Process for composite desulfurization of molten iron

Abstract

The invention relates to desulfurizing process of molten iron, which belongs to metallurgy area of iron and steel. The invention molten iron double desulfurization method adopts rotary-type sprayer with agitator on the nozzle. Rotating spray of nozzle cooperates with agitation of agitator to desulfurize molten iron, in which rotary-type sprayer jets desulfurizer into the molten iron while agitator stirs the molten iron. Meanwhile, another desulfurizer CaO is released to molten iron from the top of hot-metal bottle or sack. CaO has the function of desulfurizating and thickening desulfurizing slag, which saves densifier compared with present technology. When sprayer jets desulfurizer, nitrogen is adopted as carrier gas and dense-phase is adopted to transport desulfurizer, which comprises anyone or combination of more than two of Na2O, CaO, CaC2 and Mg and takes the formation of powder. This invention has the following properties: perfect effect of desulfurizating (sulfur content of molten iron can drop to <=0.005% after desulfurizing process), low temperature drop (approaching <=1 DEG C / min), low cost of desulfurizer (0.2-0.5kg / tmolten iron) and good comprehensive economic effect (especially adapting to molten iron desulfurizating in mini-steel plant).

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy and relates to a molten iron desulfurization process. Background technique [0002] In the prior art, hot metal desulfurization is a widely used process. With the gradual promotion of molten iron desulfurization technology in my country, various desulfurization technologies have also been adopted one after another. From the desulfurization of iron gutters to desulfurization of torpedo tanks or ladles, desulfurization agents have developed from soda, calcium carbide powder, and lime to pure magnesium. The way of adding the agent has been developed from artificial and launder to spray gun injection, and finally formed two methods: stirring method and injection method. However, small-capacity molten iron ladles (or tanks) are commonly used in small and medium-sized blast furnaces. The above two methods alone cannot meet the requirements of molten iron desulfurization. Slagging before and aft...

AI Technical Summary

Problems solved by technology

[0006] Small-capacity molten iron ladles (cans) are used in small converters and small blast furnaces, and most of them are old enterprises that have been in operation for many years. Many small blast furnaces supply molten iron for one or two steelmaking plants. The transportation distance of molten iron is long, and the temperature of molten iron big loss

The temperature and sulfur content of molten iron in different blast furnaces are very different. In addition, the liquid level of each tank of molten iron is unstable and the space for the molten iron tank is small. Therefore, direct desulfurization of molten iron ladles (cans) faces many difficulties.