Device and method for reducing ferric oxide in red mud / copper-containing smelting slag through electromagnetic induction-arc plasma hydrogen cooperation

Abstract

The invention relates to the technical field of metal smelting, and provides a device and method for reducing ferric oxide in red mud / copper-containing smelting slag through electromagnetic induction-arc plasma hydrogen synergy, and the method comprises the steps that S1, pretreatment of the red mud / copper-containing smelting slag is conducted, specifically, the red mud / copper-containing smelting slag is dried till the red mud / copper-containing smelting slag contains water lt; 5%, crushing to 1t; 1 mm; s2, the red mud / copper-containing smelting slag treated in the step S1 and an additive are mixed according to the mass ratio of 100: (0.1-10), and a reaction mixture is obtained; s3, the reaction mixture is heated to 200-700 DEG C through electromagnetic induction, meanwhile, plasma hydrogen is added for a reaction in an oxygen-free environment, and the reaction time is 10-40 min; s4, cooling a reaction product obtained after the reaction in the step S3 to 1t; then, magnetic separation is carried out on the magnetic concentrate, and magnetic concentrate is obtained; and S5, carrying out acid dissolution or building material utilization on the tailings. Impurities (Al, Si, Ca and Ti) are not reduced, a gangue phase is kept, and the impurity content of magnetic concentrate is low.

Description

Technical Field

[0001] This application belongs to the field of metal smelting technology, and in particular relates to an apparatus and method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen. Background Technology

[0002] The annual discharge of red mud and copper smelting slag is >100 million tons and >30 million tons respectively, with Fe2O3 content of 20~50wt%. However, since the magnetic moment of Fe2O3 is zero, it cannot be directly magnetically separated, and the iron recovery rate is <10%.

[0003] Traditional high-temperature (temperature >1100℃) reduction requires coke powder / coal, which results in high energy consumption, slag melting, and impurities entering the iron phase, leading to low grades in subsequent magnetic separation. Using hydrogen to reduce ferric oxide has slow reduction kinetics, with extremely low reaction rates in the 200~700℃ low-temperature range, making it unacceptable industrially. Summary of the Invention

[0004] The purpose of this application is to provide an apparatus and method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen, aiming to solve the aforementioned problems in the existing treatment of red mud and copper smelting slag.

[0005] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen, comprising the following steps: S1. Pretreatment of red mud / copper smelting slag: dry to moisture content <5%, crush to <1 mm; S2. Mix the red mud / copper smelting slag treated in step S1 with the additive at a mass ratio of 100:0.1~10 to obtain a reaction mixture; S3. Heat the reaction mixture to 200~700℃ using electromagnetic induction, and simultaneously add plasma hydrogen to carry out the reaction in an oxygen-free environment for 10~40 min. S4. Cool the reaction product obtained after the reaction in step S3 to <100℃, and then perform magnetic separation to obtain magnetic concentrate; S5. The tailings are dissolved in acid or used in building materials.

[0006] As one possible design, the additive is CaF2 or Na2CO3.

[0007] As one possible design, the plasma hydrogen is formed by emitting hydrogen gas through a non-transfer arc plasma torch with a power of 20~80kW, an arc voltage of 100~200V, and a current of 200~400A.

[0008] As one possible design, the hydrogen flow rate is 50~150 Nm³ / h.

[0009] As one possible design, the electromagnetic induction heating is accomplished by an electromagnetic induction heating rotary kiln system, which includes an inclined rotary kiln with an electromagnetic induction coil wound around its exterior, and a heating rate of 15~30℃ / min; the inner wall of the rotary kiln is provided with a SiC-Ni composite coating.

[0010] As one possible design, the thickness of the SiC-Ni composite coating is 2~4 mm.

[0011] As one possible design, the rotary kiln has an inclination angle of 1~3° and a rotation speed of 0.5~4 rpm.

[0012] Secondly, this application provides an apparatus for the synergistic reduction of ferric oxide in red mud / copper smelting slag by electromagnetic induction-arc plasma hydrogen, comprising an electromagnetic induction heating rotary kiln and a plasma generating mechanism connected to each other, wherein the discharge end of the electromagnetic induction heating rotary kiln is connected to a magnetic separation mechanism.

[0013] As one possible design, the electromagnetic induction heating rotary kiln includes a kiln body made of heat-resistant stainless steel, with an electromagnetic induction coil wound around the outside of the kiln body and a SiC-Ni composite coating on the inside of the kiln body.

[0014] As one possible design, the plasma generating mechanism includes several non-transfer arc plasma torches, each of which is connected to the interior of the kiln body.

[0015] The beneficial effects of this invention are: 1. Low reaction temperature: a maximum of 850℃ is required, which is at least 250℃ lower than the temperature required for traditional coal-based reduction, and energy consumption is reduced by 30-40%.

[0016] 2. The red mud / copper smelting slag undergoes direct reaction and demagnetization from the moment it enters the electromagnetic induction heating zone. The entire process takes less than 40 minutes, and the Fe2O3 reduction rate is greater than 90%, thus achieving high efficiency.

[0017] 3. High selectivity: Impurities (Al, Si, Ca, Ti) are not reduced, maintaining the gangue phase, resulting in low impurities in the magnetic separation concentrate.

[0018] 4. By coupling the rotary kiln, electromagnetic induction heating, and plasma torch, continuous processing can be achieved, with a processing capacity of >5 t / h under a rotary kiln size of φ1.8m×20m.

[0019] 5. This process does not require the participation of coke powder / coal, CO2 emissions are reduced by more than 60%, and the tailings meet the requirements of GB 30760-2014 for building materials slag. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the apparatus used in this application for the synergistic reduction of ferric oxide in red mud / copper smelting slag by electromagnetic induction-arc plasma hydrogen.

[0022] The following are the labeling elements in the figure: 1-Electromagnetic induction heating rotary kiln; 2-Plasma generation mechanism. Detailed Implementation

[0023] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0025] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0026] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0027] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0028] The following description is based on specific embodiments.

[0029] Example 1 This embodiment discloses a device for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction and arc plasma hydrogen synergy, such as... Figure 1 As shown, it includes an electromagnetic induction heating rotary kiln 1 and a plasma generating mechanism 2 that are interconnected. The discharge end of the electromagnetic induction heating rotary kiln 1 is connected to a magnetic separation mechanism.

[0030] The electromagnetic induction heating rotary kiln 1 includes a kiln body with an inclination angle of 1-3° and a rotation speed of 0.5-4 rpm. The kiln body is made of heat-resistant stainless steel, and an electromagnetic induction coil is wound around the outside of the kiln body. The inside of the kiln body is coated with a SiC-Ni composite coating, which is generally about 3 mm thick. The plasma generating mechanism 2 includes two non-transfer arc plasma torches, each of which is connected to the inside of the kiln body.

[0031] This embodiment also discloses a method for the synergistic reduction of ferric oxide in red mud / copper smelting slag based on the aforementioned electromagnetic induction-arc plasma hydrogen synergistic reduction apparatus, as detailed below: S1. Obtain red mud, the composition of which is Fe2O3 38wt%, Al2O3 20wt%, SiO2 15wt%, CaO 12wt%, with the balance being impurities; dry and crush to below 0.5mm, and add Na2CO3 at a ratio of 100:5 and mix well. S2. The electromagnetic induction rotary kiln has dimensions of φ1.5m × 18m and an induction power of 200kW. The entire electromagnetic induction rotary kiln is sealed with nitrogen, with O2 < 0.5%. Two 50 kW non-transfer arc plasma torches are installed at the kiln head, and the H2 flow rate is 120 Nm³ / h. The average temperature of all materials (including red mud, Na2CO3, and H2) in the kiln is 720℃, and the residence time is 25 min.

[0032] S3. After the reducing slag cools, it undergoes 0.5 T dry magnetic separation, with an iron recovery rate of 82%, a total iron grade of 64% in the concentrate, and 4.2% iron in the tailings. Na2O is enriched in the tailings and can be used as a cement correcting raw material.

[0033] Example 2 This embodiment discloses an apparatus for the synergistic reduction of ferric oxide in red mud / copper smelting slag by electromagnetic induction-arc plasma hydrogen, comprising an electromagnetic induction heating rotary kiln 1 and a plasma generating mechanism 2 connected to each other, wherein the discharge end of the electromagnetic induction heating rotary kiln 1 is connected to a magnetic separation mechanism.

[0034] The electromagnetic induction heating rotary kiln 1 includes a kiln body with an inclination angle of 1-3° and a rotation speed of 0.5-4 rpm. The kiln body is made of 310S heat-resistant stainless steel, and an electromagnetic induction coil is wound around the outside of the kiln body. The parameters of the electromagnetic induction coil are 20 kHz / 100-300 kW, and the heating rate is ≥15℃ / min. The inside of the kiln body is coated with a SiC-Ni composite coating, which absorbs the induction field to generate secondary heating and improves the emissivity of red mud radiation. The thickness of the SiC-Ni composite coating is generally about 3 mm. The plasma generating mechanism 2 includes three non-transfer arc plasma torches, each of which is connected to the inside of the kiln body. The power of the non-transfer arc plasma torch is 20-80 kW, the arc voltage is 100-200 V, and the current is 200-400 A.

[0035] This embodiment also discloses a method for the synergistic reduction of ferric oxide in red mud / copper smelting slag based on the aforementioned electromagnetic induction-arc plasma hydrogen synergistic reduction apparatus, as detailed below: S1. Obtain copper smelting slag, the composition of which is Fe2O3 45wt%, Al2O3 10wt%, SiO2 25wt%, CaO 8wt%, Cu 0.6%, with the balance being impurities; dry and crush to below 1mm, without adding any additives; S2. The electromagnetic induction rotary kiln has dimensions of φ2 m × 24 m and an induction power of 300 kW. The entire electromagnetic induction rotary kiln is sealed with nitrogen, with O2 < 0.5%. Three 60 kW non-transfer arc plasma torches are installed at the kiln head, and the H2 flow rate is 150 Nm³ / h. The temperature of all materials (including copper smelting slag and H2) inside the kiln is increased from 650℃ (weak reduction) to 800℃ (deep reduction), with a residence time of 35 min.

[0036] S3. After the reduction slag cools, it undergoes 0.5 T dry magnetic separation, with an iron recovery rate of 65%, a total iron grade of 66% in the concentrate, and 3.8% iron in the tailings. Copper is not reduced and remains in the tailings, which facilitates subsequent acid leaching and recovery.

[0037] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen synergistic reduction, characterized in that, The method includes the following steps: S1. Pretreatment of red mud / copper smelting slag: dry to moisture content <5%, crush to <1 mm; S2. Mix the red mud / copper smelting slag treated in step S1 with the additive at a mass ratio of 100:0.1~10 to obtain a reaction mixture; S3. Heat the reaction mixture to 200~700℃ using electromagnetic induction, and simultaneously add plasma hydrogen to carry out the reaction in an oxygen-free environment for 10~40 min. S4. Cool the reaction product obtained after the reaction in step S3 to <100℃, and then perform magnetic separation to obtain magnetic concentrate; S5. The tailings are dissolved in acid or used in building materials.

2. The method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen as described in claim 1, characterized in that, The additive is CaF2 or Na2CO3.

3. The method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen as described in claim 1, characterized in that, The plasma hydrogen is formed by emitting hydrogen gas through a non-transfer arc plasma torch, with a power of 20~80kW, an arc voltage of 100~200V, and a current of 200~400A.

4. The method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen as described in claim 3, characterized in that, The flow rate of hydrogen is 50~150 Nm³ / h.

5. The method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen as described in claim 1, characterized in that, The electromagnetic induction heating is accomplished by an electromagnetic induction heating rotary kiln system, which includes an inclined rotary kiln. The outside of the rotary kiln is wound with an electromagnetic induction coil, and the heating rate is 15~30℃ / min. The inner wall of the rotary kiln is coated with a SiC-Ni composite coating.

6. The method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen as described in claim 5, characterized in that, The thickness of the SiC-Ni composite coating is 2~4mm.

7. The method for the synergistic reduction of ferric oxide in red mud / copper smelting slag using electromagnetic induction-arc plasma hydrogen as described in claim 5, characterized in that, The rotary kiln has an inclination angle of 1~3° and a rotation speed of 0.5~4 rpm.

8. A device for the synergistic reduction of ferric oxide in red mud / copper smelting slag by electromagnetic induction and arc plasma hydrogen synergistic reduction, characterized in that, The device includes an electromagnetic induction heating rotary kiln and a plasma generating mechanism that are interconnected, and the discharge end of the electromagnetic induction heating rotary kiln is connected to a magnetic separation mechanism.

9. The apparatus for the synergistic reduction of ferric oxide in red mud / copper smelting slag by electromagnetic induction-arc plasma hydrogen synergistic reduction according to claim 8, characterized in that, The electromagnetic induction heating rotary kiln includes a kiln body made of heat-resistant stainless steel, with an electromagnetic induction coil wound around the outside of the kiln body and a SiC-Ni composite coating on the inside of the kiln body.

10. The apparatus for the synergistic reduction of ferric oxide in red mud / copper smelting slag by electromagnetic induction-arc plasma hydrogen synergistic reduction according to claim 9, characterized in that, The plasma generating mechanism includes several non-transfer arc plasma torches, each of which is connected to the interior of the kiln body.

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