I would like to ask about variable chloride values in clinker which can vary from 0.003 to 0.05. Also what will happen if the burner is operated in a reducing atmosphere and how to ensure that the main burner is always operating in an oxidising condition.

The first thing you must do is tie down the source of the variable chloride input to your kiln. This must be in one of the raw materials or the fuel. If one of the raw materials perhaps you can solve the problem by selective quarrying. Operating the burner in a reducing manner will not affect the chloride recirculation but will greatly enhance the sulphate recirculation. If you have any incidence of CO at the kiln inlet then you are operating ina reducing manner and are likely to have sulphate based problems. The way to avoid this is to adjust the flow of fuel and primary air to the burner.

I witnessed a phenomenon at a plant here in Europe, which could not be explained by anybody there. At one plant I found ring formation at the upper transition zone in a rotary kiln at three different areas. The plant is burning alternative fuels like house trash, plastics and bone meal. I was told, that all actions taken with regards to the process, have not been successful. My questions are:
1. Is there anything you could recommend apart of the standard procedures to avoid coating formation?
2. Do you know, if there is any refractory manufacturer who does supply are fractory solution for this matter and what should be the technical data for such a refractory?

The rings you describe must be ash rings formed where the ash from the different alternative fuels combine with the charge in the kiln. It is not uncommon for coating and rings to form at that point in the kiln. As there are three distinct rings I suppose than the different alternative fuels have different aerodynamic properties in the kiln, or different delivery systems injecting them into the kiln and this is causes the ash to combine at different positions. If that is the case I would adjust the different fuel injection velocities to try to even out the coating. I am not aware of are fractory solution to this type of problem in the lower transition zone. I suggest you contact David Shepherd of Ceram Research who will know if such a solution exists, david.shepherd@ceram.co.uk.