Clinker cooling The cooling of clinker covers the period from when it passes the hottest part of the burning zone until it reaches ambient temperature in storage. The microstructure of the clinker and the properties of the cement which is produced from it can be strongly affected by this stage of production depending on factors such as the distance from the burning zone from the kiln outlet, the range of temperatures through which the clinker minerals pass, the presence of rings or snowmen, whether coating is loose or the cooler  type and the rate of cooling after leaving the rotary kiln. Slow cooling is generally a negative influence on quality for reasons which can be observed by microscopic examination of clinker as discussed below. Matrix crystal size The liquid phase of cement clinker comprises the aluminate phase and the ferrite phase as well as a few others such as the alkali sulphates. When a liquid cools below its crystallisation temperature the size of the cryst