Abstract: A molten iron refining method having, an auxiliary material, and an oxidizing gas supplied through a top-blowing lance, to a cold iron source and molten pig iron that are contained/fed in a converter-type vessel, and molten iron is subjected to a refining process. A pre-charged cold iron source is charged into the converter-type vessel at an amount not larger than 0.15 times. A furnace-top-added cold iron source that's part or all of the cold iron source and added from a furnace top is fed during the refining process. A burner at a leading end of the top-blowing lance that spray holes through which a fuel and a combustion-supporting gas are ejected. During the refining process, a powdery auxiliary material processed into powder that's part of the auxiliary material is blown in, to pass through a flame formed by the burner.

Abstract: A method that, regarding a process of refining molten iron, can increase the thermal margin and the amount of cold iron source to be used. A burner having jetting holes for jetting a fuel and a combustion supporting gas is provided at a leading end part of one lance that top-blows an oxidizing gas to molten iron contained in a converter-type vessel, or at a leading end part of another separate lance. A powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is blown into the molten iron from the one lance or the other lance passes through a flame formed by the burner. This top-blowing lance for a converter is configured to secure a predetermined heating time and powder-fuel ratio. Also, a method for adding an auxiliary raw material and a method for refining of molten iron that use this top-blowing lance.

Abstract: Proposed is a molten iron refining method capable of securing an in-flame staying time period of a heat transfer medium without being influenced by height adjustments of a blowing-purpose oxygen-blowing lance. As far as to a position lower than an upper end inside a converter-type vessel 1, a blowing-purpose oxygen-blowing lance 3 that supplies oxidizing gas and is capable of ascending and descending and at least one burner lance 4 capable of ascending and descending independently of the blowing-purpose oxygen-blowing lance are inserted. From the blowing-purpose oxygen-blowing lance, either oxidizing gas or oxidizing gas and CaO-containing refining agent are blown onto the molten iron. Also, a flame is formed by causing the burner lance to discharge fuel gas and combustion supporting gas. Powder particles discharged from the burner lance are caused to pass through the flame and to be blown onto the molten iron in a heat-transferred state, so that the molten iron is thermally compensated.

Abstract: A variable output device is mounted on a mounting unit with the operating shaft displaceable. An operating unit for transmitting the operation of the user to the operating shaft is mounted on the operating shaft relatively movably along the direction of the axis of the operating shaft, on the one hand, and in an operatively interlocked fashion along the direction of displacement of the operating shaft, on the other hand. A holding member is arranged in opposed relation with the mounting unit with the variable output device interposed therebetween. An elasticity applier urges the operating unit away from the variable output device. The holding member is provided with an operating hole. The holding member is arranged at a position in opposed relation with the mounting unit with the variable output device and the operating unit interposed therebetween.

Abstract: A variable output device is mounted on a mounting unit with the operating shaft displaceable. An operating unit for transmitting the operation of the user to the operating shaft is mounted on the operating shaft relatively movably along the direction of the axis of the operating shaft, on the one hand, and in an operatively interlocked fashion along the direction of displacement of the operating shaft, on the other hand. A holding member is arranged in opposed relation with the mounting unit with the variable output device interposed therebetween. An elasticity applier urges the operating unit away from the variable output device. The holding member is provided with an operating hole. The holding member is arranged at a position in opposed relation with the mounting unit with the variable output device and the operating unit interposed therebetween.