Due to the use of sulfur-containing fuels in the blast-furnace process, hot metal always contains a certain amount of sulfur. Depending on the steel grade being produced, this amount has to be reduced to a defined level before the hot metal can be converted to high-grade steel in the converter. The necessary desulfurization agents can either be blown into the bath with a lance or poured onto the bath and distributed with a mechanical stirrer. Which alternative is more economical for a steel works operator depends on many different variables, including the availability and quality of raw materials, the prices of desulfurization agents and also individual conditions in the works.

 

Unlike in the injection process, the Simetal HM KR Desulf process involves placing the desulfurization agent in the hot-metal bath with a mechanical stirrer. The system is based on a robust and low-maintenance design and is particularly suitable for large batches. As from a batch weight of about 150 metric tons, desulfurization takes around ten minutes and is thus faster than in the injection process. Final sulfur content values of 0.002 percent can be achieved. Another advantage lies in process frugality with regard to the desulfurization agents used. Reproducibly good results are possible even with low-grade burnt lime, which is frequently used as a by-product in steel works. Expensive desulfurization agents, such as high-grade burnt lime or magnesium, or those that are difficult to handle, for example calcium carbide, no longer need to be procured separately.