The Swelling Index Furnace, often simply called the free swelling Index (FSI) or Crucible Swelling Number (CSN), measures the swelling behaviour of materials.
The coke ability of coal is an important technological parameter of coals during the reduction process.
Coking properties of coal are evaluated using the Free-Swelling Index (FSI). It is a test that determines the ability of coal to form a coherent mass, or "coke," when heated in the absence of air. This property is crucial for the steel industry, where coking coal is used in the production of coke, a key ingredient in blast furnace operations.
Free Swelling Index is determined by comparing the size and shape of the coke button with a chart of standard profiles and scaling a value from 0 to 9 at an interval of 0.5
