Combined separation method for lead-zinc-silver ore associated with iron and manganese

Abstract

The invention provides a combined separation method for lead-zinc-silver ore associated with iron and manganese, belongs to the field of ore dressing, and realizes effective separation and recovery of different metals in the lead-zinc-silver ore associated with iron and manganese through processes of raw ore crushing, wet grinding, bulk flotation and magnetic separation. According to the flotation-magnetic separation combined technology, a conventional flotation reagent is adopted, the reagent cost is reduced, and meanwhile silver-containing minerals and sulfide minerals are effectively collected. According to the method, a silver-lead-zinc preferential flotation process and a subsequent separation step are omitted, and the reagent cost and the mineral separation cost are remarkably reduced. The device is high in adaptability and easy and convenient to operate, the regulation and control difficulty of a production line and the operation difficulty of workers are reduced, and the loss of silver in the separation process is avoided. By simplifying the process and improving the recovery rate, the method is beneficial to reducing environmental pollution and promoting effective utilization of resources. Aiming at the associated iron-manganese-lead-zinc-silver ore with complex components, the flotation-magnetic combined process can effectively separate various valuable metals and impurity minerals, and the ore dressing efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of ore dressing, and in particular to a method for combined separation of lead-zinc-silver ores with associated iron and manganese. Background Art

[0002] Lead-zinc-silver ores with associated iron and manganese contain not only the main metal elements such as lead, zinc, and silver, but also other metal elements such as iron and manganese. These elements exist in different mineral forms in the ore, such as galena, sphalerite, silver minerals, magnetite, limonite, etc. This diversity of components requires the mineral processing process to be sorted according to different mineral characteristics. There is often a complex symbiotic relationship between various minerals. For example, lead-zinc minerals and iron-manganese minerals may coexist closely, making it difficult to achieve effective separation by simple physical or chemical methods. In addition, the mineral particle sizes in the ore are uneven, and some minerals are distributed in a fine-grained impregnation state, which further increases the difficulty of mineral processing.

[0003] The current process of lead-zinc-silver ore beneficiation with associated iron and manganese is silver-lead priority flotation-iron-manganese magnetic separation and silver-lead-zinc mixed flotation and separation-manganese-iron magnetic separation. In order to ensure the quality of lead concentrate and the floating of some easily floating silver-containing minerals, the collector used in the silver-lead priority flotation operation is often a combination of ethyl xanthate + butyl ammonium black medicine. Although it has a certain collection effect on pyrite, the carrier mineral of silver, it does not maximize the recovery of pyrite, resulting in a part of silver-containing pyrite not floating. The zinc flotation operation adopts the sulfur-suppressing zinc flotation process, which uses lime to suppress pyrite, and the silver-containing pyrite is also suppressed, so the silver recovery rate is affected. In order to solve the problem of difficult recovery of silver-lead-zinc ore, the traditional process of silver-lead-zinc mixed flotation followed by separation and then manganese-iron magnetic separation has achieved mineral enrichment to a certain extent, but it also exposes significant limitations and challenges. The mixed flotation-separation process not only greatly increases the complexity of the operation and increases the difficulty of regulating the production line, but also directly leads to a sharp increase in the cost of reagents due to the joint use of multiple flotation reagents. More importantly, it is often difficult to accurately control the separation efficiency of each component during the processing process, especially the recovery of silver. It is very easy for silver to be lost in multiple links, which in turn has a significant impact on the overall economic benefits.

[0004] In view of this, it is necessary to design an improved method for the combined separation of lead-zinc-silver ores with associated iron and manganese to solve the above problems. Summary of the invention

[0005] In view of the technical problems existing in the background technology, the present application provides a combined separation method for lead-zinc-silver ores with associated iron and manganese, which adopts a flotation-magnetic separation combined process. Under the synergistic effect of mineral processing agents and process flow, efficient recovery of silver, iron and manganese is achieved, the recovery rate of silver metal is improved, and lead and zinc can be comprehensively recovered at the same time, solving the problems of complex conventional process flow, high mineral processing cost and difficulty in maximizing the recovery of target minerals.

[0006] To achieve the above object, the present invention provides a combined separation method of lead-zinc-silver ore with associated iron and manganese, comprising the following steps:

[0007] S1. Crushing the raw ore to -2mm, then wet grinding, grinding the ore to a particle size of -0.074mm with a mass content of 85-89%, adding water to adjust the slurry concentration to a predetermined range;

[0008] S2. The slurry obtained in step S1 is subjected to mixed roughing of silver, lead and zinc to obtain a mixed roughing concentrate and a mixed roughing tailings; the mixed roughing concentrate is subjected to four mixed selections to obtain a mixed concentrate; the mixed roughing tailings are subjected to two mixed scavengings to obtain a mixed tailings;

[0009] S3. The mixed tailings obtained in step S2 are subjected to weak magnetic roughing to obtain weak magnetic roughing concentrate and weak magnetic roughing tailings; the weak magnetic roughing concentrate is subjected to a regrinding process, and then subjected to two weak magnetic concentrations to obtain a weak magnetic concentration concentrate; the middlings obtained from the two weak magnetic concentrations are subjected to a third weak magnetic concentration, and the concentrate obtained is combined with the weak magnetic concentration concentrate to obtain an iron concentrate, and the third weak magnetic concentration tailings are combined with the weak magnetic roughing tailings to obtain an iron concentration tailings;

[0010] S4. The iron tailings obtained in step S3 are subjected to strong magnetic roughing to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings; the strong magnetic roughing concentrate is subjected to a regrinding process, and then subjected to two strong magnetic concentrations to obtain a strong magnetic concentration concentrate; the middlings obtained from the two strong magnetic concentrations are subjected to a third strong magnetic concentration, and the concentrate obtained is combined with the strong magnetic concentration concentrate to obtain a manganese concentrate, and the tailings from the third strong magnetic concentration are combined with the strong magnetic roughing tailings to obtain tailings.

[0011] As a further improvement of the present invention, in step S1, the slurry concentration is 30-40%.

[0012] As a further improvement of the present invention, in step S2, the mixed roughing reagents are 40-60 g / t of copper sulfate, 50-70 g / t of butyl xanthate, 15-25 g / t of butyl ammonium black powder, and 20-40 g / t of 2# oil.

[0013] Furthermore, the reagents for the first mixed sweep are 20-40 g / t of butyl xanthate and 5-15 g / t of butyl ammonium black powder; and the reagents for the second mixed sweep are 10-20 g / t of butyl xanthate and 3-8 g / t of butyl ammonium black powder.

[0014] The mixed selected middlings are returned to the previous operation in sequence and level by level; the mixed scavenged concentrates are returned to the previous operation in sequence.

[0015] As a further improvement of the present invention, in step S3, the magnetic field strength of the weak magnetic roughing and the weak magnetic concentrating is 900-1100 GS.

[0016] The regrinding process is to regrind the weak magnetic rougher concentrate to a particle mass content of 88-92% at a particle size of -0.025 mm.

[0017] As a further improvement of the present invention, in step S4, the magnetic field strength of the strong magnetic roughing is 9000-12000 GS.

[0018] The regrinding process is to regrind the strong magnetic roughing concentrate to a particle mass content of 93-96% at a particle size of -0.025 mm.

[0019] The magnetic field strength of the first strong magnetic selection is 7000-9000GS, the magnetic field strength of the second strong magnetic selection is 5000-7000GS, and the magnetic field strength of the third strong magnetic selection is 4000-6000GS.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides a combined separation method for lead-zinc-silver ores with associated iron and manganese, which realizes effective separation and recovery of different metals in associated iron-manganese-lead-zinc-silver ores by crushing the raw ore, wet grinding, mixed flotation and magnetic separation processes. The present invention adopts a combined flotation-magnetic separation beneficiation process, and under the synergistic effect of beneficiation reagents and beneficiation processes, achieves efficient recovery of silver, iron and manganese, improves the recovery rate of silver metal, and can comprehensively recover lead and zinc at the same time, solving the problems of complex conventional beneficiation process, high beneficiation cost, and difficulty in maximizing the recovery of target minerals.

[0022] The present invention directly uses conventional flotation agents such as copper sulfate, butyl xanthate, butyl ammonium black, and 2# oil to recover silver, lead, and zinc, which not only controls the cost of flotation agents, but also has a strong capture effect on most sulfide minerals such as pyrite. Silver-containing minerals, silver-containing pyrite, galena, sphalerite, etc. all float into the concentrate product, achieving the maximum recovery of sulfide ores. Although this process has a large concentrate yield and the lead and zinc grade is difficult to guarantee, the silver recovery rate of the mixed flotation process is higher than that of the superior flotation process, avoiding the complex process of subsequent separation of silver, lead, and zinc or preferential flotation of silver, lead, and zinc in the conventional process. The process has strong on-site adaptability, reduces the difficulty of regulating and controlling the on-site production line and the difficulty of workers' operation, and avoids the loss of silver metal in the separation process, achieving the maximum recovery of precious metal silver.

[0023] After comparing the economic benefit calculation with other process flows, the present invention takes silver as the main target concentrate product in sulfide ore, cancels the silver-lead-zinc priority flotation process and the subsequent separation of silver, lead and zinc, avoids the combined use of multiple flotation agents during flotation separation, and directly leads to the problem of a sharp increase in agent costs, thereby greatly controlling the ore dressing cost.

[0024] When processing ores such as lead-zinc-silver ores with associated iron and manganese, the present invention adopts a flotation-magnetic combined process for mineral separation, which can more effectively meet the mineral separation needs of such complex ores due to their complex composition and the presence of multiple valuable metals and impurity minerals, and realizes the effective separation of multiple minerals. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a schematic diagram of the combined separation method of lead-zinc-silver ore with associated iron and manganese in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0029] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] The existing mineral processing technology is difficult to effectively separate lead, zinc and silver minerals associated with iron and manganese, resulting in low recovery rate and waste of resources. The complex mixed flotation separation process increases the difficulty of operation and production cost. At the same time, the reagent cost is high and the separation efficiency is difficult to accurately control.

[0031] In order to solve the technical problems of complex mineral processing procedures, high mineral processing costs, and difficulty in maximizing the recovery of target minerals, the present application provides a method for the combined separation of lead, zinc, and silver ores with associated iron and manganese, wherein, by adopting a combined flotation-magnetic separation process, under the synergistic effect of mineral processing agents and process flow, efficient recovery of silver, iron, and manganese is achieved, the recovery rate of silver metal is improved, and lead and zinc can be comprehensively recovered at the same time.

[0032] The present application provides a method for the combined separation of lead-zinc-silver ores associated with iron and manganese, comprising the following steps:

[0033] S1. Crushing the raw ore to -2mm, then wet grinding, grinding the ore to a particle size of -0.074mm with a mass content of 85-89%, adding water to adjust the slurry concentration to a predetermined range;

[0034] S2. The slurry obtained in step S1 is subjected to mixed roughing of silver, lead and zinc to obtain a mixed roughing concentrate and a mixed roughing tailings; the mixed roughing concentrate is subjected to four mixed selections to obtain a mixed concentrate; the mixed roughing tailings are subjected to two mixed scavengings to obtain a mixed tailings;

[0035] S3. The mixed tailings obtained in step S2 are subjected to weak magnetic roughing to obtain weak magnetic roughing concentrate and weak magnetic roughing tailings; the weak magnetic roughing concentrate is subjected to a regrinding process, and then subjected to two weak magnetic concentrations to obtain a weak magnetic concentration concentrate; the middlings obtained from the two weak magnetic concentrations are subjected to a third weak magnetic concentration, and the concentrate obtained is combined with the weak magnetic concentration concentrate to obtain an iron concentrate, and the third weak magnetic concentration tailings are combined with the weak magnetic roughing tailings to obtain an iron concentration tailings;

[0036] S4. The iron tailings obtained in step S3 are subjected to strong magnetic roughing to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings; the strong magnetic roughing concentrate is subjected to a regrinding process, and then subjected to two strong magnetic concentrations to obtain a strong magnetic concentration concentrate; the middlings obtained from the two strong magnetic concentrations are subjected to a third strong magnetic concentration, and the concentrate obtained is combined with the strong magnetic concentration concentrate to obtain a manganese concentrate, and the tailings from the third strong magnetic concentration are combined with the strong magnetic roughing tailings to obtain tailings.

[0037] Through the fine sorting steps, the present application can more effectively recover valuable metals such as lead, zinc, silver, iron and manganese, especially the recovery rate of silver is significantly improved. By optimizing the sorting process, the waste of resources is reduced, so that the valuable metals in the ore are more fully utilized. By optimizing the use of flotation reagents and the sorting process, the reagent consumption and operation complexity are reduced, thereby reducing production costs. Due to the improved recovery rate of valuable metals, especially the recovery of silver, the present method can significantly improve the overall economic benefits of the mineral processing process.

[0038] By crushing the raw ore and wet grinding it to a specific fineness, ideal particle size conditions are created for subsequent flotation and magnetic separation, which is conducive to improving the sorting efficiency. The silver-lead-zinc mixed roughing and concentrating steps can effectively enrich the lead, zinc and silver minerals into the concentrate, while the mixed scavenging further ensures the recovery of valuable metals. Iron and manganese minerals can be effectively separated by weak magnetic roughing and concentrating, as well as strong magnetic roughing and concentrating. Regrinding the roughing concentrate can further refine the mineral particle size and improve the sorting effect in the concentrating stage, thereby improving the concentrate quality and metal recovery rate. Through step-by-step fine control and process design, the present application can better process lead-zinc-silver ores with associated iron and manganese, solving the problems of low silver recovery rate, complex operation and high cost in traditional processes.

[0039] Furthermore, in some embodiments, in step S1, the slurry concentration is 30-40%.

[0040] In the technical solution of the embodiment of the present application, controlling the slurry concentration at 30-40% is helpful to achieve efficient sorting of lead-zinc-silver ore. By accurately controlling the slurry concentration, the entire sorting process can be optimized while ensuring the sorting effect, thereby improving production efficiency and economic benefits.

[0041] Furthermore, in some embodiments, in step S2, the reagents for mixed roughing are 40-60 g / t of copper sulfate, 50-70 g / t of butyl xanthate, 15-25 g / t of butyl ammonium black powder, and 20-40 g / t of 2# oil. The reagents for the first mixed scavenging are 20-40 g / t of butyl xanthate and 5-15 g / t of butyl ammonium black powder; the reagents for the second mixed scavenging are 10-20 g / t of butyl xanthate and 3-8 g / t of butyl ammonium black powder. The mixed selected middlings are returned to the previous operation step by step, and no flotation reagents are added to the selected operation; the mixed scavenging concentrates are returned to the previous operation step by step.

[0042] In the technical solution of the embodiment of the present application, copper sulfate is used as an activator to activate sphalerite and pyrite, improve their interaction with the flotation agent, and thus promote their flotation. As a collector, butyl xanthate has a good collecting effect on lead and silver minerals, which helps these minerals float in flotation. Butyl ammonium black medicine is used in combination with butyl xanthate to improve the collection effect on certain difficult-to-select minerals. 2# oil is used as a frother to help form stable and appropriate bubbles, which are the carriers for mineral particles to float to the surface of the slurry. The amount of reagents used in the first mixed scavenging and second mixed scavenging is further reduced to optimize the efficiency and cost of the reagents.

[0043] During the mixed concentration process, no flotation reagents are added. This is because in the concentration stage, the main purpose is to further purify the already enriched minerals, and no additional reagents are needed to promote the flotation of the minerals. The mixed selected middlings are returned to the previous operation step by step, which helps to improve the metal recovery rate of the entire flotation process. Returning the scavenged concentrate to the previous operation, that is, returning to the roughing or the previous round of concentration, can allow this part of the minerals that have been enriched with valuable metals to re-enter the sorting process. Doing so can increase the chances of valuable metals being recovered, thereby improving the overall metal recovery rate. By returning the concentrate, it can ensure that the valuable components in the ore are maximized and reduce the waste of resources.

[0044] Through reagent configuration and process control, the embodiments of the present application can effectively separate valuable metals from lead-zinc-silver ores with associated iron and manganese, while optimizing the use of reagents, reducing costs, and improving sorting efficiency.

[0045] Furthermore, in some embodiments, in step S3, the magnetic field strength of the weak magnetic roughing and weak magnetic concentrating is 900-1100 GS. The regrinding process is to regrind the weak magnetic roughing concentrate to a particle mass content of 88-92% at a particle size of -0.025 mm.

[0046] In the technical solution of the embodiment of the present application, by controlling the magnetic field strength, minerals with weak magnetism can be effectively separated from the ore pulp. The magnetic field strength range can not only ensure sufficient sorting efficiency, but also avoid increased energy consumption and equipment wear caused by excessive magnetic field strength. The regrinding process helps to improve the dissociation degree of magnetic minerals, making mineral particles easier to be separated and recovered during weak magnetic concentration. Through regrinding, the grade of iron ore concentrate can be further improved, the impurity content can be reduced, and the quality of the final product can be improved.

[0047] Further, in some embodiments, in step S4, the magnetic field strength of the strong magnetic roughing is 9000-12000 GS. The regrinding process is to regrind the strong magnetic roughing concentrate to a particle mass content of 93-96% at a particle size of -0.025 mm. The magnetic field strength of the first strong magnetic concentration is 7000-9000 GS, the magnetic field strength of the second strong magnetic concentration is 5000-7000 GS, and the magnetic field strength of the third strong magnetic concentration is 4000-6000 GS.

[0048] In the technical solution of the embodiment of the present application, a higher magnetic field strength helps to improve the recovery rate in the roughing stage and reduce the loss of magnetic minerals. The purpose of the regrinding process is to increase the surface area of ​​the mineral particles by fine grinding, so that the magnetic minerals are more easily captured under a lower magnetic field strength. The first strong magnetic concentration is the first concentration carried out after the roughing, and the purpose is to further remove non-magnetic impurities from the mineral. The magnetic field intensity of the second strong magnetic concentration is lower than that of the first, which helps to separate minerals with weaker magnetism from already relatively pure minerals. The third strong magnetic concentration is used to further improve the grade of the concentrate, and the reduction in the magnetic field intensity helps to separate the minerals with the weakest magnetism. Through these step designs, the embodiment of the present application can achieve efficient separation of manganese minerals from lead-zinc-silver ores with associated iron and manganese, and gradually improve the purity of the concentrate by gradually reducing the magnetic field intensity.

[0049] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0050] Example

[0051] like Figure 1 As shown, this embodiment provides a method for the combined separation of lead-zinc-silver ores with associated iron and manganese. In terms of mass percentage, the silver content in this embodiment is 430.52 g / t, and the contents of lead, zinc, iron, manganese and sulfur are 0.69%, 0.34%, 21.48%, 7.05% and 3.38% respectively; the specific steps are as follows:

[0052] S1. Crushing the raw ore to -2mm, then wet grinding the crushed ore, the grinding fineness is -0.074mm accounting for 85-89%, adding water to the pulp concentration of 30-40%;

[0053] S2. Add reagents to carry out silver, lead and zinc mixed flotation roughing, scavenging and concentrating to obtain sulfide mixed concentrate and tailings. The roughing reagents are 50g / t copper sulfate, 60g / t butyl xanthate, 20g / t butyl ammonium black, and 30g / t 2# oil; the scavenging I reagents are 30g / t butyl xanthate and 10g / t butyl ammonium black; the scavenging II reagents are 15g / t butyl xanthate and 5g / t butyl ammonium black. The scavenging I and scavenging II concentrates are returned to the previous operation in turn; no flotation reagents are added in the concentrating operation. The middlings of concentrating I to IV are returned to the previous operation in turn.

[0054] S3. The silver, lead and zinc mixed flotation tailings are subjected to weak magnetic roughing with a magnetic field strength of 1000GS. The weak magnetic rough concentrate is re-ground to -0.025mm, accounting for 90%. The re-ground weak magnetic rough concentrate is subjected to two magnetic separations with magnetic field strengths of 1000GS and 1000GS respectively. The middlings from the two concentrations are combined with the magnetic concentrate after concentration III of 1000GS to obtain iron concentrate. The tailings from concentration III and the weak magnetic roughing tailings enter the strong magnetic operation to recover manganese.

[0055] S4. The iron tailings are subjected to strong magnetic roughing with a magnetic field strength of 10000GS. The strong magnetic rough concentrate is re-ground to -0.025mm, accounting for 95%. The re-ground strong magnetic rough concentrate is subjected to two strong magnetic separations with magnetic field strengths of 8000GS and 6000GS respectively. The two concentrated middlings are combined with the strong magnetic concentrate after 5000GS concentration III to obtain manganese concentrate. The concentrated III tailings are combined with the strong magnetic roughing tailings to form tailings.

[0056] The closed-circuit test in this embodiment can obtain the following mineral processing indicators: the silver grade of the silver-lead mixed concentrate reaches 3137.16g / t, the lead grade is 5.61%, the zinc grade is 2.32%, the silver recovery rate is 85.45%, the lead recovery rate is 94.61%, and the zinc recovery rate is 79.55%. At the same time, the iron grade in the iron concentrate is 60.07%, the iron recovery rate is 8.11%, and the magnetic iron recovery rate is 79.05%. The manganese grade in the manganese concentrate is 15.30%, and the manganese recovery rate is 76.38%. The tailings yield of the whole process is 50.23%, and the silver grade is 37.15g / t.

[0057] The present application can more effectively recover valuable metals such as silver, lead, and zinc by first performing mixed roughing and fine separation of silver, lead, and zinc, because the flotation process is usually better than magnetic separation for the separation effect of these metals. After the mixed concentrate is obtained by flotation, the tailings are magnetically separated to separate iron and manganese, which can avoid the contamination of the flotation concentrate during the magnetic separation process and improve the purity of the final product. Since magnetic separation usually has low consumption, flotation can reduce the processing volume of subsequent magnetic separation, thereby reducing the overall beneficiation cost. This method can separate valuable metals faster by first flotation and then magnetic separation, reducing processing time and improving beneficiation efficiency. The reagents used in the flotation process are optimized for silver, lead, and zinc, while magnetic separation does not require reagents, reducing the overall dosage of reagents and reducing environmental pollution. This method can adapt to ores with complex compositions, remove some metals by first flotation, and then separate iron and manganese by magnetic separation, so as to better handle lead-zinc-silver ores with associated iron and manganese, and achieve efficient recovery of silver, iron, and manganese.

[0058] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A combined separation method of lead-zinc-silver ores with associated iron and manganese, characterized in that: The following steps are involved: S1. Crushing the raw ore to -2mm, then wet grinding, grinding the ore to a particle size of -0.074mm with a mass content of 85-89%, adding water to adjust the slurry concentration to a predetermined range; S2. The slurry obtained in step S1 is subjected to mixed roughing of silver, lead and zinc to obtain a mixed roughing concentrate and a mixed roughing tailings; the mixed roughing concentrate is subjected to four mixed selections to obtain a mixed concentrate; the mixed roughing tailings are subjected to two mixed scavengings to obtain a mixed tailings; S3. The mixed tailings obtained in step S2 are subjected to weak magnetic roughing to obtain weak magnetic roughing concentrate and weak magnetic roughing tailings; the weak magnetic roughing concentrate is subjected to a regrinding process, and then subjected to two weak magnetic concentrations to obtain a weak magnetic concentration concentrate; the middlings obtained from the two weak magnetic concentrations are subjected to a third weak magnetic concentration, and the concentrate obtained is combined with the weak magnetic concentration concentrate to obtain an iron concentrate, and the third weak magnetic concentration tailings are combined with the weak magnetic roughing tailings to obtain an iron concentration tailings; S4. The iron tailings obtained in step S3 are subjected to strong magnetic roughing to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings; the strong magnetic roughing concentrate is subjected to a regrinding process, and then subjected to two strong magnetic concentrations to obtain a strong magnetic concentration concentrate; the middlings obtained from the two strong magnetic concentrations are subjected to a third strong magnetic concentration, and the concentrate obtained is combined with the strong magnetic concentration concentrate to obtain a manganese concentrate, and the tailings from the third strong magnetic concentration are combined with the strong magnetic roughing tailings to obtain tailings.

2. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 1, characterized in that: In step S1, the slurry concentration is 30-40%.

3. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 1, characterized in that: In step S2, the mixed roughing reagents are 40-60 g / t of copper sulfate, 50-70 g / t of butyl xanthate, 15-25 g / t of butyl ammonium black powder, and 20-40 g / t of 2# oil.

4. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 3, characterized in that: The reagents for the first mixed sweep are 20-40 g / t of butyl xanthate and 5-15 g / t of butyl ammonium black powder; the reagents for the second mixed sweep are 10-20 g / t of butyl xanthate and 3-8 g / t of butyl ammonium black powder.

5. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 3, characterized in that: The mixed selected middlings are returned to the previous operation in sequence and level by level; the mixed scavenged concentrates are returned to the previous operation in sequence.

6. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 1, characterized in that: In step S3, the magnetic field strength of the weak magnetic roughing and the weak magnetic concentrating is 900-1100 GS.

7. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 6, characterized in that: In step S3, the regrinding process is to regrind the weak magnetic rougher concentrate to a particle mass content of 88-92% at a particle size of -0.025 mm.

8. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 1, characterized in that: In step S4, the magnetic field strength of the strong magnetic roughing is 9000-12000 GS.

9. The combined separation method of lead-zinc-silver ore with associated iron and manganese according to claim 8, characterized in that: In step S4, the regrinding process is to regrind the high-intensity magnetic rougher concentrate to a particle mass content of 93-96% at a particle size of -0.025 mm.

10. The combined separation method of lead, zinc and silver ores with associated iron and manganese according to claim 9, characterized in that: The magnetic field strength of the first strong magnetic selection is 7000-9000GS, the magnetic field strength of the second strong magnetic selection is 5000-7000GS, and the magnetic field strength of the third strong magnetic selection is 4000-6000GS.

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