CN211921666U - System for continuous magnesium smelting by induction heating liquid state stirring - Google Patents
System for continuous magnesium smelting by induction heating liquid state stirring Download PDFInfo
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- CN211921666U CN211921666U CN202020159684.0U CN202020159684U CN211921666U CN 211921666 U CN211921666 U CN 211921666U CN 202020159684 U CN202020159684 U CN 202020159684U CN 211921666 U CN211921666 U CN 211921666U
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Abstract
The utility model discloses a system for continuous magnesium smelting of liquid stirring of induction heating. The system comprises: the system comprises ferrosilicon, magnesium ore and flux raw material bins, wherein each raw material bin is provided with an inert gas inlet and a vacuum pumping port; a feeding mechanism; the smelting mechanism comprises a closed chamber and an electric induction furnace, the electric induction furnace is arranged in the closed chamber, a feeding pipeline and a flue gas pipeline are arranged at the top of the electric induction furnace, the feeding pipeline extends out of the closed chamber and is connected with the screw conveyor, the flue gas pipeline extends out of the closed chamber, and a slag outlet and an iron outlet are formed in the side part of the electric induction furnace; the induction furnace is also provided with a stirring paddle; inert gas inlets are formed in the side walls of the closed chamber and the induction furnace, and vacuumizing ports are formed in the top wall of the closed chamber and the flue gas pipeline. The system adopts micro negative pressure or normal pressure operation, can realize continuous feeding and discharging, realizes continuous production of magnesium metal, and reduces production cost. Can effectively reduce the content of splashing and smoke dust, improve the quality of the original magnesium and the stable operation condition of the equipment.
Description
Technical Field
The utility model relates to a metallurgical field, particularly, the utility model relates to a system for magnesium is smelted in succession to liquid stirring of induction heating.
Background
At present, the production of most of domestic magnesium metal still adopts the traditional Pidgeon process, and the method at least has the following defects: most procedures in a production field depend on manual operation, so that the labor intensity is high, and the potential safety hazard is high; (2) the magnesium smelting is intermittent production, the reduction period is long, and the production efficiency is low; (3) the production process is fully open, more dust and waste gas are generated on site, the noise is high, and the environmental pollution is serious; (4) the vacuum reduction tank has high price, short service period and large use amount; (5) the reduction smelting adopts an external heating mode, so that the heat utilization efficiency is low; (6) the magnesium reduction reaction is a solid-solid reaction, the reaction rate is slow, and the utilization rate of raw materials is low; (7) reduction smelting needs to be carried out under a vacuum condition, a vacuum system is complex, and the operation energy consumption is high; (8) the reduced magnesium vapor is condensed into solid state at the opening of the tank, has more impurities, needs to be melted and purified again, and has high energy consumption.
The magntherm method of france uses ac electrode heating. Because the electric furnace system is large in volume and insufficient in vacuum degree, the dolomite raw material is directly filled into the furnace, and carbonate in the dolomite undergoes a high-temperature endothermic decomposition reaction, so that the temperature is very high during smelting magnesium by the electric furnace. In addition, the directly-added raw materials are mixed with a ferrosilicon liquid molten pool only by melt heat convection, the reaction rate in the molten pool is slow, the temperature and components are uneven, and a flow field dead zone is easy to form, so that the utilization rate of the raw materials and the reducing agent is low, and the smelting period is long. The whole production cycle is reported to be 16-24 hours, 3-8 t of metal magnesium can be produced in one day, 7t of magnesium raw material is consumed per ton, and the production efficiency is low.
In the technical process of patent CN103882246A, ferrosilicon needs to be melted in a smelting furnace and then poured into a ferrosilicon ladle in a vacuum reduction chamber. Because a heating device is not arranged in the vacuum chamber, magnesium reduction and metal magnesium evaporation are both endothermic reactions, and in addition, magnesium ore powder needs to be blown into ferrosilicon liquid, the temperature of a fused mass in the ferrosilicon bag is easily and rapidly reduced, the viscosity of the fused mass is increased, the reduction reaction rate is reduced, and magnesium vapor is easily condensed in a pipeline due to insufficient overheating. Even if the heating mode is adopted in the blowing process as shown in CN105970004A, CN105950889A and CN107541608A, a large amount of heat can be taken away from the melt due to the excessive amount of the injected gas, and the thermal efficiency of the device is reduced. And the blowing also can generate a large amount of smoke dust to pollute a device and a smoke system, reduce the purity of the metal crude magnesium and increase the burden of subsequent smoke treatment and magnesium refining. In addition, the magnesium-containing raw materials such as calcined dolomite need to be ground to be fine, are easy to absorb water and deliquesce, block a material pipe, and are not easy to produce stably. Moreover, most techniques require maintaining a vacuum environment in the system, increasing the burden on the system, and thus increasing energy consumption and cost.
In summary, the existing magnesium smelting systems still need to be improved.
SUMMERY OF THE UTILITY MODEL
The present invention aims at solving at least one of the technical problems in the related art to a certain extent. Therefore, the utility model discloses an aim at propose the system of the continuous magnesium metallurgy of induction heating liquid stirring. The system adopts micro negative pressure or normal pressure operation, the load of the vacuum system is small, and the energy and power consumption is low. Short technological process, less equipment investment and high automation degree. The reduction reaction rate is high, the production efficiency is high, and the metal recovery rate is high. Can realize continuous feeding and discharging, realize continuous production of magnesium metal and reduce production cost. Can effectively reduce the content of splashing and smoke dust, improve the quality of the original magnesium and the stable operation condition of the equipment.
In one aspect of the present invention, the present invention provides a system for continuous magnesium smelting by liquid stirring with induction heating. According to the utility model discloses an embodiment, this system of continuous magnesium smelting of liquid stirring of induction heating includes:
the device comprises a ferrosilicon bin, a magnesium ore bin and a flux bin, wherein the ferrosilicon bin, the magnesium ore bin and the flux bin are all provided with a material outlet, an inert gas inlet and a vacuumizing port;
the feeding mechanism comprises a quantitative feeder and a screw conveyor, the quantitative feeder is connected with the material outlet, and the screw conveyor is provided with an inert gas inlet;
the smelting mechanism comprises a closed chamber and an electric induction furnace, the electric induction furnace is arranged in the closed chamber, a feeding pipeline and a flue gas pipeline are arranged at the top of the electric induction furnace, the feeding pipeline extends out of the closed chamber and is connected with the screw conveyor, the flue gas pipeline extends out of the closed chamber, a slag hole and an iron outlet are formed in the side part of the electric induction furnace, and the slag hole and the iron outlet extend out of the closed chamber in a siphoning type removing mode; the induction furnace is also provided with a stirring paddle, and the stirring paddle extends into the induction furnace from the top of the induction furnace; the side walls of the closed chamber and the induction furnace are provided with inert gas inlets, and the top wall of the closed chamber and the flue gas pipeline are provided with vacuumizing ports.
Adopt according to the utility model discloses system smelting magnesium of liquid stirring continuous magnesium of induction heating is at first discharged the air in equipment through the evacuation mouth that is located on each feed bin and sealed chamber, induction furnace to fill into inert gas through the inert gas import, be in ordinary pressure or little negative pressure state in making equipment. Then the ferrosilicon alloy is fed into the hearth of the induction furnace through the feeding mechanism, and is heated to melt the ferrosilicon alloy, so that a molten pool is formed in the hearth of the induction furnace. And subsequently, vertically lowering the stirring paddle into the molten pool, and continuously rotating the molten pool under the action of the stirring paddle to form vortex in the central area of the melt surface close to the paddle rod of the stirring paddle. And then, adding the magnesium ore and the flux into a molten pool after metering, and enabling the fed materials to vertically fall into a point close to a stirring area. The magnesium ore and the flux enter the molten pool under the entrainment action of the vortex of the molten pool, and carry out magnesium reduction reaction with silicon element in the molten pool to obtain magnesium vapor, silicon-containing molten iron and molten slag. Along with the reaction, the silicon content in the molten pool is gradually reduced, and the ferrosilicon alloy, the magnesium ore and the flux can be continuously added into the molten pool, so that the continuous production of the magnesium metal is realized. Therefore, the system is operated under micro negative pressure or normal pressure, does not need vacuum or operates under low vacuum condition, and has small burden of a vacuum system and low energy and power consumption. Short technological process, less equipment investment and high automation degree. The reduction reaction rate is high, the production efficiency is high, and the metal recovery rate is high. Can realize continuous feeding and discharging, realize continuous production of magnesium metal and reduce production cost. Can effectively reduce the content of splashing and smoke dust, improve the quality of the original magnesium and the stable operation condition of the equipment.
Optionally, the ferrosilicon silo, the magnesium ore silo and the flux silo all comprise an upper silo and a lower silo.
Optionally, valves are provided between the upper bin and the lower bin, and between the lower bin and the doser.
Optionally, the inert gas inlet located on the side wall of the induction furnace comprises a plurality of inert gas inlets, and the inert gas inlets are symmetrically arranged at the center of the induction furnace.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic structural view of a magnesium smelting system according to an embodiment of the present invention;
FIG. 2 is a schematic view of a stirring paddle stir bath in a magnesium smelting system according to one embodiment of the present invention;
FIG. 3 is a schematic diagram of the relative position relationship between the raw material feeding position and other regions in the magnesium smelting system according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In one aspect of the present invention, the present invention provides a system for continuous magnesium smelting by liquid stirring with induction heating. According to the embodiment of the utility model, referring to fig. 1, this system of continuous magnesium smelting of induction heating liquid stirring includes:
a material bin, the material bin includes: the ferrosilicon bin 110, the magnesium ore bin 120 and the flux bin 130 are all provided with a material outlet (not shown in the attached drawing), an inert gas inlet 10 and a vacuum pumping port 20;
the feeding mechanism comprises a quantitative feeder 210 and a spiral conveyor 220, the quantitative feeder 210 is connected with the material outlet of each material bin, and the spiral conveyor 220 is provided with an inert gas inlet 10;
the smelting mechanism comprises a closed chamber 310 and an electric induction furnace 320, wherein the electric induction furnace 320 is arranged in the closed chamber 310, a feeding pipeline 321 and a flue gas pipeline 322 are arranged at the top of the electric induction furnace 320, the feeding pipeline 321 extends out of the closed chamber 310 and is connected with the screw conveyor 220, the flue gas pipeline 322 extends out of the closed chamber 310, a slag outlet 323 and an iron outlet 324 are arranged at the side part of the electric induction furnace 320, and the slag outlet 323 and the iron outlet 324 extend out of the closed chamber 310 in a siphon type discharge mode; the induction furnace 320 is also provided with a stirring paddle 325, and the stirring paddle 325 extends into the induction furnace 320 from the top of the induction furnace 320; wherein, the side walls of the closed chamber 310 and the induction furnace 320 are provided with inert gas inlets 10, and the top wall of the closed chamber 310 and the flue gas pipeline 322 are provided with vacuum pumping ports 20.
Specifically, the inert gas inlet 10 and the vacuum pumping port 20 can be connected to an external inert gas source or a vacuum pumping device through corresponding pipes.
The system for continuous magnesium smelting by induction heating and liquid stirring according to the embodiment of the invention is further described in detail below.
According to the embodiment of the present invention, the silicon iron bin 110, the magnesium ore bin 120, the flux bin 130, the silicon iron bin 110, the magnesium ore bin 120, and the flux bin 130 all have a material outlet (not shown in the drawings), an inert gas inlet 10, and a vacuum pumping port 20. Particularly, the ferrosilicon bin, the magnesium ore bin and the flux bin are respectively suitable for storing ferrosilicon, magnesium ore and flux, and each bin is provided with an inert gas inlet and a vacuum pumping port so as to control the overall atmosphere and air pressure of each bin and the magnesium smelting system.
According to the utility model discloses an embodiment, ferrosilicon feed bin 110, magnesium ore feed bin 120, flux feed bin 130 all include feed bin and lower feed bin. That is, each storage bin adopts upper and lower two storehouses to material gas is sealed.
According to the utility model discloses an embodiment, each material storehouse go up the feed bin with all be equipped with valve 30 between the feed bin and between lower feed bin and the doser 210. Therefore, the atmosphere and the air pressure between the upper and lower storage bins can be conveniently controlled, and the feeding amount of each material can be conveniently controlled.
According to an embodiment of the present invention, the silicon content in the above-mentioned ferrosilicon is not less than 75 wt%, preferably 75 ferrosilicon alloy. Therefore, the ferrosilicon raw material has a low melting point and a high silicon content, and can effectively improve the efficiency of reduction reaction and the recovery rate of magnesium metal. In addition, it should be noted that, silicon-manganese alloy or low melting point alloy composed of silicon and other heavy metals may also be used as the reducing agent for smelting magnesium, but the effect is relatively poor compared with that of iron alloy, and will not be described herein again.
According to the utility model discloses an embodiment, above-mentioned magnesium ore can include at least one of selecting from among dolomite and magnesite, and the source of this type of magnesium ore is extensive, and magnesium content is higher, and through carrying out reduction smelting with ferrosilicon, the rate of recovery of magnesium metal is high. In addition, the magnesium ore can be calcined or not calcined before use, and the calcined magnesium ore has better reactivity in smelting.
According to an embodiment of the present invention, the flux may include at least one selected from fluorite, potassium fluoride and sodium fluoride. By using the flux, the reduction effect of the magnesium ore can be further improved.
According to the utility model discloses an embodiment, above-mentioned ferrosilicon, magnesium ore and flux pass through crushing treatment in advance before putting into corresponding feed bin. Specifically, according to an embodiment of the present invention, the ferrosilicon may have an average particle size of 2 to 30mm (e.g., 2mm, 10mm, 20mm, 30mm, etc.), the magnesium ore may have an average particle size of 5 to 50mm (e.g., 5mm, 10mm, 20mm, etc.), and the flux may have an average particle size of 3 to 50mm (e.g., 5mm, 10mm, 20mm, 40mm, etc.). By controlling the particle size of each material within the above range, the reduction reaction can be further facilitated.
According to the utility model discloses an embodiment, feed mechanism includes doser 210 and screw conveyer 220, and doser 210 links to each other with the material export of each material feed bin, is equipped with inert gas import 10 on the screw conveyer 220. The doser 210 is adapted to take material from each bin and feed the material into the induction furnace 320 using the screw conveyor 220. The screw conveyer 220 is provided with an inert gas inlet 10, and inert gas can be filled into the system through the inert gas inlet 10 after the system is vacuumized, so as to assist in controlling the atmosphere and the air pressure in the system.
According to the embodiment of the present invention, the closed chamber 310 of the melting mechanism and the induction furnace 320 are adapted to perform reduction treatment of magnesium ore using ferrosilicon and flux so as to obtain magnesium vapor, molten iron containing silicon, and molten slag.
Specifically, the induction furnace 320 is disposed within the enclosed chamber 310 to facilitate control of the atmosphere and pressure within the induction furnace 320. Before smelting, the sealed chamber 310 and the induction furnace 320 are first evacuated, and then an inert gas (e.g., argon or the like) is filled into the sealed chamber 310 and the induction furnace 320 so that the gas pressure in the sealed chamber 310 and the induction furnace 320 reaches a predetermined range. Subsequently, ferrosilicon is added to the induction furnace 320. In some embodiments of the present invention, the induction furnace lining is comprised of a graphite refractory 326 and has a magnesium refractory formed on its surface. The graphite refractory material generates induction heat under the action of an induction electromagnetic field, and the ferrosilicon is heated to form a molten pool. And then, vertically lowering the stirring paddle into the molten pool, continuously rotating the molten pool under the action of the stirring paddle, forming a vortex in a central area of the surface of the melt, which is close to a stirring paddle rod (as shown in figure 2), then adding the magnesium ore and the flux into the molten pool after metering, and enabling the feeding point to vertically drop to be close to the stirring area (as shown in figure 3). Magnesium ore and flux enter the molten pool under the entrainment action of the vortex of the molten pool, and carry out magnesium reduction reaction with silicon element in the molten pool, the magnesium metal obtained by reduction escapes from the molten pool in the form of magnesium vapor after being heated, enters into gas phase, and is discharged from a flue gas pipeline along with the flow of inert gas or under the action of vacuum pumping, and the subsequent magnesium vapor can be collected by condensation to obtain liquid crude magnesium or magnesium ingots. The silicon dioxide generated by reducing magnesium reacts with flux, calcium oxide in magnesium ore and the like to generate slag, after the slag accumulates for a certain depth in the furnace, the slag outlet is opened, and the slag is discharged under the siphon action, so that the slag can be sold for producing building materials and the like.
According to the embodiment of the present invention, the reactions mainly involved in the above reduction reaction include:
2MgO(s)+Si(Fe)(l)＝2Mg(g)+SiO2(s)
SiO2(s)+2CaO(s)＝2CaO·SiO2(l)
further, along with the reduction reaction, the silicon content in the molten pool is gradually reduced, the silicon iron can be continuously added into the induction furnace, after the silicon-containing molten iron accumulated in the molten pool reaches a certain depth, the iron outlet on the side part of the furnace body is opened to discharge and collect the silicon-containing molten iron, and the silicon-containing molten iron can be sold as low-silicon iron alloy or can be smelted into high-silicon iron alloy again to return to magnesium smelting. In addition, according to the utility model discloses a preferred embodiment, in the induction electric furnace, keep the interior ferrosilicon liquid that contains about 10 ~ 20% furnace degree of depth of stove as the molten bath throughout. Therefore, the magnesium alloy can accelerate the melting speed of solid raw materials such as magnesium ore, flux and the like, improve the heating efficiency and the heating speed of the induction furnace, can also be used as a high-temperature catalyst and a heat storage molten pool, and promotes the magnesium reduction speed, thereby improving the production speed.
According to the utility model discloses an embodiment, at the initial stage of smelting, the ferrosilicon volume that adds in to induction furnace uses the degree of depth of ferrosilicon formed molten bath to be suitable for 20 ~ 50% of induction furnace degree of depth, and further preferred is 30 ~ 40%.
According to the utility model discloses an embodiment, in the stage of submerging the stirring rake into the molten bath, the preferred submergence volume that makes stirring rake oar head part is 70 ~ 90%, stirs the molten bath from this, can the fuse-element under the stirring effect of stirring rake, and inside production axial flow and radial flow (as shown in figure 3) promote the solid raw materials of adding to be drawn into inside the molten bath fast and react with the ferrosilicon, reduce the inhomogeneity of molten bath temperature and chemical composition to the magnesium vapour that the help will reduce the production takes out from the molten bath, improves reaction rate.
According to the utility model discloses an embodiment, in fig. 3, 1 is the raw materials whereabouts region, and 2 is the stirring region, and 3 is the molten bath region, and 4 is the flue outlet projection. By controlling the falling area of the raw materials to be close to the stirring area, the magnesium ore and the flux can further enter the molten pool under the entrainment action of the vortex of the molten pool, and the magnesium reduction reaction is carried out on the magnesium ore and the flux and silicon element in the molten pool.
According to an embodiment of the present invention, referring to fig. 3, the inert gas inlet 10 located at the side wall of the induction furnace 320 includes a plurality of inert gas inlets arranged in a central symmetry of the induction furnace. Therefore, the atmosphere and the gas pressure in the induction furnace can be further favorably controlled.
In addition, according to the embodiment of the present invention, the induction furnace is also suitable for smelting magnesium under vacuum condition. Specifically, after the sealed chamber and the induction furnace are vacuumized, the vacuum magnesium smelting can be carried out by pumping the sealed chamber and the induction furnace into low vacuum without filling inert gas into the furnace. Therefore, the utility model provides a system has the function of ordinary pressure smelting magnesium and vacuum smelting magnesium simultaneously.
For convenience of understanding, the magnesium smelting method carried out by using the magnesium smelting system of the above embodiment will be described below. According to the utility model discloses an embodiment, this method includes: (1) vacuumizing the magnesium smelting system by using a vacuumizing device, and filling inert gas into the magnesium smelting system; feeding ferrosilicon into an induction furnace and melting by heating to form a molten pool; (2) stirring the molten pool by using a stirring paddle, and adding magnesium ore and a flux to perform a reduction reaction so as to obtain magnesium vapor, silicon-containing molten iron and molten slag; and (3) supplementing ferrosilicon, magnesium ore and flux into the molten pool according to the reaction progress of the reduction reaction.
According to a specific example of the present invention, the above magnesium smelting method comprises:
(1) firstly, crushing ferrosilicon with Si content not less than 75% into blocks with particle size of 2-30 mm. And crushing and screening the flux into particles with the particle size of 5-50 mm. And crushing the magnesium-containing ore into blocks with the particle size of 5-50 mm. All raw materials are put into the corresponding material bins, the raw material bins are sealed in an up-down double-bin mode, and the material bins are simultaneously provided with pipelines for exhausting and filling argon so as to discharge air in the bins in time and fill argon to stabilize the air pressure in the bins.
The magnesium-containing ore can be one or more of raw materials such as non-calcined or calcined dolomite, magnesite and the like.
The flux may be one or more of fluorite, potassium fluoride, sodium fluoride and the like.
Besides the 75 Si-Fe alloy, there is also Si-Mn or a low-melting point alloy of Si and other metals as a magnesium reducing agent.
(2) In an induction electric furnace, firstly, ferrosilicon is heated and melted into liquid state, and the temperature of the ferrosilicon liquid is controlled to be 1450-1650 ℃. The inner lining of the induction furnace is made of graphite refractory material, and the outer layer of the induction furnace is made of magnesium refractory material. The graphite refractory material generates induction heat under the action of an induction electromagnetic field, ferrosilicon in the melting furnace is heated, a liquid molten pool is formed in the furnace, and the molten pool accounts for about 20-50% of the capacity of the induction furnace.
(3) The whole induction heating furnace body adopts a sealed design, a sealed chamber is arranged outside the induction heating furnace body, and the sealed chamber and the induction heating furnace are both provided with a vacuumizing and argon gas charging pipeline. Wherein, the argon gas filling hole of the furnace body is arranged at the upper part of the side surface of the furnace body, and 2 argon gas filling holes are arranged oppositely. During the heating operation of the furnace body, argon gas flow can be simultaneously filled into the closed chamber and the furnace body to produce inert atmosphere for magnesium smelting. At this time, the atmospheric pressure in the closed chamber is slightly greater than the atmospheric pressure in the induction furnace.
In addition, except for the magnesium smelting process by continuously filling argon gas into the furnace and the closed chamber to maintain the normal pressure or micro negative pressure level in the furnace, vacuum magnesium smelting can be carried out by closing the argon gas and simultaneously pumping the furnace body and the closed chamber into low vacuum. Therefore, the device can have the functions of normal pressure and vacuum smelting at the same time.
(4) After a ferrosilicon alloy molten pool is formed in the furnace, a mechanical stirring paddle is vertically lowered into the alloy molten pool, and the immersion amount of a paddle head accounts for about 70-90%. Then, the stirring paddle is started, the molten pool is continuously rotated under the action of the stirring paddle, and eddy current is formed on the surface of the melt in the central area close to the paddle rod. At the moment, raw materials such as magnesium ore, flux and the like are added into a molten pool in the furnace under the action of a screw conveyor, and the feeding materials vertically fall into a point close to a stirring area. The solid raw material is brought into the alloy molten pool under the entrainment action of the molten pool vortex and generates magnesium reduction reaction with Si element in the molten pool.
(5) MgO in the magnesium ore and Si in the ferrosilicon liquid are subjected to reduction reaction to generate metal Mg, the metal Mg is gasified by heating, escapes from the melt, enters a gas phase, is discharged from a pipeline along with argon flow or under the action of vacuumizing, and is condensed and collected to obtain liquid crude magnesium or magnesium ingots. SiO produced by magnesium reduction2Reacting with CaO, flux and the like in the ore to generate slag, and accumulating the slag to a certain depth in the furnaceAnd opening a slag outlet, discharging the slag into a slag basin under the action of siphon, and selling the reducing slag for producing building materials. The reduction reaction comprises the following steps:
2MgO(s)+Si(Fe)(l)＝2Mg(g)+SiO2(s)
SiO2(s)+2CaO(s)＝2CaO·SiO2(l)
(6) and when the content of Si in the reducing agent molten pool is reduced, the ferrosilicon alloy can be continuously added into the furnace, and after the silicon-poor molten iron accumulated in the molten pool reaches a certain depth, a tapping hole on the side surface of the furnace body is opened to discharge the silicon-poor molten iron to the ladle. The silicon-poor molten iron can be sold as low-silicon iron alloy, and can also be smelted into high-silicon iron alloy again to be returned to magnesium smelting.
(7) In the induction furnace, the ferrosilicon liquid with the furnace depth of 20-30% is always kept in the furnace to serve as a reaction molten pool, so that the melting speed of solid raw materials can be increased, the heating efficiency and the heating speed of the induction furnace are improved, the ferrosilicon liquid can also serve as a high-temperature catalyst and a heat storage molten pool, the magnesium reduction speed is promoted, and the production speed is further improved.
Through paddle shape for the stirring of reasonable in design, quantity, angle, size isoparametric, can make the fuse-element under stirring effect, inside production axial flow and radial flow promote the solid raw materials that add to be drawn into the molten bath fast inside and react with silicon iron liquid, reduce the inhomogeneity of molten bath temperature and chemical composition, the magnesium vapour that will reduce the production at last takes out from the molten bath, improves reaction rate.
As mentioned above, the magnesium smelting process proposed by the present invention may have at least one of the following advantages:
(1) a reducing agent molten pool is built in the induction furnace, and a mechanical propeller stirring mode is adopted, so that the stirring of the melt and the solid raw materials in the furnace is realized, the reaction process is accelerated, and the homogenization of the materials and the temperature in the melt is promoted;
(2) the magnesium-containing raw material, the flux and the metal reducing agent are added to a melting pool in the furnace in a spiral feeding mode and are brought into the melt to participate in the reduction reaction under the vortex entrainment effect formed by spiral stirring.
(3) The induction heating mode is adopted, and the heat is generated and transferred by the graphite refractory material.
(4) Each raw material bin adopts vertical double-bin arrangement, and each bin is provided with an inert gas filling and vacuumizing pipeline to ensure that no air enters the bin.
(5) The heating furnace body of the induction furnace is positioned in the closed chamber, and the electric furnace and the closed chamber are both provided with vacuum pumping and inert gas injection ports, so that double-layer atmosphere protection is realized.
(7) The production process can be carried out under the normal pressure atmosphere formed by inert gas flow, and can also be directly carried out under the vacuum condition.
The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way.
Example 1
The calcined dolomite is directly crushed into blocks with the grain size of 20-40 mm, the 75-silicon-iron alloy is crushed into blocks with the grain size of 5-25 mm, and the flux fluorite is crushed into blocks with the grain size of 10-30 mm, and the blocks are respectively loaded into a storage bin.
Pumping the induction furnace, the closed chamber and the subsequent system to a vacuum degree of 1000Pa, closing the vacuum system, opening the argon gas charging system, introducing argon gas into the induction furnace and the closed chamber, closing the argon gas system and opening the vacuum system after the gas pressure in the induction furnace reaches the normal pressure of 0.1 MPa. Repeating the above steps for 2 times to fully exhaust residual air in the induction furnace, the sealed chamber and the subsequent system. And finally, continuously introducing argon flow into the furnace, and maintaining the gas pressure in the furnace at 0.1-0.12 MPa and the pressure in the closed chamber at 0.11-0.13 MPa.
In the exhaust process of the system, ferrosilicon is added into the induction furnace, the induction furnace is electrified and heated, the temperature of the ferrosilicon in the induction furnace is gradually raised, the ferrosilicon in the induction furnace is gradually melted into liquid after reaching 1500 ℃, a reducing agent molten pool is formed in the induction furnace, and the depth of the molten pool is about 40 percent of the depth of a hearth.
And after a molten pool in the furnace is formed, lowering a stirring paddle into the molten pool, opening a dolomite and fluorite bin valve, weighing according to the mass ratio of 100:3 of dolomite to fluorite, conveying to a feeding pipe opening under the drive of a screw conveyor, and dropping into the molten pool in the furnace. The solid raw material is violently mixed with the ferrosilicon reducing agent under the action of vortex entrainment on the surface of the molten pool to generate magnesium reduction reaction.
After the magnesium metal vapor is reduced, the magnesium metal vapor enters a subsequent condensing system for collection through a flue under the drive of argon flow in the furnace to obtain magnesium metal liquid. When the MgO content in the slag reaches below 10%, the feeding valve is opened to continuously feed the raw materials into the furnace, so that the aim of continuous feeding is fulfilled.
And after the slag in the furnace is accumulated to 70-80% of the depth in the furnace, stopping stirring, opening a slag outlet, and discharging the slag in the furnace to a slag ladle outside the furnace under the siphoning action. According to calculation, after the content of Si in the silicon-poor molten iron in the furnace is reduced to below 20% and the furnace capacity is accumulated to 40-50%, opening a tapping hole, discharging the silicon-poor molten iron to a molten iron ladle outside the furnace under the siphoning effect, and still maintaining a molten iron pool which accounts for about 10-20% of the furnace capacity in the furnace.
Example 2
The dolomite is directly crushed into blocks with the grain size of 20-40 mm, the 75 silicon-iron alloy is crushed into blocks with the grain size of 5-25 mm, and the flux fluorite is crushed into blocks with the grain size of 10-30 mm, and the blocks are respectively loaded into a storage bin.
And pumping the induction furnace, the closed chamber and the subsequent system to a vacuum degree of 800-1000 Pa. Adding ferrosilicon into the induction furnace, electrifying and heating, gradually raising the temperature of the ferrosilicon in the induction furnace, gradually melting the ferrosilicon into liquid after reaching 1500 ℃, forming a reducing agent molten pool in the induction furnace, wherein the depth of the molten pool is about 40% of the depth of the hearth.
And after a molten pool in the furnace is formed, lowering a stirring paddle into the molten pool, opening a dolomite and fluorite bin valve, weighing according to the mass ratio of 100:3 of dolomite to fluorite, conveying to a feeding pipe opening under the drive of a screw conveyor, and dropping into the molten pool in the furnace. The solid raw material is violently mixed with the ferrosilicon reducing agent under the action of vortex entrainment on the surface of the molten pool to generate magnesium reduction reaction.
After the magnesium metal vapor is reduced, the magnesium metal vapor enters a subsequent condensing system for collection through a flue under the drive of argon flow in the furnace to obtain magnesium metal liquid. When the MgO content in the slag reaches below 10%, the feeding valve is opened to continuously feed the raw materials into the furnace, so that the aim of continuous feeding is fulfilled.
And after the slag in the furnace is accumulated to 70-80% of the depth in the furnace, stopping stirring, opening a slag outlet, and discharging the slag in the furnace to a slag ladle outside the furnace under the siphoning action. According to calculation, after the content of Si in the silicon-poor molten iron in the furnace is reduced to below 20% and the furnace capacity is accumulated to 40-50%, opening a tapping hole, discharging the silicon-poor molten iron to a molten iron ladle outside the furnace under the siphoning effect, and still maintaining a molten iron pool which accounts for about 10-20% of the furnace capacity in the furnace.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the scope of the present invention.
Claims (4)
1. A system for continuously smelting magnesium by induction heating and liquid stirring, which is characterized by comprising:
the device comprises a ferrosilicon bin, a magnesium ore bin and a flux bin, wherein the ferrosilicon bin, the magnesium ore bin and the flux bin are all provided with a material outlet, an inert gas inlet and a vacuumizing port;
the feeding mechanism comprises a quantitative feeder and a screw conveyor, the quantitative feeder is connected with the material outlet, and the screw conveyor is provided with an inert gas inlet;
the smelting mechanism comprises a closed chamber and an electric induction furnace, the electric induction furnace is arranged in the closed chamber, a feeding pipeline and a flue gas pipeline are arranged at the top of the electric induction furnace, the feeding pipeline extends out of the closed chamber and is connected with the spiral conveyor, the flue gas pipeline extends out of the closed chamber, a slag hole and an iron outlet are formed in the side part of the electric induction furnace, and the slag hole and the iron outlet extend out of the closed chamber; the induction furnace is also provided with a stirring paddle, and the stirring paddle extends into the induction furnace from the top of the induction furnace; the side walls of the closed chamber and the induction furnace are provided with inert gas inlets, and the top wall of the closed chamber and the flue gas pipeline are provided with vacuumizing ports.
2. The system for induction heating liquid stirring continuous magnesium smelting according to claim 1, wherein the ferrosilicon bin, the magnesium ore bin and the flux bin each include an upper bin and a lower bin.
3. The system for induction heating liquid stirring continuous magnesium smelting according to claim 2, wherein valves are provided between the upper bin and the lower bin, and between the lower bin and the dosers.
4. The system for liquid stirring continuous magnesium smelting through induction heating according to claim 1, wherein the inert gas inlets provided on the side wall of the induction furnace comprise a plurality of inert gas inlets, and the plurality of inert gas inlets are symmetrically arranged around the center of the induction furnace.
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| CN111270088A (en) * | 2020-02-10 | 2020-06-12 | 中国恩菲工程技术有限公司 | System and method for continuously smelting magnesium by induction heating liquid stirring |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111270088A (en) * | 2020-02-10 | 2020-06-12 | 中国恩菲工程技术有限公司 | System and method for continuously smelting magnesium by induction heating liquid stirring |
| CN111270088B (en) * | 2020-02-10 | 2023-10-13 | 中国恩菲工程技术有限公司 | System and method for continuously smelting magnesium by liquid stirring through induction heating |
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