BLOWING LANCE FOR REFINING, BLOWING LANCE APPARATUS FOR REFINING, METHOD OF DESILICONIZING OF MOLTEN IRON, AND METHOD OF PRETREATMENT OF MOLTEN IRON

摘要

A gas blowing lance (1) for blowing oxygen gas into a molten metal. It has a double-tube structure comprising an inner tube (2) and an outer tube (3). Oxygen gas is blown through the inner tube, and a hydrocarbon gas is blown through the space between the inner tube and the outer tube. An Al2O3-MgO monolithic refractory having an MgO content of 5-30 mass% is used as a refractory coating layer for at least a blowing end part of the outer periphery of the outer tube. The lance hence has high durability and can be used more times than conventional ones. It contributes to a reduction in production cost. Also provided is a method of the desiliconizing of molten iron which uses the blowing lance.