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Definition of clinker

i. Fused or partly fused coal ash, a byproduct of combustion. According to Grapes (2006) it is now concerning fused and/or partially melted sedimentary rocks coming from coal seams or bituminous sediments. Glassy clinkers, that are sometimes named scoria, are in fact buchites. Characteristic features of clinkers is its resemblane of pavement brick (klinkaerd) and a "metallic" sound when hit by a hammer. Clinkers are the most common rocks found in burning coal mining dumps and are usually red or pink, hard, having well preserved shaly texture. They are usually composed of quartz, partially/fully dehydrated clay minerals, and minor mullite. Some similar rock, yellow or white in colour, are also found. All these shaly pyrometamorphic rocks may be called metapelites. They may contain cristobalite. White clinker-like rocks may be called porcellanites.

Compare with: core

Ref: ACSG, 2

ii. Coal that has been altered by an igneous intrusion.

See Also: natural coke

iii. Partially fused intermediate product in the manufacture of portland cement.


Grapes (2006): Pyrometamorphism. Springer-Verlag, Berlin, Heidelberg

Kruszewski, Ł. - personal field observations and analyses

A typical coal-fire clinker (from a burnt mining dump):

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