Method for reducing nitrogen increase of molten steel in LF refining process

• Main Authors: ZENG HUI, CHEN WANFU, YUAN YUHAO, HU TINGJUN, LUAN JIYI, DONG HUI, WANG NIANXIN, WU JIYU, LI CHANGXIN, ZHANG GE, ZHAO MIN, DONG HONGZHUANG
• Format: Patent
• Language: Chinese; English
• Published: 28.02.2023
• Subjects: CHEMISTRY; METALLURGY; METALLURGY OF IRON; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS

The invention relates to the technical field of steelmaking LF refining, in particular to a method for reducing nitrogen increase in molten steel in an LF refining procedure, which comprises the following steps: (1) before a steel ladle enters the refining procedure, uniformly spreading small-granularity limestone with the granularity of 1-3mm on the upper part of a steel ladle slag layer in advance, continuously generating CO2, and ensuring continuous micro-positive pressure and a CO2 bubble isolation layer on the upper part of the slag layer; (2) opening a steel ladle to blow argon from the bottom to carry out weak stirring, so that the small-granularity limestone and the steel ladle slag are uniformly mixed; at the high temperature of the ladle slag, CO2 bubbles generated by decomposition of small-particle-size limestone form a sealed isolation layer, and meanwhile, the argon flow is controlled for weak stirring, so that the molten steel is effectively prevented from being exposed to be in contact with air