Abstract: A filler sand for a ladle tap hole valve contains 45 to 55 mass % of zircon sand, 30 to 40 mass % of chromite sand and 10 to 20 mass % of silica sand and is blended externally with 0.05 to 5 mass % of carbon black calculated based on the total amount of the sands; or contains 30 to 90 mass % of chromite sand and 10 to 70 mass % of silica sand and is optionally blended externally with 0.05 to 5 mass % of carbon black, wherein 95 mass % or more of the chromite sand consists of particles having diameters falling within a range of 150 to 850 &mgr;m, 60 mass % or more of the chromite sand consists of particles having diameters falling within a range of 212 to 600 &mgr;m, 95 mass % or more of the silica sand consists of particles having diameters falling within a range of 300 to 1180 &mgr;m, and 90 mass % or more of the silica sand consists of particles having diameters falling within a range of 600 to 1180 &mgr;m.

Abstract: An apparatus and method for measuring a temperature of a high temperature liquid contained in a furnace. An optical fiber covered with a metallic tube is inserted through a passageway inside a nozzle arranged on a furnace wall of the furnace. The nozzle communicates with an interior of the furnace containing the liquid, and gas is supplied into the passageway inside the nozzle to prevent the nozzle from clogging. The metal-covered optical fiber is fed through the passageway inside the nozzle into the liquid such that spectral light radiated from the liquid enters a tip of the metal-covered optical fiber and is propagated therealong. The temperature of the liquid is determined by a radiation thermometer, coupled to the metal-covered optical fiber, based on the spectral light propagated along the metal-covered optical fiber.

Abstract: Disclosed is a in-furnace slag level measuring method for measuring a slag level in a convertor and an apparatus therefor. A sublance and an antenna of a microwaver radar are arranged exchangeable therebetween so that the sublance and the antenna are alternatively inserted in to the convertor from about the convertor. The antenna is inserted into the convertor in first and middle stage of the refining operation of the converter to thereby measure the slag level, and the sublance is inserted into the convertor to thereby perform various measurement.