Most domestic iron and steel enterprises generally use open ladle to hold molten iron. The ladle is placed on the ladle car and transported from the blast furnace to the steelmaking operation area by diesel locomotive or car. At present, the blast furnace in domestic iron and steel enterprises is far away from the steelmaking operation area. This section of the road is open-air working condition, especially the waiting time for receiving iron under the blast furnace and mixing iron in the steelmaking area, which is 3-5 hours. During the uncovered transportation of the molten iron ladle, plus the opening of the molten iron ladle, the molten iron is directly in contact with the air. The temperature difference between the molten iron and the molten iron ladle and the air is large, and the continuous heat exchange takes place, and a large amount of heat is emitted. Especially, the heat dissipation area of the empty ladle after mixing the molten iron is large, It increases energy consumption and affects the life of iron ladle lining, increases production costs, and the safety of hot metal for transportation is also poor, which is worse in rainy and snowy weather

During the actual temperature measurement on site, the temperature drop rate of the inner wall of the empty ladle is about 10 ℃/min, 7 ℃/min, 3.5 ℃/min and 2 ℃/min when the temperature is 1100/1000/900/800 ℃ and 700 ℃, respectively, while the temperature drop rate is basically maintained at about 0.9 ℃/min when the temperature is lower than 700 ℃

The temperature drop of molten iron is 0.9-1.5 ° C/min, including the waiting time for receiving molten iron under the blast furnace and mixing iron in the steelmaking area, which is about 290min, and the shortest time is 140min. It can be seen that the temperature drop of high temperature iron ladle is the largest when it is empty. The temperature drop of molten iron is mainly caused by the heat transfer of molten iron to the refractory of iron ladle, so the heat storage and insulation of refractory of iron ladle is very important

If the temperature drop of molten iron is too large, it will not only cause heat waste, but also affect the subsequent pretreatment and steelmaking process, and seriously affect the production scheduling and ladle life due to the occurrence of condensation. Therefore, the problem of molten iron cooling at the interface between iron and steel has attracted the attention of technical personnel of enterprises and scientific research departments

Calculate the average temperature data of hot metal ladle (with cover) and hot metal ladle (without cover) under heavy ladle transportation, The field test data are as follows:

tapping temperature ℃

temperature before iron blending ℃

temperature difference between tapping and iron blending ℃

Not stamped

1455.0

1347.0

108

1447.2

1336.9

110.3

1435.8

1327.4

108.4

1446.2

1329.1

117.1

1451.3

1336.7

114.6

Average

1449.1

1337.4

111.6

Stamp

1457.8

1366.6

91.2

1443.0

1354.2

88.8

1438.3

1347.4

90.9

1452.5

1356.8

95.7

1446.7

1354.2

92.5

Average

1447.6

1355.8

91.8

Comparison between capping and uncovered

19.7

The capping device of the hot metal car can not only significantly reduce the heat loss of the hot metal during transportation and waiting, but also effectively reduce the emission of pollutants such as smoke and dust into the atmosphere, increase the environmental protection index, and achieve the purpose of energy conservation and environmental protection. Its installation and maintenance are convenient, and its operation is simple and suitable for promotion and use

Molten iron is the main raw material for steelmaking, generally accounting for 70% to 100% of the loading. The temperature of molten iron has a great impact on steelmaking. The temperature of molten iron is a sign of how much physical heat is brought into the converter. According to the converter steelmaking process, the heat of converter smelting basically comes from the physical heat and chemical heat of molten iron, and the physical heat of molten iron accounts for about 50% of the furnace heat income. When the chemical heat is certain, the physical heat of molten iron is the key factor to determine whether the smelting can proceed smoothly. The low temperature of molten iron causes large blow loss, high consumption of iron and steel materials, insecure quality of molten steel, decreased furnace life and other consequences, and affects the element oxidation process and the temperature rise rate of the molten pool, which is not conducive to slag formation and removal of impurities, and is prone to splash

The molten iron is transported from the blast furnace to the converter in the steelmaking plant. The tapping temperature of the blast furnace is 1350-1450 ° C. It needs to go through a series of processes such as tapping, transportation, pretreatment, pouring, empty tank return and waiting. Each process and the state of the molten iron tank have an impact on the temperature drop of the molten iron. Iron and steel enterprises are generally characterized by more blast furnaces, more users of molten iron, and more tank cars for transporting molten iron. Moreover, it is difficult to locate and track the molten iron cars moving around the plant. These reasons increase the difficulty of controlling the molten iron transportation process and reducing the temperature drop of molten iron

The temperature of molten iron is the key factor to determine whether smelting can proceed smoothly, especially in the key period of energy saving and consumption reduction. If the temperature of molten iron fluctuates greatly, it will lead to high blowing loss of molten steel, high consumption of steel materials, high cost, insecure quality of molten steel, decreased furnace life, and endanger safety production and other serious consequences. Therefore, it is of great significance to keep the temperature of molten iron in the converter stable

In recent years, China's rapid economic development has caused immeasurable damage to the environment while enjoying the fruits of economic development. With the continuous improvement of national environmental protection requirements and energy conservation policies, the upgrading of pollution emission standards, and the continuous strengthening of supervision and law enforcement, the awareness of iron and steel enterprises on environmental protection and energy conservation is increasing. Therefore, it is necessary to take effective measures to reduce the heat loss of molten iron during transportation and waiting and the emission of pollutants such as smoke and dust into the atmosphere

At present, a large amount of dust and smoke generated in the tank during iron receiving and operation are directly discharged into the air by the domestic hot metal car capping device, which pollutes the surrounding environment, and the temperature of hot metal decreases rapidly, resulting in a large amount of energy loss and increasing the cost of steelmaking. With the continuous improvement of national environmental protection requirements and policies, iron and steel enterprises are increasingly aware of environmental protection and energy conservation. The traditional uncovered mixed-iron car can no longer meet the needs of users