Ironmaking burdening calculation method based on residual CaO content of ton iron

Abstract

The application discloses a ton iron residual CaO content-based iron-making burden calculation method and relates to the field of iron-making processes. The method has the beneficial effect that, under the determined slag basicity range required for smelting, the correlation formula among the calcium oxide, silicon dioxide in the furnace-feeding raw materials and the calcium oxide, silicon dioxide and silicon content of the molten iron in the fuel is derived according to the calculation rules of the slag basicity, and the ton iron residual CaO content value meeting the current stage is calculated based on the existing smelting conditions, serving as an empirical reference constant for burden calculation. The empirical constant can be used to simply calculate how to adjust the raw material chemical composition or the raw material structure to meet the iron-making production.

Description

Technical Field

[0001] This invention relates to the field of ironmaking processes, and specifically to a method for calculating ironmaking feedstock based on the residual CaO content per ton of iron. Background Technology

[0002] Currently, blast furnaces commonly use a method that determines the binary basicity of the slag and then calculates the proportions of each component (sinter, pellets, and raw ore) based on material balance. Under normal circumstances, the raw materials for blast furnaces are mainly sinter, pellets, and raw ore, while the fuels are mainly coke and pulverized coal.

[0003] The iron content per ton of molten iron is 0.945, and the yield of molten iron is 0.99.

[0004] Silicon content in molten iron = Si%, molecular weight of silicon = 28, molecular weight of SiO2 = 60.

[0005] The sintering ratio of each batch of material is Z, and the proportion of CaO in the sintering is ZCaO, and the proportion of SiO2 is ZSiO2.

[0006] The pellet ratio of each batch of material is T, and the proportion of CaO in the pellets is TCaO, and the proportion of SiO2 is TSiO2.

[0007] The raw ore ratio of each batch is P, and the proportion of CaO in the raw ore is PCaO, and the proportion of SiO2 is PSiO2.

[0008] Total iron-containing ore quantity fed into the furnace for each batch = a, Overall furnace grade = Fe%; Z + T + P = 100%

[0009] The coke ratio of the blast furnace is K, the proportion of CaO in the coke is KCaO, and the proportion of SiO2 is KSiO2.

[0010] The coal ratio in the blast furnace is M, the proportion of CaO in the coal is MCaO, and the proportion of SiO2 is MSiO2.

[0011] The theoretical formula for calculating the binary alkalinity in slag is:

[0012]

[0013] Substituting, we get:

[0014]

[0015] As can be seen from the above formula, under the condition of a certain fuel ratio, it is very complicated to calculate the proportion of raw materials, which requires high technical skills from the operators at the blast furnace site and is not conducive to guiding practical production. Therefore, it is necessary to invent a simple method for calculating the proportion of raw materials. Summary of the Invention

[0016] The purpose of this invention is to address the shortcomings and defects of existing technologies by providing a method for calculating ironmaking feedstock based on the residual CaO content per ton of iron. This method, within a defined range of slag basicity required for smelting, derives a correlation formula between the calcium oxide and silicon dioxide content in the raw materials, the calcium oxide and silicon dioxide content in the fuel, and the silicon content in the molten iron, based on the calculation rules for slag basicity. Furthermore, based on existing smelting conditions, it calculates the residual CaO content per ton of iron for the current stage, serving as an empirical reference constant for feedstock calculation. Using this empirical constant, it is possible to easily calculate how to adjust the feedstock to meet the requirements of ironmaking production when the chemical composition or structure of the raw materials changes.

[0017] To achieve the above objectives, the present invention adopts the following technical solution: a method for calculating ironmaking feedstock based on the residual CaO content per ton of iron. By substituting the blast furnace slag basicity into the binary basicity theoretical calculation formula in the slag, we can obtain: Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Zsio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao +M×Mcao)], let Ф=Fe%÷0.945×0.99, because under blast furnace smelting conditions, all the CaO in the furnace charge enters the slag, most of the CaO in the slag combines with SiO2 to form stable glassy silicate slag, and a portion of the remaining CaO participates in desulfurization. Therefore, it can be known that: the difference between the total amount of CaO in the raw material entering the furnace and 1.2 times the total amount of SiO2 in the raw material entering the furnace, divided by the theoretical iron content, is called the residual calcium oxide per ton of iron (unit kg / t), that is: Substituting the formula Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Zsio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)] into the formula Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Z The equation sio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)] gives: Remaining CaO per ton of iron=[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)]×1000.

[0018] Furthermore, the theoretical formula for calculating the binary alkalinity in the slag is as follows: Substituting the following values: iron content per ton of molten iron = 0.945, molten iron yield = 0.99; silicon content in molten iron = Si%, molecular weight of silicon = 28, molecular weight of SiO2 = 60; sintering ratio of each batch of material is Z, CaO percentage in sinter = ZCaO, SiO2 percentage = ZSiO2; pelletizing ratio of each batch of material is T, CaO percentage in pellets = TCaO, SiO2 percentage = TSiO2; raw ore ratio of each batch of material is P, CaO percentage in raw ore = PCaO, SiO2 percentage = PSiO2; total ore amount of iron-containing material in each batch of blast furnace = a, overall grade in blast furnace = Fe%; Z + T + P = 100%; coke ratio of blast furnace is K, CaO percentage in coke = KCaO, SiO2 percentage = KSiO2; coal ratio of blast furnace is M, CaO percentage in coal = MCaO, SiO2 percentage = MSiO2; we obtain...

[0019] Furthermore, the basicity of the blast furnace slag is controlled between 1.18 and 1.22. Taking the midpoint R2 = 1.20, substituting it into the above theoretical formula for basicity, we get: Let Ф = Fe% ÷ 0.945 × 0.99, then the above formula can be simplified to... Then 1.2×[Z×Zsio2+T×Tsio2+P×Psio2+Ф×(K×Ksio2+M×Msio2)-Ф×Si%×2.143]=Z×Zcao+T×Tcao+P×Pcao+Ф×(K×Kcao+M×Mcao), which gives Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Zsio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)].

[0020] Furthermore, formula ② is derived from chemical analysis: KCaO = 0.3%, KSiO2 = 6.9%; MCaO = 0.9%, MSiO2 = 4.7%. Assuming the plant's average Si% during normal production is 0.3%, the coal ratio M is 0.15t / t, the coke ratio K is 0.35t / t, the overall grade of the feed material is Fe%, and the total amount of iron-containing material fed into the furnace per batch is a (unit ton). Therefore, the theoretical iron content of this material is a × Fe% / 0.945 × 0.99 (unit ton). Substituting formula ① into formula ② yields:

[0021] It is known that the residual calcium oxide per ton of iron involved in desulfurization is only related to the coal ratio, coke ratio, furnace temperature [Si]%, and fuel composition. When the production organization of an ironmaking plant is stable, the coal ratio, coke ratio, furnace temperature [Si]%, and fuel composition are basically controllable and change very little. Therefore, the residual calcium oxide value per ton of iron can be obtained as an empirical constant for desulfurization based on the plant's conventional smelting under certain furnace temperature and fuel ratio conditions.

[0022] After adopting the above technical solution, the beneficial effects of the present invention are as follows: The ironmaking batching calculation method has at least the following advantages:

[0023] 1. Under the given range of slag basicity required for smelting, the formula relating calcium oxide and silicon dioxide in the raw materials fed into the furnace to the calcium oxide and silicon dioxide in the fuel and the silicon content in the molten iron can be derived from the calculation rules of slag basicity.

[0024] 2. Based on the existing smelting conditions, calculate the remaining CaO content per ton of iron that meets the requirements of the current stage, and use it as an empirical reference constant for batching calculation.

[0025] 3. By using empirical constants, it is possible to easily calculate how to adjust the raw material chemical composition or structure to meet the requirements of ironmaking production when changes occur. Detailed Implementation

[0026] The technical solution adopted in this specific implementation is:

[0027] S1, the theoretical formula for calculating the binary alkalinity in the slag is:

[0028]

[0029] Substitution

[0030] The iron content per ton of molten iron is 0.945, and the yield of molten iron is 0.99.

[0031] Silicon content in molten iron = Si%, molecular weight of silicon = 28, molecular weight of SiO2 = 60.

[0032] The sintering ratio of each batch of material is Z, and the proportion of CaO in the sintering is ZCaO, and the proportion of SiO2 is ZSiO2.

[0033] The pellet ratio of each batch of material is T, and the proportion of CaO in the pellets is TCaO, and the proportion of SiO2 is TSiO2.

[0034] The raw ore ratio of each batch is P, and the proportion of CaO in the raw ore is PCaO, and the proportion of SiO2 is PSiO2.

[0035] Total iron-containing ore quantity fed into the furnace for each batch = a, Overall furnace grade = Fe%; Z + T + P = 100%

[0036] The coke ratio of the blast furnace is K, the proportion of CaO in the coke is KCaO, and the proportion of SiO2 is KSiO2.

[0037] The coal ratio in the blast furnace is M, the proportion of CaO in the coal is MCaO, and the proportion of SiO2 is MSiO2.

[0038] get

[0039]

[0040] S2, the basicity of the blast furnace slag is controlled between 1.18 and 1.22. Taking the midpoint R2 = 1.20, substituting it into the above theoretical formula for basicity, we get:

[0041]

[0042] Let Ф = Fe% ÷ 0.945 × 0.99, then the above formula can be simplified to...

[0043]

[0044] but

[0045] 1.2×[Z×Zsio2+T×Tsio2+P×Psio2+Ф×(K×Ksio2+M×Msio2)-Ф×Si%×2.143]=Z×Zcao+T×Tcao+P×Pcao+Ф×(K×Kcao+M×Mcao),

[0046] get

[0047] Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Zsio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)]

[0048] By substituting the basicity of blast furnace slag into the theoretical calculation formula for binary basicity in slag, we can obtain...

[0049] Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Zsio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)] ①

[0050] Under blast furnace smelting conditions, all the CaO in the furnace charge enters the slag. Most of the CaO in the slag combines with SiO2 to form stable glassy silicate slag, and a portion of the remaining CaO participates in desulfurization. Therefore, it can be concluded that:

[0051] The difference between the total amount of CaO fed into the furnace and 1.2 times the total amount of SiO2 fed into the furnace, divided by the theoretical iron content, is called the residual calcium oxide per ton of iron (unit: kg / t).

[0052]

[0053] Substituting formula ① into formula ②, we get:

[0054] Residual CaO per ton of iron = [1.2 × (K × Ksio2 + M × Msio2 - Si% × 2.143) - (K × Kcao + M × Mcao)] × 1000

[0055] The test results showed that: KCaO = 0.3%, KSiO2 = 6.9%; MCaO = 0.9%, MSiO2 = 4.7%;

[0056] Assuming the plant's average Si% is 0.3% during normal production, the coal ratio M is 0.15 t / t, the coke ratio K is 0.35 t / t, the overall grade of iron-containing material entering the furnace is Fe%, and the total amount of iron-containing material entering the furnace per batch is a (in tons), then the theoretical iron content of this material is a × Fe% / 0.945 × 0.99 (in tons). Substituting formula ① into formula ②, we get:

[0057]

[0058] It is known that the residual calcium oxide per ton of iron involved in desulfurization is only related to the coal ratio, coke ratio, furnace temperature [Si]%, and fuel composition. When the production organization of an ironmaking plant is stable, the coal ratio, coke ratio, furnace temperature [Si]%, and fuel composition are basically controllable and change very little. Therefore, the residual calcium oxide value per ton of iron can be obtained as an empirical constant for desulfurization based on the plant's conventional smelting under certain furnace temperature and fuel ratio conditions.

[0059] It should be noted that:

[0060] When calculating the empirical constant based on the formula: Residual CaO per ton of iron = [1.2 × (K × Ksio2 + M × Msio2 - Si% × 2.143) - (K × Kcao + M × Mcao)] × 1000, this value should be adjusted accordingly when there are significant changes in the chemical composition of coke, coal, and Si% content of molten iron.

[0061] 2. The quotient of the difference between the total amount of CaO in the raw materials and the total amount of SiO2 in the raw materials, divided by the theoretical amount of iron, should be controlled within the range of this empirical constant.

[0062] 3. Each ironworks must calculate the precise residual CaO value per ton of iron for its blast furnace under normal smelting conditions.

[0063] The following are relevant embodiments of the present invention:

[0064] At normal blast furnace smelting levels, the average Si% is 0.3%, the coal ratio M is controlled at 0.15 t / t, and the coke ratio K is controlled at 0.35 t / t; and KCaO = 0.3%, KSiO2 = 6.9%, MCaO = 0.9%, and MSiO2 = 4.7%, then the residual CaO per ton of iron is 27.3 (kg / t). Considering that the slag R2 fluctuation between 1.18 and 1.22 meets the production requirements, the actual residual CaO per ton of iron is allowed to fluctuate by ±1 (kg / t).

[0065] It is known that the production conditions before the change of feedstock conform to the range of the empirical constant for desulfurization, that is:

[0066] The sinter mix proportion Z = 70%, with CaO = 10.8% and SiO2 = 5.2% in the sinter; the sinter grade is 55.3%.

[0067] The pellet mix composition is T = 20%, with CaO = 1% and SiO2 = 6%; the pellet grade is 61%.

[0068] The raw ore mix proportion is P = 10%, with CaO = 0.3% and SiO2 = 3%; the raw ore grade is 61%.

[0069] Therefore, the overall grade of the furnace feed is 70% × 55.3% + 20% × 61% + 10% × 61% = 57%.

[0070] The remaining calcium oxide per ton of iron is calculated using formula ② to be 1 = 27.2 (kg / t).

[0071] Change A: Since the sintering machine has been overhauled and there is a surplus of sinter, it is necessary to increase the sintering ratio to 75%, decrease the pelletizing ratio to 15%, keep the raw ore ratio unchanged, and maintain the grade essentially unchanged. Therefore, guidance is needed on how to adjust the sinter composition to meet blast furnace production requirements.

[0072] The sinter mix proportion Z = 75%, with CaO = X and SiO2 = 10.8% + 5.2% - X; the sinter grade is 55.3%.

[0073] The pellet mix composition is T = 15%, with CaO = 1% and SiO2 = 6%; the pellet grade is 61%.

[0074] The raw ore mix proportion is P = 10%, with CaO = 0.3% and SiO2 = 3%; the raw ore grade is 61%.

[0075] Therefore, the overall grade of the furnace feed is 75% × 55.3% + 15% × 61% + 10% × 61% = 56.7%.

[0076] Substituting into formula ②, the remaining calcium oxide per ton of iron, A, is: A = {75% × X + 15% × 1% + 10% × 0.3% - 1.2 × [75% × (16% - X) + 15% × 6% + 10% × 3%]} × 1000 / (56.7% / 0.945 × 0.99) = 27.3.

[0077] The sinter content was calculated as CaO = X = 10.47% and SiO2 = 10.8% + 5.2% - X = 5.53%.

[0078] Change B: Analysis has shown that the actual composition of the sinter will change. Assuming the proportion of raw ore remains constant, guidance is needed on how to adjust the blast furnace burden structure to meet production requirements.

[0079] The sinter mix ratio is Z = X, with CaO = 11% and SiO2 = 6% in the sinter; the sinter grade is 55%.

[0080] The pellet mix proportion is T = 1 - 10% - X, with CaO = 1% and SiO2 = 6% in the pellets; the pellet grade is 61%.

[0081] The raw ore mix proportion is P = 10%, with CaO = 0.3% and SiO2 = 3%; the raw ore grade is 61%.

[0082] Therefore, the overall grade of the furnace feed = X × 55% + (1 - 10% - X) × 61% + 10% × 61%

[0083] Substituting into formula ②, the remaining calcium oxide B per ton of iron is: B = {X×11%+(1-10%-X)×1%+10%×0.3%-1.2×[X×6%+(1-10%-X)×6%+10%×3%]}×1000 / {[X×55%+(1-10%-X)×61%+10%×61%] / 0.945×0.99} = 27.3.

[0084] The sintering ratio X was found to be 75.2%, and the pellet ratio was 14.8%.

[0085] As can be seen from the above, the principle of this invention is based on the calculation of the empirical value of residual calcium oxide per ton of iron required for blast furnace slag desulfurization under the required furnace temperature, fuel ratio and fuel quality conditions during normal production. This empirical value is then used to guide the calculation of daily feed changes in sintering and blast furnace. Since the composition of coke and coal is relatively stable and changes very little, the amount of calculation caused by changes in coke and coal can be reduced, and the formula becomes simple and easy to calculate, which has strong practicality in actual production.

[0086] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for calculating ironmaking feedstock based on the residual CaO content per ton of iron, characterized in that: By substituting the basicity of blast furnace slag into the theoretical calculation formula for binary basicity in slag, we can obtain... Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Zsio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)] ① Let Ф = Fe% ÷ 0.945 × 0.99, Under blast furnace smelting conditions, all the CaO in the furnace charge enters the slag. Most of the CaO in the slag combines with SiO2 to form stable glassy silicate slag, and a portion of the remaining CaO participates in desulfurization. Therefore, it can be concluded that: The difference between the total amount of CaO fed into the furnace and 1.2 times the total amount of SiO2 fed into the furnace, divided by the theoretical iron content, is called the residual calcium oxide per ton of iron (unit: kg / t). ② Substituting formula ① into formula ②, we get: Remaining CaO per ton of iron = [1.2 × (K × Ksio2 + M × Msio2 - Si% × 2.143) - (K × Kcao + M × Mcao)] × 1000; The theoretical formula for calculating the binary alkalinity in the slag is as follows: Substitution The iron content per ton of molten iron is 0.945, and the yield of molten iron is 0.

99. The silicon content in molten iron is Si%, the molecular weight of silicon is 28, and the molecular weight of SiO2 is 60. The sintering ratio of each batch of material is Z, and the proportion of CaO in the sintering is ZCaO, and the proportion of SiO2 is ZSiO2. The pellet ratio of each batch of material is T, and the proportion of CaO in the pellets is TCaO, and the proportion of SiO2 is TSiO2. The raw ore ratio of each batch is P, and the proportion of CaO in the raw ore is PCaO, and the proportion of SiO2 is PSiO2. Total iron-containing ore quantity fed into the furnace for each batch = a, Overall furnace grade = Fe%; Z + T + P = 100% The coke ratio of the blast furnace is K, the proportion of CaO in the coke is KCaO, and the proportion of SiO2 is KSiO2. The coal ratio in the blast furnace is M, the proportion of CaO in the coal is MCaO, and the proportion of SiO2 is MSiO2. get ; The residual CaO content per ton of iron is used as an empirical constant for batching calculations. Using this empirical constant, it is easy to calculate how to adjust the raw material chemical composition or structure to meet the requirements of ironmaking production when changes occur.

2. The method for calculating ironmaking feedstock based on the residual CaO content per ton of iron according to claim 1, characterized in that: The basicity of the blast furnace slag is controlled between 1.18 and 1.

22. Taking the midpoint R2 = 1.20, and substituting it into the above theoretical calculation formula for basicity, we get: Let Ф = Fe% ÷ 0.945 × 0.99, The above formula can then be simplified to: but 1.2×[Z×Zsio2+T×Tsio2+P×Psio2+Ф×(K×Ksio2+M×Msio2)-Ф×Si%×2.143]=Z×Zcao+T×Tcao+P×Pcao+Ф×(K×Kcao+M×Mcao); get Z×Zcao+T×Tcao+P×Pcao-1.2×(Z×Zsio2+T×Tsio2+P×Psio2)=Ф×[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)].

3. The method for calculating ironmaking feedstock based on the residual CaO content per ton of iron according to claim 1, characterized in that: Formula ②, as determined by chemical analysis, shows that: KCaO = 0.3%, KSiO2 = 6.9%; MCaO = 0.9%, MSiO2 = 4.7%. Assuming the average Si% is 0.3% during normal factory production, the coal ratio M is 0.15t / t, the coke ratio K is 0.35t / t, the overall grade of iron-containing feed is Fe%, and the total amount of iron-containing feed per batch is a (in tons). Therefore, the theoretical iron content of the iron-containing raw material is a × Fe% / 0.945 × 0.99 (in tons). Substituting formula ① into formula ②, we get: =[1.2×(K×Ksio2+M×Msio2-Si%×2.143)-(K×Kcao+M×Mcao)]×1000 =[1.2×(0.35×6.9%+0.15×4.7%-0.3%×2.143)-（0.35×0.3%+0.15×0.9%)]×1000 =27.3 (unit: kg / t) It is known that the residual calcium oxide per ton of iron involved in desulfurization is only related to the coal ratio, coke ratio, furnace temperature [Si]%, and fuel composition. When the production organization of an ironmaking plant is stable, the coal ratio, coke ratio, furnace temperature [Si]%, and fuel composition are controllable and change very little. Therefore, the residual calcium oxide value per ton of iron can be obtained as an empirical constant for desulfurization under certain furnace temperature and fuel ratio conditions during the conventional smelting of the plant.

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