High-efficiency low-carbon vertical tank supergravity mixed magnesium smelting device and method

Abstract

The invention discloses an efficient low-carbon vertical tank supergravity mixed magnesium smelting device and method.The device comprises a furnace body and a supergravity solid-liquid mixing system, and the supergravity solid-liquid mixing system comprises a first-stage material gathering taper pipe fixedly arranged in the furnace body and a second-stage material gathering taper pipe provided with a discharging port; a liquid-solid mixing reaction material tank internally and fixedly connected with a solid raw material distributing plate is arranged above the first-stage material gathering taper pipe, the liquid-solid mixing reaction material tank is fixedly connected with a solid raw material feeding pipe provided with a solid raw material feeding vacuum valve, and the solid raw material feeding pipe is rotationally connected with the furnace body and connected with a transmission assembly. A liquid-state reducing agent atomizing disc is fixedly arranged in the liquid-solid mixing reaction material tank and is rotationally connected with a liquid-state reducing agent feeding pipe provided with a liquid-state reducing agent feeding vacuum valve; the furnace body is connected with the magnesium steam collecting system, the magnesium steam collecting system is connected with the vacuumizing system, and a slag outlet is formed in the bottom of the furnace body and connected with a sealing piece. According to the invention, the reaction efficiency is improved, the energy consumption is reduced, and energy conservation and emission reduction are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of magnesium metallurgy, and in particular relates to a high-efficiency low-carbon vertical tank ultra-gravity mixed magnesium smelting 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, the Pidgeon process has the advantages of small investment, simple process and easy operation.

[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] In the existing Pijiang process magnesium smelting technology, whether it is horizontal tank reduction or vertical tank reduction, there are the following major problems: First, high energy consumption and large carbon emissions. The heat source for external heating in the 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, which has high energy consumption and large CO2 emissions. Second, it takes a long time and has low efficiency. The horizontal tube reduction time is as high as about 8 to 12 hours. Even if internal and external heating is used, it still takes more than 5 hours, which is inefficient. Third, the intermittent production method cannot be realized due to the limited tank volume. Although some vertical tube types have achieved continuity, the stability is poor and has not yet become the mainstream of industrial applications. Fourth, the reduction rate is low. Since the solid-solid reaction in magnesium metallurgy is affected by mass transfer and heat transfer, it is difficult to achieve continuous production. Due to the restriction of efficiency, the reduction rate of MgO is only about 80%, and it is very difficult to increase it further, thus causing greater waste of resources and energy; Fifth, the heat transfer mode is single and the heat transfer efficiency is low. First, since the 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; Second, 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 limited 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; Third, 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] In general, compared with horizontal reduction, the vertical tube reduction developed in recent years has more advantages and has become the mainstream direction of technological development in the magnesium metallurgical industry. It is also the goal of continuous upgrading and development by industry insiders. For example, Professor Wang Xiaogang's team from Xi'an University of Science and Technology proposed the idea of ​​internal and external heating; Professor Zhang Ting'an's team from the Metallurgical Department of Northeastern University proposed a method for 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 radiant heat absorbed from the outside of the pellet pile formed by them is slowly transferred inside the pellet pile, causing the radiation and conduction of the pellets themselves and between 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 effect between solid and solid, the heat and mass transfer of liquid-solid reaction has higher advantages. However, the traditional liquid-solid mixing generally adds solid to liquid and stirs for a long time to achieve homogenization. At the liquefaction temperature of the reducing agent, the reduction reaction is violent, the amount of magnesium vapor overflows 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 the 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 it requires the help of stirring to achieve uniform mixing. When the density difference between the liquid and solid phases is large, separation becomes the main trend, and various stirring methods are difficult to achieve uniform mixing, especially for the mixing of two phases with a small liquid-solid ratio. Therefore, how to effectively apply liquid-solid mixing to magnesium smelting 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 high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device and method, which reduces the energy consumption of magnesium metallurgy, improves 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] An efficient and low-carbon vertical tank ultra-gravity mixed magnesium smelting device, comprising a furnace body, an ultra-gravity solid-liquid mixing system, a magnesium vapor collection system and a vacuum pumping system;

[0013] The supergravity solid-liquid mixing system comprises a transmission assembly and a primary material gathering cone tube and a secondary material gathering cone tube fixedly installed inside the furnace body, wherein 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;

[0014] A liquid-solid mixed reaction tank is provided above the first-level aggregate cone tube, a horizontal solid raw material dividing plate is installed inside the liquid-solid mixed reaction tank, and a gap is provided between the circumference of the solid raw material dividing plate and the inner wall of the liquid-solid mixed reaction tank; a vertical solid raw material feeding pipe is fixedly installed on the liquid-solid mixed reaction tank, the solid raw material feeding pipe is connected to a solid raw material feeding vacuum valve, 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 thereto, and the solid raw material feeding pipe is connected to a transmission component capable of driving it to rotate, and a hopper is fixedly installed on the top of the solid raw material feeding pipe;

[0015] A liquid reducing agent atomizing disk is fixedly installed inside the liquid-solid mixed reaction tank, and the liquid reducing agent atomizing disk is rotatably connected to a vertical liquid reducing agent feeding pipe, and the liquid reducing agent feeding pipe extends out through holes provided in the liquid-solid mixed reaction tank, the first-level aggregate cone tube, the second-level aggregate cone tube, and the furnace body in sequence and is connected to a liquid reducing agent feeding vacuum valve, and the diameter of the hole provided in the liquid-solid mixed reaction tank is larger than the diameter of the liquid reducing agent feeding pipe so that the liquid-solid mixed reaction tank can rotate relative to the liquid reducing agent feeding pipe, and the liquid reducing agent feeding pipe is fixedly connected to the first-level aggregate cone tube, the second-level aggregate cone tube, and the furnace body;

[0016] 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 the magnesium vapor collection system through a pipeline, the magnesium vapor collection system is connected to the vacuum system, a slag outlet is opened at the bottom of the furnace body, and the slag outlet is connected to a sealing member.

[0017] Furthermore, the transmission assembly includes an adjustable differential motor and a driven pulley fixedly connected to the solid raw material feed pipe, the output shaft of the adjustable differential motor is fixedly connected to the driving pulley, and the driving pulley and the driven pulley are connected by a belt.

[0018] Furthermore, the relative positions of the inner wall of the liquid-solid mixed reaction tank and the outer wall of the solid raw material feed pipe are provided with crushing nails staggered in the horizontal direction, the length of the crushing nails gradually increases from top to bottom, and the vertical distance between two adjacent crushing nails above and below gradually decreases.

[0019] 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 solid raw material feed pipe, and the portion of the solid raw material feed pipe 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.

[0020] 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.

[0021] Furthermore, the magnesium vapor collection system includes three magnesium vapor collectors respectively connected to the furnace body through pipelines, the three magnesium vapor collectors are respectively connected to the vacuum system, and the pipelines are connected to vacuum valves.

[0022] Furthermore, a circle of saw teeth is provided on the upper surface of the liquid reducing agent atomization disk along its circumference.

[0023] 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.

[0024] A high-efficiency and low-carbon vertical tank ultra-gravity mixed magnesium smelting method comprises the following steps:

[0025] Step 1, close the first-level solid raw material feeding vacuum valve and the first-level liquid reducing agent feeding vacuum valve, open the second-level solid raw material feeding vacuum valve and the second-level liquid reducing agent feeding vacuum valve, use the vacuum pumping system to evacuate the inside of the furnace body, wait until the vacuum degree in the furnace body reaches a preset standard, close the second-level solid raw material feeding vacuum valve and the second-level 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 through a peristaltic pump, open the first-level solid raw material feeding vacuum valve and the first-level liquid reducing agent feeding vacuum valve, wait for magnesium oxide powder and liquid reducing agent to enter the vacuum bin, close the first-level solid raw material feeding vacuum valve and the first-level liquid reducing agent feeding vacuum valve, then continue to evacuate until the vacuum degree in the furnace body and the vacuum bin reaches the preset standard, open the second-level solid raw material feeding vacuum valve and the second-level liquid reducing agent feeding vacuum valve, and the magnesium oxide powder and the 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;

[0026] Step 2, the adjustable differential motor drives the active pulley, and the active pulley drives the driven pulley to rotate through the belt, so that the solid raw material feed pipe rotates and drives the liquid-solid mixed reaction tank and the solid raw material dividing plate to rotate, and the magnesium oxide powder enters the liquid-solid mixed reaction tank under the action of gravity, and is divided 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 feed pipe into the liquid reducing agent atomization disk under the action of negative pressure and is thrown out under the action of centrifugal force to become tiny droplets, and the droplets quickly collide, mix and react with the surface of the magnesium oxide powder layer, and under the action of centrifugal force, the liquid reducing agent gradually flows from the surface of the magnesium oxide layer to the inside, and is divided, sheared and filmized during the flow process, so as to wrap the particles inside the material layer, form a liquid @ solid structure, and cause a reduction reaction;

[0027] Step 3, the unreacted magnesium oxide powder, liquid reducing agent and by-products are sequentially settled to the primary aggregate cone tube and the secondary aggregate cone tube, and are mixed and reacted again in the primary aggregate cone tube and the secondary aggregate cone tube. The solid product is discharged from the discharge port at the bottom of the secondary aggregate cone tube and falls into the bottom of the furnace body, and then discharged from the slag discharge port;

[0028] 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.

[0029] Furthermore, in step 4, three magnesium vapor collectors respectively used for standby, crystallization and discharging are operated alternately in a cycle to continuously realize condensation and discharging.

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] The present invention aims to solve the problem of low solid-solid heat transfer and mass transfer efficiency in the traditional Pidgeon method. The magnesium oxide powder is first heated and the liquid reducing agent is kept warm. Then, the centrifugal force generated by the rotation of the liquid-solid mixed reaction tank is used to divide the high-temperature magnesium oxide powder into a material layer of a certain thickness. The magnesium oxide material layer and the tiny droplets of the high-temperature liquid reducing agent atomized by centrifugal force under the action of supergravity are counteracted and contacted to form a liquid@solid structure, and a reaction occurs. Compared with traditional solid-solid interface mixing, solid-liquid interface mixing is more efficient, and the wettability and mass transfer effect of the solid are better. Moreover, under the action of supergravity, the dynamic factors (i.e., buoyancy factors) of the liquid and solid phases become larger, the relative sliding speed becomes larger, and the huge shear stress overcomes the surface tension, so that the liquid phase extends a huge interphase contact interface, the two-phase interaction time is more sufficient, and the mixing is more uniform, thereby strengthening the mass transfer process, significantly enhancing the heat and momentum transfer, strengthening the chemical reaction process, and increasing the linear velocity of the gas phase due to the increase in the liquid flooding limit, which is beneficial to the collection of magnesium vapor; in addition, since it does not involve the static reduction process of the pellet pile, the heat and mass transfer efficiency between the calcined dolomite powder and the liquid reducing agent is accelerated, thereby improving the reaction efficiency. It is estimated that the reduction rate can be increased by at least 1 to 3%. In short, the present invention introduces hypergravity field energy to assist solid-liquid mixing, thereby enhancing mass transfer and heat transfer, shortening reaction time, reducing energy consumption and carbon emissions, and improving magnesium metallurgical efficiency and the reduction rate of magnesium in magnesium oxide powder. At the same time, it is of great significance for reducing the physical size of magnesium smelting equipment and reducing investment costs, production energy consumption, energy conservation and emission reduction.

[0032] The present invention realizes continuous crystallization by arranging three magnesium vapor collectors to perform condensation, discharging and standby in an alternating cycle in sequence, thereby solving the problem that the existing Pidgeon method is forced to stop production due to the capacity limitation of the magnesium vapor collector, and further improving the magnesium metallurgical efficiency; at the same time, since the solid-liquid interface mixing is a dynamic reaction and the gaseous magnesium can be extracted in time, the pressure on the furnace body caused by the volume expansion generated by the later cooling phase change is significantly reduced, thereby improving the stress environment of the furnace body.

[0033] The present invention can realize centralized collection of slag by opening the cover plate, which not only realizes continuous slag discharge, but also facilitates recovery of heat carried by the slag through heat exchange, which is used for heat preservation of materials in front of the furnace and heating of production water. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 : Schematic diagram of the three-dimensional structure of the high-efficiency and low-carbon vertical tank ultra-gravity mixed magnesium smelting device of the present invention;

[0035] Figure 2 : A schematic diagram of the top view of the structure of the high-efficiency and low-carbon vertical tank ultra-gravity mixed magnesium smelting device of the present invention;

[0036] Figure 3 : The present invention Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle;

[0037] Figure 4 : A partial side structural schematic diagram of the liquid reducing agent atomizing disk of the present invention;

[0038] Figure 5 : A schematic diagram of the structure of the liquid reducing agent atomizing disk of the present invention when viewed from above;

[0039] In the figure: 1. liquid reducing agent feeding pipe; 2. furnace body; 3. liquid-solid mixed reaction tank; 4. heating ring; 5. secondary solid raw material feeding vacuum valve; 6. solid raw material feeding pipe; 7. belt; 8. primary solid raw material feeding vacuum valve; 9. adjustable differential motor; 10. solid raw material dividing plate; 11. liquid reducing agent atomizing disk; 12. magnesium vapor collecting system; 13. vacuum pumping system; 14. vacuum valve; 15. primary gathering cone tube; 16. secondary gathering cone tube; 17. slag outlet; 18. primary liquid reducing agent feeding vacuum valve; 19. secondary liquid reducing agent feeding vacuum valve; 20. driving pulley; 21. driven pulley; 22. hopper. DETAILED DESCRIPTION

[0040] The specific contents of the present invention are further explained in detail below in conjunction with embodiments.

[0041] like Figure 1 to Figure 3 As shown, a high-efficiency low-carbon vertical tank ultra-gravity mixed magnesium smelting device comprises a furnace body 2, an ultra-gravity solid-liquid mixing system, a magnesium vapor collection system 12 and a vacuum system 13;

[0042] The supergravity solid-liquid mixing system includes an adjustable differential motor 9 and a primary material gathering cone tube 15 and a secondary material gathering cone tube 16 fixedly installed inside the furnace body 2, the primary material gathering cone tube 15 is located directly above the secondary material gathering cone tube 16, and a discharge port is opened below the secondary material gathering cone tube 16;

[0043] A liquid-solid mixed reaction tank 3 is provided above the first-level aggregate cone 15, and a vertically arranged solid raw material feeding pipe 6 is fixedly installed on the liquid-solid mixed reaction tank 3. One end of the solid raw material feeding pipe 6 extends into the liquid-solid mixed reaction tank 3 and is connected to a second-level solid raw material feeding vacuum valve 5. The other end of the solid raw material feeding pipe 6 extends out through a hole provided in the furnace body 2 and is connected to a first-level solid raw material feeding vacuum valve 8. The part of the solid raw material feeding pipe 6 located between the first-level solid raw material feeding vacuum valve 8 and the second-level solid raw material feeding vacuum valve 5 forms a vacuum bin for temporarily storing solid raw materials and is connected to a vacuum pumping system 13. The amount of magnesium oxide powder entering the solid raw material feeding pipe 6 can be controlled by the first-level solid raw material feeding vacuum valve 8 and the second-level solid raw material feeding vacuum valve 5. At the same time, the vacuum pumping system 13 is used to evacuate the inside of the vacuum bin to prevent the magnesium oxide powder from bringing air into the furnace body 2.

[0044] A horizontal solid raw material dividing plate 10 is installed inside the liquid-solid mixed reaction tank 3, and a gap is provided between the circumference of the solid raw material dividing plate 10 and the inner wall of the liquid-solid mixed reaction tank 3, and a temporary chamber for accommodating the magnesium oxide powder discharged from the solid raw material feed pipe 6 is formed between the solid raw material dividing plate 10 and the liquid-solid mixed reaction tank 3, so as to prevent a large amount of magnesium oxide powder from being discharged from the solid raw material feed pipe 6 and accumulating on the liquid reducing agent atomizing disk 11, thereby affecting the atomization effect of the liquid reducing agent atomizing disk 11 and causing insufficient reaction;

[0045] The solid raw material feed pipe 6 is rotatably connected to the furnace body 2, a hopper 22 is fixedly installed on the top of the solid raw material feed pipe 6, and one end of the solid raw material feed pipe 6 extending out of the furnace body 2 is fixedly connected to a driven pulley 21; the output shaft of the adjustable differential motor 9 is fixedly connected to a driving pulley 20, and the driving pulley 20 and the driven pulley 21 are connected by a belt 7. When the adjustable differential motor 9 is working, it drives the driving pulley 20 to rotate, thereby driving the driven pulley 2 to rotate through the belt 7, so that the solid raw material feed pipe 6 rotates and drives the liquid-solid mixed reaction tank 3 and the solid raw material dividing plate 10 to rotate, and the magnesium oxide powder is thrown out from the gap between the solid raw material dividing plate 10 and the liquid-solid mixed reaction tank 3;

[0046] The liquid-solid mixed reaction tank 3 is fixedly provided with a liquid reducing agent atomizing disk 11. Figure 5 As shown, six connecting rods are fixedly installed along the radial direction at the bottom of the liquid reducing agent atomizing disk 11, and the six connecting rods are fixed to the inner wall of the liquid-solid mixed reaction tank 3. The liquid reducing agent atomizing disk 11 rotates with the liquid-solid mixed reaction tank 3. Under the action of centrifugal force, the liquid reducing agent is thrown out and becomes tiny reducing agent droplets. The reducing agent droplets and the magnesium oxide powder are mixed and reacted through solid-liquid mixing, which increases the probability and time of oxygen mixing and improves the reduction rate.

[0047] The central position of the liquid reducing agent atomizing disk 11 is rotatably connected with a vertical liquid reducing agent feeding pipe 1, and the liquid reducing agent feeding pipe 1 extends out through holes provided in the liquid-solid mixed reaction tank 3, the first-level aggregate cone tube 15, the second-level aggregate cone tube 16 and the furnace body 2 in sequence, and the hole provided in the liquid-solid mixed reaction tank 3 is larger than the diameter of the liquid reducing agent feeding pipe 1, thereby affecting the rotation of the liquid-solid mixed reaction tank 3 relative to the liquid reducing agent feeding pipe 1, and the liquid reducing agent feeding pipe 1 is fixedly connected to the first-level aggregate cone tube 15, the second-level aggregate cone tube 16 and the furnace body 2;

[0048] The first-stage aggregate cone tube 15 and the second-stage aggregate cone tube 16 can be provided in plurality, and the plurality of first-stage aggregate cone tubes 15 and the second-stage aggregate cone tubes 16 are alternately arranged from top to bottom to form a multi-stage aggregate system, which can further promote the mixing of the unreacted magnesium oxide powder and the liquid reducing agent.

[0049] The liquid reducing agent feeding pipe 1 is connected with a primary liquid reducing agent feeding vacuum valve 18 and a secondary liquid reducing agent feeding vacuum valve 19. The portion of the liquid reducing agent feeding pipe 1 between the primary liquid reducing agent feeding vacuum valve 18 and the secondary liquid reducing agent feeding vacuum valve 19 forms a vacuum chamber for temporarily storing the liquid reducing agent and is connected to a vacuum pumping system 13, so that the amount of the liquid reducing agent entering the liquid reducing agent atomizing disk 11 can be controlled, and waste of the liquid reducing agent can be prevented. At the same time, the vacuum chamber can be vacuumed by the vacuum pumping system 13, so that the liquid reducing agent can be prevented from bringing air into the furnace body 2.

[0050] The liquid reducing agent atomizing disk 16 adopts centrifugal atomization under vacuum; it can also adopt inert and reducing gases such as argon and helium for gas atomization under negative pressure or normal pressure;

[0051] The liquid reducing agent feed pipe 1 and the solid raw material feed pipe 6 are both provided with a heating ring 4, which is used to heat the magnesium oxide powder and the liquid reducing agent, so that the magnesium oxide powder and the liquid reducing agent are kept at high temperatures, so as to react quickly and generate gaseous magnesium element. In addition, the heating ring 4 is arranged inside the furnace body 2, which can reduce heat loss and play a role in energy saving;

[0052] The furnace body 2 is connected to a magnesium vapor collection system 12 through a pipeline. The magnesium vapor collection system 12 includes three magnesium vapor collectors respectively connected to the furnace body 2 through pipelines. The three magnesium vapor collectors are respectively connected to a vacuum pumping system 13, and each pipeline is connected to a vacuum valve 14. The vacuum valve 14 is opened, and with the help of the suction effect of the vacuum pumping system 13, the gaseous magnesium element is fully discharged from the gap between the liquid-solid mixed reaction tank 3 and the first-level aggregate cone tube 15 and the gap between the first-level aggregate cone tube 15 and the second-level aggregate cone tube 16 and is 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.

[0053] A slag outlet 17 is provided at the bottom of the furnace body 2, and the slag outlet 17 is connected to a cover plate by a hinge. A rubber ring for sealing the slag outlet 17 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 17 is sealed by the cover plate and the rubber ring, so that the furnace body 2 is in a closed state. By centrally collecting the slag, not only can the continuous production of magnesium reduction be realized, but also the heat carried by the slag can be recovered through heat exchange, which can be used for the insulation of materials in front of the furnace and the heating of production water, thereby realizing the recovery and utilization of waste heat.

[0054] Preferably, the first-stage conical tube 15 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 15 during the downward sedimentation process.

[0055] Preferably, the secondary aggregation cone 16 is in the shape of a cone with a larger top and a smaller 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.

[0056] Preferably, the upper half of the inner wall of the liquid-solid mixed reaction tank 3 and the outer wall of the part of the solid raw material feed pipe 6 extending into the liquid-solid mixed reaction tank 3 are both provided with crushing nails, and the crushing nails arranged on the inner wall of the liquid-solid mixed reaction tank 3 and the crushing nails arranged on the outer wall of the solid raw material feed pipe 6 are staggered in the horizontal direction, and the spacing between the crushing nails becomes denser and gradually longer from top to bottom. The raw materials are fully dispersed by the crushing nails to prevent the magnesium oxide powder from sticking together due to the viscosity of the liquid reducing agent.

[0057] Preferably, Figure 3 As shown, the upper surface of the liquid reducing agent atomizing disk 11 is provided with a circle of saw teeth along its circumference, through which the droplets thrown out by centrifugal force can be broken up, and a small amount of large particle agglomerates falling on its surface can be punctured to prevent them from clogging the nozzle.

[0058] A high-efficiency and low-carbon vertical tank ultra-gravity mixed magnesium smelting method comprises the following steps:

[0059] Step 1: close the primary solid raw material feeding vacuum valve 8 and the primary liquid reducing agent feeding vacuum valve 18, open the secondary solid raw material feeding vacuum valve 5 and the secondary liquid reducing agent feeding vacuum valve 19 and the vacuum valve 14, use the vacuum pumping system 13 to evacuate the inside of the furnace body 2, wait until the vacuum degree in the furnace body 2 reaches the preset standard, close the secondary solid raw material feeding vacuum valve 5 and the secondary liquid reducing agent feeding vacuum valve 19, load the magnesium oxide powder into the hopper 22, and inject the liquid reducing agent into the liquid reducing agent feeding pipe 1 through the peristaltic pump, Open the first-level solid raw material feeding vacuum valve 8 and the first-level liquid reducing agent feeding vacuum valve 18, wait for the magnesium oxide powder and the liquid reducing agent to enter the vacuum chamber, close the first-level solid raw material feeding vacuum valve 8 and the first-level liquid reducing agent feeding vacuum valve 18, then continue to evacuate until the vacuum degree in the furnace body 2 reaches the preset standard, open the second-level solid raw material feeding vacuum valve 5 and the second-level liquid reducing agent feeding vacuum valve 19, and the magnesium oxide powder and the liquid reducing agent flow into the solid raw material feeding pipe 6 and the liquid reducing agent feeding pipe 1 respectively and are heated by the heating ring 4;

[0060] Step 2, the adjustable differential motor 9 drives the active pulley 20, and the active pulley 20 drives the driven pulley 21 to rotate through the belt 7, so that the solid raw material feed pipe 6 rotates and drives the liquid-solid mixed reaction tank 3 and the solid raw material dividing plate 10 to rotate, and the magnesium oxide powder enters the liquid-solid mixed reaction tank 3 under the action of gravity, and is divided from the gap between the solid raw material dividing plate 10 and the liquid-solid mixed reaction tank 3 under the action of centrifugal force; at the same time, the liquid reducing agent flows from the liquid reducing agent feed pipe 1 into the liquid reducing agent atomizing disk 11 under the action of negative pressure, and is broken into tiny droplets, and the droplets collide and mix with the magnesium oxide powder rapidly, and react while settling downward to generate gaseous magnesium element, and the reaction formula is as follows:

[0061] Si / Al(l)+MgO(s)=Mg(g)↑+SiO2 / Al2O3(s)

[0062] Step 3: During the downward sedimentation, the unreacted magnesium oxide powder, liquid reducing agent and by-products are successively sedimented to the primary aggregate cone 15 and the secondary aggregate cone 16 to mix and react again, and the solid product is discharged from the bottom discharge port of the secondary aggregate cone 16 and falls into the bottom of the furnace body 2, and then discharged from the slag discharge port 17;

[0063] Step 4: Under the suction action of the vacuum system 13, the gaseous magnesium element flows out from the gap between the liquid-solid mixed reaction tank 3 and the first-level gathering cone tube 15 and the gap between the first-level gathering cone tube 15 and the second-level gathering cone tube 16 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.

[0064] The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting 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, calcium silicon, metallic aluminum and aluminum-iron, and has a relatively wide range of applications.

[0065] The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device and method of this embodiment can control the flow rate of solid and liquid through the solid raw material feed vacuum valve and the liquid reducing agent feed 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 can be controlled. Automated production can be achieved by adding temperature sensors, etc., thereby realizing large-scale production.

[0066] Although the high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device of the present embodiment is similar to a vertical furnace, it does not have the relatively static reduction of the pellet pile. Therefore, the external force borne by the furnace body at high temperature is significantly reduced. At the same time, a mixing technology combining centrifugal liquid atomization and centrifugal powder dispersion is adopted to efficiently and evenly mix the reducing agent and magnesium oxide powder, strengthen the reaction process, and replace the relatively static metallurgy of the Pidgeon process vertical furnace with dynamic continuous smelting technology, so that the volume expansion caused by the later cooling phase change of the product significantly reduces the force on the furnace tube, thereby greatly improving the stress environment and conditions of the furnace tube.

[0067] The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device and method of this embodiment can make use of the high energy of the upstream high-temperature reducing agent to react with the heated oxidant; it can also design a magnesium metallurgical industrial park, and use the waste heat from the upstream roasting of magnesium oxide minerals, the waste heat from the smelting of reducing agents such as ferrosilicon, metallic aluminum, calcium silicon, ferroaluminum, and waste silicon powder for magnesium metallurgical liquid-solid reduction, and then utilize the subsequent waste heat from the refining of raw magnesium. Through energy combination, the energy consumption, carbon emissions and efficiency of the entire process can be optimized, thereby building a low-energy magnesium industrial park and creating a world-class magnesium metallurgical industrial line.

[0068] The high-efficiency and low-carbon vertical tank ultra-gravity mixed magnesium smelting device and method of this embodiment transforms the solid-solid heat transfer and value transfer of traditional Pidgeon process magnesium smelting into liquid-solid heat transfer mechanism, and adopts ultra-gravity assisted enhanced mixing, which significantly improves the heat and mass transfer efficiency, thereby improving the reaction efficiency. The liquid droplets atomized by the molten liquid and the powder curtain formed by powder dispersion and sedimentation are confronted, contacted and coated, thereby realizing rapid mixing and subsequent convergence and dispersion flow, 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 relatively static point-line contact reduction of traditional Pidgeon process. In addition, considering Due to the influence of the viscosity of the liquid phase itself and the adhesion between the remaining 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 and solid 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 reducing agent and the solid-phase oxidizing agent by controlling the mixing speed, thereby improving the reaction efficiency and reduction efficiency.

[0069] In summary, the high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device and method of this embodiment achieves effective energy saving through the following three ways: first, micro energy saving, converting solid-solid reaction into liquid-solid reaction to reduce reaction energy consumption; second, monomer energy saving, centralized collection of slag, and setting heat recovery pipelines at the bottom of the furnace shell, etc., using the heat exchange system to achieve waste heat recovery and utilization, so as to reduce the energy consumption of the metallurgical process, and at the same time, complete the continuous slag discharge; third, system comprehensive energy saving, which 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 for 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 high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device, characterized in that: It comprises a furnace body (2), an ultra-gravity solid-liquid mixing system, a magnesium vapor collection system (12) and a vacuum pumping system (13); The supergravity solid-liquid mixing system comprises a transmission assembly and a primary material gathering cone tube (15) and a secondary material gathering cone tube (16) fixedly installed inside a furnace body (2), wherein the primary material gathering cone tube (15) is located directly above the secondary material gathering cone tube (16), and a discharge port is provided below the secondary material gathering cone tube (16); A liquid-solid mixed reaction tank (3) is provided above the first-stage aggregate cone tube (15), a horizontal solid raw material dividing plate (10) is installed inside the liquid-solid mixed reaction tank (3), and a gap is provided between the circumference of the solid raw material dividing plate (10) and the inner wall of the liquid-solid mixed reaction tank (3); a vertical solid raw material feeding pipe (6) is fixedly installed on the liquid-solid mixed reaction tank (3), and the solid raw material feeding pipe (6) is connected to a solid raw material feeding vacuum valve, one end of the solid raw material feeding pipe (6) extends into the liquid-solid mixed reaction tank (3), and the other end of the solid raw material feeding pipe (6) extends out through a hole provided in the furnace body (2) and is rotatably connected thereto, and the solid raw material feeding pipe (6) is connected to a transmission component capable of driving it to rotate, and a hopper (22) is fixedly installed on the top of the solid raw material feeding pipe (6); A liquid reducing agent atomizing disk (11) is fixedly installed inside the liquid-solid mixed reaction tank (3), and the liquid reducing agent atomizing disk (11) is rotatably connected to a vertical liquid reducing agent feeding pipe (1). The liquid reducing agent feeding pipe (1) extends out through holes provided in the liquid-solid mixed reaction tank (3), the first-level material gathering cone tube (15), the second-level material gathering cone tube (16) and the furnace body (2) in sequence and is connected to a liquid reducing agent feeding vacuum valve. The diameter of the hole provided in the liquid-solid mixed reaction tank (3) is larger than the diameter of the liquid reducing agent feeding pipe (1), so that the liquid-solid mixed reaction tank (3) can rotate relative to the liquid reducing agent feeding pipe (1). The liquid reducing agent feeding pipe (1) is fixedly connected to the first-level material gathering cone tube (15), the second-level material gathering cone tube (16) and the furnace body (2); The solid raw material feed pipe (6) and the liquid reducing agent feed pipe (1) are both provided with a heating ring (4); the furnace body (2) is connected to a magnesium vapor collection system (12) through a pipeline, the magnesium vapor collection system (12) is connected to a vacuum pumping system (13), and a slag outlet (17) is provided at the bottom of the furnace body (2), and the slag outlet (17) is connected to a sealing member.

2. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device according to claim 1 is characterized in that: The transmission assembly comprises an adjustable differential motor (9) and a driven pulley (21) fixedly connected to a solid raw material feed pipe (6); the output shaft of the adjustable differential motor (9) is fixedly connected to a driving pulley (20); and the driving pulley (20) and the driven pulley (21) are connected via a belt (7).

3. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device according to claim 1 or 2, characterized in that: The relative positions of the inner wall of the liquid-solid mixed reaction tank (3) and the outer wall of the solid raw material feeding pipe (6) are provided with crushing nails staggered in the horizontal direction, the length of the crushing nails gradually increases from top to bottom, and the vertical distance between two adjacent crushing nails gradually decreases.

4. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting 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 (8) and a secondary solid raw material feeding vacuum valve (5) respectively connected to a solid raw material feeding pipe (6); a portion of the solid raw material feeding pipe (6) located between the primary solid raw material feeding vacuum valve (8) and the secondary solid raw material feeding vacuum valve (5) forms a vacuum bin for storing solid raw materials and is connected to a vacuum pumping system (13).

5. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting 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 (18) and a secondary liquid reducing agent feeding vacuum valve (19); the portion of the liquid reducing agent feeding pipe (1) located between the primary liquid reducing agent feeding vacuum valve (18) and the secondary liquid reducing agent feeding vacuum valve (19) forms a vacuum chamber for storing the liquid reducing agent and is connected to a vacuum pumping system (13).

6. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device according to claim 5 is characterized in that: The magnesium vapor collection system (12) comprises three magnesium vapor collectors respectively connected to the furnace body (2) through pipelines, the three magnesium vapor collectors are respectively connected to the vacuum pumping system (13), and the pipelines are connected to vacuum valves (14).

7. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device according to claim 1 or 2, characterized in that: The upper surface of the liquid reducing agent atomizing disk (11) is provided with a circle of saw teeth along its circumference.

8. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting device according to claim 1 or 2, characterized in that: The sealing member is a cover plate connected to the slag outlet (17) via a hinge, and a rubber ring for sealing the slag outlet (17) is fixedly installed around the circumference of the cover plate.

9. A high-efficiency low-carbon vertical tank ultra-gravity mixed magnesium smelting method based on the high-efficiency low-carbon vertical tank ultra-gravity mixed magnesium smelting device according to claim 6, characterized in that: The steps include: Step 1: close the primary solid raw material feeding vacuum valve (8) and the primary liquid reducing agent feeding vacuum valve (18), open the secondary solid raw material feeding vacuum valve (5) and the secondary liquid reducing agent feeding vacuum valve (19), use the vacuum pumping system (13) to evacuate the inside of the furnace body (2), wait until the vacuum degree in the furnace body (2) reaches a preset standard, close the secondary solid raw material feeding vacuum valve (5) and the secondary liquid reducing agent feeding vacuum valve (19), load magnesium oxide powder into the hopper (22), and inject liquid reducing agent into the liquid reducing agent feeding pipe (1) through a peristaltic pump, open the primary The solid raw material feeding vacuum valve (8) and the first-level liquid reducing agent feeding vacuum valve (18) are closed after the magnesium oxide powder and the liquid reducing agent enter the vacuum chamber, and then the vacuum is continuously drawn until the vacuum degree in the furnace body (2) and the vacuum chamber reaches a preset standard, and the second-level solid raw material feeding vacuum valve (5) and the second-level liquid reducing agent feeding vacuum valve (19) are opened, and the magnesium oxide powder and the liquid reducing agent flow into the solid raw material feeding pipe (6) and the liquid reducing agent feeding pipe (1) respectively and are heated by the heating ring (4); Step 2, the adjustable differential motor (9) drives the driving pulley (20), and the driving pulley (20) drives the driven pulley (21) to rotate through the belt (7), so that the solid raw material feeding pipe (6) rotates and drives the liquid-solid mixed reaction tank (3) and the solid raw material dividing plate (10) to rotate, and the magnesium oxide powder enters the liquid-solid mixed reaction tank (3) under the action of gravity, and is divided from the gap between the solid raw material dividing plate (10) and the liquid-solid mixed reaction tank (3) under the action of centrifugal force; at the same time, the liquid reducing agent flows from the liquid reducing agent feeding pipe (1) into the liquid reducing agent atomizing disk (11) under the action of negative pressure and is thrown out under the action of centrifugal force to become tiny droplets, and the droplets quickly collide and mix with the magnesium oxide powder, and react while settling downward to generate gaseous magnesium element; Step 3: During the downward sedimentation process, the unreacted magnesium oxide powder, liquid reducing agent and by-products are successively sedimented to the primary aggregate cone tube (15) and the secondary aggregate cone tube (16) to be mixed and reacted again, and the solid product is discharged from the bottom discharge port of the secondary aggregate cone tube (16) and falls into the bottom of the furnace body (2), and then discharged from the slag discharge port (17); Step 4: Under the suction action of the vacuum system (13), gaseous magnesium flows out from the gap between the liquid-solid mixed reaction tank (3) and the first-stage aggregate cone tube (15) and the gap between the first-stage aggregate cone tube (15) and the second-stage aggregate cone tube (16) and is collected in a magnesium vapor collector. After condensation and crystallization, raw magnesium is obtained.

10. The high-efficiency, low-carbon vertical tank ultra-gravity mixed magnesium smelting method according to claim 9 is 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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