A method for cascade recovery of iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore.

Abstract

This invention provides a method for the cascade recovery of iron, copper, and cobalt from copper-cobalt skarn-type iron ore. The method includes: crushing and dry screening of the ore; dry magnetic separation of the oversize material to recover coarse iron concentrate; wet ball milling of the undersize material for flotation to obtain a copper-cobalt mixed concentrate; and magnetic separation of the tailings from the flotation to obtain a fine iron concentrate. The copper-cobalt mixed concentrate is dried, granulated, and then combined with the tailings from the dry magnetic separation for bio-heap leaching to recover copper and cobalt. This invention addresses the high iron content in copper-cobalt skarn-type iron ore by first crushing and dry screening to achieve early recovery of coarse iron concentrate through coarse and fine separation. Subsequently, a cascade recovery approach using magnetic separation-flotation-bio-heap leaching is employed to recover both copper, cobalt, and fine iron concentrate. This eliminates the complex steps of re-grinding and multi-stage cleaning in traditional processes, offering advantages such as a short process flow, simple operation, and low consumption of flotation reagents.

Description

Technical Field

[0001] This invention relates to the field of beneficiation and metallurgy, and in particular to a method for the cascade recovery of iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore. Background Technology

[0002] Copper-cobalt skarn-type iron deposits are typical contact metasomatic deposits formed at the contact zone between magmatic activity and carbonate host rocks. These deposits are formed in post-collisional extensional environments or subduction zone-related tectonic environments, resulting in the iron-bearing mineral magnetite being mainly medium to fine-grained, in subhedral to anhedral granular form, with some disseminated distributions. The main copper-bearing minerals have an average grain size of 0.15 mm, mostly in irregular granular, disseminated, and banded distributions, with some in fine-grained distributions. Cobalt is mainly cobalt pyrite, with a finer grain size than copper minerals, averaging about 0.076 mm, and is closely associated with copper minerals.

[0003] Currently, the traditional flotation-following magnetic separation process for copper-cobalt skarn-type iron ore faces three major challenges: First, the iron mineral (magnetite) accounts for 50%-70% of the composition. To meet the liberation requirements of copper-cobalt minerals, excessive grinding is required to achieve a -38 μm particle size of over 95%, resulting in grinding power consumption of 80 kWh / t-120 kWh / t, with 60%-70% of the energy consumed in ineffective iron mineral processing. Simultaneously, the large adsorption of collectors by iron minerals increases reagent consumption by 30%-50%. Second, the copper-cobalt minerals are extremely fine (average 0.01-0.15 mm) and closely coexist with magnetite. Single grinding is insufficient to meet the liberation requirements, necessitating a staged grinding process for secondary fine grinding, further exacerbating energy consumption and equipment wear. Furthermore, there is a conflict between the grinding fineness required for copper-cobalt liberation and iron recovery. Third, micro-grinding generates a large amount of slime (<10 μm, accounting for 20%-30%). The slime preferentially adsorbs the collector and covers the surface of coarse particles, forming a slime capping effect. This results in difficulty in flotation bubble adhesion, low concentrate grade and recovery rate, high production cost, and difficulty in process control. Summary of the Invention

[0004] In view of the problems existing in the background technology, the present invention provides a method for recovering iron, copper and cobalt from copper-cobalt-rich skarn-type iron ore in stages, so as to solve the problems of high production cost and poor copper-cobalt separation index in the current recovery of iron, copper and cobalt from copper-cobalt-rich skarn-type iron ore in stages.

[0005] The specific details of the invention are as follows: This invention provides a method for recovering iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore cascades, the method comprising: Crushing and dry screening of copper-cobalt skarn-type iron ore; Dry magnetic separation is performed on the oversize material obtained from screening to recover coarse iron concentrate. The undersize material obtained from screening is subjected to wet ball milling and then used for flotation to obtain copper-cobalt mixed concentrate. The tailings produced by flotation are used for magnetic separation to obtain fine-grained iron concentrate. The copper-cobalt mixed concentrate is dried and granulated to form granular copper-cobalt mixed concentrate with a particle size of 10 mm-30 mm, and then combined with the tailings produced by the dry magnetic separation for bio-heap leaching to recover copper and cobalt.

[0006] Optionally, before crushing the copper-cobalt skarn-type iron ore, ultrasonic waves are used to vibrate and crack the iron ore, thereby creating fissures in the iron ore.

[0007] Optionally, the ultrasonic frequency is 15 kHz-40 kHz, the amplitude is 25 μm-60 μm, and the vibration time is 15 s-80 s.

[0008] Optionally, the iron ore, after being crushed, has an average particle size of 60 mm to 100 mm.

[0009] Optionally, the diameter of the sieve openings in the dry screening process is 10 mm to 50 mm.

[0010] Optionally, the belt moving speed of the dry magnetic separator is 4 m / s, and the magnetic field strength is 1500 Oe-2000 Oe.

[0011] Optionally, the grinding fineness of the wet ball milling process is -0.074 mm 70%-90%, and the grinding concentration is 65%-70%.

[0012] Optionally, the process of obtaining a copper-cobalt mixed concentrate by flotation includes: The pH of the slurry formed by wet ball milling is adjusted to 7-8. Then, collectors and frothers are added, and roughing and scavenging are carried out to obtain copper-cobalt mixed concentrate and flotation tailings. The collector is composed of O-isopropyl-N-ethyl thiocarbamate and sodium xanthate in a mass ratio of 1-3:1, and the dosage is 25 g / t-45 g / t. The foaming agent is pine oil, and the dosage is 10 g / t-25 g / t.

[0013] Optionally, the copper-cobalt mixed concentrate is dried and granulated to form granular copper-cobalt mixed concentrate with a particle size of 10 mm-30 mm, and combined with the tailings produced by dry magnetic separation for use in bioleaching to recover copper and cobalt, including: The granular copper-cobalt mixed concentrate and the tailings produced by dry magnetic separation are mixed at a mass ratio of 1:1-3 to construct a ore pile; The ore pile was circulated and sprayed with a dilute sulfuric acid solution until the pH of the recovered spray solution stabilized at 2-3. The ore heap was intermittently dripped with a leaching solution inoculated with 10%-30% Sulfobacillus sp. Biometek-GY-45 to leach valuable metals copper and cobalt.

[0014] Optionally, the depositary institution for the Sulfobacillus sp. Biometek-GY-45 is the China Center for Type Culture Collection, with a deposit date of February 23, 2023, and accession number M2023187.

[0015] This invention provides a method for the cascade recovery of iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore. The method includes: crushing and dry screening the copper-cobalt-rich skarn-type iron ore; performing dry magnetic separation on the oversize material obtained from screening to recover coarse iron concentrate; performing wet ball milling on the undersize material obtained from screening, and then using it for flotation to obtain a copper-cobalt mixed concentrate; using the tailings from the flotation to obtain a fine iron concentrate; and drying and granulating the copper-cobalt mixed concentrate to form granular copper-cobalt mixed concentrate with a particle size of 10 mm-30 mm, and combining it with the tailings from the dry magnetic separation for bio-heap leaching to recover copper and cobalt. Compared with the prior art, the present invention has the following advantages: This invention addresses the high iron mineral content in copper-cobalt skarn-type iron ore. It first processes the ore through crushing and dry screening, achieving early recovery of coarse iron concentrate through coarse and fine fractionation. Subsequently, a cascade recovery approach combining magnetic separation, flotation, and bio-heap leaching is employed to recover both copper-cobalt and fine iron concentrate. This eliminates the complex steps of traditional processes such as concentrate regrinding and multi-stage beneficiation, offering advantages such as a shorter process flow, simpler operation, and lower flotation reagent consumption. Furthermore, bio-heap leaching is low-temperature and low-consumption, making it more suitable for low-grade, complexly distributed skarn-type iron ore. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A process flow diagram of cascade recovery of iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore provided by an embodiment of the present invention is shown. Figure 2 A flow chart of a traditional process for recovering iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore is shown. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, any product that is the same as or similar to the present invention, derived by anyone under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of the present invention.

[0019] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0020] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0021] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] This invention provides a method for recovering iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore cascades, the method comprising: Crushing and dry screening of copper-cobalt skarn-type iron ore; Dry magnetic separation is performed on the oversize material obtained from screening to recover coarse iron concentrate. The undersize material obtained from screening is subjected to wet ball milling and then used for flotation to obtain copper-cobalt mixed concentrate. The tailings produced by flotation are used for magnetic separation to obtain fine-grained iron concentrate. The copper-cobalt mixed concentrate is dried and granulated to form granular copper-cobalt mixed concentrate with a particle size of 10 mm-30 mm, and then combined with the tailings produced by the dry magnetic separation for bio-heap leaching to recover copper and cobalt.

[0023] The recovery method provided by this invention eliminates the need for excessive grinding of all-grain ore. Copper-cobalt skarn-type iron ore is first crushed and dry-screened, and the coarse-fine iron concentrate is recovered quickly through coarse-fine fractionation. Subsequently, a cascade recovery approach using magnetic separation-flotation-bioheap leaching is adopted to recover copper-cobalt and fine-grained iron concentrate, eliminating the complex steps of concentrate regrinding and multi-stage beneficiation in traditional processes. This method has the advantages of a short process flow, simple operation, and low consumption of flotation reagents. Furthermore, bioheap leaching is low-temperature and low-consumption, making it more adaptable to low-grade and complexly distributed skarn-type iron ore.

[0024] In this embodiment, the copper-cobalt skarn-type iron ore, after crushing, has an average particle size of 60 mm-100 mm. The crushed ore material is then directly dry-screened, with the screen aperture diameter controlled between 10 mm and 50 mm. The coarse oversize material obtained from screening is then directly subjected to dry magnetic separation without further grinding. It can quickly recover coarse iron concentrate, avoid a large amount of iron minerals entering the subsequent grinding and flotation stages, and reduce the amount of ineffective processing from the source; the belt moving speed of dry magnetic separation is preferably 4 m / s-10 m / s, and the magnetic field strength is preferably 1500 Oe-2000 Oe.

[0025] In this embodiment, only the undersize fines are wet-milled, eliminating the need for excessive grinding of the entire ore. This significantly reduces the grinding volume, power consumption, and equipment wear, while simultaneously resolving the conflict between grinding fineness for copper-cobalt liberation and iron recovery. The preferred grinding fineness for wet ball milling is -0.074 mm 70%-90%, and the preferred grinding concentration is 65%-70%. Because coarse iron is separated in advance, the proportion of iron minerals in the flotation system formed after wet ball milling is low, effectively eliminating the adsorption and consumption of collectors by iron. This reduces the amount of flotation reagents used, improves separation efficiency, and results in a more stable grade of the copper-cobalt mixed concentrate obtained from flotation. Furthermore, the copper-cobalt mixed concentrate obtained by flotation is dried and granulated to 10-30mm. The granulated material is combined with the dry magnetic separation tailings for heap leaching. The heap has good air permeability and uniform spray liquid flow, avoiding fine mud clogging the pores and ore slime covering. The efficiency and stability of bioleaching are significantly improved. Deep recovery of copper and cobalt is achieved through bioleaching, taking into account the recovery of easily separated copper and cobalt as well as fine particles and encapsulated copper and cobalt. The total recovery rate of copper and cobalt is much higher than that of traditional single flotation or magnetic separation processes.

[0026] In this embodiment, iron recovery adopts a dual-path full recovery method, namely, dry magnetic separation of coarse iron concentrate from the screen and magnetic separation of fine iron concentrate from flotation tailings, to achieve full recovery of iron ore resources and avoid iron loss in the flotation and leaching stages. Copper and cobalt recovery adopts a tiered recovery mode of flotation pre-enrichment combined with bio-heap leaching for deep recovery. That is, after wet ball milling of the undersize fine material, copper and cobalt mixed concentrate is directly produced by flotation, which quickly enriches easily liberated copper and cobalt minerals and significantly reduces the volume of subsequent processing. The produced copper and cobalt mixed concentrate is dried and granulated into granular material, and then combined with dry magnetic separation tailings for bio-heap leaching. Microorganisms are used to efficiently leach fine particles and encapsulated copper and cobalt, achieving deep recovery of difficult-to-refine copper and cobalt, and finally obtaining copper and cobalt leachate. The overall recovery process does not involve excessive grinding and complex beneficiation, and has low reagent consumption and controllable costs.

[0027] In one specific embodiment, before crushing the copper-cobalt skarn-type iron ore, ultrasonic waves are used to vibrate and crack the iron ore, thereby creating fissures in the iron ore.

[0028] In specific implementation, the ultrasonic frequency can be controlled between 15 kHz and 40 kHz, the amplitude between 25 μm and 60 μm, and the vibration time between 15 s and 80 s. Because the ore becomes more brittle and easier to break after internal fissures are formed, the power consumption and equipment wear of subsequent crushing and ball milling can be significantly reduced, lowering production costs from the source. Furthermore, the fissures facilitate the individual liberation of tightly intergrowthed iron, copper, and cobalt minerals during subsequent crushing / grinding, solving the problem of dense and difficult-to-liberate iron and copper-cobalt intercalation in skarn-type iron ore, avoiding excessive fine grinding to meet liberation requirements. The fissures also fully expose iron minerals in coarse-grained ore, resulting in higher grade and recovery rate of coarse-grained iron concentrate recovered by dry magnetic separation, enabling early and efficient recovery. Simultaneously, the fissures significantly increase the specific surface area of ​​the ore, allowing leaching bacteria and sprayed acid to penetrate more easily into the ore interior, significantly improving the copper-cobalt bioleaching rate and extraction rate, especially suitable for the recovery of encapsulated and fine-grained copper-cobalt.

[0029] In one specific embodiment, the process of obtaining a copper-cobalt mixed concentrate by flotation includes: The pH of the slurry formed by wet ball milling is adjusted to 7-8. Then, collectors and frothers are added, and roughing and scavenging are carried out to obtain copper-cobalt mixed concentrate and flotation tailings.

[0030] In practice, the flotation of the copper-cobalt mixed concentrate employs a single roughing and a single scavenging process to obtain the copper-cobalt mixed concentrate and tailings from the flotation. Before flotation, the pH of the slurry is adjusted to 7-8. Then, a collector and a frother are added for roughing. The roughing collector consists of O-isopropyl-N-ethyl thiocarbamate and sodium xanthate in a mass ratio of 1-3:1, at a dosage of 25 g / t-45 g / t. The frother is pine oil, at a dosage of 10 g / t-25 g / t. After roughing, scavenging is further performed. During scavenging, appropriate amounts of collector and frother may be added as needed based on the copper-cobalt yield from the roughing.

[0031] In one specific embodiment, the copper-cobalt mixed concentrate is dried and granulated to form granular copper-cobalt mixed concentrate with a particle size of 10 mm-30 mm, and combined with tailings from dry magnetic separation for use in bioleaching to recover copper and cobalt, including: The granular copper-cobalt mixed concentrate and the tailings produced by dry magnetic separation are mixed at a mass ratio of 1:1-3 to construct a ore pile; The ore pile was circulated and sprayed with a dilute sulfuric acid solution until the pH of the recovered spray solution stabilized at 2-3. The ore pile was leached by circulating drip leaching with a leaching solution inoculated with 10%-30% Sulfobacillus sp. Biometek-GY-45 to extract valuable metals copper and cobalt.

[0032] In practice, the granulated copper-cobalt mixed concentrate and the tailings produced by dry magnetic separation are mixed at a mass ratio of 1:1-3 to construct a ore pile. Granulation treatment can effectively avoid fine mud clogging the pores and ensure uniform seepage of the spraying liquid. The ore pile is first pre-leached with dilute sulfuric acid solution to neutralize the acid-consuming gangue such as carbonates in the ore and provide an acidic growth environment for ferrooxidizobacterium. During the circulating spraying process, the pH of the leachate is adjusted in a timely manner to maintain it at 2.5-3 until the acid consumption of the ore pile system is balanced and the pH does not fluctuate significantly, at which point the pre-leaching ends.

[0033] In one specific embodiment, the depositary institution for the *Sulfobacillus sp.* Biometek-GY-45* is the China Center for Type Culture Collection, with a deposit date of February 23, 2023, and accession number M2023187. This bacterium is a mesophilic *Sulfobacillus sp.*, specifically used for the bioleaching of copper-cobalt sulfide ores. Before inoculation, the strain is activated and expanded using 9K iron-free medium at a constant temperature of 30 °C until it reaches the logarithmic growth phase (bacterial concentration ≥ 1 × 10⁻⁶). 8The mature bacterial solution was mixed with the pre-leaching equilibrated leachate at a ratio of 1:20 (V / M) to prepare a leaching solution inoculated with 10%-30% *Sulfobacillus ferrooxidans* sp. Biometek-GY-45. Intermittent drip / spray leaching was used for the leaching of valuable copper and cobalt. The leaching process maintained a moist and oxygen-rich environment in the ore pile to meet the aerobic metabolic needs of *Sulfobacillus ferrooxidans*.

[0034] To enable those skilled in the art to more clearly understand the present invention, the following embodiments will be used to provide a detailed description of a method for the cascade recovery of iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore.

[0035] Example 1 A skarn-type iron ore deposit in Anhui Province contains metal oxides and hydroxides, primarily magnetite, hematite / limonite, ilmenite, borosilicate, rutile, and zincite. Magnetite accounts for 44.94% of the total mineral composition, pyrrhotite for 3.12%, pyrite / cobalt-bearing pyrite for 2.88%, and chalcopyrite for 0.11%. Pyrrhotite and cobalt-bearing pyrite are densely intercalated, with some forming intergrowths encased by magnetite.

[0036] Figure 1 This invention provides a process flow diagram for the cascade recovery of iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore, as shown in the embodiments of the present invention. Figure 1 As shown, the specific steps are as follows: (1) Ultrasonic vibration cracking and crushing screening The ore is first subjected to ultrasonic vibration cracking pretreatment with an ultrasonic frequency of 35 kHz, an amplitude of 40 μm, and a vibration time of 60 s to create cracks inside the ore. It is then crushed to a particle size of 60 mm and dry screened with a screen aperture diameter of 10 mm to separate the material into oversize and undersize materials.

[0037] (2) Dry magnetic separation of oversize material for iron extraction The material on the 10 mm screen is recycled into coarse iron minerals using a dry magnetic separator. The magnetic separation belt speed is 4 m / s and the magnetic field strength is 1800 Oe to obtain coarse iron concentrate (iron concentrate 1). The magnetic separation tailings are stored for later use.

[0038] (3) Ball milling and flotation enrichment of copper and cobalt from undersize material The material under 10 mm sieve was processed by wet ball milling, with a grinding concentration of 65% and a grinding fineness of -0.074 mm accounting for 80%. After grinding, copper-cobalt mixed flotation was carried out, and the pH value of the flotation pulp was adjusted to 7.5. O-isopropyl-N-ethyl thiocarbamate and sodium xanthate (mass ratio 2:1, total dosage 25 g / t) were used as collectors, and pine oil was used as frother (dosage 15 g / t). After one roughing (5 min) and one scavenging (4 min), copper-cobalt mixed concentrate and flotation tailings were obtained.

[0039] (4) Granulation and combined heap leaching of copper-cobalt concentrate After filtration and dehydration, the copper-cobalt mixed concentrate was granulated to control the particle size to 25 mm. The granulated copper-cobalt concentrate and the dry magnetic separation tailings obtained in step (2) were combined and piled together at a mass ratio of 1:1. The mixture was first pre-neutralized by circulating dripping with dilute sulfuric acid to adjust the pH of the leachate to a stable level of 2.5. Then, mesophilic ferrous thiobacillus sp. Biometek-GY-45, which had been cultured at 30 °C, was added to the pre-leaching equilibrium solution at a ratio of 1:20 (V / M) for drip leaching. The leaching cycle was 40 days to obtain the copper-cobalt leachate.

[0040] (5) Magnetic separation of flotation tailings to extract fine iron The tailings from flotation were subjected to wet magnetic separation with a magnetic separation concentration of 15% and a magnetic field strength of 2000 Oe to obtain fine-grained iron concentrate (iron concentrate 2); the experimental results are shown in Table 1.

[0041] Table 1. Results of the New Process Flow Test

[0042] *Unit is g / L If traditional recycling processes are used (see...) Figure 2 The flowchart shown below illustrates the specific steps: After the ore is crushed to 12mm, it enters a ball mill for grinding to a fineness of -0.074mm (90%). A mixed flotation process is employed, consisting of one roughing and two scavenging stages. Lime is used as a roughing modifier, and the pH is adjusted to 8. O-isopropyl-N-ethylthiocarbamate and sodium xanthate (in a weight ratio of 2:1) are used as collectors. The roughing time is 6 minutes, and each of the two scavenging stages lasts 5 minutes. The collector dosage for both roughing and scavenging is 80 g / t. Pine oil is used as the frother, with a dosage of 15 g / t for both roughing and scavenging. The tailings from the scavenging are then subjected to magnetic separation to obtain iron concentrate and tailings. The magnetic field strength is 2000 Oe, and the magnetic separation concentration is 15%. After flotation, the mixed copper-cobalt concentrate was regrinded to 0.035 mm 90%, and lime was added as an inhibitor and O-isopropyl-N-ethyl thiocarbamate as a copper collector. Copper concentrate and cobalt concentrate were obtained by three cleaning processes. The recovery results are shown in Table 2.

[0043] Table 2 Test Results of Traditional Process Flow

[0044] The above comparison shows that, compared with the traditional process, the new process not only reduces the consumption of flotation reagents and grinding costs, but also greatly reduces the loss of copper and cobalt in iron concentrate, thus significantly improving the recovery rate of copper and cobalt.

[0045] Example 2 A skarn-type iron ore deposit in Shandong Province contains magnetite, hematite / limonite, and ilmenite as its main metallic minerals. Magnetite accounts for 52.12% of the total mass, pyrite for 5.44%, cobalt-bearing pyrite for 2.01%, and chalcopyrite for 0.32%. The particle size of pyrrhotite, chalcopyrite, and cobalt-bearing pyrite can reach -0.038 mm.

[0046] The specific steps are as follows: (1) Ultrasonic vibration cracking and crushing screening Before crushing, the ore is subjected to ultrasonic cracking with an ultrasonic frequency of 40 kHz, an amplitude of 36 micrometers, and a vibration time of 50s to create cracks in the ore. It is then crushed to a particle size of 60 mm and dry screened with a screen aperture diameter of 10 mm to separate the material into oversize and undersize materials. (2) Dry magnetic separation of oversize material for iron extraction The material on the 10mm sieve was recycled into coarse iron minerals using a dry magnetic separator. The belt speed was 3.5 m / s and the magnetic field was 2000 Oe. Coarse iron concentrate (iron concentrate 1) was obtained, and the tailings from the dry magnetic separation were stored for later use.

[0047] (3) Ball milling and flotation enrichment of copper and cobalt from undersize material The material under 10mm sieve was ground using a wet ball mill to a fineness of -0.074mm (85%) and a grinding concentration of 65%. After grinding, copper and cobalt were recovered by mixed flotation. The pH of the flotation pulp was adjusted to 7.8. O-isopropyl-N-ethyl thiocarbamate and sodium xanthate (mass ratio 3:1, total dosage 30 g / t) were used as collectors, and pine oil was used as a frother (dosage 25 g / t). After one roughing (5 min) and one scavenging (4 min), a copper-cobalt mixed concentrate and flotation tailings were obtained.

[0048] (4) Granulation and combined heap leaching of copper-cobalt concentrate After filtration and dehydration, the copper-cobalt mixed concentrate obtained in step (3) is granulated to control the particle size to 30 mm. The granulated copper-cobalt concentrate and the dry magnetic separation tailings obtained in step (2) are combined and piled together at a mass ratio of 1:3. The mixture is first pre-neutralized by circulating dripping with dilute sulfuric acid to adjust the pH of the leachate to a stable level of 2. Then, mesophilic sulfuric acid bacillus sp. Biometek-GY-45, which has been cultured at 30 °C, is added to the pre-leaching equilibrium solution at a ratio of 1:20 (V / M) for drip leaching. The leaching cycle is 60 days to obtain copper-cobalt leachate.

[0049] (5) Magnetic separation of flotation tailings to extract fine iron The tailings produced by flotation were subjected to wet magnetic separation with a magnetic separation concentration of 15% and a magnetic field strength of 2000 Oe to obtain fine-grained iron concentrate (iron concentrate 2); the test results are shown in Table 3.

[0050] Table 3 Results of the New Process Flow Test

[0051] *Unit is g / L Implemented using traditional processes: After the ore is crushed to 12mm, it enters a ball mill for grinding to a fineness of -0.074mm (90%). A mixed flotation process is employed, consisting of one roughing and two scavenging stages. Lime is used as a roughing modifier, and the pH is adjusted to 8. O-isopropyl-N-ethylthiocarbamate and sodium xanthate (in a weight ratio of 2:1) are used as collectors. The roughing time is 6 minutes, and each of the two scavenging stages lasts 5 minutes. The collector dosage for both roughing and scavenging is 80 g / t. Pine oil is used as the frother, with a dosage of 15 g / t for both roughing and scavenging. The tailings from the scavenging are then subjected to magnetic separation to obtain iron concentrate and tailings. The magnetic field strength is 2000 Oe, and the magnetic separation concentration is 15%. After the mixed copper-cobalt concentrate obtained by flotation was regrinded to 0.035 mm 90%, lime was added as an inhibitor and O-isopropyl-N-ethyl thiocarbamate as a copper collector. Copper concentrate and cobalt concentrate were obtained by three cleaning processes. The recovery results are shown in Table 2.

[0052] Table 4. Test Results of Traditional Process Flow

[0053] The above comparison shows that, compared with the traditional process, the new process can not only reduce the consumption of flotation reagents and grinding costs, but also significantly reduce the loss of copper and cobalt in tailings, and greatly reduce the loss of copper and cobalt in iron concentrate.

[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0055] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0056] The above provides a detailed description of a method for the cascade recovery of iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the above embodiments are only intended to help understand the method and core ideas of the invention. At the same time, those skilled in the art will recognize that, based on the ideas of the invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the invention.

Claims

1. A method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore, characterized in that, The method includes: Crushing and dry screening were performed on copper-cobalt skarn-type iron ore. Dry magnetic separation is performed on the oversize material obtained from screening to recover coarse iron concentrate; The undersize material obtained from screening is subjected to wet ball milling and then used for flotation to obtain copper-cobalt mixed concentrate. The tailings produced by flotation are used for magnetic separation to obtain fine-grained iron concentrate. The copper-cobalt mixed concentrate is dried and granulated to form granular copper-cobalt mixed concentrate with a particle size of 10 mm-30 mm, and then combined with the tailings produced by the dry magnetic separation for bio-heap leaching to recover copper and cobalt.

2. The method for recovering iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore cascades according to claim 1, characterized in that, Before crushing the copper-cobalt skarn-type iron ore, ultrasonic waves are used to vibrate and crack the iron ore, causing it to develop fissures.

3. The method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore according to claim 2, characterized in that, The ultrasonic frequency is 15 kHz-40 kHz, the amplitude is 25 μm-60 μm, and the vibration time is 15 s-80 s.

4. The method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore according to claim 1, characterized in that, The iron ore, after being crushed, has an average particle size of 60 mm-100 mm.

5. The method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore according to claim 1, characterized in that, The diameter of the sieve openings in the dry screening process is 10 mm to 50 mm.

6. The method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore according to claim 1, characterized in that, The dry magnetic separator has a belt moving speed of 4 m / s and a magnetic field strength of 1500 Oe-2000 Oe.

7. The method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore according to claim 1, characterized in that, The grinding fineness of the wet ball milling process is -0.074 mm, 70%-90%, and the grinding concentration is 65%-70%.

8. The method for recovering iron, copper, and cobalt from copper-cobalt-rich skarn-type iron ore cascades according to claim 1 or 7, characterized in that, The process of obtaining copper-cobalt mixed concentrate by flotation includes: The pH of the slurry formed by wet ball milling is adjusted to 7-8. Then, collectors and frothers are added, and roughing and scavenging are carried out to obtain copper-cobalt mixed concentrate and flotation tailings. The collector is composed of O-isopropyl-N-ethyl thiocarbamate and sodium xanthate in a mass ratio of 1-3:1, and the dosage is 25 g / t-45 g / t. The foaming agent is pine oil, and the dosage is 10 g / t-25 g / t.

9. The method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore according to claim 1, characterized in that, The copper-cobalt mixed concentrate is dried and granulated to form granular copper-cobalt mixed concentrate with a particle size of 10 mm-30 mm, and combined with the tailings produced by dry magnetic separation for use in bioleaching to recover copper and cobalt, including: The granular copper-cobalt mixed concentrate and the tailings produced by dry magnetic separation are mixed at a mass ratio of 1:1-3 to construct a ore pile; The ore pile was circulated and sprayed with a dilute sulfuric acid solution until the pH of the recovered spray solution stabilized at 2-3. The ore pile was leached by circulating drip leaching with a leaching solution inoculated with 10%-30% Sulfobacillus sp. Biometek-GY-45 to extract valuable metals copper and cobalt.

10. The method for recovering iron, copper, and cobalt from a cascade of copper-cobalt-rich skarn-type iron ore according to claim 9, characterized in that, The depositary institution for the Sulfobacillus sp. Biometek-GY-45 is the China Center for Type Culture Collection, the deposit date is February 23, 2023, and the accession number is M2023187.

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