Method for strengthening blast furnace smelting under high lump ore proportion

Abstract

The invention discloses a method for strengthening blast furnace smelting under high lump ore proportion, which comprises the following steps of: 1) arranging a lump ore storage bin at the tail of a sintering machine, adding lump ore from a factory from the upper part of a single-roll crusher, cooling the lump ore together with sintered ore in an annular cooler, drying the lump ore in the cooling process, and removing crystal water, the cooled sintered ore and lump ore are fed into a screening device to be screened, and ore with the size of + 5 mm or above is fed into a blast furnace to be smelted; and (2) a blast furnace distribution scheme is adjusted, the ore distribution angle is reduced by 1-3 degrees, the edge gas effect is expanded, the ore angle reduction amplitude is increased along with increase of the lump ore proportion, and strengthened blast furnace smelting under the high lump ore proportion is completed. The lump ore is dried and screened through waste heat generated in sintering production, the powder amount is reduced, the lump ore proportion is effectively increased, and blast furnace energy consumption and carbon emission are reduced.

Description

Technical Field

[0001] The invention relates to the field of blast furnace smelting, and in particular to a method for strengthening blast furnace smelting under high lump ore ratio. Background Art

[0002] In recent years, the steel industry has gradually developed towards refined materials in order to reduce pollutant emissions and reduce ironmaking costs. Reasonable charge structure is an important means to effectively improve the technical and economic performance of blast furnaces. Among blast furnace charges, natural lump ore is cheaper than pellet ore. Some foreign high-quality ores have iron grades that are even better than pellet ore, which can reduce the amount of blast furnace slag after entering the furnace. Moreover, replacing pellet ore with lump ore can reduce the equipment and process of producing pellets, and can greatly reduce energy consumption. Although the reduction of clinker ratio will bring many benefits, the high thermal bursting index of lump ore and the crushing of lump ore caused by the decomposition of crystal water further limit the addition ratio of blast furnace lump ore. The thermal bursting of natural lump ore refers to the bursting phenomenon of natural lump ore during the heating process after entering the furnace due to temperature difference thermal stress or the precipitation of crystal water and carbonate. The thermal bursting of lump ore will produce fragments and fine powder of varying sizes. This is also one of the main defects of natural lump ore as blast furnace charge. It is generally measured by the thermal bursting index (DI -6.3 ) is used to indicate the degree of thermal cracking of lump ore. Therefore, further research is needed to achieve a high proportion of lump ore entering the furnace.

[0003] At present, the lump ore drying process mainly involves newly building a rotary kiln or drum dryer and a screening system to dry and screen the lump ore. This process has the problems of high investment, large footprint, and high energy consumption. Directly adding the lump ore into the blast furnace also leads to an increase in the amount of powder in the furnace, causing the blast furnace to not run smoothly and affecting the lump ore ratio. Summary of the invention

[0004] Purpose of the invention: In view of the shortcomings and defects of the prior art, the present invention provides a method for strengthening blast furnace smelting under high lump ore ratio, which utilizes the waste heat of sintering production to dry and screen the lump ore, reduce the amount of powder, effectively increase the lump ore ratio, and reduce blast furnace energy consumption and carbon emissions.

[0005] Technical solution: A method for strengthening blast furnace smelting under high lump ore ratio of the present invention is characterized by comprising the following steps:

[0006] 1) A lump storage silo is set at the tail of the sintering machine. The lump ore arriving at the factory is added from the top of the single roll crusher and cooled in the ring cooler together with the sintered ore. The lump ore is dried during the cooling process and the crystal water is removed. The cooled sintered ore and lump ore are sent to the screening device for screening, and those with a diameter of +5mm are sent to the blast furnace for smelting;

[0007] 2) Adjust the blast furnace charging plan, reduce the ore charging angle by 1°-3°, expand the edge gas effect, and increase the degree of reduction in the ore angle as the lump ore ratio increases, thus completing the intensified blast furnace smelting under high lump ore ratio.

[0008] Wherein, in the step 1), the waste heat generated by the sintered ore is used to dry and screen the lump ore.

[0009] Wherein, the cooling time in step 1) is 30 min-90 min.

[0010] Wherein, in the step 1), after cooling, the temperature of the sintered ore and lump ore is lower than 150°C.

[0011] Wherein, the total proportion of blast furnace lump ore added in step 2) is 25%-40%.

[0012] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the present invention makes full use of the waste heat of the sintering ring cooler, and after the lump ore added to the blast furnace is dried and preheated, the crystal water and carbonate in the lump ore are decomposed and removed in advance before entering the blast furnace, which can effectively reduce the energy consumption of the blast furnace. By adjusting the blast furnace charging system, the lump ore ratio in the blast furnace can be increased, achieving the effect of energy saving and consumption reduction, and reducing carbon emissions. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0014] The method for strengthening blast furnace smelting under high lump ore ratio of the present invention comprises the following steps:

[0015] 1) A lump storage silo is set at the tail of the sintering machine. The lump ore arriving at the factory is added from the top of the single-roll crusher and cooled in the ring cooler together with the sintered ore. The lump ore is dried during the cooling process and the crystal water is removed. The cooled sintered ore and lump ore are sent to the screening device for screening, and those with particles above +5mm are sent to the blast furnace for smelting. The lump ore is dried and screened by the waste heat generated by the sintered ore. The cooling time is 30min-90min. After cooling, the temperature of the sintered ore and lump ore is lower than 150℃.

[0016] 2) Adjust the blast furnace charging plan, reduce the ore charging angle by 1°-3°, expand the edge gas effect, and increase the reduction of the ore angle with the increase of the lump ore ratio, so as to complete the intensified blast furnace smelting under the high lump ore ratio. The total proportion of lump ore added to the blast furnace is 25%-40%.

[0017] Increasing the ratio of lump ore is one of the important ways to save energy and reduce carbon emissions in blast furnaces, but the lump ore contains a high content of crystal water, which is prone to bursting inside the blast furnace, resulting in serious pulverization, which increases the difficulty of blast furnace operation and energy consumption. The present invention provides a method for strengthening blast furnace smelting under high lump ore ratio, firstly, the lump ore is classified according to different thermal bursting properties, the lump ore is dried by using sintering waste heat, the powder amount is reduced by using the screening system after the sintered ore is cooled, and then the sintered ore and the lump ore are added to the blast furnace for smelting, and the distribution state of the blast furnace charge is optimized by adjusting the distribution system, thereby realizing low-carbon and high-efficiency smelting of the blast furnace under high ratio lump ore conditions.

[0018] The present invention utilizes sintering waste heat to dry lump ore, sieving to reduce the amount of powder, and then adding the sintered ore and lump ore into a blast furnace for smelting, thereby achieving low-carbon and high-efficiency smelting in the blast furnace under the condition of high-proportion lump ore.

Claims

1. A method for strengthening blast furnace smelting under high lump ore ratio, characterized in that: The steps include: 1) A lump storage silo is set at the tail of the sintering machine. The lump ore arriving at the factory is added from the top of the single roll crusher and cooled in the ring cooler together with the sintered ore. The lump ore is dried during the cooling process and the crystal water is removed. The cooled sintered ore and lump ore are sent to the screening device for screening, and those with a diameter of +5mm are sent to the blast furnace for smelting; 2) Adjust the blast furnace charging plan, reduce the ore charging angle by 1°-3°, expand the edge gas effect, and increase the degree of reduction in the ore angle as the lump ore ratio increases, thus completing the intensified blast furnace smelting under high lump ore ratio.

2. The method for intensified blast furnace smelting under high lump ore ratio according to claim 1, characterized in that: In the step 1), the waste heat generated by the sintered ore is used to dry and screen the lump ore.

3. The method for intensified blast furnace smelting under high lump ore ratio according to claim 1, characterized in that: The cooling time in step 1) is 30 min-90 min.

4. The method for intensified blast furnace smelting under high lump ore ratio according to claim 1, characterized in that: After cooling in step 1), the temperature of the sintered ore and lump ore is lower than 150°C.

5. The method for intensified blast furnace smelting under high lump ore ratio according to claim 1, characterized in that: In the step 2), the total proportion of blast furnace lump ore added is 25%-40%.