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.

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).

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??