Provided is a method of, in ladle refining treatment of a molten steel, accurately estimating the molten steel temperature after the ladle refining treatment. An operation method of ladle refining treatment by which ladle refining treatment of a molten steel is performed while continuously measuring a molten steel temperature during operation of the ladle refining treatment of the molten steel comprises setting a time earlier than a scheduled ending time of the ladle refining treatment in a continuous measurement period of the molten steel temperature as a determination timing, and estimating the molten steel temperature at the scheduled ending time on the basis of a change with time of the molten steel temperature in continuous measured data of the molten steel temperature from a start of continuous measurement of the molten steel temperature to the determination timing.

The present disclosure provides a converter CO.sub.2—O.sub.2 mixed injection smelting method and a fire point area temperature dynamic control method. The method realizes online monitoring through an infrared temperature sensor installed inside an oxygen lance, dynamically adjusts the mixing ratio of CO.sub.2 and O.sub.2 and the height of the oxygen lance position according to the fire point area temperature changes and process requirements in different smelting stages, so that the secondary smelting system interlockingly and dynamically controls the fire point area temperature and the molten pool heating rate.

A decarburization end point determination method includes: estimating the carbon concentration and oxygen concentration of the molten steel and carbon dioxide gas concentration of exhaust gas in the vacuum chamber by using measurement values of the carbon concentration and the oxygen concentration of the molten steel, a measurement value of internal pressure of the vacuum chamber, and a model formula; correcting a parameter included in the model formula to reduce at least one of a difference between an estimate value and a measurement value of the oxygen concentration and a difference between an estimate value and a measurement value of the carbon dioxide gas concentration of the exhaust gas; estimating the carbon concentration of the molten steel by using the model formula in which the parameter is corrected; and determining timing when an estimate value reaches a target value as the completion time point of the vacuum decarburization treatment.

There is provided a method of dynamic control for a bottom blowing O.sub.2—CO.sub.2—CaO converter steelmaking process. In the process, O.sub.2 is adopted as a top blowing gas, a mixed gas O.sub.2+CO.sub.2 is adopted as a bottom blowing carrier gas to inject lime powders into the converter from a bottom blowing tuyere. The ingredients of the molten steel in the converter steelmaking process are predicted based on the conservation of matter, in combination with the ingredient data of charged molten iron, the ingredient data of the converter gas in the converter blowing process, and working conditions of the bottom blowing device. The top blowing oxygen amount, the bottom blowing gas ratio and the flow rate of lime powder are dynamically adjusted stage by stage according to requirements for target ingredients at the end point of blowing.

A decarburization refining method for molten steel under reduced pressure. The method includes an oxygen-blowing decarburization and a rimmed decarburization. Using operation data taken at a time when oxygen-blowing decarburization is started and a time when oxygen-blowing decarburization is ended, an amount of carbon removed while the oxygen-blowing decarburization is performed is estimated. Based on the estimated amount of carbon removed, a carbon concentration in molten steel at a time when the rimmed decarburization is started is estimated. Using the estimated value as the carbon concentration in molten steel at the time when the rimmed decarburization is started, a change over time in the carbon concentration in molten steel while the rimmed decarburization is performed is calculated. Based on the calculated change over time in the carbon concentration in molten steel while the rimmed decarburization is performed, a determination is made about a time when the rimmed decarburization is ended.

A system and method for monitoring consumption of graphite electrodes during the operation of an electric arc furnace (EAF) uses machine vision cameras operatively communicating with a computer processor. The system can determine, track, manage, and optimize the consumption of the graphite electrodes in real time. Electrode consumption is determined for each EAF heat by measuring the length and tip diameter of the electrode. The length and tip diameter are used to determine the electrode consumption amount using a consumption model. Measured hydraulic pressure within the EAF correlating with a known electrode weight can also be used to determine electrode consumption and correlated with the model calculation. Butt loss can also be determined based on the machine vision measured lengths of the electrode and/or based on the hydraulic pressure. The calculated electrode consumption amounts are also stored in a database and correlated to other measured EAF parameters for multiple EAFs.

A method for operating an electric arc furnace having at least one electrode, the method including the following steps: introducing material that is to be melted in the form of an actual mass flow into the electric arc furnace and feeding electrical energy via at least one electrode into the electric arc furnace in order to melt the introduced material depending on a previously determined, necessary electrical energy input. The necessary electrical energy input into the arc furnace is determined depending on the mass flow input into the furnace.

A system and a method for determining/predicting a tapping time for a metal melt in an electric arc furnace (EAF), at least one electrode is provided for melting the metal melt until it reach a target tapping temperature, the EAF further includes a slag and smoke layer on the surface of the metal melt, wherein an electromagnetic stirrer is provided for stirring the metal melt.

A monitoring method of a steelmaking process in a steelmaking vessel, wherein matters Mn, each having its respective properties PMn, are charged into said steelmaking vessel so as to produce a liquid steel and a slag.

A method and system for predicting slopping in a converter occurring during decarburization refining in the converter in which molten steel is produced from a molten pig iron by blowing oxidizing gas to the molten pig iron in the converter from a top blowing lance, or optionally further blowing oxidizing gas or inert gas from a bottom blowing tuyere to perform the decarburization refining of the molten pig iron. The method includes measuring an emission spectrum of a throat combustion flame blowing out from a throat of the converter, calculating emission intensity of the measured emission spectrum at a wavelength in a range of 580 to 620 nm, and predicting the occurrence of the slopping based on a time-series change of the calculated emission intensity.