Suspension roasting pretreatment flotation separation method for micro-fine particle molybdenum-copper bulk concentrate

Abstract

The invention discloses a method for strengthening flotation separation through micro-fine particle molybdenum-copper bulk concentrate suspension roasting pretreatment, and belongs to the technical field of mineral processing. According to the method, firstly, micro-fine-particle molybdenum-copper bulk concentrate is treated through a suspension oxidizing roasting-flotation technology, the problem that separation is difficult due to the fact that the particle size is fine and surface residual agents are complex is effectively solved, and efficient recycling of micro-fine-particle-grade molybdenite and chalcopyrite is achieved; by accurately controlling roasting parameters and utilizing the surface chemical and crystal structure characteristic difference of the target mineral, the surface oxidation degree and residual reagent removal of the target mineral are accurately regulated and controlled, and favorable conditions are created for subsequent efficient flotation separation; the process is good in production continuity, is operated at a lower temperature, is energy-saving and environment-friendly, remarkably weakens the agglomeration phenomenon of particles compared with a traditional roasting oxidation pretreatment method, can directly enter flotation separation operation after the pretreated material is cooled, and has obvious advantages in the aspects of energy consumption, environmental protection, large-scale equipment and industrial implementation.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a method for flotation separation of fine-grained molybdenum-copper mixed concentrate after suspension roasting pretreatment. Background Technology

[0002] Statistics show that nearly 75% of the world's copper and 50% of its molybdenum are recovered from copper-molybdenum ore, mainly from porphyry and skarn deposits. These ores are characterized by low grade, fine grain size, tightly intergrowth of copper-molybdenum minerals, similar floatability of molybdenite and chalcopyrite, and difficulty in reactivating chalcopyrite after inhibition, making separation of the two minerals extremely difficult. Therefore, efficient separation of copper-molybdenum is a key issue in mineral processing, and researchers both domestically and internationally have conducted extensive research in this field, achieving certain results.

[0003] Molybdenum-copper ores are generally separated using flotation methods, mainly including mixed flotation, preferential flotation, and equal flotation. Mixed flotation is currently the most widely used process in industry, which involves mixing molybdenum and copper to obtain a mixed molybdenum-copper concentrate, and then performing separate flotation to obtain molybdenum concentrate and copper concentrate. However, due to the similar floatability, fine particle size, and complex surface residual reagents of chalcopyrite and molybdenite, the separation effect of molybdenum and copper is relatively poor.

[0004] In the molybdenum-copper separation flotation stage, there are two schemes: copper suppression for molybdenum flotation and molybdenum suppression for copper flotation. Since molybdenite has high floatability while chalcopyrite has relatively low floatability, the copper suppression for molybdenum flotation process is generally adopted. Based on the analysis of the difficulties in molybdenum-copper flotation separation, a pretreatment stage is required before separation. On the one hand, it is necessary to remove flotation reagents adsorbed on the mineral surface and remaining in the pulp to create favorable conditions for molybdenum-copper separation; on the other hand, because molybdenum and copper have similar floatability, it is necessary to increase the difference in floatability between the molybdenum and copper minerals to create favorable conditions for separation. Currently, research on pretreatment processes for molybdenum-copper mixed concentrates at home and abroad mainly includes mechanical derelictation, desorption derelictation, oxidative derelictation, microwave activation pretreatment, and oxidative pretreatment. Among these, oxidative pretreatment can be achieved through heating or roasting. Theoretically, heating is an effective method for removing reagents. Heating (or roasting) the molybdenum-copper mixed concentrate aims to decompose the collectors on the surface of minerals such as chalcopyrite and pyrite, destroy the hydrophobic film, and evaporate the frothers and residual reagents in the pulp. Meanwhile, the oxidation of copper mineral surfaces reduces their floatability, allowing for a decrease in the amount of depressant needed, while having minimal impact on molybdenite, which retains good floatability, thus achieving separation. Studies have shown that copper sulfide minerals slowly oxidize when exposed to the atmosphere, and the collectors used in molybdenum-copper mixed flotation have low boiling points (mostly below 180°C), making them easy to remove at lower temperatures. Therefore, oxidation and heating methods provide new approaches for the pretreatment of molybdenum-copper mixed concentrates.

[0005] Currently, the main heating methods include heaters, roasting, and steam blowing. It has been confirmed that approximately 40% of molybdenum-copper beneficiation plants worldwide employ heat treatment, which not only reduces sodium sulfide usage but also significantly improves beneficiation indicators. However, traditional heating or roasting equipment is energy-intensive and unsuitable for processing fine-particle raw materials, resulting in less than ideal pretreatment effects. Suspension oxidative roasting is not yet applied in this field and remains in the research stage. However, based on pretreatment methods for molybdenum-copper mixed concentrates and theoretical research on molybdenite and chalcopyrite, suspension oxidative roasting technology is feasible for the pretreatment of molybdenum-copper mixed concentrates and has substantial mechanistic support. Therefore, researching suspension roasting pretreatment to enhance the separation and flotation of molybdenum-copper mixed concentrates is of great significance for improving the quality and recovery rate of molybdenum and copper concentrates and reducing production costs. Summary of the Invention

[0006] To overcome the problems of high energy consumption and poor separation effect caused by traditional heating roasting pretreatment methods, which are unsuitable for fine-particle molybdenum-copper mixed concentrates, this invention provides a method for flotation separation of fine-particle molybdenum-copper mixed concentrates through suspension roasting pretreatment. This method achieves efficient decanting and precise surface control of fine-particle minerals through suspension oxidation roasting, thereby enhancing the flotation separation of molybdenum and copper.

[0007] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a method for flotation separation of fine-particle molybdenum-copper mixed concentrate after suspension roasting pretreatment, comprising the following steps: Step 1: The molybdenum-copper mixed concentrate is thickened and filtered to obtain a filter cake, wherein the moisture content of the filter cake is ≤20%; Step 2: The filter cake obtained in Step 1 is subjected to suspension oxidation roasting pretreatment under an oxidizing atmosphere, wherein the oxidizing atmosphere is a mixture of air and nitrogen. Step 3: After oxidation is complete, the roasting product is cooled and discharged from the roasting system to obtain cooled molybdenum-copper mixed concentrate; Step 4: The cooled molybdenum-copper mixed concentrate obtained in Step 3 is subjected to slurry conditioning, and then molybdenum-copper separation flotation is carried out to obtain molybdenum concentrate and copper concentrate.

[0008] A further improvement of the present invention is that, before step 1, a grinding operation is included, in which the molybdenum-copper mixed concentrate obtained by flotation is ground to obtain a grinding product; the grinding slurry concentration is 40%~70%, and the grinding fineness is -0.037mm particle size content ≥85%.

[0009] A further improvement of the present invention is that the molybdenum-copper mixed concentrate includes molybdenite and chalcopyrite.

[0010] A further improvement of the present invention is that, in step 2, air accounts for 40% to 70% of the total gas volume in the air-nitrogen mixture, and the gas is introduced through the bottom of the oxidation reactor. The temperature of the suspension oxidation roasting pretreatment is 250~300℃, and the oxidation roasting time is 30~90min.

[0011] A further improvement of the present invention is that, in step 3, the cooling method is air cooling, and the waste heat is recovered and returned to the roasting system.

[0012] A further improvement of the present invention is that, in step 4, the obtained cooled molybdenum-copper mixed concentrate is subjected to slurry conditioning treatment, wherein the slurry conditioning treatment is carried out in a flotation cell; flotation reagents are added during the molybdenum-copper separation flotation operation, and the flotation reagents include dispersants, inhibitors, collectors and frothers.

[0013] A further improvement of the present invention is that the dispersant is sodium hexametaphosphate and water glass.

[0014] A further improvement of the present invention is that the inhibitor is at least one selected from sodium sulfide, sodium hydrosulfide, and sodium thioglycolate.

[0015] A further improvement of the present invention is that the collector is kerosene or diesel oil; and the foaming agent is pine oil.

[0016] A further improvement of the present invention is that, in step 4, the molybdenum-copper separation flotation operation includes one roughing, two to four cleaning, and two to four scavenging, wherein the middlings from the cleaning and scavenging are returned to the previous stage operation in sequence.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for suspension roasting pretreatment and flotation separation of fine-grained molybdenum-copper mixed concentrate. This method employs a suspension oxidation roasting-flotation process to treat the fine-grained molybdenum-copper mixed concentrate, effectively solving the separation difficulties caused by its fine particle size and complex surface residual reagents. It achieves efficient recovery of fine-grained molybdenite and chalcopyrite. By precisely controlling the roasting parameters and utilizing the differences in surface chemistry and crystal structure characteristics of the target minerals, the degree of oxidation of the target mineral surface and the removal of residual reagents are precisely controlled, creating favorable conditions for subsequent efficient flotation separation. This process offers good production continuity, operates at lower temperatures, and is energy-saving and environmentally friendly. Compared with traditional roasting oxidation pretreatment methods, it significantly reduces particle agglomeration. The pretreated material can be directly fed into the flotation separation operation after cooling, demonstrating significant advantages in energy consumption, environmental protection, and the large-scale and industrial implementation of equipment. Attached Figure Description

[0018] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components of the invention.

[0019] Figure 1 This is a process flow diagram of a suspended roasting pretreatment-flotation separation method for molybdenum-copper mixed concentrate according to the present invention. Detailed Implementation

[0020] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0022] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0023] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0024] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0025] like Figure 1 As shown, the present invention provides a method for flotation separation of fine-particle molybdenum-copper mixed concentrate after suspension roasting pretreatment, comprising the following steps: Step 1: The molybdenum-copper mixed concentrate is thickened and filtered to obtain a filter cake, wherein the moisture content of the filter cake is ≤20%; The molybdenum-copper mixed concentrate is mainly obtained by flotation of porphyry molybdenum-copper ore, or it can be obtained by enriching intermediate products from molybdenum beneficiation plants. The main minerals are molybdenite and chalcopyrite, followed by a small amount of pyrite, and gangue is rare. The molybdenum-copper intercalation particle size in the molybdenum-copper concentrate is relatively fine, and the content and distribution rate of molybdenum and copper in the fine particles after grinding are relatively high.

[0026] Step 2: The filter cake obtained in Step 1 is subjected to suspension oxidation roasting pretreatment under an oxidizing atmosphere, wherein the oxidation roasting temperature is 250~300℃ and the oxidation roasting time is 30~90min; the oxidizing atmosphere is a mixture of air and nitrogen, wherein air accounts for 40%~70% of the total gas volume, and the gas is introduced through the bottom of the oxidation reactor. As a preferred option, a small amount of SO2 is generated after the molybdenum-copper mixed concentrate is pretreated by suspension oxidation roasting. The generated SO2 is then used for desulfurization and sulfur fixation operations.

[0027] Step 3: After oxidation, the roasted product is cooled by air cooling and discharged from the roasting system to obtain cooled molybdenum-copper mixed concentrate. Waste heat is recovered during the cooling process and returned to the roasting system, thus achieving the recycling of waste heat.

[0028] Step 4: The cooled molybdenum-copper mixed concentrate obtained in Step 3 is subjected to slurry conditioning in a flotation cell, and flotation reagents are added to carry out molybdenum-copper separation flotation operation. The molybdenum-copper separation flotation operation includes 1 roughing, 2 to 4 cleaning (referred to as Cleaning I, Cleaning II, etc.) and 2 to 4 scavenging (referred to as Scavenging I, Scavenging II, etc.). The middlings from the cleaning and scavenging are returned to the previous stage operation in sequence, and then molybdenum concentrate and copper concentrate are obtained. The flotation reagents include dispersants, inhibitors, collectors, and frothers; wherein the dispersants are sodium hexametaphosphate and water glass; the inhibitors are sodium sulfide, sodium hydrosulfide, or sodium mercaptoacetate; the collectors are kerosene or diesel oil; and the frothers are pine oil.

[0029] As a preferred embodiment, before step 1, a grinding operation may be included, in which the molybdenum-copper mixed concentrate obtained by flotation is ground to obtain a grinding product, wherein the grinding slurry concentration is 40%~70% and the grinding fineness is -0.037mm particle size content ≥85%.

[0030] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0031] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0032] The suspension oxidation roasting system used in the following examples is a suspension oxidation roasting furnace, and the equipment specifications can be customized according to the actual processing capacity.

[0033] Example 1 This embodiment uses a molybdenum-copper mixed concentrate from Inner Mongolia Autonomous Region, with a molybdenum grade of 20.34% and a copper grade of 14.61%. The main minerals in the molybdenum-copper mixed concentrate are molybdenite and chalcopyrite, followed by a small amount of pyrite, and gangue is rare. The molybdenum and copper particles in the molybdenum-copper concentrate are relatively fine, with 60% of the particles being -0.037 mm in size, requiring regrinding to improve the degree of liberation.

[0034] A method for separation and flotation of molybdenum-copper mixed concentrate through suspension roasting pretreatment includes the following steps: Step 1: The molybdenum-copper mixed concentrate obtained by flotation is subjected to grinding to obtain the grinding product, wherein the grinding pulp concentration is 60% and the grinding fineness is -0.037mm particle size content is 90%; Step 2: The ground product is thickened and filtered to obtain a filter cake with a moisture content of 15%. Step 3: The filter cake obtained in Step 2 is fed into the suspension oxidation roasting system using a screw feeder. The roasting temperature is 280℃, the roasting time is 50min, and the oxidation atmosphere is a mixture of 50% air and 50% nitrogen to obtain the roasted product. Step 4: After oxidation is complete, the roasting product is cooled and discharged from the roasting system to obtain cooled molybdenum-copper mixed concentrate. Step 5: Add the cooled molybdenum-copper mixed concentrate to the flotation cell for stirring and slurry preparation. After slurry preparation, add flotation reagents to carry out molybdenum-copper separation flotation operation. The separation flotation process consists of one roughing, three cleaning, and three scavenging operations. The dispersants in the flotation reagents are sodium hexametaphosphate and water glass, the depressant is sodium mercaptoacetate, the collector is kerosene, and the frother is pine oil. The roughing process only adds the collector and frother, the first cleaning process adds the depressant, collector, and frother, the second cleaning process only adds the depressant, and the third cleaning process is a blank cleaning. The first scavenging process adds the collector and frother, the second scavenging process adds the collector and frother, and the third scavenging process only adds the collector. The middlings from the cleaning and scavenging processes of the separation flotation operation are returned to the previous operation in sequence, ultimately yielding molybdenum concentrate and copper concentrate.

[0035] The results of the mineral processing test are shown in Table 1 below. Table 1. Mineral processing indicators of Example 1 of the present invention

[0036] Comparative Example 1 This comparative example uses a molybdenum-copper mixed concentrate from Inner Mongolia Autonomous Region, with a molybdenum grade of 20.34% and a copper grade of 14.61%. The main minerals in the molybdenum-copper mixed concentrate are molybdenite and chalcopyrite, followed by a small amount of pyrite, and gangue is rare. The molybdenum and copper particles in the concentrate are relatively fine, with -0.037mm particles accounting for 60%, requiring regrinding to improve the degree of liberation.

[0037] A method for separation and flotation of molybdenum-copper mixed concentrate through suspension roasting pretreatment includes the following steps: Step 1: The molybdenum-copper mixed concentrate obtained by flotation is subjected to grinding to obtain the grinding product, wherein the grinding pulp concentration is 60% and the grinding fineness is -0.037mm particle size content is 90%; Step 2: Add the ground product to the flotation cell for stirring and slurry preparation. After slurry preparation, add flotation reagents to carry out molybdenum-copper separation flotation operation. The separation flotation process consists of one roughing, three cleaning, and three scavenging operations. The dispersants in the flotation reagents are sodium hexametaphosphate and water glass, the depressant is sodium mercaptoacetate, the collector is kerosene, and the frother is pine oil. The roughing process only adds the collector and frother, the first cleaning process adds the depressant, collector, and frother, the second cleaning process only adds the depressant, and the third cleaning process is a blank cleaning. The first scavenging process adds the collector and frother, the second scavenging process adds the collector and frother, and the third scavenging process only adds the collector. The middlings from the cleaning and scavenging processes of the separation flotation operation are returned to the previous operation in sequence, ultimately yielding molybdenum concentrate and copper concentrate.

[0038] The experimental results showed that the separation effect of molybdenum and copper was not good. The results showed that the Mo grade in the molybdenum concentrate was 28.78% and the Cu grade was 10.56%, while the Mo grade in the copper concentrate was 15.34% and the Cu grade was 17.46%.

[0039] Example 2 This embodiment uses a molybdenum-copper mixed concentrate from Shaanxi Province, with a molybdenum grade of 21.23% and a copper grade of 14.33%. The main minerals in the molybdenum-copper mixed concentrate are molybdenite and chalcopyrite, with gangue being rare. The molybdenum and copper particles in the concentrate are finely intercalated, and the content of particles with a size of -0.037 mm is 90%.

[0040] A method for separation and flotation of molybdenum-copper mixed concentrate through suspension roasting pretreatment includes the following steps: Step 1: The molybdenum-copper mixed concentrate obtained by flotation is thickened and filtered to obtain a filter cake with a moisture content of 16%. Step 2: The filter cake obtained in Step 1 is fed into the suspension oxidation roasting system using a screw feeder. The roasting temperature is 260℃, the roasting time is 40min, and the oxidation atmosphere is a mixture of 60% air and 40% nitrogen to obtain the roasted product. Step 3: After oxidation, the roasted product is cooled and discharged from the roasting system to obtain cooled molybdenum-copper mixed concentrate. Step 4: Add the cooled molybdenum-copper mixed concentrate to the flotation cell for stirring and slurry preparation. After slurry preparation, add flotation reagents to carry out molybdenum-copper separation flotation operation. The separation flotation process consists of one roughing stage, four cleaning stages, and two scavenging stages. The dispersants in the flotation reagents are sodium hexametaphosphate and water glass, the depressants are sodium mercaptoacetate and sodium sulfide, the collector is kerosene, and the frother is pine oil. The roughing stage only adds the collector and frother, the first cleaning stage adds the depressant, collector, and frother, the second cleaning stage only adds the depressant, and the third cleaning stage is a blank cleaning. The first scavenging stage adds the collector and frother, the second scavenging stage adds the collector and frother, and the third scavenging stage only adds the collector. The middlings from the cleaning and scavenging stages of the separation flotation process are returned to the previous stage in sequence, ultimately yielding molybdenum concentrate and copper concentrate.

[0041] The results of the mineral processing test are shown in Table 2 below:

[0042] Comparative Example 2 This embodiment uses a molybdenum-copper mixed concentrate from Shaanxi Province, with a molybdenum grade of 21.23% and a copper grade of 14.33%. The main minerals in the molybdenum-copper mixed concentrate are molybdenite and chalcopyrite, with gangue being rare. The molybdenum and copper particles in the concentrate are finely intercalated, and the content of particles with a size of -0.037 mm is 90%.

[0043] A method for separation and flotation of molybdenum-copper mixed concentrate through suspension roasting pretreatment includes the following steps: The molybdenum-copper mixed concentrate obtained by flotation is added to the flotation cell for stirring and slurry preparation. After slurry preparation, 800g / t activated carbon is added and stirred for 10min to remove the reagents. Then, flotation reagents are added to carry out molybdenum-copper separation flotation operation. The separation flotation process consists of one roughing stage, four cleaning stages, and two scavenging stages. The dispersants in the flotation reagents are sodium hexametaphosphate and water glass, the depressants are sodium mercaptoacetate and sodium sulfide, the collector is kerosene, and the frother is pine oil. The roughing stage only adds the collector and frother, the first cleaning stage adds the depressant, collector, and frother, the second cleaning stage only adds the depressant, and the third cleaning stage is a blank cleaning. The first scavenging stage adds the collector and frother, the second scavenging stage adds the collector and frother, and the third scavenging stage only adds the collector. The middlings from the cleaning and scavenging stages of the separation flotation process are returned to the previous stage in sequence, ultimately yielding molybdenum concentrate and copper concentrate.

[0044] The experimental results showed that the separation effect of molybdenum and copper was not good. The results showed that the Mo grade in the molybdenum concentrate was 27.34% and the Cu grade was 11.31%, while the Mo grade in the copper concentrate was 16.56% and the Cu grade was 18.12%.

[0045] In summary, the fine-particle molybdenum-copper mixed concentrate, after suspension roasting pretreatment, exhibits good molybdenum-copper flotation separation, yielding qualified molybdenum and copper concentrates. This indicates that the suspension roasting pretreatment process not only eliminates residual reagents on the surface of the molybdenum-copper mixed concentrate from the flotation process but also expands the floatability differences between molybdenum and copper. Fine-particle molybdenum-copper mixed concentrates that have not undergone pretreatment or activated carbon de-removal show poor molybdenum-copper flotation separation, failing to yield qualified molybdenum and copper concentrates.

[0046] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting, characterized in that, Includes the following steps: Step 1: The molybdenum-copper mixed concentrate is thickened and filtered to obtain a filter cake, wherein the moisture content of the filter cake is ≤20%; Step 2: The filter cake obtained in Step 1 is subjected to suspension oxidation roasting pretreatment under an oxidizing atmosphere, wherein the oxidizing atmosphere is a mixture of air and nitrogen. Step 3: After oxidation is complete, the roasting product is cooled and discharged from the roasting system to obtain cooled molybdenum-copper mixed concentrate; Step 4: The cooled molybdenum-copper mixed concentrate obtained in Step 3 is subjected to slurry conditioning, and then molybdenum-copper separation flotation is carried out to obtain molybdenum concentrate and copper concentrate.

2. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 1, characterized in that, Before step 1, a grinding operation is also included, in which the molybdenum-copper mixed concentrate obtained by flotation is ground to obtain a grinding product; the grinding slurry concentration is 40%~70%, and the grinding fineness is -0.037mm particle size content ≥85%.

3. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 1, characterized in that, The molybdenum-copper mixed concentrate includes molybdenite and chalcopyrite.

4. The method for suspension roasting pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate according to claim 1, characterized in that, In step 2, air accounts for 40% to 70% of the total gas volume in the air-nitrogen mixture, and the gas is introduced through the bottom of the oxidation reactor. The temperature of the suspension oxidation roasting pretreatment is 250~300℃, and the oxidation roasting time is 30~90min.

5. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 1, characterized in that, In step 3, the cooling method is air cooling, and the waste heat is recovered and returned to the roasting system.

6. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 1, characterized in that, In step 4, the obtained cooled molybdenum-copper mixed concentrate is subjected to slurry conditioning, which is carried out in a flotation cell; flotation reagents are added during the molybdenum-copper separation flotation operation, including dispersants, inhibitors, collectors and frothers.

7. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 6, characterized in that, The dispersant is sodium hexametaphosphate and water glass.

8. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 6, characterized in that, The inhibitor is at least one of sodium sulfide, sodium hydrosulfide, and sodium thioglycolate.

9. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 6, characterized in that, The collector is kerosene or diesel oil; the foaming agent is pine oil.

10. The method for pretreatment and flotation separation of fine-particle molybdenum-copper mixed concentrate by suspension roasting according to claim 1, characterized in that, In step 4, the molybdenum-copper separation flotation operation includes one roughing flotation, two to four cleaning flotations, and two to four scavenging flotations, wherein the middlings from the cleaning and scavenging flotations are returned to the previous stage of the operation in sequence.

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