Sintering method for matching high alkali metal magnetite with high titano-magnetite

Abstract

The invention provides a sintering method for matching high alkali metal magnetite with high titano-magnetite, which is characterized by comprising the following steps: (1) preparing limonite, high alkali metal magnetite concentrate, high titano-magnetite, secondary resources, limestone powder, dolomite powder, quicklime powder, coke powder and coke ash in proportion, and sequentially carrying out herringbone stacking by using a stacker-reclaimer; (2) carrying out stepped material taking by using a stacker-reclaimer; (3) feeding into a primary mixer, adding sludge water with the concentration of 25-35% and the temperature of 50-90 DEG C, and mixing; (4) feeding into a secondary mixer, introducing steam, and heating to 40-55 DEG C; (5) steam is introduced into the ore feeding groove to heat the ore feeding groove to 55-70 DEG C; (6) uniformly spreading the raw materials on a sintering machine according to the blanking amount of 260-310t / h; and (7) sintering is completed under the conditions that the ignition temperature is 1080-1150 DEG C, the operation speed of a sintering machine is 0.95-1.20 m / min, the final temperature is 390-440 DEG C, the flue temperature is 120-150 DEG C, and the negative pressure is 13-15.0 kpa.

Description

Technical Field

[0001] The present invention relates to a sintering method, in particular to a sintering method for high-alkali metal magnetite combined with high-titanium magnetite, which is applied to the technical field of smelting raw material preparation. Background Art

[0002] Magnetite, as a natural ore, widely exists in the earth's crust. Its chemical composition is Fe 3 O 4 , which is a complex oxide containing high-valent iron and low-valent iron. Generally, the iron content ratio in magnetite is as high as 72.4%, and this high proportion of iron content makes magnetite the main raw material in the iron-making process.

[0003] Sintered ore refers to the massive sintered ore obtained after mixing iron ore powder with coke powder as fuel and CaO or / and MgO powder as binder, and then sending it to a sintering machine for drying and high-temperature sintering treatment. This sintering process can bond the iron ore powder together to form a block. Through sintering, the iron content of the iron ore powder can be increased, and at the same time, the iron ore powder that cannot directly enter the blast furnace can be sintered into blocks, which is beneficial to blast furnace smelting and effectively utilizes the valuable iron ore powder resources. However, the sintering process will also have a certain impact on the sintering performance and bonding degree of iron ore. This is because: on the one hand, due to the differences in the properties of different iron ores, ore structure changes and chemical reactions will occur during the sintering process, making some iron ores unable to achieve the expected effect; on the other hand, the bonding degree and sintering performance of iron ore used for sintering vary in different environments, which will also affect the transportation and smelting effects of sintered ore.

[0004] Currently, the proportion of -200 mesh magnetite powder selected for sintering is generally above 90%. Since the surface of -200 mesh magnetite powder is smooth, there will be a problem of low pelletizing rate of the mixture during pelletizing in the mixer. This will lead to poor permeability of the material layer when the material is distributed on the sintering machine and ignited and sucked for sintering, and the negative pressure of the flue gas main pipe will rise, severely restricting the production capacity and quality of the sintering machine. In addition, the fuel consumption is relatively large at 56.18 kg / t. Among the sintered ore indicators, the sintered ore with a particle size of 16 - 40 mm only accounts for 54.4%, the drum index is 75.5%, TFe ± 0.8%, and R ± 0.12, resulting in high ore blending costs. Therefore, it is necessary to improve the existing technology. Summary of the Invention

[0005] In order to solve the problems in the existing magnetite sintering, such as low pelletizing efficiency of the mixture, poor permeability of the material layer, rising negative pressure of the flue gas main pipe, too high ore blending cost, and poor quality of sintered ore, the present invention provides a sintering method for high-alkali metal magnetite combined with high-titanium magnetite.

[0006] The present invention is accomplished by the following technical solutions: A sintering method for high-alkali metal magnetite combined with high-titanium magnetite, comprising the following steps: (1) Prepare materials such as limonite, high-alkali metal magnetite concentrate, high-titanium magnetite, secondary resources, limestone powder, dolomite powder, quicklime powder, coke powder, and coke ash in proportion, and use a stacker-reclaimer to carry out herringbone stacking in sequence to stabilize the chemical components of each material; (2) Use a stacker-reclaimer to take the stacked materials in step (1) in a stepped manner from high to low, control the height of the taking section to be 1 m and the width of the taking section to be 1.2 - 1.6 m, send the obtained materials to the secondary stockyard, and use a stacker-reclaimer to carry out secondary stacking, control the secondary stacking angle to be 40 - 55°, and the number of layers of each stockpile to be 580 - 620 layers, control the basicity R = 1.2 - 1.6, TFe = 52 ± 0.6%, to obtain a mixed material; (3) Send the mixed ore in step (2) to a primary mixer, add sludge water with a mass concentration of 25 - 35% and a temperature of 50 - 90 °C to fully moisten the mixed material, and obtain a primary mixed material with uniform moisture, particle size, and chemical components; (4) Send the primary mixed material in step (3) to a secondary mixer, heat it to 40 - 55 °C by introducing steam, control the basicity R = 1.6 - 1.85, moisture 7.0 - 7.5%, and fixed carbon 3.0 - 3.6%, to obtain a secondary mixed material; (5) Send the secondary mixed material in step (4) to an ore bin, heat it to 55 - 70 °C by introducing steam, to obtain a preheated mixed material; (6) Feed the preheated mixed material in step (5) at a feeding rate of 260 - 310 t / h through a disk feeder with a round roller speed of 200 - 400 revolutions per minute and a nine-roller speed of 400 - 1200 revolutions per minute, and evenly spread it on the sintering machine, control the thickness of the material layer to be 700 mm - 800 mm; (7) Carry out sintering under the conditions of an ignition temperature of 1080 - 1150 °C, a sintering machine running speed of 0.95 - 1.20 m / min, an end temperature of 390 - 440 °C, a sintering machine end position of 16.4 - 17.0, a flue gas temperature of 120 - 150 °C, and a negative pressure of 13 - 15.0 kPa, to obtain sintered ore.

[0007] Further, the raw materials in step (1) are prepared according to the following mass ratios: Imported ore 10 - 35%, High-alkali metal magnetite concentrate 25 - 40%, High-titanium magnetite 5 - 11%, Secondary resources 20 - 22%, Limestone powder 5 - 10%, Dolomite powder 3 - 6%, Quicklime powder 3 - 5%, Coke fines: 3.8 - 4.8%, Coke ash: 0.2 - 0.5%, Total: 100%.

[0008] Furthermore, the secondary resources are prepared according to the following mass percentages: BF return fines: 55 - 65%, Dust removal ash: 8 - 15%, Oxidized slag: 15 - 20%, Steelmaking sludge: 10 - 15%, Total: 100%.

[0009] Furthermore, in the coke fines, the mass ratio of coke fines with a particle size ≤ 3 mm is ≥ 76%; in the coke ash, the mass ratio of coke ash with a particle size ≤ 1 mm is ≥ 90%.

[0010] Furthermore, the sludge water added in step (3) is preheated by steam and then added to the primary mixer.

[0011] The present invention has the following advantages and effects: By adopting the above - mentioned scheme, through reasonable batching ratios, as well as corresponding control of basicity, total iron content, fixed carbon, and moisture of the mixture, and then through corresponding control of the layer thickness, the mixture is evenly spread on the sintering machine. Finally, through the comprehensive control of process conditions such as ignition temperature, sintering machine running speed, end - point temperature, sintering machine end - point position, flue gas temperature, negative pressure, etc., after sintering the high - alkali - metal magnetite with high - titanium magnetite, the quality of the sintered ore is greatly improved, while fuel consumption is reduced, production costs are lowered, and iron ore resources are comprehensively utilized. Specific Embodiments

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will introduce the embodiments in detail. Obviously, for those of ordinary skill in the art, without creative efforts, other embodiments can also be obtained based on these embodiments.

[0013] The chemical compositions of the ores used in the present invention are as follows in the table: Example 1

[0014] A sintering method for high - alkali - metal magnetite with high - titanium magnetite, comprising the following steps: (1) 25% of imported ore, 31% of high - alkali - metal magnetite concentrate, 5% of high - titanium magnetite, 20% of secondary resources, 5.2% of limestone powder, 4.3% of dolomite powder, 5.0% of quicklime powder, 4.0% of coke fines, and 0.5% of coke ash are stacked in a herringbone pattern in sequence by a stacker - reclaimer to stabilize the chemical compositions of each material; Among them: 20% of the secondary resources are raw materials with the following mass ratios: 65% of sinter return fines, 8% of dedusting ash, 17% of oxidized slag, and 10% of steelmaking sludge; Among the coke fines, the mass ratio of coke fines with a particle size ≤ 3 mm is ≥ 76%; Among the coke ash, the mass ratio of coke ash with a particle size ≤ 1 mm is ≥ 90%; (2) Use a stacker-reclaimer to take the stacked materials in a stepped manner from high to low, control the height of the take-off section to be 1 m and the width of the take-off section to be 1.2 m, send the obtained materials to the secondary stockyard, and use a stacker-reclaimer for secondary stacking, control the secondary stacking angle to be 55°, and the number of layers of each stockpile to be 620 layers, control the basicity R = 1.32 and TFe = 52.66% to obtain a mixed material; (3) Send the mixed ore in step (2) into a primary mixer, add sludge water with a mass concentration of 35% and a temperature of 50 °C to fully moisten the mixed ore, and obtain a primary mixed material with uniform moisture, particle size, and chemical composition; (4) Send the primary mixed material in step (3) into a secondary mixer, heat it to 45 °C by passing steam, control the basicity R = 1.6, moisture 6.8%, and fixed carbon 3.30% to obtain a secondary mixed material; (5) Send the secondary mixed material in step (4) into a ore bin, heat it to 55 °C by passing steam to obtain a preheated mixed material; (6) Feed the preheated mixed material in step (5) onto the sintering machine at a feeding rate of 280 t / h through a disk feeder with a round roller speed of 200 revolutions per minute and a nine-roller speed of 1200 revolutions per minute, and control the thickness of the material layer to be 700 mm; (7) Carry out sintering under the conditions of an ignition temperature of 1080 °C, a sintering machine running speed of 0.95 m / min, a sintering end temperature of 390 °C, a sintering machine end position of 16.4, a flue gas temperature of 120 °C, and a negative pressure of 13 kPa to obtain sintered ore.

[0015] The quality indexes of the sintered ore: Sintered ore with a particle size of 16 - 40 mm accounts for 70.4%, the drum index is 80.5%, TFe ± 0.5%, R ± 0.06, the stacking amount of the mixed ore is 96,000 tons, the unit price of high-titanium magnetite is 390 yuan per ton lower than that of high-alkali metal magnetite, and the cost is reduced by 1.87 million yuan. Example 2

[0016] A sintering method for high-alkali metal magnetite mixed with high-titanium magnetite, comprising the following steps: (1) Stack 19% of imported ore, 35% of high-alkali metal magnetite concentrate, 11% of high-titanium magnetite, 15% of secondary resources, 7.3% of limestone powder, 4.5% of dolomite powder, 3.7% of quicklime powder, 4.2% of coke fines, and 0.3% of coke ash in a herringbone pattern in sequence using a stacker-reclaimer to stabilize the chemical composition of each material; Among them: 15% of the secondary resources are raw materials with the following mass ratios: 61% of sinter return fines, 12% of dedusting ash, 19% of oxidized slag, and 8% of steelmaking sludge; Among the coke fines, the mass ratio of coke fines with a particle size ≤ 3 mm is ≥ 76%; Among the coke ash, the mass ratio of coke ash with a particle size ≤ 1 mm is ≥ 90%; (2) Use a stacker-reclaimer to take the stacked materials in a stepped manner from high to low, control the height of the material-taking section to be 1 m and the width of the material-taking section to be 1.2 m, send the obtained materials to the secondary stockyard, and perform secondary stacking with a stacker-reclaimer, control the secondary stacking angle to be 50°, and the number of layers of each stockpile is 600 layers, control the basicity R = 1.51 and TFe = 51.58% to obtain a mixed material; (3) Send the mixed ore in step (2) into a primary mixer, add sludge water with a mass concentration of 25% and a temperature of 45°C to fully moisten the mixed ore, and obtain a primary mixed material with uniform moisture, particle size, and chemical composition; (4) Send the primary mixed material in step (3) into a secondary mixer, heat it to 45°C by introducing steam, control the basicity R = 1.63, moisture 7.2%, and fixed carbon 3.54% to obtain a secondary mixed material; (5) Send the secondary mixed material in step (4) into a ore bin, heat it to 55°C by introducing steam to obtain a preheated mixed material; (6) Feed the preheated mixed material in step (5) at a feeding rate of 260 t / h through a disk feeder with a round roller speed of 200 revolutions per minute and a nine-roller speed of 1000 revolutions per minute, and evenly spread it on the sintering machine, control the thickness of the material layer to be 750 mm; (7) Conduct sintering under the conditions of an ignition temperature of 1080°C, a sintering machine running speed of 0.98 m / min, a sintering end temperature of 398°C, a sintering machine end position of 16.4, a flue gas temperature of 130°C, and a negative pressure of 14.8 kPa to obtain sintered ore.

[0017] The quality indexes of the sintered ore: The sintered ore with a particle size of 16 - 40 mm accounts for 71.1%, the drum index is 80.8%, TFe ± 0.5%, R ± 0.08, the stacking amount of the blended ore is 96,000 tons, the unit price of high-titanium magnetite is 390 yuan per ton lower than that of high-alkali-metal magnetite, and the cost is reduced by 4.12 million yuan. Example 3

[0018] A sintering method for high-alkali-metal magnetite mixed with high-titanium magnetite, comprising the following steps: (1) Take 20% of imported ore, 36% of high-alkali metal magnetite concentrate, 10% of high-titanium magnetite, 15% of secondary resources, 7% of limestone powder, 4.2% of dolomite powder, 3.4% of quicklime powder, 4.2% of coke powder, and 0.2% of coke ash, and use a stacker-reclaimer to conduct herringbone stacking in sequence to stabilize the chemical composition of each material; Among them: 15% of the secondary resources are raw materials with the following mass ratios: 65% of sinter return ore, 10% of dust removal ash, 15% of oxidized slag, and 10% of steelmaking sludge; Among the coke powder, the mass ratio of coke powder with a particle size ≤ 3 mm is ≥ 76%; Among the coke ash, the mass ratio of coke ash with a particle size ≤ 1 mm is ≥ 90%; (2) Use a stacker-reclaimer to take the stacked material in step (1) from high to low in a stepped manner, control the height of the take-off section to be 1 m and the width of the take-off section to be 1.2 m, send the obtained material to the secondary stockyard, and use a stacker-reclaimer to conduct secondary stacking, control the secondary stacking angle to be 45°, and the number of layers of each stockpile to be 580 layers, control the basicity R = 1.44, TFe = 52.35%, and obtain a mixed material; (3) Send the mixed ore in step (2) into a primary mixer, add sludge water with a mass concentration of 28% and a temperature of 47 °C to fully wet the mixed ore, and obtain a primary mixed material with uniform moisture, particle size, and chemical composition; (4) Send the primary mixed material in step (3) into a secondary mixer, heat it to 45 °C by passing steam, control the basicity R = 1.74, moisture 7.0%, and fixed carbon 3.52%, and obtain a secondary mixed material; (5) Send the secondary mixed material in step (4) into a ore bin, heat it to 55 °C by passing steam, and obtain a preheated mixed material; (6) Feed the preheated mixed material in step (5) at a feeding rate of 280 t / h through a disk feeder with a round roller speed of 200 revolutions / min and a nine-roller speed of 800 revolutions / min, and evenly spread it on the sintering machine, controlling the thickness of the material layer to be 800 mm; (7) Conduct sintering under the conditions of an ignition temperature of 1150 °C, a sintering machine running speed of 1.2 m / min, a sintering end temperature of 440 °C, a sintering machine end position of 17.0, a flue gas temperature of 150 °C, and a negative pressure of 15 kPa to obtain sintered ore.

[0019] The quality indexes of the sintered ore: Sintered ore with a particle size of 16 - 40 mm accounts for 70.2%, the drum index is 79.3%, TFe ± 0.5%, R ± 0.08, the stacking amount of the homogenized ore is 96,000 tons, the unit price of high-titanium magnetite is 390 yuan / ton lower than that of high-alkali metal magnetite, and the cost is expected to be reduced by 3.74 million yuan. Example 4

[0020] A sintering method for high-alkali metal magnetite with the addition of high-titanium magnetite, comprising the following steps: (1) Take 25% of imported ore, 31% of high-alkali metal magnetite concentrate, 10% of high-titanium magnetite, 15.5% of secondary resources, 5.5% of limestone powder, 4% of dolomite powder, 4.4% of quicklime powder, 4.2% of coke powder, and 0.4% of coke ash, and use a stacker-reclaimer to carry out chevron stacking in sequence to stabilize the chemical composition of each material; Among them, 15.5% of the secondary resources are raw materials with the following mass ratios: 57% of sinter return fines, 8% of dedusting ash, 20% of oxidized slag, and 15% of steelmaking sludge; Among the coke powder, the mass ratio of coke powder with a particle size ≤ 3 mm is ≥ 76%; Among the coke ash, the mass ratio of coke ash with a particle size ≤ 1 mm is ≥ 90%; (2) Use a stacker-reclaimer to take the stacked material in step (1) from high to low in a stepped manner, control the height of the take-off section to be 1 m and the width of the take-off section to be 1.6 m, send the obtained material to the secondary stockyard, and use a stacker-reclaimer to carry out secondary stacking, control the secondary stacking angle to be 52°, and the number of layers of each stockpile to be 590 layers, control the basicity R = 1.54, TFe = 52.55% to obtain a mixed material; (3) Send the mixed ore in step (2) into a primary mixer, add sludge water with a mass concentration of 32% and a temperature of 50 °C to fully moisten the mixed ore to obtain a primary mixed material with uniform moisture, particle size, and chemical composition; (4) Send the primary mixed material in step (3) into a secondary mixer, heat it to 55 °C by passing steam, control the basicity R = 1.84, moisture 7.5%, and fixed carbon 3.12% to obtain a secondary mixed material; (5) Send the secondary mixed material in step (4) into a ore bin, heat it to 55 °C by passing steam to obtain a preheated mixed material; (6) Feed the preheated mixed material in step (5) at a feeding rate of 300 t / h through a disk feeder with a round roller speed of 400 revolutions per minute and a nine-roller speed of 900 revolutions per minute, and evenly spread it on the sintering machine, control the thickness of the material layer to be 700 mm; (7) Carry out sintering under the conditions of an ignition temperature of 1090 °C, a sintering machine running speed of 1.0 m / min, a sintering end temperature of 420 °C, a sintering machine end position of 16.5, a flue gas temperature of 130 °C, and a negative pressure of 13 kPa to obtain sintered ore.

[0021] The quality indexes of the sintered ore are as follows: The sintered ore with a particle size of 16 - 40 mm accounts for 70.15%, the drum index is 79.63%, TFe ± 0.5%, R ± 0.08, the stacking quantity of the blended ore is 96,000 tons, the unit price of high-titanium magnetite is 390 yuan / ton lower than that of high-alkali metal magnetite, and the cost reduction is expected to be 3.72 million yuan.

[0022] In the above-mentioned Embodiments 1-4, the sludge water added in step (4) is added to the mixer after continuously heating the sludge pool by introducing the steam from steelmaking and rolling.

[0023] The present invention is conducive to the high-proportion use of magnetite, reduces the fuel consumption by about 6 kg / t, improves the indexes of sintered ore, and well reduces the production cost.

[0024] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0025] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and the description in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A sintering method of high alkali metal magnetite with high titanium magnetite, characterized in that The following steps are involved: (1) Prepare limonite, high alkali metal magnetite concentrate, high titanium magnetite, secondary resources, limestone powder, dolomite powder, quicklime powder, coke powder and coke ash in proportion and stack them in a herringbone shape in sequence using a stacker-reclaimer to stabilize the chemical composition of each material; (2) The piled materials in step (1) are taken from high to low by a stacker-reclaimer, and the height of the reclaiming section is controlled to be 1 m, and the width of the reclaiming section is controlled to be 1.2-1.6 m. The taken materials are sent to a secondary material yard, and a stacker-reclaimer is used for secondary stacking, and the secondary stacking angle is controlled to be 40-55°, and the number of layers of each material pile is 580-620 layers, and the alkalinity R is controlled to be 1.2-1.6, and TFe is controlled to be 52±0.6%, to obtain a mixed material; (3) The mixed ore from step (2) is sent to a primary mixer, and sludge water with a mass concentration of 25-35% and a temperature of 50-90°C is added to fully wet the mixed material to obtain a primary mixed material with uniform moisture, particle size and chemical composition; (4) sending the primary mixture of step (3) to a secondary mixer, introducing steam to heat to 40-55° C., controlling the alkalinity R=1.6-1.85, the moisture content 7.0-7.5%, and the fixed carbon content 3.0-3.6%, to obtain a secondary mixture; (5) The secondary mixture of step (4) is sent to a ore tank and heated to 55-70° C. by steam to obtain a preheated mixture; (6) The preheated mixed material of step (5) is fed at a rate of 260-310 t / h, and is evenly spread on the sintering machine through a disc distributor with a round roller speed of 200-400 rpm and a nine-roller speed of 400-1200 rpm, and the material layer thickness is controlled to be 700 mm-800 mm; (7) Sintering is carried out under the conditions of ignition temperature of 1080-1150°C, sintering machine running speed of 0.95-1.20 m / min, end point temperature of 390-440°C, sintering machine end point position of 16.4-17.0, flue temperature of 120-150°C, and negative pressure of 13-15.0 kPa to obtain sintered ore.

2. The sintering method of high alkali metal magnetite with high titanium magnetite according to claim 1, characterized in that The raw materials in step (1) are prepared according to the following mass ratio: Imported ore 10-35%, High alkali metal magnetite concentrate 25-40%, High titanium magnetite 5-11%, Secondary resources 20-22%, Limestone powder 5-10%, Dolomite powder 3-6%, Quicklime powder 3-5%, Coke powder 3.8~4.8%, Coke ash 0.2~0.5%, The total is 100%.

3. The sintering method of high alkali metal magnetite with high titanium magnetite according to claim 1, characterized in that The secondary resources are prepared according to the following mass percentages: Blast furnace return ore 55-65%, Dust removal 8-15%, Oxidation slag 15-20%, Steelmaking sludge 10-15%, The total is 100%.

4. The sintering method of high alkali metal magnetite with high titanium magnetite according to claim 1, characterized in that In the coke powder, the mass ratio of coke powder with a particle size of ≤3 mm is ≥76%; in the coke ash, the mass ratio of coke ash with a particle size of ≤1 mm is ≥90%.

5. The sintering method of high alkali metal magnetite with high titanium magnetite according to claim 1, characterized in that The sludge water added in step (3) is preheated by steam and then added to the primary mixer.

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