Combined blowing dephosphorization method of converter

Abstract

The invention discloses a combined blowing dephosphorization method of a converter. The method comprises the steps that (1) in the primary stage of combined blowing: combined blowing is carried out through adopting oxygen and nitrogen or an inert gas, the oxygen flow is controlled at 4 to 5 Nm<3> / s, after blowing for 1 to 3 min, nitrogen or the inert gas is batched, and the nitrogen flow or the inert gas flow is 20 to 30% that of oxygen; (2) in the middle stage of blowing: after slags are molten, the oxygen flow is increased to 5 to 6 Nm<3> / s, after the temperature is obviously increased, the nitrogen flow or the insert gas flow is adjusted to 1.1 to 2.2 Nm<3> / s, and the total gas mixture flow is controlled at 6 to 8 Nm<3> / s; and (3) in the later stage of blowing: the maximum total gas mixture flow is not larger than 8.33 Nm<3> / s, and the total oxygen supply is controlled at 12 to 16 m<3> / t during the blowing process. According to the method, high phosphorus molten iron is introduced into the converter, oxygen nitrogen combined blowing is adopted, small-large gas supplies are adopted, the oxygen nitrogen combined injection rate is adjusted, the oxygen supply intensity is guaranteed to meet the oxygen utilization requirement of dephosphorization, mixed gas pressure meets the requirement of dephosphorization power, and dephosphorization and carbon protection are achieved to the greatest extent.

Description

technical field [0001] The invention belongs to the technical field of converter steelmaking, in particular to a converter blowing and dephosphorization method. Background technique [0002] Converter dephosphorization technology mainly relies on the low temperature conditions in the early stage of blowing to achieve the purpose of dephosphorization, which is divided into out-of-furnace dephosphorization and double dephosphorization technology. Dephosphorization outside the furnace is limited by production matching and site, while the double dephosphorization process can meet various production needs. When performing double dephosphorization on a large-scale converter, it is necessary to have a good effect of the bottom blowing of the converter, or use a large oxygen supply intensity; for the case of a large converter without bottom blowing, the dephosphorization effect will be unsatisfactory due to insufficient stirring power; especially in the dry method For double dephos...

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Problems solved by technology

When performing double dephosphorization on a large-scale converter, it is necessary to have a good effect of the bottom blowing of the converter, or use a large oxygen supply intensity; for the case of a large converter without bottom blowing, the dephosphorization effect will be unsatisfactory due to insufficient stirring power; especially in the dry method For double dephosphorization under the dust removal process, if the oxygen supply intensity is increased and the stirring power is increased, the carbon-oxygen reaction will be accelerated, resulting in a rapid increase in the CO content and temperature in the flue gas, resulting in insufficient reaction time for dephosphorization. It is necessary to stop the blowing, otherwise it is very easy for the mixed gas to cause electric field explosion and increase the probability of electrostatic precipitator explosion; if the oxygen supply intensity is reduced, the stirring power will be insufficient, the oxygen supply intensity will be weak, and the full dephosphorization effect will not be achieved.

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