The composition of the coal has affected the melt content of your clinker. This is affecting the kiln torque because stickiness in the charge in the kiln has changed and is not climbing the rotating walls of the same extent. This also explains the increased density of the clinker. However, you are not suffering any other operational problems, which is a good result with such a major change in operations. Congratulations!

We are Clinker traders based in the UAE, and wish to start supply of coal to our clients in UAE. Wish to know at a very basic level - average consumption of coal per unit of cement produced. (one unit = 1 metric ton). The problem is I am getting a lot of varied opinions, and want to have accurate info before venturing into new trade.

At a basic level 0.1 tonnes of coal is used per tonne of cement produced.

We are getting very high free lime in clinker. Some times it goes up to 5 per cent. Normally it remains 2 to 2.5 per cent. We are firing 100 per cent South African and Chinese origin coal. Our kiln feed analysis is 95 -96 per cent LSF, 2.35 Silica Modulus, and 1.85 - 1.900 Alumina modulus. In clinker we get 92 per cent, LSF, 2.10 SM and 2.1 AM. We are using Duoflex burner of FLS. What is your opinion about the causes of free lime.