The only way to change the clinker size will be to change the kiln feed chemistry or the operation of the kiln. To have less fines in the clinker you should try to increase the flux content by reducing the silica modulus. Alternatively, adjust the rotational speed of the kiln by slowing slightly to increase the residence time.

Do you have an idea of each point decreased in the standard deviation of the kiln feed and how it affects to the specific heat consumption? (for example:40 kj/kg of clinker for every additional 0.1 by which the standard deviation is raised in the usual range).

The effect of kiln feed standard deviation on unit energy consumption is complex and is likely to vary from kiln to kiln. For a precalciner kiln each one per cent increase in the standard deviation of the kiln feed lime saturation factor you might expect an increase in the energy consumption by 150 kJ/kg clinker. However, this relationship is unlikely to be linear and will vary around that figure from kiln to kiln.

Is there a formula for determining the correlation between kiln feed rate and kiln speed?