1156 posts
Stoppages Question 1
We are facing severe problem of balling ball size is sometimes around 2m dia which chokes the hammer crusher and we are forced to stop the kiln. What are the possible reasons form such big balls, how is a kiln operater responsible for this, how a kiln operator can avoid such balls through process changes, how we can avoid the balls by changing the chemical composition of kiln feed.
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1156 posts
Re: Stoppages
We hear of these problems with increasing regularity. At one factory the problem was associated with an increase in the Mn2O3 content of the kiln feed associated with one of their additives. There are also instances where an increase in the MgO content of the kiln feed gives rise to balling problems. However, the most likely cause is a difference in the clinkering range of the material in the kiln brought about by variation in the sulphate content. A heavy coating tends to form and the material is then dammed behind this coating and agglomerates into a large clinker ball. You must ensure that there are good combustion conditions in the main burner of the kiln to minimise the recirculating sulphates. The other process response is likely to be an adjustment in either the alighnment or the primary air supply to the main burner of the kiln. Regarding the chemistry then any changes which adjust the liquid content will change the clinkering range in the kiln. Addition of calcium fluoride to the kiln feed is also helpful.
1156 posts
Stoppages Question 2
We have faced the serious coating formation at 12 to 26 meter of Kiln and plant have to be forced stopped for coating removal. I am attaching the three files for your observations:
1. photograph of the Kiln coating.
2. Observation about the breakdown.
3. Analysis data for coating, Rawmix and coal.
I may request you to please look into the coating formation details and furnish us your valuable comments.
1156 posts
Re: Stoppages
I have studied the data you have submitted. We receive regular reports of heavy coating and ball formation associated with petcoke firing. I note that on the 12th & 13th, prior to the kiln stoppage the petcoke firing in the kiln had been increased to 70 per cent. However, the clinker sulphate levels are not excessive and neither is the sulphate in the coating sample. One othet item of note is that the MgO content of the clinker has risen to above 1.5 per cent on the 11th, 12th and 13th. In my experience only minor changes in the MgO content can lead to significant changes in the coating tendency of the kiln and also the formation of clinker balls. Do you know the reason for the increase in MgO content?