The advanced Outotec® Ferrochrome Process to produce pellets with steel belt sintering and utilizing our patented preheating method before smelting has many competitive benefits. Using pellets with lumpy ore in smelting improves the recovery of chrome. The average power and utilization rate increases. The energy consumption falls and ferrochrome production increases.
Outotec provides solutions for ferroalloy smelting in the closed submerged arc furnace (SAF) equipped with charge material preheating in the stationary Outotec Preheating Kiln (OPK™), located on top of the SAF. The preheating energy is obtained from the off-gas of the smelting furnace, rich in CO gas (typically 80–88 %). The gas is first cleaned in efficient Outotec-type gas scrubbers and and can be stored in a reservoir tank before use. The possibility to further clean the CO-gas before use and storing exists thanks to the new Outotec CO-gas plate filters.
The stationary OPK™ also works as a buffer between batching and smelting, allowing some maintenance work in dosing without stopping the process. Furthermore, in case of disturbances in the gas lines, you can switch off the OPK™ without an immediate effect on smelting in the furnace.
As a result of our vast know-how and experience, we have been able to increase furnace size to 78 MVA (65 MW) and capacity is increasing. We are committed to continuous development of our processes, and just recently we applied for a patent for our new furnace roof structure.
Benefits of using high-quality pellets for ferrochrome smelting:
- Enables use of low-cost chromite fines
- Increases production in existing furnaces
- Furnaces can be closed and utilize the CO gas and preheating in the OPK™
- Enables bigger production units
- Smaller unit costs.
Clean scrubber outlet gas
The very finest particles are difficult to collect through wet scrubbing. The latest approach to the subject is a ceramic filter that facilitates the removal of particles that pass through the scrubbers. Ceramic filters are becoming an elementary part of furnace gas cleaning.
CO-gas can be used as a source of secondary energy, which on one hand saves primary electric energy in ferrochromium production and, on the other, replaces other fossil fuels at the adjacent works. Utilization of the gas has a high impact on total dust and gaseous emissions and on energy optimization at ferrochromium and steel works.
Taking advantage of the CO-gas, which is produced and released during the ferrochrome process, is also vital from an environmental perspective.
Advantages of clean CO-gas:
- Possibility to use CO-gas for more demanding purposes
- The operation of CO-gas valves remains good
- Longer equipment lifetime due to low lining deterioration