RU2318024C1 - Method of the non-coke reprocessing of the mining raw with production of the vanadium-alloyed steel - Google Patents

Abstract

FIELD: ferrous metallurgy; other industries; methods of the non-coke reprocessing of the mining raw with production of the vanadium-alloyed steel.

SUBSTANCE: the invention provides, that in the gasifier they produce the cast-iron and the hot reducing gases with the temperature of 850-1050°C by the coal gasification, exercise the loading of the raw and feeding of the hot reducing gases in the shaft furnace for the metallic coating, the metallic coating and the subsequent smelled of the metallized raw in the arc furnace. The necessary temperature in the gasifier maintain by the additional electrical heating. At that up to 70 % of the supplied energy is the electric power. Usage of the invention allows to reduce up to 70 % entry of the sulfur and phosphorus from the coal into cast iron and accordingly to reduce the content of the sulfur and phosphorus in the alloyed steel that improves its operational costs at the steel production. Besides the sulfur contents in the effluent gases of the shaft furnace of the metallization is reduced. At that the oxygen consumption is also reduced and the reducing gas reduction potential of reducing gas is increasing, the process of metallization is accelerated and the degree of the metallization increases, that result in the drop of the consumed electric power in the arc electrical furnace and its efficiency increases.

EFFECT: the invention ensures reduction by near to 70 % of the share of the sulfur and phosphorus transferred from the coal into cast iron and accordingly to reduce their content in the alloyed steel, that improves its operational costs at the steel production.

1 dwg, 1 ex

Description

The invention relates to metallurgy, in particular to metallization processes and electric steel production.

Known methods for the direct alloying of steel and alloys, in which the alloying elements come directly from the original natural raw materials (concentrates, agglomerates, pellets [1-3]). In this case, a gasifier operating in a mixed mode is used - with the simultaneous production of hot reducing gases for metallization of the feedstock and the intermediate product - cast iron. Further, metallized raw materials containing alloying elements - vanadium, nickel, etc., together with naturally-alloyed cast iron are fed into an electric furnace to obtain the finished product of alloy steel (vanadium) or alloy (ferronickel). However, the disadvantage of this method is the use of coal as the sole source of energy for the gasification process and the production of pig iron. It is known that phosphorus and sulfur contained in coal in a significant amount pass into the metal and gas phase during this process, which creates environmental problems and affects the quality of the metal.

Thus, a known method of direct alloying of steel with vanadium [1], which is closest to the proposed invention and adopted as an analogue. However, the disadvantage of this method is the use of coal as the sole source of energy for the gasification process. This causes the appearance of significant amounts of sulfur and phosphorus in the reducing gas and cast iron, which worsens the environmental situation and the quality of the metal and complicates the technology of smelting in an electric furnace. In addition, to obtain the required amount of heat in the gasifiers, oxygen is used, supplied through the upper tuyeres for the afterburning of carbon monoxide. This reduces the reduction potential of the reducing gases, slows down the metallization process, reduces the degree of metallization, and as a result, leads to an increase in the melting time in an electric arc furnace.

The technical task of the invention is to provide improved quality of the alloyed metal, reducing emissions of sulfur dioxide in the atmosphere with direct alloying of steel and alloys, increasing the productivity of the installation. This problem is solved as follows.

A method is used for cokeless processing of ore raw materials to produce vanadium-alloyed steel, which includes the production of hot reducing gases and cast iron in a gasifier at a temperature of 850-1050 ° C by coal gasification, loading of raw materials and supply of hot reducing gases to a shaft furnace for metallization, metallization and subsequent melting of metallized raw materials in an electric arc furnace, characterized in that the required temperature in the gasifier is maintained by additional electric heating, and up to 70% th power of the electricity supply.

The gasification process for producing reducing gas for the metallization of raw materials is carried out in a gasifier, working in this way on two energy sources - electric and coal energy. At the same time, the energy costs for heating and melting the raw materials of a gasifier working using a liquid bubbling, slag bath or with a coke nozzle are compensated using electric energy, and carbon-containing materials are used only to produce reducing gas and to restore the original ore materials. Calculations show that in the heat balance of the gasifier of hot reducing gases, operating in a mixed mode, up to 70% of the input energy is allocated to heating and melting of the starting materials (ore concentrate, coal, fluxes) and goes into heat content, and the rest of the energy is spent on reducing gases and metal recovery from ore materials (endothermic reactions). Thus, up to 70% of the supplied energy can be replaced by electric energy. At the same time, the consumption of coal (coke) is reduced to 70%, and, accordingly, the content of sulfur and phosphorus in the reducing gas and cast iron is reduced.

In particular, when the content of phosphorus pentoxide P ₂ O ₅ in coal is 0.1%, its content in the metal without the use of electricity is on average 0.05-0.1%, and with the use of electric energy in the amount of 70% by heat, the phosphorus content in metal will decrease by 70% and will be approximately 0.015-0.03%.

This allows for the further supply of metallized raw materials (concentrate, pellets) and cast iron to an electric arc furnace to produce alloy steel (alloy) without complications to carry out the oxidative and reduction melting period, since the transfer of phosphorus in the recovery period from slag to metal will be small - up to 70% less than when using only coal as an energy source in the gasifier. With the proposed method, there is no need to obtain additional heat due to the partial afterburning of the reducing gases over the slag bath.

The use of electric energy in the gasifier allows, therefore, to abandon the use of afterburning of carbon monoxide. At the same time, the reduction potential of reducing gases increases by 20%, which leads to an acceleration of the metallization process and an increase in the degree of metallization in a shaft furnace. This in turn leads to a decrease in the duration of melting in an electric furnace and an increase in the productivity of the process. In addition, the required oxygen consumption is reduced by 40-50%.

This method is implemented using the device shown in the drawing, where SHG is a hot reducing gas; VG - reducing gas; EG - export gas; η _p - the degree of recovery.

The device includes an electric coal gasifier for hot reducing gases 1, a furnace for metallizing iron ore (pellets, concentrate) 2, an electric arc furnace 3, an electric heating device and electrodes of a gasifier 4, tuyeres for supplying an oxidizer (oxygen-rich blast) 5, a device for loading ore materials and coal 6 , a pipe for hot reducing gases 7, a second stage recuperator for heating the oxidizer 8, a recuperator for heating the first stage oxidizer 9, an oxidized ore loading device rye into a metallization furnace 10, a device for introducing reducing gases into a metallization furnace 11, a device for unloading metallized raw materials 12, electrodes of an electric arc furnace 13, a device for casting iron into an electric furnace 14, a device for supplying metallized raw materials to an electric furnace 15, a device for supplying scrap metal to an electric furnace 16, fuel - oxygen burners 17, a pipeline for discharging blast furnace gas from a metallization furnace - export gas 18, a cooler for SHG and cleaning it from dust 19, cleaning blast furnace gas from dust 20, an exhaust device guna 21 from the gasifier.

The device operates as follows.

Ore materials containing an alloying element and coal are fed into the gasifier through a loading device. Through the tuyeres, an oxidizer (oxygen enriched air) is supplied to the gasifier. The resulting hot reducing gases are fed through a pipe to the heat exchanger of the second heating stage, and the oxidant heated in the heat exchanger of the first stage enters the same heat exchanger. The reducing gas cooled in the recuperator enters through the reducing gas input device into the metallization furnace. Through the device for loading ore raw materials, oxidizing ore raw materials (pellets) containing an alloying element enter the metallization furnace. Metallized ore raw materials are fed through a device for supplying metallized ore raw materials to an electric furnace. Through the device for casting iron and supplying scrap metal, liquid iron and scrap are also fed into the electric furnace. Through fuel and oxygen burners, we supply heat additional to electric energy to the electric furnace. In this case, blast furnace gas export gas can also be used. The rest of the blast furnace gas is exported and discharged through the pipeline. In the cooling and purification device for hot reducing gases, partial cooling and purification of SHG from dust is carried out, and in the device for purifying blast furnace gas, blast furnace gas from the blast furnace is cleaned from dust. From the gasifier, the resulting intermediate (cast iron) is discharged through the cast iron exhaust device.

Using this method allows to reduce up to 70% the supply of sulfur and phosphorus from coal to cast iron and, accordingly, to reduce the content of phosphorus and sulfur in alloyed steel, which improves its operational properties and reduces operating costs for the production of steel. At the same time, oxygen consumption is reduced, the reducing gas of the gasifier has a greater reducing potential, which accelerates the metallization of iron ore and increases the degree of metallization. At the same time, the energy consumption in the electric arc furnace is also reduced and its productivity is increased. In addition, the sulfur content in the exhaust gases of the metallization shaft furnace is reduced.

Example 1. According to the proposed method, the gasifier has dimensions:

Dimensions of horizontal section at the level of the lower tuyeres:

Area, m ² 28 Length m eleven Width m 2,5

Height:

Working space from the bottom to the arch, m 6.0 From the bottom to the lower tuyeres, m 1,5 From the bottom to the holes for the electrodes, m 4.0

At the gasifier outlet, cast iron is produced. Accordingly, based on 1 ton of pig iron, 2.16 tons of coal, 1682 kg of ore, 11 kg of lime, and a blow of lower tuyeres of 2049 kg are loaded at the outlet of the gasifier. The necessary heat for heating and melting of the starting materials (ore concentrate, coal, fluxes) is provided by electric heating. The energy spent on obtaining reducing gases and the recovery of metal from ore materials (endothermic reactions) is provided by the afterburning of coal. The power of the transformer is 50-140 MV · A, the current strength is 30-80 kA. The number of electrodes is three.

Thus, at the outlet of the gasifier, it turns out: 1 ton of cast iron, 4760 m ³ / h of SHG, 494 kg of slag, 115 kg of dust. Due to electric heating, the reduction potential of reducing gases increases by 25%.

Composition of SHG: СО - 65%; H ₂ - 23%; N ₂ - 12%; СО ₂ - 0%; H ₂ O - 0%.

Used Books

1. Lisienko V.G., Romenets V.A., Parenkov A.E. etc. A method of coke-free processing of vanadium-containing ore raw materials to produce vanadium-alloyed steel. RF patent №2167944, Priority from 08/11/1998, bull. No. 15, 05/27/2001.

2. Parenkov A.E., Lisienko V.G., Chistov V.P., Yusfin Yu.S. et al. Method for processing nickel-containing iron ore raw materials. RF patent No. 2217505, Priority dated March 22, 2002, Bull. No. 33, 11/27/2003.

3. Lisienko V. G., Fainshmidt E. M., Druzhinina O. G. Structural steel. RF patent №2217519, Priority dated 6.06.2001, bull. No. 33, 11/22/2003.

Claims (1)

A method of coke-free processing of ore raw materials to produce vanadium-alloyed steel, comprising producing cast iron and hot reducing gases with a temperature of 850-1050 ° C in a gasifier by gasifying coal, loading raw materials and supplying hot reducing gases to a shaft furnace for metallization, metallization and subsequent melting of metallized raw materials in an electric arc furnace, characterized in that the required temperature in the gasifier is maintained by additional electric heating, and up to 70% of the supplied energy It supplies electricity.