CN114293014B - Silicon carbide-free thermal reduction magnesium metallurgy device and method - Google Patents

Abstract

A silicon carbide-free thermal reduction magnesium metallurgy device and a method. Aiming at the heavy pressure of double carbon and double control targets of the iron alloy industry and the magnesium metallurgy industry, the aim of non-carbonization of magnesium metallurgy is fulfilled by cooperatively connecting material flow and energy flow between the two industries and using a silicon alloy superheated energy as a magnesium metallurgy reduction energy. Namely, the invention adopts molten silicon alloy to reduce MgO, and finishes the MgO reduction process when excessive (the silicon/oxygen ratio is more than or equal to 1.5) silicon alloy is overheated (the temperature is higher than 1300 ℃ melting point temperature of 75FeSi and is more than 300 ℃) by adjusting the MgO reaction amount; the molten state of the silicon alloy is kept, the magnesium metallurgy process is facilitated to replace the reaction between a Pidgeon process solid phase (silicon alloy) and a solid phase (MgO) through the reaction between a liquid phase (silicon alloy) and the solid phase (MgO), particularly, a liquid phase wrapping solid phase reaction structure is formed through molten metal atomization, the heat transfer, mass transfer and energy transfer between the two phases are enhanced, the reduction efficiency is improved, the energy consumption of the magnesium metallurgy is greatly reduced, and meanwhile, the carbonization-free process is realized.

Description

A kind of non-silicon carbide thermal reduction magnesium metallurgical device and method

technical field

The invention relates to a magnesium metallurgical preparation method, in particular to a silicon carbide-free thermal reduction magnesium metallurgical device and method.

Background technique

Magnesium metal and its alloys have the advantages of high specific strength, good thermal and electrical conductivity, damping and shock absorption, electromagnetic external shielding, easy machining and easy recycling. They are widely used and have become the third largest metal after steel and aluminum. Engineering Materials. In 2017, the world's magnesium metal production has exceeded 1.2 million tons. my country is the world's largest producer of magnesium, accounting for more than 85% of the world's total output. In China, all raw magnesium metal is produced by the Pidgeon method. The Pidgeon method is a vacuum thermal reduction magnesium smelting technology using dolomite as raw material and 75% silicon-containing ferrosilicon alloy (75# ferrosilicon) as reducing agent. The Pidgeon method has a history of more than 70 years since its birth, and has been used in my country for more than 40 years. After decades of development, especially the application of regenerative reduction furnaces in the past ten years, the energy consumption has been reduced from 10t of standard coal to 10t of standard coal for the production of 1t of magnesium to 4-5t. If the energy consumption of the reducing agent ferrosilicon is added, the comprehensive energy consumption of the Pidgeon magnesium smelting technology is still as high as 8-9 tons of standard coal, and the unit energy consumption even exceeds that of metal aluminum. It is one of the non-ferrous metallurgical industries with the highest unit energy consumption. The magnesium metallurgy industry, which is dominated by petrochemical energy, is also one of the main forces of carbon dioxide emissions. According to the statistics of the China Nonferrous Metals Industry Association, the national magnesium output in 2019 was more than 840,000 tons, and the carbon dioxide emissions were about 13.75-14.98 million tons, accounting for about 13-15% of the country's carbon dioxide emissions that year. With the mandatory advancement of the national "dual carbon" target and the general requirements for the dual control of energy consumption, magnesium metallurgy and the "two high" industries represented by ferrosilicon alloys and large CO ₂ emitters are facing serious survival crisis. How to greatly save energy and reduce carbon is the key to the survival and development of Pidgeon magnesium metallurgy.

Pidgeon magnesium metallurgy is to reduce the pellets made of roasted white jade, 75 ferrosilicon alloy, fluorite and calcium oxide at a vacuum of 10pa and 1200℃. Due to the poor thermal conductivity of the pellets, the low efficiency of the solid-solid reaction itself, and the continuous decline of the magnesium vapor overflow efficiency, the reduction time is as long as 8-12 hours, the energy consumption is large, and the reduction rate of MgO is less than 80%. Similarly, as a reducing agent for magnesium metallurgy, the smelting of silicon-based alloys is to reduce the carbon source, quartz stone and iron source mixture in a submerged arc furnace in a molten state formed by arc heating. The temperature is about 1800 ℃ or more, and the molten iron outlet Up to 1700 ℃ or more. All ferroalloys, including silicon-based alloys, are basically cast in pits due to the forming process. The heat of dissolution and solidification cannot be recovered, resulting in high energy consumption in the ferroalloy industry.

In Pidgeon magnesium metallurgy, silicon-based alloys are only used as reducing agents for magnesium metallurgy. The metallurgical temperature of magnesium is above 900 °C, the melting point of silicon is 1410 °C, and the melting point of ferrosilicon alloy is between 1200-1400 °C. Among them, the main melting point of 75FeSi is 1300 °C. If silicon-based alloys are used as the heat source for magnesium smelting, the energy cost of magnesium smelting will be significantly reduced. To be precise, using the heat at the outlet of molten silicon-based alloys from 1750 °C to 1300 °C, as a heat source for magnesium metallurgical reduction, will greatly realize the recovery and reuse of heat from silicon-based alloys, and realize the development of silicon-based alloy industry and magnesium. Metallurgical industry "dual control" and "dual carbon" goals.

Silicon alloys belong to the ferroalloy industry, which has long been plagued by the characterization of "high energy consumption and high pollution". The industry has also continued to do a lot of work in large-scale equipment, industrial process automation and production lean, and the production capacity of a single equipment and the level of continuous and automatic control have been significantly improved. In terms of energy saving, breakthroughs have also been made in the waste heat of flue gas, the recovery of combustible gas in flue gas, and the utilization of waste heat from waste residues, and energy consumption has been significantly reduced. However, since the ferroalloy forming is mainly static forming, the existing forming technology cannot meet the requirements of planned production, and almost all the solidification heat of the ferroalloy is consumed. This is the part where the ferroalloy loses the most heat energy. But since the birth of ferroalloys, no key changes have been made.

The Pidgeon magnesium smelting process has significant advantages in the existing magnesium metallurgy technology, such as small investment, convenient operation and large-scale production. nation. Its significant cost advantage has also become a weapon for China's magnesium to occupy 85% of the world's market. It has laid a solid economic foundation for the widespread use of magnesium alloys in the world. Focusing on the problems existing in the magnesium smelting process by the Pidgeon method, relevant domestic institutes have carried out various researches. For example, the magnesium-metallurgical integration technology carried out by Zhang Ting'an's team of Northeastern University, which integrates dolomite calcination and reduction; Wang Xiaogang of Xi'an University of Technology invented A multi-heat source internal heat magnesium smelting device has been established, and a new large-scale shaft furnace magnesium smelting process has been established; Shaanxi Fugu follows the development idea of "centralized layout, green production, project grouping, industrial circulation, and park bearing", but it has not changed. The essence of Pidgeon's reduction. Other personnel have carried out certain work on the magnesium reduction shaft furnace, and have made certain progress, but have not broken through the technical scope of Pidgeon magnesium smelting. Because of this, with the mandatory implementation of the "dual carbon" target, the Pidgeon-method magnesium metallurgical industry characterized by "high energy consumption, high pollution, and high emissions" will surely become the primary control target. The world supply of magnesium metal will face serious challenges.

There are still the following problems in the Pidgeon process of magnesium smelting. First, the energy consumption is high, smelting 1 ton of metal magnesium requires 4-5 tons of standard coal, and the energy consumption of ferrosilicon alloy smelting, the energy consumption per ton of primary magnesium reaches 8-9 tons of standard coal; second, the reduction rate is low, the current MgO The reduction rate is less than 80%; the third is low efficiency, and the reduction time is as long as 8-12 hours; the third is pollution, the waste residue produced by the reduction and the fluorite added in the reaction are both sources of pollution; and the impact of the short life of the reduction tank on production, etc. question.

In fact, there are two fundamental reasons for the above problems of Pidgeon magnesium smelting. First, the reduction pellet is a solid-phase reaction, and the contact of the reactants is insufficient, especially the mass transfer efficiency of the reaction rate is further attenuated with the overflow of magnesium vapor, resulting in an incomplete reaction; second, the heat transfer efficiency is low. Whether it is an internal heating type or an external heating type, the components contained in the reaction pellets are mainly calcined dolomite, ferrosilicon alloy, fluorite and calcium oxide. These components are all poor conductors with low thermal conductivity, which makes it difficult to transfer heat inside and outside the pellets and between each other, which in turn leads to long reduction time, low reaction efficiency, and problems of reduction tank volume and production capacity. In this context, the addition of the mineralizer fluorite helps to speed up the reduction efficiency, but causes hydrogen fluoride gas pollution. It can be seen that the key to realizing energy saving in magnesium metallurgy is to improve the heat transfer and reaction efficiency of reactants. It is well known that from the point of view of reaction efficiency, gas-solid>liquid-solid>solid-solid. Therefore, if the solid-solid reaction in the magnesium reduction process can be converted into a liquid-solid reaction, the heat transfer and reaction efficiency will be greatly enhanced. According to this idea, this goal can be achieved by using the reducing agent in the magnesium reduction process-silicon alloy to participate in the reduction of MgO in the liquid phase.

Silicon alloys are in the liquid phase when smelting and tapping, and the tapping temperature is generally required to be above 1600 °C, which is much higher than the reduction reaction temperature of 900-1200 °C for magnesium pellets made by Pidgeon. The reaction between the liquid-phase silicon-based iron alloy and solid-state MgO at such a high temperature will significantly enhance the heat transfer efficiency, significantly improve the reduction efficiency of MgO, and there is no need to use a vacuum method to improve the reaction efficiency and reduce the reduction temperature, and then to normal pressure or negative pressure magnesium. Metallurgy creates process conditions. After the magnesium vapor reduced by silicothermic reduction overflows, the silicon-based alloy solution will replenish the gap left by the gas overflow in time, and always maintain close contact with the remaining MgO particles to maintain continuous heat transfer and reduction efficiency. Therefore, there is also no need to add fluorite as a mineralizer. HF gas pollution is eliminated.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of silicon carbide-free thermal reduction magnesium metallurgy device and method which can realize high efficiency, low carbon, energy saving and greening of magnesium metallurgy process.

In order to achieve the above object, the present invention provides a silicon carbide-free thermal reduction magnesium metallurgical device, comprising an upper molten silicon-based ferroalloy furnace, a middle reduction furnace and a lower slag refining furnace connected in sequence;

The upper end of the molten silicon-based ferroalloy furnace is provided with a molten-silicon-based ferroalloy feeding pipeline, a heating wire device is installed inside, and a molten-silicon-based ferroalloy outlet communicated with the middle reduction furnace is opened at the lower end. Lifting rod, the lower end of the lifting rod passes through the outlet of molten silicon-based iron alloy, and an atomizing nozzle communicated with the reduction furnace is installed around the outlet of molten silicon-based iron alloy. The fluidized bed is connected, and the fluidized bed is also provided with a high-pressure argon gas inlet;

The middle reduction furnace includes an outer shell and a reduction furnace sheathed in the outer shell. The upper end of the reduction furnace is communicated with the molten silicon-based iron alloy outlet and the atomizing nozzle, and a gap is left between the lower end and the lower end of the outer shell. A magnesium vapor zone is formed, a condensation and crystallization device is installed outside the shell, and the slag outlet at the lower end of the shell is communicated with the lower slag refining furnace;

The lower slag refining furnace is installed on the support material, the upper end of the slag refining furnace is communicated with the slag outlet at the lower end of the shell, the bottom end side wall is provided with a tap hole pipe that communicates with the pouring treatment equipment, and the upper end side wall is provided with an outlet pipe. The slag port pipeline is provided with an exhaust pipe and a rotary injection device at the top. The inlet of the rotary injection device is connected to the argon inlet pipeline. The lower end of the rotary injection device extends into the bottom of the slag refining furnace, and is located at the bottom of the rotary injection device. A graphite rotor is installed.

The molten silicon-based ferroalloy furnace is made of thermal insulation material, the lower end of the molten silicon-based ferroalloy furnace is a conical structure, and a molten silicon-based ferroalloy feeding pipeline valve is provided on the molten silicon-based ferroalloy feeding pipeline.

A heater is installed on the pipeline connecting the atomizing nozzle with the fluidized bed.

A heating wire device is installed in the outer casing, a high temperature thermocouple is arranged in the reduction furnace, the upper end of the outer casing and the reduction furnace are both bell-shaped structures, and the lower end of the outer casing is installed with a conical structure formed of refractory materials.

The inner wall of the casing is provided with a suspension fixing device, and the reduction furnace is suspended in the casing through the suspension fixing device.

A slag outlet valve is installed on the slag outlet.

The slag refining furnace is composed of an outer thermal insulation material and an inner refractory material, and a heating wire device is arranged between the thermal insulation material and the inner refractory material.

The exhaust pipeline and the argon gas inlet pipeline are respectively provided with an exhaust pipeline valve and an argon gas inlet pipeline valve.

The tap outlet pipeline and the slag outlet pipeline are respectively installed with a tap hole pipeline valve and a slag outlet pipeline valve, and a tap hole pipeline valve and a pipe at the rear end of the slag outlet pipeline valve are respectively installed with a tap hole. Siphon device and slag siphon.

The method for thermally reducing magnesium metallurgy without silicon carbide of the present invention comprises the following steps:

1) The high-temperature molten silicon-based iron alloy enters the molten silicon-based iron alloy furnace through the feeding pipeline, and is maintained at 1700-1800 ℃ under the combined action of the heating wire device and the wrapped insulation material;

2) Through the up and down operation of the pulling rod, the molten silicon-based iron alloy is controlled to enter the intermediate reduction furnace area. At the same time, the dolomite that has been calcined at high temperature, that is, the calcined white powder enters the fluidized bed and the high-pressure argon gas inlet. The high-pressure argon gas is fully mixed, and the mixed gas-solid powder passes through the heater to reach the required high temperature condition. The molten silicon-based iron alloy is formed by wrapping the solid calcined white powder, that is, a large number of spray-like liquid-phase silicon-based alloy wrapping solid-phase powder droplets are formed, which enter the high-temperature reduction zone in the middle for reduction metallurgy of magnesium metal;

3) The liquid-phase silicon-based alloy wraps the solid-phase powder droplets to react at a temperature of 1450-1800 °C, wherein the heating wire device regulates the reaction temperature, and the reaction formula is:

2MgO(s)+Si(Fe)(l)=2Mg(g)+SiO2(s)

SiO2(s)+2CaO(s)=2CaO·SiO2(l)

The generated high temperature magnesium vapor moves downward under the combined action of gravity and the pressure of the upper argon gas and the magnesium vapor gas generated in the reaction. Due to the low density, it will overflow from the lower edge of the reduction chamber and return upward from the magnesium vapor area, and finally enter the condensation crystallization device to form crystalline magnesium when it is condensed;

4) The SiO2 generated during the reaction is wrapped in the silicon-based alloy liquid. Under the action of gravity, together with 2CaO·SiO2 and iron that has not participated in the reaction, the slag of the high-temperature product falls into the slag refining furnace from the slag outlet through the slag outlet valve. middle;

5) Under the protection of internal refractory materials, the lower refining furnace is provided with a heating wire device to ensure that the temperature of the refining furnace is above 1350, the ferroalloy is located in the lower part of the refining furnace, and the oxide slag is located in the upper part of the refining furnace, using the end of the rotary injection device The graphite rotor is at the bottom of the melting pool of the refining furnace. Under the control of the argon inlet pipe valve, argon gas is blown into the argon gas inlet pipe, and the generated fine argon bubbles stir the melt during the floating process, driving light weight oxidation. The material impurities float up and promote the separation of impurities, that is, the slag melt is purified, and the various components in it are mixed evenly;

6) After the slag in the refining furnace has accumulated to the depth set by the refining furnace, open the valve of the slag outlet pipeline, and the oxide slag in the refining furnace will be discharged to the outside of the furnace through the slag outlet pipeline under the action of the siphon for refining. After the height of the silicon-based ferroalloy solution in the furnace reaches 40-50% of the refining furnace capacity, open the tap pipe valve, and discharge it through the tap pipe under the action of the siphon to the intermediate pouring treatment equipment for subsequent ferroalloy treatment and utilization , and still keep the molten iron pool of 10-20% of the furnace capacity in the refining furnace, and an exhaust pipe valve is designed at the top of the melting furnace to control the pressure in the furnace.

The invention aims at realizing the energy recovery of silicon alloys and the energy utilization of magnesium metallurgy through the synergistic connection of materials and energy between the two industries under the heavy pressure of "dual carbon" and "dual control" in the ferroalloy industry and the magnesium metallurgy industry. Achieve the energy-saving and carbon-reduction goals of two high-energy-consuming industries. That is, the present invention adopts molten silicon-based alloy to reduce MgO, and by adjusting the amount of MgO reaction, the MgO reduction process is completed in excess (silicon/oxygen ratio ≥1.5) overheating of silicon-based alloy (temperature higher than 1300 ℃ melting point temperature of 75FeSi by 300 ℃ or more). ;

Maintaining the molten state of the silicon-based alloy helps the magnesium metallurgical process to replace the Pidgeon solid-phase (silicon-based alloy) with the solid-phase (MgO) reaction by the reaction of the liquid phase (silicon-based alloy) and the solid-phase (MgO). It has less influence on the production of silicon alloys. Through the close connection of the logistics and energy flow in the two process flows of silicon alloy and magnesium metallurgy, the molten state of silicon alloy is maintained, especially through the atomization of molten metal, a liquid phase wrapped solid phase reaction structure is formed, which strengthens the two The heat transfer, mass transfer and energy transfer between phases can improve the reduction efficiency, greatly reduce the energy consumption of magnesium metallurgy, and at the same time realize the non-carbonization process, and realize the high efficiency, low carbon, energy saving and green preparation of magnesium metallurgy process.

The technical effects brought by the above solutions are as follows:

1. Energy saving. Basically eliminate the energy consumption of magnesium metallurgy process, that is, 4-5 tons of standard coal per ton of raw magnesium, and achieve energy saving of more than 90%;

2. Carbon-free. The innovative carbon-free reduction metallurgical technology can effectively reduce the carbon emissions of the magnesium metallurgy industry. As the largest carbon dioxide emission industry in China, magnesium metallurgy accounts for more than 12% of China's carbon emissions;

3. Efficient. The reduction of magnesium by the Pidgeon method generally takes 8-12 hours. The invention strengthens heat transfer and mass transfer by means of high temperature and liquid-solid wrapping form, and realizes the transition from long-term to instantaneous magnesium metallurgical reaction process;

4. High reduction rate. The Pidgeon method adopts the solid-solid reaction between materials with low thermal conductivity, and the reduction rate of MgO is less than 80%. The present invention wraps the solid-phase MgO form with excess high-temperature liquid-phase reducing agent, and the reduction rate is increased to more than 95%;

5. Eliminate HF pollution. Fluorite is used as a mineralizer for magnesium smelting in the Pidgeon process, and the addition amount is generally about 3%. Fluorite forms HF gas at high temperature, which causes environmental pollution. The present invention does not need to add fluorite raw material.

6. Realize the large-scale, continuous and large-scale production of magnesium metallurgy. As the main process of China's magnesium metallurgy, Pidgeon process has always been a batch production of multi-layer multi-row small reduction tanks, with low efficiency, high energy consumption and poor environment. The present invention can realize continuous, large-scale and low-carbon manufacturing through high-temperature reduction and high-efficiency reaction under normal pressure.

Description of drawings

FIG. 1 is a schematic structural diagram of a silicon carbide-free thermal reduction magnesium metallurgical device of the present invention.

Among them, 1. molten silicon-based ferroalloy feeding pipeline valve; 2. molten silicon-based ferroalloy feeding pipeline; 3. pulling rod; 4. molten silicon-based ferroalloy furnace; 5. heating wire device; 6. molten silicon-based ferroalloy; 7. heating 8. Calcined white powder (including MgO, CaO); 9. Fluidized bed; 10. High pressure argon inlet; 11. Condensing and crystallization device; 12. Suspension fixing device; 13. High temperature thermocouple; 14. Argon Gas inlet pipeline; 15. Argon gas inlet pipeline valve; 16. Rotary injection device; 17. Slag outlet pipeline valve; 18. Siphon; 19. Slag outlet pipeline; 20. Slag; 21. Pouring processing equipment; 22, siphon device; 23, tap hole pipe; 24, tap hole pipe valve; 25, silicon-containing ferroalloy water; 26, support material; 27, refractory material; 28, heating wire device; 29, thermal insulation material; 30 , slag outlet valve; 31, exhaust pipe valve; 32, exhaust pipe; 33, slag outlet; 34, refractory material; 35, reduction furnace; 36, magnesium vapor area; 37, heating wire device; 38, shell; 39 , Suspension fixed device; 40, liquid silicon alloy wraps solid phase powder droplets; 41, atomizing nozzle.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, the preparation device of the present invention comprises an upper molten silicon-based iron alloy furnace, a middle reduction furnace and a lower slag refining furnace which are connected in sequence;

The molten silicon-based ferroalloy furnace 4 is made of heat-insulating material, and its upper end is provided with a molten-silicon-based ferroalloy feeding pipeline 2 with a molten silicon-based ferroalloy feeding pipeline valve 1, a heating wire device 5 is installed inside, and the lower end is tapered. Structure and the lower end is provided with a molten silicon-based iron alloy outlet that communicates with the middle reduction furnace 35, a pulling rod 3 is installed through the molten silicon-based iron alloy furnace 4, and the lower end of the pulling rod 3 passes through the molten silicon-based iron alloy outlet, and is melted. An atomizing nozzle 41 communicated with the reduction furnace 35 is installed around the outlet of the silicon-based iron alloy. The atomizing nozzle 41 passes through the pipeline and the heater 7 installed on the pipeline and the fluidized bed 9 where the calcined white powder 8 is placed. Connected, the fluidized bed 9 is also provided with a high-pressure argon inlet 10;

The middle reduction furnace includes an outer shell 38 and a reduction furnace 35 sheathed in the outer shell 38. The inner wall of the outer shell 38 is provided with hanging fixing devices 12 and 39. A heating wire device 37 is installed in the 38, a high-temperature thermocouple 13 is installed in the reduction furnace 35, the outer casing 38 and the upper end of the reduction furnace 35 are both flared structures, and the upper end of the reduction furnace 35 is connected with the molten silicon-based iron alloy outlet and the atomizing nozzle 41. There is a gap between the lower end and the lower end of the outer casing 38. The lower end of the outer casing 38 is installed with a conical structure formed by the refractory material 34. The cavity between the outer casing 38 and the reduction furnace 35 forms a magnesium vapor zone 36. Crystallization device 11, the slag outlet 33 at the lower end of the shell is communicated with the lower slag refining furnace;

The lower slag refining furnace is installed on the support material 26, the slag refining furnace is composed of an outer heat insulating material 29 and an inner refractory material 27, and a heating wire device 28 is arranged between the heat insulating material 29 and the inner refractory material 27, The upper end of the slag refining furnace is connected with a slag outlet valve 30 and a slag outlet 33 at the lower end of the shell, a tap hole pipe 23 connected to the pouring treatment equipment 21 is opened on the side wall of the bottom end, and a slag outlet pipe is opened on the side wall of the upper end. 19. The top end is provided with an exhaust pipe 32 with an exhaust pipe valve 31 and a rotary blowing device 16, and the tap hole pipe 23 and the slag outlet pipe 19 are respectively installed with a tap hole pipe valve 24 and a slag outlet pipe valve. 17, and the inlet of the rotary injection device 16 described in the tap siphon device 22 and the slag tap syphon 18 and the inlet with argon gas are respectively installed on the pipes at the rear end of the tap port pipeline valve 24 and the slag tap pipeline valve 17. The argon inlet pipeline 14 of the pipeline valve 15 is connected, the lower end of the rotary blowing device 16 extends into the bottom of the slag refining furnace, and a graphite rotor is installed at the lower end of the rotary blowing device 16 .

The non-silicon carbide thermal reduction magnesium metallurgical method of the present invention comprises the following steps:

Upper part area: The high temperature molten silicon-based iron alloy 6 is controlled by the molten silicon-based iron alloy feeding pipeline valve 1, and enters the molten silicon-based iron alloy furnace 4 from the molten silicon-based iron alloy feeding pipeline 2 in the upper part. Under the joint action of thermal insulation materials, it maintains the high temperature conditions that meet the reduction reaction, and the high temperature is 1800 degrees. Through the up and down operation of the pulling rod 3, the molten silicon-based iron alloy can be controlled to enter the intermediate reduction furnace area. The high-pressure argon gas entering the inlet 10 is fully mixed, and the mixed gas-solid powder passes through the heater 7 to reach the required high temperature condition. The flow tube enters the atomization area and interacts with the core calcined white powder 8 and the high-speed two-phase flow of the atomizing gas argon, and the molten metal forms a liquid film of equal thickness on the powder surface and rapidly solidifies to obtain the form of metal-coated powder, that is, the formation of The solid-phase powder droplet 40 is encapsulated by a large amount of spray-like liquid-phase silicon-based alloy. Enter into the middle high temperature reduction zone to carry out the reduction metallurgy of magnesium metal.

The intermediate reduction area: the liquid-solid encapsulated droplets start to react in a high temperature environment, with a temperature range of 1450-1700 degrees. Among them, the function of the heating wire device is to ensure that the temperature is within an appropriate range. The reduction furnace 35 is suspended in the middle reaction device under the combined action of the suspension fixing devices 12.39 on the left and right sides. The reaction formula is:

2MgO(s)+Si(Fe)(l)=2Mg(g)+SiO2(s)

SiO2(s)+2CaO(s)=2CaO·SiO2(l)

The generated high-temperature magnesium vapor moves downward under the pressure of the upper end, and the surrounding of the reduction furnace 35 is sealed, and the lower part is not sealed. After leaving the reduction furnace 35 from the lower part, due to the low density and high temperature, it turns upward from the magnesium vapor zone 36 and enters the condensing and crystallization device 11 on both sides of the device, because it is condensed into crystalline magnesium.

The middle area and the lower area are refractory materials 34, which play a safety function of fire resistance and a certain supporting effect.

Lower part of the area: The SiO2 generated during the reaction process is wrapped in the silicon-based alloy liquid, and under the action of gravity, together with 2CaO·SiO2 and iron that has not participated in the reaction, the slag of the high-temperature product is controlled by the slag outlet valve, and the slag outlet is controlled by the slag outlet. 33 falls into the slag refining furnace.

Under the protection of the inner refractory material 27, the lower refining furnace is provided with a heating wire device 28 on the outer layer to ensure that the temperature in the furnace is about 1500°C. The lower support material 26 ensures the stability and safety of the overall equipment. The separation occurs because the densities of the iron alloy and the above-mentioned oxide impurities are quite different. The ferroalloy is located in the lower part of the refining furnace, and the oxide slag is located in the upper part of the molten pool. Using the graphite rotor at the end of the rotary blowing device 16 at the bottom of the molten pool, under the control of the argon gas inlet pipe valve 15, argon gas is blown into the argon gas inlet pipe 14, and the generated fine argon bubbles are blown to the melt during the floating process. The stirring action drives the light oxide impurities to float up and promotes the separation of impurities, that is, the slag melt is purified, and the various components in it are mixed evenly, which is convenient for the next step of standing and stratification. When the slag 20 in the furnace is accumulated to a certain depth in the furnace, the valve of the slag outlet pipeline is opened, and the oxide slag in the furnace is discharged to the outside of the furnace through the slag outlet pipeline 19 under the action of the siphon 18 . According to the calculation, after the Si content in the water 25 containing silicon-based ferroalloys in the furnace is reduced to below 20% and the furnace capacity is accumulated to 40-50% in the furnace, the tap hole pipeline valve 24 is opened, and the tap hole pipeline 23 passes through the tap hole pipeline 23 in the siphon. Under the action of the device 22 , it is discharged to the intermediate pouring treatment equipment 21 for subsequent ferroalloy treatment and utilization, and the molten iron pool that accounts for about 10-20% of the furnace capacity is still maintained in the furnace, which is beneficial to the thermal conductivity of the heating wire device 28 . Among them, for safety consideration, an exhaust pipe 32 controlled by an exhaust pipe valve 31 is designed at the top of the melting furnace to discharge excess gas in the furnace.

The present invention realizes the high efficiency of magnesium metallurgy process through the close connection of logistics and energy flow in the two technological processes of silicon alloy and magnesium metallurgy, especially the technological innovation of MgO reduction method and mechanism, combined with the innovative carbon-free smelting method , low carbon, energy saving and green preparation. The key to the connection of the two metallurgical processes of silicon alloy and magnesium metallurgy is that the MgO reduction process needs to be completed in the silicon alloy from 1410 (the melting point of silicon) to above 1700 °C (the tapping temperature), and at the same time to ensure the refining process of the silicon alloy. minimal impact. Its core is to realize the efficient operation of the magnesium metallurgical process on the basis of maintaining the energy balance, material balance and reaction speed balance in the reaction process. It has been known from the foregoing that silicon-based alloys and MgO participate in the reaction in molten state and solid state, respectively. There are two reactant contact-reaction-separation processes in this process. If the reaction process needs to be completed in a short time, it is necessary to realize a high-speed reaction. That is to say, two phases of the reaction need to be approached at a high speed - a high-speed reaction - a high-speed overflow. This is not possible in a static solution with solid reactants added. Therefore, it is necessary to adopt a core-shell structure in which the liquid phase wraps the solid phase. Because it is necessary to ensure the composition and temperature requirements of the refining of silicon-based alloys, the volume of silicon-based alloys is much larger than that of solid phase, which also ensures the material conditions of the core-shell structure. The sufficient reaction interface of the core-shell structure, the sufficient reaction kinetics formed at high temperature and the shell conditions of rapid overflow can ensure the high rate requirement of magnesium reduction. In addition to the first time, it is also necessary to solve the problem of subsequent processing of the product. The magnesium vapor produced therein will overflow the core-shell structure and be discharged from the reaction system in the gas phase; the solid-phase product SiO ₂ produced therein and impurities such as SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO and other impurities carried along with the addition of MgO, together As the liquid-phase silicon-based iron alloy alloy that has not participated in the reaction needs to re-enter the molten pool, the slag-iron separation process is completed.

The silicon-based alloy of the present invention includes: metal silicon, silicon-based iron alloy, silicon-calcium, silicon-aluminum, silicon-aluminum-iron, silicon-calcium-iron and other alloys with silicon as a component; the present invention can also be used for aluminothermic, silicon thermal, Calcium heat and other metal heat reduction process of solid powder.

Use silicon alloys as both the source of silicon, the reducing agent of magnesium metallurgy, and the heat source of magnesium metallurgy;

The core-shell droplet structure formed by the excessively high-heat liquid-phase silicon-based alloy tightly wraps the MgO particles, which eliminates the gap between the solid-solid reactants, has a high degree of bonding, and has a large contact area. Magnesium metallurgical temperature), and more importantly, the outer diffusion path of magnesium vapor is short, which realizes the rapid approach, rapid reaction and rapid separation between the two phases, and the reduction efficiency is significantly improved;

4. Normal pressure/negative pressure magnesium metallurgy: The Pidgeon method of magnesium smelting adopts the vacuum magnesium smelting process, and the vacuum degree is about 10pa. The purpose is to reduce temperature and improve efficiency. The high temperature reduction conditions given by the present invention do not require vacuum conditions. It can be restored under normal pressure, slight positive pressure and negative pressure:

5. Realize the recovery and utilization of the solidification heat of silicon alloys. Due to the overall backwardness of the domestic ferroalloy forming process, the solidification heat of the ferroalloy has not been recovered. The invention realizes the recovery of the smelting and solidification heat of the silicon-based alloy through the fusion of two metallurgical processes, and significantly reduces the energy consumption of the silicon-based alloy industry.

The present invention can not only be used for the reduction preparation of magnesium metal, but also applicable to the reduction materials that can be used in molten state, if volatile products, such as metals and compounds with low boiling point, can be obtained. Not only the magnesium thermal reaction, the scope of application of this patent can be extended to reduction reactions such as aluminothermic, silicon thermal, calcium thermal and the production of ferro-vanadium, metal manganese, ferro-tungsten, ferro-nickel, and rare earth ferro-silicon and silicon using silicon as a reducing agent. The reaction of calcium-iron, titanium-silicon alloy, silicon-barium, silicon-strontium and other silicon-based composite alloys can make full use of the reaction heat and increase the generation efficiency. It is an epoch-making design that can change the traditional metal smelting method.

Claims (10)

1. A silicon carbide-free thermal reduction magnesium metallurgical device, characterized in that: the upper molten silicon-based ferroalloy furnace, the middle reduction furnace and the lower slag refining furnace, which are communicated in turn, are included; The molten silicon-based ferroalloy furnace (4) is provided with a molten-silicon-based ferroalloy feeding pipe (2) at the upper end, a heating wire device (5) is installed inside, and a molten-silicon-based ferroalloy furnace (35) connected to the middle reduction furnace (35) is provided at the lower end. At the ferroalloy outlet, a pulling rod (3) is installed through the molten silicon-based ferroalloy furnace (4); The atomizing nozzle (41) communicated with the furnace (35), the atomizing nozzle (41) is communicated with the fluidized bed (9) on which the calcined white powder (8) is placed through a pipeline, and the fluidized bed ( 9) There is also a high-pressure argon gas inlet (10) on it; The middle reduction furnace includes an outer shell (38) and a reduction furnace (35) sheathed in the outer shell (38). The upper end of the reduction furnace (35) is communicated with the molten silicon-based iron alloy outlet and the atomizing nozzle (41), and the lower end is communicated with the outlet of the molten silicon-based iron alloy and the atomizing nozzle (41). A gap is left at the lower end of the outer shell (38), the cavity between the outer shell (38) and the reduction furnace (35) forms a magnesium vapor zone (36), a condensation and crystallization device (11) is installed outside the outer shell (38), and the slag at the lower end of the outer shell (38). The outlet (33) is communicated with the lower silicon-based ferroalloy slag refining furnace; The lower silicon-based ferroalloy slag refining furnace is installed on the support material (26), the upper end of the silicon-based ferroalloy slag refining furnace is communicated with the shell slag outlet (33), and the bottom end sidewall is provided with a pouring treatment equipment (21) connected A slag outlet pipe (19) is provided on the upper end side wall, and an exhaust pipe (32) and a rotary blowing device (16) are arranged on the top end, and the rotary blowing device ( 16) The inlet is connected to the argon gas inlet pipe (14), the lower end of the rotary injection device (16) extends into the bottom of the slag refining furnace, and a graphite rotor is installed at the lower end of the rotary injection device (16). 2. The silicon carbide-free thermal reduction magnesium metallurgical device according to claim 1, characterized in that: the molten silicon-based iron alloy furnace (4) is made of insulating material, and the lower end of the molten silicon-based iron alloy furnace (4) is a cone A molten silicon-based ferroalloy feeding pipeline valve (1) is provided on the molten silicon-based ferroalloy feeding pipeline (2). 3. The silicon carbide-free thermal reduction magnesium metallurgical device according to claim 1, characterized in that: a heater (7) is installed on the pipeline connecting the atomizing nozzle (41) with the fluidized bed (9). . 4 . The silicon carbide-free thermal reduction magnesium metallurgical device according to claim 1 , wherein a heating wire device ( 37 ) is installed in the casing ( 38 ), and a high-temperature thermocouple is installed in the reduction furnace ( 35 ). 5 . (13), the upper end of the outer casing (38) and the reduction furnace (35) are both bell-shaped structures, and the lower end of the outer casing (38) is installed with a conical structure formed by a refractory material (34). 5. The metallurgical device for thermal reduction of magnesium without silicon carbide according to claim 1, characterized in that: the inner wall of the casing (38) is provided with hanging fixing devices (12, 39), and the reduction furnace (35) is fixed by hanging The devices (12, 39) are suspended within the housing (38). 6 . The silicon carbide-free thermal reduction magnesium metallurgical device according to claim 1 , wherein a slag outlet valve ( 30 ) is installed on the slag outlet ( 33 ). 7 . 7 . The silicon carbide-free thermal reduction magnesium metallurgical device according to claim 1 , wherein the slag refining furnace is composed of an outer heat insulating material ( 29 ) and an inner refractory material ( 27 ), and the heat insulating material is located in the heat insulating material. 8 . A heating wire device (28) is provided between (29) and the inner refractory material (27). 8 . The silicon carbide-free thermal reduction magnesium metallurgical device according to claim 1 , wherein the exhaust pipe ( 32 ) and the argon gas inlet pipe ( 14 ) are respectively provided with exhaust pipe valves ( 31 ). 9 . and argon inlet line valve (15). 9. The silicon carbide-free thermal reduction magnesium metallurgical device according to claim 1, characterized in that: the tap outlet pipe (23) and the slag outlet pipe (19) are respectively installed with tap pipe valves ( 24) and the slag outlet pipe valve (17), and a tap siphon device (22) and a slag siphon device are respectively installed on the pipes at the rear end of the tap port pipe valve (24) and the slag outlet pipe valve (17). (18). 10. A silicon carbide-free thermal reduction magnesium metallurgical method of the device according to claim 1, characterized in that it comprises the following steps: 1) The high temperature molten silicon-based ferroalloy (6) is controlled by the molten silicon-based ferroalloy feeding pipeline valve (1), and enters the molten silicon-based ferroalloy furnace (4) from the molten silicon-based ferroalloy feeding pipeline (2). (5) Under the joint action of the wrapped insulation material, the reduction reaction conditions of 1500-1800 °C are maintained; 2) Through the up and down operation of the pulling rod (3), the molten silicon-based iron alloy (6) is controlled to enter the intermediate reduction furnace area. (9) is fully mixed with the high-pressure argon gas entering the high-pressure argon gas inlet (10). The molten silicon-based iron alloy (6) enters the reduction furnace (35) together, and interacts with the core-core calcined white powder (8) and the high-speed two-phase flow of the atomizing gas argon. ) to form a certain thickness of silicon-based iron alloy liquid film on the surface to realize the liquid phase, that is, the molten silicon-based iron alloy-coated solid-phase MgO form, that is, to generate a large number of spray-like liquid-phase silicon-based alloy-coated solid-phase powder droplets (40), which enter Go to the middle high temperature reduction zone for magnesium metal reduction metallurgy; 3) The liquid-phase silicon-based alloy encapsulated solid-phase powder droplets react at a temperature of 1450-1700 °C, wherein the heating wire device (37) regulates the reduction reaction temperature, and the reaction formula is: 2MgO(s)+Si(Fe)(l)=2Mg(g)+SiO2(s) SiO2(s)+2CaO(s)=2CaO·SiO2(l) The high-temperature magnesium vapor generated by the reaction moves downward under the action of the upper end pressure. Due to the low density and high temperature, after leaving the reduction furnace (35) from the lower part, it turns upward from the magnesium vapor zone (36) and enters the condensing and crystallization device (11). ) when it is condensed into crystalline magnesium; 4) The SiO2 generated during the reaction and the CaO·SiO2 generated by the subsequent reaction are wrapped in the silicon-based alloy liquid. Under the action of gravity, together with iron and other solid impurities that did not participate in the reaction, they pass through the slag outlet valve (30) from the slag outlet. (33) falling into the slag refining furnace; 5) The lower refining furnace is protected by the internal refractory material (27), and the outer layer is provided with a heating wire device (28) to ensure that the refining furnace temperature is 1400-1500 ℃, the ferroalloy is located in the lower part of the refining furnace, and the oxide slag is located in the upper part of the refining furnace , using the graphite rotor at the end of the rotary blowing device (16) at the bottom of the refining furnace molten pool, and under the control of the argon inlet pipe valve (15), argon is blown into the argon inlet pipe (14), and the resulting fine argon The bubbles play a role in stirring the melt during the floating process, driving the light oxide impurities to float up and promoting the separation of impurities, that is, the slag melt is purified and the various components in it are mixed evenly; 6) After the slag (20) in the refining furnace has accumulated to the depth set by the refining furnace, open the valve of the slag outlet pipeline, and the oxide slag in the refining furnace will pass through the slag outlet pipeline ( 19) Discharge to the outside of the furnace. After the refining furnace contains silicon-based ferroalloy water (25) accumulatively 40-50% of the refining furnace capacity, open the tap pipe valve (24), and pass the tap pipe (23) in the siphon. Under the action of the device (22), it is discharged to the intermediate pouring treatment equipment (21) for subsequent ferroalloy treatment and utilization, and the molten iron pool with 10-20% of the furnace capacity is still maintained in the refining furnace. The exhaust pipe (32) controlled by the gas pipe valve (31) is used to control the pressure in the furnace.

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