Composite desulfuration method for molten iron

Abstract

The invention relates to molten iron desulfurization technology. It adopts rotating airbrush tool and pulse type whisking system that the spraying head has blender, while adding the desulfurizer, the blender whisking the molten iron. The whisking method could be negative or positive two-way whisking, or rotate-stop-rotate pulse rotating whisking. Another kind of desulfurizer could be added into molten iron and spraying little nitrogen gas into molten iron. The invention has good desulfurization effect, and the sulfur content could be less than 0.001% after being treated. And it has little temperature drop, less than 1 degree centigrade / min. The consumption of desulfurizer is low, about 0.2-0.5kg / t molten iron. It has good integrated economic effect.

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

When rotating in one direction, a large vortex rotating in one direction is formed in the center of the molten iron surface. At this time, the amount of desulfurization agent involved in the liquid is proportional to the rotation speed of the agitator, but when the agitation speed reaches a certain value, the desulfurization effect is not good. What is the reason for the increase? Through research, it is found that when rotating in one direction, the desulfurizer particles are rarely involved in the molten iron liquid, but rotate together with the liquid. The speed difference between the two is different at first, and then becomes more The smaller the size, the smaller the collision and mixing effect, most of the desulfurizer particles are still suspended on the liquid surface, although the center forms a vortex, but the reason for its formation is that the entire liquid is pushed to the edge by the centrifugal force, and the center liquid level height Therefore, the lowering forms a vortex, and at the same time, the liquid level at the edge rises. The center only rotates faster than the edge, and the desulfurizer particles and the liquid also rotate together. There is no speed difference, and there is no force to entrain the liquid. The larger the value, the longer the rotation time, the smaller the speed difference between the two, and finally reach a stable value, so the desulfurization effect is no longer improved

Images