybdenum concentrate and gangue; S3: The copper-sulfur mixed concentrate is subjected to copper flotation to obtain copper concentrate and final tailings.

2. The mineral processing method according to claim 1, characterized in that: The flotation reagents used in the molybdenum reverse flotation include pH adjuster, molybdenum inhibitor, copper-sulfur collector and frother, and the pulp pH is adjusted to 7-9.

3. The mineral processing method according to claim 2, characterized in that: The pH adjuster includes at least one of sodium carbonate or sodium bicarbonate; the molybdenum inhibitor includes at least one of dextrin and gum arabic; the copper-sulfur collector includes butyl xanthate; and the foaming agent includes at least one of MIBC and HCCL.

4. The mineral processing method according to claim 2, characterized in that: In step S1, the molybdenum reverse flotation includes a roughing, a finishing, and a scavenging process.

5. The mineral processing method according to claim 4, characterized in that: The roughing flotation process involves adjusting the pH of the pulp to 7-9 using a pH adjuster, followed by adding the molybdenum inhibitor, copper-sulfur collector, and frother for flotation, resulting in roughing concentrate a and roughing tailings a. The flotation process of the first concentrate is to add the frother and molybdenum inhibitor to the slurry of the rough concentrate a and carry out flotation to obtain middlings a and the copper-sulfur mixed concentrate. Middlings a is then returned. The flotation process of the first scavenger is to add the frother and copper-sulfur collector to the slurry of the roughing tailings a and then float it to obtain middlings b and the molybdenum rough concentrate. Middlings b is then returned.

6. The mineral processing method according to claim 1, characterized in that: The flotation reagents used in the copper flotation include copper collectors, carbon inhibitors, and quicklime, and the pulp pH is adjusted to 11-12.

7. The mineral processing method according to claim 6, characterized in that: The copper collector includes at least one of isobutyl xanthate and allyl isothiourea; the carbon inhibitor includes at least one of ferric chloride, sodium hexametaphosphate and water glass.

8. The mineral processing method according to claim 6, characterized in that: The copper flotation process includes a roughing, a finishing, and a scavenging step.

9. The mineral processing method according to claim 8, characterized in that: The roughing flotation process involves adjusting the pH of the pulp to 11-12 using quicklime, then adding the copper collector and carbon inhibitor for flotation, resulting in roughing concentrate A and roughing tailings A. The flotation process of the first concentrate is to add the carbon inhibitor to the rough concentrate A and perform flotation to obtain middlings A and the copper concentrate, and middlings A is returned. The flotation process of the first scavenging step involves adding the copper collector to the roughing tailings A for flotation to obtain middlings B and the final tailings, with middlings B being returned.

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