RU2237721C1 - Method of blast-furnace smelting of alkali-zinc-containing charges - Google Patents

Abstract

FIELD: ferrous metallurgy; blast-furnace smelting.

SUBSTANCE: proposed method includes loading the charge containing alkali and zinc, putting-on the blast, monitoring the temperature and outlet of blast-furnace gas, forming the buffer layer by charging the fractionated slag crushed stone and coke in blast furnace, reducing the level of charge to horizon at temperature of 750-800 C; provision is made for cooling the gas on furnace top to 480-500 C by delivery of water to furnace top space to exclude overheating of metal structures of furnace top and to convert alkali and zinc vapor to solid state.

EFFECT: enhanced efficiency of removal of zinc and alkali from furnace.

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Description

The invention relates to ferrous metallurgy and can be used in blast furnace smelting of materials containing alkali and zinc.

A known method of blast-furnace smelting of zinc-containing charges [1], including loading a charge containing zinc, blowing, monitoring the temperature and output of blast furnace gas, loading coke with determining the layer height, periodically lowering the level of charge charge.

The disadvantage of this method is that a significant amount (45-90 tons) of deficient coke and the alkali yield, with a high yield of zinc, are not sufficiently effective for the formation of the buffer layer at a time.

The closest in technical essence and the achieved result is a method for blast-furnace smelting of zinc-containing charges [2], which includes loading a charge containing zinc, blasting, monitoring the temperature and output of blast furnace gas, loading and forming a buffer layer of a certain height, periodically lowering the level of charge charge to increase temperature of blast furnace gas up to 450-500 ° C, and the buffer layer is formed from a layer of coke and fractional slag crushed stone.

The disadvantage of this method is the insufficiently high degree of zinc removal and a low degree of alkali removal.

The present invention solves the problem of efficient removal of zinc and accumulated alkalis from the furnace.

To achieve this result in the method of blast-furnace smelting of alkali and zinc-containing charges, including loading a charge containing zinc, blasting, controlling the temperature and output of blast furnace gas, loading coke and fractional slag crushed stone, forming a buffer layer of a certain height, periodically lowering the level of charge charge, the level of the mound is lowered to the horizon with a gas temperature of 750-800 ° C, and to cool the gas at the top to 480-500 ° C, water is fed into its working space.

The proposed method is based on the fact that an increase in gas temperature (up to 500 ° C for zinc and up to 750-800 ° C for alkalis) leads to the fact that the transition from vaporous, liquid to solid occurs outside the column and this leads to more significant destruction of the circuits of substances. Their removal from the furnace with respect to the removal during normal operation of the blast furnace increases tenfold. To ensure such conditions, the level of mound should be lowered to the horizon with a temperature that provides the maximum removal of alkalis - 750-800 ° C.

The need to cool the gas at the top to 500 ° C and below is due to the restriction imposed by the technological instructions for the blast furnace process, according to which the operation of the filling apparatus in an environment with a temperature above 500 ° C is possible for no more than 10 minutes.

The proposed method was tested on a blast furnace with a volume of 1373 m ³ .

Before testing the method, the furnace worked with the following parameters. The charge was loaded, consisting of local sinter (57%), pellets of the Sokolovsko-Sarbaisky GOK (39%) and Mikhailovsky GOK (4). The gas output was 1385 m ³ / t of cast iron with a temperature of 280 ° C. The operating position of the charge charge level is 2.75 m from the edge of the large cone. The estimated height of the buffer layer is 8 m, for which 24 skips of fractionated slag crushed stone (12 t / skip) and 18 skips of coke (3.7 t / skip) were loaded.

At 9 hours and 15 minutes, the alkali and zinc-containing charge was stopped; at 9 hours and 30 minutes the parameters of the blast were changed, as a result of which the gas output decreased from 235 to 195 thousand m ³ / h (Table 1). At 9 h 35 min, the formation of a buffer layer was started by loading 12 feeds, including 6 feeds with 1 skip of fractional slag crushed stone and 2 skips of coke and 6 feeds with 3 skip of crushed stone and 1 coke skip. Download was carried out, focusing on the temperature of blast furnace gas 480-500 ° C.

The last supply of crushed stone and coke was loaded at 11 h 40 min. At 11 hours and 50 minutes, 22 m ³ / min of water began to be supplied to the top of the furnace. The level of mounds was lowered to the horizon with a gas temperature of 750-780 ° C for 20 minutes.

At 12 hours and 10 minutes, the water supply was stopped and 1 skip of crushed stone and 2 skips of coke were loaded into the furnace, after which they started loading a normal iron ore charge. At 13 h 50 min, the working position of the mound level, the parameters of the blast, the consumption of natural gas and oxygen were restored.

At this event, the alkali and zinc removal from the blast furnace was completed. Over its entire period, every 5 min, samples of slurry water leaving the wet gas purification system were taken. The results of their analysis are given in table.2.

Based on the data obtained, it was determined that 0.7 tons of potassium, 0.6 tons of sodium and 1.4 tons of zinc were removed from the blast furnace using the method. The blast furnace performance indicators before and after the event are given in table 3.

Thus, the experimental data presented confirm that the application of the proposed method provides the effective removal of alkalis and zinc from a blast furnace, melting the charge containing them.

Sources of information

1. RU patent No. 2058394, IPC C 21 V 5/00, 04/20/1996.

2. RU patent No. 2074893, IPC C 21 V 5/00, 1997.

Claims (1)

The method of blast-furnace smelting of alkali and zinc-containing mixture, including loading a mixture containing zinc, supplying blast, controlling the temperature and output of blast furnace gas, loading coke and fractioned slag crushed stone, forming a buffer layer of a certain height, periodically lowering the level of charge charge, characterized in that the level the mounds are lowered to the horizon with a gas temperature of 750-800 ° C, and to cool the gas at the top to 480-500 ° C, water is fed into its working space.