A method for comprehensive recovery of valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources

Abstract

The present invention provides a method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources, and belongs to the field of resource recovery technology. The present invention first grinds and magnetically separates complex iron resources to recover the iron resources therein, and then granulates the magnetic tailings with a reducing agent and a binder and then roasts them, which is beneficial to the heat and mass transfer of the pellets, promotes the volatilization of each component, and improves the recovery rate of each component. The roasting residue is subjected to flotation and magnetic separation to recover the copper therein, thereby achieving the comprehensive recovery of iron, lead, zinc, tin, indium and copper in complex iron resources, and improving the recovery rate of each component. At the same time, the magnetic separation tailings can be used as building materials to achieve 100% utilization of resources. The results of the embodiment show that after recovery by the method of the present invention, the recovery rates of tin, indium, lead, zinc and copper can reach 95%, 95%, 98%, 90% and 72% respectively, and the comprehensive recovery rate of iron reaches 80%, with a grade of 63%.

Description

Technical Field

[0001] The invention relates to the technical field of resource recovery, and in particular to a method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources. Background Art

[0002] As we all know, iron ore, as an important raw material for the steel industry, is a strategic mineral resource in my country. In 2019, my country's iron ore demand reached 1.28 billion tons, of which 1.069 billion tons were imported, and the external dependence rate reached more than 80%. Since 2020, the external dependence rate of iron ore has remained high. China's iron ore sources are mainly Brazil and Australia, which seriously restricts the development of my country's steel industry. Although my country's iron resources are abundant, they are mainly polymetallic complex ores and difficult-to-select low-grade ores, which are difficult to use in the existing beneficiation process. Therefore, the economical and efficient use of iron resources in polymetallic complex ores is undoubtedly of great significance to buffering iron ore resources and price pressures.

[0003] Tin-lead-zinc-copper complex magnetite is a typical complex iron resource with huge reserves. It has been found in many provinces including Yunnan, Inner Mongolia, Hunan and Guangxi. A large number of scholars have studied complex iron resources containing tin, lead, zinc and copper. At present, the research mainly focuses on the separation of tin, lead, zinc and iron phases, without considering the recovery of copper, and the recovery rate of each component is also low.

[0004] Therefore, there is an urgent need for a method that can comprehensively recover the valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources with a high recovery rate of each component. Summary of the invention

[0005] The object of the present invention is to provide a method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources. The method provided by the present invention can realize the comprehensive recovery of iron, lead, zinc, tin, indium and copper, and the recovery rate is relatively high.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources, comprising the following steps:

[0008] (1) subjecting complex iron resources to first grinding, first magnetic separation, second grinding and second magnetic separation in sequence to obtain magnetic concentrate and magnetic tailings;

[0009] (2) mixing the magnetically separated tailings obtained in step (1) with a reducing agent and a binder and granulating the mixture to obtain tailings pellets;

[0010] (3) roasting the tailings pellets obtained in step (2) in an inert gas to obtain flue gas containing tin, indium, lead and zinc and roasting residues;

[0011] (4) The roasting residue obtained in step (3) is subjected to flotation and magnetic separation in sequence to obtain copper concentrate, reduced iron powder and tailings.

[0012] Preferably, the magnetic field strength of the first magnetic separation and the second magnetic separation in step (1) are independently 50-100 KA / m.

[0013] Preferably, the reducing agent in step (2) comprises waste cathode carbon, waste activated carbon or waste anode carbon.

[0014] Preferably, the binder in step (2) comprises an inorganic binder, an organic binder or an organic-inorganic composite binder.

[0015] Preferably, in step (2), the mass ratio of the magnetic separation tailings, the reducing agent and the binder is 1:(0.02-0.1):(0.02-0.05).

[0016] Preferably, the diameter of the tailings pellets in step (2) is 8 to 12 mm.

[0017] Preferably, the calcination temperature in step (3) is 1000-1200° C., and the calcination time is 20-150 min.

[0018] Preferably, the heating rate of heating to the calcination temperature in step (3) is 5 to 20° C. / min.

[0019] Preferably, the flotation reagent used in the flotation in step (4) includes xanthate, black powder, thiourea or mercaptan.

[0020] Preferably, the magnetic field intensity during magnetic separation in step (4) is 80 to 120 KA / m.

[0021] The present invention provides a method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources, comprising the following steps: (1) subjecting the complex iron resources to first grinding, first magnetic separation, second grinding and second magnetic separation in sequence to obtain magnetic concentrate and magnetic tailings; (2) mixing the magnetic tailings obtained in step (1) with a reducing agent and a binder and then granulating them to obtain tailings pellets; (3) roasting the tailings pellets obtained in step (2) in an inert gas to obtain flue gas containing tin, indium, lead and zinc and roasting residues; (4) sequentially subjecting the roasting residues obtained in step (3) to flotation and magnetic separation to obtain copper concentrate, reduced iron powder and tailings. The present invention firstly grinds the complex iron resources twice and magnetically separates them twice to recover the iron resources therein, then granulates the magnetically separated tailings with a reducing agent and a binder and then roasts them, which is beneficial to the heat and mass transfer of the pellets, promotes the volatilization of each component, and improves the recovery rate of each component. The roasting residue is subjected to flotation and magnetic separation to recover the copper therein, thereby realizing the comprehensive recovery of iron, lead, zinc, tin, indium and copper in the complex iron resources, and improving the recovery rate of each component. At the same time, the magnetically separated tailings can be used as building materials to achieve 100% utilization of resources. The results of the embodiment show that after recovery by the method of the present invention, the recovery rates of tin, indium, lead, zinc and copper can reach 95%, 95%, 98%, 90% and 72% respectively, and the comprehensive recovery rate of iron reaches 80%, with a grade of 63%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a process flow chart of the method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources. DETAILED DESCRIPTION

[0023] The present invention provides a method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources, comprising the following steps:

[0024] (1) subjecting complex iron resources to first grinding, first magnetic separation, second grinding and second magnetic separation in sequence to obtain magnetic concentrate and magnetic tailings;

[0025] (2) mixing the magnetically separated tailings obtained in step (1) with a reducing agent and a binder and granulating the mixture to obtain tailings pellets;

[0026] (3) roasting the tailings pellets obtained in step (2) in an inert gas to obtain flue gas containing tin, indium, lead and zinc and roasting residues;

[0027] (4) The roasting residue obtained in step (3) is subjected to flotation and magnetic separation in sequence to obtain copper concentrate, reduced iron powder and tailings.

[0028] The present invention sequentially performs one-pass grinding, one-pass magnetic separation, two-pass grinding and two-pass magnetic separation on complex iron resources to obtain magnetic separation concentrate and magnetic separation tailings.

[0029] The present invention has no special limitation on the source of the complex iron resources, and the complex iron resources known to those skilled in the art can be used. In the present invention, the complex iron resources are preferably from tin iron ore, high iron tin medium ore or multi-metal associated iron ore.

[0030] In the present invention, the elements in the complex iron resources include Fe, Sn, In, Cu, Zn, Pb, S and other conventional elements.

[0031] In the present invention, the complex iron resource is preferably dried before use.

[0032] The present invention has no special limitation on the drying operation, and any drying technical solution well known to those skilled in the art may be used.

[0033] In the present invention, the mineral particle size ratio of -74 μm after the first grinding is preferably 50-100%, more preferably 60-90%, and most preferably 70-80%. The present invention limits the particle size of the mineral after the first grinding to the above range, which can facilitate the magnetic separation.

[0034] The present invention has no special limitation on the time of the first grinding, as long as the particle size of the mineral after grinding is within the above range.

[0035] In the present invention, the magnetic field strength of the first magnetic separation is preferably 50-100KA / m, more preferably 60-90KA / m, and most preferably 70-80KA / m. The present invention limits the magnetic field strength of the first magnetic separation to the above range, and can more fully separate the iron in complex iron resources. The present invention has no special limitation on the time of the first magnetic separation, and the magnetic separation concentrate can be fully separated.

[0036] In the present invention, after the first magnetic separation, a magnetic separation concentrate and a magnetic separation tailings are obtained.

[0037] After obtaining the first magnetic separation concentrate, the present invention performs second grinding and second magnetic separation on the first magnetic separation concentrate.

[0038] In the present invention, the mineral particle size ratio of -38 μm after the second grinding is preferably 60-100%, more preferably 70-90%, and most preferably 80%. The present invention limits the particle size of the mineral after the second grinding to the above range, which is conducive to magnetic separation.

[0039] The present invention has no special limitation on the time of the secondary grinding, as long as the particle size of the mineral after grinding is within the above range.

[0040] In the present invention, the magnetic field strength of the second magnetic separation is preferably 50-100KA / m, more preferably 60-90KA / m, and most preferably 70-80KA / m. The present invention limits the magnetic field strength of the second magnetic separation to the above range, and can more fully separate the iron in complex iron resources. The present invention has no special limitation on the time of the second magnetic separation, and the magnetic separation concentrate can be fully separated.

[0041] In the present invention, magnetic separation concentrate and second magnetic separation tailings are obtained after the second magnetic separation.

[0042] In the present invention, the magnetically separated concentrate can be used to prepare high-quality iron.

[0043] In the present invention, the second magnetic separation tailings obtained by the second magnetic separation and the first magnetic separation tailings obtained by the first magnetic separation are combined to obtain the magnetic separation tailings.

[0044] After obtaining the magnetic separation tailings, the present invention mixes the magnetic separation tailings with a reducing agent and a binder and then granulates them to obtain tailings pellets.

[0045] In the present invention, the reducing agent preferably includes waste cathode carbon, waste activated carbon or waste anode carbon. The present invention uses carbon-containing secondary solid waste instead of traditional anthracite as the reducing agent, which greatly reduces the roasting cost.

[0046] In the present invention, the binder preferably includes an inorganic binder, an organic binder or an organic-inorganic composite binder, and more preferably includes bentonite, slaked lime, peridot or modified starch.

[0047] In the present invention, the mass ratio of the magnetic tailings, the reducing agent and the binder is preferably 1:(0.02-0.1):(0.02-0.05), and more preferably 1:(0.05-0.08):(0.03-0.04). The present invention limits the mass ratio of the magnetic tailings, the reducing agent and the binder to the above range, which can make the metal oxides in the magnetic tailings more fully reduced to metals, promote their volatilization, and improve their recovery rate, and the pellets have a more suitable pore structure, further improving their volatility and recovery rate.

[0048] In the present invention, the diameter of the tailings pellets is preferably 8 to 12 mm, more preferably 9 to 10 mm. The present invention limits the diameter of the tailings pellets to the above range, which can make them have a higher specific surface area, facilitate mass transfer and heat transfer, promote metal volatilization, and improve metal recovery rate.

[0049] The present invention has no special limitation on the granulation operation, and a granulation technical solution well known to those skilled in the art may be adopted to ensure that the diameter of the pellets is within the above range.

[0050] After obtaining the tailings pellets, the invention roasts the tailings pellets in an inert gas to obtain flue gas containing tin, indium, lead and zinc and roasting residues.

[0051] In the present invention, the inert gas is preferably nitrogen.

[0052] In the present invention, the inert gas flow rate is preferably 0.05-0.5 L / min, more preferably 0.1-0.4 L / min, and most preferably 0.2-0.3 L / min. The present invention limits the inert gas flow rate to the above range, which can effectively take away the volatile gas products and avoid the metal in the pellets from reacting with oxygen.

[0053] In the present invention, the calcination temperature is preferably 1000-1200°C, more preferably 1050-1150°C, and most preferably 1100°C; the calcination time is preferably 20-150min, more preferably 50-120min, and most preferably 80-100min; the heating rate to the calcination temperature is preferably 5-20°C / min, and more preferably 10-15°C / min. The present invention limits the calcination temperature, time, and heating rate within the above range, so that tin, indium, lead, and sulfur can fully react to form sulfides, further improving the recovery rate of metals.

[0054] In the present invention, during the roasting process, carbonates in the tailings pellets are decomposed, metal oxides are reduced to metals by a reducing agent, and then react with sulfur in the tailings pellets to form metal sulfide flue gas.

[0055] After obtaining the flue gas containing tin, indium, lead and zinc, the present invention preferably sequentially cools, dusts, removes dust and washes the flue gas containing tin, indium, lead and zinc to obtain components containing tin, indium, lead and zinc.

[0056] The present invention has no special limitation on the cooling, dust collecting, dedusting and washing operations, and the cooling, dust collecting, dedusting and washing technical solutions well known to those skilled in the art may be adopted.

[0057] After obtaining the roasting residue, the present invention sequentially performs flotation and magnetic separation on the roasting residue to obtain copper concentrate, reduced iron powder and tailings.

[0058] In the present invention, the roasting residue is preferably cooled and crushed in sequence before flotation.

[0059] The present invention has no special limitation on the cooling operation, and any cooling technical solution well known to those skilled in the art may be used.

[0060] In the present invention, the mineral particle size ratio of -74 μm after crushing is preferably 100%. The present invention limits the mineral particle size after crushing to the above range, which can be beneficial to flotation and magnetic separation.

[0061] In the present invention, the flotation reagent during the flotation preferably includes xanthate, black medicine, thiourea or mercaptan; the addition amount of the flotation reagent is preferably 50-100 g / t, more preferably 60-90 g / t, and most preferably 70-80 g / t. The present invention limits the addition amount of the flotation reagent to the above range, and can fully recover the copper in the roasting residue. In the present invention, copper concentrate and flotation tailings are obtained after the flotation, and then the flotation tailings are subjected to magnetic separation.

[0062] In the present invention, the magnetic field strength during magnetic separation is preferably 80-120 KA / m, more preferably 90-110 KA / m, and most preferably 100 KA / m. The present invention limits the magnetic field strength during magnetic separation to the above range, and can more fully recover the iron in the flotation tailings.

[0063] In the present invention, the tailings can be used as building materials.

[0064] The flowchart of the method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper in complex iron resources of the present invention is preferably as follows Figure 1 As shown: first, the complex iron ore containing tin, indium, zinc, lead and copper is crushed and then subjected to a magnetic separation (magnetic roughing) to obtain magnetic concentrate and magnetic tailings. The magnetic concentrate is then subjected to magnetic concentration (second magnetic separation) to obtain magnetic concentrate and magnetic tailings. The two magnetic tailings are combined and pelletized with a binder and a reducing agent. They are coupled roasted in an inert gas, and the flue gas is discharged after dust collection. The roasting residue is crushed and then floated to obtain copper concentrate and flotation tailings. The flotation tailings are magnetically separated to obtain magnetic tailings (i.e. tailings) and reduced iron powder. The magnetic tailings can be used as building materials.

[0065] The present invention firstly grinds and magnetically separates the complex iron resources to recover the iron resources therein, and then granulates the magnetic separation tailings with a reducing agent and a binder and then roasts them, which is beneficial to the heat and mass transfer of the pellets, promotes the volatilization of each component, and improves the recovery rate of each component. The roasting residue is subjected to flotation and magnetic separation to recover the copper therein, thereby realizing the comprehensive recovery of iron, lead, zinc, tin, indium and copper in the complex iron resources, controlling the process parameters such as the dosage and reaction temperature in the steps, and improving the recovery rate of each component. At the same time, the magnetic separation tailings can be used as building materials, realizing 100% utilization of resources.

[0066] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] Example 1

[0068] (1) A complex iron resource containing lead, zinc, tin and copper (Fe 31.31wt.%, Sn 0.28wt.%, In 0.008wt.%, Cu 0.17wt.%, Zn 0.40wt.%, Pb 0.30wt.%, S 0.34wt.%) is subjected to a first grinding process, wherein the proportion of -74μm mineral particle size is 75%, and then subjected to a first magnetic separation process, wherein the magnetic field strength is 75KA / m, and then subjected to a second grinding process, wherein the proportion of -38μm mineral particle size is 85%, and then subjected to a second magnetic separation process, wherein the magnetic field strength is 75KA / m, to obtain a magnetic concentrate and a magnetic tailings;

[0069] (2) mixing the magnetic separation tailings with spent cathode carbon and bentonite in a mass ratio of 1:0.05:0.02 to obtain tailings pellets with a diameter of 8 to 12 mm;

[0070] (3) heating the pellets obtained in step (2) from room temperature to 1100° C. at a heating rate of 10° C. / min under a nitrogen flow rate of 0.5 L / min, and keeping the temperature for 60 min. The high-temperature flue gas generated during the roasting is dusted to recover the volatilized tin, indium, lead, and zinc resources. The flue gas is washed to meet the emission requirements and then discharged into the atmosphere;

[0071] (4) After the roasting residue is cooled and crushed, the proportion of -74μm mineral particle size is 100%, and copper is recovered by flotation. The amount of flotation agent xanthate added is 80g / t. The reduced iron powder is recovered by weak magnetic separation process, and the magnetic field strength is 100KA / m.

[0072] After testing and calculation, the recovery rates of tin, indium, lead, zinc and copper reached 95%, 95%, 98%, 90% and 72% respectively. The comprehensive recovery rate of iron was 80% and the grade was 63%. The tailings can be used as building materials, achieving 100% utilization of resources.

[0073] Example 2

[0074] (1) A complex iron resource containing lead, zinc, tin and copper (Fe 35.26wt.%, Sn 0.22wt.%, In 0.007wt.%, Cu 0.21wt.%, Zn 0.37wt.%, Pb 0.25wt.%, S 0.46wt.%) is subjected to a first grinding process, wherein the proportion of -74μm mineral particle size is 80%, and then subjected to a first magnetic separation process, wherein the magnetic field strength is 100KA / m, and then subjected to a second grinding process, wherein the proportion of -38μm mineral particle size is 85%, and then subjected to a second magnetic separation process, wherein the magnetic field strength is 100KA / m, to obtain a magnetic concentrate and a magnetic tailings;

[0075] (2) mixing the magnetic separation tailings with spent cathode carbon and bentonite in a mass ratio of 1:0.04:0.02 to obtain tailings pellets with a diameter of 8 to 12 mm;

[0076] (3) heating the pellets obtained in step (2) from room temperature to 1080° C. at a heating rate of 15° C. / min under a nitrogen flow rate of 0.5 L / min, and keeping the temperature for 80 min. The high-temperature flue gas generated during the roasting is dusted and the volatilized tin, indium, lead and zinc resources are recovered. The flue gas is washed to meet the emission requirements and then discharged into the atmosphere.

[0077] (4) After the roasting residue is cooled and crushed, the proportion of -74μm mineral particle size is 100%. Flotation is used to recover copper, and the amount of flotation agent xanthate added is 90g / t. A weak magnetic separation process is used to recover the reduced iron powder, and the magnetic field strength is 100KA / m.

[0078] After testing and calculation, the recovery rates of tin, indium, lead, zinc and copper reached 94%, 93%, 97%, 88% and 74% respectively. The comprehensive recovery rate of iron was 83% and the grade was 61%. The tailings can be used as building materials, achieving 100% utilization of resources.

[0079] Example 3

[0080] (1) A complex iron resource containing lead, zinc, tin and copper (Fe 33.21wt.%, Sn 0.14wt.%, In 0.008wt.%, Cu 0.27wt.%, Zn 0.21wt.%, Pb 0.37wt.%, S 0.38wt.%) is subjected to a first grinding process, wherein the proportion of -74μm mineral particle size is 70%, and then subjected to a first magnetic separation process, wherein the magnetic field strength is 80KA / m, and then subjected to a second grinding process, wherein the proportion of -38μm mineral particle size is 80%, and then subjected to a second magnetic separation process, wherein the magnetic field strength is 80KA / m, to obtain a magnetic concentrate and a magnetic tailings;

[0081] (2) mixing the magnetic separation tailings with spent cathode carbon and bentonite in a mass ratio of 1:0.03:0.02 to obtain tailings pellets with a diameter of 8 to 12 mm;

[0082] (3) heating the pellets obtained in step (2) from room temperature to 1100° C. at a heating rate of 15° C. / min under a nitrogen flow rate of 0.5 L / min, and keeping the temperature for 60 min. The high-temperature flue gas generated during the roasting is dusted to recover the volatilized tin, indium, lead, and zinc resources. The flue gas is washed to meet the emission requirements and then discharged into the atmosphere;

[0083] (4) After the roasting residue is cooled and crushed, the proportion of -74μm mineral particle size is 100%, and copper is recovered by flotation. The amount of xanthate added is 50g / t. The reduced iron powder is recovered by weak magnetic separation process. The magnetic field strength is 100KA / m.

[0084] After testing and calculation, the recovery rates of tin, indium, lead, zinc and copper reached 92%, 93%, 98%, 91% and 70% respectively. The comprehensive recovery rate of iron was 76% and the grade was 64%. The tailings can be used as building materials, achieving 100% utilization of resources.

[0085] Example 4

[0086] (1) A complex iron resource containing lead, zinc, tin and copper (Fe 30.21wt.%, Sn 0.18wt.%, In 0.009wt.%, Cu 0.33wt.%, Zn 0.12wt.%, Pb 0.44wt.%, S 0.51wt.%) is subjected to a first grinding process, wherein the proportion of -74μm mineral particle size is 80%, and then subjected to a first magnetic separation process, wherein the magnetic field strength is 85KA / m, and then subjected to a second grinding process, wherein the proportion of -38μm mineral particle size is 80%, and then subjected to a second magnetic separation process, wherein the magnetic field strength is 85KA / m, to obtain a magnetic concentrate and a magnetic tailings;

[0087] (2) mixing the magnetic separation tailings with spent cathode carbon and bentonite in a mass ratio of 1:0.04:0.02 to obtain tailings pellets with a diameter of 8 to 12 mm;

[0088] (3) heating the pellets obtained in step (2) from room temperature to 1050° C. at a heating rate of 10° C. / min under a nitrogen flow rate of 0.5 L / min, and keeping the temperature for 50 min. The high-temperature flue gas generated during the roasting is dusted to recover the volatilized tin, indium, lead, and zinc resources. The flue gas is washed to meet the emission requirements and then discharged into the atmosphere.

[0089] (4) After the roasting residue is cooled and crushed, the proportion of -74μm mineral particle size is 100%, and copper is recovered by flotation. The amount of xanthate added is 50g / t. The reduced iron powder is recovered by weak magnetic separation process. The magnetic field strength is 100KA / m.

[0090] After testing and calculation, the recovery rates of tin, indium, lead, zinc and copper reached 91%, 95%, 95%, 87% and 71% respectively. The comprehensive recovery rate of iron was 72% and the grade was 62%. The tailings can be used as building materials, achieving 100% utilization of resources.

[0091] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for comprehensively recovering valuable components of iron, tin, indium, lead, zinc and copper from complex iron resources, comprising the following steps: (1) subjecting complex iron resources to first grinding, first magnetic separation, second grinding and second magnetic separation in sequence to obtain magnetic concentrate and magnetic tailings; the complex iron resources are from tin-iron ore, high-iron tin medium ore or multi-metal associated iron ore; the elements in the complex iron resources include Fe, Sn, In, Cu, Zn, Pb, S and other conventional elements; (2) mixing the magnetic tailings obtained in step (1) with a reducing agent and a binder and granulating the mixture to obtain tailings pellets; the mass ratio of the magnetic tailings, the reducing agent and the binder in step (2) is 1:(0.02-0.05):(0.02-0.05); (3) roasting the tailings pellets obtained in step (2) in an inert gas to obtain flue gas containing tin, indium, lead and zinc and roasting residues; the roasting temperature in step (3) is 1000 to 1100° C. and the roasting time is 20 to 150 min; (4) The roasting residue obtained in step (3) is subjected to flotation and magnetic separation in sequence to obtain copper concentrate, reduced iron powder and tailings.

2. The method according to claim 1, characterized in that In the step (1), the magnetic field strengths of the first magnetic separation and the second magnetic separation are independently 50 to 100 KA / m.

3. The method according to claim 1, characterized in that The reducing agent in step (2) includes waste cathode carbon, waste activated carbon or waste anode carbon.

4. The method according to claim 1, characterized in that The binder in step (2) includes an inorganic binder, an organic binder or an organic-inorganic composite binder.

5. The method according to claim 1, characterized in that: The diameter of the tailings pellets in step (2) is 8 to 12 mm.

6. The method according to claim 1, characterized in that The heating rate of the step (3) to the calcination temperature is 5 to 20°C / min.

7. The method according to claim 1, characterized in that The flotation reagents used in the flotation in step (4) include xanthate, black powder, thiourea or mercaptan.

8. The method according to claim 1, characterized in that The magnetic field intensity during magnetic separation in step (4) is 80-120 KA / m.

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