Magnesium metallurgy device and method through negative pressure atomization and supergravity enhanced liquid-solid reaction

Abstract

The invention discloses a negative pressure atomization and supergravity enhanced liquid-solid reaction magnesium metallurgy device and method.The device comprises a furnace body, a liquid-solid mixing reaction material tank, a first-stage material gathering taper pipe and a second-stage material gathering taper pipe are fixedly arranged in the furnace body from top to bottom, and a solid raw material distributing plate is fixedly arranged in the liquid-solid mixing reaction material tank; powder feeding threads are formed in the solid raw material feeding pipe, the solid raw material feeding pipe is rotationally connected with the furnace body and connected with a transmission assembly, the solid raw material feeding pipe is rotationally connected with a neck of a hopper, and the neck of the hopper is connected with a solid raw material feeding vacuum valve; a liquid reducing agent sprayer fixedly connected with a liquid reducing agent feeding pipe is arranged in the liquid-solid mixing reaction material tank, and the liquid reducing agent feeding pipe is rotationally connected with the liquid-solid mixing reaction material tank and is connected with a liquid reducing agent feeding vacuum valve; the solid raw material feeding pipe and the liquid reducing agent feeding pipe are both provided with heating rings, the furnace body is connected with the magnesium steam collecting system connected with the vacuumizing system, the slag outlet capable of being sealed is formed in the bottom of the furnace body, energy consumption of magnesium metallurgy is reduced, and the reaction efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of magnesium metallurgy, and in particular relates to a negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy device and method. Background Art

[0002] Magnesium metallurgical technology mainly includes electrolysis and Pidgeon process. In the last century, due to the high cost of raw materials, the electrolysis method was mainly used internationally. In this century, due to the advantages of small investment, simple process and convenient operation, the Pidgeon process has developed rapidly in my country's primary magnesium industry. More than 90% of my country's primary magnesium is produced by the Pidgeon process.

[0003] The Pidgeon process was developed in 1941 by L.M. Pidgeon, a professor at the University of Toronto in Canada. It involves grinding calcined dolomite, ferrosilicon and fluorite into powder and pelletizing them in proportion, and adding the pellets into a reduction tank made of heat-resistant alloy steel. The temperature in the reduction tank is maintained at 1150-1200°C and the vacuum degree is about 10-20Pa. A reduction reaction occurs at high temperature, and the generated magnesium vapor flows to a cooling zone with a crystallization water jacket and condenses into crystalline magnesium. Professor Pidgeon applied this process to establish an experimental device in Ottawa for reducing calcined dolomite using ferrosilicon as a reducing agent. The following year, the world's first Pidgeon process magnesium smelting plant with an annual output of 5,000 tons was built in Haley, Ontario, Canada.

[0004] The traditional Pidgeon magnesium metallurgical process first adopted horizontal tube reduction, which mainly includes three major processes, called the "three-step" magnesium smelting process, including dolomite calcination, ball reduction and crude magnesium refining, from dolomite calcination to batching, grinding, ball making, and then to high-temperature vacuum reduction, and finally crude magnesium refining and ingot casting to become commercial magnesium. Although horizontal tubes are widely used, they belong to multi-tube intermittent continuous production, and the working and thermal efficiency are not high. With the need for continuous magnesium reduction, vertical tube reduction has gradually emerged. The concept of vertical tanks is the same as that of horizontal tubes, using the same raw materials and preparation processes, the same temperature and vacuum, and both use external heating methods and heat-resistant steel alloy tanks. The difference is that the reduction tank is installed vertically, and there are upper feeding and upper slag discharge modes and upper feeding and lower slag discharge modes.

[0005] In recent years, the development of vertical tanks is almost all the transformation and upgrading of horizontal tanks. The reaction principle remains unchanged, but more of the tank and furnace structure and production process are upgraded. The whole reduction tank is basically divided into three working areas: crystallization section, reaction section and slag discharge section. The reduction tank has a built-in porous central tube for the circulation of magnesium vapor, which flows to the crystallization area and condenses into crystalline magnesium. The crystalline magnesium is taken out from the upper tank port, and the reduction slag is discharged from the lower tank port. The reduction furnace uses a regenerative combustion system, which is generally designed to burn up and down, that is, burn up and exhaust smoke at the bottom, or burn down and exhaust smoke at the top. Although this vertical tank process with upper loading and upper slag discharge has a shorter reduction time than the horizontal tube type, it needs a suspension device to lift the reduction tank under high temperature environment. The operating environment is harsh, and magnesium is easily oxidized, with a short life and poor reliability.

[0006] The existing Pijiang magnesium smelting technology, whether it is horizontal tank reduction or vertical tank reduction, has the following major problems: First, high energy consumption and large carbon emissions. The heat source for external heating in my country's Pijiang process is basically the heat generated by liquid fuel, gas fuel and solid fuel. Among them, most magnesium plants use solid coal as fuel. It consumes 8 to 12 tons of high-quality coal to produce one ton of magnesium. Its energy consumption is high and CO2 emissions are large, which cannot meet the requirements of the new national energy consumption and emission standards; second, it takes a long time and has low efficiency. The horizontal tube reduction time is as high as about 11 hours. Even if internal and external heating is adopted, it still takes more than 5 hours, which is inefficient; third, the intermittent production method cannot be realized due to the limited tank volume. Continuous, although some vertical tube types have achieved continuity, but the stability is poor and has not yet become the mainstream of industrial application; fourth, the reduction rate is low. Due to the solid-solid reduction in magnesium metallurgy, the reduction rate is relatively low. The reaction is restricted by mass transfer and heat transfer efficiency. The reduction rate of calcined dolomite is only about 85%, and it is very difficult to increase it further, thus causing greater waste of resources and energy; fifth, the heat transfer method is single and the heat transfer efficiency is low. First, since calcined dolomite itself is a poor thermal conductor and the sample is in a systematic vacuum environment, there is no convection mechanism for heat transfer, which significantly reduces the efficiency of heat conduction and thermal radiation; secondly, thermal radiation heat transfer has the characteristics of surface heat transfer. The larger the direct irradiation area, the better the heat transfer effect. However, since the pellets themselves are restricted by the pile state during the preparation process, the outer surface of the pellet pile is mainly radiative heat transfer, and the inside is mainly conductive mechanism; thirdly, whether it is between the pellets in the pile or between the powder particles inside the pellets, point contact is mainly used, and the contact surface of the heat conduction mechanism is small, which significantly reduces the heat transfer efficiency between the pellets inside the pile and between the particles inside the pellets.

[0007] Although both vertical tank reduction and horizontal tank reduction have many disadvantages, given that vertical tank reduction has better performance, people's focus is generally on how to improve the thermal efficiency of vertical tank reduction. For this reason, many people in the industry have made relevant research and designs. For example: Professor Wang Xiaogang's team from Xi'an University of Science and Technology proposed the idea of ​​internal and external heating and won the second prize of the National Technological Progress Award; Professor Zhang Ting'an's team from the Metallurgical Department of Northeastern University proposed a method of continuous calcination of dolomite and magnesium reduction, which achieved continuous calcination of dolomite and magnesium reduction, and achieved the goal of reducing energy consumption through the coordination of energy forward and backward; Che Yusi's team from Zhengzhou University used argon enhanced convection to significantly improve the heating efficiency of pellets, but due to the small hot melt of argon, the enhanced heat transfer effect is difficult to further improve, which in turn limits its industrial application.

[0008] Although the above research has made some improvements in reducing the problem of high energy consumption in magnesium metallurgy, it has not completely solved the problem of high energy consumption in magnesium metallurgy. The main reason is that in a systematic vacuum environment, there is no convective heat transfer, and it can only rely on heat conduction and thermal radiation. The effect of heat conduction depends on the conductivity of the material, and the effect of radiation heat transfer depends on the area of ​​the material receiving radiation and the thermal conductivity of the material. However, calcined dolomite and ferrosilicon are poor thermal conductors. The pellet pile formed by them absorbs radiant heat from the outside and transfers heat slowly inside the pellet pile, causing the radiation and conduction of the pellets themselves and each other to be seriously affected, and the heat transfer efficiency is significantly reduced, which in turn restricts the heat transfer efficiency and reaction speed of the reduction reaction, ultimately resulting in low efficiency, long time, high energy consumption and large emissions. It can be seen that to achieve high efficiency, low energy consumption and low emissions in magnesium metallurgy, it is necessary to start from the inherent mechanism of heat transfer and reaction to find a way out.

[0009] Compared with the heat and mass transfer effects between solids and solids, the heat and mass transfer of liquid-solid reaction mode has higher advantages. This is because the traditional liquid-solid mixing generally adds solids into the liquid and stirs for a long time to achieve homogenization. At the liquefaction temperature of the reducing agent, the reduction reaction is violent, the magnesium vapor overflows in large amounts instantly, and the internal pressure of the tank increases instantly, resulting in reduced production safety. In addition, the mass ratio between the reducing agent and the oxidizing agent is small, and the components cannot be mixed. This is also the fundamental reason why the traditional Pijiang method always maintains solid-solid interface heat and mass transfer. Considering that the essence of the high-temperature metallurgical process is chemical reaction and material mixing and separation, from the perspective of thermochemical reaction rate, chemical reaction is not a limiting link in the high-temperature metallurgical process, and material mixing and phase separation rate are often the main factors determining the production efficiency of high-temperature metallurgy. Under normal conditions, when the density of the liquid and solid phases is similar, mixing is relatively easy, but stirring is required to achieve uniform mixing. When the density difference between the liquid and solid phases is large, separation becomes the main trend, and various mechanical stirring methods are difficult to achieve uniform mixing, especially for two-phase mixing with a small liquid-solid ratio. Therefore, how to reasonably introduce liquid-solid reaction into magnesium metallurgy still needs further research. Summary of the invention

[0010] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device and method, which reduces the energy consumption of magnesium metallurgy, improves the reaction efficiency, and achieves energy saving and emission reduction.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device, comprising a transmission assembly, a hopper and a vertically arranged furnace body, wherein a primary material gathering cone tube and a secondary material gathering cone tube are fixedly installed inside the furnace body, the primary material gathering cone tube is located directly above the secondary material gathering cone tube, and a discharge port is opened below the secondary material gathering cone tube;

[0013] A liquid-solid mixed reaction tank is arranged above the first-level aggregate cone tube, a solid raw material dividing plate is fixedly installed inside the liquid-solid mixed reaction tank, and a gap is left between the solid raw material dividing plate and the inner wall of the liquid-solid mixed reaction tank; a solid raw material feeding pipe is fixedly installed on one side of the liquid-solid mixed reaction tank, an inner tube powder feeding thread is provided in the solid raw material feeding pipe, one end of the solid raw material feeding pipe extends into the liquid-solid mixed reaction tank, the other end of the solid raw material feeding pipe extends out through a hole provided in the furnace body and is rotatably connected to the furnace body through a bearing, and the solid raw material feeding pipe is connected to a transmission component capable of driving the rotation thereof, the end of the solid raw material feeding pipe is rotatably connected to the neck of the hopper through a rotary joint, and the neck of the hopper is connected to a solid raw material feeding vacuum valve;

[0014] A liquid reducing agent sprayer is provided inside the liquid-solid mixed reaction tank, and the liquid reducing agent sprayer is fixedly connected to a liquid reducing agent feeding pipe, which extends out through holes provided in the liquid-solid mixed reaction tank and the furnace body in turn and is rotatably connected to the liquid-solid mixed reaction tank, and the liquid reducing agent feeding pipe is connected to a liquid reducing agent feeding vacuum valve;

[0015] The solid raw material feed pipe and the liquid reducing agent feed pipe are both provided with heating rings; the furnace body is connected to a magnesium vapor collection system through a pipeline, the magnesium vapor collection system is connected to a vacuum system, a continuous slag outlet is opened at the bottom of the furnace body, and the slag outlet is connected to a seal.

[0016] Furthermore, the transmission assembly includes an adjustable speed motor and a driven pulley fixedly connected to the solid raw material feed pipe, the output shaft of the adjustable speed motor is fixedly connected to the driving pulley, and the driving pulley and the driven pulley are connected by a belt.

[0017] Furthermore, the rotary joint is a hydraulic rotary joint.

[0018] Furthermore, the solid raw material feed vacuum valve includes a primary solid raw material feed vacuum valve and a secondary solid raw material feed vacuum valve respectively connected to the neck of the hopper, and the neck of the hopper located between the primary solid raw material feed vacuum valve and the secondary solid raw material feed vacuum valve forms a vacuum bin for storing solid raw materials and is connected to a vacuum pumping system.

[0019] Furthermore, the liquid reductant feed vacuum valve includes a primary liquid reductant feed vacuum valve and a secondary liquid reductant feed vacuum valve, and the portion of the liquid reductant feed pipe located between the primary liquid reductant feed vacuum valve and the secondary liquid reductant feed vacuum valve forms a vacuum bin for storing liquid reductant and is connected to a vacuum pumping system.

[0020] Furthermore, the magnesium vapor collection system includes three magnesium vapor collectors respectively connected to the furnace body through pipelines, and the three magnesium vapor collectors are respectively connected to the vacuum system.

[0021] Furthermore, a fence is fixedly installed inside the furnace body, and the fence covers the periphery of the liquid-solid mixed reaction tank (15).

[0022] Furthermore, the sealing member is a cover plate connected to the slag outlet via a hinge, and a rubber ring for sealing the slag outlet is fixedly installed around the cover plate.

[0023] A negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy method comprises the following steps:

[0024] Step 1, close the primary solid raw material feeding vacuum valve and the primary liquid reducing agent feeding vacuum valve, open the secondary solid raw material feeding vacuum valve and the secondary liquid reducing agent feeding vacuum valve, use the vacuum pumping system to evacuate the inside of the furnace body, when the vacuum degree in the furnace body reaches the preset standard, close the secondary solid raw material feeding vacuum valve and the secondary liquid reducing agent feeding vacuum valve, load magnesium oxide powder into the hopper, and inject liquid reducing agent into the liquid reducing agent feeding pipe, open the primary solid raw material feeding vacuum valve and the primary liquid reducing agent feeding vacuum valve, wait for magnesium oxide powder and liquid reducing agent to enter the vacuum bin, close the primary solid raw material feeding vacuum valve and the primary liquid reducing agent feeding vacuum valve, then continue to evacuate until the vacuum degree in the furnace body reaches the preset standard, open the secondary solid raw material feeding vacuum valve and the secondary liquid reducing agent feeding vacuum valve, magnesium oxide powder and liquid reducing agent flow into the solid raw material feeding pipe and the liquid reducing agent feeding pipe respectively and are heated by the heating ring;

[0025] Step 2, the adjustable speed motor drives the driving pulley, and the driving pulley drives the driven pulley to rotate through the belt, so that the solid raw material feeding pipe rotates and drives the liquid-solid mixed reaction tank and the solid raw material dividing plate to rotate, and the magnesium oxide powder is transported to the inside of the liquid-solid mixed reaction tank by the powder feeding thread in the tube and thrown out from the gap between the solid raw material dividing plate and the liquid-solid mixed reaction tank under the action of centrifugal force; at the same time, the liquid reducing agent flows from the liquid reducing agent feeding pipe into the liquid reducing agent sprayer and is broken into tiny droplets, and the droplets quickly collide and mix with the magnesium oxide powder layer, and move downward under the action of centrifugal force and gravity, while further mixing and reacting to generate magnesium vapor;

[0026] Step 3, the magnesium oxide powder, liquid reducing agent and by-products that have not yet reacted are mixed and reacted in the process of settling to the first-stage aggregate cone tube and the second-stage aggregate cone tube in sequence, and the generated solid product is discharged from the discharge port at the bottom of the second-stage aggregate cone tube and falls into the bottom of the furnace body, and then concentrated and continuously discharged from the slag discharge port;

[0027] Step 4: Under the suction action of the vacuum system, gaseous magnesium flows out from the gap between the liquid-solid mixed reaction tank and the first-stage aggregate cone tube and the gap between the first-stage aggregate cone tube and the second-stage aggregate cone tube and is collected in a magnesium vapor collector. After condensation and crystallization, raw magnesium is obtained.

[0028] Furthermore, in step 4, three magnesium vapor collectors are operated alternately in a cycle to achieve continuous condensation and discharge.

[0029] Compared with the prior art, the present invention has the following technical effects:

[0030] The present invention aims to solve the problem of low solid-solid heat and mass transfer efficiency in the traditional Pidgeon method. The magnesium oxide powder and the liquid reducing agent are first heated by a heating ring, and then the centrifugal force generated by the rotation of the liquid-solid mixed reaction tank is used to sprinkle the high-temperature magnesium oxide powder from the gap between the solid raw material dividing plate and the inner wall of the liquid-solid mixed reaction tank, forming a magnesium oxide layer of a certain thickness in a supergravity environment, and increasing the exchange interface between the magnesium oxide layer and the tiny droplets sprayed by the high-temperature liquid reducing agent sprayer, thereby forming impact, contact and coating of each particle from the surface of the material layer to the deep layer, forming a liquid@solid structure, and realizing rapid and uniform mixing and reaction. Compared with traditional solid-solid interface mixing, solid-liquid interface mixing is more efficient; moreover, during the downward sedimentation process, the unfinished materials are re-mixed and aggregated through the first-stage aggregation cone tube and the second-stage aggregation cone tube, which increases the reaction opportunities, improves the reduction rate, and reduces resource consumption; therefore, the present invention has higher heat transfer, mass transfer and energy transfer effects, significantly promotes the reduction reaction efficiency, shortens the reaction time, reduces energy consumption and carbon emissions, and improves the magnesium metallurgical efficiency and the reduction rate of magnesium in magnesium oxide powder. According to calculations, the reduction rate of magnesium can be increased by more than 1 to 3%, laying a foundation for efficient magnesium metallurgy.

[0031] The present invention realizes continuous crystallization by arranging three magnesium vapor collectors to form a standby-condensation-discharging cycle in sequence; at the same time, through one-time reaction control, the problem of excessive waste or recovery of reducing agent is avoided; more importantly, through the continuous output of slag, the recovery and utilization of slag heat is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : Schematic diagram of the three-dimensional structure of the negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device of the present invention;

[0033] Figure 2 : A schematic diagram of the front view of the negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device of the present invention;

[0034] Figure 3 : The present invention Figure 2 Schematic diagram of the cross-sectional structure at the middle BB;

[0035] Figure 4 : The present invention Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle.

[0036] In the figure: 1. furnace body; 2. primary solid raw material feeding vacuum valve; 3. solid raw material feeding pipe; 4. heating ring; 5. bearing; 6. belt; 7. adjustable speed motor; 8. magnesium vapor collecting system; 9. vacuum system; 10. liquid reducing agent feeding pipe; 11. primary liquid reducing agent feeding vacuum valve; 12. secondary liquid reducing agent feeding vacuum valve; 13. secondary solid raw material feeding vacuum valve; 14. solid raw material dividing plate; 15. liquid-solid mixed reaction tank; 16. liquid reducing agent sprayer; 17. primary aggregate cone pipe; 18. secondary aggregate cone pipe; 19. slag outlet; 20. powder feeding thread in the pipe; 21. enclosure; 22. hopper; 23. rotary joint; 24. driving pulley; 25. driven pulley. DETAILED DESCRIPTION

[0037] The specific contents of the present invention are further explained in detail below in conjunction with embodiments.

[0038] like Figure 1 to Figure 4 As shown, a negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device comprises an adjustable speed motor 7, a hopper 22 and a vertically arranged furnace body 1, wherein a primary material gathering cone tube 17 and a secondary material gathering cone tube 18 are fixedly installed inside the furnace body 1, the primary material gathering cone tube 17 is located directly above the secondary material gathering cone tube 18, and a discharge port is opened below the secondary material gathering cone tube 18;

[0039] A liquid-solid mixed reaction tank 15 is provided above the first-level aggregate cone 17, and a solid raw material dividing plate 14 is fixedly installed inside the liquid-solid mixed reaction tank 15. A gap is left around the solid raw material dividing plate 14 and the inner wall of the liquid-solid mixed reaction tank 15. A temporary chamber for accommodating magnesium oxide powder discharged from the solid raw material feeding pipe 3 is formed between the solid raw material dividing plate 14 and the liquid-solid mixed reaction tank 15, so as to prevent a large amount of magnesium oxide powder from pouring into the reaction chamber on the other side of the solid raw material dividing plate 14, thereby causing an insufficient reaction;

[0040] A horizontally arranged solid raw material feeding pipe 3 is fixedly installed on one side of the liquid-solid mixed reaction tank 15, and an inner tube powder feeding thread 20 is provided in the solid raw material feeding pipe 3 to facilitate the forward conveying of magnesium oxide powder. One end of the solid raw material feeding pipe 3 extends into the liquid-solid mixed reaction tank 15, and the other end of the solid raw material feeding pipe 3 extends out through a hole provided in the furnace body 1. The middle part of the solid raw material feeding pipe 3 is rotatably connected to the furnace body 1 through a bearing 5, and a driven pulley 25 is fixedly installed on the solid raw material feeding pipe 3; the output shaft of the adjustable speed motor 7 is fixedly connected to a driving pulley 24, and the driving pulley 24 is connected to the driven pulley 25 through a belt 6. When the adjustable speed motor 7 is working, it drives the driving pulley 24 to rotate, thereby driving the driven pulley 25 to rotate through the belt 6, and the driven pulley 25 drives the solid raw material feeding pipe 3 to rotate, and the magnesium oxide powder in the solid raw material feeding pipe 3 is conveyed to the liquid-solid mixed reaction tank 15 by the inner tube powder feeding thread 20;

[0041] The end of the solid raw material feed pipe 3 is rotatably connected to the neck of the hopper 22 via a rotary joint 23. The rotary joint 23 is a hydraulic rotary joint, which can ensure the airtight cooperation between the static hopper 22 and the solid raw material feed pipe 3 in the rotating state. The hopper 22 is fixed inside the factory building by a hoisting device and always remains in a static state.

[0042] The neck of the hopper 22 is connected from top to bottom with a primary solid raw material feeding vacuum valve 2 and a secondary solid raw material feeding vacuum valve 13. The neck of the hopper 22 located between the primary solid raw material feeding vacuum valve 2 and the secondary solid raw material feeding vacuum valve 13 forms a vacuum bin for temporarily storing solid raw materials and is connected to a vacuum pumping system 9. The amount of magnesium oxide powder entering the solid raw material feeding pipe 3 can be controlled by the primary solid raw material feeding vacuum valve 2 and the secondary solid raw material feeding vacuum valve 13. The vacuum bin is evacuated by the vacuum pumping system 9 to prevent the magnesium oxide powder from bringing air into the furnace body 1.

[0043] A liquid reducing agent sprayer 16 is provided inside the liquid-solid mixed reaction tank 15, and the liquid reducing agent sprayer 16 is fixedly connected to two horizontally arranged liquid reducing agent feeding pipes 10, and the liquid reducing agent feeding pipes 10 extend out through holes provided in the liquid-solid mixed reaction tank 15 and the furnace body 1 in sequence, and are rotatably connected to the liquid-solid mixed reaction tank 15, and the liquid reducing agent sprayer 16 is stationary relative to the liquid-solid mixed reaction tank 15;

[0044] The liquid reducing agent sprayer 16 adopts centrifugal atomization under vacuum; it can also adopt inert and reducing gases such as argon and helium for atomization under negative pressure or normal pressure;

[0045] The liquid reducing agent feeding vacuum valve comprises a primary liquid reducing agent feeding vacuum valve 11 and a secondary liquid reducing agent feeding vacuum valve 12. The portion of the liquid reducing agent feeding pipe 10 located between the primary liquid reducing agent feeding vacuum valve 11 and the secondary liquid reducing agent feeding vacuum valve 12 forms a vacuum chamber for storing the liquid reducing agent and is connected to the vacuum pumping system 9. The primary liquid reducing agent feeding vacuum valve 11 and the secondary liquid reducing agent feeding vacuum valve 12 can control the amount of the liquid reducing agent entering the liquid reducing agent sprayer 16, thereby preventing the waste of the liquid reducing agent. The vacuum chamber is evacuated by the vacuum pumping system 9 to prevent the liquid reducing agent from bringing air into the furnace body 1.

[0046] The solid raw material feed pipe 3 and the liquid reducing agent feed pipe 10 are both provided with a heating ring 4 for heating the magnesium oxide powder and the liquid reducing agent to keep the magnesium oxide powder and the liquid reducing agent at high temperature, so as to react quickly and generate gaseous magnesium element;

[0047] The furnace body 1 is connected to a magnesium vapor collecting system 8 through a pipeline. The magnesium vapor collecting system 8 includes three magnesium vapor collectors respectively connected to the furnace body 1 through pipelines. The three magnesium vapor collectors are respectively connected to a vacuum system 9. With the help of the suction effect of the vacuum system 9, gaseous magnesium is fully discharged from the gap between the liquid-solid mixed reaction tank 15 and the first-level aggregation cone tube 17 and the gap between the first-level aggregation cone tube 17 and the second-level aggregation cone tube 18 and collected in the magnesium vapor collector. After condensation and crystallization, raw magnesium is obtained. The three magnesium vapor collectors are cyclically alternately condensed, discharged and used for standby, thereby realizing continuous crystallization of raw magnesium.

[0048] A slag outlet 19 is provided at the bottom of the furnace body 1, and the slag outlet 19 is connected to a cover plate by a hinge. A rubber ring for sealing the slag outlet 19 is fixedly installed around the cover plate. In the slag discharge state, the cover plate is opened to facilitate the centralized collection of slag. Otherwise, the slag outlet 19 is sealed by the cover plate and the rubber ring, so that the furnace body 1 is in a closed state.

[0049] By collecting slag in a centralized manner, not only can continuous production of magnesium reduction be achieved, but the heat carried by the slag can also be recovered through heat exchange, which can be used for heat preservation of materials in front of the furnace and heating of production water, thus realizing the recovery and utilization of waste heat.

[0050] Preferably, a baffle 21 is fixedly installed inside the furnace body 1, and the baffle 21 covers the periphery of the liquid-solid mixed reaction tank 15, which can prevent the magnesium oxide powder from being thrown to a far range by centrifugal force and thus unable to fully participate in the reaction.

[0051] Preferably, the first-stage conical tube 17 is funnel-shaped, and the diameter of the upper part is larger than the diameter of the lower part, so that the magnesium oxide powder and the liquid reducing agent can be gathered, mixed and reacted again through the first-stage conical tube 17 during the downward sedimentation process.

[0052] The secondary aggregation cone 18 is a cone-shaped tube that is larger at the top and smaller at the bottom. During the sedimentation process, it further promotes the re-aggregation and mixing of the magnesium oxide powder and the liquid reducing agent, and reduces the resonance caused by the liquid-solid mixing reaction tank that leads to insufficient mixing of the magnesium oxide powder and the liquid reducing agent.

[0053] A negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy method comprises the following steps:

[0054] Step 1: close the primary solid raw material feeding vacuum valve and the primary liquid reducing agent feeding vacuum valve 11, open the secondary solid raw material feeding vacuum valve 13 and the secondary liquid reducing agent feeding vacuum valve 12, use the vacuum pumping system 9 to evacuate the inside of the furnace body 1, wait until the vacuum degree in the furnace body 1 reaches the preset standard, close the secondary solid raw material feeding vacuum valve 13 and the secondary liquid reducing agent feeding vacuum valve 12, load the magnesium oxide powder into the hopper 22, and inject the liquid reducing agent into the liquid reducing agent feeding pipe 10, open the primary solid raw material feeding vacuum valve 13 and the secondary liquid reducing agent feeding vacuum valve 12, and then turn on the primary solid raw material feeding vacuum valve 13. The raw material feeding vacuum valve 2 and the first-level liquid reducing agent feeding vacuum valve 11 are closed until the magnesium oxide powder and the liquid reducing agent enter the vacuum chamber, and then the first-level solid raw material feeding vacuum valve 2 and the first-level liquid reducing agent feeding vacuum valve 11 are closed, and then the vacuum is continuously evacuated until the vacuum degree in the furnace body 1 reaches the preset standard, and the second-level solid raw material feeding vacuum valve 13 and the second-level liquid reducing agent feeding vacuum valve 12 are opened, and the magnesium oxide powder and the liquid reducing agent flow into the solid raw material feeding pipe 3 and the liquid reducing agent feeding pipe 10 respectively and are heated by the heating ring 4;

[0055] Step 2, the adjustable speed motor 7 drives the active pulley 24, and the active pulley 24 drives the driven pulley 25 to rotate through the belt 6, so that the solid raw material feeding pipe 3 rotates and drives the liquid-solid mixed reaction tank 15 and the solid raw material dividing plate 14 to rotate, and the magnesium oxide powder is transported to the inside of the liquid-solid mixed reaction tank 15 by the powder feeding thread 20 in the tube and thrown out from the gap between the solid raw material dividing plate 14 and the liquid-solid mixed reaction tank 15 under the action of centrifugal force; at the same time, the liquid reducing agent flows from the liquid reducing agent feeding pipe 10 into the liquid reducing agent sprayer 16 and is broken into tiny droplets, and the droplets collide and mix with the magnesium oxide powder rapidly to form a liquid-solid coating structure, which settles downward and reacts to generate gaseous magnesium element. The reaction formula is as follows:

[0056] Si / Al(l)+MgO(s)=Mg(g)↑+SiO2 / Al2O3(s)

[0057] Step 3, during the downward movement of the mixture of the liquid reducing agent and the magnesium oxide powder, due to the better fluidity of the liquid state, the mixture moves from the surface where the liquid and solid begin to mix to the deep part under the action of centrifugal force, and mixes and reacts with more magnesium oxide powder. During the downward sedimentation, the magnesium oxide powder and the liquid reducing agent and the by-products that have not reacted are successively deposited into the primary aggregate cone tube 17 and the secondary aggregate cone tube 18, and are remixed and reacted in the process of successively settling into the primary aggregate cone tube 17 and the secondary aggregate cone tube 18. The solid products produced by the reaction are discharged from the discharge port at the bottom of the secondary aggregate cone tube 18 and fall into the bottom of the furnace body 1, and then discharged from the slag discharge port 19 in a concentrated manner;

[0058] Step 4: Under the suction action of the vacuum system 9, the gaseous magnesium element flows out from the gap between the liquid-solid mixed reaction tank 15 and the first-level gathering cone tube 17 and the gap between the first-level gathering cone tube 17 and the second-level gathering cone tube 18 and is collected in one of the magnesium vapor collectors for condensation and crystallization to obtain raw magnesium. Then another magnesium vapor collector is put into use to start collecting gaseous magnesium, and the remaining one is reserved; and so on, the three magnesium vapor collectors are cyclically condensed, discharged and reserved alternately to achieve continuous crystallization.

[0059] The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy device and method of this embodiment are suitable for the reduction of magnesium in calcined dolomite, light-burned or heavy-burned magnesia and their mixtures, and the reducing agent used can be silicon-based and aluminum-based alloys such as ferrosilicon, silicon-calcium, metallic aluminum and aluminum-iron, and has a relatively wide range of applications.

[0060] The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy device and method of the present embodiment can control the flow rate of solid and liquid through the solid raw material feeding vacuum valve and the liquid reducing agent feeding vacuum valve, and control the vacuum degree inside the furnace body through the vacuum pumping system. The magnesium oxide powder and the reducing agent are heated by the heating ring to control the temperature inside the furnace body, so that the discharge and crystallization speeds are controllable, and automated production can be achieved by adding temperature sensors, etc.

[0061] Although the negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device of this embodiment is similar to a vertical furnace, it does not have the relatively static reduction of the pellet pile of the traditional vertical furnace. Instead, the raw materials of ferrosilicon, metallic aluminum, silicon calcium, aluminum iron and other reducing agents and calcined dolomite, magnesia and other oxidants used in the traditional Pidgeon process are melted and heated separately to achieve liquid-solid reaction. Therefore, the volume expansion caused by the subsequent cooling and phase change of the product significantly reduces the stress on the furnace tube, greatly improving the stress environment and conditions of the furnace tube.

[0062] The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device and method of this embodiment can make use of the high energy of the upstream high-temperature reducing agent and the mixed reaction of the heated oxidant; it can also be designed through the magnesium metallurgical industrial park, the waste heat of the upstream magnesium oxide mineral roasting processing above 1000°C and the waste heat of the smelting of reducing agents such as ferrosilicon, metallic aluminum, silicon calcium, and aluminum iron to achieve magnesium metallurgical liquid-solid reduction above 1000°C, and then the subsequent waste heat of raw magnesium refining is utilized. Through energy combination, the energy consumption, carbon emissions and efficiency of the whole process are optimized, thereby building a low-energy magnesium industrial park and creating a world-class magnesium metallurgical industrial line.

[0063] The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy device and method of this embodiment transforms the solid-solid heat transfer and value transfer of the traditional Pijiang method for magnesium smelting into a liquid-solid heat transfer mechanism, significantly improving the heat transfer and mass transfer efficiency, thereby improving the reaction efficiency, and realizing rapid mixing and subsequent convergence and dispersion flow through the collision, contact and coating between the droplets of molten atomization and the powder curtain formed by powder dispersion and sedimentation, thereby forming multiple mixing, realizing efficient and rapid mixing and reaction of liquid and solid, and fundamentally getting rid of the problems of insufficient mixing and low reduction efficiency of the relatively static point-line contact reduction of the traditional Pijiang method; in addition, considering the viscosity of the liquid phase itself Due to the influence of the degree and the bonding force between the other solid phases, mixing under a single gravity requires sufficient time, while supergravity is directional and the intensity is adjustable, which can achieve effective control of the degree and time of mixing of the liquid-solid two-phases. In addition, under the action of the supergravity field, there are many interaction interfaces between the powder and the droplets, the interaction time is short, and the mixing uniformity is good. Therefore, this embodiment adopts a mixing technology that combines centrifugal liquid atomization with centrifugal powder dispersion, which not only achieves high efficiency and uniformity of mixing, but also effectively controls the reaction rate between the liquid-phase reductant and the solid-phase oxidant by controlling the mixing speed, thereby improving the reaction efficiency and reduction efficiency.

[0064] In summary, the negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device and method of this embodiment achieve effective energy saving through the following three ways: first, micro energy saving, converting solid-solid reaction into liquid-solid reaction, reducing reaction energy consumption; second, monomer energy saving, centralized collection of slag, setting heat recovery pipeline at the bottom of the furnace shell, etc., using heat exchange system, to achieve waste heat recovery and utilization, so as to reduce the energy consumption of metallurgical process, and at the same time, complete the continuous slag discharge; third, system comprehensive energy saving, can utilize the energy flow and logistics coordination between upstream and downstream, and utilize the upstream reducing agent smelting waste heat and magnesium oxide mineral roasting waste heat as the main energy source of magnesium metallurgy, to achieve system comprehensive energy saving, achieve energy saving of more than 40%, and reduce carbon emissions by more than 30% by improving efficiency and reducing energy consumption.

Claims

1. A negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device, characterized in that: The furnace body (1) comprises a transmission assembly, a hopper (22) and a furnace body (1), wherein a primary material gathering cone tube (17) and a secondary material gathering cone tube (18) are fixedly installed inside the furnace body (1), the primary material gathering cone tube (17) is located directly above the secondary material gathering cone tube (18), and a discharge port is provided below the secondary material gathering cone tube (18); A liquid-solid mixed reaction tank (15) is arranged above the first-stage aggregate cone tube (17), a solid raw material dividing plate (14) is fixedly installed inside the liquid-solid mixed reaction tank (15), and gaps are left around the solid raw material dividing plate (14) and the inner wall of the liquid-solid mixed reaction tank (15); a horizontally arranged solid raw material feeding pipe (3) is fixedly installed on one side of the liquid-solid mixed reaction tank (15), and a tube powder feeding thread (20) is provided inside the solid raw material feeding pipe (3). One end of the raw material feed pipe (3) extends into the interior of the liquid-solid mixed reaction tank (15), and the other end of the solid raw material feed pipe (3) extends out through a hole provided in the furnace body (1) and is rotatably connected to the furnace body (1) via a bearing (5), and the solid raw material feed pipe (3) is connected to a transmission component capable of driving the solid raw material feed pipe to rotate, and the end of the solid raw material feed pipe (3) is rotatably connected to the neck of the hopper (22) via a rotary joint (23), and the neck of the hopper (22) is connected to a solid raw material feed vacuum valve; A liquid reducing agent sprayer (16) is provided inside the liquid-solid mixed reaction tank (15), and the liquid reducing agent sprayer (16) is fixedly connected to a horizontally arranged liquid reducing agent feeding pipe (10), and the liquid reducing agent feeding pipe (10) sequentially extends through holes provided in the liquid-solid mixed reaction tank (15) and the furnace body (1) and is rotatably connected to the liquid-solid mixed reaction tank (15), and the liquid reducing agent feeding pipe (10) is connected to a liquid reducing agent feeding vacuum valve; The solid raw material feed pipe (3) and the liquid reducing agent feed pipe (10) are both provided with a heating ring (4); the furnace body (1) is connected to a magnesium vapor collection system (8) through a pipeline, the magnesium vapor collection system (8) is connected to a vacuum pumping system (9), and a slag outlet (19) is provided at the bottom of the furnace body (1), and the slag outlet (19) is connected to a sealing member.

2. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device according to claim 1 is characterized in that: The transmission assembly comprises an adjustable speed motor (7) and a driven pulley (25) fixedly connected to a solid raw material feed pipe (3); an output shaft of the adjustable speed motor (7) is fixedly connected to a driving pulley (24); and the driving pulley (24) and the driven pulley (25) are connected via a belt (6).

3. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device according to claim 1 or 2, characterized in that: The rotary joint (23) is a hydraulic rotary joint.

4. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device according to claim 2 is characterized in that: The solid raw material feeding vacuum valve comprises a primary solid raw material feeding vacuum valve (2) and a secondary solid raw material feeding vacuum valve (13) respectively connected to the neck of the hopper (22); the neck of the hopper (22) located between the primary solid raw material feeding vacuum valve (2) and the secondary solid raw material feeding vacuum valve (13) forms a vacuum bin for storing solid raw materials and is connected to a vacuum pumping system (9).

5. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device according to claim 4 is characterized in that: The liquid reducing agent feeding vacuum valve comprises a primary liquid reducing agent feeding vacuum valve (11) and a secondary liquid reducing agent feeding vacuum valve (12); the portion of the liquid reducing agent feeding pipe (10) located between the primary liquid reducing agent feeding vacuum valve (11) and the secondary liquid reducing agent feeding vacuum valve (12) forms a vacuum chamber for storing the liquid reducing agent and is connected to a vacuum pumping system (9).

6. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy device according to claim 5, characterized in that: The magnesium vapor collection system (8) comprises three magnesium vapor collectors respectively connected to the furnace body (1) through pipelines, and the three magnesium vapor collectors are respectively connected to the vacuum pumping system (9).

7. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgical device according to claim 1 or 2, characterized in that: A baffle (21) is fixedly installed inside the furnace body (1), and the baffle (21) covers the periphery of the liquid-solid mixed reaction tank (15).

8. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy device according to claim 1 or 2, characterized in that: The sealing member is a cover plate connected to the slag outlet (19) via a hinge, and a rubber ring for sealing the slag outlet (19) is fixedly installed around the circumference of the cover plate.

9. A negative pressure atomization and high gravity enhanced liquid-solid reaction magnesium metallurgy method based on the negative pressure atomization and high gravity enhanced liquid-solid reaction magnesium metallurgy device according to claim 6, characterized in that: The steps include: Step 1: close the primary solid raw material feeding vacuum valve (2) and the primary liquid reducing agent feeding vacuum valve (11), open the secondary solid raw material feeding vacuum valve (13) and the secondary liquid reducing agent feeding vacuum valve (12), use the vacuum pumping system (9) to evacuate the inside of the furnace body (1), wait until the vacuum degree in the furnace body (1) reaches a preset standard, close the secondary solid raw material feeding vacuum valve (13) and the secondary liquid reducing agent feeding vacuum valve (12), load magnesium oxide powder into the hopper (22), and inject liquid reducing agent into the liquid reducing agent feeding pipe (10), open the primary solid raw material feeding vacuum valve (13), and evacuate the inside of the furnace body (1). The first solid raw material feeding vacuum valve (2) and the first liquid reducing agent feeding vacuum valve (11) are opened, and when the magnesium oxide powder and the liquid reducing agent enter the vacuum chamber, the first solid raw material feeding vacuum valve (2) and the first liquid reducing agent feeding vacuum valve (11) are closed, and then vacuuming is continued until the vacuum degree in the furnace body (1) and the vacuum chamber reaches a preset standard, and the second solid raw material feeding vacuum valve (13) and the second liquid reducing agent feeding vacuum valve (12) are opened, and the magnesium oxide powder and the liquid reducing agent flow into the solid raw material feeding pipe (3) and the liquid reducing agent feeding pipe (10) respectively and are heated by the heating ring (4); Step 2, the adjustable speed motor (7) drives the driving pulley (24), and the driving pulley (24) drives the driven pulley (25) to rotate through the belt (6), so that the solid raw material feeding pipe (3) rotates and drives the liquid-solid mixed reaction tank (15) and the solid raw material dividing plate (14) to rotate, and the magnesium oxide powder is transported to the inside of the liquid-solid mixed reaction tank (15) by the powder feeding thread (20) in the pipe and thrown out from the gap between the solid raw material dividing plate (14) and the liquid-solid mixed reaction tank (15) under the action of centrifugal force; at the same time, the liquid reducing agent flows from the liquid reducing agent feeding pipe (10) into the liquid reducing agent sprayer (16) and is broken into tiny droplets, and the droplets collide and mix with the magnesium oxide powder rapidly, and move downward under the combined action of gravity and centrifugal force, while undergoing a reduction reaction to generate magnesium vapor; Step 3, the magnesium oxide powder, liquid reducing agent and by-products that have not yet reacted are remixed and reacted in the process of settling to the primary aggregate cone tube (17) and the secondary aggregate cone tube (18) in sequence, and the solid products produced by the reaction are discharged from the discharge port at the bottom of the secondary aggregate cone tube (18) and fall into the bottom of the furnace body (1), and then discharged from the slag discharge port (19); Step 4: Under the suction action of the vacuum system (9), gaseous magnesium flows out from the gap between the liquid-solid mixed reaction tank (15) and the first-stage aggregate cone tube (17) and the gap between the first-stage aggregate cone tube (17) and the second-stage aggregate cone tube (18) and is collected in a magnesium vapor collector. After condensation and crystallization, raw magnesium is obtained.

10. The negative pressure atomization and ultra-gravity enhanced liquid-solid reaction magnesium metallurgy method according to claim 9, characterized in that: In step 4, three magnesium vapor collectors work alternately in a cycle to continuously achieve condensation and discharge.

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