Method for preparing high-nickel-cobalt concentrate from sulfur-cobalt rough concentrate

Abstract

The invention relates to the field of mineral separation, and discloses a method for preparing high-nickel-cobalt concentrate from sulfur-cobalt rough concentrate. The method comprises the steps that the cobalt sulfide rough concentrate is subjected to oxidizing roasting in the air atmosphere, and oxidizing roasting mineral powder is obtained; mixing the oxidized roasted mineral powder with limestone, boride and pulverized coal, and performing high-temperature reduction to obtain a reduction product; the reduction product is subjected to ore grinding treatment, and fine grinding minerals are obtained; and the fine grinding minerals are subjected to low-intensity magnetic separation, low-intensity magnetic concentrates and low-intensity magnetic tailings are obtained, and the low-intensity magnetic concentrates are high-nickel-cobalt concentrates. According to the method, through oxidizing roasting, reduction treatment, addition of the additive into the reduction raw materials, optimization of the reduction temperature and the like, the enrichment rate of cobalt and nickel is increased, and the high-nickel cobalt concentrate is obtained.

Description

Technical Field

[0001] This invention relates to the field of mineral processing, and more specifically to a method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate. Background Technology

[0002] The Panxi region is an important source of vanadium-titanium magnetite resources in my country. The ore produced there is rich in iron, vanadium, and titanium, and also contains associated elements such as cobalt, sulfur, nickel, and copper. After multi-stage crushing, grinding, and magnetic separation, the magnetic concentrate is separated from the non-magnetic tailings, yielding iron concentrate as the main product. The iron tailings are then processed through titanium beneficiation to recover titanium concentrate. During the extraction of ilmenite, to remove harmful sulfides, flotation is used to remove sulfides from the titanium rough concentrate before titanium ore flotation. The sulfides obtained from flotation desulfurization are called cobalt-sulfur rough concentrate, mainly composed of cobalt sulfides, and often accompanied by valuable metals such as nickel, copper, and iron. To achieve comprehensive resource utilization and reduce the environmental burden of solid waste treatment, this rough concentrate needs further processing to selectively recover elements such as nickel, cobalt, and iron.

[0003] In the processing of cobalt sulfide concentrate, industrial practice typically employs a high-temperature roasting-leaching process. This process effectively removes sulfur through high-temperature roasting and induces a transformation of the metallic phase, followed by acid leaching to extract and recover the target metal. However, this process suffers from drawbacks such as high energy consumption, large quantities of chemical reagents used, and a lengthy overall process flow, increasing processing costs and environmental burden.

[0004] Other technologies employ direct wet leaching, often using pressurized oxygen leaching or atmospheric pressure catalytic leaching, to decompose sulfide minerals in acidic media. However, in complex mineral systems, the selective leaching of valuable metals is not effective. In recent years, although separation methods such as solvent extraction and ion exchange have made progress, bottlenecks remain for leachates with high impurity content, including easy aging of extractants, lengthy separation processes, and high reagent costs.

[0005] Overall, there is still room for improvement in existing technologies for the recovery and utilization of cobalt sulfide concentrates. Summary of the Invention

[0006] In view of the above-mentioned problems in the prior art, the main objective of the present invention is to provide a method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate.

[0007] According to one aspect of the present invention, a method for preparing high-nickel-cobalt concentrate from cobalt sulfide crude concentrate is provided, the method comprising the following steps: The cobalt sulfide concentrate was oxidized and roasted in air to obtain oxidized roasted ore powder. The oxidized roasted mineral powder is mixed with limestone, borides, and coal powder, and then subjected to high-temperature reduction to obtain the reduction product. The reduction product is then subjected to grinding to obtain finely ground minerals. The finely ground minerals are subjected to weak magnetic separation to obtain weak magnetic concentrate and weak magnetic tailings. The weak magnetic concentrate is a high-nickel-cobalt concentrate.

[0008] According to one embodiment of the present invention, the oxidative calcination temperature is 600~800℃ and the calcination time is 3~4h.

[0009] According to one embodiment of the present invention, the mass ratio of the oxidized roasted ore powder, limestone, borides and coal powder is (80~90):(1~3):(1~3):(10~20).

[0010] According to one embodiment of the present invention, the boride is selected from at least one of B2O3 and boric acid.

[0011] According to one embodiment of the present invention, the coal powder is anthracite coal powder, and the proportion of the anthracite coal powder with a particle size of -200 mesh is above 95%.

[0012] According to one embodiment of the present invention, the mass percentage of CaO in the limestone is 40% to 50%.

[0013] According to one embodiment of the present invention, the high-temperature reduction is carried out at a temperature of 1200~1250℃ for 2~3 hours.

[0014] According to one embodiment of the present invention, the grinding process adopts a planetary mill, and the grinding time is 30-40 minutes.

[0015] According to one embodiment of the present invention, the method further includes recovering the coal powder from the weakly magnetic tailings by flotation and recycling the recovered coal powder for high-temperature reduction treatment, wherein the frother used in the flotation is No. 2 oil and the collector is kerosene.

[0016] According to one embodiment of the present invention, the high-nickel-cobalt concentrate contains more than 5% cobalt by mass and more than 10% nickel by mass.

[0017] Compared with the prior art, the method of preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate of the present invention has at least one of the following beneficial effects: The method of the present invention oxidizes and roasts the cobalt-sulfur crude concentrate in an air atmosphere, which can convert the sulfides therein into oxides that are easy to process in subsequent processing, and effectively remove some sulfur and volatile matter; by mixing the oxidized roasted ore powder with limestone, borides and coal powder and then reducing it at high temperature, the calcium oxide generated by the decomposition of limestone at high temperature can act as a strong slag-forming agent, preferentially reacting with the titanium, vanadium and other oxides and gangue such as silicon and aluminum inherent in the raw materials to form a stable and easily separable slag phase, realizing the initial enrichment and separation of nickel and cobalt, while the borides act as a flux, significantly reducing the melting point and viscosity of the slag system and improving the environment for the aggregation and growth of metal particles; the coal powder acts as a reducing agent, which, in the optimized slag phase environment, can reduce the oxidized cobalt, nickel and some iron to the metallic state, and promote the formation of nickel and cobalt into an alloy phase that is easy to magnetically separate. Through subsequent grinding and weak magnetic separation processes, the high-nickel-cobalt concentrate and tailings are efficiently separated. Attached Figure Description

[0018] 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.

[0019] Figure 1 A flowchart of a method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to an embodiment of the present invention is shown; Figure 2 A flowchart of a method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to another embodiment of the present invention is shown. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0023] The cobalt-sulfur concentrate produced from vanadium-titanium magnetite in the Panxi region is constrained by the properties of the raw ore in this area. In addition to sulfide minerals, the cobalt-sulfur concentrate also contains ilmenite and gangue minerals, resulting in low cobalt and nickel content and making recovery difficult. Extensive research by the inventors revealed that during the oxidative roasting-reduction process to prepare nickel-cobalt concentrate from the cobalt-sulfur concentrate, the presence of ilmenite in the concentrate leads to problems such as refractory sinter, low liquid phase content, and low cobalt and nickel recovery rates under a reducing atmosphere. Therefore, this invention improves the cobalt and nickel enrichment rate by adding additives to the raw materials and optimizing the reduction temperature, resulting in a high-nickel-cobalt concentrate.

[0024] According to one aspect of the present invention, a method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate is provided. For example... Figure 1-2 As shown, the method mainly includes the following steps: Step S1: Oxidize and roast the cobalt sulfide concentrate in air to obtain oxidized roasted ore powder; Step S2: Mix the oxidized roasted mineral powder with limestone, borides, and coal powder, and then reduce it at high temperature to obtain the reduction product; Step S3: Grind the reduction product to obtain finely ground minerals; Step S4: Perform weak magnetic separation on the finely ground minerals to obtain weak magnetic concentrate and weak magnetic tailings. The weak magnetic concentrate is the high-nickel-cobalt concentrate.

[0025] This invention discloses a method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate. The cobalt-sulfur crude concentrate is oxidatively roasted in an air atmosphere, converting the sulfides into oxides that are easily processed and effectively removing some sulfur and volatiles. The roasted ore powder is then mixed with limestone, borides, and coal powder and reduced at high temperature. The calcium oxide generated from the high-temperature decomposition of limestone acts as a powerful slag-forming agent, preferentially reacting with inherent titanium, vanadium oxides, and gangue such as silicon and aluminum in the raw material to form a stable and easily separable slag phase. This achieves the initial enrichment and separation of nickel and cobalt. Borides act as a flux, significantly reducing the melting point and viscosity of the slag system and improving the environment for metal particle aggregation and growth. Coal powder, as a reducing agent, under optimized slag phase conditions, can reduce oxidized cobalt, nickel, and some iron to a metallic state, promoting the formation of an alloy phase that is easily magnetically separated from nickel and cobalt. Subsequent grinding and weak magnetic separation processes achieve efficient separation of the high-nickel-cobalt concentrate from the tailings.

[0026] The steps of this method are described in detail below.

[0027] In step S1, the cobalt sulfide concentrate is oxidatively roasted in air to obtain oxidized roasted ore powder. The purpose of oxidative roasting is to convert the sulfides in the cobalt sulfide concentrate into oxides, while removing some sulfur and volatiles, creating favorable conditions for subsequent processing.

[0028] In some embodiments of the present invention, the oxidation roasting temperature can be controlled at 600~800℃, specifically, for example, 600℃, 650℃, 700℃, 750℃, or 800℃. The oxidation roasting time can be 3~4 hours, specifically, for example, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, or 4 hours. The sulfur dioxide produced by the oxidation roasting can be efficiently recovered through a matching flue gas treatment system and converted into industrial sulfuric acid.

[0029] Optionally, the cobalt sulfide concentrate can be dried before oxidative roasting, for example, by heating the cobalt sulfide concentrate to 80~120℃ and drying it for 30~60 minutes, so as to make the roasting process more stable and controllable.

[0030] In step S2, the oxidized roasted mineral powder is mixed with limestone, borides, and coal powder, and then subjected to high-temperature reduction to obtain the reduction product.

[0031] In some embodiments of the present invention, the mass ratio of oxidized roasted ore powder, limestone, borides, and coal powder is (80~90):(1~3):(1~3):(10~20). The CaO produced by the decomposition of limestone at high temperature acts as a slag-forming agent, effectively neutralizing the inherent acidic gangue such as silicon and aluminum in the raw materials, and preferentially combining with oxides such as titanium and vanadium to form a stable and easily separable perovskite slag phase, thereby achieving preliminary enrichment and separation of impurities. However, excessive limestone usage increases slag volume and reduction burden. Borides, as fluxing agents, can significantly reduce the melting point and viscosity of the slag system with small amounts, increase the liquid phase volume, improve the aggregation, growth, and settling environment of metal particles, and promote the separation of the cobalt-nickel-iron alloy phase from the slag phase. However, excessive borides increase costs and environmental burden. Coal powder must provide sufficient fixed carbon as a reducing agent to ensure that metal oxides are fully reduced to the metallic state. Using this ratio in conjunction with limestone slag formation and boride fluxing, efficient reduction and alloying of nickel and cobalt can be achieved under relatively mild reducing conditions.

[0032] In some embodiments of the present invention, the high-temperature reduction temperature is 1200~1250℃, and the time is 2~3 hours. Setting the reduction temperature to 1200~1250℃ has two advantages: firstly, this temperature allows the fixed carbon in the pulverized coal and the generated carbon monoxide to reduce the oxides of cobalt, nickel, and iron in the oxidized roasted ore powder to metallic elements, promoting their interdiffusion and forming a strongly magnetic iron-based alloy phase; secondly, this temperature range also facilitates the decomposition of limestone into calcium oxide, which reacts with the inherent acidic gangue such as silica and alumina in the raw materials, as well as oxides such as titanium and vanadium, to form a slag. The resulting slag phase has good fluidity and moderate interfacial tension with the molten metal, facilitating slag-metal separation. Simultaneously, the boride at this high temperature significantly reduces the overall viscosity and melting point of the slag system, ensuring that metal particles can fully aggregate, grow, and settle in the slag phase. The reduction time is set to 2~3 hours to ensure the reduction reaction proceeds fully.

[0033] In some embodiments of the present invention, the boride is selected from at least one of B2O3 and boric acid. When boric acid is used, it needs to be diluted with water before being sprayed into the mixture.

[0034] In some embodiments of the present invention, the coal powder is anthracite coal powder, and the proportion of anthracite coal powder with a particle size of -200 mesh is above 95%. Anthracite coal powder has a high fixed carbon content and low volatile matter. Using finer anthracite coal powder accelerates the reduction reaction kinetics and mass and heat transfer rates.

[0035] In some embodiments of the present invention, the mass percentage of CaO in the limestone is 40% to 50%, which provides sufficient active CaO while being economical.

[0036] In step S3, the reduction product is ground to obtain finely ground minerals.

[0037] For example, planetary milling is used for grinding, with a grinding time of 30-40 minutes. The intense shearing and impact of the planetary mill breaks down the brittle slag phase generated during reduction and fully dissociates the metal particles encapsulated within it. After planetary milling, the product forms a mixed system of magnetic metal particles and non-magnetic slag phases. This complete dissociation allows the magnetic particles to be efficiently captured by the magnetic field during subsequent weak magnetic separation, significantly improving the grade and recovery rate of high-nickel-cobalt concentrate.

[0038] In step S4, the finely ground minerals are subjected to weak magnetic separation to obtain weak magnetic concentrate and weak magnetic tailings. The weak magnetic concentrate is a high-nickel-cobalt concentrate.

[0039] Weak magnetic separation is a key step in achieving efficient separation of high-nickel-cobalt concentrate and tailings. Through weak magnetic separation, the magnetic portion (i.e., high-nickel-cobalt concentrate) and the non-magnetic portion (tailings) of finely ground minerals are separated.

[0040] Optionally, in some embodiments of the present invention, such as Figure 2 As shown, this method can also include recovering coal powder from weakly magnetic tailings by flotation, and recycling the recovered coal powder for high-temperature reduction treatment, thus achieving resource recycling and further cost reduction. The frother used in flotation can be No. 2 oil, with a dosage of 50 g / t; the collector is kerosene, with a dosage of 300 g / t. By optimizing the flotation conditions, the coal powder recovery rate can be improved.

[0041] The high-nickel cobalt concentrate obtained by the method described in the above embodiments contains more than 5% cobalt by mass and more than 10% nickel by mass.

[0042] The method of the present invention will be further described and illustrated below with reference to embodiments.

[0043] The chemical composition of the raw materials used in the following examples is shown in Table 1 below: Table 1. Chemical composition of raw materials (mass percentage, %)

[0044] Example 1 After drying, the cobalt-sulfur concentrate was oxidatively roasted in air at 700℃ for 3.5 h to obtain oxidized roasted ore powder. The oxidized roasted ore powder was mixed with limestone, B2O3, and anthracite powder at a mass ratio of 85:2:2:15 and reduced in a muffle furnace at 1225℃ for 2.5 h to obtain the reduction product. The reduction product was then ground in a planetary mill for 35 min. The finely ground mineral was then subjected to weak magnetic separation to obtain a weak magnetic concentrate and weak magnetic tailings. The weak magnetic concentrate is the high-nickel-cobalt concentrate. The weak magnetic tailings were used for flotation to recover anthracite, with No. 2 oil as the frother and kerosene as the collector. The frother dosage was 50 g / t, and the collector dosage was 300 g / t. The obtained flotation concentrate was returned as coal feedstock to the mixing step before reduction.

[0045] Example 2 After drying, the cobalt-sulfur concentrate was oxidatively roasted in air at 600℃ for 4 hours to obtain oxidized roasted ore powder. The oxidized roasted ore powder was mixed with limestone, B2O3, and anthracite powder at a mass ratio of 80:1:1:10 and reduced in a muffle furnace at 1200℃ for 3 hours to obtain the reduction product. The reduction product was then ground in a planetary mill for 30 minutes. The finely ground mineral was then subjected to weak magnetic separation to obtain a weak magnetic concentrate and weak magnetic tailings. The weak magnetic concentrate is the high-nickel-cobalt concentrate. The weak magnetic tailings were used for flotation to recover anthracite, with No. 2 oil as the frother and kerosene as the collector. The frother dosage was 50 g / t, and the collector dosage was 300 g / t. The obtained flotation concentrate was returned as coal feedstock to the mixing step before reduction.

[0046] Example 3 The cobalt-sulfur concentrate was dried and then oxidized and roasted in air at 800℃ for 3 hours to obtain oxidized roasted ore powder. The oxidized roasted ore powder was mixed with limestone, B2O3, and anthracite powder at a mass ratio of 90:3:3:20 and reduced in a muffle furnace at 1250℃ for 2 hours to obtain the reduction product. The reduction product was then ground using a planetary mill for 40 minutes. The finely ground mineral was then subjected to weak magnetic separation to obtain a weak magnetic concentrate and weak magnetic tailings. The weak magnetic concentrate is the high-nickel-cobalt concentrate. The weak magnetic tailings were used for flotation to recover anthracite, with No. 2 oil as the frother and kerosene as the collector. The frother dosage was 50 g / t, and the collector dosage was 300 g / t. The obtained flotation concentrate was returned as coal feedstock to the mixing step before reduction.

[0047] The nickel and cobalt contents of the high-nickel cobalt concentrates obtained in Examples 1-3 were tested, and the test results are shown in Table 2 below.

[0048] Table 2. Test results of nickel and cobalt content in high-nickel-cobalt concentrates from Examples 1-3.

[0049] As shown in Table 2, the high-nickel-cobalt concentrate obtained by the method of the present invention has a cobalt mass percentage of more than 5% and a nickel mass percentage of more than 10%. This method can obtain high-nickel-cobalt concentrate with high nickel and cobalt content and effectively achieves nickel and cobalt enrichment.

[0050] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of the present invention is limited to these examples; within the framework of the embodiments of the present invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention.

Claims

1. A method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate, characterized in that, Includes the following steps: The cobalt sulfide concentrate was oxidized and roasted in air to obtain oxidized roasted ore powder. The oxidized roasted mineral powder is mixed with limestone, borides, and coal powder, and then subjected to high-temperature reduction to obtain the reduction product. The reduction product is then subjected to grinding to obtain finely ground minerals. The finely ground minerals are subjected to weak magnetic separation to obtain weak magnetic concentrate and weak magnetic tailings. The weak magnetic concentrate is a high-nickel-cobalt concentrate.

2. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The oxidation calcination temperature is 600~800℃, and the calcination time is 3~4h.

3. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The mass ratio of the oxidized roasted mineral powder, limestone, borides, and coal powder is (80~90):(1~3):(1~3):(10~20).

4. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The boride is selected from at least one of B2O3 and boric acid.

5. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The coal powder is anthracite, and the proportion of anthracite particles with a size of -200 mesh is over 95%.

6. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The mass percentage of CaO in the limestone is 40% to 50%.

7. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The high-temperature reduction is carried out at a temperature of 1200~1250℃ for 2~3 hours.

8. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The grinding process uses a planetary mill, and the grinding time is 30-40 minutes.

9. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The method further includes recovering the coal powder from the weakly magnetic tailings by flotation and recycling the recovered coal powder for high-temperature reduction treatment. The frother used in the flotation is No. 2 oil and the collector is kerosene.

10. The method for preparing high-nickel-cobalt concentrate from cobalt-sulfur crude concentrate according to claim 1, characterized in that, The high-nickel-cobalt concentrate contains more than 5% cobalt by mass and more than 10% nickel by mass.

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