CN117451567A - Coke reduction performance and mechanical performance measuring method for simulating blast furnace environment - Google Patents
Coke reduction performance and mechanical performance measuring method for simulating blast furnace environment Download PDFInfo
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- 239000000571 coke Substances 0.000 title claims abstract description 164
- 230000009467 reduction Effects 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 27
- 239000000203 mixture Substances 0.000 claims abstract description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000005303 weighing Methods 0.000 claims abstract description 12
- 229910000805 Pig iron Inorganic materials 0.000 claims abstract description 10
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 6
- 238000005070 sampling Methods 0.000 claims abstract description 5
- 238000004364 calculation method Methods 0.000 claims abstract description 3
- 238000012360 testing method Methods 0.000 claims abstract description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 162
- 229910052742 iron Inorganic materials 0.000 claims description 81
- 239000007789 gas Substances 0.000 claims description 26
- 239000000463 material Substances 0.000 claims description 26
- 238000010438 heat treatment Methods 0.000 claims description 25
- 235000019738 Limestone Nutrition 0.000 claims description 21
- 239000006028 limestone Substances 0.000 claims description 21
- 238000004321 preservation Methods 0.000 claims description 18
- 239000012298 atmosphere Substances 0.000 claims description 14
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 230000000630 rising effect Effects 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 239000010439 graphite Substances 0.000 claims description 7
- 229910002804 graphite Inorganic materials 0.000 claims description 7
- 239000002893 slag Substances 0.000 claims description 7
- 238000007873 sieving Methods 0.000 claims description 6
- 230000002159 abnormal effect Effects 0.000 claims description 4
- 238000004380 ashing Methods 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 238000009499 grossing Methods 0.000 claims description 4
- 238000004448 titration Methods 0.000 claims description 4
- 230000009191 jumping Effects 0.000 claims description 3
- 238000012216 screening Methods 0.000 claims description 3
- 238000007493 shaping process Methods 0.000 claims description 3
- 239000008188 pellet Substances 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims 2
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 claims 1
- 238000011534 incubation Methods 0.000 claims 1
- 238000007781 pre-processing Methods 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 abstract description 9
- 238000003723 Smelting Methods 0.000 abstract description 8
- 238000011156 evaluation Methods 0.000 abstract description 5
- 238000006722 reduction reaction Methods 0.000 description 29
- 239000002245 particle Substances 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 230000002378 acidificating effect Effects 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000004876 x-ray fluorescence Methods 0.000 description 3
- STJFYCWYHROASW-UHFFFAOYSA-N Glaudine Chemical compound CN1CCC2=CC(OC)=C(OC)C=C2C2OC(OC)C3=C4OCOC4=CC=C3C12 STJFYCWYHROASW-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 238000005255 carburizing Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 238000002309 gasification Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- UICBCXONCUFSOI-UHFFFAOYSA-N n'-phenylacetohydrazide Chemical compound CC(=O)NNC1=CC=CC=C1 UICBCXONCUFSOI-UHFFFAOYSA-N 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- QMQXDJATSGGYDR-UHFFFAOYSA-N methylidyneiron Chemical compound [C].[Fe] QMQXDJATSGGYDR-UHFFFAOYSA-N 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
- G01N5/04—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/223—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/16—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using titration
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Abstract
The invention relates to a method for measuring the reduction performance and mechanical property of coke in a simulated blast furnace environment, which comprises the steps of sampling and sample pretreatment; determining the composition of the sample; weighing and placing a sample; simulating blast furnace environment treatment, and obtaining a corresponding shrinkage curve and a pressure difference curve; a drip curve; taking out the reduced pig iron, and testing the carbon content of the pig iron; and performing data calculation. The invention provides accurate evaluation for the reduction performance and mechanical strength of the coke in the blast furnace reaction process, so as to solve the problem of coke evaluation distortion, reduce the excessive coke quality, improve the blast furnace smelting coefficient and reduce the coke ratio.
Description
Technical Field
The invention relates to the field of coke performance test, in particular to a method for measuring coke reduction performance and mechanical performance of a simulated blast furnace environment.
Background
Coke is one of the main raw materials in the blast furnace smelting process, and has the most important role in the blast furnace smelting and irreplaceability in supporting the reduction, carburization, heating and skeleton roles of the blast furnace when the blast furnace is stably and smoothly operated. Because the blast furnace is a black box, complicated physical and chemical reactions occur at different parts from top to bottom inside the blast furnace. At the upper part of the furnace body, the furnace burden begins to soften, and the iron-containing furnace burden and upward blast furnace gas undergo a reduction reaction. In the region of 900-1000 deg.C in the middle of furnace body, the carbon-melting reaction is intense, and the iron-containing charge material and coke can produce direct reduction reaction, and at this stage the direct reduction reaction and indirect reduction reaction can be simultaneously used. In the lower hearth area of the blast furnace, direct reduction reaction mainly occurs, and liquid molten iron in the area passes through a dripping belt to enter the hearth; the region is only where the coke can exist stably in solid form, and the skeletal action of the coke in the region is particularly important. The quality of the coke reduction performance and the mechanical performance in the blast furnace also determines whether the blast furnace is running forward or not, and has important influence on the stability, running forward, long service life and the like of the blast furnace. And simultaneously, various economic indexes such as the yield, the coke ratio and the like of the blast furnace are also influenced.
The current cold state strength index of the blast furnace is used for measuring various physicochemical properties of coke, such as M40, M10, ash, volatile matters, granularity and the like at normal temperature. The complex physicochemical reaction occurs in the blast furnace at high temperature, the change of the coke property mainly occurs in the high temperature area of the blast furnace, and the cold state index has great limitation on evaluating the coke quality. The thermal state strength of the conventional coke at present is mainly the reactive CRI and the post-reaction strength CSR, and the condition that the atmosphere of the coke is unchanged and the temperature is unchanged under a certain state is assumed. The coke is in the actual blast furnace internal environment and is the multiphase coupling effect of molten iron, iron oxide, coke, carbon dioxide and steam. The inside of the blast furnace is a high-temperature high-pressure complex environment condition, the coke plays roles of carburizing, reducing, heating and skeleton in the inside, all the characteristics of the coke are that how to reduce iron ore into molten iron better, the influence of the iron ore on the coke is ignored in the previous evaluation, so how to measure the reduction performance and mechanical strength of the coke based on the blast furnace environment is one of the most critical conditions affecting blast furnace smelting, and no suitable method is available at present for measuring the relevant properties of the coke.
Disclosure of Invention
The invention provides a method for measuring the reduction performance and mechanical property of coke in a simulated blast furnace environment, which mainly aims to solve the problem that the influence of the coke on the smelting behavior of iron ore in a blast furnace is unknown, is beneficial to the predicted working condition of blast furnace ironmaking production, and provides a reliable basis for adjusting the operation system in advance. An effective method is established, the actual environment of the blast furnace can be rapidly and accurately simulated, corresponding indexes of the coke reduction performance and the mechanical performance based on the blast furnace environment are provided, and the coke reduction performance and the mechanical performance of the coke based on the blast furnace environment are evaluated.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a method for measuring coke reduction performance and mechanical property of simulated blast furnace environment comprises the following steps:
step one, sampling and sample pretreatment:
1) The coke is crushed, sieved and shaped to obtain a coke sample with the granularity of 10-60 mm and a coke sample with the granularity of 1-10 mm, wherein the coke sample is preferably 15-25 mm. The preferable range of the diced coke sample is 4-6 mm;
2) The pellets, the sintered ore or the natural lump ore are sieved to obtain iron ore samples with the granularity of 10-60 mm, and the iron ore samples are uniformly mixed and divided, preferably 10-15 mm;
3) Limestone with granularity ranging from 1 to 10mm is obtained through crushing and sieving and is used as a slag former, and the granularity range of the limestone sample is preferably 4 to 6mm.
Step two, determining the components of a sample;
carrying out industrial analysis on the coke to obtain ash content of the coke;
1) Ashing the coke to ensure the quality of the ash content of the coke to be more than 6 g;
2) Measuring the element components of the coke ash and the iron ore by using an XRF (X-ray fluorescence spectrometer), and measuring the iron grade of the iron ore by using a titration method;
step three, weighing and placing the sample:
1) Iron ore and coke are mixed according to the mass ratio of 8-1: 2-1, and recording the mass m of the iron ore 1 ；
2) Weighing 2% -5% of diced coke by mass of the iron ore, and uniformly mixing the diced coke and the iron ore;
3) Calculating CaO content and SiO of all the materials (iron ore, coke and coke breeze) 2 The content of the composite material is calculated, and the alkalinity R (the ratio of alkaline oxide to acidic oxide in slag), commonly used m (CaO)/(SiO) 2 ) A representation);
4) Adding limestone into the mixture of iron ore and diced coke to adjust the alkalinity R to be between 1.15 and 1.25;
5) Placing the weighed mixture of coke, iron ore, coke breeze and limestone into a graphite crucible, wherein the coke is arranged below, the mixture of iron ore, coke breeze and limestone is arranged above, and the lower part of the graphite crucible is provided with a porous area, so that molten iron which is heated and melted can drop and be separated from the coke;
6) Paving a layer of coke on the mixture of the iron ore, the diced coke and the limestone, so that the related pressure device is not in direct contact with the iron ore when pressure is applied from top to bottom;
step four, simulating blast furnace environment treatment:
1) Heating the crucible with the materials, and applying a pressure load of 0.01-1 Mpa and an optimal load of 0.1Mpa; recording the initial position of the uppermost part of the material of the crucible by taking the bottommost part of the crucible as a zero point; the ratio of the real-time position of the uppermost part of the material of the crucible to the initial position is multiplied by one hundred percent to obtain a shrinkage curve;
2) Simultaneously recording the pressure difference between the lower part of the crucible material and the upper part of the material in real time when the temperature is raised, namely a pressure difference curve;
3) The molten iron which is heated and melted begins to drip with a corresponding balance for real-time weighing, and the weight curve of the balance is a dripping curve;
4) Heating to 150-250 ℃ in nitrogen atmosphere (the gas flow is 2-10L/min), and the heating rate is 5-20 ℃/min;
5) Heating from 200deg.C to T under nitrogen atmosphere (gas flow rate of 2L/min-15L/min) 1 ，200℃＜T 1 The temperature is less than or equal to 500 ℃, and the heating rate is 10-20 ℃/min; in this interval, the coke does not react with the iron ore and carbon dioxide or water vapor, so a nitrogen atmosphere is adopted;
6) In the mixed atmosphere of 40-60% N according to the volume ratio 2 ，5-35％CO 2 Under the condition of 25-45% CO, 8% -10% water vapor (total gas flow is 2L/min-15L/min) of the mixed gas volume is additionally added, and the mixed gas is heated from T 1 Heating to T 2 The temperature rising rate is 5-20 ℃/min, and the temperature is less than or equal to 1000 ℃ and less than or equal to T 2 ≤1200℃；
7) At T 2 The heat preservation is carried out at the temperature, the heat preservation time is in direct proportion to the temperature rising rate of the step 6) (the heat preservation time is min=A 2 * Heating rate ℃/min+B 2 The best condition is A 2 ＝6，B 2 =0); the treatment of the coke in the step 6) and the step 7) is mainly gasification reaction treatment and is equivalent to a block belt of a blast furnace;
8) According to the volume ratio, the mixed atmosphere is 40 to 60 percent of N 2 ，0-25％CO 2 Under the condition of 25% -55% CO, (the total flow rate of the gas is 2L/min-15L/min), water vapor accounting for 4% -8% of the volume of the mixed gas is additionally added, and the mixed gas is heated from T 2 Temperature to T 3 The temperature rising rate is 5-20 ℃/min, and the temperature is 1200 ℃ less than T 3 ≤1350℃；
9) At T 3 The heat preservation is carried out at the temperature, the heat preservation time is in direct proportion to the temperature rising rate of the step 8) (the heat preservation time is min=A 3 * Heating rate ℃/min+B 3 The best condition is A 3 ＝2,B 3 =20); the treatment of the step 7) and the step 8) on the coke is mainly to simulate the direct reduction and gasification reaction treatment of iron ore and the coke in the blast furnace, which is equivalent to a reflow zone of the blast furnace;
10 In a mixed atmosphere of 40 to 60 percent N according to the volume ratio 2 ，0-25％CO 2 Under the condition of 25% -55% CO (total gas flow is 2L/min-10L/min), adding 0-5% mixed gasFrom T 3 Heating to T 4 The temperature rising rate is between 5 and 20 ℃/min, T 4 ≥1575℃；
11 At T) 4 The heat preservation is carried out at the temperature, the heat preservation time is between 30 and 60 minutes, and the treatment of the step 8) and the step 9) on the coke is mainly to simulate the molten iron dripping process after the reduction of iron ore in the blast furnace and the carburizing process of the coke, which are equivalent to the dripping zone of the blast furnace;
12 Under nitrogen atmosphere (gas flow rate of 2L/min-15L/min), from T 4 Cooling to room temperature along with the furnace;
step five, sample post-treatment:
1) Taking out the reduced non-drip pig iron, and testing the carbon content of the non-drip pig iron;
step six, data calculation:
1) According to the shrinkage curve, the temperature when the shrinkage of the sample reaches 95% is the onset reflow temperature T;
2) According to the shrinkage curve, take the value of T 4 Difference of shrinkage of the sample before and after heat preservation is carried out at the temperature;
3) Smoothing the pressure difference curve to remove jumping abnormal points, taking the temperature corresponding to the maximum value in the pressure difference curve as T Maximum differential pressure If the corresponding peak value of the maximum pressure difference is not greater than 500 ℃ to T 4 The average pressure difference in this section after temperature preservation is more than 0.2kpa, and it is considered that T is absent Maximum differential pressure ；
4) From the drip curve, coke reduction efficiency = drip mass/(iron ore mass m) is calculated 1 * Total iron mass percent).
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a method for measuring the reduction performance and mechanical property of coke in a simulated blast furnace environment, which can measure the reduction performance and mechanical strength of coke based on the blast furnace environment, can measure the influence of the coke on the smelting behavior of the blast furnace, and provides accurate evaluation on the reduction performance and mechanical strength of the coke in the blast furnace reaction process so as to solve the phenomenon of coke evaluation distortion, reduce the phenomenon of excessive coke quality, improve the smelting coefficient of the blast furnace and reduce the coke ratio.
Drawings
FIG. 1 is coke 1 # Original graph (example 1) was determined based on the reduction performance and mechanical properties of the blast furnace environment.
FIG. 2 is coke 2 # Original graph based on reduction performance and mechanical properties of blast furnace environment (example 2).
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the examples of the present invention, and it is apparent that the described embodiments are merely examples and are not intended to limit the present invention.
Example 1:
1. sampling and sample pretreatment
1) Removing representative coke sample (foam coke, furnace end coke, etc.), crushing, sieving and shaping to obtain coke 1 with particle size of 15-25mm # And particle size of 4-6mm as diced 1 # 。
2) Sinter 1 # And (5) obtaining an iron ore sample with the granularity of 10-25mm through sieving, uniformly mixing and dividing.
3) Limestone with the granularity ranging from 4 mm to 6mm is obtained through crushing and screening and is used as a slag former.
2. Sample composition determination
1) Industrial analysis of the coke resulted in ash content of the coke.
2) The coke used is subjected to an ashing after-treatment.
3) The coke ash and the elemental composition of the ore used were measured by XRF (X-ray fluorescence spectrometer), and the iron grade of the iron ore was measured by titration.
3. Sample weighing and placement
1) Iron ore and coke were weighed in a mass ratio of 7.5:2.5, and the iron ore mass was recorded as 300.3g.
2) Weighing 3.3% of the mass of the iron ore, and uniformly mixing the diced coke and the iron ore.
3) Calculate all of the aboveCaO content and SiO content of the Material 2 The content of the composite material is calculated to be 0.96 (the ratio of basic oxide to acidic oxide in slag, commonly used m (CaO)/(SiO) 2 ) Representation).
4) The alkalinity R was adjusted to 1.22 by adding the corresponding limestone to the mixture of iron ore and pyrodine.
5) The weighed coke and the mixture of iron ore, coke breeze and limestone are placed into a graphite crucible, the coke is arranged below, the mixture of iron ore, coke breeze and limestone is arranged above, and the lower part of the graphite crucible is provided with a porous area, so that molten iron melted at a temperature rise can drop and be separated from the coke.
6) The upper layer of the mixture of iron ore, coke and limestone is fully paved with a layer of coke, so that the related pressure devices are not in direct contact with the iron ore when pressure is applied from top to bottom.
4. Simulated blast furnace environmental treatment
1) And heating the crucible with the materials placed, and applying a pressure load of 0.1Mpa. And recording the initial position of the uppermost part of the material of the crucible by taking the bottommost part of the crucible as a zero point. The ratio of the real-time position of the uppermost part of the material of the crucible to the initial position is multiplied by one hundred percent to obtain a shrinkage curve.
2) And simultaneously recording the pressure difference between the lower part of the crucible material and the upper part of the material in real time when the temperature is raised, namely, the pressure difference curve.
3) After molten iron with temperature rise drops, a corresponding balance is used for weighing and recording, and the weight curve of the balance is the dropping curve.
4) The temperature was raised to 200℃under a nitrogen atmosphere (gas flow rate 2L/min) at a temperature-raising rate of 5/min.
5) The temperature was increased from 200℃to 500℃under a nitrogen atmosphere (gas flow rate 2L/min) at a heating rate of 10℃per minute.
6) Under a mixed atmosphere of 20% CO 2 30% CO and 50% N 2 In the following, 9% of water vapor (gas flow 8L/min) was additionally added, and the temperature was raised from 500℃to 1100℃at a rate of 10℃per minute.
7) The temperature is kept at 1100 ℃ for 60min.
8) 15% CO under a mixed atmosphere 2 、35％CO、50％N 2 Under (gas flow rate 8L/min), 6% of water vapor is additionally added, and the temperature is raised from 1100 ℃ to 1300 ℃ at a speed of 5 ℃/min.
9) The temperature is kept at 1300 ℃ for 30min.
10 10% CO under a mixed atmosphere 2 40% CO and 50N 2 At the same time (gas flow rate 8L/min), 3% of water vapor was additionally added, and the temperature was raised from 1300℃to 1600℃at a rate of 5℃per minute.
11 Heat preservation is carried out at 1600 ℃ for 60min.
12 Under nitrogen atmosphere from T) 4 Cooling to room temperature along with the furnace.
5. Sample post-treatment
1) The reduced, already non-drip pig iron was removed and tested for a carbon content of 2.76%.
6. Data computation
1) According to the shrinkage curve, the temperature at which the sample has reached 95% shrinkage is the onset reflow temperature of t= 1268.3 ℃.
2) According to the shrinkage curve, take the value of T 4 The difference between the shrinkage of the samples before and after the heat preservation at the temperature is 2.61 based on the mechanical property index of the blast furnace environment.
3) And smoothing the pressure difference curve to remove abnormal points in the jump. The temperature corresponding to the maximum pressure difference in the pressure difference curve is 1478.4 ℃.
4) From its drip curve, its coke reduction efficiency= 0.663 was calculated.
Example 2:
1. sampling and sample pretreatment
1) Removing representative coke sample (foam coke, furnace end coke, etc.), crushing, sieving and shaping to obtain coke 2 with particle size range of 15-25mm # And particle size of 4-6mm as diced coke 2 # 。
2) The same sintered ore as in example 1 was used, and an iron ore sample having a particle size of 10 to 25mm was obtained by sieving, and the iron ore raw material was obtained by mixing and dividing.
3) Limestone with the granularity ranging from 4 mm to 6mm is obtained through crushing and screening and is used as a slag former.
2. Sample composition determination
1) Industrial analysis of the coke resulted in ash content of the coke.
2) The coke used is subjected to an ashing after-treatment.
3) The coke ash and the elemental composition of the ore used were measured by XRF (X-ray fluorescence spectrometer), and the iron grade of the iron ore was measured by titration.
3. Sample weighing and placement
1) Iron ore and coke were weighed in a mass ratio of 7.5:2.5, and the iron ore mass was recorded as 300.2g.
2) Weighing 3.3% of the mass of the iron ore, and uniformly mixing the diced coke and the iron ore.
3) Calculating CaO content and SiO content of all the materials 2 The content of the composite material is calculated to be 0.98 (the ratio of basic oxide to acidic oxide in slag, commonly used m (CaO)/(SiO) 2 ) Representation).
4) The alkalinity R was adjusted to 1.21 by adding the corresponding limestone to the mixture of iron ore and pyrodine.
5) The weighed coke and the mixture of iron ore, coke breeze and limestone are placed into a graphite crucible, the coke is arranged below, the mixture of iron ore, coke breeze and limestone is arranged above, and the lower part of the graphite crucible is provided with a porous area, so that molten iron melted at a temperature rise can drop and be separated from the coke.
6) The upper layer of the mixture of iron ore, coke and limestone is fully covered with a layer of coke, so that the related pressure device is not in direct contact with the iron ore when pressure is applied from top to bottom.
4. Simulated blast furnace environmental treatment
1) The crucible with the material placed therein was heated, and a pressure load of 0.1Mpa was applied. And recording the initial position of the uppermost part of the material of the crucible by taking the bottommost part of the crucible as a zero point. The ratio of the real-time position of the uppermost part of the material of the crucible to the initial position is multiplied by one hundred percent to obtain a shrinkage curve.
2) And simultaneously recording the pressure difference between the lower part of the crucible material and the upper part of the material in real time when the temperature is raised, namely, the pressure difference curve.
3) After molten iron with temperature rise drops, a corresponding balance is used for weighing and recording, and the weight curve of the balance is the dropping curve.
4) The temperature was raised to 200℃under a nitrogen atmosphere (gas flow rate 2L/min) at a temperature-raising rate of 5/min.
5) The temperature was increased from 200℃to 500℃under a nitrogen atmosphere (gas flow rate 2L/min) at a heating rate of 10℃per minute.
6) Under a mixed atmosphere of 20% CO 2 30% CO and 50% N 2 In the following, 9% of water vapor (gas flow rate 8L/min) was additionally added to raise the temperature from 500℃to 1100℃at a rate of 10℃per minute.
7) The temperature is kept at 1100 ℃ for 60min.
8) 15% CO under a mixed atmosphere 2 、35％CO、50％N 2 Under (gas flow 8L/min), 6% of water vapor is additionally added, and the temperature is raised from 1100 ℃ to 1300 ℃ at a speed of 5 ℃/min.
9) The temperature is kept at 1300 ℃ for 30min.
10 10% CO under a mixed atmosphere 2 40% CO and 50N 2 At the same time (gas flow rate 8L/min), 3% of water vapor was additionally added, and the temperature was raised from 1300℃to 1600℃at a rate of 5℃per minute.
11 Heat preservation is carried out at 1600 ℃ for 60min.
12 Under nitrogen atmosphere from T) 4 Cooling to room temperature along with the furnace.
5. Sample post-treatment
1) The reduced, already non-drip pig iron was removed and tested for a carbon content of 0.76%.
6. Data computation
1) According to its shrinkage profile, the onset reflow temperature at which the sample reached 95% shrinkage was t= 1168.3 ℃.
2) According to the shrinkage curve, take the value of T 4 The difference of the shrinkage of the samples before and after heat preservation at the temperature is 4.35 based on the mechanical property index of the blast furnace environment.
3) Smoothing the pressure difference curve to remove jumping abnormal points, wherein no peak value is greater than 500 ℃ to T 4 After temperature preservation, the average pressure difference of the section is 0.2kpa, and no T exists Maximum differential pressure 。
4) From the drop curve, the coke reduction efficiency was calculated to be 0.298.
As shown in Table 1, examples 1 and 2 are the same iron ore but different cokes, if the properties of both cokes are evaluated to be substantially consistent according to GB/T4000-2017. However, the two cokes were evaluated by the determination method of the present invention to be significantly different, and the coke used in example 1 was significantly better than the coke used in example 2. Example 1 corresponds to a coke having a higher pig iron carbon content than example 2. The coke carburization rate of example 1 is higher than that of example 2. The onset of the reflow temperature T of the coke of example 1 is higher than the onset of the reflow temperature T of the coke of example 2, the coke of example 1 has a corresponding T Maximum differential pressure While example 2 Coke does not correspond to T Maximum differential pressure It was demonstrated that the iron ore melting zone of the example 1 coke was smaller than that of the example 2 coke. The mechanical property index of the example 1 coke is higher than that of the example 2 coke, which indicates that the mechanical property of the example 1 coke based on the blast furnace environment is higher than that of the example 2 coke based on the blast furnace environment. Example 1 coke reduction efficiency was higher than example 2 coke reduction efficiency, indicating that the iron ore reduction rate with example 1 coke was higher than the iron ore reduction rate with example 2 coke. The coke used in example 1 is better than the coke used in example 2 in all its comprehensive indexes, and the coke used in example 1 is better than the coke used in example 2 in its actual production and its blast furnace utilization coefficient. The determination method has good guiding effect on actual production of blast furnace smelting.
Table 1 comparison of case 1 and case 2
| Properties of (C) | Example 1 | Example 2 |
| Carbon content of non-drip pig iron | 2.76％ | 0.76％ |
| T Onset of reflow temperature | 1268.3 | 1168.3℃ |
| Index of mechanical properties | 2.61 | 4.35 |
| Efficiency of coke reduction | 0.663 | 0.298 |
| T Maximum differential pressure | 1478.4℃ | Without any means for |
| GB/T4000-2017 reactivity | 24.2 | 24.1 |
| Post reaction strength of GB/T4000-2017 | 63.7 | 64.6 |
| Coke ratio of blast furnace | 387 | 435 |
| Coefficient of utilization of blast furnace | 2.39 | 1.76 |
。
Claims (10)
1. A method for measuring the reduction performance and mechanical performance of coke in a simulated blast furnace environment is characterized by comprising the following steps:
step one, simulating blast furnace environment treatment:
1) Heating the crucible with the materials, and recording the initial position of the uppermost part of the materials of the crucible by taking the bottommost part of the crucible as a zero point; the ratio of the real-time position of the uppermost part of the material of the crucible to the initial position is multiplied by one hundred percent to obtain a shrinkage curve;
2) Simultaneously recording the pressure difference between the lower part of the crucible material and the upper part of the material in real time when the temperature is raised, namely a pressure difference curve;
3) The molten iron after heating starts to drip for real-time weighing, and the weight curve is the drip curve;
4) Heating to 150-250 ℃ in nitrogen atmosphere, wherein the heating rate is 5-20 ℃/min;
5) Heating from 200 ℃ to T under nitrogen atmosphere 1 ，200℃＜T 1 The temperature is less than or equal to 500 ℃, and the heating rate is 10-20 ℃/min;
6) In the mixed atmosphere of 40-60% N according to the volume ratio 2 ，5-35％CO 2 Adding 8% -10% of water vapor into mixed gas under the condition of 25-45% CO, and heating from T 1 Heating to T 2 The temperature rising rate is 5-20 ℃/min, and the temperature is less than or equal to 1000 ℃ and less than or equal to T 2 ≤1200℃；
7) At T 2 Preserving heat at the temperature, wherein the heat preservation time is in direct proportion to the temperature rising rate of the step 6);
8) According to the volume ratio, the mixed atmosphere is 40 to 60 percent of N 2 ，0-25％CO 2 ，25％-5Adding water vapor with the volume of 4-8% of the mixed gas under the condition of 5% CO, and obtaining the product from T 2 Temperature to T 3 The temperature rising rate is 5-20 ℃/min, and the temperature is 1200 ℃ less than T 3 ≤1350℃；
9) At T 3 Preserving heat at the temperature, wherein the heat preservation time is in direct proportion to the temperature rising rate of the step 8);
10 In a mixed atmosphere of 40 to 60 percent N according to the volume ratio 2 ，0-25％CO 2 Adding 0-5% water vapor into mixed gas under the condition of 25% -55% CO, and heating from T 3 Heating to T 4 The temperature rising rate is between 5 and 20 ℃/min, T 4 ≥1575℃；
11 At T) 4 Preserving heat at the temperature for 30-60 min;
12 Under nitrogen atmosphere from T) 4 Cooling to room temperature along with the furnace;
step two, sample post-treatment:
1) Taking out the reduced pig iron, and testing the carbon content of the pig iron;
step three, data calculation:
1) According to the shrinkage curve, the temperature when the shrinkage of the sample reaches 95% is the onset reflow temperature T;
2) According to the shrinkage curve, take the value of T 4 The difference in shrinkage of the samples before and after incubation was performed at temperature.
3) Smoothing the pressure difference curve to remove jumping abnormal points, taking the temperature corresponding to the maximum value in the pressure difference curve as T Maximum differential pressure If the corresponding peak value of the maximum pressure difference is not greater than 500 ℃ to T 4 The average pressure difference in this section after temperature preservation is more than 0.2kpa, and it is considered that T is absent Maximum differential pressure ；
4) From the drip curve, coke reduction efficiency = drip mass/(iron ore mass m) is calculated 1 * Total iron mass percent).
2. The method for measuring the coke reduction performance and the mechanical performance in the simulated blast furnace environment according to claim 1, wherein the gas flow rate of the nitrogen atmosphere is 2-10L/min.
3. The method for measuring the coke reduction performance and the mechanical performance in the simulated blast furnace environment according to claim 1, wherein the gas flow rate of the mixed atmosphere in the steps one-6), one-8) and one-10) is 2-15L/min.
4. The method for measuring the coke reduction performance and the mechanical performance in a simulated blast furnace environment according to claim 1, wherein the holding time=6×temperature rise rate in the step one-7).
5. The method for measuring the coke reduction performance and the mechanical properties in a simulated blast furnace environment according to claim 1, wherein the holding time in the step one-9) is=2×heating rate+20.
6. The method for measuring the coke reduction performance and the mechanical performance of the simulated blast furnace environment according to claim 1, wherein the method comprises the steps of sampling before measurement and preprocessing the sample:
1) Crushing, screening and shaping the coke to obtain a coke sample with the granularity of 10-60 mm and a coke butyl sample with the granularity of 1-10 mm;
2) The pellets, the sintered ore or the natural lump ore are sieved to obtain iron ore samples with the granularity of 10-60 mm, and the iron ore samples are uniformly mixed and divided;
3) Limestone with granularity ranging from 1 mm to 10mm is obtained through crushing and sieving and is used as a slag former.
7. The method for measuring the coke reduction performance and the mechanical performance of the simulated blast furnace environment according to claim 1, wherein the sample components are determined before the measurement, the method comprises the following steps:
1) Ashing the coke to ensure the quality of the ash content of the coke to be more than 6 g;
2) The elemental components of the coke ash and the iron ore are measured, and the iron grade of the iron ore is measured by titration.
8. The method for measuring the coke reduction performance and the mechanical performance in the simulated blast furnace environment according to claim 1, wherein the method for weighing and placing the sample comprises the following steps:
1) Iron ore and coke are mixed according to the mass ratio of 8-1: 2-1, and recording the mass m of the iron ore 1 ；
2) Uniformly mixing the diced coke and the iron ore;
3) Calculating CaO content and SiO content of all the materials 2 Calculating the content and the alkalinity R of the comprehensive materials;
4) Adding limestone into the mixture of iron ore and diced coke to adjust the alkalinity R to be between 1.15 and 1.25;
5) Putting coke, a mixture of iron ore, diced coke and limestone into a crucible, wherein the coke is arranged below, and the mixture of iron ore, diced coke and limestone is arranged above, and the lower part of the graphite crucible is provided with a porous area, so that molten iron which is heated and melted can drop and be separated from the coke;
6) A layer of coke is further laid on top of the iron ore and the mixture of coke and limestone.
9. The method for measuring the coke reduction performance and the mechanical property simulating the blast furnace environment according to claim 8, wherein the coke breeze accounts for 2% -5% of the mass of the iron ore.
10. The method for measuring the coke reduction performance and the mechanical properties in a simulated blast furnace environment according to claim 1, wherein in the step one) -1), the crucible is heated while applying a pressure load of 0.01 to 1Mpa.
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