Your idea is a very good one. There are plants that do exactly what you propose. This has the advantage that the chemistry of the kiln feed is more stable because it is not destabilised by slugs of ESP dust being added to the homegenisation silo when the raw mill is not running. I am not sure that you will get more output but the kiln operation and clinker quality should be more stable.

I would like to ask two questions (1) what influence has the fineness in the slurry in wet process in low/normal operation what happens in the kiln and chemistry change and the life of the refractary? (2) what happens in the kiln when burned the slurry with a moisture about 40-43 per cent especially the life of the refractory?

When the fineness of the slurry is low then potentially it will be more difficult to combine into clinker. This is not a chemistry change but the fact that there are larger particles means that conversion into the clinker minerals is more difficult as this is a solid state reaction and is dependent on the surface area and contact between the particles. Because the clinker combination is more difficult more fuel will need to be burnt and this could adversely affect the refractory life. The same applies to a high slurry moisture content. Because there is more water to evaporate in the kiln more fuel must be burnt. Again this can cause the refractory life to be reduced.

We are getting very high free lime in clinker. Some times it goes up to 5 per cent. Normally it remains 2 to 2.5 per cent. We are firing 100 per cent South African and Chinese origin coal. Our kiln feed analysis is 95 -96 per cent LSF, 2.35 Silica Modulus, and 1.85 - 1.900 Alumina modulus. In clinker we get 92 per cent, LSF, 2.10 SM and 2.1 AM. We are using Duoflex burner of FLS. What is your opinion about the causes of free lime.

There could be a number of causes of the high free CaO content of your clinker despite the fact that the lime saturation of the clinker is only 92 per cent. The fineness of the kiln feed is one factr and also the contents of MgO and K₂O. If you can tell me those I will be in a better position to diagnose the problem.