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.