SU1283253A1 - Method of steel melting - Google Patents

Abstract

The invention relates to ferrous metallurgy and can be used in the smelting of steel in hearth steelmaking units. The purpose of the invention is to increase the heating rate of the charge. At the surface of the scrap at a surface temperature of the charge of 600-700 ° C, waste from aluminum production is introduced followed by oxygen blowing. The heating rate of the charge increases as a result of the generation of additional heat during the oxidation of metal waste with gas-forming oxygen blowing. 2 silt, 2 tab. cl

Description

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The invention relates to ferrous metallurgy, in particular to steel melting methods in bottom steelmaking aggregates.

The purpose of the invention is to accelerate the heating of the solid charge.

The introduction of slag for the production of recycled aluminum before the charge is heated to 600 ° C does not accelerate the heating of the metal, which is due to the intradiffusional nature of the process of aluminum oxidation at low temperatures. After the batch is heated to 600 ° C, the oxidation of aluminum proceeds to an external diffusion mode, which ensures an intensive exothermic reaction of the aluminum oxidation reaction and, consequently, effective heating of the metal scrap 1, obtained in the laboratory 300-kilogram furnaces, depending on the temperature of scrap metal before the addition of slag from the production of recycled aluminum, are next, the temperature of the metal- The speed of the scrap before the addition of heat of the metal-slag from the production of lom, C / min secondary foot aluminum, ° C:

300 16.3 40015.2

50016,8

55017.1

60019.0

700 .19.2

The introduction of oxygen onto the surface of the solid heat carrier prior to the discharge of the cast iron makes it possible to fully utilize the heat used for heating the scrap metal. This prevents the loss of coolant from the primary slag and ensures the formation of an active highly basic slag before the iron is drained.

The indicated temperature range is optimal for the addition of aluminum production waste for the following 1 dm reasons. At the surface temperature of the scrap metal, under 600 C, there is no ignition of metallic aluminum in the oxygen stream and accelerated heating of the metal charge is not achieved, and when entering aluminum production waste and oxygen and heating the surface with scrap metal to temperatures exceeding 700 ° C, the preheating time increases.

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at

32332

heating, t, e, is the time from the beginning of the period of the heated metal to the addition of the additive, that С1шшает the average rate of metal charge temperature rise during the warm-up period.

Fig. 1 shows a graph of the change in the surface temperature of scrap metal when entering aluminum production wastes and oxygen at different scrap surface temperatures; figure 2 - the dependence of the average growth rate of the temperature of the metal charge on the temperature of its surface at the time

15 input waste aluminum production and oxygen.

In FIG. 1, curve I is obtained by inputting aluminum waste and oxygen into a 500-ton open-hearth furnace at.,

20 The temperature of the charge surface is 500 ° C, curve 2 is at 600 ° C, curve 3 is at 650 ° C, curve 4 is at 700 ° C, curve 5 is at 800 s. It follows from the above data that the addition of waste aluminum 25 after heating the scrap to 600 ° C leads to an increase in its heating rate, and the heating rate after the additive, characterized by the slope of the curve to the horizontal m, is not

30 depends on the surface temperature of the scrap at the time of addition.

The slag from the production of recycled aluminum used as a solid heat carrier has the following

OS composition, weight,%:

Alumina iron oxide silica silica sodium oxide 40 aluminum

50-70 5-10 3-8 3-4 8-30

The use of slag from the production of recycled aluminum as a solid heat carrier is due to the low silica content, which ensures the production of furnace slag with a high basicity, a high content of alumina, which provides high liquid mobility and desulphurisation of the furnace slag, and the rapid formation of a highly basic primary slag due to the presence of secondary slag aluminum oxide sodium, increasing the yield of steel by reducing the

losses with primary slag. The table presents the data characterizing the comparative effectiveness of the proposed and basic steelmaking methods.

31

The implementation of the proposed method allows to obtain an economic effect by reducing the consumption of cast iron in the amount of 0.39 rubles / ton.

Example When steelmaking in a 250-ton open-hearth furnace operating a scrap ore process, after filling the scrap metal and heating it to 630 ° C, 2.4 tons of secondary aluminum production slag was introduced into the subfurm zones and the purge was started with oxygen and an intensity of 1000 after 15 minutes after the start of purging, cast iron was produced.

pig iron was reduced in comparison with accepted by 5 kg / t (1.25 t). Duration — melting was reduced compared with averages by 10 minutes.

Claims (1)

Invention Formula The method of steel smelting, including the filling of the charge, the introduction of aluminum production waste and the blowing of oxygen, characterized in that, in order to accelerate the heating of the charge, the waste of aluminum production The total duration of the warm-up of the compound, gaseous oxygen, is supplied by the wafer for 50 min, the temperature of the metal-hard solid is charged when the memory reaches 1150 ° C at the end of the process. Consumption on the charge surface 600-700 ° G. Base 16.8 580 Proposed 19.4 575 fff th 30 40 50 Sff 70 tnposp pin FIG. 1.2 1100 0.24 90 0.8 1220 0.3 92 FIG. sixteen F t t Phage.2