CN108411056B - Method for using lump ore in blast furnace at large proportion - Google Patents

Abstract

The invention discloses a method for using lump ore in a blast furnace with large proportion, which comprises the following steps: step one, carrying out high-temperature metallurgical property measurement on the fed lump ore, and selecting the lump ore meeting the conditions; step two, fully mixing the lump ore and the coke particles into a mixture according to the mass ratio of 6: 1-25: 1; and step three, adding the mixture obtained in the step two to the middle ring belt of the blast furnace according to the mass ratio of the lump ore amount in each batch of furnace burden to each batch of furnace burden being 1: 10-3: 10, and smelting in the furnace. According to the invention, lump ore is fed into the furnace in batches, so that the feeding proportion of the lump ore is greatly improved on the premise of ensuring the stable and smooth operation of the blast furnace; the permeability index of the mixture is good and the efficiency of blast furnace gas is reduced by optimizing parameters such as the mixing ratio of lump ore and coke briquette; the invention also prolongs the retention time of the coal gas in the furnace, improves the utilization efficiency of the blast furnace coal gas, reduces the energy consumption of the blast furnace and greatly reduces the cost of the raw materials entering the furnace.

Description

Method for using lump ore in blast furnace at large proportion

Technical Field

The invention relates to a blast furnace smelting method, in particular to a method for using lump ore in a large proportion in a blast furnace, and belongs to the technical field of metallurgy.

Background

The iron-making raw materials of the modern blast furnace comprise iron-containing raw materials such as sinter, pellet, lump ore and the like, and the proportion of the existing large-scale blast furnace sinter generally reaches about 70 percent. Because the sintering ore is an alkaline iron-containing raw material, in order to ensure a slagging system, a blast furnace usually needs to use a certain proportion of acidic iron-containing raw material pellets and lump ores. The grade of lump ore mainly used by blast furnace is often over 60%, for example, the lump ore mainly used by some iron works is south Africa lump and Australia lump, and the iron-bearing grade is close to or even over pellet ore (Hubei pellet, Chengqiu), as shown in Table 1. With the implementation of high-efficiency smelting technology of blast furnaces, the demand of pellets in iron plants is high, but is limited by the capacity of the pellet plants, and the price of the pellets rises due to the price of raw materials and fuel required by pellet preparation in recent years, so that the use of the pellets in large quantity is limited. The blast furnace aims at ensuring the grade and slagging system of the iron-containing raw materials entering the furnace, and improving the proportion of lump ore with high iron-containing grade entering the furnace becomes the main trend of high-efficiency smelting of the domestic large blast furnace.

In the process of actually increasing the blast furnace lump ore proportioning, a great problem is found to exist. For example, the ratio of the blast furnace lump ore in No. 4 of a certain iron works was increased from 8.51 wt% in 2015 to 15 wt% or more at present, as shown in Table 2. The iron-containing material pellets fed into the blast furnace are mature ores, the lump ores are raw ores, the iron-containing grades of the two are similar, but the metallurgical properties of the two are greatly different, as shown in Table 3. Along with the increase of the charging proportion of lump ore, the temperature of nine and ten sections of cooling walls of the No. 4 blast furnace is reduced, the temperature value of ten sections of cast steel cooling walls reaches below a reflow zone, and the temperature value of the cooling walls of a dripping zone, namely the root position of the reflow zone, covers to eleven sections of the furnace body (shown in Table 4). After the charging proportion of the blast furnace lump ore is increased and the charging proportion of the pellet ore is reduced to zero, the position of the blast furnace soft melting zone is moved upwards, the furnace body of the blast furnace is easy to be bonded, the development of edge airflow is hindered, the air quantity of the blast furnace is reduced, the operation is difficult, and the economic and technical indexes of the blast furnace are deteriorated.

TABLE 1 comparison of chemical Properties (Unit: wt%) of pellets and lump ores in certain iron works

TABLE 2 charging ratio of pellets to lump ore (unit: wt%) in certain iron works

Time of day	Ratio of sinter	Pellet proportion	Lump ore ratio
				2015 years	69.23	22.26	8.51
2016 (year)	68.19	21.78	10.02
				Year 2017, month 5	75.72	6.81	17.47
6 months in 2017	77.90	3.30	18.80
				7 month of 2017	72.08	13.27	14.65
8 months in 2017	70.66	12.53	16.80

TABLE 3 comparison of high-temp. metallurgical properties of blast furnace No. 4 of certain iron works

Iron-containing raw material	Softening onset temperature/. degree.C	Softening end temperature/. degree.C	Softening interval/. degree.C	Melt drop temperature/. degree.C
					Sintered ore	1253	1349	96	>1520
Ezhou pellet	1143	1246	103	1496
					Chengchao pellet	1129	1235	106	1488
Ao block	1053	1239	186	1511

TABLE 4 temperature (. degree.C.) of cooling wall of blast furnace No. 4 in iron works in 2017 and 12 months

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a method for using lump ore in a large proportion in a blast furnace, and under the condition that the charging proportion of the lump ore is increased to 15-30 wt%, the furnace condition of the blast furnace still keeps stable and smooth and the utilization rate of blast furnace gas is high.

The invention is realized by the following steps:

a method for using lump ore in a blast furnace with large proportion comprises the following steps:

step one, carrying out high-temperature metallurgical property measurement on the charged lump ore, and selecting the lump ore which meets the following high-temperature metallurgical property conditions: the softening starting temperature is 150-250 ℃ lower than the softening starting temperature of the sintering ore, or the softening temperature range is 1.5-2.5 times of the softening temperature range of the sintering ore.

Step two, fully mixing the lump ore and the coke particles into a mixture according to the mass ratio of 6: 1-25: 1;

and step three, adding the mixture obtained in the step two to the middle ring belt of the blast furnace according to the mass ratio of the lump ore amount in each batch of furnace burden to each batch of furnace burden being 1: 10-3: 10, and smelting in the furnace.

The further scheme is as follows:

in the first step, the high-temperature metallurgical properties comprise the softening starting temperature, the softening finishing temperature, the softening interval and the molten drop temperature of the lump ore. The softening end temperature-softening start temperature is a softening range, and any 2 of these are limited, and 3 of them are limited. The softening region of the furnace burden affects the position of the softening zone of the blast furnace, the softening starting temperature of the furnace burden is low, the softening region is wide, and the softening zone of the blast furnace moves upwards.

The further scheme is as follows:

in the first step, the high-temperature metallurgical performance of the lump ore is as follows: the softening starting temperature is 171-174 ℃ lower than the softening starting temperature of the sintered ore, or the softening temperature range is 98: 59-198: 125 times of the softening temperature range of the sintered ore.

The further scheme is as follows:

in the second step, the mass ratio of the lump ore to the coke pieces is 9: 1-15: 1.

The further scheme is as follows:

in the third step, the blast furnace adopts a mode of feeding lump ore into the furnace in batches, and each batch of furnace materials are sequentially fed into the furnace according to the sequence of coke, sintering + pellets, coke butyl + lump ore (under the condition that the using amount of the pellet ore is not zero) or the sequence of coke, sintering, coke butyl + lump ore (under the condition that the using amount of the pellet ore is zero).

The further scheme is as follows:

and in the third step, the blast furnace adopts a material distribution matrix from an outer ring to an inner ring, and the mixed material is distributed at the middle ring belt of the blast furnace.

The further scheme is as follows:

in the third step, the block ore consumption in each batch of furnace burden is 3: 20-1: 5 of the batch weight of the furnace burden.

The further scheme is as follows:

the lump ore is an Australian lump, namely an Australian imported lump ore.

Compared with the prior art, the invention has the following advantages:

firstly, after the charging proportion of pellet ore is reduced and the charging proportion of lump ore is improved in the prior art, the softening zone area in the blast furnace is widened and moves upwards, so that the upper area of a furnace body of the blast furnace is easy to be bonded to influence the smooth operation of the blast furnace.

Secondly, by optimizing parameters such as the mixing ratio of the lump ore and the coke breeze, the permeability index of the mixture is good and is equivalent to the permeability index of the original iron-containing furnace burden in the middle zone, so that the mixture is smoothly distributed at the middle zone of the blast furnace without influencing the edge and central airflow of the blast furnace, and the problems that the development of the edge airflow of the blast furnace is easily influenced and the gas efficiency of the blast furnace is reduced by using the lump ore with excessive ratio at the edge of the blast furnace are solved.

Thirdly, the distribution mode of the lump ore mixed coke oven has small influence on the distribution of the inherent gas flow formed in the blast furnace for a long time, the operation change of the blast furnace is small, the furnace type control is simple, the use of the large proportion lump ore also inhibits the gas flow of the middle ring zone in the furnace, the retention time of the gas in the furnace is prolonged, the utilization efficiency of the blast furnace gas is improved, and the energy consumption of the blast furnace is reduced.

Finally, the method of the invention uses a large amount of lump ore, the pellet ore can be used in a small amount or not used, the energy consumption in the pellet making process is saved, the lump ore is cheaper than the pellet ore, and the cost of the raw materials entering the furnace is greatly reduced.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

The softening starting temperature of the blast furnace sintered ore of No. 4 of a certain domestic iron and steel plant is 1226 ℃, the softening finishing temperature is 1351 ℃, the softening temperature interval is 125 ℃, the softening starting temperature of the Australian blocks is 1055 ℃, the softening finishing temperature is 1253 ℃ and the softening temperature interval is 198 ℃;

the No. 4 blast furnace macadamia briquette is loaded with 9t, the nut coke is loaded with 1t, and the two are fully mixed.

The No. 4 blast furnace selects the conventionally adopted batch weight as 60 t;

the No. 4 blast furnace adopts a mode of feeding lump ore into the furnace in batches, and the material distribution sequence is as follows in sequence: coke, sintering + Hubei ball, Australian block + coke;

the No. 4 blast furnace adopts a material distribution matrix from an outer ring to an inner ring, and the material charging matrix is as follows:

wherein C is coke, O represents sintering + jaw ball, K is Australian block + coke butyl, the upper right figure is cloth angular position, and the lower right figure is cloth ring number corresponding to the upper right figure.

When coke is distributed on a blast furnace, the coke is distributed on a No. 9 angle cloth 3 ring, a No. 8 angle cloth 3 ring, a No. 7 angle cloth 2 ring, a No. 6 angle cloth 2 ring, a No. 5 angle cloth 2 ring, a No. 1 angle cloth 3 ring, O, K and the like.

The result shows that the charging ratio of lump ore reaches 15 wt%, the blast furnace keeps stable and smooth operation, the utilization efficiency of coal gas is improved, and the energy consumption is greatly reduced.

Example 2

The softening starting temperature of No. 4 blast furnace sinter of a certain domestic iron and steel plant is 1227 ℃, the softening finishing temperature is 1345 ℃, the softening temperature interval is 118 ℃, the softening starting temperature of Australian blocks is 1053 ℃, the softening finishing temperature is 1239 ℃ and the softening temperature interval is 186 ℃;

the amount of No. 4 blast furnace macadamia blocks is 12t, the amount of coke dices is 0.8t, and the two are fully mixed.

The No. 4 blast furnace selects the conventionally adopted batch weight as 60 t;

the No. 4 blast furnace adopts a mode of feeding lump ore into the furnace in batches, and the material distribution sequence is as follows in sequence: coke, sintering, Australian lumps and coke pieces;

the No. 4 blast furnace adopts a material distribution matrix from an outer ring to an inner ring, and the material charging matrix is as follows:

wherein C is coke, O represents sintering, K is Australian block and coke, the upper right number is a material distribution angular position, and the lower right number is a material distribution ring number corresponding to the upper right number.

The result shows that the charging ratio of lump ore reaches 20 wt%, the blast furnace keeps stable and smooth operation, the utilization efficiency of coal gas is improved, and the energy consumption is greatly reduced.

Although the present invention has been described herein with reference to the illustrated embodiments thereof, which are intended to be preferred embodiments of the present invention, it is to be understood that the invention is not limited thereto, and that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure.

Claims (1)

1. A method for using lump ore in a blast furnace with large proportion is characterized by comprising the following steps:

step one, carrying out high-temperature metallurgical performance measurement on the ore blocks entering the furnace, wherein the softening starting temperature of the sintered ore in the furnace is 1227 ℃, the softening finishing temperature is 1345 ℃, the softening temperature interval is 118 ℃, the softening starting temperature of the ore blocks is 1053 ℃, the softening finishing temperature is 1239 ℃ and the softening temperature interval is 186 ℃;

step two, fully mixing the macadamia blocks in the blast furnace with the loading capacity of 12t and the diced coke with the loading capacity of 0.8 t;

step three, selecting a blast furnace with the conventionally adopted batch weight of 60t, adopting a mode of batch charging of lump ore, and sequentially distributing: coke, sintering, Australian lumps and coke pieces; a material distribution matrix from an outer ring to an inner ring is adopted, and the material charging matrix is as follows:

wherein C is coke, O represents sintering, K is Australian block and coke, the upper right number is a material distribution angular position, and the lower right number is a material distribution ring number corresponding to the upper right number.