Crucible swelling number

The high-volatile Liddell bituminous coal (Figure 2 (E)) shows little indication of thermally-activated molecular mobility below 500 K. There is some fusion between 500 and 600 K followed by a major fusion transition above 600 K which appears very similar to the high temperature transition of the Amberley coal. This Liddell coal, however, has only 6% liptinite, has a crucible swelling number of 6.5 and exhibits considerable Gieseler fluidity. We therefore attribute this high temperature fusion event to the aromatic-rich macerals of the coal and associate it with the thermoplastic phenomenon. This implies that a stage has been reached in the coalification processes at which aromatic-rich material becomes fusible. 

Free-Swelling Index (Crucible Swelling Number) Roga Index Dilatometer Gray- King... 

The classes of coal are subdivided into groups according to their coking properties, as reflected in the behavior of coals when heated rapidly. A broad correlation exists between the crucible swelling number and the Roga index (ISO methods), and either of these may be used to determine the group number of a coal. 

The only small-scale methods that have stood the test of time and have been accepted as standard plasticity tests are the crucible swelling number, Gray-King coke type, dilatation characteristics, Gieseler plasticity, and, in some countries, the Rogas index. All of these are essentially empirical in nature and many are subjective, at least to some degree. 

The FSI or crucible swelling number (CSN), which is a measure of the ino-ease in volume of the coal when it is heated in the absence of air. This test is also used to characterize coals for combustion. The FSI is at least in part a rank-dependent parameter but also depends on the maceral composition of the coal, the vitrinite maceral group being the main contributor to the swelling properties. 

BSI. 2011. EN-analysis and testing of coal and coke. Part 107 Caking and swelling properties of coal. Section 107.1 Determination of crucible swelling number (BSI BS 1016-107.1). British Standards Institution, London, U.K. 

ISO. 2011b. Coal—Determination of Crucible Swelling Number (ISO 501). International Standards Organization, Geneva, Switzerland. 

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