Method for sintering ultrahigh material layer

Abstract

The invention provides a method for realizing ultrahigh material layer sintering, which is applied to the field of sintering pellets in the metallurgical industry. The method comprises the following specific steps: preparing a sintering mixture consisting of an iron-containing raw material, coke powder / coal powder, high-calcium high-activity quick lime and the like, and spraying hot water in a primary mixer to uniformly digest the lime; conveying the mixture to a secondary mixer for reinforced granulation; blowing high-temperature steam to the mixing bin of the sintering machine to increase the temperature of the material; sintering ore is laid at the bottom of the sintering machine trolley as a grate-layer material; paving the mixture onto a sintering trolley to form an ultrahigh material layer; and finally, igniting and combusting to obtain the required sintered ore. The problems that the air permeability of a material layer becomes poor, the quality of sintered minerals is reduced and the like are solved, the mass fraction, the yield and the utilization coefficient of calcium ferrite are remarkably improved, meanwhile, solid fuel consumption is reduced, and efficient and low-consumption sintering production is achieved. The method is suitable for various sintering machines, and is particularly suitable for technical transformation and upgrading of old sintering machines.

Description

Technical Field

[0001] The invention belongs to the field of sintering pellets in the metallurgical industry, and in particular relates to a method for realizing ultra-high material layer sintering. Background Art

[0002] The charge structure of blast furnace ironmaking in my country is mainly sintered ore, and the average proportion of sintered ore entering the furnace is more than 70%. However, the sintering process generally has problems such as high process energy consumption, large emissions of flue gas and pollutants. In view of this, the State Environmental Protection Administration clearly pointed out in the environmental impact assessment requirements for the steel development plan that "the sintering process reduces energy consumption and pollutant emissions. Under the increasingly stringent environmental protection requirements, the production capacity under the normal sintering material layer is indeed difficult to meet the blast furnace's demand for sintered ore quality. This challenge mainly stems from the impact of the improvement of environmental protection requirements on the sintering production process, and the high standards of blast furnaces for the quality of sintered ore. In order to meet this challenge, a series of measures need to be taken to optimize the production process to ensure the quality of sintered ore while meeting environmental protection requirements.

[0003] First, through technological innovation and process improvement, such as the application of high wind temperature technology, the thermal efficiency of the sintering process can be improved, thereby improving production efficiency while ensuring quality. In addition, optimizing ore blending and adjusting sintering process parameters are also key measures to improve the quality of sintered ore. For example, by adjusting the use of sintering flux, the metallurgical properties of sintered ore can be improved, its strength and reducibility can be improved, and the needs of blast furnace smelting can be met. Thick layer sintering increases the thickness of the sintering layer and utilizes the automatic heat storage capacity of the layer to improve energy utilization efficiency and reduce sintering solid fuel consumption. At the same time, the heat storage capacity of the sintering process is improved, the quality of sintered ore is improved, the yield rate is increased, the process energy consumption is reduced, and the emission of environmental pollutants is reduced, realizing an efficient and low-consumption production method.

[0004] Thick layer sintering technology is an advanced sintering technology, which is based on calcium ferrite consolidation theory and automatic heat storage. At present, sintering machines are actively promoting thick layer sintering. Through renovation and overhaul, the baffle of the sintering machine trolley is raised, the material height is self-measured by radar, and the material distribution equipment is changed to eleven rollers, in which each roller is set at a different speed to promote segregation material distribution. The sintering machines all use hot air sintering, and a powerful mixer is added to the mixing system, and three mixing and strengthening granulation. Although a series of measures have been taken, as the material layer increases, the negative pressure of the sintering main pipe increases, and the over-wet zone thickens significantly. The main reason is that the particle size of the mixture has not reached the best, the sintering machine speed is fast, and the air permeability of the material layer is still poor. For old sintering machines, air leakage also limits the improvement of the sintering material layer. Summary of the invention

[0005] In view of the shortcomings in the prior art: the thickness of the sintering machine cloth increases, the air permeability of the material layer deteriorates, the over-wet zone becomes wider, the quality of the sintered ore decreases, etc., the purpose of the present invention is to provide a method that can improve the granulation effect of the mixed material, increase the air permeability of the material layer, and achieve ultra-high material layer sintering of more than 950mm.

[0006] To achieve the above object, the present invention is implemented by the following technical solutions:

[0007] A method for realizing ultra-high material layer sintering comprises the following steps:

[0008] Step 1, preparing a sintering mixture: the sintering mixture is composed of one or more combinations of iron-containing raw materials, coke powder and / or coal powder as fuel, high-calcium and high-activity quicklime, limestone and dolomite as flux; after preparation, each component is transported to a primary mixer according to the designed ratio;

[0009] Among them, high calcium and high activity quicklime is fully digested at the inlet of the primary mixer and then added to other mixed materials at the inlet of the primary mixer, and hot water is sprayed in the primary mixer to make the digested lime and other mixed materials evenly mixed;

[0010] Step 2, conveying the mixed material in step 1 to a secondary mixer, adding a fuel accounting for a certain proportion of the mixed material into the mixed material at the inlet of the secondary mixer, mixing and strengthening granulation to form a sintered mixed material;

[0011] Step 3, conveying the sintering mixture in step 2 to the mixing bin of the sintering machine, and spraying high-temperature steam into the mixing bin to increase the temperature of the sintering mixture;

[0012] Step 4: laying sintered ore on the bottom of the sintering machine trolley as a base material;

[0013] Step 5: Spread the sintering mixture in step 3 onto the sintering trolley so that the thickness of the sintering material layer reaches more than 950 mm;

[0014] Step six, ignite and burn the surface of the material layer on the trolley to obtain the required sintered ore.

[0015] As a further optimization scheme of the present invention, the iron-containing raw material includes mixed ore and returned ore, and the mixed ore includes one or more combinations of Ka powder, A powder, Mike powder, King powder, mixed powder, high silicon powder, iron dust mud, and homogeneous material.

[0016] As a further optimization scheme of the present invention, in step one, a quicklime bin and a matching digestion device are set at the inlet of the primary mixer, and the active quicklime with an activity greater than 300 ml and a CaO content greater than 85% is fully digested at the inlet of the primary mixer and then added to the mixed material at the inlet of the primary mixer, and the temperature of the hot water sprayed on the primary mixer is above 80°C.

[0017] As a further optimization scheme of the present invention, in step 2, a fuel adding device is provided at the second mixing inlet, and the fuel added to the mixture accounts for 0.7-1% of the total mass of the mixture.

[0018] As a further optimization scheme of the present invention, in step three, steam above 200° C. is sprayed into the mixed material bin to increase the temperature of the sintering mixed material to above 70° C.

[0019] As a further optimization scheme of the present invention, in step 4, sintered ore with a thickness of 50-60 mm and a particle size of 10-16 mm is laid on the bottom of the sintering machine trolley as a base material.

[0020] As a further optimization scheme of the present invention, in step five, during the distribution of the mixture, the mixture passes through three layers of upward jet-jet loosening rods and is then distributed to the trolley to achieve suspended distribution.

[0021] As a further optimization scheme of the present invention, in step six, the ignition time is 60 to 90 seconds, the ignition negative pressure is -15 to 5 kpa, the sintering main pipe negative pressure is 16 to 17 kpa, and the machine speed is controlled at 2.0 to 2.5 m / min.

[0022] Compared with the prior art, the present invention has the following significant advantages and beneficial effects:

[0023] The method for realizing ultra-high material layer sintering provided by the present invention uses iron ore powder as the main raw material, coke powder and coal powder as fuel, and high-calcium active quicklime, limestone, and dolomite as flux to realize ultra-high material layer sintering of the sintering machine. The problem that the material layer of the sintering machine is increased, the air permeability of the material layer is deteriorated, and the quality of the sintering machine is affected is solved. The method can improve the economic and technical indicators of sintering, increase the mass fraction of calcium ferrite by more than 3%, increase the yield by more than 2%, and increase the utilization coefficient to 1.36t / m 2 ·h -1 , solid fuel consumption is reduced by more than 2Kg / t, the output and quality of sintered ore are improved, and energy consumption is reduced. DETAILED DESCRIPTION

[0024] The following describes specific embodiments, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are used to illustrate the present invention, rather than to limit the present invention.

[0025] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs, and if there is a conflict, this specification takes precedence.

[0026] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market.

[0027] The present invention discloses a method for realizing ultra-high material layer sintering, wherein the material layer uses iron-containing raw materials as main raw materials, coke powder and coal powder as fuels, and high-calcium and high-activity quicklime, limestone, and dolomite as fluxes to realize ultra-high material layer sintering of more than 950 mm, comprising the following steps:

[0028] (1) The iron-containing raw materials, fuel and flux from the batching room are transported to the primary mixer according to the raw material ratio set according to the quality requirements of the sintered ore. The primary mixer is equipped with a ash bin, a belt scale and a digester. The active quicklime with an activity of more than 300 ml and a CaO content of more than 85% is transported to the ash bin by an airtight tank truck. After being discharged according to the set amount, it is digested and added to the mixed material at the inlet of the primary mixer. Hot water above 80°C is sprayed into the primary mixer. After digestion, the raw ash and the mixed material are mixed more evenly and the granulation effect is better. The moisture content of the mixed material is set to 7.2±0.4%. The iron-containing raw materials are mainly mixed ore including different combinations of Ka powder, A powder, Mike powder, King powder, mixed powder, high silicon powder, iron dust mud, homogenized material, sintering return ore, etc.

[0029] (2) The mixed material is conveyed to the secondary mixer via a belt for mixing and strengthening granulation. A fuel bin and a dosing device are provided at the secondary mixing inlet, and 0.7 to 1% of the mixed material is added to the secondary mixing inlet for mixing and granulation to form a sintering mixed material.

[0030] (3) The mixed material output from the secondary mixer is transported to the mixed material bin of the sintering machine, and steam above 200°C is sprayed into the mixed material bin to increase the temperature of the sintered mixed material to above 70°C.

[0031] (4) The bottom of the sintering machine trolley is paved with sintered ore with a thickness of 50-60 mm and a particle size of 10-16 mm as the base material.

[0032] (5) The sintering mixture is spread onto the sintering trolley. During the spreading process, the mixture is arranged in three layers in the vertical direction and the loosening rods are blown upward by air, and then spread onto the trolley. Due to the gas blowing force, the mixture is spread in a suspended manner, and the thickness of the sintering material layer reaches more than 950 mm.

[0033] (6) The surface of the material layer on the trolley is then ignited and burned, and parameters such as appropriate negative pressure, machine speed and sintering end point are controlled to obtain sintered ore that meets the requirements.

[0034] Example 1

[0035] (1) The mixed ore for sintering includes Ka powder, A powder, Mike powder, super special powder, king powder, mixed powder, high silica powder, iron dust mud, and homogenized material, among which Ka powder accounts for 5.6%, Mike powder accounts for 32%, super special powder accounts for 8%, A powder accounts for 6.5%, king powder accounts for 9%, Jia powder accounts for 8%, mixed powder accounts for 12%, high silica powder accounts for 5%, and iron dust mud accounts for 0.6%. The sintering mixed material mainly includes mixed ore, return ore, anthracite powder, limestone, dolomite, and quicklime. Generally, the mixed ore accounts for 61%, the return ore accounts for 25%, the anthracite accounts for 3.3%, the limestone accounts for 4%, the dolomite accounts for 3%, and the quicklime accounts for 1. Ash 3%. The proportion of each raw material is set according to the quality requirements of sintered ore. The iron-containing raw materials, fuel and flux from the batching room are transported to the primary mixer. The primary mixer is inlet to build a raw ash bin, a belt scale and a digester. The active quicklime with an activity greater than 300ml and a CaO content greater than 85% is transported to the raw ash bin by an airtight tank truck. The material is discharged according to the set total ratio of 3% and then digested. It is added to the mixed material at the inlet of the primary mixer, and 85°C hot water is sprayed into the primary mixer. After digestion, the raw ash and the mixed material are mixed more evenly and the granulation effect is better. The primary mixing time is 3.8 minutes, and the moisture content of the mixed material is controlled at 6.8%.

[0036] (2) The mixed material is conveyed to the secondary mixer via a belt for mixing and strengthening granulation. A fuel bin and a dosing device are provided at the secondary mixing inlet. Anthracite powder accounting for 0.7% of the total proportion of the mixed material is added to the mixed material at the secondary mixing inlet by a belt scale. The mixed material is mixed and granulated in the secondary mixer. The secondary mixing and granulation time is 4 minutes.

[0037] (3) The mixed material output from the secondary mixer is transported to the mixed material bin of the sintering machine, and 205°C steam is sprayed into the mixed material bin to increase the temperature of the sintered mixed material to 75°C.

[0038] (4) The bottom of the sintering machine trolley is paved with sintered ore with a thickness of 50 mm and a particle size of 10-16 mm as the base material.

[0039] (5) The sintering mixture is spread onto the sintering trolley. During the spreading process, the mixture is arranged in three layers in the vertical direction and the loosening rods are blown upward by air, and then spread onto the trolley. Due to the gas blowing force, the mixture is spread in a suspended manner, and the thickness of the sintering material layer reaches more than 950 mm.

[0040] (6) Ignite the surface of the material layer on the trolley. The ignition time is 60 seconds. The ignition negative pressure is -15kpa~5kpa. The negative pressure of the sintering main pipe is 16-17kpa. The machine speed is controlled at 2.0m / min-2.5m / min to produce qualified sintered ore.

[0041] By adopting the above technical scheme, qualified sintered ore with the required chemical composition (such as TFe, CaO, SiO2, MgO, Al2O3, S, P, Zn, etc.) can be obtained after sintering to meet the needs of blast furnace production. The main economic and technical indicators and metallurgical properties of the sintered ore when the sintering material layer thickness is 950mm are shown in Table 1.

[0042] Table 1 Main economic and technical indicators

[0043] Solid fuel consumption Power consumption Utilization coefficient <![CDATA[RDI -3.15 ]]> Gas consumption Kg / t kwh / t <![CDATA[t / m 2 ·h -1 ]]> ％ <![CDATA[m 3 / t]]> 46 38 1.365 29 1.9

[0044] Example 2

[0045] (1) The mixed ore for sintering includes Ka powder, A powder, Yangdi powder, Sic concentrate, super special powder, Lei powder, iron dust mud, New powder, and Meijing. The mixed powder is composed of 23% Ka powder, 10% A powder, 46% Yangdi powder, 4% Sic concentrate, 5% super special powder, 4% Lei powder, 2% iron dust mud, 4% New powder, and 2% Meijing. The sintering mixture mainly includes mixed ore, return ore, anthracite powder and limestone, dolomite, and quicklime. The mixture includes 59.0% mixed ore, 25% return ore, 3.8% coal powder, 4.8% limestone, 4.4% dolomite, and 3.0% granular quicklime. The proportion of each raw material is set according to the quality requirements of sintered ore. The iron-containing raw materials, fuel and flux from the batching room are transported to the primary mixer. The primary mixer is inlet with quicklime silo, belt scale and digester. The active quicklime with activity greater than 300ml and CaO content greater than 85% is transported to the quicklime silo by airtight tank truck. The material is discharged according to the set total proportion of 3% and then digested, added to the mixture at the inlet of the primary mixer, and 85°C hot water is sprayed into the primary mixer. After digestion, the quick ash and mixture are mixed more evenly and the granulation effect is better. The primary mixing time is 4 minutes, and the moisture content of the mixture is controlled at 7.0%.

[0046] (2) The mixed material is conveyed to a secondary mixer via a belt for mixing and intensive granulation. A fuel bin and a dosing device are provided at the secondary mixing inlet. Anthracite powder accounting for 0.7% of the total proportion of the mixed material is added to the mixed material at the secondary mixing inlet by a belt scale. The mixed material is mixed and granulated in the secondary mixer. The secondary mixing and granulation time is 4.1 min.

[0047] (3) The mixed material output from the secondary mixer is transported to the mixed material bin of the sintering machine, and 220°C steam is sprayed into the mixed material bin to increase the temperature of the sintered mixed material to 80°C.

[0048] (4) The bottom of the sintering machine trolley is paved with 60mm thick sintered ore with a particle size of 10-16mm as the base material.

[0049] (5) The sintering mixture is spread onto the sintering trolley. During the spreading process, the mixture is arranged in three layers in the vertical direction and the loosening rods are blown upward by air before being spread onto the trolley. Due to the gas blowing force, the mixture is spread in a suspended manner, and the thickness of the sintering material layer reaches more than 970 mm.

[0050] (6) Ignite the surface of the material layer on the trolley, the ignition time is 70 seconds, the ignition negative pressure is -15kpa~5kpa, the sintering main negative pressure is 16-17kpa, the machine speed is controlled at 2.0m / min-2.5m / min, and qualified sintered ore is produced.

[0051] By adopting the above technical scheme, qualified sintered ore with the required chemical composition (such as TFe, CaO, SiO2, MgO, Al2O3, S, P, Zn, etc.) can be obtained after sintering to meet the needs of blast furnace production. The main economic and technical indicators when the sintering material layer thickness is 970 mm are shown in Table 2.

[0052] Table 2 Main economic and technical indicators

[0053]

[0054]

[0055] The above describes the embodiments of the present invention in detail, and the contents described are only some embodiments of the present invention.

[0056] It cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the patent coverage of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for achieving ultra-high material layer sintering, characterized in that: The steps include: Step 1, preparing a sintering mixture: the sintering mixture is composed of one or more combinations of iron-containing raw materials, coke powder and / or coal powder as fuel, high-calcium and high-activity quicklime, limestone and dolomite as flux; after preparation, each component is transported to a primary mixer according to the designed ratio; Among them, high calcium and high activity quicklime is fully digested at the inlet of the primary mixer and then added to other mixed materials at the inlet of the primary mixer, and hot water is sprayed in the primary mixer to make the digested lime and other mixed materials evenly mixed; Step 2, conveying the mixed material in step 1 to a secondary mixer, adding a fuel accounting for a certain proportion of the mixed material into the mixed material at the inlet of the secondary mixer, mixing and strengthening granulation to form a sintered mixed material; Step 3, conveying the sintering mixture in step 2 to the mixing bin of the sintering machine, and spraying high-temperature steam into the mixing bin to increase the temperature of the sintering mixture; Step 4: laying sintered ore on the bottom of the sintering machine trolley as a base material; Step 5: Spread the sintering mixture in step 3 onto the sintering trolley so that the thickness of the sintering material layer reaches more than 950 mm; Step six, ignite and burn the surface of the material layer on the trolley to obtain the required sintered ore.

2. The method for realizing ultra-high material layer sintering according to claim 1, characterized in that: The iron-containing raw materials include mixed ore and returned ore, and the mixed ore includes one or more combinations of Ka powder, A powder, Mike powder, King powder, mixed powder, high silicon powder, iron dust mud, and homogeneous material.

3. The method for realizing ultra-high material layer sintering according to claim 1, characterized in that: In step 1, a quicklime bin and a matching digestion device are set at the inlet of the primary mixer, and the active quicklime with an activity greater than 300 ml and a CaO content greater than 85% is fully digested at the inlet of the primary mixer and then added to the mixed material at the inlet of the primary mixer. The temperature of the hot water sprayed on the primary mixer is above 80°C.

4. The method for realizing ultra-high material layer sintering according to claim 1, characterized in that: In step 2, a fuel adding device is provided at the second mixing inlet, and the fuel added to the mixture accounts for 0.7-1% of the total mass of the mixture.

5. The method for realizing ultra-high material layer sintering according to claim 1, characterized in that: In step three, steam above 200°C is sprayed into the mixed material bin to increase the temperature of the sintered mixed material to above 70°C.

6. The method for realizing ultra-high material layer sintering according to claim 1, characterized in that: In step 4, sintered ore with a thickness of 50-60 mm and a particle size of 10-16 mm is laid on the bottom of the sintering machine trolley as a base material.

7. The method for realizing ultra-high material layer sintering according to claim 1, characterized in that: In step five, during the process of spreading the mixed material, the mixed material passes through three layers of upward jet loosening rods and is then spread onto the trolley to achieve suspended spreading.

8. The method for realizing ultra-high material layer sintering according to claim 1, characterized in that: In step six, the ignition time is 60 to 90 seconds, the ignition negative pressure is -15 to 5 kpa, the sintering main negative pressure is 16 to 17 kpa, and the machine speed is controlled at 2.0 to 2.5 m / min.

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