CN204848984U - Electromagnetic induction heating melting reducing metal magnesium vacuum reduction stove - Google Patents

Abstract

The utility model relates to the technical field of vacuum metallurgy equipment, in particular to a vacuum reduction furnace for electromagnetic induction heating, melting and reduction of metal magnesium, comprising a furnace body (1), and the furnace body is provided with a hopper (4) made of hard heat insulating material , the central part of the hopper is provided with a central passage through the bottom surface of the hopper; the bottom surface of the hopper is concentrically provided with one or more annular grooves (7), and the grooves (7) are provided with solid or molten state The furnace body (1) is provided with a rectangular iron core (6), one side of the rectangular iron core passes through the central channel of the hopper (4), and the other side of the rectangular iron core (6) A primary side coil (9) is wound; the lead-out end of the copper winding of the primary side coil (9) is led out of the furnace through an insulating sealing device on the furnace body to be connected with a power supply device. The utility model has reasonable design, can adjust the distribution of the temperature field of the reduction furnace, and has fast heat transfer efficiency; it is used for the production of magnesium, lithium, strontium, calcium and other high vapor pressure metal thermal reduction methods.

Description

Electromagnetic Induction Heating Melting Reduction Metal Magnesium Vacuum Reduction Furnace

technical field

The utility model relates to the technical field of vacuum metallurgy equipment, in particular to a vacuum reduction furnace for melting and reducing metal magnesium by electromagnetic induction, which can be used for preparing magnesium, lithium, strontium, calcium and other high vapor pressure metals by thermal reduction.

Background technique

Metals with high vapor pressure such as magnesium, lithium, strontium, and calcium can be prepared under vacuum conditions by thermal reduction. At present, in the field of metal magnesium production, the widely used reduction equipment is to directly heat the reduction tank made of heat-resistant alloy with gas or the like. This method is limited by the structure and material properties of the reduction tank, the reaction temperature is low, the heat transfer is slow, the energy consumption is high, and a large amount of expensive nickel-chromium alloy is consumed due to the oxidation of the reduction tank.

The electrothermal smelting reduction furnace can overcome the problems of high energy consumption and reduction tank consumption of the external heating reduction furnace. Such as U.S.Patent2,971,833 just disclosed a kind of molten state magnesium reduction furnace of AC resistance furnace principle in 1961. The reduction is carried out in a graphite-lined electroslag conduction furnace. The AC power passes through the upper graphite electrode, melts the conductive slag, and the graphite lining forms a loop. The Joule heating effect of the loop current keeps the conductive slag in a molten state and provides the heat required for the reduction reaction. The reduction reaction occurs in two ways: liquid-solid and liquid-liquid. Reaction in the liquid state, the mass transfer of the substance is easier than that in the solid state, so the reaction speed is fast and the reduction time is greatly shortened. The raw materials are all fed into the furnace in blocks, and there is no need for crushing, ball making and briquetting, which greatly reduces labor costs and improves production efficiency. U.S.Patent 4,699,653 disclosed a molten metal magnesium reduction furnace called MINTEK in 1987. The furnace uses a direct current arc to heat the conductive slag in the graphite-lined furnace, and the current also passes through the graphite electrode to melt the conductive slag, and the graphite lining forms a circuit.

The problem existing in the prior art is: firstly, primary slag needs to be placed in the furnace. When the furnace is started from a cold state, additional facilities and operations are required, the start-up process is complicated, and the application is inconvenient. Graphite electrodes and graphite linings suffer large losses at high temperatures, and equipment maintenance costs are high.

Contents of the invention

Aiming at the technical problems of the existing electrothermal melting state vacuum reduction furnace, the utility model provides an electromagnetic induction heating melting reduction metal magnesium vacuum reduction furnace, which is used for the production of magnesium, lithium, strontium, calcium and other high vapor pressure metal thermal reduction methods.

The utility model is realized by adopting the following technical solutions:

An electromagnetic induction heating melting reduction metal magnesium vacuum reduction furnace, comprising a furnace body, the furnace body is provided with a hopper made of hard heat insulating material, the central part of the hopper is provided with a central channel passing through the bottom surface of the hopper, the hopper The section on any radius is U-shaped; one or more annular grooves are concentrically arranged on the bottom surface of the hopper, and solid or molten iron is arranged in the grooves.

The furnace body is provided with a rectangular iron core, one side of the rectangular iron core passes through the central channel of the hopper, and the other side of the rectangular iron core is wound with a primary coil; the copper winding of the primary coil leads out The end is led out of the furnace through the insulating sealing device on the furnace body and connected with the power supply device.

An insulating layer is arranged between the furnace body and the hopper; an insulating layer is arranged between the rectangular iron core and the hopper; then the insulating layer, the hopper and the rectangular iron core are spliced and fixed.

A feed channel is provided on the top of the furnace body, and the feed channel passes through the insulation layer and communicates with the hopper.

A slagging passage is provided at the bottom of the furnace body, and the slagging passage passes through the insulation layer and the hopper and communicates with the bottom of the hopper inner cavity.

The upper part of the furnace body is connected to the crystallization chamber through a metal steam channel, an insulation layer is arranged in the metal steam channel, and a coarse suction port is opened on the metal steam channel.

A water cooling jacket is installed outside the crystallization chamber, and a fine extraction port is provided on the upper part of the crystallization chamber.

When working, firstly, the powdery reducing charge is loaded into the bottom of the hopper through the feeding channel on the top of the furnace body, and directly contacts with the iron and residual slag (residue from the last smelting) at the bottom of the hopper. The upper part of the powdered reduction charge is filled with granular or block charge. The high-frequency alternating current applied to the copper winding by the power supply unit generates an alternating magnetic field in the iron core. The alternating magnetic field generates an induced current in the ring iron at the bottom of the hopper, and the heat generated by the current heats the residual slag and furnace charge through conduction and radiation. When the charge and slag are heated to a molten state, they also have electrical conductivity, and the induced current inside it also generates heat to jointly heat the charge. Through this electromagnetic induction process, electric energy is transmitted to the iron ring and molten slag without contact to heat the reaction charge and supply the reduction reaction. With the melting of the charge, the reduction reaction occurs in two ways: liquid-solid and liquid-liquid. Finally, the charge is completely melted, and the reduction reaction is completed.

There is a slag outlet on one side of the bottom of the hopper. After the reduction reaction is completed, break the vacuum and open the slag discharge port, and the liquid slag will flow out automatically; the air pump can also be used to pressurize the material slag to quickly discharge. Due to the difference in density, the heavier molten iron sinks in the groove at the bottom of the hopper and will not be discharged, which is used to induce current to generate heat at the beginning of the next working cycle; the excess molten iron is discharged together with the slag, due to the different density, The molten iron can be collected separately from the slag outside the furnace.

During the reduction process, a rough pumping port is used to pump air during the rough vacuuming stage, so that the floating dust in the furnace gas will not be deposited in the crystallization chamber and reduce the purity of crystalline magnesium. When a higher vacuum degree is reached, the gas flow rate is very low at this time, the rough pumping port is closed, and the vacuum is drawn from the fine pumping port passing through the crystallization chamber.

Preferably, one side of the iron core is located on the axis of the cylindrical furnace chamber and passes through the center of the hollow cylindrical hopper, and the other three sides of the iron core are close to the wall of the furnace shell.

Further, in order to make the charging of the reduction furnace more convenient.

There are multiple feeding channels on the top of the design reduction chamber, from which the charge falls naturally into the hopper.

Compared with the prior art, the utility model has the following advantages:

1. The hopper is made of hard thermal insulation material, no conductive graphite lining is needed, the cost is low, it is not easy to be damaged under high temperature, and the operation and maintenance cost is low.

2. The initial heating element is the iron in the groove at the bottom of the hopper. During the reduction process, the residual low-silicon iron in the furnace charge will continuously replenish it, and the excess molten iron will be discharged together with the slag. The initial heating element requires no maintenance during operation.

3. The slag in the hopper can be discharged as much as possible, and there is no need to leave the residue as a heating element when restarting. The space in the hopper can be more reserved for the newly loaded charge. In this way, the reduction furnace can adopt a batch production process similar to the Pidgeon method to obtain a product with higher purity than the existing process.

4. The distribution of the number of annular grooves at the bottom of the hopper is designed according to the needs of the thermal field. During the heating process, the temperature distribution is uniform and there is no hot spot.

5. The power supply device applies power to the primary side coil of an equivalent transformer, the power supply voltage is high, and the current of the feeding electrode is small. At the same time, the feed electrode is not in contact with the heating body, so there is no need to use water-cooled electrodes, the structure of the furnace body is simple, and the heat loss is small.

6. The residual low-silicon ferrosilicon after the charge reduction reaction can be recovered.

7. The reduction furnace does not need continuous feeding during the working process, and the one-time feeding method will not damage the heating current circuit, so that the reduction furnace can also adopt an intermittent production process similar to the Pidgeon method, which is convenient for integration with the existing Pidgeon method. It is compatible with the traditional process, which reduces the difficulty and risk of process conversion.

8. The furnace shell is integrally formed without moving parts, and the furnace shell is easy to realize sealing, allowing the reduction process to be carried out under various vacuum conditions.

The utility model has reasonable design, can adjust the distribution of the temperature field of the reduction furnace, and has fast heat transfer efficiency; it is mainly used for the production of magnesium, lithium, strontium, calcium and other high-vapor-pressure metal thermal reduction methods.

Description of drawings

Fig. 1 shows the structural representation of the utility model.

Figure 2 shows a cross-sectional view of the electromagnetic assembly.

In the figure, 1-furnace body, 2-crystallization chamber, 3-reduction charge, 4-hopper, 5-metal steam channel, 6-rectangular iron core, 7-groove, 8-insulation layer, 9-primary side coil, 10-Feeding channel, 11-Slag discharge channel, 12-Water cooling pipe, 13-Coarse pumping port, 14-Fine pumping port, 15-Water cooling jacket.

Detailed ways

Specific embodiments of the present utility model will be described in detail below in conjunction with the accompanying drawings.

An electromagnetic induction heating melting reduction metal magnesium vacuum reduction furnace includes a furnace body and is a vertical furnace.

As shown in Figure 1, the furnace body 1 is provided with a hopper 4 made of hard heat insulating material, and the central part of the hopper 4 is provided with a central channel passing through the bottom surface of the hopper 4, and the section of the hopper on any radius is approximately It is U-shaped; the bottom surface of the hopper 4 is concentrically provided with one or more annular grooves 7, and solid or molten iron is arranged in the grooves 7, and the annular iron is used as a heating body. The cross-sectional shape of the groove 7 is an inverted trapezoid with a long top and a short bottom.

As shown in Figure 1, the furnace body 1 is provided with a rectangular iron core 6, one side of the rectangular iron core 6 passes through the central channel of the hopper 4 and is located on the central axis of the cylindrical furnace body, the central channel of the hopper An insulating layer 8 is also set between the rectangular iron core 6 . The other three sides of the iron core are close to the furnace shell wall. The other side of the rectangular iron core 6 is wound with a primary coil 9, and a water cooling jacket 12 (as shown in FIG. 2 ) arranged vertically to the primary coil winding is arranged on the inner side of the primary coil winding; the copper coil 9 of the primary coil is The lead-out end of the winding is led out of the furnace through the insulating sealing device on the furnace body and connected with the power supply device. The high-frequency alternating current applied to the copper winding by the power supply device generates an alternating magnetic field in the iron core, and the alternating magnetic field generates an induced current in the ring iron at the bottom of the hopper, thereby heating the charge.

As shown in Figure 1, an insulating layer 8 is arranged between the furnace body 1 and the hopper 4; an insulating layer 8 is arranged between the rectangular iron core 6 and the hopper 4; then the insulating layer 8, the hopper 4 and the rectangular iron core 6 stitching fixed. Then the furnace shell temperature is only slightly higher than the ambient temperature, so the furnace body is made of ordinary carbon steel. Ordinary carbon steel is the abbreviation of ordinary carbon structural steel, which belongs to low carbon steel, with a carbon content of less than 0.38%, and less than 0.25% is the most commonly used.

The hopper 4 is made of alumina hollow spheres; alumina hollow spheres are a new type of high-temperature heat-insulating material, which are melted and blown from industrial alumina in an electric furnace, and the crystal form is a-Al ₂ O ₃ microcrystals. With alumina hollow spheres as the main body, it can be made into products of various shapes. The maximum service temperature is 1800°C. The product has high mechanical strength, which is several times that of general light products, and its volume density is only half of that of corundum products. It has been widely used in high-temperature and ultra-high-temperature furnaces such as gasifiers in the petrochemical industry, reaction furnaces in the carbon black industry, and induction furnaces in the metallurgical industry, and has achieved very satisfactory energy-saving effects.

The insulation layer 8 is made of ceramic fiber blanket. Ceramic fiber blanket has low thermal conductivity, low heat capacity, excellent chemical stability, excellent thermal stability, and shock resistance, excellent tensile strength, excellent sound absorption, and is an excellent material in thermal insulation and refractory materials.

As shown in FIG. 1 , a feed channel 10 is provided on the top of the furnace body 1 , and the feed channel 10 passes through the insulation layer 8 and communicates with the hopper 4 . The furnace body is an integral structure, and the furnace charge is directly put into the hopper 4 through the feed channel 10. Firstly, the powdery reduction furnace charge is loaded at the bottom of the hopper, and directly contacts the iron and residual slag at the bottom of the hopper, and then the granular or The lumpy charge is put into the upper part of the powdery reduction charge. After the primary side coil on the iron core is energized, the heat generated by the current in the ring iron heats the residual slag and powdery furnace charge through conduction and radiation, and accelerates the heating rate of the furnace charge. When the powdery charge and slag are heated to a molten state, they also have conductivity, and the induced current inside it also generates heat to jointly heat the granular and block charge, and the reduction reaction occurs in two ways: liquid-solid and liquid-liquid . Finally, the charge is completely melted, and the reduction reaction is completed.

As shown in Figure 1, a slag discharge channel 11 is provided at the bottom of the furnace body 1, and the slag discharge channel 11 penetrates the insulation layer 8 and communicates with the bottom of the hopper 4; the slag discharge port is just above the groove 7, and after the reaction is completed, Due to gravity, the molten iron sinks into the groove and will not flow out with the slag, preparing for the next heating.

As shown in FIG. 1 , the upper part of the furnace body is connected to the crystallization chamber 2 through a metal steam channel 5 , an insulating layer 8 is arranged in the metal steam channel 5 , and a coarse suction port 13 is opened on the metal steam channel 5 . A water cooling jacket 15 is provided outside the crystallization chamber 2 , and a fine extraction port 14 is provided on the upper part of the crystallization chamber 2 . In the stage of rough vacuuming, the rough pumping port is used to draw air, so that the dust in the furnace gas will not be deposited in the crystallizer and reduce the purity of crystalline magnesium. When a higher vacuum degree is reached, the gas flow rate is very low at this time, the rough pumping port is closed, and the vacuum is drawn from the fine pumping port passing through the crystallizer. The entire heating element is in a vacuum environment, and the force is very small, and it is not easy to oxidize due to the protection of the vacuum.

The above-mentioned vacuum reduction furnace is mainly used for the production of magnesium, lithium, strontium, calcium and other high vapor pressure metallothermic reduction methods.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model without limitation. Although detailed descriptions have been made with reference to the embodiments of the utility model, those of ordinary skill in the art should understand that the technology of the utility model The modification or equivalent replacement of the scheme does not depart from the spirit and scope of the technical scheme of the present utility model, and all of them shall be covered by the protection scope of the claims of the present utility model.

Claims (5)

1. An electromagnetic induction heating melting reduction metal magnesium vacuum reduction furnace, comprising a furnace body (1), is characterized in that: the furnace body (1) is provided with a hopper (4) made of a hard heat insulating material, the The central part of the hopper (4) is provided with a central channel passing through the bottom surface of the hopper (4); the bottom surface of the hopper (4) is concentrically provided with one or more annular grooves (7), and the grooves (7) Contains iron in solid or molten state; The furnace body (1) is provided with a rectangular iron core (6), one side of the rectangular iron core (6) passes through the central channel of the hopper (4), and the other side of the rectangular iron core (6) The primary side coil (9) is wound; the lead-out end of the copper winding of the primary side coil (9) is led out of the furnace through the insulating sealing device on the furnace body and connected to the power supply device; An insulation layer (8) is provided between the furnace body (1) and the hopper (4); an insulation layer (8) is provided between the rectangular iron core (6) and the hopper (1); the insulation layer (8 ), the hopper (4) and the rectangular iron core (6) are spliced and fixed; The top of the furnace body (1) is provided with a feed channel (10), and the feed channel (10) passes through the insulation layer (8) and communicates with the hopper (4); A slag discharge channel (11) is provided at the bottom of the furnace body (1), and the slag discharge channel (11) penetrates the insulation layer (8) and the hopper (4) and communicates with the bottom of the inner cavity of the hopper (4); The upper part of the furnace body (1) is connected to the crystallization chamber (2) through the metal steam channel (5), the metal steam channel (5) is provided with an insulation layer (8), and the metal steam channel (5) is provided with Coarse pumping port (13); A water-cooling jacket (15) is arranged outside the crystallization chamber (2), and a fine extraction port (14) is arranged on the upper part of the crystallization chamber (2). 2. The electromagnetic induction heating melting reduction metal magnesium vacuum reduction furnace according to claim 1, characterized in that: the inner side of the upper winding of the rectangular iron core (6) is provided with a water cooling jacket vertically arranged with the primary coil (9) (12). 3. The electromagnetic induction heating melting reduction metal magnesium vacuum reduction furnace according to claim 1 or 2, characterized in that the slagging outlet at the bottom of the hopper (4) is just above the groove (7). 4. The electromagnetic induction heating melting reduction metal magnesium vacuum reduction furnace according to claim 3, characterized in that: the cross-sectional shape of the groove (7) is an inverted trapezoid with a long top and a short bottom. 5 . The vacuum reduction furnace for melting and reducing metal magnesium by electromagnetic induction heating according to claim 1 , characterized in that: the top of the furnace body ( 1 ) is provided with a plurality of feeding channels ( 10 ).