Physical and thermal properties and leachability of Eastern oil shales hydroretorted in a pressurized fluidized bed

Abstract

The physical and thermal properties of spent shale affect the design and characteristics of embankments used for storing the material prior to ultimate disposal. Leaching tests are used to determine if spent shale must be treated as a hazardous material for disposal. The Institute of Gas Technology and the Illinois Institute of Technology conducted tests to determine some physical and thermal properties and leaching characteristics of spent shale samples from six states in the Eastern United States. The samples were processed in the continuous, laboratory scale, pressurized fluidized bed hydroretorting (PFH) reactor at 4.2 MPa (600 psig) and a temperature of about 482 °C (900 °F). The physical and thermal properties determined included particle size distribution, permeability, compressibility, compactibility, consolidation, shear stress, cohesion and thermal conductivity. The samples of spent shale were also agglomerated with air at 1093 °C (2000 °F) to determine the effects on leachability. The results showed that the physical and thermal properties of the six spent PFH shales differ considerably. The results also showed that none of the spent shale samples exhibited any significant metals leachability under the acidic test conditions. In general, thermal agglomeration further reduced the levels of metals leached from the spent shales.