How to explain the negative B value and mere shrinkage of a single type of coal
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Why for the same type of coal, when sampling twice, is one of the B values -7?； The other one is contraction only; please explain if you don’t understand
This post was last edited by Graduation snack on 2015-8-21 at 17:37. The B value for the expansion degree of Oa that you mentioned is negative; it’s a type of QM, I guess. For the same type of coal, the degree of metamorphism can vary, and combined with experimental errors, this phenomenon is quite normal. Generally, the b-value is used to distinguish between coal types with high caking properties (1/3 coke, FM, JM); it doesn’t have much significance as a reference for other types of coal for now. You can compare the Oa curves and b values for all QMs to see if there is both contraction and negative expansion.
Also, is your coal type a finely processed blended coal, or coal supplied directly from the mine?