We have a kiln of 5 m of diameter and 82 m of length. Our thermanl loading in the main burner is 5.3 Gcal/m2/h. I read that increasing the percentage of precalcination and reducing the thermal loading in the main burner the refractory performance can be increased, reaching more than 310 days/year. In our kiln condition, which is a normal performance in days/year?. We use gas as fuel and we have a new burner.