RU2321643C2 - Steel melting method in electric-arc steel melting furnace - Google Patents

Abstract

FIELD: ferrous metallurgy, namely processes for steel melting in electric-arc steel melting furnaces.

SUBSTANCE: method comprises steps of loading metal scrap into furnace; pouring cast iron; melting; frothing slag due to oxygen blowing through and due to blowing-in carbon-containing material at oxidizing period; discharging melt material into ladle. Dust of blast furnace production is used as carbon-containing material at intensity of blowing-in 10 - 100 kg/min and at flow rate 2.5 -20 kg per ton of steel or dust of gas scrubbing of electric steel melting production at intensity of blowing-in 15 - 150 kg/min and flow rate 3.8 - 30 kg per ton of steel.

EFFECT: improved frothing properties of furnace slag, lowered number of emergency interruptions due to decreased irradiation of electric arc refining acting upon water-cooled members of furnace, shortened period of melting process, effective recovery of waste production materials.

Description

The invention relates to ferrous metallurgy, in particular to methods of steel smelting in electric arc furnaces.

Known as a prototype is a method of steelmaking in an electric arc furnace, including filling scrap metal in a furnace, casting iron, melting, foaming slag by blowing oxygen and blowing carbon-containing material, the oxidation period, the release of melting in the ladle [1].

Significant disadvantages of this method of steelmaking in electric arc furnaces are:

- significant downtime due to burnout of water-cooled furnace elements and refractory masonry due to reduced foaming properties of the slag and high arc radiation due to poor shielding of the arcs by slag;

- an increase in the duration of melting due to inefficient input of power of the electric furnace unit due to the lack of effective shielding of arcs;

- increasing the cost of electric steel in connection with the introduction into the furnace of coke powder for foaming slag.

The desired technical results of the invention are:

- increase the foaming properties of furnace slag and reduce emergency stops due to a decrease in radiation during electric arc remelting on water-cooled furnace elements;

- increased productivity of the electric furnace unit in connection with a reduction in the duration of the smelting

- efficient disposal of industrial waste.

To this end, a method is proposed for steelmaking in an electric arc furnace, including filling scrap metal in a furnace, pouring molten iron, melting, foaming slag by blowing with oxygen and blowing carbon-containing material into the oxidizing period, melting into a ladle, characterized in that carbon-containing material is used :

1) blast furnace top furnace dust at an injection rate of 10-100 kg / min and at a flow rate of 2.5-20 kg / t of steel or

2) gas treatment dust from electric steelmaking at an injection rate of 15-150 kg / min and at a flow rate of 3.8-30 kg / t of steel.

The claimed limits are selected experimentally. At an injection rate of less than 10 kg / min and a blast furnace dust consumption of less than 2.5 kg / t of steel or at an intensity of injection of dust from a gas treatment of electric steel production less than 15 kg / min and at a consumption of 3.8 kg / t of steel, it was not possible to obtain foamed slag in due to the insufficient content of carbon-containing component in the materials.

With an intensity of injection of blast furnace top furnace dust exceeding 100 kg / min with a flow rate of more than 20 kg / t of steel or with an intensity of blowing dust of gas cleaning of electric furnace production of more than 150 kg / min with a flow rate of more than 30 kg / t of steel, the material is not fully used, because In contact with the slag due to the “cooling” of the slag surface with a large amount of material, the FeO + С = СО reaction proceeds more slowly and the slag foaming is insignificant, in addition, there is intense clogging of the gas exhaust furnace of tract.

The inventive method of steelmaking was implemented in the smelting of steel in electric arc furnaces DSP-100I7. Smelting was carried out according to the following scheme. After the scrap metal was melted and molten iron was poured, the metal was purged with gaseous oxygen and powder materials were blown (blast furnace dust or gas treatment dust from electric steelmaking). In the experimental batches used blast furnace flue dust having the following chemical composition: 35-42% FeO, 19-27% C, 4,0-5,0% CaO, 7,2-8,1% SiO _2, 2,8-2 9% Al ₂ O ₃ , 0.3-0.4 MnO, 0.03-006% P ₂ O ₅ ; ESPC gas purification dust of the following composition: 43-47% FeO, 7.9-19.0% С, 20.4-23.5% CaO, 12.0-13.8% SiO ₂ , 0.6-0.8 % Al ₂ O ₃ , 0.10-0.25% P ₂ O ₅ , 0.3-0.6 MnO. Blowing was carried out using three BSE wall tuyere-injectors with blast furnace dust blasting intensity from 5 to 120 kg / min with a flow rate of 2.0-25 kg / t of steel; dust gas treatment electric steelmaking at an injection rate of 5-170 kg / min with a flow rate of 3.0-35 kg / t of steel.

After bringing the temperature and carbon content to the required values, the steel was discharged into the ladle.

The inventive method provided:

- reduction in the duration of the heat by 0.5-1.0 min;

- reduction in furnace repairs due to burnout of water-cooled panels by 0.3%;

- carrying out effective waste disposal.

Information sources

1. Technological instruction of OJSC KMK TI 68-ES-007-2003 “Steel smelting and casting in ESPC-2”, Novokuznetsk, 2003. - 52 C.

Claims (1)

The method of steel smelting in an electric arc furnace, including filling scrap metal in a furnace, pouring molten iron, melting, foaming slag by blowing with oxygen and blowing carbon-containing material into the oxidation period, melting into a ladle, characterized in that blast furnace dust is used as carbon-containing material production at an injection rate of 10-100 kg / min and at a flow rate of 2.5-20 kg / t of steel or gas treatment dust at an electric steel production at an injection rate of I 15-150 kg / min and at a flow rate of 3,8-30 kg / t steel.