Smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing chromium oxide into metal chromium
By designing a smelting device for aluminum chromium slag, using arc heating and hollow ball blowing technology, the purification of alumina and separation of metal chromium is achieved, the problem of aluminum chromium slag treatment is solved, and high-value utilization is achieved.
Patent Information
- Application Number
- CN202411804152.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-10
- Publication Date
- 2025-03-28
AI Technical Summary
The prior art is difficult to effectively treat and utilize aluminum chromium slag, resulting in accumulating a large amount of solid waste in slag state, making it difficult to solve the problem of slag treatment.
A smelting device for separation and purification of chromium oxide in aluminum chromium slag is designed to reduce chromium oxide to metal chromium. Through arc heating and hollow ball blowing technology, alumina purification and metal chromium separation are achieved, avoiding the generation of slag solid waste.
The timely conversion of alumina into products in each furnace is achieved when metal chromium is produced, and solid waste is not generated in slag state, which improves the recovery rate and separation efficiency of chromium in aluminum-chromium slag, and solves the problem of slag treatment.
Smart Images
Figure CN119713837A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an aluminum-chromium slag smelting device, in particular to a smelting device for separating and purifying chromium oxide from the aluminum-chromium slag and reducing it into metallic chromium. Background Art
[0002] When the aluminothermic method is used to produce metallic chromium, a large amount of smelting slag is produced. The main chemical components of this slag are aluminum oxide, followed by chromium oxide, which is called aluminum-chromium slag. This is a solid waste and is listed as a "hazardous waste" in the "National List of Hazardous Wastes" (2025 edition), code-named "314-003-21". Therefore, this solid waste must be harmlessly treated and turned into a valuable raw material.
[0003] At present, there is no very good equipment and method for treating this kind of waste residue. Summary of the invention
[0004] The purpose of the present invention is to provide a smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium. The device of the present invention separates aluminum oxide from the aluminum-chromium slag, purifies it and blows it into hollow balls, and reduces the chromium oxide to metallic chromium. The aluminum oxide produced by each furnace producing metallic chromium is promptly converted into products, and no slag-like solid waste is generated. The state of accumulating a large amount of slag in the traditional aluminothermic method for producing metallic chromium is overcome, and the problem of slag treatment is solved. The present invention is a smelting device for high-value utilization of waste slag.
[0005] The objective of the present invention is achieved through the following technical solutions: A smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium, the device comprising a furnace frame, an electrode cross arm, an electrode lifting mechanism, a dust extraction port, an upper furnace cover, a furnace body, a middle furnace cover, a mobile rail car, a support frame for replacing the furnace shell, a furnace shell lifting cylinder, rails, a furnace body platform, a furnace shell hanging connection mechanism, a blowing ball blowing nozzle, a furnace tilting cylinder, a furnace shell, a water-cooled spray pipe, a graphite electrode, a furnace discharge nozzle, a water-cooled cable, and a transformer; the furnace frame is connected to a concrete foundation with anchor bolts; the furnace body sits on the furnace frame, is fixed with positioning pins and connected to the furnace frame as a whole; the middle furnace cover falls on the furnace body and is connected to the furnace body with bolts; the upper furnace cover is on the upper part of the middle furnace cover and is connected with bolts; the upper furnace cover is provided with a dust extraction port, and the smoke generated by the melting reaction in the furnace is discharged through the dust extraction port and enters the dust removal system; The furnace shell is at the bottom of the furnace body, and is connected to the furnace body by a hanging connection mechanism; the hanging connection mechanism is provided with a locking device; a cooling water spray pipe is provided outside the furnace shell to spray water outside the furnace shell for cooling; the mobile rail car travels on the rails; the support frame for replacing the furnace shell sits on the mobile rail car; the lower part of the support frame for replacing the furnace shell is provided with a lifting cylinder; This device is used to treat slag containing precious metals. The process is: The slag containing precious metals is melted in this equipment, so that the melt in the furnace maintains a low viscosity, so that the precious metal components will be deposited and agglomerated at the bottom of the furnace shell. At this time, the upper layer of the melt in the furnace does not contain precious metal components. This part of the melt is poured out of the furnace and blown into hollow balls. After the slag is heated by the electric arc, the slag becomes liquid and the viscosity decreases. The precious metal components can be deposited and enriched at the bottom of the furnace. The part without precious metals can be blown into hollow balls for use as insulation materials. After the furnace shell is replaced, the solidified body in it after cooling is a new type of slag with increased precious metal content. The process of refining precious metals using this slag is simplified. When the precious metal components at the bottom of the furnace accumulate, the furnace shell is replaced, and the melt in the furnace shell is a melt with a relatively high content of precious metal components. After it is dug out from the furnace shell, this device plays a role in enriching the precious metal components in the precious metal slag with a low content. This device is used to produce metallic chromium by aluminothermic method. The process is: A mixture of chromium oxide and metallic aluminum powder is added to the furnace shell to react with chromium oxide being reduced to metal, and metallic chromium settles to the bottom of the furnace shell, while molten aluminum oxide is on the upper layer; after the reaction is completed, the reaction product is supplemented with heat, and the electrodes are energized to heat the molten aluminum oxide on the upper layer with an electric arc to reduce the viscosity of the molten aluminum oxide and promote the reduced metallic chromium to settle downward; then the furnace body is tilted to blow the aluminum oxide into hollow balls; a mixture of chromium oxide and metallic aluminum powder is added to the furnace again, and the reaction process is repeated; this process is repeated more than 3 times, and the furnace shell is replaced; the reaction product of the aluminothermic process for producing metallic chromium is supplemented with heat by electric arc heating, so that the temperature of the generated alumina slag liquid is increased and the viscosity is reduced, thereby accelerating the settling speed of the metallic chromium in the slag liquid; the molten aluminum oxide generated each time is blown into hollow aluminum oxide balls in a timely manner, thereby reducing the amount of alumina slag generated when producing metallic chromium by the aluminothermic process.
[0006] In the smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium, the axis of the dust extraction port forms an angle of 45° with the horizontal plane of the upper furnace cover.
[0007] In the smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium, the furnace shell is replaced so that the metallic chromium reduced from chromium oxide remains in the furnace shell, and a layer of aluminum oxide melt is covered on the metallic chromium; by replacing the furnace shell, it is ensured that the separated metallic chromium is not oxidized, thereby improving the separation efficiency.
[0008] The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium uses electric arc heating to melt a mixture of aluminum-chromium slag and a carbon reducing agent, and the chromium oxide in the slag is reduced to metallic chromium and deposited at the bottom of the furnace, and the upper layer is aluminum oxide melt, thereby achieving the separation of aluminum oxide and metallic chromium.
[0009] The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium, the carbon reducing agent is petroleum coke, blue coke, charcoal, graphite block, and the weight ratio of slag to reducing agent is 100 / 4 to 100 / 8.
[0010] The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium has a melting cycle of 4 hours, a voltage of 180-220V, and a current of 4000-10000A. After the melting is completed, the molten liquid is layered, the upper layer is aluminum oxide molten liquid, and the lower layer is metallic chromium molten liquid.
[0011] The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium, when the upper layer of aluminum oxide melt in the furnace flows out, the flow of the aluminum oxide melt is blown by compressed air to disperse the aluminum oxide melt to form hollow balls; in this process, the oxygen in the compressed air oxidizes the residual carbon in the aluminum oxide melt to purify the aluminum oxide; at the same time, the hollow balls fly in the air, which is also a process of cooling themselves down.
[0012] The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium has a compressed air pressure of 0.4MPa-0.8MPa and a flow rate of 10-20M3 / min for blowing the hollow aluminum oxide balls.
[0013] The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium is characterized in that the furnace shell is replaced after the device is repeatedly produced for 3 to 5 furnaces.
[0014] The advantages and effects of the present invention are: 1. The present invention has designed a method that the furnace shell can be removed and replaced. This solves the problem that the metal chromium in the furnace cannot be completely discharged when the furnace body is tilted to the maximum angle; at the same time, it avoids the problem that the liquid metal chromium stream is oxidized by air when the furnace body is tilted. This method of replacing the furnace shell improves the effect of separating chromium from alumina in aluminum-chromium slag and also improves the recovery rate of chromium in the slag.
[0015] 2. The advantage of using this equipment to produce chromium metal by aluminothermic method is that the alumina produced in each furnace is converted into products in time, and no slag-like solid waste is generated. This changes the state of accumulating a large amount of slag in the traditional aluminothermic method of producing chromium metal, and solves the problem of slag treatment. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a front view of the structure of the device of the present invention; Figure 2 It is a left side view of the structure of the device of the present invention; Figure 3 This is a schematic diagram of a state in which the mobile rail car and the furnace shell support of the device of the present invention are not under the furnace shell; Figure 4It is a schematic diagram of the mobile rail car and furnace shell support of the present invention. DETAILED DESCRIPTION
[0017] The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.
[0018] The equipment for separating and purifying aluminum oxide in aluminum-chromium slag and reducing chromium oxide to metal chromium of the present invention comprises a furnace frame 1, an electrode cross arm 2, an electrode lifting mechanism 3, a dust extraction port 4, an upper furnace cover 5, a furnace body 6, a middle furnace cover 7, a mobile rail car 8, a support frame 9 for replacing the furnace shell, a furnace shell lifting oil cylinder 10, a rail 11, a furnace body platform 12, a furnace shell hanging connection mechanism 13, a blowing ball blowing nozzle 14, a furnace tilting oil cylinder 15, a furnace shell 16, a water-cooling spray pipe 17, a graphite electrode 18, a furnace discharge nozzle 19, a water-cooling cable 20, and a transformer 21. The furnace frame 1 is connected to the concrete foundation by anchor bolts. The furnace body 6 sits on the furnace frame 1, is fixed by a positioning pin and connected to the furnace frame as a whole; the middle furnace cover 7 falls on the furnace body 6 and is connected to the furnace body by bolts; the upper furnace cover 5 is on the upper part of the middle furnace cover 6 and is connected by bolts. The upper furnace cover 5 is provided with a dust extraction port 4, and the smoke generated by the melting reaction in the furnace is discharged through the dust extraction port 4 and enters the dust removal system. The axis of the dust extraction port 4 is at an angle of 45° to the horizontal plane of the upper furnace cover 5. The furnace shell 16 is at the lower part of the furnace body 6, and the furnace shell and the furnace body are connected together by a hanging connection mechanism 13. The hanging connection mechanism is provided with a locking device. There is a cooling water spray pipe 17 outside the furnace shell, which sprays water to the outside of the furnace shell to cool it down and ensure the safety of the furnace shell. The mobile rail car 8 travels on the rails 11; the support frame 9 for replacing the furnace shell sits on the mobile rail car 8; the lower part of the support frame 9 for replacing the furnace shell has a lifting cylinder 10. Generally, the mobile rail car 8 and the support frame 9 for replacing the furnace shell are not under the furnace shell. They are only moved under the furnace shell when the furnace shell needs to be replaced. When replacing the furnace shell, the furnace shell is supported by the lifting cylinder 10, and then the locking device of the hanging connection mechanism is opened, and the lifting cylinder descends. At this time, the furnace shell 16 is disconnected from the furnace body 6. The mobile rail car drags the furnace shell away from under the furnace body. Then the mobile rail car drags another furnace shell to the bottom of the furnace body, the lifting cylinder rises to dock the furnace shell with the furnace body, and then the furnace shell and the furnace body are connected together with the hanging connection mechanism, and the locking device is locked. The lifting cylinder descends, and the mobile rail car moves away from the bottom of the furnace shell together with the furnace shell support frame. The power supply of the equipment, the external power supply supplies electricity to the electrode cross arm 2 through the transformer and cable, and the electrode cross arm 2 sends electricity to the graphite electrode 18. 500mm high-alumina refractory bricks and 300 thick graphite bricks are laid at the bottom of the furnace shell. Then 300-400mm thick slag is laid on the graphite bricks. Graphite blocks are laid on the slag, and the size of the graphite blocks is 30-50mm. After the transformer is powered on, the graphite electrode is voltaged, and when the descending graphite electrode is close to the graphite block on the slag layer, a plasma arc will be generated between the graphite electrode and the graphite block. The arc melts the slag and increases the temperature, and melts the subsequent added materials. When a stable plasma arc is formed between the graphite electrode and the liquid slag, a mixture of slag and graphite blocks is added to the furnace shell. The carbon in the graphite reacts with the chromium oxide in the slag, reducing the chromium oxide to metallic chromium that settles to the bottom of the furnace shell, and the upper molten liquid is alumina molten liquid. Blue coke, petroleum coke, etc. can be used as a reducing agent instead of graphite. The weight ratio of slag to carbon reducing agent is 100 / 4 to 100 / 8.Melt while adding materials until the liquid level approaches the level of the furnace nozzle. Refining for another 40 minutes to 1 hour, the molten metal has begun to stratify. The upper layer is alumina molten metal, which has a larger volume because the content of alumina in the slag is relatively high, generally accounting for 80% to 90%. The lower layer is a molten metal chromium, which has a smaller volume because the content of chromium oxide in the slag is relatively low, generally accounting for 10% to 20%, and because chromium oxide is reduced to metallic chromium. Then it starts to be discharged from the furnace. The time of a melting cycle is about 4 to 5 hours, the voltage is 180 to 220V, and the current is 4000 to 10000A. When the furnace is discharged after a melting cycle, the tilting hydraulic cylinder rises, the furnace body tilts, the molten metal flows out from the furnace nozzle 19, and the compressed air comes out from the ball blowing nozzle 14. The compressed air blows the stream of the molten metal to form a hollow ball. The pressure of the compressed air is 0.4MPa to 0.8MPa, and the flow rate is 10 to 20M3 / min. In this process, the oxygen in the compressed air oxidizes the residual carbon in the alumina melt to purify the alumina; at the same time, the hollow ball flies in the air, which is also a process of cooling itself. The hollow ball is screened to obtain hollow balls of different particle sizes. This hollow ball is a product after the separation of the waste slag. This hollow ball is a high-grade thermal insulation material and can also be used as a spray abrasive.
[0019] After repeating the production for 3 to 5 batches according to the above process, the furnace shell needs to be replaced. Because less metal chromium settles in each batch, after 3 to 5 batches, a certain amount of metal chromium accumulates at the bottom of the furnace shell, but it is not particularly large. If the liquid metal chromium is poured out of the furnace by increasing the tilting angle of the furnace, even when the furnace body is tilted to the maximum angle of 45°, the liquid metal chromium in the furnace shell cannot flow out, and some liquid metal chromium remains at the bottom of the furnace shell. In addition, due to the process of pouring the liquid metal chromium out of the furnace, the stream of liquid metal chromium contacts the air, and some metal chromium is oxidized into metal. Based on these two situations, the method of pouring the liquid metal chromium out of the furnace cannot be used.
[0020] The present invention has designed a method in which the furnace shell can be removed and replaced. The lower part of the furnace shell is liquid metallic chromium, and the upper part is covered with a layer of molten aluminum oxide, which plays a role in protecting the metallic chromium from oxidation. The process of removing and replacing the furnace shell is carried out as described above. The removed furnace shell is moved to a designated position for natural cooling. After cooling, the solidified body in the furnace shell is dug out, and the upper layer of aluminum oxide returns to the aforementioned process; the metallic chromium in the lower layer is used as another product of the waste slag separation. This method of replacing the furnace shell improves the effect of separating chromium from aluminum oxide in the aluminum-chromium slag, and also improves the recovery rate of chromium in the slag.
[0021] Used in the aluminothermic process to produce metallic chromium. A mixture of chromium oxide and metallic aluminum powder is added to the furnace shell to undergo the following reaction: Cr2O3+2Al→2Cr+Al2O3.
[0022] The metallic chromium settles to the bottom of the furnace shell, and the molten alumina is on the upper layer. According to the traditional process, the heat release of the aluminothermic reaction is used, and the reactants are in liquid state, and there is no subsequent heating of the reaction products. After the reaction is completed, the electrode is lowered, and the upper layer of the molten alumina is heated by a plasma arc to reduce the viscosity of the molten alumina and promote the reduced metallic chromium to settle downward. That is, the reaction products are supplemented with heat on the basis of the traditional process. Then the furnace body is tilted to blow the upper layer of the molten alumina into hollow balls. This converts the slag of the aluminothermic production of metallic chromium into alumina hollow ball products in a timely manner. Operate as described above. Leave a thin layer of molten alumina in the furnace shell. Add a mixture of chromium oxide and metallic aluminum powder to the furnace, and repeat the process of producing metallic chromium by the aluminothermic method. This process can be repeated more than 3 times, and then the furnace shell is replaced. The operation of changing the furnace shell is carried out as described above. The amount of liquid metallic chromium in the replaced furnace shell is large, and a thin layer of molten alumina is covered on it, which plays a role in protecting the liquid metallic chromium from oxidation. The replaced furnace shell is moved to the designated position, and after cooling, the metal chromium in the furnace shell is dug out as the product; the upper layer of alumina solidifies into blocks, and a small amount is produced each time. After accumulating a certain amount, alumina hollow balls can be blown. The empty furnace shell is used for the next process cycle.
[0023] The production of metallic chromium is that the alumina produced in each furnace of metallic chromium production is promptly converted into alumina hollow ball products, and no slag-like solid waste is generated. This changes the state of accumulating a large amount of slag when producing metallic chromium by the traditional aluminothermic method, and solves the problem of slag treatment.
[0024] For the treatment of slag containing precious metals with a relatively low content, according to the aforementioned similar process, the slag containing precious metals is melted in this equipment, so that the melt in the furnace maintains a relatively low viscosity, so that the atoms of the precious metal components will be deposited and agglomerated at the bottom of the furnace shell, and then the upper layer of the melt in the furnace does not contain precious metal components, and this part of the melt is poured out of the furnace and blown into hollow balls. Such hollow balls can be used as thermal insulation materials, etc. When the precious metal components at the bottom of the furnace accumulate to a certain amount, the furnace shell is replaced, and the melt in the furnace shell is the melt of the precious metal components. After digging it out of the furnace shell, other separation methods are used to separate the precious metals from the melt block. The equipment of the present invention can play a role in enriching the precious metal components in the precious metal slag with a relatively low content. Embodiment 1
[0025] A 2800KVA transformer is used, the furnace shell diameter is 2200mm, and the electrode diameter is 250mm. The refractory brick and graphite brick protective layer at the bottom of the furnace shell is 900mm thick. Then 300mm thick slag is laid on this furnace bottom protective layer. Then graphite blocks are laid, and the size of the graphite blocks is about 30mm.
[0026] The transformer supplies power to the electrode. When the lower electrode is close to the graphite block on the slag, an arc is generated. The arc heats the slag. At this time, the voltage is 170V and the current is 6000A. This stage lasts for 20 minutes. The current may fluctuate at the beginning, and the current is stable in about 20 minutes. Add a mixture of slag and petroleum coke into the furnace shell, with the weight ratio of slag to petroleum coke being 100 / 5. Melt while adding until the liquid level approaches the furnace nozzle. Refine for another 40 minutes to 1 hour, and the molten liquid has begun to stratify. The upper layer is alumina molten liquid, and the bottom of the furnace shell is metallic chromium. At this time, the voltage is 180V and the current is 7000A. Adjust the voltage to 190V and the current to 5000A, the tilting hydraulic cylinder rises, the furnace body tilts, the molten liquid flows out from the furnace nozzle (19#), and compressed air comes out from the blowing nozzle 14. The compressed air blows the stream of the molten liquid to form a hollow ball. The pressure of compressed air is 0.6MPaPa, and the flow rate is 15M3 / min. In this process, the oxygen in the compressed air oxidizes the residual carbon in the alumina melt to purify the alumina; at the same time, the hollow balls fly in the air, which also cools themselves. Finally, the hollow balls are screened to obtain hollow balls of different particle sizes.
[0027] Repeat the above operation 4 times before changing the furnace shell. The furnace shell is supported by the lifting cylinder 10, and then the locking device of the hanging connection mechanism is opened, and the lifting cylinder is lowered. At this time, the furnace shell 16 is disconnected from the furnace body 6. The mobile rail car drags the furnace shell from under the furnace body. Then the mobile rail car drags another furnace shell to the bottom of the furnace body, and the lifting cylinder rises to connect the furnace shell with the furnace body, and then the furnace shell and the furnace body are connected together with the hanging connection mechanism, and the locking device is locked. The lifting cylinder is lowered, and the mobile rail car is removed from under the furnace shell together with the bracket. After the furnace shell with molten liquid is cooled and solidified, the material in it is dug out, and the upper layer of alumina returns to step 2 for melting; after the bottom layer of metallic chromium is dug out, it is the product metallic chromium. Embodiment 2
[0028] A 1500KVA transformer is used, the furnace shell diameter is 2000m, and the electrode diameter is 200mm. The furnace bottom can be paved with 500mm thick high-alumina refractory bricks and 300 thick corundum bricks. A mixture of chromium oxide and metal aluminum powder is added to the furnace shell, ignited with a magnesium strip, and an aluminothermic reaction is carried out in the furnace shell to reduce chromium oxide to metal chromium, and metal aluminum becomes alumina floating on the surface. When the liquid level approaches the furnace nozzle, the feeding is stopped. The flue gas generated during the reaction is discharged into the dust removal system through the dust extraction port. After power is turned on, the descending electrode generates an arc between the electrode and the alumina melt to heat the alumina melt. The time is 30 minutes, the voltage is 200V, and the current is 4000A. In this process, the temperature of the alumina melt increases, the viscosity decreases, and the reduced metal chromium in the melt settles faster. The furnace body tilts, the molten liquid flows out from the furnace outlet 19, and the compressed air comes out from the ball blowing nozzle 14. The compressed air blows the stream of the molten liquid to form hollow balls. The pressure of the compressed air is 0.5MPaPa, and the flow rate is 10M3 / min. The tilting of the furnace is completed when a small amount of alumina melt is left in the furnace. In this process, the hollow balls fly in the air, which also cools down themselves. Finally, the hollow balls are screened to obtain hollow balls of different particle sizes. In this way, when the aluminothermic method is used to produce metallic chromium, the alumina produced in each furnace is converted into products in time, and no accumulated waste slag is generated.
[0029] The above process is repeated 3 times. After the alumina melt in the furnace shell is blown into alumina balls, a small amount of alumina melt is left, and then the furnace shell is replaced. The furnace shell is supported by the lifting cylinder 10, and then the locking device of the hanging connection mechanism is opened, and the lifting cylinder is lowered. At this time, the furnace shell 16 is disconnected from the furnace body 6. The mobile rail car drags the furnace shell away from the bottom of the furnace body. Then the mobile rail car drags another furnace shell to the bottom of the furnace body, and the lifting cylinder rises to dock the furnace shell with the furnace body, and then the furnace shell and the furnace body are connected together with the hanging connection mechanism, and the locking device is locked. The lifting cylinder is lowered, and the mobile rail car is removed from the bottom of the furnace shell together with the furnace shell bracket. After the furnace shell with molten liquid is cooled and solidified, the material in it is dug out, and the upper layer of alumina returns to step 3 for melting; after the metal chromium in the lower layer is dug out, it is the product metal chromium. The produced metal chromium is the alumina produced in each furnace production process, which is blown into alumina hollow ball products in time, so that there is no accumulated waste slag, which solves the difficulty of waste slag treatment.
Claims
1. A smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium, characterized in that: The device comprises a furnace frame (1), an electrode cross arm (2), an electrode lifting mechanism (3), a dust extraction port (4), an upper furnace cover (5), a furnace body (6), a middle furnace cover (7), a mobile rail car (8), a support frame for replacing a furnace shell (9), a furnace shell lifting cylinder (10), a rail (11), a furnace body platform (12), a furnace shell hanging connection mechanism (13), a blowing ball nozzle (14), a furnace tilting cylinder (15), a furnace shell (16), a water cooling spray pipe (17), a graphite electrode (18), and a furnace discharge device. A furnace nozzle (19), a water-cooling cable (20), and a transformer (21); the furnace frame (1) is connected to the concrete foundation by anchor bolts; the furnace body (6) sits on the furnace frame (1), is fixed by positioning pins and is connected to the furnace frame as a whole; the middle furnace cover (7) falls on the furnace body (6) and is connected to the furnace body by bolts; the upper furnace cover (5) is on the upper part of the middle furnace cover (6) and is connected by bolts; the upper furnace cover (5) is provided with a dust extraction port (4), and the smoke generated by the melting reaction in the furnace is discharged through the dust extraction port (4) and enters the dust removal system; The furnace shell (16) is at the lower part of the furnace body (6), and is connected to the furnace body through a hanging connection mechanism (13); the hanging connection mechanism is provided with a locking device; a cooling water spray pipe (17) is provided outside the furnace shell to spray water outside the furnace shell for cooling; a mobile rail car (8) travels on rails (11); a support frame (9) for replacing the furnace shell sits on the mobile rail car (8); a lifting cylinder (10) is provided at the lower part of the support frame (9) for replacing the furnace shell; This device is used to treat slag containing precious metals. The process is: The slag containing precious metals is melted in this equipment, so that the melt in the furnace maintains a low viscosity, so that the precious metal components will be deposited and agglomerated at the bottom of the furnace shell. At this time, the upper layer of the melt in the furnace does not contain precious metal components. This part of the melt is poured out of the furnace and blown into hollow balls. After the slag is heated by the electric arc, the slag becomes liquid and the viscosity decreases. The precious metal components can be deposited and enriched at the bottom of the furnace. The part without precious metals can be blown into hollow balls for use as insulation materials. After the furnace shell is replaced, the solidified body in it after cooling is a new type of slag with increased precious metal content. The process of refining precious metals using this slag is simplified. When the precious metal components at the bottom of the furnace accumulate, the furnace shell is replaced, and the melt in the furnace shell is a melt with a relatively high content of precious metal components. After it is dug out from the furnace shell, this device plays a role in enriching the precious metal components in the precious metal slag with a low content. This device is used to produce metallic chromium by aluminothermic method. The process is: A mixture of chromium oxide and metallic aluminum powder is added to the furnace shell to react with chromium oxide being reduced to metal, and metallic chromium settles to the bottom of the furnace shell, while molten aluminum oxide is on the upper layer; after the reaction is completed, the reaction product is supplemented with heat, and the electrodes are energized to heat the molten aluminum oxide on the upper layer with an electric arc to reduce the viscosity of the molten aluminum oxide and promote the reduced metallic chromium to settle downward; then the furnace body is tilted to blow the aluminum oxide into hollow balls; a mixture of chromium oxide and metallic aluminum powder is added to the furnace again, and the reaction process is repeated; this process is repeated more than 3 times, and the furnace shell is replaced; the reaction product of the aluminothermic process for producing metallic chromium is supplemented with heat by electric arc heating, so that the temperature of the generated alumina slag liquid is increased and the viscosity is reduced, thereby accelerating the settling speed of the metallic chromium in the slag liquid; the molten aluminum oxide generated each time is blown into hollow aluminum oxide balls in a timely manner, thereby reducing the amount of alumina slag generated when producing metallic chromium by the aluminothermic process.
2. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: The axis of the dust extraction port (4) forms an angle of 45° with the horizontal plane of the upper furnace cover (5).
3. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: The furnace shell is replaced so that the metal chromium reduced by chromium oxide remains in the furnace shell, and a layer of molten aluminum oxide covers the metal chromium. By replacing the furnace shell, the separation efficiency is improved by ensuring that the separated metal chromium is not oxidized.
4. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: The mixture of aluminum-chromium slag and carbon reducing agent is melted by electric arc heating, and the chromium oxide in the slag is reduced to metallic chromium and deposited at the bottom of the furnace, and the upper layer is aluminum oxide melt, thereby achieving the separation of aluminum oxide and metallic chromium.
5. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: The carbon reducing agent is petroleum coke, blue carbon, charcoal, or graphite block, and the weight ratio of slag to reducing agent is 100 / 4 to 100 / 8.
6. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: The melting cycle is 4 hours; the voltage is 180-220V, and the current is 4000-10000A; after the melting is completed, the melt is layered, the upper layer is the aluminum oxide melt, and the lower layer is the metal chromium melt.
7. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: When the upper layer of molten aluminum oxide in the furnace flows out, compressed air is used to blow the stream of the molten aluminum oxide to disperse the molten aluminum oxide to form hollow balls. In this process, the oxygen in the compressed air oxidizes the residual carbon in the molten aluminum oxide to purify the aluminum oxide. At the same time, the hollow balls fly in the air, which is also a process of cooling themselves down.
8. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: The device blows the aluminum oxide hollow balls with compressed air at a pressure of 0.4 MPa to 0.8 MPa and a flow rate of 10 to 20 M3 / min.
9. The smelting device for separating and purifying chromium oxide from aluminum-chromium slag and reducing it to metallic chromium according to claim 1, characterized in that: After the device repeats production for 3 to 5 times, the furnace shell is replaced.