Converter later-stage low-temperature tapping efficient dephosphorization method

Abstract

The invention discloses a converter later-stage low-temperature tapping efficient dephosphorization method. The method comprises the following steps that Si, Mn and part of iron in slag are oxidized by adopting high lance position and large oxygen flow in the early stage of blowing; with the continuation of oxygen blowing, CO gas generated by chemical reaction of carbon and oxygen enables the early-stage slag to be prone to emerge, the lance position is raised, and the oxygen flow is reduced; the lance position is lowered in the middle stage of blowing; in the middle and later stages of smelting, the lance position is increased for slag adjustment, a part of sinter is added in multiple batches, the dephosphorization effect of the slag is good, and meanwhile good thermodynamic and dynamic conditions are achieved; and then a sublance is put down for TSC, and in the later stage of smelting, the final TSO temperature is controlled to be 1590-1620 DEG C . According to the method, an in-furnace efficient dephosphorization production process under a converter end-point low-temperature tapping condition is provided, and by reducing tapping end-point temperature, the distribution ratio of phosphorus in slag and steel in the later stage of smelting of a converter is increased, and therefore the dephosphorization efficiency in the later stage of smelting is improved.

Description

technical field [0001] The invention belongs to the technical field of iron and steel production, and in particular relates to a method for high-efficiency dephosphorization of steel at a low temperature in the later stage of a converter. Background technique [0002] The dephosphorization reaction in steelmaking mainly occurs at the steel-slag interface. By increasing the basicity, increasing the temperature, and increasing the stirring capacity of the molten pool (top-bottom double blowing effect), the dephosphorization reactants and products can be increased in the steel slag. The diffusion coefficient at the interface increases the dephosphorization speed of the converter. [0003] At present, the existing converter dephosphorization process in China is mainly dephosphorization in the early stage of smelting. The key points of its operation are to use a low ratio of steel scrap into the furnace, and use a high lance position and high oxygen supply intensity in the early ...

AI Technical Summary

Problems solved by technology

[0004] The traditional converter steelmaking dephosphorization process established on the basis of thermodynamics and kinetics consumes 40-60 kg of lime, 12-20 kg of lightly burned dolomite, and produces 90-120 kg o

Images