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.

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?

I am a consultant to the petroleum coke industry. There is a lot of talk that high sulphur pet coke (7-8 per cent) is a low cost feed to cement plants that meets US emission standards. The theory is that the suphur is thoroughly consumed or bound up by the limestone and converted to calcium sulphate. I have been recently asked by a US cement plant contemplating burning coke for more specific information in order for them to meet their EPA permit. Do you have anything re solid scientific statistics of the SO_x formation in cement kilns when burning coke??

There are a number of case studies of cement kilns burning petcoke and having no SO_x emission problems. It is correct that the predominantly alkaline feed absorbs any SO₂ in the kiln exhaust gases due to the intimate contact between the gases and the feed in the preheater cyclones. There is a greater potential for SO_x emissions with long kilns (ie without preheaters).