Introduction of HBI :
The image below shows the hot briquetting process of HBI production. The DRI (Direct Reduced Iron) is released hot from the reduction process. The hot feed thrust into the nip in the middle of the two counterrotating rollers. The briquettes form in the rotating rollers. The above process happens at 650 -700 °C temperature and with the pressing force of 120 kN/cm. A heavy sliding channel conducts the briquette string to leave the rollers. If briquettes are made of fine, the production happens through a fluidized bed.
The Process:
A roller press, which is designed particularly, is the most important element in hot briquetting.
Generally, for hot briquetting process of sponge iron, the factory consists of:
- Briquetting press has the screw feeder as well as material supply.
- Briquette string separator.
- Hot screen in order to remove fines happens when briquetting and separation.
- A bucket lift is used to return fines to the briquetting press.
- Sliding channel.
On the whole, to simply explain, the production of HBI consists of the following steps:
- Iron pellets get fed into the reactor
- Natural gas is converted into reduction gas and, after that, injected.
- Reduction gas will circulate in a closed system and get recycled
- The direct reduction process:
- Hot natural gas moves into the iron ore from the bottom to the top, according to the counterflow principle
- The oxygen content is reduced, and direct reduced iron (sponge iron) is produced.
- DRI (Sponge Iron) is pressed into the briquettes (Hot Briquetted Iron).