SU1560560A1 - Method of steel melting in open-hearth furnace - Google Patents

Abstract

The invention relates to ferrous metallurgy, and in particular to methods for steelmaking in open-hearth furnaces using aluminum-containing wastes. The purpose of the invention is to increase the explosion safety of the process and prevent an uncontrolled increase in the decarburization rate. The goal is achieved by the fact that aluminum-containing slag is introduced into the bath after reversing the torch to the bath site remote from the furnace head end 1 / 8-1 / 7 the bath length and 1 / 5-1 / 4 the bath width from the back and front walls , and consumption of 8–16 kg / ton of steel per hour. When implementing the method, a reduction in the amount of emissions and explosions is achieved. 1 il.

Description

The invention relates to ferrous metallurgy, in particular, to methods for smelting steel in open-hearth furnaces using aluminum-containing wastes.

The purpose of the invention is to increase the explosion safety of the process and prevent the uncontrolled increase in the decarburization rate.

The drawing shows the scheme of implementation of the method.

The slag is introduced into the area of the bath surface in which the gradual dissolution of the aluminum-containing slag in the furnace slag takes place. At the same time, the rate of carbon oxidation does not decrease, but the mixing of the metal is deteriorated, the slag does not overheat, which creates conditions for eliminating the negative consequences of the introduction of aluminum-containing waste into the bath.

When aluminum-containing slag is introduced into the bath section, which is less than 178 bath lengths from the fiery window, the material enters the stagnant zone and does not have time to dissolve in the slag during the period between valve overshoots. This leads to the fact that after transfer, the exhaust gases directly in front of the fiery window react with metal-aluminum,

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About About SL

which is oxidized with carbon dioxide to form CO by reaction.

2 (A1A, etNZ {C0g} - (A120E) + + 3 {CO

Carbon monoxide entering the vertical channel creates an explosion hazard in the lower / furnace structure.

When aluminum-containing slag is introduced into the section of the bath surface located at a distance of more than 1/7 of the bath length from the fiery window, it is 10605604

a sufficiently effective reduction of the viscosity of the furnace slag is achieved, the productivity of the furnace does not increase.

When the input rate of aluminum-containing slag is more than 16 kg / t-h, it is impossible to avoid overheating of the furnace slag and the upper metal layers, which leads to emissions and an explosion in the lower structure of the furnace.

Entering the aluminum-containing slag directly after the valve roll-over is due to the fact that in this case

there is a rapid dispersed slag J5 tea during the time of interaction of the material

over the bath surface, metallic aluminum actively reacts with excess oxygen due to highly developed interface, the degree of post-combustion of CO to COi decreases, which increases the likelihood of an explosion. In addition, the rapid uptake of aluminum-containing slag causes an increase in the temperature of the furnace slag and the adjacent metal layers, which, after complete oxidation, leads to a violent reaction between the superheated low-oxidation metal and the bulk of the oxidized metal. Origin t

emissions of metal and slag. Nekontroliru-zd A1 12-, 68; Si02 6-, CaO 6, e NaCl +

+ KC1 4; impurities (Mp.O, MnO, FeO, 4.). In the experimental heats, the slag was injected using a filling machine, which allowed to adjust the intensity of the input materials.

The increase in the rate of oxidation of carbon leads to a sharp increase in the second ingress of carbon monoxide into the vertical channel, which is an additional source of explosion hazard.

When aluminum-containing slag is introduced to a section remote from the front and front walls of the furnace for a distance of less than 1/5 of the width of the vanna, the material enters the stagnant zone and does not dissolve during the period between the rolls, which leads to an increased risk of explosion.

An analysis of the results of experimental melts shows that the application of the proposed method provides a significant decrease in the content of carbon monoxide in the exhaust gases.

This is due to the oxidation of aluminum with carbon dioxide. When introducing aluminum-containing 45 ° technology of the prototype method, for slag at the bath site, which is characterized by an arbitrary wavelength more than 1/4 the width of the bath from the back and front walls, the additive dissolves rapidly

cage of aluminum-containing slag, the carbon monoxide content in the exhaust gases reaches 3.2%, which leads

1 furnace slag, leading to an increase in the content of CQ to an uncontrolled increase in the rate of CO in the exhaust gases and the overheating of the upper metal layers. Explosiveness increases, emissions from the furnace occur due to an uncontrolled increase in the carbon oxidation rate.

With an input rate of aluminum-containing mothers more than 8 kg / t-h not

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carbon oxidation, accompanied by emissions in 20% of cases, as well as to claps (explosions) in the lower structure of the furnace in 17% of cases.

Claims (1)

Invention Formula The method of steelmaking in the open-hearth furnace, including the additive is not 0 from the bath to the next transfer, the maximum is therefore eliminated the possibility of reducing carbon dioxide to oxide directly at the entrance to the vertical channel. Example. Steel Grade 70 was smelted in a 600-ton open-hearth furnace using a scrap ore process, with an intensive purging of the bath with oxygen (flow rate 4000). In the course of finishing, immediately after the valves were re-injected, aluminum-containing slag was introduced into the bath. Fractions 2-12 mm of the following chemical composition,%: A1 12-, 68; Si02 6-, CaO 6, e NaCl + + KC1 4; impurities (Mp.O, MnO, FeO, 4.). In the experimental heats, slag was introduced using a filling machine, which allowed the intensity of the input materials to be adjusted. Material consumption in all cases was 5 kg / t steel. The results of the implementation of the experimental water baths are given in the table. An analysis of the results of experimental melts shows that the application of the proposed method provides a significant reduction in the content of carbon monoxide in the exhaust gases. ° technology of the prototype method, for which arbitrary characterization is characteristic ° technology of the prototype method, for which arbitrary characterization is characteristic cage of aluminum-containing slag, the carbon monoxide content in the exhaust gases reaches 3.2%, which leads carbon oxidation, accompanied by emissions in 20% of cases, as well as to claps (explosions) in the lower structure of the furnace in 17% of cases. Invention Formula The method of steelmaking in the open-hearth furnace, including the additive is not furnace slag during the period of finishing smelting waste from the production of recycled aluminum, characterized in that, in order to increase the explosion safety of the process and prevent an uncontrolled increase in the decarburization rate, the aluminum  Carbon monoxide content in waste gases during the period of interaction of aluminum-containing slag in the bath,%. The share of melts with emissions of metal and slag from the furnace,%. Dol heats, which were observed claps (explosions) in the lower structure of the furnace. 05G, P6 SCHIY NPPK RVODYA GP I LSNU YOG ON placing a torch on a section of the nlppa remote from the end of the furnace head is 1/8 ... 1/7 the length of the bath and on l / i, .. / the width of the bath from the back and front walls, at a rate of 8 ... 16 kg / tons of steel in 1 hour Torch  jar l