Re: Physical Appearances of Clinker and Its Implications
Clinker colour is largely governed by the ferrite (C4AF) content. (The lower the C4AF the lighter the cement made from that clinker.) However colour can also be significantly influenced by trace metals, degree of burning, reducing conditions in the burning zone and the extent of oxidation of the ferrite phase during cooling.
Iron, manganese, zinc, titanium and chromium all cause clinker to become darker. Reducing conditions and high burning zone temperature cause the clinker to become lighter because of the reduction of Fe+3 to Fe+2. Significantly under-burnt clinker can also produce a noticably lighter cement.
The implications of colour changes are often as important to the customer as cement performance. But that depends a lot on the type of application for which the cement is used. For example, significant changes in concrete colour during a large volume project such as a bridge or high-rise building could be disasterous for cement sales.
I'm not sure what you mean by texture. Are you talking about the texture of the interior of nodules? (ie porosity/density)