SU1715860A1 - Method of converter process control - Google Patents

Abstract

The invention relates to ferrous metallurgy, and more specifically to the control and management of smelting in a converter. The aim of the invention is to improve the accuracy and reliability of controlling the temperature of the metal. The goal is achieved in the method of controlling the temperature of a metal in a converter, including continuous measurement of the composition of carbon-containing gases, calculating the purge time and temperature of the metal; . Slag dilution is carried out by raising the oxygen tuyere and / or by introducing fluorspar in the amount of 0.5-1.0 kg / ton of steel. 1 hp f-ly, 1 tab. Yo

Description

The invention relates to the field of ferrous metallurgy, and more specifically to the control and management of steel smelting in a converter.

The purpose of the invention is to improve the accuracy and reliability of controlling the temperature of the metal.

The essence of the invention is to; that the composition of the carbon-containing gases is measured continuously, the purge time and the metal temperature are calculated, a reference carbonate-containing material additive is introduced into the converter as it passes through the purge, and the liquor is liquefied by an oxygen lance lift and / or input of fluorspar in the amount of 0.5-1.0 kg / t of steel.

After 90-95% of the purging time, in most cases the slag in the converter is in a heterogeneous (minimized) state. This is due to the fact that

blowing in connection with a decrease in the carbon content in the metal decreases the number of ejection bubbles {CO} that foam the slag, which causes it to collapse.

Entering a carbonate-containing material, such as limestone, into the converter in a converter for dense heterogeneous slag leads to a deterioration in the conditions of their interaction with each other, which in turn leads to instability of the results of temperature calculation. This is due to the fact that the condition of the slag in the converter has a significant effect on the decomposition of lime.

In order to improve the absorption and decomposition of the standard limestone additive before it is introduced into the converter, slag are preliminary diluted. This operation is performed by simultaneously raising the oxygen coupling and entering

00

sc o

spar. In this case, the slag dilution is achieved by increasing its FeO content and increasing the surfactant F ions in the slag.

Additive to the converter for thick heterogeneous slag of fluorspar in the amount of less than 0.5 kg / ton of steel does not provide the necessary dilution of slag. However, in fluorspar waters of more than 1.0 kg / ton of steel, although it provides the necessary liquefaction, it can lead to excessive slag foaming, emissions from the converter and possible stopping of the blowout to wet the slag. Such overrun of fluorspar worsens the technical and economic indicators of the process.

The best results on slag dilution are achieved when fluorspar is introduced into the converter in the amount of 0.5-1.0 kg / ton of steel, at which no significant metal outliers and emissions are observed.

PRI me R. Under the conditions of a converter shop in converters with a capacity of 400 tons, 10 experimental heats were carried out using the proposed method and 10 heats according to the known method. As a reference additive, lime is used to a mass of 800 kg. The time of decomposition of limestone is determined by the content of {CO} in the exhaust gases, which is monitored using a FTIAN-3 gas analyzer. Average melting time 20 min. The actual metal temperature is monitored with a measuring probe. All calculations are made using a special program on the CM-1 computer. As a calculation formula use the expression:

T

mrassch /

a x e: mde Tmrassch. —the design temperature of the metal, ° C, Fractional limestone decomposition time, s;

a, b are empirical coefficients that are determined empirically using regression and dispersion

analysis, and comprise the following values:,, 0012.

The reference additive was introduced after 19 minutes of purging (20.0x0, min).

60-40 s before the introduction of the reference additive, slag is liquefied by raising the oxygen tuyere by 300-400 mm relative to the established working level and introducing fluorspar weighing 200-300 kg into the converter.

The results of experimental and comparative heats are given in the table.

The actual temperatures of the metal Tf are obtained by using a measuring probe.

An analysis of the results presented in the table shows that the accuracy of calculating the temperature of the metal by the proposed method is higher than that known, whose mean square deviations are respectively ± 13.2 versus ± 15.0 ° С.

Improving the accuracy of controlling the temperature of the metal will improve the technical and economic performance of the process, reduce by 30% the proportion of heats requiring additional blowdown at a given temperature, increase the productivity of converters.

Claims (2)

1. A method of controlling the temperature of a metal in a converter, including continuous measurement of the composition of carbon-containing gases, calculating the time of purging and temperature of the metal, entering into the converter during the purging of the reference additive carbonate-containing material, characterized in that , before the start of the introduction of the reference additive, slag is diluted. 2. Method according p. 1, characterized in that the slag is diluted by raising the oxygen tuyere and / or introducing fluorspar in the amount of 0.5-1.0 kg / ton of steel. Table continuation