Process and apparatus for magnesium production by a slag-free carbothermic process with quench condenser

Abstract

This invention relates to a slag-free carbothermic magnesium smelting method and apparatus with a quenching condenser. The method includes: furnace gas generated by a magnesium smelting electric arc furnace entering a reheating chamber; the reheating chamber maintaining the temperature of the furnace gas; the quenching condenser quenching and condensing magnesium vapor in the furnace gas, causing the cooled and sublimated magnesium crystal particles to be enveloped by liquid hydrocarbons and enter a first cooling chamber; the first cooling chamber cooling the gasified hydrocarbons in the mixed furnace gas back into liquid hydrocarbons, with the liquid hydrocarbons carrying solid magnesium crystal particles continuously cooling and condensing; a second cooling chamber cooling the remaining furnace gas, causing any uncondensed gasified liquid hydrocarbons to further condense and drip to collect at the bottom of the second cooling chamber, and allowing carbon monoxide in the furnace gas to be discharged through dust removal and used downstream; a solid-liquid centrifugal separator is installed below the first cooling chamber to separate the solid-liquid two-phase mixture collected at the bottom of the first cooling chamber. This invention has advantages such as environmental friendliness and safety.

Description

Technical Field

[0001] This invention relates to the field of magnesium smelting technology, specifically to a slag-free carbothermic magnesium smelting method and apparatus with a quenching condenser. Background Technology

[0002] There are three technological approaches to magnesium smelting. Extracting metallic magnesium from seawater, brine, and magnesite commonly involves electrolysis, which produces magnesium but also chlorine as a byproduct. Onshore magnesium smelting uses dolomite and the Pidgeon process, employing ferrosilicon as a reducing agent, but this generates up to six times the amount of solid waste. Alternatively, a slag-free carbothermic process can be used for seawater, brine, and magnesite, where the Mg vapor obtained from the high-temperature reduction reaction reacts with carbon monoxide gas in the furnace gas during the cooling process.

[0003] However, current electrolytic chlorine production methods generate significant pollution, corroding equipment, poisoning workers, and polluting the environment, making remediation difficult and resulting in HSE (Health, Safety, and Environment) indicators failing to meet contemporary societal requirements. The Pidgeon process for magnesium smelting from dolomite produces fine dust waste exceeding six times the weight of the main product, causing severe environmental impact. Slag-free carbothermic reduction magnesium smelting inevitably involves reverse reactions in high-temperature furnace gases, leading to very low product yields and high production costs. Furthermore, the resulting crystalline magnesium is a solid powder, which is highly flammable and explosive.

[0004] Therefore, there is an urgent need for a more environmentally friendly and safer slag-free carbothermic magnesium smelting method and apparatus with a quenching condenser. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the prior art by providing a slag-free carbothermic magnesium smelting method and apparatus with a quenching condenser.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A slag-free carbothermic magnesium smelting apparatus with a quenching condenser includes a magnesium smelting electric arc furnace, a reheating chamber, a quenching condenser, a first cooling chamber, and a second cooling chamber arranged sequentially.

[0007] The magnesium smelting electric arc furnace is a heating furnace that uses electric arc heating to isolate air, and is connected to the reheating chamber through a gas channel so that the furnace gas generated by the reaction can enter the reheating chamber.

[0008] The heating chamber is used to maintain the temperature of the furnace gas and is connected to the inlet of the quenching condenser.

[0009] The quenching condenser receives partially vaporized liquid hydrocarbons injected at high speed from the coolant vaporization and heat preservation tank. The hydrocarbons enter the ejector mixing chamber inside the quenching condenser, where furnace gas is drawn in and mixed while undergoing isentropic expansion to rapidly cool the mixed gas. This causes the magnesium vapor in the furnace gas to undergo quenching and condensation, and the cooled and sublimated magnesium crystal particles are encapsulated by the liquid hydrocarbons and enter the first cooling chamber.

[0010] The first cooling chamber is used to cool down the gasified hydrocarbons in the mixed furnace gas and turn them back into liquid hydrocarbons. The liquid hydrocarbons carrying solid magnesium crystal particles are continuously cooled and condensed, causing them to collect at the bottom of the first cooling chamber. A cold drain valve is provided at the bottom of the first cooling chamber to periodically drain the condensed liquid hydrocarbons carrying magnesium crystal particles.

[0011] The second cooling chamber is used to cool the remaining furnace gas, so that the uncondensed gasified liquid hydrocarbons in it are further condensed and dripped to collect at the bottom of the second cooling chamber, and the carbon monoxide in the furnace gas is discharged through dust removal and enters the downstream for use.

[0012] A solid-liquid centrifugal separator is installed below the first cooling chamber. The solid-liquid centrifugal separator is used to separate the solid-liquid two-phase mixture that has gathered at the bottom of the first cooling chamber. The solid-liquid two-phase mixture consists of liquid hydrocarbons containing magnesium crystal particles after condensation and solid magnesium particles after condensation. The separation products are liquid hydrocarbons without solid impurities and oily magnesium particles.

[0013] Working principle and beneficial effects: 1. Compared with existing technologies, this application uses a quenching condenser to rapidly cool the furnace gas, ensuring that the mixed furnace gas cools completely before any reverse reaction occurs, or with only a very small degree of reverse reaction. This causes metallic magnesium to condense into a crystalline solid, thus separating it from the accompanying carbon monoxide furnace gas. Simultaneously, the condensed metallic magnesium crystalline particles are encapsulated in liquid hydrocarbons, protecting them from contact with air and eliminating safety risks. This prevents their large surface area from igniting or exploding upon contact with air. Subsequently, centrifugal separation using a solid-liquid centrifuge, followed by vacuum distillation, further effectively separates the magnesium to obtain a high-purity metallic product, realizing the purification of metallic magnesium into a commercial product. This completely solves the problems of easy ignition and explosion, and high production cost in existing technologies.

[0014] 2. Compared with existing technologies, this application utilizes a quenching condenser, which allows for rapid condensation and collection of magnesium vapor, resulting in a high recovery rate. Simultaneously, the overall process generates almost no waste residue, with most of it being recyclable or reprocessed to obtain industrial finished products.

[0015] Furthermore, some of the vaporized liquid hydrocarbons in the coolant vaporization insulation tank enter the quenching condenser through the ejector main flow channel and are ejected from the lobed nozzle of the ejector main flow channel, thus entering the ejector mixing chamber.

[0016] Furthermore, a turbulence cone, a converging tube, a throat, an expansion tube, and a parallel tube are sequentially arranged in the direction of the lobed nozzle ejection to enhance the momentum mixing of the partially vaporized liquid hydrocarbons with the furnace gas and perform isentropic expansion to do work, so that the liquid hydrocarbons are accelerated to multiple times the supersonic speed and rapidly cooled after mixing with the furnace gas.

[0017] Furthermore, it also includes a magnesium distillation furnace for distilling the centrifuge residue solids obtained from the solid-liquid centrifuge. The magnesium distillation furnace is also connected in sequence to a primary cooling chamber and a secondary cooling chamber for cooling the furnace gas generated during distillation. Pure crystalline magnesium is obtained by condensation in the primary cooling chamber and liquid hydrocarbons are obtained by cooling in the secondary cooling chamber.

[0018] Furthermore, it also includes a separation coolant storage tank for storing the liquid separated by the solid-liquid centrifugal separator. The separation coolant storage tank is also connected in sequence to a liquid pressurizing pump and a heat exchange vaporizer. After being pressurized by the liquid pressurizing pump, the liquid enters the heat exchange vaporizer for vaporization and is then stored in a coolant vaporization insulation tank to achieve recycling.

[0019] Furthermore, a parallel pipe is introduced from one side of the first cooling chamber along the tangent of the inner wall of the first cooling chamber, so that the furnace gas and liquid hydrocarbons entering the first cooling chamber can form a swirling airflow in the first cooling chamber.

[0020] Furthermore, the top of the first cooling chamber is equipped with multiple upper evaporator heat exchangers, and the bottom is equipped with multiple outer shell evaporator tubes.

[0021] Furthermore, the solid-liquid centrifuge includes an annular receiving tank, a centrifuge base located within the annular receiving tank, and a centrifugal settling zone and a centrifugal filtration zone located on top of the centrifuge base. The centrifuge base is driven to rotate by a motor, thereby causing the centrifugal settling zone and the centrifugal filtration zone to rotate at high speed. The top of the annular receiving tank has an opening to receive the liquid material ejected from the centrifugal filtration zone through the pores, and the bottom has a discharge outlet for liquid discharge and storage. The upper part of the centrifugal settling zone is the centrifugal filtration zone, which is equipped with a solid-liquid microporous filter plate so that the separated liquid ejected by centrifugation can enter the annular receiving tank and flow downwards along the channel inside the annular receiving tank for discharge.

[0022] Furthermore, the second cooling chamber is also connected in sequence to a dust collector, an explosion-proof induced draft fan, and a by-product gas storage tank. The dust collector removes carbon monoxide, and the by-product gas is stored in the storage tank by the explosion-proof induced draft fan.

[0023] A slag-free carbothermic magnesium smelting method with a quenching condenser, using the aforementioned slag-free carbothermic magnesium smelting apparatus with a quenching condenser, includes the following steps:

[0024] Solid materials containing magnesium oxide and carbon reducing agent are added to the hollow top electrode of the magnesium smelting electric arc furnace and transported into the magnesium smelting electric arc furnace through low-pressure methane gas. The high-temperature electric arc radiation of the magnesium smelting electric arc furnace heats the solid materials to produce a carbothermic reduction reaction, generating a high-temperature furnace gas composed of magnesium vapor and CO gas.

[0025] High-temperature furnace gas enters the heat compensation chamber through the gas channel, and the heat compensation chamber compensates for the temperature to maintain it at the set temperature.

[0026] High-temperature furnace gas enters the quenching and condensing unit through the heating chamber. Partially vaporized liquid hydrocarbons are injected into the quenching and condensing unit as the main gas through the coolant vaporization and insulation tank. They are then mixed with the high-temperature furnace gas through the corrugated nozzle to enhance momentum mixing. While mixing, the gas and liquid mixtures enter the quenching and condensing unit through the injection mixing chamber and Laval nozzle. The mixture undergoes isentropic expansion and does work, while being accelerated to several times the speed of sound. This causes the magnesium vapor in the furnace gas to be quenched and condensed, and the cooled and sublimated magnesium crystal particles are encapsulated by the liquid hydrocarbons and enter the first cooling chamber.

[0027] The furnace gas and liquid hydrocarbons carrying magnesium crystal particles enter the first cooling chamber for cooling, which causes the vaporized liquid hydrocarbons in the furnace gas to cool, condense and drip down, and the vaporized liquid hydrocarbons are cooled and re-condensed into liquid, causing the liquid hydrocarbons carrying magnesium crystal particles to condense and collect at the bottom of the first cooling chamber.

[0028] The remaining furnace gas and the remaining unliquefied liquid hydrocarbons enter the second cooling chamber for cooling and condensation, and collect at the bottom of the second cooling chamber. The carbon monoxide in the chamber is removed by dust removal and stored.

[0029] The solid-liquid two-phase mixture inside the first cooling chamber is periodically discharged, and the liquid hydrocarbons and solids are separated by a solid-liquid centrifuge.

[0030] Liquid hydrocarbons are repressurized and vaporized for storage in a coolant vaporization and insulation tank;

[0031] The oily solid separated by centrifugation was distilled, and the gas produced by distillation was cooled in two stages at different temperatures to obtain pure crystalline magnesium and liquid hydrocarbons, respectively. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of an electric arc furnace for magnesium smelting;

[0034] Figure 3 This is a schematic diagram of the structure of a quenching condenser;

[0035] Figure 4 yes Figure 3 Cross-sectional view of AA in the middle;

[0036] Figure 5 This is a diagram showing the positional relationship between the parallel pipe and the first cooling chamber;

[0037] Figure 6 This is a schematic diagram of the structure of the first and second cooling chambers;

[0038] Figure 7 This is a structural diagram of a solid-liquid centrifuge;

[0039] Figure 8 This is a structural diagram of a magnesium distillation furnace.

[0040] In the diagram, 101 is the magnesia smelting electric arc furnace; 102 is the furnace shell; 103 is the insulation layer; 104 is the graphite furnace lining; 105 is the hollow top electrode; 106 is the bottom electrode; 107 is the gas passage; 108 is the slag removal tank; 109 is the raw material tank; 110 is the hydrocarbon gas storage tank; 120 is the reheating chamber; 121 is the reheating electrode anode; 122 is the reheating electrode cathode; 123 is the high-temperature furnace gas induced passage; 201 is the quenching condenser; 202 is the ejector main gas flow channel; and 204 is the coolant vaporization insulation tank. 205. Waveform nozzle; 206. Ejector mixing chamber; 207. Turbulence cone; 208. Converging tube; 209. Throat; 210. Expansion tube; 211. Parallel tube; 301. First cooling chamber; 302. First cooling chamber drain valve; 303. First cooling chamber outer shell evaporator tube; 304. First cooling chamber upper evaporator heat exchanger; 305. Second cooling chamber upper water-cooled tube; 306. Second cooling chamber constant temperature water bath; 307. Second cooling chamber cooling water inlet; 308. Second cooling chamber cooling water outlet; 309. Solid-liquid two-phase mixture; 31 0. Secondary cooling chamber; 311. Secondary cooling drain valve; 320. Dust collector; 321. Explosion-proof induced draft fan; 322. By-product gas storage tank; 501. Solid-liquid centrifuge; 502. Separated coolant storage tank; 503. Liquid pressurization pump; 504. Heat exchange vaporizer; 505. Annular receiving tank; 506. Centrifuge base; 507. Solid residue; 508. Solid-liquid two-phase mixture; 509. Separated liquid; 510. Secondary cooling liquid storage tank; 515. Centrifugal settling zone; 516. Solid-liquid micro-... 601. Perforated filter plate; 602. Magnesium distillation furnace; 603. Heating chamber; 604. Distillation primary cooling chamber; 605. Distillation secondary cooling chamber; 606. Vacuum pump; 607. Primary cooling constant temperature cooling tank; 608. Secondary cooling constant temperature liquid tank; 609. Crystalline magnesium; 620. Condensed hydrocarbon; 621. Heat source inlet; 622. Waste heat source outlet; 623. Crystalline magnesium primary cooling coolant inlet; 624. Crystalline magnesium secondary cooling water inlet; 625. Crystalline magnesium secondary cooling water outlet. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0042] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0043] Seawater and salt lake brines contain magnesium ions. Magnesium hydroxide precipitate is obtained by adding lime, ammonia, or NaOH alkaline solution. Calcination of this precipitate yields MgO, the raw material for carbothermic magnesium smelting. Current technologies primarily involve reacting MgO with carbon under high-temperature electrothermal conditions to undergo the following reduction reaction. For example, using an electric arc furnace 101 for magnesium smelting, at approximately 2000℃, the product magnesium vapor and byproduct CO gas form a mixed furnace gas that escapes into the condenser. As the temperature decreases, the reverse reaction occurs again, and the Mg vapor is re-oxidized by CO back to MgO, resulting in a lower desired yield of metallic magnesium. The reaction formula is as follows:

[0044]

[0045] Therefore, it is necessary to improve the existing slag-free carbothermic process for magnesium smelting, thereby increasing the yield of metallic magnesium and improving safety performance.

[0046] Example 1

[0047] like Figure 1 As shown, this slag-free carbothermic magnesium smelting apparatus with a quenching condenser includes a magnesium smelting electric arc furnace 101, a reheating chamber 120, a quenching condenser 201, a first cooling chamber 301, and a second cooling chamber 310 arranged in sequence.

[0048] Among them, the magnesium smelting electric arc furnace 101 is a heating furnace that is heated by electric arc and isolated from air, and is connected to the heat exchange chamber 120 through the gas channel 107 so that the furnace gas generated by the reaction enters the heat exchange chamber 120.

[0049] In this embodiment, as Figure 2 As shown, the magnesia smelting electric arc furnace 101 includes an electric furnace steel shell 102. The electric furnace steel shell 102 has a slag cleaning trough 108 inclined downward on one side and a gas channel 107 inclined upward on the other side. A hollow top electrode 105 is provided at the top and a bottom electrode 106 is provided at the bottom. The top electrode is the cathode and the bottom electrode 106 is the anode. Both are made of ultra-high power graphite electrodes. The inner wall is provided with a graphite furnace lining 104 and an insulation layer 103.

[0050] During processing, solid materials (MgO particles or powder, also containing coke particles or powder and bio-pyrolysis carbon particles or powder, originating from raw material tank 109) and methane (CH4) gas (from hydrocarbon storage tank 110) are added from the hollow top electrode 105. Under the high temperature of the electric arc and at atmospheric pressure, exceeding 2000℃, a carbothermic reduction reaction for magnesium smelting occurs.

[0051]

[0052] The furnace gas consists of Mg vapor and by-product CO gas, with a temperature exceeding 2000 degrees Celsius. Due to the addition of methane, it also contains a certain proportion of H2.

[0053] In this embodiment, the carbon from bio-pyrolysis originates from the following:

[0054] Methane gas undergoes thermal decomposition under the action of a high-temperature electric arc:

[0055] There are three sources of carbon in the furnace: coke, carbon from bio-pyrolysis, and carbon black particles from methane pyrolysis.

[0056] The heating chamber 120 is used to maintain the temperature of the furnace gas and is connected to the inlet of the quenching condenser 201 through the high-temperature furnace gas intake channel 123.

[0057] In this embodiment, as Figure 3 As shown, the gas enters the heating chamber 120 through the insulated gas channel 107. Inside the heating chamber 120, there is a set of low-power electrodes (heating electrode anode 121 and heating electrode cathode 122) for electric arc heating to raise or maintain the high temperature of the mixed furnace gas.

[0058] Among them, such as Figure 3 As shown, the quenching condenser 201 receives partially vaporized liquid hydrocarbons injected at high speed from the coolant vaporization and heat preservation tank 204, which enter the ejector mixing chamber 206 inside the quenching condenser 201. The furnace gas is drawn in and mixed while undergoing isentropic expansion to rapidly cool the mixed gas, causing the magnesium vapor in the furnace gas to undergo quenching and condensation. The cooled and sublimated magnesium crystal particles are then enveloped by the liquid hydrocarbons and enter the first cooling chamber 301.

[0059] In this embodiment, a coolant composed of liquid hydrocarbons, i.e., diesel oil, at room temperature, is pressurized to a high pressure of 1.5-5 MPa. After passing through a heat exchanger, it vaporizes into a high-temperature hydrocarbon gas at 150-200°C, carrying a certain proportion of unevaporated liquid diesel oil. Thus, with a circulation rate 40-50 times the mass of magnesium metal produced per hour, the coolant vaporization and heat preservation tank 204 enters the quenching and condensing unit 201 through the main ejector channel 202, and exits at high speed through the wave-shaped nozzle 205 (e.g., ...). Figure 4As shown, the gas is ejected and enters the ejector mixing chamber 206. The high-temperature furnace gas is ejected into the ejector mixing chamber 206. With the assistance of the turbulence cone 207, the mixing and ejection effect is further enhanced, and efficient momentum transfer and mixing are carried out. The high-temperature furnace gas passes through the converging tube 208-throat 209-expansion tube 210-parallel tube 211 and undergoes isentropic expansion, realizing the conversion of gas internal energy into kinetic energy, reaching several times the speed of sound, i.e., Ma>>1. At the same time, the overall temperature of the mixed furnace gas drops at a rate of 10^6 K / s, which is generally in the milliseconds when passing through a quencher several meters long. At the same time, the overall temperature drops to below 300℃, and the magnesium vapor undergoes quenching and condensation. The magnesium crystal particles are wrapped by liquid hydrocarbons (liquid hydrocarbon diesel).

[0060] The first cooling chamber 301 is used to cool down the gasified hydrocarbons in the mixed furnace gas and turn them back into liquid hydrocarbons. The liquid hydrocarbons carrying solid magnesium crystal particles are continuously cooled and condensed, causing them to collect at the bottom of the first cooling chamber 301. A cold drain valve 302 is provided at the bottom of the first cooling chamber 301 to periodically drain the condensed liquid hydrocarbons carrying magnesium crystal particles.

[0061] Preferably, such as Figure 5 As shown, the parallel pipe 211 enters from one side of the first cooling chamber 301 along the tangent of the inner wall of the first cooling chamber 301, so that the furnace gas and liquid hydrocarbons entering the first cooling chamber 301 can form a swirling airflow within the first cooling chamber 301, thereby achieving better cooling.

[0062] In this embodiment, the top of the first cooling chamber 301 is provided with a plurality of upper evaporator heat exchangers 304 and the bottom is provided with a plurality of outer shell evaporator tubes 303.

[0063] In this embodiment, as Figure 6 As shown, liquid hydrocarbons (liquid diesel fuel) containing magnesium crystal particles enter the first cooling chamber 301. The volatile portion is cooled by a cold upper evaporator heat exchanger 304 at the top of the first cooling chamber 301 and re-condenses and drips down. The liquid portion flows downward and is condensed by multiple cold outer shell evaporator tubes 303 located on the bottom outer shell of the first cooling chamber 301, collecting at the bottom of the first cooling chamber 301 and can be periodically discharged through a cold drain valve 302.

[0064] The second cooling chamber 310 is used to cool the remaining furnace gas, so that the uncondensed gasified liquid hydrocarbons in it are further condensed and dripped to collect at the bottom of the second cooling chamber 310, and the carbon monoxide in the furnace gas is discharged through dust removal and enters the downstream for use.

[0065] In this embodiment, the second cooling chamber 310 is also sequentially connected to a dust collector 320, an explosion-proof induced draft fan 321, and a by-product gas storage tank 322. The dust collector 320 removes carbon monoxide, which is then stored in the by-product gas storage tank 322 via the explosion-proof induced draft fan 321. Some gaseous hydrocarbons continue into the second cooling chamber 310, are cooled by the upper water-cooling pipe 305, and collect at the lower part of the second cooling chamber 310, where they can be stored in the secondary cooling liquid storage tank 510. The remaining CO and some H2 gases pass through a dust collector and an exhaust fan before entering the by-product gas storage tank 322, where they can be used to prepare other products using existing technologies.

[0066] The second cooling chamber 310 is equipped with a secondary cooling constant temperature water tank 306, which has a secondary cooling water inlet 307 and a secondary cooling water outlet 308.

[0067] The first cooling chamber 301 is equipped with a solid-liquid centrifugal separator 501. The solid-liquid centrifugal separator 501 is used to separate the solid-liquid two-phase mixture 508 / 309 that is collected at the bottom of the first cooling chamber 301. The solid-liquid two-phase mixture 508 / 309 consists of liquid hydrocarbons containing magnesium crystal particles after condensation and solid magnesium particles after condensation. The separation products are liquid hydrocarbons without solid impurities and oily magnesium particles.

[0068] In this embodiment, as Figure 7 As shown, the solid-liquid centrifuge 501 includes an annular receiving tank 505, a centrifuge base 506 disposed within the annular receiving tank 505, and a centrifugal settling zone 515 and a centrifugal filtration zone disposed on the top of the centrifuge base 506. The centrifuge base 506 is driven to rotate by a motor, thereby driving the centrifugal settling zone 515 and the centrifugal filtration zone to rotate at high speed. The top of the annular receiving tank 505 has an opening to receive the liquid material thrown out of the centrifugal filtration zone through the pores, and the bottom has a discharge outlet for liquid discharge and storage. The upper part of the centrifugal settling zone 515 is the centrifugal filtration zone, which is provided with a solid-liquid microporous filter plate 516 so that the separated liquid 509 thrown out by centrifugation can enter the annular receiving tank 505 and flow downward along the channel inside the annular receiving tank 505 for discharge.

[0069] In this embodiment, as Figure 8 As shown, it also includes a magnesium distillation furnace 601, which is used to distill the centrifuge residue (solid residue 508) obtained by the solid-liquid centrifuge 501. The magnesium distillation furnace 601 is also connected in sequence to a primary cooling chamber 603 and a second cooling chamber 604, which are used to cool the furnace gas generated during distillation. Pure crystalline magnesium 608 is obtained by condensation in the primary cooling chamber 603 and liquid hydrocarbons are obtained by cooling in the second cooling chamber 604.

[0070] The magnesium distillation furnace 601 is equipped with a heating chamber 602, which has a heat source inlet 620 and a waste heat source outlet 621.

[0071] The distillation primary cooling chamber 603 is equipped with a primary cooling constant temperature cooling tank 606, which has a magnesium primary cooling coolant inlet 622 and a magnesium primary cooling coolant outlet 623. The distillation secondary cooling chamber 604 is equipped with a secondary cooling constant temperature liquid tank 607, which has a magnesium secondary cooling water inlet 624 and a magnesium secondary cooling water outlet 625. The distillation secondary cooling chamber 604 is evacuated by a vacuum pump 605.

[0072] In this embodiment, the solid residue 508 is mainly the solid residue on the inner wall of the centrifuge drum, primarily composed of Mg crystal particles, with a certain amount of MgO, carbon black particles, and diesel paste. During distillation, the primary cooling chamber 603 is maintained at 400°C, and the magnesium evaporates and condenses to obtain pure crystalline magnesium 608. The furnace gas continues to enter the secondary cooling chamber 604, where the temperature is controlled at 50°C, and the adhering diesel is cooled and reused.

[0073] In this embodiment, as Figure 1 As shown, it also includes a separation coolant storage tank 502 for storing the liquid separated by the solid-liquid centrifugal separator 501. The separation coolant storage tank 502 is also connected in sequence to a liquid pressurizing pump 503 and a heat exchange vaporizer 504. After being pressurized by the liquid pressurizing pump 503, the liquid enters the heat exchange vaporizer 504, is vaporized, and then stored in the coolant vaporization insulation tank 204 to achieve recycling.

[0074] Example 2

[0075] A slag-free carbothermic magnesium smelting method with a quenching condenser 201, using the slag-free carbothermic magnesium smelting apparatus of Example 1 with a quenching condenser 201, includes the following steps:

[0076] Step 1: Add solid material containing magnesium oxide and carbon reducing agent to the hollow top electrode 105 of the magnesium smelting electric arc furnace 101, and transport it into the magnesium smelting electric arc furnace 101 through low-pressure methane gas. The solid material is heated by the high-temperature electric arc radiation of the magnesium smelting electric arc furnace 101 to produce a carbothermic reduction reaction, which generates furnace gas composed of magnesium vapor and carbon monoxide gas.

[0077] Step 2: The high-temperature furnace gas enters the heat compensation chamber 120 through the gas channel 107, and the temperature is compensated by the heat compensation chamber 120 to maintain it at the set temperature.

[0078] Step 3: The high-temperature furnace gas enters the quenching and condensing condenser 201 through the heating chamber 120. Partially vaporized liquid hydrocarbons are injected into the quenching and condensing condenser 201 as the main gas through the coolant vaporization and heat preservation tank 204. They are then mixed with the high-temperature furnace gas through the wave-shaped nozzle 205 to enhance momentum mixing. While mixing, the gas and liquid mixture enter the injection mixing chamber 206 in the quenching and condensing condenser 201. The mixed gas and liquid undergo isentropic expansion and work through the Laval nozzle, and are accelerated to multiple times the speed of sound. This causes the magnesium vapor in the furnace gas to be quenched and condensed, and the cooled and sublimated magnesium crystal particles are encapsulated by the liquid hydrocarbons and enter the first cooling chamber 301.

[0079] Step 4: The furnace gas and liquid hydrocarbons carrying magnesium crystal particles enter the first cooling chamber 301 for cooling, so that the vaporized liquid hydrocarbons in the furnace gas are cooled, condensed and dripped down, and the vaporized liquid hydrocarbons are cooled and re-condensed into liquid, so that the liquid hydrocarbons carrying magnesium crystal particles condense and collect at the bottom of the first cooling chamber 301.

[0080] Step 5: The remaining furnace gas and the remaining unliquefied liquid hydrocarbons enter the second cooling chamber 310 for cooling and condensation, and collect at the bottom of the second cooling chamber 310. The carbon monoxide in the chamber is removed by dust removal and stored.

[0081] Step 6: Periodically discharge the solid-liquid two-phase mixture 508 / 309 inside the first cooling chamber 301, and separate the liquid hydrocarbons and solids 509 by a solid-liquid centrifuge 501;

[0082] Step 7: Repressurize and vaporize the liquid hydrocarbons and store them in the coolant vaporization and insulation tank 204;

[0083] Step 8: The oily solid separated by centrifugation is distilled, and the gas produced by distillation is cooled in two stages at different temperatures to obtain pure crystalline magnesium 608 and condensed hydrocarbons, respectively.

[0084] The parts of this invention not described in detail are prior art, therefore they are not described in detail here.

[0085] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0086] Although this paper extensively uses components such as the magnesium smelting electric arc furnace 101, electric furnace steel shell 102, insulation layer 103, graphite furnace lining 104, hollow top electrode 105, bottom electrode 106, gas channel 107, slag cleaning tank 108, raw material tank 109, gas hydrocarbon storage tank 110, reheating chamber 120, reheating electrode anode 121, reheating electrode cathode 122, high-temperature furnace gas induced channel 123, quenching condenser 201, ejector main gas flow channel 202, coolant vaporization insulation tank 204, and wave... 205. Flange-shaped nozzle, 206. Injector mixing chamber, 207. Turbulence cone, 208. Tapered tube, 209. Throat, 210. Expansion tube, 211. First cooling chamber, 301. First cooling drain valve, 302. First cooling shell evaporator, 303. First cooling upper evaporator heat exchanger, 304. Second cooling upper water cooling pipe, 305. Second cooling constant temperature water bath, 306. Second cooling water inlet, 307. Second cooling water outlet, 308. Solid-liquid two-phase mixture, 508 / 309. Second cooling chamber, 310. 311 Secondary cooling drain valve, 320 Dust collector, 321 Explosion-proof induced draft fan, 322 By-product gas storage tank, 501 Solid-liquid centrifuge, 502 Separation coolant storage tank, 503 Liquid pressurization pump, 504 Heat exchange vaporizer, 505 Annular receiving tank, 506 Centrifuge base, 507 Solid residue, 508 / 309 Solid-liquid two-phase mixture, 509 Separated liquid, 510 Secondary cooling storage tank, 515 Centrifugal settling zone, 516 Solid-liquid microporous filter plate, 60 Magnesium distillation furnace 1. The terms used include heating chamber 602, distillation primary cooling chamber 603, distillation secondary cooling chamber 604, vacuum pump 605, primary cooling constant temperature cooling tank 606, secondary cooling constant temperature liquid tank 607, crystalline magnesium 608, condensate hydrocarbon 609, heat source inlet 620, waste heat source outlet 621, crystalline magnesium primary cooling coolant inlet 622, crystalline magnesium primary cooling coolant outlet 623, crystalline magnesium secondary cooling water inlet 624, and crystalline magnesium secondary cooling water outlet 625, etc., but the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

[0087] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes made to their shape or structure, any technical solution that is the same as or similar to that of this application falls within the protection scope of this invention.

Claims

1. A slag-free carbothermic magnesium smelting apparatus with a quenching condenser, characterized in that, It includes a magnesium smelting electric arc furnace, a reheating chamber, a quenching condenser, a first cooling chamber, and a second cooling chamber arranged in sequence. The magnesium smelting electric arc furnace is an electric arc heating furnace that isolates air, and is connected to the heat exchange chamber through a gas channel so that the furnace gas generated by the reaction enters the heat exchange chamber. The heating chamber is used to maintain the furnace gas at a high temperature before it enters the quenching and condensing unit to suppress the occurrence of the reverse reaction, and is connected to the inlet of the quenching and condensing unit. The quenching and condensing unit receives partially vaporized liquid hydrocarbons injected at high speed from the coolant vaporization and insulation tank. These hydrocarbons enter the ejector mixing chamber within the quenching and condensing unit, where the furnace gas is drawn in and undergoes isentropic expansion while being mixed, causing the mixed gas to accelerate to multiple times the speed of sound and cool rapidly. This causes the magnesium vapor in the furnace gas to undergo quenching and condensation, and the cooled and sublimated magnesium crystal particles are encapsulated by the liquid hydrocarbons and enter the first cooling chamber. The first cooling chamber is used to cool down the gasified hydrocarbons in the mixed gas and turn them back into liquid hydrocarbons. The liquid hydrocarbons carrying solid magnesium crystal particles are continuously cooled and condensed, causing them to collect at the bottom of the first cooling chamber. The bottom of the first cooling chamber is equipped with a cold drain valve for periodically draining the condensed liquid hydrocarbons carrying magnesium crystal particles. The second cooling chamber is used to cool the remaining furnace gas entering, so that the gasified hydrocarbons that have not yet condensed will be further condensed and dripped to collect at the bottom of the second cooling chamber, and the carbon monoxide in the furnace gas will be discharged through dust removal and enter downstream for use; A solid-liquid centrifugal separator is provided below the first cooling chamber. The solid-liquid centrifugal separator is used to separate the solid-liquid two-phase mixture collected at the bottom of the first cooling chamber. The solid-liquid two-phase mixture consists of liquid hydrocarbons containing magnesium crystal particles after condensation and solid magnesium particles after condensation. The separation products are liquid hydrocarbons without solid impurities and oily magnesium particles. In this process, a portion of the vaporized liquid hydrocarbons in the coolant vaporization and insulation tank enters the quenching and condensing unit through the main ejector flow channel and is ejected from the corrugated nozzle of the main ejector flow channel, thereby entering the ejector mixing chamber. A turbulence cone, a converging tube, a throat, an expansion tube, and a parallel tube are arranged sequentially in the ejection direction of the corrugated nozzle, so that a portion of the vaporized liquid hydrocarbons draws the furnace gas to enhance momentum mixing and perform isentropic expansion to do work, so that the liquid hydrocarbons and furnace gas are accelerated to multiple times supersonic speed and rapidly cooled after mixing.

2. The slag-free carbothermic magnesium smelting apparatus with a quenching condenser according to claim 1, characterized in that, It also includes a magnesium distillation furnace for distilling the centrifuge residue solids obtained from the solid-liquid centrifuge. The magnesium distillation furnace is also connected in sequence to a primary cooling chamber and a secondary cooling chamber for cooling the furnace gas generated during distillation. Pure crystalline magnesium is obtained by condensation in the primary cooling chamber and the liquid hydrocarbons are obtained by cooling in the secondary cooling chamber.

3. The slag-free carbothermic magnesium smelting apparatus with a quenching condenser according to claim 1, characterized in that, It also includes a separation coolant storage tank for storing the liquid separated by the solid-liquid centrifugal separator. The separation coolant storage tank is also connected in sequence to a liquid pressurizing pump and a heat exchange vaporizer. After being pressurized by the liquid pressurizing pump, the liquid enters the heat exchange vaporizer, is vaporized, and then stored in the coolant vaporization insulation tank to achieve recycling.

4. The slag-free carbothermic magnesium smelting apparatus with a quenching condenser according to claim 2, characterized in that, The parallel pipe enters from one side of the first cooling chamber along the tangent of the inner wall of the first cooling chamber, so that the furnace gas and liquid hydrocarbons entering the first cooling chamber can form a swirling airflow in the first cooling chamber.

5. The slag-free carbothermic magnesium smelting apparatus with a quenching condenser according to claim 1, characterized in that, The first cooling chamber has multiple upper evaporator heat exchangers inside the top and multiple outer shell evaporator tubes outside the bottom.

6. The slag-free carbothermic magnesium smelting apparatus with a quenching condenser according to any one of claims 1-5, characterized in that, The solid-liquid centrifuge includes an annular receiving tank, a centrifuge base located within the annular receiving tank, and a centrifugal settling zone and a centrifugal filtration zone located on top of the centrifuge base. The centrifuge base is driven to rotate by a motor, thereby causing the centrifugal settling zone and the centrifugal filtration zone to rotate at high speed. The top of the annular receiving tank has an opening to receive the liquid material ejected from the centrifugal filtration zone through its pores, and the bottom has a discharge outlet for liquid discharge and storage. The upper part of the centrifugal settling zone is the centrifugal filtration zone, which is equipped with a solid-liquid microporous filter plate so that the separated liquid ejected by centrifugation can enter the annular receiving tank and flow downwards along the channel inside the annular receiving tank for discharge.

7. The slag-free carbothermic magnesium smelting apparatus with a quenching condenser according to any one of claims 1-5, characterized in that, The second cooling chamber is also connected in sequence to a dust collector, an explosion-proof induced draft fan, and a by-product gas storage tank. The dust collector removes the carbon monoxide, and the by-product gas is stored in the storage tank by the explosion-proof induced draft fan.

8. A slag-free carbothermic magnesium smelting method with a quenching condenser, characterized in that, The slag-free carbothermic magnesium smelting apparatus with a quenching condenser as described in any one of claims 1-7 includes the following steps: Solid materials containing magnesium oxide and carbon reducing agent are added to the hollow top electrode of the magnesium smelting electric arc furnace and transported into the magnesium smelting electric arc furnace through low-pressure methane gas. The high-temperature electric arc radiation of the magnesium smelting electric arc furnace heats the solid materials to produce a carbothermic reduction reaction, generating a high-temperature furnace gas composed of magnesium vapor and carbon monoxide gas. High-temperature furnace gas enters the heat compensation chamber through the gas channel, and the heat compensation chamber compensates for the temperature to maintain it at the set temperature. High-temperature furnace gas enters the quenching and condensing unit through the heating chamber. Partially vaporized liquid hydrocarbons are injected into the quenching and condensing unit as the main gas through the coolant vaporization and insulation tank. They are then mixed with the high-temperature furnace gas through the corrugated nozzle to enhance momentum mixing. While mixing, the gas and liquid mixtures enter the quenching and condensing unit through the injection mixing chamber and Laval nozzle. The mixture undergoes isentropic expansion and does work, while being accelerated to multiple times the speed of sound and rapidly cooled. This causes the magnesium vapor in the furnace gas to be quenched and condensed, and the cooled and sublimated magnesium crystal particles are encapsulated by the liquid hydrocarbons and enter the first cooling chamber. The furnace gas and liquid hydrocarbons carrying magnesium crystal particles enter the first cooling chamber for cooling, which causes the vaporized liquid hydrocarbons in the furnace gas to cool, condense and drip down, and the vaporized liquid hydrocarbons are cooled and re-condensed into liquid, causing the liquid hydrocarbons carrying magnesium crystal particles to condense and collect at the bottom of the first cooling chamber. The remaining furnace gas and the remaining unliquefied liquid hydrocarbons enter the second cooling chamber for cooling and condensation, and collect at the bottom of the second cooling chamber. The carbon monoxide in the chamber is removed by dust removal and stored. The solid-liquid two-phase mixture inside the first cooling chamber is periodically discharged, and the liquid hydrocarbons and solids are separated by a solid-liquid centrifuge. Liquid hydrocarbons are repressurized and vaporized for storage in a coolant vaporization and insulation tank; The oily solid separated by centrifugation was distilled, and the gas produced by distillation was cooled in two stages at different temperatures to obtain pure crystalline magnesium and liquid hydrocarbons, respectively.

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