We are experiencing a ring at the 5-7m mark from the outlet after running the kiln for about a week. Our kiln is 50m ling and 3.8m diameter. Kiln feed fineness is around 19% residues on 90micron sieve, there has been no change in alkali and sulfur content. What could be the cause of the ring? and how can we distingnguish between a sulphur, spurrite and alkali ring. Can somebody recommend some literature on ring formation, causes etc?
thank you
Are you still experiencing this ring formation Naison? At that position the root cause is most likely excessive SO3 circulation. Have you tested the hot meal SO3 (and chloride)? Adjustment of the main burner and ensuring good combustion of the fuel there is the most likely solution.
Dr Michael Clark
A ring was beginning to form just before we stopped the kiln due to snowman built up in the gratecooler .I had not done an SO3 analysis in the hot meal but I have taken note of your advise, currently we are analyzing clinker SO3 at 2 hour intervals. Would that not give an indication of a sulphur built build up? The SO3 in clinker is ~1.3%
No Naison, the SO3 content of clinker will not tell us the degree of SO3 concentration or potential build-up formation. We have to have the concentration in the hot meal.
Dr Michael Clark