Circulating dephosphorization steelmaking method in converter steel slag furnace

Abstract

The invention relates to a circulating dephosphorization steelmaking method in a converter steel slag furnace and belongs to the technical field of metallurgy. The method comprises the steps of firstfurnace smelting, second furnace smelting, third furnace smelting, fourth furnace smelting, fifth furnace smelting, ......, and twentieth furnace smelting. In the first furnace smelting, semi-steel isblended in a furnace, oxygen is blown into the furnace, a first slagging material is added when blowing, the alkalinity of the slag at the end point is controlled to 3-4 to the end of the blowing, splashing of the slag after tapping is performed, and all the steel slag is retained. In the second furnace smelting, the amount of the first slagging material is halved, and the rest procedures are performed in the same way as the first furnace smelting. In the third furnace smelting, a double-slag retention method is adopted, no feeding is needed during the dephosphorization period, the alkalinityof the slag is adjusted to 1.5-2.5, dephosphorization at low temperature is performed, some of the phosphorus-rich slag is poured out, a second slagging material is added for secondary slagging, andall the steel slag is retained. In the fourth furnace smelting, the slagging smelting is performed again by a single slag method, half of the slag is poured out after the tapping, and the smokeless coal gasification dephosphorization is added when the slag is splashed; and the rest procedures are performed in the same way as the second furnace smelting. The procedures of the processes from the fifth furnace smelting to the twentieth furnace smelting are performed in the same way as the fourth furnace smelting. The method is simple, the slagging speed is high, the dephosphorization effect can be ensured under the condition of low auxiliary material consumption, and the steel slag recycling is realized.

Description

technical field [0001] The invention relates to the technical field of metallurgy, and in particular to a method for dephosphorizing steelmaking in which converter steel slag circulates in the furnace. Background technique [0002] Panzhihua Iron and Steel uses vanadium-titanium magnetite for smelting. The main raw material for converter steelmaking is semi-steel after vanadium extraction in a special converter. 4.0%, the content of silicon and manganese heating slagging elements in semi-steel are all traces, the mass percentage content of sulfur in semi-steel is controlled within 0.015%, and the mass percentage content of phosphorus in semi-steel is 0.060%-0.080%, so semi-steel smelting It has the characteristics of less acidic slag-forming substances, single slag system components, and insufficient heat during the blowing process. Therefore, it takes a long time to form the initial slag under semi-steel steelmaking conditions, the dephosphorization rate is low, and the co...

AI Technical Summary

Problems solved by technology

Therefore, it takes a long time to form the initial slag under semi-steel steelmaking conditions, the dephosphorization rate is low, and the consumption of auxiliary materials is large

At the same time, with the increase of steel production, the increasing converter steel slag cannot be effectively recycled, and the pressure on environmental protection is relatively high.