SU1258844A1 - Method of treating metal in ladle - Google Patents

Description

I. 12588442

The invention relates to a secondary furnace. When the content of the combustible part in the waste coal is less than 20%

treatment of steel, more specifically to the processing of metal with an inert gas.

The purpose of the invention is to reduce heat loss and improve the quality of steel.

When coal wastes are introduced to the slag surface in the ladle, their mineral part is dissolved in the slag, while carbon interacts with iron oxides contained in the mineral component of the waste and slag, which leads to foaming of the latter and a significant increase in its heat-shielding properties. In addition, when the mineral part of the waste is dissolved in the slag, the content of silicon dioxide increases, while the gas permeability of the slag decreases significantly.

The temperature of the slag decreases, it becomes viscous and inactive due to the additional cost of heat associated with the flow of endotherms.

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it provides a sufficiently active foaming of the slag, which reduces the heat-isolating properties of the latter. In addition, at such a hot part, the absorption of heat as a result of the reactions of coal-thermal reduction of slag oxides is insufficient to significantly lower the temperature of the slag and thicken it, which leads to the transfer of phosphorus from slag to metal.

When the content of the combustible part in the waste is more than 40%, the processes of reducing phosphorus pentaoxide () slag to the main component of the combustible part — carbon — are noticeably developed, which degrades the quality of steel.

The method of treating steel with inert gas is carried out as follows.

After the metal and donkey are released from the steelmaking unit, the ladle is transferred to the stand, immersed in metal

20

chemical reactions of interaction of the pig iron- 25 lined form, through which

with iron oxides, as well as with heating and melting of waste. This leads to inhibition of the processes of transition of phosphorus from slag to metal and a significant decrease in the gas permeability of the spike.

Thus, the addition of coal waste to slag during the metal purging with an inert gas contributes to a significant reduction in heat losses from the surface of the liquid steel and a decrease in the concentrations of gases and phosphorus in it due to foaming and simultaneous thickening of the slag, as well as reducing its gas permeability.

When the coal waste is introduced in an amount of less than 0.2 kg / t, the slag is practically not thickened and does not foam, which leads to an increase in the phosphorus content in the metal during its refining and an increase in heat loss

The addition of coal waste in an amount of more than 2 kg / t causes the slag temperature to drop below the temperature of the onset of crystallization, which forms from the slag crust and is destroyed by the gas flow released from the metal, which leads to an increase in the gas saturation of the steel and metal mirrors.

it provides a sufficiently active foaming of the slag, which reduces the heat-isolating properties of the latter. In addition, at such a hot part, the absorption of heat as a result of the reactions of coal-thermal reduction of slag oxides is insufficient to significantly lower the temperature of the slag and thicken it, which leads to the transfer of phosphorus from slag to metal.

When the content of the combustible part in the waste is more than 40%, the processes of reduction of phosphorus pentaoxide () slag to the main component of the combustible part — carbon — are noticeably developed, which degrades the quality of steel.

The method of treating steel with inert gas is carried out as follows.

After the metal and donkey are released from the steelmaking unit, the ladle is transferred to the stand, immersed in metal

lined form through which

serves neutral gas. Purging can also be carried out during the bucket filling process. Simultaneously with the start of blowing on the slag surface

Coal wastes are deposited in the amount of 0.2-2.0 kg / t of steel, which leads to an increase in the heat-insulating and gas-protective properties of the slag, as a result of which the heat losses during blow-down are reduced and the quality of steel is improved.

Example. With the release of steel from a 300-ton open-hearth furnace into the ladle to a depth of about 4 m

lined lance, nitrogen gas of about 200 is supplied, and the metal and shpak are released into the ladle. At the same time, in the amount of 0.2-2.0 kg / ton of steel, waste coal from Donetsk coal (rock) with a particle size of 13–40 mm, formed in the depositors of the beneficiation plant, is introduced into the ladle. The purge is carried out for about 7 minutes, after which

the ladle is transferred to the casting and the steel is cast into 13 t ingots for a hot rolled sheet.

Treatment of the steel with a gaseous gas with a ladle with an additive on the slag from coal-rich waste makes it possible to reduce the temperature in the refining process from 25 ° C (according to known technology) to 7–10 ° C, reduce the degree of

31258844. 4

Refraction of steel from 28 to 0.5–4% and improvement in the quality of steel and reduction in the toughness of hot metal transfer to lower grades of steel sheets from 0.36 to 0.46–0.55 MJ / m of mechanical properties, respectively (see table) due to The table shows the effect of reducing the phosphorus content and gas pressure parameters on the heat loss of metal saturation. and the quality of steel when it is processed

The proposed method will allow to-in buckets with a capacity of 300 tons of gaseous

Begin to reduce fuel consumption with an additional agent, with additional waste, 8.8% for additional heating of the coal bath (application 1-10) and magnesnal communication with a decrease in heat loss of lime (Example 11) - according to

during secondary treatment, as well as in a well-known way.

Editor N.Egorova

Compiled by M. Pribavkin

Tehred L.Oleynik Proofreader V.But ha

Order 5088/26 Circulation 552Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk | nab. d. 4/5

. Production and printing company, Uzhgorod Project Project, 4

Claims (2)

1. METHOD FOR PROCESSING METAL IN A DUCK, including the release of metal and slag into a ladle, purging with inert gas and doping of slag with a heat insulating material, characterized in that, in order to reduce heat and heat losses and improve the quality of steel, as a heat insulating material planted coal enrichment waste in an amount of 0.2-2.0 kg / t of steel. 2. The method according to π, 1, with the fact that coal wastes contain 20-40% of combustible may * ses, the rest is ash .. S8 ω s SP 00 00 f