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Causes, Solutions And Preventive Measures For The Fire In The Cupola
Jan 02, 2019

The so-called cupola leaking furnace refers to accidental leakage of molten iron. The leaking fire in the furnace includes several fires at the bottom of the furnace and running through the bridge (including the slag runner running fire).

1. Analysis of the cause of the failure

(1) The quality of the bottom of the furnace or the quality of the bridge or the quality of the refractory material is poor. For example, the refractory material is poorly knotted, the thickness of the building is not enough, the knotting material is too dry, the bonding force or the bonding force is weak, and the knotting layer is not tight. The bottom of the furnace door is leaking and sanding.

(2) The moisture content of the knotting material is too high, and cracks are formed in the knotted layer during baking.

(3) The knotted layer is subjected to impact or vibration, resulting in depressions and cracks. For example, the firewood is broken, the bottom of the furnace is damaged, the bottom door of the furnace is loose during smelting, the crack occurs at the bottom of the furnace, and the bridge is damaged when passing through the bridge. .

(4) The distance between the bottom exhaust vent and the bottom of the furnace is too small and the angle is too large. When the slag opening is operated, the airflow blown into the furnace by the bottom exhaust vents the bottom of the furnace, so that the bottom of the furnace forms a pit and accumulates molten iron. The bottom of the furnace is quickly thinned, and the bottom of the furnace is cracked under the pressure of the column to cause a fire.

(5) The bridge built by the refractory bricks, the molten iron leaks in the gap between the refractory bricks to form a running fire; the bridge and the brick are not strict, when the middle section of the bridge or the outlet is blocked, the molten iron flows out from the gap, resulting in Run the fire.

(6) The smelting time is too long, and the refractory layer of the bottom of the furnace and the bridge is eroded to cause running fire.

(7) The tapping port and the residual iron port are blocked or accidentally opened.

2, the solution

(1) If it is found that the door bottom seam or the bridge has iron droplets, it can be blocked by the refractory mud without stopping the wind before the drip is formed into a stream.

(2) If the drip can not be blocked, the drip will gradually become a stream, and it needs to be stopped. After the wind is stopped, the molten iron will leak first. When the slag flows out of the crack, the crack is blocked with hard refractory mud. If the crack is long, it can be blocked by the two ends. After blocking, immediately block the crack on the pallet with a large piece of hard refractory mud, and support and tighten the refractory mud with the ram. The refractory mud on the pallet must be completely blocked by the leaking seam. If the crack is long, the double ejector can be used.

(3) If the plugging is invalid several times, the melting is finished by the furnace.

3. Preventive measures

(1) Configure the bottom of the furnace and the material for the bridge to be knotted in strict accordance with the process requirements. If the bottom of the furnace and the bridge are knotted with wet sand, the mass fraction of the refractory mud in the knot should be between 5% and 10%. After being uniformly mixed by the sand mixer, knotting is carried out. If it is required to open the furnace for a long time, the upper limit of the refractory mud content is taken, and if the time is short, the lower limit is taken. If the mud content is too high, the bottom of the furnace is sintered into a hard block, which may cause difficulty in the furnace. The moisture content of the binder is hand-kneaded into a dough. Preferably, the moisture should not be too high.

(2) The bottom of the furnace and the bridge must be layered and knotted to ensure uniformity of compaction. It must be ensured that the bottom of the furnace and the bottom of the bridge have a certain strength, and the wind is not melted by the action of molten iron, molten slag and slag opening. Ablation forms a pit. Pay special attention to strengthen the seam between the bottom of the furnace and the wall of the furnace, and the degree of tightness prevention at the corners. Appropriate rounding should be repaired between the bottom of the furnace and the lining, and appropriate measures can be taken to increase the bottom of the furnace. The slope of the direction.

(3) To ensure the thickness of the knotted layer of the bottom of the furnace and the bridge, the thickness of the bottom of the furnace and the bottom of the bridge should be determined according to the size of the furnace and the length of the furnace. The thickness of the cupola of the cupola of 3t/h and below is not less than 200mm, and the knotting thickness of 3t/h or more is not less than 300-400mm.

(4) When adding chopping wood during the charging process, firstly, a certain thickness of wood shavings should be placed on the bottom of the furnace, and then more than two layers of chopping wood should be placed to protect the bottom of the furnace. The remaining charge can be added from the feeding port.

(5) After the bottom of the furnace and the knotted layer of the bridge are dried in the shade, they are first baked with a simmer, and then baked with a large fire to prevent cracks in the baking.

(6) Before the bottom sand bed is built, fill the gap on the bottom door with refractory mud to avoid the sand leakage of the bottom door.


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