Plasma-side-blown coupled smelting furnace and smelting method thereof

Abstract

The application provides a plasma-side blowing coupled smelting furnace and a smelting method thereof, comprising a furnace body, a partition wall, a melting zone, a reduction sulfuration zone, a clarification separation zone, a feeding device, a plasma torch and a side blowing port; the core innovation is that a functional partitioned refractory material feeding port and a conventional material feeding port are arranged at the top of the melting zone; a transfer type plasma torch is arranged near the refractory material feeding port, and the function is to perform a high enthalpy phase change melting task and convert solid refractory material into superheated melt; the side blowing port is immersed in the molten pool, and the function is to perform a macroscopic homogenization and heat transfer task and disperse the superheated melt to the whole molten pool as a high-efficiency heat transfer medium; through a new process mode of "fixed point phase change and macroscopic transfer", the application realizes precise energy delivery and decoupling of thermodynamics and chemical processes, and has unexpected technical effects of significantly reducing energy consumption, improving metal recovery rate and enhancing process stability when treating complex materials.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal pyrometallurgy technology, specifically a plasma-side-blown coupled smelting furnace and its smelting method. Background Technology

[0002] The core challenge in efficiently recovering nickel metal from nickel-containing solid wastes such as sapropelic laterite nickel ore, spent catalysts, or stainless steel slag lies in overcoming the locking effect of the high-melting-point oxide matrix on the target metal. In these materials, nickel is often encapsulated within... , , In the crystal structure composed of refractory oxides, the solid-liquid phase transition energy barrier is extremely high, and traditional smelting technology faces a systemic bottleneck.

[0003] Oxygen-enriched side-blown smelting, as a mainstream process, uses an immersion lance to blow oxygen-enriched air into the molten pool, achieving strong stirring and enhanced reaction. This technology is well-suited for conventional materials, but its thermodynamic nature relies on the macroscopic exothermic reaction of fossil fuel combustion, which has inherent drawbacks. The upper limit of the combustion reaction temperature is limited by the fuel type, making it difficult to overcome the phase transition energy barrier of high-melting-point oxides in local areas. If melting refractory components, the temperature of the entire molten pool needs to be raised to over 1600℃, leading to an exponential increase in energy consumption, while also exacerbating furnace lining erosion and compromising slag shape control. Summary of the Invention

[0004] The purpose of this invention is to provide a plasma-side-blown coupled melting furnace and its smelting method that can break through the phase transition energy barrier of high-melting-point oxides in a local area.

[0005] The plasma-side-blown coupled melting furnace provided by this invention includes a furnace body, partition walls, a melting zone, a reduction-sulfurization zone, a clarification and separation zone, a feeding device, a plasma torch, and side-blown tuyeres. A continuous molten pool is formed inside the furnace body. The partition walls within the furnace body physically divide the molten pool into the melting zone, the reduction-sulfurization zone, and the clarification and separation zone. The melting zone is used for initial melting of materials and heat transfer; the reduction-sulfurization zone is used for chemical reactions and metal separation; and the clarification and separation zone is used for melt clarification and phase separation. The feeding device includes a refractory material disposed at the top of the melting zone. The system includes a material feeding port and a conventional material feeding port. The refractory material feeding port is used to feed high-melting-point nickel-containing materials, while the conventional material feeding port is used to feed low-melting-point nickel-containing materials. A plasma torch is positioned above the melting zone and adjacent to the refractory material feeding port, forming a localized high-temperature zone below the refractory material drop point to overcome the phase transition energy barrier of the high-melting-point oxide. A side-blowing vent is located on the side wall of the melting zone and submerged below the molten pool surface. It is configured to blow gas into the molten pool to generate macroscopic circulation, dispersing the overheated melt generated in the localized high-temperature zone throughout the entire molten pool.

[0006] In one embodiment of the above-mentioned smelting furnace, the built-in partition wall is a water-cooled copper water jacket structure with embedded refractory material and a self-solidifying slag protective layer formed on the working surface.

[0007] In one embodiment of the above-mentioned smelting furnace, the number of refractory material feeding ports is at least one, and the number of conventional material feeding ports is at least one.

[0008] In one embodiment of the above-mentioned smelting furnace, the plasma torch is a transfer plasma torch, the power of which can be independently adjusted to generate a temperature exceeding 3000°C in the local high-temperature zone.

[0009] In one embodiment of the above-mentioned smelting furnace, air is blown in through the side-blowing vents, and the gas flow rate can be adjusted independently.

[0010] In one embodiment of the above-mentioned smelting furnace, a channel is provided below the partition wall for molten material to flow from the melting zone into the reduction and sulfidation zone.

[0011] A method for smelting using the above-mentioned smelting furnace includes the following steps:

[0012] S1. Nickel-containing solid waste is divided into refractory materials and conventional materials based on the refractory properties of the matrix. The refractory materials are materials whose matrix is ​​rich in high-melting-point oxides, and the conventional materials are materials with relatively low melting points.

[0013] S2. Refractory materials are fed into the melting zone through the refractory material feeding port, and conventional materials are fed into the melting zone through the conventional material feeding port;

[0014] S3. The plasma torch is activated to target and heat the refractory material to form a superheated liquid melt;

[0015] S4. Gas is blown into the molten pool through the side air vent to form a forced macroscopic circulation, which disperses the superheated liquid melt as a heat transfer medium and transfers heat to the conventional material through liquid-liquid contact, thereby accelerating its melting.

[0016] S5. The molten material flows into the reduction and sulfidation zone through the channel below the built-in partition wall, and a reducing agent and a sulfiding agent are added to react and generate a nickel matte phase;

[0017] S6. After the reaction, the melt flows into the clarification and separation zone, is allowed to stand and separate into layers, separating the matte from the slag and then discharged.

[0018] In step S3, the power of the plasma torch and the gas flow rate of the side blower in step S4 are independently adjustable process parameters to achieve decoupled control of the phase transformation melting process of refractory materials and the macroscopic thermochemical state of the molten pool.

[0019] The refractory material is selected from materials rich in... Lateritic nickel ore of sapropelic type, rich in Waste catalysts or rich in and One or more of the following stainless steel slags.

[0020] The conventional materials are limonite-type laterite nickel ore or electroplating sludge.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. The molten pool is physically divided into a melting zone and a reduction and sulfidation zone by an internal partition wall, and functional feeding ports for refractory materials and conventional materials are set at the top of the melting zone; this allows nickel-containing solid waste of different properties to be processed separately in the molten pool; it solves the compatibility problem of smelting with multiple sources of materials coexisting, and improves smelting efficiency and process stability.

[0023] 2. The plasma torch precisely targets the point where refractory materials fall, while the side-blowing system is immersed in the molten pool to drive macroscopic circulation. The plasma torch specializes in the phase change of high-melting-point materials, generating ultra-high temperatures in a very small area to avoid overheating of the entire molten pool. The side-blowing airflow rapidly disperses the generated superheated melt as a "liquid heat carrier" to the entire molten pool, utilizing the high efficiency of liquid-liquid heat transfer to significantly accelerate the melting of conventional materials and significantly reduce overall energy consumption. Attached Figure Description

[0024] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention. Detailed Implementation

[0025] The relevant technical solutions will now be clearly and completely described with reference to the accompanying drawings of the embodiments of the present invention. The described embodiments are only a part of the embodiments, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, the plasma-side-blown coupled melting furnace disclosed in this embodiment includes a furnace body 1, a partition wall 2, a melting zone 3, a reduction and sulfidation zone 4, a clarification and separation zone 5, a refractory material feeding port 6, a conventional material feeding port 7, a plasma torch 8, and a side-blown air outlet 9.

[0027] The interior of the single furnace body 1 forms a continuous molten pool for containing and processing nickel-containing materials. The furnace body is lined with refractory material to ensure structural integrity and thermal stability during high-temperature smelting.

[0028] Inside the molten pool, two built-in partitions 2 are set up, which physically divide the molten pool into three main areas: the melting zone 3, the reduction and sulfidation zone 4, and the clarification and separation zone 5.

[0029] The melting zone 3 is located on one side of the partition wall 2 and is specifically used for the initial melting of materials and heat transfer; the reduction and sulfidation zone 4 is located between the two partition walls and is used for subsequent chemical reactions and metal separation; the clarification and separation zone 5 is located on the other side of the partition wall to optimize material flow and phase separation processes.

[0030] Both partition walls 2 adopt a water-cooled copper water jacket structure with embedded refractory material, forming a self-solidifying slag protective layer on the working surface to enhance high temperature resistance and corrosion resistance.

[0031] The top of the melting zone 3 is provided with two refractory material feeding ports 6 and two conventional material feeding ports 7.

[0032] Feed port 6 for refractory materials is used to input high-melting-point materials, such as those rich in... The feed port 7 is for feeding materials with lower melting points, such as limonite-type lateritic nickel ore. The feed port position has been optimized to ensure that the material falls accurately into the designated area.

[0033] Multiple transfer-type plasma torches 8 are installed above the melting zone 3, with their nozzles facing the interior of the melting zone and adjacent to the refractory material feeding port 6. The nozzles of the plasma torches create a local high-temperature zone exceeding 3000°C below the point where the refractory material falls, which is used to perform the phase change melting of high-melting-point materials.

[0034] Multiple sets of side air vents 9 are installed on the side wall of the melting zone 3. The side air vents are submerged below the surface of the molten pool and are used to blow gas into the molten pool to generate macroscopic overall circulation and perform macroscopic homogenization and heat transfer tasks.

[0035] The purpose of this smelting pool is to achieve a highly efficient and low-energy-consumption smelting process, specifically designed for processing multi-source refractory-based nickel-containing materials. This is achieved through a functional decoupling and synergistic heat transfer mechanism: the plasma torch instantaneously generates ultra-high temperatures at the point where the refractory material falls, overcoming the phase transition energy barrier from solid to liquid and forming a small stream of superheated melt; simultaneously, gas is blown in through side ducts to create macroscopic circulation, rapidly dispersing the superheated melt as a liquid heat carrier throughout the pool, utilizing the high efficiency of liquid-liquid heat transfer to accelerate the melting of conventional materials. This zoned processing and heat transfer mechanism significantly reduces overall energy consumption and improves process stability and metal recovery rate.

[0036] This embodiment also discloses a method for smelting using the above-mentioned smelting pool, the specific steps of which are as follows:

[0037] S1. Based on the refractory properties of the matrix, nickel-containing solid waste is divided into two categories: refractory materials and conventional materials.

[0038] Refractory materials are materials whose matrix is ​​rich in high-melting-point oxides, selected from materials rich in... Lateritic nickel ore of sapropelic type, rich in Waste catalysts, or those rich in and The stainless steel slag is of medium quality; the conventional materials are those with relatively low melting points, such as limonite-type laterite nickel ore or electroplating sludge.

[0039] Refractory materials are fed into the melting zone through the refractory material feed port; conventional materials are fed into the melting zone through the conventional material feed port.

[0040] S2. Start the plasma torch to target and heat the refractory material introduced in step S1 to overcome the phase transition energy barrier from solid to liquid phase and form an overheated liquid melt.

[0041] S3. Gas is blown into the molten pool through the side air vents, and the gas forms a forced macroscopic circulation in the molten pool. The circulation uses the superheated liquid phase melt formed in step S2 as an efficient heat transfer medium to transfer heat to the conventional material through liquid-liquid contact, so that it melts quickly, thereby accelerating the melting process of the entire melting zone.

[0042] S4. The molten material homogenized in step S3 flows into the reduction and sulfidation zone through the channel below the partition wall; a reducing agent and a sulfiding agent are added to the reduction and sulfidation zone, and react at high temperature to generate the matte phase; after the reaction, the melt flows into the clarification and separation zone, is allowed to stand and separate into layers, and the matte is separated from the slag and discharged.

[0043] In step S2, the plasma torch power and the side-blowing gas and fuel flow rate in step S3 are two independently adjustable process parameters, thereby achieving decoupled control of the phase change melting process of refractory materials and the macroscopic thermochemical state of the molten pool.

[0044] By adjusting the plasma torch power, a core temperature of several thousand degrees Celsius is generated in a localized high-temperature zone to ensure that the high-melting-point oxide matrix is ​​rapidly liquefied.

[0045] The following sections will use multiple scenarios and comparative examples to illustrate in detail the specific application methods and technical advantages of this invention in processing multi-source nickel-containing materials with different ratios and types.

[0046] To scientifically and fairly evaluate the energy consumption levels of this invention and existing technologies, this invention proposes and adopts "comprehensive equivalent coal rate" as a unified metric. This metric converts all forms of energy input in the process, including directly consumed fossil fuels and indirectly consumed electricity, into standard coal equivalent.

[0047] In an embodiment of the present invention, the formula for calculating the comprehensive equivalent coal ratio is as follows:

[0048] Overall equivalent coal rate = direct coal rate + plasma power consumption equivalent coal rate;

[0049] in:

[0050] Direct coal ratio: refers to the ratio of the mass of pulverized coal (reducing agent, fuel) directly added into the furnace through side tuyeres, spray guns, etc., to the mass of the dry material being processed;

[0051] Plasma power consumption equivalent coal rate: refers to the ratio of the mass of standard coal equivalent to the electrical energy consumed by the plasma torch to the mass of the dry material processed;

[0052] Conversion standard: Based on the power generation efficiency of a typical coal-fired power plant, this invention adopts the common engineering calculation standard, which calculates 1 kWh of electricity as equivalent to 0.4 kg of standard coal.

[0053] Scenario 1: Handling extremely harsh working conditions dominated by refractory materials;

[0054] This invention treats high-proportion waste catalyst mixtures;

[0055] (1) Material preparation: Refractory materials (60% waste catalyst) are mixed with conventional materials (40% limonite), with a total processing capacity of 100 tons / hour.

[0056] (2) Smelting process:

[0057] Plasma torch: designed for melting 60 tons / hour of spent catalyst, with an average power output of 25,000 kW and a power consumption of 25,000 kWh / h.

[0058] Side-blowing system: Direct coal input is (100 tons × 5%) = 5 tons / hour.

[0059] Reduction sulfidation zone: The amount of reducing agent pulverized coal added is (100 tons × 10%) = 10 tons / hour.

[0060] The macroscopic temperature of the main molten pool is maintained at 1500℃.

[0061] (3) Energy consumption calculation and results:

[0062] Direct coal consumption: 5 + 10 = 15 tons / hour. Direct coal rate: 15%.

[0063] Plasma power consumption equivalent to coal consumption: 25000 kWh / h × 0.4 kg / kWh = 10000 kg / h = 10 tons / hour. Power consumption equivalent to coal rate: 10%.

[0064] Overall equivalent coal rate: 15% + 10% = 25%.

[0065] Nickel content in the slag: 0.19%. The process is running smoothly.

[0066] Comparative Example 1: A traditional oxygen-enriched side-blown furnace processing the same material;

[0067] (1) Material preparation: Same as scenario one.

[0068] (2) Smelting process: In order to forcibly raise the macroscopic temperature of the entire molten pool to above 1600℃ in order to melt 60% of the waste catalyst.

[0069] (3) Results:

[0070] Overall coal ratio: Unable to operate stably. To reach the required temperature, the direct coal ratio needs to exceed 30%, leading to deterioration of furnace conditions and forced shutdown.

[0071] Scenario 2: Common working conditions where the main materials are conventional but contaminated by refractory materials;

[0072] This invention processes laterite nickel ore containing a small amount of stainless steel slag;

[0073] (1) Material preparation: Conventional materials (90% saprophytic ore) are mixed with refractory materials (10% stainless steel slag), with a total processing capacity of 100 tons / hour.

[0074] (2) Smelting process:

[0075] Plasma torch: designed for precise melting of 10 tons / hour of stainless steel slag, with an average power of 5000 kW and a power consumption of 5000 kWh / h.

[0076] Side-blowing system: Direct coal input is (100 tons × 12%) = 12 tons / hour.

[0077] Reduction sulfidation zone: The amount of reducing agent pulverized coal added is (100 tons × 10%) = 10 tons / hour.

[0078] The macroscopic temperature of the main molten pool is maintained at 1500℃.

[0079] (3) Energy consumption calculation and results:

[0080] Direct coal consumption: 12 + 10 = 22 tons / hour. Direct coal rate: 22%.

[0081] Plasma power consumption equivalent to coal consumption: 5000 kWh / h × 0.4 kg / kWh = 2000 kg / h = 2 tons / hour. Power consumption equivalent to coal rate: 2%.

[0082] Overall equivalent coal rate: 22% + 2% = 24%.

[0083] Nickel content in the slag: 0.20%.

[0084] Comparative Example 2: A traditional oxygen-enriched side-blown furnace processing the same material;

[0085] (1) Material preparation: Same as scenario two.

[0086] (2) Smelting process: In order to ensure that 10% of the stainless steel slag does not clump, the macroscopic temperature of the entire molten pool was forced to be increased from 1500℃ to 1580℃.

[0087] (3) Results:

[0088] Overall coal ratio (direct coal ratio): 27%. In order to effectively raise the temperature of the entire molten pool to 80°C, a large amount of additional pulverized coal is required.

[0089] Nickel content in the slag: 0.25%.

[0090] Scenario 3: Advanced working conditions for synergistic smelting using the chemical properties of different materials;

[0091] This invention enables high-performance collaborative processing. Stainless steel slag and high Electroplating sludge;

[0092] (1) Material preparation: Refractory materials (40% stainless steel slag) are mixed with conventional materials (60% electroplating sludge), with a total processing capacity of 100 tons / hour.

[0093] (2) Smelting process:

[0094] Plasma torch: designed for efficient melting of 40 tons / hour of stainless steel slag, with an average power of 15,000 kW and a power consumption of 15,000 kWh / h.

[0095] Side-blown system: Due to synergistic effects, only a small amount of coal is needed for stirring and maintaining the atmosphere, with a direct coal ratio (melting zone) of 4%.

[0096] Reduction sulfidation zone: The amount of reducing agent pulverized coal added is 10%.

[0097] The macroscopic temperature of the main molten pool was maintained at 1450℃.

[0098] (3) Energy consumption calculation and results:

[0099] Direct coal consumption: 4 + 10 = 14 tons / hour. Direct coal rate: 14%.

[0100] Plasma power consumption equivalent to coal consumption: 15000 kWh / h × 0.4 kg / kWh = 6000 kg / h = 6 tons / hour. Power consumption equivalent to coal rate: 6%.

[0101] Overall equivalent coal rate: 14% + 6% = 20%.

[0102] Nickel content in the slag: 0.16%.

[0103] Comparative Example 3: A traditional oxygen-enriched side-blown furnace processing the same material;

[0104] (1) Material preparation: Same as scenario three.

[0105] (2) Smelting process: The mixture was added evenly, but the melting was slow and the synergistic effect was not achieved.

[0106] (3) Results:

[0107] Overall coal ratio (direct coal ratio): 23%.

[0108] Nickel content in the slag: 0.35%.

[0109] The following is a summary table of results and conclusions from multiple scenarios:

[0110]

[0111] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A plasma-side-blown coupled melting furnace, characterized in that: Includes furnace body, partition walls, melting zone, reduction and sulfidation zone, clarification and separation zone, feeding device, plasma torch and side blowing vents; A continuous molten pool is formed inside the furnace body; the furnace body has internal partition walls that physically divide the molten pool into a melting zone, a reduction and sulfidation zone, and a clarification and separation zone; the melting zone is used for the initial melting of materials and heat transfer, the reduction and sulfidation zone is used for chemical reactions and metal separation, and the clarification and separation zone is used for melt clarification and phase separation. The feeding device includes a refractory material feeding port and a conventional material feeding port located at the top of the melting zone. The refractory material feeding port is used to feed high-melting-point nickel-containing materials, and the conventional material feeding port is used to feed low-melting-point nickel-containing materials. The plasma torch is positioned above the melting zone and adjacent to the refractory material feeding port, forming a local high-temperature zone below the refractory material falling point to overcome the phase transition energy barrier of the high-melting-point oxide. The side-blowing air outlet is located on the side wall of the melting zone and is submerged below the surface of the molten pool. It is configured to blow gas into the molten pool to generate macroscopic circulation, dispersing the overheated melt generated in the local high-temperature zone to the entire molten pool.

2. The plasma-side-blown coupled melting furnace as described in claim 1, characterized in that: The built-in partition wall is a water-cooled copper water jacket structure with embedded refractory material and a self-solidifying slag protective layer formed on the working surface.

3. The plasma-side-blown coupled melting furnace as described in claim 1, characterized in that: The number of feed ports for refractory materials is at least one, and the number of feed ports for conventional materials is at least one.

4. The plasma-side-blown coupled melting furnace as described in claim 1, characterized in that: The plasma torch is a transfer-type plasma torch, whose power can be independently adjusted to generate temperatures exceeding 3000°C in the local high-temperature zone.

5. The plasma-side-blown coupled melting furnace as described in claim 1, characterized in that: The side air vent blows in air, and the gas flow rate can be adjusted independently.

6. The plasma-side-blown coupled melting furnace as described in claim 1, characterized in that: A channel is provided below the partition wall for molten material to flow from the melting zone into the reduction and vulcanization zone.

7. A method for smelting using a smelting furnace as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Nickel-containing solid waste is divided into refractory materials and conventional materials based on the refractory properties of the matrix. The refractory materials are materials whose matrix is ​​rich in high-melting-point oxides, and the conventional materials are materials with relatively low melting points. S2. Refractory materials are fed into the melting zone through the refractory material feeding port, and conventional materials are fed into the melting zone through the conventional material feeding port; S3. The plasma torch is activated to target and heat the refractory material to form a superheated liquid melt; S4. Gas is blown into the molten pool through the side air vent to form a forced macroscopic circulation, which disperses the superheated liquid melt as a heat transfer medium and transfers heat to the conventional material through liquid-liquid contact, thereby accelerating its melting. S5. The molten material flows into the reduction and sulfidation zone through the channel below the built-in partition wall, and a reducing agent and a sulfiding agent are added to react and generate a nickel matte phase; S6. After the reaction, the melt flows into the clarification and separation zone, is allowed to stand and separate into layers, separating the matte from the slag and then discharged.

8. The method as described in claim 7, characterized in that: In step S3, the power of the plasma torch and the gas flow rate of the side blower in step S4 are independently adjustable process parameters to achieve decoupled control of the phase transformation melting process of refractory materials and the macroscopic thermochemical state of the molten pool.

9. The method as described in claim 7, characterized in that: The refractory material is selected from materials rich in... Lateritic nickel ore of sapropelic type, rich in Waste catalysts or rich in and One or more of the following stainless steel slags.

10. The method as described in claim 7, characterized in that: The conventional materials are limonite-type laterite nickel ore or electroplating sludge.

Images