Converter dephosphorization method for high-phosphorus low-silicon molten iron

Abstract

The invention discloses a converter dephosphorization method for high-phosphorus low-silicon molten iron, and belongs to the technical field of steel-making process control. According to the converter dephosphorization method, a smelting process combining partial remained final slag and refined white slag added in the earlier stage is adopted, the final slag remaining amount is that 20-60 kg of final slag is remained in per ton of steel, and the refined white slag adding amount is that 10-30 kg of refined white slag is added into per ton of steel; in addition, the adding amount and the adding time of slagging materials are controlled, and the oxygen supply intensity and the gun position during the smelting process are adjusted, so that the dephosphorization rate of high-phosphorus molten iron smelting reaches 90% or above, and the converter end phosphorus content can be controlled within 0.015% stably; through the full utilization of the pre-melting feature of the refined white slag and the characteristic that the refined white slag contains more Al2O3 and certain CaF2, the slag melting point is reduced, the slag fluidity is improved, and the dynamic conditions for dephosphorization are improved; through the full utilization of the characteristic that the refined white slag has higher alkalinity, high-alkalinity slag can be formed earlier, and the thermodynamic conditions for dephosphorization are improved; as the refined white slag can be recycled, the converter steel-making cost can be effectively reduced.

Description

technical field [0001] The invention relates to a converter dephosphorization method for high-phosphorus and low-silicon molten iron, belonging to the technical field of steelmaking process control. Background technique [0002] The iron and steel market continues to slump, and many iron and steel enterprises have turned their attention to low-priced high-phosphorus ore in order to reduce production costs; the increasing scarcity of iron ore resources has also made the smelting of low-grade, high-phosphorus ore a problem that iron and steel enterprises must face . As the proportion of high-phosphorus ore smelting increases, the proportion of high-phosphorus molten iron in steelmaking converters continues to increase; therefore, how to quickly remove phosphorus from high-phosphorus molten iron to the specified range of qualified molten steel under low-cost conditions has become Many metallurgists research key topics. [0003] At present, the converter dephosphorization meth...

AI Technical Summary

Problems solved by technology

However, for high-phosphorus and low-silicon molten iron, especially low-temperature molten iron, due to insufficient latent heat of molten iron, difficulty in slagging in the early stage, high alkalinity, and small amount of slag, the use of these processes is not conducive to dephosphorization, and may even cause sticking to the gun and flue. and other accidents seriously affect the smooth flow of production

Chinese patent application number 201410470076.0 discloses "a dephosphorization method for producing alloy welding wire steel using high-phosphorus molten iron in a top-blown converter". By adding a large amount of sinter ore to control the early temperature and increase the stirring time of molten iron in the low temperature stage, thereby improving Dephosphorization efficiency, but for high-phosphorus and low-silicon molten iron, the latent heat of molten iron is also insufficient, and the method of increasing a large amount of sinter cannot be used to improve the dephosphorization efficiency