537 posts
re Coating on Nose ring
Hello,
Your hot meal analysis does not show a tendency towards buildups, so slabs falling into the kiln are probably not the cause of the high free lime. Your clinker moduli also indicate that your clinker should not be too hard to burn, based on chemistry alone. (judging by your HM, SM and AM I would guess that your clinker LSF is about 93%.)
What about your raw meal particle size distribution? A high content of coarse quartz (>45um) and/or calcite (>90um) in the raw mix can cause high clinker free lime, even though the raw mix chemistry indicates that it is easy to burn. Do you use a lot of sand or other high quartz corrective in your raw mix? What about coarse calcite? Do you use hard marble as your calciferous component?
Another problem that can cause high free lime in a raw mix of normal average burnability is chemical variability of the kiln feed. Does your kiln feed LSF vary much from hour to hour?
Regards,
Ted.
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20 posts
re Coating on Nose ring
Hellow,
What is your secondary and tertiary air temperature?
If you are maintaining low bed at the cooler inlet then there are possibilities for coating / ring formation at the kiln outlet which can make the kiln operation unstable.
What is your cooler under grate pressure?
Try to increase the cooler fans air flow in the first grate area to the maximum posiible gradually and simultaneously increase the cooler undergrate pressure.
This will results in high secondary and tertiary air temperatue and you will be free of nose ring coating / thickness problem.
Try this and give your feedback.
Best of Luck.
85 posts
re Coating on Nose ring
Sir,
We are keeping a 1st grate undergrate pressure of 450--480 mmAq. Any thing more than this the grate speed will be increased to bring back the clinker bed level back to 450 - 480 mmaq. At this pressure the clinker bed level remains about 500mm. I wish to bring to your notice that our cooler was modified to IKN stationery grates for the 1st 7 rows from the original movable grates. The IKN undergrate pressure is about 800 to 900mm Aq. The reason for keeping this clinker bed level is if it goes more than this then the kiln disturbs very much and we have instances of cooler air flow back pressure which means air will not penetrate the clinker bed and instead it reverse back or so to say it will not push inside.We have tertiary air temp of about 800 to 850 C. We have still not come out of this nose ring coating problem.