A double hearth alternate mineral suspension smelting system

Abstract

This invention belongs to the field of mineral powder melting technology, specifically disclosing a dual-chamber alternating mineral suspension smelting system. The invention includes a melting furnace, a heat storage body, a three-way valve, a combustion fan, and an exhaust fan. The melting furnace comprises two furnace chambers arranged side-by-side and connected to each other via a bottom molten pool. Heat storage bodies are respectively installed at the airflow inlets of the two furnace chambers. The heat storage bodies are connected to the combustion fan and the exhaust fan respectively via corresponding three-way valves. When one furnace chamber is the melting chamber, the other is the heat storage chamber. The melting chamber is connected to the combustion fan, and the heat storage chamber is connected to the exhaust fan. The material melts in the melting chamber, and high-temperature flue gas is discharged from the top of the heat storage chamber, heating the heat storage body. The heated heat storage body can preheat the combustion fan. The technical solution of this invention, through the alternating roles of the two chambers, suspends and melts the material, which can significantly improve heat exchange efficiency and melt uniformity. Simultaneously, the recovery and utilization of high-temperature flue gas also helps to further reduce energy consumption.

Description

Technical Field

[0001] This invention relates to the field of mineral powder melting technology, specifically to a dual-chamber alternating mineral suspension smelting system. Background Technology

[0002] In the inorganic non-metallic materials and metallurgical industries, the high-temperature melting of mineral raw materials to achieve component homogenization or phase transformation is a key step shared by many core processes. Typical scenarios include: melt-drawing production of basalt fiber and mineral wool fiber, melt-reduction ironmaking of iron ore powder, smelting of copper concentrate, and calcination and melting of bauxite. Although these processes belong to different downstream industries, they face common underlying technological challenges in the thermal treatment stage.

[0003] Take basalt fiber as an example. Currently, basalt fiber is mainly produced using flame furnaces and combined fire-electric furnaces. Although the technology is mature and the product quality is stable, its industrialization faces significant bottlenecks. This is because basalt raw materials typically contain more than 10% Fe. 3+ Iron ions cause the molten basalt to be dark brown and have poor light transmittance, thus hindering heat transfer through radiation. Secondly, the very high viscosity of basalt melt results in minimal internal convection, leading to poor convective heat transfer. Furthermore, the melt itself has poor thermal conductivity, with a low coefficient of only about 2 W / (m·K), resulting in extremely weak conductive heat transfer. These characteristics of basalt raw materials inevitably lead to the following technical drawbacks when using flame furnaces or combined thermal-electric furnaces for production:

[0004] 1. High energy consumption in production

[0005] The heat transfer bottleneck of existing flame-fired tank kilns stems from inherent defects in their energy transfer path: after the high-temperature flame transfers heat to the surface of the basalt melt through radiation and convection, the heating of the deeper melt relies entirely on heat conduction, resulting in an effective heat exchange depth of less than 200 mm in the molten pool. Of the heat generated by fuel combustion, approximately 55-65% is directly emitted through the chimney as high-temperature flue gas at 400-600°C. Even with the addition of shell-and-tube flue gas heat exchangers for waste heat recovery, the actual thermal energy utilization rate is still less than 35%. This inherent deficiency in energy transfer efficiency results in a comprehensive energy consumption of 3-4 GJ / t per unit product for flame-fired tank kilns, which is 40-50% higher than that of similar glass fiber products. Fuel costs account for more than 40% of the total production cost, becoming a key factor restricting production cost control.

[0006] 2. Low production efficiency

[0007] In existing pool furnace production processes, the heat transfer efficiency from the flame to the basalt melt is very low. The propagation of heat into the molten pool requires a very slow heat conduction process, resulting in very low output per pool furnace, with the annual capacity of a single unit generally below 5,000 tons. Simultaneously, the direct impact of the gas jet on the material surface at a certain speed creates an upward rebound velocity. This velocity can easily induce some gas to escape from the top of the jet hood, further impacting production efficiency.

[0008] 3. Poor melt quality

[0009] Because the heat conduction path in the furnace pool is long (depth 150~180mm), there is a temperature gradient of 100~200℃ from top to bottom in the melt, which causes fluctuations in the temperature and viscosity of the discharged melt, directly affecting the online fiber breakage rate of basalt fiber drawing (current level about 5~15 times per machine per day) and the uniformity of the strength of the finished fiber (coefficient of variation CV is usually >8%).

[0010] 4. Long material replacement cycle

[0011] The large melt volume (several tons to tens of tons) in the tank furnace means that it takes several hours to several days to completely replace the melt composition when changing the raw material formula or adjusting the process, resulting in poor production flexibility.

[0012] The aforementioned defects result in basalt fiber production being significantly inferior to the mature, large-scale production system of traditional glass fiber, particularly in terms of cost control and capacity efficiency. This severely weakens its competitiveness in the composite materials market and has become a key technological barrier restricting industrial breakthroughs. Summary of the Invention

[0013] The main objective of this invention is to provide a dual-chamber alternating mineral suspension smelting system to solve the problems of high energy consumption, low production efficiency, and insufficient melt uniformity in existing mineral melting production technologies.

[0014] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0015] A dual-chamber alternating mineral suspension smelting system includes a melting furnace, a heat storage medium, three-way valves, a combustion air blower, and an exhaust fan. The melting furnace includes a molten pool and two furnace chambers arranged side-by-side above the molten pool and connected to each other via the molten pool. Each of the two furnace chambers has an airflow inlet at its top, and a heat storage medium is correspondingly located at each airflow inlet. The number of three-way valves corresponds to the number of heat storage mediums, and each valve's three ports connect to the corresponding heat storage medium, the outlet of the combustion air blower, and the inlet of the exhaust fan, respectively. When one furnace chamber is the melting chamber, the other furnace chamber is the heat storage chamber; the melting chamber is connected to the combustion air blower, and the heat storage chamber is connected to the exhaust fan. The upper part of each furnace chamber has, from top to bottom, a material fluidization inlet, a fluidizing air inlet, and a fuel inlet. The bottom of the molten pool has a molten material outlet.

[0016] This invention employs a dual-chamber alternating suspension melting scheme, with the melting chamber and regenerator periodically exchanging roles. Material enters the furnace from the upper part of the melting chamber and is in a suspended fluidized state under the influence of upward fluidizing air and high-temperature flue gas, as well as downward combustion air. The high-temperature flue gas melts the powder, and the resulting droplets continuously collide, adhere, and grow, moving downwards with the high-temperature flue gas. When the gas-liquid mixture passes through the molten pool, its direction of movement changes from downwards to the opposite side of the furnace. The molten droplets, due to their greater inertia, fall into the molten pool, while the high-temperature flue gas enters the opposite side of the furnace, thus achieving gas-liquid separation. When the high-temperature flue gas passes through the regenerator at the top of the regenerator, it heats the regenerator. Therefore, during the next cycle of dual-chamber role exchange, the heated regenerator heats the incoming combustion air, promoting combustion and improving energy efficiency. By setting the dual-chamber role exchange periodically (reversal cycle 30-60s, preferably 40s), long-term melting operations and continuous waste heat recovery are possible, which is beneficial for high efficiency, energy saving, and long-term stable system operation. Meanwhile, compared to the traditional pool furnace method, suspension melting has a larger specific surface area of ​​powder, which allows for full contact with high-temperature flue gas, thus improving production efficiency and reducing energy consumption. Moreover, the suspended powder particles are heated uniformly, avoiding temperature gradients and component stratification in the molten material within the molten pool, resulting in good melt homogeneity.

[0017] In this invention, the switching between the melting chamber and the regenerator chamber is achieved through the coordinated switching of two three-way valves. Specifically, when this side of the furnace is the melting chamber, two valve ports of this side's three-way valve are connected to the regenerator and the exhaust fan outlet on this side, respectively, while the other valve port is disconnected from the exhaust fan inlet. Conversely, two valve ports of the opposite side's three-way valve are connected to the opposite side's regenerator and the exhaust fan inlet, respectively, while the other valve port is disconnected from the exhaust fan outlet. The combustion air enters the melting chamber through the combustion fan via the three-way valve and the regenerator on this side, mixes with fuel, and combusts to form high-temperature flue gas. This flue gas then passes through the regenerator, the opposite regenerator, and the opposite three-way valve before being discharged from the exhaust fan. Specifically, the two three-way valves are linked via a communication connection (such as Bluetooth). The three-way valves can be T-type three-way ball valves.

[0018] The heat storage medium is used to absorb heat from the high-temperature flue gas to raise its temperature when it flows through, and to release heat to preheat the low-temperature combustion air when it flows through. Specifically, the heat storage medium can be a honeycomb ceramic heat storage medium made of cordierite (long-term operating temperature ≤1300℃) or mullite (long-term operating temperature ≤1600℃), with a pore density of 200~400 pores / square inch (CPSI) and a specific surface area of ​​800~1200 m². 2 / m 3 The porosity is 50%~70%, and the total height is 800~2000mm. In a single cycle, the heat storage body can rise from about 130℃ to 900~1000℃.

[0019] In this invention, the raw materials need to be crushed before melting, typically to a particle size of less than 1 mm, thereby further improving the melting efficiency of the powder. The powder is injected into the furnace obliquely downward through the material fluidization inlet. Fluidizing air and fuel (usually natural gas) are injected into the furnace from below the powder, and combustion air is injected into the furnace from the top. The mixed flow field formed by these three airflows fully disperses the powder and melts it in a suspended state, achieving efficient melting and energy saving. The material fluidization inlet and the fluidizing air inlet are located near the furnace top, and the mainstream direction of the mixing flow field is downward. This utilizes the local vortex effect generated by the stepped flow field to further enhance the mixing effect and help transport the gas-liquid mixture to the opposite side of the furnace.

[0020] Preferably, there are multiple material fluidization inlets, multiple fluidizing air inlets, and multiple fuel inlets, which are uniformly arranged circumferentially along the furnace. The injection axes of the fluidizing air inlets and the fuel inlets are both inclined upwards relative to the horizontal plane.

[0021] Specifically, the number of material fluidization inlets, fluidizing air inlets, and fuel inlets is usually the same, and they correspond one-to-one with each other. The corresponding material fluidization inlets, fluidizing air inlets, and fuel inlets are all on the same vertical line. The injection axes of both the fluidizing air inlet and the fuel inlet are inclined upwards, allowing the high-temperature flue gas generated by the fluidizing air and fuel combustion to collide violently with the downward-facing combustion air, thereby dispersing the powder and ensuring uniform heating. Furthermore, the injection angles (angles with the vertical direction) of the fluidizing air and fuel are both 30°~60°, the fuel injection velocity is 20~50 m / s, and the combustion air outlet velocity is 10~25 m / s.

[0022] Preferably, the upper part of the furnace is provided with a radially expanding, annular feeding chamber. Multiple lifting plates are evenly arranged circumferentially on the sidewalls of the feeding chamber. The material fluidization inlet is located at the upper end of the lifting plate, and the fluidizing air inlet is located at the lower end of the lifting plate. The angle between the lifting plate and the horizontal plane is 30° to 60°.

[0023] The feeding chamber is formed by expanding the furnace diameter outwards, which avoids the lifting plates occupying the melting space inside the furnace and affecting the flow field, thus facilitating the dispersion and melting of the powder. Specifically, the material fluidization inlet is located at the top of the feeding chamber, and the fluidizing air inlet is located at the bottom. The powder enters the melting chamber from the material fluidization inlet, first reaching the lifting plates, which change the direction of the originally streamed material flow, forming a material curtain with a certain arc, thereby uniformly dispersing the powder. Specifically, the number of lifting plates is usually consistent with the number of material fluidization inlets, and they correspond one-to-one. Typically, 8 to 24 lifting plates are arranged around the circumference of the furnace, all at the same horizontal height, and the lifting plates are set at an inclination of 30° to 60° (relative to the horizontal plane), preferably 45°. The lifting plates can adjust the speed, direction, and dispersion of the powder falling above the fluidizing air inlet, thereby ensuring that the powder is fully melted. The lifting plates can be made of heat-resistant cast steel ZG40Cr25Ni20 or reaction-sintered silicon carbide ceramic. Furthermore, the fluidizing air inlet is a flat rectangular nozzle, and even further, the flat rectangular nozzle is the same width as the lifting plate, thereby further promoting powder dispersion.

[0024] Preferably, the bottom surface of the molten pool includes a central bottom surface located in the middle, and an annular bottom surface surrounding the central bottom surface. The horizontal projection of the furnace is located within the central bottom surface. The central bottom surface is higher than its surrounding area in the middle, and gradually decreases in height from the middle to the surrounding area. The annular bottom surface is horizontally positioned. The molten material outlets are located on the annular bottom surface, and a plurality of the molten material outlets are evenly arranged along the contour of the annular bottom surface.

[0025] This design allows the molten material to first drip onto the central bottom surface and then slide down to the molten material outlet located on the annular bottom surface. This facilitates the dispersion of the molten droplets to each molten material outlet, making it easier for the melt to flow out for downstream processing.

[0026] Preferably, the horizontal projection of the central bottom surface includes a first circular portion and a second circular portion with equal diameters located at both ends, and a connecting segment connecting the first and second circular portions with a width smaller than the diameter of the circular portions. The first and second circular portions are respectively directly opposite the two furnace chambers above.

[0027] Specifically, the horizontal projection of the central bottom surface is dumbbell-shaped, with the circular parts at both ends corresponding to the two furnace chambers. Regardless of which furnace chamber is switched to the melting chamber, the molten droplets can slide down along the central bottom surface to the outer annular bottom surface and be discharged.

[0028] Preferably, a molten pool weir is provided on the central bottom surface, arranged along the contour of the central bottom surface. The horizontal projections of both furnace chambers are located inside the molten pool weir. Multiple molten material channels are formed at the bottom of the molten pool weir.

[0029] Specifically, the molten material channels are formed through a through-wall gap at the bottom of the molten pool cofferdam, allowing the melt to flow from the inside to the outside of the cofferdam. Furthermore, the number of molten material channels and molten material outlets are the same, and they correspond one-to-one.

[0030] Specifically, the molten droplets first fall into the inner side of the dam, then enter the outer side of the dam through the molten material channel at the bottom, and finally exit through the molten material outlet. This design is because some incompletely molten fine powder may exist on the surface of the melt. If the melt is taken from the surface, this fine powder will directly enter the downstream processing stage (such as fiber drawing), affecting the quality of the final product (such as fiber breakage). However, by taking the melt from the bottom, the incompletely molten powder will further melt as it descends in the molten pool, resulting in better quality uniformity with the surrounding melt and improving the quality of downstream processing.

[0031] Preferably, the bottom of the molten pool is provided with a plurality of funnel-shaped discharge channels, each of which is evenly arranged along the contour of the central bottom surface on the annular bottom surface. The larger end of the discharge channel is connected to the molten pool, and the smaller end of the discharge channel forms the outlet of the molten material.

[0032] The funnel-shaped discharge channels facilitate the accumulation and outflow of melt, preventing melt residue from remaining in the molten pool. The uniform arrangement of each discharge channel along the contour of the central bottom surface of the ring ensures uniform discharge of molten material from each outlet, which is beneficial for downstream processing.

[0033] Preferably, an iron molten metal collection tank is provided between the central bottom surface and the annular bottom surface, and the two sides of the opening of the iron molten metal collection tank are respectively connected to the central bottom surface and the annular bottom surface. The bottom of the iron molten metal collection tank has multiple iron discharge ports, and each iron discharge port is evenly distributed along the contour of the central bottom surface.

[0034] This embodiment can be used to simultaneously recover iron during the smelting of iron-containing minerals. Taking basalt as an example, which contains approximately 10%~15% Fe2O3 / FeO, during the melting process, iron oxides are partially reduced to metallic iron (reduction rate 20%~40%) at high temperatures above 1500℃ and under a localized CO reducing atmosphere. The density of the molten iron is approximately 7.0 g / cm³. 3 It is much larger than that of basalt melt (~2.6 g / cm³). 3 Because the molten iron collection tank is located at the lowest point of the central bottom surface, the molten iron, under the influence of gravity, slides down the central bottom surface and settles into the collection tank. It is then periodically discharged through the iron discharge port and cast into iron ingots, thus achieving the separation and recovery of iron. This process requires no additional reducing agent and has low operating costs. Furthermore, the depth of the collection tank is typically 50-150 mm. It should be noted that a collection tank is not required during iron ore smelting.

[0035] Furthermore, to enhance the iron collection effect, a reducing agent injection port can be provided at the top of the molten pool. These ports are evenly distributed around the circumference of the molten pool, with their horizontal projections located within the central bottom surface. Alternatively, a graphite electrode pair can be installed on the central bottom surface. Injecting a reducing agent into the furnace enhances the iron separation effect, or electrolyzing the melt using the graphite electrode pair further promotes iron reduction.

[0036] Specifically, by setting up reducing agent injection inlets (usually 1-4) at the top of the molten pool and injecting reducing agents such as pulverized coal or natural gas, Fe2O3 / FeO can be reduced to metallic iron, increasing the reduction rate to 80%-95% and significantly improving iron recovery. It is important to note that the amount of reducing agent used must be controlled to avoid over-reduction of SiO2 and Al2O3.

[0037] Specifically, graphite electrode pairs (DC 3~6V, 0.5~2A / cm) 2 ), through electrolysis to remove Fe 2+ / Fe 3+ The iron is reduced to metallic iron at the cathode, with a reduction rate of >95% and high product purity.

[0038] The above scheme has the following advantages when combined with fiber production: (1) After the molten iron is discharged, the iron content of the melt is reduced to 2%~5%, and the light transmittance is improved. (2) Based on an annual production of 10,000 tons of fiber, about 1,000 tons of iron can be recovered per year, creating additional income.

[0039] Furthermore, a secondary heating device can be installed above the annular bottom surface, with the secondary heating device evenly distributed along the circumference of the molten pool. The secondary heating device can be one of an auxiliary burner, a heating resistor, or a medium-frequency induction coil. The secondary heating device is used to heat the surface of the melt, maintaining a uniform surface temperature (gradient <30℃), promoting the upward expulsion of bubbles, and reducing the wire breakage rate. Specifically, the secondary heating device is typically positioned 300-800 mm above the free surface of the melt, and its heat compensation accounts for 5%-15% of the total heat. The auxiliary burner can be a small natural gas burner. The heating resistor can be a MoSi2 or SiC heating element with a power density of 10-50 kW / m³. 2 The intermediate frequency induction coil is heated by electromagnetic induction. These three components can also be combined for synergistic effects.

[0040] Preferably, the system further includes a downstream processing device. The downstream processing device is located below the molten material outlet. The downstream processing device is one of a forming device, a reduction furnace, a converter, an anode furnace, or an electrolytic cell.

[0041] This invention can be used in mineral smelting for both fiber and non-fiber production. When the downstream process is basalt fiber production, the downstream processing unit is a drawing machine. When the downstream process is iron ore reduction ironmaking, the downstream processing unit is a reduction furnace. When the downstream process is copper smelting, the downstream processing unit is a converter or anode furnace. When the downstream process is bauxite smelting, the downstream processing unit is an electrolytic cell. Of course, the downstream processing unit can also be a casting / forming device used in other mineral smelting processes.

[0042] Preferably, the downstream processing device is a wire drawing device. A stencil is provided at the outlet of the molten material. The wire drawing device is located below the stencil.

[0043] The fiber drawing device is one embodiment of the downstream processing unit used to produce basalt fibers. It is prior art and will not be described in detail here. The spinneret is a well-known spinneret for drawing basalt (or glass) fibers (with an aperture typically of 0.6~1.0mm ± 0.02mm), usually made of platinum-rhodium alloy. It has several discharge holes at the bottom through which the high-temperature molten metal flows into the fiber drawing device for stretching and forming. Those skilled in the art can select spinnerets with different apertures and numbers of holes according to the diameter of the target fiber and the required production volume.

[0044] Taking basalt fiber production as an example, the specific production process of the system is as follows: At-temperature air supplied by the combustion blower is heated to approximately 900℃ or higher by the heat storage body at the top of the melting chamber, and then injected into the melting chamber from the bottom of the heat storage body. Powdered basalt raw materials (particle size generally required to be <1mm) are fed into the furnace through the material fluidization inlet. Under the action of the lifting plates and fluidizing air, the powder is evenly dispersed in the furnace. Because the fluidization inlet is located at the root of the furnace top, the hot air stream ejected from the heat storage body forms a negative pressure vortex at the root due to the characteristics of the stepped flow field, drawing the powdered material into the mainstream of the hot air stream, further enhancing the mixing effect between the powder and the hot air. Fuel is injected obliquely upwards into the furnace, igniting upon contact with the downward-flowing combustion hot air to form a stable combustion flame. As the high-temperature flue gas generated by combustion carries the powder downwards, intense heat exchange occurs between the gas and solid components. Due to the large specific surface area of ​​the powder, the contact area between the material per unit mass and the high-temperature flue gas is large. Simultaneously, the strong turbulence between the material and the airflow results in a high heat transfer coefficient. Therefore, the powder is rapidly heated to above its melting temperature (approximately 1500℃) during its movement, forming molten basalt droplets. This process typically completes within seconds. The mixture of hot flue gas and droplets moves downwards to the bottom of the furnace. Due to a change in the direction of movement and a decrease in airflow velocity, the molten basalt droplets and the high-temperature flue gas separate. The molten droplets fall into the bottom molten pool, while the flue gas exits from the other side of the regenerator. The molten droplets accumulate in the bottom molten pool and flow from the molten material channel at the bottom of the pool's weir into the funnel-shaped discharge channel, eventually flowing out from the bottom of the perforated plate to form the initial filament. During this process, the reduced molten iron slides down the central bottom surface under gravity and settles into the molten iron collection tank, where it is periodically discharged. The initial filament is then drawn into basalt fibers by the lower drawing machine, forming continuously produced basalt fibers. The separated high-temperature flue gas passes through the regenerator at the top of the other furnace chamber (i.e., the regenerator), where its temperature drops to approximately 130°C. It then passes through a three-way valve and is discharged by the exhaust fan. After one cycle (approximately 40 seconds), the combustion air is switched from the original combustion chamber to the original regenerator chamber via the coordination of the two three-way valves at the furnace top, and the flue gas is switched from the original regenerator chamber to the original combustion chamber for discharge. This periodic switching between the two furnace chambers enables continuous production.

[0045] Of course, when processing other minerals (such as iron ore), the operating parameters and downstream processing equipment need to be adjusted accordingly based on the material's density and melting point.

[0046] Specifically, the melting process consists of four stages:

[0047] 1. Preheating stage of the heat storage body – In the previous cycle, the furnace on this side operated as a heat storage chamber. High-temperature flue gas (1100~1300℃) from the opposite side passed through the heat storage body at the top of the furnace on this side from bottom to top. After the heat was transferred to the heat storage body, the temperature dropped to about 130℃ and was discharged. The heat storage body on this side was heated to 900~1000℃.

[0048] 2. Combustion-Melting Stage – During this cycle, the furnace on this side switches to the molten chamber. At ambient temperature, combustion air is heated to 850-1050℃ through a preheated regenerator above the furnace and then injected into the furnace at high speed (10-25 m / s). Powdered basalt material is fed into the furnace evenly through the material fluidization inlet and by the lifting plates and fluidizing air. Because the material fluidization inlet is located at the root of the furnace top, the stepped flow field effect generates a low-pressure reflux vortex zone, automatically drawing the powder into the main hot air flow zone for rapid and uniform mixing. Fuel is injected at an upward angle (30°-60° to vertical) (20-50 m / s), forming a counter-current diffusion combustion flame with the downward hot air in the upper part of the furnace. A ring-shaped reflux zone (approximately 0.3-0.5 times the furnace diameter in length) is generated at the root, entraining high-temperature flue gas and powder, extending the residence time. The maximum temperature in the combustion zone can reach 1600-1800℃. The powder undergoes three heating stages: hot air mixing and preheating stage (~0.5m, preheated to 600~800℃), flame zone rapid melting stage (~1~2m, completely melted within 0.5~2s), and droplet growth stage (~2~4m, colliding and merging to a diameter of 1~3mm).

[0049] 3. Gas-liquid separation stage – After the mixture of hot flue gas and liquid droplets reaches the bottom of the furnace, the flow direction is forced to change from downward to upward towards the opposite side of the furnace. Due to its high density and inertia (St>1), the liquid droplets cannot turn quickly and fall into the bottom molten pool under the action of inertia, while the flue gas (density about 0.25kg / m3, low inertia) smoothly turns and enters the opposite side of the regenerator.

[0050] 4. Cyclic Switching and Continuous Operation – After a cycle of 30-60 seconds (preferably 40 seconds), the two three-way valves on the furnace top switch in tandem (<2 seconds), switching the original combustion chamber to the regenerator chamber and vice versa. At the moment of switching, the high-temperature flue gas and the heat stored in the refractory material (~1500℃) are sufficient to maintain the melting temperature >1350℃, ensuring uninterrupted process and continuous production through alternating switching between the two sides.

[0051] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0052] 1. In this invention, the powder material and high-temperature flue gas directly contact each other for heat exchange in a turbulent suspended state, significantly improving the heat transfer coefficient, which is beneficial for improving energy utilization efficiency and reducing energy consumption. Simultaneously, the powdered material has a large specific surface area (in d...). 50 Based on a thickness of 150μm, approximately 14m 2The melting process can be completed within seconds, significantly increasing the annual capacity of a single unit and greatly improving production efficiency. Furthermore, in the suspended state, each powder particle is heated and melted almost simultaneously, eliminating the temperature gradient and component stratification of the molten material found in tank furnaces, resulting in excellent melt uniformity. In addition, the amount of material remaining in the melting furnace is much less than in tank furnaces, reducing the time required to change raw material formulations or adjust processes, thus significantly improving production flexibility.

[0053] 2. This invention employs a dual-chamber alternating, suspension melting scheme. The periodic exchange of roles between the melting chamber and the regenerator chamber enables continuous production and ongoing waste heat recovery, which is beneficial for high efficiency, energy saving, and long-term stable system operation. In the melting chamber, the material is thoroughly dispersed by upward-flowing fluidizing air and high-temperature flue gas, as well as downward-flowing combustion air, and undergoes suspension melting, thereby further improving melting efficiency. Molten droplets move towards the regenerator chamber with the high-temperature flue gas. During this process, the molten droplets continuously collide, adhere, and grow. Due to the parallel arrangement of the two chambers, the gas-liquid mixture changes its direction of movement from downward to towards the opposite furnace chamber when passing through the molten pool. The molten droplets, due to their greater inertia, fall back into the molten pool, while the high-temperature flue gas enters the opposite furnace chamber, thus achieving gas-liquid separation. The separated high-temperature flue gas can heat the regenerator at the top of the regenerator chamber. Thus, in the next working cycle, when the roles of the two chambers are exchanged, the heated regenerator can preheat the combustion air, thereby promoting combustion and improving energy utilization efficiency.

[0054] 3. In this invention, an iron molten collection tank for separating and recovering iron elements is provided between the central bottom surface and the annular bottom surface of the molten pool. During the melting process of the powder, iron oxides can be partially reduced to metallic iron under high temperature above 1500℃ and local CO reducing atmosphere, so that they naturally settle into the iron molten collection tank and are discharged from the iron discharge port at the bottom of the iron molten collection tank. While realizing the collection of iron elements, it is beneficial to improve the quality of the melt. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of the previous working cycle of the dual-chamber alternating mineral suspension smelting system of the present invention.

[0056] Figure 2 This is a schematic diagram of the structure of the second working cycle of the dual-chamber alternating mineral suspension smelting system of the present invention.

[0057] Figure 3 This is a cross-sectional view of the dual-chamber alternating mineral suspension smelting system of the present invention.

[0058] Figure 4 This is a schematic diagram of the feeding structure of the dual-chamber alternating mineral suspension smelting system of the present invention.

[0059] Figure label:

[0060] 1: Furnace chamber; 2: Heat storage body; 3: Material fluidization inlet; 4: Fuel inlet; 5: Molten pool; 6: Central bottom surface; 7: Discharge channel; 8: Downstream processing device; 9: Molten pool dike; 10: Molten material channel; 11: Three-way valve; 12: Combustion fan; 13: Exhaust fan; 14: Lifting plate; 15: Fluidizing air inlet; 16: Annular bottom surface; 17: Molten iron collection tank; 18: Iron discharge port; 19: Feed chamber. Detailed Implementation

[0061] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0062] Please refer to Figures 1 to 4 A dual-chamber alternating mineral suspension smelting system includes a melting furnace, a heat storage body 2, a three-way valve 11, a combustion air blower 12, and an exhaust fan 13. The melting furnace includes a molten pool 5 and two furnace chambers 1 arranged side-by-side above the molten pool 5 and connected to each other through the molten pool 5. Each of the two furnace chambers 1 has an airflow inlet at its top, and a heat storage body 2 is correspondingly located at each airflow inlet. The number of three-way valves 11 corresponds to the number of heat storage bodies 2. The three ports of each three-way valve 11 can respectively connect to the corresponding heat storage body 2, the air outlet of the combustion air blower 12, and the air inlet of the exhaust fan 13. When one furnace chamber 1 is the melting chamber, the other furnace chamber 1 is the heat storage chamber; the melting chamber is connected to the combustion air blower 12, and the heat storage chamber is connected to the exhaust fan 13. The upper part of each furnace chamber 1 has, from top to bottom, a material fluidization inlet 3, a fluidizing air inlet 15, and a fuel inlet 4. The bottom of the molten pool 5 has an outlet for molten material.

[0063] Preferably, there are multiple material fluidization inlets 3, multiple fluidizing air inlets 15, and multiple fuel inlets 4, which are uniformly arranged circumferentially along the furnace 1. The injection axes of the fluidizing air inlets 15 and the fuel inlets 4 are both inclined upwards relative to the horizontal plane.

[0064] Preferably, the upper part of the furnace 1 is provided with a radially expanding and annular feeding chamber 19. Multiple lifting plates 14 are evenly arranged circumferentially on the sidewalls of the feeding chamber 19. The material fluidization inlet 3 is located at the upper end of the lifting plate 14, and the fluidizing air inlet 15 is located at the lower end of the lifting plate 14. The angle between the lifting plate 14 and the horizontal plane is 30°~60°.

[0065] Preferably, the bottom surface of the molten pool 5 includes a central bottom surface 6 located in the middle, and an annular bottom surface 16 surrounding the outer side of the central bottom surface 6. The horizontal projection of the furnace 1 lies within the central bottom surface 6. The center of the central bottom surface 6 is higher than its surroundings, and gradually decreases in height from the center to the surroundings. The annular bottom surface 16 is horizontally positioned. The molten material outlets are located on the annular bottom surface 16, and a plurality of the molten material outlets are evenly arranged along the contour of the annular bottom surface 16.

[0066] Preferably, the horizontal projection of the central bottom surface 6 includes a first circular portion and a second circular portion with equal diameters located at both ends, and a connecting segment connecting the first circular portion and the second circular portion with a width smaller than the diameter of the circular portion. The first circular portion and the second circular portion are respectively directly opposite the two furnace chambers 1 above.

[0067] Preferably, a molten pool weir 9 is provided on the central bottom surface 6, arranged along the contour of the central bottom surface 6. The horizontal projections of the two furnace chambers 1 are both located inside the molten pool weir 9. Multiple molten material channels 10 are provided at the bottom of the molten pool weir 9.

[0068] Preferably, the bottom of the molten pool 5 is provided with a plurality of funnel-shaped discharge channels 7, and each discharge channel 7 is evenly arranged on the annular bottom surface 16 along the contour of the central bottom surface 6. The large end of the discharge channel 7 is connected to the molten pool 5, and the small end of the discharge channel 7 forms the outlet of the molten material.

[0069] Preferably, an iron molten material collection tank 17 is provided between the central bottom surface 6 and the annular bottom surface 16, and the two sides of the opening of the iron molten material collection tank 17 are respectively connected to the central bottom surface 6 and the annular bottom surface 16. The bottom of the iron molten material collection tank 17 is provided with a plurality of iron discharge ports 18, and each iron discharge port 18 is evenly distributed along the contour of the central bottom surface 6.

[0070] Preferably, the system further includes a downstream processing device 8. The downstream processing device 8 is located below the outlet of the molten material. The downstream processing device 8 is one of a forming device, a reduction furnace, a converter, an anode furnace, and an electrolytic cell.

[0071] Preferably, the downstream processing device 8 is a wire drawing device. A stencil is provided at the outlet of the molten material. The wire drawing device is located below the stencil.

[0072] Example 1

[0073] A dual-chamber alternating mineral suspension smelting system includes a melting furnace, a heat storage body 2, a three-way valve 11, a combustion air blower 12, and an exhaust fan 13. The melting furnace includes a molten pool 5 and two furnace chambers 1 arranged side-by-side above the molten pool 5 and connected to each other through the molten pool 5. Each of the two furnace chambers 1 has an airflow inlet at its top, and a heat storage body 2 is correspondingly located at each airflow inlet. The number of three-way valves 11 corresponds to the number of heat storage bodies 2. The three ports of each three-way valve 11 can respectively connect to the corresponding heat storage body 2, the outlet of the combustion air blower 12, and the inlet of the exhaust fan 13. When one furnace chamber 1 is the melting chamber, the other furnace chamber 1 is the heat storage chamber; the melting chamber is connected to the combustion air blower 12, and the heat storage chamber is connected to the exhaust fan 13. The upper part of each furnace chamber 1 has, from top to bottom, a material fluidization inlet 3, a fluidizing air inlet 15, and a fuel inlet 4. The bottom of the molten pool 5 has an outlet for molten material.

[0074] Example 2

[0075] The embodiment 1 is repeated, except that there are eight material fluidization inlets 3, eight fluidizing air inlets 15, and eight fuel inlets 4. The eight material fluidization inlets 3, the eight fluidizing air inlets 15, and the multiple fuel inlets 4 are evenly arranged around the circumference of the furnace 1. The injection axes of the fluidizing air inlets 15 and the fuel inlets 4 are both inclined upwards relative to the horizontal plane.

[0076] Example 3

[0077] The embodiment 2 is repeated, except that the upper part of the furnace 1 is provided with a radially expanding and annular feeding chamber 19. Eight lifting plates 14 are evenly arranged circumferentially on the sidewalls of the feeding chamber 19. The material fluidization inlet 3 is located at the upper end of the lifting plate 14, and the fluidizing air inlet 15 is located at the lower end of the lifting plate 14. The angle between the lifting plate 14 and the horizontal plane is 45°.

[0078] Example 4

[0079] The embodiment 3 is repeated, except that the bottom surface of the molten pool 5 includes a central bottom surface 6 located in the middle, and an annular bottom surface 16 surrounding the outside of the central bottom surface 6. The horizontal projection of the furnace 1 lies within the central bottom surface 6. The center of the central bottom surface 6 is higher than its surroundings, and gradually decreases in height from the center to the surroundings. The annular bottom surface 16 is horizontally positioned. The molten material outlets are located on the annular bottom surface 16, and a plurality of the molten material outlets are evenly arranged along the contour of the annular bottom surface 16.

[0080] Specifically, the central bottom surface 6 is a conical bottom surface.

[0081] Example 5

[0082] The embodiment 4 is repeated, except that the horizontal projection of the central bottom surface 6 includes a first circular portion and a second circular portion with equal diameters located at both ends, and a connecting segment connecting the first and second circular portions with a width smaller than the diameter of the circular portions. The first and second circular portions are respectively directly opposite the two furnace chambers 1 above.

[0083] Example 6

[0084] Example 5 is repeated, except that a molten pool weir 9 is provided on the central bottom surface 6, arranged along the outline of the central bottom surface 6. The horizontal projections of the two furnace chambers 1 are both located inside the molten pool weir 9. Twenty molten material channels 10 are opened at the bottom of the molten pool weir 9.

[0085] Example 7

[0086] The embodiment 6 is repeated, except that the bottom of the molten pool 5 is provided with 20 funnel-shaped discharge channels 7, and each discharge channel 7 is evenly arranged on the annular bottom surface 16 along the contour of the central bottom surface 6. The large end of the discharge channel 7 is connected to the molten pool 5, and the small end of the discharge channel 7 forms the outlet of the molten material.

[0087] Example 8

[0088] The embodiment 7 is repeated, except that an iron molten material collection tank 17 is provided between the central bottom surface 6 and the annular bottom surface 16, and the two sides of the opening of the iron molten material collection tank 17 are respectively connected to the central bottom surface 6 and the annular bottom surface 16. The bottom of the iron molten material collection tank 17 has 20 iron discharge ports 18, and each iron discharge port 18 is evenly distributed along the contour of the central bottom surface 6.

[0089] Example 9

[0090] The system is repeated in Example 8, except that it further includes a downstream processing device 8. The downstream processing device 8 is a wire drawing device. A perforated plate is provided at the outlet of the molten material. The wire drawing device is located below the perforated plate.

Claims

1. A dual-chamber alternating mineral suspension smelting system, characterized in that: The system includes a melting furnace, a heat storage body (2), a three-way valve (11), a combustion fan (12), and an exhaust fan (13). The melting furnace includes a molten pool (5) and two furnace chambers (1) arranged side by side above the molten pool (5) and connected to each other through the molten pool (5). Each of the two furnace chambers (1) has an airflow port at its top, and a heat storage body (2) is correspondingly located at each airflow port. The number of three-way valves (11) is the same as the number of heat storage bodies (2), and they correspond one-to-one. The three ports of the three-way valves (11) are divided into three sections. The furnace can be connected to the corresponding heat storage body (2), the air outlet of the combustion blower (12) and the air inlet of the exhaust fan (13); when one of the furnace chambers (1) is a melting chamber, the other furnace chamber (1) is a heat storage chamber, the melting chamber is connected to the combustion blower (12) and the heat storage chamber is connected to the exhaust fan (13); the upper part of the furnace chamber (1) is provided with a material fluidization inlet (3), a fluidization air inlet (15) and a fuel inlet (4) from top to bottom; the bottom of the molten pool (5) is provided with a molten material outlet.

2. The dual-chamber alternating mineral suspension smelting system according to claim 1, characterized in that: The number of material fluidization inlet (3), fluidization air inlet (15) and fuel inlet (4) are multiple, and the multiple material fluidization inlet (3), multiple fluidization air inlet (15) and multiple fuel inlet (4) are uniformly arranged along the circumference of the furnace (1); the injection axis of the fluidization air inlet (15) and the injection axis of the fuel inlet (4) are both inclined upward relative to the horizontal plane.

3. The dual-chamber alternating mineral suspension smelting system according to claim 2, characterized in that: The upper part of the furnace (1) is provided with a radially expanding and annular feeding chamber (19); the side wall of the feeding chamber (19) is uniformly arranged with multiple lifting plates (14) in the circumferential direction; the material fluidization inlet (3) is opened at the upper end of the lifting plate (14); the fluidization air inlet (15) is opened at the lower end of the lifting plate (14); the angle between the lifting plate (14) and the horizontal plane is 30°~60°.

4. The dual-chamber alternating mineral suspension smelting system according to any one of claims 1 to 3, characterized in that: The bottom surface of the molten pool (5) includes a central bottom surface (6) located in the middle and an annular bottom surface (16) surrounding the outside of the central bottom surface (6); the horizontal projection of the furnace (1) is located within the central bottom surface (6); the center of the central bottom surface (6) is higher than the surrounding area and gradually decreases from the center to the surrounding area; the annular bottom surface (16) is horizontally arranged; the molten material outlet is opened on the annular bottom surface (16), and multiple molten material outlets are evenly arranged along the contour of the annular bottom surface (16).

5. The dual-chamber alternating mineral suspension smelting system according to claim 4, characterized in that: The horizontal projection of the central bottom surface (6) includes a first circular portion and a second circular portion with equal diameters located at both ends, and a connecting segment connected between the first circular portion and the second circular portion with a width smaller than the diameter of the circular portion; the first circular portion and the second circular portion are respectively facing the two furnace chambers (1) above.

6. The dual-chamber alternating mineral suspension smelting system according to any one of claims 1 to 5, characterized in that: A molten pool dam (9) is provided on the central bottom surface (6) along the outline of the central bottom surface (6); the horizontal projections of the two furnace chambers (1) are located inside the molten pool dam (9); multiple molten material channels (10) are opened at the bottom of the molten pool dam (9).

7. The dual-chamber alternating mineral suspension smelting system according to claim 6, characterized in that: The bottom of the molten pool (5) is provided with several funnel-shaped discharge channels (7), and each discharge channel (7) is evenly arranged on the annular bottom surface (16) along the outline of the central bottom surface (6); the large end of the discharge channel (7) is connected to the molten pool (5), and the small end of the discharge channel (7) forms the outlet of the molten material.

8. The dual-chamber alternating mineral suspension smelting system according to any one of claims 1 to 7, characterized in that: A molten iron collection tank (17) is provided between the central bottom surface (6) and the annular bottom surface (16). The two sides of the opening of the molten iron collection tank (17) are connected to the central bottom surface (6) and the annular bottom surface (16) respectively. The bottom of the molten iron collection tank (17) is provided with multiple iron discharge ports (18), and each iron discharge port (18) is evenly distributed along the outline of the central bottom surface (6).

9. The dual-chamber alternating mineral suspension smelting system according to any one of claims 1 to 8, characterized in that: The system also includes a downstream processing device (8); the downstream processing device (8) is located below the outlet of the molten material; the downstream processing device (8) is one of a forming device, a reduction furnace, a converter, an anode furnace, or an electrolytic cell.

10. The dual-chamber alternating mineral suspension smelting system according to claim 9, characterized in that: The downstream processing device (8) is a wire drawing device; a stencil is provided at the outlet of the molten material; the wire drawing device is located below the stencil.

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