WO2014115526A1 - Preliminary processing method for molten iron - Google Patents
Preliminary processing method for molten iron Download PDFInfo
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- WO2014115526A1 WO2014115526A1 PCT/JP2014/000236 JP2014000236W WO2014115526A1 WO 2014115526 A1 WO2014115526 A1 WO 2014115526A1 JP 2014000236 W JP2014000236 W JP 2014000236W WO 2014115526 A1 WO2014115526 A1 WO 2014115526A1
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- WIPO (PCT)
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- slag
- furnace
- hot metal
- desiliconization
- height
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/04—Removing impurities other than carbon, phosphorus or sulfur
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
Definitions
- the present invention relates to a hot metal pretreatment method in which a hot metal desiliconization process and a dephosphorization process are continuously performed using a single converter-type refining furnace, with an intermediate exhausting process interposed therebetween.
- This two-time slagging method is a conventional pretreatment method in a converter-type smelting furnace, that is, a CaO-based solvent is introduced at the start of smelting to perform desiliconization / dephosphorization treatment on the hot metal in the converter-type smelting furnace.
- a CaO-based solvent is introduced at the start of smelting to perform desiliconization / dephosphorization treatment on the hot metal in the converter-type smelting furnace.
- the pretreatment method there are the following advantages. That is, (1) Since the desiliconization slag is discharged in the middle, it is possible to treat hot metal with a high silicon content, and it is possible to effectively utilize the silicon in the hot metal as a heat source. (2) Desiliconization slag in the middle Is advantageous in that the amount of CaO-based solvent used in the subsequent dephosphorization process can be reduced.
- the important point of operation is how to quickly discharge a predetermined amount of desiliconized slag from the furnace in a short time in the exhausting process after the desiliconization process. It becomes. In the case where the amount of desiliconized slag discharged in the evacuation process is small, the above effect cannot be obtained, which is equivalent to the pretreatment method in the conventional converter-type refining furnace described above.
- steelmaking slag including desiliconized slag and dephosphorized slag contains a large amount of iron oxide, and therefore tends to have a higher density than natural stone sand and blast furnace slag. For this reason, steelmaking slag has not been applied to civil engineering applications where it is feared that steelmaking slag may promote gravitational instability. Furthermore, since the volume per unit mass of steelmaking slag is smaller than that of natural stone sand, etc., an increase in transportation costs is also a drawback as a material for civil engineering work. In order to obtain a material that can be easily used for applications, it is desirable to reduce the bulk specific gravity of the steelmaking slag.
- the present inventors examined the discharge performance of the desiliconized slag in the discharge process after the desiliconization treatment. As a result, it was found that if the formation of desiliconization slag during desiliconization is small, the flowability of desiliconization slag is low and it is difficult to discharge a sufficient amount of desiliconization slag within a predetermined time. . Accordingly, it has been found that in order to allow a sufficient amount of desiliconized slag to flow out of the furnace quickly in the slagging process, the desiliconized slag must be stably formed during desiliconization blowing.
- slag forming is a phenomenon in which molten slag contains bubbles and apparently expands in volume.
- Patent Document 3 discloses that a sublance is measured while applying a constant frequency / amplitude vibration (forced vibration) to the sublance and simultaneously measuring the vibration of the sublance.
- Forced vibration has been proposed to detect the forming height of the in-furnace slag based on the amount of damping of the forced vibration.
- this method is based on the premise that the tip of the sublance is buried in the formed slag, and when the forming is small and the tip of the sublance is not buried in the formed slag, it is impossible to detect the forming height. Can not. Further, since the attenuation amount of the forced vibration varies depending on the composition and temperature of the slag to be generated, it is difficult to accurately detect the forming height.
- Patent Document 4 and Patent Document 5 propose a method of measuring the slag height during refining using a microwave.
- these technologies are forming detection technology in decarburization and refining of hot metal in the converter, and desiliconization slag in desiliconization in the hot metal pretreatment and converter slag in decarburization and refining in the converter. Since the slag temperature, basicity, and iron oxide concentration differ greatly, the electrical conductivity differs greatly. Therefore, the microwave reflection characteristics differ between desiliconization treatment and decarburization refining. The results cannot be applied to the desiliconization process as it is.
- the slag level is detected based on the frequency change of the mixed wave of the transmission wave and the reflected wave, or the slag level is detected from the reflectance of the microwave. It is described.
- the reflectivity of the microwave is very small and most of it is transmitted, so the reflected wave from the hot metal bath surface and the multiple reflected waves at the hot metal bath surface and slag surface are also Since it exists, the method of patent document 4 cannot detect a slag level.
- Patent Document 5 a transmission / reception antenna is inserted in the furnace, and in a refining furnace exposed to high-temperature slag or hot metal droplets, these droplets adhere to the antenna even in a short time of use. It is difficult to measure continuously during the refining period.
- the present invention has been made in view of the above circumstances, and the object of the present invention is to perform hot metal desiliconization treatment and dephosphorization treatment using a single converter-type refining furnace with an intermediate waste removal step in between.
- the target amount of desiliconized slag can be quickly and quickly removed from the furnace in a short period of time.
- the dephosphorization process of the next step it is possible to provide a hot metal pretreatment method that enables sufficient dephosphorization process in terms of cost and quality.
- Another object of the present invention is to provide a hot metal pretreatment method capable of obtaining a slag having a relatively small bulk specific gravity suitable for various civil engineering materials.
- a desiliconization process for supplying a gaseous oxygen source from an upper blow lance to hot metal in a converter-type refining furnace to desiliconize the hot metal, and at least a part of the slag generated in the desiliconization process Exhaust process discharged from the converter-type refining furnace, and after the exhaust process, a CaO-based solvent was added to the converter-type refining furnace, and a gaseous oxygen source was supplied from the upper blowing lance to remain.
- a hot metal pretreatment method characterized in that the desiliconization process is terminated in a state where the ratio of the freeboard in the furnace from the bath surface to the furnace opening is in a predetermined range.
- the supply flow rate of the gaseous oxygen source from the top blowing lance, the lance height of the top blowing lance, and the gas for stirring from the bottom blowing tuyere Adjusting at least one selected from the group of supply flow rate, composition of slag in the furnace, and amount of forming sedative material, and controlling the slag height in the furnace during desiliconization by this adjustment.
- the signal of the reflected wave closest to is determined as the signal of the reflected wave from the slag surface, the distance to the slag surface is obtained, and the slag height is measured based on the obtained distance to the slag surface.
- the hot metal pretreatment method according to any one of [1] to [4] above. [6] Of the reflected wave signals received by the distance meter, the distance to the object corresponding to the reflected wave signal does not change from the start of the desiliconization process, and the reflected waves that exist continuously.
- the hot metal preliminary processing method according to [5] wherein a signal of a reflected wave from the slag surface is determined after removing the signal as noise.
- a microwave having a frequency of 10 GHz or less is transmitted into the converter-type refining furnace, a reflected wave from the furnace is received, and the reflected wave reciprocates.
- the distance from the time to the target object is obtained, and the distance to the target object corresponding to the reflected wave signal from the target wave existing in the range from the furnace port to the hot metal bath surface is desiliconized.
- the reflected wave signal that is continuously present without any change from the beginning is removed as noise, and the reflected wave signal with the highest reflection intensity is removed except for the reflected wave signal corresponding to the hot metal bath surface.
- the distance to the slag surface is determined as a signal of a reflected wave from the surface, and the slag height is measured based on the determined distance to the slag surface.
- the hot metal preparation according to any one of Processing method. [8] After the completion of the dephosphorization process of the pre-charged hot metal in the converter type refining furnace, the hot metal subjected to the dephosphorization process is discharged, and the converter type is discharged without discharging the slag in the furnace generated by the dephosphorization process.
- Fresh hot metal left in the smelting furnace is charged into the converter-type smelting furnace, the hot metal is subjected to the desiliconization process, and the basicity of the slag in the furnace is set at the end of the desiliconization process. 0.8 to 1.5 or less, the temperature of the hot metal is 1280 ° C. or more and 1380 ° C. or less, the silicon content of the hot metal is 0.10% by mass or less, and in the exhausting process, 30 More than mass% is discharged out of the furnace, and then the dephosphorization process is performed on the hot metal in the furnace.
- the dephosphorized hot metal is discharged and the furnace generated by the dephosphorization process New hot metal is left in the converter-type smelting furnace without being discharged in the converter-type smelting furnace. Charged with, and performs preliminary processing on the molten iron, the above-mentioned [1] to molten iron pretreatment method according to any one of the above [7] to.
- the slag height in the furnace is measured during the dephosphorization process after the exhausting process, the supply flow rate of the gaseous oxygen source from the top blowing lance, the lance height of the top blowing lance, and the stirring from the bottom blowing tuyere
- the above [1] to [8] wherein at least one selected from the group of supply flow rates of the working gas is adjusted, and the slag in the furnace is controlled not to be ejected from the furnace port by this adjustment.
- the hot metal pretreatment method according to any one of the above.
- the hot metal desiliconization treatment and the dephosphorization treatment are continuously performed with an intermediate waste removal step interposed therebetween, the desiliconization treatment.
- the formed desiliconization slag is finished in a state where the height of the formed desiliconization slag is within a predetermined range with respect to the height of the freeboard in the furnace. It is possible to quickly discharge a predetermined amount of desiliconized slag as a target to the outside of the furnace in a short time after suppressing the sudden outflow of slag.
- the phosphorus concentration of the hot metal can be reduced to a low concentration with a small amount of CaO-based solvent used. It becomes possible.
- FIG. 1 is a schematic cross-sectional view of a converter-type refining furnace used when carrying out the hot metal pretreatment method according to the present invention.
- FIG. 2 is a schematic view showing the hot metal pretreatment method according to the present invention in the order of steps.
- FIG. 3 is a diagram illustrating an example of a reflected wave signal collected using a microwave slag level meter.
- FIG. 4 is a diagram showing the transition of the slag height in the furnace during the desiliconization process from the measurement result obtained by the microwave slag level meter.
- FIG. 5 is a diagram showing the relationship between the slag height at the end of the desiliconization process and the intermediate evacuation time.
- FIG. 6 is a diagram showing the relationship between the slag height at the end of the desiliconization process and the phosphorus concentration in the hot metal after the dephosphorization process.
- FIG. 7 is a diagram showing the influence of the acid feed rate from the top blowing lance on the slag height.
- FIG. 8 is a diagram showing the influence of the lance height of the top blowing lance on the slag height.
- FIG. 9 is a diagram showing the influence of the bottom blowing gas flow rate on the slag height.
- FIG. 10 is a graph showing the transition of the ratio of the slag height to the height of the free board in the furnace during the desiliconization process in Invention Examples 1 and 2 and Comparative Examples 1 and 2.
- FIG. 11 is a graph showing the transition of the ratio of the slag height to the height of the free board in the furnace during the dephosphorization process in Invention Example 3 and Comparative Example 2.
- FIG. 1 is a schematic cross-sectional view of a converter type refining furnace used when carrying out the hot metal pretreatment method according to the present invention
- FIG. 2 is a schematic view showing the hot metal pretreatment method according to the present invention in the order of steps.
- FIG. 1 is a diagram showing the desiliconization process of FIG. 2- (B).
- a converter-type refining furnace 1 capable of top bottom blowing as shown in FIG. 1 is used.
- the top blowing is performed by supplying an oxygen-containing gas toward the hot metal 5 as a gaseous oxygen source from the tip of the top blowing lance 2 via the top blowing lance 2 that can move up and down inside the converter type refining furnace 1.
- oxygen-containing gas oxygen gas, oxygen-enriched air, air, or a mixed gas of oxygen gas and inert gas can be used.
- FIG. 1 shows an example in which oxygen gas 8 is used as the oxygen-containing gas.
- the oxygen gas 8 is industrial pure oxygen.
- the bottom blowing is performed through a bottom blowing tuyere 3 provided at the bottom of the converter type refining furnace 1.
- the bottom blowing gas 9 may be a gas containing oxygen gas or only an inert gas such as argon gas or nitrogen gas. Moreover, it has the function of strengthening the stirring of the hot metal 5 by blowing it into the hot metal and accelerating the melting of the cold iron source, and also has the function of blowing the iron making agent into the hot metal together with the conveying gas from the bottom blowing tuyere 3. It may be a thing. Details of FIG. 1 will be described later.
- two or more converter-type refining furnaces 1 are used for refining the hot metal 5, and at least one of these converter-type refining furnaces 1 is used for the hot metal pretreatment according to the present invention, and the rest At least one group is used for decarburization refining of the hot metal 5 subjected to the hot metal pretreatment according to the present invention. That is, the pretreatment is performed in the converter type refining furnace 1 for hot metal pretreatment, and then the hot metal 5 subjected to the pretreatment is transferred to the converter type refining furnace 1 for decarburization refining and decarburization treatment is performed. .
- a charging pot 10 is placed in a converter-type refining furnace 1 in which a cold iron source 7 such as iron scrap is previously charged. Then, the hot metal 5 which has not been subjected to desiliconization and dephosphorization is charged (a hot metal charging step).
- a gaseous oxygen source or a gaseous oxygen source and a solid oxygen source such as iron oxide are supplied as an oxygen source to the hot metal 5 in the converter-type refining furnace, and desiliconization treatment is performed as shown in FIG. (Desiliconization process). Silicon contained in the hot metal 5 reacts with oxygen in the oxygen source (Si + 2O ⁇ SiO 2 ), and the desiliconization process proceeds. The hot metal temperature rises due to the oxidation heat of silicon by this desiliconization reaction, and the dissolution of the cold iron source 7 in the hot metal is promoted.
- the desiliconization process and the dephosphorization process are performed by using one converter-type refining furnace 1, and when the desiliconization process is performed, the dephosphorization slag generated by the decharge process of the precharge is performed. However, it remains attached to the furnace wall of the converter type refining furnace 1. Therefore, when the basicity ((mass% CaO) / (mass% SiO 2 )) (hereinafter sometimes simply referred to as “basicity”) of the silica removal slag 6 is not controlled in the silicon removal treatment.
- the phosphorous oxide (P 2 O 5 ) contained in the remaining dephosphorization slag is decomposed, and so-called “rebound” may occur in which the phosphorus concentration in the hot metal 5 increases. If dephosphorization slag is intentionally left in the furnace in order to reduce the amount of CaO-based solvent used during desiliconization, there is a possibility that the phosphorus concentration pick-up due to dephosphorization will become larger. That is, in order to prevent such recovery, it is preferable to adjust the basicity of the desiliconized slag 6 generated by the desiliconization process.
- the hot metal temperature is about 1300 ° C.
- the FeO concentration in the desiliconization slag is about 10 to 20% by mass.
- the basicity ((mass% CaO) / (mass% SiO 2 )) of the desiliconized slag 6 can be calculated based on the following formula (1).
- Basicity [(Remaining CaO amount in furnace (kg / molten metal-t)) + (Amount of added CaO in desiliconization treatment (kg / molten metal-t))] / [(Remaining SiO 2 amount in furnace (kg / molten metal) -t)) + (Amount of SiO 2 produced by desiliconization (kg / molten-t))] ...
- furnace residual amount of CaO and furnace residual amount of SiO 2 is the amount of CaO and SiO 2 amount contained in the dephosphorization slag before the charge remaining in the furnace, generating SiO 2 amount of desiliconization treatment Can be calculated from the change in the Si concentration in the hot metal before and after the silicon removal treatment.
- the oxygen source for the desiliconization treatment only the oxygen gas 8 from the top blowing lance 2 may be used, or the oxygen gas 8 and a solid oxygen source such as iron oxide (not shown) may be used in combination.
- a solid oxygen source such as iron oxide (not shown)
- iron oxide having a function of promoting the hatching of the CaO-based solvent. is there.
- the converter-type smelting furnace 1 is used as a smelting vessel, the oxygen gas supply rate can be increased, and even if the desiliconization process is performed using only the oxygen gas 8, the CaO-based solvent can be sufficiently used. It is possible to generate the desiliconized slag 6 having the target basicity by promoting the hatching.
- the converter type refining furnace 1 is tilted to the side opposite to the side where the outlet 4 is installed, and is generated by the desiliconization process.
- the desiliconized slag 6 containing a large amount of SiO 2 is discharged through a furnace port of the converter-type refining furnace 1 to a slag pot (not shown) disposed on the lower track (exhaust process).
- the converter-type refining furnace 1 is tilted within a range in which the molten iron 5 does not flow out of the furnace port, and the desiliconized slag 6 is discharged by the overflow from the furnace port, and the slag surface from the lower end of the tilted furnace body
- the hot metal 5 remaining in the converter type refining furnace is supplied with a CaO-based solvent and an oxygen source, and the hot metal 5 is dephosphorized as shown in FIG. Dephosphorization process).
- the oxygen source used in this dephosphorization process is mainly composed of the oxygen gas 8 from the top blowing lance 2 as in the desiliconization process, but a part of iron oxide may be used.
- the present invention is intended to dissolve a large amount of cold iron source 7, and as described above, it is possible to avoid using iron oxide that absorbs heat at the time of heating and decomposition as an oxygen source as much as possible. preferable.
- the CaO-based medium solvent used in the dephosphorization treatment quick lime, calcium carbonate or the like can be used. However, it is not limited to these, What contains 40 mass% or more of CaO, and contains other components, such as a fluorine, an alumina, and an iron oxide as needed, is also used as a CaO type
- a method for adding the CaO-based medium solvent granular and lump-shaped ones can be charged from a hopper on the furnace, and powdery ones can be charged through an upper blowing lance 2 or the like.
- Phosphorus in the hot metal is oxidized to oxygen in the supplied oxygen source to become phosphorus oxide (P 2 O 5 ), which is produced by the incubation of the CaO-based solvent and functions as a dephosphorizing refining agent.
- P 2 O 5 phosphorus oxide
- the converter-type refining furnace 1 is tilted to the side where the outlet 4 is installed, and the hot metal 5 in the converter-type refining furnace is passed through the outlet 4. Hot water is poured into a hot metal holding container (not shown) (a hot water discharge step).
- the converter type refining furnace 1 may be charged with the cold iron source 7 and the hot metal 5 to start the next charge desiliconization process.
- the cold iron source 7 and the hot metal 5 may be charged to start the next charge desiliconization process.
- the CaO content in the dephosphorization slag of the previous charge can be used as a CaO source in the desiliconization treatment of the next charge, reducing the amount of CaO-based solvent used during the desiliconization treatment can do.
- the desiliconization slag 6 when performing desiliconization treatment and dephosphorization treatment on the hot metal 5 in this way, the desiliconization slag 6 of a predetermined amount or more is quickly discharged out of the furnace in the exhausting step.
- the height of the desiliconized slag 6 is measured during the treatment, and the slag height (distance from the hot metal bath surface when stationary in the furnace to the upper end of the desiliconized slag 6) is the target range. Then, the desiliconization slag 6 is formed during the desiliconization process.
- the present inventors discharge a sufficient amount of the desiliconization slag 6 within a predetermined time. Make sure it is difficult to do. Therefore, in order to allow a sufficient amount of desiliconized slag 6 to flow out of the furnace quickly in the exhausting process, the desiliconized slag 6 is formed so as to be in a predetermined slag height range at the end of the desiliconization process. It is necessary to let Here, slag forming is a phenomenon in which molten slag contains bubbles and apparently expands in volume.
- the converter type refining furnace 1 used in the present invention is required to have a function of measuring the slag height in the furnace.
- a hood 12 for recovering exhaust gas generated from the furnace is provided above the furnace port of the converter type refining furnace 1.
- a flue 11 for introducing exhaust gas into the dust collector is provided at the top of the.
- the hood 12 is provided with an opening 13 and an opening 14, the upper blowing lance 2 is inserted into the furnace through the opening 13, and the pseudo-random signal processing radar passes through the opening 14.
- Two waveguides 16 attached to a system microwave distance meter 15 (hereinafter simply referred to as “microwave slag level meter 15”) are installed.
- a transmitting antenna 17 and a receiving antenna 18 are provided at positions directly below the opening 14 at the ends of the two waveguides 16, respectively. That is, the microwave slag level meter 15 is configured to measure the height of the desiliconized slag 6 in the furnace.
- the measurement sensitivity is improved by using a signal obtained by modulating the microwave with a pseudo-random signal.
- a pseudo-random signal for example, a pseudo-random signal that repeats the same waveform at a frequency of about 6 MHz that is generated by combining an appropriate logic circuit from a high-frequency clock signal of about 800 MHz can be used. This is an example of a case where the clock signal to generate a pseudo-random signal by 2 7 times (128 times) logic circuit is input to round it.
- a microwave carrier to be used for example, a microwave having a frequency of about 10 GHz is used, and a microwave that is modulated by multiplying a pseudo-random signal and a transmission antenna 17 installed in the opening 14 of the hood 12 on the furnace is used. And radiates toward the inside of the converter type refining furnace 1.
- the wavelength in the air of the electromagnetic wave with a frequency of 10 GHz is about 3.0 cm, and when it is less than 10 GHz, the wavelength is longer than that, which is sufficiently longer than the dust and smoke particles in the converter type refining furnace. Therefore, it is hardly affected by dust and the wavelength is short, which is advantageous for downsizing of the antenna.
- the transmitting antenna 17 and the receiving antenna 18 are, for example, horn antennas, and the reflected waves from other than the slag surface are made as small as possible by reducing the directivity sharply.
- the lower the frequency of the microwave, the less susceptible to dust and the like. Accordingly, the microwave used in the present invention has an upper frequency limit of 10 GHz, preferably lower than 10 GHz, and more preferably 8 GHz or lower. .
- the frequency of the microwave is too low, there is a problem that the resolution of time and distance is lowered, and the size of the antenna is required, which is not preferable for preventing dust from adhering to the antenna.
- the electromagnetic wave radiated from the transmitting antenna 17 into the converter type refining furnace is reflected on the slag surface and converted into an electric signal through the receiving antenna 18.
- the timing at which the input signal is supplied to the receiver of the microwave slag level meter 15 reciprocates the distance from the timing at which the electromagnetic wave is radiated from the transmitting antenna 17 to the slag level in the converter refining furnace.
- the electromagnetic wave is delayed by the propagation time of the electromagnetic wave until it reaches the receiving antenna 18. This propagation time can be measured by comparing the phase difference of a pseudo-random signal modulated on a microwave carrier wave between the received wave and the transmitted wave.
- the propagation time can be directly obtained from the time correlation function of the pseudo random signal component modulated into the received wave and the transmitted wave, but the pseudo random signal generated by slightly changing the clock frequency is used.
- the pseudo random signal generated by slightly changing the clock frequency is used.
- the phase difference within the repetition frequency period of the pseudo random signal of about 6 MHz that is, the time delay is converted into the time difference within the period of 4 kHz, and the time axis is expanded by about 1500 times,
- the phase difference between the pseudo-random signal of the received wave and the transmitted wave can be detected.
- the received reflected wave includes reflected waves from various paths and objects, and the reflected wave from each object has a pseudo-random signal component corresponding to the reflection intensity and the phase delay corresponding to the propagation time. It is included.
- signal processing using a pseudo-random signal with the above clock signal frequency changed is performed, and the propagation time is increased by about 1500 times when compared with a signal of a transmission wave that has been similarly processed. It expands and the signal according to the propagation time and intensity
- the signal detected in this way is detected by converting the time delay from the transmission wave into the propagation time, multiplying this by the microwave propagation velocity (3 ⁇ 10 8 m / s), and dividing by 2.
- the distance to the object corresponding to the received signal can be calculated.
- FIG. 3 shows the above-described microwave slag level meter when dephosphorization slag generated by the decharge process of the pre-charge is left in the furnace and the desiliconization process is performed after the molten iron 5 of the charge is charged in the furnace.
- 15 is an example of a reflected wave signal sampled using No. 15.
- FIG. 3 shows the relationship between the distance from the antenna of the object that is the source of the reflected wave and the intensity of the reflected wave.
- the horizontal axis of FIG. 3 uses a value obtained by converting the delay time of the detected signal from the transmission wave into the distance from the transmission antenna 17 and the reception antenna 18 to the object.
- detection signals of reflected waves having peaks at a plurality of positions are shown.
- a peak whose intensity is less than a certain value reflected wave signal
- the furnace body refractory and the furnace wall adhesion ground
- the peak of the reflected wave due to multiple reflection from gold or the top blowing lance 2 was assumed.
- the peak positions having an intensity of a certain value or more the peak closest to the distance to the furnace mouth with the distance from the antenna larger than the distance to the furnace mouth is the peak of the reflected wave from the slag surface. Peaked.
- the peak having an intensity of 100 times or more of the background level is larger than the distance to the furnace port and is the most in the distance to the furnace port.
- a peak corresponding to the surface of the formed desiliconized slag 6 was taken as the peak at the near peak position.
- the distance from the antenna to the position corresponding to the furnace opening is about 9 m, and a large wide peak whose distance from the antenna is about 19 m corresponds to the hot metal bath surface.
- the peak that has existed without changing the generation position (distance from the antenna) from the start of the desiliconization process does not correspond to the reflected wave from the slag surface, such a peak If the peak corresponding to the slag surface is determined as described above after removing the noise as a noise, a more reliable measurement is possible.
- the height relative to the reference surface (antenna position) of the slag surface determined by these methods, the height relative to the reference surface (antenna position) of the hot metal bath surface estimated from the sum of the amount of hot metal and iron scrap charged by the charge The absolute value of the difference was defined as the slag height.
- FIG. 4 the example which calculated
- FIG. 5 shows the results of the investigation of the relationship between the slag height at the end of the desiliconization treatment and the intermediate evacuation time, and the relationship between the slag height at the end of the desiliconization treatment and the phosphorus concentration in the hot metal after the completion of the dephosphorization treatment.
- the survey results are shown in FIG.
- the horizontal axis in FIGS. 5 and 6 indicates the height of the free board in the furnace with the slag height (also referred to as “empty part”, the space between the hot metal bath surface and the furnace port when stationary) The distance between the hot metal bath surface and the furnace opening).
- the ratio of the slag height to the height of the freeboard in the furnace exceeds 0.9, the forming of the desiliconized slag 6 will be too intense, and the furnace will be set up once during the evacuation to calm the desiliconized slag 6 It was necessary to take it, and the extension of the intermediate elimination time was invited.
- the ratio of the slag height to the height of the freeboard in the furnace is less than 0.5, the discharge performance of the desiliconized slag 6 at the time of intermediate discharge is poor, and in the dephosphorization process of the next step, the silicon removal Since the slag 6 remained excessively, the basicity of the slag decreased, and the phosphorus concentration in the hot metal after the dephosphorization treatment increased.
- the slag height of the desiliconized slag 6 is a predetermined range of 0.5 or more and 0.9 or less, preferably a predetermined range of 0.7 or more and 0.9 or less with respect to the height of the free board in the furnace.
- the upper limit value and the lower limit value of the predetermined range are considered to be different from each other depending on differences in the furnace profile and the shape of the furnace port, and therefore, FIG. 5 obtained in accordance with the embodiment in each refining furnace. It is more desirable to adjust the above upper limit value and lower limit value within the above range from the data shown in FIG.
- Fig. 7 shows the results of an investigation on the effect of the change in the slag height due to the change in the oxygen feed rate (oxygen gas supply flow rate) from the top blowing lance 2, and the slag height due to the change in the lance height of the top blowing lance 2
- FIG. 8 shows the result of the investigation on the influence on the change speed
- FIG. 9 shows the investigation result on the influence on the change speed of the slag height due to the change in the bottom blowing gas flow rate.
- the lance height of the upper blowing lance 2 is the distance from the lower end of the upper blowing lance 2 to the hot metal bath surface in a stationary state.
- the slag composition has a great influence on the slag height, and the slag height tends to increase as the low basicity, high iron oxide concentration, or high alumina concentration increases. It is also effective to add a slag-forming agent based on the height measurement result. Furthermore, when adjusting to reduce the slag height, it is also effective to use a forming soothing material such as a solid coolant or a gas generating substance.
- the height of the desiliconization slag 6 in the furnace is measured during the desiliconization process, and the supply flow rate of the gaseous oxygen source from the upper blowing lance 2 and the upper blowing lance are determined based on the measurement result. At least one selected from the group of the lance height of 2, the supply flow rate of the stirring gas from the bottom blowing tuyere 3, the composition of the slag in the furnace, and the amount of foaming sedative input, and this adjustment It is preferable to control so that the height of the desiliconized slag 6 is within a predetermined range. Thereby, it is possible to easily adjust the ratio of the slag height to the height of the free board in the furnace at the end of the desiliconization process within the predetermined range.
- the measurement of the slag height in the furnace is not limited to the desiliconization process, and can be performed in the dephosphorization process as described above.
- the dephosphorization slag is controlled so as not to be ejected (slipping) from the furnace port, thereby suppressing the ejection loss of the added CaO-based solvent and performing an efficient dephosphorization process. it can. That is, in the dephosphorization process, the ratio of the slag height to the height of the free board in the furnace may be adjusted to be less than 1.0. Even in the dephosphorization treatment, it is preferable to measure the slag height using the microwave slag level meter 15 described above.
- the basicity of the desiliconization slag 6 is set to 0.5 to 1.5 at the end of the desiliconization process, and the hot metal temperature or the desiliconization slag 6 is increased.
- the temperature is preferably set to 1280 ° C. or higher.
- the present inventors have released the desiliconized slag 6 discharged in the slag pot in the above slag pot from the slag pot to the yard and solidified it, and then pulverized it to a particle size of about 30 mm or less.
- Various characteristics of slag products were investigated.
- the unit volume mass of dephosphorized slag in the specified particle size and compacted state is about 2.0 to 2.3 kg / L, which is larger than 1.6 to 1.8 kg / L of natural debris material. Therefore, dephosphorization slag is suitable for applications where higher mass is preferred, for example, due to increased stability against waves, but for civil engineering applications where there is a concern that it may promote gravitational instability. Is difficult to apply, and also has the disadvantages of increased transportation costs due to its large bulk specific gravity.
- the basicity of the desiliconization slag 6 is 0.8 or more and 1.5 or less, and the hot metal temperature or the temperature of the desiliconization slag 6 is 1280 ° C or more and 1380 ° C or less. It is preferable to set the content to 0.10% by mass or less and to discharge 30% by mass or more of the desiliconized slag 6 in the exhausting step.
- the basicity of the desiliconized slag 6 By setting the basicity of the desiliconized slag 6 to 0.8 or more and 1.5 or less and the hot metal temperature or the temperature of the desiliconized slag 6 to 1280 ° C or more and 1380 ° C or less, it is possible to restore the precharge dephosphorization slag to the hot metal. It is possible to efficiently discharge the desiliconized slag 6 in the exhausting process while preventing phosphorus.
- the temperature of the desiliconization slag 6 is close to the hot metal temperature at the end of the desiliconization process, either the hot metal temperature or the temperature of the desiliconization slag 6 may be used as an index.
- the hot metal temperature can be measured by immersing a thermocouple in the hot metal, but instead of the measured value, the temperature and composition of the hot metal before the desiliconization treatment, the amount of various cold iron sources such as iron scrap, and various auxiliary substances such as quick lime
- the hot metal temperature calculated by calculating the heat balance from the operating conditions such as the amount of raw material used, the amount of various heating agents such as ferrosilicon, and the amount of oxygen gas supplied may be used.
- the silicon content in the hot metal after desiliconization to 0.10% by mass or less, even if the iron oxide concentration in the slag becomes relatively low, CO gas generation due to the decarburization reaction occurs during the desiliconization process. Since it becomes active, forming of the desiliconization slag 6 is promoted, which is advantageous in increasing the slag height at the end of the desiliconization process. Further, in this case, since the forming of the desiliconized slag 6 is maintained even during the discharging process and the slag height is maintained high, it is advantageous in terms of increasing the discharge efficiency of the desiliconized slag 6.
- the removal rate of the desiliconized slag 6 in the removal process is preferably 30% by mass or more.
- dephosphorizing agents such as quick lime in the dephosphorization treatment process without excessive accumulation of dephosphorization slag of the precharge in the furnace and without causing an excessive decrease in the slag basicity in the dephosphorization treatment process.
- the amount used can be suppressed and the phosphorus concentration in the hot metal can be lowered.
- the slag height in the furnace at the end of the desiliconization process was measured while satisfying the conditions at the end of the desiliconization process as described above, and the measured slag height was 0 with respect to the height of the freeboard in the furnace.
- the desiliconization slag 6 is discharged from the converter-type refining furnace 1 at a high removal rate in a relatively short time by adjusting the predetermined ratio such as .5 to 0.9 and performing the removal process. It becomes possible to do.
- the desiliconized slag 6 discharged to the slag pot in this way is further discharged from the slag pot to the yard and solidified, and then pulverized to a particle size of about 30 mm or less.
- the unit volume mass is reduced to about 1.2 kg / L or less. As a result, it is suitable for applications where a low specific gravity is desired, and an effect of reducing the transportation cost per construction volume can be obtained.
- the basicity of the desiliconized slag 6 at the end of the desiliconization treatment is 0.8 to 1.25 and the slag temperature is 1360 ° C. or less to increase the viscosity.
- Reducing the surface tension by setting the phosphoric acid (P 2 O 5 ) content in the slag at the end of desiliconization to 2% by mass or more, or using an inclined yard when discharging from the slag pot to the yard It is desirable to disperse the discharged slag over a wide range by increasing the cooling rate of the desiliconized slag 6 by discharging the slag pot while moving it.
- the average evacuation rate of the desiliconized slag 6 And the average unit volume mass increased to about 1.3 kg / L.
- the hot metal 5 is desiliconized and dephosphorized continuously with an intermediate waste process interposed therebetween.
- the desiliconization process is completed in a state where the height of the formed desiliconization slag 6 is in a predetermined range with respect to the height of the freeboard in the furnace during the desiliconization process.
- the subsequent evacuation process it is realized that a sufficient amount of desiliconized slag 6 is quickly discharged out of the furnace.
- the present invention is not limited to the above description, and various modifications can be made.
- the slag height is measured using the microwave slag level meter 15, but the measurement of the temperature profile in the height direction in the furnace, the measurement value of the top lance or the vibration meter attached to the furnace body.
- the slag height can also be measured from the detection information of the slag surface based on the measured value of the volume generated from the furnace body.
- the slag height is measured by using the converter type refining furnace having a capacity of 330 ton shown in FIG. 1 and measuring the slag height with the hot metal pretreatment (Invention Examples 1 to 3) according to the present invention and the microwave slag level meter.
- the hot metal preliminary treatment (Comparative Examples 1 and 2) according to the conventional method in which the above control was not performed was performed for 20 charges each.
- the target value of the phosphorus concentration in the hot metal at the end of the pretreatment was 0.030% by mass.
- Example 1 of the present invention during the desiliconization process, the slag height during oxygen blowing was measured using a microwave slag level meter, and among the acid feed rate from the top blowing lance, the lance height, and the stirring gas flow rate By adjusting at least one of the above, the ratio of the measured slag height to the freeboard height in the furnace supplies the amount of oxygen necessary for desiliconization obtained by assuming that the desiliconization oxygen efficiency is 50% At the end of the desiliconization treatment, the adjustment was made to be 0.5 to 0.9, intermediate waste was performed, and then the dephosphorization treatment was continued by oxygen blowing.
- Example 2 of the present invention during the desiliconization process, the slag height during oxygen blowing was measured using a microwave slag level meter, and among the acid feed rate from the top blowing lance, the lance height, and the stirring gas flow rate By adjusting at least one of the above, the ratio of the measured slag height to the freeboard height in the furnace supplies the amount of oxygen necessary for desiliconization obtained by assuming that the desiliconization oxygen efficiency is 50% At the end of the process, an attempt was made to adjust to 0.5 or more, but after the time had elapsed, the ratio of the slag height to the freeboard height in the furnace was less than 0.5. Extend the time, and when the slag height with respect to the height of the freeboard reaches 0.5, finish the desiliconization process and perform intermediate waste removal, and then continue the dephosphorization process by oxygen blowing. It was.
- the same control as in the present invention example 1 is performed in the desiliconization process, and then intermediate waste is performed, and then the slag height during oxygen blowing is reduced using a microwave slag level meter during the dephosphorization process.
- the ratio of the slag height to the height of the freeboard in the furnace is 0.8 or more, out of the acid feed rate from the top blowing lance, the lance height, and the stirring gas flow rate
- the dephosphorization treatment was performed by adjusting at least one of these so that the ratio of the slag height to the height of the free board in the furnace was less than 1.0.
- Comparative Example 1 and Comparative Example 2 the desiliconization process is terminated at the time when the amount of oxygen necessary for desiliconization obtained by assuming that the desiliconization oxygen efficiency is 50%, and intermediate waste is performed. Then, the dephosphorization process was continued by oxygen blowing.
- the hot metal temperature was 1300 ° C. or higher as Comparative Example 1, and the hot metal temperature was lower than 1300 ° C. as Comparative Example 2.
- the reason for dividing the comparative example into Comparative Example 1 and Comparative Example 2 is that when the hot metal temperature is as high as 1300 ° C. or higher, the slag hatching is promoted, and the slag height changes at a high level. When the hot metal temperature is less than 1300 ° C., the slag height is low.
- the acid feed rate during desiliconization was 30000 Nm 3 / hr
- the lance height was 2.5 m
- the bottom blowing gas flow rate was 1200 Nm 3 / hr.
- the acid feed rate during the dephosphorization treatment was 25000 Nm 3 / hr
- the lance height was 2.1 m
- the bottom blowing gas flow rate was 1200 Nm 3 / hr.
- nitrogen gas was used for both the desiliconization process and the dephosphorization process.
- Table 1 shows test results of representative examples of Invention Examples 1 to 3 and Comparative Examples 1 and 2.
- FIG. 10 shows the transition of the ratio of the slag height to the height of the free board in the furnace during the desiliconization process in each of the representative examples of the present invention examples 1 and 2 and comparative examples 1 and 2.
- FIG. 11 shows the change in the ratio of the slag height to the height of the free board in the furnace during the dephosphorization process in each of the representative examples of Invention Example 3 and Comparative Example 2.
- FIG. 10 and FIG. 11 representative examples are shown in Invention Examples 1 to 3 and Comparative Examples 1 and 2, respectively.
- Comparative Example 1 shown in Table 1 using hot metal having a temperature equivalent to that of Example 1 of the present invention the slag height is not controlled.
- the ratio of the slag height to the board height is 1.0, and the slag flow is severe at the time of intermediate evacuation.
- the furnace once tilted is raised again, the slag height is lowered using a sedative, and then the middle is again I was rejected. This increased the intermediate elimination time.
- the desiliconization process by oxygen blowing was continued, and when the ratio of the slag height to the freeboard height in the furnace reached 0.5, the desiliconization process was terminated, and then intermediate waste was performed. It was. Thereby, the rejection rate in the rejection process became as high as 70%.
- Comparative Example 2 shown in Table 1 using hot metal having the same temperature as Example 2 of the present invention since the slag height is not controlled, the desiliconization oxygen efficiency is assumed to be 50%. At the time when the oxygen amount necessary for the obtained silicon removal was finished, the slag height with respect to the height of the free board in the furnace was less than 0.5. As a result of performing the intermediate waste in that state, the waste rate was lowered, and the basicity of the subsequent dephosphorization treatment was lowered to cause dephosphorization failure.
- Example 3 of the present invention shown in Table 1 the slag height is controlled during the desiliconization process, and the ratio of the slag height to the freeboard height in the furnace is less than 1.0 during the dephosphorization process.
- the acid feed rate is in the range of ⁇ 5000 Nm 3 / hr
- the lance height is in the range of ⁇ 0.5 m
- the bottom blowing gas flow rate is in the range of ⁇ 1200 Nm 3 / hr, either one or two More species adjustments were made.
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Abstract
Description
[1]転炉型精錬炉内の溶銑に上吹きランスから気体酸素源を供給して溶銑を脱珪処理する脱珪処理工程と、該脱珪処理工程で生成したスラグの少なくとも一部を前記転炉型精錬炉から排出する排滓工程と、該排滓工程後、前記転炉型精錬炉内にCaO系媒溶剤を添加し、前記上吹きランスから気体酸素源を供給して残留させた溶銑を脱燐処理する脱燐処理工程と、を有する溶銑の予備処理方法であって、前記脱珪処理中に炉内のスラグ高さを測定し、測定されたスラグ高さが炉内の溶銑浴面から炉口までの炉内フリーボードの高さに対して所定の範囲の比率となっている状態で、脱珪処理を終了することを特徴とする、溶銑の予備処理方法。
[2]前記比率の所定の範囲が0.5~0.9の範囲であることを特徴とする、上記[1]に記載の溶銑の予備処理方法。
[3]前記スラグ高さの測定結果に基づいて、前記脱珪処理中に、上吹きランスからの気体酸素源の供給流量、上吹きランスのランス高さ、底吹き羽口からの攪拌用ガスの供給流量、炉内のスラグの組成、フォーミング鎮静材の投入量の群から選択された少なくとも1種を調整し、この調整によって脱珪処理中における炉内のスラグ高さを制御することを特徴とする、上記[1]または上記[2]に記載の溶銑の予備処理方法。
[4]前記脱珪処理中における前記スラグ高さの炉内フリーボードの高さに対する比率が0.5~0.9の範囲内となるように、脱珪処理中における炉内のスラグ高さを制御することを特徴とする、上記[3]に記載の溶銑の予備処理方法。
[5]擬似ランダム信号処理レーダー方式マイクロ波距離計を用い、10GHz以下の周波数のマイクロ波を前記転炉型精錬炉内に送信して反射波を受信し、反射波の往復伝播時間から対象物までの距離を求め、受信した或る所定の強度以上の反射波の信号のうちで、反射波の信号に対応する対象物までの距離が炉口までの距離よりも大きく且つ炉口までの距離に最も近い反射波の信号をスラグ表面からの反射波の信号と判定してスラグ表面までの距離を求め、求めたスラグ表面までの距離に基づいて前記スラグ高さを測定することを特徴とする、上記[1]ないし上記[4]の何れか1項に記載の溶銑の予備処理方法。
[6]前記距離計で受信される反射波の信号のうちで、反射波の信号に対応する対象物までの距離が脱珪処理開始時から変化せずに、継続して存在する反射波の信号をノイズとして除去したうえで、前記スラグ表面からの反射波の信号を判定することを特徴とする、上記[5]に記載の溶銑の予備処理方法。
[7]擬似ランダム信号処理レーダー方式マイクロ波距離計を用い、10GHz以下の周波数のマイクロ波を前記転炉型精錬炉内に送信して炉内からの反射波を受信し、反射波の往復伝播時間から対象物までの距離を求め、炉口から溶銑浴面までの範囲に存在する対象物からの反射波の信号のうちで、反射波の信号に対応する対象物までの距離が脱珪処理開始時から変化せずに、継続して存在する反射波の信号をノイズとして除去したうえで、溶銑浴面に対応する反射波の信号を除いて最も反射強度が高い反射波の信号をスラグ表面からの反射波の信号と判定してスラグ表面までの距離を求め、求めたスラグ表面までの距離に基づいて前記スラグ高さを測定することを特徴とする、上記[1]ないし上記[4]の何れか1項に記載の溶銑の予備処理方法。
[8]前記転炉型精錬炉における前チャージの溶銑の脱燐処理工程終了後、脱燐処理した溶銑を出湯し、脱燐処理で生成した炉内のスラグを排出せずに前記転炉型精錬炉内に残留させた状態で新たな溶銑を前記転炉型精錬炉内に装入し、該溶銑に前記脱珪処理工程を施し、該脱珪処理終了時に、炉内スラグの塩基度を0.8以上1.5以下、溶銑の温度を1280℃以上1380℃以下、溶銑の珪素含有量を0.10質量%以下とし、前記排滓工程では、脱珪処理工程で生成したスラグの30質量%以上を炉外に排出し、その後、炉内の溶銑に前記脱燐処理工程を施し、該脱燐処理工程終了後、脱燐処理した溶銑を出湯し、脱燐処理で生成した炉内のスラグを排出せずに前記転炉型精錬炉内に残留させた状態で新たな溶銑を前記転炉型精錬炉内に装入し、この溶銑に対して予備処理を行うことを特徴とする、上記[1]ないし上記[7]の何れか1項に記載の溶銑の予備処理方法。
[9]排滓工程後の脱燐処理中に炉内のスラグ高さを測定し、上吹きランスからの気体酸素源の供給流量、上吹きランスのランス高さ、底吹き羽口からの攪拌用ガスの供給流量の群から選択された少なくとも1種を調整し、この調整により炉内のスラグが炉口から噴出しないように制御することを特徴とする、上記[1]ないし上記[8]の何れか1項に記載の溶銑の予備処理方法。 The gist of the present invention for solving the above problems is as follows.
[1] A desiliconization process for supplying a gaseous oxygen source from an upper blow lance to hot metal in a converter-type refining furnace to desiliconize the hot metal, and at least a part of the slag generated in the desiliconization process Exhaust process discharged from the converter-type refining furnace, and after the exhaust process, a CaO-based solvent was added to the converter-type refining furnace, and a gaseous oxygen source was supplied from the upper blowing lance to remain. A dephosphorization process for dephosphorizing the hot metal, and measuring the slag height in the furnace during the desiliconization process, and the measured slag height is the hot metal in the furnace A hot metal pretreatment method, characterized in that the desiliconization process is terminated in a state where the ratio of the freeboard in the furnace from the bath surface to the furnace opening is in a predetermined range.
[2] The hot metal pretreatment method according to [1], wherein the predetermined range of the ratio is in a range of 0.5 to 0.9.
[3] Based on the measurement result of the slag height, during the desiliconization process, the supply flow rate of the gaseous oxygen source from the top blowing lance, the lance height of the top blowing lance, and the gas for stirring from the bottom blowing tuyere Adjusting at least one selected from the group of supply flow rate, composition of slag in the furnace, and amount of forming sedative material, and controlling the slag height in the furnace during desiliconization by this adjustment The hot metal pretreatment method according to [1] or [2] above.
[4] The slag height in the furnace during the desiliconization process so that the ratio of the slag height to the height of the freeboard in the furnace during the desiliconization process is in the range of 0.5 to 0.9. The hot metal pretreatment method according to [3], wherein the hot metal is controlled.
[5] Using a pseudo-random signal processing radar type microwave rangefinder, a microwave having a frequency of 10 GHz or less is transmitted into the converter-type refining furnace to receive a reflected wave. The distance to the object corresponding to the reflected wave signal is greater than the distance to the furnace port and the distance to the furnace port among the received reflected wave signals with a certain intensity or higher. The signal of the reflected wave closest to is determined as the signal of the reflected wave from the slag surface, the distance to the slag surface is obtained, and the slag height is measured based on the obtained distance to the slag surface. The hot metal pretreatment method according to any one of [1] to [4] above.
[6] Of the reflected wave signals received by the distance meter, the distance to the object corresponding to the reflected wave signal does not change from the start of the desiliconization process, and the reflected waves that exist continuously The hot metal preliminary processing method according to [5], wherein a signal of a reflected wave from the slag surface is determined after removing the signal as noise.
[7] Using a pseudo-random signal processing radar-type microwave rangefinder, a microwave having a frequency of 10 GHz or less is transmitted into the converter-type refining furnace, a reflected wave from the furnace is received, and the reflected wave reciprocates. The distance from the time to the target object is obtained, and the distance to the target object corresponding to the reflected wave signal from the target wave existing in the range from the furnace port to the hot metal bath surface is desiliconized. The reflected wave signal that is continuously present without any change from the beginning is removed as noise, and the reflected wave signal with the highest reflection intensity is removed except for the reflected wave signal corresponding to the hot metal bath surface. [1] to [4], wherein the distance to the slag surface is determined as a signal of a reflected wave from the surface, and the slag height is measured based on the determined distance to the slag surface. The hot metal preparation according to any one of Processing method.
[8] After the completion of the dephosphorization process of the pre-charged hot metal in the converter type refining furnace, the hot metal subjected to the dephosphorization process is discharged, and the converter type is discharged without discharging the slag in the furnace generated by the dephosphorization process. Fresh hot metal left in the smelting furnace is charged into the converter-type smelting furnace, the hot metal is subjected to the desiliconization process, and the basicity of the slag in the furnace is set at the end of the desiliconization process. 0.8 to 1.5 or less, the temperature of the hot metal is 1280 ° C. or more and 1380 ° C. or less, the silicon content of the hot metal is 0.10% by mass or less, and in the exhausting process, 30 More than mass% is discharged out of the furnace, and then the dephosphorization process is performed on the hot metal in the furnace. After the dephosphorization process is completed, the dephosphorized hot metal is discharged and the furnace generated by the dephosphorization process New hot metal is left in the converter-type smelting furnace without being discharged in the converter-type smelting furnace. Charged with, and performs preliminary processing on the molten iron, the above-mentioned [1] to molten iron pretreatment method according to any one of the above [7] to.
[9] The slag height in the furnace is measured during the dephosphorization process after the exhausting process, the supply flow rate of the gaseous oxygen source from the top blowing lance, the lance height of the top blowing lance, and the stirring from the bottom blowing tuyere The above [1] to [8], wherein at least one selected from the group of supply flow rates of the working gas is adjusted, and the slag in the furnace is controlled not to be ejected from the furnace port by this adjustment. The hot metal pretreatment method according to any one of the above.
塩基度=[(炉内残留CaO量(kg/溶銑-t))+(脱珪処理での添加CaO量(kg/溶銑-t))]/[(炉内残留SiO2量(kg/溶銑-t))+(脱珪処理での生成SiO2量(kg/溶銑-t))]・・・(1)
尚、炉内残留CaO量及び炉内残留SiO2量は、炉内に残留する前チャージの脱燐スラグ中に含有されるCaO量及びSiO2量であり、脱珪処理での生成SiO2量は、脱珪処理前後の溶銑中Si濃度の変化から算出できる。 The basicity ((mass% CaO) / (mass% SiO 2 )) of the
Basicity = [(Remaining CaO amount in furnace (kg / molten metal-t)) + (Amount of added CaO in desiliconization treatment (kg / molten metal-t))] / [(Remaining SiO 2 amount in furnace (kg / molten metal) -t)) + (Amount of SiO 2 produced by desiliconization (kg / molten-t))] ... (1)
Incidentally, furnace residual amount of CaO and furnace residual amount of SiO 2 is the amount of CaO and SiO 2 amount contained in the dephosphorization slag before the charge remaining in the furnace, generating SiO 2 amount of desiliconization treatment Can be calculated from the change in the Si concentration in the hot metal before and after the silicon removal treatment.
2 上吹きランス
3 底吹き羽口
4 出湯口
5 溶銑
6 脱珪スラグ
7 冷鉄源
8 酸素ガス
9 底吹きガス
10 装入鍋
11 煙道
12 フード
13 開口部
14 開口部
15 マイクロ波スラグレベル計
16 導波管
17 送信アンテナ
18 受信アンテナ DESCRIPTION OF
Claims (9)
- 転炉型精錬炉内の溶銑に上吹きランスから気体酸素源を供給して溶銑を脱珪処理する脱珪処理工程と、該脱珪処理工程で生成したスラグの少なくとも一部を前記転炉型精錬炉から排出する排滓工程と、該排滓工程後、前記転炉型精錬炉内にCaO系媒溶剤を添加し、前記上吹きランスから気体酸素源を供給して残留させた溶銑を脱燐処理する脱燐処理工程と、を有する溶銑の予備処理方法であって、前記脱珪処理中に炉内のスラグ高さを測定し、測定されたスラグ高さが炉内の溶銑浴面から炉口までの炉内フリーボードの高さに対して所定の範囲の比率となっている状態で、脱珪処理を終了することを特徴とする、溶銑の予備処理方法。 A desiliconization process for supplying a gaseous oxygen source to the hot metal in the converter type refining furnace from the top blowing lance to desiliconize the hot metal, and at least part of the slag generated in the desiliconization process is converted into the converter type An exhausting process for discharging from the refining furnace, and after the exhausting process, a CaO-based medium solvent is added into the converter type refining furnace, and a gaseous oxygen source is supplied from the upper blowing lance to remove the remaining hot metal. A hot metal pretreatment method comprising: measuring a slag height in the furnace during the desiliconization process, and measuring the slag height from the hot metal bath surface in the furnace. A hot metal preliminary treatment method, characterized in that the desiliconization process is terminated in a state where the ratio is within a predetermined range with respect to the height of the in-furnace freeboard to the furnace opening.
- 前記比率の所定の範囲が0.5~0.9の範囲であることを特徴とする、請求項1に記載の溶銑の予備処理方法。 The hot metal pretreatment method according to claim 1, wherein the predetermined range of the ratio is in the range of 0.5 to 0.9.
- 前記スラグ高さの測定結果に基づいて、前記脱珪処理中に、上吹きランスからの気体酸素源の供給流量、上吹きランスのランス高さ、底吹き羽口からの攪拌用ガスの供給流量、炉内のスラグの組成、フォーミング鎮静材の投入量の群から選択された少なくとも1種を調整し、この調整によって脱珪処理中における炉内のスラグ高さを制御することを特徴とする、請求項1または請求項2に記載の溶銑の予備処理方法。 Based on the measurement result of the slag height, during the desiliconization process, the supply flow rate of the gaseous oxygen source from the top blowing lance, the lance height of the top blowing lance, the supply flow rate of the stirring gas from the bottom blowing tuyere The composition of the slag in the furnace, adjusting at least one selected from the group of the amount of forming sedative material, the slag height in the furnace during the desiliconization process is controlled by this adjustment, The hot metal pretreatment method according to claim 1 or 2.
- 前記脱珪処理中における前記スラグ高さの炉内フリーボードの高さに対する比率が0.5~0.9の範囲内となるように、脱珪処理中における炉内のスラグ高さを制御することを特徴とする、請求項3に記載の溶銑の予備処理方法。 The slag height in the furnace during the desiliconization process is controlled so that the ratio of the slag height to the height of the freeboard in the furnace during the desiliconization process is in the range of 0.5 to 0.9. The hot metal pretreatment method according to claim 3, wherein:
- 擬似ランダム信号処理レーダー方式マイクロ波距離計を用い、10GHz以下の周波数のマイクロ波を前記転炉型精錬炉内に送信して反射波を受信し、反射波の往復伝播時間から対象物までの距離を求め、受信した或る所定の強度以上の反射波の信号のうちで、反射波の信号に対応する対象物までの距離が炉口までの距離よりも大きく且つ炉口までの距離に最も近い反射波の信号をスラグ表面からの反射波の信号と判定してスラグ表面までの距離を求め、求めたスラグ表面までの距離に基づいて前記スラグ高さを測定することを特徴とする、請求項1ないし請求項4の何れか1項に記載の溶銑の予備処理方法。 Using a pseudo-random signal processing radar-type microwave rangefinder, a microwave with a frequency of 10 GHz or less is transmitted into the converter type refining furnace to receive a reflected wave, and the distance from the round-trip propagation time of the reflected wave to the object Among the received reflected wave signals having a certain intensity or higher, the distance to the object corresponding to the reflected wave signal is larger than the distance to the furnace port and closest to the distance to the furnace port The reflected wave signal is determined as a reflected wave signal from the slag surface, a distance to the slag surface is obtained, and the slag height is measured based on the obtained distance to the slag surface. The hot metal pretreatment method according to any one of claims 1 to 4.
- 前記距離計で受信される反射波の信号のうちで、反射波の信号に対応する対象物までの距離が脱珪処理開始時から変化せずに、継続して存在する反射波の信号をノイズとして除去したうえで、前記スラグ表面からの反射波の信号を判定することを特徴とする、請求項5に記載の溶銑の予備処理方法。 Among the reflected wave signals received by the distance meter, the distance to the object corresponding to the reflected wave signal does not change from the start of the desiliconization process, and the reflected wave signal that exists continuously is noise. The hot metal preliminary processing method according to claim 5, wherein a signal of a reflected wave from the surface of the slag is determined after the removal.
- 擬似ランダム信号処理レーダー方式マイクロ波距離計を用い、10GHz以下の周波数のマイクロ波を前記転炉型精錬炉内に送信して炉内からの反射波を受信し、反射波の往復伝播時間から対象物までの距離を求め、炉口から溶銑浴面までの範囲に存在する対象物からの反射波の信号のうちで、反射波の信号に対応する対象物までの距離が脱珪処理開始時から変化せずに、継続して存在する反射波の信号をノイズとして除去したうえで、溶銑浴面に対応する反射波の信号を除いて最も反射強度が高い反射波の信号をスラグ表面からの反射波の信号と判定してスラグ表面までの距離を求め、求めたスラグ表面までの距離に基づいて前記スラグ高さを測定することを特徴とする、請求項1ないし請求項4の何れか1項に記載の溶銑の予備処理方法。 Using a pseudo-random signal processing radar type microwave rangefinder, a microwave with a frequency of 10 GHz or less is transmitted to the converter type refining furnace, a reflected wave from the furnace is received, and the target is determined from the round-trip propagation time of the reflected wave. Find the distance to the object, and among the reflected wave signals from the object existing in the range from the furnace port to the hot metal bath surface, the distance to the object corresponding to the reflected wave signal is The reflected wave signal that is continuously present without any change is removed as noise, and the reflected wave signal with the highest reflection intensity is reflected from the slag surface except for the reflected wave signal corresponding to the hot metal bath surface. The distance to the slag surface is determined by determining the signal as a wave, and the slag height is measured based on the obtained distance to the slag surface. Pretreatment method of hot metal as described in .
- 前記転炉型精錬炉における前チャージの溶銑の脱燐処理工程終了後、脱燐処理した溶銑を出湯し、脱燐処理で生成した炉内のスラグを排出せずに前記転炉型精錬炉内に残留させた状態で新たな溶銑を前記転炉型精錬炉内に装入し、該溶銑に前記脱珪処理工程を施し、該脱珪処理終了時に、炉内スラグの塩基度を0.8以上1.5以下、溶銑の温度を1280℃以上1380℃以下、溶銑の珪素含有量を0.10質量%以下とし、前記排滓工程では、脱珪処理工程で生成したスラグの30質量%以上を炉外に排出し、その後、炉内の溶銑に前記脱燐処理工程を施し、該脱燐処理工程終了後、脱燐処理した溶銑を出湯し、脱燐処理で生成した炉内のスラグを排出せずに前記転炉型精錬炉内に残留させた状態で新たな溶銑を前記転炉型精錬炉内に装入し、この溶銑に対して予備処理を行うことを特徴とする、請求項1ないし請求項7の何れか1項に記載の溶銑の予備処理方法。 After completion of the dephosphorization process of the pre-charged hot metal in the converter type refining furnace, the hot metal that has been dephosphorized is discharged and the slag generated in the dephosphorization process is discharged without discharging the slag in the furnace. In this state, fresh hot metal is charged into the converter type refining furnace, and the hot metal is subjected to the desiliconization process. At the end of the desiliconization process, the basicity of the furnace slag is set to 0.8. 1.5 or less, the hot metal temperature is 1280 ° C. or higher and 1380 ° C. or lower, the silicon content of the hot metal is 0.10% by mass or less, and in the exhausting step, 30% by mass or more of the slag generated in the desiliconization process Then, the dephosphorization process is performed on the hot metal in the furnace, and after the dephosphorization process, the dephosphorized hot metal is discharged, and the slag in the furnace generated by the dephosphorization process is discharged. New hot metal is left in the converter type refining furnace without being discharged and left in the converter type refining furnace. ON is, and performs preliminary processing on the molten pig iron, molten iron pretreatment method according to any one of claims 1 to 7.
- 排滓工程後の脱燐処理中に炉内のスラグ高さを測定し、上吹きランスからの気体酸素源の供給流量、上吹きランスのランス高さ、底吹き羽口からの攪拌用ガスの供給流量の群から選択された少なくとも1種を調整し、この調整により炉内のスラグが炉口から噴出しないように制御することを特徴とする、請求項1ないし請求項8の何れか1項に記載の溶銑の予備処理方法。 The slag height in the furnace was measured during the dephosphorization process after the exhausting process, the supply flow rate of the gaseous oxygen source from the top blowing lance, the lance height of the top blowing lance, and the stirring gas from the bottom blowing tuyere 9. At least one selected from a group of supply flow rates is adjusted, and control is performed so that slag in the furnace is not ejected from the furnace port by this adjustment. The hot metal pretreatment method according to claim 1.
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JP2016180126A (en) * | 2015-03-23 | 2016-10-13 | Jfeスチール株式会社 | Slag height measuring device, slag height measuring method and preliminary treatment method of hot pig iron |
JP2016197019A (en) * | 2015-04-02 | 2016-11-24 | 新日鐵住金株式会社 | Level gauge, and level measuring method |
CN107002154A (en) * | 2014-12-16 | 2017-08-01 | 杰富意钢铁株式会社 | The preprocess method of iron liquid |
JP2017156345A (en) * | 2016-02-26 | 2017-09-07 | Jfeスチール株式会社 | Antenna for charge level measuring apparatus, charge level measuring method, and converter furnace preparation processing method |
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Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60230929A (en) * | 1984-04-27 | 1985-11-16 | Nippon Steel Corp | Method for operating converter |
JPH03281716A (en) * | 1990-03-30 | 1991-12-12 | Nkk Corp | Instrument for measuring slag level in furnace |
JPH059533A (en) * | 1991-07-01 | 1993-01-19 | Sumitomo Metal Ind Ltd | Method for treating molten iron |
JPH0987722A (en) * | 1995-09-26 | 1997-03-31 | Nippon Steel Corp | Method for refining molten crude stainless steel |
JPH10152714A (en) * | 1996-11-25 | 1998-06-09 | Nippon Steel Corp | Method for refining molten iron |
JP2000273519A (en) * | 1999-03-24 | 2000-10-03 | Kawasaki Steel Corp | Method for removing slag from torpedo car |
JP2001271113A (en) * | 2000-03-27 | 2001-10-02 | Nippon Steel Corp | Converter-refining method for by-producing steel manufacturing slag having low free lime content |
JP2004190101A (en) * | 2002-12-12 | 2004-07-08 | Nippon Steel Corp | Method for pre-treating molten iron |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2038825A1 (en) * | 1990-03-30 | 1991-10-01 | Akio Nagamune | In-furnace slag level measuring apparatus |
-
2014
- 2014-01-20 BR BR112015017155-9A patent/BR112015017155B1/en active IP Right Grant
- 2014-01-20 CN CN201480005778.XA patent/CN104955965B/en active Active
- 2014-01-20 WO PCT/JP2014/000236 patent/WO2014115526A1/en active Application Filing
- 2014-01-20 KR KR1020157017305A patent/KR101751151B1/en active IP Right Grant
- 2014-01-20 JP JP2014524178A patent/JP5761459B2/en active Active
- 2014-01-23 TW TW103102467A patent/TWI576437B/en active
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60230929A (en) * | 1984-04-27 | 1985-11-16 | Nippon Steel Corp | Method for operating converter |
JPH03281716A (en) * | 1990-03-30 | 1991-12-12 | Nkk Corp | Instrument for measuring slag level in furnace |
JPH059533A (en) * | 1991-07-01 | 1993-01-19 | Sumitomo Metal Ind Ltd | Method for treating molten iron |
JPH0987722A (en) * | 1995-09-26 | 1997-03-31 | Nippon Steel Corp | Method for refining molten crude stainless steel |
JPH10152714A (en) * | 1996-11-25 | 1998-06-09 | Nippon Steel Corp | Method for refining molten iron |
JP2000273519A (en) * | 1999-03-24 | 2000-10-03 | Kawasaki Steel Corp | Method for removing slag from torpedo car |
JP2001271113A (en) * | 2000-03-27 | 2001-10-02 | Nippon Steel Corp | Converter-refining method for by-producing steel manufacturing slag having low free lime content |
JP2004190101A (en) * | 2002-12-12 | 2004-07-08 | Nippon Steel Corp | Method for pre-treating molten iron |
Cited By (12)
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---|---|---|---|---|
CN107002154A (en) * | 2014-12-16 | 2017-08-01 | 杰富意钢铁株式会社 | The preprocess method of iron liquid |
CN115074489A (en) * | 2014-12-16 | 2022-09-20 | 杰富意钢铁株式会社 | Pretreatment method of molten iron |
KR20170103850A (en) | 2015-02-10 | 2017-09-13 | 제이에프이 스틸 가부시키가이샤 | Method for inhibiting foaming of molten slag, and method for manufacturing slag product |
CN107208169A (en) * | 2015-02-10 | 2017-09-26 | 杰富意钢铁株式会社 | The foaming sedation methods and the manufacture method of clinker product of molten slag |
JP2016180126A (en) * | 2015-03-23 | 2016-10-13 | Jfeスチール株式会社 | Slag height measuring device, slag height measuring method and preliminary treatment method of hot pig iron |
JP2016197019A (en) * | 2015-04-02 | 2016-11-24 | 新日鐵住金株式会社 | Level gauge, and level measuring method |
JP2017156345A (en) * | 2016-02-26 | 2017-09-07 | Jfeスチール株式会社 | Antenna for charge level measuring apparatus, charge level measuring method, and converter furnace preparation processing method |
JP2018036224A (en) * | 2016-09-02 | 2018-03-08 | 新日鐵住金株式会社 | Level measurement method and level measurement device |
JP2018053347A (en) * | 2016-09-30 | 2018-04-05 | Jfeスチール株式会社 | Slag height measuring device, slag height measuring method and preliminary treatment method of molten iron |
JP2018095935A (en) * | 2016-12-15 | 2018-06-21 | 新日鐵住金株式会社 | Preliminary treatment method for molten iron |
JP7568923B2 (en) | 2021-01-05 | 2024-10-17 | 日本製鉄株式会社 | Refining Method |
JP7568922B2 (en) | 2021-01-05 | 2024-10-17 | 日本製鉄株式会社 | Refining Method |
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