1. The utility model provides a sub-vacuum electric smelting magnesium oxide is smelted and carbon dioxide catches recovery system, removes dolly, furnace body, smelting furnace section of thick bamboo, feeding device, electrode elevating system, sack cleaner, transformer and automatic control system including smelting, its characterized in that: also comprises a carbon dioxide recovery system connected with the bag-type dust remover,

the furnace body is a cylinder structure furnace body with an opening at the lower part, the bottom of the cylinder structure furnace body is arranged on the ground of a horizontal foundation, an operation platform is arranged at the upper part of the cylinder structure furnace body, the cylinder structure furnace body is provided with a partition plate A, a partition plate B and a partition plate C, electrode mounting holes are concentrically formed in the operation platform, the top of the cylinder structure furnace body, the partition plate C, the partition plate B and the partition plate A from top to bottom, automatic feeding holes are further arranged on two sides of the electrode mounting holes in the partition plate A, the partition plate A is arranged at the lower part of the cylinder structure furnace body, so that the lower part of the cylinder structure furnace body forms a smelting chamber, an access door is arranged on the side wall of the smelting chamber, the smelting furnace cylinder is arranged on a smelting moving trolley and enters and exits the smelting chamber through the access door, the partition plate B and the partition plate C are arranged at the middle part of the cylinder structure furnace body at intervals, and the cloth bag dust remover is arranged at the upper part of the cylinder structure furnace body, a smoke outlet is arranged on the side wall of the lower part of the furnace body with the cylinder structure, and a smoke inlet is arranged on the bag-type dust collector;

the electrode lifting mechanism comprises a graphite electrode, an electrode guide sleeve connected with the graphite electrode through a screw thread and a hydraulic telescopic mechanism connected with the upper part of the electrode guide sleeve, wherein the upper part of the hydraulic telescopic mechanism extends out of the furnace body with a cylindrical structure, the electrode guide sleeve and the graphite electrode respectively penetrate through an operation platform, the upper part of the furnace body with the cylindrical structure, a partition plate C, a partition plate B and a partition plate A from top to bottom and are inserted into the smelting furnace cylinder, a sealing device is arranged among the electrode guide sleeve, the partition plate C and the partition plate B, a sealed cylinder is formed below the middle part of the furnace body with the cylindrical structure and serves as a vacuum chamber, meanwhile, the partition plate C and the partition plate B also serve as limiting supports of the electrode guide sleeve, and the hydraulic telescopic mechanism is connected with a transformer and a control system through cables;

the feeding device is arranged at the lower part of the operating platform and comprises a feeding hopper, a feeding pipe and a star-shaped discharge valve which are arranged at the outer side of the upper part of the furnace body with a cylinder structure, the star-shaped discharge valve is arranged at the lower part of the feeding hopper, one end of the feeding pipe is communicated with the lower part of the feeding hopper through the star-shaped discharge valve, the other end of the feeding pipe passes through an automatic feeding hole on the partition plate A and is communicated with the smelting furnace cylinder, an ash discharge port is arranged at the lower part of the dust remover, and the ash discharge port is connected with the feeding hopper of the feeding device through an ash discharge pipe and a ball valve;

carbon dioxide recovery system include flue gas recovery pipe I, II vacuum pumps of flue gas recovery pipe, exhaust gas stack and carbon dioxide recovery pipe, I one end of flue gas recovery pipe be connected with the exhaust port of opening on the lateral wall of tubular structure furnace body lower part, the other end is linked together with the mouth of cigarette 1 that advances on the dust remover, flue gas recovery pipe II be Z style of calligraphy flue gas recovery pipe, the inlet end of vacuum pump and the air inlet intercommunication of Z style of calligraphy flue gas recovery pipe, the exhaust end of vacuum pump is linked together with exhaust gas stack and carbon dioxide recovery pipe respectively through the three-way valve.

2. The system according to claim 1, wherein the number of the electrode mounting holes is three, and the number of the automatic charging holes is four.

3. The sub-vacuum electric smelting magnesia smelting and carbon dioxide capturing and recycling system according to claim 2, wherein the number of the charging hoppers of the charging device is two, each charging hopper is provided with two discharging openings, the number of the feeding pipes and the number of the star-shaped discharging valves are four, one end of each feeding pipe is connected with the star-shaped discharging valve, the other end of each feeding pipe penetrates through the automatic charging hole and is inserted into the smelting furnace cylinder, and the number of the electrode lifting mechanisms is three.

4. The system for smelting sub-vacuum fused magnesia and capturing and recovering carbon dioxide according to claim 1, wherein the partition plate C, the partition plate B and the partition plate A are made of nonmagnetic white steel plates, the sealing device comprises a bakelite insulating plate, a heat-resistant sealing rubber ring, a square sealing ring and a sealing filler, one end of the bakelite insulating plate is fixedly connected with the partition plate C and the partition plate B through bolts, the other end of the bakelite insulating plate is abutted against the outer side of the electrode guide sleeve, the heat-resistant sealing rubber ring and the square sealing ring are arranged at the lower part of the partition plate C, and the sealing filler is arranged between the partition plate C and the partition plate B, so that a cylindrical furnace body below the partition plate C and the partition plate B forms a sub-vacuum state.

5. The sub-vacuum electrofusion magnesium oxide smelting and carbon dioxide capture and recovery system according to claim 1, wherein the vacuum pump is a roots vacuum pump.

6. A sub-vacuum electric smelting magnesium oxide smelting and carbon dioxide capturing and recovering process is characterized by comprising the following steps:

s1) feeding

Putting magnesite concentrate powder into two charging hoppers, and then sealing the charging openings of the charging hoppers;

s2) preparing furnace

Pushing the smelting furnace barrel into a smelting chamber of a furnace body with a barrel structure, paving a padding layer and a broken electrode for conducting, descending the graphite electrode to enable the graphite electrode to be conducted with the broken electrode, and then closing an access door;

s3) starting-up smelting and carbon dioxide recovery

S3.1) starting a vacuum pump, and simultaneously conducting a three-way valve with a waste gas exhaust pipe, wherein gas in the furnace body with the cylindrical structure forms a vacuum pumping state under the action of negative pressure;

s3.2) when the vacuum degree in the furnace body with the cylindrical structure reaches-0.05 mpa, feeding and power supplying are started, the temperature between the graphite electrode tips is increased, the waste gas exhaust pipe is closed by the three-way valve, and the carbon dioxide recovery pipe is opened;

and S3.3) carrying out smelting operation according to the production process of the fused magnesia, wherein in the operation process, when the temperature in the furnace reaches 2800 ℃, magnesite concentrate powder starts to decompose and melt and discharge carbon dioxide gas, at the moment, the carbon dioxide gas is sucked into a bag-type dust remover under the action of negative pressure, and the purified carbon dioxide gas is sent to a carbon dioxide pressurizing and liquefying workshop through a vacuum pump and a carbon dioxide recovery pipe for recycling.

Background

With the rapid development of the iron and steel smelting industry in China and China in recent years, the demand for high-quality refractory materials is increased, and the consumption of electric smelting-grade magnesium oxide is greatly increased, but the magnesite resources of high-quality raw materials in nature are reduced continuously.

With the reduction of high-quality magnesite resources, a new magnesite beneficiation process in the industry is developed, the raw materials for beneficiation are low-grade magnesite which cannot be utilized before, high-quality magnesite concentrate is obtained through a flotation process, the content of magnesium oxide can reach over 47.4%, but in the traditional electric smelting process of magnesium, the magnesite concentrate powder can be used for smelting only through pelletizing, the cost of pelletizing is generally 200 yuan/ton, and the amount of balls used for each ton of electric smelting magnesium oxide is 2.5: 1.

The traditional electric smelting magnesia smelting process is to use special-grade magnesite raw ore to be crushed and screened by a crusher to obtain magnesite lump ore with the granularity of 20mm-80mm, the magnesite lump ore is put into a furnace to be electrified and heated, carbon dioxide generated in the smelting process is naturally discharged, if the discharge is not smooth, splashing can be caused, and scalding danger is caused to field workers.

Disclosure of Invention

The invention aims to provide a system and a process for smelting sub-vacuum electric melting magnesium oxide and capturing and recovering carbon dioxide, which can reduce cost, ensure production safety and effectively recover carbon dioxide.

The invention discloses a sub-vacuum electric smelting magnesium oxide smelting and carbon dioxide capturing and recovering system, which comprises a smelting moving trolley, a furnace body, a smelting furnace cylinder, a feeding device, an electrode lifting mechanism, a bag-type dust collector, a transformer and an automatic control system, and is characterized in that: also comprises a carbon dioxide recovery system connected with the bag-type dust remover,

the furnace body is a cylinder structure furnace body with an opening at the lower part, the bottom of the cylinder structure furnace body is arranged on the ground of a horizontal foundation, an operation platform is arranged at the upper part of the cylinder structure furnace body, the cylinder structure furnace body is provided with a partition plate A, a partition plate B and a partition plate C, electrode mounting holes are concentrically formed in the operation platform, the top of the cylinder structure furnace body, the partition plate C, the partition plate B and the partition plate A from top to bottom, automatic feeding holes are further arranged on two sides of the electrode mounting holes in the partition plate A, the partition plate A is arranged at the lower part of the cylinder structure furnace body, so that the lower part of the cylinder structure furnace body forms a smelting chamber, an access door is arranged on the side wall of the smelting chamber, the smelting furnace cylinder is arranged on a smelting moving trolley and enters and exits the smelting chamber through the access door, the partition plate B and the partition plate C are arranged at the middle part of the cylinder structure furnace body at intervals, and the cloth bag dust remover is arranged at the upper part of the cylinder structure furnace body, a smoke outlet is arranged on the side wall of the lower part of the furnace body with the cylinder structure, and a smoke inlet is arranged on the bag-type dust collector;

the electrode lifting mechanism comprises a graphite electrode, an electrode guide sleeve connected with the graphite electrode through a screw thread and a hydraulic telescopic mechanism connected with the upper part of the electrode guide sleeve, wherein the upper part of the hydraulic telescopic mechanism extends out of the furnace body with a cylindrical structure, the electrode guide sleeve and the graphite electrode respectively penetrate through an operation platform, the upper part of the furnace body with the cylindrical structure, a partition plate C, a partition plate B and a partition plate A from top to bottom and are inserted into the smelting furnace cylinder, a sealing device is arranged among the electrode guide sleeve, the partition plate C and the partition plate B, a sealed cylinder is formed below the middle part of the furnace body with the cylindrical structure and serves as a vacuum chamber, meanwhile, the partition plate C and the partition plate B also serve as limiting supports of the electrode guide sleeve, and the hydraulic telescopic mechanism is connected with a transformer and a control system through cables;

the feeding device is arranged at the lower part of the operating platform and comprises a feeding hopper, a feeding pipe and a star-shaped discharge valve which are arranged at the outer side of the upper part of the furnace body with a cylinder structure, the star-shaped discharge valve is arranged at the lower part of the feeding hopper, one end of the feeding pipe is communicated with the lower part of the feeding hopper through the star-shaped discharge valve, the other end of the feeding pipe passes through an automatic feeding hole on the partition plate A and is communicated with the smelting furnace cylinder, an ash discharge port is arranged at the lower part of the dust remover, and the ash discharge port is connected with the feeding hopper of the feeding device through an ash discharge pipe and a ball valve;

carbon dioxide recovery system include flue gas recovery pipe I, II vacuum pumps of flue gas recovery pipe, exhaust gas stack and carbon dioxide recovery pipe, I one end of flue gas recovery pipe be connected with the exhaust port of opening on the lateral wall of tubular structure furnace body lower part, the other end is linked together with the mouth of cigarette 1 that advances on the dust remover, flue gas recovery pipe II be Z style of calligraphy flue gas recovery pipe, the inlet end of vacuum pump and the air inlet intercommunication of Z style of calligraphy flue gas recovery pipe, the exhaust end of vacuum pump is linked together with exhaust gas stack and carbon dioxide recovery pipe respectively through the three-way valve.

Preferably, the number of the electrode mounting holes is three, and the number of the automatic feeding holes is four.

Preferably, the charging device is provided with two charging hoppers, each charging hopper is provided with two feed openings, the number of the feeding pipes and the number of the star-shaped discharge valves are four, one end of each feeding pipe is connected with the star-shaped discharge valve, the other end of each feeding pipe penetrates through the automatic charging hole to be inserted into the smelting furnace barrel, and the number of the electrode lifting mechanisms is three.

Preferably, the partition plate C, the partition plate B and the partition plate A are made of nonmagnetic white steel plates, the sealing device comprises a bakelite insulating plate, a heat-resistant sealing rubber ring, a square sealing ring and a sealing filler, one end of the bakelite insulating plate is fixedly connected with the partition plate C and the partition plate B through bolts, the other end of the bakelite insulating plate is abutted to the outer side of the electrode guide sleeve, the heat-resistant sealing rubber ring and the square sealing ring are arranged at the lower part of the partition plate C, and the sealing filler is arranged between the partition plate C and the partition plate B, so that a cylindrical furnace body below the partition plate C and the partition plate B forms a sub-vacuum state.

Preferably, the vacuum pump is a roots vacuum pump.

The invention relates to a sub-vacuum electric smelting magnesium oxide smelting and carbon dioxide capturing and recovering process, which is characterized by comprising the following steps:

s1) feeding

Putting magnesite concentrate powder into two charging hoppers, and then sealing the charging openings of the charging hoppers;

s2) preparing furnace

Pushing the smelting furnace barrel into a smelting chamber of a furnace body with a barrel structure, paving a padding layer and a broken electrode for conducting, descending the graphite electrode to enable the graphite electrode to be conducted with the broken electrode, and then closing an access door;

s3) starting-up smelting and carbon dioxide recovery

S3.1) starting a vacuum pump, and simultaneously conducting a three-way valve with a waste gas exhaust pipe, wherein gas in the furnace body with the cylindrical structure forms a vacuum pumping state under the action of negative pressure;

s3.2) when the vacuum degree in the furnace body with the cylindrical structure reaches-0.05 mpa, feeding and power supplying are started, the temperature between the graphite electrode tips is increased, the waste gas exhaust pipe is closed by the three-way valve, and the carbon dioxide recovery pipe is opened;

and S3.3) carrying out smelting operation according to the production process of the fused magnesia, wherein in the operation process, when the temperature in the furnace reaches 2800 ℃, magnesite concentrate powder starts to decompose and melt and discharge carbon dioxide gas, at the moment, the carbon dioxide gas is sucked into a bag-type dust remover under the action of negative pressure, and the purified carbon dioxide gas is sent to a carbon dioxide pressurizing and liquefying workshop through a vacuum pump and a carbon dioxide recovery pipe for recycling.

The invention has the advantages that:

because the magnesium oxide is smelted under the sub-vacuum condition, in the smelting process, carbon dioxide gas in magnesium oxide liquid in the furnace can be forcibly sucked out, so that splashing can not be generated in the smelting process, the production safety is ensured, negative pressure enables the magnesium oxide crystal not to have bubbles, and the product density is greatly improved; in addition, as the raw materials use magnesite concentrate, the production cost is saved without ball pressing, 500 yuan/ton can be saved when one ton of electric smelting magnesia is produced, the content of magnesia in the raw materials is more than 47.4 percent, and the content of harmful slag is less than 1 percent, so that the content of magnesia in the electric smelting magnesia crystal of the whole furnace is more than 98 percent.

In addition, because the smelting is full sub-vacuum smelting and 90% of carbon dioxide gas is recovered, the smelting process plays a positive promoting role in carbon recovery, carbon neutralization and clean production.

Drawings

FIG. 1 is a schematic structural diagram of a sub-vacuum electric smelting and carbon dioxide capture and recovery system for magnesium oxide.

Fig. 2 is a side view of fig. 1.

Fig. 3 is a cross-sectional view taken along line D-D of fig. 1.

Fig. 4 is an enlarged view of a portion I of fig. 1.

Detailed Description

The invention will be further explained with reference to the drawings.

As shown in fig. 1-4, the system for smelting sub-vacuum fused magnesia and capturing and recovering carbon dioxide comprises a smelting moving trolley 1, a furnace body, a smelting furnace cylinder 2, a feeding device, an electrode lifting mechanism, a bag-type dust collector 14, a transformer 11 and an automatic control system, and is characterized in that: also comprises a carbon dioxide recovery system connected with the bag-type dust collector 14,

the furnace body is a cylinder structure furnace body 3 with an opening at the lower part, the bottom of the cylinder structure furnace body 3 is arranged on the horizontal foundation ground, an operation platform 4 is arranged at the upper part of the cylinder structure furnace body 3, the cylinder structure furnace body is provided with a partition plate A, a partition plate B and a partition plate C, electrode mounting holes are concentrically arranged on the operation platform 4, the top of the cylinder structure furnace body 3, the partition plate C, the partition plate B and the partition plate A from top to bottom, automatic feeding holes are also arranged at two sides of the electrode mounting holes on the partition plate A, the partition plate A is arranged at the lower part of the cylinder structure furnace body 3, so that the lower part of the cylinder structure furnace body 3 forms a smelting chamber 7, an access door 6 is arranged on the side wall of the smelting chamber 7, the smelting furnace cylinder 2 is arranged on a smelting moving trolley and enters and exits the smelting chamber through the access door 6, the partition plate B and the partition plate C are arranged at the middle part of the cylinder structure furnace body 3 at intervals, the bag-type dust collector 14 is arranged at the upper part of the tubular structure furnace body 3, a smoke outlet 131 is arranged on the side wall of the lower part of the tubular structure furnace body 3, and a smoke inlet 132 is arranged on the bag-type dust collector 14;

the electrode lifting mechanism comprises a graphite electrode 8, an electrode guide sleeve 9 connected with the graphite electrode 8 in a threaded manner and a hydraulic telescopic mechanism 12 connected with the upper part of the electrode guide sleeve 9, wherein the upper part of the hydraulic telescopic mechanism 12 extends out of the cylindrical structure furnace body 3, the electrode guide sleeve 9 and the graphite electrode 8 respectively penetrate through an operating platform 4, the upper part of the cylindrical structure furnace body 3, a partition plate C, a partition plate B and a partition plate A from top to bottom and are inserted into the smelting furnace barrel 2, a sealing device is arranged between the electrode guide sleeve 9 and the partition plates C and B, so that a closed barrel is formed below the middle part of the cylindrical structure furnace body 3 and serves as a vacuum chamber, meanwhile, the partition plates C and B also serve as limiting supports of the electrode guide sleeve 9, and the hydraulic telescopic mechanism 12 is connected with a transformer 11 and a control system through a cable 10;

the feeding device is arranged at the lower part of the operating platform and comprises a feeding hopper 18, a feeding pipe 16 and a star-shaped discharge valve 17 which are arranged at the outer side of the upper part of the furnace body 3 with a cylinder structure, the star-shaped discharge valve 17 is arranged at the lower part of the feeding hopper 18, one end of the feeding pipe 16 is communicated with the lower part of the feeding hopper 18 through the star-shaped discharge valve 17, the other end of the feeding pipe passes through an automatic feeding hole on the partition plate A and is communicated with the smelting furnace cylinder 2, an ash discharging opening is arranged at the lower part of the bag-type dust collector, and the ash discharging opening is connected with the feeding hopper 18 of the feeding device through an ash discharging pipe 19 and a ball valve 20;

carbon dioxide recovery system include flue gas recovery pipe I13, flue gas recovery pipe II 21 vacuum pump 22, exhaust gas exhaust pipe 25 and carbon dioxide recovery pipe 24, flue gas recovery pipe I13 one end be connected with the exhaust port 131 of opening on the 3 lower part lateral walls of tubular structure furnace body, the other end is linked together with the mouth 132 of advancing on the sack cleaner, flue gas recovery pipe II 21 be Z style of calligraphy flue gas recovery pipe, vacuum pump 22 the inlet end and the air inlet intercommunication of Z style of calligraphy flue gas recovery pipe, vacuum pump 22's exhaust end is linked together with exhaust gas exhaust pipe 25 and carbon dioxide recovery pipe 24 respectively through three-way valve 23.

The number of the electrode mounting holes is three, and the number of the automatic feeding holes is four.

Preferably, the number of the charging hoppers 18 of the charging device is two, each charging hopper 18 is provided with two feed openings, the number of the feeding pipes 16 and the number of the star-shaped discharge valves 17 are four, one end of each feeding pipe 16 is connected with the star-shaped discharge valve 17, the other end of each feeding pipe passes through an automatic charging hole and is inserted into the smelting furnace barrel 2, and the number of the electrode lifting mechanisms is also three, as shown in fig. 3.

The partition plate C, the partition plate B and the partition plate A are made of nonmagnetic white steel plates, the sealing device comprises a bakelite insulating plate 51, a heat-resistant sealing rubber ring 52, a square sealing ring 53 and a sealing filler 54, one end of the bakelite insulating plate 51 is fixedly connected with the partition plate C and the partition plate B through bolts, the other end of the bakelite insulating plate is abutted to the outer side of the electrode guide sleeve 9, so that insulation is realized between a conductive copper pipe in the electrode guide sleeve and the partition plate C and the partition plate B, the heat-resistant sealing rubber ring 52 and the square sealing ring 53 are arranged at the lower part of the partition plate C, and the sealing filler is arranged between the partition plate C and the partition plate B, so that the cylindrical furnace body 3 below the partition plate C and the partition plate B is in a sub-vacuum state, as shown in figure 4.

The invention relates to a sub-vacuum electric smelting magnesium oxide smelting and carbon dioxide capturing and recovering process, which is characterized by comprising the following steps:

s1) feeding

The magnesite concentrate powder is loaded into two charging hoppers 18, and then the charging openings of the charging hoppers are sealed;

s2) preparing furnace

Pushing the smelting furnace barrel 2 into a smelting chamber 7 of a furnace body 3 with a barrel structure, paving a padding layer 27 and a broken electrode 26 for conducting electricity, descending the graphite electrode 8 to enable the graphite electrode 8 to be communicated with the broken electrode 26, and then closing the access door 6;

s3) starting-up smelting and carbon dioxide recovery

S3.1) starting the vacuum pump 22, and simultaneously conducting the three-way valve with the waste gas exhaust pipe, wherein gas in the furnace body with the cylindrical structure forms a vacuum pumping state under the action of negative pressure;

s3.2) when the vacuum degree in the furnace body with the cylindrical structure reaches-0.05 mpa, feeding and power supplying are started, the temperature between the graphite electrode tips is increased, the waste gas exhaust pipe is closed by the three-way valve, and the carbon dioxide recovery pipe is opened;

and S3.3) carrying out smelting operation according to the production process of the fused magnesia, wherein in the operation process, when the temperature in the furnace reaches 2800 ℃, magnesite concentrate powder starts to decompose and melt and discharge carbon dioxide gas, at the moment, the carbon dioxide gas is sucked into the bag-type dust remover 14 under the action of negative pressure, and the purified carbon dioxide gas is sent into a carbon dioxide pressurizing and liquefying workshop through a vacuum pump 22 and a carbon dioxide recovery pipe 24 for recycling.

The ash discharge port of the bag-type dust collector is respectively connected with two charging hoppers 18 by adopting ball valves, the vacuum pump is a roots vacuum pump, purified carbon dioxide gas is sent to a carbon dioxide pressurizing and liquefying workshop by the roots vacuum pump, the roots vacuum pump is also a sub-vacuum main fan, the air quantity is five times of the quantity of the carbon dioxide gas produced in an hour, and the vacuum pressure is-0.05 mpa.

The smelting automatic control system adopts the existing automatic control system, the vacuum pump, the ball valve, the star-shaped ash discharge valve and the transformer of the smelting automatic control system are all connected with the automatic control system, and meanwhile, the electrode lifting mechanism automatically lifts the graphite electrode along with the rise of the smelting liquid level in the furnace.

Because the whole production process is carried out in a closed state, the process is sub-vacuum smelting, gas in magnesium oxide liquid in the furnace can be sucked out forcibly, the magnesium oxide liquid can not splash during smelting, the production safety is ensured, negative pressure ensures that no bubbles exist in magnesium oxide crystals, the product density is greatly improved, the production cost is saved because magnesite concentrate is used without ball pressing, 500 yuan/ton per ton of fused magnesium oxide can be saved when one ton of fused magnesium oxide is produced, the magnesium oxide contained in the raw materials is more than 47.4 percent, and the content of harmful slag is less than 1 percent, so the fused magnesium oxide crystals in the whole furnace contain more than 98 percent of magnesium oxide, and in addition, because the process is full sub-vacuum smelting, 90 percent of carbon dioxide gas is recovered, the smelting process plays a positive role in carbon recovery and carbon neutralization, and clean production.