Method adopting oxygen lance to jet granulated powder limestone to make slag and steel in combined blown converter

Abstract

The invention belongs to the technical field of metallurgy, and particularly relates to a method adopting an oxygen lance to jet granulated powder limestone to make slag and steel in a top and bottom combined blown converter. In the converting step of the steelmaking process of the top and bottom combined blown converter, a top blowing device of the combined blown converter is adopted to simultaneously jet oxygen and granulated powder limestone into a molten pool, the jetting amount of oxygen is 55-65Nm<3> / t molten steel, the jetting amount of the granulated powder limestone is 10-100kg / t molten steel, and coal gas generated by smelting is recovered. According to the method, not only is the implementation of the limestone calcination process transferred to the converter and the energy consumption caused by reheating lime generated after limestone calcination reduced, but also emission of carbon dioxide is reduced; the carbon dioxide generated by limestone decomposition can be mixed into the molten pool to improve the dynamic condition of dephosphorization, and can also serve as an oxygen source to be partially subject to decarburizing reaction so as to improve the quality of gas in the converter; and besides, compared with top adding of a blocky material, when the granulated powder limestone is jetted into the molten pool, slagging and dephosphorization are sped up by virtue of a larger specific surface area and more uniform distribution, so that the converting time is shortened, and the lime consumption and the heat loss are reduced.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for producing slag and making steel by blowing powdery limestone with an oxygen lance in a reblowing converter. Background technique [0002] Most of the current converter steelmaking is carried out by top-bottom combined blowing converter. The common method of top-bottom combined blowing converter steelmaking is to blow oxygen into the molten pool from the upper part of the converter molten pool through the oxygen lance, and add block lime from the top at the same time. , dolomite, fluorite and iron ore and other slagging agents, blow nitrogen or argon and other gases into the molten pool from the bottom of the converter through the bottom gas supply element to stir the molten pool to improve the stirring ability of the molten pool. [0003] The lime used in converter slagging needs to be calcined to obtain limestone. After cooling the lime obtained from ...

AI Technical Summary

Problems solved by technology

[0004] However, due to the relatively large particle size of the massive limestone added through the high-level silo, the decomposition speed of the limestone block is relatively slow, the penetration depth of the limestone is relatively small, the utilization rate of lime is not high, and the isotopic rate of [O] and CaO is not high. It is not conducive to the early dephosphorization of the converter