February
The percentage of LC at EMI is usually between 25 and 30%, the rest being MC corresponding to market need. Usually, 1 LC blow is done every 3 or 4 blows.
LC requires a longer blowing time and reaches higher temperature causing accelerated wear on the vessel, in particular if the %Si is higher than 0.15-0.2%. When time is a bottleneck or vessel wear shown by laser is severe or if %Si is above 0.2% in HC, blowing LC will be suspended. It is difficult to compensate for such a period. LC is often done of small to medium tap.
After a period with low production of LC, MOR team started a new strategy to increase amount of LC without penalizing vessel lifetime and tap sequences:
- After a MC blow, some MC (15 to 20klb) is kept is the vessel
- Some new HC is poured on top of it
- The mixture of MC and HC is blown as LC. O₂ factor needed is less since starting %C is less.
This allows to reach a 40% LC ratio over 4 days with minimal impact on wear and time!!!
