Does better nodulisation mean more consistent size of nodules with less dust or with less large nodules ? What might be wrong if always getting a large portion of large nodules (4-6 inches in diameter), even at 25 per cent liquid phase, which isn't high, and ALm of kiln feed ranging from 1.55-1.75. Kiln is typically run at 3.5rpm. The large nodules are only visible on kiln stops when there is a chance to look into the cooler, before the clinker goes through the crusher.

Your chemistry does not sound abnormal and we have discussed the possibility that the large nodules are caused by MgO variation before. A further remote possibility would be Mn₂O₃ variation where slight increases cause the formation of vary large balls and also take the coating out of the burning zone. However, that is a long shot.

How can we reduce the clinker size -5mm >35 per cent (existing),we want to reduce to under 20 per cent. Our plant is a 1Mta capacity unit. Fuel is pet coke 70 per cent balance Indian coal.

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.