SU821491A1 - Charge of blast furnage for producing casting synthetic cast iron - Google Patents

Description

(54) CHARGE DIAL FURNACE FOR DETECTION OF CASTING SYNTHETIC CHUGUN

FIELD OF THE INVENTION The invention relates to ferrous metallurgy, in particular to cast iron in a blast furnace. . The closest in technical essence and the achieved result to the proposed is a furnace furnace furnace batch for obtaining foundry synthetic cast iron containing coke, iron ore materials, flux and electric furnace ferrosilicon 1. When using this batch, there is no need for coke to restore the recovered ferrosilicon to the previously reduced electroplate flint. However, a part of the charged coke is spent on melting the supplied ferrosilicon in the blast furnace (0.2-0.25 tons of coke per 1 ton of loaded ferrosilicon), which reduces the efficiency of using this additive. In addition, the degree of silicon utilization of ferrosilicon when the latter is fed to the mixture does not exceed 70-75% and studies show that it is economically feasible to use ferrosilicon when disposing of silicon at least 85%. Therefore, the use of expensive, electric furnace ferrosilicon in a blast furnace in spite of decrease in coke consumption and increasing productivity increases the cost of iron ,. The purpose of the invention is to increase the utilization of silicon, reduce coke consumption and increase the productivity of the blast furnace in the smelting of cast iron. The goal is achieved by the fact that the blast furnace charge, containing coke, iron ore materials and flux, additionally contains a metal-silicon additive from synthetic cast iron production waste with an additive of ferrosilicon to liquid iron in the following ratio of components, wt.%: Coke flux Meta. 8-2.0 additive Iron ore mateal rials At the same time, the metal silicon additive has the following chemical composition, weight,%: SiC3-7 SiO2 Csvov15-26. Remaining With the addition of ferrosilicon to the ditch, a large difference in the specific gravities of liquid iron and lump ferrosilicon causes the rapid emergence of insoluble ferrosilicon pieces on the surface of the iron. The low specific surface of pieces of ferrosilicon leads to a prolongation of the dissolution processes of ferrosilicon and a decrease in the efficiency of its use, despite the use of such complex mechanical means as agitators and chute septums. Studies show that with a regulated supply of ferrosilicon, the degree of utilization of ferrosilicon does not exceed 85-90%. When ferrosilicon is supplied to a ditch in a cast iron ladle, a refractory crust is formed on the surface of the iron, consisting of tangled, cast iron, the constituents of undissolved ferrosilicon, graphite, etc. The chemical composition of the crust, wt.%: Si er15-20 SiC3-7 SiO21-3 CCBOB15-26 Fe v erOther The amount of the crust formed when applying ferrosilicon to the ditch is 0.4-2.0% of the weight of synthetic cast iron, while The fraction of unutilized silicon in the crust is 1015% of the amount of silicon additionally introduced. After draining the synthetic iron from the ladle, the ladle is cleaned of the crust remaining in it. The latter is subsequently not used and is directed to the slag dump. The preparation of the metal-silicon additive for use in the charge is concluded in crushing the crusts to a fraction of less than 100 mm and cleaning it from graphite sang by air separation or another method.

Proizvovitvlnoot.

furnaces,% 100.0 100.9 103.9 105, 107, “The coke consumption of coke, kg / t chug. 617 "12.3 593.5

Srvdiek adramm

CHV kolvvayi,

silicon content. .

; cast iron,% 0.166 0.234 0.169 0.166 0.166

, 5 102.7 98.6

0.166 0.1.66 0.166 For supplying the prepared metal-silicon additive to the charge, the additive accumulates in the ore yard or in the bunkers of the blast furnace loading section. The consumption of the additive in the charge is determined based on obtaining a predetermined increase in the silicon content in the iron in an amount of 0.8-2.0% of the weight of the charge loaded. When the additive is supplied less than 0.3 of the weight of the charge, there is an uneven distribution of silicon in the iron due to the small amount of the additive supply. The increase in consumption of more than 2.0% of the weight of the charge leads to blockage of the hearth of the blast furnace with excess graphite, a decrease in the productivity of the blast furnace. This is evidenced by conducted in the blast furnace of the Tulacher- Scientific and Production Association. met research (ohm. Table 1). The use of a metal-silicon additive does not require additional consumption of coke to melt it, so. how long the carbon contained in the additive is used for this purpose. The consumption of coke in the charge depends on the specific operating conditions of the blast furnace furnace, the iron content in the charge, the degree of preparedness of the charge, the consumption of hydrocarbon-containing additives to the blast, the temperature of hot blowing, etc. When reducing the coke consumption less than 17.0%, the necessary heat supply is not provided to ensure the charge melts and the reduction reactions in the blast furnace are complete; an increase in the coke consumption above / 32.0% is impractical due to a significant overheating of the heat, a sharp deterioration in technical and economic indicators domain process. Flux consumption is determined by the degree of readiness of the iron ore part. charge. Changes in the indicators of blast furnace smelting at various costs of metal – locking additive (experiments were carried out on a blast furnace with a volume of 1386 m L smelting-cast iron). Tbln 1 582.1 571.2 560.0 570.4 564.3 With fully agglomerated agglomerate, the flux consumption is at least 1% of the weight of the charge to compensate for oscillations in the basicity of the sinter, when the blast furnace is operating on The charge from sypholized fluids flux consumption increases to 20% of the weight of the charge. Example. In the Scientific Production Association Tulachermet on blast furnace No. 3 to useful objects, 2000, synthetic casting iron is produced by regulated aggregate crushed ferrosilicon to the cast iron ditch into the iron flow. The consumption of FS-45 electrical ferrosilicon with a pressure of 25-30 kg / t of pig iron. The daily production of synthetic foundry iron complies with 80% of the total production of pig iron in this furnace, or 2,700 tons of pig iron / / day. At the site of the casting machines after the casting of synthetic cast iron, ladles are cleaned of crusts and accumulated in the latter, in specially designated cars. After filling the car, it is sent to the area where the crusts are crushed and subjected to air separation, after which the prepared metal-silicon additive is fed into the cars to the bunker ramp of the blast furnace, where it is accumulated in specially selected bunkers. In 14 days of work, 486 tons of refractory crusts were obtained at the site of the spreading machines, which is 1.29% of the weight of synthetic cast iron. The degree of utilization of ferrosilicon in this case is 87%. After crushing and cleaning the corr, from the graphite sang in the pile-working workshop, the yield of the prepared metal-reinforcing additive was 465 tons or 95.7% of the weight of the refractory crusts. The average chemical composition of the additive, wt.%: The melting of these additives is carried out on blast furnace No. 1 with a useful volume of 1386 m. In the base period, the furnace is operated; known batch, consisting of tons of coke (25.9% by weight of the mixture), sinter (61.0%), 3.0 tons of pellets (12.2%) and 0.4 tons of flux (1.6% ) in each filing. After calculating the consumption of the metal-silicon additive, the increase in the content of silicon in the iron by successively is 0.3 abs.%, 0.5 abs.%, 0.75 abs.%, With the degree of silicon utilization in the furnace 0.7, the additive is introduced in the following quantity: And the period is the calculated increase in the silicon content in the iron by 0.5 abs.%. 0.35 tons of additives in the feed (1.4% by weight of ishkhta). The length of the period is 2 days. Speriod-with a calculated increase in the silicon content in the iron at 0.75 abs.% 0.50 tons of additives in the feed (2.0,% by weight of the mixture). The duration of the period No. is 2 days. In order that the metal-silicon additive does not fall into the peripheral zone of the blast furnace, it is loaded onto the bottom of the second ore grade of each feed. The technological parameters of the blast furnace operation (flow rate, pressure, temperature, flow, humidity, natural gas flow, etc.) are practically unchanged. Technical and economic indicators of the blast furnace in the base and experimental periods are given in table. 2. The compiled silicon balance during patney periods shows that the transition rate of silicon to cast iron from the ethyl-silicon additive is 71.2.

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Claims (1)

1. Blast furnace charge to obtain casting synthetic cast iron,: coke-sticking, iron ore mats: fluxes and flux, characterized by the fact that, in order to increase silicon utilization, save i-consumption and increase productivity of the blast furnace, the charge additionally: metal-silicon additive i3 of synthetic iron production waste in the following ratio of components, weight,%: Cox17-32 Flux1-20 Metalplaster additive0,8-2,0 Iron ore materials Else 2, Charcoal according to claim 1, o: T l and h and the fact that the metal-silicon additive has the following chemical composition, wt.%: 31met15-20 SiC3-7 Si02 1-3 15-26 From the Rest Sources of information taken into account in the examination 1. Increasing the silicon content in the iron through the use of ferrosilicon. Report TsL of Novotulsky metallurgical plant. ZIINCHM card file, M., 1968, series 15, p. 213.