High-titanium blast furnace hearth oxygen potential characterization method

Abstract

The invention discloses a characterization method for oxygen potential of a high-titanium blast furnace hearth. The characterization method comprises the following steps: step (1), calculating oxygen partial pressure pCO of carbon monoxide gas in the target blast furnace hearth through a formula; (2) calculating the oxygen partial pressure of the oxygen gas in the target blast furnace hearth through a formula; and (3) the oxygen potential Ox in the target blast furnace hearth is calculated through a formula. According to the oxygen potential characterization method, a new method is established, the oxygen partial pressure in the blast furnace hearth can be calculated through simple calculation by utilizing part of process technical parameters and field production data of the blast furnace, and the oxygen potential of the blast furnace hearth is redefined and determined so as to assist a blast furnace operator in judging the current hearth state; and meanwhile, technological operation parameters can be adjusted and optimized in time, and the method is simple, efficient, practical and suitable for the high-titanium blast furnace.

Description

Technical Field

[0001] This invention relates to the field of blast furnace steelmaking technology, and specifically to a method for characterizing the oxygen potential of the hearth in a high-titanium blast furnace. Background Technology

[0002] Blast furnace ironmaking is a complex multiphase reaction process, and its core area—the hearth—is the final collection, refining, and storage site for molten iron and slag. The physicochemical environment within the hearth directly determines the quality of the molten iron, the lifespan of the furnace lining, and the overall operating efficiency of the blast furnace. Against this backdrop, oxygen potential, as a key thermodynamic indicator measuring the strength of the redox atmosphere within the hearth, is widely recognized for its importance in blast furnace smelting. Oxygen potential is usually defined as the relative chemical potential of oxygen in the system, often expressed as the relationship between the standard Gibbs free energy change and the oxygen partial pressure: ΔG°=RTlnpO2. In the high-temperature environment of the blast furnace hearth, oxygen potential directly affects a series of key metallurgical reactions. Particularly for vanadium-titanium magnetite smelting blast furnaces, increasing the hearth oxygen potential is a crucial measure to suppress the over-reduction of titanium dioxide in the slag, preventing and eliminating the formation of foamy slag, and achieving the desired vanadium-titanium ore smelting results. However, due to the extreme high temperature, high pressure, multiphase coexistence, and intense chemical reactions within the hearth, both theoretical calculations and direct on-site measurements of oxygen potential pose significant challenges. Currently, the academic and industrial communities have not yet formed a set of open and standardized formulas or empirical models for directly calculating the oxygen potential of the blast furnace hearth. Most research focuses on indirect measurement of the oxygen partial pressure of slag and iron through laboratory solid electrolytes. However, it is extremely difficult to conduct on-site, real-time measurement of the "black box" of the blast furnace hearth. At the same time, due to the extremely low oxygen partial pressure in the blast furnace hearth, the high temperature and the viscosity of high-titanium slag and iron, laboratory measurements are difficult, resulting in limited accuracy and reliability.

[0003] Therefore, developing a method for characterizing the oxygen potential of a high-titanium blast furnace hearth is of practical significance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for characterizing the oxygen potential of a high-titanium blast furnace hearth. A new method has been established that can calculate the oxygen partial pressure in the blast furnace hearth through simple calculation using some process parameters and on-site production data. The oxygen potential of the blast furnace hearth has been redefined and determined to assist blast furnace operators in judging the current hearth state. At the same time, it is beneficial to adjust and optimize process operating parameters in a timely manner. The method is simple, efficient, practical and applicable to high-titanium blast furnaces.

[0005] To achieve the above-mentioned objectives, this invention provides a method for characterizing the oxygen potential of a high-titanium blast furnace hearth, comprising the following steps: Step (1): Calculate the oxygen partial pressure p of carbon monoxide gas in the target blast furnace hearth using formula (1). CO ;

[0006] Where, p CO The oxygen partial pressure of carbon monoxide gas in the hearth of the target blast furnace, expressed in atm; P IN The blast furnace blast pressure is expressed in kPa; h t This is the horizontal distance from the air vent to the iron tap, in meters. and These represent the percentages of nitrogen and oxygen in the blower air, respectively (%). Oxygen enrichment rate, %; m, n, s, t, and h o constant Step (2): Calculate the oxygen partial pressure in the target blast furnace hearth using formula (2). ;

[0007] in, The oxygen partial pressure in the hearth of the target blast furnace is expressed in atm. R is the standard Gibbs free energy of the carbon-oxygen reaction in the hearth of the target blast furnace, in cal / mol; R is the gas constant 1.98718, in cal / (k·mol); T is the average temperature in the hearth of the target blast furnace, in K. Step (3): Calculate the oxygen potential O in the target blast furnace hearth using formula (3). x ;

[0008] Among them, O x The oxygen potential inside the hearth of the target blast furnace, in atm; The average oxygen partial pressure in the slag and iron of the target blast furnace hearth is expressed in atm.

[0009] According to the method for characterizing the oxygen potential of a high-titanium blast furnace hearth as described in this invention, preferably, in step (1), m, n, s, t, and h o The values ​​are 1.0 and 9.867 × 10, respectively. -3 0.192, 2.0 and 0.75.

[0010] According to the method for characterizing the oxygen potential of a high-titanium blast furnace hearth as described in this invention, preferably, in step (2), the standard Gibbs free energy of the carbon-oxygen reaction in the target blast furnace hearth is calculated using formula (3). ;

[0011] Where T is the average temperature inside the target blast furnace hearth, in K; a and b are -52.840 × 10⁻⁶ K. 3 And -42.14.

[0012] According to the method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to the present invention, preferably, in step (2), the average temperature T inside the target blast furnace hearth is obtained by calculation using formula (5);

[0013] Among them, T iron and T C These refer to the target blast furnace hearth temperature and the theoretical combustion temperature, respectively, in K.

[0014] According to the method for characterizing the oxygen potential of a high-titanium blast furnace hearth as described in the present invention, preferably, in step (3), the oxygen potential is obtained by calculation using formula (6).

[0015] in, The average oxygen partial pressure in the slag and iron inside the target blast furnace hearth, in atm; The oxygen partial pressure at equilibrium for different slag-iron reactions in the blast furnace hearth is expressed in atm, where i represents Si, Fe, and Ti, and n is an integer of 3.

[0016] According to the method for characterizing the oxygen potential of a high-titanium blast furnace hearth as described in the present invention, preferably, in step (3), the equilibrium oxygen partial pressure of the silicon-oxygen reaction in the target blast furnace hearth is obtained by calculation using formulas (7) and (8). ;

[0017]

[0018] in, The oxygen partial pressure at which the silicon-oxygen reaction equilibrium occurs in the hearth of the target blast furnace, expressed in atm. The standard Gibbs free energy of the silicon-oxygen reaction in the target blast furnace hearth is expressed in cal / mol. and These are the SiO2 activity coefficients in blast furnace slag and the Si activity coefficients in molten iron, respectively. and , where are the mass fractions of SiO2 and Si in the target blast furnace hearth slag and molten iron, respectively, %; c and d are constants -195.38 × 10⁻¹⁹. 3 And 52.24.

[0019] 7. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 5, characterized in that, in step (3), the oxygen partial pressure of the target blast furnace hearth iron-oxygen reaction equilibrium is obtained by calculation using formulas (9) and (10). ;

[0020] in, The oxygen partial pressure at equilibrium for the iron-oxygen reaction in the hearth of the target blast furnace, expressed in atm. The standard Gibbs free energy of the ferro-oxygen reaction in the hearth of the target blast furnace is expressed in cal / mol. and These are the FeO activity coefficients in the slag inside the hearth of the target blast furnace and the Fe activity coefficients in the molten iron, respectively. and The values ​​are: FeO and Fe, respectively, in the slag and molten iron within the target blast furnace hearth; e and f are -62.570 × 10⁻⁶. 3 And 13.59.

[0021] According to the method for characterizing the oxygen potential of a high-titanium blast furnace hearth as described in the present invention, preferably, in step (3), the oxygen partial pressure of the titanium-oxygen reaction equilibrium in the target blast furnace hearth is obtained by calculation using formulas (11) and (12). ;

[0022] in, The oxygen partial pressure at equilibrium for the silicon-oxygen reaction in the target blast furnace hearth, expressed in atm. The standard Gibbs free energy of the silicon-oxygen reaction in the blast furnace hearth is expressed in cal / mol. and These are the TiO2 activity coefficients of the slag in the hearth of the target blast furnace and the Ti activity coefficients of the molten iron, respectively. and The values ​​are the mass fractions of TiO2 and Ti in the slag and molten iron in the target blast furnace hearth, respectively (%). g and h are -203.800 × 10⁻⁶. 3 And 46.59.

[0023] According to the method for characterizing the oxygen potential in the hearth of a high-titanium blast furnace as described in the present invention, preferably, it further includes step (4), which involves converting the oxygen potential O in the target blast furnace hearth obtained in step (3) into a specific value. x The oxygen partial pressure is balanced by the reaction with titanium oxygen. By comparing the data, the condition of the target blast furnace hearth can be determined.

[0024] According to the method for characterizing oxygen potential in the hearth of a high-titanium blast furnace as described in the present invention, preferably, step (4) is determined by the following method; When O x ≥ At that time, it was determined that the oxygen potential in the hearth of the target blast furnace was sufficient; When O x < At that time, it was determined that the oxygen potential in the hearth of the target blast furnace was insufficient.

[0025] When the oxygen potential in the target blast furnace hearth is determined to be sufficient, it indicates that the formation of titanium carbonitride can be effectively suppressed, and the furnace is in good condition. When the oxygen potential in the target blast furnace hearth is determined to be insufficient, it indicates that titanium in the molten iron is prone to over-reduction, and the furnace is at risk of deterioration. Therefore, corresponding operations can be performed based on the above to avoid problems such as hearth adhesion.

[0026] It also includes step (5): saving the partial pressures of carbon monoxide and oxygen in the hearth of the target blast furnace, the partial pressure of oxygen in the slag-iron reaction equilibrium, and the oxygen potential in the hearth to the database.

[0027] The beneficial effects of this invention are: This invention provides a method for characterizing the oxygen potential in the hearth of a high-titanium blast furnace. This new method allows for the calculation of the oxygen partial pressure within the hearth using some blast furnace process parameters and on-site production data through simple calculations. It also redefines and determines the oxygen potential in the hearth, assisting blast furnace operators in judging the current hearth state. Furthermore, it facilitates timely adjustment and optimization of process operating parameters. The method is simple, efficient, practical, and applicable to high-titanium blast furnaces. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating the calculation process of a method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0031] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0032] Example Figure 1 This is a flowchart illustrating the calculation process of a method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to the present invention.

[0033] Collect process design parameters and production parameters of the target blast furnace hearth, including the plane distance from the blast furnace tuyeres to the taphole, blast pressure, oxygen enrichment rate, molten iron temperature, theoretical combustion temperature, molten iron composition, slag composition and other process technical parameters, and then output them to the database for storage. The specific data is shown in Table 1.

[0034] Table 1

[0035] In this embodiment, the oxygen potential of the hearth of a high-titanium blast furnace is characterized by the following steps: Step (1): Calculate the oxygen partial pressure p of carbon monoxide gas in the target blast furnace hearth using the following formula. CO :

[0036] Where, p CO The oxygen partial pressure of carbon monoxide gas in the hearth of the target blast furnace, expressed in atm; P IN The blast furnace blast pressure is expressed in kPa; h t This is the horizontal distance from the air vent to the iron tap, in meters. and These represent the percentages of nitrogen and oxygen in the blower air, respectively (%). Oxygen enrichment rate, %; m, n, s, t, and h o Let be constants, taken as 1.0 and 9.867 × 10⁻⁶ respectively. -3 The values ​​are 0.192, 2.0, and 0.75, and the specific values ​​can be selected according to the actual conditions of the blast furnace.

[0037] Substituting the data from Table 1, we can calculate p. CO =5.769483atm.

[0038] (2) The oxygen partial pressure of the target blast furnace hearth is obtained by calculating using the following formula. :

[0039]

[0040]

[0041] in, The oxygen partial pressure in the hearth of the target blast furnace is expressed in atm. R is the standard Gibbs free energy of the carbon-oxygen reaction in the target blast furnace hearth, in cal / mol; R is the gas constant, taken as 1.98718 cal / (k·mol); T is the average temperature of the target blast furnace hearth, in K; T iron and T CThese refer to the blast furnace molten iron temperature and the theoretical combustion temperature, respectively, in K; a and b are constants, taken as -52.840 × 10⁻⁶. 3 And -42.14.

[0042] Substitute the p calculated in step (1) CO We obtain T = 2146.15K. =8.51×10 -14 atm.

[0043] Step (3): Calculate the oxygen potential O in the target blast furnace hearth according to the following formula. x ; First, calculate the equilibrium oxygen partial pressure of the silicon-oxygen reaction in the target blast furnace hearth. :

[0044]

[0045] in, The oxygen partial pressure at equilibrium for the silicon-oxygen reaction in the target blast furnace hearth, expressed in atm. The standard Gibbs free energy of the silicon-oxygen reaction in the target blast furnace hearth is expressed in cal / mol. and The activity coefficients are 0.148 and 8.54, respectively, for the SiO2 activity coefficient in the slag and the Si activity coefficient in the molten iron of the target blast furnace hearth. and , where represents the mass fractions of SiO2 and Si in the slag and molten iron in the target blast furnace hearth, respectively; %; and c and d are constants, taken as -195.38 × 10⁻⁶. 3 And 52.24.

[0046] Secondly, the equilibrium oxygen partial pressure of the iron-oxygen reaction in the target blast furnace hearth is calculated using the following formula. :

[0047]

[0048] In the formula: The target blast furnace hearth ferro-oxygen reaction equilibrium oxygen partial pressure, atm; The standard Gibbs free energy of the ferro-oxygen reaction in the blast furnace hearth is expressed in cal / mol. and These are the FeO activity coefficients in blast furnace slag and Fe activity coefficients in molten iron, respectively, taken as 0.3 and 1.0; and , where are the mass fractions of FeO and Fe in blast furnace slag and molten iron, respectively; % and e and f are constants, taken as -62.570×103 and 13.59, respectively.

[0049] Next, the equilibrium oxygen partial pressure of the titanium-oxygen reaction in the target blast furnace hearth is calculated using the following formula. :

[0050]

[0051] in, The oxygen partial pressure at equilibrium for the silicon-oxygen reaction in the target blast furnace hearth, expressed in atm. The standard Gibbs free energy of the silicon-oxygen reaction in the target blast furnace hearth is expressed in cal / mol. and These are the TiO2 activity coefficients in the slag inside the hearth of the target blast furnace and the Ti activity coefficients in the molten iron, respectively, taken as 0.1 and 0.25; and The values ​​are the mass fractions of TiO2 and Ti in the slag and molten iron in the hearth of the target blast furnace, respectively, %; g and h are constants, taken as -203.800 × 10⁻⁶. 3 And 46.59.

[0052] Finally, the average oxygen partial pressure in the slag and iron inside the target blast furnace hearth is calculated using the following formula. :

[0053] in, The average oxygen partial pressure in the slag and iron inside the hearth of the target blast furnace, expressed in atm. The oxygen partial pressure for equilibrium reaction of different slag and iron in the target blast furnace hearth is expressed in atm. In this embodiment, i represents Si, Fe, Ti, etc.; n is an integer and is the number of slag and iron reactions in the hearth used in the calculation, which is taken as 3.

[0054] Substituting the above data and calculation results, we obtain =9.34×10 -9 atm, =1.42×10 -12 atm, =1.55×10 -9 atm, =3.63×10 -9 atm.

[0055] Based on the above calculation results, the target oxygen potential O in the blast furnace hearth is defined and obtained using the following formula. x :

[0056] Among them, O xThe oxygen potential in the hearth of the target blast furnace is expressed in atm.

[0057] Substituting the calculated data into the above data, we get O x =3.63×10 -9 atm.

[0058] Step (4): Determine the state of the target blast furnace hearth Based on the above calculation results, the oxygen potential O in the target blast furnace hearth is... x The oxygen partial pressure is balanced by the reaction with titanium oxygen. By comparison, we found that O x =3.63×10 -9 atm, =1.55×10 -9 atm, then O x > It can be concluded that the oxygen potential in the hearth of the current target blast furnace is relatively abundant, which can effectively suppress the formation of titanium carbonitride. The furnace is in good condition and no adjustment is needed at present.

[0059] Step (5): Save the partial pressures of carbon monoxide and oxygen in the hearth of the target blast furnace, the partial pressure of oxygen in the slag-iron reaction equilibrium, and the oxygen potential in the hearth to the database.

[0060] It should be noted that the components or steps in the above embodiments can be interleaved, substituted, added, or deleted. Therefore, the combinations formed by these reasonable permutations and transformations should also fall within the protection scope of the present invention, and the protection scope of the present invention should not be limited to the above embodiments.

[0061] The above are exemplary embodiments disclosed in this invention. The order of the disclosed embodiments is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this invention (including the claims) is limited to these examples. Various changes and modifications can be made without departing from the scope defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular.

[0062] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for characterizing the oxygen potential of a high-titanium blast furnace hearth, characterized in that, Includes the following steps: Step (1): Calculate the oxygen partial pressure p of carbon monoxide gas in the target blast furnace hearth using formula (1). CO ; Where, p CO The oxygen partial pressure of carbon monoxide gas in the hearth of the target blast furnace, expressed in atm; P IN The blast furnace blast pressure is expressed in kPa; h t This is the horizontal distance from the air vent to the iron tap, in meters. and These represent the percentages of nitrogen and oxygen in the blower air, respectively (%). Oxygen enrichment rate, %; m, n, s, t, and h o constant Step (2): Calculate the oxygen partial pressure in the target blast furnace hearth using formula (2). ; in, The oxygen partial pressure in the hearth of the target blast furnace is expressed in atm. R is the standard Gibbs free energy of the carbon-oxygen reaction in the hearth of the target blast furnace, in cal / mol; R is the gas constant 1.98718, in cal / (k·mol); T is the average temperature in the hearth of the target blast furnace, in K. Step (3): Calculate the oxygen potential O in the target blast furnace hearth using formula (3). x ; Among them, O x The oxygen potential inside the hearth of the target blast furnace, in atm; The average oxygen partial pressure in the slag and iron of the target blast furnace hearth is expressed in atm.

2. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 1, characterized in that, In step (1), m, n, s, t, and h o The values ​​are 1.0 and 9.867 × 10, respectively. -3 0.192, 2.0 and 0.

75.

3. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 1, characterized in that, In step (2), the standard Gibbs free energy of the carbon-oxygen reaction in the target blast furnace hearth is calculated using formula (3). ; Where T is the average temperature inside the target blast furnace hearth, in K; a and b are -52.840 × 10⁻⁶ K. 3 And -42.

14.

4. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 1, characterized in that, In step (2), the average temperature T inside the target blast furnace hearth is obtained by calculation using formula (5); Among them, T iron and T C These refer to the target blast furnace hearth temperature and the theoretical combustion temperature, respectively, in K.

5. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 1, characterized in that, In step (3), the result is obtained by calculating using formula (6). in, The average oxygen partial pressure in the slag and iron inside the target blast furnace hearth, in atm; The oxygen partial pressure at equilibrium for different slag-iron reactions in the blast furnace hearth is expressed in atm, where i represents Si, Fe, and Ti, and n is an integer of 3.

6. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 5, characterized in that, In step (3), the equilibrium oxygen partial pressure of the silicon-oxygen reaction in the target blast furnace hearth is calculated using formulas (7) and (8). ; in, The oxygen partial pressure at which the silicon-oxygen reaction equilibrium occurs in the hearth of the target blast furnace, expressed in atm. The standard Gibbs free energy of the silicon-oxygen reaction in the target blast furnace hearth is expressed in cal / mol. and These are the SiO2 activity coefficients in blast furnace slag and the Si activity coefficients in molten iron, respectively. and , where are the mass fractions of SiO2 and Si in the target blast furnace hearth slag and molten iron, respectively, %; c and d are constants -195.38 × 10⁻¹⁹. 3 And 52.

24.

7. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 5, characterized in that, In step (3), the oxygen partial pressure of the target blast furnace hearth iron-oxygen reaction equilibrium is obtained by calculating using formulas (9) and (10). ; in, The oxygen partial pressure at equilibrium for the iron-oxygen reaction in the hearth of the target blast furnace, expressed in atm. The standard Gibbs free energy of the ferro-oxygen reaction in the hearth of the target blast furnace is expressed in cal / mol. and These are the FeO activity coefficients in the slag inside the hearth of the target blast furnace and the Fe activity coefficients in the molten iron, respectively. and The values ​​are: FeO and Fe, respectively, in the slag and molten iron within the target blast furnace hearth; e and f are -62.570 × 10⁻⁶. 3 And 13.

59.

8. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 5, characterized in that, In step (3), the oxygen partial pressure of the titanium-oxygen reaction equilibrium in the target blast furnace hearth is obtained by calculating using formulas (11) and (12). ; in, The oxygen partial pressure at equilibrium for the silicon-oxygen reaction in the target blast furnace hearth, expressed in atm. The standard Gibbs free energy of the silicon-oxygen reaction in the blast furnace hearth is expressed in cal / mol. and These are the TiO2 activity coefficients of the slag in the hearth of the target blast furnace and the Ti activity coefficients of the molten iron, respectively. and The values ​​are the mass fractions of TiO2 and Ti in the slag and molten iron in the target blast furnace hearth, respectively (%). g and h are -203.800 × 10⁻⁶. 3 And 46.

59.

9. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 1, characterized in that, It also includes step (4), which calculates the target oxygen potential O in the blast furnace hearth obtained in step (3). x The oxygen partial pressure is balanced by the reaction with titanium oxygen. By comparing the data, the condition of the target blast furnace hearth can be determined.

10. The method for characterizing the oxygen potential of a high-titanium blast furnace hearth according to claim 9, characterized in that, Step (4): Determine using the following method; When O x ≥ At that time, it was determined that the oxygen potential in the hearth of the target blast furnace was sufficient; When O x < At that time, it was determined that the oxygen potential in the hearth of the target blast furnace was insufficient.

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