We have cement mill with roll press and separator we are facing problem of low feed. W e have analysed the product and our finding are as below less than 3 micron - 12 per cent is in the final product less than 45 micron -17 per cent is in the separator return I think if we can separate this 17 per cent in the separator than our output will increase. Please suggest how should we increase the velocity across the seprator cage and also suggest how to eliminate less than 3 micron particals from the product.

The problem of the -45 micron material in the separator return is known as the "bypass" and is the proportion of fine material that reports to the returns even though it is ground fine enough. Adjustment of the separator speed is unlikely to dramatically improve this. My suggestion would be to conduct trials varying the air flow through the separator and assess which changes improve the performance. The super fine material in the finished product is most likely associated with the ball change grading in the finish grinding ball mill. Reducing the separator bypass may assist in reducing this. Otherwise you will have to tip and regrade the grinding media in the mill and conduct trials as you recharge the mill.

I sent you various mails regarding free lime in clinker. Your response was always very positive. Now I am sending you some data of clinker analysis. Please send your comments (data attached to original file - not available here).

Thanks for the extra data. The K₂O contents between the OPC and SRC are very similar, so again that does not seem to explain the high free CaO on OPC production. Do you know the reason why the clinker LSF is 6 per cent lower than the kiln feed when SRC is being produced, and only 1 per cent lower when OPC is being produced? Presumably the coal feed is the same when producing both clinkers? Are you operating with a bypass? Is the dust loading on the electrostatic precipitator the same when producing bioth clinkers? How are you handling the precipitator dust?