Efficient utilization method of copper-iron sulfide ore

Abstract

The embodiment of the invention discloses an efficient utilization method of copper-iron sulfide ore. The method comprises the following steps: S1, mixing the copper-iron sulfide ore with magnesium oxide to obtain a mixed material; s2, heating the mixed material to a set temperature in an air or oxygen atmosphere for roasting, and collecting sulfur dioxide gas in tail gas by using a magnesium hydroxide solution to obtain magnesium sulfate; collecting a roasted solid-phase product; s3, washing the roasted solid-phase product with water to obtain a copper-iron oxide intermediate product; and S4, the copper-iron oxide intermediate product is reduced in the hydrogen atmosphere, and a copper and iron elementary substance mixture or a copper-iron alloy is obtained. The process flow is simplified, the energy consumption is low, the controllability of hydrogen reduction and the synergistic extraction of copper and iron resources are realized, the emission of a large amount of sulfur dioxide in the traditional pyrogenic process is avoided, and the method has remarkable environmental protection and economic benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal smelting, and particularly relates to a method for efficiently utilizing copper-iron sulfide ore. Background Art

[0002] As the most abundant and widely distributed copper-containing mineral in nature, chalcopyrite exists in the form of polymetallic sulfide ore associated with pyrite in nature. As the most abundant copper-iron symbiotic sulfide mineral globally, the copper reserves of polymetallic sulfide ore account for more than 70% of the world's exploitable copper resources, and the iron element content can reach about 30%. It is a copper-iron composite ore deposit with strategic resource value. With the gradual depletion of high-grade ore bodies, how to achieve the coordinated development of copper and iron resources has become an important topic in the metallurgical field.

[0003] In the existing smelting system, the coordinated extraction of copper, iron, and sulfur in sulfide ore still faces systematic technical bottlenecks. Although pyrometallurgy can obtain blister copper with a copper content of 98%, more than 30% of the iron elements in the ore are locked in the slag due to high-temperature silicate reaction. The iron grade in such iron-containing waste slag is only 40% - 45% and the occurrence form is complex, making it difficult to recycle economically. The global annual loss of iron resources due to this is more than 20 million tons. In hydrometallurgy, due to the kinetic difference in copper and iron leaching, more than 60% of the iron is leached synchronously with copper. In the subsequent extraction process, the copper-iron separation coefficient is less than 10, and finally 80% of the iron enters the tail slag in the form of iron hydroxide precipitation, resulting in a sharp drop in resource value.

[0004] The problems of process energy consumption and sulfur pollution also restrict sustainable development. Pyrometallurgy consumes 1.8 - 2.2 tons of standard coal per ton of copper smelted, and 40% of the energy consumption is used to maintain the molten state of the iron silicate system. Although the energy consumption of the hydrometallurgical process is reduced, high-cost oxidants such as hydrogen peroxide need to be continuously added in the leaching process, and additional energy consumption for electrodialysis is required for the reuse of iron ions. More seriously, the sulfur dioxide concentration in pyrometallurgical flue gas is generally lower than 8%, which cannot meet the concentration threshold (>10%) of the contact sulfuric acid process, resulting in the direct emission of more than 1.5 million tons of sulfur dioxide from the global copper smelting system every year. And more than 90% of the ferric sulfate waste liquid generated by hydrometallurgy needs to be neutralized due to copper ion pollution, which not only wastes sulfur resources but also generates new solid waste. Summary of the Invention

[0005] In view of this, some embodiments disclose a method for efficiently utilizing copper-iron sulfide ore, including the steps of:

[0006] S1. Mix copper-iron sulfide ore with magnesium oxide to obtain a mixed material;

[0007] S2. Heat the mixed material in an air or oxygen atmosphere to a set temperature for roasting, collect sulfur dioxide gas in the tail gas with a magnesium hydroxide solution to obtain magnesium sulfate; collect the solid-phase product of roasting;

[0008] S3. Wash the solid product to obtain an intermediate copper-iron oxide product;

[0009] S4. Reduce the intermediate copper-iron oxide product in a hydrogen atmosphere to obtain a mixture of metallic copper and metallic iron or a copper-iron alloy. Further, in the method for efficient utilization of copper-iron sulfide ore disclosed in some embodiments, in step S2, the roasting temperature is set to 500-700 °C, and the heat preservation time is set to 30-120 min.

[0010] In the method for efficient utilization of copper-iron sulfide ore disclosed in some embodiments, step S3 includes:

[0011] Grind the solid product, add the obtained powder to water, and dissolve magnesium sulfate in the water;

[0012] Filter and collect the undissolved part in the solid product to obtain an intermediate copper-iron oxide product;

[0013] Dry the intermediate copper-iron oxide product.

[0014] In the method for efficient utilization of copper-iron sulfide ore disclosed in some embodiments, the copper-iron oxide is dried at 70-100 °C, and the drying time is 180-360 min.

[0015] In the method for efficient utilization of copper-iron sulfide ore disclosed in some embodiments, step S4 includes:

[0016] Place the intermediate copper-iron oxide product in a tubular furnace, heat it to a reduction temperature of 700-950 °C in a hydrogen atmosphere, with a heating rate of 5-10 °C / min and a hydrogen flow rate of 30-120 mL / min;

[0017] Perform reduction at a reduction temperature of 700-950 °C, with a reduction heat preservation time of 30-120 min, to obtain a mixture of metallic copper and metallic iron.

[0018] In the method for efficient utilization of copper-iron sulfide ore disclosed in some embodiments, step S4 includes:

[0019] Form the intermediate copper-iron oxide product into a powder or a green body;

[0020] Place the intermediate copper-iron oxide product in a tubular furnace, heat it to a reduction temperature of 700-950 °C in a hydrogen atmosphere, with a heating rate of 5-10 °C / min and a hydrogen flow rate of 30-120 mL / min, and keep it at the reduction temperature of 700-950 °C for 30-120 min; then switch to an argon atmosphere, with an argon flow rate of 80-120 mL / min, and heat it at a heating rate of 5-20 °C / min in the argon atmosphere to 1100-1650 °C for alloying, with a heat preservation time of 120-300 min, to obtain a copper-iron alloy.

[0021] The efficient utilization method of copper-iron sulfide ore disclosed in the embodiments of the present invention has at least the following beneficial technical effects:

[0022] 1. The process flow is simplified and the energy consumption is low. The overall process adopts a two-step method of "oxidative roasting - hydrogen reduction", abandoning high-energy-consuming and highly polluting links such as traditional pyrometallurgical smelting, converting, or hydrometallurgical acid leaching and electrolysis. It not only avoids the acidic wastewater generated by the hydrometallurgical process and the large amount of waste slag generated by pyrometallurgical converting, but also realizes clean production because the by-product of hydrogen reduction is only water. In addition, magnesium oxide is inexpensive, easy to obtain and preserve. It not only plays a role in sulfur fixation during roasting, and no corrosive hydrogen sulfide gas is generated in the product; magnesium sulfate generated by magnesium oxide has high solubility in water, which is convenient to wash away, and its alkaline property can also inhibit the volatilization loss of metals, improve the pore structure of the material, and the recycling of magnesium hydroxide absorbent further reduces reagent consumption and enhances the economic efficiency of the process. Through the optimization of chemical reaction paths and process integration, this technology has achieved systematic breakthroughs in aspects such as the full recovery of sulfur resources, the flexible preparation of metal products, energy consumption and pollution control, providing a new path of high efficiency and low carbon for green metallurgy.

[0023] 2. The controllability of hydrogen reduction and the coordinated utilization of copper and iron resources; copper oxide and iron oxide in the roasted product can be precisely regulated through hydrogen reduction. Utilizing the difference in their reduction temperatures, single metals can be selectively obtained through stepwise reduction. Copper is preferentially reduced at low temperatures and iron is reduced subsequently at high temperatures, or copper-iron alloy can be directly prepared through condition optimization, eliminating the cumbersome process of separating impurities in multiple steps in the traditional smelting process; realizing the coordinated utilization of copper and iron resources in polymetallic sulfide ores, and solving the bottleneck problem of the difficult extraction and utilization of iron resources in traditional processes and the stacking of copper slag.

[0024] 3. The dual fixation and closed-loop resource utilization of sulfur; in the roasting stage, magnesium oxide directly converts part of the sulfur in chalcopyrite into magnesium sulfate for fixation, and a small amount of sulfur dioxide escaping is absorbed by the alkaline solution of magnesium hydroxide and further oxidized into magnesium sulfate, forming a closed-loop recovery system for sulfur elements, with remarkable environmental benefits; this dual sulfur fixation mechanism not only avoids the large emission of sulfur dioxide in the traditional pyrometallurgical process and eliminates the complex tail gas desulfurization device, but also recovers sulfur in the form of high-value-added magnesium sulfate, greatly improving the utilization rate of mineral resources. Description of the Drawings

[0025] Figure 1 Flow chart of the efficient utilization method of copper-iron sulfide ore disclosed in some embodiments;

[0026] Figure 2 SEM images of copper and iron metal products prepared in Example 1;

[0027] Figure 3 SEM images of copper-iron alloy products prepared in Example 2. Detailed Embodiments

[0028] As used herein, the term "embodiment" in the specific sense, and any embodiment described as "exemplary" need not be construed as superior to or better than other embodiments. For the performance index tests in the embodiments of the present invention, unless otherwise specified, conventional test methods in the art are adopted. It should be understood that the terms described in the embodiments of the present invention are merely for describing specific embodiments and are not intended to limit the content disclosed in the embodiments of the present invention.

[0029] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by those of ordinary skill in the technical field to which the embodiments of the present invention pertain; other test methods and technical means not specifically noted in the embodiments of the present invention refer to the test methods and technical means commonly adopted by those of ordinary skill in the art.

[0030] The terms "substantially" and "about" as used herein are used to describe minor fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data presented or expressed in a range format herein is used only for convenience and brevity and should therefore be interpreted flexibly as including not only the explicitly recited values that are the limits of the range, but also all the individual values or sub-ranges subsumed within that range. For example, the numerical range of "1 to 5%" should be interpreted as including not only the explicitly recited values of 1% to 5%, but also the individual values and sub-ranges within the indicated range. Thus, within this numerical range, individual values such as 2%, 3.5%, and 4% are included, and sub-ranges such as 1% to 3%, 2% to 4%, and 3% to 5% etc. This principle also applies to ranges that list only one numerical value. In addition, such an interpretation applies regardless of the width of the range or the characteristics described.

[0031] In this document, including in the claims, conjunctive words such as "comprising", "including", "carrying", "having", "containing", "involving", "accommodating", etc. are understood to be open-ended, that is, meaning "including but not limited to". Only the conjunctive words "consisting of" and "composed of" are closed conjunctive words.

[0032] To better illustrate the content of the present invention, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that the present invention can be implemented without some of these specific details. In the embodiments, some methods, means, instruments, devices, etc. well-known to those skilled in the art are not described in detail in order to highlight the gist of the present invention.

[0033] On the premise of no conflict, the technical features disclosed in the embodiments of the present invention can be arbitrarily combined, and the obtained technical solutions belong to the content disclosed in the embodiments of the present invention.

[0034] In some embodiments, as Figure 1 shown, the method for the efficient utilization of copper-iron sulfide ore includes the steps of:

[0035] S1. Mix the copper-iron sulfide ore with magnesium oxide to obtain a mixed material; generally, the added magnesium oxide tries to fix all sulfur.

[0036] S2. Heat the mixed material in an air or oxygen atmosphere to a set temperature for oxidative roasting, collect the sulfur dioxide gas in the tail gas with a magnesium hydroxide solution to obtain magnesium sulfate; collect the solid-phase product of the roasting; usually, the roasting temperature is set at 500-700 °C, and the heat preservation time is set at 30-120 min.

[0037] S3. Wash the solid-phase product with water to obtain a copper-iron oxide intermediate product; generally, grind the solid-phase product, add the obtained powder to water, and magnesium sulfate dissolves in water to form a magnesium sulfate solution; filter to collect the undissolved part in the solid-phase product to obtain a copper-iron oxide intermediate product; the copper-iron oxide intermediate product is subjected to a drying treatment; generally, the copper-iron oxide is dried at 70-100 °C, and the drying time is 180-360 min.

[0038] S4. Reduce the copper-iron oxide intermediate product in a hydrogen atmosphere to obtain metallic copper and metallic iron. Usually, by controlling different reduction conditions to treat the dried metal oxide intermediate product, a mixture of metallic copper and metallic iron, or a copper-iron alloy can be prepared.

[0039] In the method for the efficient utilization of copper-iron sulfide ore disclosed in some embodiments, step S4 includes: placing the copper-iron oxide intermediate product in a tube furnace, heating it to a reduction temperature of 700-950 °C in a hydrogen atmosphere with a hydrogen flow rate of 30-120 mL / min, and the heating rate is 5-10 °C / min; heating to the reduction temperature of 700-950 °C for reduction, and the reduction heat preservation time is 30-120 min to obtain a mixture of metallic copper and metallic iron.

[0040] The efficient utilization method of copper-iron sulfide ore disclosed in some embodiments, step S4 includes: forming the copper-iron oxide intermediate product into a powder or a green body; placing the copper-iron oxide intermediate product in a tubular furnace, heating it to a reduction temperature of 700-950 °C in a hydrogen atmosphere with a hydrogen flow rate of 30-120 mL / min, and the heating rate is 5-10 °C / min; heating to the reduction temperature of 700-950 °C for reduction, and the reduction holding time is 30-120 min; then switching to an argon atmosphere, with an argon flow rate of 80-120 mL / min, heating to a temperature of 1100-1650 °C at a heating rate of 5-20 °C / min for alloying, and the holding time is 120-300 min to obtain a copper-iron alloy.

[0041] The following further exemplarily illustrates the technical details in conjunction with embodiments.

[0042] Example 1

[0043] The efficient utilization method of copper-iron sulfide ore disclosed in Example 1 includes:

[0044] Placing copper sulfide ore powder and magnesium oxide in a mortar and grinding and mixing them at a molar ratio of 4:1, and adding the ground mixture to a mixer for sufficient mixing;

[0045] The mixed material is evenly spread on a tablet die and pressed into a cylindrical green body with a diameter of 11 mm and a height of 5 mm under a pressure of 6 MPa. Place the green body on a corundum plate and put it in a muffle furnace. Set the temperature program of the muffle furnace, first raise the temperature to 700 °C at a heating rate of 10 °C / min in an air atmosphere, hold for 60 min at 700 °C, and absorb the sulfur dioxide gas in the tail gas with a magnesium hydroxide alkaline solution; after the holding ends, naturally cool to room temperature and collect the solid roasting product;

[0046] Grind the roasting product, add water for washing, and stir for 10 min under a magnetic stirrer; perform suction filtration on the stirred washing solution to obtain copper and iron oxides, and place them in an oven to dry at 70 °C for 180 min;

[0047] Place the dried product in a tubular furnace, raise the temperature to 950 °C at a heating rate of 10 °C / min in a hydrogen atmosphere, and the hydrogen flow rate is 100 mL / min; hold for 30 min at 950 °C to obtain a copper and iron metal mixture, and the SEM morphology of this mixture sample is as Figure 2 shown.

[0048] Example 2

[0049] The efficient utilization method of copper-iron sulfide ore disclosed in Example 2 includes:

[0050] The copper sulfide ore powder and magnesium oxide are placed in a mortar and ground and mixed at a molar ratio of 4:1. The ground mixture is added to a mixer and thoroughly mixed;

[0051] The mixed material is evenly spread in a tablet press mold and pressed into a cylindrical green body with a diameter of 11 mm and a height of 5 mm under a pressure of 6 MPa; the green body is placed on a corundum sheet and placed in a muffle furnace. Set the temperature program of the muffle furnace. First, heat it to 700 °C at a heating rate of 10 °C / min in an air atmosphere, keep it at 700 °C for 1 h, and absorb the sulfur dioxide gas in the tail gas with a magnesium hydroxide solution; after the heat preservation is completed, cool it to room temperature naturally, and collect the solid calcination product;

[0052] The calcination product is ground, water is added for washing, and stirred for 10 min under a magnetic stirrer; the stirred washing solution is filtered by suction to obtain copper and iron oxides, which are placed in an oven and dried at 70 °C for 180 min;

[0053] The dried product is pressed into a cylindrical green body with a diameter of 11 mm and a height of 5 mm under a pressure of 6 MPa and placed in a tube furnace. It is heated to the reduction temperature of 950 °C at a heating rate of 10 °C / min in a hydrogen atmosphere, kept at this temperature for 30 min, and the hydrogen flow rate is 100 mL / min; then it is switched to an argon atmosphere, heated to 1550 °C at a heating rate of 10 °C / min for alloying, and the holding time is 120 min to obtain a copper-iron alloy. The SEM morphology of this copper-iron alloy sample is as Figure 3 shown, Figure 3 at the "+1" position point in the figure, the mass content of iron is 71.86 wt.%, and the mass content of copper is 28.14 wt.%.

[0054] The efficient utilization method of copper-iron sulfide ore disclosed in the embodiments of the present invention generally adopts a two-step method of "oxidative roasting - hydrogen reduction", abandoning high-energy-consuming and highly polluting links such as traditional pyrometallurgical smelting, converting, or hydrometallurgical acid leaching and electrolysis. It not only avoids the acidic wastewater generated by the hydrometallurgical method and the generation of a large amount of waste slag in the pyrometallurgical converting process, but also realizes clean production because the by-product of hydrogen reduction is only water. In addition, magnesium oxide is inexpensive, easy to obtain and preserve. In roasting, it not only plays a role in sulfur fixation, and the generated magnesium sulfate has a large solubility in water and is easy to wash away. Its alkaline property can also inhibit the volatilization loss of metals and improve the pore structure of the material. The recycling of the magnesium hydroxide absorbent further reduces the reagent consumption and enhances the process economy. The copper oxide and iron oxide in the roasted product can be precisely regulated through hydrogen reduction. Utilizing the difference in their reduction temperatures, single metals can be selectively obtained through stepwise reduction. Copper is preferentially reduced at low temperature and iron is reduced subsequently at high temperature. Or a copper-iron alloy can be directly prepared through condition optimization, eliminating the cumbersome process of separating impurities in multiple steps in the traditional smelting process. In the roasting stage, magnesium oxide directly converts part of the sulfur in chalcopyrite into magnesium sulfate for fixation, and a small amount of sulfur dioxide gas escaping is absorbed by the magnesium hydroxide alkaline solution and further neutralized into magnesium sulfate, forming a closed-loop recovery system for sulfur elements. This dual sulfur fixation mechanism not only avoids the large emission of sulfur dioxide in the traditional pyrometallurgical process, avoids the generation of corrosive hydrogen sulfide gas, and eliminates the complex tail gas desulfurization device, but also recovers sulfur in the form of high-value magnesium sulfate, greatly improving the utilization rate of mineral resources.

[0055] The technical solutions disclosed in the embodiments of the present invention and the technical details disclosed in the embodiments are only exemplary explanations of the inventive concept of the present invention, and do not constitute a limitation on the technical solutions of the embodiments of the present invention. Any conventional changes, substitutions, or combinations made to the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the protection scope of the claims of the present invention.

Claims

1. A method for the efficient utilization of copper-iron sulfide ore, characterized in that, Including the steps: S1. Mix copper-iron sulfide ore with magnesium oxide to obtain a mixed material; S2. Heat the mixed material to a set temperature in an air or oxygen atmosphere for roasting, collect sulfur dioxide gas in the tail gas with magnesium hydroxide to obtain magnesium sulfate; collect the solid-phase product of roasting; S3. Wash the solid-phase product with water to obtain a copper-iron oxide intermediate product; S4. Reduce the copper-iron oxide intermediate product in a hydrogen atmosphere to obtain a mixture of metallic copper and metallic iron or a copper-iron alloy.

2. The method for efficient utilization of copper-iron sulfide ore according to claim 1, characterized in that In step S2, the roasting temperature is set to 500 - 700 °C, and the heat preservation time is set to 30 - 120 min.

3. The efficient utilization method of copper-iron sulfide ore according to claim 1, characterized in that Step S3 includes: Grind the solid-phase product, add the obtained powder to water, and magnesium sulfate dissolves in water; Filter by suction to collect the undissolved part in the solid-phase product to obtain a copper-iron oxide intermediate product; Dry the copper-iron oxide intermediate product.

4. The method for efficient utilization of copper-iron sulfide ore according to claim 3, wherein The copper-iron oxide is dried at 70 - 100 °C, and the drying time is 180 - 360 min.

5. The method for efficient utilization of copper-iron sulfide ore according to claim 1, characterized in that, Step S4 includes: Place the copper-iron oxide intermediate product in a tubular furnace, heat it to a reduction temperature of 700 - 950 °C in a hydrogen atmosphere, and the heating rate is 5 - 10 °C / min; The copper-iron oxide intermediate product is reduced in a hydrogen atmosphere at a reduction temperature of 700 - 950 °C, and the reduction heat preservation time is 30 - 120 min to obtain a mixture of metallic copper and metallic iron.

6. The method for efficient utilization of copper-iron sulfide ore according to claim 5, characterized in that, The hydrogen flow rate is 30 - 120 mL / min.

7. The method for efficient utilization of copper-iron sulfide ore according to claim 1, wherein Step S4 includes: Form the copper-iron oxide intermediate product into a powder or a green body; Place the copper-iron oxide intermediate product in a tubular furnace, heat it to a reduction temperature of 700 - 950 °C at a heating rate of 5 - 10 °C / min in a hydrogen atmosphere, and keep it warm for 30 - 120 min; then switch to an argon atmosphere, heat it at a heating rate of 5 - 20 °C / min in the argon atmosphere, heat to a temperature of 1100 - 1650 °C for alloying, and the heat preservation time is 120 - 300 min to obtain a copper-iron alloy.

8. The method for efficient utilization of copper-iron sulfide ore according to claim 7, characterized in that, The argon flow rate is 80 - 120 mL / min, and the hydrogen flow rate is 30 - 120 mL / min.

Images