Batch Charging • The benefits of DRI/HBI are not limited to its chemical characteristics. In electric furnace steelmaking, the use of high density DRI/HBI can eliminate the need for a second or third scrap charge. This results in lower energy losses, more power-on time and improved productivity. Midrex DRI or HBI is mixed with scrap in the bucket. Generally, DRI or HBI can be added at up to 20% of the charge. 

Continuous Charging • Continuous charging systems can be used to feed up to 100 percent of the required metallics. More commonly, one bucket of scrap is charged, and the remainder is continuously fed DRI or HBI. This can reduce back charges and allows the furnace roof to stay on, retaining valuable heat. Maintaining a consistent temperature leads to improved bath heat transfer and faster metallurgical reactions.  Continuous charging can be done with cold or hot DRI. Hot DRI can be charged directly using the MIDREX HOTLINK®  System, or using transfer containers or a conveyor. Normally, the DRI is charged to the center of the EAF.

BLAST FURNACE
HBI has been widely used in blast furnaces to increase hot metal production and lower coke consumption. Blast furnace production can be increased by over 20 percent by using DRI/HBI in the burden. This increase can be realized with no capital cost expenditures. Its use is cost effective when the steelworks is hot metal short or if a blast furnace is down for a reline or idled until hot metal demand increases.

BOF
In cases where the feed materials may cause chemistry or residual problems, DRI/HBI can be charged to a BOF to supplement or replace choice scrap. DRI/HBI is also valuable as a vessel trim coolant to reduce the temperature of hot heats. Compared to conventional coolants, iron ore and limestone, DRI/HBI provide better iron yield for the same amount of cooling and will not result in further oxidation of the steel or vessel slopping. DRI/HBI can also be added to the ladle at tap to cool the steel which will save time and reduce tap-to tap times.

Sourced from MIREX