SU1177354A1 - Method of suppressing red fume in top filling ladle with molten metal - Google Patents

Abstract

1. A METHOD FOR SUPPRESSING THE FORMATION OF A BROUGH DAM WHEN FILLING A BUCKET WITH LIQUID METAL FROM THE TOP, including supplying neutral gas to the ladle prior to the start of discharge of metal into it, neutral gas is fed from the level above the upper edge of the bucket to the suction zone formed by a metal stream and limited to a cut by a bucket with a radius around the jet of 0.45-0.5 of the bucket radius of about 2. Along the method 1, I distinguish iys in that the neutral gas (A perekrshaet entire suction zone formed metal jet. 3. The method of Claim 1, 2j characterized in that the neutral gas is fed into an empty ladle in an amount of 1-3 volume bucket.

Description

S S The invention relates to ferrous metallurgy, in particular to methods for preventing emissions from overfusion of iron or steel. The purpose of the invention is to improve the efficiency of the dust suppression process to create safe working conditions and ensure the reliability of the neutral gas supply unit. The drawing shows the distribution of the flow rate of emissions at the shear bucket of the metal Stru, the pad at the bottom of the bucket carries the surrounding air layers behind it, forming a suction zone around the jet. The dimensions of the suction zone depend on the geometrical dimensions of the bucket and the radius of the jet. Ejected h: flow air reaches the point of impact of a jet of metal on the bottom of the bucket or on the surface of the liquid metal. Here, the recovered oxygen reacts with drops of liquid metal, which is the reason for the formation of brown smoke. Further, brown smoke is transported by a convective stream from the bucket. As can be seen from the drawing, at a distance of 0, A5 is 0.5 of the bucket radius (CL from the point of entry of the metal jet into the bucket cavity, the direction of the gas flow velocity coincides with the direction of the velocity W of the metal jet. away from the jet to the periphery of the bucket further than 0.45–0.5 of the bucket radius, the velocity of the emission flow is directed upwards. Consequently, the suction zone around the metal jet is limited to a distance of 0.45–0.5 of the bucket radius. Thus, the air enters the ladle through the suction zone, heating up with and throwing It is supplied through the periphery. The supply of neutral gas to the suction zone ensures that it circulates in the bucket volume, displaces the air and prevents the metal droplets from oxidizing. Neutral gas supply to an empty bucket in less than one volume of the bucket cannot provide complete displacement of air. multiple volume provides a steady reduction in dusting at the first moment of filling the bucket. Further pre-supply of gas does not improve the results of pressure suppression, therefore, leads to excessive gas consumption. Example. An experiment is performed to supply nitrogen gas to a ladle when casting iron from a mixer. Nitrogen is supplied through stationary nozzles located above the bucket and directed into the zone bounded on the cut with a radius of 0.4 of the bucket radius from the jet. Nitrogen consumption is 4000 nm / h. To obtain comparative data, parallel tests were carried out on casting iron without nitrogen supply. The effectiveness of the dust suppression process is assessed by reducing the concentration of brown smoke emitted into the atmosphere. It is established that the supply of nitrogen reduces the release of brown smoke more than 3 times. The main method of abatement is aspiration followed by gas cleaning. To completely clean the emissions, it requires a two-stage gas cleaning system consisting of NIIOGAS TsN-15 cyclones and an electrostatic precipitator, or a bag filter. TsN-15 cyclones almost completely trap coarse graphite spelles, however fine brown smoke dust is not trapped by them from. In order to trap fine dust, a second stage of cleaning is required - bag filters or electrostatic precipitators. The application of the proposed method for suppressing the formation of brown smoke makes it possible to refuse the construction of electrostatic filters or bag filters. The supply of neutral gas to the ejection zone prevents gas from being carried away by the emission stream before the gas reaches the point of impact of the jet on the bottom of the ladle or metal mirror, which makes it possible to effectively use neutral gas during the whole process of filling the ladle with liquid metal. This allows refusal to supply the rationed water to the bucket and increases the efficiency of the dust suppression process, since the supply of neutral water is more efficient than the supply of water. The failure to build water-bearing structures above the bucket and the spraying of water makes it possible to avoid possible accidents associated with the ingress of water into the liquid metal and to improve occupational safety.

The supply of neutral gas according to the proposed method allows refusing the lowering device and

to supply gas through the station

Blown nozzles located above the ladle and directed so that the gas gets into the area of the suction side formed by a stream of metal. This increases the reliability of the neutral gas supply unit.

-O.fO

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Claims (3)

LADDER WITH A LIQUID METAL FROM THE TOP, including the supply of neutral gas to an empty bucket before the metal is drained into it, characterized in that, in order to increase the efficiency of the process, create safe working conditions and ensure the reliability of the neutral gas supply unit, neutral gas is supplied from a level above the upper edge bucket into the suction zone formed by the metal stream and limited on the cut of the bucket with a radius around the stream of 0.45-0.5 of the radius of the bucket. 2. The method according to π.1, characterized in that the neutral gas covers the entire absorption zone formed by the metal stream. 3. The method according to claims 1 and 2, characterized in that the neutral gas g is fed into the empty bucket in an amount of 1-3 volumes of the bucket.