Operation method of ladle refining treatment

An operation method of a ladle refining treatment by which the 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, the operation method comprising

• 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,
• an estimated value Tf of the molten steel temperature is calculated according to the following Formula (1):
• Tf=BMAtd+(BMAtd−BMAtd−α)/α×tr (1)
• where Tf is the estimated value in ° C. of the molten steel temperature at the scheduled ending time, BMAtd is a backward moving average value in ° C. of a continuous temperature measured value at time td, BMAtd−α is a backward moving average value in ° C. of a continuous temperature measured value at time (td−α), td is an operation time in minutes from the start of the continuous measurement of the molten steel temperature to the determination timing, td−α is an operation time in minutes from the start of the continuous measurement of the molten steel temperature to a minutes before td, and tr is a time in minutes from an obtainment time of the estimated value to the scheduled ending time.