Metallurgical Coal
Coal and Coke Characterization

CONSOL R&D's coal carbonization and coking properties facility can determine the expansion/contraction, agglomerating, and plastic properties of coal or coal blends. The data from these tests aid the customer in selecting coals that have the proper thermo-plastic properties to make high-quality coke.

  • The sole-heated oven test measures the expansion/contraction properties as a volumetric change in a coal charge heated in one direction and under constant load.

  • The agglomerating properties are determined by the Free-Swelling Index tests.

  • The Gieseler Plastometer, Ruhr Dilatometer, and Audibert-Arnu tests determine the thermo-plastic properties.

  • The physical characteristics of the resultant coke are thoroughly evaluated.

The following physical tests can be performed:

  • ASTM Coke Stability and Hardness Index
  • Micum 40 and 10 Index
  • ASTM Shatter Index
  • Screen analyses, average size, and apparent specific gravity

A sophisticated on-site coal analytical laboratory can determine the chemical characteristics of the coke and the coals, including trace elements.

The reactivity characteristics of the coke are determined using the Japanese Nippon I-tester.

Two indices are determined:

  • Coke reactivity index (CRI)
  • Coke strength after reaction (CSR)

The facility is equipped and staffed to perform manual petrographic analyses of coal, coal blends, and coke.

Coking properties of coal
Petrography Microscope

Coal petrography is a fundamental technique for characterizing coals and coal blends and is especially useful when only small quantities of sample are available for testing. Coke petrography is used to determine coal blend proportions, and detect the causes of coke oven operating problems and/or poor coke quality. Coal petrography microscopically determines the maceral composition and vitrinite reflectance of coals or coal blends.

These data can be used to:

  • predict the stability of coke carbonized from coal or coal blends
  • select the coals needed in a blend to meet coke stability requirements and ensure safe coke oven operation
  • determine the effect on coke stability caused by varying the percentages of coals in a blend
  • explanation of any anomalous behavior of coals or coal blends in the coke oven