Hot clinker is quenched in water losing useful heat, can you syggest heat recovery without altering process of quenching.

The white cement clinker must be quenched as it falls from the kiln to freeze the clinker minerals in their high temperature form. However, this quenching does not need to be to ambient temperature or anything like that. 600 degrees C is sufficient. Therefore quenching in water sprays to this temperature, leaving some sensible heat in the clinker is possible. However, how much useful heat could then be recovered from the clinker is debatable.

We have recently conducted some raw meal burnability testing on samples with varying residue and C₃S. Results showed little dependence on these two variables. Following further investigation I was told burnability can be highly dependent on 45 micron insoluble residue. What are your thoughts on this? I am still reluctant to believe the low dependence on C₃S because in the kiln I am still observing significant fuel variations with changing C₃S.

The classical burnability index takes into account both the chemical composition (i.e. LSF, C₃S etc.) and also the fineness and mineral composition of the kiln feed. The theory is that large quartz (SiO₂)grains and lime (CaO) grains are very difficult to combine in the kiln, and this is fairly well established. You can get the formula from the proceedings of the IEEE 2002 in Jacksonville.