SU1715857A1 - Converter steelmaking process - Google Patents

Description

The invention relates to the field. ferrous metallurgy, more specifically to the methods of steel smelting in oxygen converters

The purpose of the invention is to ensure trouble-free and lime saving.

When creating the invention, proceeded from the need to transfer the liquid final slag to the inactive state and determine the moment of downloading the intermediate slag after oxidation of the silicon of the metal bath, since during the casting of the cast iron and during the oxygen blowing, an emergency occurs because of its interaction with the active iron. blade slag, and the presence of siliceous slag in the converter destabilizes the purge and dramatically impairs the processability of smelting.

The introduction of scrap into the final liquid slag leads to the transfer of slag to an inactive state due to its cooling with scrap, which prevents metal from being ejected when the iron is drained into the converter and stabilizes the flow of the blown metal.

Downloading of intermediate slag should be carried out when carbon oxide is contained in the exhaust gases. kind after 30-40% of the duration of the purge. This makes it possible to remove silicon in the form of silica from the converter bath as much as possible, which ensures a drastic reduction in lime consumption and the prevention of metal and slag emissions during the oxygen blowing process.

When downloading an intermediate slag when the content in the exhaust gases is less than 45% carbon monoxide and less

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30% of the duration of the purge does not achieve complete oxidation of silicon and its removal from the converter

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the consumption of lime in the second period of purging and destabilization of purging. When an intermediate slag is downloaded, the content of 50% carbon monoxide and more than 0% of the purge duration in the off-gas of the exhaust gas drops out during the period when intensive interaction of carbon in the metal with iron oxides in the slag begins, it leads to emissions and removal of metal-75 of thall and slag from the converter, reducing the metal yield and increasing the consumption of pig iron. In addition, in this case, the heat loss from the slag is increased due to the increased temperature and the consumption of pig iron increases.

The essence of the method is to ensure the failure-free process by preventing claps, explosions, emissions from the converter during casting of iron and during oxygen production, and reducing lime consumption by removing silicon with intermediate slag

Testing of the proposed method of steel melting was carried out in 350-ton converters of the Cherepovets Steel Mill. When conducting melts used cast iron with a content of 85% carbon; 0.60% manganese silicon; 0.055% phosphorus formula; 0.021% sulfur at. The purge with oxygen was carried out with control of the process according to the composition and consumption of flue gases.

Example. On the left final slag of the previous smelting in the amount of k2 t with basicity (CaO + MgO) / Si02 3.55, 123 tons of scrap are poured and 281 tons of pig iron are poured, followed by oxygen blowing. With 5% carbon monoxide in the flue gas and a purge duration of 5.8 minutes (35%):

After downloading the intermediate slag from the converter, the process continues.

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duvka to soda and the temperature of the period of production of lime. The construction is carried out by n technology with SiMn, FeSi and A | holding 0.15 | ni; 0, C% mar 0,011% phosphorus Consumption of melt 773; lime k 19900 m3 in the current period. But, without cotton situations, pig iron and the like.

The results for the proposed are given

The analysis of the rezu shows that to ensure the reduction of consumption in the case of the introduction of slag and the slag with soda gases during the flow of air B, this decreases to 19 kg / ton.

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The method of recovery, including those of the final fluid, the filling of the pump with the control and the interstitial flow is the key to ensure and save money from the liquid final

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download to waste

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Formula

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blow to carbon content of 0.08% and temperature. During the second period of purging, 15.7 tons of lime are sown. The deacidification and carburization is carried out on the existing technology in the workshop with additives into the coke bucket; SiMn, FeSi and A1. Steel is obtained with a content of 0.15% carbon; 0.18% cream; nor; 0, C% manganese; 0.021% sulfur; 0.011% phosphorus and 0.038% aluminum. Consumption for smelting, kg / t steel: cast iron 773; lime k3. Oxygen consumption is 19,900 m3, including 7,000 m3 in the first period. Melting was normal, without claps, emissions and emergencies when filling scrap, pouring iron and purging the metal with oxygen.

The results of the heats, carried out by the proposed method and the known, are shown in table

Analysis of the results of the experimental heats shows that the best results for ensuring trouble-free operation and reducing lime consumption are obtained if scrap is introduced into the liquid final slag and intermediate slag removal when carbon monoxide is contained in exhaust gases after the purge duration has elapsed. In this case, lime consumption is reduced by 22 kg / t and pig iron at 19 kg / t.

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Formula

The steelmaking method in the converter, which includes leaving the final liquid slag in the unit, introducing scrap, pouring iron, purging with oxygen and controlling the process of the process on the composition and consumption of exhaust gases, intermediate slag loading, and so on. to ensure trouble-free operation and economy of lime, scrap is introduced into the liquid final slag, and intermediate

Downloading begins when the carbon monoxide content in the exhaust gases is after 30-MO% of the purge duration.

Claims (1)

Claim A method of steel smelting in a converter, including leaving the final liquid slag in the unit, introducing scrap, pouring cast iron, purging with oxygen to control the process according to the composition and consumption of exhaust gases, intermediate slag downloading, which are necessary to ensure trouble-free and saving lime, the scrap is introduced into the liquid end of the tail, and the intermediate download begins when the content in the exhaust gases is 45-50% of carbon monoxide--. sort after 30 “40% of the purge duration. 1715B57 {co] in WASTE ”ceme gas Purge duration in the first period L Lime consumption Cast iron consumption, kg / t The content in the metal, J The characteristic. swimming trunks. Steel output , t kg / t t S R 45 40 43 15.7 773 0,021 0.011 Normal 363.9 * • 7 35 43 15.7 773 0,021 0.011 _n_ 363.9 fifty thirty 43 15.7 773 0,021 0.011 363.9 th 35 56 20.1 782 0,021 0.016 Emergency 359.7 52 35 56 20.1 782 0,021 0.016 359.7 47 29th 56 20.1 782 0,021 0.016 _ir_ 359.7 47 41 56 20.1 782 0,021 0.016 -N. 359.7 Prototype - 20 65 23.1 792 0,023 0.018 ^ 11-. 3? 5.2 Compiled By ₀ Samsonov Reda KTRR 0 Tehred m. Didyk Proofreader A. Obruchar Order 580 Circulation Subscription VNIIIPI State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035, Moscow, Zh-35, ’Raushskaya n ^ b., D. 4/5 Production and Publishing Plant Patent, Uzhgorod, st. Gagarina, 101