A vacuum internal heat refining magnesium system based on stable conduction of graphite electrode

Abstract

The present application belongs to the field of magnesium metallurgy and vacuum internal heat smelting technology, and discloses a vacuum internal heat smelting magnesium system based on stable conduction of graphite electrodes, which comprises a raw material pretreatment and closed supply module, a stable conduction of graphite electrodes module, a radiation conduction and collaborative heating module, a continuous vacuum reduction and condensation module, a waste heat gradient recovery module, a carbon dioxide recycling module and an intelligent production control module. Through dense and oxidation-resistant treatment of graphite electrodes, internal and external collaborative heating, double-gate closed feeding, staged vacuum extraction and vacuum transition discharge, stable conduction of graphite electrodes, uniform heating of magnesium smelting briquettes and vacuum maintenance of the whole process are realized, and at the same time, waste heat, carbon dioxide and reduction slag are recycled, thereby improving the magnesium smelting efficiency and energy utilization rate, reducing the production energy consumption and carbon emission.

Description

Technical Field

[0001] This invention belongs to the field of magnesium metallurgy and vacuum internal heating smelting technology, and particularly relates to a vacuum internal heating magnesium smelting system based on the stable conductivity of graphite electrodes. Background Technology

[0002] Magnesium metal is characterized by its low density, high specific strength, good thermal conductivity, and abundant reserves. It has wide applications in aerospace, rail transportation, automobile manufacturing, and electronic equipment. The magnesium smelting process requires the reduction of magnesium-containing raw materials, the transfer of magnesium vapor, and the condensation of metallic magnesium under high temperature and vacuum conditions. In order to reduce smelting energy consumption, shorten the reduction cycle, and reduce carbon emissions, it is necessary to establish an internal heat magnesium smelting production system that combines stable electrical conductivity, internal and external synergistic heating, continuous vacuum maintenance, and resource recycling capabilities.

[0003] When existing internal heating magnesium smelting equipment uses electrodes to input heat to the reactants, graphite electrodes are prone to oxidation, air ingress through pores, increased contact resistance, and localized temperature anomalies in high-temperature environments and at electrode penetration interfaces. The conductivity of the electrodes fluctuates with operating time. At the same time, the lack of coordinated control between external radiation heating and internal conductive heating easily leads to faster heating of the outer layer of the magnesium smelting lumps, slower heating of the center, and uneven temperature distribution in the reaction zone, affecting the stability of the reduction reaction and the service life of the graphite electrodes.

[0004] In the existing vacuum magnesium smelting process, the feeding, magnesium discharge, and slag discharge stages usually require the partial vacuum to be released and then re-vacuumed. The switching of production stages can easily cause air to enter, heat loss, and extended production cycles. At the same time, the waste heat generated by the raw material calcination tail gas, high-temperature reduction slag, reaction vessel outer wall, and magnesium vapor condensation process is not fully utilized according to temperature levels. The carbon dioxide and reduction slag generated by calcination are also not integrated into a synergistic recovery and utilization system, resulting in high energy consumption and carbon emissions per unit of metallic magnesium. Summary of the Invention

[0005] To address the above issues and overcome the shortcomings of existing technologies, this invention provides a vacuum internal heating magnesium smelting system based on stable conductivity of graphite electrodes. Utilizing the principles of dense, anti-oxidation treatment of graphite electrodes, synergistic heating through radiation conductivity, continuous vacuum sealing, and low-carbon resource recycling, this system achieves stable conductivity of graphite electrodes, simultaneous heating of the magnesium smelting lumps inside and outside the lumps, vacuum maintenance throughout the entire process from feeding to slag discharge, cascade recovery of waste heat, and carbon dioxide mineralization and fixation. This improves the stability of the reduction reaction and energy utilization, and solves the problems of graphite electrode oxidation, uneven heating of the lumps, repeated vacuum disruption during production, and high energy consumption and carbon emissions in the magnesium smelting process.

[0006] The technical solution adopted in this invention is as follows: A vacuum internal heating magnesium smelting system based on stable conductivity of graphite electrodes, comprising a raw material pretreatment and closed supply module, a graphite electrode stable conductivity module, a radiation conductivity synergistic heating module, a continuous vacuum reduction and condensation module, a waste heat cascade recovery module, a carbon dioxide recovery and utilization module, and an intelligent production control module.

[0007] The raw material pretreatment and closed supply module calcines, crushes, quantitatively feeds, mixes, briquettes, dries and preheats magnesium-containing raw materials, reducing agents and mineralizers to generate magnesium smelting briquettes, which are then transported to the vacuum reaction tank through a vacuum transition chamber, a first vacuum isolation valve, a second vacuum isolation valve and a feed pusher.

[0008] The graphite electrode stable conductivity module includes a graphite electrode, a conductive clamping assembly, an electrode sealing assembly, an electrode status acquisition assembly, and an anti-oxidation protection assembly. The graphite electrode includes an external conductive connection section, a can-penetrating sealing section, and an internal heating section.

[0009] The graphite electrode undergoes vacuum degassing, carbon impregnation, pressure infiltration, curing, and high-temperature carbonization treatments, which seal the internal openings and pores of the graphite electrode with carbonized filling material. A silicon carbide anti-oxidation protective layer is formed on the surface of the can-penetrating sealing section and the can-heating section, while the external conductive connection section retains the conductive contact surface that has been ground and cleaned.

[0010] The conductive clamping assembly adjusts the clamping state of the graphite electrode according to the conductive contact resistance and clamping pressure, and controls the temperature of the conductive contact area through the cooling channel. The electrode sealing assembly forms a double-layer sealing structure through the inner vacuum seal, the outer vacuum seal and the isolation cavity. The anti-oxidation protection assembly introduces inert protective gas into the isolation cavity.

[0011] The graphite electrode stable conductivity module generates a graphite electrode stable conductivity coefficient based on the current conductivity of the graphite electrode, conductive contact resistance, oxidation mass loss ratio, and axial temperature difference. It then adjusts the conductive clamping pressure, graphite electrode input current, and anti-oxidation protection status based on the graphite electrode stable conductivity coefficient.

[0012] The radiation-conductive synergistic heating module includes an external resistance radiation heating unit, an internal graphite electrode conductive heating unit, a material temperature field acquisition unit, a heat flow distribution analysis unit, and a heating power coordination unit.

[0013] The external resistance radiation heating unit provides radiant heat from outside the vacuum reaction vessel to the magnesium smelting material, while the internal graphite electrode conductive heating unit controls the paired graphite electrodes to be energized, so that the heating section inside the vessel generates Joule heat and transfers heat into the magnesium smelting material.

[0014] The lump temperature field acquisition unit collects the outer layer temperature, center temperature, axial temperature, and radial temperature of the magnesium smelting lump. The heat flow distribution analysis unit generates synergistic heating state data based on the external radiative heat flux density, graphite electrode input power, outer wall temperature of the vacuum reactor, and the temperature distribution of the magnesium smelting lump.

[0015] The heating power coordination unit generates a heating coordination coefficient based on the coordinated heating status data, and adjusts the external resistance radiation heating power and the internal graphite electrode conductive heating power according to the center temperature, outer layer temperature, maximum internal temperature difference and stable conductivity coefficient of the magnesium smelting material.

[0016] The continuous vacuum reduction and condensation module includes a special treatment unit for the vacuum reaction vessel, a staged vacuum pumping unit, a vacuum reduction control unit, a magnesium vapor directional transfer unit, a staged condensation unit, a closed magnesium discharge unit, and a closed slag discharge unit.

[0017] The special treatment unit for the vacuum reactor performs full penetration welding on the tank body welds, vacuum degassing treatment on the inner wall of the tank, and sets up a double-layer sealing structure and independent leak detection chamber at the feed port, slag outlet, magnesium vapor port and electrode installation port.

[0018] The staged vacuum pumping unit establishes the initial vacuum environment, discharges the gases released by the heated magnesium smelting lumps, and maintains the target vacuum pressure during the reduction reaction stage through the pre-vacuum pump group, medium vacuum pump group, and high vacuum pump group, respectively.

[0019] The magnesium vapor directional transfer unit transports magnesium vapor to the staged condensation unit through a high-temperature resistant vacuum pipeline equipped with heat-insulating heating components. The staged condensation unit completes the magnesium vapor diversion, metallic magnesium crystallization, and residual magnesium vapor collection through a high-temperature diversion zone, a medium-temperature crystallization zone, and a low-temperature collection zone.

[0020] The closed magnesium discharge unit and the closed slag discharge unit complete the discharge of metallic magnesium and reducing slag through a vacuum transition chamber, an inner isolation valve, an outer isolation valve and an independent vacuum port, respectively, so as to maintain a continuous vacuum environment during the feeding, reduction, magnesium vapor transfer, condensation, magnesium discharge and slag discharge processes.

[0021] The waste heat recovery module includes a high-temperature waste heat recovery unit, a medium-temperature waste heat recovery unit, a low-temperature waste heat recovery unit, a heat medium circulation unit, a heat storage unit, and a heat distribution unit.

[0022] The high-temperature waste heat recovery unit recovers waste heat from the high-temperature reduction slag and the tail gas from the calcination of raw materials; the medium-temperature waste heat recovery unit recovers waste heat from the outer wall of the vacuum reactor, the magnesium vapor condensation assembly, and the high-temperature resistant vacuum pipeline; and the low-temperature waste heat recovery unit recovers waste heat from the exhaust gas of the vacuum pump, the return water of the condensate cooling medium, and the cooling medium of the carbon dioxide compression equipment.

[0023] The heat distribution unit generates waste heat distribution data based on waste heat temperature, waste heat flow rate, target temperature of each heat application location and production stage, and distributes high-temperature waste heat to the raw material calcination and magnesium smelting pellet preheating process, medium-temperature waste heat to pellet drying and vacuum feeding preparation process, and low-temperature waste heat to the feeding silo insulation process.

[0024] The carbon dioxide recovery and utilization module includes a carbon dioxide gas collection unit, a dust removal and purification unit, a dehydration and compression unit, a carbon dioxide temporary storage unit, a reduction residue pretreatment unit, a mineralization and carbon fixation unit, and a carbon fixation product detection unit.

[0025] The carbon dioxide gas collection unit collects the carbon dioxide-containing tail gas generated during the raw material calcination process. The dust removal and purification unit and the dehydration and compression unit perform dust removal, purification, dehydration and compression treatment on the carbon dioxide-containing tail gas. The carbon dioxide temporary storage unit adjusts the carbon dioxide temporary storage amount and output flow rate according to the processing capacity of the mineralization and carbon fixation unit.

[0026] The reduction slag pretreatment unit cools, crushes, screens, and adjusts the moisture content of the reduction slag to generate mineralized raw materials. The mineralization and carbon fixation unit introduces carbon dioxide gas into the mineralized raw materials, causing the carbon dioxide to react with the calcium-containing and magnesium-containing components in the mineralized raw materials.

[0027] The carbon fixation product detection unit determines the carbon dioxide mineralization fixation state based on the changes in mass, carbonate content, and carbon dioxide concentration before and after mineralization treatment, and generates a low-carbon resource utilization coefficient by combining the waste heat reuse state.

[0028] The intelligent production control module includes a production data acquisition unit, a production status identification unit, a digital production model, a collaborative control unit, a fault diagnosis unit, a low-carbon evaluation unit, and a production traceability unit.

[0029] The production data acquisition unit collects raw material status data, graphite electrode status data, synergistic heating status data, vacuum reduction status data, magnesium vapor condensation status data, waste heat recovery status data, and carbon dioxide recovery status data, and establishes a production data sequence according to production batch and acquisition time.

[0030] The digital production model generates the estimated reduction completion time, estimated magnesium metal output, estimated unit energy consumption, estimated waste heat recovery, and estimated carbon dioxide fixation based on material balance, heat balance, electrical energy input, vacuum pressure changes, magnesium vapor generation rate, and carbon dioxide flow direction.

[0031] The collaborative control unit adjusts the feed rate of magnesium smelting pellets, the input current of graphite electrodes, the radiation heating power of the resistance furnace, the operating status of the vacuum pump group, the condensation temperature of magnesium vapor, the flow rate of waste heat transfer medium, and the input of carbon dioxide mineralization based on the magnesium smelting production forecast data.

[0032] The fault diagnosis unit identifies abnormalities in graphite electrode contact, graphite electrode oxidation, heating zone, vacuum leakage, magnesium vapor pipeline blockage, and condensation failure based on the graphite electrode's stable conductivity coefficient, heating coordination coefficient, vacuum continuity coefficient, magnesium vapor generation rate, and condensation temperature, and generates corresponding control commands.

[0033] The beneficial effects of this invention are as follows: (1) By utilizing the principles of dense treatment of graphite electrodes, surface anti-oxidation protection, double-layer vacuum sealing and inert gas isolation, real-time monitoring and closed-loop regulation of the conductive contact state, oxidation state and temperature state of graphite electrodes are realized, which improves the conductivity stability of graphite electrodes in high temperature vacuum environment and solves the problems of easy oxidation of graphite electrodes, increased contact resistance, gas ingress at the interface and local overheating.

[0034] (2) This invention utilizes the principle of coordinated heating by external resistance radiation heating and internal graphite electrode conductive heating. Based on the temperature field of magnesium smelting material and the stable conductive state of graphite electrodes, the radiation heating power and conductive heating power are dynamically allocated, thereby realizing the coordinated control of external radiation heating and internal Joule heating of magnesium smelting material. This solves the problems of long heat transfer path of single external heating, slow heating of the center of the material and uneven temperature distribution.

[0035] (3) By utilizing the principles of double-gate closed feeding, staged vacuuming, vacuum transition magnesium discharge, vacuum transition slag discharge, waste heat recovery and carbon dioxide mineralization and carbon fixation, continuous vacuum is achieved throughout the entire process of feeding, reduction, magnesium vapor transfer, condensation, magnesium discharge and slag discharge. It also realizes the recycling of waste heat and carbon dioxide resources at different temperature levels, solving the problems of repeated vacuum destruction, low thermal energy utilization and high carbon emissions in the production process. Attached Figure Description

[0036] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the invention and do not constitute a limitation thereof.

[0037] Figure 1 This is a flowchart of the overall process of the vacuum internal heating magnesium smelting system of the present invention; Figure 2 This is a flowchart of the stable conductivity control process for the graphite electrode of the present invention. Figure 3 This is a flowchart of the intelligent production control process of the present invention. Detailed Implementation

[0038] Example 1, see Figures 1-3The present invention provides a vacuum internal heating magnesium smelting system based on stable conductivity of graphite electrodes, comprising a raw material pretreatment and closed supply module, a graphite electrode stable conductivity module, a radiation conductivity synergistic heating module, a continuous vacuum reduction and condensation module, a waste heat cascade recovery module, a carbon dioxide recovery and utilization module, and an intelligent production control module.

[0039] The raw material pretreatment and closed supply module calcines, crushes, quantitatively feeds, mixes, briquettes, dries, and preheats magnesium-containing raw materials, reducing agents, and mineralizing agents to generate magnesium smelting pellets, which are then transported to the continuous vacuum reduction and condensation module through a closed feeding channel.

[0040] The graphite electrode stable conductivity module includes a graphite electrode, a conductive clamping assembly, an electrode sealing assembly, an electrode status acquisition assembly, and an anti-oxidation protection assembly. The graphite electrode undergoes vacuum impregnation, carbonization densification treatment, and surface anti-oxidation treatment. The graphite electrode stable conductivity module adjusts the conductive clamping pressure, electrode input current, and anti-oxidation protection status according to the conductivity, oxidation, contact, and temperature status of the graphite electrode.

[0041] The radiant and conductive co-heating module includes a resistance furnace radiant heating component, a graphite electrode internal heating component, a furnace temperature acquisition component, a heat flux density acquisition component, and a power distribution component. The resistance furnace radiant heating component provides radiant heat from the outside of the vacuum reaction vessel to the magnesium smelting material. The graphite electrode internal heating component generates Joule heat through the graphite electrode and transfers heat into the magnesium smelting material. The power distribution component allocates the resistance furnace radiant heating power and the graphite electrode conductive heating power according to the temperature distribution, heating rate, and reduction stage of the magnesium smelting material.

[0042] The continuous vacuum reduction and condensation module includes a vacuum reaction vessel, a closed feeding assembly, a vacuum reduction assembly, a magnesium vapor transfer assembly, a magnesium vapor condensation assembly, a closed magnesium discharge assembly, a closed slag discharge assembly, and a staged vacuum pumping assembly. The continuous vacuum reduction and condensation module maintains a continuous vacuum environment during the feeding of magnesium smelting pellets, vacuum reduction, magnesium vapor transfer, magnesium vapor condensation, collection of metallic magnesium, and discharge of reduction slag.

[0043] The waste heat recovery module recovers waste heat from raw material calcination tail gas, waste heat from the outer wall of the vacuum reactor, waste heat from magnesium vapor condensation, waste heat from reduction slag, and waste heat from vacuum pump exhaust. Based on the temperature level of different waste heat sources, the recovered heat is distributed to the processes of raw material preheating, magnesium smelting pellet drying, feed silo insulation, and heat medium energy storage.

[0044] The carbon dioxide recovery and utilization module collects carbon dioxide-containing tail gas generated during the calcination process of raw materials, performs dust removal, cooling, dehydration, purification, compression and temporary storage on the carbon dioxide-containing tail gas, and then transports the purified carbon dioxide gas to the reducing slag mineralization and carbon fixation component, so that the carbon dioxide gas reacts with the calcium-containing and magnesium-containing components in the reducing slag.

[0045] The intelligent production control module collects raw material status data, graphite electrode status data, synergistic heating status data, vacuum reduction status data, magnesium vapor condensation status data, waste heat recovery status data, and carbon dioxide recovery status data to establish a magnesium smelting production status model. Based on the magnesium smelting production status model, it generates feed control data, graphite electrode conductivity control data, synergistic heating control data, vacuum control data, condensation control data, waste heat distribution data, and carbon dioxide recovery control data.

[0046] In this embodiment, after the magnesium smelting production is started, the raw material pretreatment and closed supply module first processes the magnesium-containing raw materials into magnesium smelting pellets. The closed feeding component then sends the magnesium smelting pellets into a vacuum reaction vessel. The staged vacuum pumping component establishes a vacuum reduction environment. The resistance furnace radiation heating component and the graphite electrode internal heating component heat the magnesium smelting pellets together. After the magnesium smelting pellets reach the reduction reaction conditions, magnesium vapor is generated. The magnesium vapor enters the magnesium vapor condensation component through the magnesium vapor transfer component to form metallic magnesium. The reduction slag is discharged through the closed slag discharge component. The waste heat cascade recovery module and the carbon dioxide recovery and utilization module simultaneously recover heat and carbon dioxide resources.

[0047] Through the above structure, this invention utilizes a graphite electrode that has undergone densification and anti-oxidation treatment to establish a stable conductive channel, and coordinates the conductive internal heat of the graphite electrode with the external radiant heat of the resistance furnace to ensure that the magnesium smelting lumps are heated simultaneously from the inside and outside. At the same time, a continuous vacuum production process is formed through closed feeding, vacuum reduction, vacuum condensation, closed magnesium discharge, and closed slag discharge, and waste heat and carbon dioxide are recovered and utilized, solving the problems of high-temperature oxidation of graphite electrodes, uneven temperature distribution of magnesium smelting lumps, repeated vacuum destruction in the production process, and low utilization rate of energy and carbon resources.

[0048] Example 2: Based on all the above examples, the raw material pretreatment and closed supply module specifically includes a raw material calcination unit, a raw material crushing unit, a quantitative batching unit, a mixing and briquetting unit, a briquetting drying unit, a vacuum feeding preparation unit, and a double-gate closed feeding unit.

[0049] The raw material calcination unit uses electric heating to calcine magnesium-containing raw materials, thereby decomposing the magnesium-containing raw materials and generating calcined material. At the same time, the carbon dioxide-containing exhaust gas generated during calcination is transported to the carbon dioxide recovery and utilization module.

[0050] The raw material crushing unit processes the calcined material to a preset particle size range. The quantitative batching unit measures the calcined material, reducing agent, and mineralizing agent according to the set ratio. The mixing and briquetting unit mixes the measured calcined material, reducing agent, and mineralizing agent evenly and presses them to form magnesium smelting briquettes.

[0051] The briquette drying unit receives the recovered heat from the waste heat recovery module to dry and preheat the magnesium briquette, so that the moisture content and feed temperature of the magnesium briquette reach the set range, and the amount of gas released after the magnesium briquette enters the vacuum reactor is reduced.

[0052] The vacuum feeding preparation unit includes an atmospheric pressure storage silo, a vacuum transition silo, a feed pusher, a first vacuum isolation valve, and a second vacuum isolation valve. The first vacuum isolation valve is located between the atmospheric pressure storage silo and the vacuum transition silo, and the second vacuum isolation valve is located between the vacuum transition silo and the vacuum reaction vessel.

[0053] Before the magnesium smelting briquettes enter the vacuum transition chamber, the second vacuum isolation valve remains closed while the first vacuum isolation valve is open. After the magnesium smelting briquettes enter the vacuum transition chamber from the atmospheric pressure storage silo, the first vacuum isolation valve closes, and the staged vacuum pumping assembly reduces the pressure inside the vacuum transition chamber to the feed equalization pressure. Once the pressure inside the vacuum transition chamber reaches the feed equalization pressure, the second vacuum isolation valve opens, and the feed pusher pushes the magnesium smelting briquettes into the vacuum reaction vessel.

[0054] After the magnesium smelting briquettes enter the vacuum reactor, the second vacuum isolation valve closes, the vacuum transition chamber performs pressure equalization, and then the first vacuum isolation valve opens to receive the next batch of magnesium smelting briquettes, thus completing the batch continuous feeding without removing the vacuum from the vacuum reactor.

[0055] The dual-gate sealed feeding unit is equipped with an independent leak detection channel between the first vacuum isolation valve and the second vacuum isolation valve. The intelligent production control module judges the sealing status of the first vacuum isolation valve and the second vacuum isolation valve based on the pressure change of the leak detection channel. If the sealing status does not meet the feeding requirements, the feeding is stopped and the vacuum transition chamber is controlled to be evacuated again.

[0056] The raw material pretreatment and closed supply module sends the feed batch, moisture content, temperature, vacuum transition chamber pressure, and isolation valve sealing status of the magnesium smelting briquette to the intelligent production control module. The intelligent production control module generates the feed time and quantity of the next batch of magnesium smelting briquette based on the remaining amount of briquette in the vacuum reactor and the progress of the reduction reaction.

[0057] Through the above processes, the raw material pretreatment and closed supply module can complete raw material calcination, particle size control, quantitative batching, mixing and briquetting, briquette drying and vacuum transition feeding, so that magnesium briquettes can enter the vacuum reactor without disrupting the vacuum state of the vacuum reactor, solving the problem of extended production cycle and increased energy consumption caused by the need to remove and re-vacuum in the traditional feeding process.

[0058] Example 3: Based on all the above examples, the graphite electrode stable conductivity module specifically includes a graphite electrode densification treatment unit, a graphite electrode anti-oxidation treatment unit, a conductive clamping unit, an electrode can sealing unit, an inert gas isolation unit, and a graphite electrode state judgment unit.

[0059] The graphite electrode includes an external conductive connection section, a can-penetrating sealing section, and an internal heating section. The external conductive connection section is connected to the conductive clamping unit, the can-penetrating sealing section passes through the electrode mounting interface of the vacuum reaction vessel, and the internal heating section extends to the heating area where the magnesium smelting lumps are located.

[0060] The graphite electrode densification unit sequentially performs vacuum degassing, carbon impregnation, pressure infiltration, curing, and high-temperature carbonization on the graphite electrode substrate. This process seals the internal openings and pores of the graphite electrode with carbonized filling material, reducing the rate at which external gas diffuses along the graphite electrode pores into the can sealing section and the can heating section.

[0061] The graphite electrode anti-oxidation treatment unit forms a silicon carbide anti-oxidation protective layer on the surface of the can-penetrating sealing section and the can-in-can heating section. The external conductive connection section retains the conductive contact surface, which is then ground and cleaned before being attached to the conductive clamping unit.

[0062] The conductive clamping unit includes a conductive sleeve, a clamping drive, a cooling channel, a contact resistance detection device, and a clamping pressure detection device. The clamping drive adjusts the clamping force of the conductive sleeve on the external conductive connection section according to the conductive contact resistance and clamping pressure. The cooling channel controls the temperature of the conductive contact area within the allowable temperature range of the conductive clamping unit.

[0063] The electrode can-penetrating sealing unit includes an inner vacuum seal, an outer vacuum seal, and an isolation cavity located between the inner and outer vacuum seals. The inert gas isolation unit inputs inert protective gas into the isolation cavity to prevent external air from directly entering the vacuum reaction vessel. At the same time, the electrode can-penetrating sealing status is determined by the pressure change in the isolation cavity.

[0064] The graphite electrode state determination unit collects the current conductivity, conductive contact resistance, graphite electrode oxidation mass loss ratio, and graphite electrode axial temperature difference of the graphite electrode, and calculates the stable conductivity coefficient of the graphite electrode based on the collected results. The formula for the stable conductivity coefficient of the graphite electrode is as follows:

[0065] In the formula, This represents the stable conductivity coefficient of the graphite electrode. This indicates the current conductivity of the graphite electrode. This indicates the initial conductivity of the graphite electrode. Indicates the resistance of conductive contact. This indicates the upper limit of the conductive contact resistance. Indicates the proportion of mass loss due to oxidation of graphite electrodes This indicates the upper limit of the proportion of mass loss due to oxidation. This indicates the axial temperature difference of the graphite electrode. This indicates the upper limit of the axial temperature difference of the graphite electrode. , , and These represent the weight coefficients of the corresponding state factors.

[0066] When the stable conductivity coefficient of the graphite electrode reaches the normal conductivity threshold, the graphite electrode stable conductivity module maintains the current conductivity clamping pressure and graphite electrode input current. When the stable conductivity coefficient of the graphite electrode is lower than the conductivity warning threshold, the graphite electrode state judgment unit controls the conductivity clamping unit to readjust the clamping pressure and controls the radiation conductivity co-heating module to reduce the graphite electrode input current.

[0067] When the stable conductivity coefficient of the graphite electrode falls below the conductivity stop threshold, the intelligent production control module stops the conductive heating of the graphite electrode, increases the external resistance radiation heating power to maintain the temperature inside the vacuum reaction vessel, and generates a graphite electrode maintenance command.

[0068] Regarding parameter adjustments: When the conductive contact resistance of the graphite electrode continues to increase, increase the weight corresponding to the conductive contact resistance; when the oxidation mass loss ratio of the graphite electrode continues to increase, increase the weight corresponding to the oxidation mass loss ratio; when the axial temperature difference of the graphite electrode continues to increase, increase the weight corresponding to the axial temperature difference. The adjustment range of each weight coefficient is jointly limited by the graphite electrode material parameters and production calibration parameters.

[0069] Through the above treatments, the graphite electrode stable conductivity module can maintain the conductivity stability of the graphite electrode by using densification treatment, anti-oxidation protection, double-layer vacuum sealing, inert gas isolation, and closed-loop regulation of conductivity state, thus solving the problems of oxidation, increased contact resistance, and local overheating of graphite electrodes in high-temperature environments and vacuum interface locations.

[0070] Example 4: Based on all the above examples, the radiation-conductive synergistic heating module specifically includes an external resistance radiation heating unit, an internal graphite electrode conductive heating unit, a material temperature field acquisition unit, a heat flow distribution analysis unit, and a heating power coordination unit.

[0071] An external resistance radiation heating unit is set on the outer periphery of the vacuum reaction vessel and includes a resistance heating element, a radiation reflection layer, a heat insulation layer, and a zone power adjustment component. The zone power adjustment component divides the vacuum reaction vessel into a preheating heating zone, a reduction heating zone, and a heat insulation heating zone along the axial direction, and adjusts the radiation heating power of the preheating heating zone, the reduction heating zone, and the heat insulation heating zone respectively.

[0072] The internal graphite electrode conductive heating unit controls the pair of graphite electrodes to be energized, so that the heating section inside the tank of the graphite electrodes generates Joule heat. The heating section inside the tank transfers heat to the interior of the magnesium smelting material through thermal radiation and contact heat conduction.

[0073] The lump temperature field acquisition unit collects the outer layer temperature, center temperature, axial temperature and radial temperature of magnesium smelting lump, and establishes lump temperature field data according to different acquisition locations.

[0074] The heat flow distribution analysis unit collects external radiative heat flow density, graphite electrode input power, vacuum reactor outer wall temperature, and magnesium smelting material temperature distribution, and generates synergistic heating state data based on the collected results.

[0075] The heating power coordination unit calculates the heating coordination coefficient based on the coordinated heating status data. The formula for the heating coordination coefficient is as follows:

[0076] In the formula, Indicates the heating synergy coefficient. This indicates the effective heat transferred to the magnesium smelting briquette by the conductive heating of the graphite electrode. This indicates the effective heat transferred by the electric resistance furnace's radiant heating to the magnesium smelting briquette. Indicates the total input calories. This indicates the maximum temperature difference inside the magnesium smelting pellet. This indicates the allowable temperature difference inside the magnesium smelting pellets. This indicates the system's power loss due to heat dissipation. Indicates the system input power. , , and These represent the weighting coefficients of the corresponding heating factors.

[0077] When the temperature at the center of the magnesium smelting pellet is lower than the temperature at the outer layer, the heating power coordination unit increases the conductive heating power of the graphite electrode and decreases the external resistance radiation heating power. When the temperature at the outer layer of the magnesium smelting pellet is lower than the temperature at the center, the heating power coordination unit increases the external resistance radiation heating power and decreases the conductive heating power of the graphite electrode.

[0078] When the magnesium smelting briquette enters the preheating stage, the external resistance radiation heating unit undertakes the main temperature rise load. When the magnesium smelting briquette enters the reduction stage, the internal graphite electrode conductive heating unit increases the input power to make the internal temperature of the magnesium smelting briquette reach the reduction reaction temperature. When the magnesium smelting briquette enters the heat preservation stage, the heating power coordination unit maintains the external radiation heating power and the internal conductive heating power according to the magnesium vapor generation rate.

[0079] When the heating coordination coefficient is lower than the coordination warning threshold, the heating power coordination unit reallocates the external resistance radiation heating power and the internal graphite electrode conductive heating power according to the center temperature, outer layer temperature and stable conductivity coefficient of the magnesium smelting material. When the heating coordination coefficient is lower than the coordination stop threshold, the intelligent production control module stops feeding and puts the vacuum reaction vessel into the heat preservation and inspection state.

[0080] Regarding parameter adjustments: When the maximum temperature difference inside the magnesium smelting briquette continues to increase, increase the weight corresponding to the internal temperature difference; when the stable conductivity coefficient of the graphite electrode decreases, lower the upper limit of the internal graphite electrode's conductive heating power; when the heat loss from the outer wall of the vacuum reactor increases, increase the weight corresponding to the system's heat loss power.

[0081] Through the above processing, the radiation-conductive synergistic heating module can form a bidirectional heat input through external resistance radiation heating and internal graphite electrode conductive heating, and dynamically distribute the heating power according to the temperature field of the magnesium smelting material, thus solving the problems of long heat transfer path, slow temperature rise in the center of the magnesium smelting material, and large local temperature difference caused by the single external heating method.

[0082] Example 5: Based on all the above examples, the continuous vacuum reduction and condensation module specifically includes a special treatment unit for a vacuum reaction vessel, a staged vacuum pumping unit, a vacuum reduction control unit, a magnesium vapor directional transfer unit, a staged condensation unit, a sealed magnesium discharge unit, and a sealed slag discharge unit.

[0083] The special treatment unit for the vacuum reactor performs full penetration welding on the tank body welds, vacuum degassing treatment on the inner wall of the tank, and sets up a double-layer sealing structure for the feed port, slag outlet, magnesium vapor port and electrode installation port, with an independent leak detection chamber between the double-layer sealing structure.

[0084] After the vacuum reactor is assembled, a helium mass spectrometry leak test is performed. The intelligent production control module generates vacuum seal calibration data based on the leak rate of the tank welds, the leak rate of the interfaces, and the pressure holding status of the leak test chamber. If the vacuum seal calibration data does not meet the production requirements, the vacuum reactor is prohibited from entering the magnesium smelting production state.

[0085] The staged vacuum pumping unit includes a pre-vacuum pump group, a medium vacuum pump group, a high vacuum pump group, a vacuum buffer tank, and a vacuum valve group. The pre-vacuum pump group reduces the initial pressure of the vacuum reaction tank, the medium vacuum pump group discharges the gas released during the heating of the magnesium smelting lumps, and the high vacuum pump group maintains the target vacuum pressure during the reduction reaction stage and the magnesium vapor transfer stage.

[0086] The vacuum reduction control unit receives the temperature of the magnesium smelting briquette, the pressure of the vacuum reactor, and the rate of magnesium vapor generation. When the temperature of the magnesium smelting briquette reaches the reduction reaction temperature and the pressure of the vacuum reactor reaches the target vacuum pressure, a reduction start state is generated. When the rate of magnesium vapor generation decreases to the reduction completion judgment range, a reduction end state is generated.

[0087] The magnesium vapor directional transfer unit is connected to the vacuum reaction vessel and the staged condensation unit through a high-temperature resistant vacuum pipeline. The high-temperature resistant vacuum pipeline is equipped with heat-insulating heating components to keep the magnesium vapor in a gaseous state before entering the staged condensation unit.

[0088] The staged condensation unit includes a high-temperature guiding zone, a medium-temperature crystallization zone, and a low-temperature trapping zone. The high-temperature guiding zone reduces the premature condensation of magnesium vapor at the inlet, the medium-temperature crystallization zone causes magnesium vapor to form metallic magnesium crystals, and the low-temperature trapping zone traps residual magnesium vapor that did not condense in the medium-temperature crystallization zone.

[0089] The closed magnesium discharge unit and the closed slag discharge unit are respectively equipped with a vacuum transition chamber, an inner isolation valve, an outer isolation valve, and an independent vacuum port. After the metallic magnesium and the reducing slag enter the corresponding vacuum transition chamber, the inner isolation valve is closed, and then the outer isolation valve is opened through the pressure equalization operation, so that the magnesium discharge process and the slag discharge process do not disrupt the vacuum environment of the vacuum reactor.

[0090] The vacuum reduction control unit calculates the vacuum continuity maintenance coefficient based on the vacuum reaction vessel pressure deviation, system leakage rate, number of abnormal vacuum valve operations, and vacuum recovery time. The formula for the vacuum continuity maintenance coefficient is as follows:

[0091] In the formula, Indicates the vacuum continuity coefficient. This indicates the current pressure of the vacuum reactor. Indicates the target vacuum pressure. Indicates the allowable pressure deviation. Indicates the system leakage rate. Indicates the allowable leakage rate. Indicates the number of times the vacuum valve has malfunctioned. Indicates the number of exceptions allowed. Indicates vacuum recovery time. Indicates the allowable vacuum recovery time , , and These represent the weighting coefficients for the corresponding vacuum factors.

[0092] When the vacuum continuity coefficient is lower than the vacuum warning threshold, the staged vacuum pumping unit increases the operating power of the corresponding vacuum pump group and shuts down unnecessary vacuum branches. When the vacuum continuity coefficient is lower than the vacuum stop threshold, the intelligent production control module stops feeding and heating, and controls the vacuum valve group to isolate the abnormal area.

[0093] Regarding parameter adjustments: Increase the target extraction capacity when the magnesium vapor generation rate increases; reduce the allowable pressure deviation before the start of the feeding and slag discharge processes; and increase the weight corresponding to the system leakage rate when the electrode can sealing status fluctuates.

[0094] Through the above processes, the continuous vacuum reduction and condensation module can keep the feeding, reduction, magnesium vapor transfer, magnesium vapor condensation, magnesium discharge and slag discharge in a continuous vacuum environment. It maintains vacuum stability through double-layer sealing, independent leak detection and staged vacuuming, solving the problem of air entering the vacuum reaction vessel and repeated vacuuming caused by production process switching.

[0095] Example 6: This example is based on all the above examples. The waste heat cascade recovery module specifically includes a high-temperature waste heat recovery unit, a medium-temperature waste heat recovery unit, a low-temperature waste heat recovery unit, a heat medium circulation unit, a heat storage unit, and a heat distribution unit.

[0096] The high-temperature waste heat recovery unit collects waste heat from the high-temperature reduction slag and raw material calcination tail gas, and transfers the recovered heat to the raw material calcination unit and the magnesium smelting pellet preheating process.

[0097] The medium-temperature waste heat recovery unit collects waste heat from the outer wall of the vacuum reaction vessel, the magnesium vapor condensation assembly, and the high-temperature resistant vacuum pipeline, and transfers the recovered heat to the briquette drying unit and the vacuum feeding preparation unit.

[0098] The low-temperature waste heat recovery unit collects waste heat from vacuum pump exhaust, condensate cooling medium return water, and carbon dioxide compression equipment cooling medium, and transfers the recovered heat to the feed silo insulation and low-temperature heat transfer medium system.

[0099] The heat medium circulation unit is equipped with a high-temperature heat medium circuit, a medium-temperature heat medium circuit, and a low-temperature heat medium circuit. Heat exchange occurs between the high-temperature heat medium circuit, the medium-temperature heat medium circuit, and the low-temperature heat medium circuit, and the flow direction of heat at different temperature levels is controlled by a flow regulating valve.

[0100] The heat storage unit stores recovered heat when the heat generated by the magnesium smelting system is higher than the immediate heat consumption, and releases the stored heat when the immediate heat consumption of the magnesium smelting system is higher than the current recovered heat.

[0101] The heat distribution unit generates waste heat distribution data based on waste heat temperature, waste heat flow rate, target temperature of each heat application location and production stage, and prioritizes the distribution of high-temperature waste heat to the raw material calcination and magnesium smelting pellet preheating process, the distribution of medium-temperature waste heat to the pellet drying and vacuum feeding preparation process, and the distribution of low-temperature waste heat to the feeding silo insulation process.

[0102] When the heat demand of the raw material calcination unit increases, the heat distribution unit increases the heat medium flow rate from the high-temperature heat medium circuit to the raw material calcination unit. When the heat demand of the agglomerate drying unit increases, the heat distribution unit increases the heat medium flow rate from the medium-temperature heat medium circuit to the agglomerate drying unit. When the heat demand at each heat application location is lower than the waste heat recovery amount, the heat distribution unit transfers the remaining heat to the heat storage unit.

[0103] The waste heat cascade recovery module sends the temperature, flow rate, recovered heat, reused heat, and stored heat of each waste heat source to the intelligent production control module, which adjusts the priority of waste heat allocation according to the current production stage.

[0104] Through the above processing, the waste heat cascade recovery module can recover, store and redistribute the heat in the magnesium smelting process according to the waste heat temperature level, reduce the direct cooling and emission of high-grade heat, and solve the problems of scattered waste heat sources, mismatch between recovered heat and heat demand, and high system power consumption.

[0105] Example 7: This example is based on all the above examples. The carbon dioxide recovery and utilization module specifically includes a carbon dioxide gas collection unit, a dust removal and purification unit, a dehydration and compression unit, a carbon dioxide temporary storage unit, a reduction residue pretreatment unit, a mineralization and carbon fixation unit, and a carbon fixation product detection unit.

[0106] The carbon dioxide gas collection unit collects the carbon dioxide-containing exhaust gas output from the raw material calcination unit and generates carbon dioxide source data based on the flow rate, temperature, pressure, and carbon dioxide concentration of the exhaust gas.

[0107] The dust removal and purification unit removes particulate matter and gaseous impurities from the carbon dioxide-containing exhaust gas. The dehydration and compression unit reduces the moisture content of the purified carbon dioxide gas and increases the carbon dioxide gas pressure. The carbon dioxide temporary storage unit adjusts the temporary storage amount and output flow rate of the carbon dioxide gas according to the processing capacity of the mineralization and carbon fixation unit.

[0108] The reduction slag pretreatment unit receives the reduction slag output from the closed slag discharge unit and cools, crushes, screens, and adjusts the moisture content of the reduction slag to generate mineral raw materials.

[0109] The mineralization and carbon fixation unit introduces carbon dioxide gas into the mineralization raw materials, causing the carbon dioxide to react with the calcium-containing and magnesium-containing components in the raw materials. The mineralization and carbon fixation process is adjusted according to the mineralization reaction temperature, mineralization reaction pressure, carbon dioxide input flow rate, and mineralization reaction time.

[0110] The carbon sequestration product detection unit detects the changes in mass, carbonate content, and carbon dioxide concentration of the mineralized raw materials before and after processing, and calculates the low-carbon resource utilization coefficient based on the detection results. The formula for the low-carbon resource utilization coefficient is as follows:

[0111] In the formula, Indicates the low-carbon resource utilization coefficient. This indicates the heat recovered and reused by the waste heat recovery module. This indicates the total energy input to the magnesium smelting system. Indicates the mass of carbon dioxide recovered. This indicates the mass of carbon dioxide produced during the calcination process of the raw materials. This indicates the mass of carbon dioxide that has been mineralized and fixed. This indicates the quality of mineralized products that meet the requirements for carbon sequestration products. This indicates the quality of the reduction slag involved in the mineralization process. , , and These represent the weight coefficients of the corresponding resource utilization factors.

[0112] When the low-carbon resource utilization coefficient reaches the set value, the carbon dioxide recovery and utilization module maintains the current waste heat utilization state and mineralization and carbon fixation state. When the low-carbon resource utilization coefficient is lower than the set value, the intelligent production control module determines the limiting link based on the waste heat utilization ratio, carbon dioxide recovery ratio, carbon dioxide mineralization and fixation ratio and qualified carbon fixation product ratio, and adjusts the heat distribution, carbon dioxide compression flow rate and mineralization reaction parameters.

[0113] Regarding parameter adjustments: When the carbon dioxide recovery ratio decreases, increase the weight corresponding to the carbon dioxide recovery ratio; when the calcium and magnesium components in the mineralized raw materials decrease, extend the mineralization reaction time; when the carbonate content of the carbon fixation product decreases, increase the carbon dioxide input pressure and the moisture content of the mineralized raw materials.

[0114] Through the above processing, the carbon dioxide recovery and utilization module can mineralize and combine the carbon dioxide generated from the calcination of raw materials with the magnesium smelting reduction slag, realizing the collection, purification, compression, temporary storage and solidification of carbon dioxide, thus solving the problems of direct carbon dioxide emissions and insufficient resource utilization of reduction slag in the magnesium smelting production process.

[0115] Example 8: Based on all the above examples, the intelligent production control module specifically includes a production data acquisition unit, a production status identification unit, a digital production model, a collaborative control unit, a fault diagnosis unit, a low-carbon evaluation unit, and a production traceability unit.

[0116] The production data acquisition unit collects raw material status data, graphite electrode status data, synergistic heating status data, vacuum reduction status data, magnesium vapor condensation status data, waste heat recovery status data, and carbon dioxide recovery status data, and establishes a production data sequence according to production batch and acquisition time.

[0117] The raw material status data includes raw material particle size, raw material ratio, agglomerate moisture content, agglomerate temperature, and agglomerate feed rate. The graphite electrode status data includes graphite electrode stable conductivity coefficient, conductive contact resistance, graphite electrode temperature, and clamping pressure. The synergistic heating status data includes heating synergistic coefficient, magnesium smelting agglomerate temperature, and heating power distribution results.

[0118] The vacuum reduction status data includes the vacuum continuity maintenance coefficient, vacuum reactor pressure, system leakage rate, magnesium smelting briquette reduction stage, and magnesium vapor generation rate. The magnesium vapor condensation status data includes the temperature of the high-temperature guiding zone, the temperature of the medium-temperature crystallization zone, the temperature of the low-temperature collection zone, and the amount of metallic magnesium collected.

[0119] Waste heat recovery status data includes waste heat source temperature, waste heat flow rate, waste heat recovery amount, reused heat and stored heat. Carbon dioxide recovery status data includes carbon dioxide-containing exhaust gas flow rate, carbon dioxide concentration, recovered carbon dioxide mass, mineralized fixed carbon dioxide mass and low-carbon resource utilization coefficient.

[0120] The production status identification unit identifies the raw material preparation status, closed feeding status, heating status, vacuum reduction status, magnesium vapor condensation status, closed magnesium discharge status, closed slag discharge status, waste heat recovery status, and carbon dioxide mineralization status based on the production data sequence.

[0121] The digital production model generates magnesium smelting production forecast data based on material balance, heat balance, power input, vacuum pressure changes, magnesium vapor generation rate, and carbon dioxide flow direction. The magnesium smelting production forecast data includes the estimated reduction completion time, the estimated metallic magnesium output, the estimated unit energy consumption, the estimated waste heat recovery, and the estimated carbon dioxide fixation.

[0122] The collaborative control unit adjusts the feed rate of magnesium smelting pellets, the input current of graphite electrodes, the radiation heating power of the resistance furnace, the operating status of the vacuum pump group, the condensation temperature of magnesium vapor, the flow rate of waste heat transfer medium, and the input of carbon dioxide mineralization based on the magnesium smelting production forecast data.

[0123] The fault diagnosis unit identifies abnormal graphite electrode contact, graphite electrode oxidation, heating zone, vacuum leakage, magnesium vapor pipeline blockage, and condensation failure based on the graphite electrode's stable conductivity coefficient decrease, heating coordination coefficient decrease, vacuum continuity maintenance coefficient decrease, magnesium vapor generation rate abnormal, and condensation temperature abnormal, and generates corresponding control commands.

[0124] When a graphite electrode contact abnormality occurs, the collaborative control unit adjusts the conductive clamping pressure and reduces the graphite electrode input current. When a heating zone abnormality occurs, the collaborative control unit redistributes the radiant heating power of the preheating heating zone, the reduction heating zone, and the heat preservation heating zone. When a vacuum leakage abnormality occurs, the collaborative control unit shuts down the abnormal vacuum branch and increases the operating power of the corresponding vacuum pump group.

[0125] When a blockage occurs in the magnesium vapor pipeline, the coordinating control unit increases the heat preservation and heating power of the high-temperature vacuum pipeline and reduces the heating power of the magnesium smelting lumps. When a condensation failure occurs, the coordinating control unit adjusts the condensation temperature of the medium-temperature crystallization zone and the low-temperature collection zone and reduces the magnesium vapor input rate.

[0126] The low-carbon evaluation unit generates production low-carbon evaluation results based on the unit magnesium metal electricity consumption, waste heat reuse ratio, carbon dioxide recovery ratio, carbon dioxide mineralization and fixation ratio, and reduction slag resource utilization ratio, and adjusts the heating power allocation and waste heat allocation strategy for the next production batch based on the production low-carbon evaluation results.

[0127] The production traceability unit records the source of raw materials for each production batch, the batch of graphite electrode processing, the graphite electrode running time, changes in heating power, changes in vacuum pressure, magnesium metal output, unit energy consumption, waste heat recovery, carbon dioxide recovery, carbon dioxide fixation, and abnormal handling results, forming a magnesium smelting production traceability file.

[0128] Through the above processing, the intelligent production control module can uniformly monitor and coordinate the raw material supply, graphite electrode conductivity, radiation conductivity synergistic heating, continuous vacuum maintenance, magnesium vapor condensation, waste heat recovery, and carbon dioxide utilization, forming a vacuum internal heat magnesium smelting production system that is monitorable, predictable, controllable, and traceable.

Claims

1. A vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes, comprising a raw material pretreatment and closed supply module, a graphite electrode stable electrical conductivity module, a radiation electrical conductivity synergistic heating module, a continuous vacuum reduction and condensation module, a waste heat cascade recovery module, a carbon dioxide recovery and utilization module, and an intelligent production control module, characterized in that: The raw material pretreatment and closed supply module pretreats magnesium-containing raw materials, reducing agents and mineralizing agents to generate magnesium smelting pellets, and transports the magnesium smelting pellets to the continuous vacuum reduction and condensation module while maintaining the vacuum state of the vacuum reactor. The graphite electrode stabilizing conductivity module performs densification treatment, anti-oxidation treatment, conductive clamping and can sealing on the graphite electrode, generates a graphite electrode stabilizing conductivity coefficient based on the graphite electrode state data, and adjusts the conductivity state of the graphite electrode based on the graphite electrode stabilizing conductivity coefficient. The radiation and conductivity co-heating module provides radiant heat from outside the vacuum reaction vessel to the magnesium smelting lumps and conductive heat to the inside of the magnesium smelting lumps through graphite electrodes. The radiant heating power and conductive heating power are adjusted according to the temperature field of the magnesium smelting lumps and the stable conductivity coefficient of the graphite electrodes. The continuous vacuum reduction and condensation module maintains a continuous vacuum environment during the processes of feeding magnesium smelting briquettes, vacuum reduction, magnesium vapor transfer, magnesium vapor condensation, metallic magnesium discharge, and reduction slag discharge. The waste heat cascade recovery module recovers the waste heat generated during the magnesium smelting process according to the waste heat temperature level, and distributes the recovered heat to the raw material calcination, magnesium smelting briquette preheating, magnesium smelting briquette drying and feed silo insulation processes. The carbon dioxide recovery module purifies and compresses the carbon dioxide-containing tail gas generated during the raw material calcination process, and causes the recovered carbon dioxide to undergo a mineralization reaction with the reducing slag. The intelligent production control module generates magnesium smelting production control data based on raw material status data, graphite electrode status data, synergistic heating status data, vacuum reduction status data, magnesium vapor condensation status data, waste heat recovery status data, and carbon dioxide recovery status data. Based on the magnesium smelting production control data, it adjusts the raw material supply, graphite electrode conductivity, radiative conductivity synergistic heating, continuous vacuum maintenance, magnesium vapor condensation, waste heat distribution, and carbon dioxide mineralization process.

2. The vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes according to claim 1, characterized in that: The raw material pretreatment and closed supply module includes a raw material calcination unit, a raw material crushing unit, a quantitative batching unit, a mixing and briquetting unit, a briquetting drying unit, a vacuum feeding preparation unit, and a double-gate closed feeding unit. The raw material calcination unit calcines magnesium-containing raw materials to generate calcined material, the raw material crushing unit processes the particle size of the calcined material, the quantitative batching unit measures the calcined material, reducing agent and mineralizing agent, and the mixing and briquetting unit mixes the calcined material, reducing agent and mineralizing agent and presses them to form magnesium briquetting material. The briquette drying unit receives the recovered heat output from the waste heat cascade recovery module to dry and preheat the magnesium briquette. The vacuum feeding preparation unit includes an atmospheric pressure storage silo, a vacuum transition silo, a feeding pusher, a first vacuum isolation valve, and a second vacuum isolation valve. The first vacuum isolation valve is located between the atmospheric pressure storage silo and the vacuum transition silo, and the second vacuum isolation valve is located between the vacuum transition silo and the vacuum reaction vessel. The dual-gate sealed feeding unit controls the first vacuum isolation valve and the second vacuum isolation valve to open and close alternately, and controls the feeding pusher to transport the magnesium smelting lumps to the vacuum reaction tank after the pressure in the vacuum transition chamber reaches the feeding equalization pressure.

3. The vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes according to claim 1, characterized in that: The graphite electrode stable conductivity module includes a graphite electrode densification treatment unit, a graphite electrode anti-oxidation treatment unit, a conductive clamping unit, an electrode can-penetrating sealing unit, an inert gas isolation unit, and a graphite electrode status judgment unit. The graphite electrode includes an external conductive connection section, a can-penetrating sealing section, and an internal heating section. The graphite electrode densification unit sequentially performs vacuum degassing, carbon impregnation, pressure infiltration, curing, and high-temperature carbonization treatments on the graphite electrode. The graphite electrode anti-oxidation treatment unit forms a silicon carbide anti-oxidation protective layer on the surface of the can-penetrating sealing section and the in-can heating section; The conductive clamping unit adjusts the clamping state of the external conductive connection section according to the conductive contact resistance and clamping pressure, and controls the temperature of the conductive contact area through the cooling channel; The electrode can-penetrating sealing unit includes an inner vacuum seal, an outer vacuum seal, and an isolation cavity located between the inner and outer vacuum seals. An inert gas isolation unit inputs inert protective gas into the isolation cavity. The graphite electrode state judgment unit generates a stable conductivity coefficient for the graphite electrode based on the current conductivity of the graphite electrode, the conductive contact resistance, the proportion of oxidation mass loss of the graphite electrode, and the axial temperature difference of the graphite electrode. It then adjusts the conductive clamping pressure and the input current of the graphite electrode based on the stable conductivity coefficient.

4. The vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes according to claim 3, characterized in that: The radiation-conductive synergistic heating module includes an external resistance radiation heating unit, an internal graphite electrode conductive heating unit, a material temperature field acquisition unit, a heat flow distribution analysis unit, and a heating power coordination unit. The external resistance radiation heating unit is arranged on the outer periphery of the vacuum reaction vessel and forms a preheating heating zone, a reduction heating zone and a heat preservation heating zone along the axial direction of the vacuum reaction vessel; The internal graphite electrode conductive heating unit controls the paired graphite electrodes to be energized, so that the heating section inside the tank generates Joule heat and transfers heat into the magnesium smelting material. The temperature field acquisition unit of the magnesia smelting material collects the outer layer temperature, center temperature, axial temperature and radial temperature of the magnesia smelting material. The heat flow distribution analysis unit generates synergistic heating state data based on the external radiation heat flow density, graphite electrode input power, outer wall temperature of the vacuum reaction vessel and the temperature distribution of the magnesia smelting material. The heating power coordination unit generates a heating coordination coefficient based on the coordinated heating state data, and adjusts the external resistance radiation heating power and the internal graphite electrode conductive heating power according to the center temperature of the magnesium smelting material, the outer layer temperature of the magnesium smelting material, the maximum internal temperature difference of the magnesium smelting material, and the stable conductivity coefficient of the graphite electrode.

5. The vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes according to claim 1, characterized in that: The continuous vacuum reduction and condensation module includes a special treatment unit for the vacuum reaction vessel, a staged vacuum pumping unit, a vacuum reduction control unit, a magnesium vapor directional transfer unit, a staged condensation unit, a closed magnesium discharge unit, and a closed slag discharge unit. The special treatment unit of the vacuum reactor performs full penetration welding on the tank body welds, performs vacuum degassing treatment on the inner wall of the vacuum reactor, and sets up a double-layer sealing structure and independent leak detection chamber at the feed port, slag discharge port, magnesium vapor port and electrode installation port. The staged vacuum pumping unit includes a pre-vacuum pump group, a medium vacuum pump group, a high vacuum pump group, a vacuum buffer tank, and a vacuum valve group, and controls the operation of the pre-vacuum pump group, the medium vacuum pump group, and the high vacuum pump group according to the magnesium smelting production stage. The magnesium vapor directional transfer unit is connected to the vacuum reaction vessel and the staged condensation unit via a high-temperature resistant vacuum pipeline equipped with heat-insulating heating components. The staged condensation unit includes a high-temperature flow guiding zone, a medium-temperature crystallization zone, and a low-temperature collection zone; The sealed magnesium discharge unit and the sealed slag discharge unit each include a vacuum transition chamber, an inner isolation valve, an outer isolation valve, and an independent vacuum port. The vacuum restoration control unit generates a vacuum continuity maintenance coefficient based on the vacuum reaction tank pressure deviation, system leakage rate, number of abnormal vacuum valve actions, and vacuum recovery time, and adjusts the vacuum pump group operation status and vacuum valve group opening and closing status according to the vacuum continuity maintenance coefficient.

6. The vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes according to claim 1, characterized in that: The waste heat recovery module includes a high-temperature waste heat recovery unit, a medium-temperature waste heat recovery unit, a low-temperature waste heat recovery unit, a heat medium circulation unit, a heat storage unit, and a heat distribution unit. The high-temperature waste heat recovery unit recovers waste heat from the high-temperature reduction slag and raw material calcination tail gas, and transports the high-temperature waste heat to the raw material calcination and magnesium smelting pellet preheating process. The medium-temperature waste heat recovery unit recovers waste heat from the outer wall of the vacuum reactor, the magnesium vapor condensation assembly and the high-temperature vacuum pipeline, and transports the medium-temperature waste heat to the magnesium smelting briquette drying and vacuum feeding preparation process. The low-temperature waste heat recovery unit recovers waste heat from vacuum pump exhaust, condensate cooling medium return water, and carbon dioxide compression equipment cooling medium, and delivers the low-temperature waste heat to the feed silo for insulation. The heat distribution unit generates waste heat distribution data based on waste heat temperature, waste heat flow rate, target temperature of each heat-using location, and production stage, and controls the heat medium flow rate of the high-temperature heat medium circuit, medium-temperature heat medium circuit, and low-temperature heat medium circuit based on the waste heat distribution data.

7. The vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes according to claim 1, characterized in that: The carbon dioxide recovery and utilization module includes a carbon dioxide gas collection unit, a dust removal and purification unit, a dehydration and compression unit, a carbon dioxide temporary storage unit, a reduction residue pretreatment unit, a mineralization and carbon fixation unit, and a carbon fixation product detection unit. The carbon dioxide-containing gas collection unit collects the carbon dioxide-containing tail gas output from the raw material calcination unit and generates carbon dioxide source data. The dust removal and purification unit and the dehydration and compression unit perform dust removal, purification, dehydration and compression treatment on the carbon dioxide-containing exhaust gas; The reducing slag pretreatment unit cools, crushes, screens, and adjusts the moisture content of the reducing slag to generate mineral raw materials; The mineralization and carbon fixation unit introduces carbon dioxide gas into the mineralization raw materials and adjusts the mineralization and carbon fixation process according to the mineralization reaction temperature, mineralization reaction pressure, carbon dioxide input flow rate, and mineralization reaction time. The carbon fixation product detection unit generates carbon dioxide mineralization fixation data based on the changes in mass, carbonate content, and carbon dioxide concentration before and after mineralization treatment, and generates a low-carbon resource utilization coefficient based on the carbon dioxide mineralization fixation data and waste heat recovery status data.

8. The vacuum internal heating magnesium smelting system based on stable electrical conductivity of graphite electrodes according to claim 1, characterized in that: The intelligent production control module includes a production data acquisition unit, a production status identification unit, a digital production model, a collaborative control unit, a fault diagnosis unit, a low-carbon evaluation unit, and a production traceability unit. The production data acquisition unit collects raw material status data, graphite electrode status data, synergistic heating status data, vacuum reduction status data, magnesium vapor condensation status data, waste heat recovery status data, and carbon dioxide recovery status data, and establishes a production data sequence according to production batch and acquisition time. The production status identification unit identifies the raw material preparation status, closed feeding status, heating status, vacuum reduction status, magnesium vapor condensation status, closed magnesium discharge status, closed slag discharge status, waste heat recovery status, and carbon dioxide mineralization status based on the production data sequence. The digital production model generates magnesium smelting production prediction data based on material balance, heat balance, electrical energy input, vacuum pressure changes, magnesium vapor generation rate, and carbon dioxide flow direction. The collaborative control unit adjusts the magnesium smelting briquette feed rate, graphite electrode input current, resistance furnace radiation heating power, vacuum pump group operating status, magnesium vapor condensation temperature, waste heat heat medium flow rate, and carbon dioxide mineralization input rate based on magnesium smelting production forecast data. The fault diagnosis unit generates abnormal data for magnesium smelting production based on the graphite electrode's stable conductivity coefficient, heating synergy coefficient, vacuum continuous holding coefficient, magnesium vapor generation rate, and condensation temperature. Based on the abnormal data, the corresponding production process is controlled to enter one of the following states: parameter adjustment state, heat preservation inspection state, or shutdown state. The low-carbon evaluation unit generates low-carbon evaluation results for production based on the unit magnesium metal energy consumption, waste heat reuse ratio, carbon dioxide recovery ratio, carbon dioxide mineralization and fixation ratio, and reduction slag resource utilization ratio. The production traceability unit generates magnesium smelting production traceability files based on the production data sequence and the low-carbon evaluation results.

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