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.

Could you please to explain the possibility of steel slag in cement industry as raw material if it was added in the kiln inlet?

Steel slag can certainly be added to the kiln inlet to boost the output from the kiln. This process has been patented by TXI in the USA and is known as Cemstar. The limiting factor is the high iron content of the steel slag which effectively limits the possible addition rate. This subject is discussed in more detail in the February edition of International Cement Review.