Fluorine and molybdenum solubility relationships in combusted oil shale

Abstract

Abstract Fluorine (F) and molybdenum (Mo) may adversely affect vegetation, grazing animals, groundwater, and surface waters that are proximate to spent oil shale disposal sites. The chemistry of F and Mo in spent oil shale leachates may be controlled by the precipitation of flu‐orite (CaF2) and powellite (CaMoO4), respectively. Thus, the fate and behavior of these elements may be predicted using equilibrium solubility methods. Recent findings and the examination of methods cast doubt on the interpretations of many spent oil shale solubility studies. Recent research shows that the formation of soluble molybdate species in spent oil shale leachates can be significant. Further, reaction times necessary for equilibrium conditions were not attained in many solubility experiments. Moreover, solubility experiments were only performed on fresh solid waste, yielding little information on element behavior in a disposal site. The objectives of this study were to reexamine spent oil shale literature data and perform ...