We determinate free lime by X-ray, but when we make a program to determinate it. This program has a life period about one month, after that, the program starts to give wrong results and we can?t calibrate it, because the problem becomes bigger. What can we do to eliminate this problem and what can we to do to improve the program.

I presume you are using X-ray diffraction to determine the free lime but the problem is that the calibration drifts with time. I suggest that you measure the free lime by traditional titration once per day. The program can then be modified to continuously update the relationship between the free lime and the XRD intensity using the last 20 results. In this way the calibration will be continuously updated and there will be no need to make a special recalcibration once per month.

We're suffering from brown clinker. As the results of microscopic analyses, there surely should be reducing condition in the burning of the kiln. So we increased the cooling air flow into the kiln to supply sufficient oxygen. It's getting better but we still have brown clinker. We can't increase the cooling air rate anymore because we already operated the exhaust fan with fully opened condition. So we're considering reducing the coal flow rate. It means clinker production should be decreased. What's the next methods we can do except reduction of throughput production to avoid the brown clinker.

It sounds to me that you must have combustion problems. I recommend that you should contact specialists and pay for a combustion audit. This will be the best way to find the solution. You might try increasing the primary air flow of the burner to maximum, or reducing the secondary air temperature by running the cooler grate with a lower under-grate pressure setpoint.