Pre-oxidation-magnetic-flotation combined beneficiation process for strengthening separation of copper-molybdenum bulk concentrate

Abstract

The invention discloses a pre-oxidation-magnetic-flotation combined beneficiation process for strengthening separation of copper-molybdenum bulk concentrate. The method comprises the following steps: (1) carrying out pre-oxidation treatment on copper-molybdenum bulk concentrate; the method comprises the following steps: stirring and mixing an oxidant solution with a certain concentration with minerals, filtering after reaction, and washing the surface with deionized water to obtain initial raw ores; (2) the initial raw ore is subjected to pulp mixing to form ore pulp, the ore pulp is added into a high-gradient magnetic separator for magnetic separation, magnetic products and non-magnetic products are obtained through two times of strong magnetic separation under a certain magnetic field intensity, and the magnetic products are copper concentrates; and (3) the magnetic separation middlings and the non-magnetic products are combined to be subjected to flotation, one-time roughing, three-time concentration and three-time scavenging are adopted in the flotation process, an inhibitor, a collecting agent and a foaming agent are sequentially added, air inflation is started for flotation separation after uniform stirring, and flotation concentrates are molybdenum concentrates. The invention has the characteristics of lower energy consumption, lower production cost and better sorting effect.

Description

Technical Field

[0001] The present invention relates to the technical field of efficient copper-molybdenum separation, and in particular to a pre-oxidation-magnetic-flotation combined beneficiation process for enhancing the separation of copper-molybdenum mixed concentrates. Background Art

[0002] Copper and molybdenum are important nonferrous metal resources. Copper-molybdenum ores are mainly found in the form of porphyry-type copper-molybdenum deposits and skarn-type copper-molybdenum deposits. Their copper sulfides (mainly chalcopyrite) are usually closely associated with molybdenite. Chalcopyrite and molybdenite have similar floatability and small difference in surface wettability, making separation difficult. At present, the use of sodium thioglycolate as a copper mineral inhibitor alone can no longer meet the needs of difficult-to-separate copper and molybdenum separation, as poor, fine, and mixed refractory molybdenum ores have many types of copper sulfide minerals and are closely associated with molybdenite. The specific magnetic susceptibility of chalcopyrite is 0.840×10 -6 m 3 / kg, it is a weakly magnetic mineral, and the specific magnetic susceptibility of molybdenite is -0.001×10 -6 m 3 / kg, there is a magnetic difference between the two, so theoretically the two can be separated by high gradient strong magnetic separation.

[0003] But in general, the difference in magnetic properties between chalcopyrite and molybdenite is small, resulting in serious intermixing of copper and molybdenum minerals in the magnetic separation products and poor separation effect. Pre-oxidation technology can change the difference in surface components between the two, thereby affecting their floatability and making a difference in the magnetic flotation effect. By stirring the oxidant solution with the copper-molybdenum mixed concentrate, an oxidation reaction occurs on the mineral surface to generate corresponding oxidation products. Chalcopyrite is easily oxidized due to its surface properties, generating soluble copper salts, which changes its surface floatability. Molybdenite is not easily oxidized due to its stable surface properties. Therefore, pre-oxidation not only enhances the surface magnetism of chalcopyrite, but also plays a role in de-doping the copper-molybdenum mixed concentrate, changes the surface hydrophilicity and hydrophobicity of its products, and enhances the flotation separation effect.

[0004] Existing copper-molybdenum separation technology involves grinding the copper-molybdenum mixed ore in a ball mill, followed by roughing, followed by secondary regrinding. After three rounds of concentrating and scavenging, molybdenum concentrate is obtained. This technology suffers from excessive reagent consumption, resulting in waste. Furthermore, the secondary regrinding requires significant energy consumption, and flotation columns can easily cause coarse separation, reducing molybdenum recovery and resulting in molybdenum losses.

[0005] Publication number CN118950268A discloses a method for separating and removing drugs from copper and molybdenum. The method involves removing drugs from a copper-molybdenum mixed concentrate slurry to obtain a copper-molybdenum separated slurry. Inorganic inhibitors, small-molecule organic inhibitors, and large-molecule organic inhibitors are added to the copper-molybdenum separated slurry, followed by a collector for roughing to obtain a rougher concentrate and rougher tailings. The rougher concentrate is then subjected to beneficiation to obtain a molybdenum concentrate, and the rougher tailings are subjected to scavenging to obtain a copper concentrate. However, the method involves a wide variety of reagents and consumes excessive amounts, which is not conducive to efficient utilization of minerals.

[0006] Publication number CN114471935A discloses a method for separating copper-molybdenum mixed concentrates by magnetic levitation. However, due to the small magnetic difference between copper and molybdenum, strong magnetic separation can partially separate copper and molybdenum, but a lot of copper ore still remains in the tailings, making efficient separation impossible. In addition, the molybdenum grade contained in the magnetic product during the magnetic separation process is high, and the molybdenum loss rate is high, which is not conducive to the comprehensive recovery of molybdenum.

[0007] At present, no effective processing technology for raw ore has been found. Summary of the Invention

[0008] In order to overcome the above technical problems, the purpose of the present invention is to provide a pre-oxidation-magnetic-flotation combined mineral processing process for enhancing the separation of copper-molybdenum mixed concentrates, which has the characteristics of low energy consumption, low production cost and good sorting effect.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A pre-oxidation-magnetic-flotation combined beneficiation process for enhancing the separation of copper-molybdenum mixed concentrates comprises the following steps:

[0011] Step (1): pre-oxidizing the copper-molybdenum mixed concentrate; stirring and mixing a certain concentration of oxidant solution with the mineral, filtering after the reaction is completed, and then washing the surface with deionized water to obtain the initial raw ore;

[0012] Step (2): After the initial raw ore is slurried to form a slurry, it is added to a high gradient magnetic separator for magnetic separation. Under a certain magnetic field strength, two strong magnetic separations are performed to obtain a magnetic product, a non-magnetic product and a magnetically separated ore. The magnetic product is a copper concentrate.

[0013] Step (3): Combine the magnetically separated ore and non-magnetic products into flotation. The flotation process adopts one roughing process + three cleaning processes + three scavenging processes. Inhibitors, collectors and frothers are added in the roughing process and the scavenging process respectively. Only inhibitors are added to the cleaning process. After stirring evenly, aeration is started for flotation separation. The flotation concentrate is molybdenum concentrate.

[0014] As a preferred solution, in step (1), in order to better oxidize the copper-molybdenum mineral, 0.3 mol / L hydrogen peroxide solution and copper-molybdenum mixed concentrate are selected in a mass ratio of 2:1 to 1.5:1 and fused and stirred, and the oxidation time is selected to be 15-20 min.

[0015] As a preferred solution, in step (2), during the primary magnetic separation process, the pulp concentration is adjusted to 20% to 30%, the water flow rate is 2 L / min to 1.5 L / min, the magnetic induction intensity is 1.7 to 1.5 T, and the pulsation frequency is 100 to 120 r / min.

[0016] As a preferred solution, in step (2), during the secondary magnetic separation process, the pulp concentration is adjusted to 20% to 30%, the water flow rate is 2L / min to 1.5L / min, the magnetic induction intensity is 1.6 to 1.4T, and the pulsation frequency is 100 to 120r / min.

[0017] As a preferred solution, in step (2), the secondary magnetic separation effectively improves the copper grade in the magnetic concentrate, reduces the copper content in the non-magnetic product, and reduces the amount of flotation depressant used.

[0018] As a preferred solution, in the step (3), the inhibitor in the roughing and scavenging processes is sodium thioglycolate, sodium sulfide, and sodium hydrosulfide in a mass ratio of (1:5 to 1:10) or sodium thioglycolate is used alone; the amount of sodium thioglycolate used in the roughing of the combined inhibitor is 80 to 200 g / t; the amount of sodium thioglycolate used in the scavenging of the combined inhibitor is 30 to 100 g / t, which can effectively inhibit the flotation of chalcopyrite and enhance the copper-molybdenum separation efficiency.

[0019] As a preferred solution, in the step (3), the collector used in the roughing and scavenging is one of kerosene and diesel or they are used in combination according to a mass ratio of (1:1 to 1:2), and the amount of kerosene in the combined collector is 100 to 300 g / t, so as to achieve effective capture of molybdenum.

[0020] As a preferred solution, in step (3), the foaming agent in the roughing process is at least one of terpineol, methyl isobutyl carbinol, and diethyl phthalate, and the amount of the foaming agent added is 50 to 100 g / t.

[0021] As a preferred solution, in the step (3), the inhibitor in the beneficiation process is sodium thioglycolate, sodium sulfide, and sodium hydrosulfide in a mass ratio of (1:5 to 1:10) or sodium thioglycolate is used alone; the amount of crude sodium thioglycolate in the combined inhibitor is 50 to 100 g / t;

[0022] As a preferred solution, in step (3), the roughing flotation time is 8 to 11 minutes, and the cleaning and scavenging time is 5 to 8 minutes.

[0023] The copper-molybdenum mixed concentrate has a particle size of -200 mesh, with a proportion greater than 70%, a molybdenum grade of 6%-9%, and a copper grade ratio greater than 0.3%.

[0024] (1) The present invention provides a separation method and separation process with strong adaptability, high separation efficiency and separation depth, based on the characteristics of copper and molybdenum minerals. High-quality molybdenum concentrate is obtained through a combined process of ore pre-oxidation-magnetic separation-flotation. Pre-oxidation increases the magnetic difference between the two, and the two strong magnetic separations can effectively enrich copper. Flotation promotes the improvement of molybdenum quality and the reduction of impurities, thereby increasing the molybdenum grade in the molybdenum concentrate and reducing the impurity copper content.

[0025] (2) The pre-oxidation process of the present invention fully utilizes the properties of the reagents, and a strong oxidant (hydrogen peroxide, ozone, hypochlorous acid, etc.) is selected to oxidize the copper. This increases the surface magnetic difference, so that the subsequent magnetic separation process can better achieve copper enrichment. At the same time, the properties of molybdenum do not change much, thereby reducing its loss in magnetic separation. The flotation process of the non-magnetic product further improves the grade and recovery rate of molybdenum.

[0026] (3) The present invention is aimed at separating copper-molybdenum mixed concentrates by two strong magnetic separations, and the flotation is a roughing separation followed by three fine separations and three scavenging separations. After two magnetic separations, the Cu grade in the magnetic product obtained is significantly improved, indicating that Cu is largely enriched in the magnetic product. The Mo grade in the non-magnetic product also increases accordingly, indicating that magnetic separation can effectively separate copper and molybdenum. After the non-magnetic product and the magnetically separated ore are combined and flotation is performed, the molybdenum concentrate obtained has Cu < 0.1%, Mo > 45%, and a Mo loss rate of no more than 5%. The separation effect is obvious, the production energy consumption is low, and the amount of reagents used is greatly reduced.

[0027] The method for preparing molybdenum concentrate by separating copper and molybdenum of the present invention has simple steps, strong operability and strong adaptability to raw materials; the obtained molybdenum concentrate can meet the original requirements of major molybdenum companies for producing molybdenum concentrate powder, and solves the current problems of poor copper-molybdenum separation effect, high production energy consumption and poor indicators. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the present invention.

[0029] Figure 2 Schematic diagram of the magnetic changes of chalcopyrite and molybdenite after pre-oxidation. DETAILED DESCRIPTION

[0030] The present invention will be described in further detail below with reference to the accompanying drawings.

[0031] Example 1

[0032] The molybdenum content of a copper-molybdenum mixed coarse concentrate is 6.97%, the copper content is 0.42%, and the other gangue minerals are mainly quartz (41%) and mica (20%). The -200 mesh size accounts for about 75% of the original ore. The copper-molybdenum mixed coarse concentrate is separated from the copper-molybdenum mixed coarse concentrate using the pre-oxidation enhanced treatment method of the present invention, which specifically includes the following steps:

[0033] The prepared 3 mol / L hydrogen peroxide solution was mixed with the raw ore in a ratio of 2:1 and stirred for 10 minutes, and then washed with deionized water to obtain the experimental mineral. The experimental mineral was slurried with water to a solid particle mass concentration of 20%, and magnetic separation was performed using a SLon-100 periodic pulsating high-gradient magnetic separator. The background magnetic induction intensity of the magnetic separation was 1.6T, the pulsation frequency was 100r / min, and the slurry flow rate was 2L / min, to obtain copper rough concentrate and magnetic separation tailings; the copper rough concentrate was then subjected to a concentration operation to ensure that the pulsation frequency and slurry flow rate remained unchanged, and the concentration magnetic induction intensity was 1.4T, to obtain copper rough concentrate 1 and selected middlings; the selected middlings and rougher tailings were separated. The mixture was mixed and stirred, then filtered, dehydrated, and concentrated to a concentration of 30% for molybdenum flotation. The molybdenum flotation process consisted of one roughing, four finishing, and three scavenging steps. After stirring for 5 minutes, 100 g / t of sodium thioglycolate inhibitor was added. After stirring for 5 minutes, 100 g / t of kerosene collector was added. After stirring for 5 minutes, No. 2 oil was added as a frother. After mixing and stirring for 1 minute, aeration flotation was performed. The roughing flotation time was 5 minutes, and the scavenging and finishing flotation times were 3 minutes. The final product was a high-molybdenum concentrate and a high-copper concentrate. The experimental results are shown in Table 1.

[0034] Copper-molybdenum separation test results under the conditions of Example 1

[0035]

[0036] As shown in Table 1, the above process significantly enriches the copper in the magnetic concentrate, with a grade of 3.13% and a recovery rate of 78.72%. After the first roughing, three refining, and three sweeping process, the resulting flotation concentrate has a molybdenum grade of 49.01% and a molybdenum recovery rate of 96.62%.

[0037] Example 2

[0038] The molybdenum content of a copper-molybdenum mixed coarse concentrate is 6.73%, the copper content is 0.49%, and the other gangue minerals are mainly quartz (41%) and mica (20%). The -200 mesh size accounts for about 75% of the original ore. The copper-molybdenum mixed coarse concentrate is separated from the copper-molybdenum mixed coarse concentrate using the pre-oxidation enhanced treatment method of the present invention, which specifically includes the following steps:

[0039] The prepared 3 mol / L hydrogen peroxide solution was mixed with the raw ore in a ratio of 2:1 and stirred for 10 minutes, and then washed with deionized water to obtain the experimental mineral. The experimental mineral was slurried with water to a solid particle mass concentration of 20%, and magnetic separation was performed using a SLon-100 periodic pulsating high-gradient magnetic separator. The background magnetic induction intensity of the magnetic separation was 1.6T, the pulsation frequency was 100r / min, and the slurry flow rate was 2L / min, to obtain copper rough concentrate and magnetic separation tailings; the copper rough concentrate was then subjected to a concentration operation to ensure that the pulsation frequency and slurry flow rate remained unchanged, and the concentration magnetic induction intensity was 1.4T, to obtain copper rough concentrate 1 and selected middlings; the selected middlings and rougher tailings were separated. Mix evenly, stir, filter, dehydrate and concentrate to 30% concentration for molybdenum flotation operation; the molybdenum flotation process is one roughing, four fines and three scavenging. After stirring for 5 minutes, add the inhibitor sodium thioglycolate, the dosage is 100g / t, stir for 5 minutes, add the collector kerosene, the dosage is 100g / t, stir for 5 minutes, add the foaming agent No. 2 oil, mix and stir for 1 minute, and then perform aeration flotation; the roughing flotation time is 5 minutes, and the scavenging and concentrating flotation time is 3 minutes; finally, high molybdenum concentrate and high copper concentrate are obtained. The experimental results are shown in Table 2

[0040] Copper-molybdenum separation test results under the conditions of Example 2

[0041]

[0042] As shown in Table 2, the above process results in a significant enrichment of copper in the magnetic concentrate, with a grade of 3.01% and a recovery rate of 78.60%. After the first roughing, three refining, and three sweeping process, the resulting flotation concentrate has a molybdenum grade of 50.27% and a molybdenum recovery rate of 94.37%.

[0043] Practical Example 3

[0044] The molybdenum content of a copper-molybdenum mixed coarse concentrate is 6.46%, the copper content is 0.59%, and the other gangue minerals are mainly quartz (41%) and mica (21%). The -200 mesh size accounts for about 75% of the original ore. The copper-molybdenum mixed coarse concentrate is separated from the copper-molybdenum mixed coarse concentrate using the pre-oxidation enhanced treatment method of the present invention, which specifically includes the following steps:

[0045] 5% hydrogen peroxide solution was mixed with the raw ore in a ratio of 2:1 and stirred for 10 minutes, and then washed with distilled water to obtain the experimental mineral. The copper-molybdenum mixed rough concentrate was slurried with water to a solid particle mass concentration of 20%, and a SLon-100 periodic pulsating high-gradient magnetic separator was used for roughing operation. The background magnetic induction intensity was 1.6T, the pulsation frequency was 100r / min, and the slurry flow rate was 2L / min to obtain copper rough concentrate and magnetic separation tailings; the copper rough concentrate was subjected to a selection operation to ensure that the pulsation frequency and slurry flow rate remained unchanged, and the selection magnetic induction intensity was 1.4T to obtain copper rough concentrate 1 and selected middlings; the selected middlings were mixed with the roughing tailings. The precipitate was mixed evenly, stirred, filtered, dehydrated, and concentrated to a concentration of 30% for roughing molybdenum. The molybdenum flotation process consisted of one roughing, three finishing, and two scavenging steps. After stirring for 5 minutes, 100 g / t of sodium thioglycolate inhibitor was added. After stirring for 5 minutes, 100 g / t of kerosene collector was added. After stirring for 5 minutes, No. 2 oil was added as a frother. After mixing and stirring for 1 minute, aeration flotation was performed. The roughing flotation time was 5 minutes, and the scavenging and finishing flotation times were 3 minutes. The final product was a high-molybdenum concentrate and a high-copper concentrate. See Table 3.

[0046] Table 3 Copper-molybdenum separation test results under the conditions of actual embodiment 3

[0047]

[0048] As shown in Table 3, the above process significantly enriches the copper in the magnetic concentrate, with a grade of 3.54% and a recovery rate of 83.06%. After the first roughing, three refining, and three sweeping process, the resulting flotation concentrate has a molybdenum grade of 49.01% and a molybdenum recovery rate of 96.56%.

[0049] Comparative Example 1

[0050] The molybdenum content of a copper-molybdenum mixed coarse concentrate is 6.96%, the copper content is 0.59%, and the other gangue minerals are mainly quartz (41%) and mica (20%). The -200 mesh size accounts for about 75% of the original ore. The separation process of the copper-molybdenum mixed coarse concentrate is used to separate copper and molybdenum without pre-oxidation experiment. Specifically, the following steps are included:

[0051] The experimental mineral was slurried with water to a solid particle mass concentration of 20%, and magnetic separation was carried out using a SLon-100 periodic pulsating high gradient magnetic separator. The background magnetic induction intensity of the magnetic separation was 1.6T, the pulsation frequency was 100r / min, and the slurry flow rate was 2L / min, to obtain copper rough concentrate and magnetic separation tailings. The copper rough concentrate was then subjected to a concentration operation, ensuring that the pulsation frequency and slurry flow rate remained unchanged, and the concentration magnetic induction intensity was 1.4T, to obtain copper rough concentrate 1 and concentrated middlings. The concentrated middlings and rougher tailings were separated. The mixture was mixed and stirred, then filtered, dehydrated, and concentrated to a concentration of 30% for molybdenum flotation. The molybdenum flotation process consisted of one roughing, four finishing, and three scavenging steps. After stirring for 5 minutes, 100 g / t of sodium thioglycolate inhibitor was added. After stirring for 5 minutes, 100 g / t of kerosene collector was added. After stirring for 5 minutes, No. 2 oil was added as a frother. After mixing and stirring for 1 minute, aeration flotation was performed. The roughing flotation time was 5 minutes, and the scavenging and finishing flotation times were 3 minutes. The final product was a high-molybdenum concentrate and a high-copper concentrate. The experimental results are shown in Table 4.

[0052] Table 4 Copper-molybdenum separation test results under the conditions of Comparative Example 1

[0053]

[0054] As shown in Table 4, after the above process, the copper grade in the magnetic separation concentrate is 2.82%, and the recovery rate is 72.90%. After the one-roughing, three-fine, three-sweeping process, the molybdenum grade of the flotation concentrate is 37.29%, and the molybdenum recovery rate is 92.72%.

[0055] Comparative Example 2

[0056] The molybdenum content of a copper-molybdenum mixed coarse concentrate is 6.94%, the copper content is 0.37%, and the other gangue minerals are mainly quartz (41%) and mica (20%). The -200 mesh size accounts for about 75% of the original ore. The separation process of the present invention is used to separate copper and molybdenum from the copper-molybdenum mixed coarse concentrate, and a pre-oxidation experiment is carried out. The oxidation time is not in the preferred scheme, and the oxidation time is selected to be 1 hour. Specifically comprising the following steps:

[0057] The prepared 3 mol / L hydrogen peroxide solution was mixed with the raw ore in a ratio of 2:1 and stirred for 1 hour, and then washed with deionized water to obtain the experimental mineral. The experimental mineral was slurried with water to a solid particle mass concentration of 20%, and magnetic separation was performed using a SLon-100 periodic pulsating high-gradient magnetic separator. The background magnetic induction intensity of the magnetic separation was 1.6T, the pulsation frequency was 100r / min, and the slurry flow rate was 2L / min, to obtain copper rough concentrate and magnetic separation tailings; the copper rough concentrate was then subjected to a concentration operation to ensure that the pulsation frequency and slurry flow rate remained unchanged, and the concentration magnetic induction intensity was 1.4T to obtain copper rough concentrate 1 and selected middlings; the selected middlings and rougher tailings were separated. The mixture was mixed and stirred, then filtered, dehydrated, and concentrated to a concentration of 30% for molybdenum flotation. The molybdenum flotation process consisted of one roughing, four finishing, and three scavenging steps. After stirring for 5 minutes, 100 g / t of sodium thioglycolate inhibitor was added. After stirring for 5 minutes, 100 g / t of kerosene collector was added. After stirring for 5 minutes, No. 2 oil was added as a frother. After mixing and stirring for 1 minute, aeration flotation was performed. The roughing flotation time was 5 minutes, and the scavenging and finishing flotation times were 3 minutes. The final product was a high-molybdenum concentrate and a high-copper concentrate. The experimental results are shown in Table 4.

[0058] Table 5 Copper-molybdenum separation test results under the conditions of Comparative Example 2

[0059]

[0060] As shown in Table 5, after the above process, the copper grade in the magnetic separation concentrate is 1.83%, and the recovery rate is 70.65%. After the one-roughing, three-fine, three-sweeping process, the molybdenum grade of the flotation concentrate is 44.36%, and the molybdenum recovery rate is 90.83%.

[0061] Depend on Figure 2 It can be seen that with the change of oxidation degree, the magnetic properties of chalcopyrite and molybdenite have undergone significant changes, and the magnetic difference between the two has also changed accordingly. Therefore, the two minerals can be separated by pre-oxidation magnetic separation.

Claims

1. A pre-oxidation-magnetic-flotation combined beneficiation process for enhancing the separation of copper-molybdenum mixed concentrates, characterized in that: The following steps are included: Step (1): pre-oxidizing the copper-molybdenum mixed concentrate; stirring and mixing a certain concentration of oxidant solution with the mineral, filtering after the reaction is completed, and then washing the surface with deionized water to obtain the initial raw ore; Step (2): After the initial raw ore is slurried to form a slurry, it is added to a high gradient magnetic separator for magnetic separation. Under a certain magnetic field strength, two strong magnetic separations are performed to obtain a magnetic product, a non-magnetic product and a magnetically separated ore. The magnetic product is a copper concentrate. Step (3): Combine the magnetically separated ore and non-magnetic products into flotation. The flotation process adopts one roughing + three cleaning + three scavenging. In the roughing and scavenging, inhibitors, collectors and frothers are added in sequence. Only inhibitors are added to the cleaning, stirred evenly and then aeration is started for flotation separation. The flotation concentrate is molybdenum concentrate.

2. A pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In the step (1), 0.3 mol / L hydrogen peroxide solution and copper-molybdenum mixed concentrate are selected in a mass ratio of 2:1 to 1.5:1 and fused and stirred, and the oxidation time is selected to be 15-20 min.

3. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In step (2), during the primary magnetic separation process, the pulp concentration is adjusted to 20% to 30%, the water flow rate is 2L / min to 1.5L / min, the magnetic induction intensity is 1.7 to 1.5T, and the pulsation frequency is 100 to 120r / min.

4. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In step (2), during the secondary magnetic separation process, the pulp concentration is adjusted to 20% to 30%, the water flow rate is 2L / min to 1.5L / min, the magnetic induction intensity is 1.6 to 1.4T, and the pulsation frequency is 100 to 120r / min.

5. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In the step (3), the inhibitor in the roughing and scavenging processes is sodium thioglycolate, sodium sulfide, and sodium hydrosulfide in a mass ratio of (1:5 to 1:10), or sodium thioglycolate is used alone; the amount of sodium thioglycolate used in the roughing process in the combined inhibitor is 80 to 200 g / t; the amount of sodium thioglycolate used in the scavenging process in the combined inhibitor is 30 to 100 g / t.

6. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In the step (3), the collector used in the roughing and scavenging is one of kerosene and diesel or they are used in combination according to a mass ratio of (1:1 to 1:2), and the amount of kerosene in the combined collector is 100 to 300 g / t.

7. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In the step (3), the foaming agent in the roughing process is at least one of terpineol, methyl isobutyl carbinol, and diethyl phthalate, and the amount of the foaming agent added is 50 to 100 g / t.

8. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In the step (3), the inhibitor in the beneficiation process is sodium thioglycolate, sodium sulfide, and sodium hydrosulfide in a mass ratio of (1:5 to 1:10) or sodium thioglycolate is used alone; the amount of crude sodium thioglycolate in the combined inhibitor is 50 to 100 g / t.

9. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: In the step (3), the roughing flotation time is 8 to 11 minutes, and the cleaning and scavenging time is 5 to 8 minutes.

10. The pre-oxidation-magnetic-flotation combined beneficiation process for enhancing separation of copper-molybdenum mixed concentrate according to claim 1, characterized in that: The copper-molybdenum mixed concentrate has a particle size of -200 mesh, with a proportion greater than 70%, a molybdenum grade of 6%-9%, and a copper grade ratio greater than 0.3%.

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