A low temperature slag discharge process

Abstract

The invention discloses a low-temperature slag discharge process, and relates to the technical field of blast furnace smelting. The process comprises the following steps: S1: during blast furnace production, the daily control standard T1-T2 of blast furnace slag temperature is determined according to process requirements, and the units of T1 and T2 are both ℃; S2: when the temperature of molten iron discharged from the iron mouth is lower than T1, the blast furnace operation first takes measures to increase the furnace temperature; S3: when the temperature of molten iron discharged from the iron mouth is lower than the lower limit of T1 by 50℃, it is preliminarily judged that the furnace slag temperature is insufficient, and the slag is discharged according to the abnormal temperature of the furnace slag. The present invention has realized the effective discharge of low-temperature slag of blast furnace in the application of this technology, and by adding a combustion-supporting agent, the cold slag can be heated online quickly, and the phenomenon of adhesion of the iron mouth channel can be basically eliminated. The discharged slag is heated online, which greatly reduces the phenomenon of rapid condensation and adhesion of the slag in the slag groove, and proposes a combustion-supporting powder made on site, most of which uses blast furnace by-products, has low production cost, is convenient to obtain materials, and has good heating effect.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace smelting, and in particular to a low-temperature slag discharge process. Background Art

[0002] The slag generated by blast furnace smelting is regularly discharged from the blast furnace hearth through the iron mouth together with molten iron. In the blast furnace hearth area, slag and molten iron are in a mixed state. In order for the slag to be discharged smoothly from the hearth area, it is necessary to ensure that the hearth slag has a high temperature. When the hearth slag temperature is low, the fluidity of the slag drops sharply, and it is difficult to discharge from the iron mouth. Even if the slag can be discharged smoothly from the iron mouth, after flowing from the iron mouth to the main ditch, the slag is rapidly cooled by contact with the atmosphere, causing the slag temperature to drop rapidly in the main ditch. After the slag is separated in the main ditch, the slag flows into the slag ditch, causing the slag ditch to condense rapidly, and the slag ditch is not discharged smoothly. It is necessary to manually organize the dredging of the slag ditch, which is labor-intensive and has high operation risks.

[0003] When the blast furnace slag temperature is low, if the cold slag is not discharged from the furnace in time to make room for the fuel to fall, it is very easy to cause the furnace to freeze, which is a major process accident of the blast furnace. The furnace slag temperature is generally measured by the temperature of the molten iron discharged from the iron mouth. The standards for blast furnaces of different capacities are different, generally 2000-4000m 3 In a blast furnace with a capacity of 1000MW, the temperature of molten iron drops to 1450℃, the heat in the furnace is seriously insufficient, and the slag is easily condensed when it flows out, which is a low temperature state. During the production of the blast furnace, various problems such as improper operation process, water leakage in the cooling system, fluctuations in raw material quality, etc. can easily lead to low slag iron temperature in the furnace, which is an unavoidable phenomenon.

[0004] Under existing technical conditions, when the furnace slag iron temperature is low, coke is usually added to the upper part of the blast furnace to supplement heat, and the furnace slag iron temperature is gradually increased after the coke reaction; or the slag iron temperature is increased by reducing the wind to relieve the heat consumption in the furnace and increasing the heat storage in the furnace. After the furnace slag iron temperature rises, the slag iron is discharged smoothly. Both heat supplementation and heat storage take a long time. Generally, adding coke requires a smelting cycle, and reducing the wind and storing heat takes at least 2 hours or even longer.

[0005] Under existing technical conditions, when the temperature of the furnace slag is low, the iron outlet is usually opened and blocked multiple times for discharge. This operation method leads to significant loss of materials such as drill rods in front of the furnace and a large increase in consumption. When the low-temperature slag flows to the slag ditch and condenses, the slag ditch quickly slags and lumps, and cleaning requires a lot of physical labor and has high safety risks.

[0006] Therefore, a new solution to the above problems needs to be proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a low-temperature slag discharge process. By applying this technology, the effective discharge of low-temperature slag iron from the blast furnace is realized. By adding a combustion-supporting agent, the cold slag iron can be quickly heated online, and the phenomenon of iron mouth channel adhesion can be basically eliminated. The discharged slag is heated online, which greatly reduces the phenomenon of rapid condensation and adhesion of the slag in the slag groove, so as to solve the technical problems raised in the background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a low-temperature slag discharge process, comprising at least the following steps:

[0009] S1: During the blast furnace production, the daily control standard T1-T2 of blast furnace slag temperature is determined according to the process requirements, and the units of T1 and T2 are both ℃;

[0010] S2: When the temperature of the molten iron discharged from the taphole is lower than T1, the blast furnace operator first takes measures to increase the furnace temperature;

[0011] S3: When the temperature of molten iron discharged from the taphole is lower than the lower limit of T1 by 50°C, it is preliminarily judged that the slag temperature in the furnace is insufficient, and the slag discharge is organized according to the abnormal slag temperature in the furnace.

[0012] Preferably, the process in S1 needs to determine at least the blast furnace capacity, the required molten iron temperature range, the molten iron temperature control standard, the local altitude, the air pressure and the type of molten iron to be smelted.

[0013] Preferably, the measures for increasing the furnace temperature in S2 at least include the following steps:

[0014] Discharge the low-temperature slag iron from the furnace as quickly as possible;

[0015] For every 10℃ decrease in molten iron temperature compared to T1, increase the blast furnace fuel ratio by 3-5kg / t for supplementary heat. The greater the temperature decrease, the higher the supplementary fuel ratio should be.

[0016] While increasing fuel consumption, the blast furnace began to reduce airflow to increase the heat storage capacity of the furnace. The air volume was reduced by 10°C when the molten iron temperature was reduced by 100m 3 / min.

[0017] Preferably, the S3 at least further comprises the following steps:

[0018] First, select the iron mouth of the blast furnace where no slag iron has been discharged, and use an opening machine to drill a hole at the iron mouth channel. When a red dot appears at the iron mouth channel, stop drilling. After the iron mouth is opened, exit the opening machine.

[0019] Two groups of iron-mouth oxygen-burning metal pipes are connected, one group of the iron-mouth oxygen-burning metal pipes is connected to medium-pressure oxygen, and the other group of the iron-mouth oxygen-burning metal pipes is connected to compressed air. Before connecting the compressed air, the iron-mouth oxygen-burning metal pipes need to be poured with a mixture of aluminum powder and bag dust removal ash into the group of metal oxygen-burning pipes;

[0020] Put two sets of iron mouth oxygen burning metal pipes into the pre-drilled iron mouth channel, first slowly open the docking oxygen valve, oxygen is passed into the metal oxygen burning pipes, the red spot or high temperature inside the iron mouth channel ignites the metal oxygen burning pipes under the action of oxygen, press the metal oxygen burning pipes into the iron mouth to burn the iron mouth;

[0021] When the iron mouth is burned through, slag and iron flow out from the iron mouth channel, the oxygen is turned off, and the metal oxygen burning pipe connected to the oxygen is withdrawn;

[0022] Open the compressed air purge to blow the aluminum powder and bag dust powder mixture in another set of metal tubes into the iron mouth channel and the furnace area. The blown powder will react violently with the hot slag inside the furnace, further heating the slag discharged from the iron mouth.

[0023] The metal pipe connected to the compressed air is continuously extended into the iron mouth passage to continuously heat the slag iron inside the iron mouth passage;

[0024] The compressed air flow rate is controlled so that the distance between the slag iron blown out of the iron mouth and the main slag iron groove outside the iron mouth is within 1-3 meters;

[0025] As the metal tube is extended, it continues to melt. When the remaining metal tube reaches the main ditch skimmer position, the compressed air is stopped, the tube is reconnected, and the mixed powder is reloaded to continuously heat the cold slag discharged from the iron mouth area and quickly heat the outflowing slag.

[0026] Preferably, the drill bit of the opening machine has a diameter of 60-65 mm.

[0027] Preferably, the iron mouth oxygen-fired metal pipes are butt-jointed via large and small heads, the diameter of the iron mouth oxygen-fired metal pipes is at least 12 mm-24 mm, and the lengths of the two groups of the iron mouth oxygen-fired metal pipes are both 30 m-50 m.

[0028] Preferably, the aluminum powder and bag dust ash mixture is mixed in a ratio of 1 part aluminum powder to 1 part bag dust ash, the bag dust ash is at room temperature, and the bag dust ash includes at least 30% iron powder, 30% coke powder and 40% other ash.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention realizes the effective discharge of low-temperature slag iron in blast furnace by applying this technology. By adding combustion-supporting agent, the cold slag iron can be heated online quickly, and the phenomenon of iron mouth channel sticking can be basically eliminated. The discharged slag is heated online, which greatly reduces the phenomenon of slag quickly condensing and sticking in the slag groove.

[0031] 2. The present invention proposes on-site produced combustion-supporting powder, most of which uses blast furnace by-products, has low production cost, is easy to obtain, and has good heating effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] A low-temperature slag discharge process comprises at least the following steps:

[0036] S1: During the blast furnace production, the daily control standard T1-T2 of blast furnace slag temperature is determined according to the process requirements. The units of T1 and T2 are both ℃;

[0037] S2: When the temperature of the molten iron discharged from the taphole is lower than T1, the blast furnace operator first takes measures to increase the furnace temperature;

[0038] S3: When the temperature of molten iron discharged from the taphole is lower than the lower limit of T1 by 50°C, it is preliminarily judged that the slag temperature in the furnace is insufficient, and the slag discharge is organized according to the abnormal slag temperature in the furnace.

[0039] The process in S1 needs to determine at least the blast furnace capacity, the required molten iron temperature range, the molten iron temperature control standard, the local altitude, the air pressure and the type of molten iron to be smelted. It should be noted that the conditions included in different embodiments may also be more or less.

[0040] Generally 1000m 3 Blast furnace, T1-T2 temperature is 1450-1480℃, 3000m 3 For blast furnaces with a capacity of or above, the T1-T2 temperature is at least 1500-1530℃.

[0041] The measures for increasing the furnace temperature in S2 at least include the following steps:

[0042] Because it takes a certain amount of time for heat supplement and wind reduction heat storage to alleviate the heat loss of furnace slag iron, it is necessary to discharge the low-temperature slag iron from the furnace as soon as possible;

[0043] When the molten iron temperature decreases by 10℃ compared to T1, the blast furnace fuel ratio is increased by 3-5kg / t for supplementary heat. The greater the temperature decrease, the higher the supplementary fuel ratio is. Supplementary fuel requires at least one smelting cycle of the blast furnace to reflect the supplementary heat effect.

[0044] While increasing fuel consumption, the blast furnace began to reduce airflow to increase the heat storage capacity of the furnace. The air volume was reduced by 10°C when the molten iron temperature was reduced by 100m 3 / min.

[0045] S3 also includes at least the following steps:

[0046] First, select the iron mouth of the blast furnace where the slag iron has not been discharged, and use the opening machine to drill a hole at the iron mouth channel. When a red dot appears in the iron mouth channel, stop drilling. At this point, if the iron mouth is drilled directly with a drill bit, the cold slag iron will flow out with the drill bit, which will soon cause the iron mouth channel to stick together, making it difficult for the slag iron to flow out of the iron mouth channel, resulting in failure of slag iron discharge. After the iron mouth is opened, exit the opening machine;

[0047] Two sets of iron-mouth oxygen-burning metal pipes are connected, one set of which is connected to medium-pressure oxygen, and the other set of which is connected to compressed air. Before connecting the compressed air, the iron-mouth oxygen-burning metal pipes need to be filled with a mixture of aluminum powder and bag dust removal ash;

[0048] Put two sets of iron mouth oxygen burning metal pipes into the pre-drilled iron mouth channel, first slowly open the docking oxygen valve, oxygen is passed into the metal oxygen burning pipes, the red spot or high temperature inside the iron mouth channel ignites the metal oxygen burning pipes under the action of oxygen, press the metal oxygen burning pipes into the iron mouth to burn the iron mouth;

[0049] When the iron mouth is burned through, slag and iron flow out from the iron mouth channel, the oxygen is turned off, and the metal oxygen burning pipe connected to the oxygen is withdrawn;

[0050] Open the compressed air purge to blow the aluminum powder and bag dust powder mixture in another set of metal tubes into the iron mouth channel and the furnace area. The blown powder will react violently with the hot slag inside the furnace, further heating the slag discharged from the iron mouth.

[0051] The metal pipe connected to the compressed air is continuously extended into the iron mouth passage to continuously heat the slag iron inside the iron mouth passage;

[0052] The compressed air flow rate is controlled so that the distance between the slag iron blown out of the iron mouth and the main slag iron groove outside the iron mouth is within 1-3 meters;

[0053] As the metal tube is extended, it continues to melt. When the remaining metal tube reaches the main ditch skimmer position, the compressed air is stopped, the tube is reconnected, and the mixed powder is reloaded to continuously heat the cold slag discharged from the iron mouth area and quickly heat the outflowing slag.

[0054] The drill bit of the opening machine has a diameter of 60-65 mm, which may be of different sizes in different embodiments.

[0055] Whether a red dot appears in the iron mouth channel can be determined by whether sparks are blown out, or by the predicted iron mouth depth. In the embodiment, it is when the iron mouth depth is 4 / 5 or when the distance from the predicted iron mouth point position is 200-300mm.

[0056] The iron mouth oxygen-fired metal pipes are butt-jointed through large and small joints. The diameter of the iron mouth oxygen-fired metal pipes is at least 12mm-24mm. The lengths of the two groups of iron mouth oxygen-fired metal pipes are both 30m-50m. Different sizes are used in different embodiments.

[0057] The mixture of aluminum powder and bag dust ash is mixed in the ratio of 1 part of aluminum powder to 1 part of bag dust ash. The bag dust ash is at room temperature and includes at least 30% of iron powder, 30% of coke powder and 40% of other ash.

[0058] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A low-temperature slag discharge process, characterized in that: At least the following steps are included: S1: During the blast furnace production, the daily control standard T1-T2 of blast furnace slag temperature is determined according to the process requirements, and the units of T1 and T2 are both ℃; The process in S1 needs to determine at least the blast furnace capacity, the required molten iron temperature range, the molten iron temperature control standard, the local altitude, air pressure and the type of molten iron to be smelted; S2: When the temperature of the molten iron discharged from the taphole is lower than T1, the blast furnace operator first takes measures to increase the furnace temperature; The measures for increasing the furnace temperature in S2 at least include the following steps: Discharge the low-temperature slag iron from the furnace as quickly as possible; For every 10℃ decrease in molten iron temperature compared to T1, increase the blast furnace fuel ratio by 3-5kg / t for supplementary heat. The greater the temperature decrease, the higher the supplementary fuel ratio should be. While increasing fuel consumption, the blast furnace began to reduce airflow to improve the heat storage capacity of the furnace. The air volume was reduced by 100m³ / min according to the molten iron temperature being reduced by 10℃. S3: When the temperature of the molten iron discharged from the taphole is lower than the lower limit of T1 by 50°C, it is preliminarily judged that the furnace slag temperature is insufficient, and the slag discharge is organized according to the abnormal furnace slag temperature; The S3 at least further comprises the following steps: First, select the iron mouth of the blast furnace where no slag iron has been discharged, and use an opening machine to drill a hole at the iron mouth channel. When a red dot appears at the iron mouth channel, stop drilling. After the iron mouth is opened, exit the opening machine. Two groups of iron-mouth oxygen-burning metal tubes are connected, one group of the iron-mouth oxygen-burning metal tubes is connected to medium-pressure oxygen, and the other group of the iron-mouth oxygen-burning metal tubes is connected to compressed air. Before connecting the compressed air, the iron-mouth oxygen-burning metal tubes need to be poured with a mixture of aluminum powder and bag dust removal ash into the group of iron-mouth oxygen-burning metal tubes before connecting the compressed air; Put two sets of iron mouth oxygen burning metal pipes into the pre-drilled iron mouth channel, first slowly open the docking oxygen valve, oxygen is passed into the iron mouth oxygen burning metal pipes, the red spot or high temperature inside the iron mouth channel ignites the iron mouth oxygen burning metal pipes under the action of oxygen, press the iron mouth oxygen burning metal pipes to burn the iron mouth inside the iron mouth; When the iron mouth is burned through, slag and iron flow out from the iron mouth channel, the oxygen is turned off, and the iron mouth oxygen burning metal pipe connected to the oxygen is withdrawn; Open the compressed air purge to blow the aluminum powder and bag dust removal ash powder mixture in another set of iron mouth oxygen burning metal tubes into the iron mouth channel and the furnace area. The blown powder will react violently with the hot slag iron inside the furnace, further heating the slag iron discharged from the iron mouth; The iron mouth oxygen burning metal pipe connected to the compressed air is continuously extended into the iron mouth passage to continuously heat the slag iron inside the iron mouth passage; The compressed air flow rate is controlled so that the distance between the slag iron blown out of the iron mouth and the main groove of the external slag iron can be within the range of 1-3 meters; As the iron mouth oxygen-burning metal tube is extended, the iron mouth oxygen-burning metal tube is continuously melted. When the remaining iron mouth oxygen-burning metal tube reaches the position of the main ditch slag skimmer, the compressed air is stopped, the tube is re-connected, and the mixed powder is re-loaded to continuously heat the cold slag discharged from the iron mouth area and quickly heat the outflowing slag.

2. A low-temperature slag discharge process according to claim 1, characterized in that: The drill bit of the opening machine has a diameter of 60-65 mm.

3. A low-temperature slag discharge process according to claim 1, characterized in that: The iron-mouth oxygen-fired metal pipes are butt-jointed via large and small joints, the diameter of the iron-mouth oxygen-fired metal pipes is at least 12 mm to 24 mm, and the lengths of the two groups of the iron-mouth oxygen-fired metal pipes are both 30 m to 50 m.

4. A low-temperature slag discharge process according to claim 1, characterized in that: The aluminum powder and bag dust ash mixture is mixed in a ratio of 1 part aluminum powder to 1 part bag dust ash, the bag dust ash is at room temperature, and the bag dust ash includes at least 30% iron powder, 30% coke powder and 40% other ash.

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